Molecular Investigation of Quinolone Resistance of Quinolone Resistance-Determining Region in Streptococcus pneumoniae Strains Isolated from Iran Using Polymerase Chain Reaction-Restriction Fragment Length Polymorphism Method.
OBJECTIVE
The resistance of Streptococcus pneumoniae to the recently available antibiotic treatment has been a growing problem. The aim of the study was to determine the quinolone-resistant strains and detect the presence of mutations in the quinolone resistance-determining regions of the gyrA, parE, and parC genes.


METHODS
In this study, for the first time in Iran, the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was used to investigate the presence of mutations at quinolone resistance-determining regions of topoisomerase IV and DNA gyrase on 82 S. pneumoniae strains, among them 45 clinical samples were from patients and 37 from healthy carriers (control group).


RESULTS
In clinical samples, 34 (75.56%) strains contained mutations in the parC gene, 31 (68.89%) carried mutations in the gyrA gene, and 14 (31.11%) had parE gene mutations. Antibiotic susceptibility test was performed using the CLSI (Clinical and Laboratory Standards Institute) criteria on three different generations of quinolone family, with nalidixic acid (82.22%) showing the highest resistance and levofloxacin (42.22%) the least resistance.


CONCLUSIONS
Results indicated that there is a significant correlation between quinolone resistance development and mutations in the parE gene as well as in the parC and gyrA genes.
Department of Microbiology, Islamic Azad University, Jahrom Branch, Jahrom, Iran.
Mohammad
M
Kargar
Department of Microbiology, Islamic Azad University, Jahrom Branch, Jahrom, Iran.
Fataneh
F
Moein Jahromi
Biotechnology Research Center, Islamic Azad University, Shahrekord Branch, Shahrekord, Iran.
Abbas
A
Doosti
Nanotechnology Research center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Somayeh
S
Handali
Streptococcus pneumoniae; gyrA; parC; parE; polymerase chain reaction–restriction fragment length polymorphism; quinolones