prevalence of klebsiella pneumoniae encoding genes for ctx-m-1, tem-1 and shv-1 extended-spectrum beta lactamases (esbl) enzymes in clinical specimens

background infections caused by gram negative bacteria, producing extended-spectrum β-lactamase (esbl), including klebsiella pneumoniae are increasing all over the world with high morbidity and mortality. objectives the aim of this study was to determine the prevalence of k. pneumoniae encoding the ctx-m, tem-1 and shv-1 esbl enzymes genes, isolated from clinical specimens. materials and methods a total of 500 entrobacteriaceae isolates were collected and identified using traditional culturing and biochemical tests. antibiotic susceptibility testing was performed by disc-diffusion method according to the clsi guideline. screening of esbls was undertaken using combination disc method. pcr technique was used to detect shv-1, tem-1 and ctx-m-1 genes according to the standard protocol. results fifty five (11%) out of 500 tested entrobacteriaceae isolates were identified as k. pneumoniae possessing 26 (47.27%) esbl positives amongst them. esbls positives showed the highest resistance to amoxicillin-clavulanic acid (100%), followed by amoxicillin (97.89%) and ampicillin (96.36%). imipenem and meropenem showed the highest antibacterial activity against esbl producing k. pneumoniae. based on the results of pcr, the prevalence of shv-1, tem-1 and ctx-m-1 genes among esbls-positive isolates was 12 (46.15%), 9 (34.61%), and 7 (26.92%) respectively. tem-1 and shv-1 were seen in four isolates (15.38%) simultaneously. conclusions in conclusion, the rate of esbl-producing k. pneumoniae was 47.27% in the present study, representing their commonness in our institute resistance to many classes of antibiotic, resulting in limited treatment options. since the management of infections caused by these organisms is difficult, it is important to control such strains closely in order to prevent and reduce their spread.