Farahi Rosetta Moshirian, Ali Ahya Abdi, Gharavi Sara
Department of Microbiology, Alzahra University, Tehran, Iran.
Department of Biotechnology, Alzahra University, Tehran, Iran.
Iran J Microbiol. 2018 Aug;10(4):242-249.
, a major cause of several infectious diseases, has become a hazardous resistant pathogen. One of the factors contributing to quinolone resistance in is mutations occurring in and genes encoding the A subunits of type II and IV topoisomerases, respectively, in quinolone resistance determining regions (QRDR) of the bacterial chromosome.
Thirty seven isolates from patients with burn wounds and 20 isolates from blood, urine and sputum specimen were collected. Minimum Inhibitory Concentrations (MICs) of ciprofloxacin were determined by agar diffusion assay. Subsequently, QRDRs regions of and were amplified from resistant isolates and were assessed for mutations involved in ciprofloxacin resistance after sequencing.
Nine isolates with MIC≥8 μg/ml had a mutation in (Thr83→Ile). Amongst these, seven isolates also had a mutation in (Ser87→ Leu or Trp) indicating that the prevalent mutation in is Thr83Ile and Ser87Leu/Trp in . No single mutation was observed.
It seems that mutations in are concomitant with mutations in which might lead to high-level ciprofloxacin resistance in isolates from patients with burn wounds and urinary tract infections.
作为多种传染病的主要病因，已成为一种具有危害的耐药病原体。导致喹诺酮耐药的因素之一是细菌染色体喹诺酮耐药决定区（QRDR）中分别编码II型和IV型拓扑异构酶A亚基的gyrA和parC基因发生突变。
收集了37株烧伤患者伤口分离株以及20株血液、尿液和痰液标本分离株。采用琼脂扩散法测定环丙沙星的最低抑菌浓度（MIC）。随后，从耐药分离株中扩增gyrA和parC的QRDR区域，并在测序后评估与环丙沙星耐药相关的突变。
9株MIC≥8μg/ml的分离株gyrA发生了Thr83→Ile突变。其中，7株分离株parC也发生了Ser87→Leu或Trp突变，表明gyrA中常见的突变是Thr83Ile，parC中是Ser87Leu/Trp。未观察到单一的parC突变。
似乎gyrA突变与parC突变同时存在，这可能导致烧伤患者和尿路感染患者分离株对环丙沙星产生高水平耐药。
