Fecal Carriage of Extended-Spectrum β-Lactamases and pAmpC Producing Enterobacterales in an Iranian Community: Prevalence, Risk Factors, Molecular Epidemiology, and Antibiotic Resistance.

Abstract

This study aimed to determine the prevalence and risk factors associated with intestinal carriage of extended-spectrum β-lactamases producing Enterobacterales (ESBL-PE) and plasmid-mediated AmpC β-lactamase producing Enterobacterales (AmpC-PE) in healthy children in Ardabil, Iran. A total of 305 fecal samples were collected. Isolates underwent antimicrobial susceptibility testing, phenotypic and genotypic identification of β-lactamase production, and epidemiologic molecular typing. In total, 21.5%, 1.5%, and 1.2% of volunteers were extended-spectrum β-lactamase (ESBL)-, AmpC-, and simultaneous ESBL/AmpC-PE carriers, respectively. Escherichia coli was the predominant ESBL producing bacterium (70.2%) found in ESBL-PE colonized subjects. Beyond ESBL positive isolates, bla CTX-M group genes were the most common type (75.6%) and bla TEM (non-bla TEM-1 and non- bla TEM-2) were in the second place (25.6%). Among bla CTX-M genes, bla CTX-M-1 (55.3%) and bla CTX-M-15 (55.3%) were the most predominant types with equal prevalence. Some isolates were multi-enzyme producers. bla CIT and bla DHA genes were common AmpC type enzyme encoding genes found in AmpC-PE isolates. Most isolates produced both enzymes at the same time. The number of students in the classes was statistically associated with ESBL-PE intestinal carriage (p < 0.05). Moreover, 46 (65.7%), 3 (60%), 4 (100%), and 98 (39.8%) ESBL-, AmpC-, ESBL/AmpC, and non-ESBL/AmpC-PE isolates were multidrug-resistant, respectively. Overall, regardless of β-lactam antibiotics, 62% and 59.5% of isolates were resistant to co-trimoxazole and tetracycline, respectively. The majority of ESBL producing E. coli isolates (69.2%) belonged to phylogroup A. According to Enterobacterial repetitive intergenic consensus polymerase chain reaction, there was no clonal relatedness between isolates. This study showed a high rate of multi-resistant ESBL-PE intestinal carriage among healthy individuals in Iran.