20种抗菌药物对肺炎链球菌的体外抗菌活性研究

目的：评价莫西沙星等20种常用抗菌药物对临床分离的60株肺炎链球菌的体外抗菌活性。方法：采用微量肉汤稀释法测定20种抗菌药物对肺炎链球菌的最低抑菌浓度（MIC）。结果：60株肺炎链球菌中有青霉素敏感的肺炎链球菌（PSSP）42株（71．7％）,青霉素不敏感肺炎链球菌（PNSSP）18株（28．3％）;其中,青霉素耐药的肺炎链球菌（PRSP）有2株（3．3％）。对PSSP菌株,20种抗菌药物中敏感率较高的药物有头孢曲松、头孢噻肟、加替沙星、莫西沙星、左氧氟沙星、阿莫西林／克拉维酸,敏感率均为100％;耐药率较高的药物有红霉素、罗红霉素、克拉霉素、阿奇霉素,耐药率分别为83-3％,83-3％,74．7％,74．7％。对PNSSP菌株,敏感率较高的药物有阿莫西林／克拉维酸、莫西沙星、头孢噻肟、加替沙星、左氧氟沙星,敏感率分别为100％,100％,88．8％,94．4％,94．4％;耐药率较高的药物有红霉素、克拉霉素、阿奇霉素,耐药率均为66．7％。20种抗菌药物对60株肺炎链球菌的累积抑菌百分率曲线显示莫西沙星和阿莫西林／克拉维酸的抑菌能力最强。结论：肺炎链球菌对大环内酯类、复方新诺明、磷霉素等抗菌药物的耐药率较高,第三、四代氟喹诺酮类药物（左氧氟沙星、莫西沙星、加替沙星）和阿莫西林／克拉维酸及第三代头孢菌素中的头孢噻肟、头孢曲松等对肺炎链球菌（包括PNSSP）有很好的抗菌活性,提示其可作为高度耐药肺炎链球菌感染的首选药物。     

2012-2014年痰培养肺炎链球菌耐药性分析

目的调查2012年8月—2014年6月聊城市传染病医院临床送检的痰标本中分离的60株肺炎链球菌对常用抗菌药物的耐药情况,为临床用药提供依据。方法对60株肺炎链球菌进行药敏试验,分析其对常见抗菌药物的耐药性。结果 60株肺炎链球菌对红霉素和四环素的耐药率最高,分别为98.25%和92.68%,其次为复方新诺明和青霉素,为66%和61.11%,而对喹诺酮类、氯霉素、碳青霉烯类和头孢类药物均保持较高的敏感率,60株肺炎链球菌对万古霉素、泰利霉素和利奈唑胺的敏感率均为100%。结论我院临床分离的肺炎链球菌耐药严重,对红霉素、四环素、复方新诺明和青霉素高度耐药,临床应尽量减少此类药物的经验性用药,依据药敏结果选择敏感率较高的喹诺酮类、氯霉素、碳青霉烯类、头孢类、万古霉素、泰利霉素和利奈唑胺进行治疗。     

13种抗菌药物对肺炎链球菌的体外抗菌活性分析

目的 探讨常用抗菌药物对临床分离的肺炎链球菌的体外抗菌活性.方法 用全自动微生物分析系统VITEK-2Compact对临床分离的154株肺炎链球菌进行鉴定和药敏试验.结果 药敏试验测得154株肺炎链球菌有85株（54.5%）对青霉素不敏感,其中72株（46.8%）对青霉素高度耐药,13株（8.4%）对青霉素中度耐药;测得氯霉素、美诺培南、头孢噻肟、头孢曲松、阿莫西林、复方新诺明、四环素、红霉素的耐药率分别为3.4%、16.2%、19.5%、20.8%、25.3%、68.8%、84.4%、90.9%;所有菌株对左旋氧氟沙星、莫西沙星、利奈唑胺、万古霉素敏感;135株对3种或3种以上抗生素耐药,多重耐药率为87.7%.结论 肺炎链球菌对左旋氧氟沙星、莫西沙星、利奈唑胺、万古霉素100%敏感,抗菌活性高;对氯霉素、美诺培南、头孢噻肟、头孢曲松、阿莫西林耐药率也较低,对青霉素、复方新诺明、四环素、红霉素的耐药率高,尤其是青霉素不敏感株和多重耐药菌株多见,应引起临床重视.     

调兵山地区肺炎链球菌耐药性的研究

目的研究边远山区调兵山地区的肺炎链球菌耐药情况,为该地区的医院合理使用抗菌药物治疗肺炎提供循证依据。方法在调兵山地区的铁煤总医院检验科进行标本采集,采用纸片扩散法进行抗菌药物敏感性试验,利用E-test法检测分离株对青霉素的最低抑菌浓度(MIC)。其他抗菌药物(红霉素、克林霉素、复方新诺明、万古霉素)药敏试验是采用K-B法,即测定药敏抑菌圈直径用于评价药物敏感性。结果青霉素与左氧氟沙星的药物敏感率达到100.0%。其他药物,按药物敏感率大小排序如下:四环素>克拉霉素>红霉素>阿奇霉素,其中阿奇霉素的敏感率仅18.2%,复方新诺明和克拉霉素的药物敏感率可达30%以上。结论偏远山区,少医少药,肺炎链球菌对青霉素可能依然很敏感,如果青霉素耐受,可以考虑使用左氧氟沙星。     

肺炎链球菌致儿童下呼吸道感染的药敏分析

目的分析儿童下呼吸道感染的肺炎链球菌的耐药特征,为临床用药提供参考依据。方法 2012年1月至2012年12月住院首日患儿痰液培养检出肺炎链球菌256株,利用微生物全自动鉴定系统VITEK2compact及配套肺炎链球菌药敏卡对所有菌株进行药敏分析,青霉素最低抑菌浓度检测采用E-test法,药敏结果参照2010年CLSI M100-S20版指南判读。结果 256株肺炎链球菌对青霉素、红霉素、四环素和复方新诺明的耐药率分别为43.9%、98.8%、93.3%和66.5%;对头孢曲松、头孢噻肟的耐药率为53.9%、51.6%、;对万古霉素、利奈唑胺、泰利霉素和喹诺酮类较敏感。结论儿童下呼吸道分离的肺炎链球菌红霉素、四环素和复方新诺明耐药严重,耐青霉素肺炎链球菌检出率较高,临床治疗应依据药敏试验合理选用抗菌药物。     

南昌地区肺炎链球菌耐药性分析

目的了解南昌地区肺炎链球菌耐药情况,指导临床合理使用抗生素。方法用琼脂稀释法对临床分离的100株肺炎链球菌进行青霉素等12种抗菌药物最低抑菌浓度（M IC）的测定。结果肺炎链球菌对青霉素的不敏感率为57.0%、,其中高度耐药率25.0%,中度耐药率32.0%;头孢呋辛耐药率为38.0%,头孢噻肟、头孢曲松、氯霉素、左氧氟沙星的耐药率分别为12.0%、17.0%、20.0%和7.0%。对红霉素、阿奇霉素、四环素、复方新诺明、克林霉素有较高耐药率,分别为86.0%、90.0%、89.0%、86.0%和90.0%,未检出对万古霉素耐药的菌珠。结论南昌地区肺炎链球菌耐药严重,且多为多重耐药株,临床应合理选择用药。     

192株肺炎链球菌对新喹诺酮体外耐药性测定

目的:调查192株肺炎链球菌对青霉素、红霉素和环丙沙星等的耐药现状,并与新喹诺酮类进行比较.方法:根据美国国家临床实验室标准委员会(NCCLS)标准使用微量肉汤稀释法检测192株肺炎链球菌对青霉素、红霉素、克林霉素和喹诺酮类抗菌药物的最低抑菌浓度(MIC).结果:肺炎链球菌对青霉素的耐药率(中介率+耐药率)已达42.7%,对红霉素的耐药率为77.6%,克林霉素、白霉素、环丙沙星的耐药率分别为66.7%、65.6%、57.3%,新喹诺酮类抗菌药物对之有较好的抗菌活性,敏感率皆大于90%,与是否对青霉素、红霉素耐药无关.结论:在我国,肺炎链球菌对青霉素、红霉素的耐药率较高,新喹诺酮类抗生素有较好的抗菌活性.     

192株肺炎链球菌对新喹诺酮体外耐药性测定

目的调查192株肺炎链球菌对青霉素、红霉素和环丙沙星等的耐药现状,并与新喹诺酮类进行比较.方法根据美国国家临床实验室标准委员会(NCCLS)标准使用微量肉汤稀释法检测192株肺炎链球菌对青霉素、红霉素、克林霉素和喹诺酮类抗菌药物的最低抑菌浓度(MIC).结果肺炎链球菌对青霉素的耐药率(中介率+耐药率)已达42.7%,对红霉素的耐药率为77.6%,克林霉素、白霉素、环丙沙星的耐药率分别为66.7%、65.6%、57.3%,新喹诺酮类抗菌药物对之有较好的抗菌活性,敏感率皆大于90%,与是否对青霉素、红霉素耐药无关.结论在我国,肺炎链球菌对青霉素、红霉素的耐药率较高,新喹诺酮类抗生素有较好的抗菌活性.     

湘潭市中心医院社区获得性肺炎住院患儿肺炎链球菌的耐药性研究

目的了解湘潭市中心医院因社区获得性肺炎住院的患儿肺炎链球菌(SP)的耐药情况。方法对本院2010-2011年住院患儿分离的115株SP进行分析,采用K-B纸片琼脂扩散法及浓度梯度法(E测试)检测SP对青霉素、头孢曲松、红霉素、克林霉素、左氧氟沙星、万古霉素、利奈唑胺、复方磺胺甲噁唑的耐药性。结果 115株SP中青霉素敏感肺炎链球菌(PSSP)占86.1%,青霉素中介肺炎链球菌(PISP)占7.8%,青霉素耐药肺炎链球菌(PRSP)占6.1%。SP对红霉素、克林霉素及复方磺胺甲噁唑的耐药率分别为95.6%、94.8%和73.9%,左氧氟沙星的耐药率为1.7%,头孢曲松的耐药率为6.9%,未发现对万古霉素及利奈唑胺耐药的SP菌株。结论本院分离的SP对儿科常用抗生素青霉素及头孢曲松钠仍高度敏感,但对大环内酯类抗生素红霉素、林可酰胺类抗生素克林霉素耐药情况严重。     

204株肺炎链球菌的耐药性分析

目的了解襄樊市东风公司襄樊医院肺炎链球菌分布和耐药情况。方法应用K-B纸片扩散法检测对襄樊市东风公司襄樊医院2006年7月至2009年6月从临床分离的204株肺炎链球菌对青霉素等8种抗生素的敏感度,用E-test法检测对苯唑西林耐药的肺炎链球菌青霉素的MIC值。结果青霉素的耐药呈上升趋势,尤其是2008年7月至2009年6月。肺炎链球菌对克林霉素、红霉素、四环素的耐药性较高,分别为90.2%、83.3%、89.2%;对青霉素的耐药率为52.5%,对头孢噻肟的耐药率为15.7%;对氯霉素、氧氟沙星的耐药率较低,分别为23.5%、5.4%,未检出对万古霉素耐药的菌株。青霉素不敏感肺炎链球菌(PNSSP)的E-test检测结果以中介菌株为主,PNSSP的MIC值最高达到6μg/mL。结论襄樊市东风公司襄樊医院分离的肺炎链球菌耐药较为严重,耐青霉素的肺炎链球菌不断上升,有必要对其进行耐药性监测,指导临床合理选择抗菌药物。     

Prevalence of antimicrobial resistance in Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis and Streptococcus pyogenes: results of a multicentre study in Turkey

The in vitro activities of several antimicrobial agents against clinical isolates of Streptococcus pneumoniae (283), Haemophilus influenzae (272), Moraxella catarrhalis (179) and Streptococcus pyogenes (256) were determined in a multicentre study with the participation of five hospitals from four cities in Turkey. Penicillin resistance in S. pneumoniae was evaluated using the E-test and the remaining agents by disk diffusion. For S. pneumoniae overall 25.8% of the isolates were intermediately and 3.9% were highly resistant to penicillin and resistance to chloramphenicol, azithromycin and trimethoprim/sulphamethoxazole (TMP/SMX) was 3.8, 2.1 and 55.4%, respectively. Seven percent of H. influenzae produced beta-lactamase and all were susceptible to cefotaxime and azithromycin; the highest rate of resistance, 23.5%, was for TMP/SMX. Eighty-one percent of M. catarrhalis isolates produced beta-lactamase, 18.4% were resistant to TMP/SMX and all were susceptible to sulbactam/ampicillin combination. Resistance to chloramphenicol and azithromycin of S. pyogenes was 2.2 and 1.9%, respectively.     

Development of macrolide-resistance and comparative activity of telithromycin in streptococci in Austria, 1996-2002

The increase detected in macrolide resistance in streptococci in various parts of the world has brought into question the usefulness of macrolides as first line therapy for respiratory tract infections. In a nationwide study, a total of 3012 Streptococcus pneumoniae and 499 Streptococcus pyogenes isolates were collected from 1996 to 2002 and tested for their susceptibility to penicillin, azithromycin, clarithromycin and telithromycin (2002 only). Penicillin-intermediate and -resistant isolates of S. pneumoniae comprised 4.9% (2.9 and 2.0%, respectively) of all isolates in 1996; macrolide resistance was also comparatively low at 3.2%. In the following years the rate of penicillin-resistant pneumococci increased steadily, reaching the 10% mark in 2002. A similar trend was recorded for the macrolides. No penicillin-resistant strain of S. pyogenes was found during the observation period. The prevalence of macrolide-resistance in S. pyogenes climbed from 4.7% in 1996 to the present rate of 7.2% (clarithromycin) and 9.4% (azithromycin). Telithromycin showed excellent activity against both S. pneumoniae and S. pyogenes with 99.8 and 100% strains sensitive, respectively.     

Antibiotic susceptibility of Streptococcus pneumoniae in New Zealand

AIMS: To determine the current antibiotic susceptibility patterns of Streptococcus pneumoniae from four centres in New Zealand. METHODS: Over a six-month period in 1997, 386 consecutive clinical isolates of S pneumoniae were collected by four laboratories (Auckland, Wellington, Hamilton and Christchurch) from general practice or inpatients. Susceptibility testing for seven antibiotics was performed by each centre using the Etest. RESULTS: Eighty-three-percent of isolates were penicillin susceptible, 12% showed intermediate resistance to penicillin and 5% were penicillin resistant. Overall, 93 and 91% of isolates were susceptible to amoxicillin/clavulanic acid and ceftriaxone, respectively. Erythromycin and tetracycline had similar rates of susceptibility (88 and 87%, respectively). Resistance to cotrimoxazole was common, with only 57% of isolates susceptible to this combination. No National Committee for Clinical Laboratory Standard (NCCLS) breakpoints were available for cefaclor to allow interpretation of the minimum inhibitory concentration data for this agent. Wellington had lower resistance rates than Auckland, Christchurch and Hamilton. Isolates from children had consistently higher resistance rates (two- to five-fold greater for beta-lactams and 1.2 to 1.3-fold for other agents) compared with isolates from adult patients. CONCLUSIONS: Resistance to multiple antibiotics among S pneumoniae is now evident in New Zealand, although rates varied between study centres. The overall rate of penicillin resistance is 5%, which is similar to that observed in many European and US cities but lower than the rates reported in badly affected areas (> 30%). These data suggest that amoxicillin (+/- clavulanic acid), erythromycin or tetracycline are appropriate agents for empirical use in less serious community acquired infections when S pneumoniae is suspected. Ceftriaxone, with or without vancomycin, should be considered in the empirical treatment of invasive, disease until sensitivities are known.     

Antimicrobial resistance of Streptococcus pneumoniae and Haemophilus influenzae in Sao Paulo, Brazil from 1996 to 2000

This study was undertaken to assess the in vitro activity of several antimicrobial agents against Brazilian isolates of Streptococcus pneumoniae and Haemophilus influenzae from 1996 to 2000. The antibiotics used were penicillin, amoxicillin/clavulanic acid (A/C), ampicillin, amoxicillin, cefaclor, cefdinir, cefixime, cefprozil, ceftriaxone, cefuroxime, azithromycin, clarithromycin, erythromycin, ciprofloxacin, levofloxacin, ofloxacin, chloramphenicol, clindamycin, doxycycline and trimethoprim/sulphamethoxazole (T/S). MICs were determined by the National Committee for Clinical Laboratory Standards (NCCLS) method and interpreted using NCCLS and PK/PD breakpoints. For S. pneumoniae 80.0% were penicillin susceptible, 18.3% intermediate, 1.7% resistant; most active agents were amoxicillin, A/C, ceftriaxone and levofloxacin; T/S was the least active agent. Beta-lactamase was produced by 13.7% of H. influenzae. All were susceptible to A/C, cefdinir, cefixime, ceftriaxone and quinolones. The least active agents were T/S and macrolides.     

Epidemiological analysis of Streptococcus pneumoniae in Gifu prefecture

Since antimicrobial resistance in Streptococcus pneumoniae become serious problem, we have conducted the epidemiological analysis of Streptococcus pneumoniae in Gifu prefecture. We have investigated the mutations of penicillin-binding protein (PBP) cording genes, the mutations of macrolide-resistant cording genes, and antimicrobial susceptibility using broth microdilution method, for 345 strains isolated from clinical specimens between May 2006 and July 2006 at 12 clinical facilities of 5 medical area. The ratio of penicillin-susceptible S. pneumoniae (gPSSP), penicillin-intermediate S. pneumoniae (gPISP), and penicillin-resistant S. pneumoniae (gPRSP), which were judged by molecular techniques, were 7.2%, 53.5%, and 39.4%, respectively. Only 1 gPSSP strain was isolated from children under three years old. There have been regional differences of the isolation rate of gPRSP between Gifu/Chuno area (55-60%) and Tono/Hida area (23-32%) in second- or third-medical facilities. The isolation rate of PBP mutation genes, pbp2x, pbp1a and pbp2b, were 92.8%, 52.5% and 53.3%, respectively. The isolation rate of macrolide-resistant cording genes, mefA only, ermB only, and both mefA and ermB, were 30%, 50% and 8%, respectively. The strains of S. pneumoniae with both mefA and ermB mutations, increased from 4% in 2002 to 8% in 2006. The antimicrobial susceptibility of S. pneumoniae to penicillin G (PCG) showed two peaks around 0.03 and 1 microg/mL, and 89% of S. pneumoniae with minimum inhibitory concentration (MIC) value 1 microg/mL was gPRSP. The MIC values of PCG against 69% strains of gPRSP distributed between 0.25 and 1 microg/mL. There have been the decreased tendency for the differences among medical facilities in penicillin resistant strains. Although cefditoren showed the most effective antimicrobial activity in oral cephems tested, there have been the strains with MIC value of over 1 microg/mL. The MIC90 of panipenem was 0.125 microg/mL, which was the best antimicrobial activity in carbapenems. The resistant rates of clarithromycin and azithromycin were 85% and 84%, respectively. The strains with the gene mutation of ermB have showed resistant to clindamycin. The MIC90 of tosufloxacin was 0.25 microg/mL, which was the best antimicrobial activity in quinolones. We have detected 4 levofloxacin highly resistant S. pneumoniae, of which MIC value was over 32 microg/mL. Also, we have encountered the episode of the spread of S. pneumoniae in one family, which was clarified by scientific approach.     

In vitro activity of gemifloxacin and contemporary oral antimicrobial agents against 27247 Gram-positive and Gram-negative aerobic isolates: a global surveillance study

This study was a multi-centre, multi-country surveillance of 27247 Gram-positive and Gram-negative isolates collected from 131 study centres in 44 countries from 1997 to 2000. MICs of gemifloxacin were compared with penicillin, amoxicillin-clavulanic acid, cefuroxime, azithromycin, clarithromycin, trimethoprim-sulphamethoxazole, ciprofloxacin, grepafloxacin and levofloxacin by broth microdilution. Penicillin resistance in Streptococcus pneumoniae was extremely high in the Middle East (65.6%), Africa (64.0%) and Asia (60.4%) and lower in North America (40.3%), Europe (36.9%) and the South Pacific (31.8%). Macrolide resistance in S. pneumoniae was highest in Asia (51.7%) but varied widely between laboratories in Europe (26.0%), North America (21.6%), the Middle East (13.7%), the South Pacific (10.6%) and Africa (10.0%). All the study quinolones were highly active against penicillin-resistant and macrolide-resistant S. pneumoniae. Overall, gemifloxacin had the lowest MIC(90) at 0.06 mg/l with MICs 4-64-fold lower than ciprofloxacin, levofloxacin and grepafloxacin against S. pneumoniae. Gemifloxacin MICs were more potent than grepafloxacin > levoflaxacin > ciproflaxin against the Gram-positive aerobes and shared comparable Gram-negative activity with ciprofloxacin and levofloxacin.     

Antibiotic resistance rates and macrolide resistance phenotypes of viridans group streptococci from the oropharynx of healthy Greek children

A total of 200 isolates of viridans group streptococci isolated from the oropharynx of healthy Greek children were studied. Vancomycin, rifampicin, fluoroquinolones and dalfopristin/quinupristin were active against all tested isolates. High level resistance to gentamicin was not seen. Intermediate and high-level penicillin resistance was present in 28.5 and 14.5% isolates, respectively, with 41.3% of the latter group, being also resistant to cefotaxime. Resistance rates to other antimicrobials were as follows - erythromycin 38.5%, clarithromycin 33.5%, clindamycin 7.5% and tetracycline 23%. Penicillin resistance occurred more frequently in Streptococcus mitis isolates, while macrolide resistance was more frequent in S. oralis. MLSB resistance phenotype M was dominant (74%) among erythromycin resistant isolates, with phenotypes IR and CR being represented by 6 and 20% of isolates, respectively.     

Clinical isolates of Streptococcus pneumoniae resistant to levofloxacin contain mutations in both gyrA and parC genes.

Thirty Streptococcus pneumoniae clinical isolates resistant to levofloxacin were analyzed for the quinolone resistance-determining DNA sequences to identify point mutations and were tested for in vitro susceptibility to multiple drug classes. Of these isolates, 29 had mutations in both gyrA and parC genes of DNA gyrase and topoisomerase IV, respectively. In GyrA, an amino acid change from Ser-81-->Phe was detected in 27 isolates and a Glu-85-->Lys change was found in the remaining three. Of the 29 isolates for which ParC data were available, Ser-79-->Tyr or Phe were the predominant mutations observed. MICs for levofloxacin were 4-16 mg/l, whereas those for moxifloxacin were 1-2 mg/l. Twenty-four (80%) isolates were susceptible to erythromycin, 25 (83%) to azithromycin, 26 (87%) to clarithromycin, 27 (90%) to clindamycin, 20 (67%) to penicillin, 21 (70%) to ceftriaxone and 30 (100%) to amoxycillin/clavulanate. These results confirm the presence of double mutations among clinical isolates of S. pneumoniae from diverse geographical regions of North America and also suggest that quinolone resistance may develop independently of resistance to other drug classes.     

TARGETed surveillance: susceptibility of Streptococcus pneumoniae isolated from community-acquired respiratory tract infections in 2003 to fluoroquinolones and other agents

We assessed antibiotic resistance in Streptococcus pneumoniae collected worldwide in 2003. Resistance to clarithromycin was the highest overall (34.1%) followed by penicillin G (22.1%). Patient age and/or country of origin had the greatest effect on susceptibility. Resistance was highest in children<6 years of age and in patients from South Africa or France. Resistance to penicillin or amoxicillin/clavulanic acid decreased in adults and was low in Germany. Fluoroquinolone resistance was very low overall, but 3.0% levofloxacin resistance (2.6% gatifloxacin and 0.4% moxifloxacin) was observed in Italy. Interestingly, many isolates with minimum inhibitory concentrations (MICs) at the top of the fluoroquinolone susceptibility breakpoints possessed single quinolone resistance-determining region (QRDR) mutations. Care should be taken when treating fluoroquinolone-susceptible isolates with a higher MIC, which are likely to harbour QRDR mutations and may become fully resistant and cause treatment failure. We concur with the conclusions of other recent studies that suggest fluoroquinolone breakpoints should be lowered to ensure these isolates are categorised as resistant. Fluoroquinolones would still remain an important alternative treatment for respiratory tract infections (albeit for adults only), with moxifloxacin being the most potent fluoroquinolone tested in this study.     

Penicillin resistant Streptococcus pneumoniae isolates in Harare, Zimbabwe

OBJECTIVE: To determine the susceptibility of Streptococcus pneumoniae isolates to penicillin and other antimicrobial drugs. DESIGN: This was a laboratory based study. SETTING: Department of Medical Laboratory Sciences, University of Zimbabwe and the Bacteriology Unit, Public Health Laboratories, Harare. SUBJECTS: 71 S. pneumoniae isolates from Parirenyatwa and Harare hospitals. MAIN OUTCOME MEASURES: Penicillin resistance, MIC of penicillin to S. pneumoniae, multi-drug resistance. RESULTS: 71 S. pneumoniae isolates were tested for their susceptibilities to penicillin G, erythromycin, tetracycline, ampicillin, ciprofloxacin and clindamycin. Five (7%) of the isolates were resistant to penicillin G and were also all resistant to erythromycin. Isolates resistant to other antibiotics were; tetracycline (4), ampicillin (3) and ciprofloxacin (2). The five isolates that were resistant to penicillin G showed resistance to two or more antibiotics. Four S. pneumoniae isolates were designated highly resistant to penicillin (MIC > or = 2 micrograms/ml) and one isolate was designated intermediate in resistance to penicillin (MIC between 0.1 and 1.0 microgram/ml). CONCLUSIONS: A low percentage of S. pneumoniae isolates were resistant to penicillin and were also resistant to erythromycin. The penicillin resistant strains showed multi-drug resistance.