BACKGROUND: Metallo-beta-lactamase (MBL) producing Pseudomonas aeruginosa has emerged as a threat to hospital infection control, due to its multi-drug resistance, especially in intensive care units (ICUs). AIMS: This study was carried out to detect MBL producing P. aeruginosa isolates from medical and surgical ICUs, to compare and evaluate different phenotypic methods currently in use and to determine antibiograms. METHOD: A prospective study was undertaken to detect MBLs in P. aeruginosa isolates obtained from various clinical samples. A total of 49 strains were recovered from patients admitted in inpatient wards and ICUs, and screened for imipenem resistance by Kirby Bauer disk diffusion method. Detection of MBLs was further done by imipenem-EDTA disk synergy test and combined disk test. RESULTS: Out of 49 isolates, 11 isolates (22.4 per cent) were imipenem resistant. All 11 imipenem resistant P. aeruginosa strains, when further tested, were positive for MBL production by combined disk test, but, only eight showed positive results by imipenem-EDTA disk synergy test. CONCLUSION: MBL production was the main resistance mechanism in the 11 carbapenem resistant P. aeruginosa isolates collected, with multidrug resistance associating significantly with MBL production in P. aeruginosa from our institution.
BACKGROUND: Metallo-beta-lactamase (MBL) producing Pseudomonas aeruginosa has emerged as a threat to hospital infection control, due to its multi-drug resistance, especially in intensive care units (ICUs). AIMS: This study was carried out to detect MBL producing P. aeruginosa isolates from medical and surgical ICUs, to compare and evaluate different phenotypic methods currently in use and to determine antibiograms. METHOD: A prospective study was undertaken to detect MBLs in P. aeruginosa isolates obtained from various clinical samples. A total of 49 strains were recovered from patients admitted in inpatient wards and ICUs, and screened for imipenem resistance by Kirby Bauer disk diffusion method. Detection of MBLs was further done by imipenem-EDTA disk synergy test and combined disk test. RESULTS: Out of 49 isolates, 11 isolates (22.4 per cent) were imipenem resistant. All 11 imipenem resistant P. aeruginosa strains, when further tested, were positive for MBL production by combined disk test, but, only eight showed positive results by imipenem-EDTA disk synergy test. CONCLUSION:MBL production was the main resistance mechanism in the 11 carbapenem resistant P. aeruginosa isolates collected, with multidrug resistance associating significantly with MBL production in P. aeruginosa from our institution.
Entities:
Keywords:
Metallo-beta-lactamases; Multidrug resistance; Pseudomonas aeruginosa; infection control
Authors: Alexandre R Marra; Carlos Alberto P Pereira; Ana Cristina Gales; Liana C Menezes; Ruy Guilherme R Cal; José Marconi A de Souza; Michael B Edmond; Cynthia Faro; Sérgio B Wey Journal: Antimicrob Agents Chemother Date: 2006-01 Impact factor: 5.191