Prevalence of the qnrB, qnrA and blaTEM genes in temperate bacteriophages of Escherichia coli isolated from wastewater and sewer water from slaughterhouses in the State of Mexico

Antibiotic resistance genes (ARG) have been described mainly in bacteria, but are known to occur in temperate phages. Prevalence of the qnrB, qnrA and bla(TEM) genes was identified in Escherichia coli strains and temperate phages by lytic cycle induction. From a total of 48 samples collected from drinking water, wastewater and sewer water in slaughterhouses in the State of Mexico, Mexico, 37 contained E. coli isolates. Resistance was highest to tetracycline (32/37; 86.4 %), followed by trimethoprim-sulfamethoxazole (19/37; 51.3 %) and ampicillin and nalidixic acid (18/37; 48.6 %). Prevalence of the bla(TEM) gene was 37.8 % in the bacterial isolates and 3.5 % in the phage isolates. The bacterial isolates contained 8.1 % qnrA and 29.7 % qnrB genes, while the phage isolates contained 2.7 and 24.3 %, respectively. Presence of ARG in the bacterial isolates was linked to phage DNA, highlighting the significant role it plays in the spread of ARG in the studied slaughterhouses. Understanding the mechanisms of antimicrobial resistance will contribute to developing effective control measures.