Prevalence of TEM Beta-Lactamases and Determination of MIC of four Different Classes of Antibiotics in Klebsiella pneumonaia Clinical Isolates

Background & Aims: Organisms producing TEM-β-lactamase are emerging around the world as a source of resistance to β-lactam antibiotics such as three generation cephalosporins. In this study, we used a polymerase chain reaction (PCR) to identify genes TEM for Extended-spectrum β-lactamase (ESBLs) producing clinical isolates of Klebsiella pneumonia from hospitals of Boroujerd/ Iran. Method: A total of 100 K. pneumoniae isolates were collected from different hospitals in Boroujerd. Phenotypic screening and confirmatory tests for ESBL detection were performed according to Clinical and Laboratory Standards Institute (CLSI) guidelines. Minimum inhibitory concentration (MIC) of azteronam, amikacin, ciprofloxacin and meropenem were determined by micro broth dilution method. All of the ESBL-producing isolates were examined for the presence of TEMgene by PCR method. Results: Primary phenotypic tests revealed that 41% (n=31) of K. pneumonia isolates produced ESBLs. In confirmatory tests using clavulanic acid, ESBL production was confirmed in 100% of isolates with a primary positive test. Among the ESBL producing K. pneumoniae, 31 isolates were positive for TEM gene. The study showed excellent susceptibility among the strains to meropenem and amikacin. Low susceptibility to ciprofloxacin and the lowest susceptibility to azteronam were observed. Conclusion: ESBLs producing isolates can be combined with resistance to other classes of antibiotics such as aminoglycosides. Also, meropenem can be a good treatment options to control infections caused by ESBLs producing organisms.