Prevalence of Metallo-β-lactamase Producing Non-fermentative Pseudomonas Species from Clinical Isolates in Dhaka, Bangladesh.

Antimicrobial drug resistance, a global concern, has been increasing unpredictably in microorganism causing human infections specially among Gram negative non-fermenting Pseudomonas spp. Carbapenems, a beta lactam antibiotics, are the most potent and effective drug usually kept reserved for treating the multi-drug resistant Psedomonas spp and other infections caused by organisms producing Extended Spectrum Beta Lactamase (ESBL) and AmpC. Clinical utility of carbapenem will reduce when resistant bacteria evolve due to production of carbapenem hydrolyzing Metallo-β-lactamase (MBL) which confers high-level resistance to all beta-lactam antibiotics except aztreonam. The various reports on the prevalence of MBLs are available from many countries but few from Bangladesh. We investigated the prevalence of MBL production in these Pseudomonads obtained from clinical sources in an uraban setting in Dhaka, Bangladesh. A total of 29,136 specimens were processed for culture from January 2011 and December 2015 from non duplicated patients attending diagnostic unit of icddr,b from different settings of Bangladesh. The specimens included urine 14,323; blood 11,378; other body fluid 2,487; sputum 535 and tracheal aspirate 413. All specimens were processed for culture following standard bacteriological methods and the Pseudomonas spp were identified following defined standard biochemical procedures. Metallo-β-lactamase (MBL) was determined by EDTA disk synergy (EDS) test. Antimicrobial susceptibility test was performed by disk diffusion method and susceptibility pattern was interpreted and reported following Clinical Laboratory Standard Institute (CLSI) guideline. From 29,136 specimens a total of 2,340(8%) were isolated and identified as Pseudomonas spp. Of the identified Pseudomonas spp, 238(57.6%) were from tracheal aspirate, 216(40.4%) from sputum, 902(36.7%) from other body fluids, 463(4.1%) from blood and 521(3.6%) from urine samples. From 2,340 Pseudomonas spp, by selective sampling, imipenem-meropenem resistant and intermediate susceptible 100 strains were tested for MBL production and 92 were found positive. Tracheal aspirate showed 38%, other body fluids 30%, Urine 17%, sputum 4% and blood 3% MBL production respectively. Irrespective of the sources of specimens, Pseudomonas spp showed 71% resistance to cefixime, 70% to ceftriaxone, 64% to gentamicin, 56% to piperecillin+tazobactam, 50% to ciprofloxacin, 49% to amikacin, 46% to netilmicin, 45% to ceftazidime, 30% to meropenem, 26% to imipenem and 19% to polymyxin B. As multi-drug resistant Pseudomonas showed high level of (92%) MBL production, so MBL detection testing facility may be a useful battery to determine MDR producing Pseudomonas from clinical isolates.