Herrero Ana, Rodicio M Rosario, Echeita M Aurora, Mendoza M Carmen
Departamento de Biología Funcional, Area de Microbiología, Facultad de Medicina, University of Oviedo, C/Julián Clavería no 6, E-33006 Oviedo, Spain.
Int J Med Microbiol. 2008 Apr;298(3-4):253-61. doi: 10.1016/j.ijmm.2007.04.008. Epub 2007 Jun 26.
The epidemiological impact in Spain of an emerging group of multidrug-resistant Salmonella enterica serotype Typhimurium, characterized by the presence of virulence-resistance hybrid plasmids (termed pUO-StVR) that are related to the S. Typhimurium virulence plasmid pSLT, was evaluated. Adscription to the group was based on detection of the bla(OXA-1) gene (encoding ampicillin resistance) by PCR, and identification of a pUO-StVR plasmid through hybridization with specific probes for virulence (spvC) and resistance (bla(OXA-1)) genes. In this way, 57 out of 134 ampicillin-resistant clinical isolates of S. Typhimurium, collected over 2002-2004 in 21 Spanish cities, were assigned to the group, which can be already regarded as endemic. Most isolates (>89%) shared the following features: (i) resistance to ampicillin, chloramphenicol, streptomycin/spectinomycin, sulfonamides, and tetracycline, encoded by bla(OXA-1)-catA1-aadA1-sul1-tet(B); (ii) a class 1 integron (InH) with the bla(OXA-1)-aadA1 gene cassettes within its variable region of ca. 2000bp; (iii) the spvC, rck, samA, oriT, traT, traX, repA (RepFIIA), and parA/B genes (but not rsk and pefABCD) of pSLT; (iv) a hybrid plasmid of ca. 125kb, termed pUO-StVR2, where the resistance and virulence genes are located. However, intra-group diversity was also detected, since a total of four resistance phenotypes, five resistance genotypes, two integron profiles, five plasmid variants (pUO-StVR2, 4-7, differing in size, restriction profile and/or resistance pattern), 15 XbaI-BlnI combined macrorestriction profiles, and five phage types were identified. Each hybrid plasmid was revealed as a distinctive BlnI band, through hybridization with pUO-StVR2. The genetic markers used, together with the knowledge generated in the present study, could be applied to epidemiological surveillance of S. Typhimurium pUO-StVR worldwide.
对西班牙出现的一组多重耐药性肠炎沙门氏菌鼠伤寒血清型的流行病学影响进行了评估，该血清型的特征是存在与鼠伤寒沙门氏菌毒力质粒pSLT相关的毒力-抗性杂交质粒（称为pUO-StVR）。根据通过聚合酶链反应（PCR）检测bla(OXA-1)基因（编码氨苄青霉素抗性）以及通过与毒力（spvC）和抗性（bla(OXA-1)）基因的特异性探针杂交来鉴定pUO-StVR质粒，将菌株归为该组。通过这种方式，在2002年至2004年期间于西班牙21个城市收集的134株氨苄青霉素抗性鼠伤寒沙门氏菌临床分离株中，有57株被归为该组，该组已可被视为地方流行组。大多数分离株（>89%）具有以下共同特征：（i）对氨苄青霉素、氯霉素、链霉素/壮观霉素、磺胺类药物和四环素耐药，由bla(OXA-1)-catA1-aadA1-sul1-tet(B)编码；（ii）一个1类整合子（InH），在其约2000bp的可变区内含有bla(OXA-1)-aadA1基因盒；（iii）pSLT的spvC、rck、samA、oriT、traT、traX、repA（RepFIIA）和parA/B基因（但不包括rsk和pefABCD）；（iv）一个约125kb的杂交质粒，称为pUO-StVR2，抗性和毒力基因位于其上。然而，也检测到组内多样性，因为总共鉴定出四种耐药表型、五种耐药基因型、两种整合子图谱、五种质粒变体（pUO-StVR2、4 - 7，在大小、限制性图谱和/或耐药模式上有所不同）、15种XbaI - BlnI联合宏观限制性图谱以及五种噬菌体类型。通过与pUO-StVR2杂交，每种杂交质粒都显示为一条独特的BlnI带。所使用的遗传标记以及本研究中产生的知识可应用于全球鼠伤寒沙门氏菌pUO-StVR的流行病学监测。
