Detection of AmpC beta-lactamase in clinical isolates of Escherichia coli among children

ABSTRACT

The production of AmpC beta-lactamases is one of the common mechanisms of beta-lactam drugs resistance. AmpC beta-lactamases produce resistance to various clinically important cephalosporins. The purpose of this study was to determine the frequency of AmpC beta-lactamase producing Escherichia coli and its occurrence in different clinical samples. This cross sectional observational study was conducted during April 2011 to March 2012 in the Microbiology Department of The Children's Hospital and Institute of Child Health, Lahore. A total number of 20,257 pathological samples like blood, cerebrospinal fluid [CSF], urine, pus, endotracheal tube [ETT], pleural fluid, sputum and urinary catheters were analyzed during the study period. E. coli were identified using API 20E system and resistance to cefoxitin was used as a screening test followed by disk potentiation as confirmatory test for AmpC beta-lactamases. E. coli were isolated in 670 samples out of which 85 [12.6%] were AmpC beta-lactamase producers. The gender distribution of patients with AmpC beta-lactamase producing E. coli was 52 [61.2%] in males and 33 [38.8%] in females. The occurrence rate of AmpC beta-lactamase producing E. coli in clinical samples was highest in blood 45 [52.9%].The present study shows moderately high frequency of AmpC beta-lactamase producing E. coli which may increase morbidity and mortality among children. Earlier detection of AmpC beta-lactamases will decrease the morbidity rate of AmpC beta-lactamase producing E. coli infection.