The Research Center for Gastroenterology and Liver Diseases, Shaheed Beheshti University, MC, Tehran, Iran.
Int J Antimicrob Agents. 2011 Apr;37(4):360-4. doi: 10.1016/j.ijantimicag.2010.12.013. Epub 2011 Mar 3.
The aim of the current study was to detect mutations in the gyrA gene of quinolone-resistant Salmonella spp. isolates recovered in Tehran, Iran. Between April 2008 and September 2009, 174 Salmonella spp. were collected and assayed for quinolone resistance and detection of gyrA mutations. Isolates identified as Salmonella enterica were tested for susceptibility by the disk diffusion method. Polymerase chain reaction (PCR) amplification and sequencing of the gyrA gene segment encoding the quinolone resistance-determining region (QRDR) were performed for the nalidixic acid-resistant isolates. Amongst the 174 recovered Salmonella spp. isolates, 89 were resistant to nalidixic acid, of which 9 were resistant to enrofloxacin; 10 isolates had reduced susceptibility to nalidixic acid. None of the isolates were resistant to ciprofloxacin, but a single isolate showed reduced susceptibility. Twelve types of amino acid replacement were found in the QRDR region of GyrA, namely the previously described substitutions in positions 83 and 87 as well as five new substitutions Leu41-Pro, Arg47-Ser, Ser111-Thr, Ala118-Thr and Asp147-Gly. Double substitutions in both positions 83 and 87 were not identified. A Gly133-Glu substitution was identified in a single S. enterica serotype Typhi isolate.
本研究旨在检测 2008 年 4 月至 2009 年 9 月在伊朗德黑兰分离的耐喹诺酮类药物沙门氏菌中 gyrA 基因突变。共收集并检测了 174 株沙门氏菌，以确定其对喹诺酮类药物的耐药性和 gyrA 基因突变。经纸片扩散法药敏试验鉴定为肠沙门氏菌的菌株，对其进行 nalidixic acid 药敏试验。对 nalidixic acid 耐药的菌株进行 gyrA 基因编码喹诺酮耐药决定区（QRDR）的聚合酶链反应（PCR）扩增和测序。在所分离的 174 株沙门氏菌中，有 89 株对 nalidixic acid 耐药，其中 9 株对恩诺沙星耐药；10 株对 nalidixic acid 的敏感性降低。没有分离株对环丙沙星耐药，但有 1 株对环丙沙星的敏感性降低。gyrA 的 QRDR 区发现了 12 种氨基酸取代，包括先前在 83 和 87 位描述的取代，以及 5 种新的取代：Leu41-Pro、Arg47-Ser、Ser111-Thr、Ala118-Thr 和 Asp147-Gly。没有发现 83 和 87 位的双取代。在 1 株 Typhi 血清型沙门氏菌中发现了 Gly133-Glu 取代。
