肺炎链球菌对大环内酯类耐药性分析

目的 探索郯城县区肺炎链球菌分离株对大环内酯类耐药性及其治疗情况.方法 收集郯城县社区和临床分离的肺炎链球菌 ,根据CLSI标准,用K-B法、Etest法检测肺炎链球菌对红霉素和克林霉素的耐药性及对红霉素的耐药表型.结果 493株肺炎链球菌中红霉素不敏感菌株489株 ,对克林霉素不敏感菌株482株,其中 ermB基因介导的红霉素耐药菌株482株 ,占98.6% , mefE基因介导的红霉素耐药菌株7株,占1.4%.结论 郯城县区对红霉素和克林霉素近乎全部耐药 ,ermB基因介导的靶位改变是郯城县区肺炎链球菌对大环内酯类抗菌药物的主要耐药机制.     

红霉素耐药肠球菌的质粒接合试验

目的：研究儿童临床分离的30株肠球菌,红霉素耐药性在同属同种、同属异种和异属细菌之间的传递。方法：使用临床实验室标准化研究所（CLSI）推荐的琼脂稀释法筛选30株耐红霉素的肠球菌,通过滤膜接合法进行质粒接合转移试验,采用PCR检测供体菌、受体菌和接合子ermB基因和转座子Tn1545、Tn917。结果：13株粪肠球供体菌通过质粒接合转移试验后得到13株接合子,红霉素最小抑菌浓度（MIC）≥512μg／ml,除原供体菌1株粪肠球菌阴性外,其余的12株接合子全部携带ermB基因,且ermB基因均同时存在于转座子Tn1545和Tn917;16株屎肠球供体菌和1株海氏肠球供体菌通过质粒接合转移试验后得到17株接合子,红霉素MIC≥512μg／ml,除原供体菌1株屎肠球菌阴性外,其余16株接合子全部携带ermB基因,并且有11株接合子ermB基因同时存在于Tn1545和Tn917,4株接合子ermB基因仅存在于Tn1545,1株接合子ermB基因仅存在于Tn917;30株肠球菌通过质粒接合转移试验后得到的30株金黄色葡萄球菌接合子,红霉素MIC≥512μg／ml,除原供体菌1株粪肠球菌和1株屎肠球菌阴性外,其余的28株接合子全部携带ermB基因,其中ermB基因同时存在于Tn1545和Tn917的为23株,4株接合子ermB基因仅存在于Tn1545,1株接合子ermB基因仅存在于Tn917。结论：肠球菌对红霉素的耐药性可以在同属同种、同属异种和异属之间进行传递;红霉素的耐药性与ermB基因存在一致,ermB基因与Tn1545和Tn917密切相关,ermB基因与Tn1545和Tn917可以在同属同种、同属异种和异属之间进行传递。     

肺炎链球菌对红霉素耐药机制的研究

目的了解武汉地区肺炎链球菌的红霉素耐药机制。方法收集152株肺炎链球菌，琼脂稀释法测定抗菌药物最低抑菌浓度，红霉素-克林霉素双纸片扩散法检测耐药表型，聚合酶链式反应检测红霉素耐药基因ermB和mefA。结果152株肺炎链球菌红霉素耐药率达84．21％（128／152），耐药表型主要为cML SB（98．44％），2抹菌（1．56％）为M表型耐药。128株红霉素耐药肺炎链球菌ermB基因总检出率98．44％（126／128），其中40株菌（31．25％）同时检出ermB和mefA基因，2株菌（1．56％）仅检出mefA基因。结论武汉地区红霉素耐药肺炎链球菌的发生率高，ermB基因是最主要的耐药机制，介导cMLSa表型耐药，双纸片扩散法对此耐药表型的检测有很好的预见性。     

孕晚期妇女B族链球菌携带情况及耐药机制研究

目的研究孕晚期妇女B族链球菌（GBS）携带情况及大环内酯类等抗菌药物的耐药表型和耐药机制。方法收集848份孕晚期妇女阴道/肛门拭子样本,采用哥伦比亚血琼脂培养基和GBS显色培养基进行培养。采用纸片扩散法进行GBS红霉素、克林霉素、左氧氟沙星及万古霉素药敏试验。聚合酶链反应（PCR）检测大环内酯类抗菌药物耐药基因ermA、ermB、ermC、ermTR、mefA/E及林可酰胺抗菌药物耐药基因lnuB。结果848份标本共筛查出95株GBS,阳性率11.2%。红霉素、克林霉素和左氧氟沙星耐药率分别为78.9%、82.1%、30.5%,万古霉素全敏感。95株GBS经D环试验检测,69株为结构耐药表型cMLSB,5株为诱导耐药表型iMLSB,1株为红霉素耐药克林霉素敏感M表型,3株为红霉素敏感克林霉素耐药L表型。PCR检测到59株GBS携带ermB基因,29株携带mefA/E基因,19株携带lnuB基因,2株携带ermTR基因,未检测到ermA和ermC基因。48株GBS仅含一种耐药基因,27株GBS含两种及以上耐药基因。结论温州地区孕晚期妇女GBS携带率高,需要对所有孕晚期妇女进行GBS筛查试验;GBS红霉素和克林霉素耐药率高,并且以cMLSB耐药表型为主。大环内酯类耐药基因以ermB为主;lnuB基因携带率高于其他地区。     

肺炎链球菌临床分离株耐药性及红霉素耐药相关基因的研究

目的了解本院临床肺炎链球菌感染状况、耐药性以及耐药基因流行情况。方法2004年1月~2005年12月从患者不同标本分离鉴定肺炎链球菌,采用NCCLS标准K-B法对临床常用抗生素进行耐药分析、PCR检测红霉素耐药基因ermB和mefA。结果分离129株肺炎链球菌,其中青霉素敏感率为42.4%,红霉素耐药率为80.6%。104株红霉素耐药肺炎链球菌中,ermB基因检出率为97.1%,mefA基因检出率为41.3%,41株同时含有ermB和mefA基因。结论本院临床分离肺炎链球菌耐药性高,红霉素耐药基因主要为ermB。     

β-溶血性链球菌对红霉素、克林霉素耐药性及对大环内酯类抗生素耐药机制研究

目的 探讨BHS的耐药性及耐药基因携带情况。方法 采用药敏纸片法测定BHS对红霉素、克林霉素的药物敏感性,应用PCR法检测其对大环内酯类药物耐药基因ermB、mefA。结果 BHS群对红霉素及林可酰胺类药物克林霉素的耐药率较高。ermB基因阳性率为84.4%,其中GCS、GFS对该基因携带率最高均为100%,7株红霉素敏感菌株中检测出ermB基因,与耐药表型不符。mefA基因阳性率为3.1%,均在红霉素耐药菌株中检出。有1株同时携带ermB、mefA基因。结论 BHS群对大环内酯类药物及林可酰胺类药物耐药率较高,其对红霉素耐药主要与核糖体糖蛋白甲基化有关。     

大环内酯类药物对肺炎链球菌的防耐药突变浓度的研究

目的 测定大环内酯类药物对肺炎链球菌的防耐药突变浓度(mutant prevention concentration,MPC),扩增突变选择窗(mutant selection window,MSW)内筛选的耐药突变体的耐药基因,以了解肺炎链球菌对大环内酯类药物耐药的发生机制.方法 肉汤法富集1010CFU/ml ATCCA9619,采用平板二倍稀释法测定罗红霉素和阿奇霉素对ATCC49619的最低抑菌浓度(minimal inhibitory concentration,MIC)、MIC99、初测MPC(Provisional MPC,MPCpr)以及MPC.PCR法扩增不同药物筛选出的耐药突变株的耐药基因ermB和mefA并测序.结果 罗红霉素和阿奇霉素对ATCC49619的MPC分别为0.80μg/ml和0.51 μg/ml,细菌耐药选择指数(MPC/MIC99)为5.0和3.9.筛选出的耐药突变株中扩增出ermB耐药基因.结论 通过凋整药物剂量,可以限制对大环内酯类耐药的肺炎链球菌突变体的富集.肺炎链球菌对大环内酯类药物耐药机制可能与携带ermB基因有关.     

53株临床分离肠球菌的耐药性及相关耐药基因分析

目的 了解临床分离的53株肠球菌的耐药性与耐药基因的存在状况.方法 采用VITEK-2全自动细菌鉴定仪检测肠球菌对9种抗生素的药敏结果,对该细菌进行总DNA的提取,用聚合酶链反应(PCR)检测耐药基因,结合药物敏感试验分析菌株的耐药特征.结果 53株肠球菌检出含红霉素耐药基因ermB 26株,占49.0％；含毒力因子mefA9株,占17.0％;含Tn1546/Tn916转座子19株,占35.8％；含Tn917转座子11株,占20.8％.53株肠球菌对红霉素耐药高达94.3％,对高水平庆大霉素、高水平链霉素、环丙沙星、四环素和氨苄西林的耐药分别为75.5％、73.6％、75.5％、66.0％、62.3％;对万古霉素和利奈唑胺敏感均高达98.1％.结论 耐药基因与肠球菌耐药性密切相关,随着医学环境的改变,肠球菌对抗生素耐药性正逐步上升.     

肺炎链球菌分离株红霉素耐药erm、mef基因检测研究

目的：了解引起苏州地区儿科临床肺炎链球菌(Sp)分离株红霉素耐药的状况。方法：设计、优化与红霉素耐药相关的红霉素核糖体甲基化酶基因(erm)和主动外排转运体基因(mef)PCR检测体系，对2002年9月～2003年4月呼吸道感染患儿痰标本中分离到的23株Sp菌(红霉素敏感表型3例、中敏3例、耐药17例)进行检测。结果：红霉素耐药、中敏、敏感Sp菌分别检出耐药基因94．1％(16／17)、100％、33．3％(1／3)。erm B基因：PCR检出率43．5％(10／23)；erm A/erm B基因通用兼并引物PCR检出率69．6％(16／23)；erm A基因PCR检出率261％(6／23)；erm或／和mef基因检出率87．0％(20／23)。携带erm基因的耐药表型率93．3％(14／15)，其中单独ermA基因为100％(4／4)；ermB ermA/B基因为87．5％(14／16)。单独携带mef基因的耐药表型率50％(2／4)，而erm或／和mef基因为80％(16／20)。结论：本地区Sp菌株中存在erm A、erm B和mef基因；三者单独或共同表达均可致Sp菌红霉素耐药；前二者致Sp菌红霉素耐药率高于后者。     

武汉地区肺炎链球菌的红霉素耐药性分析及血清分型研究

目的 研究武汉地区肺炎链球菌的红霉素耐药率、耐药表型及肺炎链球菌血清分型分布情况.方法 以琼脂稀释法测定红霉素、青霉素及其他大环内酯类等抗菌药物对304株肺炎链球菌的最低抑菌浓度(MIC),采用荚膜肿胀试验进行血清分型,以双纸片法测定红霉素耐药菌株的耐药表型.结果 304株肺炎链球菌红霉素耐药率高达84.21%(256/304).红霉素耐药菌株中,cMLSB型耐药占98.44%(252/256),M型耐药仅占1.56%(4/256).血清分型涉及20个血清型、群,主要集中在19、23、6、15和14血清群,其中PNSSP集中分布在6、19、23和未分型血清群.结论 武汉地区红霉素不敏感肺炎链球菌的发生率较高,其耐药表型以cMLSB型为主,双纸片法对此耐药表型的检测有很好的预见性.血清分型,尤其多重耐药菌株以6、19和23血清群为主,推荐采用疫苗免疫预防肺炎链球菌感染.     

Characterization of erythromycin-resistant Streptococcus pneumoniae isolates causing invasive diseases in Chinese children

Background  Erythromycin-resistant Streptococcus pneumoniae isolates that causing invasive pneumococcal diseases (IPD) in Chinese children remain uncharacterized. This study aims to identify the resistance genes associated with erythromycin resistance and to determine the genetic relationships of IPD isolates in Chinese children.

Methods  A total of 171 S. pneumoniae strains were isolated from 11 medical centers in China from 2006 to 2008. All the isolates were characterized via serotyping and antibiotic susceptibility determination. The erythromycin-resistant isolates were further characterized via ermB and mefA gene detection, multi-locus sequence typing analysis, and pulsed-field gel electrophoresis.

Results  A total of 164 (95.9%) isolates showed resistance to erythromycin, of which 162 strains with high high-level resistance (MIC ≥ 256 μg/ml). A total of 104 (63.4%) isolates carry the ermB gene alone, whereas 59 (36.0%) harbor both ermB and mefA genes. Of the 59 strains, 54 were of serotypes 19A and 19F and were identified as highly clonal and related to the Taiwan^19F-14 clone.

Conclusions The erythromycin resistance rate in IPD isolates is significantly high and is predominantly mediated by the ermB gene. Isolates that carry both ermB and mefA genes are predominantly of serotypes 19A and 19F.

     

Macrolide resistance among invasive Streptococcus pneumoniae isolates

CONTEXT: Macrolide antibiotics, including erythromycin, clarithromycin, and azithromycin, are the mainstays of empirical pneumonia therapy. Macrolide resistance among Streptococcus pneumoniae, the most common cause of community-acquired pneumonia, is increasing in the United States. Whether resistance is a significant problem or whether macrolides remain useful for treatment of most resistant strains is unknown. OBJECTIVE: To examine the epidemiology of macrolide-resistant pneumococci in the United States. DESIGN AND SETTING: Analysis of 15 481 invasive isolates from 1995 to 1999 collected by the Centers for Disease Control and Prevention's Active Bacterial Core surveillance system in 8 states. MAIN OUTCOME MEASURES: Trends in macrolide use (1993-1999) and resistance and factors associated with resistance, including examination of 2 subtypes, the M phenotype, associated with moderate minimum inhibitory concentrations (MICs), and the MLS(B) phenotype, associated with high MICs and clindamycin resistance. RESULTS: From 1993 to 1999, macrolide use increased 13%; macrolide use increased 320% among children younger than 5 years. Macrolide resistance increased from 10.6% in 1995 to 20.4% in 1999. M phenotype isolates increased from 7.4% to 16.5% (P<.001), while the proportion with the MLS(B) phenotype was stable (3%-4%). The median erythromycin MIC (MIC(50)) of M phenotype isolates increased from 4 microg/mL to 8 microg/mL. In 1999, M phenotype strains were more often from children than persons 5 years or older (25.2% vs 12.6%; P<.001) and from whites than blacks (19.3% vs 11.2%; P<.001). CONCLUSIONS: In the setting of increasing macrolide use, pneumococcal resistance has become common. Most resistant strains have MICs in the range in which treatment failures have been reported. Further study and surveillance are critical to understanding the clinical implications of our findings.     

常见球菌红霉素耐药基因研究

目的 探讨常见球菌红霉素耐药基因存在状况。方法 对常见细菌国内分离株进行红霉素耐药相关的红霉素核糖体甲基化酶基因（ermA／B／C／G／Q、errnTiB、crmF）、主动外排转运基因（mefA）检测。结果 肺炎链球菌、MRSA、MRCNS、粪肠球菌、屎肠球菌的crm基因检出率较高,其中肺炎链球菌并可检出mefA基因。结论 常见球菌国内分高株红霉素耐药的常见机制为携带红霉素梭糖体甲基化酶基因。     

2009～2011年武汉大学人民医院感染肺炎链球菌的耐药性分析

目的监测武汉大学人民医院肺炎链球菌的耐药趋势,为临床合理应用抗菌药物提供依据。方法采用K-B法和E-test法对137株肺炎链球菌进行药敏试验,用K-B法测定耐红霉素菌株的耐药表型,并分析药敏结果。结果 137株肺炎链球菌对红霉素、复方磺胺甲口恶唑的耐药率较高,分别为94.2%(129/137)和74.5%(102/137),且有逐年升高的趋势。129株红霉素耐药株中,内在型耐药(cMLSB)占70.5%,诱导型耐药(iMLSB)占19.4%,M型耐药占10.1%。红霉素耐药株对克林霉素、复方磺胺甲口恶唑共同耐药率及多重耐药率分别为66.7%、74.4%、60.5%,显著高于红霉素敏感组,差异有统计学意义(P<0.05)。结论 2009～2011年武汉大学人民医院分离的肺炎链球菌对红霉素耐药率较高,对克林霉素及复方磺胺甲口恶唑的耐药率呈逐年上升趋势,尤其是儿童对这两种抗菌药物的耐药性明显高于成人,耐药表型以cMLSB为主,且多重耐药现象严重。     

揭阳地区妊娠期妇女定植无乳链球菌分子流行特征及耐药特点

目的 了解揭阳地区妊娠期妇女无乳链球菌的分子流行特征和耐药特征,为其引起感染的防控提供依据.方法 收集揭阳地区妊娠35～37周妇女的阴道直肠拭子,对分离到的无乳链球菌进行多位点序列分型(multilocus sequence type,MLST)、分子血清分型、进行药敏试验并检测红霉素和克林霉素耐药基因(ermA、er...     

Pneumococci resistant to erythromycin.

Susceptibility to erythromycin was determined for all pneumococci isolated in one laboratory from clinical specimens between 1969 and 1977. All 4724 isolates examined prior to October 1973 were susceptible to erythromycin. From October 1973 to December 1977, 64 (0.71%) of 8995 pneumococcus isolates were resistant to erythromycin. The resistant strains were isolated from 38 patients living in six widely separated communities in Alberta. The erythromycin-resistant strains were of nine capsular types, including six that often cause bacteremic disease and five for which resistance to erythromycin has not been reported hitherto. Certain strains of type 33 and of type 15 were highly resistant, the minimum inhibitory concentration (MIC) of erythromycin being 2000 microgram/mL; these strains were also highly resistant to lincomycin and clindamycin. Resistance in strains of other types was much lower, the MIC of erythromycin being 0.6 to 20 microgram/mL, and all but one of these strains were susceptible to lincomycin and clindamycin. All the erythromycin-resistant pneumococci were suspectible to penicillin.