ABSTRACT
Background: This study attempted to elucidate the spectrum of sexually transmitted infections in a tertiary care centre in North India and to assess the antimicrobial resistance in Neisseria gonorrhoeae. Materials and Methods: Antimicrobial resistance pattern of N. gonorrhoeae was determined by the standard techniques. Genotypic detection of gyrA, parC and blaTEM genes was also carried out. The results of gyrA gene by polymerase chain reaction were confirmed by DNA sequencing. Results: N. gonorrhoea was identified in 10 (4.98%) patients, and antimicrobial sensitivity was performed in seven patients. All the seven patients tested were quinolone-resistant N. gonorrhoeae (QRNG), 5/7 were penicillinase-producing N. gonorrhoeae, 1/7 was chromosomally mediated penicillin-resistant N. gonorrhoeae and 3/7 were tetracycline-resistant N. gonorrhoeae. Minimal inhibitory concentration (MIC) by E-test was performed in five strains, and we observed that MIC90 for ciprofloxacin was ?4 ?g/ml, for penicillin was ?6 ?g/ml and for tetracycline was 12 ?g/ml, which clearly brackets them as resistant isolates. The presence of TEM gene was confirmed genotypically in six out of seven cases. In all seven cases, gyrA and parC were observed, thus confirming their QRNG status. Conclusion: Alarming increase in the resistance to commonly used antimicrobials for gonorrhoea in our study, especially of fluoroquinolones, is a clarion call for the urgent need for prudence in prescribing them. Observing the rampant resistance exhibited by N. gonorrhoeae, it is clear that the day is not far when it will acquire a superbug status and become intractable to treatment by the available antibiotics.
ABSTRACT
Aim To study gyrA and parC mutations of clinical Pseudomonas aeruginosa strains. Methods MIC values of 55 clinical P.aeruginosa isolates were determined by agar dilution test and 1 sensitive strain and 8 resistant strains were selected with standard sensitive strain ATCC27853 as control, the quinolone determining region (QRDR) of the gyrA and parC genes were amplified by PCR, the lengths of PCR products were 351 bp and 397 bp. The gyrA PCR products(351 bp) were digested with enzyme sacⅡ. The gyrA and parC gene were sequenced. Results In this study, gyrA genes of all resistant strains had an ACC to ATC mutation in codon 83, leading to the amino acid substitution of an isoleucine for a threonine, and three high level resistant strains also showed a GAC to GGC mutation in codon 87, leading to the substitution of a glycine for an aspartic acid. In addition, four resistant strains also had an TCG to TTG mutation in codon 87 of parC gene, leading to the amino acid substitution of a serine for a leucine. The strains with both gyrA and parC mutations were two to sixteen times more resistant than the strains which had only gyrA mutations. At the same time, a silent mutation (CAC to CAT) in codon 132 of gyrA gene and a silent mutation(GCT to GCG) in codon 115 of parC gene occured, which did not lead to amino acid change. Conclusion The mutations of 83 and 87 codons of gyrA and the mutatations of 87 codon of parC gene were related to fluroquinolone resistance, and the mutations of the 83 codon of gyrA gene were more important.
ABSTRACT
OBJECTIVE To study the correlation between mutations of gyrA and parC genes and ciprofloxacin-(resistant) clinical isolates of Acinetobacter baumannii from Chengdu.METHODS The genes of gyrA and parC DNA in 28 ciprofloxacin-resistant and 2 ciprofloxacin-susceptible isolates of A.baumannii were amplified by PCR and then analyzed by restriction fragment length polymorphism(PCR-RFLP) and DNA sequencing.(RESULTS) Hinf Ⅰ digestion of the gyrA gene products of susceptible isolates(generated) two fragments,but resistant isolates(generated) one fragment.The parC gene products generated 2 fragments.DNA sequencing of 5 resistant isolates revealed mutations in gyrA gene that resulted in amino acid substitutions: Ser83→Leu and Ala88→Thr,especially,Ser83 point mutation accounting for the disappearance of sequence of Hinf Ⅰ.There was not any mutation in(gyrA) of 1 susceptible isolate;the substitution of Ser108→Ile in parC(gene) of 1 susceptible and 1 resistant isolates were identified,the remaining four isolates had more nosense mutations.CONCLUSIONS Compared with parC gene mutations,(gyrA) gene mutations of A.baumannii appears to be the main molecular mechanism responsible for ciprofloxacin resistance.The high-level ciprofloxacin resistance in A.baumannii probably needs a variety of mutations.