Metallo-beta-lactamase producing Escherichia coli and Klebsiella pneumoniae: A rising threat for hospitalized children

To determine the frequency of metallo-beta-lactamase (MBL) producing E.coli and Klebsiella pneumoniae, better phenotypic techniques for MBL detection and choices of treatment available for such cases. This study was conducted in The Children's Hospital, Lahore during March, 2013 and February, 2014. A total number of 17,651 samples including blood, urine, CSF, pus and catheter tips from suspected cases of bacterial infections were processed and test organisms were identified using standardized microbiological techniques. MBL phenotypic identification was performed by Modified Hodge Test, Double Disc Synergy Test and Combined Disc Test. Carbapenem resistance was observed in 134/1168 (11.47%) strains which comprised of 89 (67.4%) Klebsiella pneumoniae and 45 (32.6%) E.coli. All of these carbapenem resistant isolates were found to be carbapenemase producers (CP) by MHT test. Among these CP strains, MBL was detected in 131/134 (97.8%) isolates both by CDT and DDST including 87 (66.4%) Klebsiella pneumoniae and 44 (33.6%) E.coli. Majority of these organisms were resistant to most of the antibiotics used in the study. The isolates showed good susceptibility to colistin (90.1%), chloramphenicol (60.3%) and fosfomycin(31%). Isolation of such a high number of MBL producers is a serious threat for hospitalized paediatric patients.