Fecal colonization, phenotypic and genotypic characterization of ESBL-producing Escherichia coli isolates in transplant patients in Shiraz Nemazee and Abu Ali Sina Hospitals

The current work aimed at investigating the intestinal carriage of Extended-spectrum β-lactamases (ESBLs)-producing Escherichia coli (ESBL-EC), determining the clonal relatedness, phylogroups and adhesion factors among ESBL-EC strains obtained from rectal swabs from transplant patients in a tertiary care teaching hospital. This cross-sectional study was conducted during February to August of 2020 in Shiraz, Iran. Rectal swabs (RS) were randomly collected from transplant patients. The combination disk was used as a phenotypic method to detect ESBL-producing strains. PCR was performed for the genotypic detection of ESBL and adhesion factors, classify the phylogenetic group of each ESBL-EC strain and major sequence types (STs). A total of 118 E. coli isolates were collected from rectal swab from hospitalized transplant patients. Among them, 37.9% (49/118) patients were colonized with ESBL isolates. The majority of the isolates were from kidney transplant patients (29/49, 59.2%). Overall, of the 49 isolates identified as ESBL-producers, 42 (85.7%) isolates harbored the bla CTX-M gene. The detection of the different pathotypes from 49 ESBL-producer isolates showed that the most prevalent pathotype was STEC (32.7%). According to the multiplex PCR results, most (42.8%) of the ESBL-producer isolates belonged to phylogroup B 2. The most frequent sequence type (ST) among E. coli isolates was ST131 (26.5%). Our study revealed high production of ESBL-encoding genes with bla CTX-M as the most predominant gene, moreover, it revealed high intestinal colonization with ST131 ESBL-EC. Therefore, to reduce and prevent the spread of ESBL-EC, early detection of fecal carriage at the beginning of admission in clinical settings especially in immunocompromised patients is recommended.