Virulence genes and antibiotic resistance of Enterococcus faecium isolated from yaks in Qinghai-Tibet Plateau, China
ZHOU Juan, JIN Dong, LU Shan, PU Ji, BAI Xiang-ning, YANG Jing, HU Shou-kui, XU Jian-guo
National Institute of Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention/State Key Laboratory for Infectious Disease Control and Prevention, Beijing 102206, China
Abstract：To isolate Enterococcus faecium from yaks in Qinghai-Tibet Plateau, China and detect its virulence genes and antibiotic resistance, the strains were isolated by Streptococcal medium and were identified by biochemical and 16s rDNA methods. The strains were then analyzed by pulsed-field gel-electrophoresis of digested chromosomal DNA fragments. The virulence genes were detected by PCR and confirmed by sequencing. Antibiotic resistance was performed by the K-B disk method with 16 antibiotics that were widely used in E. faecium. Results showed that 33 E. faecium strains were isolated from 320 fecal samples of yaks. A total of six virulence genes were detected by PCR method, including cytolysin (cylA), gelatinase (gelE), enterococcal surface protein (esp), collagen-binding-adhesin (acm), aggregation substance (asa1) and hyalronidase (hyl). The gene asa1 was found in 6.1% strains tested, followed by acm and hyl (3.0%). None of isolates was tested positive for the rest three virulence genes. Nineteen of 33 isolates were resistant to antibiotics, including 4 isolates having multidrug-resistance and 15 isolates being resistant to only one antibiotic. Of the 16 antibiotics tested, rifampicin resistance was found to be the most prevalent, accounting for 48.5% of isolates, followed by penicillin G (15.2%), tetracycline (12.1%), doxycycline (12.1%), erythromycin (9.1%), ampicillin (6.1%), high-level gentamicin (6.1%), ciprofloxacin (6.1%), fosfomycin (6.1%), and levofloxacin (6.1%). All of the isolates were 100% susceptible to vancomycin, teicoplanin and chloromycetin. Thirty-three E. faecium strains displayed 30 PFGE patterns and then were divided into 8 clusters from A to H, 6 of which included antibiotic-resistant strains. The yaks in the Qinghai-Tibetan Plateau are releasing E. faecium through feces. Those isolates carried some virulence genes and were resistant to various antibiotics, indicating potential hazard to human health.
周娟, 金东, 卢珊, 濮吉, 白向宁, 杨晶, 胡守奎, 徐建国. 青藏高原牦牛携带屎肠球菌及其毒力基因和耐药性检测[J]. 中国人兽共患病学报, 2015, 31(4): 298-302.
ZHOU Juan, JIN Dong, LU Shan, PU Ji, BAI Xiang-ning, YANG Jing, HU Shou-kui, XU Jian-guo. Virulence genes and antibiotic resistance of Enterococcus faecium isolated from yaks in Qinghai-Tibet Plateau, China. Chinese Journal of Zoonoses, 2015, 31(4): 298-302.
[1] Treitman AN, Yarnold PR, Warren J, et al. Emerging incidence of Enterococcus faecium among hospital isolates (1993 to 2002)[J]. J Clin Microbiol, 2005, 43(1): 462-463. doi:10.1128/JCM.43.1.462-463.2005 [2] Freitas AR, Tedim AP, Novais C, et al. Global spread of the hyl(Efm) colonization-virulence gene in megaplasmids of the Enterococcus faecium CC17 polyclonal subcluster[J]. Antimicrob Agents Chemother, 2010, 54(6): 2660-2665. [3] Hu FP, Zhu DM, Wang F, et al. CHINET 2013 surveillance of bacterial resistance in China[J]. Chin J Infect Chemother, 2014(05): 365-374. (in Chinese) 胡付品, 朱德妹, 汪复,等 .2013年中国CHINET细菌耐药性监测[J]. 中国感染与化疗杂志, 2014(05): p. 365-374. [4] Yang JC, Li MG. Antimicrobial susceptibility testing of twenty Enterococous faecium strains[J]. Lab Med Clin, 2006(7): 349. (in Chinese) 杨尖措,李满桂, 20例屎肠球菌的耐药性分析[J]. 检验医学与临床, 2006(7):349. [5] van den Bogaard AE, Jensen LB, Stobberingh EE. Vancomycin-resistant enterococci in turkeys and farmers[J]. N Engl J Med, 1997, 337(21): 1558-1559. doi:10.1056/NEJM199711203372117 [6] Lu HZ, Weng XH, Li H, et al. Enterococcus faecium -related outbreak with molecular evidence of transmission from pigs to humans[J]. Clin Microbiol, 2002, 40(3): 913-917. doi:10.1128/JCM.40.3.913-917.2002 [7] Rai AK, Tamang JP, Palni U. Microbiological studies of ethnic meat products of the Eastern Himalayas[J]. Meat Sci, 2010, 85(3): 560-567. doi:10.1016/j.meatsci.2010.03.006 [8] Vankerckhoven V, Autgaerden TV, Vael C, et al. Development of a multiplex PCR for the detection of asa 1, gelE , cylA , esp , and hyl genes in enterococci and survey for virulence determinants among European hospital isolates of Enterococcus faecium [J]. J Clin Microbiol, 2004, 42(10): 4473-4479. doi:10.1128/JCM.42.10.4473-4479.2004 [9] Sharifi Y, Hasani A, Ghotaslou R, et al. Survey of virulence determinants among vancomycin resistant Enterococcus faecalis and Enterococcus faecium isolated from clinical specimens of hospitalized patients of North west of Iran[J]. Open Microbiol J, 2012, 6: 34-39. doi:10.2174/1874285801206010034 [10] Graves LM, Swaminathan B. PulseNet standardized protocol for subtyping Listeria monocytogenes by macrorestriction and pulsed-field gel electrophoresis[J]. Int J Food Microbiol, 2001, 65(1-2): 55-62. [11] Wu LX, Huang WX. The molecular biological mechanism of vancomycin-resistant and virulence factors of Enterococcus faecium [J]. Inter J Epidemiol Infect Dis, 2006(2): 132-135. (in Chinese) 吴利先 ,黄文祥. 屎肠球菌耐万古霉素的分子生物学机制及毒力因子[J]. 国际流行病学传染病学杂志, 2006(2):132-135. [12] Nallapareddy SR, Qin X, Weinstock GM, et al. E nterococcus faecalis adhesin, ace, mediates attachment to extracellular matrix proteins collagen type IV and laminin as well as collagen type I[J]. Infect Immun, 2000, 68(9): 5218-5224. [13] Rice LB, Carias L, Rudin S, et al. A potential virulence gene, hylEfm, predominates in Enterococcus faecium of clinical origin[J]. J Infect Dis, 2003, 187(3): 508-512. [14] Zhong HJ. Antimicrobial susceptibility testing of Enterococous faecium [J]. Lab Med Clin, 2008(03): 187. (in Chinese) 仲海娟. 屎肠球菌的耐药性分析[J]. 检验医学与临床, 2008(3):187. [15] Long YX, Wang Z. Clinical distribution and analysis of drug resistance of Enterococcus from pediatric patients in XiNing[J]. Qinghai Med J, 2012(9): 71-72. (in Chinese) 龙岩秀,王珍. 西宁地区儿童肠球菌属的临床分布及耐药性分析[J]. 青海医药杂志, 2012(9): 71-72.
2015, Vol. 31 
