Emergence of OXA-Type Extended-Spectrum β-Lactamases Among Enterobacter cloacae Isolates Collected From Hospitals of Tehran, Karaj and Qazvin, Iran

Abstract

Background: Extended-Spectrum β-Lactamases (ESBLs)-producing Enterobacter cloacae has been increasingly reported as a major clinical concern in recent years. TEM and SHV β-lactamase are the most common ESBL genotypes that are found in Enterobacteriaceae; however, there are also new families of ESBLs, including OXA-type enzymes, which are one of the most important mechanisms of resistance to oxyimino-cephalosporin antibiotics. OXA-type ESBLs are divided into five groups. Objectives: The main aim of the present study was to determine the frequency of blaOXA genes among ESBL-producing E. cloacae isolates in three distinct provinces of Iran. Patients and Methods: A total of 82 non-repetitive ESBL-producing E. cloacae isolates were collected from hospitalized patient in Qazvin, Karaj, and Tehran hospitals, Iran. The isolates were identified by standard laboratory methods and then confirmed by API 20E strips. PCR and sequencing was performed for detection of blaOXA-1, blaOXA-2, blaOXA-9, and blaOXA-10 genes. The clonal relatedness of OXA-producing isolates was assessed by enterobacterial repetitive intergenic consensus PCR (ERIC-PCR). Results: In total, 48 ESBL-producing isolates (58.5%) were positive for the blaOXA-1 gene. All blaOXA-1-producing isolates showed multidrug resistant pattern. In this study, blaOXA-2, blaOXA-9, and blaOXA-10 genes were not detected. The ERIC-PCR results showed that 42 OXAproducing isolates (77.7%) were genetically diverse with different band patterns. Conclusions: This study was the first report of the emergence of the plasmid-encoded blaOXA genes among E. cloacae isolates in Iran. These findings highlight the need to use appropriate infection control policy and rational antibiotic therapy to reduce further spread of these resistant bacteria in the studied hospitals.