Prevalence of plasmid-mediated quinolone resistance and 16S rRNA methylase genes among Escherichia coli clinical isolates in a hospital in Saudi Arabia.

The plasmid-mediated quinolone resistance (PMQR) and 16S ribosomal RNA (rRNA) methylase genes can lead to high-level bacterial resistance to various antibiotics, including quinolones and aminoglycosides. This study determined the prevalence of PMQR and 16S rRNA methylase determinants in clinical Escherichia coli. Non-duplicate E. coli resistant to quinolones (nalidixic acid, ciprofloxacin, or norfloxacin) and/or aminoglycosides (amikacin or gentamicin) were collected from patients at King Abdullah Hospital, Bisha, Saudi Arabia. A multiplex PCR was performed to identify the targeted genes. Out of 107 screened isolates, 44 (41%) were found to carry resistance genes, individually or in combination, including 41 PMQR and 14 16S rRNA methylase. The qnrS gene had the highest prevalence (23.4%) among PMQR, followed by aac(6')-Ib (16.8%). Of the 14 identified 16S rRNA methylase, 8 were rmtB and 6 were armA. Out of 44 positive isolates, 72.7% carried only one resistance gene, 25% had co-existing resistance genes, with qnrS and rmtB or aac(6)-Ib and armA being the most common pairs. A single isolate was carried three genes (qnrS, aac(6')-Ib and rmtB). As antibiotic resistance continues to become more prevalent, there is a need for extensive research to identify the genetic determinants of resistance and to develop new antibiotic therapies.