2012年中国CHINET血培养临床分离菌的分布及耐药性

The distribution and antibiotic resistance of clinical isolates from blood culture in 2012 CHINET surveillance program in China

目的了解2012年中国CHINET血培养分离菌的构成及耐药性。方法对中国CHINET 细菌耐药监测网2012年1月至12月所有血培养分离菌，按统一方案用K‐B纸片扩散法进行抗菌药物敏感试验。结果2012年自血标本中共获分离菌8490株，其中革兰阳性球菌占56．0％，革兰阴性杆菌占44．0％。居前10位的分离菌依次为凝固酶阴性葡萄球菌（CNS ）（35．5％）、大肠埃希菌（16．4％）、克雷伯菌属（9．8％）（其中91．1％为肺炎克雷伯菌）、肠球菌属（7．2％）、金黄色葡萄球菌（金葡菌）（7．2％）、不动杆菌属（5．9％）（其中93．8％为鲍曼不动杆菌）、草绿色链球菌（4．3％）、铜绿假单胞菌（3．2％）、肠杆菌属（2．4％）和洋葱伯克霍尔德菌（1．5％） ，占所有分离菌株的93．5％。甲氧西林耐药金葡菌（M RSA ）、甲氧西林耐药 CNS （MRCNS）分别占金葡菌和CNS的50．8％和61．7％。粪肠球菌对高浓度庆大霉素和氨苄西林的耐药率分别为29．0％和10． 9％，屎肠球菌对多数测试药物的耐药率显著高于粪肠球菌。草绿色链球菌对青霉素的耐药率为3．8％。儿童分离株中青霉素耐药肺炎链球菌株为31．2％，与成人分离株大致相仿（34．1％）。葡萄球菌属、肺炎链球菌、其他链球菌属和粪肠球菌中均未发现万古霉素和利奈唑胺耐药菌株，屎肠球菌对万古霉素的耐药率为3．5％。大肠埃希菌、肠杆菌属、沙雷菌属、变形菌属和枸橼酸菌属等肠杆菌科细菌对碳青霉烯类的耐药率均在10．0％以下，唯克雷伯菌属对碳青霉烯类耐药率为11．2％-19．8％。不发酵糖革兰阴性杆菌对碳青霉烯类耐药率较高，铜绿假单胞菌对碳青霉烯类的耐药率近30．0％，对不动杆菌属耐药率达70．0％以上。结论2012年中国CHINET监测资料显示，血培养分离菌仍以革兰阳性菌为主，但检出比例有所下降，革兰阴性菌有所上升。血培养分离株对常用抗菌药物耐药性仍严重，尤其革兰阴性菌对碳青霉烯类耐药率呈上升趋势。因此应合理应用抗菌药物，并加强医院感染控制措施抑制耐药菌传播。

Objective To investigate the distribution and antibiotic resistance of clinical isolates from blood culture in 15 hospitals across China in 2012 .Methods The susceptibilities of blood culture isolates to more than 20 antimicrobial agents were determined by Kirby‐Bauer method according to a unified protocol .Results A total of 8 490 strains were isolated from blood samples in 2012 ,of which gram positive cocci and gram negative bacilli accounted for 56 .0% and 44 .0% respectively .The top ten isolates were coagulase negative Staphylococcus （CNS ） （35 .5% ） , E . coli （16 .4% ） , K lebsiella spp . （9 .8% ） , Enterococcus spp .（7 .2% ） ,S .aureus （7 .2% ） ,Acinetobacter spp .（5 .9% ） ,S .viridans （4 .3% ） ,P .aeruginosa （3 .2% ） , Entrobacter spp .（2 .4% ） and Burkholderia spp .（1 .5% ） ,together accounting for 93 .5% of all the blood culture isolates . The prevalence of MRSA among S .aureus and MRCNS among CNS was 50 .8% and 61 .7% ,respectively .About 29 .0% and 10 .9% of the E . f aecalis isolates were resistant to high level gentamicin and ampicillin respectively ,significantly lower than thatofE.faecium.Penicillinresistancewasfoundin3.8% oftheS.viridansstrainsand31.2% oftheS.pneumoniae strains isolated from adults , and 34 .1% of the S . pneumoniae strains isolated from children . Vancomycin‐resistant Enterococcus was identified in 3 .5% of the E . f aecium isolates .No strains were found resistant to vancomycin or linezolid in Staphylococcus spp .,Streptococcus spp .,S .pneumoniae and E .faecalis .About 11 .2% to 19 .8% of the Klebsiella strains were resistant to carbapenems .For the other Enterobacteriaceae species ,less than 10 .0% of the isolates were resistant to carbapenems .Nonfermenters were highly resistant to carbapenems ,especially Acinetobacter spp .（71 .6% resistant） and P .aeruginosa （nearly 30 .0% resistant） .Conclusions Gram positive cocci still play an important role in blood stream infections in 2012 CHINET program ,but the proportion decreases compared to previous years .Resistance to the fist line antibiotics is common among the blood isolates ,especially the increase of carbapenem resistance in gram negative bacteria .Antimicrobial agents should be used appropriately to reduce the selection pressure . Hospital infection control measures should be strengthened to prevent the spread of resistant organisms .