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Aldali JA. Acinetobacter baumannii: A multidrug-resistant pathogen, has emerged in Saudi Arabia. Saudi Med J 2023; 44:732-744. [PMID: 37582561 PMCID: PMC10425629 DOI: 10.15537/smj.2023.44.8.20230194] [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] [Indexed: 08/17/2023] Open
Abstract
A significant opportunistic pathogen, Acinetobacter baumannii (A. baumannii) has evolved mechanisms of resistance to a wide variety of antimicrobials, including carbapenems. In this article, we assessed the prevalence, risk factors, antimicrobial sensitivity, and resistance mechanisms among A. baumannii in several locations in Saudi Arabia. Hospital-acquired infections caused by A. baumannii were prevalent in the country due to a variety of reasons, such as the high number of critically ill patients, the frequency of gastrointestinal colonization, and the widespread use of antimicrobial medications. There has been an increase in the frequency of A. baumannii strains that are resistant to several antimicrobials, including carbapenems. Hospitals are a breeding ground for multidrug-resistant A. baumannii due to the widespread use of broad-spectrum antibiotics, the potential for patient-to-patient transmission of the bacteria, the high risk of infection during invasive intensive care unit procedures, and the high frequency with which diabetic and cancer patients in hospitals undergo invasive diagnostic and therapeutic procedures. Combinations of colistin and tigecycline with carbapenems or other antibiotics remain the best treatment option and are relatively safe to treat patients with multidrug resistance (MDR) A. baumannii infections, despite the rising incidence of resistance to these drugs observed in many hospitals. The prevalence of multidrug-resistant A. baumannii in Saudi hospitals calls for in-depth research into the underlying molecular mechanisms of multidrug resistance. In addition, a better understanding of A. baumannii resistance patterns and the establishment of a treatment protocol to reduce the infection burden in Saudi Arabia could benefit from the implementation of a local antibiogram database in tandem with a national antimicrobial stewardship and infection prevention program.
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Affiliation(s)
- Jehad A. Aldali
- From the Department of Pathology, College of Medicine, Imam Mohammad Ibn Saud Islamic University, Riyadh, Kingdom of Saudi Arabia.
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2
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Khodabakhshi D, Vaseghi G, Mirzaee A, Eskandarinia A, Kharazi AZ. Antimicrobial activity and wound healing effect of a novel natural ointment: an in vitro and in vivo study. J Wound Care 2023; 32:S18-S26. [PMID: 37300867 DOI: 10.12968/jowc.2023.32.sup6.s18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Infection and pathological disorders, such as cellular disorders, ischaemia, neuropathy and angiogenesis, are considered the most critical factors which cause a delay in the wound healing process in patients with diabetes. This study aimed to investigate the effect of an ointment based on ostrich oil containing honey, beeswax, and ethanolic extracts of Nigella sativa, propolis and Cassia angustifolia on the wound healing process of diabetic rats. Gas chromatography/mass spectrometry analysis showed caffeic acid and pinostrobin chalcone molecules present in propolis, giving antibacterial and antifungal properties to the compound. The antibacterial assessment showed the ointment had remarkable antibacterial activity against Staphylococcus aureus (8.6±0.28mm), Escherichia coli (9.4±0.31mm), Acinetobacter baumannii (7.2±0.23mm) and Pseudomonas aeruginosa (13.9±0.42mm). In vivo results showed the ointment significantly accelerated wound healing and increased collagen deposition compared with the control (p<0.05). Histopathology evaluation also showed hair follicles, sebaceous glands and vessels in the group that used the ointment. These results proved successful and diabetic wound healing was rapid. Therefore, it could be concluded that the fabricated ointment could be a suitable candidate for wound healing.
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Affiliation(s)
- Darioush Khodabakhshi
- Department of Biomaterials, Tissue Engineering, and Nanotechnology, School of Advanced Technologies in Medicine, Isfahan University of Medical Sciences, Hezarjreeb St., 8174673461 Isfahan, Iran
| | - Golnaz Vaseghi
- Isfahan Cardiovascular Research Center, Cardiovascular Research Institute, Isfahan University of Medical Sciences, Hezarjreeb St., 8174673461, Isfahan, Iran
| | - Arezoo Mirzaee
- Department of Bacteriology and Virology, School of Medicine, Isfahan University of Medical Sciences, Hezarjreeb St., 8174673461, Isfahan, Iran
| | - Asghar Eskandarinia
- Department of Biomaterials, Tissue Engineering, and Nanotechnology, School of Advanced Technologies in Medicine, Isfahan University of Medical Sciences, Hezarjreeb St., 8174673461 Isfahan, Iran
| | - Anousheh Zargar Kharazi
- Department of Biomaterials, Tissue Engineering, and Nanotechnology, School of Advanced Technologies in Medicine, Isfahan University of Medical Sciences, Hezarjreeb St., 8174673461 Isfahan, Iran
- Applied Physiology Research Center, Isfahan University of Medical Sciences, Hezarjreeb St., 8174673461, Isfahan, Iran
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3
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El-Kafrawy SA, Abbas AT, Oelkrug C, Tahoon M, Ezzat S, Zumla A, Azhar EI. IgY antibodies: The promising potential to overcome antibiotic resistance. Front Immunol 2023; 14:1065353. [PMID: 36742328 PMCID: PMC9896010 DOI: 10.3389/fimmu.2023.1065353] [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: 10/09/2022] [Accepted: 01/05/2023] [Indexed: 01/22/2023] Open
Abstract
Antibiotic resistant bacteria are a growing threat to global health security. Whilst the emergence of antimicrobial resistance (AMR) is a natural phenomenon, it is also driven by antibiotic exposure in health care, agriculture, and the environment. Antibiotic pressure and inappropriate use of antibiotics are important factors which drive resistance. Apart from their use to treat bacterial infections in humans, antibiotics also play an important role in animal husbandry. With limited antibiotic options, alternate strategies are required to overcome AMR. Passive immunization through oral, nasal and topical administration of egg yolk-derived IgY antibodies from immunized chickens were recently shown to be effective for treating bacterial infections in animals and humans. Immunization of chickens with specific antigens offers the possibility of creating specific antibodies targeting a wide range of antibiotic-resistant bacteria. In this review, we describe the growing global problem of antimicrobial resistance and highlight the promising potential of the use of egg yolk IgY antibodies for the treatment of bacterial infections, particularly those listed in the World Health Organization priority list.
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Affiliation(s)
- Sherif A El-Kafrawy
- Special Infectious Agents Unit-BSL3, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Clinical Pathology, National Liver Institute, Menoufia University, Shebin El-Kom, Egypt
| | - Aymn T Abbas
- Special Infectious Agents Unit-BSL3, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia.,Biotechnology Research Laboratories, Gastroenterology, Surgery Centre, Mansoura University, Mansoura, Egypt
| | | | - Marwa Tahoon
- Epidemiology and Preventive Medicine Department, National Liver Institute, Menoufia University, Shebin El-Kom, Egypt
| | - Sameera Ezzat
- Epidemiology and Preventive Medicine Department, National Liver Institute, Menoufia University, Shebin El-Kom, Egypt.,MARC for Medical Services and Scientific Research, 6th of October City, Giza, Egypt
| | - Alimuddin Zumla
- Special Infectious Agents Unit-BSL3, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Infection, Division of Infection and Immunity, Centre for Clinical Microbiology, University College London, London, United Kingdom.,National Institute for Health and Care Research (NIHR) Biomedical Research Centre, University College London Hospitals, London, United Kingdom
| | - Esam I Azhar
- Special Infectious Agents Unit-BSL3, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
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Xia D, Wang S, Yao R, Han Y, Zheng L, He P, Liu Y, Yang L. Pyroptosis in sepsis: Comprehensive analysis of research hotspots and core genes in 2022. Front Mol Biosci 2022; 9:955991. [PMID: 36032662 PMCID: PMC9402944 DOI: 10.3389/fmolb.2022.955991] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Accepted: 07/15/2022] [Indexed: 12/02/2022] Open
Abstract
Sepsis, a life-threatening disease caused by dysregulated host response to infection, is a major public health problem with a high mortality and morbidity rate. Pyroptosis is a new type of programmed cell death discovered in recent years, which has been proved to play an important role in sepsis. Nevertheless, there is no comprehensive report, which can help researchers get a quick overview and find research hotspots. Thus, we aimed to identify the study status and knowledge structures of pyroptosis in sepsis and summarize the key mechanism of pyroptosis in sepsis. The data were retrieved and downloaded from the WOS database. Software such as VOSviewer was used to analyze these publications. Key genes were picked out by using (https://www.genecards.org) and (http://www.bioinformatics.com). Then, Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were used to performed these key genes. From 2011 to 2021, a total of 299 papers met the search criteria, and the global interest in pyroptosis in sepsis measured by the value of (RRI) has started to increase since 2016. China ranked first in the number of publications, followed by the USA. The journal Frontiers in Immunology published the most relevant articles. Through keyword co-occurrence analysis, the high-frequency subject terms were divided into three clusters like “animal research”, “cell research,” and “molecular research” clusters. “mir,” “aki,” “monocyte,” and “neutrophil” were the newest keywords that may be the hotspot. In addition, a total of 15 genes were identified as hub genes. TNF, IL-1β, AKT1, CASP1, and STAT3 were highly expressed in lung tissues, thymus tissues, and lymphocytes. KEGG analysis indicated that pyroptosis may play a vital role in sepsis via the NOD, PI3K/AKT, and MAPK/JNK pathways. Through the quantitative analysis of the literature on pyroptosis in sepsis, we revealed the current status and hotspots of research in this field and provided some guidance for further studies.
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Affiliation(s)
- Demeng Xia
- Luodian Clinical Drug Research Center, Shanghai Baoshan Luodian Hospital, Shanghai University, Shanghai, China
| | - Sheng Wang
- Department of Emergency, Changhai Hospital, Naval Medical University, Shanghai, China
| | - Renqi Yao
- Translational Medicine Research Center, Fourth Medical Center and Medical Innovation Research Division of the Chinese PLA General Hospital, Beijing, China
| | - Yuexue Han
- Department of Clinical Medicine, Qing Dao University, Qing Dao, Shan Dong, China
| | - Liyu Zheng
- Translational Medicine Research Center, Fourth Medical Center and Medical Innovation Research Division of the Chinese PLA General Hospital, Beijing, China
| | - Pengyi He
- Translational Medicine Research Center, Fourth Medical Center and Medical Innovation Research Division of the Chinese PLA General Hospital, Beijing, China
| | - Ying Liu
- Institute of Translational Medicine, Shanghai University, Shanghai, China
- *Correspondence: Ying Liu, ; Lu Yang,
| | - Lu Yang
- Clinical Research Center, Shanghai Baoshan Luodian Hospital, Shanghai University, Shanghai, China
- *Correspondence: Ying Liu, ; Lu Yang,
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Abstract
Background: Extremely drug-resistant (XDR) Acinetobacter baumannii is a notorious and frequently encountered pathogen demanding novel therapeutic interventions. An initial monoclonal antibody (MAb), C8, raised against A. baumannii capsule proved a highly effective treatment against a minority of clinical isolates. To overcome this limitation, we broadened coverage by developing a second antibody for use in a combination regimen. Methods: We sought to develop an additional anti-A. baumannii MAb through hybridoma technology by immunizing mice with sublethal inocula of virulent, XDR clinical isolates not bound by MAb C8. Results: We identified a new antibacterial MAb, 65, which bound to strains in a pattern distinct from and complementary to MAb C8. MAb 65 enhanced macrophage opsonophagocytosis of targeted strains and markedly improved survival in lethal bacteremic sepsis and aspiration pneumonia murine models of A. baumannii infection. MAb 65 was also synergistic with colistin, substantially enhancing protection compared to monotherapy. Treatment with MAb 65 significantly reduced blood bacterial density, ameliorated cytokine production (IL-1β, IL-6, IL-10, and TNF), and sepsis biomarkers. Conclusions: We describe a novel MAb targeting A. baumannii that broadens immunotherapeutic strain coverage, is highly potent and effective, and synergistically improves outcomes in combination with antibiotics.
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Miró-Canturri A, Ayerbe-Algaba R, Villodres ÁR, Pachón J, Smani Y. Repositioning rafoxanide to treat Gram-negative bacilli infections. J Antimicrob Chemother 2021; 75:1895-1905. [PMID: 32240294 DOI: 10.1093/jac/dkaa103] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 02/07/2020] [Accepted: 02/25/2020] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVES Repurposing drugs provides a new approach to the fight against MDR Gram-negative bacilli (MDR-GNB). Rafoxanide, a veterinary antihelminthic drug, has shown antibacterial activity in vitro against Gram-positive bacteria. We aimed to analyse the in vitro and in vivo efficacy of rafoxanide in combination with colistin against colistin-susceptible (Col-S) and colistin-resistant (Col-R) GNB. METHODS A collection of Col-S and Col-R Acinetobacter baumannii, Pseudomonas aeruginosa and Klebsiella pneumoniae were used. Chequerboard and time-kill curve analyses were performed to determine the synergy between rafoxanide and colistin. Changes in membrane structure and permeability were analysed using transmission electron microscopy and fluorescence assays. A murine peritoneal sepsis model using Col-R strains of these pathogens was performed to study the efficacy of rafoxanide (10 mg/kg/24 h, IV), colistimethate sodium (CMS) (20 mg/kg/8 h, intraperitoneally) and rafoxanide (10 mg/kg/24 h, IV) plus CMS (20 mg/kg/8 h, intraperitoneally) for 72 h. RESULTS Rafoxanide showed MICs ≥256 mg/L for all Col-S and Col-R strains. Chequerboard and time-kill curve analyses showed that rafoxanide (1 mg/L) is more synergistic with colistin against Col-R than Col-S strains. Col-R, but not Col-S, strains treated with rafoxanide demonstrated higher membrane permeabilization. Transmission electron microscopy visualization confirmed that Col-R strains suffer morphological changes. In the murine peritoneal sepsis model with Col-R strains, rafoxanide plus CMS, compared with CMS alone, increased mouse survival to 53.8% and 73.3%, and reduced bacterial loads in tissues and blood between 2.34 and 4.99 log10 cfu/g or mL, respectively. CONCLUSIONS Rafoxanide repurposing, as monotherapy and in combination with CMS, may address the urgent need for new treatments for infections caused by MDR-GNB.
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Affiliation(s)
- Andrea Miró-Canturri
- Clinical Unit of Infectious Diseases, Microbiology and Preventive Medicine, University Hospital Virgen del Rocío, Seville, Spain.,Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC/University of Seville, Seville, Spain
| | - Rafael Ayerbe-Algaba
- Clinical Unit of Infectious Diseases, Microbiology and Preventive Medicine, University Hospital Virgen del Rocío, Seville, Spain.,Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC/University of Seville, Seville, Spain
| | - Ángel Rodríguez Villodres
- Clinical Unit of Infectious Diseases, Microbiology and Preventive Medicine, University Hospital Virgen del Rocío, Seville, Spain.,Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC/University of Seville, Seville, Spain
| | - Jerónimo Pachón
- Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC/University of Seville, Seville, Spain.,Department of Medicine, University of Seville, Seville, Spain
| | - Younes Smani
- Clinical Unit of Infectious Diseases, Microbiology and Preventive Medicine, University Hospital Virgen del Rocío, Seville, Spain.,Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC/University of Seville, Seville, Spain
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7
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Mat Rahim N, Lee H, Strych U, AbuBakar S. Facing the challenges of multidrug-resistant Acinetobacter baumannii: progress and prospects in the vaccine development. Hum Vaccin Immunother 2021; 17:3784-3794. [PMID: 34106809 PMCID: PMC8437540 DOI: 10.1080/21645515.2021.1927412] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
In 2017, the World Health Organization (WHO) named A. baumannii as one of the three antibiotic-resistant bacterial species on its list of global priority pathogens in dire need of novel and effective treatment. With only polymyxin and tigecycline antibiotics left as last-resort treatments, the need for novel alternative approaches to the control of this bacterium becomes imperative. Vaccines against numerous bacteria have had impressive records in reducing the burden of the respective diseases and addressing antimicrobial resistance; as in the case of Haemophilus influenzae type b . A similar approach could be appropriate for A. baumannii. Toward this end, several potentially protective antigens against A. baumannii were identified and evaluated as vaccine antigen candidates. A licensed vaccine for the bacteria, however, is still not in sight. Here we explore and discuss challenges in vaccine development against A. baumannii and the promising approaches for improving the vaccine development process.
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Affiliation(s)
- NorAziyah Mat Rahim
- Tropical Infectious Diseases Research and Education Center (TIDREC), Universiti Malaya, Kuala Lumpur, Malaysia.,Texas Children's Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, TX, USA.,Virology Unit, Institute for Medical Research, National Institute of Health Complex, Setia Alam, Malaysia
| | - HaiYen Lee
- Tropical Infectious Diseases Research and Education Center (TIDREC), Universiti Malaya, Kuala Lumpur, Malaysia
| | - Ulrich Strych
- Texas Children's Hospital Center for Vaccine Development, Baylor College of Medicine, Houston, TX, USA
| | - Sazaly AbuBakar
- Tropical Infectious Diseases Research and Education Center (TIDREC), Universiti Malaya, Kuala Lumpur, Malaysia
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8
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Nielsen TB, Yan J, Luna BM, Talyansky Y, Slarve M, Bonomo RA, Spellberg B. Monoclonal antibody requires immunomodulation for efficacy against Acinetobacter baumannii infection. J Infect Dis 2021; 224:2133-2147. [PMID: 34036366 DOI: 10.1093/infdis/jiab265] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 05/12/2021] [Indexed: 02/06/2023] Open
Abstract
Monoclonal antibodies (MAbs) are gaining significant momentum as novel therapeutics for infections caused by antibiotic-resistant bacteria. We evaluated the mechanism by which anti-bacterial MAb therapy protects against Acinetobacter baumannii infections. Anti-capsular MAb enhanced macrophage opsonophagocytosis and rescued mice from lethal infections by harnessing complement, macrophages, and neutrophils, yet the degree of bacterial burden did not correlate with survival. Furthermore, MAb therapy reduced pro-inflammatory (IL-1β, IL-6, TNFα) and anti-inflammatory (IL-10) cytokines, which correlated inversely with survival. Although disrupting IL-10 abrogated the survival advantage conferred by the MAb, IL-10-knockout mice treated with MAb could still survive if TNFα production was suppressed directly (via anti-TNFα neutralizing antibody) or indirectly (via macrophage depletion). Thus, even for a MAb that enhances microbial clearance via opsonophagocytosis, clinical efficacy required modulation of pro- and anti-inflammatory cytokines. These findings may inform future MAb development targeting bacteria that trigger the sepsis cascade.
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Affiliation(s)
- Travis B Nielsen
- Stritch School of Medicine at Loyola University Chicago, Maywood, IL, 60153, United States.,Department of Medicine and Department of Molecular Microbiology & Immunology, Keck School of Medicine at the University of Southern California (USC), Los Angeles, CA, 90033, United States
| | - Jun Yan
- Department of Medicine and Department of Molecular Microbiology & Immunology, Keck School of Medicine at the University of Southern California (USC), Los Angeles, CA, 90033, United States
| | - Brian M Luna
- Department of Medicine and Department of Molecular Microbiology & Immunology, Keck School of Medicine at the University of Southern California (USC), Los Angeles, CA, 90033, United States
| | - Yuli Talyansky
- Department of Medicine and Department of Molecular Microbiology & Immunology, Keck School of Medicine at the University of Southern California (USC), Los Angeles, CA, 90033, United States
| | - Matthew Slarve
- Department of Medicine and Department of Molecular Microbiology & Immunology, Keck School of Medicine at the University of Southern California (USC), Los Angeles, CA, 90033, United States
| | - Robert A Bonomo
- Department of Medicine, Pharmacology, and Molecular Biology and Microbiology, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Case Western Reserve University, Cleveland, OH, 44120, United States
| | - Brad Spellberg
- Department of Medicine and Department of Molecular Microbiology & Immunology, Keck School of Medicine at the University of Southern California (USC), Los Angeles, CA, 90033, United States
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9
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Miró-Canturri A, Ayerbe-Algaba R, Vila-Domínguez A, Jiménez-Mejías ME, Pachón J, Smani Y. Repurposing of the Tamoxifen Metabolites to Combat Infections by Multidrug-Resistant Gram-Negative Bacilli. Antibiotics (Basel) 2021; 10:336. [PMID: 33810067 PMCID: PMC8004611 DOI: 10.3390/antibiotics10030336] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 03/19/2021] [Accepted: 03/21/2021] [Indexed: 12/14/2022] Open
Abstract
The development of new strategic antimicrobial therapeutic approaches, such as drug repurposing, has become an urgent need. Previously, we reported that tamoxifen presents therapeutic efficacy against multidrug-resistant (MDR) Acinetobacter baumannii, Pseudomonas aeruginosa, and Escherichia coli in experimental infection models by modulating innate immune system cell traffic. The main objective of this study was to analyze the activity of N-desmethyltamoxifen, 4-hydroxytamoxifen, and endoxifen, three major metabolites of tamoxifen, against these pathogens. We showed that immunosuppressed mice infected with A. baumannii, P. aeruginosa, or E. coli in peritoneal sepsis models and treated with tamoxifen at 80 mg/kg/d for three days still reduced the bacterial load in tissues and blood. Moreover, it increased mice survival to 66.7% (for A. baumannii and E. coli) and 16.7% (for P. aeruginosa) when compared with immunocompetent mice. Further, susceptibility and time-kill assays showed that N-desmethyltamoxifen, 4-hydroxytamoxifen, and endoxifen exhibited minimum inhibitory concentration of the 90% of the isolates (MIC90) values of 16 mg/L, and were bactericidal against clinical isolates of A. baumannii and E. coli. This antimicrobial activity of tamoxifen metabolites paralleled an increased membrane permeability of A. baumannii and E. coli without affecting their outer membrane proteins profiles. Together, these data showed that tamoxifen metabolites presented antibacterial activity against MDR A. baumannii and E. coli, and may be a potential alternative for the treatment of infections caused by these two pathogens.
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Affiliation(s)
- Andrea Miró-Canturri
- Clinical Unit of Infectious Diseases, Microbiology and Preventive Medicine, University Hospital Virgen del Rocío, 41013 Seville, Spain; (A.M.-C.); (R.A.-A.); (A.V.-D.); (M.E.J.-M.)
- Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío, CSIC, University of Seville, 41013 Seville, Spain;
| | - Rafael Ayerbe-Algaba
- Clinical Unit of Infectious Diseases, Microbiology and Preventive Medicine, University Hospital Virgen del Rocío, 41013 Seville, Spain; (A.M.-C.); (R.A.-A.); (A.V.-D.); (M.E.J.-M.)
- Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío, CSIC, University of Seville, 41013 Seville, Spain;
| | - Andrea Vila-Domínguez
- Clinical Unit of Infectious Diseases, Microbiology and Preventive Medicine, University Hospital Virgen del Rocío, 41013 Seville, Spain; (A.M.-C.); (R.A.-A.); (A.V.-D.); (M.E.J.-M.)
- Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío, CSIC, University of Seville, 41013 Seville, Spain;
| | - Manuel E. Jiménez-Mejías
- Clinical Unit of Infectious Diseases, Microbiology and Preventive Medicine, University Hospital Virgen del Rocío, 41013 Seville, Spain; (A.M.-C.); (R.A.-A.); (A.V.-D.); (M.E.J.-M.)
- Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío, CSIC, University of Seville, 41013 Seville, Spain;
| | - Jerónimo Pachón
- Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío, CSIC, University of Seville, 41013 Seville, Spain;
- Department of Medicine, University of Seville, 41009 Seville, Spain
| | - Younes Smani
- Clinical Unit of Infectious Diseases, Microbiology and Preventive Medicine, University Hospital Virgen del Rocío, 41013 Seville, Spain; (A.M.-C.); (R.A.-A.); (A.V.-D.); (M.E.J.-M.)
- Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío, CSIC, University of Seville, 41013 Seville, Spain;
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10
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Preserving Vascular Integrity Protects Mice against Multidrug-Resistant Gram-Negative Bacterial Infection. Antimicrob Agents Chemother 2020; 64:AAC.00303-20. [PMID: 32393494 DOI: 10.1128/aac.00303-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Accepted: 05/01/2020] [Indexed: 12/29/2022] Open
Abstract
The rise in multidrug-resistant (MDR) organisms portends a serious global threat to the health care system with nearly untreatable infectious diseases, including pneumonia and its often fatal sequelae, acute respiratory distress syndrome (ARDS) and sepsis. Gram-negative bacteria (GNB), including Acinetobacter baumannii, Pseudomonas aeruginosa, and carbapenemase-producing Klebsiella pneumoniae (CPKP), are among the World Health Organization's and National Institutes of Health's high-priority MDR pathogens for targeted development of new therapies. Here, we show that stabilizing the host's vasculature by genetic deletion or pharmacological inhibition of the small GTPase ADP-ribosylation factor 6 (ARF6) increases survival rates of mice infected with A. baumannii, P. aeruginosa, and CPKP. We show that the pharmacological inhibition of ARF6-GTP phenocopies endothelium-specific Arf6 disruption in enhancing the survival of mice with A. baumannii pneumonia, suggesting that inhibition is on target. Finally, we show that the mechanism of protection elicited by these small-molecule inhibitors acts by the restoration of vascular integrity disrupted by GNB lipopolysaccharide (LPS) activation of the TLR4/MyD88/ARNO/ARF6 pathway. By targeting the host's vasculature with small-molecule inhibitors of ARF6 activation, we circumvent microbial drug resistance and provide a potential alternative/adjunctive treatment for emerging and reemerging pathogens.
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11
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Dinc G, Eren E, Kontas O, Doganay M. The efficacy of mesenchymal stem cell therapy in experimental sepsis induced by carbapenem-resistant K. pneumoniae in neutropenic mice model. Eur J Clin Microbiol Infect Dis 2020; 39:1739-1744. [PMID: 32356028 DOI: 10.1007/s10096-020-03910-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 04/13/2020] [Indexed: 12/18/2022]
Abstract
Especially in recent years, the intensive use of antibiotics has caused multiple drug resistance in Klebsiella pneumoniae. In the absence of a new antibiotic, alternative treatment options have emerged. The aim of this study was to investigate the efficacy of mesenchymal stem cell (MSC) treatment of carbapenem-resistant K. pneumoniae sepsis in neutropenic murine model. BALB-c mice were divided into two groups as control (positive and negative) and treatment groups (colistin, colistin + MSC, MSC) after the development of neutropenia with cyclophosphamide. Sepsis was developed in mice by intraperitoneal injection of carbapenem-resistant K. pneumoniae. Three hours after inoculation of the bacteria, colistin and MSC were given in the treatment groups intraperitoneally. Colistin injection was repeated every 12 h, while MSC was administered as 2nd dose after 48 h. Mice were sacrificed at 48 and 96 h. The right lung and half of the liver were quantitatively cultured, and the bacterial load was calculated as cfu/g. The left lung, the other half of the liver tissue, and both kidneys were evaluated histopathologically. IL-6 and TNF-α cytokine levels in mouse sera were determined by ELISA. Bacterial loads in lung and liver tissues of neutropenic mice were lower in the MSC + colistin-treated group at 48 and 96 h compared to colistin and MSC monotherapy groups. Also, bacterial eradication was started the earliest in MSC + colistin group. It was concluded that combining colistin with MSC provided improved therapeutic effects compared to colistin or MSC monotherapy.
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Affiliation(s)
- Gokcen Dinc
- Department of Medical Microbiology, Faculty of Medicine, Erciyes University, 38039, Kayseri, Turkey. .,Department of Molecular Microbiology, Genome and Stem Cell Centre, Erciyes University, Kayseri, Turkey.
| | - Esma Eren
- Department of Infectious Diseases and Clinical Microbiology, Kayseri City Hospital, Kayseri, Turkey
| | - Olgun Kontas
- Department of Medical Pathology, Faculty of Medicine, Erciyes University, Kayseri, Turkey
| | - Mehmet Doganay
- Department of Infectious Diseases and Clinical Microbiology, Faculty of Medicine, Erciyes University, Kayseri, Turkey
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12
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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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13
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Harris G, KuoLee R, Xu HH, Chen W. Acute intraperitoneal infection with a hypervirulent Acinetobacter baumannii isolate in mice. Sci Rep 2019; 9:6538. [PMID: 31024025 PMCID: PMC6484084 DOI: 10.1038/s41598-019-43000-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 04/09/2019] [Indexed: 12/05/2022] Open
Abstract
Acinetobacter baumannii infection has become a major cause of healthcare-associated infection and a critical pathogen in the WHO antimicrobial resistance research and development priority list. Catheter-related septicemia is one of the major clinical manifestations of A. baumannii infection associated with high morbidity and mortality. In this study, we used a clinical A. baumannii strain (LAC-4) that is hypervirulent to immunocompetent C57BL/6 and BALB/c mice and established a mouse model of intraperitoneal (i.p.) A. baumannii infection. Our study showed that i.p. LAC-4 infection of C57BL/6 and BALB/c mice induces a lethal or sublethal infection with high bacterial burdens in peritoneal cavity, blood and tissues and the infected mice either succumbed to the infection within 24 hours or completely recovered from the infection. The infection induces acute peritoneal recruitment of neutrophils and other innate immune cells, and the local and systemic production of proinflammatory cytokines and chemokines (IL-1β, IL-5, IL-6, TNF-α, RANTES, MIP-1β, MCP-1, KC and IL-10). Mechanistic studies suggest an important role of macrophages in the host innate defense in this model in that in vitro stimulation of peritoneal macrophages with killed LAC-4 induced a similar pattern of cytokine/chemokine responses to those in the infected mice, and depletion of peritoneal macrophages rendered the mice significantly more susceptible to the infection. Thus, this mouse infection model will provide an alternative and useful tool for future pathogenesis studies of A. baumannii-associated septicemia and identification and characterization of important virulence factors, as well as serve as a surrogate model for rapid evaluation of novel therapeutics and vaccines for this emerging infectious agent.
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Affiliation(s)
- Greg Harris
- Human Health Therapeutics Research Center, National Research Council Canada, 100 Sussex Drive, Ottawa, Ontario, K1A 0R6, Canada
| | - Rhonda KuoLee
- Human Health Therapeutics Research Center, National Research Council Canada, 100 Sussex Drive, Ottawa, Ontario, K1A 0R6, Canada
| | - H Howard Xu
- Department of Biological Sciences, California State University, Los Angeles, Los Angeles, CA, 90032, USA
| | - Wangxue Chen
- Human Health Therapeutics Research Center, National Research Council Canada, 100 Sussex Drive, Ottawa, Ontario, K1A 0R6, Canada. .,Department of Biology, Brock University, St. Catharines, Ontario, L2S 3A1, Canada.
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14
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Ibrahim ME. Prevalence of Acinetobacter baumannii in Saudi Arabia: risk factors, antimicrobial resistance patterns and mechanisms of carbapenem resistance. Ann Clin Microbiol Antimicrob 2019; 18:1. [PMID: 30606201 PMCID: PMC6317247 DOI: 10.1186/s12941-018-0301-x] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 12/26/2018] [Indexed: 01/16/2023] Open
Abstract
Acinetobacter baumannii is an important opportunistic pathogen due to its capabilities for developing mechanisms of resistance to a wide range of antimicrobial agents including carbapenems. This review described the risk factors, antimicrobial susceptibility and mechanisms of carbapenem resistance of A. baumannii from different geographical regions of Saudi Arabia. Several factors including complexity of intensive care unit (ICU) environments, increased numbers of patients with serious diseases, wide spread gastrointestinal colonization and extensive use of antimicrobial drugs led to a wide prevalence of A. baumannii infections in hospitals in Saudi Arabia. A. baumannii has been noted to be less susceptible to antimicrobials agents, including carbapenems, over time, resulting in the evolution of multidrug-resistant (MDR) strains. Dissemination of MDR A. baumannii is attributed to the extreme use of wide-spectrum antimicrobial drugs in hospitals, cross infection between inpatients, invasive ICU procedures, and hospitalized patients with diabetic and cancer those are under frequent invasive diagnostic and therapeutic interventions. Although an increasing prevalence of colistin and tigecycline resistance has been reported in many hospitals, combinations of these agents with carbapenems or other antibiotics remain the best therapeutic choice and reasonably safe to treat patients with MDR A. baumannii infections. The wide distribution of carbapenem resistant A. baumannii (CRAB) due to several mechanisms with diverse genetic determinants has been documented. Although OXA-23 β-lactamase and OXA-51 β-lactamase are the most common genes responsible for CRAB, other novel genes such as blaVIM, PER-1-like and GES-5 have been discovered in carbapenem resistant strains. The high rates of MDR A. baumannii in Saudi hospitals indicate that extensive investigation into the molecular basis of MDR and developing new therapies of CRAB is needed. Moreover, the development of a local antibiogram database coupled with a nationwide antimicrobial stewardship and infection prevention program might help to improve our knowledge of the resistance patterns of A. baumannii, and in developing a treatment protocol for decreasing the infection burden in Saudi Arabia.
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Affiliation(s)
- Mutasim E Ibrahim
- Department of Basic Medical Science, College of Medicine, University of Bisha, Bisha, Saudi Arabia.
- Unit of Medical Microbiology, College of Medicine, University of Bisha, P. O. Box 731, Bisha, 61922, Saudi Arabia.
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15
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Zurawski DV, Black CC, Alamneh YA, Biggemann L, Banerjee J, Thompson MG, Wise MC, Honnold CL, Kim RK, Paranavitana C, Shearer JP, Tyner SD, Demons ST. A Porcine Wound Model of Acinetobacter baumannii Infection. Adv Wound Care (New Rochelle) 2019; 8:14-27. [PMID: 30705786 PMCID: PMC6350066 DOI: 10.1089/wound.2018.0786] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 06/24/2018] [Indexed: 01/25/2023] Open
Abstract
Objective: To better understand Acinetobacter baumannii pathogenesis and to advance drug discovery against this pathogen, we developed a porcine, full-thickness, excisional, monospecies infection wound model. Approach: The research was facilitated with AB5075, a previously characterized, extensively drug-resistant A. baumannii isolate. The model requires cyclophosphamide-induced neutropenia to establish a skin and soft tissue infection (SSTI) that persists beyond 7 days. Multiple, 12-mm-diameter full-thickness wounds were created in the skin overlying the cervical and thoracic dorsum. Wound beds were inoculated with 5.0 × 104 colony-forming units (CFU) and covered with dressing. Results:A. baumannii was observed in the wound bed and on the dressing in what appeared to be biofilm. When bacterial burdens were measured, proliferation to at least 106 CFU/g (log106) wound tissue was observed. Infection was further characterized by scanning electron microscopy (SEM) and peptide nucleic acid fluorescence in situ hybridization (PNA-FISH) staining. To validate as a treatment model, polymyxin B was applied topically to a subset of infected wounds every 2 days. Then, the treated and untreated wounds were compared using multiple quantitative and qualitative techniques to include gross pathology, CFU burden, histopathology, PNA-FISH, and SEM. Innovation: This is the first study to use A. baumannii in a porcine model as the sole infectious agent. Conclusion: The porcine model allows for an additional preclinical assessment of antibacterial candidates that show promise against A. baumannii in rodent models, further evaluating safety and efficacy, and serve as a large animal in preclinical assessment for the treatment of SSTI.
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Affiliation(s)
- Daniel V. Zurawski
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Chad C. Black
- Experimental Therapeutics Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Yonas A. Alamneh
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Lionel Biggemann
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Jaideep Banerjee
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Mitchell G. Thompson
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Matthew C. Wise
- Veterinary Services Program, Department of Pathology, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Cary L. Honnold
- Veterinary Services Program, Department of Pathology, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Robert K. Kim
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Chrysanthi Paranavitana
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Jonathan P. Shearer
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Stuart D. Tyner
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Samandra T. Demons
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland
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16
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Uppuluri P, Lin L, Alqarihi A, Luo G, Youssef EG, Alkhazraji S, Yount NY, Ibrahim BA, Bolaris MA, Edwards JE, Swidergall M, Filler SG, Yeaman MR, Ibrahim AS. The Hyr1 protein from the fungus Candida albicans is a cross kingdom immunotherapeutic target for Acinetobacter bacterial infection. PLoS Pathog 2018; 14:e1007056. [PMID: 29746596 PMCID: PMC5963808 DOI: 10.1371/journal.ppat.1007056] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 05/22/2018] [Accepted: 04/26/2018] [Indexed: 11/21/2022] Open
Abstract
Different pathogens share similar medical settings and rely on similar virulence strategies to cause infections. We have previously applied 3-D computational modeling and bioinformatics to discover novel antigens that target more than one human pathogen. Active and passive immunization with the recombinant N-terminus of Candida albicans Hyr1 (rHyr1p-N) protect mice against lethal candidemia. Here we determine that Hyr1p shares homology with cell surface proteins of the multidrug resistant Gram negative bacterium, Acinetobacter baumannii including hemagglutinin (FhaB) and outer membrane protein A (OmpA). The A. baumannii OmpA binds to C. albicans Hyr1p, leading to a mixed species biofilm. Deletion of HYR1, or blocking of Hyr1p using polyclonal antibodies, significantly reduce A. baumannii binding to C. albicans hyphae. Furthermore, active vaccination with rHyr1p-N or passive immunization with polyclonal antibodies raised against specific peptide motifs of rHyr1p-N markedly improve survival of diabetic or neutropenic mice infected with A. baumannii bacteremia or pneumonia. Antibody raised against one particular peptide of the rHyr1p-N sequence (peptide 5) confers majority of the protection through blocking A. baumannii invasion of host cells and inducing death of the bacterium by a putative iron starvation mechanism. Anti-Hyr1 peptide 5 antibodies also mitigate A. baumannii /C. albicans mixed biofilm formation in vitro. Consistent with our bioinformatic analysis and structural modeling of Hyr1p, anti-Hyr1p peptide 5 antibodies bound to A. baumannii FhaB, OmpA, and an outer membrane siderophore binding protein. Our studies highlight the concept of cross-kingdom vaccine protection against high priority human pathogens such as A. baumannii and C. albicans that share similar ecological niches in immunocompromised patients.
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Affiliation(s)
- Priya Uppuluri
- Department of Medicine, Los Angeles Biomedical Research Institute at Harbor-University of California at Los Angeles (UCLA) Medical Center, Torrance, California, United States of America
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America
| | - Lin Lin
- Department of Medicine, Los Angeles Biomedical Research Institute at Harbor-University of California at Los Angeles (UCLA) Medical Center, Torrance, California, United States of America
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America
| | - Abdullah Alqarihi
- Department of Medicine, Los Angeles Biomedical Research Institute at Harbor-University of California at Los Angeles (UCLA) Medical Center, Torrance, California, United States of America
| | - Guanpingsheng Luo
- Department of Medicine, Los Angeles Biomedical Research Institute at Harbor-University of California at Los Angeles (UCLA) Medical Center, Torrance, California, United States of America
| | - Eman G. Youssef
- Department of Medicine, Los Angeles Biomedical Research Institute at Harbor-University of California at Los Angeles (UCLA) Medical Center, Torrance, California, United States of America
- Department of Biotechnology and Life Sciences, Faculty of Postgraduate Studies for Advanced Sciences (PSAS), Beni-Suef University, Beni-Suef, Egypt
| | - Sondus Alkhazraji
- Department of Medicine, Los Angeles Biomedical Research Institute at Harbor-University of California at Los Angeles (UCLA) Medical Center, Torrance, California, United States of America
| | - Nannette Y. Yount
- Department of Medicine, Los Angeles Biomedical Research Institute at Harbor-University of California at Los Angeles (UCLA) Medical Center, Torrance, California, United States of America
| | - Belal A. Ibrahim
- Portola High School, Irvine, California, United States of America
| | - Michael Anthony Bolaris
- Department of Medicine, Los Angeles Biomedical Research Institute at Harbor-University of California at Los Angeles (UCLA) Medical Center, Torrance, California, United States of America
| | - John E. Edwards
- Department of Medicine, Los Angeles Biomedical Research Institute at Harbor-University of California at Los Angeles (UCLA) Medical Center, Torrance, California, United States of America
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America
| | - Marc Swidergall
- Department of Medicine, Los Angeles Biomedical Research Institute at Harbor-University of California at Los Angeles (UCLA) Medical Center, Torrance, California, United States of America
| | - Scott G. Filler
- Department of Medicine, Los Angeles Biomedical Research Institute at Harbor-University of California at Los Angeles (UCLA) Medical Center, Torrance, California, United States of America
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America
| | - Michael R. Yeaman
- Department of Medicine, Los Angeles Biomedical Research Institute at Harbor-University of California at Los Angeles (UCLA) Medical Center, Torrance, California, United States of America
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America
| | - Ashraf S. Ibrahim
- Department of Medicine, Los Angeles Biomedical Research Institute at Harbor-University of California at Los Angeles (UCLA) Medical Center, Torrance, California, United States of America
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America
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17
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Hu C, Jiang J, Li Z, Li Y. Expression pattern of soluble triggering receptor expressed on myeloid cells-1 in mice with Acinetobacter baumannii colonization and infection in the lung. J Thorac Dis 2018; 10:1614-1621. [PMID: 29707313 DOI: 10.21037/jtd.2018.03.41] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Background Acinetobacter baumannii (A. baumannii) is one of the most troublesome opportunistic pathogens associated with hospital-acquired pneumonia (HAP). It is important to be able to discriminate A. baumannii colonization from infection in its early stages so that effective antibiotics can be promptly applied. Recent studies have reported that the secretion of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) is markedly upregulated in pneumonia and sepsis, but the expression pattern of sTREM-1 in A. baumannii colonization and infection in the lung has not been explored. Methods C57BL/6J male mice were intraperitoneally injected with 1% streptozotocin for 5 consecutive days to establish diabetic models. Subsequently, aerosol inhalation of A. baumannii suspension was performed in these mice to induce pulmonary colonization or infection with saline as vehicle control. Mice were sacrificed and lung tissue was harvested on days 0, 1, 3, 5 and 7 after exposure. Pharyngeal swab culture, lung homogenate culture, and H&E staining of lung tissue were performed to assess the severity of infectious inflammation. sTREM-1 expressions in serum and lung supernatants, serum procalcitonin (PCT) and C-reactive protein (CRP) concentrations were measured by ELISA. Results A. baumannii colonization and infection models were verified by pharyngeal swab culture, lung homogenate culture, and H&E staining. While sTREM-1 concentrations in mice with A. baumannii colonization remained unchanged in serum and lung supernatants, sTREM-1 expression levels in infected animals were significantly upregulated. In addition, serum sTREM-1 concentration was positively correlated with serum levels of PCT and CRP. Conclusions Dynamic secretion of sTREM-1 is associated with the development of A. baumannii infection in the lung. Therefore, sTREM-1 expression level may be a promising biomarker for discriminating A. baumannii infection from colonization.
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Affiliation(s)
- Chengping Hu
- Department of Respiratory Medicine (Department of Respiratory and Critical Care Medicine), Key Cite of National Clinical Research Center for Respiratory Disease, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Juan Jiang
- Department of Respiratory Medicine (Department of Respiratory and Critical Care Medicine), Key Cite of National Clinical Research Center for Respiratory Disease, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Zhen Li
- Department of Respiratory Medicine (Department of Respiratory and Critical Care Medicine), Key Cite of National Clinical Research Center for Respiratory Disease, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Yuanyuan Li
- Department of Respiratory Medicine (Department of Respiratory and Critical Care Medicine), Key Cite of National Clinical Research Center for Respiratory Disease, Xiangya Hospital, Central South University, Changsha 410008, China
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18
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Shi H, Zhu J, Zou B, Shi L, Du L, Long Y, Wang H, Xu H, Zhen Y, Sun L. Effects of specific egg yolk immunoglobulin on pan-drug-resistant Acinetobacter baumannii. Biomed Pharmacother 2017; 95:1734-1742. [PMID: 28962078 PMCID: PMC7126593 DOI: 10.1016/j.biopha.2017.09.112] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 09/20/2017] [Accepted: 09/20/2017] [Indexed: 01/02/2023] Open
Abstract
With the growing emergence of
pan-drug-resistant Acinetobacter baumannii
(PDR-Ab) strains in clinical, new strategies for the treatment of PDR-Ab
infections are urgently needed. Egg yolk immunoglobulin (IgY) as a
convenient and inexpensive antibody has been widely applied to the
therapy of infectious diseases. The aim of this study was to produce IgY
specific to PDR-Ab and investigate its antibacterial effects
in vitro and in vivo.
IgYs specific to two PDR-Ab strains were produced by immunizing hens with
formaldehyde inactivated PDR-Ab cells and isolated from yolks with a
purity of 90% by water dilution, salt precipitations and ultrafiltration.
IgYs showed high titers when subjected to an ELISA and inhibited the
growth of PDR-Ab in a dose-dependent manner in liquid medium. Scanning
electron microscopy assay showed structural modification and aggregation
of PDR-Ab treated with specific IgYs. Freshly cultured PDR-Ab cells were
nasally inhaled in BALB/c mice to induce acute pneumonia. The infected
mice were intraperitoneally injected with specific IgYs using
cefoperazone/sulbactam and dexamethasone as positive controls. The IgYs
specific to PDR-Ab lowered the mortality of mice with PDR-Ab-induced
acute pneumonia, decreased the level of TNF-α and IL-1β in serum and
reduced inflammation in lung tissue. Specific IgY has the potential to be
used as a new therapeutic approach for the treatment of A.
baumannii-induced infections.
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Affiliation(s)
- Huaying Shi
- Affiliated Dalian Friendship Hospital of Dalian Medical University, Dalian, 116001, China
| | - Jie Zhu
- The Second Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, 116021, China
| | - Boyang Zou
- College of Pharmacy, Dalian Medical University, Dalian, 116044, China
| | - Lei Shi
- College of Pharmacy, Dalian Medical University, Dalian, 116044, China
| | - Linying Du
- College of Pharmacy, Dalian Medical University, Dalian, 116044, China
| | - Yayi Long
- College of Pharmacy, Dalian Medical University, Dalian, 116044, China
| | - Huaxin Wang
- College of Basic Medical Sciences, Dalian Medical University, Dalian, 116044, China
| | - Hong Xu
- College of Basic Medical Sciences, Dalian Medical University, Dalian, 116044, China
| | - Yuhong Zhen
- College of Pharmacy, Dalian Medical University, Dalian, 116044, China.
| | - Lidan Sun
- Affiliated Dalian Friendship Hospital of Dalian Medical University, Dalian, 116001, China.
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A Human Biofilm-Disrupting Monoclonal Antibody Potentiates Antibiotic Efficacy in Rodent Models of both Staphylococcus aureus and Acinetobacter baumannii Infections. Antimicrob Agents Chemother 2017; 61:AAC.00904-17. [PMID: 28717038 DOI: 10.1128/aac.00904-17] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 07/11/2017] [Indexed: 12/22/2022] Open
Abstract
Many serious bacterial infections are antibiotic refractory due to biofilm formation. A key structural component of biofilm is extracellular DNA, which is stabilized by bacterial proteins, including those from the DNABII family. TRL1068 is a high-affinity human monoclonal antibody against a DNABII epitope conserved across both Gram-positive and Gram-negative bacterial species. In the present study, the efficacy of TRL1068 for the disruption of biofilm was demonstrated in vitro in the absence of antibiotics by scanning electron microscopy. The in vivo efficacy of this antibody was investigated in a well-characterized catheter-induced aortic valve infective endocarditis model in rats infected with a methicillin-resistant Staphylococcus aureus (MRSA) strain with the ability to form thick biofilms, obtained from the blood of a patient with persistent clinical infection. Animals were treated with vancomycin alone or in combination with TRL1068. MRSA burdens in cardiac vegetations and within intracardiac catheters, kidneys, spleen, and liver showed significant reductions in the combination arm versus vancomycin alone (P < 0.001). A trend toward mortality reduction was also observed (P = 0.09). In parallel, the in vivo efficacy of TRL1068 against a multidrug-resistant clinical Acinetobacter baumannii isolate was explored by using an established mouse model of skin and soft tissue catheter-related biofilm infection. Catheter segments infected with A. baumannii were implanted subcutaneously into mice; animals were treated with imipenem alone or in combination with TRL1068. The combination showed a significant reduction of catheter-adherent bacteria versus the antibiotic alone (P < 0.001). TRL1068 shows excellent promise as an adjunct to standard-of-care antibiotics for a broad range of difficult-to-treat bacterial infections.
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20
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Clinical and Pathophysiological Overview of Acinetobacter Infections: a Century of Challenges. Clin Microbiol Rev 2017; 30:409-447. [PMID: 27974412 DOI: 10.1128/cmr.00058-16] [Citation(s) in RCA: 634] [Impact Index Per Article: 90.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Acinetobacter is a complex genus, and historically, there has been confusion about the existence of multiple species. The species commonly cause nosocomial infections, predominantly aspiration pneumonia and catheter-associated bacteremia, but can also cause soft tissue and urinary tract infections. Community-acquired infections by Acinetobacter spp. are increasingly reported. Transmission of Acinetobacter and subsequent disease is facilitated by the organism's environmental tenacity, resistance to desiccation, and evasion of host immunity. The virulence properties demonstrated by Acinetobacter spp. primarily stem from evasion of rapid clearance by the innate immune system, effectively enabling high bacterial density that triggers lipopolysaccharide (LPS)-Toll-like receptor 4 (TLR4)-mediated sepsis. Capsular polysaccharide is a critical virulence factor that enables immune evasion, while LPS triggers septic shock. However, the primary driver of clinical outcome is antibiotic resistance. Administration of initially effective therapy is key to improving survival, reducing 30-day mortality threefold. Regrettably, due to the high frequency of this organism having an extreme drug resistance (XDR) phenotype, early initiation of effective therapy is a major clinical challenge. Given its high rate of antibiotic resistance and abysmal outcomes (up to 70% mortality rate from infections caused by XDR strains in some case series), new preventative and therapeutic options for Acinetobacter spp. are desperately needed.
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Abstract
For more than a century, diabetic patients have been considered immunosuppressed due to defects in phagocytosis and microbial killing. We confirmed that diabetic mice were hypersusceptible to bacteremia caused by Gram-negative bacteria (GNB), dying at inocula nonlethal to nondiabetic mice. Contrary to the pervasive paradigm that diabetes impedes phagocytic function, the bacterial burden was no greater in diabetic mice despite excess mortality. However, diabetic mice did exhibit dramatically increased levels of proinflammatory cytokines in response to GNB infections, and immunosuppressing these cytokines with dexamethasone restored their resistance to infection, both of which are consistent with excess inflammation. Furthermore, disruption of the receptor for advanced glycation end products (RAGE), which is stimulated by heightened levels of AGEs in diabetic hosts, protected diabetic but not nondiabetic mice from GNB infection. Thus, rather than immunosuppression, diabetes drives lethal hyperinflammation in response to GNB by signaling through RAGE. As such, interventions to improve the outcomes from GNB infections should seek to suppress the immune response in diabetic hosts. Physicians and scientists have subscribed to the dogma that diabetes predisposes the host to worse outcomes from infections because it suppresses the immune system. This understanding was based largely on ex vivo studies of blood from patients and animals with diabetes. However, we have found that the opposite is true and worse outcomes from infection are caused by overstimulation of the immune system in response to bacteria. This overreaction occurs by simultaneous ligation of two host receptors: TLR4 and RAGE. Both signal via a common downstream messenger, MyD88, triggering hyperinflammation. In summary, contrary to hundred-year-old postulations about immune suppression in diabetic hosts, we find that diabetes instead predisposes to more severe infections because of additional inflammatory output through dual activation of MyD88 by not only TLR4 but also RAGE. It is the activation of RAGE during GNB infections in those with diabetes that accounts for their heightened susceptibility to infection compared to nondiabetic hosts.
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22
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Harris G, KuoLee R, Xu HH, Chen W. Mouse Models of Acinetobacter baumannii Infection. ACTA ACUST UNITED AC 2017; 46:6G.3.1-6G.3.23. [PMID: 28800159 DOI: 10.1002/cpmc.36] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
This unit describes basic protocols for infecting mice through intranasal and intraperitoneal routes with Acinetobacter baumannii to induce associated pneumonia and sepsis, the two most common manifestations of clinical infections with this pathogen. By selecting the appropriate protocols and bacterial strains of different virulence, these mouse models provide an opportunity to study the infection pathogenesis and host-immune responses, and to evaluate the efficacies of prophylactic and therapeutic anti-A. baumannii candidates. © 2017 by John Wiley & Sons, Inc.
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Affiliation(s)
- Greg Harris
- Human Health and Therapeutics, National Research Council Canada, Ottawa, Ontario, Canada
| | - Rhonda KuoLee
- Human Health and Therapeutics, National Research Council Canada, Ottawa, Ontario, Canada
| | - H Howard Xu
- Department of Biological Sciences, California State University, Los Angeles, California
| | - Wangxue Chen
- Human Health and Therapeutics, National Research Council Canada, Ottawa, Ontario, Canada.,Department of Biological Sciences, Brock University, St. Catharines, Ontario, Canada
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García-Patiño MG, García-Contreras R, Licona-Limón P. The Immune Response against Acinetobacter baumannii, an Emerging Pathogen in Nosocomial Infections. Front Immunol 2017; 8:441. [PMID: 28446911 PMCID: PMC5388700 DOI: 10.3389/fimmu.2017.00441] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 03/29/2017] [Indexed: 12/18/2022] Open
Abstract
Acinetobacter baumannii is the etiologic agent of a wide range of nosocomial infections, including pneumonia, bacteremia, and skin infections. Over the last 45 years, an alarming increase in the antibiotic resistance of this opportunistic microorganism has been reported, a situation that hinders effective treatments. In order to develop effective therapies against A. baumannii it is crucial to understand the basis of host–bacterium interactions, especially those concerning the immune response of the host. Different innate immune cells such as monocytes, macrophages, dendritic cells, and natural killer cells have been identified as important effectors in the defense against A. baumannii; among them, neutrophils represent a key immune cell indispensable for the control of the infection. Several immune strategies to combat A. baumannii have been identified such as recognition of the bacteria by immune cells through pattern recognition receptors, specifically toll-like receptors, which trigger bactericidal mechanisms including oxidative burst and cytokine and chemokine production to amplify the immune response against the pathogen. However, a complete picture of the protective immune strategies activated by this bacteria and its potential therapeutic use remains to be determined and explored.
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Affiliation(s)
- María Guadalupe García-Patiño
- Departamento de Biología Celular y del Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Rodolfo García-Contreras
- Facultad de Medicina, Departamento de Microbiología y Parasitología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Paula Licona-Limón
- Departamento de Biología Celular y del Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
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24
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Park JY, Park C, Chun HS, Byun JH, Cho SY, Lee DG. Establishment of Experimental Murine Peritonitis Model with Hog Gastric Mucin for Carbapenem-Resistant Gram-Negative Bacteria. Infect Chemother 2017; 49:57-61. [PMID: 28271653 PMCID: PMC5382051 DOI: 10.3947/ic.2017.49.1.57] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 01/17/2017] [Indexed: 01/21/2023] Open
Abstract
Animal models are essential to studies of infectious diseases. The use of mice to test bacterial infection has been extensively reported. However, methods applied to clinical isolates, particularly for carbapenem-resistant bacteria, must be tailored according to the infection models and bacteria used. In this study, we infected 6-week-old female BALB/c mice intraperitoneally with different strains of resistant bacteria plus 3% hog gastric mucin. This method was found to be efficient and readily applicable for investigation of carbapenem-resisant Gram-negative pathogens (e.g., Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii) detected in Korea.
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Affiliation(s)
- Jung Yeon Park
- Vaccine Bio Research Institute, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Chulmin Park
- Vaccine Bio Research Institute, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Hye Sun Chun
- Vaccine Bio Research Institute, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Ji Hyun Byun
- Vaccine Bio Research Institute, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Sung Yeon Cho
- Vaccine Bio Research Institute, College of Medicine, The Catholic University of Korea, Seoul, Korea
- Division of Infectious Diseases, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Dong Gun Lee
- Vaccine Bio Research Institute, College of Medicine, The Catholic University of Korea, Seoul, Korea
- Division of Infectious Diseases, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
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25
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Wang Y, Zhang X, Feng X, Liu X, Deng L, Liang ZA. Expression of Toll-like receptor 4 in lungs of immune-suppressed rat with Acinetobacter baumannii infection. Exp Ther Med 2016; 12:2599-2605. [PMID: 27703512 PMCID: PMC5038893 DOI: 10.3892/etm.2016.3624] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 08/18/2016] [Indexed: 02/05/2023] Open
Abstract
Toll-like receptor 4 (TLR4) is involved in the regulation of host responses to Acinetobacter baumannii (A. baumannii). The aim of the present study was to examine the function of TLR4 in lung inflammation in immune-suppressed rats with A. baumannii infection. A total of 72 Sprague-Dawley male rats were randomly divided into the control, A. baumannii infection and immune-suppressed infection groups. The immune-suppressed infection group was treated with 100 mg/kg hydrocortisone by subcutaneous injection every other day for 2 weeks prior to A. baumannii infection. Lung tissue was obtained on the 3rd and 7th day after tracheal inoculation with A. baumannii. The expression of TLR4 in bronchial and alveolar epithelial cells, and alveolar macrophage was examined using immunohistochemistry. The levels of interleukin (IL)-6, tumor necrosis factor (TNF)-α in bronchoalveolar lavage fluid were detected using ELISA. The results showed that in the control group, the expression of TLR4 was upregulated in the bronchial and alveolar epithelial, and alveolar macrophages, and the levels of IL-6 and TNF-α were increased in the early phase of A. baumannii infection. On the 7th day, no significant difference in the levels of IL-6 and TNF-α was observed between the A. baumannii infection and control groups. Conversely, the expression of TLR4 was downregulated in the immune-suppressed group, and the levels of IL-6 and TNF-α were reduced on the 3rd day after infection. In the subsequent observation period, the expression of TLR4 was upregulated and the levels of IL-6 and TNF-α were increased. In conclusion, the results show a critical role of TLR4 in mediating effective immune response in the lung of rat with A. baumannii infection.
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Affiliation(s)
- Yanmei Wang
- Department of Intensive Care Unit, Sichuan Second Hospital of Traditional Chinese Medicine, Chengdu, Sichuan 610031, P.R. China
| | - Xiaohong Zhang
- Department of Emergency Intensive Care Unit, Sichuan Academy of Medical Sciences and Sichuan Province People's Hospital, Chengdu, Sichuan 610072, P.R. China
| | - Xuanlin Feng
- Department of Emergency Intensive Care Unit, Sichuan Academy of Medical Sciences and Sichuan Province People's Hospital, Chengdu, Sichuan 610072, P.R. China
| | - Xiaoshu Liu
- Department of Emergency Intensive Care Unit, Sichuan Academy of Medical Sciences and Sichuan Province People's Hospital, Chengdu, Sichuan 610072, P.R. China
| | - Lei Deng
- Department of Emergency Intensive Care Unit, Sichuan Academy of Medical Sciences and Sichuan Province People's Hospital, Chengdu, Sichuan 610072, P.R. China
| | - Zong-An Liang
- Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, P.R. China
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26
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Protective Effect of a Synbiotic against Multidrug-Resistant Acinetobacter baumannii in a Murine Infection Model. Antimicrob Agents Chemother 2016; 60:3041-50. [PMID: 26953197 DOI: 10.1128/aac.02928-15] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 03/02/2016] [Indexed: 12/17/2022] Open
Abstract
This study investigated the ability of the probiotic Bifidobacterium breve strain Yakult (BbY) to protect against infection, as well as the potentiation of BbY activity by the synbiotic combination of BbY and prebiotic galactooligosaccharides (GOS). The study employed a mouse model of lethal intestinal multidrug-resistant Acinetobacter baumannii (MDRAb) infection. The endogenous intestinal microbiota was disrupted by the administration of multiple antibiotics, causing the loss of endogenous Bifidobacterium Oral infection of these mice with MDRAb resulted in marked growth of this organism. Additional treatment of the infected mice with a sublethal dose of 5-fluorouracil (5-FU) induced systemic invasion by MDRAb and subsequent animal death. The continuous oral administration of BbY increased the survival rate and inhibited the intestinal growth and invasion by MDRAb in the infection model. Disruptions of the intestinal environment and barrier function in the infected mice were attenuated by BbY. Protection against the MDRAb infection was markedly potentiated by a synbiotic combination of BbY and GOS, although GOS by itself did not provide protection. Negative correlations were observed between intestinal MDRAb and BbY counts or acetic acid levels; positive correlations were observed between acetic acid levels and intestinal epithelium expression of tight-junction-related genes. These results demonstrated that the probiotic and synbiotic markedly potentiated protection against fatal intestinal infection caused by a multidrug-resistant bacterium. Probiotics and synbiotics are presumed to provide protection by compensation for the disrupted indigenous populations, thereby maintaining the intestinal environments and barrier functions otherwise targeted during opportunistic infection by MDRAb.
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El-Shazly S, Dashti A, Vali L, Bolaris M, Ibrahim AS. Molecular epidemiology and characterization of multiple drug-resistant (MDR) clinical isolates of Acinetobacter baumannii. Int J Infect Dis 2015; 41:42-9. [PMID: 26518066 DOI: 10.1016/j.ijid.2015.10.016] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Revised: 10/05/2015] [Accepted: 10/22/2015] [Indexed: 01/17/2023] Open
Abstract
OBJECTIVES The aim of this study was to identify the genetic relatedness of multiple drug-resistant (MDR) Acinetobacter baumannii clinical isolates recovered from a hospital in Los Angeles. METHODS Twenty-one MDR A. baumannii isolates were collected and their antibiotic susceptibilities determined according to Clinical and Laboratory Standards Institute guidelines. Genes coding for antibiotic resistance were identified by PCR, and their identities were confirmed by DNA sequencing. Clonal relationships were studied by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). RESULTS MDR consistently correlated with the presence of oxacillinases, mostly in the form of the plasmid-mediated OXA-23 enzyme, which was detected in 12 (57.1%) isolates. GES-type carbapenemases were found in 20 (95.2%) strains, AAC in all 21 (100%) strains, and PER in seven (33.3%) strains, and ISAba1 was detected in 16 (76.2%) isolates. The association between ISAba1 and resistance genes confirms insertion elements as a source of β-lactamase production. Of the 21 clinical isolates, five were found to be related to sequence type 1 (ST1) and 16 to ST2, as analyzed by MLST. PFGE demonstrated that the majority of clinical isolates were highly related (>85%). CONCLUSIONS This study supports a more complete understanding of genotyping of antibiotic resistance for better assessment of MDR strain transmission.
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Affiliation(s)
- Sherief El-Shazly
- Department of Medical Laboratory Sciences, Faculty of Allied Health Sciences, Health Sciences Center, Kuwait University, Kuwait; Division of Adult Infectious Diseases, Los Angeles Biomedical Research Institute at Harbor-University of California Los Angeles (UCLA) Medical Center, 1124 West Carson St., St. John's Cardiovascular Research Center, Torrance, CA 90502, USA
| | - Ali Dashti
- Department of Medical Laboratory Sciences, Faculty of Allied Health Sciences, Health Sciences Center, Kuwait University, Kuwait
| | - Leila Vali
- Department of Medical Laboratory Sciences, Faculty of Allied Health Sciences, Health Sciences Center, Kuwait University, Kuwait
| | - Michael Bolaris
- Division of Pediatric Infectious Diseases, Los Angeles Biomedical Research Institute at Harbor-University of California Los Angeles (UCLA) Medical Center, Torrance, California, USA
| | - Ashraf S Ibrahim
- Division of Adult Infectious Diseases, Los Angeles Biomedical Research Institute at Harbor-University of California Los Angeles (UCLA) Medical Center, 1124 West Carson St., St. John's Cardiovascular Research Center, Torrance, CA 90502, USA; David Geffen School of Medicine at UCLA, Los Angeles, California, USA.
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28
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Jones CL, Clancy M, Honnold C, Singh S, Snesrud E, Onmus-Leone F, McGann P, Ong AC, Kwak Y, Waterman P, Zurawski DV, Clifford RJ, Lesho E. Fatal Outbreak of an Emerging Clone of Extensively Drug-ResistantAcinetobacter baumanniiWith Enhanced Virulence. Clin Infect Dis 2015; 61:145-54. [DOI: 10.1093/cid/civ225] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 12/28/2014] [Indexed: 01/17/2023] Open
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Validation of a novel murine wound model of Acinetobacter baumannii infection. Antimicrob Agents Chemother 2013; 58:1332-42. [PMID: 24342634 DOI: 10.1128/aac.01944-13] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Patients recovering from traumatic injuries or surgery often require weeks to months of hospitalization, increasing the risk for wound and surgical site infections caused by ESKAPE pathogens, which include A. baumannii (the ESKAPE pathogens are Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species). As new therapies are being developed to counter A. baumannii infections, animal models are also needed to evaluate potential treatments. Here, we present an excisional, murine wound model in which a diminutive inoculum of a clinically relevant, multidrug-resistant A. baumannii isolate can proliferate, form biofilms, and be effectively treated with antibiotics. The model requires a temporary, cyclophosphamide-induced neutropenia to establish an infection that can persist. A 6-mm-diameter, full-thickness wound was created in the skin overlying the thoracic spine, and after the wound bed was inoculated, it was covered with a dressing for 7 days. Uninoculated control wounds healed within 13 days, whereas infected, placebo-treated wounds remained unclosed beyond 21 days. Treated and untreated wounds were assessed with multiple quantitative and qualitative techniques that included gross pathology, weight loss and recovery, wound closure, bacterial burden, 16S rRNA community profiling, histopathology, peptide nucleic acid-fluorescence in situ hybridization, and scanning electron microscopy assessment of biofilms. The range of differences that we are able to identify with these measures in antibiotic- versus placebo-treated animals provides a clear window within which novel antimicrobial therapies can be assessed. The model can be used to evaluate antimicrobials for their ability to reduce specific pathogen loads in wounded tissues and clear biofilms. Ultimately, the mouse model approach allows for highly powered studies and serves as an initial multifaceted in vivo assessment prior to testing in larger animals.
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Rawat V, Singhai M, Kumar A, Jha PK, Goyal R. Bacteriological and resistance profile in isolates from diabetic patients. NORTH AMERICAN JOURNAL OF MEDICAL SCIENCES 2012; 4:563-8. [PMID: 23181227 PMCID: PMC3503374 DOI: 10.4103/1947-2714.103315] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Diabetes mellitus has become a global epidemic illness and poses a threat for development of resistant bacterial infections. AIM This study was aimed to know the bacteriological and resistance profile of isolates obtained from diabetic patients. MATERIALS AND METHODS The bacterial isolates obtained from various samples of diabetic patients admitted in medicine department in 6-month period were identified and tested for antibiotic susceptibility. The extended spectrum beta-lactamases (ESβL), AmpC, and metallo-beta-lactamases (MβL) enzymes were detected in gram-negative bacilli. Methicillin, macrolide-lincosamide-streptogramin (MLS), and linezolid resistance in Staphylococcus spp. were detected. High-level aminoglycoside resistance (HLAR) in Enterococcus spp. was also tested. RESULTS In all, 38 of 125 diabetic patients (30.4%) had bacterial infection, 18 patients had wound infections, 18 had urinary tract infections (UTIs), and 2 had respiratory tract infections. Escherichia coli among gram-negative bacteria and Staphylococcus aureus among gram-positive bacteria were the predominant pathogens. 32.5% gram-negative bacilli were AmpC producers, 37.5% were MβL producers, and 40% were ESβL producers. Methicillin and MLS resistance was found in 50% and 33.3% isolates of Staphylococcus spp., respectively. HLAR resistance was alarming in Enterococcus spp. Polymyxin among gram-negative bacteria and vancomycin for gram-positive bacteria were the last resort with highest susceptibility rates to treat infections among diabetic patients. CONCLUSION Resistant bacterial infections in diabetic patients are common. The presence of various resistance mechanisms in isolates of our study shows that therapeutic failure can occur if empirical prescription is unsubstantiated.
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Affiliation(s)
- Vinita Rawat
- Department of Microbiology, Government Medical College, Haldwani, Uttarakhand, India
| | - Monil Singhai
- Department of Microbiology, Government Medical College, Haldwani, Uttarakhand, India
| | - Ashok Kumar
- Department of Medicine, Government Medical College, Haldwani, Uttarakhand, India
| | - Pawan Kumar Jha
- Department of Surgery, Government Medical College, Haldwani, Uttarakhand, India
| | - Rajeev Goyal
- Department of Biochemistry, Government Medical College, Haldwani, Uttarakhand, India
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Inhibition of LpxC protects mice from resistant Acinetobacter baumannii by modulating inflammation and enhancing phagocytosis. mBio 2012; 3:mBio.00312-12. [PMID: 23033474 PMCID: PMC3518917 DOI: 10.1128/mbio.00312-12] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
New treatments are needed for extensively drug-resistant (XDR) Gram-negative bacilli (GNB), such as Acinetobacter baumannii. Toll-like receptor 4 (TLR4) was previously reported to enhance bacterial clearance of GNB, including A. baumannii. However, here we have shown that 100% of wild-type mice versus 0% of TLR4-deficient mice died of septic shock due to A. baumannii infection, despite having similar tissue bacterial burdens. The strain lipopolysaccharide (LPS) content and TLR4 activation by extracted LPS did not correlate with in vivo virulence, nor did colistin resistance due to LPS phosphoethanolamine modification. However, more-virulent strains shed more LPS during growth than less-virulent strains, resulting in enhanced TLR4 activation. Due to the role of LPS in A. baumannii virulence, an LpxC inhibitor (which affects lipid A biosynthesis) antibiotic was tested. The LpxC inhibitor did not inhibit growth of the bacterium (MIC > 512 µg/ml) but suppressed A. baumannii LPS-mediated activation of TLR4. Treatment of infected mice with the LpxC inhibitor enhanced clearance of the bacteria by enhancing opsonophagocytic killing, reduced serum LPS concentrations and inflammation, and completely protected the mice from lethal infection. These results identify a previously unappreciated potential for the new class of LpxC inhibitor antibiotics to treat XDR A. baumannii infections. Furthermore, they have far-reaching implications for pathogenesis and treatment of infections caused by GNB and for the discovery of novel antibiotics not detected by standard in vitro screens. Novel treatments are needed for infections caused by Acinetobacter baumannii, a Gram-negative bacterium that is extremely antibiotic resistant. The current study was undertaken to understand the immunopathogenesis of these infections, as a basis for defining novel treatments. The primary strain characteristic that differentiated virulent from less-virulent strains was shedding of Gram-negative lipopolysaccharide (LPS) during growth. A novel class of antibiotics, called LpxC inhibitors, block LPS synthesis, but these drugs do not demonstrate the ability to kill A. baumannii in vitro. We found that an LpxC inhibitor blocked the ability of bacteria to activate the sepsis cascade, enhanced opsonophagocytic killing of the bacteria, and protected mice from lethal infection. Thus, an entire new class of antibiotics which is already in development has heretofore-unrecognized potential to treat A. baumannii infections. Furthermore, standard antibiotic screens based on in vitro killing failed to detect this treatment potential of LpxC inhibitors for A. baumannii infections.
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