标题：儿童多重耐药肠球菌感染流行病学及耐药基因筛选

      作者：张书婉 1，黄君华 2
    (1.西安市儿童医院检验科，陕西 西安 710003；
2.西安医学院医学技术系，陕西 西安 710021)

      卷次： 2015年26卷17期

      【摘要】 目的 了解儿童感染肠球菌的临床分布、耐药表型和耐药基因的携带情况，为临床合理用药、控制
院内感染及流行病学调查提供依据。方法 收集西安市儿童医院 2014年 2月至 2015年 1月分离的肠球菌 180
株，用K-B法检测12种抗菌药物的耐药情况，运用多重PCR检测aac(6')-Ie-aph9(2'')-Ia、aph(2'')-Ib、aph(2'')-Ic、aph
(2'')-Id、erm(B)、mef(A)、tet(M)、tet(L)等耐药基因。结果 在 180株临床分离株中屎肠球菌 118株，粪肠球菌 46
株，其他肠球菌16株；其中分离自尿液的最多，占34.4%。药敏结果显示屎肠球菌对红霉素和四环素的耐药率分
别为84.7%和67.8%，高浓度庆大霉素耐药(HLGR)菌株占83.0%；粪肠球菌对红霉素和四环素的耐药率为82.6%
和 82.6%，HLGR菌株占 73.9%；未发现利奈唑胺和万古霉素耐药菌株。140株HLGR肠球菌中 aac(6')-Ie-aph
(2'')-Ia检出率为 92.8%，aph(2'')-Ib、aph(2'')-Ic、aph(2'')-Id均为阴性。150株红霉素耐药菌株中 erm(B)基因的检
出率为 66.6%，未检测到 mef(A)基因。126株四环素耐药菌株中，tet(M)和 tet(L)的检出率分别为 98.4%和
80.9%。结论 儿童肠球菌感染主要由屎肠球菌和粪肠球菌引起，且以尿路感染最为常见；多重耐药情况严重，
耐药性由多基因支配，HLGR为医院感染的重要耐药菌，主要通过aac(6')-Ie-aph(2'')-Ia基因介导；红霉素的耐药
性主要通过 erm(B)基因介导；四环素的耐药基因以 tet(M)和 tet(L)多见。

      【关键词】 儿童；肠球菌；流行病学；多重耐药；耐药基因

      【中图分类号】 R725.7 【文献标识码】 A 【文章编号】 1003—6350（2015）17—2554—04


Clinical epidemiology and antibiotic resistant genes of multidrug-resistant Enterococcus isolated from infected
children.
ZHANG Shu-wan 1, HUANG Jun-hua 2. 1. Department of Clinical Laboratory, Xi'an Children's Hospital, Xi’an
710003, Shaanxi, CHINA; 2. Department of Medical Technology, Xi'an Medical University, Xi'an 710021, Shaanxi,
CHINA

【Abstract】 Objective To investigate the clinical epidemiological trend and antibiotic resistant pattern of En-
terococci isolated from infected children in order to guide the rational use of antibiotics and effective surveillance of
nosocomial infections. Methods One hundred and eighty strains of Enterococci isolated from infected children in
Xi'an Children's Hospital from February 2014 to January 2015 were collected and analyzed for epidemiological distri-
bution and antibiotic susceptibility profile by K-B Method. Multiplex polymerase chain reaction (PCR) was used to de-
tect the resistance genes for gentamycin [aac(6')-Ie-aph9(2'')-Ia, aph(2'')-Ib, aph(2'')-Ic, aph(2'')-Id], erythromycin [erm
(B), mef(A)], tetracycline [tet(M), tet(L)]. Results Among the 180 isolates, which were mainly from urine (34.4%),
there were 118 strains of Enterococcus faecium, 46 strains of E. faecalis and 16 strains of Enterococci spp (8.9%). Antibi-
otic susceptibility of Enterococci against 12 antibiotics was determined by K-B method. High-level gentamycin resis-
tance (HLGR) was present in 83.0% of E. faecium and 73.9% of E. faecalis isolates. Resistance to erythromycin and
tetracycline was highly prevalent in E. faecium (84.7% and 67.8%, respectively) and E. faecalis (82.7% and 82.6%, re-
spectively). Among the 140 HLGR isolates, the most prevalent resistant determinant was aac(6')-Ie-aph(2'')-Ia
(92.9%), while none of the isolates harbored aph(2'')-Ib, aph(2'')-Ic or aph(2'')-Id. The erm(B) gene was responsible
for erythromycin resistance in 66.6% of the erythromycin resistant enterococcal isolates, while other erythromycin
resistant genes were not detected. The tet(M) and tet(L) genes were successfully amplified from 98.4% and 80.9% of
tetracycline resistant isolates, respectively. There was no linezolid and vancomycin resistance. Conclusion Entero-
cocci are important nosocomial pathogens with E. faecium and E. faecalis species most commonly isolated from clini-
cal specimens in children. Urinary tract infection is the most common infection of Enterococcus for children. HLGR
has become the important antibiotic resistance bacteria, which results in nosocomial infection, and the aac(6')-Ie-aph
(2")-Ia gene is the main aminoglycoside-modifying enzyme gene which causes HLGR. erm(B) is the most prevalent
genotype in the erythromycin resistant isolates, while harbouring tet(M) and tet(L) is the cause of tetracycline resis-
tance.

      【Key words】 Children; Enterococcus; Epidemiology; Multidrug resistance; Resistance genes