Detection Of GyrA And ParC Mutations In Quinolone-Resistant Clinical Isolates Of Ureaplasma Urealyticum

Objective: To study the mutation of gyrA and parC gene in clinical isolates of Ureaplasma urealyticum (Uu) resistance to quinolones.Methods: With both solution culture and solid culture, 15 isolates of Uu with different degree resistance to quinolones, including ciprofloxacin, ofloxacin, and sparfloxacin, were selected. After DNA extraction, their gyrA and parC gene were amplified by polymerase chain reaction (PCR) and sequenced. Then the sequences of their gyrA and parC gene were compared with standard strains(Ureaplasma parvum serovar 3 str. ATCC 700970) by blast software.Results: Point mutation of parC gene, i.e. the cytosine in site 248 was mutated into thymine, resulted in alteration of the serin in site 83 into leucine, was observed in 3 of the 5 ciprofloxacin-resistant isolates, whereas no mutation was detected in the other two. Point mutation of parC gene was observed in all the 10 double- or triple-quinonone resistant isolates. Of all the 10 isolates, the same mutation were observed in 9 isolates, and the other isolate showed that the cytosine in site 298 of parC gene was mutated into thymine, but no amino acid alteration was observed. Point mutation of gyrA gene was observed in all these 10 double- or triple-quinonone resistant isolates, the cytosine in site 336 was mutated into amidopurine, resulted in atleration of the aspartic acid in site 112 into glutamine.Conclusion: Among the 15 strains of Uu resistance to quinolones,13 have mutations in QRDR,the mutations of gyrA or parC gene may have association with the resistance of Uu to quinolones. Furthermore, the concurrent mutations of both gyrA and parC gene may have associated with the multiple resistance of Uu to quinolones.