Phenotypic and genotypic detection of extended spectrum beta lactamase Klebsiella pneumoniae isolated from intensive care units in Assiut university hospital

ABSTRACT

Extended spectrum beta lactamases producing Klebsiella pneumoniae [ESBL-KP] are an important cause of nosocomial infections in Intensive Care Units [ICUs]. We conducted a prospective study on 650 patients who were admitted to different adult ICUs at Assiut University Hospital to determine the incidence of ESBL-KP by phenotypic and genotypic methods. Phenotypic tests for ESBL were combined disc method, double disc synergy test [DDST] and E-test. Genotypic detection of ESBL bla TEM and bla SHV genes was carried out by polymerase chain reaction amplification [PCR]. The overall nosocomial infection incidence rate was 20% [130 patients]. Klebsiella pneumonia was isolated from 44 patients [34%], in which 23 isolates were found to be phenotypically ESBL producers. ESBL-KP was most frequently isolated from chest ICU [47.8%] and blood was the most frequent site of infection [8 isolates, 34%]. Based on Clinical and Laboratory Standards Institute [CLSI] screening test for ESBL, the combined disc method was the most sensitive [23/23, 100%] followed by the E-test [95.6%] and lastly the DDST [91.3%]. SHV gene was present in 8 isolates, TEM gene in 2 isolates, both SHV and TEM in 11 isolates and none of TEM or SHV in 2 isolates. Out of 950 environmental samples, Klebsiella pneumoniae was isolated from 48 samples [16.4%] in which 7 isolates [14.5%] were ESBL an genotyping revealed SHV in 4 strains, and both SHV and TEM in 3 strains