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Alnimr A. Antimicrobial Resistance in Ventilator-Associated Pneumonia: Predictive Microbiology and Evidence-Based Therapy. Infect Dis Ther 2023:10.1007/s40121-023-00820-2. [PMID: 37273072 DOI: 10.1007/s40121-023-00820-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Accepted: 05/09/2023] [Indexed: 06/06/2023] Open
Abstract
Ventilator-associated pneumonia (VAP) is a serious intensive care unit (ICU)-related infection in mechanically ventilated patients that is frequent, as more than half of antibiotics prescriptions in ICU are due to VAP. Various risk factors and diagnostic criteria for VAP have been referred to in different settings. The estimated attributable mortality of VAP can go up to 50%, which is higher in cases of antimicrobial-resistant VAP. When the diagnosis of pneumonia in a mechanically ventilated patient is made, initiation of effective antimicrobial therapy must be prompt. Microbiological diagnosis of VAP is required to optimize timely therapy since effective early treatment is fundamental for better outcomes, with controversy continuing regarding optimal sampling and testing. Understanding the role of antimicrobial resistance in the context of VAP is crucial in the era of continuously evolving antimicrobial-resistant clones that represent an urgent threat to global health. This review is focused on the risk factors for antimicrobial resistance in adult VAP and its novel microbiological tools. It aims to summarize the current evidence-based knowledge about the mechanisms of resistance in VAP caused by multidrug-resistant bacteria in clinical settings with focus on Gram-negative pathogens. It highlights the evidence-based antimicrobial management and prevention of drug-resistant VAP. It also addresses emerging concepts related to predictive microbiology in VAP and sheds lights on VAP in the context of coronavirus disease 2019 (COVID-19).
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Affiliation(s)
- Amani Alnimr
- Department of Microbiology, College of Medicine, King Fahad Hospital of the University, Imam Abdulrahman Bin Faisal University, Dammam, Kingdom of Saudi Arabia.
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Yan J, Yilin H, Di W, Jie W, Hanyue W, Ya L, Jie P. A nomogram for predicting the risk of mortality in patients with acute pancreatitis and Gram-negative bacilli infection. Front Cell Infect Microbiol 2022; 12:1032375. [PMID: 36439207 PMCID: PMC9685314 DOI: 10.3389/fcimb.2022.1032375] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 10/25/2022] [Indexed: 08/15/2023] Open
Abstract
OBJECTIVE Gram-negative bacilli (GNB) are common pathogens of infection in severe acute pancreatitis (SAP), and their occurrence increases the mortality of SAP. Early identification of SAP severity and prognosis is of great significance to SAP treatment. This study explored risk factors for mortality in patients with SAP and GNB infection and established a model for early prediction of the risk of death in GNB-infected SAP patients. METHODS Patients diagnosed with SAP from January 1, 2016, to March 31, 2022, were included, and their baseline clinical characteristics were collected. Univariate logistic regression analysis was performed to screen for death related variables, and concurrently, a Boruta analysis was performed to identify potentially important clinical features associated with mortality. The intersection of the two results was taken for further multivariate logistic regression analysis. A logistic regression model was constructed according to the independent risk factor of death and then visualized with a nomogram. The performance of the model was further validated in the training and validation cohort. RESULTS A total of 151 patients with SAP developed GNB infections. Univariate logistic regression analysis identified 11 variables associated with mortality. The Boruta analysis identified 11 clinical features, and 4 out of 9 clinical variables: platelet counts (odds ratio [OR] 0.99, 95% confidence interval [CI] 0.99-1.00; p = 0.007), hemoglobin (OR 0.96, 95% CI 0.92-1; p = 0.037), septic shock (OR 6.33, 95% CI 1.12-43.47; p = 0.044), and carbapenem resistance (OR 7.99, 95% CI 1.66-52.37; p = 0.016), shared by both analyses were further selected as independent risk factors by multivariate logistic regression analysis. A nomogram was used to visualize the model. The model demonstrated good performance in both training and validation cohorts with recognition sensitivity and specificity of 96% and 80% in the training cohort and 92.8% and 75% in the validation cohort, respectively. CONCLUSION The nomogram can accurately predict the mortality risk of patients with SAP and GNB infection. The clinical application of this model allows early identification of the severity and prognosis for patients with SAP and GNB infection and identification of patients requiring urgent management thus allowing rationalization of treatment options and improvements in clinical outcomes.
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Affiliation(s)
| | | | | | | | | | | | - Peng Jie
- Department of Gastroenterology, Xiangya Hospital, Central South University, Changsha, China
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3
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Ríos P, Rocha C, Castro W, Vidal M, Canal E, Bernal M, Reynolds ND, Tilley DH, Simons MP. Extensively drug-resistant (XDR) Pseudomonas aeruginosa identified in Lima, Peru co-expressing a VIM-2 metallo-β-lactamase, OXA-1 β-lactamase and GES-1 extended-spectrum β-lactamase. JMM Case Rep 2018; 5:e005154. [PMID: 30275958 PMCID: PMC6159545 DOI: 10.1099/jmmcr.0.005154] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Accepted: 05/23/2018] [Indexed: 11/18/2022] Open
Abstract
Introduction Pseudomonas aeruginosa has the ability to acquire plasmids and other mobile genetic elements that confer resistance to antibiotics. Bacterial genes encoding different β-lactamases (bla), such as metallo-β-lactamases (MBLs) and extended-spectrum β-lactamases (ESBL), can confer resistance to multiple classes of β-lactam antibiotics. Case presentation An 83 year old female was admitted in 2012 to the Peruvian Naval Hospital, Centro Médico Naval 'Cirujano Mayor Santiago Távara' (CEMENA), in Lima, Peru. A midstream urine sample was collected and sent to the local CEMENA laboratory for routine urine culture. P. aeruginosa was isolated and initial antibiotic susceptibility testing showed it to be sensitive to imipenem. The clinicians started a course of meropenem, but the patient did not improve. After 5 days, a second urine culture was performed and a P. aeruginosa was isolated again, but this time the strain showed resistance to imipenem. The treatment course was changed to fosfomycin and the patient improved. Phenotypic and molecular laboratory testing to characterize the antibiotic resistance were performed, demonstrating the presence of both MBL and ESBL genes. Conclusion To our knowledge, this is the first report of a P. aeruginosa XDR clinical isolate that co-expresses an MBL (VIM-2), OXA-1 beta-lactamase and the ESBL (GES-1) in Peru. It is also the first report of a VIM carbapenemase in Peru.
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Affiliation(s)
- Paul Ríos
- U.S. Naval Medical Research Unit No.6 (NAMRU-6), Lima, Perú
| | - Claudio Rocha
- U.S. Naval Medical Research Unit No.6 (NAMRU-6), Lima, Perú
| | - William Castro
- Centro Médico Naval "Cirujano Mayor Santiago Távara (CEMENA)", Lima, Perú
| | - Maria Vidal
- Centro Médico Naval "Cirujano Mayor Santiago Távara (CEMENA)", Lima, Perú
| | - Enrique Canal
- U.S. Naval Medical Research Unit No.6 (NAMRU-6), Lima, Perú
| | - Manuela Bernal
- U.S. Naval Medical Research Unit No.6 (NAMRU-6), Lima, Perú
| | | | | | - Mark P Simons
- U.S. Naval Medical Research Unit No.6 (NAMRU-6), Lima, Perú
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El Chakhtoura NG, Saade E, Iovleva A, Yasmin M, Wilson B, Perez F, Bonomo RA. Therapies for multidrug resistant and extensively drug-resistant non-fermenting gram-negative bacteria causing nosocomial infections: a perilous journey toward 'molecularly targeted' therapy. Expert Rev Anti Infect Ther 2018; 16:89-110. [PMID: 29310479 PMCID: PMC6093184 DOI: 10.1080/14787210.2018.1425139] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 01/04/2018] [Indexed: 12/30/2022]
Abstract
INTRODUCTION Non-fermenting Gram-negative bacilli are at the center of the antimicrobial resistance epidemic. Acinetobacter baumannii and Pseudomonas aeruginosa are both designated with a threat level to human health of 'serious' by the Centers for Disease Control and Prevention. Two other major non-fermenting Gram-negative bacilli, Stenotrophomonas maltophilia and Burkholderia cepacia complex, while not as prevalent, have devastating effects on vulnerable populations, such as those with cystic fibrosis, as well as immunosuppressed or hospitalized patients. Areas covered: In this review, we summarize the clinical impact, presentations, and mechanisms of resistance of these four major groups of non-fermenting Gram-negative bacilli. We also describe available and promising novel therapeutic options and strategies, particularly combination antibiotic strategies, with a focus on multidrug resistant variants. Expert commentary: We finally advocate for a therapeutic approach that incorporates in vitro antibiotic susceptibility testing with molecular and genotypic characterization of mechanisms of resistance, as well as pharmacokinetics and pharmacodynamics (PK/PD) parameters. The goal is to begin to formulate a precision medicine approach to antimicrobial therapy: a clinical-decision making model that integrates bacterial phenotype, genotype and patient's PK/PD to arrive at rationally-optimized combination antibiotic chemotherapy regimens tailored to individual clinical scenarios.
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Affiliation(s)
- Nadim G. El Chakhtoura
- Medicine Case Western Reserve University School of Medicine, Cleveland, Ohio
- Research Services Case Western Reserve University School of Medicine, Cleveland, Ohio
- Geriatrics Research, Education and Clinical Center, Louis Stokes Cleveland Department of Veterans Affairs Medical Center Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Elie Saade
- Medicine Case Western Reserve University School of Medicine, Cleveland, Ohio
- Research Services Case Western Reserve University School of Medicine, Cleveland, Ohio
- Geriatrics Research, Education and Clinical Center, Louis Stokes Cleveland Department of Veterans Affairs Medical Center Case Western Reserve University School of Medicine, Cleveland, Ohio
- Department of Medicine, University Hospitals Cleveland Medical Center Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Alina Iovleva
- Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Mohamad Yasmin
- Medicine Case Western Reserve University School of Medicine, Cleveland, Ohio
- Research Services Case Western Reserve University School of Medicine, Cleveland, Ohio
- Department of Medicine, University Hospitals Cleveland Medical Center Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Brigid Wilson
- Medicine Case Western Reserve University School of Medicine, Cleveland, Ohio
- Research Services Case Western Reserve University School of Medicine, Cleveland, Ohio
- Geriatrics Research, Education and Clinical Center, Louis Stokes Cleveland Department of Veterans Affairs Medical Center Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Federico Perez
- Medicine Case Western Reserve University School of Medicine, Cleveland, Ohio
- Research Services Case Western Reserve University School of Medicine, Cleveland, Ohio
- Geriatrics Research, Education and Clinical Center, Louis Stokes Cleveland Department of Veterans Affairs Medical Center Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Robert A. Bonomo
- Medicine Case Western Reserve University School of Medicine, Cleveland, Ohio
- Research Services Case Western Reserve University School of Medicine, Cleveland, Ohio
- Geriatrics Research, Education and Clinical Center, Louis Stokes Cleveland Department of Veterans Affairs Medical Center Case Western Reserve University School of Medicine, Cleveland, Ohio
- Department of Medicine, University Hospitals Cleveland Medical Center Case Western Reserve University School of Medicine, Cleveland, Ohio
- Departments of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio
- Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio
- Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, Ohio
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In vivo efficacy of humanized high dose meropenem and comparators against Pseudomonas aeruginosa isolates producing verona integron-encoded metallo-β-lactamase (VIM). Heliyon 2016; 2:e00121. [PMID: 27441293 PMCID: PMC4946293 DOI: 10.1016/j.heliyon.2016.e00121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 06/03/2016] [Accepted: 06/08/2016] [Indexed: 01/04/2023] Open
Abstract
Introduction We aimed to describe the in vivo efficacy of meropenem, in addition to cefepime and levofloxacin as comparators against VIM-producing Pseudomonas aeruginosa and compare the findings to our previous observations with Enterobacteriaceae. Methods Eight clinical P. aeruginosa isolates with meropenem MICs from 4 to 512 mg/L were studied in a murine neutropenic thigh infection model. Animals were treated with doses of the antibiotics to simulate the human exposure of meropenem 2 g q8 h 30-min infusion, cefepime 2 g q8 h 30-min infusion and levofloxacin 500 mg q24 h. After 24 hours, the animals were euthanized and efficacy was calculated as the change in thigh bacterial density (log10 CFU) relative to the starting inoculum (0 h). Results As expected, levofloxacin was ineffective against all isolates due to their resistant phenotype (8 to>64 mg/L). Cefepime also showed minimal activity against all isolates consistent with its failure to achieve pharmacodynamic target exposures due to high MICs of 32 to>512 mg/L. In the presence of low MICs (4 to 16 mg/L), the fT> MIC of meropenem was sufficiently high to result in CFU reductions. However, conflicting activity was noted for isolates with MICs = 128 mg/L that possessed the same enzymatic profile, suggesting that other mechanisms of resistance are responsible for driving CFU outcomes. No activity was noted for organisms with a meropenem MIC = 512 mg/L. Conclusion Unlike previous observations with MBL-producing Enterobacteriaceae that showed discordance between in vitro resistance and in vivo efficacy in the murine infection model, we found that the efficacy of humanized cefepime and meropenem was generally concordant with the phenotypic profile of VIM-producing P. aeruginosa.
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Kanj SS, Kanafani ZA. Current concepts in antimicrobial therapy against resistant gram-negative organisms: extended-spectrum beta-lactamase-producing Enterobacteriaceae, carbapenem-resistant Enterobacteriaceae, and multidrug-resistant Pseudomonas aeruginosa. Mayo Clin Proc 2011; 86:250-9. [PMID: 21364117 PMCID: PMC3046948 DOI: 10.4065/mcp.2010.0674] [Citation(s) in RCA: 178] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The development of antimicrobial resistance among gram-negative pathogens has been progressive and relentless. Pathogens of particular concern include extended-spectrum β-lactamase-producing Enterobacteriaceae, carbapenem-resistant Enterobacteriaceae, and multidrug-resistant Pseudomonas aeruginosa. Classic agents used to treat these pathogens have become outdated. Of the few new drugs available, many have already become targets for bacterial mechanisms of resistance. This review describes the current approach to infections due to these resistant organisms and elaborates on the available treatment options.
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Affiliation(s)
- Souha S Kanj
- Division of Infectious Diseases, American University of Beirut Medical Center, Cairo Street, PO Box 11-0236, Riad El Solh, Beirut 1107 2020, Lebanon.
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Carmeli Y, Akova M, Cornaglia G, Daikos GL, Garau J, Harbarth S, Rossolini GM, Souli M, Giamarellou H. Controlling the spread of carbapenemase-producing Gram-negatives: therapeutic approach and infection control. Clin Microbiol Infect 2010; 16:102-11. [PMID: 20085604 DOI: 10.1111/j.1469-0691.2009.03115.x] [Citation(s) in RCA: 233] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Although the rapid spread of carbapenemase-producing Gram-negatives (CPGNs) is providing the scientific community with a great deal of information about the molecular epidemiology of these enzymes and their genetic background, data on how to treat multidrug-resistant or extended drug-resistant carbapenemase-producing Enterobacteriaceae and how to contain their spread are still surprisingly limited, in spite of the rapidly increasing prevalence of these organisms and of their isolation from patients suffering from life-threatening infections. Limited clinical experience and several in vitro synergy studies seem to support the view that antibiotic combinations should be preferred to monotherapies. But, in light of the data available to date, it is currently impossible to quantify the real advantage of drug combinations in the treatment of these infections. Comprehensive clinical studies of the main therapeutic options, broken down by pathogen, enzyme and clinical syndrome, are definitely lacking and, as carbapenemases keep spreading, are urgently needed. This spread is unveiling the substantial unpreparedness of European public health structures to face this worrisome emergency, although experiences from different countries-chiefly Greece and Israel-have shown that CPGN transmission and cross-infection can cause a substantial threat to the healthcare system. This unpreparedness also affects the treatment of individual patients and infection control policies, with dramatic scarcities of both therapeutic options and infection control measures. Although correct implementation of such measures is presumably cumbersome and expensive, the huge clinical and public health problems related to CPGN transmission, alongside the current scarcity of therapeutic options, seem to fully justify this choice.
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Affiliation(s)
- Y Carmeli
- Division of Epidemiology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
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8
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Oie S, Fukui Y, Yamamoto M, Masuda Y, Kamiya A. In vitro antimicrobial effects of aztreonam, colistin, and the 3-drug combination of aztreonam, ceftazidime and amikacin on metallo-beta-lactamase-producing Pseudomonas aeruginosa. BMC Infect Dis 2009; 9:123. [PMID: 19664245 PMCID: PMC2738676 DOI: 10.1186/1471-2334-9-123] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2009] [Accepted: 08/10/2009] [Indexed: 12/03/2022] Open
Abstract
Background There are limited choice of antimicrobial agents to treat infection with metallo-β-lactamase-producing Pseudomonas aeruginosa. We evaluate the antimicrobial effects of aztreonam alone, colistin alone and the 3-drug combination of aztreonam, ceftazidime and amikacin on 23 strains of metallo-β-lactamase-producing P. aeruginosa by time-killing tests. Methods Strains used were from different hospitals in Japan and had different pulse-field gel electrophoresis patterns by restriction with SpeI. The minimum inhibitory concentrations of 11 antimicrobial agents (piperacillin, piperacillin/tazobactam, imipenem, meropenem, aztreonam, ceftazidime, amikacin, tobramycin, arbekacin, ciprofloxacin and colistin) were determined using the agar dilution test. The effects of aztreonam, colistin and the combination of aztreonam, ceftazidime and amikacin were determined by time-killing studies. Results Bacteriostatic effects after 6 hours of drug exposure were observed in 12 strains (52.2%) of 23 strains of metallo-β-lactamase-producing P. aeruginosa with 48 mg/l aztreonam, in 19 strains (82.6%) with the 3-drug combination of 16 mg/l aztreonam, 16 mg/l ceftazidime, and 4 mg/l amikacin, and in 23 strains (100%) with 2 mg/l colistin. Bactericidal effects after 6 h drug exposure were observed in 1 strain (4.3%) with 48 mg/l aztreonam, in 8 strains (30.4%) with the 3-drug combination and in all 23 strains (100%) with 2 mg/l colistin. Conclusion Evaluation of in vitro antimicrobial effects on metallo-β-lactamase-producing P. aeruginosa revealed relatively good effects of the 3-drug combination of aztreonam, ceftazidime and amikacin and marked effects of colistin.
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Affiliation(s)
- Shigeharu Oie
- Department of Pharmacy, Yamaguchi University Hospital, Ube, Japan.
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10
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Metallo-β-lactamases in Gram-negative bacteria: introducing the era of pan-resistance? Int J Antimicrob Agents 2009; 33:405.e1-7. [DOI: 10.1016/j.ijantimicag.2008.09.003] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2008] [Accepted: 09/03/2008] [Indexed: 11/22/2022]
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Corvec S, Poirel L, Espaze E, Giraudeau C, Drugeon H, Nordmann P. Long-term evolution of a nosocomial outbreak of Pseudomonas aeruginosa producing VIM-2 metallo-enzyme. J Hosp Infect 2008; 68:73-82. [PMID: 18079018 DOI: 10.1016/j.jhin.2007.10.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2007] [Accepted: 10/15/2007] [Indexed: 01/05/2023]
Abstract
From April 1996 to July 2004, an outbreak of metallo-beta-lactamase-positive (MBL) Pseudomonas aeruginosa occurred in the haematology ward at Nantes University Hospital in France. Fifty-nine patients were carriers of VIM-2-positive strains of whom 14 were infected (mostly urinary tract infections and pneumonia). Pulsed-field gel electrophoresis identified related isolates demonstrating resistance to all beta-lactams, aminoglycosides, fluoroquinolones, fosfomycin, rifampicin but not colistin. The bla(VIM-2) gene responsible for VIM-2 MBL was not plasmid-encoded but part of a novel type of class 1 integron. VIM-2-positive strains were mostly from urine samples and clinical data suggest that in the absence of therapeutic guidelines, piperacillin-tazobactam or aztreonam may be a reliable choice for treating infections with MBL-producing strains.
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Affiliation(s)
- S Corvec
- Service de Bactériologie-Virologie, INSERM U914 Emerging Resistance to Antibiotics Hôpital de Bicêtre, Assistance Publique/Hôpitaux de Paris, Faculté de Médecine Paris-Sud, K-Bicêtre, France.
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12
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Gupta V. Metallo beta lactamases in Pseudomonas aeruginosa and Acinetobacter species. Expert Opin Investig Drugs 2008; 17:131-43. [PMID: 18230049 DOI: 10.1517/13543784.17.2.131] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The multi drug resistant gram negative bacteria especially Pseudomonas aeruginosa and Acinetobacter species are on the rise. The major defense in these bacteria against beta-lactam antibiotics is production of metallo beta lactamases (MBLs) which degrade this group of antibiotics including carbapenems. Till now five main types of MBLs have been described throughout the World--IMP, VIM, SPM, GIM and SIM. A new MBL has been recently reported in P. aeruginosa from Australia--bla AIM-1. There are no standard guidelines by CLSI for detection of these enzymes in various bacteria. A number of phenotypic tests based on different beta lactam-inhibitor combinations are being evaluated and used for routine testing. Regarding the treatment options--colistin, various antibiotic combinations and a few novel antibiotics are being tried and evaluated. Prevention is based on age old practices of strict infection control and judicious use of antibiotics.
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Affiliation(s)
- Varsha Gupta
- Government Medical College and Hospital, Department of Microbiology, Sector 32, Chandigarh-160030, India.
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Poirel L, Pitout JD, Nordmann P. Carbapenemases: molecular diversity and clinical consequences. Future Microbiol 2007; 2:501-12. [PMID: 17927473 DOI: 10.2217/17460913.2.5.501] [Citation(s) in RCA: 219] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Carbapenemases are beta-lactamases that hydrolyze most beta-lactams including carbapenems. Carbapenemases are classified in four molecular classes; those belonging to class A are the chromosomally-encoded and clavulanic acid-inhibited IMI, NMC-A and SME, identified in Enterobacter cloacae and Serratia marcescens; the plasmid-encoded KPC enzymes identified in Enterobacteriaceae (and rarely in Pseudomonas aeruginosa); and the GES-type enzymes identified in Enterobacteriaceae and P. aeruginosa. The class B enzymes are the most clinically-significant carbapenemases; they are metallo-beta-lactamases, mostly of the IMP and the VIM series. They have been reported worldwide and their genes are plasmid- and integron-located, hydrolyzing all beta-lactams with the exception of aztreonam. One single plasmid-mediated AmpC beta-lactamase, CMY-10, identified in an Enterobacter aerogenes isolate, has been shown to be a cephaslosporinase with some carbapenemase properties. Finally, the class D carbapenemases are being increasingly reported, mostly in Acinetobacter baumannii, and they compromise the efficacy of imipenem and meropenem significantly.
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Affiliation(s)
- Laurent Poirel
- Université Paris XI, Service de Bactériologie-Virologie, Hôpital de Bicêtre, Assistance Punblique/Hôpitaux de Paris, Faculté de Médecine Paris-Sud, 94275 K.-Bicêtre, France.
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Huang YT, Chang SC, Lauderdale TL, Yang AJ, Wang JT. Molecular epidemiology of carbapenem-resistant Pseudomonas aeruginosa carrying metallo-β-lactamase genes in Taiwan. Diagn Microbiol Infect Dis 2007; 59:211-6. [PMID: 17521840 DOI: 10.1016/j.diagmicrobio.2007.01.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2006] [Revised: 01/08/2007] [Accepted: 01/14/2007] [Indexed: 11/15/2022]
Abstract
Seventy-two isolates of carbapenem-resistant Pseudomonas aeruginosa (CRPA) collected through the Taiwan Surveillance of Antimicrobial Resistance (TSAR) program in 2000 and 2002 were studied for carriage of metallo-beta-lactamase (MBL), integrase genes, and integrons. Epidemiologic relatedness was determined using pulsed-field gel electrophoresis. The prevalence of the MBL genes among CRPA was 36.0% (9 of 25) in TSAR II and 17.0% (8/47) in TSAR III, with prevalence in surveyed hospitals being 19.1% (4/21, TSAR II) and 23.1% (6 of 26, TSAR III). The bla(VIM-3) was detected in 15 of the 17 MBL-positive isolates; the remainder possessed bla(VIM-2). The bla(IMP) was not evident. Class 1 integron was detected in all MBL-positive isolates; amplicon DNA sequences containing the bla(VIM-3) regions were all identical. All MBL-positive isolates remained susceptible to colistin. Molecular typing revealed a predominant strain that comprised 14 of the isolates among the various surveyed hospitals.
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Affiliation(s)
- Yu-Tsung Huang
- Department of Internal Medicine, National Taiwan University College of Medicine, National Taiwan University Hospital, Taipei 100, Taiwan
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15
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Espedido BA, Thomas LC, Iredell JR. Metallo-beta-lactamase or extended-spectrum beta-lactamase: a wolf in sheep's clothing. J Clin Microbiol 2007; 45:2034-6. [PMID: 17409217 PMCID: PMC1933081 DOI: 10.1128/jcm.02538-06] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Diagnostic algorithms in commonly used automated bacterial identification systems fail to reliably identify a metallo-beta-lactamase in the Enterobacteriaceae. Misidentification as an extended-spectrum beta-lactamase may result in inappropriate dismissal of drugs such as aztreonam in favor of carbapenems, which may in turn select for a highly carabapenem resistant phenotype.
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Affiliation(s)
- Björn A Espedido
- Centre for Infectious Diseases and Microbiology, University of Sydney, Westmead Hospital, Westmead, NSW 2145, Australia
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Parkins MD, Pitout JDD, Church DL, Conly JM, Laupland KB. Treatment of infections caused by metallo-beta-lactamase-producing Pseudomonas aeruginosa in the Calgary Health Region. Clin Microbiol Infect 2007; 13:199-202. [PMID: 17328734 DOI: 10.1111/j.1469-0691.2006.01591.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This study reviewed 56 patients with significant metallo-beta-lactamase (MBL)-producing Pseudomonas aeruginosa infections between May 2002 and March 2004 to identify features associated with mortality. Immunosuppression (p 0.002), bacteraemia (p 0.08) and inadequate antimicrobial therapy (p <0.001) were associated with death. Among those patients treated with adequate therapy, the use of multiple drug treatment regimens (two or three active agents) was associated with a non-significant two-fold increase in survival (p 0.45). Further prospective studies are warranted to determine the optimal treatment of MBL-producing P. aeruginosa infections.
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Affiliation(s)
- M D Parkins
- Department of Medicine, Calgary, Alberta, Canada
| | - J D D Pitout
- Department of Pathology and Laboratory Medicine, Calgary, Alberta, Canada; Department of Microbiology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada; Division of Microbiology, Calgary Laboratory Services, Calgary, Alberta, Canada
| | - D L Church
- Department of Medicine, Calgary, Alberta, Canada; Department of Pathology and Laboratory Medicine, Calgary, Alberta, Canada; Division of Microbiology, Calgary Laboratory Services, Calgary, Alberta, Canada
| | - J M Conly
- Department of Medicine, Calgary, Alberta, Canada; Department of Pathology and Laboratory Medicine, Calgary, Alberta, Canada; Department of Microbiology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada; Centre for Anti-microbial Resistance, University of Calgary, Calgary Health Region and Calgary Laboratory Services, Calgary, Alberta, Canada
| | - K B Laupland
- Department of Medicine, Calgary, Alberta, Canada; Department of Pathology and Laboratory Medicine, Calgary, Alberta, Canada; Department of Critical Care Medicine, University of Calgary and Calgary Health Region, Calgary, Alberta, Canada; Centre for Anti-microbial Resistance, University of Calgary, Calgary Health Region and Calgary Laboratory Services, Calgary, Alberta, Canada.
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17
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Daikos GL, Panagiotakopoulou A, Tzelepi E, Loli A, Tzouvelekis LS, Miriagou V. Activity of imipenem against VIM-1 metallo-β-lactamase-producing Klebsiella pneumoniae in the murine thigh infection model. Clin Microbiol Infect 2007; 13:202-205. [PMID: 17328735 DOI: 10.1111/j.1469-0691.2006.01590.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The in-vivo activity of imipenem against VIM-1-producing Klebsiella pneumoniae (VPKP) was assessed in a thigh infection model in neutropenic mice. Animals were infected with three VPKP isolates (imipenem MICs 2, 4 and 32 mg/L, respectively) and a susceptible clinical isolate (MIC 0.125 mg/L) that did not produce any beta-lactamase with broad-spectrum activity. Bacterial density at the site of infection was determined after imipenem treatment (30 and 60 mg/kg every 2 h for 24 h). The log(10) reduction in CFU/thigh was greatest for the wild-type isolate, intermediate for the two imipenem-susceptible VPKP isolates, and lowest for the imipenem-resistant VPKP isolate. Whilst in-vivo imipenem activity appeared reduced against in-vitro susceptible VIM-1 producers compared with a VIM-1-negative control, an increased drug dosage could moderate this reduction.
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Affiliation(s)
- G L Daikos
- First Department of Propaedeutic Medicine, Medical School, University of Athens, Athens, Greece
| | - A Panagiotakopoulou
- First Department of Propaedeutic Medicine, Medical School, University of Athens, Athens, Greece
| | - E Tzelepi
- Laboratory of Bacteriology, Hellenic Pasteur Institute, Athens, Greece
| | - A Loli
- Laboratory of Bacteriology, Hellenic Pasteur Institute, Athens, Greece
| | - L S Tzouvelekis
- Department of Microbiology, Medical School, University of Athens, Athens, Greece
| | - V Miriagou
- Laboratory of Bacteriology, Hellenic Pasteur Institute, Athens, Greece.
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18
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Cornaglia G, Akova M, Amicosante G, Cantón R, Cauda R, Docquier JD, Edelstein M, Frère JM, Fuzi M, Galleni M, Giamarellou H, Gniadkowski M, Koncan R, Libisch B, Luzzaro F, Miriagou V, Navarro F, Nordmann P, Pagani L, Peixe L, Poirel L, Souli M, Tacconelli E, Vatopoulos A, Rossolini GM. Metallo-beta-lactamases as emerging resistance determinants in Gram-negative pathogens: open issues. Int J Antimicrob Agents 2007; 29:380-8. [PMID: 17223319 DOI: 10.1016/j.ijantimicag.2006.10.008] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2006] [Accepted: 10/29/2006] [Indexed: 01/14/2023]
Abstract
The rapid spread of acquired metallo-beta-lactamases (MBLs) among major Gram-negative pathogens is a matter of particular concern worldwide and primarily in Europe, one of first continents where the emergence of acquired MBLs has been reported and possibly the geographical area where the increasing diversity of these enzymes and the number of bacterial species affected are most impressive. This spread has not been paralleled by accuracy/standardisation of detection methods, completeness of epidemiological knowledge or a clear understanding of what MBL production entails in terms of clinical impact, hospital infection control and antimicrobial chemotherapy. A number of European experts in the field met to review the current knowledge on this phenomenon, to point out open issues and to reinforce and relate to one another the existing activities set forth by research institutes, scientific societies and European Union-driven networks.
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19
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Walsh TR. The emergence and implications of metallo-beta-lactamases in Gram-negative bacteria. Clin Microbiol Infect 2005; 11 Suppl 6:2-9. [PMID: 16209700 DOI: 10.1111/j.1469-0691.2005.01264.x] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The increase in Gram-negative broad-spectrum antibiotic resistance is worrisome, particularly as there are few, if any, ''pipeline'' antimicrobial agents possessing suitable activity against Pseudomonas spp. or Acinetobacter spp. The increase in resistance will be further enhanced by the acquisition of metallo-beta-lactamase (MBL) genes that can potentially confer broad-spectrum beta-lactam resistance. These genes encode enzymes that can hydrolyse all classes of beta-lactams and the activity of which cannot be neutralised by beta-lactamase inhibitors. MBL genes are often associated with aminoglycoside resistant genes and thus bacteria that possess MBL genes are often co-resistant to aminoglycosides, further compromising therapeutic regimes. Both types of genes can be found as gene cassettes carried by integrons that in turn are embedded within transposons providing a highly ambulatory genetic element. The dissemination of MBL genes is typified by the spread of blaVIM-2, believed to originate from a Portuguese patient in 1995, and is now present in over 20 counties. The increase in international travel is likely to be a contributory factor for the ascendancy of mobile MBL genes as much as the mobility among individual bacteria. Fitness, acquisition and host dependency are key areas that need to be addressed to enhance our understanding of how antibiotic resistance spreads. There is also a pressing need for new, and hopefully novel, compounds active against pan-resistant Gram-negative bacteria--a growing problem that needs to be addressed by both government and industry.
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Affiliation(s)
- T R Walsh
- Department of Pathology and Microbiology, School of Medical Sciences, University of Bristol, Bristol, UK.
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20
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Peleg AY, Franklin C, Bell JM, Spelman DW. Dissemination of the metallo-beta-lactamase gene blaIMP-4 among gram-negative pathogens in a clinical setting in Australia. Clin Infect Dis 2005; 41:1549-56. [PMID: 16267725 DOI: 10.1086/497831] [Citation(s) in RCA: 138] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2005] [Accepted: 07/29/2005] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND The clinical utility of carbapenems is under threat because of the emergence of acquired metallo-beta-lactamase (MBL) genes. We describe the first outbreak in Australia of infection and/or colonization with gram-negative pathogens carrying the MBL gene blaIMP-4. METHODS MBL-producing organisms were identified using susceptibility data in conjunction with MBL screening methods. PCR and sequence analysis were performed to characterize the resistance gene and identify the presence of integrons. DNA profiles were determined by ribotyping. Clinical and epidemiological data were prospectively collected from January-July 2004. RESULTS A total of 19 isolates were recovered from 16 patients: Serratia marcescens (10 isolates), Klebsiella pneumoniae (4 isolates), Pseudomonas aeruginosa (3 isolates), Escherichia coli (1 isolate), and Enterobacter cloacae (1 isolate). Isolates were resistant to most beta-lactams except aztreonam, and variable resistance to carbapenems was observed (MIC range, 2 to >8 mg/L). PCR and sequence analysis identified the blaIMP-4 gene and a class 1 integrase (IntI1) in all isolates. Of the 16 patients, 12 (75%) had infection; 5 had septicemia, 5 had ventilator-associated pneumonia, 1 had a urinary tract infection, and 1 had a superficial central venous line infection. Six (38%) of the 16 patients died, and 5 of those 6 (31% of the group of 16) had clinical infection with an MBL-producing organism. All except 2 patients had spatio-temporal epidemiological links in the intensive care unit. All K. pneumoniae isolates were of different ribogroups, whereas the S. marcescens and P. aeruginosa isolates were predominately of the same ribogroup. CONCLUSIONS MBL-producing gram-negative organisms have now emerged in Australia. The resistance gene, blaIMP-4, appears highly mobile; this outbreak involved 5 different gram-negative genera from patients with close epidemiological links.
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Affiliation(s)
- Anton Y Peleg
- Infectious Diseases and Microbiology Department, The Alfred Hospital, Melbourne, Australia.
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21
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Lolans K, Queenan AM, Bush K, Sahud A, Quinn JP. First nosocomial outbreak of Pseudomonas aeruginosa producing an integron-borne metallo-beta-lactamase (VIM-2) in the United States. Antimicrob Agents Chemother 2005; 49:3538-40. [PMID: 16048978 PMCID: PMC1196250 DOI: 10.1128/aac.49.8.3538-3540.2005] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Carbapenemases are rare in the United States. This is the first report of a United States nosocomial outbreak of pan-resistant Pseudomonas aeruginosa infections due to an integron-borne metallo-beta-lactamase, VIM-2. This emergence of carbapenemases on mobile genetic elements in the United States warrants surveillance.
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Affiliation(s)
- K Lolans
- John H. Stroger, Jr. Hospital, Rush University, Chicago, Illinois 60612, USA
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22
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Guerin F, Henegar C, Spiridon G, Launay O, Salmon-Ceron D, Poyart C. Bacterial prostatitis due to Pseudomonas aeruginosa harbouring the blaVIM-2 metallo-{beta}-lactamase gene from Saudi Arabia. J Antimicrob Chemother 2005; 56:601-2. [PMID: 16087655 DOI: 10.1093/jac/dki280] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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23
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Walsh TR, Toleman MA, Poirel L, Nordmann P. Metallo-beta-lactamases: the quiet before the storm? Clin Microbiol Rev 2005; 18:306-25. [PMID: 15831827 PMCID: PMC1082798 DOI: 10.1128/cmr.18.2.306-325.2005] [Citation(s) in RCA: 997] [Impact Index Per Article: 52.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The ascendancy of metallo-beta-lactamases within the clinical sector, while not ubiquitous, has nonetheless been dramatic; some reports indicate that nearly 30% of imipenem-resistant Pseudomonas aeruginosa strains possess a metallo-beta-lactamase. Acquisition of a metallo-beta-lactamase gene will invariably mediate broad-spectrum beta-lactam resistance in P. aeruginosa, but the level of in vitro resistance in Acinetobacter spp. and Enterobacteriaceae is less dependable. Their clinical significance is further embellished by their ability to hydrolyze all beta-lactams and by the fact that there is currently no clinical inhibitor, nor is there likely to be for the foreseeable future. The genes encoding metallo-beta-lactamases are often procured by class 1 (sometimes class 3) integrons, which, in turn, are embedded in transposons, resulting in a highly transmissible genetic apparatus. Moreover, other gene cassettes within the integrons often confer resistance to aminoglycosides, precluding their use as an alternative treatment. Thus far, the metallo-beta-lactamases encoded on transferable genes include IMP, VIM, SPM, and GIM and have been reported from 28 countries. Their rapid dissemination is worrisome and necessitates the implementation of not just surveillance studies but also metallo-beta-lactamase inhibitor studies securing the longevity of important anti-infectives.
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Affiliation(s)
- Timothy R Walsh
- Department of Pathology and Microbiology, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, United Kingdom.
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24
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Kimura S, Alba J, Shiroto K, Sano R, Niki Y, Maesaki S, Akizawa K, Kaku M, Watanuki Y, Ishii Y, Yamaguchi K. Clonal diversity of metallo-beta-lactamase-possessing Pseudomonas aeruginosa in geographically diverse regions of Japan. J Clin Microbiol 2005; 43:458-61. [PMID: 15635015 PMCID: PMC540103 DOI: 10.1128/jcm.43.1.458-461.2005] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The aim of this study was to determine the distribution of metallo-beta-lactamase-producing Pseudomonas aeruginosa in Japan and to investigate the molecular characteristics of resistance gene cassettes including the gene encoding this enzyme. A total of 594 nonduplicate strains of P. aeruginosa isolated from 60 hospitals throughout Japan in 2002 were evaluated. This study indicated that although the prevalence of imipenem-resistant P. aeruginosa has not increased compared to that found in previous studies, clonal distribution of the same strain across Japan is evident.
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Affiliation(s)
- Soichiro Kimura
- Department of Microbiology, Toho University School of Medicine, 5-21-16 Omori-nishi, Ota-ku, Tokyo 1438540, Japan
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25
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Nishio H, Komatsu M, Shibata N, Shimakawa K, Sueyoshi N, Ura T, Satoh K, Toyokawa M, Nakamura T, Wada Y, Orita T, Kofuku T, Yamasaki K, Sakamoto M, Kinoshita S, Aihara M, Arakawa Y. Metallo-beta-lactamase-producing gram-negative bacilli: laboratory-based surveillance in cooperation with 13 clinical laboratories in the Kinki region of Japan. J Clin Microbiol 2005; 42:5256-63. [PMID: 15528723 PMCID: PMC525181 DOI: 10.1128/jcm.42.11.5256-5263.2004] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A total of 19,753 strains of gram-negative rods collected during two 6-month periods (October 2000 to March 2001 and November 2001 to April 2002) from 13 clinical laboratories in the Kinki region of Japan were investigated for the production of metallo-beta-lactamases (MBLs). MBLs were detected in 96 (0.5%) of the 19,753 isolates by the broth microdilution method, the 2-mercaptopropionic acid inhibition test, and PCR and DNA sequencing analyses. MBL-positive isolates were detected in 9 of 13 laboratories, with the rate of detection ranging between 0 and 2.6% for each laboratory. Forty-four of 1,429 (3.1%) Serratia marcescens, 22 of 6,198 (0.4%) Pseudomonas aeruginosa, 21 of 1,108 (1.9%) Acinetobacter spp., 4 of 544 (0.7%) Citrobacter freundii, 3 of 127 (2.4%) Providencia rettgeri, 1 of 434 (0.2%) Morganella morganii, and 1 of 1,483 (0.1%) Enterobacter cloacae isolates were positive for MBLs. Of these 96 MBL-positive strains, 87 (90.6%), 7 (7.3%), and 2 (2.1%) isolates carried the genes for IMP-1-group MBLs, IMP-2-group MBLs, and VIM-2-group MBLs, respectively. The class 1 integrase gene, intI1, was detected in all MBL-positive strains, and the aac (6')-Ib gene was detected in 37 (38.5%) isolates. Strains with identical PCR fingerprint profiles in a random amplified polymorphic DNA pattern analysis were isolated successively from five separate hospitals, suggesting the nosocomial spread of the organism in each hospital. In conclusion, many species of MBL-positive gram-negative rods are distributed widely in different hospitals in the Kinki region of Japan. The present findings should be considered during the development of policies and strategies to prevent the emergence and further spread of MBL-producing bacteria.
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Affiliation(s)
- Hisaaki Nishio
- Clinical Laboratory, Shiga Medical Center for Adults, Moriyama, Shiga 524-8524, Japan.
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Ozkiriş A, Evereklioglu C, Kontaş O, Oner AO, Erkiliç K. Determination of Nontoxic Concentrations of Piperacillin/Tazobactam for Intravitreal Application. Ophthalmic Res 2004; 36:139-44. [PMID: 15103204 DOI: 10.1159/000077326] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2003] [Accepted: 01/09/2004] [Indexed: 11/19/2022]
Abstract
BACKGROUND To investigate the highest nontoxic intravitreal dose of piperacillin/tazobactam in rabbits. MATERIAL AND METHODS Forty New Zealand white albino rabbits were used in this study. The rabbits were divided into four equal groups (10 rabbits in each) and the right eyes were treated with 0.1 ml intravitreal injections of 1,000 microg piperacillin/tazobactam in group 1, 500 microg in group 2, 250 microg in group 3, and 100 microg in group 4. The left eyes served as controls and were injected with 0.1 ml of saline solution. Ganzfeld electroretinogram (ERG) was performed on all eyes before and after 4 weeks of intravitreal injections. Then, the rabbits were killed and the eyes were enucleated for histopathological evaluation of the retina. Retinal sections were evaluated by morphometric analyses on cell counts of ganglion cell layer and thickness of the various retinal layers. RESULTS Baseline ERGs were similar among the groups (p > 0.05). After 4 weeks of injection, there were a reduction of the b-wave amplitude and extension of the b-wave implicit time in photopic and scotopic ERGs in group 1 and group 2 when compared with controls (for each, p < 0.001). Intravitreal injection of 100 and 250 microg piperacillin/tazobactam did not cause any deterioration of the b-wave of ERGs throughout the follow-up period of 4 weeks (for each, p > 0.05). After morphometric analysis of retinal sections in all groups, there were no statistically significant differences in the mean number of surviving ganglion cells, thickness of the whole retina and the inner plexiform layer compared with controls (p > 0.05). CONCLUSION 250 microg/0.1 ml piperacillin/tazobactam is the highest nontoxic dose to the normal retinas of adult albino rabbits as intravitreal injection. Piperacillin/tazobactam may be a new, potentially important drug in the treatment of endophthalmitis as it has a broad antimicrobial spectrum.
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Affiliation(s)
- Abdullah Ozkiriş
- Department of Ophthalmology, Erciyes University Medical Faculty, Kayseri, Turkey.
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Toraman ZA, Yakupogullari Y, Kizirgil A. Detection of metallo β-lactamase production and antibiotic resistance with E-test method in pseudomonas, acinetobacter and klebsiella strains, in Turkey. J Infect Chemother 2004; 10:257-61. [PMID: 16163458 DOI: 10.1007/s10156-004-0333-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2004] [Accepted: 07/12/2004] [Indexed: 10/26/2022]
Abstract
The metallo beta-lactamase (MBL) mediated resistance patterns remain unknown in most countries. We aimed to investigate the existence and antimicrobial resistance of MBL-producing strains among carbapenem-resistant gram-negative bacteria that were isolated from nosocomial infections in patients in an university hospital in Turkey. Fifteen of 52 Pseudomonas aeruginosa strains (29%), 5 of 24 Acinetobacter baumanii strains (21%), and 2 of 2 Klebsiella pneumoniae strains (100%) were found to be metallo enzyme producers, with the Etest MBL technique. The in vitro antibiotic susceptibility of the MBL-positive organisms was investigated by the Etest method. Of the ten drugs tested, isepamicin was the most active agent against the MBL-producing strains. Overall, the rank order of activity of the ten antibiotics, in terms of the percentages of susceptible strains, was: isepamicin, 73%; ciprofloxacin, 64%; amikacin, 59%; aztreonam, 18%; tobramycin, 18%; meropenem, 14%; cefoperazone-sulbactam, 5%; piperacillin-tazobactam, 0%; ticarcillin-clavulanate, 0%; and cefepim, 0%. The meropenem minimum inhibitory concentrations (MICs) of the metallo enzyme-producing and nonproducing carbapenem-resistant strains were compared, and the MBL-producers were found to have higher meropenem MICs than the nonMBL-producing carbapenem-resistant strains. Early preventive measures should be taken against MBL-producing nosocomial pathogens that are associated with wide spread and high antimicrobial resistance.
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Affiliation(s)
- Zulal Asci Toraman
- Firat University Medical Center Microbiology and Clinical Microbiology Department, 23100, Elazig, Turkey
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Abstract
PURPOSE OF REVIEW Recent articles of clinical interest on Pseudomonas aeruginosa respiratory tract infections including CAP, nosocomially-acquired pneumonia, particularly in the ventilated patient, and chronic infections in cystic fibrosis patients are reviewed. RECENT FINDINGS The growing importance of P. aeruginosa as an etiologic agent of CAP, the occurrence of CAP in previously healthy adults and its high prevalence as an etiologic agent of late VAP are stressed in recent studies. The effect of antibiotics on the recovery of bacteria in respiratory samples of patients with VAP can be marked and as early as 12 h after administration of antimicrobials certain organisms are no longer cultivable; in contrast, P. aeruginosa can still be recovered even after 48 h of adequate therapy. Type III secretory proteins are recognized as important virulent factors in P. aeruginosa. This phenotype predicts a worse outcome in patients with VAP. Fluoroquinolones have a major role in the emergence of multiply resistant P. aeruginosa in patients with VAP. Pharmacokinetic/pharmacodynamic parameters of antimicrobials with antipseudomonal activity are gaining importance as a means of optimization of antibiotic therapy. In CF, the knowledge of the pharmacokinetics and bioavailability of inhaled tobramycin and its long term beneficial effect in lung function are important developments in this area. SUMMARY P. aeruginosa continues to be a serious problem worldwide as a cause of respiratory tract infections in selected populations. Microbiologic diagnosis remains difficult and plagued with pitfalls. The application of modern PK/PD concepts should help to optimize antibiotic therapy of this increasingly difficult to treat infection, particularly at the respiratory tract level and with an increasing prevalence of resistance to all antipseudomonal agents. Inhaled antibiotics, particularly tobramycin, are increasingly used for the prevention and treatment of P. aeruginosa infection in CF patients.
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Affiliation(s)
- Javier Garau
- Department of Medicine, Hospital Mutua de Terrassa, University of Barcelona, Spain.
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