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Leonidou N, Xia Y, Friedrich L, Schütz MS, Dräger A. Exploring the metabolic profile of A. baumannii for antimicrobial development using genome-scale modeling. PLoS Pathog 2024; 20:e1012528. [PMID: 39312576 DOI: 10.1371/journal.ppat.1012528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Accepted: 08/26/2024] [Indexed: 09/25/2024] Open
Abstract
With the emergence of multidrug-resistant bacteria, the World Health Organization published a catalog of microorganisms urgently needing new antibiotics, with the carbapenem-resistant Acinetobacter baumannii designated as "critical". Such isolates, frequently detected in healthcare settings, pose a global pandemic threat. One way to facilitate a systemic view of bacterial metabolism and allow the development of new therapeutics is to apply constraint-based modeling. Here, we developed a versatile workflow to build high-quality and simulation-ready genome-scale metabolic models. We applied our workflow to create a metabolic model for A. baumannii and validated its predictive capabilities using experimental nutrient utilization and gene essentiality data. Our analysis showed that our model iACB23LX could recapitulate cellular metabolic phenotypes observed during in vitro experiments, while positive biomass production rates were observed and experimentally validated in various growth media. We further defined a minimal set of compounds that increase A. baumannii's cellular biomass and identified putative essential genes with no human counterparts, offering new candidates for future antimicrobial development. Finally, we assembled and curated the first collection of metabolic reconstructions for distinct A. baumannii strains and analyzed their growth characteristics. The presented models are in a standardized and well-curated format, enhancing their usability for multi-strain network reconstruction.
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Affiliation(s)
- Nantia Leonidou
- Computational Systems Biology of Infections and Antimicrobial-Resistant Pathogens, Institute for Bioinformatics and Medical Informatics (IBMI), Eberhard Karl University of Tübingen, Tübingen, Germany
- Department of Computer Science, Eberhard Karl University of Tübingen, Tübingen, Germany
- Cluster of Excellence 'Controlling Microbes to Fight Infections', Eberhard Karl University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), partner site Tübingen, Germany
- Quantitative Biology Center (QBiC), Eberhard Karl University of Tübingen, Tübingen, Germany
| | - Yufan Xia
- Department of Computer Science, Eberhard Karl University of Tübingen, Tübingen, Germany
| | - Lea Friedrich
- Interfaculty Institute for Microbiology and Infection Medicine, Institute for Medical Microbiology and Hygiene, University Hospital Tübingen, Tübingen, Germany
| | - Monika S Schütz
- Interfaculty Institute for Microbiology and Infection Medicine, Institute for Medical Microbiology and Hygiene, University Hospital Tübingen, Tübingen, Germany
| | - Andreas Dräger
- Computational Systems Biology of Infections and Antimicrobial-Resistant Pathogens, Institute for Bioinformatics and Medical Informatics (IBMI), Eberhard Karl University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), partner site Tübingen, Germany
- Quantitative Biology Center (QBiC), Eberhard Karl University of Tübingen, Tübingen, Germany
- Data Analytics and Bioinformatics, Institute of Computer Science, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
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2
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Cheewapat R, Redkimned J, Lekuthai S, Kitti T, Tasanapak K, Thanwisai A, Sitthisak S, Sornda T, Impheng H, Onsurathum S, Leungtongkam U, Lamlertthon S, Kucharoenphaibul S, Wongwigkarn J, Singkum P, Chanchaithong P, Thummeepak R. Genomic Landscape Reveals Chromosomally-Mediated Antimicrobial Resistome and Virulome of a High-Risk International Clone II Acinetobacter baumannii AB073 from Thailand. Glob Health Epidemiol Genom 2024; 2024:8872463. [PMID: 38716477 PMCID: PMC11074871 DOI: 10.1155/2024/8872463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 03/14/2024] [Accepted: 04/18/2024] [Indexed: 07/28/2024] Open
Abstract
This study utilized integrative bioinformatics' tools together with phenotypic assays to understand the whole-genome features of a carbapenem-resistant international clone II Acinetobacter baumannii AB073. Overall, we found the isolate to be resistant to seven antibiotic classes, penicillins, β-lactam/β-lactamase inhibitor combinations, cephalosporins, carbapenems, aminoglycosides, fluoroquinolones, and folate pathway antagonists. These resistance phenotypes are related to various chromosomal-located antibiotic resistance determinants involved in different mechanisms such as reduced permeability, antibiotic target protection, antibiotic target alteration, antibiotic inactivation, and antibiotic efflux. IC2 A. baumannii AB073 could not transfer antibiotic resistance by conjugation experiments. Likewise, mobilome analysis found that AB073 did not carry genetic determinants involving horizontal gene transfer. Moreover, this isolate also carried multiple genes associated with the ability of iron uptake, biofilm formation, immune invasion, virulence regulations, and serum resistance. In addition, the genomic epidemiological study showed that AB073-like strains were successful pathogens widespread in various geographic locations and clinical sources. In conclusion, the comprehensive analysis demonstrated that AB073 contained multiple genomic determinants which were important characteristics to classify this isolate as a successful international clone II obtained from Thailand.
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Affiliation(s)
- Rattiya Cheewapat
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand
| | - Jadsadaporn Redkimned
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand
| | - Sirikran Lekuthai
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand
| | - Thawatchai Kitti
- Department of Oriental Medicine, Chiang Rai College, Chiang Rai 57000, Thailand
| | - Kannipa Tasanapak
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand
| | - Aunchalee Thanwisai
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand
| | - Sutthirat Sitthisak
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand
| | - Thanet Sornda
- Department of Biochemistry, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand
| | - Hathaichanok Impheng
- Department of Physiology, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand
| | - Sudarat Onsurathum
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand
| | - Udomluk Leungtongkam
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand
| | - Supaporn Lamlertthon
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand
| | - Siriwat Kucharoenphaibul
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand
| | - Jintana Wongwigkarn
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand
| | - Pantira Singkum
- Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Salaya 10400, Thailand
| | - Pattrarat Chanchaithong
- Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Rapee Thummeepak
- Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand
- Centre of Excellence in Medical Biotechnology, Faculty of Medical Science, Naresuan University, Phitsanulok 65000, Thailand
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3
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Maure A, Robino E, Van der Henst C. The intracellular life of Acinetobacter baumannii. Trends Microbiol 2023; 31:1238-1250. [PMID: 37487768 DOI: 10.1016/j.tim.2023.06.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 06/16/2023] [Accepted: 06/23/2023] [Indexed: 07/26/2023]
Abstract
Acinetobacter baumannii is a Gram-negative opportunistic bacterium responsible for nosocomial and community-acquired infections. This pathogen is globally disseminated and associated with high levels of antibiotic resistance, which makes it an important threat to human health. Recently, new evidence showed that several A. baumannii isolates can survive and proliferate within eukaryotic professional and/or nonprofessional phagocytic cells, with in vivo consequences. This review provides updated information and describes the tools that A. baumannii possesses to adhere, colonize, and replicate in host cells. Additionally, we emphasize the high genetic and phenotypic heterogeneity detected amongst A. baumannii isolates and its impact on the bacterial intracellular features. We also discuss the need for standardized methods to characterize this pathogen robustly and consequently consider some strains as facultative intracellular bacteria.
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Affiliation(s)
- Alexandra Maure
- Microbial Resistance and Drug Discovery, VIB-VUB Center for Structural Biology, VIB, Flanders Institute for Biotechnology, Brussels, Belgium; Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Etienne Robino
- Microbial Resistance and Drug Discovery, VIB-VUB Center for Structural Biology, VIB, Flanders Institute for Biotechnology, Brussels, Belgium; Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Charles Van der Henst
- Microbial Resistance and Drug Discovery, VIB-VUB Center for Structural Biology, VIB, Flanders Institute for Biotechnology, Brussels, Belgium; Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium.
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Ma Y, Fei Y, Ding S, Jiang H, Fang J, Liu G. Trace metal elements: a bridge between host and intestinal microorganisms. SCIENCE CHINA. LIFE SCIENCES 2023; 66:1976-1993. [PMID: 37528296 DOI: 10.1007/s11427-022-2359-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 04/23/2023] [Indexed: 08/03/2023]
Abstract
Trace metal elements, such as iron, copper, manganese, and zinc, are essential nutrients for biological processes. Although their intake demand is low, they play a crucial role in cell homeostasis as the cofactors of various enzymes. Symbiotic intestinal microorganisms compete with their host for the use of trace metal elements. Moreover, the metabolic processes of trace metal elements in the host and microorganisms affect the organism's health. Supplementation or the lack of trace metal elements in the host can change the intestinal microbial community structure and function. Functional changes in symbiotic microorganisms can affect the host's metabolism of trace metal elements. In this review, we discuss the absorption and transport processes of trace metal elements in the host and symbiotic microorganisms and the effects of dynamic changes in the levels of trace metal elements on the intestinal microbial community structure. We also highlight the participation of trace metal elements as enzyme cofactors in the host immune process. Our findings indicate that the host uses metal nutrition immunity or metal poisoning to resist pathogens and improve immunity.
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Affiliation(s)
- Yong Ma
- College of Bioscience and Biotechnology, Hunan Agricultural University, Hunan Provincial Engineering Research Center of Applied Microbial Resources Development for Livestock and Poultry, Changsha, 410128, China
| | - Yanquan Fei
- College of Bioscience and Biotechnology, Hunan Agricultural University, Hunan Provincial Engineering Research Center of Applied Microbial Resources Development for Livestock and Poultry, Changsha, 410128, China
| | - Sujuan Ding
- College of Bioscience and Biotechnology, Hunan Agricultural University, Hunan Provincial Engineering Research Center of Applied Microbial Resources Development for Livestock and Poultry, Changsha, 410128, China
| | - Hongmei Jiang
- College of Bioscience and Biotechnology, Hunan Agricultural University, Hunan Provincial Engineering Research Center of Applied Microbial Resources Development for Livestock and Poultry, Changsha, 410128, China
| | - Jun Fang
- College of Bioscience and Biotechnology, Hunan Agricultural University, Hunan Provincial Engineering Research Center of Applied Microbial Resources Development for Livestock and Poultry, Changsha, 410128, China.
| | - Gang Liu
- College of Bioscience and Biotechnology, Hunan Agricultural University, Hunan Provincial Engineering Research Center of Applied Microbial Resources Development for Livestock and Poultry, Changsha, 410128, China
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5
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Ren X, Palmer LD. Acinetobacter Metabolism in Infection and Antimicrobial Resistance. Infect Immun 2023:e0043322. [PMID: 37191522 DOI: 10.1128/iai.00433-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023] Open
Abstract
Acinetobacter infections have high rates of mortality due to an increasing incidence of infections by multidrug-resistant (MDR) and extensively-drug-resistant (XDR) strains. Therefore, new therapeutic strategies for the treatment of Acinetobacter infections are urgently needed. Acinetobacter spp. are Gram-negative coccobacilli that are obligate aerobes and can utilize a wide variety of carbon sources. Acinetobacter baumannii is the main cause of Acinetobacter infections, and recent work has identified multiple strategies A. baumannii uses to acquire nutrients and replicate in the face of host nutrient restriction. Some host nutrient sources also serve antimicrobial and immunomodulatory functions. Hence, understanding Acinetobacter metabolism during infection may provide new insights into novel infection control measures. In this review, we focus on the role of metabolism during infection and in resistance to antibiotics and other antimicrobial agents and discuss the possibility that metabolism may be exploited to identify novel targets to treat Acinetobacter infections.
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Affiliation(s)
- Xiaomei Ren
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, Illinois, USA
| | - Lauren D Palmer
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, Illinois, USA
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Luo J, Chu X, Jie J, Sun Y, Guan Q, Li D, Luo ZQ, Song L. Acinetobacter baumannii Kills Fungi via a Type VI DNase Effector. mBio 2023; 14:e0342022. [PMID: 36625573 PMCID: PMC9973263 DOI: 10.1128/mbio.03420-22] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 12/13/2022] [Indexed: 01/11/2023] Open
Abstract
Many Gram-negative bacteria deploy a type VI secretion system (T6SS) to inject toxins into target cells to promote their survival and replication in complex environments. Here, we report that Acinetobacter baumannii uses its T6SS to kill fungi and that the effector TafE (ACX60_15365) is responsible for such killing. Although ectopically expressed TafE is toxic to both Escherichia coli and Saccharomyces cerevisiae, deletion of tafE only affects the antifungal activity of A. baumannii. We demonstrate that TafE is a DNase capable of targeting the nuclei of yeast cells and that an Ntox15 domain is essential for its ability to degrade DNA. Furthermore, our findings show that A. baumannii is protected from the toxicity of TafE by elaborating the immunity protein TaeI (ACX60_15360), which antagonizes the activity of the effector by direct binding. The discovery of A. baumannii T6SS effectors capable of killing multiple taxonomically distinct microbes has shed light on a mechanism of the high-level fitness of this pathogen in environments characterized by scarce nutrients and the potential presence of diverse microorganisms. IMPORTANCE Acinetobacter baumannii is an increasing important nosocomial pathogen that is difficult to combat due to its ability to survive in harsh environments and the emergence of isolates that are resistant to multiple antibiotics. A better understanding of the mechanism underlying the toughness of A. baumannii may identify its Achilles' heel, which will facilitate the development of novel preventive and treatment measures. In this study, our findings show that A. baumannii kills fungi with the DNase effector TafE injected into competitor cells by its type VI secretion system. A. baumannii is protected from the activity of TafE by the immunity protein TaeI, which inactivates the effector by direct binding. Our results suggest that inactivation of its T6SS or effectors may reduce the fitness of A. baumannii and increase the effectiveness of treatment by means such as antibiotics. Furthermore, our finding suggests that targeted degradation of TaeI may be an effective strategy to kill A. baumannii.
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Affiliation(s)
- Jingjing Luo
- Department of Respiratory Medicine, Center for Infectious Diseases and Pathogen Biology, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, State Key Laboratory for Zoonotic Diseases, The First Hospital of Jilin University, Changchun, China
| | - Xiao Chu
- Department of Respiratory Medicine, Center for Infectious Diseases and Pathogen Biology, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, State Key Laboratory for Zoonotic Diseases, The First Hospital of Jilin University, Changchun, China
| | - Jing Jie
- Department of Respiratory Medicine, Center for Infectious Diseases and Pathogen Biology, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, State Key Laboratory for Zoonotic Diseases, The First Hospital of Jilin University, Changchun, China
| | - Yu Sun
- The First Hospital of Jilin University, Changchun, China
| | - Qingtian Guan
- The First Hospital of Jilin University, Changchun, China
| | - Dan Li
- Department of Respiratory Medicine, Center for Infectious Diseases and Pathogen Biology, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, State Key Laboratory for Zoonotic Diseases, The First Hospital of Jilin University, Changchun, China
| | - Zhao-Qing Luo
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, USA
| | - Lei Song
- Department of Respiratory Medicine, Center for Infectious Diseases and Pathogen Biology, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, State Key Laboratory for Zoonotic Diseases, The First Hospital of Jilin University, Changchun, China
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Nimma R, Kumar A, Gani Z, Gahlawat A, Dilawari R, Rohilla RK, Kumbhar H, Garg P, Chopra S, Raje M, Iyengar Raje C. Characterization of the enzymatic and multifunctional properties of Acinetobacter baumannii erythrose-4-phosphate dehydrogenase (E4PDH). Microb Pathog 2023; 175:105992. [PMID: 36649779 DOI: 10.1016/j.micpath.2023.105992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 01/04/2023] [Accepted: 01/13/2023] [Indexed: 01/15/2023]
Abstract
Infections due to Acinetobacter baumannii (A. baumannii) are rapidly increasing worldwide and consequently therapeutic options for treatment are limited. The emergence of multi drug resistant (MDR) strains has rendered available antibiotics ineffective, necessitating the urgent discovery of new drugs and drug targets. The vitamin B6 biosynthetic pathway has been considered as a potential antibacterial drug target but it is as yet uncharacterized for A. baumannii. In the current work, we have carried out in silico and biochemical characterization of Erythrose-4-phosphate dehydrogenase (E4PDH) (EC 1.2.1.72). This enzyme catalyzes the first step in the deoxyxylulose-5-phosphate (DXP) dependent Vitamin B6 biosynthetic pathway i.e. the conversion of d-erythrose-4-phosphate (E4P) to 4-Phosphoerythronate. E4PDH also possesses an additional activity whereby it can catalyze the conversion of Glyceraldehyde-3-phosphate (G3P) to 1,3 bisphosphoglycerate (1,3BPG). Our studies have revealed that this enzyme exhibits an alternate moonlighting function as a cell surface receptor for the human iron transport proteins transferrin (Tf) and lactoferrin (Lf). The present work reports the internalization of Tf and consequent iron acquisition as an alternate strategy for iron acquisition. Given its essential role in two crucial pathways i.e. metabolism and iron acquisition, A. baumannii E4PDH may play a vital role in bacterial pathogenesis.
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Affiliation(s)
- Ramesh Nimma
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research (NIPER), SAS Nagar, Punjab, 160062, India
| | - Ajay Kumar
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research (NIPER), SAS Nagar, Punjab, 160062, India
| | - Zahid Gani
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research (NIPER), SAS Nagar, Punjab, 160062, India
| | - Anuj Gahlawat
- Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research (NIPER), SAS Nagar, Punjab, 160062, India
| | - Rahul Dilawari
- Council of Scientific and Industrial Research-Institute of Microbial Technology (CSIR-IMTECH), Sector 39A, Chandigarh, 160036, India
| | - Rajesh Kumar Rohilla
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research (NIPER), SAS Nagar, Punjab, 160062, India
| | - Hemangi Kumbhar
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research (NIPER), SAS Nagar, Punjab, 160062, India
| | - Prabha Garg
- Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research (NIPER), SAS Nagar, Punjab, 160062, India
| | - Sidharth Chopra
- Council of Scientific and Industrial Research-CSIR (CSIR-CDRI), Sector10, Janakipuram Extension, Sitapur Road, Lucknow, 226031, UP, India
| | - Manoj Raje
- Council of Scientific and Industrial Research-Institute of Microbial Technology (CSIR-IMTECH), Sector 39A, Chandigarh, 160036, India
| | - Chaaya Iyengar Raje
- Department of Biotechnology, National Institute of Pharmaceutical Education and Research (NIPER), SAS Nagar, Punjab, 160062, India.
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Ishiai T, Subsomwong P, Narita K, Kawai N, Teng W, Suzuki S, Sukchawalit R, Nakane A, Asano K. Extracellular vesicles of Pseudomonas aeruginosa downregulate pyruvate fermentation enzymes and inhibit the initial growth of Staphylococcus aureus. CURRENT RESEARCH IN MICROBIAL SCIENCES 2023; 4:100190. [PMID: 37131486 PMCID: PMC10149184 DOI: 10.1016/j.crmicr.2023.100190] [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] [Indexed: 05/04/2023] Open
Abstract
Staphylococcus aureus and Pseudomonas aeruginosa are well-known opportunistic pathogens that frequently coexist in chronic wounds and cystic fibrosis. The exoproducts of P. aeruginosa have been shown to affect the growth and pathogenicity of S. aureus, but the detailed mechanisms are not well understood. In this study, we investigated the effect of extracellular vesicles from P. aeruginosa (PaEVs) on the growth of S. aureus. We found that PaEVs inhibited the S. aureus growth independently of iron chelation and showed no bactericidal activity. This growth inhibitory effect was also observed with methicillin-resistant S. aureus but not with Acinetobacter baumannii, Enterococcus faecalis, S. Typhimurium, E. coli, Listeria monocytogenes, or Candida albicans, suggesting that the growth inhibitory effect of PaEVs is highly specific for S. aureus. To better understand the detailed mechanism, the difference in protein production of S. aureus between PaEV-treated and non-treated groups was further analyzed. The results revealed that lactate dehydrogenase 2 and formate acetyltransferase enzymes in the pyruvate fermentation pathway were significantly reduced after PaEV treatment. Likewise, the expression of ldh2 gene for lactate dehydrogenase 2 and pflB gene for formate acetyltransferase in S. aureus was reduced by PaEV treatment. In addition, this inhibitory effect of PaEVs was abolished by supplementation with pyruvate or oxygen. These results suggest that PaEVs inhibit the growth of S. aureus by suppressing the pyruvate fermentation pathway. This study reported a mechanism of PaEVs in inhibiting S. aureus growth which may be important for better management of S. aureus and P. aeruginosa co-infections.
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Affiliation(s)
- Takahito Ishiai
- Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
| | - Phawinee Subsomwong
- Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
| | - Kouj Narita
- Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
- Institute for Animal Experimentation, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
| | - Noriaki Kawai
- Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
| | - Wei Teng
- Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
| | - Sachio Suzuki
- Department of Respiratory Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
| | - Rojana Sukchawalit
- Laboratory of Biotechnology, Chulabhorn Research Institute, Lak Si, Bangkok 10210, Thailand
| | - Akio Nakane
- Department of Biopolymer and Health Science, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 306-8562, Japan
| | - Krisana Asano
- Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 036-8562, Japan
- Department of Biopolymer and Health Science, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori 306-8562, Japan
- Corresponding author at: Department of Microbiology and Immunology, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki, 036-8562, Japan.
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Multidrug-Resistant Acinetobacter baumannii Infections in the United Kingdom versus Egypt: Trends and Potential Natural Products Solutions. Antibiotics (Basel) 2023; 12:antibiotics12010077. [PMID: 36671278 PMCID: PMC9854726 DOI: 10.3390/antibiotics12010077] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 12/19/2022] [Accepted: 12/21/2022] [Indexed: 01/03/2023] Open
Abstract
Acinetobacter baumannii is a problematic pathogen of global concern. It causes multiple types of infection, especially among immunocompromised individuals in intensive care units. One of the most serious concerns related to this pathogen is its ability to become resistant to almost all the available antibiotics used in clinical practice. Moreover, it has a great tendency to spread this resistance at a very high rate, crossing borders and affecting healthcare settings across multiple economic levels. In this review, we trace back the reported incidences in the PubMed and the Web of Science databases of A. baumannii infections in both the United Kingdom and Egypt as two representative examples for countries of two different economic levels: high and low-middle income countries. Additionally, we compare the efforts made by researchers from both countries to find solutions to the lack of available treatments by looking into natural products reservoirs. A total of 113 studies reporting infection incidence were included, with most of them being conducted in Egypt, especially the recent ones. On the one hand, this pathogen was detected in the UK many years before it was reported in Egypt; on the other hand, the contribution of Egyptian researchers to identifying a solution using natural products is more notable than that of researchers in the UK. Tracing the prevalence of A. baumannii infections over the years showed that the infections are on the rise, especially in Egypt vs. the UK. Further concerns are linked to the spread of antibiotic resistance among the isolates collected from Egypt reaching very alarming levels. Studies conducted in the UK showed earlier inclusion of high-throughput technologies in the tracking and detection of A. baumannii and its resistance than those conducted in Egypt. Possible explanations for these variations are analyzed and discussed.
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How GBS Got Its Hump: Genomic Analysis of Group B Streptococcus from Camels Identifies Host Restriction as well as Mobile Genetic Elements Shared across Hosts and Pathogens. Pathogens 2022; 11:pathogens11091025. [PMID: 36145457 PMCID: PMC9504112 DOI: 10.3390/pathogens11091025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 09/02/2022] [Accepted: 09/05/2022] [Indexed: 11/23/2022] Open
Abstract
Group B Streptococcus (GBS) literature largely focuses on humans and neonatal disease, but GBS also affects numerous animals, with significant impacts on health and productivity. Spill-over events occur between humans and animals and may be followed by amplification and evolutionary adaptation in the new niche, including changes in the core or accessory genome content. Here, we describe GBS from one-humped camels (Camelus dromedarius), a relatively poorly studied GBS host of increasing importance for food security in arid regions. Genomic analysis shows that virtually all GBS from camels in East Africa belong to a monophyletic clade, sublineage (SL)609. Capsular types IV and VI, including a new variant of type IV, were over-represented compared to other host species. Two genomic islands with signatures of mobile elements contained most camel-associated genes, including genes for metal and carbohydrate utilisation. Lactose fermentation genes were associated with milk isolates, albeit at lower prevalence in camel than bovine GBS. The presence of a phage with high identity to Streptococcus pneumoniae and Streptococcus suis suggests lateral gene transfer between GBS and bacterial species that have not been described in camels. The evolution of camel GBS appears to combine host restriction with the sharing of accessory genome content across pathogen and host species.
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11
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Synthesis and Characterization of Preacinetobactin and 5-Phenyl Preacinetobactin. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27123688. [PMID: 35744823 PMCID: PMC9227331 DOI: 10.3390/molecules27123688] [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: 05/05/2022] [Revised: 05/30/2022] [Accepted: 06/06/2022] [Indexed: 11/17/2022]
Abstract
We report the first total synthesis of 5-phenyl preacinetobactin and its characterization. The route was developed for the synthesis of preacinetobactin, the siderophore critical to the Gram-negative pathogen A. baumannii. It leverages a C5-substituted benzaldehyde as a key starting material and should enable the synthesis of similar analogs. 5-Phenyl preacinetobactin binds iron in a manner analogous to the natural siderophore, but it did not rescue growth in a strain of A. baumannii unable to produce preacinetobactin.
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12
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Djahanschiri B, Di Venanzio G, Distel JS, Breisch J, Dieckmann MA, Goesmann A, Averhoff B, Göttig S, Wilharm G, Feldman MF, Ebersberger I. Evolutionarily stable gene clusters shed light on the common grounds of pathogenicity in the Acinetobacter calcoaceticus-baumannii complex. PLoS Genet 2022; 18:e1010020. [PMID: 35653398 PMCID: PMC9162365 DOI: 10.1371/journal.pgen.1010020] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 04/04/2022] [Indexed: 11/19/2022] Open
Abstract
Nosocomial pathogens of the Acinetobacter calcoaceticus-baumannii (ACB) complex are a cautionary example for the world-wide spread of multi- and pan-drug resistant bacteria. Aiding the urgent demand for novel therapeutic targets, comparative genomics studies between pathogens and their apathogenic relatives shed light on the genetic basis of human-pathogen interaction. Yet, existing studies are limited in taxonomic scope, sensing of the phylogenetic signal, and resolution by largely analyzing genes independent of their organization in functional gene clusters. Here, we explored more than 3,000 Acinetobacter genomes in a phylogenomic framework integrating orthology-based phylogenetic profiling and microsynteny conservation analyses. We delineate gene clusters in the type strain A. baumannii ATCC 19606 whose evolutionary conservation indicates a functional integration of the subsumed genes. These evolutionarily stable gene clusters (ESGCs) reveal metabolic pathways, transcriptional regulators residing next to their targets but also tie together sub-clusters with distinct functions to form higher-order functional modules. We shortlisted 150 ESGCs that either co-emerged with the pathogenic ACB clade or are preferentially found therein. They provide a high-resolution picture of genetic and functional changes that coincide with the manifestation of the pathogenic phenotype in the ACB clade. Key innovations are the remodeling of the regulatory-effector cascade connecting LuxR/LuxI quorum sensing via an intermediate messenger to biofilm formation, the extension of micronutrient scavenging systems, and the increase of metabolic flexibility by exploiting carbon sources that are provided by the human host. We could show experimentally that only members of the ACB clade use kynurenine as a sole carbon and energy source, a substance produced by humans to fine-tune the antimicrobial innate immune response. In summary, this study provides a rich and unbiased set of novel testable hypotheses on how pathogenic Acinetobacter interact with and ultimately infect their human host. It is a comprehensive resource for future research into novel therapeutic strategies. The spread of multi- and pan-drug resistant bacterial pathogens is a worldwide threat to human health. Understanding the genetics of host colonization and infection can substantially help in devising novel ways of treatment. Acinetobacter baumannii, a nosocomial pathogen ranked top by the World Health Organization in the list of bacteria for which novel therapeutic approaches are needed, is a prime example. Here, we have carved out the genetic make-up that distinguishes A. baumannii and its pathogenic next relatives from other and mostly apathogenic Acinetobacter species. We found a rich spectrum of pathways and regulatory modules that reveal how the pathogens have modified biofilm formation, iron scavenging, and their carbohydrate metabolism to adapt to their human host. Among these, the capability to metabolize kynurenine is particularly intriguing. Humans produce this substance to contain bacterial invaders and to fine-tune the innate immune response. But A. baumannii and closely related pathogens found a way to feed on kynurenine. This suggests that the pathogens might be able to dysregulate the human immune response. In summary, our study substantially deepens the understanding of how a highly critical pathogen interacts with its host, which substantially eases the identification of novel targets for innovative therapeutic strategies.
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Affiliation(s)
- Bardya Djahanschiri
- Applied Bioinformatics Group, Inst. of Cell Biology and Neuroscience, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Gisela Di Venanzio
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, Missouri, United States of America
| | - Jesus S. Distel
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, Missouri, United States of America
| | - Jennifer Breisch
- Inst. of Molecular Biosciences, Department of Molecular Microbiology and Bioenergetics, Goethe University Frankfurt, Frankfurt am Main, Germany
| | | | - Alexander Goesmann
- Bioinformatics and Systems Biology, Justus Liebig University Gießen, Gießen, Germany
| | - Beate Averhoff
- Inst. of Molecular Biosciences, Department of Molecular Microbiology and Bioenergetics, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Stephan Göttig
- Institute for Medical Microbiology and Infection Control, University Hospital, Goethe University, Frankfurt, Germany
| | | | - Mario F. Feldman
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, Missouri, United States of America
| | - Ingo Ebersberger
- Applied Bioinformatics Group, Inst. of Cell Biology and Neuroscience, Goethe University Frankfurt, Frankfurt am Main, Germany
- Senckenberg Biodiversity and Climate Research Centre (S-BIKF), Frankfurt am Main, Germany
- LOEWE Center for Translational Biodiversity Genomics (TBG), Frankfurt am Main, Germany
- * E-mail:
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13
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Hubloher JJ, van der Sande L, Müller V. Na + homeostasis in Acinetobacter baumannii is facilitated via the activity of the Mrp antiporter. Environ Microbiol 2022; 24:4411-4424. [PMID: 35535800 DOI: 10.1111/1462-2920.16039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 04/26/2022] [Accepted: 05/04/2022] [Indexed: 11/30/2022]
Abstract
The human opportunistic pathogen Acinetobacter baumannii is a global threat to healthcare institutions worldwide, since it developed very efficient strategies to evade host defense and to adapt to the different environmental conditions of the host. This worked focused on the importance of Na+ homeostasis in A. baumannii with regards to pathobiological aspects. In silico studies revealed a homologue of a multicomponent Na+ /H+ antiporter system. Inactivation of the Mrp antiporter through deletion of the first gene (mrpA') resulted in a mutant that was sensitive to increasing pH values. Furthermore, the strain was highly sensitive to increasing Na+ and Li+ concentrations. Increasing Na+ sensitivity is thought to be responsible for growth impairment in human fluids. Furthermore, deletion of mrpA' is associated with energetic defects, inhibition of motility and survival under anoxic and dry conditions.
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Affiliation(s)
- Josephine Joy Hubloher
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Goethe-University Frankfurt am Main, Germany
| | - Lisa van der Sande
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Goethe-University Frankfurt am Main, Germany
| | - Volker Müller
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Goethe-University Frankfurt am Main, Germany
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14
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Aliyu H, de Maayer P, Neumann A. Not All That Glitters Is Gold: The Paradox of CO-dependent Hydrogenogenesis in Parageobacillus thermoglucosidasius. Front Microbiol 2021; 12:784652. [PMID: 34956151 PMCID: PMC8696081 DOI: 10.3389/fmicb.2021.784652] [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: 09/28/2021] [Accepted: 11/05/2021] [Indexed: 11/13/2022] Open
Abstract
The thermophilic bacterium Parageobacillus thermoglucosidasius has recently gained interest due to its ability to catalyze the water gas shift reaction, where the oxidation of carbon monoxide (CO) is linked to the evolution of hydrogen (H2) gas. This phenotype is largely predictable based on the presence of a genomic region coding for a carbon monoxide dehydrogenase (CODH-Coo) and hydrogen evolving hydrogenase (Phc). In this work, seven previously uncharacterized strains were cultivated under 50% CO and 50% air atmosphere. Despite the presence of the coo-phc genes in all seven strains, only one strain, Kp1013, oxidizes CO and yields H2. The genomes of the H2 producing strains contain unique genomic regions that code for proteins involved in nickel transport and the detoxification of catechol, a by-product of a siderophore-mediated iron acquisition system. Combined, the presence of these genomic regions could potentially drive biological water gas shift (WGS) reaction in P. thermoglucosidasius.
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Affiliation(s)
- Habibu Aliyu
- Institute of Process Engineering in Life Science 2 – Technical Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Pieter de Maayer
- School of Molecular and Cell Biology, Faculty of Science, University of the Witwatersrand, Johannesburg, South Africa
| | - Anke Neumann
- Institute of Process Engineering in Life Science 2 – Technical Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany
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15
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CsrA Coordinates Compatible Solute Synthesis in Acinetobacter baumannii and Facilitates Growth in Human Urine. Microbiol Spectr 2021; 9:e0129621. [PMID: 34730379 PMCID: PMC8567240 DOI: 10.1128/spectrum.01296-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
CsrA is a global regulator widespread in bacteria and known to be involved in different physiological processes, including pathogenicity. Deletion of csrA of Acinetobacter baumannii strain ATCC 19606 resulted in a mutant that was unable to utilize a broad range of carbon and energy sources, including amino acids. This defect in amino acid metabolism was most likely responsible for the growth inhibition of the ΔcsrA mutant in human urine, where amino acids are the most abundant carbon source for A. baumannii. Recent studies revealed that deletion of csrA in the A. baumannii strains AB09-003 and ATCC 17961 resulted in an increase in hyperosmotic stress resistance. However, the molecular basis for this observation remained unknown. This study aimed to investigate the role of CsrA in compatible solute synthesis. We observed striking differences in the ability of different A. baumannii strains to cope with hyperosmotic stress. Strains AB09-003 and ATCC 17961 were strongly impaired in hyperosmotic stress resistance in comparison to strain ATCC 19606. These differences were abolished by deletion of csrA and are in line with the ability to synthesize compatible solutes. In the salt-sensitive strains AB09-003 and ATCC 17961, compatible solute synthesis was repressed by CsrA. This impairment is mediated via CsrA and could be overcome by deletion of csrA from the genome. IMPORTANCE The opportunistic human pathogen Acinetobacter baumannii has become one of the leading causes of nosocomial infections around the world due to the increasing prevalence of multidrug-resistant strains and their optimal adaptation to clinical environments and the human host. Recently, it was found that CsrA, a global mRNA binding posttranscriptional regulator, plays a role in osmotic stress adaptation, virulence, and growth on amino acids of A. baumannii AB09-003 and ATCC 17961. Here, we report that this is also the case for A. baumannii ATCC 19606. However, we observed significant differences in the ΔcsrA mutants with respect to osmostress resistance, such as the AB09-003 and 17961 mutants being enhanced in osmostress resistance whereas the ATCC 19606 mutant was not. This suggests that the role of CsrA in osmotic stress adaptation is strain specific. Furthermore, we provide clear evidence that CsrA is essential for growth in human urine and at high temperatures.
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16
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The intracellular phase of extracellular respiratory tract bacterial pathogens and its role on pathogen-host interactions during infection. Curr Opin Infect Dis 2021; 34:197-205. [PMID: 33899754 DOI: 10.1097/qco.0000000000000727] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
PURPOSE OF REVIEW An initial intracellular phase of usually extracellular bacterial pathogens displays an important strategy to hide from the host's immune system and antibiotics therapy. It helps the bacteria, including bacterial pathogens of airway diseases, to persist and eventually switch to a typical extracellular infection. Several infectious diseases of the lung are life-threatening and their control is impeded by intracellular persistence of pathogens. Thus, molecular adaptations of the pathogens to this niche but also the host's response and potential targets to interfere are of relevance. Here we discuss examples of historically considered extracellular pathogens of the respiratory airway where the intracellular survival and proliferation is well documented, including infections by Staphylococcus aureus, Bordetella pertussis, Haemophilus influenzae, Pseudomonas aeruginosa, and others. RECENT FINDINGS Current studies focus on bacterial factors contributing to adhesion, iron acquisition, and intracellular survival as well as ways to target them for combatting the bacterial infections. SUMMARY The investigation of common and specific mechanisms of pathogenesis and persistence of these bacteria in the host may contribute to future investigations and identifications of relevant factors and/or bacterial mechanisms to be blocked to treat or improve prevention strategies.
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17
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Valentino H, Korasick DA, Bohac TJ, Shapiro JA, Wencewicz TA, Tanner JJ, Sobrado P. Structural and Biochemical Characterization of the Flavin-Dependent Siderophore-Interacting Protein from Acinetobacter baumannii. ACS OMEGA 2021; 6:18537-18547. [PMID: 34308084 PMCID: PMC8296543 DOI: 10.1021/acsomega.1c03047] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 06/23/2021] [Indexed: 05/09/2023]
Abstract
Acinetobacter baumannii is an opportunistic pathogen with a high mortality rate due to multi-drug-resistant strains. The synthesis and uptake of the iron-chelating siderophores acinetobactin (Acb) and preacinetobactin (pre-Acb) have been shown to be essential for virulence. Here, we report the kinetic and structural characterization of BauF, a flavin-dependent siderophore-interacting protein (SIP) required for the reduction of Fe(III) bound to Acb/pre-Acb and release of Fe(II). Stopped-flow spectrophotometric studies of the reductive half-reaction show that BauF forms a stable neutral flavin semiquinone intermediate. Reduction with NAD(P)H is very slow (k obs, 0.001 s-1) and commensurate with the rate of reduction by photobleaching, suggesting that NAD(P)H are not the physiological partners of BauF. The reduced BauF was oxidized by Acb-Fe (k obs, 0.02 s-1) and oxazole pre-Acb-Fe (ox-pre-Acb-Fe) (k obs, 0.08 s-1), a rigid analogue of pre-Acb, at a rate 3-11 times faster than that with molecular oxygen alone. The structure of FAD-bound BauF was solved at 2.85 Å and was found to share a similarity to Shewanella SIPs. The biochemical and structural data presented here validate the role of BauF in A. baumannii iron assimilation and provide information important for drug design.
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Affiliation(s)
- Hannah Valentino
- Department
of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - David A. Korasick
- Department
of Biochemistry, University of Missouri, Columbia, Missouri 65211, United States
| | - Tabbetha J. Bohac
- Department
of Chemistry, Washington University in Saint
Louis, St. Louis, Missouri 63130, United States
| | - Justin A. Shapiro
- Department
of Chemistry, Washington University in Saint
Louis, St. Louis, Missouri 63130, United States
| | - Timothy A. Wencewicz
- Department
of Chemistry, Washington University in Saint
Louis, St. Louis, Missouri 63130, United States
| | - John J. Tanner
- Department
of Biochemistry, University of Missouri, Columbia, Missouri 65211, United States
- Department
of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
| | - Pablo Sobrado
- Department
of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
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18
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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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19
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Ma C, McClean S. Mapping Global Prevalence of Acinetobacter baumannii and Recent Vaccine Development to Tackle It. Vaccines (Basel) 2021; 9:vaccines9060570. [PMID: 34205838 PMCID: PMC8226933 DOI: 10.3390/vaccines9060570] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 05/16/2021] [Accepted: 05/22/2021] [Indexed: 12/23/2022] Open
Abstract
Acinetobacter baumannii is a leading cause of nosocomial infections that severely threaten public health. The formidable adaptability and resistance of this opportunistic pathogen have hampered the development of antimicrobial therapies which consequently leads to very limited treatment options. We mapped the global prevalence of multidrug-resistant A. baumannii and showed that carbapenem-resistant A. baumannii is widespread throughout Asia and the Americas. Moreover, when antimicrobial resistance rates of Acinetobacter spp. exceed a threshold level, the proportion of A. baumannii isolates from clinical samples surges. Therefore, vaccines represent a realistic alternative strategy to tackle this pathogen. Research into anti-A. baumannii vaccines have enhanced in the past decade and multiple antigens have been investigated preclinically with varying results. This review summarises the current knowledge of virulence factors relating to A. baumannii–host interactions and its implication in vaccine design, with a view to understanding the current state of A. baumannii vaccine development and the direction of future efforts.
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20
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Klebba PE, Newton SMC, Six DA, Kumar A, Yang T, Nairn BL, Munger C, Chakravorty S. Iron Acquisition Systems of Gram-negative Bacterial Pathogens Define TonB-Dependent Pathways to Novel Antibiotics. Chem Rev 2021; 121:5193-5239. [PMID: 33724814 PMCID: PMC8687107 DOI: 10.1021/acs.chemrev.0c01005] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Iron is an indispensable metabolic cofactor in both pro- and eukaryotes, which engenders a natural competition for the metal between bacterial pathogens and their human or animal hosts. Bacteria secrete siderophores that extract Fe3+ from tissues, fluids, cells, and proteins; the ligand gated porins of the Gram-negative bacterial outer membrane actively acquire the resulting ferric siderophores, as well as other iron-containing molecules like heme. Conversely, eukaryotic hosts combat bacterial iron scavenging by sequestering Fe3+ in binding proteins and ferritin. The variety of iron uptake systems in Gram-negative bacterial pathogens illustrates a range of chemical and biochemical mechanisms that facilitate microbial pathogenesis. This document attempts to summarize and understand these processes, to guide discovery of immunological or chemical interventions that may thwart infectious disease.
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Affiliation(s)
- Phillip E Klebba
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Salete M C Newton
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506, United States
| | - David A Six
- Venatorx Pharmaceuticals, Inc., 30 Spring Mill Drive, Malvern, Pennsylvania 19355, United States
| | - Ashish Kumar
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Taihao Yang
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Brittany L Nairn
- Department of Biological Sciences, Bethel University, 3900 Bethel Drive, St. Paul, Minnesota 55112, United States
| | - Colton Munger
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Somnath Chakravorty
- Jacobs School of Medicine and Biomedical Sciences, SUNY Buffalo, Buffalo, New York 14203, United States
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21
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Martinez J, Razo-Gutierrez C, Le C, Courville R, Pimentel C, Liu C, Fung SE, Tuttobene MR, Phan K, Vila AJ, Shahrestani P, Jimenez V, Tolmasky ME, Becka SA, Papp-Wallace KM, Bonomo RA, Soler-Bistue A, Sieira R, Ramirez MS. Cerebrospinal fluid (CSF) augments metabolism and virulence expression factors in Acinetobacter baumannii. Sci Rep 2021; 11:4737. [PMID: 33637791 PMCID: PMC7910304 DOI: 10.1038/s41598-021-81714-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 01/06/2021] [Indexed: 12/14/2022] Open
Abstract
In a recent report by the Centers for Disease Control and Prevention (CDC), multidrug resistant (MDR) Acinetobacter baumannii is a pathogen described as an "urgent threat." Infection with this bacterium manifests as different diseases such as community and nosocomial pneumonia, bloodstream infections, endocarditis, infections of the urinary tract, wound infections, burn infections, skin and soft tissue infections, and meningitis. In particular, nosocomial meningitis, an unwelcome complication of neurosurgery caused by extensively-drug resistant (XDR) A. baumannii, is extremely challenging to manage. Therefore, understanding how A. baumannii adapts to different host environments, such as cerebrospinal fluid (CSF) that may trigger changes in expression of virulence factors that are associated with the successful establishment and progress of this infection is necessary. The present in-vitro work describes, the genetic changes that occur during A. baumannii infiltration into CSF and displays A. baumannii's expansive versatility to persist in a nutrient limited environment while enhancing several virulence factors to survive and persist. While a hypervirulent A. baumannii strain did not show changes in its transcriptome when incubated in the presence of CSF, a low-virulence isolate showed significant differences in gene expression and phenotypic traits. Exposure to 4% CSF caused increased expression of virulence factors such as fimbriae, pilins, and iron chelators, and other virulence determinants that was confirmed in various model systems. Furthermore, although CSF's presence did not enhance bacterial growth, an increase of expression of genes encoding transcription, translation, and the ATP synthesis machinery was observed. This work also explores A. baumannii's response to an essential component, human serum albumin (HSA), within CSF to trigger the differential expression of genes associated with its pathoadaptibility in this environment.
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Affiliation(s)
- Jasmine Martinez
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Chelsea Razo-Gutierrez
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Casin Le
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Robert Courville
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Camila Pimentel
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Christine Liu
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Sammie E Fung
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Marisel R Tuttobene
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Kimberly Phan
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Alejandro J Vila
- Instituto de Biología Molecular Y Celular de Rosario (IBR, CONICET-UNR), Rosario, Argentina
- Área Biofísica, Facultad de Ciencias Bioquímicas Y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Parvin Shahrestani
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Veronica Jimenez
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Marcelo E Tolmasky
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA
| | - Scott A Becka
- Research Service and GRECC, Department of Veterans Affairs Medical Center, Louis Stokes Cleveland, Cleveland, OH, USA
| | - Krisztina M Papp-Wallace
- Research Service and GRECC, Department of Veterans Affairs Medical Center, Louis Stokes Cleveland, Cleveland, OH, USA
- Departments of Medicine, Pharmacology, Molecular Biology and Microbiology, Biochemistry, Proteomics and Bioinformatics, Case Western Reserve University School of Medicine, Cleveland, OH, USA
- CWRU-Cleveland VAMC Center for Antimicrobial Resistance and Epidemiology (Case VA CARES), Cleveland, OH, USA
| | - Robert A Bonomo
- Research Service and GRECC, Department of Veterans Affairs Medical Center, Louis Stokes Cleveland, Cleveland, OH, USA
- Departments of Medicine, Pharmacology, Molecular Biology and Microbiology, Biochemistry, Proteomics and Bioinformatics, Case Western Reserve University School of Medicine, Cleveland, OH, USA
- CWRU-Cleveland VAMC Center for Antimicrobial Resistance and Epidemiology (Case VA CARES), Cleveland, OH, USA
| | - Alfonso Soler-Bistue
- Instituto de Investigaciones Biotecnológicas, Universidad Nacional de San Martín-Consejo Nacional de Investigaciones Científicas Y Técnicas, San Martín, Buenos Aires, Argentina
| | - Rodrigo Sieira
- Fundación Instituto Leloir - IIBBA CONICET, Buenos Aires, Argentina
| | - Maria Soledad Ramirez
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, 800 N State College Blvd, Fullerton, CA, 92831, USA.
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22
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Ramezanalizadeh F, Rasooli I, Owlia P. Protective response against Acinetobacter baumannii with ferric iron receptors HemTR-BauA in a murine sepsis model. Future Microbiol 2021; 16:143-157. [PMID: 33528272 DOI: 10.2217/fmb-2020-0133] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Aim: Iron uptake and metabolism pathways are promising targets in vaccine development as an alternative strategy for antibiotics. Methods & methods: HemTR, a putative heme receptor of Acinetobacter baumannii, was expressed and its protectivity against A. baumannii was determined singly or in combination with the siderophore receptor, BauA, in mice. Results: High level of IgG was elicited. There was a delay in mice mortality with reduced bacterial loads in internal organs in the sublethal challenge. Protection was better in the HemTR-BauA group in both lethal and sublethal challenges. Passive transfer of anti-HemTR and anti-BauA partially protected mice against A. baumannii infection. Conclusion: HemTR in combination with other iron receptors could contribute to the development of protective vaccines against A. baumannii.
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Affiliation(s)
| | - Iraj Rasooli
- Department of Biology, Molecular Microbiology Research Center, Shahed University, Tehran, 3319118651, Iran
| | - Parviz Owlia
- Department of Microbiology, Molecular Microbiology Research Center, School of Medicine, Shahed University, Tehran, 3319118651, Iran
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23
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Kim N, Kim HJ, Oh MH, Kim SY, Kim MH, Son JH, Kim SI, Shin M, Lee YC, Lee JC. The role of Zur-regulated lipoprotein A in bacterial morphology, antimicrobial susceptibility, and production of outer membrane vesicles in Acinetobacter baumannii. BMC Microbiol 2021; 21:27. [PMID: 33461493 PMCID: PMC7812711 DOI: 10.1186/s12866-020-02083-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 12/29/2020] [Indexed: 11/21/2022] Open
Abstract
Background Zinc uptake-regulator (Zur)-regulated lipoprotein A (ZrlA) plays a role in bacterial fitness and overcoming antimicrobial exposure in Acinetobacter baumannii. This study further characterized the zrlA gene and its encoded protein and investigated the roles of the zrlA gene in bacterial morphology, antimicrobial susceptibility, and production of outer membrane vesicles (OMVs) in A. baumannii ATCC 17978. Results In silico and polymerase chain reaction analyses showed that the zrlA gene was conserved among A. baumannii strains with 97–100% sequence homology. Recombinant ZrlA protein exhibited a specific enzymatic activity of D-alanine-D-alanine carboxypeptidase. Wild-type A. baumannii exhibited more morphological heterogeneity than a ΔzrlA mutant strain during stationary phase. The ΔzrlA mutant strain was more susceptible to gentamicin than the wild-type strain. Sizes and protein profiles of OMVs were similar between the wild-type and ΔzrlA mutant strains, but the ΔzrlA mutant strain produced 9.7 times more OMV particles than the wild-type strain. OMVs from the ΔzrlA mutant were more cytotoxic in cultured epithelial cells than OMVs from the wild-type strain. Conclusions The present study demonstrated that A. baumannii ZrlA contributes to bacterial morphogenesis and antimicrobial resistance, but its deletion increases OMV production and OMV-mediated host cell cytotoxicity. Supplementary Information The online version contains supplementary material available at 10.1186/s12866-020-02083-0.
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Affiliation(s)
- Nayeong Kim
- Department of Microbiology, School of Medicine, Kyungpook National University, 680 Gukchaebosang-ro, Jung-gu, Daegu, 41944, Republic of Korea
| | - Hyo Jeong Kim
- Department of Microbiology, School of Medicine, Kyungpook National University, 680 Gukchaebosang-ro, Jung-gu, Daegu, 41944, Republic of Korea
| | - Man Hwan Oh
- Department of Nanobiomedical Science, Dankook University, Cheonan, South Korea
| | - Se Yeon Kim
- Department of Microbiology, School of Medicine, Kyungpook National University, 680 Gukchaebosang-ro, Jung-gu, Daegu, 41944, Republic of Korea
| | - Mi Hyun Kim
- Department of Microbiology, School of Medicine, Kyungpook National University, 680 Gukchaebosang-ro, Jung-gu, Daegu, 41944, Republic of Korea
| | - Joo Hee Son
- Department of Microbiology, School of Medicine, Kyungpook National University, 680 Gukchaebosang-ro, Jung-gu, Daegu, 41944, Republic of Korea
| | - Seung Il Kim
- Drug & Disease Target Team, Korea Basic Science Institute, Ochang, South Korea.,Department of Bio-Analytical Science, University of Science and Technology (UST), Daejeon, South Korea
| | - Minsang Shin
- Department of Microbiology, School of Medicine, Kyungpook National University, 680 Gukchaebosang-ro, Jung-gu, Daegu, 41944, Republic of Korea
| | - Yoo Chul Lee
- Department of Microbiology, School of Medicine, Kyungpook National University, 680 Gukchaebosang-ro, Jung-gu, Daegu, 41944, Republic of Korea
| | - Je Chul Lee
- Department of Microbiology, School of Medicine, Kyungpook National University, 680 Gukchaebosang-ro, Jung-gu, Daegu, 41944, Republic of Korea.
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24
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Sheldon JR, Skaar EP. Acinetobacter baumannii can use multiple siderophores for iron acquisition, but only acinetobactin is required for virulence. PLoS Pathog 2020; 16:e1008995. [PMID: 33075115 PMCID: PMC7595644 DOI: 10.1371/journal.ppat.1008995] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 10/29/2020] [Accepted: 09/18/2020] [Indexed: 12/22/2022] Open
Abstract
Acinetobacter baumannii is an emerging pathogen that poses a global health threat due to a lack of therapeutic options for treating drug-resistant strains. In addition to acquiring resistance to last-resort antibiotics, the success of A. baumannii is partially due to its ability to effectively compete with the host for essential metals. Iron is fundamental in shaping host-pathogen interactions, where the host restricts availability of this nutrient in an effort to curtail bacterial proliferation. To circumvent restriction, pathogens possess numerous mechanisms to obtain iron, including through the use of iron-scavenging siderophores. A. baumannii elaborates up to ten distinct siderophores, encoded from three different loci: acinetobactin and pre-acinetobactin (collectively, acinetobactin), baumannoferrins A and B, and fimsbactins A-F. The expression of multiple siderophores is common amongst bacterial pathogens and often linked to virulence, yet the collective contribution of these siderophores to A. baumannii survival and pathogenesis has not been investigated. Here we begin dissecting functional redundancy in the siderophore-based iron acquisition pathways of A. baumannii. Excess iron inhibits overall siderophore production by the bacterium, and the siderophore-associated loci are uniformly upregulated during iron restriction in vitro and in vivo. Further, disrupting all of the siderophore biosynthetic pathways is necessary to drastically reduce total siderophore production by A. baumannii, together suggesting a high degree of functional redundancy between the metabolites. By contrast, inactivation of acinetobactin biosynthesis alone impairs growth on human serum, transferrin, and lactoferrin, and severely attenuates survival of A. baumannii in a murine bacteremia model. These results suggest that whilst A. baumannii synthesizes multiple iron chelators, acinetobactin is critical to supporting growth of the pathogen on host iron sources. Given the acinetobactin locus is highly conserved and required for virulence of A. baumannii, designing therapeutics targeting the biosynthesis and/or transport of this siderophore may represent an effective means of combating this pathogen.
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Affiliation(s)
- Jessica R. Sheldon
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Eric P. Skaar
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee, United States of America
- * E-mail:
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25
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Qin QM, Pei J, Gomez G, Rice-Ficht A, Ficht TA, de Figueiredo P. A Tractable Drosophila Cell System Enables Rapid Identification of Acinetobacter baumannii Host Factors. Front Cell Infect Microbiol 2020; 10:240. [PMID: 32528902 PMCID: PMC7264411 DOI: 10.3389/fcimb.2020.00240] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 04/27/2020] [Indexed: 12/11/2022] Open
Abstract
Acinetobacter baumannii is an important causative agent of nosocomial infections worldwide. The pathogen also readily acquires resistance to antibiotics, and pan-resistant strains have been reported. A. baumannii is widely regarded as an extracellular bacterial pathogen. However, accumulating evidence demonstrates that the pathogen can invade, survive or persist in infected mammalian cells. Unfortunately, the molecular mechanisms controlling these processes remain poorly understood. Here, we show that Drosophila S2 cells provide several attractive advantages as a model system for investigating the intracellular lifestyle of the pathogen, including susceptibility to bacterial intracellular replication and limited infection-induced host cell death. We also show that the Drosophila system can be used to rapidly identify host factors, including MAP kinase proteins, which confer susceptibility to intracellular parasitism. Finally, analysis of the Drosophila system suggested that host proteins that regulate organelle biogenesis and membrane trafficking contribute to regulating the intracellular lifestyle of the pathogen. Taken together, these findings establish a novel model system for elucidating interactions between A. baumannii and host cells, define new factors that regulate bacterial invasion or intracellular persistence, and identify subcellular compartments in host cells that interact with the pathogen.
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Affiliation(s)
- Qing-Ming Qin
- College of Plant Sciences, Key Laboratory of Zoonosis Research, Ministry of Education, Jilin University, Changchun, China.,Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, Bryan TX, United States
| | - Jianwu Pei
- Department of Veterinary Pathobiology, Texas A&M University, College Station, TX, United States
| | - Gabriel Gomez
- Department of Veterinary Pathobiology, Texas A&M University, College Station, TX, United States
| | - Allison Rice-Ficht
- Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, Bryan, TX, United States
| | - Thomas A Ficht
- Department of Veterinary Pathobiology, Texas A&M University, College Station, TX, United States
| | - Paul de Figueiredo
- Department of Microbial Pathogenesis and Immunology, Texas A&M Health Science Center, Bryan TX, United States.,Department of Veterinary Pathobiology, Texas A&M University, College Station, TX, United States.,Norman Borlaug Center, Texas A&M University, College Station, TX, United States
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26
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Ramirez MS, Bonomo RA, Tolmasky ME. Carbapenemases: Transforming Acinetobacter baumannii into a Yet More Dangerous Menace. Biomolecules 2020; 10:biom10050720. [PMID: 32384624 PMCID: PMC7277208 DOI: 10.3390/biom10050720] [Citation(s) in RCA: 115] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 04/27/2020] [Accepted: 04/29/2020] [Indexed: 02/07/2023] Open
Abstract
Acinetobacter baumannii is a common cause of serious nosocomial infections. Although community-acquired infections are observed, the vast majority occur in people with preexisting comorbidities. A. baumannii emerged as a problematic pathogen in the 1980s when an increase in virulence, difficulty in treatment due to drug resistance, and opportunities for infection turned it into one of the most important threats to human health. Some of the clinical manifestations of A. baumannii nosocomial infection are pneumonia; bloodstream infections; lower respiratory tract, urinary tract, and wound infections; burn infections; skin and soft tissue infections (including necrotizing fasciitis); meningitis; osteomyelitis; and endocarditis. A. baumannii has an extraordinary genetic plasticity that results in a high capacity to acquire antimicrobial resistance traits. In particular, acquisition of resistance to carbapenems, which are among the antimicrobials of last resort for treatment of multidrug infections, is increasing among A. baumannii strains compounding the problem of nosocomial infections caused by this pathogen. It is not uncommon to find multidrug-resistant (MDR, resistance to at least three classes of antimicrobials), extensively drug-resistant (XDR, MDR plus resistance to carbapenems), and pan-drug-resistant (PDR, XDR plus resistance to polymyxins) nosocomial isolates that are hard to treat with the currently available drugs. In this article we review the acquired resistance to carbapenems by A. baumannii. We describe the enzymes within the OXA, NDM, VIM, IMP, and KPC groups of carbapenemases and the coding genes found in A. baumannii clinical isolates.
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Affiliation(s)
- Maria Soledad Ramirez
- Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA 92831, USA;
| | - Robert A. Bonomo
- Medical Service and GRECC, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH 44106, USA;
- Departments of Medicine, Pharmacology, Molecular Biology and Microbiology, Biochemistry, Proteomics and Bioinformatics; Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
- WRU-Cleveland VAMC Center for Antimicrobial Resistance and Epidemiology (Case VA CARES), Cleveland, OH 44106, USA
| | - Marcelo E. Tolmasky
- Center for Applied Biotechnology Studies, Department of Biological Science, California State University Fullerton, Fullerton, CA 92831, USA;
- Correspondence: ; Tel.: +657-278-5263
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27
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Cameranesi MM, Paganini J, Limansky AS, Moran-Barrio J, Salcedo SP, Viale AM, Repizo GD. Acquisition of plasmids conferring carbapenem and aminoglycoside resistance and loss of surface-exposed macromolecule structures as strategies for the adaptation of Acinetobacter baumannii CC104 O/CC15 P strains to the clinical setting. Microb Genom 2020; 6. [PMID: 32213259 PMCID: PMC7643966 DOI: 10.1099/mgen.0.000360] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Acinetobacter baumannii (Aba) is an emerging opportunistic pathogen associated to nosocomial infections. The rapid increase in multidrug resistance (MDR) among Aba strains underscores the urgency of understanding how this pathogen evolves in the clinical environment. We conducted here a whole-genome sequence comparative analysis of three phylogenetically and epidemiologically related MDR Aba strains from Argentinean hospitals, assigned to the CC104O/CC15P clonal complex. While the Ab244 strain was carbapenem-susceptible, Ab242 and Ab825, isolated after the introduction of carbapenem therapy, displayed resistance to these last resource β-lactams. We found a high chromosomal synteny among the three strains, but significant differences at their accessory genomes. Most importantly, carbapenem resistance in Ab242 and Ab825 was attributed to the acquisition of a Rep_3 family plasmid carrying a blaOXA-58 gene. Other differences involved a genomic island carrying resistance to toxic compounds and a Tn10 element exclusive to Ab244 and Ab825, respectively. Also remarkably, 44 insertion sequences (ISs) were uncovered in Ab825, in contrast with the 14 and 11 detected in Ab242 and Ab244, respectively. Moreover, Ab825 showed a higher killing capacity as compared to the other two strains in the Galleria mellonella infection model. A search for virulence and persistence determinants indicated the loss or IS-mediated interruption of genes encoding many surface-exposed macromolecules in Ab825, suggesting that these events are responsible for its higher relative virulence. The comparative genomic analyses of the CC104O/CC15P strains conducted here revealed the contribution of acquired mobile genetic elements such as ISs and plasmids to the adaptation of A. baumannii to the clinical setting.
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Affiliation(s)
- María M Cameranesi
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET), Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Julian Paganini
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET), Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Adriana S Limansky
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET), Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Jorgelina Moran-Barrio
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET), Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Suzana P Salcedo
- Laboratory of Molecular Microbiology and Structural Biochemistry, CNRS UMR5086, University of Lyon, LyonF-69367, France
| | - Alejandro M Viale
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET), Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina
| | - Guillermo D Repizo
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET), Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina.,Laboratory of Molecular Microbiology and Structural Biochemistry, CNRS UMR5086, University of Lyon, LyonF-69367, France
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28
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Pires S, Peignier A, Seto J, Smyth DS, Parker D. Biological sex influences susceptibility to Acinetobacter baumannii pneumonia in mice. JCI Insight 2020; 5:132223. [PMID: 32191638 DOI: 10.1172/jci.insight.132223] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 03/11/2020] [Indexed: 12/31/2022] Open
Abstract
Acinetobacter baumannii (A. baumannii) is an extremely versatile multidrug-resistant pathogen with a very high mortality rate; therefore, it has become crucial to understand the host response during its infection. Given the importance of mice for modeling infection and their role in preclinical drug development, equal emphasis should be placed on the use of both sexes. Through our studies using a murine model of acute pneumonia with A. baumannii, we observed that female mice were more susceptible to infection. Likewise, treatment of male mice with estradiol increased their susceptibility to infection. Analysis of the airway compartment revealed enhanced inflammation and reduced neutrophil and alveolar macrophage numbers compared with male mice. Depletion of either neutrophils or alveolar macrophages was important for bacterial clearance; however, depletion of alveolar macrophages further exacerbated female susceptibility because of severe alterations in metabolic homeostasis. Our data highlight the importance of using both sexes when assessing host immune pathways.
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Affiliation(s)
- Sílvia Pires
- Department of Pathology, Immunology and Laboratory Medicine, Center for Immunity and Inflammation, Rutgers New Jersey Medical School, Newark, New Jersey, USA
| | - Adeline Peignier
- Department of Pathology, Immunology and Laboratory Medicine, Center for Immunity and Inflammation, Rutgers New Jersey Medical School, Newark, New Jersey, USA
| | - Jeremy Seto
- Department of Biological Sciences, New York City College of Technology, Brooklyn, New York, New York, USA
| | - Davida S Smyth
- Department of Natural Sciences, Eugene Lang College of Liberal Arts at The New School, New York, New York, USA
| | - Dane Parker
- Department of Pathology, Immunology and Laboratory Medicine, Center for Immunity and Inflammation, Rutgers New Jersey Medical School, Newark, New Jersey, USA
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29
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Kaur K, Sidhu H, Capalash N, Sharma P. Multicopper oxidase of Acinetobacter baumannii: Assessing its role in metal homeostasis, stress management and virulence. Microb Pathog 2020; 143:104124. [PMID: 32169492 DOI: 10.1016/j.micpath.2020.104124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 02/17/2020] [Accepted: 03/06/2020] [Indexed: 12/25/2022]
Abstract
A putative multicopper oxidase, encoded as CopA in the proteome of Acinetobacter baumannii 19606, and designated as AbMCO, was expressed heterologously in E. coli (pET-28a) and purified by Ni-NTA affinity chromatography. The purified AbMCO exhibited in vitro oxidase activities upon exogenous addition of ≥1 μM copper ions. Kinetic studies revealed its phenol oxidase activity as it could catalyze the oxidation of substrates viz. 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), guaiacol, pyrogallol and catechol. Additionally, AbMCO displayed siderophore oxidase activity which depicted its role in metal homeostasis and protection from the toxic redox states of copper and iron. Importantly, expression of abMCO increased manifold upon challenge with high concentrations of copper sulphate (CuSO4, 1.5 mM) and sodium chloride (NaCl, 700 mM) which suggested its protective role in stress adaptation and management. Intra-macrophage assay of abMCO-expressing and abMCO-non expressing cells depicted no significant change in the survival rate of A. baumannii inside the macrophages. These findings indicate that A. baumannii encodes a multicopper oxidase, conferring copper tolerance and survival under stress conditions but had no role in virulence of this pathogen.
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Affiliation(s)
- Kavleen Kaur
- Department of Microbiology, Panjab University, Chandigarh, India
| | - Harsimran Sidhu
- Department of Biotechnology, Panjab University, Chandigarh, India
| | - Neena Capalash
- Department of Biotechnology, Panjab University, Chandigarh, India
| | - Prince Sharma
- Department of Microbiology, Panjab University, Chandigarh, India.
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30
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Majumdar A, Trinh V, Moore KJ, Smallwood CR, Kumar A, Yang T, Scott DC, Long NJ, Newton SM, Klebba PE. Conformational rearrangements in the N-domain of Escherichia coli FepA during ferric enterobactin transport. J Biol Chem 2020; 295:4974-4984. [PMID: 32098871 DOI: 10.1074/jbc.ra119.011850] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 02/14/2020] [Indexed: 11/06/2022] Open
Abstract
The Escherichia coli outer membrane receptor FepA transports ferric enterobactin (FeEnt) by an energy- and TonB-dependent, but otherwise a mechanistically undetermined process involving its internal 150-residue N-terminal globular domain (N-domain). We genetically introduced pairs of Cys residues in different regions of the FepA tertiary structure, with the potential to form disulfide bonds. These included Cys pairs on adjacent β-strands of the N-domain (intra-N) and Cys pairs that bridged the external surface of the N-domain to the interior of the C-terminal transmembrane β-barrel (inter-N-C). We characterized FeEnt uptake by these mutants with siderophore nutrition tests, [59Fe]Ent binding and uptake experiments, and fluorescence decoy sensor assays. The three methods consistently showed that the intra-N disulfide bonds, which restrict conformational motion within the N-domain, prevented FeEnt uptake, whereas most inter-N-C disulfide bonds did not prevent FeEnt uptake. These outcomes indicate that conformational rearrangements must occur in the N terminus of FepA during FeEnt transport. They also argue against disengagement of the N-domain out of the channel as a rigid body and suggest instead that it remains within the transmembrane pore as FeEnt enters the periplasm.
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Affiliation(s)
- Aritri Majumdar
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506
| | - Vy Trinh
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma 73019
| | - Kyle J Moore
- Department of Chemistry, Physics and Engineering, Cameron University, Lawton, Oklahoma 73505
| | | | - Ashish Kumar
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506
| | - Taihao Yang
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506
| | - Daniel C Scott
- Howard Hughes Medical Institute, St. Jude Children's Research Hospital, Memphis, Tennessee 38105
| | - Noah J Long
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506
| | - Salete M Newton
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506
| | - Phillip E Klebba
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506
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31
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Zur-regulated lipoprotein A contributes to the fitness of Acinetobacter baumannii. J Microbiol 2020; 58:67-77. [DOI: 10.1007/s12275-020-9531-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 11/28/2019] [Accepted: 11/29/2019] [Indexed: 01/26/2023]
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32
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Mobarak Qamsari M, Rasooli I, Darvish Alipour Astaneh S. Identification and immunogenic properties of recombinant ZnuD protein loops of Acinetobacter baumannii. INFORMATICS IN MEDICINE UNLOCKED 2020. [DOI: 10.1016/j.imu.2020.100342] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
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33
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Lopez-Barbosa N, Suárez-Arnedo A, Cifuentes J, Gonzalez Barrios AF, Silvera Batista CA, Osma JF, Muñoz-Camargo C, Cruz JC. Magnetite-OmpA Nanobioconjugates as Cell-Penetrating Vehicles with Endosomal Escape Abilities. ACS Biomater Sci Eng 2019; 6:415-424. [PMID: 33463215 DOI: 10.1021/acsbiomaterials.9b01214] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Outer membrane protein A (OmpA) has been extensively studied in Gram-negative bacteria due to its relevance in the adhesion of pathogens to host cells and its surfactant capabilities. It consists of a hydrophobic β-barrel domain and a hydrophilic periplasmic domain, that confers OmpA an amphiphilic structure. This study aims to elucidate the capacity of Escherichia coli OmpA to translocate liposomal membranes and serve as a potential cell-penetrating vehicle. We immobilized OmpA on magnetite nanoparticles and investigated the possible functional changes exhibited by OmpA after immobilization. Liposomal intake was addressed using egg lecithin liposomes as a model, where magnetite-OmpA nanobioconjugates were able to translocate the liposomal membrane and caused a disruptive effect when subjected to a magnetic field. Nanobioconjugates showed both low cytotoxicity and hemolytic tendency. Additional interactions within the intracellular space led to altered viability results via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). Confocal microscopy images revealed that immobilized nanoparticles effectively enter the cytoplasm of THP-1 and Vero cells by different routes, and, subsequently, some escape endosomes, lysosomes, and other intracellular compartments with relatively high efficiencies. This was demonstrated by co-localization analyses with LysoTracker green that showed Pearson correlations of about 80 and 28%.
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Affiliation(s)
| | | | | | | | - Carlos A Silvera Batista
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
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34
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Human pleural fluid triggers global changes in the transcriptional landscape of Acinetobacter baumannii as an adaptive response to stress. Sci Rep 2019; 9:17251. [PMID: 31754169 PMCID: PMC6872806 DOI: 10.1038/s41598-019-53847-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 11/06/2019] [Indexed: 12/16/2022] Open
Abstract
Acinetobacter baumannii is a feared, drug-resistant pathogen, characterized by its ability to resist extreme environmental and nutrient-deprived conditions. Previously, we showed that human serum albumin (HSA) can increase foreign DNA acquisition specifically and alter the expression of genes associated with pathogenicity. Moreover, in a recent genome-wide transcriptomic study, we observed that pleural fluid (PF), an HSA-containing fluid, increases DNA acquisition, can modulate cytotoxicity, and control immune responses by eliciting changes in the A. baumannii metabolic profile. In the present work, using more stringent criteria and focusing on the analysis of genes related to pathogenicity and response to stress, we analyzed our previous RNA-seq data and performed phenotypic assays to further explore the impact of PF on A. baumannii's microbial behavior and the strategies used to overcome environmental stress. We observed that PF triggered differential expression of genes associated with motility, efflux pumps, antimicrobial resistance, biofilm formation, two-component systems (TCSs), capsule synthesis, osmotic stress, and DNA-damage response, among other categories. Phenotypic assays of A. baumannii A118 and two other clinical A. baumannii strains, revealed differences in their responses to PF in motility, biofilm formation, antibiotic susceptibility, osmotic stress, and outer membrane vesicle (OMV) production, suggesting that these changes are strain specific. We conclude that A. baumannii's pathoadaptive responses is induced by HSA-containing fluids and must be part of this bacterium armamentarium to persist in hostile environments.
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Rodman N, Martinez J, Fung S, Nakanouchi J, Myers AL, Harris CM, Dang E, Fernandez JS, Liu C, Mendoza AM, Jimenez V, Nikolaidis N, Brennan CA, Bonomo RA, Sieira R, Ramirez MS. Human Pleural Fluid Elicits Pyruvate and Phenylalanine Metabolism in Acinetobacter baumannii to Enhance Cytotoxicity and Immune Evasion. Front Microbiol 2019; 10:1581. [PMID: 31379769 PMCID: PMC6650585 DOI: 10.3389/fmicb.2019.01581] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 06/25/2019] [Indexed: 01/13/2023] Open
Abstract
Acinetobacter baumannii (Ab) is one of the most treacherous pathogens among those causing hospital-acquired pneumonia (HAP). A. baumannii possesses an adaptable physiology, seen not only in its antibiotic resistance and virulence phenotypes but also in its metabolic versatility. In this study, we observed that A. baumannii undergoes global transcriptional changes in response to human pleural fluid (PF), a key host-derived environmental signal. Differential gene expression analyses combined with experimental approaches revealed changes in A. baumannii metabolism, affecting cytotoxicity, persistence, bacterial killing, and chemotaxis. Over 1,220 genes representing 55% of the differentially expressed transcriptomic data corresponded to metabolic processes, including the upregulation of glutamate, short chain fatty acid, and styrene metabolism. We observed an upregulation by 1.83- and 2.61-fold of the pyruvate dehydrogenase complex subunits E3 and E2, respectively. We also found that pyruvate (PYR), in conjunction with PF, triggers an A. baumannii pathogenic behavior that adversely impacts human epithelial cell viability. Interestingly, PF also amplified A. baumannii cytotoxicity against murine macrophages, suggesting an immune evasion strategy implemented by A. baumannii. Moreover, we uncovered opposing metabolic strategies dependent on the degree of pathogenicity of the strains, where less pathogenic strains demonstrated greater utilization of PYR to promote persister formation in the presence of PF. Additionally, our transcriptomic analysis and growth studies of A. baumannii suggest the existence of an alternative phenylalanine (PA) catabolic route independent of the phenylacetic acid pathway, which converts PA to phenylpyruvate (PP) and shuttles intermediates into styrene metabolism. This alternative route promoted a neutrophil-evasive state, as PF-induced degradation of PP significantly reduced overall human neutrophil chemotaxis in ex vivo chemotactic assays. Taken together, these data highlight A. baumannii pathoadaptabililty in response to host signals and provide further insight into the role of bacterial metabolism in virulence traits, antibiotic persistence strategies, and host innate immune evasion.
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Affiliation(s)
- Nyah Rodman
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States
| | - Jasmine Martinez
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States
| | - Sammie Fung
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States
| | - Jun Nakanouchi
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States
| | - Amber L. Myers
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States
| | - Caitlin M. Harris
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States
| | - Emily Dang
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States
| | - Jennifer S. Fernandez
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States
| | - Christine Liu
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States
| | - Anthony M. Mendoza
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States
| | - Veronica Jimenez
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States
| | - Nikolas Nikolaidis
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States
| | - Catherine A. Brennan
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States
| | - Robert A. Bonomo
- Medical Service and Geriatrics Research, Education and Clinical Center (GRECC), Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH, United States
- Departments of Medicine, Pharmacology, Molecular Biology and Microbiology, Biochemistry, Proteomics and Bioinformatics, Case Western Reserve University School of Medicine, Cleveland, OH, United States
- CWRU-Cleveland VAMC Center for Antimicrobial Resistance and Epidemiology (Case VA CARES), Cleveland, OH, United States
| | - Rodrigo Sieira
- Fundacioìn Instituto Leloir-IIBBA CONICET, Buenos Aires, Argentina
| | - Maria Soledad Ramirez
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States
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Boluki E, Moradi M, Azar PS, Fekrazad R, Pourhajibagher M, Bahador A. The effect of antimicrobial photodynamic therapy against virulence genes expression in colistin-resistance Acinetobacter baumannii. Laser Ther 2019; 28:27-33. [PMID: 31190695 DOI: 10.5978/islsm.28_19-or-03] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Accepted: 10/31/2018] [Indexed: 11/06/2022]
Abstract
Background and Aims The emergence of drug-resistant infections is a global problem. Acinetobacter baumannii has attracted much attention over the last few years because of resistance to a wide range of antibiotics. Applying new non-antibiotic methods can save lives of many people around the world. Antimicrobial photodynamic therapy (aPDT) technique can be used as a new method for controlling the infections. In this study we investigated the effect of aPDT on the expression of pathogenic genes in colistin-resistance A. baumannii isolated from a burn patient. Materials and methods The suspension of colistin-resistance A. baumannii was incubated with 0.01 mg/ml of toluidine blue O (TBO) in the dark; then the light emitting diode device with a wavelength of 630 ± 10 nm and output intensity of 2000-4000 mW /cm2 was irradiated to the suspension at room temperature. Subsequently, after the aPDT, genes expression of ompA and pilZ was investigated by using real-time polymerase chain reaction technique. Result Among the genes studied, the transcript of the ompA gene after aPDT was increased significantly in comparison with control groups (P < 0.05). Whereas, there was no remarkable different in pilZ gene expression (P > 0.05). Conclusions It can be concluded from the results that the ompA as an outer membrane of A. baumannii is degraded after exposing aPDT and it will probably be done the penetration of antibiotics into cells of this bacterium easily.
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Affiliation(s)
- Ebrahim Boluki
- Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Moradi
- Department of Cell & Molecular Biology, Faculty of Biological Sciences, Kharazmi University, Tehran, Iran
| | | | - Reza Fekrazad
- Department of Periodontology, Dental Faculty - Laser research center in medical Sciences, AJA University of Medical Sciences, Tehran, Iran
| | - Maryam Pourhajibagher
- Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Abbas Bahador
- Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
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Contribution of Active Iron Uptake to Acinetobacter baumannii Pathogenicity. Infect Immun 2019; 87:IAI.00755-18. [PMID: 30718286 DOI: 10.1128/iai.00755-18] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 01/25/2019] [Indexed: 11/20/2022] Open
Abstract
Acinetobacter baumannii is an important nosocomial pathogen. Mechanisms that allow A. baumannii to cause human infection are still poorly understood. Iron is an essential nutrient for bacterial growth in vivo, and the multiplicity of iron uptake systems in A. baumannii suggests that iron acquisition contributes to the ability of A. baumannii to cause infection. In Gram-negative bacteria, active transport of ferrisiderophores and heme relies on the conserved TonB-ExbB-ExbD energy-transducing complex, while active uptake of ferrous iron is mediated by the Feo system. The A. baumannii genome invariably contains three tonB genes (tonB1, tonB2, and tonB3), whose role in iron uptake is poorly understood. Here, we generated A. baumannii mutants with knockout mutations in the feo and/or tonB gene. We report that tonB3 is essential for A. baumannii growth under iron-limiting conditions, whereas tonB1, tonB2, and feoB appear to be dispensable for ferric iron uptake. tonB3 deletion resulted in reduced intracellular iron content despite siderophore overproduction, supporting a key role of TonB3 in iron uptake. In contrast to the case for tonB1 and tonB2, the promoters of tonB3 and feo contain functional Fur boxes and are upregulated in iron-poor media. Both TonB3 and Feo systems are required for growth in complement-free human serum and contribute to resistance to the bactericidal activity of normal human serum, but only TonB3 appears to be essential for virulence in insect and mouse models of infection. Our findings highlight a central role of the TonB3 system for A. baumannii pathogenicity. Hence, TonB3 represents a promising target for novel antibacterial therapies and for the generation of attenuated vaccine strains.
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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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Palmer LD, Green ER, Sheldon JR, Skaar EP. Assessing Acinetobacter baumannii Virulence and Persistence in a Murine Model of Lung Infection. Methods Mol Biol 2019; 1946:289-305. [PMID: 30798564 PMCID: PMC6446551 DOI: 10.1007/978-1-4939-9118-1_26] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Acinetobacter baumannii is a Gram-negative opportunistic pathogen and a leading cause of ventilator-associated pneumonia. Murine models of A. baumannii lung infection allow researchers to experimentally assess A. baumannii virulence and host response. Intranasal administration of A. baumannii models acute lung infection. This chapter describes the methods to test A. baumannii virulence in a murine model of lung infection, including assessing the competitive index of a bacterial mutant and the associated inflammatory responses.
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Affiliation(s)
- Lauren D Palmer
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Erin R Green
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Jessica R Sheldon
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Eric P Skaar
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA.
- Vanderbilt Institute for Infection, Immunology and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA.
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Kröger C, MacKenzie KD, Alshabib EY, Kirzinger MWB, Suchan DM, Chao TC, Akulova V, Miranda-CasoLuengo AA, Monzon VA, Conway T, Sivasankaran SK, Hinton JCD, Hokamp K, Cameron ADS. The primary transcriptome, small RNAs and regulation of antimicrobial resistance in Acinetobacter baumannii ATCC 17978. Nucleic Acids Res 2018; 46:9684-9698. [PMID: 29986115 PMCID: PMC6182133 DOI: 10.1093/nar/gky603] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 06/21/2018] [Accepted: 06/26/2018] [Indexed: 12/12/2022] Open
Abstract
We present the first high-resolution determination of transcriptome architecture in the priority pathogen Acinetobacter baumannii. Pooled RNA from 16 laboratory conditions was used for differential RNA-seq (dRNA-seq) to identify 3731 transcriptional start sites (TSS) and 110 small RNAs, including the first identification in A. baumannii of sRNAs encoded at the 3' end of coding genes. Most sRNAs were conserved among sequenced A. baumannii genomes, but were only weakly conserved or absent in other Acinetobacter species. Single nucleotide mapping of TSS enabled prediction of -10 and -35 RNA polymerase binding sites and revealed an unprecedented base preference at position +2 that hints at an unrecognized transcriptional regulatory mechanism. To apply functional genomics to the problem of antimicrobial resistance, we dissected the transcriptional regulation of the drug efflux pump responsible for chloramphenicol resistance, craA. The two craA promoters were both down-regulated >1000-fold when cells were shifted to nutrient limited medium. This conditional down-regulation of craA expression renders cells sensitive to chloramphenicol, a highly effective antibiotic for the treatment of multidrug resistant infections. An online interface that facilitates open data access and visualization is provided as 'AcinetoCom' (http://bioinf.gen.tcd.ie/acinetocom/).
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Affiliation(s)
- Carsten Kröger
- Department of Microbiology, School of Genetics & Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, Dublin 2, Ireland
| | - Keith D MacKenzie
- Institute for Microbial Systems and Society, University of Regina, Regina, Saskatchewan S4S 0A2, Canada
- Department of Biology, University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - Ebtihal Y Alshabib
- Institute for Microbial Systems and Society, University of Regina, Regina, Saskatchewan S4S 0A2, Canada
- Department of Biology, University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - Morgan W B Kirzinger
- Institute for Microbial Systems and Society, University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - Danae M Suchan
- Institute for Microbial Systems and Society, University of Regina, Regina, Saskatchewan S4S 0A2, Canada
- Department of Biology, University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - Tzu-Chiao Chao
- Department of Biology, University of Regina, Regina, Saskatchewan S4S 0A2, Canada
- Institute of Environmental Change and Society, University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - Valentyna Akulova
- Institute for Microbial Systems and Society, University of Regina, Regina, Saskatchewan S4S 0A2, Canada
| | - Aleksandra A Miranda-CasoLuengo
- Department of Microbiology, School of Genetics & Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, Dublin 2, Ireland
| | - Vivian A Monzon
- Department of Microbiology, School of Genetics & Microbiology, Moyne Institute of Preventive Medicine, Trinity College Dublin, Dublin 2, Ireland
| | - Tyrrell Conway
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK 74078, USA
| | - Sathesh K Sivasankaran
- John P. Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Jay C D Hinton
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Karsten Hokamp
- Department of Genetics, School of Genetics & Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland
| | - Andrew D S Cameron
- Institute for Microbial Systems and Society, University of Regina, Regina, Saskatchewan S4S 0A2, Canada
- Department of Biology, University of Regina, Regina, Saskatchewan S4S 0A2, Canada
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Álvarez-Fraga L, Vázquez-Ucha JC, Martínez-Guitián M, Vallejo JA, Bou G, Beceiro A, Poza M. Pneumonia infection in mice reveals the involvement of the feoA gene in the pathogenesis of Acinetobacter baumannii. Virulence 2018; 9:496-509. [PMID: 29334313 PMCID: PMC5955439 DOI: 10.1080/21505594.2017.1420451] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Acinetobacter baumannii has emerged in the last decade as an important nosocomial pathogen. To identify genes involved in the course of a pneumonia infection, gene expression profiles were obtained from A. baumannii ATCC 17978 grown in mouse infected lungs and in culture medium. Gene expression analysis allowed us to determine a gene, the A1S_0242 gene (feoA), over-expressed during the pneumonia infection. In the present work, we evaluate the role of this gene, involved in iron uptake. The inactivation of the A1S_0242 gene resulted in an increase susceptibility to oxidative stress and a decrease in biofilm formation, in adherence to A549 cells and in fitness. In addition, infection of G. mellonella and pneumonia in mice showed that the virulence of the Δ0242 mutant was significantly attenuated. Data presented in this work indicated that the A1S_0242 gene from A. baumannii ATCC 17978 strain plays a role in fitness, adhesion, biofilm formation, growth, and, definitively, in virulence. Taken together, these observations show the implication of the feoA gene plays in the pathogenesis of A. baumannii and highlight its value as a potential therapeutic target.
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Affiliation(s)
- Laura Álvarez-Fraga
- a Servicio de Microbiología, Instituto de Investigación Biomédica (INIBIC), Complejo Hospitalario Universidade (CHUAC), Universidad da Coruña (UDC) , A Coruña , Spain
| | - Juan C Vázquez-Ucha
- a Servicio de Microbiología, Instituto de Investigación Biomédica (INIBIC), Complejo Hospitalario Universidade (CHUAC), Universidad da Coruña (UDC) , A Coruña , Spain
| | - Marta Martínez-Guitián
- a Servicio de Microbiología, Instituto de Investigación Biomédica (INIBIC), Complejo Hospitalario Universidade (CHUAC), Universidad da Coruña (UDC) , A Coruña , Spain
| | - Juan A Vallejo
- a Servicio de Microbiología, Instituto de Investigación Biomédica (INIBIC), Complejo Hospitalario Universidade (CHUAC), Universidad da Coruña (UDC) , A Coruña , Spain
| | - Germán Bou
- a Servicio de Microbiología, Instituto de Investigación Biomédica (INIBIC), Complejo Hospitalario Universidade (CHUAC), Universidad da Coruña (UDC) , A Coruña , Spain
| | - Alejandro Beceiro
- a Servicio de Microbiología, Instituto de Investigación Biomédica (INIBIC), Complejo Hospitalario Universidade (CHUAC), Universidad da Coruña (UDC) , A Coruña , Spain
| | - Margarita Poza
- a Servicio de Microbiología, Instituto de Investigación Biomédica (INIBIC), Complejo Hospitalario Universidade (CHUAC), Universidad da Coruña (UDC) , A Coruña , Spain
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Hijazi S, Visaggio D, Pirolo M, Frangipani E, Bernstein L, Visca P. Antimicrobial Activity of Gallium Compounds on ESKAPE Pathogens. Front Cell Infect Microbiol 2018; 8:316. [PMID: 30250828 PMCID: PMC6139391 DOI: 10.3389/fcimb.2018.00316] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 08/20/2018] [Indexed: 12/22/2022] Open
Abstract
ESKAPE bacteria are a major cause of multidrug-resistant infections, and new drugs are urgently needed to combat these pathogens. Given the importance of iron in bacterial physiology and pathogenicity, iron uptake and metabolism have become attractive targets for the development of new antibacterial drugs. In this scenario, the FDA-approved iron mimetic metal Gallium [Ga(III)] has been successfully repurposed as an antimicrobial drug. Ga(III) disrupts ferric iron-dependent metabolic pathways, thereby inhibiting microbial growth. This work provides the first comparative assessment of the antibacterial activity of Ga(NO3)3 (GaN), Ga(III)-maltolate (GaM), and Ga(III)-protoporphyrin IX (GaPPIX), belonging to the first-, second- and third-generation of Ga(III) formulations, respectively, on ESKAPE species, including reference strains and multidrug-resistant (MDR) clinical isolates. In addition to the standard culture medium Mueller Hinton broth (MHB), iron-depleted MHB (DMHB) and RPMI-1640 supplemented with 10% human serum (HS) (RPMI-HS) were also included in Ga(III)-susceptibility tests, because of their different nutrient and iron contents. All ESKAPE species were resistant to all Ga(III) compounds in MHB and DMHB (MIC > 32 μM), except Staphylococcus aureus and Acinetobacter baumannii, which were susceptible to GaPPIX. Conversely, the antibacterial activity of GaN and GaM was very evident in RPMI-HS, in which the low iron content and the presence of HS better mimic the in vivo environment. In RPMI-HS about 50% of the strains were sensitive (MIC < 32) to GaN and GaM, both compounds showing a similar spectrum of activity, although GaM was more effective than GaN. In contrast, GaPPIX lost its antibacterial activity in RPMI-HS likely due to the presence of albumin, which binds GaPPIX and counteracts its inhibitory effect. We also demonstrated that the presence of multiple heme-uptake systems strongly influences GaPPIX susceptibility in A. baumannii. Interestingly, GaN and GaM showed only a bacteriostatic effect, whereas GaPPIX exerted a bactericidal activity on susceptible strains. Altogether, our findings raise hope for the future development of Ga(III)-based compounds in the treatment of infections caused by multidrug-resistant ESKAPE pathogens.
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Affiliation(s)
- Sarah Hijazi
- Department of Science, Roma Tre University, Rome, Italy
| | | | - Mattia Pirolo
- Department of Science, Roma Tre University, Rome, Italy
| | | | | | - Paolo Visca
- Department of Science, Roma Tre University, Rome, Italy
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Abstract
Transition metals are required cofactors for many proteins that are critical for life, and their concentration within cells is carefully maintained to avoid both deficiency and toxicity. To defend against bacterial pathogens, vertebrate immune proteins sequester metals, in particular zinc, iron, and manganese, as a strategy to limit bacterial acquisition of these necessary nutrients in a process termed "nutritional immunity." In response, bacteria have evolved elegant strategies to access metals and counteract this host defense. In mammals, metal abundance can drastically shift due to changes in dietary intake or absorption from the intestinal tract, disrupting the balance between host and pathogen in the fight for metals and altering susceptibility to disease. This review describes the current understanding of how dietary metals modulate host-microbe interactions and the subsequent impact on the outcome of disease.
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Affiliation(s)
- Christopher A Lopez
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Eric P Skaar
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, USA; Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN, USA.
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Kamoshida G, Kikuchi-Ueda T, Nishida S, Tansho-Nagakawa S, Ubagai T, Ono Y. Pathogenic Bacterium Acinetobacter baumannii Inhibits the Formation of Neutrophil Extracellular Traps by Suppressing Neutrophil Adhesion. Front Immunol 2018; 9:178. [PMID: 29467765 PMCID: PMC5808340 DOI: 10.3389/fimmu.2018.00178] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 01/19/2018] [Indexed: 12/12/2022] Open
Abstract
Hospital-acquired infections caused by Acinetobacter baumannii have become problematic because of high rates of drug resistance. A. baumannii is usually harmless, but it may cause infectious diseases in an immunocompromised host. Although neutrophils are the key players of the initial immune response against bacterial infection, their interactions with A. baumannii remain largely unknown. A new biological defense mechanism, termed neutrophil extracellular traps (NETs), has been attracting attention. NETs play a critical role in bacterial killing by bacterial trapping and inactivation. Many pathogenic bacteria have been reported to induce NET formation, while an inhibitory effect on NET formation is rarely reported. In the present study, to assess the inhibition of NET formation by A. baumannii, bacteria and human neutrophils were cocultured in the presence of phorbol 12-myristate 13-acetate (PMA), and NET formation was evaluated. NETs were rarely observed during the coculture despite neutrophil PMA stimulation. Furthermore, A. baumannii prolonged the lifespan of neutrophils by inhibiting NET formation. The inhibition of NET formation by other bacteria was also investigated. The inhibitory effect was only apparent with live A. baumannii cells. Finally, to elucidate the mechanism of this inhibition, neutrophil adhesion was examined. A. baumannii suppressed the adhesion ability of neutrophils, thereby inhibiting PMA-induced NET formation. This suppression of cell adhesion was partly due to suppression of the surface expression of CD11a in neutrophils. The current study constitutes the first report on the inhibition of NET formation by a pathogenic bacterium, A. baumannii, and prolonging the neutrophil lifespan. This novel pathogenicity to inhibit NET formation, thereby escaping host immune responses might contribute to a development of new treatment strategies for A. baumannii infections.
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Affiliation(s)
- Go Kamoshida
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Takane Kikuchi-Ueda
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Satoshi Nishida
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Shigeru Tansho-Nagakawa
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Tsuneyuki Ubagai
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Yasuo Ono
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
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45
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Bohac TJ, Shapiro JA, Wencewicz TA. Rigid Oxazole Acinetobactin Analog Blocks Siderophore Cycling in Acinetobacter baumannii. ACS Infect Dis 2017; 3:802-806. [PMID: 28991447 DOI: 10.1021/acsinfecdis.7b00146] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The emergence of multidrug resistant (MDR) Gram-negative bacterial pathogens has raised global concern. Nontraditional therapeutic strategies, including antivirulence approaches, are gaining traction as a means of applying less selective pressure for resistance in vivo. Here, we show that rigidifying the structure of the siderophore preacinetobactin from MDR Acinetobacter baumannii via oxidation of the phenolate-oxazoline moiety to a phenolate-oxazole results in a potent inhibitor of siderophore transport and imparts a bacteriostatic effect at low micromolar concentrations under infection-like conditions.
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Affiliation(s)
- Tabbetha J. Bohac
- Department of Chemistry, Washington University in St. Louis, One Brookings Drive, St. Louis, Missouri 63130, United States
| | - Justin A. Shapiro
- Department of Chemistry, Washington University in St. Louis, One Brookings Drive, St. Louis, Missouri 63130, United States
| | - Timothy A. Wencewicz
- Department of Chemistry, Washington University in St. Louis, One Brookings Drive, St. Louis, Missouri 63130, United States
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46
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Combating virulence of Gram-negative bacilli by OmpA inhibition. Sci Rep 2017; 7:14683. [PMID: 29089624 PMCID: PMC5666006 DOI: 10.1038/s41598-017-14972-y] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 10/19/2017] [Indexed: 12/23/2022] Open
Abstract
Preventing the adhesion of pathogens to host cells provides an innovative approach to tackling multidrug-resistant bacteria. In this regard, the identification of outer membrane protein A (OmpA) as a key bacterial virulence factor has been a major breakthrough. The use of virtual screening helped us to identify a cyclic hexapeptide AOA-2 that inhibits the adhesion of Acinetobacter baumannii, Pseudomonas aeruginosa and Escherichia coli to host cells and the formation of biofilm, thereby preventing the development of infection in vitro and in a murine sepsis peritoneal model. Inhibition of OmpA offers a strategy as monotherapy to address the urgent need for treatments for infections caused by Gram-negative bacilli.
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Ambrosi C, Scribano D, Aleandri M, Zagaglia C, Di Francesco L, Putignani L, Palamara AT. Acinetobacter baumannii Virulence Traits: A Comparative Study of a Novel Sequence Type with Other Italian Endemic International Clones. Front Microbiol 2017; 8:1977. [PMID: 29075243 PMCID: PMC5643476 DOI: 10.3389/fmicb.2017.01977] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 09/25/2017] [Indexed: 01/20/2023] Open
Abstract
Carbapenem-resistant Acinetobacter baumannii (CRAb) have emerged in recent decades as major causes of nosocomial infections. Resistance is mainly due to overexpression of intrinsic and/or acquired carbapenemases, especially oxacillinases (OXA). In Italy, although the sequence type (ST) 2 and the ST78 are the most frequently detected, we recently reported ST632, a single locus variant of ST2. Therefore, this study was aimed at unraveling common bacterial surface virulence factors involved in pathogenesis and antibiotic resistance in representative CRAb of these ST genotypes. Outer membrane protein (OMP) composition together with motility, biofilm formation, in vitro adherence to, invasion of, and survival within pneumocytes were analyzed. Differently from the carbapenem-susceptible reference strain ATCC 17978, either overexpressed OXA-51 or both OXA-23 and OXA-51 co-purified with OMPs in CRAb. This tight association ensures their maximal concentration on the inner surface of the outer membrane to provide the best protection against carbapenems. These findings led us to propose for the first time a common behavior of OXA enzymes in CRAb. Despite the presence of both OmpA and phosphorylcholine-porinD and the ability of all the strains to adhere to cells, invasion, and survival within pneumocytes was shown only by ST2 and ST78 isolates, sharing the highest number of identified OMPs. Conversely, notwithstanding genetic and OMPs similarities with ST2, ST632 was unable to invade and survive within epithelial cells. Overall, our study shows that different STs share a specific OMP composition, also shaped by overexpressed OXA, that is needed for invasiveness and survival of CRAb.
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Affiliation(s)
- Cecilia Ambrosi
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy.,Dani Di Giò Foundation-Onlus, Rome, Italy
| | - Daniela Scribano
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy.,Department of Medical, Oral and Biotechnological Sciences, Università degli Studi "G. d'Annunzio" Chieti-Pescara, Chieti, Italy
| | - Marta Aleandri
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - Carlo Zagaglia
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Rome, Italy
| | - Laura Di Francesco
- Unit of Human Microbiome, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Lorenza Putignani
- Unit of Human Microbiome, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.,Unit of Parasitology, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Anna Teresa Palamara
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Laboratory Affiliated to Institute Pasteur Italia, Cenci-Bolognetti Foundation, Rome, Italy.,San Raffaele Pisana, IRCCS, Telematic University, Rome, Italy
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48
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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: 642] [Impact Index Per Article: 91.7] [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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49
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Repizo GD, Viale AM, Borges V, Cameranesi MM, Taib N, Espariz M, Brochier-Armanet C, Gomes JP, Salcedo SP. The Environmental Acinetobacter baumannii Isolate DSM30011 Reveals Clues into the Preantibiotic Era Genome Diversity, Virulence Potential, and Niche Range of a Predominant Nosocomial Pathogen. Genome Biol Evol 2017; 9:2292-2307. [PMID: 28934377 PMCID: PMC5604120 DOI: 10.1093/gbe/evx162] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/24/2017] [Indexed: 12/20/2022] Open
Abstract
Acinetobacter baumannii represents nowadays an important nosocomial opportunistic pathogen whose reservoirs outside the clinical setting are obscure. Here, we traced the origins of the collection strain A. baumannii DSM30011 to an isolate first reported in 1944, obtained from the enriched microbiota responsible of the aerobic decomposition of the resinous desert shrub guayule. Whole-genome sequencing and phylogenetic analysis based on core genes confirmed DSM30011 affiliation to A. baumannii. Comparative studies with 32 complete A. baumannii genomes revealed the presence of 12 unique accessory chromosomal regions in DSM30011 including five encompassing phage-related genes, five containing toxin genes of the type-6 secretion system, and one with an atypical CRISPRs/cas cluster. No antimicrobial resistance islands were identified in DSM30011 agreeing with a general antimicrobial susceptibility phenotype including folate synthesis inhibitors. The marginal ampicillin resistance of DSM30011 most likely derived from chromosomal ADC-type ampC and blaOXA-51-type genes. Searching for catabolic pathways genes revealed several clusters involved in the degradation of plant defenses including woody tissues and a previously unreported atu locus responsible of aliphatic terpenes degradation, thus suggesting that resinous plants may provide an effective niche for this organism. DSM30011 also harbored most genes and regulatory mechanisms linked to persistence and virulence in pathogenic Acinetobacter species. This strain thus revealed important clues into the genomic diversity, virulence potential, and niche ranges of the preantibiotic era A. baumannii population, and may provide an useful tool for our understanding of the processes that led to the recent evolution of this species toward an opportunistic pathogen of humans.
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Affiliation(s)
- Guillermo D. Repizo
- Laboratory of Molecular Microbiology and Structural Biochemistry, CNRS UMR5086, University of Lyon, France
- Departamento de Microbiologia, Instituto de Biologia Molecular y Celular de Rosario (IBR, CONICET), Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, Argentina
| | - Alejandro M. Viale
- Departamento de Microbiologia, Instituto de Biologia Molecular y Celular de Rosario (IBR, CONICET), Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, Argentina
| | - Vítor Borges
- Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health, Lisbon, Portugal
| | - María M. Cameranesi
- Departamento de Microbiologia, Instituto de Biologia Molecular y Celular de Rosario (IBR, CONICET), Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, Argentina
| | - Najwa Taib
- Laboratoire de Biométrie et Biologie Évolutive, Univ. Lyon, Université Lyon 1, CNRS, UMR5558, Villeurbanne, France
| | - Martín Espariz
- Departamento de Microbiologia, Instituto de Biologia Molecular y Celular de Rosario (IBR, CONICET), Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, Argentina
| | - Céline Brochier-Armanet
- Laboratoire de Biométrie et Biologie Évolutive, Univ. Lyon, Université Lyon 1, CNRS, UMR5558, Villeurbanne, France
| | - João Paulo Gomes
- Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health, Lisbon, Portugal
| | - Suzana P. Salcedo
- Laboratory of Molecular Microbiology and Structural Biochemistry, CNRS UMR5086, University of Lyon, France
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50
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Muzaheed, Alzahrani FM, Sattar Shaikh S. Acinetobacter baumannii Infection in Transfusion Dependent Thalassemia Patients with Sepsis. BIOMED RESEARCH INTERNATIONAL 2017; 2017:2351037. [PMID: 28596960 PMCID: PMC5450173 DOI: 10.1155/2017/2351037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 04/27/2017] [Accepted: 04/30/2017] [Indexed: 01/19/2023]
Abstract
PURPOSE To identify the Acinetobacter baumannii infection among transfusion dependent thalassemia patients. METHODS A quantitative approach was employed to assess Acinetobacter baumannii infection in transfusion dependent thalassemia patients. Samples were collected from 916 patients, which have shown bacterial growth on MacConkey and blood agar culture media. A. baumannii strains were identified by microbiological methods and Gram's staining. API 20 E kit (Biomerieux, USA) was used for final identification. RESULTS From 916 cultured blood specimens, 107 (11.6%) showed growth of A. baumannii. Serum ferritin in thalassemic patients without bacterial infections was 3849.5 ± 1513.5 µg/L versus 6413.5 ± 2103.9 µg/L in those with bacterial infections (p = 0.0001). Acinetobacter baumannii infected patients have shown higher serum ferritin levels (p = 0.0001). Serum ferritin in thalassemic patients was 3849.5 ± 1513.5 µg/L versus 6413.5 ± 2103.9 µg/L in those with bacterial infections (p = 0.0001). Acinetobacter baumannii infected patients showed high serum ferritin levels (p = 0.0001). The clinical symptoms have been found with A. baumannii +ve with a mean and standard deviation of 47 (5.1%) and A. baumannii -ve with mean and standard deviation of 60 (6.5%). CONCLUSION Isolation of asymptomatic A. baumannii from the thalassemia patients shows an alarming situation of bacterial infections. A continuous surveillance of transfusion dependent thalassemia patients is recommended for bacterial sepsis.
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Affiliation(s)
- Muzaheed
- Department of Clinical Laboratory Science, College of Applied Medical Sciences, University of Dammam, Dammam, Saudi Arabia
| | - Faisal Mousa Alzahrani
- Department of Clinical Laboratory Science, College of Applied Medical Sciences, University of Dammam, Dammam, Saudi Arabia
| | - Saeed Sattar Shaikh
- Department of Clinical Laboratory Science, College of Applied Medical Sciences, University of Dammam, Dammam, Saudi Arabia
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