Prevalence of Extended-Spectrum β-Lactamases Among Klebsiella pneumoniae Isolated from Intensive Care Unit Patients in a Tertiary Hospital

Background: The increased prevalence of extended-spectrum -lactamases (ESBLs)-producing virulent strains possibly leads to serious outbreaks in hospitals. Objectives: The aims of the study were to detect ESBLs in Klebsiella pneumoniae isolated from patients in intensive care units (ICUs) of a hospital and to investigate their genetic relationships. Methods: A total number of 85 K. pneumoniae isolates were detected in the specimens of ICU patients in a tertiary hospital in the southwest of Tehran, Iran. Antibiotic susceptibility was determined by the disk diffusion method. The rmpA and wcaG virulence genes were detected by polymerase chain reaction (PCR). The ESBL-positive isolates were typed using multilocus variable-number tandem repeat analysis (MLVA) method. Results: Of the 85 K. pneumoniae isolates, 48 (56.5%) produced ESBLs. There were statistically significant differences in the prevalence of virulence genes based on ESBL production. The typing of the 48 ESBL-positive isolates showed a significant genetic relatedness with the identification of nine MLVA types. Conclusions: This study showed a relatively high prevalence of ESBL in K. pneumoniae isolated from ICU patients and a low diversity between these isolates. The selection of ESBL-producing clones was mainly responsible for the spread of K. pneumoniae in the ICUs.