肺炎链球菌对红霉素的耐药表型及耐药基因

目的　研究肺炎链球菌对红霉素的耐药表型及耐药基因。方法　根据美国临床实验室标准化委员会标准使用微量肉汤稀释法 ,检测 192株肺炎链球菌对红霉素、克林霉素、青霉素、喹诺酮类抗菌药物的最低抑菌浓度 (MIC)。应用红霉素、克林霉素、螺旋霉素纸片行三纸片扩散法 ,检测 14 8株红霉素耐药肺炎链球菌的耐药表型。应用PCR检测 14 8株红霉素耐药肺炎链球菌携带的耐药基因。结果　肺炎链球菌对青霉素的耐药率 (中介率 耐药率 )为 4 2 7% ,对红霉素、克林霉素的耐药率分别为 77 6 %、6 6 7%。 14 8株红霉素耐药株中 ,耐药基因以ermB基因 (79 1% )为主 ,耐药表型以内在型耐药 (cMLS) (85 1% )为主。携带ermB基因的肺炎链球菌 ,74 4 %的菌株对红霉素的MIC值 >16 0 μg/ml;而携带mefA基因的肺炎链球菌对红霉素的MIC值在 0 5～ 4 0 μg/ml之间。 结论肺炎链球菌对红霉素的耐药率较高 ;耐药表型以cMLS为主 ,耐药基因以ermB介导的靶位改变多见。     

上海地区儿童化脓性链球菌的红霉素耐药基因研究

目的 了解上海地区化脓性链球菌对红霉素的耐药情况及耐药基因谱的特点.方法 2004年11月至2006年6月经复旦大学附属儿科医院传染病门诊诊断为猩红热的患儿,其咽拭子培养分离获得100株化脓性链球菌.应用PCR及序列分析法检测红霉素耐药基因mefA、ermA、ermB在该批菌株中的分布规律及其与红霉素耐药性的关系.结果上海地区化脓性链球菌的红霉素耐药率为98%,克林霉素耐药率为95%,两者耐药性的一致率为97%.100株菌株中含ermB基因的化脓性链球菌94株,占所有菌株的94%,对红霉索耐药率为100%;含mefA基因的化脓性链球菌16株,占所有菌株的16%,对红霉素耐药率为100%;100株菌株中未发现ermA基因.5株菌株未发现ermB基因及mefA基因,其中2株对红霉素敏感,3株对红霉素耐药.mefA基因单独阳性的菌株仅占1%.结论上海地区化脓性链球菌对红霉奈普遍具有较高耐药率,且与克林霉素存在较严重的交叉耐药.ermB基因是决定上海地区化脓性链球菌对红霉素耐药的重要基因.     

猪链球菌9型分离株的耐药性及耐药基因分析

目的 了解猪链球菌9型(Streptococcus suis serotype 9,SS9)的耐药性和耐药基因情况。方法 采用药敏纸片扩散法检测15株SS9菌株对9类21种不同抗生素的耐药性,并通过PCR方法检测其大环内酯类及四环素类耐药基因的携带情况。结果 被检菌株对大环内酯类及林可胺类耐药率都为100%,对四环素及链霉素的耐药率都为93.3%,对头孢类、氯霉素类、阿莫西林、糖肽类以及庆大霉素较为敏感。所有菌株均耐7种及以上抗菌药物,最高可耐16种,其中以8重耐药的菌株数量最多。不同地区SS9分离株对抗生素耐药情况不同,健康猪分离株耐药情况较病猪分离株更为严重。100%的菌株具有ermB基因,93.33%的菌株具有tetO基因,表明ermB和tetO分别可能是介导SS9对大环内酯类及四环素产生耐药性的主要原因之一。结论 本研究为猪链球菌9型的预防和临床治疗、耐药性及耐药机制的研究提供了参考依据。     

长春地区猪链球菌对大环内酯和林克酰胺类耐药的分子机制研究

目的　分析长春地区猪链球菌耐大环内酯类和林克酰胺类的分子机制。方法　采用微量稀释法和双纸片扩散法分别测定相关抗生素的耐药谱和红霉素耐药型 ,并以猪链球菌的染色体DNA为模板 ,PCR扩增ermB基因和mefA/E基因 ,然后将其克隆到pMD18-T载体中 ,用双脱氧链末端终止法测定DNA序列后进行序列分析。结果　 2 2株猪链球菌的临床分离菌株均扩增出ermB基因 ,而未扩增出mefA/E基因 ;对四环素、环丙沙星和大环内酯和克林霉素有高的耐药率和耐药水平 ;红霉素的耐药型以CR型为主。同源性分析显示 ,ermB基因的差异为 36 %～ 10 0 % ,与GenBank中的肺炎链球菌、粪肠球菌等的erm基因有 98%～ 10 0 %的同源性。结论　长春地区猪链球菌对MLSB 的耐药是红霉素甲基化转移酶所介导的 ,以CR型为主的耐药 ,编码该类耐药的是ermB基因 ,并与人源及动物源性的耐药基因可能存在着广泛的交换。     

肺炎链球菌大环内酯药物耐药性及耐药基因erm、mef的检测

肺炎链球菌是引起呼吸道感染的常见菌.近年来,耐药型肺炎链球菌出现迅猛,在我国和众多亚洲国家尤为明显~([1]).肺炎链球菌对大环内酯类抗生素的耐药率迅速增加,目前已成为一个全球性问题.其中对红霉素的耐药性已成为一个严重的现象~([2]).因此,我们对52株肺炎链球菌进行了大环内酯药物(红霉素和阿奇霉素)的耐药性情况和耐药基因erm(B)、erm(TR)、mef(A)及mef,(E)的检测分析.     

耐红霉素肺炎链球菌的分子生物学研究

目的研究耐红霉素肺炎链球菌的分子生物学特点。方法社区获得性肺炎呼吸道标本分离的肺炎链球菌共45株,进行抗生素药物敏感性试验,对耐药菌株采用PCR方法检测红霉素的耐药基因ermA/ermB/mefA,同时采用脉冲场凝胶电泳技术和青霉素结合蛋白基因多态性追踪耐药菌株之间的同源性,以获得耐药菌株的分子流行病学特点。结果45株肺炎链球菌中对红霉素耐药24株,均为多耐药肺炎链球菌;青霉素耐药14株,其中11株（78.6%）同时耐红霉素。22株（92%）的红霉素耐药株为MLS表型,即同时耐克林霉素,2株为M型耐药。经PCR扩增,20株（83.3%）具有ermA/B基因,6株（25.0%）同时有erm和mef基因,2株（8.3%）只有mef基因,2株未能检测到erm或mef基因。脉冲场凝胶电泳和青霉素结合蛋白基因多态性检测未发现不同地区相同的耐药克隆株。结论erm基因编码的核糖体突变是肺炎链球菌耐红霉素的主要机制,本研究未发现不同地区相同的耐药克隆株。     

广州市香港海鸥型菌红霉素耐药性与基因分析

目的 了解广州地区香港海鸥型菌分离株对红霉素的耐药性及红霉素耐药基因的分布情况。方法 从青蛙和草鱼肠道中分离的菌株共122株,使用K-B法对香港海鸥型菌分离株进行红霉素抗生素的耐药性测定,用PCR方法检测红霉素耐药株中红霉素抗性基因ereA,ereB,ermA,ermB,ernC,MefA/E,mphA,SAT4的携带情况,并将检测阳性结果的PCR产物进行测序分析。结果 香港海鸥型菌对红霉素耐药率为28.7%,其中蛙源株耐药率为35.1%,鱼源株耐药率为25.9%。对红霉素耐药的35株菌中,蛙源株ereA基因检出率为30.8%,鱼源株没有检出ereA基因。结论 广州地区香港海鸥型菌对红霉素的耐药率较高,蛙源株对红霉素的耐药率比鱼源株高,海鸥型菌蛙源株对红霉素产生的耐药性与ereA基因相关。     

浙江省猪链球菌人源感染株的耐药检测分析

目的了解浙江省猪链球菌人源感染株在体外对抗菌药物的耐药性和耐药基因携带状况。方法收集2005年至2021年浙江省31株猪链球菌人源感染散发株, 通过微量稀释法测定15种抗菌药物对所有菌株的最低抑菌浓度, 利用聚合酶链反应检测四环素类、大环内酯类和氨基糖苷类等70种耐药基因。结果 31株菌株对头孢吡肟、头孢噻肟、头孢曲松、氯霉素、达托霉素、厄他培南、左氧氟沙星、利奈唑胺、美罗培南、青霉素、万古霉素11种抗菌药物均敏感, 敏感率达到96.8%及以上, 对四环素、克林霉素、阿奇霉素、红霉素均耐药, 特别是对四环素的耐药率达93.5%(29/31), 多重耐药株共14株(45.2%)。70种耐药基因检测中, 共检出14种(20.0%)耐药基因。耐药基因检出率高的主要为耐四环素类基因, 依次是tet(O) [58.1%(18/31)]、tet(M) [48.4%(15/31)]、tet(40) [35.5%(11/31)];其次是耐大环内酯类ermB基因[41.9%(13/31)];14株(45.2%)同时检出3种以上耐药基因, 其中8株(25.8%)检出10种耐药基因。耐药基因结果与序列分型结...     

泉州地区19F型肺炎链球菌耐药性分析及多位点序列分型研究

目的了解泉州地区临床分离株19F血清型肺炎链球菌(Streptococcus pneumoniae,SP)的耐药特征及多位点序列分型。方法 19F血清型采用多重PCR进行筛选分析,采用OP纸片法进行药敏试验测定其MIC值,采用PCR方法检测耐药基因ermB,mefE,mefA及转座子家族Tn1545转座酶基因,采用多位点序列分型(MLST)技术分析菌株序列型(ST)。结果 52株SP均表现出对利奈唑胺、替考拉宁、万古霉素的敏感;对红霉素、克林霉素、四环素、复方新诺明、青霉素G、阿莫西林、头孢噻肟、头孢吡肟、美洛培南、氯霉素、左旋氧氟沙星的耐药率分别为98.1%、98.1%、98.1%、92.3%、41.8%、38.4%、29.1%、22.6%、13.5%、9.6%、7.7%。ermB、int Tn916/Tn1545、mefE、mefA基因检出率分别为为98.1%、94.2%,75.0%、65.4%,4种耐药基因同时检出占57.7%,对红霉素、克林霉素、四环素、复方新诺明的耐药率为100%。52株SP MLST分型共分出14种STs,存在2个优势型,分别为ST271(占38.5%)和ST320(占19.2%),其中一个新的ST已被MLST数据库录入为ST10228。结论泉州地区SP耐药较为严重,且存在多重耐药,19F血清型ST271和ST320为主要流行型。     

肺炎链球菌对β-内酰胺类及大环内酯类抗生素耐药基因的研究进展

近年来,肺炎链球菌对β-内酰胺类及大环内酯类抗生素的耐药率在逐渐上升,目前关于其耐药基因的研究已引起广泛关注,现就肺炎链球菌对β-内酰胺类及大环内酯类抗生素耐药基因的研究进展作一综述.     

突变敏感性分子开关检测肺炎支原体对大环内酯类抗生素的耐药性研究

目的 应用突变敏感性分子开关检测肺炎支原体对大环内酯类抗生素的耐药性。方法 采用微量稀释法检测5种常用大环内酯类抗生素对40株Mp临床分离株的药物敏感性;建立高保真聚合酶和3'硫化修饰引物的分子开关,用分子开关进行Mp临床分离株的PCR扩增,检测其是否存在Mp 23S rRNA 2063、2064和2617 3个热点突变,并通过基因测序进一步确定是否存在点突变,分析点突变与大环内酯类抗生素敏感性之间的关系。结果 5种大环内酯类抗生素中,Mp对14元环的红霉素和克拉霉素耐药程度最高,其MIC≥128 mg/L;对15元环的大环内酯类抗生素阿奇霉素和交沙霉素相对敏感,其中交沙霉素抗Mp活性最高,其MIC≤4 mg/L。用高保真聚合酶和3'硫化修饰引物的分子开关行PCR扩增,检测出35株发生了2063位点基因突变,3株发生2064位点基因突变,未检测出2617位点突变。用基因测序检测到35株Mp发生A2063G的突变,3株发生A2064G的突变,未检测到2617位点突变,与分子开关的检测结果一致,并且2063、2064位点突变Mp株均对大环内酯类药物高度耐药。结论 分子开关可识别23S rRNA基因突变,可用于分析Mp对大环内酯类抗生素的敏感性。     

The emergence of Streptococcus pneumoniae resistant to macrolide antimicrobial agents: a 6-year population-based assessment

From 1994 through 1999, the available isolates (4148 isolates) from active population-based surveillance of invasive pneumococcal disease in metropolitan Atlanta were serotyped and were tested for antimicrobial susceptibility. Macrolide-resistant isolates were studied for the presence of ermAM (a ribosomal methylase gene), mefE (a macrolide efflux gene), and tetM (the class M tetracycline resistance gene). Macrolide resistance increased from 16% of all invasive isolates in 1994 to 32% in 1999. Of the macrolide-resistant pneumococcal isolates studied, 99% contained genomic copies of mefE or ermAM. Isolates with ermAM were mainly serotypes 6B, 23F, 14, or 19F and contained tetM; mefE-associated isolates were predominantly serotypes 14, 6A, or 19F, and most did not contain tetM. The frequency of the ermAM-mediated phenotype in invasive Streptococcus pneumoniae remained stable over the 6-year surveillance. However, the mefE-mediated phenotype increased from 9% in 1994 to 26% of all isolates in 1999 and was noted in new serotypes. By 1999, 93% of the mefE-containing strains had minimum inhibitory concentrations >/=8 microgram/mL. Dissemination of the mefE determinant accounted for the rapid increase in the rate of macrolide resistance in our S. pneumoniae population.     

Structure and dissemination of a chromosomal insertion element encoding macrolide efflux in Streptococcus pneumoniae

Macrolide resistance associated with macrolide efflux (mef) has rapidly increased in Streptococcus pneumoniae. We defined the genetic structure and dissemination of a novel mefE-containing chromosomal insertion element. The mefE gene was found on the 5' end of a 5.5- or 5.4-kb insertion designated as the macrolide efflux genetic assembly (mega), which is found in > or =4 distinct sites of the pneumococcal genome. The element was transformable and conferred macrolide resistance to susceptible S. pneumoniae. The first 2 open-reading frames (ORFs) of the element formed an operon composed of mefE and a predicted adenosine triphosphate-binding cassette homologous to msrA. Convergent to this efflux operon were 3 ORFs with homology to stress response genes of Tn5252. Mega was related to the recently described mefA-containing element Tn1207.1 but lacked the genes necessary for transposition and had unique termini and insertion sites. In metropolitan Atlanta, macrolide resistance due to mega rapidly increased in S. pneumoniae by clonal expansion and horizontally by transformation.     

Prevalence of macrolide resistance mechanisms in Streptococcus pneumoniae isolates from a multicenter antibiotic resistance surveillance study conducted in the United States in 1994-1995.

Two main mechanisms of macrolide resistance have been described in erythromycin-resistant Streptococcus pneumoniae (ERSP): a ribosomal methylase, ErmAM, and a macrolide efflux pump, MefE. In this study, we examined the prevalence of these mechanisms in 114 clinical isolates of ERSP from a 30-center study conducted in the United States between November 1994 and April 1995. The isolates were screened by polymerase chain reaction for the presence of known macrolide resistance genes. Seventy (61%) ERSP contained the macrolide efflux gene (mefE), whereas 36 isolates (32%) contained the biosomal methylase gene (ermAM). Isolates that were ermAM-positive had constitutive macrolide resistance. The minimum inhibitory concentrations (for which 90% of isolates were susceptible) of clarithromycin for the efflux-positive strains were much lower than those for the ermAM-positive strains (4 microg/mL vs. >128 microg/mL, respectively). The efflux mechanism is the predominant form of macrolide resistance in the United States.     

Characterization of macrolide resistance in Gram-positive cocci from Colombian hospitals: a countrywide surveillance.

OBJECTIVE: The characterization of macrolide resistance in Gram-positive cocci recovered from Colombian hospitals. METHODS: The resistance profiles and mechanism of macrolide resistance were investigated in isolates of Streptococcus pneumoniae (1679), Staphylococcus aureus (348), coagulase-negative staphylococci (CoNS) (175), and Enterococcus spp (123). Minimum inhibitory concentrations (MICs) for erythromycin (ERY) and clindamycin (CLI), detection of macrolide resistance genes, phenotypic characterization, and pulsed field gel electrophoresis (PFGE) of macrolide-resistant pneumococci were performed. RESULTS: Resistance to ERY and CLI was 3.3% and 2.3% for S. pneumoniae, 58% and 57% for S. aureus (94% for both compounds in methicillin-resistant Staphylococcus aureus (MRSA)), and 78.6% and 60.7% in methicillin-resistant Staphylococcus epidermidis, respectively. ERY resistance was 62% in Enterococcus faecalis and 82% in Enterococcus faecium. The MLS(B)-type accounted for 71% of S. pneumoniae and 100% of MRSA. The erm(A) gene was prevalent in MRSA, erm(B) in S. pneumoniae and enterococci, and erm(C) in CoNS isolates. Efflux pump genes (mef(A) genes) were mostly identified in S. pneumoniae (24%). The most common genotype amongst ERY-resistant pneumococci was the Spain(6B)-2 clone. CONCLUSIONS: The prevalence of macrolide resistance is low in Colombian pneumococci and high in MRSA (cMLS(B)-type).     

Analysis of the resistance gene in Streptococcus pneumoniae

Resistance genes were determinded for 81 strains of Streptococcus pneumoniae isolated from Ehime University hospital, during 2002 and 2003 by various clinical material. In penicillin-binding proteins of mutation, there were 74 strains; pbp2x mutation 23 strains (28.4%), pbp2b mutation one strain (1.2%), pbp1a + pbp2x mutations 5 strains (6.2%), pbp2x + pbp2b mutations 18 strains (22.2%) and all mutations 27 strains (33.3%). As for the result of macrolide resistance genes, there were 67 strains; mefA gene 20 strains (24.7%), ermB gene 46 strains (56.8%) and both gene one strain (1.2%). In the analysis of gyrA gene and parC gene, 3 strains (3.7%) had both gene mutations, and 26 strains (32.1%) had only parC gene mutation. There was more of an increase than before in isolates, two or more mutation strains with PBPs gene, ermB gene holding strains and the levofloxacin resistance strain. These results suggest that the gyrA gene or parC gene mutation strains hold PBPs gene mutation and macrolide resistance genes in a high rate, and there will be more drug resistance in the future.     

Streptococcus pneumoniae and Streptococcus pyogenes isolated from a paediatric population in Great Britain and Ireland: the in vitro activity of telithromcycin versus comparators

OBJECTIVES: To investigate the antimicrobial susceptibility profiles of clinical isolates of Streptococcus pneumoniae and Streptococcus pyogenes, isolated from children within Great Britain and Ireland (Northern Ireland and Eire), with particular reference to the new oral ketolide telithromycin. To determine the distribution of macrolide resistance genes within the erythromycin resistant population. METHODS: MICs were determined using NCCLS microbroth dilution methodology and macrolide resistance mechanisms were investigated using PCR. RESULTS: Penicillin susceptibility was found to be 92.6% in S. pneumoniae isolates ( n=831; 3.7% intermediate, MIC 0.12-1 mg/l, 3.7% resistant, MIC >2.0 mg/l) and 100% in S. pyogenes isolates (n=1333) 8.8% of S. pneumoniae and 2.5% of S. pyogenes isolates demonstrated erythromycin-A resistance (EryA(R)). One hundred percent of S. pneumoniae and 99.8% of S. pyogenes isolates were susceptible to telithromycin (MIC相似文献