我国非伤寒沙门菌对多粘菌素的耐药现况及mcr-1基因携带概况

目的 初步探究我国非伤寒沙门菌对多粘菌素的耐药情况。方法 利用微量肉汤稀释法,测定不同来源404株非伤寒沙门菌对多粘菌素B及多粘菌素E的最小抑菌浓度（MIC）,计算耐药率,推测野生沙门菌株的耐药阈值。同时利用聚合酶链式反应（PCR）方法检测菌株携带mcr-1基因的情况。结果 404株沙门菌对多粘菌素B及E的MIC范围为0.125 g/ml至16 g/ml,对多粘菌素B的MIC50、MIC90分别为1 g/ml和8 g/ml;对多粘菌素E的MIC50、MIC90分别为2 g/ml和8 g/ml。优势血清型鼠伤寒沙门菌、肠炎沙门菌及德尔卑沙门菌对多粘菌素B及E的MIC值分布不同。以8 g/ml为耐药阈值判定折点,实验菌株对多粘菌素B及E的耐药率分别为10.89%和15.84%;其中食源性沙门菌、人源性沙门菌及动物源性沙门菌对多粘菌素B的耐药率分别为12.50%、17.16%和0.00%（P0.01）;对多粘菌素E的耐药率分别为8.30%、27.94%和0.78%（P0.01）。发现7株同时耐多粘菌素及三代头孢的菌株。发现1株人源鼠伤寒沙门菌携带可转移的mcr-1基因,且该菌株产ESBLs。结论 发现我国人源产ESBLs的沙门菌携带mcr-1基因。根据体外药敏结果,非伤寒沙门菌对多粘菌素B及E的耐药折点设为8 g/ml较宜。沙门菌对多粘菌素的耐药率尚处于低水平,应加强不同来源沙门菌对多粘菌素的耐药监测。     

Low level of polymyxin resistance among nonclonal mcr-1–positive Escherichia coli from human sources in Brazil

We report 26 human isolates of mcr-1–positive Escherichia coli, most of them (65.4%) with a polymyxin B MIC of 2?mg/L. Seventeen out of the 24 mcr-1–positive E. coli proved to be nonclonal by rep-PCR which strengthens the hypothesis of environmental or animal origin of these strains and reinforces the one health context of antimicrobial resistance.     

Use of a surfactant (polysorbate 80) to improve MIC susceptibility testing results for polymyxin B and colistin

Accurate determination of in vitro activity for polymyxin class agents has consistently been a problem due to their physical–chemical characteristics that can be influenced by the constituents of reference and/or standardized susceptibility testing methods. We evaluated the impact of using polysorbate 80 (P-80), a surfactant, in reference broth microdilution (BMD) methods when testing polymyxin B and colistin against 247 clinical strains of Enterobacteriaceae (124 strains), Acinetobacter spp. (60 strains), and Pseudomonas aeruginosa (63 strains). All testing was performed in frozen-form BMD panels with and without 0.002% P-80. MIC results for both polymyxins were generally 4- to 8-fold lower when P-80 was added to the testing broth compared to Mueller-Hinton broth without the surfactant. Decreases were greatest in organisms having MIC values at ≤2 μg/mL and among Acinetobacter spp. Polymyxins should be tested with P-80 to more accurately assess the potencies of these agents necessary to treat multidrug-resistant Gram-negative bacilli.     

The clover-leaf test and inactivation of beta-lactam antibiotics by gram-negative rods

The suitability of a very sensitive modification of the clover-leaf test as a test for inactivation of beta-lactam antibiotics by gram-negative rods was examined. 143 Enterobacteriaceae and 9 strains of Pseudomonas aeruginosa were examined by the clover-leaf test and an antibiotic susceptibility test towards 12 beta-lactam antibiotics. The beta-lactamase activity of the strains was also examined by a sensitive modification of the chromogenic cephalosporin test. The strains of P. aeruginosa could not be clover-leaf tested as they inhibited the indicator strains. All the Enterobacteriaceae which had beta-lactamase activity according to the chromogenic test inactivated at least 1 of the antibiotics in the clover-leaf test. None of the Enterobacteriaceae without beta-lactamase activity inactivated any of the antibiotics. On the whole the results of the clover-leaf test and the results of the susceptibility test correlated well. But many Enterobacteriaceae were susceptible to an antibiotic in the susceptibility test even though they inactivated it according to the clover-leaf test and some Enterobacteriaceae were resistant to an antibiotic but did not inactivate it. Among the Enterobacteriaceae which had beta-lactamase activity according to the chromogenic cephalosporin test and which were intermediately susceptible to an antibiotic in the susceptibility test, many did not inactivate this antibiotic according to the clover-leaf test. If an infection with Enterobacteriaceae has to be treated by a beta-lactam antibiotic to which the strain is only intermediately susceptible, it might be advantageous to use an antibiotic which is not inactivated by the strain according to the clover-leaf test, but this lacks clinical confirmation.     

耐碳青霉烯类肠杆菌科细菌KPC和NDM-1β内酰胺酶耐药基因的研究

目的检测江苏盛泽医院耐碳青霉烯类肠杆菌科细菌的KPC和NDM-1耐药基因,分析耐碳青霉烯类的耐药机制。方法采用改良Hodge试验、亚胺培南-EDTA纸片协同试验和AmpC酶三维试验检测29株耐碳青霉烯类抗生素肠杆菌科细菌产酶情况;用PCR方法检测KPC及NDM-1两种碳青霉烯酶耐药基因。结果29株分离菌中,26株菌改良Hodge试验阳性,7株亚胺培南EDTA纸片协同试验阳性,7株AmpC酶三维试验阳性,16株携带KPC型碳青霉烯酶耐药基因,未扩增出NDM-1碳青霉烯酶耐药基因。结论该院耐碳青霉烯类抗生素肠杆菌科细菌的耐药机制主要是携带KPC型碳青霉烯酶基因。     

产超广谱β-内酰胺酶细菌耐药性分析

目的研究临床肠杆菌科细菌产超广谱β-内酰胺酶（ESBLs）的发生率及耐药性,为临床抗感染治疗提供依据。方法采用美国临床实验室标准化研究所（CLSI）推荐的初筛试验和表型确证试验检测ESBLs阳性菌株。结果196株肠杆菌科细菌检出产ESBLs菌89株（45．4％）;大肠埃希菌、肺炎克雷伯茵和变形杆菌在ESBLs阳性菌株中的构成比依次为46．1％、50．6％和1．1％,产酶率则分别为43．6％、51．1％和16．7％。89株产ESBLs菌的来源构成比为痰48．3％、尿29．2％、分泌物12．3％、血液7．9％。结论ESBLs的产生是肠杆菌科细菌对p内酰胺类抗菌药物耐药的重要机制,临床实验室应加强检测,指导临床合理使用抗菌药物。     

Decontamination of cephalosporin-resistant Enterobacteriaceae during selective digestive tract decontamination in intensive care units

OBJECTIVES: Prevalences of cephalosporin-resistant Enterobacteriaceae are increasing globally, especially in intensive care units (ICUs). The effect of selective digestive tract decontamination (SDD) on the eradication of cephalosporin-resistant Enterobacteriaceae from the intestinal tract is unknown. We quantified eradication rates of cephalosporin-resistant and cephalosporin-susceptible Enterobacteriaceae during SDD in patients participating in a 13 centre cluster-randomized study and from a single-centre cohort. METHODS: All SDD patients colonized with Enterobacteriaceae in the intestinal tract at ICU admission were included. Cephalosporin resistance was defined as resistance to ceftazidime, cefotaxime or ceftriaxone and aminoglycoside resistance as resistance to tobramycin or gentamicin. Duration of rectal colonization was determined by screening twice weekly during ICU stay. Swabs were inoculated on selective medium supplemented with tobramycin or cefotaxime. RESULTS: Five hundred and seven (17%) of 2959 SDD patients with at least one rectal sample were colonized with Enterobacteriaceae at ICU admission: 77 (15%) with cephalosporin-resistant Enterobacteriaceae and 50 (10%) with aminoglycoside-resistant Enterobacteriaceae. Fifty-six (73%) patients colonized with cephalosporin-resistant Enterobacteriaceae were successfully decontaminated before ICU discharge, as were 343 (80%) patients colonized with cephalosporin-susceptible Enterobacteriaceae (P?=?0.17). For aminoglycoside resistance, 31 (62%) patients were decontaminated, as were 368 patients (81%) colonized with aminoglycoside-susceptible Enterobacteriaceae (P??0.05 for all comparisons). CONCLUSIONS: SDD can successfully eradicate cephalosporin-resistant Enterobacteriaceae from the intestinal tract.     

某地区分离自呼吸系统感染患者产ESBLs、AmpC酶肠杆菌科细菌耐药性检测

目的 分析肠杆菌科细菌临床分离株产超广谱β-内酰胺酶(ESBLs)和头孢菌素酶(AmpC酶)情况,及其与肠杆菌科细菌耐药性的关系.方法 收集该地区12家医院2009～2010年分离自呼吸系统感染患者呼吸道标本的肠杆菌科细菌1 612株,双纸片增效法检测ESBLs、三维试验检测AmpC酶、K-B纸片法检测菌株耐药性,采用χ2检验进行统计学分析.结果 1 612株细菌中,产ESBLs和AmpC酶菌株检出率分别为45.0%(726/1 612)和11.6%(187/1 612),产酶株对多种抗菌药物的耐药率高于非产酶株;未检出碳青霉烯类抗菌药物耐药菌株.结论 分离自该地区呼吸道感染患者呼吸道标本的产ESBLs和AmpC酶肠杆菌科细菌具有多药耐药性,应加强细菌耐药性监测,采取有效措施防止耐药性的水平传播.     

肠杆菌科细菌碳青霉烯酶的检测

目的调查本院肠杆菌科细菌产碳青霉烯酶的情况。方法收集2010年1～5月临床分离的肠杆菌科细菌,采用K-B纸片法进行药敏试验,以三代头孢菌素、亚胺培南、美罗培南为检测药物,筛选出可能产碳青霉烯酶的菌株120株,采用改良的Hodge试验进行确证。结果在120株耐一种或多种三代头孢菌素,提示可能产生碳青霉烯酶的肠杆菌科细菌中,通过表型确证试验确证为阳性的细菌有4株,肺炎克雷伯菌2株,大肠埃希菌1株,弗劳地枸橼酸杆菌1株。结论表型确证试验阳性的细菌中,如需准确辨别亚型,最好用分子生物学方法检测基因序列。     

改良Hodge试验检测肠杆菌科IMP型碳青霉烯酶的性能评价

目的探讨改良Hodge试验（modified Hodge test,MHT）在检测肠杆菌科细菌IMP型碳青霉烯酶中的应用价值。方法以VITEK2Compact全自动细菌鉴定及药敏系统进行细菌鉴定和药敏试验,筛选2010-2012年非重复临床分离的碳青霉烯类药物敏感性降低的肠杆菌科细菌,以MHT进行产碳青霉烯酶表型确证试验,PCR检测碳青霉烯酶blaKPC、blaIMP;6如VIM、blaoXA-48及blandm-1基因型,阳性结果进行测序并Blast比对确定基因型。以基因测序结果为金标准,分析统计MHT检测肠杆菌科碳青霉烯酶的各项性能指标。结果本实验共收集62株碳青霉烯类药物敏感性降低的肠杆菌科细菌,包括肺炎克雷伯菌42株,阴沟肠杆菌12株,大肠埃希菌5株,产酸克雷伯菌3株;MHT检测阳性51株,占总株数的82．26％,肺炎克雷伯菌、阴沟肠杆菌、大肠埃希菌、产酸克雷伯菌分别占各自菌种的比例为83．33％,75．0％,80．0％,100．0％;经PCR扩增并测序证实27株为产IMP-4型菌株,20株为产IMP-8型菌株,其他15株为碳青霉烯酶阴性菌株;MHT检测肠杆菌科细菌产IMP型碳青霉烯酶的灵敏度为97．87％％,特异性为66．67％,阳性预测值为90．2％,阴性预测值为90．91％,检验效能为90．32％。结论MHT检测肠杆菌科细菌产IMP型碳青霉烯酶具有良好的灵敏度,但特异性偏低,建议进一步使用分子生物学技术检测碳青霉烯酶肠杆菌科细菌基因型。     

应用EDTA协同法检测肠杆菌科细菌产金属β-内酰胺酶的研究

目的探讨应用EDTA协同法检测肠杆菌科细菌产金属β-内酰胺酶（MBL）的准确性,为临床快速筛查产MBL的肠杆菌科细菌提供简便的方法。方法对碳青霉烯类抗生素敏感性降低的27株肠杆菌科细菌在M-H琼脂平板上用双纸片协同法检测其MBL,以EDTA.Na2为酶抑制剂,美罗培南为底物。同时利用聚合酶链反应（PCR）检测MBL的基因NDM-1A、NDM-1B、IMP、VIM和SIM,PCR扩增阳性的产物测序结果与GenBank数据库进行比对分析。结果对碳青霉烯类抗生素敏感性降低的27株肠杆菌科细菌运用EDTA协同法检测MBL的阳性菌株为4株,与PCR检测MBL结果一致。且PCR产物测序结果经比对分析后证实均为IMP-4型MBL。结论 EDTA协同法检测肠杆菌科细菌产MBL方法简便、结果可靠,适用于临床对碳青霉烯类抗生素敏感性降低的肠杆菌科细菌产MBL的快速筛查。     

某院近5年住院患者肠杆菌科细菌分布及耐药监测分析

目的对该院2013-2017年住院患者分离的肠杆菌科细菌分布及药敏情况进行统计分析,为临床治疗及合理选择抗菌药物提供依据。方法采用纸片扩散法(K-B法)或自动化仪器(VITEK2-compact系统)对临床分离的5562株非重复肠杆菌科细菌进行药敏试验,并按美国临床实验室标准化协会(CLSI)相关标准判断药敏结果。结果共收集该院临床分离的非重复肠杆菌科细菌5562株,其中大肠埃希菌2820株,肺炎克雷伯菌1607株,阴沟肠杆菌317株及其他肠杆菌科细菌818株。5年间肠杆菌科细菌的检出率基本持平,2013年为50.9%,2017年为51.1%。药敏试验数据显示,所有肠杆菌科细菌对哌拉西林/他唑巴坦、亚胺培南、厄他培南、头孢替坦和阿米卡星保持了高的敏感率(>90.0%),对头孢哌酮/舒巴坦、头孢他啶和头孢吡肟也有较高的敏感率(73.0%~89.3%),对氨曲南、庆大霉素、妥布霉素、左氧氟沙星、环丙沙星、氨苄西林/舒巴坦、头孢唑林、头孢曲松、复方磺胺甲噁唑的敏感率较低(27.3%~66.1%),对氨苄西林的敏感率最低(8.0%)。5年间,产超广谱β-内酰胺酶(ESBLs)大肠埃希菌检出率从62.7%上升到64.6%;产ESBLs肺炎克雷伯菌检出率从37.5%下降至30.5%。碳青霉烯类耐药肠杆菌科细菌(CRE)检出率为1.6%。结论肠杆菌科细菌对常见抗菌药物的耐药率总体呈下降趋势,但CRE菌株的日趋增多,给临床治疗造成严重影响,应充分利用细菌耐药监测结果进行感染控制,提高临床抗菌药物合理使用的意识,有效遏制该类菌株感染的发生。     

改良Hodge试验检测肠杆菌科细菌碳青霉烯酶的性能评估

目的 评估改良Hodge试验在碳青霉烯类药物敏感性降低的肠杆菌科细菌中检测碳青霉烯酶的效能.方法 收集2004-2008年我国16家教学医院的49株碳青霉烯类药物敏感性降低(亚胺培南、美罗培由或厄他培南的MIC≥2μg/ml)的肠杆菌科细菌;采用对倍琼脂稀释法测定其对亚胺培南、美罗培南和厄他培南的MIC;通过改良Hodge试验检测碳青霉烯酶;利用加苯硼酸或苯唑西林的改良Hodge试验区分碳青霉烯酶或AmpCs/ESBLs导致的阳性结果 ;采用PCR检测包括NDM-1型碳青霉烯酶基因在内的多种β内酰胺酶基因,并对PCR阳性产物测序鉴定.结果 49株菌中,36株菌对亚胺培南不敏感(MIC>4μg/ml),31株菌对美罗培由不敏感(MIC>4μg/ml),47株菌对厄他培南不敏感(MIC>2μg/ml).49株临床分离菌中23株菌改良Hodge试验刚性,包括9株弱阳性和14株强阳性.经过对菌株进行β内酰胺酶基因PCR和测序,发现9株Hodge弱阳性菌株中2株携带blaKPC-2,7株不携带碳青霉烯酶基因,但携带blaampC/blaESBL;14株强阳性菌株中4株携带blaKPC-2,8株携带blaIMP-4,2株携带blaIMP-8;26株改良Hodge试验阴性菌株均未携带碳青霉烯酶基因.所有49株菌均未检测到blaNDM-1.以碳青霉烯酶基因检测为标准,则改良Hodge试验对检测碳青霉烯类药物敏感性降低的肠杆菌科菌中碳青霉烯酶的敏感度为100%,特异度为79%,阳性预测值为70%,阴性预测值为100%,准确性为86%.结论 改良Hodge试验具有很好的敏感性,但存在一些假阳性结果 .利用苯硼酸和苯唑西林可有效区分改良Hodge试验的假阳性和真阳性.     

碳青霉烯类非敏感肠杆菌科细菌分子流行病学研究

摘要：目的：调查碳青霉烯类抗生素非敏感肠杆菌科细菌的流行情况,并研究其耐药性传播方式。 方法：收集本院临床分离的碳青霉烯类抗生素非敏感肠杆菌科细菌34株,用Vitek2 Compact系统进行细菌鉴定和常规药敏检测,改良Hodge试验筛选产碳青霉烯酶菌株,用肠杆菌基因间重复一致序列(enterobacterial repetitive intergenic consensus,ERIC)-PCR进行分子流行病学调查。PCR扩增Int 1、Int 2、Int 3整合酶基因,质粒接合和消除试验研究细菌耐药基因的传播方式。 结果：19株细菌改良Hodge试验阳性。来自7个不同科室的12株大肠埃希菌和17株阴沟肠杆菌可以分为3种和6种基因型,来自4个不同科室的5株肺炎克雷伯菌只有1种基因型。27株菌Int1基因阳性,未检出Int2和Int3基因。除骨科1株阴沟肠杆菌外,其余33株细菌质粒消除和接合试验均成功。 结论：本院碳青霉烯类抗生素非敏感肠杆菌科细菌主要发生在外科各科室;所有肺炎克雷伯菌和泌尿外科大肠埃希菌属同一基因型,表明此类菌株呈局部流行;碳青霉烯类抗生素非敏感肠杆菌科细菌耐药性主要通过质粒传播。     

In vitro activity of netilmicin (SCH 20569) against bacterial isolates from ill children.

A new aminoglycoside antibiotic, netilmicin, was tested against 306 clinical isolates from ill children and compared with sisomicin and gentamicin. Activity against Enterobacteriaceae was similar to that of gentamicin but less than that of sisomicin. Two gentamicin-resistant strains of Enterobacteriaceae (Klebsiella, MIC 6.25 microgram/ml, Escherichia coli, MIC 12.5 microgram/ml) were susceptible to netilimicin (MIC 3.12 microgram/ml). Netilmicin was ineffective against almost all strains of Pseudomonas but active against the majority of strains of Staphylococcus, Neisseria meningitidis and Haemophilus influenzae tested. Disc diffusion sensitivity results correlated in general with the agar dilution test. Netilmicin had little activity against Pseudomonas but may be useful in the treatment of infections due to gentamicin-resistant Enterobacteriaceae.     

糖尿病患者感染产ESBLs肠杆菌科细菌的耐药性及危险因素分析

目的 了解中山市糖尿病患者感染产超广谱β-内酰胺酶(extended spectrum β-Lactamases,ESBLs)肠杆菌科细菌的耐药性及危险因素。方法 收集2014年1月～2016年6月中山大学附属中山医院120例确诊糖尿病并发感染产ESBLs肠杆菌科细菌患者的临床标本132例和临床资料。通过VTIEK 2 COMPCT全自动微生物鉴定系统进行菌种鉴定和药物敏感试验; 使用VITEK 2 COMPCT高级专家系统判定菌株的耐药表型和耐药模式,同时根据是否产ESBLs,把主要致病菌大肠埃希菌分为ESBLs-positive组和ESBLs-negative组,比较两组在耐药模式之间的区别。对患者的各项临床资料进行logistic回归分析糖尿病并发感染产ESBLs肠杆菌科细菌的危险因素。结果糖尿病患者感染产ESBLs肠杆菌科细菌主要是大肠埃希菌,其次是肺炎克雷伯菌,感染标本来源主要是中段尿。大肠埃希菌和肺炎克雷伯菌对厄他培南和亚胺培南敏感度为100%,对头孢替坦和哌拉西林/他唑巴坦的敏感度大于98%。大肠埃希菌ESBLs-positive组和ESBLs-negative组在获得性青霉素酶、β-内酰胺类抗生素野生型、其他超广谱β-内酰胺酶和CTX-M型ESBLs四种耐药模式之间差异均有统计学意义(χ²=17.34,19.23,33.90,42.75,均P<0.05)。经logistic回归分析,年龄、住院次数、性别、糖尿病病程、收缩压、糖化血红蛋白水平、抗生素使用情况、感染前的治疗情况、类固醇药物应用、外科手术、侵入性操作、并发症等均不是产ESBLs肠杆菌科细菌感染的危险因素。结论 大肠埃希菌和肺炎克雷伯菌是糖尿病患者感染产ESBLs肠杆菌科的主要致病菌,感染部分主要是泌尿系统。产ESBLs肠杆菌对厄他培南、亚胺培南、头孢替坦和哌拉西林/他唑巴坦敏感。大肠埃希菌ESBLs-positive组和ESBLs-negative组主要表现为四种耐药模式的差异。年龄、住院次数和性别等常见因素均不是糖尿病患者感染产ESBLs肠杆菌科细菌的危险因素。     

890株临床分离肠杆菌科细菌分布和耐药性分析

目的 了解中山大学附属东华医院临床分离的890株肠杆菌科细菌的分布及对各类抗菌药物的耐药状况,为临床合理使用抗菌药物提供依据.方法 收集2010年从患者各种临床标本中分离的肠杆菌科细菌,采用K-B法进行药敏试验,用WHONET5.5软件对数据进行分析.结果 890株肠杆菌科细菌中大肠埃希菌456株(51.2%),克雷伯菌属227株(25.5%),肠杆菌属83株(9.3%).肠杆菌科细菌敏感率在80%以上的药物有亚胺培南、美罗培南、阿米卡星和哌拉西林/他唑巴坦等.大肠埃希菌对亚胺培南和美罗培南保持100.0%敏感率.肺炎克雷伯菌、阴沟肠杆菌和奇异变形杆菌对亚胺培南及美罗培南的敏感率均大于90.0%.结论 肠杆菌科细菌对多数常用抗菌药物耐药率呈上升趋势,对碳青霉烯类抗生素仍最敏感.定期进行耐药性监测有助于了解该院细菌耐药性变迁,为临床经验用药提供依据.     

Identification of Enterobacteriaceae: report of the British Society for Multipoint Technology collaborative study

Under the auspices of the British Society for Multipoint Technology, 84 strains of Enterobacteriaceae were identified by multipoint inoculation techniques in eight laboratories. Results were compared to assess the inter-laboratory reproducibility and reliability of each test. Identity of the test strains was also determined by use of two commercially produced kits. Most test strains were identified by the multipoint inoculation systems, which were cost effective and generally accurate, although some laboratories performed better than others. Reproducibility of some test results was variable.     

CIM，mCIM 和MHT 筛选肠杆菌科细菌产碳青霉烯酶的方法评价

目的 评估碳青霉烯类抑制法(carbapenem inactivation method,CIM)、改良碳青霉烯类失活法(modified carbapenem inactivation method,mCIM)和改良Hodge试验(modified hodge test, MHT )对肠杆菌科细菌碳青霉烯酶表型筛选能力。方法 以PCR检测碳青霉烯酶基因作为金标准,对120株耐碳青霉烯类肠杆菌科细菌(carbapenem-resistant enterbacteriaceae,CRE)和50株碳青酶烯类敏感的肠杆菌科细菌,分别进行CIM,mCIM和MHT表型筛选试验,评估三种方法的表型筛选能力。结果 120株CRE中,93株携带碳青霉烯酶耐药基因,表型筛选试验显示,CIM,mCIM和MHT的敏感度分别是95.6%,96.8%和95.8%,特异度分别为72.7%,92.3%和50%。三种方法筛选碳青霉烯酶,差异有统计学意义(χ²=12.796,P<0.05)。与PCR结果相比较,CIM,MHT和mCIM的一致率分别为90%,95%和77.4%,Kappa值分别为0.898,0.949和0.771。mCIM和CIM试验与PCR高度一致。50株碳青酶烯类敏感的肠杆菌科细菌PCR检测和三种方法均为阴性。结论 三种表型筛选方法均有较高的敏感度,但mCIM较CIM,MHT具有更高的特异度和一致率,是筛选CRE的有效方法。     

Use of surrogate antimicrobial agents to predict susceptibility to ertapenem

Broth or agar dilution susceptibility test results for Enterobacteriaceae (11,775 strains), anaerobes (2888 strains), staphylococci (2206 strains), Haemophilus spp. (840 strains), group A streptococci (280 strains), group B streptococci (269 strains), Streptococcus pneumoniae (709 strains), and 160 other streptococci were analyzed to identify surrogate antimicrobial agents to predict susceptibility to ertapenem. Ertapenem MIC interpretive categories approved by the United States FDA were compared to those of imipenem, oxacillin (staphylococci), or penicillin (streptococci). Ertapenem resistance was rare (1.2%) among 8187 consecutively collected clinical isolates of Enterobacteriaceae, including a large proportion of isolates from intensive care units. Absolute categorical agreement between ertapenem and imipenem, and very major (false susceptible) and major errors (false resistant) using imipenem to predict ertapenem results were 97.2%, 0.9%, and 0.4%, respectively, for Enterobacteriaceae (10,992 strains tested against both drugs) and 99.0%, 0.2%, and 0% for anaerobes. All Haemophilus spp., groups A and B streptococci, penicillin-susceptible and -intermediate S. pneumoniae, and other penicillin-susceptible streptococci were susceptible to ertapenem. All oxacillin-susceptible Staphylococcus aureus were ertapenem susceptible, except 1 that was intermediate. Surrogate antimicrobial agents that can be used to reliably predict ertapenem susceptibility by MIC tests are imipenem for Enterobacteriaceae and anaerobes, oxacillin for staphylococci, and penicillin for streptococci.