Emergence of TEM, SHV, and CTX-M-Extended Spectrum β-Lactamases and Class 1 Integron AmongEnterobacter cloacaeIsolates Collected from Hospitals of Tehran and Qazvin, Iran

Abstract

Extended-spectrum β-lactamase (ESBL) production is an important resistance mechanism among clinical isolates of Enterobacter cloacae. TEM, SHV, and CTX-M are the most common ESBL genotypes among Enterobacter spp. The main aims of this study were to determine the antimicrobial susceptibility pattern and to detect ESBL-encoding genes as well as intI1 genes. One hundred twenty isolates of E. cloacae were collected from hospitals of Tehran and Qazvin, Iran. The isolates were identified by standard laboratory methods and API 20E strips. ESBL screening was performed by the combined disk method. PCR and sequencing were conducted for detection of ESBL-encoding genes as well as intI1 genes. Clonal relatedness of ESBL-producing isolates was assessed by the enterobacterial repetitive intergenic consensus (ERIC)-PCR method. Of 120 isolates, 57 (47.5%) were characterized as multidrug resistant among those 48 (84.2%) isolates carried class 1 integron. Fifty-three (44.2%) isolates were found to be ESBL producers, in which bla(CTX-M-15) (60.4%) was the most common gene followed by bla(TEM-1) (32.1%), bla(TEM-169) (13.2%), and bla(SHV-12) (7.5%) either alone or in combination. Forty-four of the 53 (83.01%) ESBL-producing isolates were genetically unrelated. For the first time, this study describes the emergence of TEM-169, SHV-12, and CTX-M-15 ESBL genotypes in E. cloacae isolates in Iran.

High prevalence of plasmid-mediated quinolone resistance determinants in Enterobacter cloacae isolated from hospitals of the Qazvin, Alborz, and Tehran provinces, Iran

“…This may indicate that the rate of PMQR is increasing among enterobacteria. In a previous study, we reported that 53 (44.2%) of the E. cloacae isolates studied were extended-spectrum β-lactamase (ESBL) producers (36) . Taken together, these data suggest that inappropriate and extensive use of broad-spectrum antibiotics has resulted in the emergence of resistant isolates in our hospital settings.…”

Clonal relation and antimicrobial resistance pattern of extended-spectrum β-lactamase- and AmpC β-lactamase-producing Enterobacter spp. isolated from different clinical samples in Tehran, Iran

“…Enterobacter species may cause severe nosocomial infections, including bloodstream, respiratory tract, and central nervous system infections as well as endocarditis 1,2 . Nosocomial infections caused by these microorganisms have been associated with high rates of mortality and morbidity 1 .…”

“…Nosocomial infections caused by these microorganisms have been associated with high rates of mortality and morbidity 1 . Enterobacter cloacae and Enterobacter aerogenes are the most common species isolated from clinical samples 3 .…”

“…Another important virulence factor is the type III secretion system encoded by FliI that delivers a variety of effectors directly into the cytosol of host as well as aerobactin, encoded by the iutA, described as a virulence factor related to iron acquisition from host-binding proteins 6,7 . β-lactam antibiotics, especially third-generation cephalosporins and carbapenems, are used to treat infections cause by several species of Enterobacter [1][2][3] . β-lactamase enzymes, including extended-spectrum β-lactamases (ESBLs) and AmpC, are involved in the mechanism underlying resistance to β-lactam antibiotics in Enterobacter spp [1][2][3] .…”

“…β-lactam antibiotics, especially third-generation cephalosporins and carbapenems, are used to treat infections cause by several species of Enterobacter [1][2][3] . β-lactamase enzymes, including extended-spectrum β-lactamases (ESBLs) and AmpC, are involved in the mechanism underlying resistance to β-lactam antibiotics in Enterobacter spp [1][2][3] . ESBLs are often encoded by genes located on large plasmids that also carry genes for resistance to other antimicrobial agents such as aminoglycosides and fluoroquinolones 1 .…”