Lithuania 人群和动物源大肠杆菌分离株中三苯甲基嘧啶耐药基因的流行率。
Prevalence of trimethoprim resistance genes in Escherichia coli isolates of human and animal origin in Lithuania.
机构信息
Department of Biochemistry and Biophysics, Faculty of Natural Sciences, Vilnius University, M. K. Čiurlionio 21, LT-03101 Vilnius, Lithuania.
Veterinary Institute of Lithuania Veterinary Academy, Instituto 2, LT-56115 Kaišiadorys, Lithuania.
出版信息
J Med Microbiol. 2010 Mar;59(Pt 3):315-322. doi: 10.1099/jmm.0.015008-0. Epub 2009 Dec 10.
A total of 456 non-repetitive Escherichia coli isolates from human clinical specimens (urinary, n=134; cervix, vagina and prostate, n=52; blood, pus and wounds, n=45), healthy animals (cattle, n=45; poultry, n=20) and diseased animals (cattle, n=53; swine, n=64; poultry, n=43) obtained in Lithuania during the period 2005-2008 were studied for trimethoprim (TMP) resistance and the prevalence of dfr genes. A TMP resistance rate in the range of 18-26 % respective to the origin was found in clinical isolates, 23-40 % in isolates from diseased animals and 9-20 % in isolates from healthy animals. Of 112 TMP-resistant isolates, 103 carried at least one of the six dfrA genes (dfrA1, dfrA5, dfrA8, dfrA12, dfrA14 and dfrA17) as determined by multiplex PCR and RFLP. The dfrA1 and dfrA17 genes were found most frequently in clinical isolates (17 and 19 isolates, respectively), whilst dfrA1 and dfrA14 genes dominated in isolates of animal origin (25 and 13 isolates, respectively). The dfrA5, dfrA12 and dfrA8 genes were detected at lower frequencies. The association with class 1/class 2 integrons was confirmed for 73-100 % of dfr genes found in most groups of isolates, except for the isolates from diseased swine. In this group, the majority of dfr-positive isolates (67 %, 8/12) carried dfrA8 (6/12) or dfrA14 genes (2/12) that were not associated with integrons. Non-integron location was also confirmed for the remaining dfrA8 genes (six clinical isolates and one isolate from diseased cattle) and for dfrA14 genes (two isolates from diseased cattle and swine each). All cassette-independent dfrA14 genes were found to be located within the strA gene. This study on the prevalence and distribution of TMP resistance genes among E. coli isolates of human and animal origin in Lithuania demonstrates that dfr genes are carried most frequently as gene cassettes within class 1 and/or class 2 integrons. However, TMP resistance in some of the isolates was found to be mediated by non-integron-associated dfrA8 and dfrA14 genes, indicating the existence of alternative sources for the spread of resistance.
2005-2008 年期间，在立陶宛，从人类临床标本（尿液，n=134；宫颈、阴道和前列腺，n=52；血液、脓液和伤口，n=45）、健康动物（牛，n=45；家禽，n=20）和患病动物（牛，n=53；猪，n=64；家禽，n=43）中获得了总计 456 株非重复的大肠杆菌分离株，对其进行了甲氧苄啶（TMP）耐药性和 dfr 基因流行率研究。发现临床分离株的 TMP 耐药率在 18-26%之间，患病动物分离株的耐药率在 23-40%之间，健康动物分离株的耐药率在 9-20%之间。通过多重 PCR 和 RFLP 检测，在 112 株 TMP 耐药分离株中，有 103 株至少携带 6 种 dfrA 基因中的一种（dfrA1、dfrA5、dfrA8、dfrA12、dfrA14 和 dfrA17）。dfrA1 和 dfrA17 基因在临床分离株中最为常见（分别为 17 和 19 株），而 dfrA1 和 dfrA14 基因在动物来源的分离株中占主导地位（分别为 25 和 13 株）。dfrA5、dfrA12 和 dfrA8 基因的检出率较低。除了患病猪的分离株外，在所研究的大多数分离株组中，发现与 class 1/class 2 整合子相关的 dfr 基因的频率为 73-100%。在该组中，大多数 dfr 阳性分离株（67%，8/12）携带 dfrA8（6/12）或 dfrA14 基因（2/12），这些基因与整合子无关。还证实了剩余的 dfrA8 基因（6 株临床分离株和 1 株患病牛分离株）和 dfrA14 基因（2 株患病牛和猪分离株）的非整合子定位。所有无盒式 dfrA14 基因均位于 strA 基因内。这项关于立陶宛人类和动物源大肠杆菌分离株中 TMP 耐药基因流行率和分布的研究表明，dfr 基因最常作为 class 1 和/或 class 2 整合子中的基因盒携带。然而，一些分离株的 TMP 耐药性是由非整合子相关的 dfrA8 和 dfrA14 基因介导的，这表明存在耐药性传播的替代来源。
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