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Sun Y, Wang L, Zhang M, Jie J, Guan Q, Fu J, Chu X, Chen D, Li C, Song L, Luo ZQ. Acinetobacter nosocomialis utilizes a unique type VI secretion system to promote its survival in niches with prey bacteria. mBio 2024; 15:e0146824. [PMID: 38916378 PMCID: PMC11253628 DOI: 10.1128/mbio.01468-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2024] [Accepted: 06/10/2024] [Indexed: 06/26/2024] Open
Abstract
Pathogenic bacteria of the Acinetobacter genus pose a severe threat to human health worldwide due to their strong adaptability, tolerance, and antibiotic resistance. Most isolates of these bacteria harbor a type VI secretion system (T6SS) that allows them to outcompete co-residing microorganisms, but whether this system is involved in acquiring nutrients from preys remains less studied. In this study, we found that Ab25, a clinical isolate of Acinetobacter nosocomialis, utilizes a T6SS to kill taxonomically diverse microorganisms, including bacteria and fungi. The T6SS of Ab25 is constitutively expressed, and among the three predicted effectors, T6e1, a member of the RHS effector family, contributes the most for its antimicrobial activity. T6e1 undergoes self-cleavage, and a short carboxyl fragment with nuclease activity is sufficient to kill target cells via T6SS injection. Interestingly, strain Ab25 encodes an orphan VgrG protein, which when overexpressed blocks the firing of its T6SS. In niches such as dry plastic surfaces, the T6SS promotes prey microorganism-dependent survival of Ab25. These results reveal that A. nosocomialis employs T6SSs that are highly diverse in their regulation and effector composition to gain a competitive advantage in environments with scarce nutrient supply and competing microbes.IMPORTANCEThe type VI secretion system (T6SS) plays an important role in bacterial adaptation to environmental challenges. Members of the Acinetobacter genus, particularly A. baumannii and A. nosocomialis, are notorious for their multidrug resistance and their ability to survive in harsh environments. In contrast to A. baumannii, whose T6SS has been well-studied, few research works have focused on A. nosocomialis. In this study, we found that an A. nosocomialis strain utilizes a contitutively active T6SS to kill diverse microorganisms, including bacteria and fungi. Although T6SS structural proteins of A. nosocomialis are similar to those of A. baumannii, the effector repertoire differs greatly. Interestingly, the T6SS of the A. nosocomialis strain codes for an ophan VgrG protein, which blocks the firing of the system when overexpressed, suggesting the existence of a new regulatory mechanism for the T6SS. Importantly, although the T6SS does not provide an advantage when the bacterium is grown in nutrient-rich medium, it allows A. nosocomialis to survive better in dry surfaces that contain co-existing bacteria. Our results suggest that killing of co-residing microorganisms may increase the effectiveness of strategies designed to reduce the fitness of Acinetobacter bacteria by targeting their T6SS.
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Affiliation(s)
- Yu Sun
- Department of Respiratory Medicine, Center of Infectious Diseases and Pathogen Biology, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, The First Hospital of Jilin University, Changchun, China
- Department of Gastroenterology, Endoscopy center, The First Hospital of Jilin University, Changchun, China
| | - Lidong Wang
- Department of Respiratory Medicine, Center of Infectious Diseases and Pathogen Biology, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, The First Hospital of Jilin University, Changchun, China
| | - Ming Zhang
- Department of Ultrasound, The First Hospital of Jilin University, Changchun, China
| | - Jing Jie
- Department of Respiratory Medicine, Center of Infectious Diseases and Pathogen Biology, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, The First Hospital of Jilin University, Changchun, China
| | - Qingtian Guan
- Bioinformatics Laboratory, The First Hospital of Jilin University, Changchun, China
| | - Jiaqi Fu
- Department of Respiratory Medicine, Center of Infectious Diseases and Pathogen Biology, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, The First Hospital of Jilin University, Changchun, China
| | - Xiao Chu
- Department of Respiratory Medicine, Center of Infectious Diseases and Pathogen Biology, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, The First Hospital of Jilin University, Changchun, China
| | - Dong Chen
- Department of Respiratory Medicine, Center of Infectious Diseases and Pathogen Biology, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, The First Hospital of Jilin University, Changchun, China
| | - Chunxiuli Li
- Department of Respiratory Medicine, Center of Infectious Diseases and Pathogen Biology, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, The First Hospital of Jilin University, Changchun, China
| | - Lei Song
- Department of Respiratory Medicine, Center of Infectious Diseases and Pathogen Biology, Key Laboratory of Organ Regeneration and Transplantation of the Ministry of Education, State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Diseases, The First Hospital of Jilin University, Changchun, China
| | - Zhao-Qing Luo
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, USA
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Jia WL, Zhang M, Gao FZ, Bai H, He LX, He LY, Liu T, Han Y, Ying GG. Antibiotic resistome in landfill leachate and impact on groundwater. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 927:171991. [PMID: 38547976 DOI: 10.1016/j.scitotenv.2024.171991] [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: 01/17/2024] [Revised: 03/14/2024] [Accepted: 03/24/2024] [Indexed: 04/08/2024]
Abstract
Landfill leachate is a hotspot in antibiotic resistance development. However, little is known about antibiotic resistome and host pathogens in leachate and their effects on surrounding groundwater. Here, metagenomic sequencing was used to explore profiles, host bacteria, environmental risks and influencing factors of antibiotic resistome in raw and treated leachate and surrounding groundwater of three landfills. Results showed detection of a total of 324 antibiotic resistance genes (ARGs). The ARGs conferring resistance to multidrug (8.8 %-25.7 %), aminoglycoside (13.1 %-39.2 %), sulfonamide (10.0 %-20.9 %), tetracycline (5.7 %-34.4 %) and macrolide-lincosamide-streptogramin (MLS, 5.3 %-29.5 %) were dominant in raw leachate, while multidrug resistance genes were the major ARGs in treated leachate (64.1 %-83.0 %) and groundwater (28.7 %-76.6 %). Source tracking analysis suggests non-negligible influence of leachate on the ARGs in groundwater. The pathogens including Acinetobacter pittii, Pseudomonas stutzeri and P. alcaligenes were the major ARG-carrying hosts. Variance partitioning analysis indicates that the microbial community, abiotic variables and their interaction contributed most to the antibiotic resistance development. Our results shed light on the dissemination and driving mechanisms of ARGs from leachate to the groundwater, indicating that a comprehensive risk assessment and efficient treatment approaches are needed to deal with ARGs in landfill leachate and nearby groundwater. ENVIRONMENTAL IMPLICATIONS: Antibiotic resistance genes are found abundant in the landfill sites, and these genes could be disseminated into groundwater via leaching of wastewater and infiltration of leachate. This results in deterioration of groundwater quality and human health risks posed by these ARGs and related pathogens. Thus measures should be taken to minimize potential negative impacts of landfills on the surrounding environment.
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Affiliation(s)
- Wei-Li Jia
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China; School of Environment, South China Normal University, University Town, Guangzhou 510006, China
| | - Min Zhang
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China; School of Environment, South China Normal University, University Town, Guangzhou 510006, China; Pearl River Water Resources Research Institute, Pearl River Water Resources Commission of the Ministry of Water Resources, Guangzhou, China
| | - Fang-Zhou Gao
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China; School of Environment, South China Normal University, University Town, Guangzhou 510006, China
| | - Hong Bai
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China; School of Environment, South China Normal University, University Town, Guangzhou 510006, China
| | - Lu-Xi He
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China; School of Environment, South China Normal University, University Town, Guangzhou 510006, China
| | - Liang-Ying He
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China; School of Environment, South China Normal University, University Town, Guangzhou 510006, China
| | - Ting Liu
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China; School of Environment, South China Normal University, University Town, Guangzhou 510006, China
| | - Yu Han
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China; School of Environment, South China Normal University, University Town, Guangzhou 510006, China
| | - Guang-Guo Ying
- SCNU Environmental Research Institute, Guangdong Provincial Key Laboratory of Chemical Pollution and Environmental Safety & MOE Key Laboratory of Theoretical Chemistry of Environment, South China Normal University, Guangzhou 510006, China; School of Environment, South China Normal University, University Town, Guangzhou 510006, China.
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He X, He J, Tang J, Huang X, Yu Y, Hua X. Genetic characterization of plasmid-borne bla OXA-58 and bla OXA-72 in Acinetobacter pittii in Shaanxi, China. J Glob Antimicrob Resist 2024; 38:167-172. [PMID: 38768708 DOI: 10.1016/j.jgar.2024.05.007] [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: 12/14/2023] [Revised: 05/07/2024] [Accepted: 05/09/2024] [Indexed: 05/22/2024] Open
Abstract
OBJECTIVES Acinetobacter pittii has emerged as an opportunistic nosocomial pathogen associated with hospital-acquired infections. The purpose of this study was to investigate the genetic structures of plasmids carrying carbapenemase genes blaOXA-58 and blaOXA-72 in A. pittii strains AR3676 and AR3651 isolated from patients. METHODS Antimicrobial susceptibility testing was performed using broth microdilution. Whole-genome sequencing and bioinformatics analysis were performed to characterize the genome of A. pittii AR3676 and AR3651. Conjugation experiments were conducted to evaluate plasmid transferability. Phylogenetic and comparative genomic analysis were performed to explore the characteristics of carbapenem-resistant A. pittii isolates worldwide. RESULTS The AR3676 strain showed resistance to imipenem. The 19 700-bp plasmid pAR3676-OXA-58 harboured blaOXA-58 with genetic contexts consisting of a truncated ISAba3-like-blaOXA58-ISAba3. Additionally, the AR3651 strain showed resistance to imipenem and meropenem. The AR3651 genome comprised one 9,837-bp RepA_AB plasmid pAR3651-OXA-72 harbouring blaOXA-72. This blaOXA-72 was flanked by XerC/XerD recombination sites. The conjugation of plasmids pAR3676-OXA-58 and pAR3651-OXA-72 from A. pittii to Acinetobacter baumannii ATCC 17978RIFR failed three independent times. Phylogenetic analysis of A. pittii strains AR3676, AR3651, and a further 504 A. pittii strains collected between 1966 and 2022 from various geographic localities revealed genetic diversity with a heterogeneous distribution of carbapenemase genes. CONCLUSIONS A. pittii strains with a plasmid carrying blaOXA-58 or blaOXA-72 may serve as an important reservoir of carbapenemase genes. Carbapenemase genes on a single plasmid may facilitate their dissemination and persistence. Additionally, pdif sites and mobile elements play an important role in the mobilization of resistance genes and plasmid evolution.
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Affiliation(s)
- Xiaoliang He
- Department of Clinical Laboratory, Hanzhong Central Hospital, Hanzhong, People's Republic of China; Department of Infectious Diseases, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China; Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, People's Republic of China; Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Jintao He
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China; Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, People's Republic of China; Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Jin Tang
- Department of Clinical Laboratory, Hanzhong Central Hospital, Hanzhong, People's Republic of China
| | - Xiaoxia Huang
- Department of Clinical Laboratory, Hanzhong Central Hospital, Hanzhong, People's Republic of China
| | - Yunsong Yu
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China; Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, People's Republic of China; Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China
| | - Xiaoting Hua
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China; Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, People's Republic of China; Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, People's Republic of China.
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Pekkle Lam HY, Lai MJ, Wu WJ, Chin YH, Chao HJ, Chen LK, Peng SY, Chang KC. Isolation and characterization of bacteriophages with activities against multi-drug-resistant Acinetobacter nosocomialis causing bloodstream infection in vivo. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2023; 56:1026-1035. [PMID: 37586915 DOI: 10.1016/j.jmii.2023.07.012] [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: 02/23/2023] [Revised: 07/04/2023] [Accepted: 07/31/2023] [Indexed: 08/18/2023]
Abstract
BACKGROUND Acinetobacter nosocomialis (A. nosocomialis) is a glucose non-fermentative, gram-negative bacillus that belongs to the Acinetobacter calcoaceticus-baumannii complex. In recent years, studies have found an increased clinical prevalence of A. nosocomialis. However, given the increasing trend of antibiotic resistance, developing new antibacterial agents is vital. Currently, research regarding bacteriophage therapy against A. nosocomialis is only limited. METHODS Two A. nosocomialis bacteriophages, TCUAN1 and TCUAN2, were isolated from sewage. Experiments such as transmission electron microscopy (TEM), host-range analysis, and sequencing were performed to determine their biological and genomic characteristics. TCUAN2 were further subjected to in vivo experiments and their derived-endolysin were cloned and tested against their bacteria host. RESULTS Transmission electron microscopy revealed that TCUAN1 and TCUAN2 belong to Myoviridae and Podoviridae, respectively. Both phages show a broad host spectrum and rapid adsorption efficiency. Further biological analysis showed that TCUAN2 possesses a shorter latent period and larger burst size compared to TCUAN1. Because TCUAN2 showed a better antibacterial activity, it was injected into A. nosocomialis-infected mice which resulted in a significant decrease in bacterial load levels in the blood and increased the mice's survival. Finally, genomic analysis revealed that the complete nucleotide sequence of TCUAN1 is 49, 691 bps (containing 75 open reading frames) with a G + C content of 39.3%; whereas the complete nucleotide sequence of TCUAN2 is 41, 815 bps (containing 68 open reading frames) with a G + C content of 39.1%. The endolysin gene cloned and purified from TCUAN2 also showed antibacterial activity when used with a chelator EDTA.
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Affiliation(s)
- Ho Yin Pekkle Lam
- Department of Biochemistry, School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Meng-Jiun Lai
- Department of Laboratory Medicine and Biotechnology, Tzu Chi University, Hualien, Taiwan
| | - Wen-Jui Wu
- Department of Laboratory Medicine and Biotechnology, Tzu Chi University, Hualien, Taiwan
| | - Ying-Hao Chin
- Department of Laboratory Medicine, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan
| | - Huei-Jen Chao
- Department of Laboratory Medicine, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan
| | - Li-Kuang Chen
- Department of Laboratory Medicine, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan
| | - Shih-Yi Peng
- Department of Biochemistry, School of Medicine, Tzu Chi University, Hualien, Taiwan.
| | - Kai-Chih Chang
- Department of Laboratory Medicine and Biotechnology, Tzu Chi University, Hualien, Taiwan; Department of Laboratory Medicine, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan.
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Ordoni R, Amini Y, Ranayi MA, Avestan Z, Mohagheghi-Fard AH, Zandhaghighi M, Bameri Z, Kord E, Shahraki-Zahedani S, Dehvari A. Prevalence of the per, tem, veb, shv genes in Acinetobacter baumannii Isolated from Educational Hospital of Zahedan, Iran. IRANIAN JOURNAL OF MEDICAL MICROBIOLOGY 2022. [DOI: 10.30699/ijmm.16.6.566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Lynch JP, Clark NM, Zhanel GG. Infections Due to Acinetobacter baumannii-calcoaceticus Complex: Escalation of Antimicrobial Resistance and Evolving Treatment Options. Semin Respir Crit Care Med 2022; 43:97-124. [PMID: 35172361 DOI: 10.1055/s-0041-1741019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Bacteria within the genus Acinetobacter (principally A. baumannii-calcoaceticus complex [ABC]) are gram-negative coccobacilli that most often cause infections in nosocomial settings. Community-acquired infections are rare, but may occur in patients with comorbidities, advanced age, diabetes mellitus, chronic lung or renal disease, malignancy, or impaired immunity. Most common sites of infections include blood stream, skin/soft-tissue/surgical wounds, ventilator-associated pneumonia, orthopaedic or neurosurgical procedures, and urinary tract. Acinetobacter species are intrinsically resistant to multiple antimicrobials, and have a remarkable ability to acquire new resistance determinants via plasmids, transposons, integrons, and resistance islands. Since the 1990s, antimicrobial resistance (AMR) has escalated dramatically among ABC. Global spread of multidrug-resistant (MDR)-ABC strains reflects dissemination of a few clones between hospitals, geographic regions, and continents; excessive antibiotic use amplifies this spread. Many isolates are resistant to all antimicrobials except colistimethate sodium and tetracyclines (minocycline or tigecycline); some infections are untreatable with existing antimicrobial agents. AMR poses a serious threat to effectively treat or prevent ABC infections. Strategies to curtail environmental colonization with MDR-ABC require aggressive infection-control efforts and cohorting of infected patients. Thoughtful antibiotic strategies are essential to limit the spread of MDR-ABC. Optimal therapy will likely require combination antimicrobial therapy with existing antibiotics as well as development of novel antibiotic classes.
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Affiliation(s)
- Joseph P Lynch
- Division of Pulmonary, Critical Care Medicine, Allergy, and Clinical Immunology; Department of Medicine; The David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Nina M Clark
- Division of Infectious Diseases, Department of Medicine, Loyola University Medical Center, Maywood, Illinois
| | - George G Zhanel
- Department of Medical Microbiology/Infectious Diseases, University of Manitoba, Max Rady College of Medicine, Winnipeg, Manitoba, Canada
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Sharma A, Gaind R. Development of Loop-Mediated Isothermal Amplification Assay for Detection of Clinically Significant Members of Acinetobacter calcoaceticus-baumannii Complex and Associated Carbapenem Resistance. Front Mol Biosci 2021; 8:659256. [PMID: 34250011 PMCID: PMC8260673 DOI: 10.3389/fmolb.2021.659256] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 05/31/2021] [Indexed: 11/13/2022] Open
Abstract
Background:Acinetobacter calcoaceticus–baumannii (ACB) complex has emerged as an important nosocomial pathogen and is associated with life-threatening infections, especially among ICU patients, including neonates. Carbapenem resistance in Acinetobacter baumannii has emerged globally and is commonly mediated by blaOXA-23. Clinically significant infections with carbapenem-resistant Acinetobacter baumannii (CRAB) are a major concern since therapeutic options are limited and associated mortality is high. Early diagnosis of both the pathogen and resistance is important to initiate the optimal therapy and prevent selection of resistance. In the current study, a loop-mediated isothermal amplification (LAMP) assay was developed for rapid detection of the ACB complex and carbapenem resistance mediated by blaOXA-23. Methodology: Universal LAMP primers were designed for the detection of significant members of the ACB complex and carbapenem resistance targeting the ITS 16S–23S rRNA and blaOXA-23 gene respectively. The optimal conditions for the LAMP assay were standardized for each primer set using standard ATCC strains. The sensitivity of the LAMP assay was assessed based on the limit of detection (LOD) using different DNA concentrations and colony counts. The specificity of LAMP was determined using the non-ACB complex and non-Acinetobacter species. The results of the LAMP assay were compared with those of polymerase chain reaction (PCR). Results: The optimal temperature for the LAMP assay was 65°C, and the detection time varied with various primers designed. Using the ITS Ab1 primer, LODs of LAMP and PCR assays were 100 pg/μl and 1 ng/μl of DNA concentration and 104 cfu/ml and 108 cfu/ml of colony count, respectively. The LAMP assay was 10- and 104-fold more sensitive than PCR using DNA concentration and colony count, respectively. The LAMP assay was found to be specific for clinically important ACB complex species. Significance of the study: The LAMP assay can be applied for early detection of significant species of the ACB complex from clinical samples and their carbapenem-resistant variants. Depending on the emerging pathogen and locally prevalent resistance genes, the LAMP assay can be modified for detection of colonization or infection by various resistant bugs.
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Affiliation(s)
- Amit Sharma
- Department of Microbiology, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi, India.,University School of Medicine and Paramedical Health Sciences, Guru Gobind Singh Indraprastha University, Dwarka, India
| | - Rajni Gaind
- Department of Microbiology, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi, India
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Genomic Characterization of Clinical Extensively Drug-Resistant Acinetobacter pittii Isolates. Microorganisms 2021; 9:microorganisms9020242. [PMID: 33503968 PMCID: PMC7912037 DOI: 10.3390/microorganisms9020242] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 01/20/2021] [Accepted: 01/20/2021] [Indexed: 01/26/2023] Open
Abstract
Carbapenem-resistant Acinetobacter pittii (CRAP) is a causative agent of nosocomial infections. This study aimed to characterize clinical isolates of CRAP from a tertiary hospital in Northeast Thailand. Six isolates were confirmed as extensively drug-resistant Acinetobacter pittii (XDRAP). The blaNDM-1 gene was detected in three isolates, whereas blaIMP-14 and blaIMP-1 were detected in the others. Multilocus sequence typing with the Pasteur scheme revealed ST220 in two isolates, ST744 in two isolates, and ST63 and ST396 for the remaining two isolates, respectively. Genomic characterization revealed that six XDRAP genes contained antimicrobial resistance genes: ST63 (A436) and ST396 (A1) contained 10 antimicrobial resistance genes, ST220 (A984 and A864) and ST744 (A56 and A273) contained 9 and 8 antimicrobial resistance genes, respectively. The single nucleotide polymorphism (SNP) phylogenetic tree revealed that the isolates A984 and A864 were closely related to A. pittii YB-45 (ST220) from China, while A436 was related to A. pittii WCHAP100020, also from China. A273 and A56 isolates (ST744) were clustered together; these isolates were closely related to strains 2014S07-126, AP43, and WCHAP005069, which were isolated from Taiwan and China. Strict implementation of infection control based upon the framework of epidemiological analyses is essential to prevent outbreaks and contain the spread of the pathogen. Continued surveillance and close monitoring with molecular epidemiological tools are needed.
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Kaur R, Singh D, Kesavan AK, Kaur R. Molecular characterization and antimicrobial susceptibility of bacterial isolates present in tap water of public toilets. Int Health 2020; 12:472-483. [PMID: 31693132 PMCID: PMC7443727 DOI: 10.1093/inthealth/ihz074] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Revised: 06/14/2019] [Accepted: 06/17/2019] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The present study was carried out to investigate the tap water quality of public toilets in Amritsar, Punjab, India. METHODS Water samples from the taps of the public toilets were collected in sterile containers and physicochemical and bacteriological analysis was performed using standard methods. Also, genotypic and phenotypic characterization of the bacterial isolates was performed using different biochemical tests and 16S ribosomal RNA analysis. An antibiotic susceptibility test was performed using antibiotics based on their mode of action. A biofilm assay was performed to assess the adhesion potential of the isolates. RESULTS A total of 25 bacterial isolates were identified from the water samples, including Acinetobacter junii, Acinetobacter pittii, Acinetobacter haemolyticus, Bacillus pumilus, Bacillus megaterium, Bacillus marisflavi, Bacillus flexus, Bacillus oceanisediminis, Pseudomonas otitidis, Pseudomonas sp. RR013, Pseudomonas sp. RR021, Pseudomonas sp. RR022, Escherichia coli and Enterobacter cloacae. The results of the antimicrobial susceptibility test revealed that the antibiotics cefodroxil, aztreonam, nitrofurantoin, cefepime, ceftazidime and amoxyclav were found to be mostly ineffective against various isolates. The biofilm assay revealed the weak, moderate and strong biofilm producers among them. CONCLUSIONS The tap water in the public toilets was microbially contaminated and needs to be monitored carefully. The antibiotic susceptibility profile showed that of 25 bacterial isolates, 5 were multidrug resistant. Bacterial isolates exhibited strong to weak adhesion potential in the biofilm assay.
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Affiliation(s)
- Rajanbir Kaur
- Department of Botanical and Environmental Sciences, Guru Nanak Dev University, Amritsar, Punjab 143005, India
| | - Drishtant Singh
- Department of Molecular Biology and Biochemistry, Guru Nanak Dev University, Amritsar, Punjab 143005, India
| | - Anup Kumar Kesavan
- Department of Molecular Biology and Biochemistry, Guru Nanak Dev University, Amritsar, Punjab 143005, India
| | - Rajinder Kaur
- Department of Botanical and Environmental Sciences, Guru Nanak Dev University, Amritsar, Punjab 143005, India
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Cosgaya C, Ratia C, Marí-Almirall M, Rubio L, Higgins PG, Seifert H, Roca I, Vila J. In vitro and in vivo Virulence Potential of the Emergent Species of the Acinetobacter baumannii (Ab) Group. Front Microbiol 2019; 10:2429. [PMID: 31708900 PMCID: PMC6821683 DOI: 10.3389/fmicb.2019.02429] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 10/08/2019] [Indexed: 01/30/2023] Open
Abstract
The increased use of molecular identification methods and mass spectrometry has revealed that Acinetobacter spp. of the A. baumannii (Ab) group other than A. baumannii are increasingly being recovered from human samples and may pose a health challenge if neglected. In this study 76 isolates of 5 species within the Ab group (A. baumannii n = 16, A. lactucae n = 12, A. nosocomialis n = 16, A. pittii n = 20, and A. seifertii n = 12), were compared in terms of antimicrobial susceptibility, carriage of intrinsic resistance genes, biofilm formation, and the ability to kill Caenorhabditis elegans in an infection assay. In agreement with previous studies, antimicrobial resistance was common among A. baumannii while all other species were generally more susceptible. Carriage of genes encoding different efflux pumps was frequent in all species and the presence of intrinsic class D β-lactamases was reported in A. baumannii, A. lactucae (heterotypic synonym of A. dijkshoorniae) and A. pittii but not in A. nosocomialis and A. seifertii. A. baumannii and A. nosocomialis presented weaker pathogenicity in our in vitro and in vivo models than A. seifertii, A. pittii and, especially, A. lactucae. Isolates from the former species showed decreased biofilm formation and required a longer time to kill C. elegans nematodes. These results suggest relevant differences in terms of antibiotic susceptibility patterns among the members of the Ab group as well as highlight a higher pathogenicity potential for the emerging species of the group in this particular model. Nevertheless, the impact of such potential in the human host still remains to be determined.
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Affiliation(s)
- Clara Cosgaya
- ISGlobal, Hospital Clínic - University of Barcelona, Barcelona, Spain
| | - Carlos Ratia
- ISGlobal, Hospital Clínic - University of Barcelona, Barcelona, Spain
| | | | - Laia Rubio
- ISGlobal, Hospital Clínic - University of Barcelona, Barcelona, Spain
| | - Paul G Higgins
- Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Cologne, Germany.,German Center for Infection Research (DZIF), Bonn, Germany
| | - Harald Seifert
- Institute for Medical Microbiology, Immunology and Hygiene, University of Cologne, Cologne, Germany.,German Center for Infection Research (DZIF), Bonn, Germany
| | - Ignasi Roca
- ISGlobal, Hospital Clínic - University of Barcelona, Barcelona, Spain
| | - Jordi Vila
- ISGlobal, Hospital Clínic - University of Barcelona, Barcelona, Spain
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11
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Radó J, Kaszab E, Benedek T, Kriszt B, Szoboszlay S. First isolation of carbapenem-resistant Acinetobacter beijerinckii from an environmental sample. Acta Microbiol Immunol Hung 2019; 66:113-130. [PMID: 30816807 DOI: 10.1556/030.66.2019.004] [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] [Indexed: 11/19/2022]
Abstract
The emergence of opportunistic Acinetobacter spp. in healthcare settings poses a significant threat to public health. The major reasons for nosocomial spread of these species are their abilities to develop and transfer drug resistance against various classes of antibiotics. Considering that Acinetobacter spp. are ubiquitous in nature, can utilize several carbon sources, and reach humans via various pathways, our aim was to obtain information about the environmental strains of this genus. Our first step was to develop and test a multistep isolation procedure based on traditional scientific methods. Antibiotic resistance patterns of the isolated strains were determined, as susceptibility to 12 antibiotics of 7 classes was tested by MIC Test Strip method. Altogether 366 samples (groundwater, surface water, and soil) of 24 sites were investigated and a collection of 37 Acinetobacter isolates was obtained. Among others, clinically important human pathogen Acinetobacter spp., such as A. baumannii, A. johnsonii, and A. gyllenbergii were identified. Three environmental strains were determined as multidrug-resistant including a carbapenem-resistant, hemolytic Acinetobacter beijerinckii strain isolated from a hydrocarbon-contaminated groundwater sample. In summary, it has been found that the applied multistep isolation procedure is applicable to isolate various species of Acinetobacter genus. Based on the antibiotic resistance assay, we can conclude that environmental representatives of Acinetobacter spp. are able to develop multidrug resistance, but at a lower rate than their clinical counterparts.
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Affiliation(s)
- Júlia Radó
- 1 Department of Environmental Safety and Ecotoxicology, Szent István University, Gödöllő, Hungary
| | - Edit Kaszab
- 1 Department of Environmental Safety and Ecotoxicology, Szent István University, Gödöllő, Hungary
| | - Tibor Benedek
- 2 Regional University Center of Excellence, Szent István University, Gödöllő, Hungary
| | - Balázs Kriszt
- 1 Department of Environmental Safety and Ecotoxicology, Szent István University, Gödöllő, Hungary
| | - Sándor Szoboszlay
- 1 Department of Environmental Safety and Ecotoxicology, Szent István University, Gödöllő, Hungary
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12
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A Prospective Study of Acinetobacter baumannii Complex Isolates and Colistin Susceptibility Monitoring by Mass Spectrometry of Microbial Membrane Glycolipids. J Clin Microbiol 2019; 57:JCM.01100-18. [PMID: 30567747 DOI: 10.1128/jcm.01100-18] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 12/13/2018] [Indexed: 11/20/2022] Open
Abstract
Acinetobacter baumannii is a prevalent nosocomial pathogen with a high incidence of multidrug resistance. Treatment of infections due to this organism with colistin, a last-resort antibiotic of the polymyxin class, can result in the emergence of colistin-resistant strains. Colistin resistance primarily occurs via modifications of the terminal phosphate moieties of lipopolysaccharide-derived lipid A, which reduces overall membrane electronegativity. These modifications are readily identified by mass spectrometry (MS). In this study, we prospectively collected Acinetobacter baumannii complex clinical isolates from a hospital system in Pennsylvania over a 3-year period. All isolates were evaluated for colistin resistance using standard MIC testing by both agar dilution and broth microdilution, as well as genospecies identification and lipid A profiling using MS analyses. Overall, an excellent correlation between colistin susceptibility and resistance, determined by MIC testing, and the presence of a lipid A modification, determined by MS, was observed with a sensitivity of 92.9% and a specificity of 94.0%. Additionally, glycolipid profiling was able to differentiate A. baumannii complex organisms based on their membrane lipids. With the growth of MS use in clinical laboratories, a reliable MS-based glycolipid phenotyping method that identifies colistin resistance in A. baumannii complex clinical isolates, as well as other Gram-negative organisms, represents an alternative or complementary approach to existing diagnostics.
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13
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Benmahmod AB, Said HS, Ibrahim RH. Prevalence and Mechanisms of Carbapenem Resistance Among Acinetobacter baumannii Clinical Isolates in Egypt. Microb Drug Resist 2018; 25:480-488. [PMID: 30394846 DOI: 10.1089/mdr.2018.0141] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The increasing number of carbapenem-resistant Acinetobacter baumannii clinical isolates is a major concern, which restricts therapeutic options for treatment of serious infections caused by this emerging pathogen. The aim of this work is to assess the antimicrobial resistance profile and identify the molecular mechanisms involved in carbapenem resistance in A. baumannii isolated from different clinical sources in Mansoura University Hospitals, Egypt. Antimicrobial susceptibility testing has shown that resistance to carbapenem has dramatically increased (98%) with concomitant elevated levels of resistance to quinolones, trimethoprim/sulfamethoxazole, and aminoglycosides. Polymyxin B and colistin are considered the last resort. Random amplified polymorphic DNA (RAPD) typing method revealed great diversity among A. baumannii isolates. Coexistence of diverse intrinsic and acquired carbapenem-hydrolyzing β-lactamases has been detected in the tested isolates: Ambler class A: blaKPC (56%) and blaGES (48%), and Ambler class B: blaNDM (30%), blaSIM (28%), blaVIM (20%), and blaIMP (10%). Most isolates (94%) carried blaOXA-23-like and blaOXA-51-like simultaneously. blaOXA-23-like was preceded by ISAba1 providing a potent promoter activity for its expression. Sequencing analysis revealed that ISAba1 has been also inserted in carbapenem resistance-associated outer membrane protein (OMP) (carO) gene in three isolates, two of which were clonal based on RAPD typing, leading to interruption of its expression as confirmed by SDS-PAGE analysis of OMP fractions. Carbapenem resistance genes are widely distributed among A. baumannii clinical isolates from different clinical sources. Therefore, enhanced infection control measures, effective barriers, and rational use of antimicrobials should be enforced in hospitals for minimizing the widespread resistance to carbapenems and all other antibiotics.
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Affiliation(s)
| | - Heba Shehta Said
- Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt
| | - Ramdan Hassan Ibrahim
- Department of Microbiology and Immunology, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt
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Comparison of clinical manifestations and antibiotic resistances among three genospecies of the Acinetobacter calcoaceticus-Acinetobacter baumannii complex. PLoS One 2018; 13:e0191748. [PMID: 29389980 PMCID: PMC5794090 DOI: 10.1371/journal.pone.0191748] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 01/10/2018] [Indexed: 01/26/2023] Open
Abstract
The Acinetobacter calcoaceticus-Acinetobacter baumannii (ACB) complex has emerged as a high priority among hospital-acquired pathogens in intensive care units (ICUs), posing a challenge to infection management practices. In this study, the clinical characteristics, antimicrobial susceptibility patterns, and patients outcome among genospecies were retrospectively compared. Samples were taken from the tracheal secretions of 143 patients in the ICU. Genospecies of the ACB complex were discriminated by analysis of the 16S-23S rRNA gene intergenic spacer (ITS) sequence. Univariate and multiple variable logistic regression analyses were performed to identify risk factors for infection and mortality. Three genospecies were isolated: A. baumannii (73, 51.0%), A. nosocomialis (29, 20.3%), and A. pittii (41, 28.7%). The results showed that the distribution of infection and colonization among the three genospecies were the same, while A. baumannii was more resistant to common antibiotics than A. nosocomialis and A. pittii. Advanced age, a long stay in the ICU, acute physiology and chronic health evaluation (APACHE) II score, the use of a mechanical ventilator, and previous antibiotic use were risk factors for patient infection. The APACHE II score was a risk factor for mortality in patients with ACB complex isolated from tracheal secretions. Poor outcome of patients with ACB complex isolated from tracheal secretion appears to be related to the APACHE II score rather than genospecies.
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15
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Acinetobacter pittii, an emerging new multi-drug resistant fish pathogen isolated from diseased blunt snout bream (Megalobrama amblycephala Yih) in China. Appl Microbiol Biotechnol 2017; 101:6459-6471. [DOI: 10.1007/s00253-017-8392-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 04/25/2017] [Accepted: 06/14/2017] [Indexed: 11/25/2022]
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16
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MALDI-TOF/MS identification of species from the Acinetobacter baumannii (Ab) group revisited: inclusion of the novel A. seifertii and A. dijkshoorniae species. Clin Microbiol Infect 2016; 23:210.e1-210.e9. [PMID: 27919649 DOI: 10.1016/j.cmi.2016.11.020] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 11/28/2016] [Accepted: 11/28/2016] [Indexed: 12/22/2022]
Abstract
OBJECTIVES Rapid identification of Acinetobacter species is critical as members of the A. baumannii (Ab) group differ in antibiotic susceptibility and clinical outcomes. A. baumannii, A. pittii, and A. nosocomialis can be identified by MALDI-TOF/MS, while the novel species A. seifertii and A. dijkshoorniae cannot. Low identification rates for A. nosocomialis also have been reported. We evaluated the use of MALDI-TOF/MS to identify isolates of A. seifertii and A. dijkshoorniae and revisited the identification of A. nosocomialis to update the Bruker taxonomy database. METHODS Species characterization was performed by rpoB-clustering and MLSA. MALDI-TOF/MS spectra were recovered from formic acid/acetonitrile bacterial extracts overlaid with α-cyano-4-hydroxy-cinnamic acid matrix on a MicroflexLT in linear positive mode and 2000-20 000 m/z range mass. Spectra were examined with the ClinProTools v2.2 software. Mean spectra (MSP) were created with the BioTyper software. RESULTS Seventy-eight Acinetobacter isolates representative of the Ab group were used to calculate the average spectra/species and generate pattern recognition models. Species-specific peaks were identified for all species, and MSPs derived from three A. seifertii, two A. dijkshoorniae, and two A. nosocomialis strains were added to the Bruker taxonomy database, allowing successful identification of all isolates using spectra from either bacterial extracts or direct colonies, resulting in a positive predictive value (PPV) of 99.6% (777/780) and 96.8% (302/312), respectively. CONCLUSIONS The use of post-processing data software identified statistically significant species-specific peaks to generate reference signatures for rapid accurate identification of species within the Ab group, providing relevant information for the clinical management of Acinetobacter infections.
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Jain AL, Harding CM, Assani K, Shrestha CL, Haga M, Leber A, Munson RS, Kopp BT. Characteristics of invasive Acinetobacter species isolates recovered in a pediatric academic center. BMC Infect Dis 2016; 16:346. [PMID: 27449800 PMCID: PMC4957376 DOI: 10.1186/s12879-016-1678-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 06/14/2016] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Acinetobacter species are associated with increasing mortality due to emerging drug-resistance. Pediatric Acinetobacter infections are largely undefined in developed countries and clinical laboratory identification methods do not reliably differentiate between members of the Acinetobacter calcoaceticus-baumannii complex, leading to improper identification. Therefore we aimed to determine risk factors for invasive Acinetobacter infections within an academic, pediatric setting as well as defining microbiologic characteristics of predominant strains. METHODS Twenty-four invasive Acinetobacter isolates were collected from 2009-2013. Comparative sequence analysis of the rpoB gene was performed coupled with phenotypic characterization of antibiotic resistance, motility, biofilm production and clinical correlation. RESULTS Affected patients had a median age of 3.5 years, and 71 % had a central catheter infection source. rpoB gene sequencing revealed a predominance of A. pittii (45.8 %) and A. baumannii (33.3 %) strains. There was increasing incidence of A. pittii over the study. Two fatalities occurred in the A. pittii group. Seventeen percent of isolates were multi-drug resistant. A pittii and A. baumannii strains were similar in motility, but A pittii strains had significantly more biofilm production (P value = 0.018). CONCLUSIONS A. pittii was the most isolated species highlighting the need for proper species identification. The isolated strains had limited acute mortality in children, but the occurrence of more multi-drug resistant strains in the future is a distinct possibility, justifying continued research and accurate species identification.
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Affiliation(s)
- Avish L Jain
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Christian M Harding
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
- Biomedical Sciences Graduate Program, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Kaivon Assani
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Chandra L Shrestha
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Mercedees Haga
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Amy Leber
- Department of Laboratory Medicine, Nationwide Children's Hospital, Columbus, OH, USA
| | - Robert S Munson
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Benjamin T Kopp
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA.
- Nationwide Children's Hospital, Section of Pulmonary Medicine, 700 Children's Drive, Columbus, OH, 43205, USA.
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18
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Tian S, Ali M, Xie L, Li L. Genome-sequence analysis of Acinetobacter johnsonii MB44 reveals potential nematode-virulent factors. SPRINGERPLUS 2016; 5:986. [PMID: 27429894 PMCID: PMC4932006 DOI: 10.1186/s40064-016-2668-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 06/25/2016] [Indexed: 02/05/2023]
Abstract
Acinetobacter johnsonii is generally recognized as a nonpathogenic bacterium although it is often found in hospital environments. However, a newly identified isolate of this species from a frost-plant-tissue sample, namely, A. johnsonii MB44, showed significant nematicidal activity against the model organism Caenorhabditis elegans. To expand our understanding of this bacterial species, we generated a draft genome sequence of MB44 and analyzed its genomic features related to nematicidal attributes. The 3.36 Mb long genome contains 3636 predicted protein-coding genes and 95 RNA genes (including 14 rRNA genes), with a G + C content of 41.37 %. Genomic analysis of the prediction of nematicidal proteins using the software MP3 revealed a total of 108 potential virulence proteins. Some of these proteins were homologous to the known virulent proteins identified from Acinetobacter baumannii, a pathogenic species of the genus Acinetobacter. These virulent proteins included the outer membrane protein A, the phospholipase D, and penicillin-binding protein 7/8. Moreover, one siderophore biosynthesis gene cluster and one capsular polysaccharide gene cluster, which were predicted to be important virulence factors for C. elegans, were identified in the MB44 genome. The current study demonstrated that A. johnsonii MB44, with its nematicidal activity, could be an opportunistic pathogen to animals.
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Affiliation(s)
- Shijing Tian
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070 Hubei Province China
| | - Muhammad Ali
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070 Hubei Province China ; Biotechnology Program, Department of Environmental Sciences, COMSATS Institute of Information Technology, Abbottabad, Pakistan
| | - Li Xie
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070 Hubei Province China
| | - Lin Li
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070 Hubei Province China
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Fujikura Y, Yuki A, Hamamoto T, Kawana A, Ohkusu K, Matsumoto T. Blood stream infections caused by Acinetobacter baumannii group in Japan - Epidemiological and clinical investigation. J Infect Chemother 2016; 22:366-71. [PMID: 26993173 DOI: 10.1016/j.jiac.2016.02.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 01/06/2016] [Accepted: 02/17/2016] [Indexed: 11/18/2022]
Abstract
Acinetobacter calcoaceticus-Acinetobacter baumannii complex, especially A. baumannii, Acinetobacter pittii and Acinetobacter nosocomialis, constitutes an important group of nosocomial pathogens; however, epidemiological or clinical characteristics and prognosis is limited in Japan. From 2009 to 2013, 47 blood stream infection cases resulting from A. baumannii group were reviewed at the National Defense Medical College, an 800-bed tertiary hospital. To determine the genospecies, further comparative nucleotide sequence analyses of the RNA polymerase b-subunit (rpoB) gene were performed. Sequence analysis of rpoB gene showed that 25 (49.0%), 17 (33.3%) and 5 (9.8%) cases were caused by A. baumannii, A. pittii and A. nosocomialis, respectively. The 30-day and in-hospital mortality rates of A. baumannii were 8.5% and 25.5%, respectively, and there were no significant differences between Acinetobacter species. Clinical characteristics were statistically insignificant. Multidrug-resistant Acinetobacter species were detected in 3 cases (5.9%) with same pulsed-field gel electrophoresis (PFGE) pattern and A. baumannii was less susceptible to amikacin and levofloxacin. In this study, the mortality and clinical characteristics were similar among A. baumannii group isolate cases despite some showing drug resistance. However, identification of Acinetobacter species helps to initiate appropriate antibiotic therapy in earlier treatment phase, because A. baumannii shows some drug resistance.
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Affiliation(s)
- Yuji Fujikura
- Department of Microbiology, Tokyo Medical University, 6-1-1 Shinjyuku, Shinjyuku-ku, Tokyo 160-8402, Japan; Division of Infectious Diseases and Respiratory Medicine, Department of Internal Medicine, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan.
| | - Atsushi Yuki
- Department of Clinical Laboratory, National Defense Medical College Hospital, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan
| | - Takaaki Hamamoto
- Department of Clinical Laboratory, National Defense Medical College Hospital, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan
| | - Akihiko Kawana
- Division of Infectious Diseases and Respiratory Medicine, Department of Internal Medicine, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan
| | - Kiyofumi Ohkusu
- Department of Microbiology, Tokyo Medical University, 6-1-1 Shinjyuku, Shinjyuku-ku, Tokyo 160-8402, Japan
| | - Tetsuya Matsumoto
- Department of Microbiology, Tokyo Medical University, 6-1-1 Shinjyuku, Shinjyuku-ku, Tokyo 160-8402, Japan
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Medically Relevant Acinetobacter Species Require a Type II Secretion System and Specific Membrane-Associated Chaperones for the Export of Multiple Substrates and Full Virulence. PLoS Pathog 2016; 12:e1005391. [PMID: 26764912 PMCID: PMC4713064 DOI: 10.1371/journal.ppat.1005391] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 12/18/2015] [Indexed: 01/31/2023] Open
Abstract
Acinetobacter baumannii, A. nosocomialis, and A. pittii have recently emerged as opportunistic human pathogens capable of causing severe human disease; however, the molecular mechanisms employed by Acinetobacter to cause disease remain poorly understood. Many pathogenic members of the genus Acinetobacter contain genes predicted to encode proteins required for the biogenesis of a type II secretion system (T2SS), which have been shown to mediate virulence in many Gram-negative organisms. Here we demonstrate that Acinetobacter nosocomialis strain M2 produces a functional T2SS, which is required for full virulence in both the Galleria mellonella and murine pulmonary infection models. Importantly, this is the first bona fide secretion system shown to be required for virulence in Acinetobacter. Using bioinformatics, proteomics, and mutational analyses, we show that Acinetobacter employs its T2SS to export multiple substrates, including the lipases LipA and LipH as well as the protease CpaA. Furthermore, the Acinetobacter T2SS, which is found scattered amongst five distinct loci, does not contain a dedicated pseudopilin peptidase, but instead relies on the type IV prepilin peptidase, reinforcing the common ancestry of these two systems. Lastly, two of the three secreted proteins characterized in this study require specific chaperones for secretion. These chaperones contain an N-terminal transmembrane domain, are encoded adjacently to their cognate effector, and their disruption abolishes type II secretion of their cognate effector. Bioinformatic analysis identified putative chaperones located adjacent to multiple previously known type II effectors from several Gram-negative bacteria, which suggests that T2SS chaperones constitute a separate class of membrane-associated chaperones mediating type II secretion.
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21
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Toh BEW, Paterson DL, Kamolvit W, Zowawi H, Kvaskoff D, Sidjabat H, Wailan A, Peleg AY, Huber CA. Species identification within Acinetobacter calcoaceticus-baumannii complex using MALDI-TOF MS. J Microbiol Methods 2015; 118:128-32. [PMID: 26381662 DOI: 10.1016/j.mimet.2015.09.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 09/09/2015] [Accepted: 09/10/2015] [Indexed: 11/27/2022]
Abstract
Acinetobacter baumannii, one of the more clinically relevant species in the Acinetobacter genus is well known to be multi-drug resistant and associated with bacteremia, urinary tract infection, pneumonia, wound infection and meningitis. However, it cannot be differentiated from closely related species such as Acinetobacter calcoaceticus, Acinetobacter pittii and Acinetobacter nosocomialis by most phenotypic tests and can only be differentiated by specific, time consuming genotypic tests with very limited use in clinical microbiological laboratories. As a result, these species are grouped into the A. calcoaceticus-A. baumannii (Acb) complex. Herein we investigated the mass spectra of 73 Acinetobacter spp., representing ten different species, using an AB SCIEX 5800 MALDI-TOF MS to differentiate members of the Acinetobacter genus, including the species of the Acb complex. RpoB gene sequencing, 16S rRNA sequencing, and gyrB multiplex PCR were also evaluated as orthogonal methods to identify the organisms used in this study. We found that whilst 16S rRNA and rpoB gene sequencing could not differentiate A. pittii or A. calcoaceticus, they can be differentiated using gyrB multiplex PCR and MALDI-TOF MS. All ten Acinetobacter species investigated could be differentiated by their MALDI-TOF mass spectra.
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Affiliation(s)
- Benjamin E W Toh
- The University of Queensland, UQ Centre for Clinical Research, Queensland, Royal Brisbane and Women's Hospital Campus, Brisbane, Australia
| | - David L Paterson
- The University of Queensland, UQ Centre for Clinical Research, Queensland, Royal Brisbane and Women's Hospital Campus, Brisbane, Australia
| | - Witchuda Kamolvit
- The University of Queensland, UQ Centre for Clinical Research, Queensland, Royal Brisbane and Women's Hospital Campus, Brisbane, Australia
| | - Hosam Zowawi
- The University of Queensland, UQ Centre for Clinical Research, Queensland, Royal Brisbane and Women's Hospital Campus, Brisbane, Australia; King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia; World Health Organization Collaborating Centre for Infection Prevention and Control, and Gulf Cooperation Council Center for Infection Control, Riyadh, Saudi Arabia
| | - David Kvaskoff
- The University of Queensland, UQ Centre for Clinical Research, Queensland, Royal Brisbane and Women's Hospital Campus, Brisbane, Australia
| | - Hanna Sidjabat
- The University of Queensland, UQ Centre for Clinical Research, Queensland, Royal Brisbane and Women's Hospital Campus, Brisbane, Australia
| | - Alexander Wailan
- The University of Queensland, UQ Centre for Clinical Research, Queensland, Royal Brisbane and Women's Hospital Campus, Brisbane, Australia
| | - Anton Y Peleg
- Department of Infectious Diseases, Alfred Hospital, Melbourne, Australia; Department of Microbiology, Monash University, Melbourne, Australia
| | - Charlotte A Huber
- The University of Queensland, UQ Centre for Clinical Research, Queensland, Royal Brisbane and Women's Hospital Campus, Brisbane, Australia.
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Identification of NDM-1 in a Putatively Novel Acinetobacter Species ("NB14") Closely Related to Acinetobacter pittii. Antimicrob Agents Chemother 2015; 59:6657-60. [PMID: 26259796 DOI: 10.1128/aac.01455-15] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2015] [Accepted: 08/04/2015] [Indexed: 11/20/2022] Open
Abstract
In this study, we describe the molecular characterization of a plasmid-located blaNDM-1 harbored by an Acinetobacter clinical isolate recovered from a patient in Turkey that putatively constitutes a novel Acinetobacter species, as shown by its distinct ARDRA (amplified 16S ribosomal DNA restriction analysis) profile and molecular sequencing techniques. blaNDM-1 was carried by a conjugative plasmid widespread among non-baumannii Acinetobacter isolates, suggesting its potential for dissemination before reaching more clinically relevant Acinetobacter species.
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Kamolvit W, Sidjabat HE, Paterson DL. Molecular Epidemiology and Mechanisms of Carbapenem Resistance ofAcinetobacterspp. in Asia and Oceania. Microb Drug Resist 2015; 21:424-34. [DOI: 10.1089/mdr.2014.0234] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Witchuda Kamolvit
- UQ Centre of Clinical Research, The University of Queensland, Brisbane, Australia
- Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Hanna E. Sidjabat
- UQ Centre of Clinical Research, The University of Queensland, Brisbane, Australia
| | - David L. Paterson
- UQ Centre of Clinical Research, The University of Queensland, Brisbane, Australia
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Bahador A, Raoofian R, Farshadzadeh Z, Beitollahi L, Khaledi A, Rahimi S, Mokhtaran M, Mehrabi Tavana A, Esmaeili D. The Prevalence of IS Aba 1 and IS Aba 4 in Acinetobacter baumannii Species of Different International Clone Lineages Among Patients With Burning in Tehran, Iran. Jundishapur J Microbiol 2015; 8:e17167. [PMID: 26396712 PMCID: PMC4575776 DOI: 10.5812/jjm.17167v2] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Revised: 04/20/2014] [Accepted: 04/27/2014] [Indexed: 11/18/2022] Open
Abstract
Background: Multidrug resistant strains of Acinetobacter baumannii (MDR-AB) have emerged as alarming nosocomial pathogens among patients with burning. Objectives: The current study aimed to determine the susceptibility of A. baumannii species, carbapenems resistance patterns, and their association with ISAba1 and ISAba4 elements upstream of the blaOXA-like genes, and the distribution of international clone (IC) of A. baumannii isolates among patients with burning in Tehran, Iran. Materials and Methods: In the current study, 62 A. baumannii species isolates from patients with burning in Tehran, Iran, in 2012 were evaluated for the antimicrobial susceptibility, genetic relationships, ICs, carbapenemase encoding genes, and insertion elements ISAba upstream of blaOXA-like genes. Results: The highest rates of susceptibility were observed with colistin (88.7%) and tigecycline (82.2%). The extensively drug-resistance and pan drug-resistance were observed in 37.1% and 8.1% of the isolates, respectively. About 98.3% of 17 genotypes categorized into three distinct clusters. Thirty-six of the 62 isolates (58%) belonged to the IC II lineage. The most prevalent acquired OXA-type carbapenemase was blaOXA-23-like (62.9%). ISAba1 and ISAba4 were detected upstream of blaOXA-23-like genes in 45.1% and 12.9% of isolates, respectively. In 32.2% of all isolates, ISAba1 laid upstream of blaOXA-51-like genes. The PCR results were negative for carbapenemase genes of Ambler class A and B, except blaVIM-2. (1.6%). Conclusions: It was the first study that attempted to detect the insertion elements ISAba and IC lineages in MDR-AB species isolated from patients with burning in Iran.
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Affiliation(s)
- Abbas Bahador
- Department of Microbiology, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, IR Iran
| | - Reza Raoofian
- Department of Genetic, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, IR Iran
| | - Zahra Farshadzadeh
- Department of Microbiology, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, IR Iran
| | - Leyli Beitollahi
- Department of Microbiology, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, IR Iran
| | - Azad Khaledi
- Department of Microbiology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, IR Iran
| | - Sara Rahimi
- Department of Microbiology, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, IR Iran
| | - Masoumeh Mokhtaran
- Department of Microbiology, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, IR Iran
| | - Ali Mehrabi Tavana
- Health Management Research Center, Baqiyatallah University of Medical Sciences, Tehran, IR Iran
| | - Davood Esmaeili
- Applied Microbiology Research Center, Department of Microbiology, Baqiyatallah University of Medical Sciences, Tehran, IR Iran
- Corresponding author: Davood Esmaeili, Applied Microbiology Research Center, Department of Microbiology, Baqiyatallah University of Medical Sciences, Tehran, IR Iran. Tel: +98-2188067969, Fax: +98-2188039883, E-mail:
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A case of IMP-4-, OXA-421-, OXA-96-, and CARB-2-producing Acinetobacter pittii sequence type 119 in Australia. J Clin Microbiol 2014; 53:727-30. [PMID: 25428154 DOI: 10.1128/jcm.02726-14] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
An IMP-4-producing Acinetobacter pittii strain coproducing oxacillinases was isolated from a leg wound of a 67-year-old female patient. Identification to the species level by rpoB and gyrB sequencing and multiplex-PCR-based analysis revealed that the isolate was A. pittii. Whole-genome sequencing of this A. pittii isolate determined the presence of blaOXA-96, blaCARB-2, and a novel blaOXA-421 gene. The position of this novel blaOXA-421 gene was similar to that of blaOXA-51 in A. baumannii, downstream of the phosphinothricin N-acetyltransferase gene and upstream of fxsA in the chromosome. This A. pittii isolate was found to belong to sequence type 119 (ST119). Here, we report the first isolation of IMP-4-producing A. pittii ST119 with a novel blaOXA-421 gene from a patient in Australia and characterize its draft genome.
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Nasrolahei M, Zahedi B, Bahador A, Saghi H, Kholdi S, Jalalvand N, Esmaeili D. Distribution of bla(OXA-23), ISAba , Aminoglycosides resistant genes among burned & ICU patients in Tehran and Sari, Iran. Ann Clin Microbiol Antimicrob 2014; 13:38. [PMID: 25252850 PMCID: PMC4353670 DOI: 10.1186/s12941-014-0038-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 07/16/2014] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Multidrug resistant strains of Acinetobacter baumannii (MDR-AB) have emerged as alarming nosocomial pathogens among patients admitted to Intensive Care Unit and burned patients. The aim of this study was to determine the susceptibility of A. baumannii isolates, the carbapenems resistance patterns bla(OXA-23) and also ISAba elements of A. baumannii isolates among burned and ICU patients in Tehran and Sari, Iran. METHODS In this study, 100 A. baumannii isolates from burned and ICU patients in Tehran and Sari (Iran) during 2013 were tested for determination of antimicrobials susceptibility by the disc-diffusion method on Mueller Hinton agar recommended by the guidelines of Clinical and Laboratory Standards Institute (CLSI), and frequency bla(OXA-23) carbapenemase genes, and insertion elements ISAba genes were studied by PCR method. RESULTS The highest rates of susceptibility were observed with Colistin (88.7%), Tigecycline (82.2%), Imipenem (67%) and ISAba (32.2%). The extensively drug-resistance and pan drug-resistance were observed in 37.1% and 8.1% isolates, respectively. Results indicated among isolates resistant to Aminoglycoside and Carbapenem, the highest resistance was observed to Streptomycin (90%) ' and the most sensitivity was to Imipenem (67%). CONCLUSIONS This is the most study that attempted to detect Acinetobacter baumanii the insertion elements ISAba , bla(OXA-23) and aminoglycosides resistance in MDR-AB isolates from burned and ICU patients in Iran. In a timely manner, antimicrobial resistance surveillance and strict infection control strategies are still lacking in burn ward and ICU in Iran, despite the alarming emergence of MDR-AB strains, particularly among those isolates that are not susceptible to Colistin. The results of this study are consistent with a recent report in which a number of combinations exhibited potent activity against Multidrug resistant strains of A. baumannii (MDR-AB).
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Affiliation(s)
- Mohtaram Nasrolahei
- Department of Microbiology, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran.
| | - Bahador Zahedi
- Department of Microbiology, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran.
| | - Abbas Bahador
- Departments of Microbiology, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
| | - Hossein Saghi
- Applied Microbiology Research center and Microbiology Department, Baqiyatallah University Medical of Sciences, Tehran, Iran.
| | - Soudeh Kholdi
- Department of Microbiology, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran.
| | - Neda Jalalvand
- Department of Genetic' Science and Research Branch, Islamic Azad University, Tabriz, East Azerbaijan, Iran.
| | - Davoud Esmaeili
- Applied Microbiology Research center and Microbiology Department, Baqiyatallah University Medical of Sciences, Tehran, Iran.
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Qu J, Zong Z, Yu R, Hu T, Ye H, Lu X. Impact of test methodology, media type and ion content on the susceptibility of Acinetobacter spp. to tigecycline. J Antimicrob Chemother 2014; 69:1710-1. [DOI: 10.1093/jac/dkt546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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