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Barati H, Fekrirad Z, Jalali Nadoushan M, Rasooli I. Anti-OmpA antibodies as potential inhibitors of Acinetobacter baumannii biofilm formation, adherence to, and proliferation in A549 human alveolar epithelial cells. Microb Pathog 2024; 186:106473. [PMID: 38048840 DOI: 10.1016/j.micpath.2023.106473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 11/25/2023] [Accepted: 11/28/2023] [Indexed: 12/06/2023]
Abstract
Outer membrane protein A (OmpA) is a critical virulence factor in Acinetobacter baumannii, influencing adhesion, biofilm formation, host immune response, and host cell apoptosis. We investigated the invasion of A549 alveolar epithelial cells by A. baumannii and examined how anti-OmpA antibodies impact these interactions. OmpA was expressed and purified, inducing anti-OmpA antibodies in BALB/c mice. The potential toxicity of OmpA was evaluated in mice by analyzing histology from six organs. A549 cells were exposed to A. baumannii strains 19606 and a clinical isolate. Using cell culture and light microscopy, we scrutinized the effects of anti-OmpA sera on serum resistance, adherence, internalization, and proliferation of A. baumannii in A549 cells. The viability of A549 cells was assessed upon exposure to live A. baumannii and anti-OmpA sera. OmpA-induced antibody demonstrated potent bactericidal effects on both strains of A. baumannii. Both strains formed biofilms, which were reduced by anti-OmpA serum, along with decreased bacterial adherence, internalization, and proliferation in A549 cells. Anti-OmpA serum improved the survival of A549 cells post-infection. Pre-treatment with cytochalasin D hindered bacterial internalization, highlighting the role of actin polymerization in invasion. Microscopic examination revealed varied interactions encompassing adherence, apoptosis, membrane alterations, vacuolization, and damage. A549 cells treated with anti-OmpA serum exhibited improved structures and reduced damage. The findings indicate that A. baumannii can adhere to and proliferate within epithelial cells with OmpA playing a pivotal role in these interactions, and the complex nature of these interactions shapes the intricate course of A. baumannii infection in host cells.
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Affiliation(s)
| | | | - Mohammadreza Jalali Nadoushan
- Department of Pathology, School of Medicine, Shahed University, Tehran, Iran; Molecular Microbiology Research Center and Department of Biology, Shahed University, Tehran, Iran.
| | - Iraj Rasooli
- Department of Biology, Shahed University, Tehran, Iran; Molecular Microbiology Research Center and Department of Biology, Shahed University, Tehran, Iran.
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2
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Wang W, Yi Z, Cai W, Ma J, Yang H, Zhou M, Xiao X. Differences in Bacterial Communities of Retail Raw Pork in Different Market Types in Hangzhou, China. Foods 2023; 12:3357. [PMID: 37761065 PMCID: PMC10529276 DOI: 10.3390/foods12183357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Revised: 08/27/2023] [Accepted: 08/28/2023] [Indexed: 09/29/2023] Open
Abstract
Pork is widely consumed globally, and pigs' microbiota can potentially harbor foodborne pathogens. Contaminated pork in retail markets poses significant implications for food quality and safety. However, limited studies have compared pork microbiomes in various marketing environments. In this study, we utilized traditional microbial culture methods and high-throughput 16S rRNA sequencing to assess pathogen contamination and bacterial diversity in raw pork samples purchased from farmers' markets and two types of supermarkets (upscale and ordinary) in Hangzhou, China. Traditional microbial plate cultures identified E. coli and Salmonella spp. in 32.1% (27/84) and 15.5% (13/84) of the collected pork samples, respectively. Moreover, 12 out of 13 Salmonella strains were found in farmers' markets. The MIC results indicated a high prevalence of MDR strains, accounting for 51.9% in E. coli and 53.8% in Salmonella. The prevalence of NaClO tolerant strains was 33.3% and 92.3% for E. coli and Salmonella, respectively. Sequencing results indicated significantly higher microbial diversity in farmers' market samples compared to supermarket samples. Farmers' market pork samples exhibited a greater abundance of Acinetobacter, while Pseudomonas and Brochothrix were predominant in supermarket samples. The total abundance of pathogenic and spoilage bacteria was also higher for the farmers' market samples. Cross-contamination during market trading was evident through a high correlation between bacterial abundance in pork from different stalls within the same farmers' market. PICRUSt2 analysis identified significant differences in the average proportions of genes for carbohydrate, energy, and lipid metabolism from the farmers' markets, suggesting an exacerbation of microbial metabolic activity and increased perishability of pork in this environment. In conclusion, this study revealed variations in the characteristics of raw pork bacterial contamination across different types of retail stores, as well as differences in the composition and diversity of their respective bacterial communities.
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Affiliation(s)
- Wen Wang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, MOA Laboratory of Quality & Safety Risk Assessment for Agro-Products (Hangzhou), Institute of Agro-Product Safety and Nutrition, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China; (W.W.); (Z.Y.); (J.M.); (H.Y.)
| | - Zhengkai Yi
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, MOA Laboratory of Quality & Safety Risk Assessment for Agro-Products (Hangzhou), Institute of Agro-Product Safety and Nutrition, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China; (W.W.); (Z.Y.); (J.M.); (H.Y.)
| | - Wei Cai
- College of Food Science and Engineering, Wuhan Polytechnic University, Wuhan 430048, China;
| | - Jiele Ma
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, MOA Laboratory of Quality & Safety Risk Assessment for Agro-Products (Hangzhou), Institute of Agro-Product Safety and Nutrition, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China; (W.W.); (Z.Y.); (J.M.); (H.Y.)
| | - Hua Yang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, MOA Laboratory of Quality & Safety Risk Assessment for Agro-Products (Hangzhou), Institute of Agro-Product Safety and Nutrition, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China; (W.W.); (Z.Y.); (J.M.); (H.Y.)
| | - Min Zhou
- College of Food Science and Engineering, Wuhan Polytechnic University, Wuhan 430048, China;
| | - Xingning Xiao
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, MOA Laboratory of Quality & Safety Risk Assessment for Agro-Products (Hangzhou), Institute of Agro-Product Safety and Nutrition, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China; (W.W.); (Z.Y.); (J.M.); (H.Y.)
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Li Y, Liu L, Xiao C, Sun B, Luo S, Yang D, Zhang X, Huang T, Yu Z, Li X. Outer membrane protein A of Acinetobacter baumannii regulates pulmonary inflammation through the TLR2-NF-κB pathway. Vet Microbiol 2023; 284:109812. [PMID: 37343456 DOI: 10.1016/j.vetmic.2023.109812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 06/07/2023] [Accepted: 06/10/2023] [Indexed: 06/23/2023]
Abstract
Acinetobacter baumannii (A. baumannii) is characterized by a high prevalence of drug resistance; how to effectively treat it is still a major clinical challenge. Our previous experiments confirmed that ompA, which is one of the most well-characterized virulence factors, may be dependent on the caspase-1 pathway-stimulated expression of NLRP3 inflammasome to enhance inflammation. TLRs (i.e., TLR2, etc.) is the initiating signal for NLRP3 inflammasome activation; how it relates to ompA in its underlying pathogenic mechanism is not clear. In this study, we proofed that ompA promoted NLRP3 inflammasome activation while the TLR2-NF-κB pathway was also activated after A. baumannii infection. Additionally, the expression of NLRP3 inflammasome-associated proteins and genes was inhibited by silencing TLR2 and NLRP3. This indicated that ompA might depend on the TLR2-NF-κB pathway to assemble and activate the NLRP3 inflammasome. OmpA promoted the assembly of the NLRP3 inflammasome through the TLR2-NF-κB pathway and inhibited the degradation of caspase-1 by the proteasome so that a large number of mature IL-1β/IL-18 and other proinflammatory factors were released extracellularly to enhance the body's inflammatory response. Taken together, the results of the joint pre-study confirmed a novel TLR2-NF-κB/NLRP3/caspase-1-modulated mechanism underpinning ompA activity, the NLRP3 inflammasome pathway may be as a potential immunomodulatory target against A. baumannii infections.
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Affiliation(s)
- Yumei Li
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Nephrology, Guiyang First People's Hospital, Guiyang, Guizhou 550025, China
| | - Laibing Liu
- Department of Neurosurgery, Affiliated Hospital of Guizhou Medical University, Guiyang, Guizhou 550004, China
| | - Chaolun Xiao
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Nephrology, Guiyang First People's Hospital, Guiyang, Guizhou 550025, China
| | - Baofei Sun
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Nephrology, Guiyang First People's Hospital, Guiyang, Guizhou 550025, China
| | - Shipeng Luo
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Nephrology, Guiyang First People's Hospital, Guiyang, Guizhou 550025, China
| | - Dan Yang
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Nephrology, Guiyang First People's Hospital, Guiyang, Guizhou 550025, China
| | - Xiangyan Zhang
- Department of Respiratory and Critical Medicine, Guizhou Provincial People's Hospital,Guiyang, Guiyang, Guizhou 550006, China
| | - Tao Huang
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Nephrology, Guiyang First People's Hospital, Guiyang, Guizhou 550025, China
| | - Zijiang Yu
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Nephrology, Guiyang First People's Hospital, Guiyang, Guizhou 550025, China.
| | - Xiaoying Li
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Nephrology, Guiyang First People's Hospital, Guiyang, Guizhou 550025, China
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Islam A, Actis LA, Wilson TJ. Natural Antibodies Mediate Protection Against Acinetobacter baumannii Respiratory Infections. J Infect Dis 2023; 228:353-363. [PMID: 36951192 PMCID: PMC10420402 DOI: 10.1093/infdis/jiad069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 02/22/2023] [Accepted: 03/21/2023] [Indexed: 03/24/2023] Open
Abstract
BACKGROUND Acinetobacter baumannii causes a wide range of dangerous infections due to the emergence of pandrug-resistant strains. Therefore, there is a need for alternative therapeutics to treat these infections, including those targeting the host immune responses. However, immune responses, especially the humoral response against this pathogen, are poorly understood. METHODS This study investigated the lymphocyte-mediated innate immune resistance to A. baumannii AB5075 pulmonary infection using B- and T-cell-deficient (Rag2-/-) mice, the protective effect of natural antibodies (NAbs), and the expression of complement-mediated responses using a mouse pneumonia model. RESULTS Our results showed that intranasally infected Rag2-/- mice are impaired in clearing bacteria from lung, liver, and spleen at 24 hours postinfection compared to wildtype mice. Animal pretreatment with normal mouse serum or purified antibodies from naive mice rescued Rag2-/- mice from infection. Analysis of C3 complement protein binding demonstrated that NAbs increased C3 protein deposition on A. baumannii cells, indicating the activation of the classical complement pathway by NAbs. CONCLUSIONS Overall, our study shows that NAbs mediate innate immune resistance against A. baumannii, a finding that may lead to the development of effective therapies against human infections caused by this antibiotic-resistant A. baumannii.
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Elbehiry A, Marzouk E, Moussa I, Mushayt Y, Algarni AA, Alrashed OA, Alghamdi KS, Almutairi NA, Anagreyyah SA, Alzahrani A, Almuzaini AM, Alzaben F, Alotaibi MA, Anjiria SA, Abu-Okail A, Abalkhail A. The Prevalence of Multidrug-Resistant Acinetobacter baumannii and Its Vaccination Status among Healthcare Providers. Vaccines (Basel) 2023; 11:1171. [PMID: 37514987 PMCID: PMC10384490 DOI: 10.3390/vaccines11071171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 06/21/2023] [Accepted: 06/22/2023] [Indexed: 07/30/2023] Open
Abstract
There is growing concern among healthcare providers worldwide regarding the prevalence of multidrug-resistant Acinetobacter baumannii (A. baumannii). Some of the worst hospital-acquired infections, often in intensive care units (ICUs), are caused by this bacterial pathogen. In recent years, the rise in multidrug-resistant A. baumannii has been linked to the overuse of antimicrobial drugs and the lack of adequate infection control measures. Infections caused by this bacterial pathogen are the result of prolonged hospitalization and ICU stays, and they are associated with increased morbidity and mortality. This review outlines the epidemiology, risk factors, and antimicrobial resistance associated with A. baumannii in various countries, with a special focus on the Kingdom of Saudi Arabia. In response to the growing concern regarding this drug-resistant bacteria, fundamental information about its pathology has been incorporated into the development of vaccines. Although these vaccines have been successful in animal models, their effectiveness in humans remains unproven. The review will discuss the development of A. baumannii vaccines, potential related obstacles, and efforts to find an effective strategy against this pathogen.
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Affiliation(s)
- Ayman Elbehiry
- Department of Public Health, College of Public Health and Health Informatics, Qassim University, Al Bukayriyah 52741, Saudi Arabia
- Department of Bacteriology, Mycology and Immunology, Faculty of Veterinary Medicine, University of Sadat City, Sadat City 32511, Egypt
| | - Eman Marzouk
- Department of Public Health, College of Public Health and Health Informatics, Qassim University, Al Bukayriyah 52741, Saudi Arabia
| | - Ihab Moussa
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
| | - Yazeed Mushayt
- Department of Support Service, King Fahad Armed Hospital, Jeddah 23311, Saudi Arabia
| | | | - Osama Ali Alrashed
- Family Medicine Department, King Fahad Armed Hospital, Jeddah 23311, Saudi Arabia
| | - Khalid Saad Alghamdi
- Family Medicine Department, King Fahad Armed Hospital, Jeddah 23311, Saudi Arabia
| | - Naif Ahmed Almutairi
- Family Medicine Department, King Fahad Armed Hospital, Jeddah 23311, Saudi Arabia
| | | | - Anwar Alzahrani
- Cardiac Center, King Fahad Armed Forces Hospital, Jeddah 23311, Saudi Arabia
| | - Abdulaziz M Almuzaini
- Department of Veterinary Medicine, College of Agriculture and Veterinary Medicine, Qassim University, Buraydah 52571, Saudi Arabia
| | - Feras Alzaben
- Department of Food Service, King Fahad Armed Hospital, Jeddah 23311, Saudi Arabia
| | | | | | - Akram Abu-Okail
- Department of Veterinary Medicine, College of Agriculture and Veterinary Medicine, Qassim University, Buraydah 52571, Saudi Arabia
| | - Adil Abalkhail
- Department of Public Health, College of Public Health and Health Informatics, Qassim University, Al Bukayriyah 52741, Saudi Arabia
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Higham SL, Baker S, Flight KE, Krishna A, Kellam P, Reece ST, Tregoning JS. Intranasal immunization with outer membrane vesicles (OMV) protects against airway colonization and systemic infection with Acinetobacter baumannii. J Infect 2023; 86:563-573. [PMID: 36858180 DOI: 10.1016/j.jinf.2023.02.035] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 02/08/2023] [Accepted: 02/23/2023] [Indexed: 03/02/2023]
Abstract
OBJECTIVES The multidrug-resistant bacteria Acinetobacter baumannii is a major cause of hospital-associated infection; a vaccine could significantly reduce this burden. The aim was to develop a clinically relevant model of A. baumannii respiratory tract infection and to test the impact of different immunization routes on protective immunity provided by an outer membrane vesicle (OMV) vaccine. METHODS BALB/c mice were intranasally challenged with isolates of oxa23-positive global clone GC2 A. baumannii from the lungs of patients with ventilator-associated pneumonia. Mice were immunized with OMVs by the intramuscular, subcutaneous or intranasal routes; protection was determined by measuring local and systemic bacterial load. RESULTS Infection with A. baumannii clinical isolates led to a more disseminated infection than the prototype A. baumannii strain ATCC17978; with bacteria detectable in upper and lower airways and the spleen. Intramuscular immunization induced an antibody response but did not protect against bacterial infection. However, intranasal immunization significantly reduced airway colonization and prevented systemic bacterial dissemination. CONCLUSIONS Use of clinically relevant isolates of A. baumannii provides stringent model for vaccine development. Intranasal immunization with OMVs was an effective route for providing protection, demonstrating that local immunity is important in preventing A. baumannii infection.
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Affiliation(s)
- Sophie L Higham
- Department of Infectious Disease, Imperial College London, St Marys Campus, Norfolk Place, London W2 1PG, United Kingdom
| | - Stephen Baker
- Cambridge Institute of Therapeutic Immunology & Infectious Disease, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Puddicombe Way, Cambridge CB2 0AW, United Kingdom
| | - Katie E Flight
- Department of Infectious Disease, Imperial College London, St Marys Campus, Norfolk Place, London W2 1PG, United Kingdom
| | - Aishwarya Krishna
- Infectious Diseases and Vaccines, Kymab, Babraham Research Campus, Cambridge CB22 3AT, United Kingdom
| | - Paul Kellam
- Department of Infectious Disease, Imperial College London, St Marys Campus, Norfolk Place, London W2 1PG, United Kingdom; Infectious Diseases and Vaccines, Kymab, Babraham Research Campus, Cambridge CB22 3AT, United Kingdom; RQ Biotechnology Ltd, 7-12 Tavistock Square, London WC1H 9LT, United Kingdom
| | - Stephen T Reece
- Infectious Diseases and Vaccines, Kymab, Babraham Research Campus, Cambridge CB22 3AT, United Kingdom.
| | - John S Tregoning
- Department of Infectious Disease, Imperial College London, St Marys Campus, Norfolk Place, London W2 1PG, United Kingdom.
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Piri-Gharaghie T, Doosti A, Mirzaei SA. Novel adjuvant nano-vaccine induced immune response against Acinetobacter baumannii. AMB Express 2023; 13:31. [PMID: 36905472 PMCID: PMC10008545 DOI: 10.1186/s13568-023-01531-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 02/21/2023] [Indexed: 03/12/2023] Open
Abstract
Developing adjuvant vaccines to combat rising multidrug-resistant (MDR) Acinetobacter baumannii (A. baumannii) infections is a promising and cost-effective approach. The aim of this analysis was to construct a pDNA-CPG C274-adjuvant nano-vaccine and investigate its immunogenicity and protection in BALB/c mice. The CPG ODN C274 adjuvant was chemically synthesized and cloned into pcDNA3.1( +), and the cloning was verified using PCR and BamHI/EcoRV restriction enzyme digestion. Then, utilizing a complex coacervation approach, pDNA-CPG C274 was encapsulated by chitosan (CS) nanoparticles (NPs). TEM and DLS are used to explore the properties of the pDNA/CSNP complex. TLR-9 pathway activation was investigated in human HEK-293 and RAW 264.7 mouse cells. The vaccine's immunogenicity and immune-protective effectiveness were investigated in BALB/c mice. The pDNA-CPG C274/CSNPs were small (mean size 79.21 ± 0.23 nm), positively charged (+ 38.87 mV), and appeared to be spherical. A continuous slow release pattern was achieved. TLR-9 activation was greatest in the mouse model with CpG ODN (C274) at concentrations of 5 and 10 μg/ml with 56% and 55%, respectively (**P < 0.01). However, in HEK-293 human cells, by increasing the concentration of CpG ODN (C274) from 1 to 50 μg/ml, the activation rate of TLR-9 also increased, so that the highest activation rate (81%) was obtained at the concentration of 50 μg/ml (***P < 0.001). pDNA-CPG C274/CSNPs immunized BALB/c mice produced increased amounts of total-IgG, as well as IFN-γ and IL-1B in serum samples, compared to non-encapsulated pDNA-CPG C274. Furthermore, liver and lung injuries, as well as bacterial loads in the liver, lung, and blood, were reduced, and BALB/c mice immunized with pDNA-CPG C274/CSNPs showed potent protection (50-75%) against acute fatal Intraperitoneal A. baumannii challenge. pDNA-CPG C274/CSNPs evoked total-IgG antibodies, Th1 cellular immunity, and the TLR-9 pathway, as well as protection against an acute fatal A. baumannii challenge. Our findings suggest that this nano-vaccine is a promising approach for avoiding A. baumannii infection when used as a powerful adjuvant.
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Affiliation(s)
- Tohid Piri-Gharaghie
- Department of Biology, Faculty of Basic Sciences, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran
| | - Abbas Doosti
- Biotechnology Research Center, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran.
| | - Seyed Abbas Mirzaei
- Department of Biology, Faculty of Basic Sciences, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran.,Cellular and Molecular Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Shahrekord, Iran
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Shadan A, Pathak A, Ma Y, Pathania R, Singh RP. Deciphering the virulence factors, regulation, and immune response to Acinetobacter baumannii infection. Front Cell Infect Microbiol 2023; 13:1053968. [PMID: 36968113 PMCID: PMC10038080 DOI: 10.3389/fcimb.2023.1053968] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 02/06/2023] [Indexed: 02/25/2023] Open
Abstract
Deciphering the virulence factors, regulation, and immune response to Acinetobacter baumannii infectionAcinetobacter baumannii is a gram-negative multidrug-resistant nosocomial pathogen and a major cause of hospital acquired infetions. Carbapenem resistant A. baumannii has been categorised as a Priority1 critial pathogen by the World Health Organisation. A. baumannii is responsible for infections in hospital settings, clinical sectors, ventilator-associated pneumonia, and bloodstream infections with a mortality rates up to 35%. With the development of advanced genome sequencing, molecular mechanisms of manipulating bacterial genomes, and animal infection studies, it has become more convenient to identify the factors that play a major role in A. baumannii infection and its persistence. In the present review, we have explored the mechanism of infection, virulence factors, and various other factors associated with the pathogenesis of this organism. Additionally, the role of the innate and adaptive immune response, and the current progress in the development of innovative strategies to combat this multidrug-resistant pathogen is also discussed.
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Affiliation(s)
- Afreen Shadan
- Department of Microbiology, Dr. Shyama Prasad Mukherjee University, Ranchi, Jharkhand, India
| | - Avik Pathak
- Department of Biosciences and Bioengineering, Indian Institute of Technology, Roorkee, India
| | - Ying Ma
- College of Resources and Environment, Southwest University, Chongqing, China
- *Correspondence: Ying Ma, ; Ranjana Pathania, ; Rajnish Prakash Singh,
| | - Ranjana Pathania
- Department of Biosciences and Bioengineering, Indian Institute of Technology, Roorkee, India
- *Correspondence: Ying Ma, ; Ranjana Pathania, ; Rajnish Prakash Singh,
| | - Rajnish Prakash Singh
- Department of Bioengineering and Biotechnology, Birla Institute of Technology, Ranchi, Jharkhand, India
- *Correspondence: Ying Ma, ; Ranjana Pathania, ; Rajnish Prakash Singh,
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9
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Distel JS, Di Venanzio G, Mackel JJ, Rosen DA, Feldman MF. Replicative Acinetobacter baumannii strains interfere with phagosomal maturation by modulating the vacuolar pH. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.02.526753. [PMID: 36778331 PMCID: PMC9915592 DOI: 10.1101/2023.02.02.526753] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Bacterial pneumonia is a common infection of the lower respiratory tract that can afflict patients of all ages. Multidrug-resistant strains of Acinetobacter baumannii are increasingly responsible for causing nosocomial pneumonias, thus posing an urgent threat. Alveolar macrophages play a critical role in overcoming respiratory infections caused by this pathogen. Recently, we and others have shown that new clinical isolates of A. baumannii , but not the common lab strain ATCC 19606 (19606), can persist and replicate in macrophages within spacious vacuoles that we called A cinetobacter C ontaining V acuoles (ACV). In this work, we demonstrate that the modern A. baumannii clinical isolate 398, but not the lab strain 19606, can infect alveolar macrophages and produce ACVs in vivo in a murine pneumonia model. Both strains initially interact with the alveolar macrophage endocytic pathway, as indicated by EEA1 and LAMP1 markers; however, the fate of these strains diverges at a later stage. While 19606 is eliminated in an autophagy pathway, 398 replicates in ACVs and are not degraded. We show that 398 reverts the natural acidification of the phagosome by secreting large amounts of ammonia, a by-product of amino acid catabolism. We propose that this ability to survive within macrophages may be critical for the persistence of clinical A. baumannii isolates in the lung during a respiratory infection.
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Affiliation(s)
- Jesus S. Distel
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Gisela Di Venanzio
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Joseph J. Mackel
- Department of Pediatrics, Division of Infectious Diseases, Washington University School of Medicine, Saint Louis, MO, United States
| | - David A Rosen
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, Missouri, United States of America.,Department of Pediatrics, Division of Infectious Diseases, Washington University School of Medicine, Saint Louis, MO, United States
| | - Mario F. Feldman
- Department of Molecular Microbiology, Washington University School of Medicine, Saint Louis, Missouri, United States of America.,Corresponding author: Mario F. Feldman,
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Fereshteh S, Ajdary S, Sepehr A, Bolourchi N, Barzi SM, Haririzadeh Jouriani F, Riazi-Rad F, Shahcheraghi F, Badmasti F. Immunization with recombinant DcaP-like protein and AbOmpA revealed protections against sepsis infection of multi-drug resistant Acinetobacter baumannii ST2 Pas in a C57BL/6 mouse model. Microb Pathog 2023; 174:105882. [PMID: 36403713 DOI: 10.1016/j.micpath.2022.105882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 11/11/2022] [Accepted: 11/11/2022] [Indexed: 11/18/2022]
Abstract
BACKGROUNDS The prevalence of infections associated with multi-drug resistant (MDR) Acinetobacter baumannii is increasing worldwide. Therefore, the introduction of effective vaccines against this bacterium seems necessary. METHODS AbOmpA and DcaP-like protein were selected as promising and putative immunogenic candidates based on previous in silico studies. Three formulations including AbOmpA, DcaP-like protein, and AbOmpA + DcaP-like protein were injected into C57BL/6 mice three times with Alum adjuvant. The specific production of IgG antibodies (e.g. total IgG, IgG1 and IgG2c) and cytokines (e.g. IL-4, IL-6, and IL-17A), were evaluated. LD50% of MDR A. baumannii ST2Pas was measured using Probit's method. After the challenge with bacteria, a decrease in bacterial loads (DLs) in the lung and spleen of mice was measured. Then serum bactericidal assay was performed to determine the function of antibodies on day 42. In addition, histopathological examinations of the spleen and lung, the number of macrophage and neutrophil, as well as the rate of lymphocyte infiltration were assessed. RESULTS The highest level of total IgG was reported in the group immunized with DcaP-like protein on day 42. The survival rate of mice was 80% in the AbOmpA immunized group and 100% for the rest of two groups. DLs in the spleen of mice immunized with AbOmpA, DcaP-like protein, and combination form were 3.5, 3, and 3.4 Log10 (CFU/g), respectively. While in the lung, the DLs were 7.5 Log10 (CFU/g) for the AbOmpA group and 5 for the rest of two groups. The levels of IL-6, IL-4, and IL-17A were significantly decreased in all immunized groups after the bacterial challenge (except for IL-17A in the group of AbOmpA). The bactericidal effect of antibodies against DcaP-like protein was more effective. No histopathological damage was observed in the combination immunized group. The DcaP-like protein was more effective in neutrophil and macrophage deployment and decreased lymphocyte infiltration. CONCLUSION The results of immunization with AbOmpA + DcaP-like protein induced a protective reaction against the sepsis infection of MDR A. baumannii. It seems that in the future, these proteins can be considered as promising components in the development of the A. baumannii vaccine.
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Affiliation(s)
| | - Soheila Ajdary
- Department of Immunology, Pasteur Institute of Iran, Tehran, Iran
| | - Amin Sepehr
- Department of Bacteriology, Pasteur Institute of Iran, Tehran, Iran
| | - Negin Bolourchi
- Department of Bacteriology, Pasteur Institute of Iran, Tehran, Iran
| | | | | | - Farhad Riazi-Rad
- Department of Immunology, Pasteur Institute of Iran, Tehran, Iran
| | | | - Farzad Badmasti
- Department of Bacteriology, Pasteur Institute of Iran, Tehran, Iran.
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Pseudomonas aeruginosa PAO1 outer membrane vesicles-diphtheria toxoid conjugate as a vaccine candidate in a murine burn model. Sci Rep 2022; 12:22324. [PMID: 36566282 PMCID: PMC9789887 DOI: 10.1038/s41598-022-26846-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 12/21/2022] [Indexed: 12/25/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen considered a common cause of nosocomial infection with high morbidity and mortality in burn patients. Immunoprophylaxis techniques may lower the mortality rate of patients with burn wounds infected by P. aeruginosa; consequently, this may be an efficient strategy to manage infections caused by this bacterium. Several pathogenic Gram-negative bacteria like P. aeruginosa release outer membrane vesicles (OMVs), and structurally OMV consists of several antigenic components capable of generating a wide range of immune responses. Here, we evaluated the immunogenicity and efficacy of P. aeruginosa PA-OMVs (PA-OMVs) conjugated with the diphtheria toxoid (DT) formulated with alum adjuvant (PA-OMVs-DT + adj) in a mice model of burn wound infection. ELISA results showed that in the group of mice immunized with PA-OMVs-DT + adj conjugated, there was a significant increase in specific antibodies titer compared to non-conjugated PA-OMVs or control groups. In addition, the vaccination of mice with PA-OMVs-DT + adj conjugated generated greater protective effectiveness, as seen by lower bacterial loads, and eightfold decreased inflammatory cell infiltration with less tissue damage in the mice burn model compared to the control group. The opsonophagocytic killing results confirmed that humoral immune response might be critical for PA-OMVs mediated protection. These findings suggest that PA-OMV-DT conjugated might be used as a new vaccine against P. aeruginosa in burn wound infection.
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12
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Nithichanon A, Kewcharoenwong C, Da-oh H, Surajinda S, Khongmee A, Koosakunwat S, Wren BW, Stabler RA, Brown JS, Lertmemongkolchai G. Acinetobacter nosocomialis Causes as Severe Disease as Acinetobacter baumannii in Northeast Thailand: Underestimated Role of A. nosocomialis in Infection. Microbiol Spectr 2022; 10:e0283622. [PMID: 36227120 PMCID: PMC9769887 DOI: 10.1128/spectrum.02836-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Accepted: 09/21/2022] [Indexed: 01/09/2023] Open
Abstract
Infections by Acinetobacter species are recognized as a serious global threat due to causing severe disease and their high levels of antibiotic resistance. Acinetobacter baumannii is the most prevalent pathogen in the genus, but infection by Acinetobacter nosocomialis has been reported widely. Diagnosis of patients with A. baumannii infection is often misdiagnosed with other Acinetobacter species, especially A. nosocomialis. This study investigated whether there were significant differences in clinical outcomes between patients infected with A. baumannii versus A. nosocomialis in Northeast Thailand, and to characterize serological responses to infection with these pathogens. The results show that A. baumannii had higher levels of multidrug resistance. Despite this, clinical outcomes for infection with A. baumannii or A. nosocomialis were similar with mortalities of 33% and 36%, respectively. Both pathogens caused community-acquired infections (A. baumannii 35% and A. nosocomialis 29% of cases). Plasma from uninfected healthy controls contained IgG antibody that recognized both organisms, and infected patients did not show a significantly enhanced antibody response from the first week versus 2 weeks later. Finally, the patterns of antigen recognition for plasma IgG were similar for patients infected with A. baumannii or A. nosocomialis infection, and distinct to the pattern for patients infected with non-Acinetobacter. In conclusion, our data revealed that infection with A. nosocomialis was associated with a similarly high level of mortality as infection with A. baumannii, the high rate of community-acquired infection and antibodies in uninfected individuals suggesting that there is significant community exposure to both pathogens. IMPORTANCE Bacterial infections by Acinetobacter species are global threats due to their severity and high levels of antibiotic resistance. A. baumannii is the most common pathogen in the genus; however, infection by A. nosocomialis has also been widely reported but is thought to be less severe. In this study, we have prospectively investigated 48 reported cases of A. baumannii infection in Northeast Thailand, and characterized the serological responses to infection. We found that 14 (29%) of these infections were actually caused by A. nosocomialis. Furthermore, the incidence of antibiotic resistance among A. nosocomialis strains, APACHE II scores, and mortality for patients infected with A. nosocomialis were much higher than published data. Both A. baumannii and A. nosocomialis had unexpectedly mortality rates of over 30%, and both pathogens caused a high rate of community-acquired infections. Importantly, background antibodies in uninfected individuals suggest significant community exposure to both pathogens in the environment.
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Affiliation(s)
- Arnone Nithichanon
- Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai, Thailand
- Research and Diagnostic Center for Emerging Infectious Diseases (RCEID), Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Chidchamai Kewcharoenwong
- Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai, Thailand
- Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | - Hudadini Da-oh
- Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai, Thailand
| | - Sirithorn Surajinda
- Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai, Thailand
| | - Aranya Khongmee
- Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
| | | | - Brendan W. Wren
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Infectious and Tropical Disease, London, United Kingdom
| | - Richard A. Stabler
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, Infectious and Tropical Disease, London, United Kingdom
| | - Jeremy S. Brown
- Centre for Inflammation and Tissue Repair, UCL Respiratory, London, United Kingdom
| | - Ganjana Lertmemongkolchai
- Department of Medical Technology, Faculty of Associated Medical Sciences, Chiang Mai University, Chiang Mai, Thailand
- Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand
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13
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Anti-inflammatory effects of NaB and NaPc in Acinetobacter baumannii-stimulated THP-1 cells via TLR-2/NF-κB/ROS/NLRP3 pathway. ACTA PHARMACEUTICA (ZAGREB, CROATIA) 2022; 72:615-628. [PMID: 36651366 DOI: 10.2478/acph-2022-0036] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/11/2022] [Indexed: 01/20/2023]
Abstract
This study evaluated the anti-inflammation effect of the three main short-chain fatty acids (SCFAs) on Acinetobacter baumannii-induced THP-1 cells. The three main SCFAs could inhibit A. baumannii-stimulated THP-1 cell NF-κB pathway activity and the expressions of NLRP3 inflamma-some and GSDMD, and increase autophagy. The three main SCFAs, especially the sodium butyrate (NaB), had the effect of down-regulation of ROS and TLR-2 expression in THP-1 cells. NaB and sodium propionate (NaPc), but not sodium acetate (NaAc), dramatically suppressed IL-1β and IFN-γ expression. The results indicated that NaB and NaPc could significantly inhibit the inflammation of THP-1 cells induced by A. baumannii, and the inhibitory effect was in the order of NaB > NaPc > NaAC. NaB and NaPc may inhibit inflammation through TLR-2/NF-κB/ROS/NLRP3 signaling pathway.
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Wang J, Yang L, Wang H, Wang L. Application of Microfluidic Chips in the Detection of Airborne Microorganisms. MICROMACHINES 2022; 13:1576. [PMID: 36295928 PMCID: PMC9611547 DOI: 10.3390/mi13101576] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Revised: 09/14/2022] [Accepted: 09/17/2022] [Indexed: 06/16/2023]
Abstract
The spread of microorganisms in the air, especially pathogenic microorganisms, seriously affects people's normal life. Therefore, the analysis and detection of airborne microorganisms is of great importance in environmental detection, disease prevention and biosafety. As an emerging technology with the advantages of integration, miniaturization and high efficiency, microfluidic chips are widely used in the detection of microorganisms in the environment, bringing development vitality to the detection of airborne microorganisms, and they have become a research highlight in the prevention and control of infectious diseases. Microfluidic chips can be used for the detection and analysis of bacteria, viruses and fungi in the air, mainly for the detection of Escherichia coli, Staphylococcus aureus, H1N1 virus, SARS-CoV-2 virus, Aspergillus niger, etc. The high sensitivity has great potential in practical detection. Here, we summarize the advances in the collection and detection of airborne microorganisms by microfluidic chips. The challenges and trends for the detection of airborne microorganisms by microfluidic chips was also discussed. These will support the role of microfluidic chips in the prevention and control of air pollution and major outbreaks.
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Affiliation(s)
- Jinpei Wang
- College of Medicine, Xi’an International University, Xi’an 710077, China
- Engineering Research Center of Personalized Anti-Aging Health Product Development and Transformation, Universities of Shaanxi Province, Xi’an 710077, China
- Applied Research Center for Life Science, Xi’an International University, Xi’an 710077, China
| | - Lixia Yang
- College of Medicine, Xi’an International University, Xi’an 710077, China
- Engineering Research Center of Personalized Anti-Aging Health Product Development and Transformation, Universities of Shaanxi Province, Xi’an 710077, China
- Applied Research Center for Life Science, Xi’an International University, Xi’an 710077, China
| | - Hanghui Wang
- College of Medicine, Xi’an International University, Xi’an 710077, China
- Xi’an International Medical Center Hospital, Xi’an 710100, China
| | - Lin Wang
- College of Medicine, Xi’an International University, Xi’an 710077, China
- Engineering Research Center of Personalized Anti-Aging Health Product Development and Transformation, Universities of Shaanxi Province, Xi’an 710077, China
- Applied Research Center for Life Science, Xi’an International University, Xi’an 710077, China
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15
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Sheldon JR, Himmel LE, Kunkle DE, Monteith AJ, Maloney KN, Skaar EP. Lipocalin-2 is an essential component of the innate immune response to Acinetobacter baumannii infection. PLoS Pathog 2022; 18:e1010809. [PMID: 36054235 PMCID: PMC9477428 DOI: 10.1371/journal.ppat.1010809] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 09/15/2022] [Accepted: 08/12/2022] [Indexed: 12/11/2022] Open
Abstract
Acinetobacter baumannii is an opportunistic pathogen and an emerging global health threat. Within healthcare settings, major presentations of A. baumannii include bloodstream infections and ventilator-associated pneumonia. The increased prevalence of ventilated patients during the COVID-19 pandemic has led to a rise in secondary bacterial pneumonia caused by multidrug resistant (MDR) A. baumannii. Additionally, due to its MDR status and the lack of antimicrobial drugs in the development pipeline, the World Health Organization has designated carbapenem-resistant A. baumannii to be its priority critical pathogen for the development of novel therapeutics. To better inform the design of new treatment options, a comprehensive understanding of how the host contains A. baumannii infection is required. Here, we investigate the innate immune response to A. baumannii by assessing the impact of infection on host gene expression using NanoString technology. The transcriptional profile observed in the A. baumannii infected host is characteristic of Gram-negative bacteremia and reveals expression patterns consistent with the induction of nutritional immunity, a process by which the host exploits the availability of essential nutrient metals to curtail bacterial proliferation. The gene encoding for lipocalin-2 (Lcn2), a siderophore sequestering protein, was the most highly upregulated during A. baumannii bacteremia, of the targets assessed, and corresponds to robust LCN2 expression in tissues. Lcn2-/- mice exhibited distinct organ-specific gene expression changes including increased transcription of genes involved in metal sequestration, such as S100A8 and S100A9, suggesting a potential compensatory mechanism to perturbed metal homeostasis. In vitro, LCN2 inhibits the iron-dependent growth of A. baumannii and induces iron-regulated gene expression. To elucidate the role of LCN2 in infection, WT and Lcn2-/- mice were infected with A. baumannii using both bacteremia and pneumonia models. LCN2 was not required to control bacterial growth during bacteremia but was protective against mortality. In contrast, during pneumonia Lcn2-/- mice had increased bacterial burdens in all organs evaluated, suggesting that LCN2 plays an important role in inhibiting the survival and dissemination of A. baumannii. The control of A. baumannii infection by LCN2 is likely multifactorial, and our results suggest that impairment of iron acquisition by the pathogen is a contributing factor. Modulation of LCN2 expression or modifying the structure of LCN2 to expand upon its ability to sequester siderophores may thus represent feasible avenues for therapeutic development against this pathogen. A lack of therapeutic options has prompted the World Health Organization to designate multidrug-resistant Acinetobacter baumannii as its priority critical pathogen for research into new treatment strategies. The mechanisms employed by A. baumannii to cause disease and the host tactics exercised to constrain infection are not fully understood. Here, we further characterize the innate immune response to A. baumannii infection. We identify nutritional immunity, a process where the availability of nutrient metals is exploited to restrain bacterial growth, as being induced during infection. The gene encoding for lipocalin-2 (Lcn2), a protein that can impede iron uptake by bacteria, is highly upregulated in infected mice, and corresponds to robust LCN2 detection in the tissues. We find that LCN2 is crucial to reducing mortality from A. baumannii bacteremia and inhibits dissemination of the pathogen during pneumonia. In wild-type and Lcn2-deficient mice, broader transcriptional profiling reveals expression patterns consistent with the known response to Gram-negative bacteremia. Although the role of LCN2 in infection is likely multifactorial, we find its antimicrobial effects are at least partly exerted by impairing iron acquisition by A. baumannii. Facets of nutritional immunity, such as LCN2, may be exploited as novel therapeutics in combating A. baumannii infection.
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Affiliation(s)
- Jessica R. Sheldon
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Lauren E. Himmel
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Dillon E. Kunkle
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Andrew J. Monteith
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - K. Nichole Maloney
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Eric P. Skaar
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- * E-mail:
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Gao CA, Morales-Nebreda L, Pickens CI. Gearing up for battle: Harnessing adaptive T cell immunity against gram-negative pneumonia. Front Cell Infect Microbiol 2022; 12:934671. [PMID: 36061870 PMCID: PMC9433749 DOI: 10.3389/fcimb.2022.934671] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 07/25/2022] [Indexed: 11/28/2022] Open
Abstract
Pneumonia is one of the leading causes of morbidity and mortality worldwide and Gram-negative bacteria are a major cause of severe pneumonia. Despite advances in diagnosis and treatment, the rise of multidrug-resistant organisms and hypervirulent strains demonstrates that there will continue to be challenges with traditional treatment strategies using antibiotics. Hence, an alternative approach is to focus on the disease tolerance components that mediate immune resistance and enhance tissue resilience. Adaptive immunity plays a pivotal role in modulating these processes, thus affecting the incidence and severity of pneumonia. In this review, we focus on the adaptive T cell responses to pneumonia induced by Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii. We highlight key factors in these responses that have potential for therapeutic targeting, as well as the gaps in current knowledge to be focused on in future work.
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Chaudhuri S, Rasooli I, Oskouei RH, Pishgahi M, Jahangir A, Andisi VF, Schryvers AB. Hybrid antigens expressing surface loops of BauA from Acinetobacter baumannii are capable of inducing protection against infection. Front Immunol 2022; 13:933445. [PMID: 36045685 PMCID: PMC9420935 DOI: 10.3389/fimmu.2022.933445] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 07/18/2022] [Indexed: 11/13/2022] Open
Abstract
Acinetobacter baumannii is a human bacterial pathogen of increasing concern in clinical settings due to the emergence of antibiotic resistant strains and the lack of effective therapeutics. Researchers have been exploring new treatment options such as novel drug candidates and vaccines to prevent severe infections and mortality. Bacterial surface antigens that are essential to A. baumannii for acquiring micronutrients (e.g. iron, zinc) from nutrient restricted environments are being considered as targets for vaccines or immunotherapy due to their crucial role for growth and pathogenesis in the human host. BauA, the outer membrane receptor for the siderophore acinetobactin was targeted for vaccine development in this study. Due to challenges in the commercial production of membrane proteins for vaccines, a novel hybrid antigen method developed by our group was used. Exposed loops of BauA were selected and displayed on a foreign scaffold to generate novel hybrid antigens designed to elicit an immune response against the native BauA protein. The potential epitopes were incorporated into a scaffold derived from the C-lobe of Neisseria meningitidis transferrin binding protein B (TbpB), named the loopless C-lobe (LCL). Hybrid proteins displaying three selected loops (5, 7 and 8) individually or in combination were designed and produced and evaluated in an A. baumannii murine sepsis model as vaccine antigens. Immunization with the recombinant BauA protein protected 100% of the mice while immunization with hybrid antigens displaying individual loops achieved between 50 and 100% protection. The LCL scaffold did not induce a protective immune response, enabling us to attribute the observed protection elicited by the hybrid antigens to the displayed loops. Notably, the mice immunized with the hybrid antigen displaying loop 7 were completely protected from infection. Taken together, these results suggest that our hybrid antigen approach is a viable method for generating novel vaccine antigens that target membrane surface proteins necessary for bacterial growth and pathogenesis and the loop 7 hybrid antigen can be a foundation for approaches to combat A. baumannii infections.
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Affiliation(s)
- Somshukla Chaudhuri
- Department of Microbiology, Immunology and Infectious Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Iraj Rasooli
- Department of Biology, Shahed University, Tehran, Iran
| | | | | | - Abolfazl Jahangir
- Applied Biotechnology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Vahid Farshchi Andisi
- Department of Microbiology, Immunology and Infectious Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Anthony B. Schryvers
- Department of Microbiology, Immunology and Infectious Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- *Correspondence: Anthony B. Schryvers,
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Tiku V, Kew C, Kofoed EM, Peng Y, Dikic I, Tan MW. Acinetobacter baumannii Secretes a Bioactive Lipid That Triggers Inflammatory Signaling and Cell Death. Front Microbiol 2022; 13:870101. [PMID: 35615509 PMCID: PMC9125205 DOI: 10.3389/fmicb.2022.870101] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Accepted: 03/28/2022] [Indexed: 11/13/2022] Open
Abstract
Acinetobacter baumannii is a highly pathogenic Gram-negative bacterium that causes severe infections with very high fatality rates. A. baumannii infection triggers innate as well as adaptive immunity, however, our understanding of the inflammatory factors secreted by A. baumannii that alarm the immune system remains limited. In this study, we report that the lab adapted and clinical strains of A. baumannii secrete an inflammatory bioactive factor which activates TLR2, leading to canonical IRAK4-dependent NF-κB signaling and production of pro-inflammatory cytokines interleukin (IL)-6 and IL-8 and activation of the inflammasome pathway causing pyroptotic cell death. Biochemical fractionation of the A. baumannii culture filtrate revealed the hydrophobic nature of the inflammatory factor. Concordantly, lipase treatment of the culture filtrate or TLR2 inhibition in macrophages abrogated NF-κB activation and cell death induction. Culture filtrates from the LPS- and lipoprotein-deficient A. baumannii mutants retain immuno-stimulatory properties suggesting that a lipid other than these known stimulatory molecules can trigger inflammation during A. baumannii infection. Our results reveal that A. baumannii secretes a previously unappreciated inflammatory bioactive lipid that activates multiple pro-inflammatory signaling pathways and induces cell death in human and murine macrophages.
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Affiliation(s)
- Varnesh Tiku
- Department of Infectious Diseases, Genentech, South San Francisco, CA, United States
- *Correspondence: Varnesh Tiku,
| | - Chun Kew
- Faculty of Medicine, Institute of Biochemistry II, Goethe University Frankfurt, Frankfurt, Germany
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany
| | - Eric M. Kofoed
- Department of Infectious Diseases, Genentech, South San Francisco, CA, United States
| | - Yutian Peng
- Department of Infectious Diseases, Genentech, South San Francisco, CA, United States
| | - Ivan Dikic
- Faculty of Medicine, Institute of Biochemistry II, Goethe University Frankfurt, Frankfurt, Germany
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt, Germany
- Max Planck Institute of Biophysics, Frankfurt, Germany
- Ivan Dikic,
| | - Man-Wah Tan
- Department of Infectious Diseases, Genentech, South San Francisco, CA, United States
- Man-Wah Tan,
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The Antimicrobial Peptide Esc(1-21) Synergizes with Colistin in Inhibiting the Growth and in Killing Multidrug Resistant Acinetobacter baumannii Strains. Antibiotics (Basel) 2022; 11:antibiotics11020234. [PMID: 35203836 PMCID: PMC8868345 DOI: 10.3390/antibiotics11020234] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 02/04/2022] [Accepted: 02/08/2022] [Indexed: 02/01/2023] Open
Abstract
Multidrug-resistant microbial infections and the scarce availability of new antibiotics capable of eradicating them are posing a serious problem to global health security. Among the microorganisms that easily acquire resistance to antibiotics and that are the etiological cause of severe infections, there is Acinetobacter baumannii. Carbapenems are the principal agents used to treat A. baumannii infections. However, when strains develop resistance to this class of antibiotics, colistin is considered one of the last-resort drugs. However, the appearance of resistance to colistin also makes treatment of the Acinetobacter infections very difficult. Antimicrobial peptides (AMP) from the innate immunity hold promise as new alternative antibiotics due to their multiple biological properties. In this study, we characterized the activity and the membrane-perturbing mechanism of bactericidal action of a derivative of a frog-skin AMP, namely Esc(1-21), when used alone or in combination with colistin against multidrug-resistant A. baumannii clinical isolates. We found that the mixture of the two compounds had a synergistic effect in inhibiting the growth and killing of all of the tested strains. When combined at dosages below the minimal inhibitory concentration, the two drugs were also able to slow down the microbial growth and to potentiate the membrane-perturbing effect. To the best of our knowledge, this is the first report showing a synergistic effect between AMPs, i.e., Esc(1-21), and colistin against colistin-resistant A. baumannii clinical isolates, highlighting the potential clinical application of such combinational therapy.
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Tansho-Nagakawa S, Sato Y, Ubagai T, Kikuchi-Ueda T, Kamoshida GO, Nishida S, Ono Y. Histopathological Analysis of Acinetobacter baumannii Lung Infection in a Mouse Model. Pol J Microbiol 2022; 70:469-477. [PMID: 35003278 PMCID: PMC8702610 DOI: 10.33073/pjm-2021-044] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 10/31/2021] [Indexed: 11/20/2022] Open
Abstract
Acinetobacter baumannii is the main causative pathogen of nosocomial infections that causes severe infections in the lungs. In this study, we analyzed the histopathological characteristics of lung infection with two strains of A. baumannii (ATCC 19606 and the clinical isolate TK1090) and Pseudomonas aeruginosa PAO-1 in C3H/HeN mice to evaluate the virulence of A. baumannii. Survival was evaluated over 14 days. At 1, 2, 5, or 14 days postinfection, mice of C3H/HeN were sacrificed, and histopathological analysis of lung specimens was also performed. Histopathological changes and accumulation of neutrophils and macrophages in the lungs after infection with A. baumannii and P. aeruginosa were analyzed. Following intratracheal inoculation, the lethality of ATCC 19606- and TK1090-infected mice was lower than that of PAO-1-infected mice. However, when mice were inoculated with a sub-lethal dose of A. baumannii, the lung bacterial burden remained in the mice until 14 days post-infection. Additionally, histopathological analysis revealed that macrophages infiltrated the lung foci of ATCC 19606-, TK1090-, and PAO-1-infected mice. Although neutrophils infiltrated the lung foci of ATCC 19606- and TK1090-infected mice, they poorly infiltrated the lung foci of PAO-1-infected mice. Accumulation of these cells in the lung foci of ATCC 19606- and TK1090-infected mice, but not PAO-1-infected mice, was observed for 14 days post-infection. These results suggest that A. baumannii is not completely eliminated despite the infiltration of immune cells in the lungs and that inflammation lasts for prolonged periods in the lungs. Further studies are required to understand the mechanism of A. baumannii infection, and novel drugs and vaccines should be developed to prevent A. baumannii infection.
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Affiliation(s)
- Shigeru Tansho-Nagakawa
- Department of Microbiology and Immunology, Teikyo University School of Medicine, Tokyo, Japan
| | - Yoshinori Sato
- Department of Microbiology and Immunology, Teikyo University School of Medicine, Tokyo, Japan
| | - Tsuneyuki Ubagai
- Department of Microbiology and Immunology, Teikyo University School of Medicine, Tokyo, Japan
| | - Takane Kikuchi-Ueda
- Department of Microbiology and Immunology, Teikyo University School of Medicine, Tokyo, Japan
| | - G O Kamoshida
- Department of Microbiology and Immunology, Teikyo University School of Medicine, Tokyo, Japan
| | - Satoshi Nishida
- Department of Microbiology and Immunology, Teikyo University School of Medicine, Tokyo, Japan
| | - Yasuo Ono
- Department of Microbiology and Immunology, Teikyo University School of Medicine, Tokyo, Japan
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Antimicrobial, Immunomodulatory and Anti-Inflammatory Potential of Liposomal Thymoquinone: Implications in the Treatment of Bacterial Pneumonia in Immunocompromised Mice. Biomedicines 2021; 9:biomedicines9111673. [PMID: 34829902 PMCID: PMC8615793 DOI: 10.3390/biomedicines9111673] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 11/08/2021] [Accepted: 11/09/2021] [Indexed: 11/17/2022] Open
Abstract
Acinetobacter baumannii has recently been increasing as an aggressive pathogen in immunocompromised persons. In the present study, we determined the in vitro antibacterial and anti-biofilm activity of thymoquinone (TQ) against A. baumannii. A liposomal formulation of TQ (Lip-TQ) was prepared and its therapeutic potential was investigated in the treatment of A. baumannii infection in immunocompromised mice. Leukopenia was induced in mice by injecting cyclophosphamide (CYP) at a dose of 200 mg/kg and the leukopenic mice were infected with 1 × 106 CFUs of A. baumannii. The effectiveness of free TQ or Lip-TQ against A. baumannii infection was assessed by analyzing the survival rate and bacterial burden. Moreover, the efficacy of Lip-TQ was also studied by examining the systemic inflammatory markers and the histological changes in the lung tissues. The results showed that the mice in the group treated with Lip-TQ at a dose of 10 mg/kg exhibited a 60% survival rate on day 40 post-infection, whereas all the mice treated with free TQ at the same dose died within this duration. Likewise, the lowest bacterial burden was found in the lung tissue of mice treated with Lip-TQ (10 mg/kg). Besides, Lip-TQ treatment remarkably alleviated the infection-associated inflammation, oxidative stress, and histological changes in the lung tissues. Based on the findings of the present study, we recommend considering Lip-TQ as a valuable therapeutic formulation in the treatment of A. baumannii-associated pneumonia in immunocompromised subjects.
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Yeganeh O, Shabani M, Pakzad P, Mosaffa N, Hashemi A. Production and characterization of novel monoclonal antibodies against outer membrane protein A (OmpA) of Acinetobacter baumannii. J Immunol Methods 2021; 499:113169. [PMID: 34666009 DOI: 10.1016/j.jim.2021.113169] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 09/10/2021] [Accepted: 10/11/2021] [Indexed: 11/17/2022]
Abstract
BACKGROUND Infection caused by Acinetobacter baumannii has emerged as a significant clinical problem with unacceptably high mortality rate due to the increase in antibiotic-resistant strains. Producing novel monoclonal antibody (MAb) against outer membrane protein A (OmpA) could be considered as a potential tool to improve treatment of A. baumannii infections. OBJECTIVES In this study, we aimed to produce murine MAbs against OmpA peptide of A. baumannii. MATERIALS AND METHODS BALB/c mice were immunized with 18-mer amino acid peptide as a part of the OmpA protein. Four antibody-secreting hybridomas were obtained using hybridoma technology and then characterized according to isotypes, affinity constant, reactivity in ELISA, flow cytometry, indirect immunofluorescence (IFA) and opsonophagocytic killing assays. RESULTS All four produced MAbs (1A1-D10, 1G1-E7, 2C11-F10, and 4H2-H9) had IgG1 isotype with Kappa light chain. One of these MAbs, 1G1-E7 was purified and selected for further characterizations. 1G1-E7 showed a high reactivity with both immunogenic peptide and A. baumannii in ELISA. Our results indicated that 1G1-E7 MAb reacted with 95.3% of A. baumannii in flow cytometry as well as IFA. Moreover, the affinity of the 1G1-E7 MAb was measured 1.37 × 108 M-1. The 1G1-E7 significantly improved opsonophagocytic killing of a clinical isolate of A. baumannii. CONCLUSION Our findings showed that the OmpA can be identified by produced MAbs. The efficacy of novel anti-OmpA antibodies in A. baumannii targeting needs to be further investigated in challenging models, and then could be subjected for genetic engineering to produce therapeutic antibody against A. baumannii.
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Affiliation(s)
- Omid Yeganeh
- Department of Microbiology, North Tehran Branch, Islamic Azad University, Tehran, Iran
| | - Mahdi Shabani
- Department of Immunology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Parviz Pakzad
- Department of Microbiology, North Tehran Branch, Islamic Azad University, Tehran, Iran
| | - Nariman Mosaffa
- Department of Immunology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Ali Hashemi
- Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Woo K, Kim DH, Oh MH, Park HS, Choi CH. N-3-Hydroxy Dodecanoyl-DL-homoserine Lactone (OH-dDHL) Triggers Apoptosis of Bone Marrow-Derived Macrophages through the ER- and Mitochondria-Mediated Pathways. Int J Mol Sci 2021; 22:ijms22147565. [PMID: 34299184 PMCID: PMC8305837 DOI: 10.3390/ijms22147565] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 07/11/2021] [Accepted: 07/13/2021] [Indexed: 02/06/2023] Open
Abstract
Quorum sensing of Acinetobacter nosocomialis for cell-to-cell communication produces N-3-hydroxy dodecanoyl-DL-homoserine lactone (OH-dDHL) by an AnoR/I two-component system. However, OH-dDHL-driven apoptotic mechanisms in hosts have not been clearly defined. Here, we investigated the induction of apoptosis signaling pathways in bone marrow-derived macrophages treated with synthetic OH-dDHL. Moreover, the quorum-sensing system for virulence regulation was evaluated in vivo using wild-type and anoI-deletion mutant strains. OH-dDHL decreased the viability of macrophage and epithelial cells in dose- and time-dependent manners. OH-dDHL induced Ca2+ efflux and caspase-12 activation by ER stress transmembrane protein (IRE1 and ATF6a p50) aggregation and induced mitochondrial dysfunction through reactive oxygen species (ROS) production, which caused cytochrome c to leak. Pretreatment with a pan-caspase inhibitor reduced caspase-3, -8, and -9, which were activated by OH-dDHL. Pro-inflammatory cytokine and paraoxonase-2 (PON2) gene expression were increased by OH-dDHL. We showed that the anoI-deletion mutant strains have less intracellular invasion compared to the wild-type strain, and their virulence, such as colonization and dissemination, was decreased in vivo. Consequently, these findings revealed that OH-dDHL, as a virulence factor, contributes to bacterial infection and survival as well as the modification of host responses in the early stages of infection.
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Affiliation(s)
- Kyungho Woo
- Department of Microbiology and Medical Science, Chungnam National University School of Medicine, Daejeon 35015, Korea; (K.W.); (D.H.K.); (H.S.P.)
| | - Dong Ho Kim
- Department of Microbiology and Medical Science, Chungnam National University School of Medicine, Daejeon 35015, Korea; (K.W.); (D.H.K.); (H.S.P.)
| | - Man Hwan Oh
- Department of Microbiology, Dankook University, Cheonan 31116, Korea;
| | - Ho Sung Park
- Department of Microbiology and Medical Science, Chungnam National University School of Medicine, Daejeon 35015, Korea; (K.W.); (D.H.K.); (H.S.P.)
| | - Chul Hee Choi
- Department of Microbiology and Medical Science, Chungnam National University School of Medicine, Daejeon 35015, Korea; (K.W.); (D.H.K.); (H.S.P.)
- Correspondence: ; Tel.: +82-42-580-8246
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Ma C, McClean S. Mapping Global Prevalence of Acinetobacter baumannii and Recent Vaccine Development to Tackle It. Vaccines (Basel) 2021; 9:vaccines9060570. [PMID: 34205838 PMCID: PMC8226933 DOI: 10.3390/vaccines9060570] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 05/16/2021] [Accepted: 05/22/2021] [Indexed: 12/23/2022] Open
Abstract
Acinetobacter baumannii is a leading cause of nosocomial infections that severely threaten public health. The formidable adaptability and resistance of this opportunistic pathogen have hampered the development of antimicrobial therapies which consequently leads to very limited treatment options. We mapped the global prevalence of multidrug-resistant A. baumannii and showed that carbapenem-resistant A. baumannii is widespread throughout Asia and the Americas. Moreover, when antimicrobial resistance rates of Acinetobacter spp. exceed a threshold level, the proportion of A. baumannii isolates from clinical samples surges. Therefore, vaccines represent a realistic alternative strategy to tackle this pathogen. Research into anti-A. baumannii vaccines have enhanced in the past decade and multiple antigens have been investigated preclinically with varying results. This review summarises the current knowledge of virulence factors relating to A. baumannii–host interactions and its implication in vaccine design, with a view to understanding the current state of A. baumannii vaccine development and the direction of future efforts.
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Li X, Liu X, Horvatovich P, Hu Y, Zhang J. Proteomics Landscape of Host-Pathogen Interaction in Acinetobacter baumannii Infected Mouse Lung. Front Genet 2021; 12:563516. [PMID: 34025711 PMCID: PMC8138179 DOI: 10.3389/fgene.2021.563516] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 04/14/2021] [Indexed: 12/15/2022] Open
Abstract
Acinetobacter baumannii is an important pathogen of nosocomial infection worldwide, which can primarily cause pneumonia, bloodstream infection, and urinary tract infection. The increasing drug resistance rate of A. baumannii and the slow development of new antibacterial drugs brought great challenges for clinical treatment. Host immunity is crucial to the defense of A. baumannii infection, and understanding the mechanisms of immune response can facilitate the development of new therapeutic strategies. To characterize the system-level changes of host proteome in immune response, we used tandem mass tag (TMT) labeling quantitative proteomics to compare the proteome changes of lungs from A. baumannii infected mice with control mice 6 h after infection. A total of 6,218 proteins were identified in which 6,172 could be quantified. With threshold p < 0.05 and relative expression fold change > 1.2 or < 0.83, we found 120 differentially expressed proteins. Bioinformatics analysis showed that differentially expressed proteins after infection were associated with receptor recognition, NADPH oxidase (NOX) activation and antimicrobial peptides. These differentially expressed proteins were involved in the pathways including leukocyte transendothelial migration, phagocyte, neutrophil degranulation, and antimicrobial peptides. In conclusion, our study showed proteome changes in mouse lung tissue due to A. baumannii infection and suggested the important roles of NOX, neutrophils, and antimicrobial peptides in host response. Our results provide a potential list of protein candidates for the further study of host-bacteria interaction in A. baumannii infection. Data are available via ProteomeXchange with identifier PXD020640.
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Affiliation(s)
- Xin Li
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China.,Key Laboratory of Clinical Pharmacology of Antibiotics, National Health and Family Planning Commission, Shanghai, China.,National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Xiaofen Liu
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China.,Key Laboratory of Clinical Pharmacology of Antibiotics, National Health and Family Planning Commission, Shanghai, China.,National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Peter Horvatovich
- Department of Analytical Biochemistry, Groningen Research Institute of Pharmacy, University of Groningen, Groningen, Netherlands
| | - Yingwei Hu
- Department of Pathology, Johns Hopkins University, Baltimore, MD, United States
| | - Jing Zhang
- Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, China.,Key Laboratory of Clinical Pharmacology of Antibiotics, National Health and Family Planning Commission, Shanghai, China.,National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
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Acinetobacter baumannii: An Ancient Commensal with Weapons of a Pathogen. Pathogens 2021; 10:pathogens10040387. [PMID: 33804894 PMCID: PMC8063835 DOI: 10.3390/pathogens10040387] [Citation(s) in RCA: 80] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 03/19/2021] [Accepted: 03/23/2021] [Indexed: 12/22/2022] Open
Abstract
Acinetobacter baumannii is regarded as a life-threatening pathogen associated with community-acquired and nosocomial infections, mainly pneumonia. The rise in the number of A. baumannii antibiotic-resistant strains reduces effective therapies and increases mortality. Bacterial comparative genomic studies have unraveled the innate and acquired virulence factors of A. baumannii. These virulence factors are involved in antibiotic resistance, environmental persistence, host-pathogen interactions, and immune evasion. Studies on host–pathogen interactions revealed that A. baumannii evolved different mechanisms to adhere to in order to invade host respiratory cells as well as evade the host immune system. In this review, we discuss current data on A. baumannii genetic features and virulence factors. An emphasis is given to the players in host–pathogen interaction in the respiratory tract. In addition, we report recent investigations into host defense systems using in vitro and in vivo models, providing new insights into the innate immune response to A. baumannii infections. Increasing our knowledge of A. baumannii pathogenesis may help the development of novel therapeutic strategies based on anti-adhesive, anti-virulence, and anti-cell to cell signaling pathways drugs.
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Efficacy of Lysophosphatidylcholine as Direct Treatment in Combination with Colistin against Acinetobacter baumannii in Murine Severe Infections Models. Antibiotics (Basel) 2021; 10:antibiotics10020194. [PMID: 33671416 PMCID: PMC7922394 DOI: 10.3390/antibiotics10020194] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/10/2021] [Accepted: 02/13/2021] [Indexed: 01/28/2023] Open
Abstract
The stimulation of the immune response to prevent the progression of an infection may be an adjuvant to antimicrobial treatment. Here, we aimed to evaluate the efficacy of lysophosphatidylcholine (LPC) treatment in combination with colistin in murine experimental models of severe infections by Acinetobacter baumannii. We used the A. baumannii Ab9 strain, susceptible to colistin and most of the antibiotics used in clinical settings, and the A. baumannii Ab186 strain, susceptible to colistin but presenting a multidrug-resistant (MDR) pattern. The therapeutic efficacies of one and two LPC doses (25 mg/kg/d) and colistin (20 mg/kg/8 h), alone or in combination, were assessed against Ab9 and Ab186 in murine peritoneal sepsis and pneumonia models. One and two LPC doses combined with colistin and colistin monotherapy enhanced Ab9 and Ab186 clearance from spleen, lungs and blood and reduced mice mortality compared with those of the non-treated mice group in both experimental models. Moreover, one and two LPC doses reduced the bacterial concentration in tissues and blood in both models and increased mice survival in the peritoneal sepsis model for both strains compared with those of the colistin monotherapy group. LPC used as an adjuvant of colistin treatment may be helpful to reduce the severity and the resolution of the MDR A. baumannii infection.
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Li Y, Peng C, Zhao D, Liu L, Guo B, Shi M, Xiao Y, Yu Z, Yu Y, Sun B, Wang W, Lin J, Yang X, Shao S, Zhang X. Outer membrane protein A inhibits the degradation of caspase-1 to regulate NLRP3 inflammasome activation and exacerbate the Acinetobacter baumannii pulmonary inflammation. Microb Pathog 2021; 153:104788. [PMID: 33571624 DOI: 10.1016/j.micpath.2021.104788] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 12/29/2020] [Accepted: 01/31/2021] [Indexed: 12/16/2022]
Abstract
Acinetobacter baumannii (A. baumannii), one of the major pathogens that causes severe nosocomial infections, is characterised by a high prevalence of drug resistance. It has been reported that A. baumannii triggers the NOD-like receptor 3 (NLRP3) inflammasome, but the role of its virulence-related outer membrane protein A (ompA) remains unclear. Therefore, this study aimed to explore the effects of ompA on the NLRP3 inflammasome and its underlying molecular mechanisms. Results showed that ompA enhanced inflammatory damage, which was reduced as a result of knockout of the ompA gene. Additionally, ompA-stimulated expression of NLRP3 inflammasome was significantly blocked by silencing caspase-1, but activation of NLRP3 inflammasome was not altered after silencing ASC; this indicated that ompA was dependent on the caspase-1 pathway to activate the inflammatory response. Simultaneously, the wild-type (WT) strains triggered NLRP3 inflammasome after inhibition of caspase-1 degradation by proteasome inhibitor MG-132, aggravating tissue damage. These findings indicated that ompA may be dependent on the caspase-1 pathway to enhance inflammation and exacerbate tissue damage. Taken together, these results confirmed a novel capsase-1-modulated mechanism underpinning ompA activity, which further reveals the NLRP3 inflammasome pathway as a potential immunomodulatory target against A. baumannii infections.
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Affiliation(s)
- Yumei Li
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Respiratory and Critical Medicine, Guizhou Provincial People's Hospital, Guiyang, Guizhou, 550025, China
| | - Chunhong Peng
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Respiratory and Critical Medicine, Guizhou Provincial People's Hospital, Guiyang, Guizhou, 550025, China
| | - Dan Zhao
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Respiratory and Critical Medicine, Guizhou Provincial People's Hospital, Guiyang, Guizhou, 550025, China
| | - Laibing Liu
- Department of Neurosurgery, Affiliated Baiyun Hospital, Guizhou Medical University, Guiyang, Guizhou, 550004, China
| | - Bing Guo
- Guizhou Provincial Key Laboratory of Pathogenesis and Drug Research on Common Chronic Diseases, Guizhou Medical University, Guiyang, Guizhou, 550025, China
| | - Mingjun Shi
- Guizhou Provincial Key Laboratory of Pathogenesis and Drug Research on Common Chronic Diseases, Guizhou Medical University, Guiyang, Guizhou, 550025, China
| | - Ying Xiao
- Guizhou Provincial Key Laboratory of Pathogenesis and Drug Research on Common Chronic Diseases, Guizhou Medical University, Guiyang, Guizhou, 550025, China
| | - Zijiang Yu
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Respiratory and Critical Medicine, Guizhou Provincial People's Hospital, Guiyang, Guizhou, 550025, China
| | - Yan Yu
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Respiratory and Critical Medicine, Guizhou Provincial People's Hospital, Guiyang, Guizhou, 550025, China
| | - Baofei Sun
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Respiratory and Critical Medicine, Guizhou Provincial People's Hospital, Guiyang, Guizhou, 550025, China; Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Guiyang, Guizhou, 550025, China
| | - Wenjuan Wang
- Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Guiyang, Guizhou, 550025, China
| | - Jieru Lin
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Respiratory and Critical Medicine, Guizhou Provincial People's Hospital, Guiyang, Guizhou, 550025, China
| | - Xiaoyan Yang
- Department of Pediatrics, Affiliated Hospital of Guizhou Medical University, Guiyang, Guizhou, 550004, China
| | - Songjun Shao
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Respiratory and Critical Medicine, Guizhou Provincial People's Hospital, Guiyang, Guizhou, 550025, China
| | - Xiangyan Zhang
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Respiratory and Critical Medicine, Guizhou Provincial People's Hospital, Guiyang, Guizhou, 550025, China.
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Susceptibility Testing of Colistin for Acinetobacter baumannii: How Far Are We from the Truth? Antibiotics (Basel) 2021; 10:antibiotics10010048. [PMID: 33466515 PMCID: PMC7824894 DOI: 10.3390/antibiotics10010048] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 12/07/2020] [Accepted: 12/31/2020] [Indexed: 12/22/2022] Open
Abstract
Acinetobacter baumannii is involved in life-threatening nosocomial infections, mainly in the intensive care units (ICUs), and often colistin may represent the last therapeutic opportunity. The susceptibility to colistin of 51 epidemiologically typed A. baumannii strains isolated in 2017 from clinical samples of patients hospitalized in the ICU of a tertiary care academic hospital was investigated. All isolates were carbapenem-resistant due to the presence of the blaOXA-23 gene in sequence group 1 (international clonal lineage II) and sequence group 4 (related to international clonal lineage II) isolates, and to the blaOXA-24/40 gene in sequence group 2 (international clonal lineage I) isolates. Vitek®2, agar diffusion, and broth microdilution tests showed major discordancy (≥2 dilution factors) in the minimum inhibitory concentration (MIC) values for colistin in 24 out of 51 isolates, resulting in erroneous reporting of qualitative susceptibility data for eight isolates. In growth kinetics experiments in the presence of colistin, five isolates grew with drug concentrations above the susceptibility breakpoint when incubated for >12 h, and three isolates showed the presence of heteroresistant subpopulations. This study highlights that the high frequency of isolation of carbapenem-resistant A. baumannii strains in high-risk infectious wards requires an accurate application of methods for detecting susceptibility to antibiotics, in particular to colistin, so as to ensure a correct therapeutic approach.
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Yan Q, Hao S, Shi F, Zou Y, Song X, Li L, Li Y, Guo H, He R, Zhao L, Ye G, Tang H. Epigallocatechin-3-gallate reduces liver and immune system damage in Acinetobacter baumannii-loaded mice with restraint stress. Int Immunopharmacol 2021; 92:107346. [PMID: 33412390 DOI: 10.1016/j.intimp.2020.107346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 12/08/2020] [Accepted: 12/25/2020] [Indexed: 11/28/2022]
Abstract
AIM Due to the significant increase in the antimicrobial resistance of Acinetobacter baumannii (A. baumannii), new drugs to block the progression of infection are strongly needed. Epigallocatechin-3-gallate (EGCG), a major component of green tea, has exhibited potential activity against A. baumannii in vitro. The aim of this study was to determine if EGCG could be used for pretreating stress-related effects, liver damage, and immune dysfunction caused by A. baumannii infection in vivo. METHODS Levels of stress hormones, oxidative stress, liver damage, and immune components were analyzed in a murine infection model in which the mice were pretreated with EGCG for one week then intranasally inoculated with A. baumannii. The mice were restrained for 12 h to promote infection because A. baumannii is an opportunistic pathogen. The pretreatment efficacy of EGCG against A. baumannii in mice was assessed for 24 h after the bacterial infection. RESULTS Restraint stress strengthened the damage from the A. baumannii infection. Pretreatment with EGCG in the murine pneumonia model markedly reduced stress hormones, oxidative metabolites, and proinflammatory cytokine production. EGCG also increased the immune function by increasing the levels of sIgA, T cells and neutrophils after infection. Moreover, pretreatment with EGCG significantly decreased the liver damage by inhibiting the levels of transaminases, oxidative stress metabolites, and cytokines, while maintaining the normal activity of CYP450 enzymes in the liver. CONCLUSION EGCG was efficacious as a preventative treatment for the damage seen in an experimental model of A. baumannii infection.
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Affiliation(s)
- Qiaohua Yan
- Department of Pharmacy, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China
| | - Suqi Hao
- Department of Pharmacy, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China
| | - Fei Shi
- Department of Pharmacy, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China
| | - Yuanfeng Zou
- Department of Pharmacy, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China
| | - Xu Song
- Department of Pharmacy, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China
| | - Lixia Li
- Department of Pharmacy, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China
| | - Yinglun Li
- Department of Pharmacy, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China
| | - Hongrui Guo
- Department of Pharmacy, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China
| | - Ran He
- Department of Pharmacy, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China
| | - Ling Zhao
- Department of Pharmacy, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China
| | - Gang Ye
- Department of Pharmacy, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China
| | - Huaqiao Tang
- Department of Pharmacy, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China.
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Evaluating the antimicrobial resistance and frequency of AmpC β-lactamases bla gene in Gram-negative bacteria isolates collected from selected hospitals of Iran: A multicenter retrospective study. GENE REPORTS 2020. [DOI: 10.1016/j.genrep.2020.100868] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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32
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Chen W. Host Innate Immune Responses to Acinetobacter baumannii Infection. Front Cell Infect Microbiol 2020; 10:486. [PMID: 33042864 PMCID: PMC7521131 DOI: 10.3389/fcimb.2020.00486] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Accepted: 08/05/2020] [Indexed: 12/23/2022] Open
Abstract
Acinetobacter baumannii has emerged as a major threat to global public health and is one of the key human pathogens in healthcare (nosocomial and community-acquired)-associated infections. Moreover, A. baumannii rapidly develops resistance to multiple antibiotics and is now globally regarded as a serious multidrug resistant pathogen. There is an urgent need to develop novel vaccines and immunotherapeutics as alternatives to antibiotics for clinical management of A. baumannii infection. However, our knowledge of host immune responses to A. baumannii infection and the identification of novel therapeutic targets are significantly lacking. This review highlights the recent advances and critical gaps in our understanding how A. baumannii interacts with the host innate pattern-recognition receptors, induces a cascade of inflammatory cytokine and chemokine responses, and recruits innate immune effectors (such as neutrophils and macrophages) to the site of infection for effective control of the infection. Such knowledge will facilitate the identification of new targets for the design and development of effective therapeutics and vaccines to fight this emerging threat.
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Affiliation(s)
- Wangxue Chen
- Human Health and Therapeutics (HHT) Research Center, National Research Council Canada, Ottawa, ON, Canada.,Department of Biology, Brock University, St. Catharines, ON, Canada
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Monem S, Furmanek-Blaszk B, Łupkowska A, Kuczyńska-Wiśnik D, Stojowska-Swędrzyńska K, Laskowska E. Mechanisms Protecting Acinetobacter baumannii against Multiple Stresses Triggered by the Host Immune Response, Antibiotics and Outside-Host Environment. Int J Mol Sci 2020; 21:E5498. [PMID: 32752093 PMCID: PMC7432025 DOI: 10.3390/ijms21155498] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/29/2020] [Accepted: 07/30/2020] [Indexed: 02/06/2023] Open
Abstract
Acinetobacter baumannii is considered one of the most persistent pathogens responsible for nosocomial infections. Due to the emergence of multidrug resistant strains, as well as high morbidity and mortality caused by this pathogen, A. baumannii was placed on the World Health Organization (WHO) drug-resistant bacteria and antimicrobial resistance research priority list. This review summarizes current studies on mechanisms that protect A. baumannii against multiple stresses caused by the host immune response, outside host environment, and antibiotic treatment. We particularly focus on the ability of A. baumannii to survive long-term desiccation on abiotic surfaces and the population heterogeneity in A. baumannii biofilms. Insight into these protective mechanisms may provide clues for the development of new strategies to fight multidrug resistant strains of A. baumannii.
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Affiliation(s)
- Soroosh Monem
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland; (S.M.); (A.Ł.); (D.K.-W.); (K.S.-S.)
| | - Beata Furmanek-Blaszk
- Department of Microbiology, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland;
| | - Adrianna Łupkowska
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland; (S.M.); (A.Ł.); (D.K.-W.); (K.S.-S.)
| | - Dorota Kuczyńska-Wiśnik
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland; (S.M.); (A.Ł.); (D.K.-W.); (K.S.-S.)
| | - Karolina Stojowska-Swędrzyńska
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland; (S.M.); (A.Ł.); (D.K.-W.); (K.S.-S.)
| | - Ewa Laskowska
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland; (S.M.); (A.Ł.); (D.K.-W.); (K.S.-S.)
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34
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Chen W. Host-pathogen interactions in Acinetobacter baumannii infection: recent advances and future challenges. Future Microbiol 2020; 15:841-845. [PMID: 32657617 DOI: 10.2217/fmb-2020-0032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Affiliation(s)
- Wangxue Chen
- National Research Council Canada, Human Health & Therapeutics (HHT) Research Center, 100 Sussex Drive, Ottawa, ON, K1A 0R6, Canada.,Department of Biology, Brock University, St. Catharines, ON, L2S 3A1, Canada
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35
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Li S, Chen DQ, Ji L, Sun S, Jin Z, Jin ZL, Sun HW, Zeng H, Zhang WJ, Lu DS, Luo P, Zhao AN, Luo J, Zou QM, Li HB. Development of Different Methods for Preparing Acinetobacter baumannii Outer Membrane Vesicles Vaccine: Impact of Preparation Method on Protective Efficacy. Front Immunol 2020; 11:1069. [PMID: 32655550 PMCID: PMC7324643 DOI: 10.3389/fimmu.2020.01069] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Accepted: 05/04/2020] [Indexed: 12/27/2022] Open
Abstract
Acinetobacter baumannii (A. baumannii) is becoming a common global concern due to the emergence of multi-drug or pan-drug resistant strains. Confronting the issue of antimicrobial resistance by developing vaccines against the resistant pathogen is becoming a common strategy. In this study, different methods for preparing A. baumannii outer membrane vesicles (AbOMVs) vaccines were developed. sOMV (spontaneously released AbOMV) was extracted from the culture supernatant, while SuOMV (sucrose-extracted AbOMV) and nOMV (native AbOMV) were prepared from the bacterial cells. Three AbOMVs exhibited significant differences in yield, particle size, protein composition, and LPS/DNA content. To compare the protective efficacy of the three AbOMVs, groups of mice were immunized either intramuscularly or intranasally with each AbOMV. Vaccination via both routes conferred significant protection against lethal and sub-lethal A. baumannii challenge. Moreover, intranasal vaccination provided more robust protection, which may be attributed to the induction of significant sIgA response in mucosal sites. Among the three AbOMVs, SuOMV elicited the highest level of protective immunity against A. baumannii infection, whether intramuscular or intranasal immunization, which was characterized by the expression of the most profound specific serum IgG or mucosal sIgA. Taken together, the preparation method had a significant effect on the yield, morphology, and composition of AbOMVs, that further influenced the protective effect against A. baumannii infection.
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Affiliation(s)
- Sun Li
- Department of Microbiology and Biochemical Pharmacy, National Engineering Research Center of Immunological Products, College of Pharmacy, Third Military Medical University, Chongqing, China
| | - Da-Qun Chen
- Department of Microbiology and Biochemical Pharmacy, National Engineering Research Center of Immunological Products, College of Pharmacy, Third Military Medical University, Chongqing, China
| | - Lu Ji
- Department of Microbiology and Biochemical Pharmacy, National Engineering Research Center of Immunological Products, College of Pharmacy, Third Military Medical University, Chongqing, China
| | - Si Sun
- Department of Microbiology and Biochemical Pharmacy, National Engineering Research Center of Immunological Products, College of Pharmacy, Third Military Medical University, Chongqing, China
| | - Zhe Jin
- Department of Microbiology and Biochemical Pharmacy, National Engineering Research Center of Immunological Products, College of Pharmacy, Third Military Medical University, Chongqing, China
| | - Zi-Li Jin
- Department of Microbiology and Biochemical Pharmacy, National Engineering Research Center of Immunological Products, College of Pharmacy, Third Military Medical University, Chongqing, China
| | - Hong-Wu Sun
- Department of Microbiology and Biochemical Pharmacy, National Engineering Research Center of Immunological Products, College of Pharmacy, Third Military Medical University, Chongqing, China
| | - Hao Zeng
- Department of Microbiology and Biochemical Pharmacy, National Engineering Research Center of Immunological Products, College of Pharmacy, Third Military Medical University, Chongqing, China
| | - Wei-Jun Zhang
- Department of Microbiology and Biochemical Pharmacy, National Engineering Research Center of Immunological Products, College of Pharmacy, Third Military Medical University, Chongqing, China
| | - Dong-Shui Lu
- Department of Microbiology and Biochemical Pharmacy, National Engineering Research Center of Immunological Products, College of Pharmacy, Third Military Medical University, Chongqing, China
| | - Ping Luo
- Department of Microbiology and Biochemical Pharmacy, National Engineering Research Center of Immunological Products, College of Pharmacy, Third Military Medical University, Chongqing, China
| | - An-Ni Zhao
- Department of Microbiology and Biochemical Pharmacy, National Engineering Research Center of Immunological Products, College of Pharmacy, Third Military Medical University, Chongqing, China
| | - Jiao Luo
- Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, Netherlands
| | - Quan-Ming Zou
- Department of Microbiology and Biochemical Pharmacy, National Engineering Research Center of Immunological Products, College of Pharmacy, Third Military Medical University, Chongqing, China
| | - Hai-Bo Li
- Department of Microbiology and Biochemical Pharmacy, National Engineering Research Center of Immunological Products, College of Pharmacy, Third Military Medical University, Chongqing, China
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36
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Chang YY, Yang YS, Wu SL, Wang YC, Chen TL, Lee YT. Comparison of Cefepime-Cefpirome and Carbapenem Therapy for Acinetobacter Bloodstream Infection in a Multicenter Study. Antimicrob Agents Chemother 2020; 64:e02392-19. [PMID: 32179523 PMCID: PMC7269511 DOI: 10.1128/aac.02392-19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 03/08/2020] [Indexed: 11/20/2022] Open
Abstract
Carbapenems are currently the preferred agents for the treatment of serious Acinetobacter infections. However, whether cefepime-cefpirome can be used to treat an Acinetobacter bloodstream infection (BSI) if it is active against the causative pathogen(s) is not clear. This study aimed to compare the efficacy of cefepime-cefpirome and carbapenem monotherapy in patients with Acinetobacter BSI. The population included 360 patients with monomicrobial Acinetobacter BSI receiving appropriate antimicrobial therapy admitted to four medical centers in Taiwan in 2012 to 2017. The predictors of 30-day mortality were determined by Cox regression analysis. The overall 30-day mortality rate in the appropriate antibiotic treatment group was 25.0% (90/360 patients). The crude 30-day mortality rates for cefepime-cefpirome and carbapenem therapy were 11.5% (7/61 patients) and 26.3% (21/80 patients), respectively. The patients receiving cefepime-cefpirome or carbapenem therapy were infected by Acinetobacter nosocomialis (51.8%), Acinetobacter baumannii (18.4%), and Acinetobacter pittii (12.1%). After adjusting for age, Sequential Organ Failure Assessment (SOFA) score, invasive procedures, and underlying diseases, cefepime-cefpirome therapy was not independently associated with a higher or lower 30-day mortality rate compared to that with the carbapenem therapy. SOFA score (hazard ratio [HR], 1.324; 95% confidence interval [CI], 1.137 to 1.543; P < 0.001) and neutropenia (HR, 7.060; 95% CI, 1.607 to 31.019; P = 0.010) were independent risk factors for 30-day mortality of patients receiving cefepime-cefpirome or carbapenem monotherapy. The incidence densities of 30-day mortality for cefepime-cefpirome versus carbapenem therapy were 0.40% versus 1.04%, respectively. The therapeutic response of cefepime-cefpirome therapy was comparable to that with carbapenems among patients with Acinetobacter BSI receiving appropriate antimicrobial therapy.
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Affiliation(s)
- Yea-Yuan Chang
- Division of Infectious Diseases, Department of Medicine, National Yang-Ming University Hospital, Yilan, Taiwan
- Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan
- Division of Infectious Diseases, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
- Faculty of Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan
- Division of Infectious Diseases, Department of Internal Medicine, Taipei City Hospital Renai Branch, Taipei, Taiwan
| | - Ya-Sung Yang
- Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Shang-Liang Wu
- School of Medicine, Griffith University, Gold Coast Campus, Southport, Queensland, Australia
| | - Yung-Chih Wang
- Division of Infectious Diseases and Tropical Medicine, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | | | - Yi-Tzu Lee
- Division of Infectious Diseases, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
- Faculty of Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan
- Department of Emergency Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
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37
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Kamoshida G, Akaji T, Takemoto N, Suzuki Y, Sato Y, Kai D, Hibino T, Yamaguchi D, Kikuchi-Ueda T, Nishida S, Unno Y, Tansho-Nagakawa S, Ubagai T, Miyoshi-Akiyama T, Oda M, Ono Y. Lipopolysaccharide-Deficient Acinetobacter baumannii Due to Colistin Resistance Is Killed by Neutrophil-Produced Lysozyme. Front Microbiol 2020; 11:573. [PMID: 32373082 PMCID: PMC7183746 DOI: 10.3389/fmicb.2020.00573] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 03/16/2020] [Indexed: 12/16/2022] Open
Abstract
Acinetobacter baumannii causes nosocomial infections due to its multidrug resistance and high environmental adaptability. Colistin is a polypeptide antibacterial agent that targets lipopolysaccharide (LPS) and is currently used to control serious multidrug-resistant Gram-negative bacterial infections, including those caused by A. baumannii. However, A. baumannii may acquire colistin resistance by losing their LPS. In mouse models, LPS-deficient A. baumannii have attenuated virulence. Nevertheless, the mechanism through which the pathogen is cleared by host immune cells is unknown. Here, we established colistin-resistant A. baumannii strains and analyzed possible mechanisms through which they are cleared by neutrophils. Colistin-resistant, LPS-deficient strains harbor mutations or insertion sequence (IS) in lpx genes, and introduction of intact lpx genes restored LPS deficiency. Analysis of interactions between these strains and neutrophils revealed that compared with wild type, LPS-deficient A. baumannii only weakly stimulated neutrophils, with consequent reduced levels of reactive oxygen species (ROS) and inflammatory cytokine production. Nonetheless, neutrophils preferentially killed LPS-deficient A. baumannii compared to wild-type strains. Moreover, LPS-deficient A. baumannii strains presented with increased sensitivities to antibacterial lysozyme and lactoferrin. We revealed that neutrophil-secreted lysozyme was the antimicrobial factor during clearance of LPS-deficient A. baumannii strains. These findings may inform the development of targeted therapeutics aimed to treat multidrug-resistant infections in immunocompromised patients who are unable to mount an appropriate cell-mediated immune response.
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Affiliation(s)
- Go Kamoshida
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan.,Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Takuya Akaji
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Norihiko Takemoto
- Pathogenic Microbe Laboratory, Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Yusuke Suzuki
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Yoshinori Sato
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Daichi Kai
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Taishi Hibino
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Daiki Yamaguchi
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Takane Kikuchi-Ueda
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Satoshi Nishida
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Yuka Unno
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Shigeru Tansho-Nagakawa
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Tsuneyuki Ubagai
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Tohru Miyoshi-Akiyama
- Pathogenic Microbe Laboratory, Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Masataka Oda
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Yasuo Ono
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
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38
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Loraine J, Heinz E, Soontarach R, Blackwell GA, Stabler RA, Voravuthikunchai SP, Srimanote P, Kiratisin P, Thomson NR, Taylor PW. Genomic and Phenotypic Analyses of Acinetobacter baumannii Isolates From Three Tertiary Care Hospitals in Thailand. Front Microbiol 2020; 11:548. [PMID: 32328045 PMCID: PMC7153491 DOI: 10.3389/fmicb.2020.00548] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 03/13/2020] [Indexed: 12/24/2022] Open
Abstract
Antibiotic resistant strains of Acinetobacter baumannii are responsible for a large and increasing burden of nosocomial infections in Thailand and other countries of Southeast Asia. New approaches to their control and treatment are urgently needed and an attractive strategy is to remove the bacterial polysaccharide capsule, and thus the protection from the host's immune system. To examine phylogenetic relationships, distribution of capsule chemotypes, acquired antibiotic resistance determinants, susceptibility to complement and other traits associated with systemic infection, we sequenced 191 isolates from three tertiary referral hospitals in Thailand and used phenotypic assays to characterize key aspects of infectivity. Several distinct lineages were circulating in three hospitals and the majority belonged to global clonal group 2 (GC2). Very high levels of resistance to carbapenems and other front-line antibiotics were found, as were a number of widespread plasmid replicons. A high diversity of capsule genotypes was encountered, with only three of these (KL6, KL10, and KL47) showing more than 10% frequency. Almost 90% of GC2 isolates belonged to the most common capsule genotypes and were fully resistant to the bactericidal action of human serum complement, most likely protected by their polysaccharide capsule, which represents a key determinant of virulence for systemic infection. Our study further highlights the importance to develop therapeutic strategies to remove the polysaccharide capsule from extensively drug-resistant A. baumanii during the course of systemic infection.
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Affiliation(s)
- Jessica Loraine
- School of Pharmacy, University College London, London, United Kingdom
| | - Eva Heinz
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom.,Wellcome Sanger Institute, Hinxton, Cambridge, United Kingdom
| | | | - Grace A Blackwell
- Wellcome Sanger Institute, Hinxton, Cambridge, United Kingdom.,European Bioinformatics Institute, European Molecular Biology Laboratory, Hinxton, Cambridge, United Kingdom
| | - Richard A Stabler
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | - Potjanee Srimanote
- Faculty of Allied Health Sciences, Thammasat University, Pathumtanee, Thailand
| | | | - Nicholas R Thomson
- Wellcome Sanger Institute, Hinxton, Cambridge, United Kingdom.,London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Peter W Taylor
- School of Pharmacy, University College London, London, United Kingdom
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Nosocomial Infection Agents of Şişli Hamidiye Etfal Training and Research Hospital: Comparison of 1995 and 2017 Data. MEDICAL BULLETIN OF SISLI ETFAL HOSPITAL 2020; 54:78-82. [PMID: 32377138 PMCID: PMC7192263 DOI: 10.14744/semb.2019.03271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 05/07/2019] [Indexed: 11/20/2022]
Abstract
Objectives: Healthcare-associated infections (HCAI), which are important causes of mortality and morbidity, are high cost but preventable infections. This study aimed to determine hospital infections and isolates in Şişli Hamidiye Etfal Training and Hospital and to determine our local data. The changes in the distribution of the isolates in this process were evaluated by comparing the data of 1995 and today. Methods: Materials sent to the microbiology laboratory of our hospital in 1995 and 2017 from the patients hospitalized in the period between June 1-December 31 were evaluated concerning hospital infection. The standard manual methods were used in 1995, while in 2017, MALDI-TOF MS was used for identification and BD Phoenix automated system for antibiotic susceptibility. Results: In 1995, in total, 100 bacteria were isolated from pediatric and adult patients, of which 48 Pseudomonas aeruginosa (48/100), 37 Klebsiella spp (37/100). In 2017, Acinetobacter baumannii causing an important resistance problem was found to be increased in number. The main hospital infection causes were Acinetobacter baumannii (37/179), Klebsiella spp (41/179). In 2017, bacterial diversity was also increased. Conclusion: Isolated strains, as in the past, are gram-negative bacteria, Pseudomonas spp decreased in 2017, and Acinetobacter spp increased. The findings suggest that the automated systems used in microbiology laboratories may have a role in the detection of bacterial diversity.
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40
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Pires S, Peignier A, Seto J, Smyth DS, Parker D. Biological sex influences susceptibility to Acinetobacter baumannii pneumonia in mice. JCI Insight 2020; 5:132223. [PMID: 32191638 DOI: 10.1172/jci.insight.132223] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 03/11/2020] [Indexed: 12/31/2022] Open
Abstract
Acinetobacter baumannii (A. baumannii) is an extremely versatile multidrug-resistant pathogen with a very high mortality rate; therefore, it has become crucial to understand the host response during its infection. Given the importance of mice for modeling infection and their role in preclinical drug development, equal emphasis should be placed on the use of both sexes. Through our studies using a murine model of acute pneumonia with A. baumannii, we observed that female mice were more susceptible to infection. Likewise, treatment of male mice with estradiol increased their susceptibility to infection. Analysis of the airway compartment revealed enhanced inflammation and reduced neutrophil and alveolar macrophage numbers compared with male mice. Depletion of either neutrophils or alveolar macrophages was important for bacterial clearance; however, depletion of alveolar macrophages further exacerbated female susceptibility because of severe alterations in metabolic homeostasis. Our data highlight the importance of using both sexes when assessing host immune pathways.
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Affiliation(s)
- Sílvia Pires
- Department of Pathology, Immunology and Laboratory Medicine, Center for Immunity and Inflammation, Rutgers New Jersey Medical School, Newark, New Jersey, USA
| | - Adeline Peignier
- Department of Pathology, Immunology and Laboratory Medicine, Center for Immunity and Inflammation, Rutgers New Jersey Medical School, Newark, New Jersey, USA
| | - Jeremy Seto
- Department of Biological Sciences, New York City College of Technology, Brooklyn, New York, New York, USA
| | - Davida S Smyth
- Department of Natural Sciences, Eugene Lang College of Liberal Arts at The New School, New York, New York, USA
| | - Dane Parker
- Department of Pathology, Immunology and Laboratory Medicine, Center for Immunity and Inflammation, Rutgers New Jersey Medical School, Newark, New Jersey, USA
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41
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Qamsari MM, Rasooli I, Chaudhuri S, Astaneh SDA, Schryvers AB. Hybrid Antigens Expressing Surface Loops of ZnuD From Acinetobacter baumannii Is Capable of Inducing Protection Against Infection. Front Immunol 2020; 11:158. [PMID: 32117294 PMCID: PMC7025491 DOI: 10.3389/fimmu.2020.00158] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 01/21/2020] [Indexed: 11/13/2022] Open
Abstract
Acinetobacter baumannii is an important human pathogen causing substantial mortality in hospitalized patients for which treatment with antibiotics has become problematic due to growing antibiotic resistance. In an attempt to develop alternative strategies for dealing with these serious infections surface antigens are being considered as targets for vaccines or immunotherapy. The surface receptor proteins required for zinc acquisition in Gram-negative bacterial pathogens have been proposed as vaccine targets due to their crucial role for growth in the human host. In this study we selected the putative ZnuD outer membrane receptor from A. baumannii as a target for vaccine development. Due to challenges in production of an integral outer membrane protein for vaccine production, we adopted a recently described hybrid antigen approach in which surface epitopes from the Neisseria meningitidis TbpA receptor protein were displayed on a derivative of the C-lobe of the surface lipoprotein TbpB, named the loopless C-lobe (LCL). A structural model for ZnuD was generated and four surface loops were selected for hybrid antigen production by computational approaches. Hybrid antigens were designed displaying the four selected loops (2, 5, 7, and 11) individually or together in a single hybrid antigen. The hybrid antigens along with ZnuD and the LCL scaffold were produced in the E. coli cytoplasm either as soluble antigens or as inclusion bodies, that were used to generate soluble antigens upon refolding. Mice were immunized with the hybrid antigens, ZnuD or LCL and then used in an A. baumannii sepsis model to evaluate their ability to protect against infection. As expected, the LCL scaffold did not induce a protective immune response, enabling us to attribute observed protection to the displayed loops. Immunization with the refolded ZnuD protein protected 63% of the mice while immunization with hybrid antigens displaying individual loops achieved between 25 and 50% protection. Notably, the mice immunized with the hybrid antigen displaying the four loops were completely protected from infection.
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Affiliation(s)
| | - Iraj Rasooli
- Department of Biology, Shahed University, Tehran, Iran.,Molecular Microbiology Research Center, Shahed University, Tehran, Iran
| | - Somshukla Chaudhuri
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB, Canada
| | | | - Anthony B Schryvers
- Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB, Canada
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42
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A Cyclic-di-GMP signalling network regulates biofilm formation and surface associated motility of Acinetobacter baumannii 17978. Sci Rep 2020; 10:1991. [PMID: 32029764 PMCID: PMC7005169 DOI: 10.1038/s41598-020-58522-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 01/16/2020] [Indexed: 11/30/2022] Open
Abstract
Acinetobacter baumannii has emerged as an increasing multidrug-resistant threat in hospitals and a common opportunistic nosocomial pathogen worldwide. However, molecular details of the pathogenesis and physiology of this bacterium largely remain to be elucidated. Here we identify and characterize the c-di-GMP signalling network and assess its role in biofilm formation and surface associated motility. Bioinformatic analysis revealed eleven candidate genes for c-di-GMP metabolizing proteins (GGDEF/EAL domain proteins) in the genome of A. baumannii strain 17978. Enzymatic activity of the encoded proteins was assessed by molecular cloning and expression in the model organisms Salmonella typhimurium and Vibrio cholerae. Ten of the eleven GGDEF/EAL proteins altered the rdar morphotype of S. typhimurium and the rugose morphotype of V. cholerae. The over expression of three GGDEF proteins exerted a pronounced effect on colony formation of A. baumannii on Congo Red agar plates. Distinct panels of GGDEF/EAL proteins were found to alter biofilm formation and surface associated motility of A. baumannii upon over expression. The GGDEF protein A1S_3296 appeared as a major diguanylate cyclase regulating macro-colony formation, biofilm formation and the surface associated motility. AIS_3296 promotes Csu pili mediated biofilm formation. We conclude that a functional c-di-GMP signalling network in A. baumannii regulates biofilm formation and surface associated motility of this increasingly important opportunistic bacterial pathogen.
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Vesicle-Mediated Dendritic Cell Activation in Acinetobacter baumannii Clinical Isolate, which Contributes to Th2 Response. J Immunol Res 2019; 2019:2835256. [PMID: 32083139 PMCID: PMC7012244 DOI: 10.1155/2019/2835256] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 12/12/2019] [Indexed: 12/13/2022] Open
Abstract
Acinetobacter baumannii, as a nonfermentation Gram-negative bacterium, mainly cause nosocomial infections in critically ill patients. With the widespread of multidrug-resistant Acinetobacter baumannii, the urgency of developing effective therapy options has been emphasized nowadays. Outer membrane vesicles derived from bacteria show potential vaccine effects against bacterial infection in recent study. Our present research is aimed at investigating the mechanisms involved in immune protection of mice after outer membrane vesicle immunization. As our data showed, the outer membrane vesicle from an Acinetobacter baumannii clinical strain could activate bone marrow-derived dendritic cells (BMDCs) to promote Th2 activity together with humoral immune responses to Acinetobacter baumannii-induced sepsis, which might enlighten people to have a better understanding of OMVs' role as a vaccine to prevent bacterial infections.
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Potential Mechanisms of Mucin-Enhanced Acinetobacter baumannii Virulence in the Mouse Model of Intraperitoneal Infection. Infect Immun 2019; 87:IAI.00591-19. [PMID: 31405959 DOI: 10.1128/iai.00591-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 08/07/2019] [Indexed: 12/21/2022] Open
Abstract
Porcine mucin has been commonly used to enhance the infectivity of bacterial pathogens, including Acinetobacter baumannii, in animal models, but the mechanisms for enhancement by mucin remain relatively unknown. In this study, using the mouse model of intraperitoneal (i.p.) mucin-enhanced A. baumannii infection, we characterized the kinetics of bacterial replication and dissemination and the host innate immune responses, as well as their potential contribution to mucin-enhanced bacterial virulence. We found that mucin, either admixed with or separately injected with the challenge bacterial inoculum, was able to enhance the tissue and blood burdens of A. baumannii strains of different virulence. Intraperitoneal injection of A. baumannii-mucin or mucin alone induced a significant but comparable reduction of peritoneal macrophages and lymphocytes, accompanied by a significant neutrophil recruitment and early interleukin-10 (IL-10) responses, suggesting that the resulting inflammatory cellular and cytokine responses were largely induced by the mucin. Depletion of peritoneal macrophages or neutralization of endogenous IL-10 activities showed no effect on the mucin-enhanced infectivity. However, pretreatment of mucin with iron chelator DIBI, but not deferoxamine, partially abolished its virulence enhancement ability, and replacement of mucin with iron significantly enhanced the bacterial burdens in the peritoneal cavity and lung. Taken together, our results favor the hypothesis that iron at least partially contributes to the mucin-enhanced infectivity of A. baumannii in this model.
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Alcántar-Curiel MD, Rosales-Reyes R, Jarillo-Quijada MD, Gayosso-Vázquez C, Fernández-Vázquez JL, Toledano-Tableros JE, Giono-Cerezo S, Garza-Villafuerte P, López-Huerta A, Vences-Vences D, Morfín-Otero R, Rodríguez-Noriega E, López-Álvarez MDR, Espinosa-Sotero MDC, Santos-Preciado JI. Carbapenem-Resistant Acinetobacter baumannii in Three Tertiary Care Hospitals in Mexico: Virulence Profiles, Innate Immune Response and Clonal Dissemination. Front Microbiol 2019; 10:2116. [PMID: 31616391 PMCID: PMC6764332 DOI: 10.3389/fmicb.2019.02116] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 08/28/2019] [Indexed: 01/08/2023] Open
Abstract
Acinetobacter baumannii is one of the most important nosocomial pathogens distributed worldwide. Due to its multidrug-resistance and the propensity for the epidemic spread, the World Health Organization includes this bacterium as a priority health issue for development of new antibiotics. The aims of this study were to investigate the antimicrobial resistance profile, the clonal relatedness, the virulence profiles, the innate host immune response and the clonal dissemination of A. baumannii in Hospital Civil de Guadalajara (HCG), Hospital Regional General Ignacio Zaragoza (HRGIZ) and Pediatric ward of the Hospital General de México Eduardo Liceaga (HGM-P). A total of 252 A. baumannii clinical isolates were collected from patients with nosocomial infections in these hospitals between 2015 and 2016. These isolates showed a multidrug-resistant profile and most of them only susceptible to colistin. Furthermore, 83.3 and 36.9% of the isolates carried the blaOXA–24 and blaTEM–1 genes for resistance to carbapenems and β-lactam antibiotics, respectively. The clonal relatedness assessed by pulsed-field gel electrophoresis (PFGE) and by multi-locus sequence typing (MLST) demonstrated a genetic diversity. Remarkably, the ST136, ST208 and ST369 that belonged to the clonal complex CC92 and ST758 and ST1054 to the CC636 clonal complex were identified. The ST136 was a high-risk persistent clone involved in an outbreak at HCG and ST369 were related to the first carbapenem-resistant A. baumannii outbreak in HRGIZ. Up to 58% isolates were able to attach to A549 epithelial cells and 14.5% of them induced >50% of cytotoxicity. A549 cells infected with A. baumannii produced TNFα, IL-6 and IL-1β and the oxygen and nitrogen reactive species that contributes to the development of an inflammatory immune response. Up to 91.3% of clinical isolates were resistant to normal human serum activity. Finally, 98.5% of the clinical isolates were able to form biofilm over polystyrene tubes. In summary, these results demonstrate the increasingly dissemination of multidrug-resistant A. baumannii clones in three hospitals in Mexico carrying diverse bacterial virulence factors that could contribute to establishment of the innate immune response associated to the fatality risks in seriously ill patients.
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Affiliation(s)
- María Dolores Alcántar-Curiel
- Laboratorio de Infectología, Microbiología e Inmunología Clínicas, Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Roberto Rosales-Reyes
- Laboratorio de Infectología, Microbiología e Inmunología Clínicas, Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Ma Dolores Jarillo-Quijada
- Laboratorio de Infectología, Microbiología e Inmunología Clínicas, Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Catalina Gayosso-Vázquez
- Laboratorio de Infectología, Microbiología e Inmunología Clínicas, Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - José Luis Fernández-Vázquez
- Laboratorio de Infectología, Microbiología e Inmunología Clínicas, Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - José Eduardo Toledano-Tableros
- Laboratorio de Infectología, Microbiología e Inmunología Clínicas, Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico.,Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Silvia Giono-Cerezo
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Paola Garza-Villafuerte
- Laboratorio de Infectología, Microbiología e Inmunología Clínicas, Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Arath López-Huerta
- Laboratorio de Infectología, Microbiología e Inmunología Clínicas, Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Daniela Vences-Vences
- Laboratorio de Infectología, Microbiología e Inmunología Clínicas, Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Rayo Morfín-Otero
- Hospital Civil de Guadalajara Fray Antonio Alcalde, Instituto de Patología Infecciosa y Experimental, UDG, Guadalajara, Mexico
| | - Eduardo Rodríguez-Noriega
- Hospital Civil de Guadalajara Fray Antonio Alcalde, Instituto de Patología Infecciosa y Experimental, UDG, Guadalajara, Mexico
| | | | | | - José Ignacio Santos-Preciado
- Laboratorio de Infectología, Microbiología e Inmunología Clínicas, Unidad de Investigación en Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
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46
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Tohidinia M, Moshtaghioun SM, Sefid F, Falahati A. Functional Exposed Amino Acids of CarO Analysis as a Potential Vaccine Candidate in Acinetobacter Baumannii. Int J Pept Res Ther 2019. [DOI: 10.1007/s10989-019-09923-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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47
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Toll-Like Receptors 2 and 4 Modulate Pulmonary Inflammation and Host Factors Mediated by Outer Membrane Vesicles Derived from Acinetobacter baumannii. Infect Immun 2019; 87:IAI.00243-19. [PMID: 31262980 DOI: 10.1128/iai.00243-19] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 06/11/2019] [Indexed: 11/20/2022] Open
Abstract
Pneumonia due to Gram-negative bacteria is associated with high mortality. Acinetobacter baumannii is a Gram-negative bacterium that is associated with hospital-acquired and ventilator-associated pneumonia. Bacteria have been described to release outer membrane vesicles (OMVs) that are capable of mediating systemic inflammation. The mechanism by which A. baumannii OMVs mediate inflammation is not fully defined. We sought to investigate the roles that Toll-like receptors (TLRs) play in A. baumannii OMV-mediated pulmonary inflammation. We isolated OMVs from A. baumannii cultures and intranasally introduced the OMVs into mice. Intranasal introduction of A. baumannii OMVs mediated pulmonary inflammation, which is associated with neutrophil recruitment and weight loss. In addition, A. baumannii OMVs increased the release of several chemokines and cytokines in the mouse lungs. The proinflammatory responses were partially inhibited in TLR2- and TLR4-deficient mice compared to those of wild-type mice. This study highlights the important roles of TLRs in A. baumannii OMV-induced pulmonary inflammation in vivo.
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48
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Liao C, Li Y, Tjong SC. Antibacterial Activities of Aliphatic Polyester Nanocomposites with Silver Nanoparticles and/or Graphene Oxide Sheets. NANOMATERIALS (BASEL, SWITZERLAND) 2019; 9:E1102. [PMID: 31374855 PMCID: PMC6724040 DOI: 10.3390/nano9081102] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 07/21/2019] [Accepted: 07/25/2019] [Indexed: 12/18/2022]
Abstract
Aliphatic polyesters such as poly(lactic acid) (PLA), polycaprolactone (PCL) and poly(lactic-co-glycolic) acid (PLGA) copolymers have been widely used as biomaterials for tissue engineering applications including: bone fixation devices, bone scaffolds, and wound dressings in orthopedics. However, biodegradable aliphatic polyesters are prone to bacterial infections due to the lack of antibacterial moieties in their macromolecular chains. In this respect, silver nanoparticles (AgNPs), graphene oxide (GO) sheets and AgNPs-GO hybrids can be used as reinforcing nanofillers for aliphatic polyesters in forming antimicrobial nanocomposites. However, polymeric matrix materials immobilize nanofillers to a large extent so that they cannot penetrate bacterial membrane into cytoplasm as in the case of colloidal nanoparticles or nanosheets. Accordingly, loaded GO sheets of aliphatic polyester nanocomposites have lost their antibacterial functions such as nanoknife cutting, blanket wrapping and membrane phospholipid extraction. In contrast, AgNPs fillers of polyester nanocomposites can release silver ions for destroying bacterial cells. Thus, AgNPs fillers are more effective than loaded GO sheets of polyester nanocomposiites in inhibiting bacterial infections. Aliphatic polyester nanocomposites with AgNPs and AgNPs-GO fillers are effective to kill multi-drug resistant bacteria that cause medical device-related infections.
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Affiliation(s)
- Chengzhu Liao
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China.
| | - Yuchao Li
- Department of Materials Science and Engineering, Liaocheng University, Liaocheng 252000, China
| | - Sie Chin Tjong
- Department of Physics, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong 999077, China.
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49
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Rodman N, Martinez J, Fung S, Nakanouchi J, Myers AL, Harris CM, Dang E, Fernandez JS, Liu C, Mendoza AM, Jimenez V, Nikolaidis N, Brennan CA, Bonomo RA, Sieira R, Ramirez MS. Human Pleural Fluid Elicits Pyruvate and Phenylalanine Metabolism in Acinetobacter baumannii to Enhance Cytotoxicity and Immune Evasion. Front Microbiol 2019; 10:1581. [PMID: 31379769 PMCID: PMC6650585 DOI: 10.3389/fmicb.2019.01581] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 06/25/2019] [Indexed: 01/13/2023] Open
Abstract
Acinetobacter baumannii (Ab) is one of the most treacherous pathogens among those causing hospital-acquired pneumonia (HAP). A. baumannii possesses an adaptable physiology, seen not only in its antibiotic resistance and virulence phenotypes but also in its metabolic versatility. In this study, we observed that A. baumannii undergoes global transcriptional changes in response to human pleural fluid (PF), a key host-derived environmental signal. Differential gene expression analyses combined with experimental approaches revealed changes in A. baumannii metabolism, affecting cytotoxicity, persistence, bacterial killing, and chemotaxis. Over 1,220 genes representing 55% of the differentially expressed transcriptomic data corresponded to metabolic processes, including the upregulation of glutamate, short chain fatty acid, and styrene metabolism. We observed an upregulation by 1.83- and 2.61-fold of the pyruvate dehydrogenase complex subunits E3 and E2, respectively. We also found that pyruvate (PYR), in conjunction with PF, triggers an A. baumannii pathogenic behavior that adversely impacts human epithelial cell viability. Interestingly, PF also amplified A. baumannii cytotoxicity against murine macrophages, suggesting an immune evasion strategy implemented by A. baumannii. Moreover, we uncovered opposing metabolic strategies dependent on the degree of pathogenicity of the strains, where less pathogenic strains demonstrated greater utilization of PYR to promote persister formation in the presence of PF. Additionally, our transcriptomic analysis and growth studies of A. baumannii suggest the existence of an alternative phenylalanine (PA) catabolic route independent of the phenylacetic acid pathway, which converts PA to phenylpyruvate (PP) and shuttles intermediates into styrene metabolism. This alternative route promoted a neutrophil-evasive state, as PF-induced degradation of PP significantly reduced overall human neutrophil chemotaxis in ex vivo chemotactic assays. Taken together, these data highlight A. baumannii pathoadaptabililty in response to host signals and provide further insight into the role of bacterial metabolism in virulence traits, antibiotic persistence strategies, and host innate immune evasion.
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Affiliation(s)
- Nyah Rodman
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States
| | - Jasmine Martinez
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States
| | - Sammie Fung
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States
| | - Jun Nakanouchi
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States
| | - Amber L Myers
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States
| | - Caitlin M Harris
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States
| | - Emily Dang
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States
| | - Jennifer S Fernandez
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States
| | - Christine Liu
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States
| | - Anthony M Mendoza
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States
| | - Veronica Jimenez
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States
| | - Nikolas Nikolaidis
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States
| | - Catherine A Brennan
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States
| | - Robert A Bonomo
- Medical Service and Geriatrics Research, Education and Clinical Center (GRECC), Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH, United States.,Departments of Medicine, Pharmacology, Molecular Biology and Microbiology, Biochemistry, Proteomics and Bioinformatics, Case Western Reserve University School of Medicine, Cleveland, OH, United States.,CWRU-Cleveland VAMC Center for Antimicrobial Resistance and Epidemiology (Case VA CARES), Cleveland, OH, United States
| | - Rodrigo Sieira
- Fundacioìn Instituto Leloir-IIBBA CONICET, Buenos Aires, Argentina
| | - Maria Soledad Ramirez
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States
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50
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Morris FC, Dexter C, Kostoulias X, Uddin MI, Peleg AY. The Mechanisms of Disease Caused by Acinetobacter baumannii. Front Microbiol 2019; 10:1601. [PMID: 31379771 PMCID: PMC6650576 DOI: 10.3389/fmicb.2019.01601] [Citation(s) in RCA: 155] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 06/26/2019] [Indexed: 01/29/2023] Open
Abstract
Acinetobacter baumannii is a Gram negative opportunistic pathogen that has demonstrated a significant insurgence in the prevalence of infections over recent decades. With only a limited number of “traditional” virulence factors, the mechanisms underlying the success of this pathogen remain of great interest. Major advances have been made in the tools, reagents, and models to study A. baumannii pathogenesis, and this has resulted in a substantial increase in knowledge. This article provides a comprehensive review of the bacterial virulence factors, the host immune responses, and animal models applicable for the study of this important human pathogen. Collating the most recent evidence characterizing bacterial virulence factors, their cellular targets and genetic regulation, we have encompassed numerous aspects important to the success of this pathogen, including membrane proteins and cell surface adaptations promoting immune evasion, mechanisms for nutrient acquisition and community interactions. The role of innate and adaptive immune responses is reviewed and areas of paucity in our understanding are highlighted. Finally, with the vast expansion of available animal models over recent years, we have evaluated those suitable for use in the study of Acinetobacter disease, discussing their advantages and limitations.
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Affiliation(s)
- Faye C Morris
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Carina Dexter
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Xenia Kostoulias
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Muhammad Ikhtear Uddin
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Anton Y Peleg
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia.,Department of Infectious Diseases, The Alfred Hospital and Central Clinical School, Monash University, Melbourne, VIC, Australia
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