Evaluation of different phenotypic diffusion methods in the identification of extended spectrum beta lactamase producing uropathogenic

Abstract

: The study was aimed to identify the occurrence of extended spectrum of Beta lactamases (ESBLs), to compare different phenotypic methods used for the confirmation and to evaluate the antibiotic resistance pattern in ESBL producing uropathogenic : The strains were isolated from urine and the isolates resistance to at least one of the three representative cephalosporins (cefotaxime, cefpodoxime and ceftazidime) was tested for ESBL production by Double disc synergy test (DDST), Inhibitory potentiated disc diffusion (IPDD) test and quantitative E-strip method.: Of 120strains isolated, 62(51.6%) were resistant to at least one of the three cephalosporins and 28 (45.1%) were positive for ESBL by IPDD and E-strip test. However, 9 (14.5%) strains were positive by DDST method. Among third generation cephalosporins, cefpodoxime was (45.8%) better screening indicator followed by ceftazidime (40.0%) and cefotaxime (37.5%). Most of the ESBL producers (97.3%) were resistant to three or more drugs, compared to (51.2%) non-ESBL producers. : The acceptable method for detection of ESBL producing were IPDD and E-strip tests compared to DDST with better sensitivity (100%), specificity (95.8%) and positive predictive value (96.5%). ESBL producers showed significantly (p<0.05) higher resistance to tobramycin, amoxyclav and amikacin compared to non ESBL producers.