52株肺炎链球菌耐药性分析

目的调查分析临床标本分离到肺炎链球菌对青霉素等17种抗生素的体外抗菌活性，为临床治疗肺炎链球菌感染提供参考。方法对我院从2003年1月至2005年7月临床标本分离到的52株肺炎链球菌．用美国DADE—BEHRING公司的MICro STREP Plus链球菌药敏测定板检测肺炎链球菌对17种不同抗菌药物的MIC值。结果52株肺炎链球菌对红霉素、心环素的耐药率最高达71．2％，5株对青霉素耐药（9．6％），18株对青霉素低度耐药（34．6％），29株对青霉素敏感（55．8％），对阿奇霉素、克林霉素的耐药率为63．5％。对万古霉素、阿莫西林，棒酸、加替沙星的耐药率为0．00％。青霉素不敏感菌株对红霉素、阿奇霉素、克林霉素、氯霉素、头孢克洛、头孢峡辛的耐药率显著高于敏感株。结论肺炎链球菌对大环内酯类和凹环素耐药率高。对青霉素以低度耐药为主，喹喏酮类药物和阿莫西林，棒酸对肺炎链球菌抗菌活性较高，可作为首选药物。     

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。     

南京地区肺炎链球菌耐药情况分析

目的了解南京地区肺炎链球菌对常用抗菌药物的耐药性。方法琼脂稀释法测定14种抗菌药物对130株肺炎链球菌MIC。结果130株肺炎链球菌中，耐青霉素肺炎链球菌（PRSP，MIC≥2mg／L）占51．5％；对阿莫西林、头孢呋辛、头孢噻肟和头孢曲松的耐药率依次为6．2％、69．2％、17．7％和3．1％；对红霉素、阿奇霉素、克林霉素和四环素耐药率分别为92．3％、90．8％、89．2％和93．8％；对万古霉素、左氧氟沙星、莫西沙星、替加环素和利奈唑胺均敏感。结论南京地区肺炎链球菌对青霉素、红霉素、阿奇霉素、克林霉素、四环素和头孢呋辛等抗生素耐药性高，应注意合理选择用药。     

52株肺炎链球菌耐药性分析

目的调查分析临床标本分离到肺炎链球菌对青霉素等17种抗生素的体外抗菌活性,为临床治疗肺炎链球菌感染提供参考.方法对我院从2003年1月至2005年7月临床标本分离到的52株肺炎链球菌,用美国DADE-BEHRING公司的MICro STREP Plus链球菌药敏测定板检测肺炎链球菌对17种不同抗菌药物的MIC值.结果52株肺炎链球菌对红霉素、四环素的耐药率最高达71.2%,5株对青霉素耐药(9.6%),18株对青霉素低度耐药(34.6%),29株对青霉素敏感(55.8%),对阿奇霉素、克林霉素的耐药率为63.5%,对万古霉素、阿莫西林/棒酸、加替沙星的耐药率为0.00%.青霉素不敏感菌株对红霉素、阿奇霉素、克林霉素、氯霉素、头孢克洛、头孢呋辛的耐药率显著高于敏感株.结论肺炎链球菌对大环内酯类和四环素耐药率高,对青霉素以低度耐药为主,喹喏酮类药物和阿莫西林/棒酸刘肺炎链球菌抗菌活性较高,可作为首选药物.     

肺炎链球菌对泰利霉素等抗菌药物的体外抗菌活性

目的了解本院分离的肺炎链球菌对泰利霉素等抗菌药物的体外抗菌活性。方法对本院2005--2007年从各种临床标本收集的97株肺炎链球菌，用K—B纸片法进行药敏试验，测定这些菌株对泰利霉素等3种新近上市和其他7种临床常用抗菌药物的耐药性。结果97株肺炎链球菌对泰利霉素和利奈唑胺的敏感率均为100％，对喹奴普丁-达福普汀也未发现耐药菌株，只是有18．8％的菌株表现为中介。其他抗菌药物的耐药情况如下：对红霉素、克林霉素、万古霉素、左氧氟沙星、氯霉素和四环素的耐药率分别为60．8%、58．8％、0％、2．1％、12．8%和64．5％，对青霉素的敏感率为85．6％。结论本院尚未用于临床的3种新近上市的抗菌药物泰利霉素、利奈唑胺和喹奴普丁-达福普汀，对本院分离的肺炎链球菌有良好的体外抗菌活性。而上述细菌对红霉素、林可霉素以及四环素有较高的耐药性。     

肺炎链球菌对抗菌药物耐药机制研究进展

肺炎链球菌（Streptococcus pneumoniae）感染可导致肺炎、中耳炎、脑膜炎及败血症等。自1967年分离到首株青霉素不敏感肺炎链球菌以来．耐青霉素肺炎链球菌株逐年增加。同时,对其他8内酰胺类、大环内酯类、氟喹诺酮类、磺胺类、克林霉素和氯霉素等抗菌药物的耐药率也逐年增高。肺炎链球菌所致的高耐药率给临床治疗带来困难．引起了广泛关注。现就肺炎链球菌耐药机制进展作一综述。     

泌尿生殖道分离无乳链球菌药物敏感性分析

目的了解泌尿生殖道无乳链球菌感染及耐药状况，为临床用药提供依据。方法对临床送检的泌尿生殖道标本常规培养鉴定，并对分离出的无乳链球菌进行纸片扩散法药敏试验，对红霉素耐药、克林霉素敏感的菌株做D试验检测。结果144株无乳链球菌（尿77株，前列腺液36株，阴道分泌物31株）药敏结果显示，对万古霉素、利奈唑胺、青霉素和头孢曲松的耐药率最低，全部144株无乳链球菌中未发现耐药株；左氧氟沙星的耐药率较低，为16．2％；红霉素和克林霉素耐药率较高，分别为56．2％和53．5％。D试验阳性率为26．7％。结论从泌尿生殖道分离的无乳链球菌对青霉素、氨苄西林和头孢菌素类抗菌药物的敏感性较高，但对大环内酯类和克林霉素已有一定的耐药。     

肺炎链球茵感染的分布及耐药性分析

目的了解临床分离的肺炎链球菌的分布和耐药性,为临床合理用药提供参考。方法收集临床分离的102株肺炎链球菌,对来源分布和药物敏感性结果进行统计分析。结果临床分离到的肺炎链球菌标本主要来自痰液（87例,占85．3％）,以儿科的分离率最高（57．8％）,其次为呼吸内科（20．6％）和干部病房（11．8％）。102株肺炎链球菌对红霉素、克林霉素、复方磺胺甲嗯唑的耐药率高,分别为80．4％、83．3％、69．6％,而对氯霉素、利奈唑胺、万古霉素的耐药率低,分别为1．0％、0．0％、0．0％。青霉素不敏感的菌株与青霉素敏感的菌株相比,容易表现出更多耐药性。结论临床分离的肺炎链球菌对青霉素的耐药性呈上升趋势,红霉素、克林霉素和复方磺胺甲嗯唑已不是治疗肺炎链球菌的有效药物,第4代喹诺酮类药物有强的抗菌作用。有必要对肺炎链球菌进行耐药检测,以指导临床合理选择抗菌药物。     

肺炎链球菌84株耐药性分析

目的：了解社区获得性肺炎（CAP）感染肺炎链球菌（SP）对常用抗生素的耐药情况。方法：采集痰标本行细菌培养和药物敏感试验,并对结果进行分析。结果：84株肺炎链球菌中,青霉素耐药的肺炎链球菌（PRSP）占75％,青霉素中度敏感的肺炎链球菌（PISP）占11．36％,肺炎链球菌对红霉素、左氧氟沙星、克林霉素的耐药率分别为45．45％、46．34％、81．25％。结论：肺炎链球菌耐药情况严重。     

凝固酶阴性葡萄球菌诱导型克林霉素耐药的检测与分析

目的了解本地区凝固酶阴性葡萄球菌（CNS）对红霉素及克林霉素的耐药性和克林霉素诱导型耐药的发生率，分析红霉素耐药CNS对大环内酯类抗菌药物的耐药机制。方法用双纸片扩散法检测280株CNS对红霉素和克林霉素的耐药性，用D试验检测红霉素对克林霉素的诱导耐药率。结果280株CNS中，红霉素敏感且克林霉素敏感株占15．7％，红霉素耐药且克林霉素耐药株占37．5％，红霉素耐药且克林霉素敏感株占46．8％；红霉素耐药且克林霉素敏感的CNS中，诱导型克林霉素耐药的检出率为57．3％，其中甲氧西林耐药CNS（MRCNS）和甲氧西林敏感CNS（MSCNS）中的检出率分别为56．8％和66．7％，两者差异无统计学意义。结论临床微生物实验室应加强CNS中诱导型克林霉素耐药的检测，以指导临床合理使用抗菌药物。     

Antimicrobial activity of gatifloxacin (AM-1155, CG5501), and four other fluoroquinolones tested against 2,284 recent clinical strains of Streptococcus pneumoniae from Europe, Latin America, Canada, and the United States. The SENTRY Antimicrobial Surveillance Group (Americas and Europe).

The newer fluoroquinolones generally have greater potency against Gram-positive cocci including Streptococcus pneumoniae. In this study, we report the activity of gatifloxacin (formerly AM-1155 or CG5501) compared with penicillin, erythromycin, and four other peer drugs, tested against 2284 strains isolated in North America (Canada and United States), Latin America (six nations), and Europe in 1997. Reference broth microdilution methods were used and results were interpreted by consensus standards. Gatifloxacin demonstrated uniform potency against pneumococci across all monitored geographic areas (MIC90, 0.5 microgram/mL; > or = 99.6% of strains inhibited at < or = 1 microgram/mL). This activity was comparable to trovafloxacin (MIC90, 0.5 microgram/mL) and sparfloxacin (MIC90, 0.5 microgram/mL) and two- to four-fold greater than that of ciprofloxacin or levofloxacin. The most resistant strains to the fluoroquinolones had mutations in both par C (Ser 79-->Phe) and gyr A (Ser83-->Lys or Phe). Penicillin resistance (MIC, > or = 0.12 microgram/mL) rates varied from 27.6% in Europe to 55.7% in Latin America. Macrolide resistance was greatest in Europe and the United States. Gatifloxacin appears to be a promising new fluoroquinolone for clinical use in respiratory tract infections commonly caused by S. pneumoniae.     

Comparative in vitro activity of older and newer fluoroquinolones against respiratory tract pathogens

The aim of this study was to evaluate the antibacterial activity of older (ciprofloxacin and ofloxacin) and newer (moxifloxacin, grepafloxacin, sparfloxacin and levofloxacin) fluoroquinolones. Minimal inhibitory concentrations (MICs) were determined, according to the NCCLS guidelines, against the following respiratory tract pathogens: penicillin-susceptible and -resistant Streptococcus pneumoniae, beta-lactamase-positive and beta-lactamase-negative Haemophilus influenzae and beta-lactamase-positive Moraxella catarrhalis. In addition, we evaluated the minimal bactericidal concentrations of the same antibiotics against all the pneumococci and the haemophili. Finally, the activity of ciprofloxacin, ofloxacin, sparfloxacin and moxifloxacin against 15 pneumococci were investigated by time-kill analysis. All fluoroquinolones tested exhibited a similar, good activity against H. influenzae and M. catarrhalis. Against S. pneumoniae, irrespective of penicillin susceptibility, moxifloxacin, grepafloxacin, sparfloxacin and levofloxacin exhibited excellent activity, better than ciprofloxacin and ofloxacin. Time-kill analysis showed that 99.9% killing of all strains was obtained after 24 h with moxifloxacin at 2 x MIC, whereas other antimicrobials obtained similar results at 4 x MIC. Moxifloxacin is characterized by an improved activity against respiratory pathogens, including penicillin-resistant and -susceptible S. pneumoniae. Its activity is not influenced by beta-lactamase production. These results suggest that moxifloxacin represents a promising alternative for treatment of respiratory tract infections.     

Activity of moxifloxacin and twelve other antimicrobial agents against 216 clinical isolates of Streptococcus pneumoniae

BACKGROUND: An increased incidence of macrolide resistance in penicillin-resistant Streptococcus pneumoniae has been described. METHODS: With this in mind, 216 S. pneumoniae isolates were evaluated for their in vitro susceptibility to a new fluoroquinolone, moxifloxacin, which was compared with penicillin, amoxicillin, cefuroxime, cefotaxime, ceftriaxone, erythromycin, clarithromycin, ciprofloxacin, sparfloxacin, ofloxacin, vancomycin and teicoplanin. A broth microdilution assay was performed in cation- adjusted Mueller-Hinton broth with 5% (v/v) lysed horse blood according to NCCLS guidelines. RESULTS: Erythromycin resistance was observed in all the 22 penicillin-resistant S. pneumoniae (10.1%). All the penicillin- susceptible S. pneumoniae were susceptible to cephalosporins, whereas all the penicillin-resistant ones showed resistance to cefuroxime and only intermediate susceptibility to cefotaxime and ceftriaxone. The 216 tested strains were inhibited by sparfloxacin and moxifloxacin at concentrations of 0.12-0.5 mg/l and 0.06-0.25 mg/l, respectively, regardlesss of whether the strain was penicillin and/or erythromycin resistant. Seven penicillin-resistant strains displayed resistance to ofloxacin. All isolates were susceptible to vancomycin; teicoplanin MIC values ranged from 0.03 to 0.12 mg/l. The excellent in vitro activity of moxifloxacin against S. pneumoniae was not affected by penicillin and/or macrolides. CONCLUSION: Moxifloxacin appears to be a promising choice for the treatment of pneumococcal infections, including situations where therapeutic choices are limited due to penicillin and macrolide resistance.     

Antimicrobial resistance among clinical isolates of Streptococcus pneumoniae in the United States during 1999--2000, including a comparison of resistance rates since 1994--1995

A total of 1,531 recent clinical isolates of Streptococcus pneumoniae were collected from 33 medical centers nationwide during the winter of 1999--2000 and characterized at a central laboratory. Of these isolates, 34.2% were penicillin nonsusceptible (MIC > or = 0.12 microg/ml) and 21.5% were high-level resistant (MIC > or = 2 microg/ml). MICs to all beta-lactam antimicrobials increased as penicillin MICs increased. Resistance rates among non-beta-lactam agents were the following: macrolides, 25.2 to 25.7%; clindamycin, 8.9%; tetracycline, 16.3%; chloramphenicol, 8.3%; and trimethoprim-sulfamethoxazole (TMP-SMX), 30.3%. Resistance to non-beta-lactam agents was higher among penicillin-resistant strains than penicillin-susceptible strains; 22.4% of S. pneumoniae were multiresistant. Resistance to vancomycin and quinupristin-dalfopristin was not detected. Resistance to rifampin was 0.1%. Testing of seven fluoroquinolones resulted in the following rank order of in vitro activity: gemifloxacin > sitafloxacin > moxifloxacin > gatifloxacin > levofloxacin = ciprofloxacin > ofloxacin. For 1.4% of strains, ciprofloxacin MICs were > or = 4 microg/ml. The MIC(90)s (MICs at which 90% of isolates were inhibited) of two ketolides were 0.06 microg/ml (ABT773) and 0.12 microg/ml (telithromycin). The MIC(90) of linezolid was 2 microg/ml. Overall, antimicrobial resistance was highest among middle ear fluid and sinus isolates of S. pneumoniae; lowest resistance rates were noted with isolates from cerebrospinal fluid and blood. Resistant isolates were most often recovered from children 0 to 5 years of age and from patients in the southeastern United States. This study represents a continuation of two previous national studies, one in 1994--1995 and the other in 1997--1998. Resistance rates with S. pneumoniae have increased markedly in the United States during the past 5 years. Increases in resistance from 1994--1995 to 1999--2000 for selected antimicrobial agents were as follows: penicillin, 10.6%; erythromycin, 16.1%; tetracycline, 9.0%; TMP-SMX, 9.1%; and chloramphenicol, 4.0%, the increase in multiresistance was 13.3%. Despite awareness and prevention efforts, antimicrobial resistance with S. pneumoniae continues to increase in the United States.     

In vitro activity of levofloxacin against gram-positive bacteria

The in vitro activity of levofloxacin was investigated against 256 clinical strains of four gram-positive genera (Staphylococcus, Streptococcus, Enterococcus, and Listeria). Ofloxacin and ciprofloxacin were used as comparators. Uniform susceptibility to levofloxacin was recorded among methicillin-susceptible staphylococci, streptococci other than Streptococcus agalactiae, regardless of their being susceptible, intermediate, or resistant to penicillin (S. pneumoniae) or erythromycin (S. pyogenes and S. pneumoniae), in enterococci other than Enterococcus faecalis and E. faecium, and in Listeria monocytogenes isolates. Moreover, 1 of 22 S. agalactiae isolates and 1 of 19 E. faecium isolates was resistant, and 2 of 19 were intermediate. Resistances to levofloxacin with MIC90s in the resistance range were only observed in methicillin-resistant staphylococci and E. faecalis isolates. In any case, the MICs of ofloxacin and ciprofloxacin were usually 2-4 times higher than those of levofloxacin. In time-kill assays using three test strains (a methicillin-susceptible Staphylococcus aureus isolate, a penicillin-susceptible Streptococcus pneumoniae isolate, and an E. faecalis isolate), the bactericidal activity of levofloxacin was greater than that of ciprofloxacin. Copyright Copyright 1999 S. Karger AG, Basel.     

Antimicrobial resistance in respiratory tract Streptococcus pneumoniae isolates: results of the Canadian Respiratory Organism Susceptibility Study, 1997 to 2002

A total of 6,991 unique patient isolates of Streptococcus pneumoniae were collected from October 1997 to June 2002 from 25 medical centers in 9 of the 10 Canadian provinces. Among these isolates, 20.2% were penicillin nonsusceptible, with 14.6% being penicillin intermediate (MIC, 0.12 to 1 microg/ml) and 5.6% being penicillin resistant (MIC, > or =2 microg/ml). The proportion of high-level penicillin-resistant S. pneumoniae isolates increased from 2.4 to 13.8% over the last 3 years of the study, and the proportion of multidrug-resistant S. pneumoniae isolates increased from 2.7 to 8.8% over the 5-year period. Resistant rates (intermediate and resistant) among non-beta-lactam agents were as follows: macrolides, 9.6 to 9.9%; clindamycin, 3.8%; doxycycline, 5.5%; chloramphenicol, 3.9%; and trimethoprim-sulfamethoxazole, 19.0%. Rates of resistance to non-beta-lactam agents were higher among penicillin-resistant strains than among penicillin-susceptible strains. No resistance to vancomycin or linezolid was observed; however, 0.1% intermediate resistance to quinupristin-dalfopristin was observed. The rate of macrolide resistance (intermediate and resistant) increased from 7.9 to 11.1% over the 5 years. For the fluoroquinolones, the order of activity based on the MICs at which 50% of isolates are inhibited (MIC(50)s) and the MIC(90)s was gemifloxacin > clinafloxacin > trovafloxacin > moxifloxacin > grepafloxacin > gatifloxacin > levofloxacin > ciprofloxacin. The investigational compounds ABT-773 (MIC(90), 0.008 microg/ml), ABT-492 (MIC(90), 0.015 microg/ml), GAR-936 (tigecycline; MIC(90), 0.06 microg/ml), and BMS284756 (garenoxacin; MIC(90), 0.06 micro g/ml) displayed excellent activities. Despite decreases in the rates of antibiotic consumption in Canada over the 5-year period, the rates of both high-level penicillin-resistant and multidrug-resistant S. pneumoniae isolates are increasing in Canada.     

Comparative in vitro activity of gemifloxacin, ciprofloxacin, levofloxacin and ofloxacin in a North American surveillance study.

The in vitro activity of gemifloxacin, a new fluoroquinolone, was compared to three marketed fluoroquinolones; ciprofloxacin, levofloxacin and ofloxacin against over 4,000 recent clinical isolates covering 29 species isolated in the United States and Canada between 1997-1999. Based on MIC(90)s, gemifloxacin was the most potent fluoroquinolone tested against a majority of Gram-positive isolates: Streptococcus pneumoniae, penicillin resistant S. pneumoniae, macrolide resistant S. pneumoniae, ciprofloxacin non-susceptible (MIC > or = 4 microg/mL) S. pneumoniae, S. pyogenes, S. agalactiae, viridans streptococci, Enterococcus faecalis, methicillin susceptible Staphylococcus aureus, methicillin resistant S. aureus, S. epidermidis, S. hemolyticus, and S. saprophyticus. Against Enterobacteriaceae and aerobic non-Enterobacteriaceae Gram-negatives, gemifloxacin was usually comparable to ciprofloxacin and levofloxacin and more potent than ofloxacin for the following species: Citrobacter freundii, Enterobacter aerogenes, E. cloacae, Escherichia coli, Klebsiella oxytoca, Klebsiella pneumoniae, Morganella morganii, Proteus mirabilis, P. vulgaris, Providencia stuartii, Serratia marcescens, Acinetobacter lwoffii, A. baumannii, Burkholderia cepacia, Haemophilus influenzae, H. parainfluenzae, Moraxella catarrhalis, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia. Gemifloxacin was generally 16-64 fold more potent than the other fluoroquinolones tested against Gram-positive organisms and retains excellent activity comparable with ciprofloxacin and levofloxacin against a majority of Gram-negative pathogens.     

In vitro activity of telithromycin against respiratory tract pathogens in comparison with other antimicrobial agents

This study was done to evaluate the in vitro activity of a new ketolide telithromycin in comparison with clarithromycin, erythromycin, moxifloxacin and levofloxacin against Streptococcus pneumoniae (n = 67), Haemophilus influenzae (n = 139), and Moraxella catarrhalis (n = 46)collected between January and June 2003 in Hong Kong. Among the H. influenzae isolates, 25.2% produced beta-lactamase, while 97.8% of M. catarrhalis isolates produced beta-lactamase. Half of the S. pneumoniae isolates were nonsusceptible to penicillin, and 90.9% of these strains were resistant to clarithromycin and erythromycin. One (1.5%) S. pneumoniae strain was resistant to levofloxacin (MIC = 8 mg/l) and all isolates were sensitive to moxifloxacin and telithromycin with MIC <1 mg/l. H. influenzae isolates were sensitive to all fluoroquinolones tested and 2.2% of H. influenzae were resistant to clarithromycin. M. catarrhalis isolates were sensitive except 1 strain which was resistant to levofloxacin (MIC = 4 mg/l) and moxifloxacin (8 mg/l). All M. catarrhalis strains were sensitive to telithromycin with MIC90 = 0.5 mg/l. Telithromycin demonstrated high activity and no resistance was found in all these major respiratory tract pathogens.     

Macrolide-resistant Streptococcus pneumoniae and Streptococcus pyogenes in the pediatric population in Germany during 2000-2001

In a nationwide study in Germany covering 13 clinical microbiology laboratories, a total of 307 Streptococcus pyogenes (mainly pharyngitis) and 333 Streptococcus pneumoniae (respiratory tract infections) strains were collected from outpatients less than 16 years of age. The MICs of penicillin G, amoxicillin, cefotaxime, erythromycin A, clindamycin, levofloxacin, and telithromycin were determined by the microdilution method. In S. pyogenes isolates, resistance rates were as follows: penicillin, 0%; erythromycin A, 13.7%; and levofloxacin, 0%. Telithromycin showed good activity against S. pyogenes isolates (MIC(90) = 0.25 micro g/ml; MIC range, 0.016 to 16 micro g/ml). Three strains were found to be telithromycin-resistant (MIC >/= 4 micro g/ml). Erythromycin-resistant strains were characterized for the underlying resistance genotype, with 40.5% having the efflux type mef(A), 38.1% having the erm(A), and 9.5% having the erm(B) genotypes. emm typing of macrolide-resistant S. pyogenes isolates showed emm types 4 (45.2%), 77 (26.2%), and 12 (11.9%) to be predominant. In S. pneumoniae, resistance rates were as follows: penicillin intermediate, 7.5%; penicillin resistant, 0%; erythromycin A, 17.4%; and levofloxacin, 0%. Telithromycin was highly active against pneumococcal isolates (MIC(90) 相似文献