Frequent Topoisomerase IV Mutations Associated with Fluoroquinolone Resistance in Ureaplasma Species.

This study aimed to investigate the role of quinolone resistance-determining regions (QRDRs) of DNA gyrase (encoded by gyrA and gyrB) and topoisomerase IV (encoded by parC and parE) associated with fluoroquinolone resistance. A total of 114 Ureaplasma spp. strains, isolated from clinical female patients with symptomatic infection, were determined for species distribution and susceptibility to four fluoroquinolones. Moreover, we analyzed the QRDRs and compared with 14 ATCC reference strains of Ureaplasma spp. serovars to identify mutations that caused antimicrobial resistance. Our study indicated that moxifloxacin was the most effective fluoroquinolone against Ureaplasma spp. (MIC range: 0.125-32 μg/mL). However, extremely high MICs were estimated to ciprofloxacin (MIC range; 1-256 μg/mL) and ofloxacin (MIC range: 0.5-128 μg/mL), followed by levofloxacin (MIC range: 0.5-64 μg/mL). Seven amino acid substitutions were discovered in GyrB, ParC, and ParE, but not in GyrA. Ser-83→Leu/Trp (C248T/G) in ParC and Arg-448→Lys (G1343A) in ParE, which were potentially responsible for fluoroquinolone resistance, were observed in 89 (77.2%) and 3 (2.6%) strains, respectively. Pro-462→Ser (C1384T), Asn-481→Ser (A1442G), and Ala-493→Val (C1478T) in GyrB and Met-105→Ile (G315T) in ParC, seemed to be neutral polymorphisms, were observed and occurred along with the amino acid change of Ser-83→Leu (C248T) in ParC. Interestingly, two novel mutations of ParC and ParE were independ...
Source: Journal of Medical Microbiology - Category: Microbiology Authors: Tags: J Med Microbiol Source Type: research