Molecular Characterization of blaCTX-M, blaTEM and blaSHV Beta Lactamases Produced by Uropathogens

Background: This prospective study was carried out to look for the frequency of isolation of Extended spectrum b lactamase (ESBL) producing bacteria from urine samples and study their susceptibility pattern. The detection of ESBL genes responsible for their resistance was done by Polymerase chain reaction (PCR).

Methods: The study was carried out over a period of one year from January 2016 to December 2016. Urine specimens from patients were processed as per standard protocol. Antimicrobial susceptibility testing was performed by disk diffusion method as per CLSI guidelines 2016.

Urine isolates obtained were screened for ESBL, by cefotaxime, ceftazidime disk and confirmation was made by Double disk diffusion test method. The detection of ESBL genes responsible for their resistance was done by Polymerase chain reaction (PCR) for blaCTX-M, blaTEM and blaSHV genes.

Results: Prevalence of ESBL producing uropathogens were found to be 20.47% with most common organism to be isolated was Escherichia coli (E. coli) followed by Klebsiella pneumoniae. Nitrofurantoin and Imipenem were the most effective antibiotic agents against urinary isolates. Most common gene responsible for ESBL production was blaCTX-M (71.42%).

Conclusion: A large number of ESBL producing strains are creating significant therapeutic problems. Therefore, monitoring of ESBL production, judicious use of antibiotics and infection control measures are necessary to avoid treatment failures in patients with Urinary Tract Infections (UTI).