Detection of amp-c beta-lactamases in urinary isolates of escherichia coli through various phenotypic methods

To determine the prevalence of Amp C beta lactamases in urinary isolates of Escherichia coli (E. coli), and to evaluate and compare different phenotypic methods for its detection in a cost effective way. Study Design: Descriptive study. Place and Duration of Study: Department of Microbiology, Combined Military Hospital Lahore Pakistan, from Jan 2016 to Jun 2016. Material and Methods: Modified Three Dimensional Test (M3DT) taken as Gold standard, Modified Hodge Test (MHT) (Cefoxitin), Nitrocephin test and three screening strategies for the detection of Amp C Beta-lactamases were tested on urinary isolates of E. coli collected during a period of 06 months. Results: Modified Hodge Test, was found to be simple, highly specific and sensitive in detecting these enzyme producers. Collectively these tests detected 45.07% of E. coli to be Amp C producers. Conclusion: Each of the three tests can be used as an acceptable phenotypic confirmatory tool when Amp C production in E. coli is suspected. (author)