Plasmid-mediated quinolone resistance (PMQR) and mutations in the topoisomerase genes of Salmonella enterica strains from Brazil
Plasmid-mediated quinolone resistance (PMQR) and mutations in the topoisomerase genes of Salmonella enterica strains from Brazil
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DOI：
10.1590/s1517-83822013000200046
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发表时间：
2013-01-01
影响因子：
2.2
通讯作者：
Royo, Gloria
中科院分区：
文献类型：
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作者：
Ferrari, Rafaela;Galiana, Antonio;Royo, Gloria
本研究的目的是鉴定沙门氏菌gyrA、gyrB、parc和pare基因的喹诺酮类耐药决定源区(QRDR)的突变，并确定是否存在qnR变异或aac(6‘)-Ib-cr变异。在巴西与世隔绝。共检出沙门氏菌126株。对来自疫情(n=114)和家禽(n=12)来源的菌株进行了评估。112株(88.8%)耐药，29株(23.01%)对环丙沙星敏感性降低。已鉴定的突变仅限于密码子中GyrA基因的QRDR替换丝氨酸83、天冬氨酸87和丙氨酸131。在QRDR中，对NAL的敏感性似乎是区分突变株和非突变株的一个很好的表型指标，但gyrA的双重突变并不会导致对环丙沙星的耐药性。在1株肠炎链球菌流行株和1株禽源Corvallis链霉菌中分别检测到qnrA1和qnrB19基因。尽管巴西此前曾检测到qnr基因，但这是首次在沙门氏菌中检测到qnr基因，也是国内首次检测到qnrB19基因。该结果提示应继续监测喹诺酮类耐药决定因素，以最大限度地减少沙门氏菌的出现和选择。对喹诺酮类药物敏感性降低或耐药的菌株。
The objective of this study was to identify mutations in the Quinolone Resistance Determining sources Regions (QRDR) of the gyrA, gyrB, parC, and parE genes and to determine if any of the qnr variants or the aac(6')-Ib-cr variant were present in strains of Salmonella spp. isolated in Brazil. A total of 126 Salmonella spp. strains from epidemic (n = 114) and poultry (n = 12) origin were evaluated. One hundred and twelve strains (88.8%) were resistant to nalidixic acid (NAL) and 29 (23.01%) showed a reduced susceptibility to ciprofloxacin (Cip). The mutations identified were substitutions limited to the QRDR of the gyrA gene in the codons for Serine 83, Aspartate 87 and Alanine 131. The sensitivity to NAL seems to be a good phenotypic indication of distinguishing mutated and non-mutated strains in the QRDR, however the double mutation in gyrA did not cause resistance to ciprofloxacin. The qnrA1 and qnrB19 genes were detected, respectively, in one epidemic strain of S. Enteritidis and one strain of S. Corvallis of poultry origin. Despite previous detection of qnr genes in Brazil, this is the first report of qnr gene detection in Salmonella, and also the first detection of qnrB19 gene in this country. The results alert for the continuous monitoring of quinolone resistance determinants in order to minimize the emergence and selection of Salmonella spp. strains showing reduced susceptibility or resistance to quinolones.