肺炎链球菌红霉素相关耐药基因与耐药表型的关系

目的:了解肺炎链球菌(Streptococcuspneum oniae,SP)临床分离株红霉素耐药基因的流行状况及和耐药表型的关系。方法:对住院儿童分离到的43株肺炎链球菌进行红霉素药敏试验,并用PCR法检测与红霉素耐药相关的红霉素核糖体甲基化酶基因(ermB)、主动外排转运基因(mefA)。结果:43株肺炎链球菌红霉素药敏试验40株耐药(占93%),3株敏感。红霉素ermB基因总检出率为76.7%(33/43),mefA基因总检出率为23.3%(10/43)。3株红霉素敏感的肺炎链球菌均未检出ermB基因和mefA基因;40株红霉素耐药肺炎链球菌ermB基因和mefA基因的PCR检出率分别为82.5%(33/40)和25%(10/40)。共有35株肺炎链球菌检出ermB基因或/和mefA基因,其中单独携带ermB基因的耐药表型为25株(占71.4%);单独携带mefA基因的耐药表型2株(占5.7%);同时携带ermB基因和mefA基因的耐药表型8株(占22.9)%。结论:ermB基因和mefA基因同时表达或单独表达均可导致红霉素耐药,ermB基因表达是儿童肺炎链球菌对红霉素耐药的主要原因,mefA基因表达是造成对红霉素耐药的次要原因。红霉素已不是治疗肺炎链球菌的有效药物。     

肺炎链球菌对大环内酯-林可酰胺-链阳菌素的耐药监测及耐药机制研究

目的研究肺炎链球菌对大环内酯-林可酰胺-链阳菌素类抗菌素的耐药机制。方法K-B纸片法测定肺炎链球菌对红霉素、克林霉素、泰利霉素和喹奴普汀/达福普汀的耐药性。对全部红霉素耐药菌株和部分红霉素敏感菌株用聚合酶链反应(PCR)检测ermB和mefA基因。结果97株肺炎链球菌对红霉素、克林霉素、泰利霉素和喹奴普汀/达福普汀的耐药率分别为60.8%、58.8%、0和0。59株红霉素耐药菌株均检出ermB和/或mefA基因,其中34株(57.6%)ermB阳性,18株(30.5%)ermB和mefA同时阳性,7株(11.8%)mefA阳性。5株敏感菌株ermB和mefA基因均为阴性。结论本研究显示肺炎链球菌对泰利霉素和喹奴普汀/达福普汀高度敏感,而对红霉素和林可霉素则表现出较高的耐药性。肺炎链球菌对大环内酯-林可酰胺-链阳菌素的耐药机制以ermB基因介导的靶位改变为主。     

肺炎链球菌对抗菌药物的耐药性调查及对大环内酯类抗生素耐药机制研究

目的：调查成都地区肺炎链球菌对抗菌药物的敏感性，研究成都地区肺炎链球菌对大环内酯类抗生素耐药机制。方法：收集2001年9月-2002年9月成都地区临床分离的肺炎链球菌，测定其对13种抗菌药物的耐药性及对大环内酯类抗生素的耐药表型；用聚合酶链反应(PCR)扩增耐药基因ermB和mefA，并对ermB和mefA进行基因序列分析。结果：82株肺炎链球菌中13株对青霉素低度耐药(占15．9％),肺炎链球菌对大环内酯类抗生素和克林霉素表现出较高的耐药率，对红霉素和克林霉素耐药率分别为80．5％(66／82)和68．3％(56／82)。耐大环内酯类肺炎链球菌中,96．4％菌株表现为内在型耐药。标准菌株ATCC49619及16株红霉素敏感菌株均未检测到ermB基因及mefA基因；ermB基因和；mefA基因分别在62和11株耐红霉素肺炎链球菌中检测到，其中7株菌同时检测到ermB基因和mefA基因。所测ermB和mefA基因序列与基因库收录序列高度一致。结论：成都地区临床分离的肺炎链球菌对青霉素耐药率较低，但对大环内酯类抗生素和克林霉素耐药却非常普遍。ermB基因介导的靶位改变是成都地区肺炎链球菌对大环内酯类抗生素的主要耐药机制。     

大连地区儿童肺炎链球菌耐药及血清分型研究

目的研究大连地区住院儿童感染肺炎链球菌（SP）的耐药性及其血清分型。方法 SP菌株均从5岁以下儿童患者鼻咽抽吸物中分离。血清分型通过多重PCR方法鉴定,药敏试验通过E-test方法来判断,而耐药基因ermB及mefA/E则由PCR方法来检测。结果从2010年7月到2013年6月,共分离得到131例SP。药敏结果显示所有的131例菌株对红霉素以及克林霉素全部耐药,大约有39.8%的菌株对青霉素G不敏感,而所有的菌株则均对左氧氟沙星和万古霉素敏感。此外,有129例（98.5%）属于多种耐药菌株。血清分型结果显示本地区SP血清型以19F（28.2%）、19A（19.1%）、6B（17.6%）及23F（14.5%）为主。且在这些血清型中的SP中,青霉素不敏感肺炎链球菌（PNSP）对阿莫西林、头孢曲松及头孢噻肟的不敏感性要显著高于青霉素敏感肺炎链球菌（PSSP）（P〈0.05）。7价疫苗（PCV7）和13价疫苗（PCV13）覆盖的血清型分别占68.7%和87.8%。此外,49株（37.4%）单独携带ermB基因,而82株（62.6%）同时携带ermB和mefA/E两种耐药基因。结论大多数分离的SP对青霉素G仍然相对敏感,所有菌株对左氧氟沙星和万古霉素敏感。本地区SP血清型以19F、19A、6B及23F为主。鉴于19A血清型的高流行率,引入PCV13更能有效地预防儿童肺炎链球菌的感染和控制耐药菌株传播。     

肺炎链球菌对大环内酯类抗生素耐药情况及耐药基因研究

目的调查上海地区肺炎链球菌对红霉素的敏感度，研究肺炎链球菌对大环内酯类抗生素耐药机制。方法对中山医院57株临床分离肺炎链球菌进行红霉素药敏试验；应用聚合酶链反应（PCR）技术对上海4所医院中分离的53株红霉素耐药肺炎链球菌检测耐药基因（ermB，mefA，merE）。结果57株肺炎链球菌中12株（21．0％）敏感，3株（5．3％）中介，42株（73．7％）耐药。53株红霉素耐药肺炎链球菌中，ermB基因、mere基因、mefA基因分别在51株（96．2％）、22株（41．5％）和1株（1．9％）中检测到。其中21株（39．6％）同时检测到ermB基因和mefE基因，1株（1．9％）同时检测到ermB基因和mefA基因，1株（1．9％）未检测到ermB基因、mefE基因或mefA基因。结论上海地区肺炎链球菌对大环内酯类抗生素耐药率较高。ErmB介导的靶位改变是最常见的耐药机制，mef（特别是mefE）介导外排机制引起者也较常见。     

β溶血链球菌中诱导型克林霉素耐药的检测和分析

目的 了解β溶血链球菌对红霉素及克林霉素的耐药性,探讨红霉素对克林霉素诱导耐药的表型和基因型.方法 按CLSI推荐的K-B法测定并判读β溶血链球菌对红霉素及克林霉素的耐药性,用D试验检测红霉素诱导β溶血链球菌对克林霉素耐药的表型,并且用PCR方法确定所检测的菌株是否携带的ermB基因和mefA基因.结果 49株红霉素耐药的β溶血链球菌结果显示有35株β溶血链球菌只扩增到ermB基因,有9株只扩增到mefA基因,有3株同时扩增到ermB和mefA基因,有2株没有扩增到ermB和或mefA基因;17株红霉素耐药克林霉素敏感菌株中D试验阳性8株细菌都只扩增到ermB,D试验阴性9株细菌中都只扩增到mefA;红霉素敏感的β溶血链球菌没有扩增到ermB或mefA基因.结论 β溶血链球菌的耐药表型与基因型高度一致,临床上可用PCR方法和D试验检测,D试验检测更为简单方便,临床应该用D试验检测β溶血链球菌的iMLS型耐药.     

肺炎链球菌大环内酯类耐药表型与相关基因的关系

目的了解肺炎链球菌临床分离株红霉素耐药基因的流行情况和耐药表型的关系。方法对42株肺炎链球菌用E-试验和K-B纸片扩散法检测其对10种抗生素的敏感性;用红霉素和克林霉素双纸片协同试验确定其耐药表型;用PCR扩增这些菌株的耐药基因ermB、mefA和mefE。结果 42株肺炎链球菌中耐药基因ermB总检出率为95.2%(40/42),mefE总检出率为26.1%(11/42),未检出mefA基因。耐药基因组合ermB(+)mefE(-)和ermB(+)mefE(+)占95.2%,两者均呈cMLSB耐药表型。ermB(-)mefE(+)占4.8%(2/42),耐药表型为M型。结论耐药基因ermB导致的cMLSB耐药是大环内酯类耐药的主要原因。大环内酯类抗生素已不是治疗肺炎链球菌的有效药物。     

肺炎链球菌耐药性及分子流行病学调查

目的研究临沂地区肺炎链球菌呼吸道感染分离株的耐药性及其传播情况.方法 对肺炎链球菌分离株进行药物敏感试验和血清学分型,并结合BOX-PCR、青霉素结合蛋白基因指纹等分子生物学方法分析菌株间亲缘关系.结果 124株肺炎链球菌中红霉素不敏感菌株33株,占26.6%,其中ermB基因介导的红霉素耐药菌株21株,占63.6%,mefE基因介导的红霉素耐药菌株12株,占36.4%.青霉素敏感株(PSSP)111株,敏感率89.5%,青霉素低度耐药株(PISP)10株,发现青霉素耐药株(PRSP)3株,PSSP组中除对红霉素、克林霉素、复方磺胺甲噁唑敏感度较低外,对阿莫西林/克拉维酸,第二、三代头孢菌素,氧氟沙星,万古霉素亦敏感;而PISP组出现了对第二代头孢菌素耐药菌株,3株PRSP除对万古霉素敏感外,对其他抗菌药物均耐药.124株肺炎链球菌血清型主要为23F、3、19F、14、9V、6A、6B等;BOX-PCR谱型共35种,其中青霉素不敏感株(PNSP)有6种谱型.结论 上述肺炎链球菌呼吸道感染分离株对红霉素耐药的肺炎链球菌,其耐药机制以ermB基因介导为主,ermB基因介导的耐药水平高于mefE基因介导的耐药水平;对青霉素耐药率较低,耐二代头孢菌素肺炎链球菌对万古霉素敏感.存在青霉素耐药菌株克隆传播和耐药基因水平传播.     

β溶血链球菌中诱导型克林霉素耐药的检测和分析

目的 了解β溶血链球菌对红霉素及克林霉素的耐药性，探讨红霉素对克林霉素诱导耐药的表型和基因型。方法 按CLSI推荐的K—B法测定并判读β溶血链球菌对红霉素及克林霉素的耐药性，用D试验检测红霉素诱导β溶血链球菌对克林霉素耐药的表型．并且用PCR方法确定所检测的菌株是否携带的ermB基因和mefA基因。结果49株红霉素耐药的β溶血链球菌结果显示有35株β溶血链球菌只扩增到ermB基因，有9株只扩增到mefA基因，有3株同时扩增到ermB和mefA基因，有2株没有扩增到ermB和或mefA基因；17株红霉素耐药克林霉素敏感菌株中D试验阳性8株细菌都只扩增到ermB，D试验阴性9株细菌中都只扩增到mefA；红霉素敏感的β溶血链球菌没有扩增到ermB或mefA基因。结论 β溶血链球菌的耐药表型与基因型高度一致，临床上可用PCR方法和D试验检测，D试验检测更为简单方便．临床应该用D试验检测β溶血链球菌的iMLS型耐药。     

儿童呼吸道感染肺炎链球菌耐药状况测定及机制分析

目的　研究本地区呼吸道感染患儿鼻咽部肺炎链球菌的药物敏感性 ,初步探讨可能的耐药机制。方法　对 845例呼吸道感染患儿的鼻咽拭子进行肺炎链球菌培养、分离 ,以Kirby Bauer纸片扩散法进行药敏试验 ,以套式 -聚合酶链反应及PCR技术进行TEM基因、ermB基因和mefA基因检测 ,加DAN测序分析。结果　 845例呼吸道感染患儿分离到 3 2株肺炎链球菌 ,携带率为 3 78% ,占检出菌 2 4 8% ;分离菌株对常用抗生素耐药为青霉素 2 2 0 % ,克林霉素 66% ,红霉素、阿奇霉素、阿莫西林 /克拉维酸 63 % ,复方甲基异恶唑 5 9% ,但对氯霉素和万古霉素均敏感 ;部分菌株 β内酰胺酶基因 (TEM )、红霉素耐药基因 (甲基化酶基因ermB)表达阳性 ,但未表达红霉素耐药基因 (外排基因mefA)。结论　肺炎链球菌是本地区呼吸道感染儿童主要致病菌 ,对常用抗生素有不同程度耐药 ,部分菌株耐药机制可能是通过表达TEM基因和ermB基因实现的。     

肺炎链球菌对大环内酯类抗生素耐药机制研究

目的了解肺炎链球菌对大环内酯类抗生素的耐药机制和转座子整合酶的流行情况。方法188株红霉素耐药肺炎链球菌，用E试验和K—B纸片扩散法检测其对11种抗菌药物的敏感性；用双纸片法（红霉素和克林霉素）确定其耐药表型；用PCR扩增这些菌株的耐药基因ermB、mefa、mefE、tetM及转座子整合酶基因intTn。结果188株红霉素耐药株中耐药基因ermB总检出率为91．5％（172／188），mefE总检出率为38．3％，未检出mefA基因。97．9Yoo的红霉素耐药株中存在转座子整合酶intTn。耐药基因组合ermB（＋）mefE（-）和ermB（＋）mef（＋），占91．5％，两者均呈cMLSB耐药表型。ermB（-）mefE（＋）占8．5％，耐药表型为M型。结论我院分离的肺炎链球菌大环内酯耐药以errnB介导的cMLS。耐药表型为主。转座子可能在本地区肺炎链球菌耐药基因的水平转移和克隆播散中起重要作用。     

High proportion of pharyngeal carriers of commensal streptococci resistant to erythromycin in Spanish adults

The presence of erythromycin-resistant (ErR) commensal streptococci in the throat of 110 healthy subjects and 87 patients with pharyngitis was investigated. The resistance determinants were studied by PCR using the primers for mef and erm genes, followed by hybridization and sequencing analysis. Overall, 94.4% of the subjects carried one or more ErR strains in their pharynx. A total of 253 ErR strains was studied: 127 (50.2%) showed constitutive or inducible resistance to clindamycin (MLS(B) phenotype) and 126 (49.8%) were susceptible to clindamycin (M phenotype). In 50 subjects (25.4%) both phenotypes were detected. The ermB gene was predominant among the MLS(B) phenotype strains (97.6%). The mefA (mefA/mefE) gene was detected in 100% of the strains with the M phenotype. One Streptococcus oralis strain bearing the MLS(B) phenotype carried both mefA and ermB genes. The mefA gene from clinical isolates of Streptococcus mitis and S. oralis was transferred by conjugation to an erythromycin-susceptible Streptococcus pneumoniae strain.     

Resistance to macrolides in Streptococcus pyogenes in France in pediatric patients

A total of 1,500 recent throat isolates of Streptococcus pyogenes collected between 1996 and 1999 from children throughout France were tested for their susceptibility to erythromycin, azithromycin, josamycin, clindamycin, and streptogramin B. The erythromycin-resistant isolates were further studied for their genetic mechanism of resistance, by means of PCR. The clonality of these strains was also investigated by means of serotyping and ribotyping. In all, 6.2% of the strains were erythromycin resistant, and 3.4 and 2.8% expressed the constitutive MLS(B) and M resistance phenotypes and harbored the ermB and mefA genes, respectively; ermTR was recovered from one isolate which also harbored the ermB gene. Ten serotypes and 8 ribotypes were identified, but we identified 17 strains by combining serotyping with ribotyping. Among the eight ribotypes, the mefA gene was recovered from six clusters, one being predominant, while the ermB gene was recovered from four clusters, of which two were predominant.     

Antibiotic susceptibility according to genotype of penicillin-binding protein and macrolide resistance genes, and serotype of Streptococcus pneumoniae isolates from community-acquired pneumonia in children

OBJECTIVES: Antibiotic susceptibilities, genes mediating beta-lactam and macrolide resistance, and serotypes were analysed for strains of Streptococcus pneumoniae. METHODS: A total of 392 strains of S. pneumoniae were isolated from paediatric patients with community-acquired pneumonia between May 2002 and 2004. All strains were classified into six genotype patterns according to the mutations found in the pbp1a, pbp2x and pbp2b genes identified by PCR. These results are represented by adding 'g', indicating genotypic identification. RESULTS: Thirty-nine per cent of the isolates showed mutations in either one or two PBP genes (gPISP, where PISP stands for penicillin-intermediate resistant S. pneumoniae) and 52.3% had mutations in three genes (gPRSP, where PRSP stands for penicillin-resistant S. pneumoniae). The majority of the strains had a macrolide resistance gene: mefA, (30.6%); ermB, (48.5%); or both mefA and ermB, (7.7%). The most frequent serotypes of these strains were: 6B (23.2%), 23F (17.6%), 19F (17.3%), 14 (10.5%) and 6A (8.2%). Serotypes of the seven-valent conjugate vaccine covered 70.9% of all isolates, and 89.8% of gPRSP. Serotypes of the strains with cefotaxime MICs of > or =2 mg/L were almost all of a vaccine type. CONCLUSIONS: The results suggest that introduction of conjugate vaccines into infants and children is necessary for the prevention of pneumococcal infections in Japan.     

某地区部分医院肺炎链球菌对红霉素的耐药性与基因分析

目的 了解某地区临床分离的肺炎链球菌(SPN)对红霉素的耐药基因流行情况及与耐药表型的关系.方法 采用微量琼脂稀释法,对2008年1月至2009年12月某地区部分医院临床分离到的98株SPN对红霉素的耐药状况进行分析,并用PCR法检测与红霉素耐药基因的关系.结果 98株SPN对红霉素的药敏结果显示,耐药87株,中敏2株,敏感9株;在红霉素耐药菌株中,含有ermB基因70株,含有Mef基因18株,含有ermA基因9株.9株红霉素敏感SPN均未检出ermB基因.结论 ermB基因表达是SPN对红霉素耐药的主要原因,并同时使克林霉素耐药.红霉素已不是治疗SPN的有效药物.     

Molecular characteristics of serotype 3 Streptococcus pneumoniae isolates among community-acquired pneumonia patients in Japan

In order to understand the spread of the erythromycin-resistant serotype 3 Streptococcus pneumoniae clone in Japan, we have assessed the molecular characteristics of this clone. Among 156 S. pneumoniae isolates recovered from adults with community-acquired pneumonia between 2003 and 2005, 42 were serotype 3 and 40 were sequence type (ST) 180/Netherlands(3)-31 by multilocus sequence typing. Thirty-eight of the 40 ST 180 isolates had acquired resistance to erythromycin via the ermB gene. Although the ermB-positive ST180 clone isolates were more susceptible to penicillin and trimethoprim-sulfamethoxazole than ermB-positive non-ST180 isolates and contained a less mutated pbp1a or pbp2b gene, without a mefA gene, the ST180 clone was highly prevalent among ermB-positive isolates. Routine surveillance for the ST180 S. pneumoniae clone may soon become necessary.