广州地区肺炎住院患儿感染肺炎链球菌的血清型分布及耐药性研究

目的了解广州地区肺炎住院的患儿感染肺炎链球菌的耐药性及血清型分布情况。方法用吸痰法采集患儿痰标本进行涂片，革兰氏染色镜检，合格痰标本划线接种血平板，用E-test法检测分离到的肺炎链球菌对青霉素、阿莫西林、头孢曲松、头孢呋辛、亚胺培南、氧氟沙星、万古霉素、红霉素和克林霉素9种药物的耐药性，采用K-B法检测四环素、复方新诺明的耐药性，并采用荚膜肿胀技术对分离到的79株肺炎链球菌进行血清分型。结果79株肺炎链球菌中青霉素耐药肺炎链球菌（PRSP）11．4％，青霉素中介肺炎链球菌（PISP）77．2％，青霉素敏感肺炎链球菌（PSSP）11．4％，对红霉素、克林霉素的耐药率分别为100％和93．7％，对阿莫西林、氧氟沙星、万古霉素的耐药率均为0，对头孢曲松、头孢呋辛、亚胺培南的耐药率分别为3．8％、72．2％、2．5％。79株肺炎链球菌中只有1株PSSP仅对红霉素耐药．78株肺炎链球菌对两种以上药物耐药．多重耐药率为98．7％（78／79），同时对克林霉素、红霉素、四环素、复方新诺明耐药的菌株65株，占82．3％（65／79）。79株肺炎链球菌血清型分别为19F（70．9％），23F（16．5％），6B（5．1％），4（2．5％），15B（2．5％），不能分型（2．5％），7价疫苗涵盖率为94．9％（75／79）。结论广州地区肺炎住院患儿肺炎链球菌对大环内脂类抗生素红霉素和林可酰胺类抗生素克林霉素耐药情况严重，对二代头孢菌素头孢呋辛耐药率居高，临床治疗儿童肺炎链球菌感染的肺炎应首选阿莫西林和三代头孢菌素。7价疫苗覆盖率高。预防儿童肺炎链球菌感染所致的肺炎，采用7价疫苗可以达到很好效果。     

上颌窦炎及咽炎患者肺炎链球菌带菌及耐药性调查

目的调查急慢性上颌窦炎及咽炎患者肺炎链球菌带菌及耐药情况. 方法用E-test法及纸片扩散法测定耐药情况. 结果 86株肺炎链球菌中,对青霉素敏感64株(74.4%),低度耐药18株(20.9%),高度耐药4株(4.7%),青霉素耐药菌株对红霉素、氯霉素、复方新诺明及四环素的耐药率比青霉素敏感株高,所有菌株对万古霉素敏感. 结论了解细菌耐药性的变化是合理应用抗生素的重要依据.     

肺炎链球菌青霉素结合蛋白基因pbp2x新的变异与青霉素及头孢噻肟耐药

目的 调查研究肺炎链球菌临床分离株的pbp2x基因和氨基酸序列的变异特点,探讨本地区的肺炎链球菌对青霉素及头孢噻肟的耐药机制.方法 2006年1月-2007年2月收集肺炎链球菌临床分离株34株,进行青霉素及头孢噻肟药敏试验,对青霉素不敏感的肺炎链球菌(PNSP)的青霉素结合蛋白pbp2x基因进行PCR扩增和测序,并进行BLAST分析.结果 有12株PNSP(青霉素及头孢噻肟MIC≥0.5 mg/L)发生了2个重要位点的氨基酸的替换:第一个保守基序STMK内Thr338→Ala及第三个保守基序KSG之前的Leu546→Val氨基酸替换.另外,菌株15发生了第二个保守基序SSN之前的His394→Leu氨基酸替换,而且本研究首次发现了紧邻第一个保守基序STMK后,Met342→Ile位点的氨基酸替换.有17个菌株的pbp2x基因的核苷酸及氨基酸序列出现了新的变异,已向GenBank提交,获得序列号:EU044831、EU089706-EU089709、EU106881-EU106884、EU124672.结论 本地区大多数PNSP的pbp2x核苷酸及氨基酸变异序列高度相似,提示肺炎链球菌对青霉素及头孢噻肟的耐药与pbp2x基因变异相关.     

2499例肺炎克雷伯菌临床分布及耐药性分析

目的分析肺炎克雷伯菌耐药性趋势,指导临床合理用药。方法对医院2 499例临床送验标本分离出的肺炎克雷伯菌耐药性进行统计分析。结果标本来源以痰液、尿液和血液居前3位,分别占比52.78%、12.28%、10.04%。肺炎克雷伯菌对青霉素类、头孢类抗菌药物耐药率高于80%;对碳青霉烯类抗菌药物亚胺培南耐药率有增长趋势;对替甲环素和厄他培南均高度敏感。2 499例多重耐药的肺炎克雷伯菌检出率分别为24.45%,多重耐药的肺炎克雷伯菌检出率呈上升趋势。结论针对肺炎克雷伯菌耐药性变迁,及时采取抗菌药物预警指导,合理使用抗菌药物,有效控制繁殖耐药菌产生,降低耐药率。     

murM基因变异与肺炎链球菌青霉素高度耐药及头孢曲松耐药的相关性

目的　研究肺炎链球菌murM基因变异与青霉素及头孢曲松耐药的相关性。方法　应用PCR技术扩增肺炎链球菌murM基因并进行基因测序。选取肺炎链球菌株 5 5株 ,包括青霉素敏感株 10株 (MIC≤ 0 .0 6 μg/ml) ;青霉素耐药株 4 5株 ,其中低水平耐药 10株 (MIC 0 .12～ 1μg /ml) ,高水平耐药 35株 (MIC≥ 2 μg/ml) ,在青霉素高水平耐药菌株中 ,对头孢曲松耐药 13株 (MIC≥ 2 μg/ml)。用敏感株R36AmurM基因序列作为比较标准。结果　 5 5株肺炎链球菌murM基因PCR产物测序结果 ,16株murM基因发生显著变异 (变异率≥ 3% ) ,1株青霉素MIC 3μg/ml、头孢曲松MIC 2 μg/ml的菌株 ,其murM基因变异率 3.4 % ;15株青霉素MIC≥ 8μg/ml或头孢曲松MIC≥ 2 μg/ml的菌株 ,murM基因变异率达 10 % ,呈嵌合式变异。murM基因变异与肺炎链球菌青霉素及头孢曲松MIC显著相关 (χ2 =36 .5 32 ,P <0 .0 1;χ2 =37.116 ,P <0 .0 1)。结论　肺炎链球菌murM基因变异与青霉素高度耐药 (MIC≥8μg/ml)及头孢曲松耐药 (MIC≥ 2 μg/ml)有显著的相关性。     

上颌窦炎及咽炎患者肺炎链球菌带菌及耐药性调查

目的 调查急慢性上颌窦炎及咽炎患者肺炎链球菌带菌及耐药情况。方法 用E—test法及纸片扩散法测定耐药情况．结果 86株肺炎链球菌中，对青霉素敏感64株(74.4％)，低度耐药18株(20．9％)，高度耐药4株(4．7％)，青霉素耐药菌株对红霉索、氯霉素、复方新诺明及四环素的耐药率比青霉素敏感株高，所有菌株对万古霉素敏感．结论 了解细菌耐药性的变化是合理应用抗生素的重要依据。     

引起儿童上呼吸道感染的肺炎链球菌的药敏分析

目的 分析引起儿童上呼吸道感染的肺炎链球菌的分布特点及耐药特征.方法 利用全自动微生物鉴定系统VITEK-2对儿童患者分离的菌株进行鉴定和药敏试验.结果 药敏结果分析显示肺炎链球菌对青霉素耐药率高达69.1%,同时,对复方新诺明、红霉素、四环素的耐药率也较高.结论 肺炎链球菌引起儿童上呼吸道感染的耐药情况较严重,并且表现为多重耐药性,今后临床要注意合理使用抗生素.     

肺炎链球菌的耐药性和pbp2b基因扩增产物图谱的相关性

目的 了解肺炎链球菌对青霉素和其它抗生素的耐药情况；对40株青霉素敏感菌株和30株青霉素不敏感菌株进行pbp2b基因扩增产物RFLP图谱相关性研究。方法 采用肉汤稀释法、E-试验和K-B纸片法进行抗生素药物敏感试验；通过用特异性引物pF和pR对肺炎链球菌进行PCR扩增，并对扩增产物进行限制性内切酶HaeⅢ消化反应。结果 肺炎链球菌对青霉素的不敏感率为9．9％～14．6％；40株青霉素敏感菌株(MICs≤0．094μg/ml)中的39株(97．5％)为s1、s2和s3三种之一，1株为r1；30株青霉素不敏感菌株(MICs≥0．12μg/ml)中的26株(86．7％)为r1-16六种之一，其余4株为s1。结论 青霉素和β-内酰胺酶类抗生素对北京地区的肺炎链球菌具有活性；肺炎链球菌的耐药性和pbp2b基因扩增产物图谱之间有相关性。     

广州地区儿童急性呼吸道感染鼻咽部常见病原菌及其耐药性分析

目的了解儿童急性呼吸道感染(ARTIS)鼻咽部常见的病原菌及其耐药性.方法对285例取鼻咽拭子进行培养,分离鉴定病原菌,同时对肺炎链球菌和流感嗜血杆菌(Hi)进行耐药性监测.结果 285例中共检出病原菌161株,肺炎链球菌、流感嗜血杆菌、卡他莫拉氏菌、金黄色葡萄球菌的分离率分别为20.4%、16.5%、13.0%、6.7%.肺炎链球菌对青霉素耐药率高达57.5%,同时对非β-内酰胺类抗生素复方新诺明、四环素、红霉素的耐药率已高达79.2%～89.5%,对头孢曲松、阿莫西林/棒酸尚具有较好的敏感性(85.1%～93.3%).Hi对氨苄西林的耐药率为13.3%,对头孢克洛、头孢曲松、头孢呋新、阿莫西林/棒酸均有很好的敏感性(96.4%～100%),对四环素、复方新诺明的耐药范围分别为25.3%～56.6%.结论肺炎链球菌、流感嗜血杆菌、卡他莫拉氏菌和金黄色葡萄球菌是广州地区儿童急性呼吸道感染的常见病原菌.肺炎链球菌和流感嗜血杆菌耐药形势严峻,抗生素合理应用尤为重要.     

肺炎链球菌的耐药基因及其分子生物学检测

目的 肺炎链球菌对β-内酰胺类,大环内酯类抗生素的耐药率在世界各地以较快速度上升,其流行趋势已引起医学界的普遍关注,但不同地区差异较大.肺炎链球菌的β-内酰胺耐药性主要由青霉素结合蛋白变异所致,非pbp基因突变也会导致β-内酰胺耐药性,大环内酯耐药性肺炎链球菌的耐药表型MLS型,M型分别由耐药基因ermB和mefA介导.分子生物学方法的应用使肺炎链球菌耐药性的发生得到较全面的阐述,同时对耐药基因的检测也更快速和准确.     

Evaluation of the E-test for routine testing of the susceptibility of Streptococcus pneumoniae to benzylpenicillin, amoxicillin and cefotaxime

Objective: To study the routine use of the E-test for susceptibility testing of penicillin-resistant Streptococcus pneumoniae.
Methods: A multicenter study of penicillin-resistant S. pneumoniae (PRSP) was carried out in Brittany, France (10 general hospitals, and two university hospitals including a coordinating center). Each hospital detected PRSP by the oxacillin (5-μg) disk method and determined the MICs of penicillin G, amoxicillin and cefotaxime by the E-test under routine conditions. All the PRSP strains were collected in a coordinating center and the MICs were checked by the agar dilution method. The classifications obtained from the MICs determined by the E-test and by the reference method were compared.
Results: Between 1 July 1993 and 30 June 1994, 128 PRSP strains were collected. Agreement within 1 log₂ dilution was obtained for only 62% of strains with benzylpenicillin, 72.5% with amoxicillin and 76% with cefotaxime. These data are well below published values. In addition, 52% of the strains found to be penicillin-resistant by the reference technique were of intermediate resistance according to the E-test. There were major differences in the quality of the results obtained by the participating laboratories.
Conclusions: There are problems of standardization in the routine use of the E-test. Microbiologists should therefore take particular care when performing the test and when reading the results, and ensure that reference strains are included in the assay.     

In vivo efficacy of cefotaxime and amoxicillin against penicillin-susceptible, penicillin-resistant and penicillin-cephalosporin-resistant strains of Streptococcus pneumoniae in a mouse pneumonia model

Objective: To compare cefotaxime (CTX) to amoxicillin (AMO) (usually considered the definitive therapy for penicillinsusceptible Streptococcus pneumoniae infections) in an immunocompromised mouse pneumonia model.
Methods: Three S. pneumoniae clinical isolates were used: two serotype 19 strains, a penicillin-susceptible (P^s) strain (penicillin MIC = 0.03 μ/mL) and a highly penicillin-resistant (P^r) strain (penicillin MIC = 4 μ/mL), and one serotype 23F strain, a penicillin-cephalosporin-resistant (CFTR) strain (CTX MIC = 4 μ/mL).
Results: CTX activity in this mouse model of pneumonia induced by the highly penicillin-resistant strain of S. pneumoniae was lower than expected from its low MIC against this organism. Furthermore, AMO had greater efficacy than CTX against a CFTR S. pneumoniae strain.
Conclusion: Our data suggest that there is no major difference in the in vivo efficacy of the two agents, cefotaxime and amoxicillin, against penicillin-resistant and penicillin-cephalosporin-resistant S. pneumoniae.     

Antimicrobial susceptibility of invasive isolates of Streptococcus pneumoniae in Ireland

Between January 1999 and June 2002, 646 invasive isolates of Streptococcus pneumoniae were collected in Ireland. MICs of penicillin, ciprofloxacin, cefotaxime, moxifloxacin and linezolid were determined by Etest methodology. Eighty-seven (13.5%) isolates showed intermediate resistance to penicillin, while seven (1.1%) showed high-level resistance. Eighty-seven (13.5%) isolates were resistant to erythromycin, but all isolates were susceptible to cefotaxime, moxifloxacin and linezolid. The prevalence of pneumococcal isolates non-susceptible to penicillin in Ireland is worryingly high, but currently there are alternative agents available to treat invasive infection.     

Invasive pneumococcal infections: a clinical and microbiological analysis of 53 patients in Taiwan

Objective  To track penicillin susceptibility among Streptococcus pneumoniae causing invasive diseases and to evaluate risk factors for antibiotic resistance.
Methods  A retrospective study was performed in a medical center of all patients with invasive pneumococcal infections based on positive microbiological findings, confirmed by appropriate clinical and laboratory findings. MICs of penicillin and ceftriaxone were determined and interpreted by NCCLS methodology.
Results  Fifty-three episodes of invasive S. pneumoniae infections (ISPI) among 22 children and 31 adults were identified. The disease patterns of ISPI were similar between children and adults, and the most common modes were pneumonia (70%) and primary bacteremia (23%). The rate of penicillin-nonsusceptible S. pneumoniae (PNSP) isolated from pediatric patients was higher than that in adult patients (95.5% vs. 54.8%, P  < 0.001). This finding was correlated to prior antibiotic use that was more common in children (36.4%) than in adults (18.9%). The rate of penicillin-resistance among S. pneumoniae isolates (PRSP) was extremely high in this area: 45.5% from pediatric patients and 41.9% from adult patients. More adults (90.3%) with ISPI had major underlying diseases than children (4.5%). This may explain why adult patients tended to run an unfavorable outcome (mortality rate, 51.6% and 4.5% in adults and children, respectively), although most of the cases with empyema were children. None of the patients enrolled in this study received pneumococcal vaccination.
Conclusion  We suggest that vaccines be administered for young children and the elderly with major underlying diseases to prevent ISPI.     

Pneumococcal acute otitis media in children

Objectives   To evaluate the clinical and laboratory findings of Streptococcus pneumoniae acute otitis media in children during a 1 year period.
Methods   From October 1995 to September 1996, 113 children aged 2 months to 14 years (median 18 months), with S. pneumoniae acute otitis media were studied. Susceptibility testing was performed by the Kirby-Bauer method and the E- test, and serotyping by the Quellung reaction.
Results   E- test assays detected five isolates (4.4%) to be highly resistant to penicillin and 13 (11.5%) that had intermediate resistance. All isolates were found to be susceptible to vancomycin, rifampicin and cefotaxime. In total, 25 isolates (22.1%) were resistant to one or more drugs. Fifty per cent of the penicillin-resistant or intermediately resistant S. pneumoniae isolates were resistant to multiple drugs, whereas only 2.1% of the penicillin-susceptible isolates were resistant to multiple drugs. The predominating serogroups of the isolates with reduced susceptibility to penicillin were the 19 (61.1%), 9 (16.7%), 23 (11.1%), 6 (5.5%) and 14 (5.5%) whereas those of the susceptible isolates were the 19 (26.3%), 14 (13.7%), 3 (11.6%), 6 (11.6%), 9 (8.4%), 1 (5.3%) and 12 (5.3%).
Conclusions   Streptococcus pneumoniae isolates from children with acute otitis media were penicillin-insensitive in 15.9%. The multiresistant S. pneumoniae isolates belonged to serogroups: 19 (45.4%), 9 (27.3%), 6 (18.2%) and 23 (9.1%).     

广州地区老年人肺炎链球菌临床分离株的青霉素耐药研究与分子分型

目的调查广州地区老年患者肺炎链球菌分离株对青霉素的敏感性，并分析其亲缘关系。方法K—B纸片法对33株分离自老年住院病人的肺炎链球菌进行青霉素药敏试验；应用PCR技术检测青霉素结合蛋白基因pbp1a，pbp2x，pbp2b；用盒式PCR（BOX—PCR）分析菌株间亲缘关系。用多位点测序分型技术（multilocus sequence typing，MLST）检测青霉素耐药菌株的分子分型。结果青霉素的耐药率为3．03％（1／33）：用PCR方法鉴定PSSP的准确率为68．75％；BOX-PCR可将这33株肺炎链球菌分为21型。MIST分型显示，青霉素耐药菌株属ST271型。结论广州地区老年患者肺炎链球菌对青霉素耐药率较低．用PCR方法检测PSSP有一定的可行性。BOX—PCR显示了较高的分辨率，能快速可靠地检测菌株间的亲缘关系。广州地区流行的耐药克隆与Taiwan^19F-14株同源。     

Epidemiology of penicillin resistance in Streptococcus pneumoniae isolates in Kayseri, Turkey

Objective   To determine the penicillin resistance and serotype distribution of Streptococcus pneumoniae strains and to identify clonal relationships of isolates resistant to penicillin by means of pulsed-field gel electrophoresis (PFGE).
Methods   In total, 193 S . pneumoniae strains were isolated from clinical specimens between November 1997 and January 2000. Susceptibility testing was carried out by E test, and serotyping by the Quellung reaction. Clonal relationship was analyzed by using PFGE with sma I endonuclease.
Results   Of the S. pneumoniae isolates, 23% were intermediately resistant to penicillin. There were no high-level resistant pneumococci. The majority of isolates intermediately resistant to penicillin were of serogroups/serotypes 19, 23, 14 and 1, in descending order of frequency. There were eight major clones in strains intermediately resistant to penicillin. It was seen that serogroups in the 23-valent polysaccharide vaccine, 7-valent, 9-valent, and 11-valent vaccine formulations caused 92%, 75%, 78% and 87% of pneumococcal diseases in our region, respectively.
Conclusion   Penicillin resistance in S. pneumoniae is relatively uncommon in Kayseri. All vaccine formulations can prevent the majority of pneumococcal diseases, and there is genetic heterogeneity in intermediately penicillin-resistant pneumococci in this region.     

Antimicrobial resistance in invasive and colonising Streptococcus pneumoniae in North India

The present study was done to detect the antibiotic resistance in S. pneumoniae. One hundred twenty S. pneumoniae isolates from clinical specimens and 50 from nasopharyngeal sites were subjected to antimicrobial susceptibility testing by Kirby Bauer disk diffusion method and minimum inhibitory concentration (MIC) determination for penicillin and cefotaxime non-susceptible isolates. A total of 22 isolates (18.3%) from clinical sites and eight (16%) from nasopharyngeal sites showed decreased susceptibility to penicillin by oxacillin disk diffusion test. MICs of 26 of these resistant strains ranged from 0.12-1 microg/mL (intermediate resistance) by broth dilution and E test. Only four isolates, two from sputum and two from nasopharyngeal swabs, showed MIC of 2 microg/mL (complete resistance). However, MIC of two cefotaxime resistant isolates (by disk diffusion) was in the susceptible range (0.5 microg/mL). Highest antimicrobial resistance was seen to cotrimoxazole (55.2%) and tetracycline (61.2%). Antimicrobial resistance to cotrimoxazole and tetracycline was much more in clinical isolates than colonizing isolates. Multi-drug resistant phenotype was detected in 76.9% (20 of 26) of isolates that were intermediately sensitive to penicillin and 50% (2 of 4) of penicillin resistant isolates (co-resistant to tetracycline and cotrimoxazole). Routine screening for antibiotic susceptibility is recommended for clinical isolates of pneumococci. Strains with reduced susceptibility to penicillin should be subjected to MIC determination to detect relative resistance or true resistance as such strains are associated with increased virulence.The choice of antibiotics should be guided by the prevalence of local resistance patterns of pneumococci.