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Bae JY, Yun I, Jun KI, Kim CJ, Lee M, Choi HJ. Association between Pneumonia Development and Virulence Gene Expression in Carbapenem-Resistant Acinetobacter baumannii Isolated from Clinical Specimens. THE CANADIAN JOURNAL OF INFECTIOUS DISEASES & MEDICAL MICROBIOLOGY = JOURNAL CANADIEN DES MALADIES INFECTIEUSES ET DE LA MICROBIOLOGIE MEDICALE 2023; 2023:8265683. [PMID: 38156310 PMCID: PMC10754638 DOI: 10.1155/2023/8265683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 11/15/2023] [Accepted: 12/13/2023] [Indexed: 12/30/2023]
Abstract
We investigated the virulence gene expression of carbapenem-resistant Acinetobacter baumanii (CRAB) isolated from the respiratory samples of patients with CRAB pneumonia and those with CRAB colonization to identify the virulence genes contributing to CRAB pneumonia's development and mortality. Patients with CRAB identified from respiratory specimens were screened at a tertiary university hospital between January 2018 and January 2019. Patients were classified into CRAB pneumonia or CRAB colonization groups according to predefined clinical criteria. A. baumannii isolated from respiratory specimens was examined for the expression levels of ompA, uspA, hfq, hisF, feoA, and bfnL by quantitative reverse-transcription polymerase chain reaction. Among 156 patients with CRAB from respiratory specimens, 17 and 24 met the criteria for inclusion in the pneumonia and colonization groups, respectively. The expression level of ompA was significantly higher in the pneumonia group than in the colonization group (1.45 vs. 0.63, P=0.03). The expression levels of ompA (1.97 vs. 0.86, P=0.02), hisF (1.06 vs. 0.10, P < 0.01), uspA (1.62 vs. 1.01, P < 0.01), and bfnL (3.14 vs. 2.14, P=0.03) were significantly higher in patients with 30-day mortality than in the surviving patients. Elevated expression of hisF (adjusted odds ratio = 5.93, P=0.03) and uspA (adjusted odds ratio = 7.36, P=0.02) were associated with 30-day mortality after adjusting for age and the Charlson score. uspA and hisF may serve as putative targets for novel therapeutic strategies.
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Affiliation(s)
- Ji Yun Bae
- Department of Internal Medicine, Ewha Womans University Mokdong Hospital, Seoul, Republic of Korea
- Ewha Education and Research Center for Infection, Seoul, Republic of Korea
- Department of Internal Medicine, Ewha Womans University Seoul Hospital, Seoul, Republic of Korea
| | - Ina Yun
- Ewha Education and Research Center for Infection, Seoul, Republic of Korea
| | - Kang Il Jun
- Ewha Education and Research Center for Infection, Seoul, Republic of Korea
- Department of Internal Medicine, Ewha Womans University Seoul Hospital, Seoul, Republic of Korea
| | - Chung-Jong Kim
- Ewha Education and Research Center for Infection, Seoul, Republic of Korea
- Department of Internal Medicine, Ewha Womans University Seoul Hospital, Seoul, Republic of Korea
| | - Miae Lee
- Ewha Education and Research Center for Infection, Seoul, Republic of Korea
- Department of Laboratory Medicine, Ewha Womans University Mokdong Hospital, Seoul, Republic of Korea
- Department of Laboratory Medicine, Seegene Medical Foundation, Seoul, Republic of Korea
| | - Hee Jung Choi
- Department of Internal Medicine, Ewha Womans University Mokdong Hospital, Seoul, Republic of Korea
- Ewha Education and Research Center for Infection, Seoul, Republic of Korea
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Zhang MN, Zhao XO, Cui Q, Zhu DM, Wisal MA, Yu HD, Kong LC, Ma HX. Famotidine Enhances Rifampicin Activity against Acinetobacter baumannii by Affecting OmpA. J Bacteriol 2023; 205:e0018723. [PMID: 37439688 PMCID: PMC10448789 DOI: 10.1128/jb.00187-23] [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: 06/15/2023] [Accepted: 06/26/2023] [Indexed: 07/14/2023] Open
Abstract
The development of novel antibiotic adjuvants is imminent because of the frequent emergence of resistance in Gram-negative bacteria, which severely restricts the efficiency and longevity of commonly used clinical antibiotics. It is reported that famotidine, a clinical inhibitor of gastric acid secretion, enhances the antibacterial activity of rifamycin antibiotics, especially rifampicin, against Gram-negative bacteria and reverses drug resistance. Studies have shown that famotidine disrupts the cell membrane of Acinetobacter baumannii and inhibits the expression of the outer membrane protein ompA gene, while causing a dissipation of the plasma membrane potential, compensatively upregulating the pH gradient and ultimately increasing the accumulation of reactive oxygen species by leading to increased bacterial mortality. In addition, famotidine also inhibited the efflux pump activity and the biofilm formation of A. baumannii. In the Galleria mellonella and mouse infection models, the combination of famotidine and rifampicin increased the survival rate of infected animals and decreased the bacterial load in mouse organs. In conclusion, famotidine has the potential to be a novel rifampicin adjuvant, providing a new option for the treatment of clinical Gram-negative bacterial infections. IMPORTANCE In this study, famotidine was discovered for the first time to have potential as an antibiotic adjuvant, enhancing the antibacterial activity of rifamycin antibiotics against A. baumannii and overcoming the limitations of drug therapy. With the discovery of novel applications for the guanidine-containing medication famotidine, the viability of screening prospective antibiotic adjuvants from guanidine-based molecules was further explored. In addition, famotidine exerts activity by affecting the OmpA protein of the cell membrane, indicating that this protein might be used as a therapeutic drug target to treat A. baumannii infections.
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Affiliation(s)
- Meng-na Zhang
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, China
| | - Xiao-ou Zhao
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, China
- Branch of Animal Husbandry, Jilin Academy of Agricultural Science, Changchun, China
| | - Qi Cui
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, China
| | - Dao-mi Zhu
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, China
| | - Muhammad Asif Wisal
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, China
| | - Han-dong Yu
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, China
| | - Ling-cong Kong
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, China
| | - Hong-xia Ma
- College of Animal Science and Technology, Jilin Agricultural University, Changchun, China
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Memariani H, Memariani M. Antibiofilm properties of cathelicidin LL-37: an in-depth review. World J Microbiol Biotechnol 2023; 39:99. [PMID: 36781570 DOI: 10.1007/s11274-023-03545-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 02/08/2023] [Indexed: 02/15/2023]
Abstract
Notwithstanding ceaseless endeavors toward developing effective antibiofilm chemotherapeutics, biofilm-associated infections continue to be one of the most perplexing challenges confronting medicine today. Endogenous host defense peptides, such as the human cathelicidin LL-37, are being propounded as promising options for treating such infectious diseases. Over the past decennium, LL-37 has duly received tremendous research attention by virtue of its broad-spectrum antimicrobial activity and immunomodulatory properties. No attempt has hitherto been made, as far as we are aware, to comprehensively review the antibiofilm effects of LL-37. Accordingly, the intent in this paper is to provide a fairly all-embracing review of the literature available on the subject. Accumulating evidence suggests that LL-37 is able to prevent biofilm establishment by different bacterial pathogens such as Acinetobacter baumannii, Aggregatibacter actinomycetemcomitans, Bacteroides fragilis, Burkholderia thailandensis, Cutibacterium acnes, Escherichia coli, Francisella tularensis, Helicobacter pylori, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, and Streptococcus pyogenes. Inhibition of bacterial adhesion, downregulation of biofilm-associated genes, suppression of quorum-sensing pathways, degradation of biofilm matrix, and eradication of biofilm-residing cells are the major mechanisms responsible for antibiofilm properties of LL-37. In terms of its efficacy and safety in vivo, there are still many questions to be answered. Undoubtedly, LL-37 can open up new windows of opportunity to prevent and treat obstinate biofilm-mediated infections.
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Affiliation(s)
- Hamed Memariani
- Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Mojtaba Memariani
- Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran.
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4
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Hubloher JJ, Van der Sande L, Schaudinn C, Müller V, Averhoff B. The Tol-Pal system of Acinetobacter baumannii is important for cell morphology, antibiotic resistance and virulence. Int Microbiol 2023:10.1007/s10123-022-00319-9. [PMID: 36648597 PMCID: PMC10397113 DOI: 10.1007/s10123-022-00319-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 12/27/2022] [Accepted: 12/30/2022] [Indexed: 01/18/2023]
Abstract
Acinetobacter baumannii is an opportunistic human pathogen that has become a global threat to healthcare institutions. This Gram-negative bacterium is one of the most successful human pathogens worldwide and responsible for hospital-acquired infections. This is due to its outstanding potential to adapt to very different environments, to persist in the human host and most important, its ability to develop multidrug resistance. Our combined approach of genomic and phenotypic analyses led to the identification of the envelope spanning Tol-Pal system in A. baumannii. We found that the deletion of the tolQ, tolR, tolA, tolB, and pal genes affects cell morphology and increases antibiotic sensitivity, such as the ∆tol-pal mutant exhibits a significantly increased gentamicin and bacitracin sensitivity. Furthermore, Galleria mellonella caterpillar killing assays revealed that the ∆tol-pal mutant exhibits a decreased killing phenotype. Taken together, our findings suggest that the Tol-Pal system is important for cell morphology, antibiotic resistance, and virulence of A. baumannii.
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Affiliation(s)
- Josephine Joy Hubloher
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Goethe-University Frankfurt Am Main, Max-Von-Laue-Str. 9, 60438, Frankfurt, Germany
| | - Lisa Van der Sande
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Goethe-University Frankfurt Am Main, Max-Von-Laue-Str. 9, 60438, Frankfurt, Germany
| | - Christoph Schaudinn
- Advanced Light and Electron Microscopy ZBS4, Robert-Koch-Institut, Berlin, Germany
| | - Volker Müller
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Goethe-University Frankfurt Am Main, Max-Von-Laue-Str. 9, 60438, Frankfurt, Germany
| | - Beate Averhoff
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Goethe-University Frankfurt Am Main, Max-Von-Laue-Str. 9, 60438, Frankfurt, Germany.
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Garrido C, Wollman FA, Lafontaine I. The evolutionary history of peptidases involved in the processing of Organelle-Targeting Peptides. Genome Biol Evol 2022; 14:6618273. [PMID: 35758251 PMCID: PMC9291397 DOI: 10.1093/gbe/evac101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/23/2022] [Indexed: 11/25/2022] Open
Abstract
Most of the proteins present in mitochondria and chloroplasts, the organelles acquired via endosymbiotic events, are encoded in the nucleus and translated into the cytosol. Most of such nuclear-encoded proteins are specifically recognized via an N-terminal-encoded targeting peptide (TP) and imported into the organelles via a translocon machinery. Once imported, the TP is degraded by a succession of cleavage steps ensured by dedicated peptidases. Here, we retrace the evolution of the families of the mitochondrial processing peptidase (MPP), stromal processing peptidase (SPP), presequence protease (PreP), and organellar oligo-peptidase (OOP) that play a central role in TP processing and degradation across the tree of life. Their bacterial distributions are widespread but patchy, revealing unsurprisingly complex history of lateral transfers among bacteria. We provide evidence for the eukaryotic acquisition of MPP, OOP, and PreP by lateral gene transfers from bacteria at the time of the mitochondrial endosymbiosis. We show that the acquisition of SPP and of a second copy of OOP and PreP at the time of the chloroplast endosymbiosis was followed by a differential loss of one PreP paralog in photosynthetic eukaryotes. We identified some contrasting sequence conservations between bacterial and eukaryotic homologs that could reflect differences in the functional context of their peptidase activity. The close vicinity of the eukaryotic peptidases MPP and OOP to those of several bacterial pathogens, showing antimicrobial resistance, supports a scenario where such bacteria were instrumental in the establishment of the proteolytic pathway for TP degradation in organelles. The evidence for their role in the acquisition of PreP is weaker, and none is observed for SPP, although it cannot be excluded by the present study.
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Affiliation(s)
- Clotilde Garrido
- UMR7141, Institut de Biologie Physico-Chimique (CNRS/Sorbonne Université), 13 Rue Pierre et Marie Curie, 75005 Paris, France
| | - Francis André Wollman
- UMR7141, Institut de Biologie Physico-Chimique (CNRS/Sorbonne Université), 13 Rue Pierre et Marie Curie, 75005 Paris, France
| | - Ingrid Lafontaine
- UMR7141, Institut de Biologie Physico-Chimique (CNRS/Sorbonne Université), 13 Rue Pierre et Marie Curie, 75005 Paris, France
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6
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Xiao Q, Luo Y, Shi W, Lu Y, Xiong R, Wu X, Huang H, Zhao C, Zeng J, Chen C. The effects of LL-37 on virulence factors related to the quorum sensing system of Pseudomonas aeruginosa. ANNALS OF TRANSLATIONAL MEDICINE 2022; 10:284. [PMID: 35434009 PMCID: PMC9011280 DOI: 10.21037/atm-22-617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 03/04/2022] [Indexed: 11/24/2022]
Abstract
Background Antimicrobial peptides (AMPs) have shown promise in the treatment of multi-resistant pathogens. It was therefore of interest to analyze the effects of the AMP LL-37 on the regulation of several virulence factors related to the quorum sensing (QS) system of Pseudomonas aeruginosa (P. aeruginosa) in vitro. Methods The minimum inhibitory concentration (MIC) was evaluated by the micro broth dilution method. The expression of QS-related and QS-regulated virulence factor genes was also evaluated. Exotoxin A activity was measured with the nicotinamide adenine dinucleotide (NAD) (Coenzyme I) method; Elastase activity was detected with the elastin-Congo red (ECR) method; Pyocyanin detection was performed using the chloroform extraction method. The effects of LL-37 were assessed by measuring the expression changes of the virulence protein-encoding genes of the strains with quantitative polymerase chain reaction (PCR). Results The MIC of LL-37 against both P. aeruginosa reference strain (ATCC 15692 PAO1) and PA-ΔlasI/rhII was therefore determined to be 256 µg/mL. LL-37 at sub-minimum inhibitory concentrations (sub-MICs) had no significant effects on P. aeruginosa bacterial growth (P>0.05), but significantly downregulated the expression of all 3 virulence factors. Conclusions Interestingly, this effect appeared to be dose-related. These findings suggest that LL-37 could be a potential candidate for QS inhibition against bacterial infection and may have significant clinical potential in the treatment of P. aeruginosa biofilms.
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Affiliation(s)
- Qian Xiao
- Department of Laboratory Medicine, Guangdong Hospital of Traditional Chinese Medicine, Guangzhou, China.,The Second Clinical College of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Yanfen Luo
- Department of Laboratory Medicine, Guangdong Hospital of Traditional Chinese Medicine, Guangzhou, China.,The Second Clinical College of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Wen Shi
- Department of Laboratory Medicine, Guangdong Hospital of Traditional Chinese Medicine, Guangzhou, China.,The Second Clinical College of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Yang Lu
- Department of Laboratory Medicine, Guangdong Hospital of Traditional Chinese Medicine, Guangzhou, China.,The Second Clinical College of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Rui Xiong
- Department of Laboratory Medicine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Xinggui Wu
- Department of Laboratory Medicine, Guangdong Hospital of Traditional Chinese Medicine, Guangzhou, China.,The Second Clinical College of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Haihao Huang
- Department of Laboratory Medicine, Guangdong Hospital of Traditional Chinese Medicine, Guangzhou, China.,The Second Clinical College of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Chanjing Zhao
- Department of Laboratory Medicine, Guangdong Hospital of Traditional Chinese Medicine, Guangzhou, China.,The Second Clinical College of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Jianming Zeng
- Department of Laboratory Medicine, Guangdong Hospital of Traditional Chinese Medicine, Guangzhou, China.,The Second Clinical College of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Cha Chen
- Department of Laboratory Medicine, Guangdong Hospital of Traditional Chinese Medicine, Guangzhou, China.,The Second Clinical College of Guangzhou University of Chinese Medicine, Guangzhou, China
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7
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Magda M, Bettoni S, Laabei M, Fairley D, Russo TA, Riesbeck K, Blom AM. Clinical Isolates of Acinetobacter spp. Are Highly Serum Resistant Despite Efficient Recognition by the Complement System. Front Immunol 2022; 13:814193. [PMID: 35173727 PMCID: PMC8841485 DOI: 10.3389/fimmu.2022.814193] [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: 11/12/2021] [Accepted: 01/13/2022] [Indexed: 11/13/2022] Open
Abstract
Gram-negative bacteria from the genus Acinetobacter are responsible for life-threating hospital-related infections such as pneumonia, septicemia, and meningitis, especially in immunocompromised patients. Worryingly, Acinetobacter have become multi- and extensively drug resistant (MDR/XDR) over the last few decades. The complement system is the first line of defense against microbes, thus it is highly important to increase our understanding of evasion mechanisms used by Acinetobacter spp. Here, we studied clinical isolates of Acinetobacter spp. (n=50), aiming to characterize their recognition by the complement system. Most isolates tested survived 1 h incubation in 30% serum, and only 8 isolates had a lower survival rate, yet none of those isolates were fully killed. Intriguingly, four isolates survived in human whole blood containing all cell component. Their survival was, however, significantly reduced. Flow cytometry analyses revealed that most of the isolates were detected by human IgG and IgM. Interestingly, we could not detect any significant concentration of deposited C1q, despite observing C4b deposition that was abolished in C1q-deficient serum, indicating transient binding of C1q to bacteria. Moreover, several isolates were recognized by MBL, with C4b deposition abolished in MBL-deficient serum. C3b was deposited on most isolates, but this was not, however, seen with respect to C5b and formation of the membrane attack complex (MAC), indicating that many isolates could avoid complement-mediated lysis. India ink staining showed that isolates were capsulated, and capsule thickness varied significantly between isolates. Studies performed on a wild-type strain and capsule mutant strains, demonstrated that the production of a capsular polysaccharide is one mechanism that mediates resistance to complement-mediated bactericidal activity by preventing MAC deposition and lysis. Our data showed that most clinical Acinetobacter spp. isolates are highly serum resistant despite being efficiently recognized by the complement system.
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Affiliation(s)
- Michal Magda
- Protein Chemistry, Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Serena Bettoni
- Protein Chemistry, Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Maisem Laabei
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Derek Fairley
- Department of Microbiology, Belfast Health and Social Care Trust, Belfast, United Kingdom
| | - Thomas A. Russo
- Veterans Administration Western New York Healthcare System, Department of Medicine, Jacobs School of Medicine and Biomedical Sciences, University Buffalo, Buffalo, NY, United States
| | - Kristian Riesbeck
- Clinical Microbiology, Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Anna M. Blom
- Protein Chemistry, Department of Translational Medicine, Lund University, Malmö, Sweden
- *Correspondence: Anna M. Blom,
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8
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Kaushik V, Tiwari M, Joshi R, Tiwari V. Therapeutic strategies against potential antibiofilm targets of multidrug-resistant Acinetobacter baumannii. J Cell Physiol 2022; 237:2045-2063. [PMID: 35083758 DOI: 10.1002/jcp.30683] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 11/30/2021] [Accepted: 01/07/2022] [Indexed: 12/12/2022]
Abstract
Acinetobacter baumannii is the causative agent of various hospital-acquired infections. Biofilm formation is one of the various antimicrobial resistance (AMR) strategies and is associated with high mortality and morbidity. Hence, it is essential to review the potential antibiofilm targets in A. baumannii and come up with different strategies to combat these potential targets. This review covers different pathways involved in the regulation of biofilm formation in A. baumannii like quorum sensing (QS), cyclic-di-GMP signaling, two-component system (TCS), outer-membrane protein (ompA), and biofilm-associated protein (BAP). A newly discovered mechanism of electrical signaling-mediated biofilm formation and contact-dependent biofilm modulation has also been discussed. As biofilm formation and its maintenance in A. baumannii is facilitated by these potential targets, the detailed study of these targets and pathways can bring light to different therapeutic strategies such as anti-biofilm peptides, natural and synthetic molecule inhibitors, QS molecule degrading enzymes, and other strategies. These strategies may help in suppressing the lethality of biofilm-mediated infections. Targeting essential proteins/targets which are crucial for biofilm formation and regulation may render new therapeutic strategies that can aid in combating biofilm, thus reducing the recalcitrant infections and morbidity associated with the biofilm of A. baumannii.
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Affiliation(s)
- Vaishali Kaushik
- Department of Biochemistry, Central University of Rajasthan, Ajmer, India
| | - Monalisa Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer, India
| | - Richa Joshi
- Department of Biochemistry, Central University of Rajasthan, Ajmer, India
| | - Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer, India
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Escobar‐Salom M, Torrens G, Jordana‐Lluch E, Oliver A, Juan C. Mammals' humoral immune proteins and peptides targeting the bacterial envelope: from natural protection to therapeutic applications against multidrug‐resistant
Gram
‐negatives. Biol Rev Camb Philos Soc 2022; 97:1005-1037. [PMID: 35043558 PMCID: PMC9304279 DOI: 10.1111/brv.12830] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 12/12/2021] [Accepted: 12/15/2021] [Indexed: 12/11/2022]
Abstract
Mammalian innate immunity employs several humoral ‘weapons’ that target the bacterial envelope. The threats posed by the multidrug‐resistant ‘ESKAPE’ Gram‐negative pathogens (Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) are forcing researchers to explore new therapeutic options, including the use of these immune elements. Here we review bacterial envelope‐targeting (peptidoglycan and/or membrane‐targeting) proteins/peptides of the mammalian immune system that are most likely to have therapeutic applications. Firstly we discuss their general features and protective activity against ESKAPE Gram‐negatives in the host. We then gather, integrate, and discuss recent research on experimental therapeutics harnessing their bactericidal power, based on their exogenous administration and also on the discovery of bacterial and/or host targets that improve the performance of this endogenous immunity, as a novel therapeutic concept. We identify weak points and knowledge gaps in current research in this field and suggest areas for future work to obtain successful envelope‐targeting therapeutic options to tackle the challenge of antimicrobial resistance.
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Affiliation(s)
- María Escobar‐Salom
- Department of Microbiology University Hospital Son Espases‐Health Research Institute of the Balearic Islands (IdISBa) Carretera de Valldemossa 79 Palma Balearic Islands 07010 Spain
| | - Gabriel Torrens
- Department of Microbiology University Hospital Son Espases‐Health Research Institute of the Balearic Islands (IdISBa) Carretera de Valldemossa 79 Palma Balearic Islands 07010 Spain
| | - Elena Jordana‐Lluch
- Department of Microbiology University Hospital Son Espases‐Health Research Institute of the Balearic Islands (IdISBa) Carretera de Valldemossa 79 Palma Balearic Islands 07010 Spain
| | - Antonio Oliver
- Department of Microbiology University Hospital Son Espases‐Health Research Institute of the Balearic Islands (IdISBa) Carretera de Valldemossa 79 Palma Balearic Islands 07010 Spain
| | - Carlos Juan
- Department of Microbiology University Hospital Son Espases‐Health Research Institute of the Balearic Islands (IdISBa) Carretera de Valldemossa 79 Palma Balearic Islands 07010 Spain
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10
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Bharathi SV, Venkataramaiah M, Rajamohan G. Genotypic and Phenotypic Characterization of Novel Sequence Types of Carbapenem-Resistant Acinetobacter baumannii, With Heterogeneous Resistance Determinants and Targeted Variations in Efflux Operons. Front Microbiol 2022; 12:738371. [PMID: 35002996 PMCID: PMC8735875 DOI: 10.3389/fmicb.2021.738371] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 11/16/2021] [Indexed: 01/21/2023] Open
Abstract
Acinetobacter baumannii has emerged as one of the dominant nosocomial human pathogens associated with high morbidity and mortality globally. Increased incidences of carbapenem-resistant A. baumannii (CRAB) have resulted in an enormous socioeconomic burden on health-care systems. Here, we report the genotypic and phenotypic characterization of novel ST1816 and ST128 variants in A. baumannii strains belonging to International clone II (GC2) with capsule types KL1:OCL8 and KL3:OCL1d from India. Sequence analysis revealed the presence of diverse virulome and resistome in these clinical strains, in addition to islands, prophages, and resistance genes. The oxacillinase bla OXA-23 detected in the genomic island also highlighted the coexistence of bla OXA-66 /bla OXA-98 , bla ADC73 /bla ADC-3 , and bla TEM-1D in their mobile scaffolds, which is alarming. Together with these resistance-determining enzymes, multidrug efflux transporters also harbored substitutions, with increased expression in CRAB strains. The hotspot mutations in colistin resistance-conferring operons, PmrAB, LpxACD, and AdeRS, were additionally confirmed. Phenotype microarray analysis indicated that multidrug-resistant strains A. baumannii DR2 and A. baumannii AB067 preferred a range of antimicrobial compounds as their substrates relative to the other. To our knowledge, this is the first comprehensive report on the characterization of A. baumannii variants ST1816 and ST128, with different genetic makeup and genome organization. The occurrence of CRAB infections worldwide is a severe threat to available limited therapeutic options; hence, continued surveillance to monitor the emergence and dissemination of such novel ST variants in A. baumannii is imperative.
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Affiliation(s)
- Srinivasan Vijaya Bharathi
- Molecular Biology Division, Council of Scientific and Industrial Research-Institute of Microbial Technology, Chandigarh, India
| | - Manjunath Venkataramaiah
- Molecular Biology Division, Council of Scientific and Industrial Research-Institute of Microbial Technology, Chandigarh, India
| | - Govindan Rajamohan
- Molecular Biology Division, Council of Scientific and Industrial Research-Institute of Microbial Technology, Chandigarh, India
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11
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Pompilio A, Scribano D, Sarshar M, Di Bonaventura G, Palamara AT, Ambrosi C. Gram-Negative Bacteria Holding Together in a Biofilm: The Acinetobacter baumannii Way. Microorganisms 2021; 9:1353. [PMID: 34206680 PMCID: PMC8304980 DOI: 10.3390/microorganisms9071353] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/14/2021] [Accepted: 06/18/2021] [Indexed: 12/24/2022] Open
Abstract
Bacterial biofilms are a serious public-health problem worldwide. In recent years, the rates of antibiotic-resistant Gram-negative bacteria associated with biofilm-forming activity have increased worrisomely, particularly among healthcare-associated pathogens. Acinetobacter baumannii is a critically opportunistic pathogen, due to the high rates of antibiotic resistant strains causing healthcare-acquired infections (HAIs). The clinical isolates of A. baumannii can form biofilms on both biotic and abiotic surfaces; hospital settings and medical devices are the ideal environments for A. baumannii biofilms, thereby representing the main source of patient infections. However, the paucity of therapeutic options poses major concerns for human health infections caused by A. baumannii strains. The increasing number of multidrug-resistant A. baumannii biofilm-forming isolates in association with the limited number of biofilm-eradicating treatments intensify the need for effective antibiofilm approaches. This review discusses the mechanisms used by this opportunistic pathogen to form biofilms, describes their clinical impact, and summarizes the current and emerging treatment options available, both to prevent their formation and to disrupt preformed A. baumannii biofilms.
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Affiliation(s)
- Arianna Pompilio
- Center for Advanced Studies and Technology (CAST), Department of Medical, Oral and Biotechnological Sciences, Service of Clinical Microbiology, “G. d’Annunzio” University of Chieti-Pescara, 66100 Chieti, Italy; (A.P.); (G.D.B.)
| | - Daniela Scribano
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, Italy;
- Dani Di Giò Foundation-Onlus, 00193 Rome, Italy
| | - Meysam Sarshar
- Research Laboratories, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy;
| | - Giovanni Di Bonaventura
- Center for Advanced Studies and Technology (CAST), Department of Medical, Oral and Biotechnological Sciences, Service of Clinical Microbiology, “G. d’Annunzio” University of Chieti-Pescara, 66100 Chieti, Italy; (A.P.); (G.D.B.)
| | - Anna Teresa Palamara
- Department of Infectious Diseases, Istituto Superiore di Sanità, 00161 Rome, Italy;
- Laboratory Affiliated to Institute Pasteur Italia-Cenci Bolognetti Foundation, Department of Public Health and Infectious Diseases, Sapienza University of Rome, 00185 Rome, Italy
| | - Cecilia Ambrosi
- Department of Human Sciences and Promotion of the Quality of Life, San Raffaele Open University, IRCCS, 00166 Rome, Italy
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12
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Roy R, You RI, Chang CH, Yang CY, Lin NT. Carboxy-Terminal Processing Protease Controls Production of Outer Membrane Vesicles and Biofilm in Acinetobacter baumannii. Microorganisms 2021; 9:microorganisms9061336. [PMID: 34203028 PMCID: PMC8234194 DOI: 10.3390/microorganisms9061336] [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: 04/30/2021] [Revised: 06/14/2021] [Accepted: 06/17/2021] [Indexed: 12/12/2022] Open
Abstract
Carboxy-terminal processing protease (Ctp) is a serine protease that controls multiple cellular processes through posttranslational modification of proteins. Acinetobacter baumannii ATCC 17978 ctp mutant, namely MR14, is known to cause cell wall defects and autolysis. The objective of this study was to investigate the role of ctp mutation-driven autolysis in regulating biofilms in A. baumannii and to evaluate the vesiculation caused by cell wall defects. We found that in A. baumannii, Ctp is localized in the cytoplasmic membrane, and loss of Ctp function enhances the biofilm-forming ability of A. baumannii. Quantification of the matrix components revealed that extracellular DNA (eDNA) and proteins were the chief constituents of MR14 biofilm, and the transmission electron microscopy further indicated the presence of numerous dead cells compared with ATCC 17978. The large number of MR14 dead cells is potentially the result of compromised outer membrane integrity, as demonstrated by its high sensitivity to sodium dodecyl sulfate (SDS) and ethylenediaminetetraacetic acid (EDTA). MR14 also exhibited the hypervesiculation phenotype, producing outer-membrane vesicles (OMVs) of large mean size. The MR14 OMVs were more cytotoxic toward A549 cells than ATCC 17978 OMVs. Our overall results indicate that A. baumanniictp negatively controls pathogenic traits through autolysis and OMV biogenesis.
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Affiliation(s)
- Rakesh Roy
- Institute of Medical Sciences, Tzu Chi University, No. 701, Sec. 3, Zhongyang Rd., Hualien 97004, Taiwan;
| | - Ren-In You
- Department of Laboratory Medicine and Biotechnology, Tzu Chi University, No. 701, Sec. 3, Zhongyang Rd., Hualien 97004, Taiwan;
| | - Chan-Hua Chang
- Institute of Molecular Biology, National Chung Hsing University, Taichung 40227, Taiwan;
| | - Chiou-Ying Yang
- Institute of Molecular Biology, National Chung Hsing University, Taichung 40227, Taiwan;
- Correspondence: (C.-Y.Y.); (N.-T.L.); Tel.: +886-3-856 5301 (ext. 2080) (N.-T.L.); Fax: +886-3-8566724 (N.-T.L.)
| | - Nien-Tsung Lin
- Institute of Medical Sciences, Tzu Chi University, No. 701, Sec. 3, Zhongyang Rd., Hualien 97004, Taiwan;
- Department of Microbiology, School of Medicine, Tzu Chi University, No. 701, Sec. 3, Zhongyang Rd., Hualien 97004, Taiwan
- Correspondence: (C.-Y.Y.); (N.-T.L.); Tel.: +886-3-856 5301 (ext. 2080) (N.-T.L.); Fax: +886-3-8566724 (N.-T.L.)
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13
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Ridyard KE, Overhage J. The Potential of Human Peptide LL-37 as an Antimicrobial and Anti-Biofilm Agent. Antibiotics (Basel) 2021; 10:antibiotics10060650. [PMID: 34072318 PMCID: PMC8227053 DOI: 10.3390/antibiotics10060650] [Citation(s) in RCA: 79] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/20/2021] [Accepted: 05/25/2021] [Indexed: 02/06/2023] Open
Abstract
The rise in antimicrobial resistant bacteria threatens the current methods utilized to treat bacterial infections. The development of novel therapeutic agents is crucial in avoiding a post-antibiotic era and the associated deaths from antibiotic resistant pathogens. The human antimicrobial peptide LL-37 has been considered as a potential alternative to conventional antibiotics as it displays broad spectrum antibacterial and anti-biofilm activities as well as immunomodulatory functions. While LL-37 has shown promising results, it has yet to receive regulatory approval as a peptide antibiotic. Despite the strong antimicrobial properties, LL-37 has several limitations including high cost, lower activity in physiological environments, susceptibility to proteolytic degradation, and high toxicity to human cells. This review will discuss the challenges associated with making LL-37 into a viable antibiotic treatment option, with a focus on antimicrobial resistance and cross-resistance as well as adaptive responses to sub-inhibitory concentrations of the peptide. The possible methods to overcome these challenges, including immobilization techniques, LL-37 delivery systems, the development of LL-37 derivatives, and synergistic combinations will also be considered. Herein, we describe how combination therapy and structural modifications to the sequence, helicity, hydrophobicity, charge, and configuration of LL-37 could optimize the antimicrobial and anti-biofilm activities of LL-37 for future clinical use.
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14
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Yang X, Niu L, Pan Y, Feng X, Liu J, Guo Y, Pan C, Geng F, Tang X. LL-37-Induced Autophagy Contributed to the Elimination of Live Porphyromonas gingivalis Internalized in Keratinocytes. Front Cell Infect Microbiol 2020; 10:561761. [PMID: 33178622 PMCID: PMC7593823 DOI: 10.3389/fcimb.2020.561761] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 09/21/2020] [Indexed: 12/11/2022] Open
Abstract
Porphyromonas gingivalis (P. gingivalis), one of the most important pathogens of periodontitis, is closely associated with the aggravation and recurrence of periodontitis and systemic diseases. Antibacterial peptide LL-37, transcribed from the cathelicidin antimicrobial peptide (CAMP) gene, exhibits a broad spectrum of antibacterial activity and regulates the immune system. In this study, we demonstrated that LL-37 reduced the number of live P. gingivalis (ATCC 33277) in HaCaT cells in a dose-dependent manner via an antibiotic-protection assay. LL-37 promoted autophagy of HaCaT cells internalized with P. gingivalis. Inhibition of autophagy with 3-methyladenine (3-MA) weakened the inhibitory effect of LL-37 on the number of intracellular P. gingivalis. A cluster of orthologous groups (COGs) and a gene ontology (GO) functional analysis were used to individually assign 65 (10%) differentially expressed genes (DEGs) to an "Intracellular trafficking, secretion, and vesicular transport" cluster and 306 (47.08%) DEGs to metabolic processes including autophagy. Autophagy-related genes, a tripartite motif-containing 22 (TRIM22), and lysosomal-associated membrane protein 3 (LAMP3) were identified as potentially involved in LL-37-induced autophagy. Finally, bioinformatics software was utilized to construct and predict the protein-protein interaction (PPI) network of CAMP-TRIM22/LAMP3-Autophagy. The findings indicated that LL-37 can reduce the quantity of live P. gingivalis internalized in HaCaT cells by promoting autophagy in these cells. The transcriptome sequencing and analysis also revealed the potential molecular pathway of LL-37-induced autophagy.
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Affiliation(s)
- Xue Yang
- Department of Periodontology, School and Hospital of Stomatology, China Medical University, Shenyang, China.,Liaoning Provincial Key Laboratory of Oral Diseases, School of Stomatology, China Medical University, Shenyang, China
| | - Li Niu
- Department of Periodontology, School and Hospital of Stomatology, China Medical University, Shenyang, China.,Liaoning Provincial Key Laboratory of Oral Diseases, School of Stomatology, China Medical University, Shenyang, China
| | - Yaping Pan
- Department of Periodontology, School and Hospital of Stomatology, China Medical University, Shenyang, China.,Liaoning Provincial Key Laboratory of Oral Diseases, School of Stomatology, China Medical University, Shenyang, China
| | - Xianghui Feng
- Department of Periodontology, Peking University School and Hospital of Stomatology, Beijing, China
| | - Jie Liu
- Center of Science Experiment, China Medical University, Shenyang, China
| | - Yan Guo
- Liaoning Provincial Key Laboratory of Oral Diseases, School of Stomatology, China Medical University, Shenyang, China.,Department of Oral Biology, School of Stomatology, China Medical University, Shenyang, China
| | - Chunling Pan
- Department of Periodontology, School and Hospital of Stomatology, China Medical University, Shenyang, China.,Liaoning Provincial Key Laboratory of Oral Diseases, School of Stomatology, China Medical University, Shenyang, China
| | - Fengxue Geng
- Department of Periodontology, School and Hospital of Stomatology, China Medical University, Shenyang, China.,Liaoning Provincial Key Laboratory of Oral Diseases, School of Stomatology, China Medical University, Shenyang, China
| | - Xiaolin Tang
- Department of Periodontology, School and Hospital of Stomatology, China Medical University, Shenyang, China.,Liaoning Provincial Key Laboratory of Oral Diseases, School of Stomatology, China Medical University, Shenyang, China
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15
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Uppalapati SR, Sett A, Pathania R. The Outer Membrane Proteins OmpA, CarO, and OprD of Acinetobacter baumannii Confer a Two-Pronged Defense in Facilitating Its Success as a Potent Human Pathogen. Front Microbiol 2020; 11:589234. [PMID: 33123117 PMCID: PMC7573547 DOI: 10.3389/fmicb.2020.589234] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 09/11/2020] [Indexed: 12/12/2022] Open
Abstract
Of all the ESKAPE pathogens, carbapenem-resistant and multidrug-resistant Acinetobacter baumannii is the leading cause of hospital-acquired and ventilator-associated pneumonia. A. baumannii infections are notoriously hard to eradicate due to its propensity to rapidly acquire multitude of resistance determinants and the virulence factor cornucopia elucidated by the bacterium that help it fend off a wide range of adverse conditions imposed upon by host and environment. One such weapon in the arsenal of A. baumannii is the outer membrane protein (OMP) compendium. OMPs in A. baumannii play distinctive roles in facilitating the bacterial acclimatization to antibiotic- and host-induced stresses, albeit following entirely different mechanisms. OMPs are major immunogenic proteins in bacteria conferring bacteria host-fitness advantages including immune evasion, stress tolerance, and resistance to antibiotics and antibacterials. In this review, we summarize the current knowledge of major A. baumannii OMPs and discuss their versatile role in antibiotic resistance and virulence. Specifically, we explore how OmpA, CarO, and OprD-like porins mediate antibiotic and amino acid shuttle and host virulence.
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Affiliation(s)
- Siva R Uppalapati
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, India
| | - Abhiroop Sett
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, India
| | - Ranjana Pathania
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, India
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16
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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: 38] [Impact Index Per Article: 9.5] [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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17
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Abstract
Acinetobacter baumannii is nowadays a relevant nosocomial pathogen characterized by multidrug resistance (MDR) and concomitant difficulties to treat infections. OmpA is the most abundant A. baumannii outer membrane (OM) protein, and is involved in virulence, host-cell recognition, biofilm formation, regulation of OM stability, permeability and antibiotic resistance. OmpA members are two-domain proteins with an N-terminal eight-stranded β-barrel domain with four external loops (ELs) interacting with the environment, and a C-terminal periplasmic domain binding non-covalently to the peptidoglycan. Here, we combined data from genome sequencing, phylogenetic and multilocus sequence analyses from 975 strains/isolates of the Acinetobacter calcoaceticus/Acinetobacter baumannii complex (ACB), 946 from A. baumannii, to explore ompA microevolutionary divergence. Five major ompA variant groups were identified (V1 to V5) in A. baumannii, encompassing 52 different alleles coding for 23 different proteins. Polymorphisms were concentrated in five regions corresponding to the four ELs and the C-terminal end, and provided evidence for intra-genic recombination. ompA variants were not randomly distributed across the A. baumannii phylogeny, with the most frequent V1(lct)a1 allele found in most clonal complex 2 (CC2) strains and the second most frequent V2(lct)a1 allele in the majority of CC1 strains. Evidence was found for assortative exchanges of ompA alleles not only between separate A. baumannii lineages, but also different ACB species. The overall results have implications for A. baumannii evolution, epidemiology, virulence and vaccine design.
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Affiliation(s)
- Alejandro M Viale
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET) and Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), 2000 Rosario, Argentina
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18
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Lin MF, Lin YY, Lan CY. Characterization of biofilm production in different strains of Acinetobacter baumannii and the effects of chemical compounds on biofilm formation. PeerJ 2020; 8:e9020. [PMID: 32523805 PMCID: PMC7261477 DOI: 10.7717/peerj.9020] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 03/28/2020] [Indexed: 12/23/2022] Open
Abstract
Acinetobacter baumannii, an important emerging pathogen of nosocomial infections, is known for its ability to form biofilms. Biofilm formation increases the survival rate of A. baumannii on dry surfaces and may contribute to its persistence in the hospital environment, which increases the probability of nosocomial infections and outbreaks. This study was undertaken to characterize the biofilm production of different strains of A. baumannii and the effects of chemical compounds, especially antibiotics, on biofilm formation. In this study, no statistically significant relationship was observed between the ability to form a biofilm and the antimicrobial susceptibility of the A. baumannii clinical isolates. Biofilm formation caused by A. baumannii ATCC 17978 after gene knockout of two-component regulatory system gene baeR, efflux pump genes emrA/emrB and outer membrane coding gene ompA revealed that all mutant strains had less biofilm formation than the wild-type strain, which was further supported by the images from scanning electron microscopy and confocal laser scanning microscopy. The addition of amikacin, colistin, LL-37 or tannic acid decreased the biofilm formation ability of A. baumannii. In contrast, the addition of lower subinhibitory concentration tigecycline increased the biofilm formation ability of A. baumannii. Minimum biofilm eradication concentrations of amikacin, imipenem, colistin, and tigecycline were increased obviously for both wild type and multidrug resistant clinical strain A. baumannii VGH2. In conclusion, the biofilm formation ability of A. baumannii varied in different strains, involved many genes and could be influenced by many chemical compounds.
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Affiliation(s)
- Ming-Feng Lin
- Department of Medicine, National Taiwan University Hospital Chu-Tung Branch, Hsinchu County, Taiwan
| | - Yun-You Lin
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu, Taiwan
| | - Chung-Yu Lan
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu, Taiwan.,Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan
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19
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Outer membrane protein A (OmpA) as a potential therapeutic target for Acinetobacter baumannii infection. J Biomed Sci 2020; 27:26. [PMID: 31954394 PMCID: PMC6969976 DOI: 10.1186/s12929-020-0617-7] [Citation(s) in RCA: 125] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 01/14/2020] [Indexed: 01/12/2023] Open
Abstract
Acinetobacter baumannii (A. baumannii) is an important opportunistic pathogen causing serious nosocomial infections, which is considered as the most threatening Gram-negative bacteria (GNB). Outer membrane protein A (OmpA), a major component of outer membrane proteins (OMPs) in GNB, is a key virulence factor which mediates bacterial biofilm formation, eukaryotic cell infection, antibiotic resistance and immunomodulation. The characteristics of OmpA in Escherichia coli (E. coli) have been extensively studied since 1974, but only in recent years researchers started to clarify the functions of OmpA in A. baumannii. In this review, we summarized the structure and functions of OmpA in A. baumannii (AbOmpA), collected novel therapeutic strategies against it for treating A. baumannii infection, and emphasized the feasibility of using AbOmpA as a potential therapeutic target.
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20
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Jaśkiewicz M, Neubauer D, Kazor K, Bartoszewska S, Kamysz W. Antimicrobial Activity of Selected Antimicrobial Peptides Against Planktonic Culture and Biofilm of Acinetobacter baumannii. Probiotics Antimicrob Proteins 2019; 11:317-324. [PMID: 30043322 PMCID: PMC6449538 DOI: 10.1007/s12602-018-9444-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Acinetobacter baumannii is one of the most challenging pathogens, on account of its predisposition to develop resistance leading to severe, difficult-to-treat infections. As these bacteria are more usually isolated from nosocomial infections, the new therapeutic options are demanded. Antimicrobial peptides (AMPs) are compounds likely to find application in the treatment of A. baumannii. These compounds exhibit a wide spectrum of antimicrobial activity and were found to be effective against biofilm. In this study, eight AMPs, namely aurein 1.2, CAMEL, citropin 1.1., LL-37, omiganan, r-omiganan, pexiganan, and temporin A, were tested for their antimicrobial activity. A reference strain of A. baumannii ATCC 19606 was used. Antimicrobial assays included determination of the minimum inhibitory concentration and the minimum biofilm eradication concentration. Considering the fact that the majority of A. baumannii infections are associated with mechanical ventilation and the use of indwelling devices, the activity against biofilm was assessed on both a polystyrene surface and tracheal tube fragments. In addition, cytotoxicity (HaCaT) was determined and in vitro selectivity index was calculated.
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Affiliation(s)
- Maciej Jaśkiewicz
- Department of Inorganic Chemistry, Faculty of Pharmacy, Medical University of Gdansk, Gdansk, Poland.
| | - Damian Neubauer
- Department of Inorganic Chemistry, Faculty of Pharmacy, Medical University of Gdansk, Gdansk, Poland
| | - Kamil Kazor
- Department of Inorganic Chemistry, Faculty of Pharmacy, Medical University of Gdansk, Gdansk, Poland
| | - Sylwia Bartoszewska
- Department of Inorganic Chemistry, Faculty of Pharmacy, Medical University of Gdansk, Gdansk, Poland
| | - Wojciech Kamysz
- Department of Inorganic Chemistry, Faculty of Pharmacy, Medical University of Gdansk, Gdansk, Poland
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21
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Li FJ, Starrs L, Burgio G. Tug of war between Acinetobacter baumannii and host immune responses. Pathog Dis 2019; 76:5290314. [PMID: 30657912 DOI: 10.1093/femspd/ftz004] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 01/16/2019] [Indexed: 02/06/2023] Open
Abstract
Acinetobacter baumannii is an emerging nosocomial, opportunistic pathogen with growing clinical significance. Acinetobacter baumannii has an exceptional ability to rapidly develop drug resistance and to adhere to abiotic surfaces, including medical equipment, significantly promoting bacterial spread and also limiting our ability to control A. baumannii infections. Consequently, A. baumannii is frequently responsible for ventilator-associated pneumonia in clinical settings. In order to develop an effective treatment strategy, understanding host-pathogen interactions during A. baumannii infection is crucial. Various A. baumannii virulence factors have been identified as targets of host innate pattern-recognition receptors, which leads to activation of downstream inflammasomes to develop inflammatory responses, and the recruitment of innate immune effectors against A. baumannii infection. To counteract host immune attack, A. baumannii regulates its expression of different virulence factors. This review summarizes the significance of mechanisms of host-bacteria interaction, as well as different bacteria and host defense mechanisms during A. baumannii infection.
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Affiliation(s)
- Fei-Ju Li
- Department of Immunology and infectious Diseases, John Curtin School of Medical Research, Australian National University, 131 Garran Road, Acton, ACT 2601, Australia
| | - Lora Starrs
- Department of Immunology and infectious Diseases, John Curtin School of Medical Research, Australian National University, 131 Garran Road, Acton, ACT 2601, Australia
| | - Gaetan Burgio
- Department of Immunology and infectious Diseases, John Curtin School of Medical Research, Australian National University, 131 Garran Road, Acton, ACT 2601, Australia
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22
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Saul-McBeth J, Matson JS. A Periplasmic Antimicrobial Peptide-Binding Protein Is Required for Stress Survival in Vibrio cholerae. Front Microbiol 2019; 10:161. [PMID: 30804918 PMCID: PMC6370654 DOI: 10.3389/fmicb.2019.00161] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 01/22/2019] [Indexed: 11/13/2022] Open
Abstract
Vibrio cholerae must sense and respond appropriately to stresses encountered in the aquatic environment and the human host. One stress encountered in both environments is exposure to antimicrobial peptides (AMPs), produced as a part of the innate immune response by all multicellular organisms. Previous transcriptomic analysis demonstrated that expression of Stress-inducible protein A (SipA) (VCA0732), a hypothetical protein, was highly induced by AMP exposure and was dependent on a specific uncharacterized two-component system. In order to better understand role of this protein in stress relief, we examined whether it shared any of the phenotypes reported for its homologs. SipA is required for survival in the presence of two other stressors, cadmium chloride and hydrogen peroxide, and it localizes to the bacterial periplasm, similar to its homologs. We also found that SipA physically interacts with OmpA. Importantly, we found that SipA binds AMPs in the bacterial periplasm. This suggests a model where SipA may act as a molecular chaperone, binding AMPs that enter the periplasm and delivering them to OmpA for removal from the cell. While El Tor V. cholerae strains lacking SipA do not show a survival defect in the presence of AMPs, we found that Classical sipA mutants are less able to survive in the presence of AMPs. This phenotype is likely masked in the El Tor background due to a functional lipid A modification system that increases AMP resistance in these strains. In summary, we have identified a protein that contributes to a novel mechanism of stress relief in V. cholerae.
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Affiliation(s)
- Jessica Saul-McBeth
- Department of Medical Microbiology and Immunology, University of Toledo, Toledo, OH, United States
| | - Jyl S Matson
- Department of Medical Microbiology and Immunology, University of Toledo, Toledo, OH, United States
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23
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Chen Z, Yang G, Lu S, Chen D, Fan S, Xu J, Wu B, He J. Design and antimicrobial activities of LL-37 derivatives inhibiting the formation of Streptococcus mutans
biofilm. Chem Biol Drug Des 2019; 93:1175-1185. [PMID: 30635992 DOI: 10.1111/cbdd.13419] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Revised: 10/03/2018] [Accepted: 10/07/2018] [Indexed: 12/12/2022]
Affiliation(s)
- Zhao Chen
- Department of Stomatology; Nanfang Hospital; Southern Medical University; Guangzhou China
- Group of Peptides and Natural Products Research; School of Pharmaceutical Sciences; Southern Medical University; Guangzhou China
| | - Guang Yang
- Group of Peptides and Natural Products Research; School of Pharmaceutical Sciences; Southern Medical University; Guangzhou China
| | - Shengsheng Lu
- Group of Peptides and Natural Products Research; School of Pharmaceutical Sciences; Southern Medical University; Guangzhou China
| | - Daiwei Chen
- Group of Peptides and Natural Products Research; School of Pharmaceutical Sciences; Southern Medical University; Guangzhou China
| | - Sheng Fan
- Group of Peptides and Natural Products Research; School of Pharmaceutical Sciences; Southern Medical University; Guangzhou China
| | - Junyang Xu
- Department of Stomatology; Nanfang Hospital; Southern Medical University; Guangzhou China
| | - Buling Wu
- Department of Stomatology; Nanfang Hospital; Southern Medical University; Guangzhou China
| | - Jian He
- Group of Peptides and Natural Products Research; School of Pharmaceutical Sciences; Southern Medical University; Guangzhou China
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Guo Y, Xun M, Han J. A bovine myeloid antimicrobial peptide (BMAP-28) and its analogs kill pan-drug-resistant Acinetobacter baumannii by interacting with outer membrane protein A (OmpA). Medicine (Baltimore) 2018; 97:e12832. [PMID: 30334982 PMCID: PMC6211872 DOI: 10.1097/md.0000000000012832] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Antimicrobial peptides (AMPs) exhibit multiple activities against bacteria and fungi. A bovine myeloid antimicrobial peptide (BMAP-28) belongs to the cathelicidin-derived AMPs and has antimicrobial activity. Due to the rapidly increasing number of infections and outbreaks caused by pan-drug-resistant Acinetobacter baumannii (PDRAB), we sought to determine whether BMAP-28 and its 4 analog peptides (A837, A838, A839, and A840) have antimicrobial activity against PDRAB. Furthermore, we clarified the possible mechanism of inhibition by which of BMAP-28 acts against PDRAB. In the current study, we examined the inhibitory effect of BMAP-28 and its 4 analog peptides on the growth of PDRAB through minimal inhibitory concentration (MIC) analysis and short time killing assays. We also evaluated the effects of BMAP-28 and its analogs on the bacterial cell surface through the use of field emission scanning electron microscopy (FE-SEM). In order to determine the inhibitory mechanism of BMAP-28, we examined the interaction between BMAP-28 and outer membrane proteins (OMPs), especially the interaction between BMAP-28 and A. baumannii OmpA (AbOmpA), which is the main component of OMPs, by using a quartz crystal microbalance (QCM). BMAP-28 and its 4 analogs were effective in inhibiting the growth of PDRAB and had rapid killing ability. BMAP-28 showed exceptionally strong and rapid inhibitory effects on PDRAB when compared to the other peptides and was also shown to cause damage to the cell surface of PDRAB. Moreover, QCM analysis provided evidence of potential interaction between BMAP-28 and AbOmpA. These data indicate that BMAP-28 is a promising candidate for the treatment of PDRAB infections and that its inhibitory effects were related with its binding to AbOmpA.
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Affiliation(s)
- Yijie Guo
- Key Laboratory of Environment and Genes Related to Diseases, Xi’an Jiaotong University, Ministry of Education of China
- Department of Pathogenic Biology and Immunology
| | - Meng Xun
- Key Laboratory of Environment and Genes Related to Diseases, Xi’an Jiaotong University, Ministry of Education of China
- Department of Pathogenic Biology and Immunology
| | - Jing Han
- Key Laboratory of Environment and Genes Related to Diseases, Xi’an Jiaotong University, Ministry of Education of China
- School of Public Health, Xi’an Jiaotong University, Health Science Center, Xi’an, China
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A Simplified Derivative of Human Defensin 5 with Potent and Efficient Activity against Multidrug-Resistant Acinetobacter baumannii. Antimicrob Agents Chemother 2018; 62:AAC.01504-17. [PMID: 29158275 DOI: 10.1128/aac.01504-17] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 11/04/2017] [Indexed: 02/08/2023] Open
Abstract
The increasing incidence of multidrug-resistant Acinetobacter baumannii (MDRAb) infections worldwide has necessitated the development of novel antibiotics. Human defensin 5 (HD5) is an endogenous peptide with a complex architecture and antibacterial activity against MDRAb In the present study, we attempted to simplify the structure of HD5 by removing disulfide bonds. We found that the Cys2-4 bond was most indispensable for HD5 to inactivate MDRAb, although the antibacterial activity of the derivative was significantly attenuated. We then replaced the noncationic and nonhydrophobic residues with electropositive Arg to increase the antibacterial activity of HD5 derivative that contains a Cys2-4 bond, obtaining another derivative termed HD5d5. The in vitro antibacterial assay and irradiation-wound-infection animal experiment both showed that HD5d5 was much more effective than HD5 at eliminating MDRAb Further investigations revealed that HD5d5 efficiently bound to outer membrane lipid A and penetrated membranes, leading to bacterial collapse and peptide translocation. Compared to HD5, more HD5d5 molecules were located in the cytoplasm of MDRAb, and HD5d5 was more efficient at reducing the activities of superoxide dismutase and catalase, causing the accumulation of reactive oxygen species that are detrimental to microbes. In addition, HD5 failed to suppress the pathogenic outer membrane protein A of Acinetobacter baumannii (AbOmpA) at concentrations up to 50 μg/ml, whereas HD5d5 strongly bound to AbOmpA and exhibited a dramatic toxin-neutralizing ability, thus expanding the repertoire of drugs that is available to treat MDRAb infections.
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26
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Lee JTY, Wang G, Tam YT, Tam C. Membrane-Active Epithelial Keratin 6A Fragments (KAMPs) Are Unique Human Antimicrobial Peptides with a Non-αβ Structure. Front Microbiol 2016; 7:1799. [PMID: 27891122 PMCID: PMC5105358 DOI: 10.3389/fmicb.2016.01799] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Accepted: 10/26/2016] [Indexed: 11/23/2022] Open
Abstract
Antibiotic resistance is a pressing global health problem that threatens millions of lives each year. Natural antimicrobial peptides and their synthetic derivatives, including peptoids and peptidomimetics, are promising candidates as novel antibiotics. Recently, the C-terminal glycine-rich fragments of human epithelial keratin 6A were found to have bactericidal and cytoprotective activities. Here, we used an improved 2-dimensional NMR method coupled with a new protocol for structural refinement by low temperature simulated annealing to characterize the solution structure of these kerain-derived antimicrobial peptides (KAMPs). Two specific KAMPs in complex with membrane mimicking sodium dodecyl sulfate (SDS) micelles displayed amphipathic conformations with only local bends and turns, and a central 10-residue glycine-rich hydrophobic strip that is central to bactericidal activity. To our knowledge, this is the first report of non-αβ structure for human antimicrobial peptides. Direct observation of Staphylococcus aureus and Pseudomonas aeruginosa by scanning and transmission electron microscopy showed that KAMPs deformed bacterial cell envelopes and induced pore formation. Notably, in competitive binding experiments, KAMPs demonstrated binding affinities to LPS and LTA that did not correlate with their bactericidal activities, suggesting peptide-LPS and peptide-LTA interactions are less important in their mechanisms of action. Moreover, immunoprecipitation of KAMPs-bacterial factor complexes indicated that membrane surface lipoprotein SlyB and intracellular machineries NQR sodium pump and ribosomes are potential molecular targets for the peptides. Results of this study improve our understanding of the bactericidal function of epithelial cytokeratin fragments, and highlight an unexplored class of human antimicrobial peptides, which may serve as non-αβ peptide scaffolds for the design of novel peptide-based antibiotics.
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Affiliation(s)
- Judy T Y Lee
- Department of Ophthalmic Research, Cole Eye Institute and Lerner Research Institute, Cleveland Clinic Cleveland, OH, USA
| | - Guangshun Wang
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center Omaha, NE, USA
| | - Yu Tong Tam
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison Madison, WI, USA
| | - Connie Tam
- Department of Ophthalmic Research, Cole Eye Institute and Lerner Research Institute, Cleveland ClinicCleveland, OH, USA; Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve UniversityCleveland, OH, USA
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27
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Characterization of surface antigen protein 1 (SurA1) from Acinetobacter baumannii and its role in virulence and fitness. Vet Microbiol 2016; 186:126-38. [PMID: 27016767 DOI: 10.1016/j.vetmic.2016.02.018] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2015] [Revised: 01/24/2016] [Accepted: 02/22/2016] [Indexed: 01/02/2023]
Abstract
Acinetobacter baumannii is a Gram-negative bacillus that causes nosocomial infections, such as bacteremia, pneumonia, and meningitis and urinary tract and wound infections. In the present study, the surface antigen protein 1 (SurA1) gene of A. baumannii strain CCGGD201101 was identified, cloned and expressed, and then its roles in fitness and virulence were investigated. Virulence was observed in the human lung cancer cell lines A549 and HEp-2 at one week after treatment with recombinant SurA1. One isogenic SurA1 knock-out strain, GR0015, which was derived from the A. baumannii strain CCGGD201101 isolated from diseased chicks in a previous study, highlighted the effect of SurA1 on fitness and growth. Its growth rate in LB broth and killing activity in human sera were significantly decreased compared with strain CCGGD201101. In the Galleria mellonella insect model, the isogenic SurA1 knock-out strain exhibited a lower survival rate and decreased dissemination. These results suggest that SurA1 plays an important role in the fitness and virulence of A. baumannii.
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