Prompt detection of metallo-β-lactamase (MBL) producing isolates is necessary to prevent their dissemination. Frequency of MBLs producing strains among multidrug resistant (MDR) Acinetobacter species and Pseudomonas aeruginosa was evaluated in critical care patients using imipenem-EDTA disk method. One hundred MDR Acinetobacter spp. and 42 Pseudomonas aeruginosa were checked for MBL production, from January to June 2001. MBL was produced by 96.6 % of imipenem-resistant Acinetobacter isolates, whereas 100% imipenem-resistant Pseudomonas aeroginosa isolates were MBL producers. Carbapenem resistance in MDR Acinetobacter spp. and Pseudomonas aeruginosa isolates in this study was due to MBLs. This calls for strict infection control measures to prevent further dissemination. Key words: Acinetobacter spp, metallo-β-lactamase, Pseudomonas aeruginosaCarbapenem group of antibiotics play a vital role in the management of hospital-acquired gram negative infections, because of their broad spectrum activity and stability to hydrolysis by most of the β-lactamases, including extended spectrum β-lactamases (ESBLs). Nosocomial outbreaks of carbapenem-resistant Pseudomonas aeruginosa and Acinetobacter spp. due to metallo-β-lactamases (MBLs) production have been reported from different regions. [1][2][3] The emergence of these MBLs in gram negative bacilli is becoming a therapeutic challenge as these enzymes possess high hydrolytic activity that leads to degradation of higher generation cephalosporins. Moreover, the treatment alternatives are unavailable, or expensive/toxic with poor outcome.[4] Plasmid mediated MBL genes spread rapidly to other species of gram negative bacilli; [5] therefore rapid detection of metallo-ß-lactamases production is necessary to modify therapy and to initiate effective infection control to prevent their dissemination. To date there has been one report from Pakistan suggesting presence of MBL producing isolate.[6] There is however need for a systematic study to assess the extent of this form of resistance amongst our isolates. The purpose of this study was to evaluate the metallo-ß-lactamase (MBL) production among multidrug resistant (MDR) Acinetobacter spp. and Pseudomonas aeruginosa, isolated from clinical specimens of intensive care unit patients. Materials and MethodsThis study was conducted in the clinical microbiology laboratory of The Aga Khan University Hospital, Karachi, Pakistan. One hundred MDR clinical isolates of Acinetobacter species and 42 Pseudomonas aeruginosa were studied for MBL production. These organisms were isolated from respiratory secretions, wound swabs, urine and blood culture specimens of intensive care unit patients, admitted from January to April 2001. A multidrug resistant isolate was deÞ ned as resistance to two or more drugs or drug classes of therapeutic relevance. [7] All the isolates of Pseudomonas aeruginosa were characterised to species level using standard procedures. Similarly, Acinetobacter isolates were characterised to the genus level using these proced...

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Fluoroquinolone and macrolide antibiotics are generally considered as first-line drugs for the treatment of severe campylobacteriosis. This study was conducted to analyse the trend of erythromycin and ofloxacin resistance among Campylobacter spp. isolated from stool specimens over a period of 15 years (1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007) at The Aga Khan University clinical laboratory in Karachi, Pakistan. A total of 83 396 stool specimens were processed, with a 14% isolation rate for enteric pathogens. The isolation rate of Campylobacter spp. was low during 1992-93 (6%-13%), peaked in 1996 (46%), then ranged from 20% to 40%. We report a rising trend in ofloxacin resistance, re-emergence of erythromycin resistance and indications of co-resistance to both drugs in clinical isolates of Campylobacter spp.

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