Antibiotic resistance, virulence factors, and phylogenetic groups of Escherichia coli isolated from hospital wastewater: A case study in the west of Iran

The appropriate management of hospital wastewater is an essential process to prevent the spread of pathogenic strains of bacteria including Escherichia coli in this study, the antibiotic resistance, virulence characteristics, and phylogenetic diversity of E. coli isolated from the raw and treated hospital wastewater in a general hospital in the west of Iran were evaluated.

E. coli isolates were recovered and identified using culture and biochemical tests. Sixty isolates were used and antimicrobial resistance, virulence genes, antibiotic-resistant genes (ARGs), and phylogeny groups of isolates were determined using polymerase chain reaction (PCR) assay. The antibiotic resistance was tested using disk diffusion.

The antibiotic susceptibility testing indicated that the resistance to co-trimoxazole was the most common, followed by ceftriaxone, amikacin, and gentamicin. Multi-drug resistance (MDR) was observed in 90% of raw and 96.66% of treated sewage isolates. The phylogeny groups B1 and A were the most common groups among isolates of raw and treated sewage, respectively. The most common virulence genes detected were sfa, papC, and fyuA; while pic and sepA genes were not found in the isolates. The most common ARGs were blaTEM (in 90% isolates of raw and 92.5% of treated sewage) and blaCTX-M (in 60% isolates of raw and 77.5% of treated sewage). The blaSHV-5 gene was not detected among isolates.

The results highlight the potential of hospital wastewater as a source for spreading the virulent and multi drug-resistant strains of E. coli.