79株肺炎链球菌的耐药性测定

目的调查北京地区肺炎链球菌对青霉素等抗生素的耐药率。方法用Ｅｔｅｓｔ及琼脂稀释法测定临床分离的７９株肺炎链球菌１５种抗生素的最低抑制浓度（ＭＩＣ）。结果Ｅｔｅｓｔ测得１０株（１２．７％）低耐青霉素（ＭＩＣ０．１２５～１μｇ／ｍｌ），１株（１．３％）高耐青霉素（ＭＩＣ４μｇ／ｍｌ）；仅１株处于头孢曲松、头孢噻肟中介范围（ＭＩＣ１μｇ／ｍｌ）．琼脂稀释法测得阿莫西林、阿莫西林／棒酸、头孢呋肟、环丙沙星、氯霉素、四环素、红霉素的耐药率分别为１．３％、１．３％、２．５％、２．５％、１６．５％、４９．４％、４０．５％，所有菌株对头孢曲松、万古霉素敏感。结论北京地区１４％的肺炎链球菌耐青霉素，耐三代头孢菌素及多重耐药株罕见。     

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。     

Streptococcus pneumoniae endophthalmitis: a study of 36 cases with special reference to antibiotic resistance and treatment options

Patients (n = 36) diagnosed with pneumococcal endophthalmitis from six Spanish hospitals between 1986 and 2004 were studied retrospectively. The diagnosis was based on clinical findings, ophthalmological examination, and isolation of Streptococcus pneumoniae from vitreous and/or aqueous humours of 19 patients (definite diagnosis), and from other ocular specimens of 17 patients (probable diagnosis). The mean (+/- SD) age was 69.3 (+/- 16.5) years (range 1.5-89 years), and 20 (55.5%) patients were male. The origin of endophthalmitis was considered exogenous for 34 (94.5%) patients. The most common predisposing factors were previous ocular surgery (n = 25, 69.4%), ocular trauma (n = 5, 13.9%), and close-to-eye radiotherapy (n = 3, 8.3%). Eleven (30.5%) patients underwent evisceration as the first therapeutic measure (primary evisceration), and evisceration was performed after antibiotic treatment failure (secondary evisceration) for six (16.7%) patients. Primary evisceration was performed more commonly (63.6%) during 1998-2004, while secondary evisceration was only performed during 1986-1997. Eighteen (50%) patients received intra-vitreous antibiotics (mainly vancomycin), and 31 (86.1%) patients were given systemic antibiotic therapy. The most frequent pneumococcal serogroups isolated were 6, 19, 9, 15 and 23. Pulsed-field gel electrophoresis analysis of 23 isolates revealed that four belonged to the international clones Spain(23F)-1, Spain(6B)-2, Spain(9V)-3 and Sweden(15A)-25. Non-susceptibility rates (i.e., intermediately-resistant and resistant) were: co-trimoxazole, 44.8%; penicillin, 33.3%; tetracycline, 31.0%; erythromycin, 21.9%; chloramphenicol, 17.9%; rifampicin, 7.4%; cefotaxime, 5.9%; and levofloxacin, 0%. Although uncommon, pneumococcal endophthalmitis is a medical emergency because of the often aggressive clinical course, poor visual outcome and need for evisceration in a large proportion of patients.     

青岛地区部分医院2005-2008年肺炎链球菌的耐药性分析

目的 监测青岛地区肺炎链球菌的耐药性,为临床合理应用抗菌药物提供依据.方法 采集青岛地区部分医院2005年1月到2008年12月门诊与住院感染患者呼吸道、血液、脑脊液等标本,培养、分离和鉴定肺炎链球菌.根据NCCLS的推荐,采用琼脂微茸稀释法测定分离出的231株肺炎链球菌对11种常用抗菌药物的耐药性,分析耐药趋势及年龄差异.结果 231株肺炎链球菌对青霉素不敏感率为23.38%[耐青霉素肺炎链球菌(PRSP):9.52%;低耐青霉素肺炎链球菌(PISP):13.85%].对头孢噻肟耐药率最低为9.96%(23/231),其次阿莫西林为12.55%(29/231).对红霉素耐药率最高为90.48%(209/231).14岁以下患者PRSP检出率为27.91%(12/43),明显高于成人的PRSP检出率5.38%(10/186).结论 本地区PRSP检出率较2004年前明显增加,并有逐年增加的趋势,肺炎链球菌的耐药性也有逐年上升的趋势.本地区对感染低耐青霉素肺炎链球菌的患者头孢噻肟、阿莫西林可为首选药物.     

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。     

Decreasing rates of resistance to penicillin, but not erythromycin, in Streptococcus pneumoniae after introduction of a policy to restrict antibiotic usage in Taiwan

A 16% decline in rates of penicillin resistance in Streptococcus pneumoniae isolates in Taiwan between 1998--1999 (25%) and 2001 (9%) was associated with a 46% decrease in total penicillin and other cephalosporin usage in 2001 compared with 1999. However, erythromycin resistance in S. pneumoniae remained high (94%), despite a 45% decrease in macrolide consumption between 1999 and 2001.     

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.     

Epidemiology of penicillin resistance in Streptococcus pneumoniae isolates in eastern France

Objective: To assess the rates of intermediate and high-level resistance to penicillin among Streptococcus pneumoniae isolates and to identify clonal relationship of isolates within the different serotypes by means of pulsed-field gel electrophoresis.
Methods: We studied all clinical isolates obtained between April 1995 and March 1996 from patients admitted to 10 hospitals in eastern France. Antibiotic susceptibility testing and serotyping were performed on all isolates. The genetic polymorphism of isolates susceptible, intermediately resistant and highly resistant to penicillin was studied by using pulsed-field gel electrophoresis with Apa I and Sma I endonucleases.
Results: The prevalence of intermediate and high-level resistance was respectively 30.3% and 9.7%. Diminished sensitivity to penicillin was mainly encountered in serotypes 6,9V, 14 and 23F. The 9V isolates from the different hospitals were genetically closely related, unlike the 23F isolates. Different levels of resistance (MICs from 0.5 to 2 mg/L) were expressed by closely related isolates. Three 9V isolates, three capsular-type 14 isolates and one non-typeable isolate were genetically closely related in studies with the two endonucleases.
Conclusions: The capsular type was not a good indicator of genetic relatedness. The level of penicillin resistance was independent of the clonal classification. Horizontal gene transfer may be the main factor determining the degree of resistance.     

Changes in antimicrobial resistance,serotypes and genotypes in Streptococcus pneumoniae over a 30-year period

Over the past three decades, antimicrobial resistance in Streptococcus pneumoniae has dramatically increased worldwide. Non-susceptibility to penicillin in S. pneumoniae was first described in Australia in 1967, and later in New Guinea (1974), South Africa (1977), and Spain (1979). Most of these strains showed resistance to multiple antibiotics and belonged to serotypes 6A, 6B, 19A, 19F, and 23F. By the late 1980s and 1990s, the emergence and rapid dissemination of antibiotic-resistant pneumococci was observed in southern and eastern Europe, North America, South America, Africa, and Asia. Great geographical variability, both in serotype distribution and in the prevalence of resistant pneumococci, has been reported. However, the highest rates of resistance to penicillin and erythromycin worldwide were found in serotypes 6B, 6A, 9V, 14, 15A, 19F, 19A, and 23F. The introduction of the seven-valent pneumococcal conjugate vaccine (PCV7) in the 2000s and a reduction in antimicrobial use were associated with a significant decline in the incidence of invasive pneumococcal infections and in rates of antibiotic resistance in the USA. However, an increase in the incidence of infections caused by non-PCV7 serotypes, especially multiresistant serotype 19A pneumococci, has been observed in many countries over the last 5 years. The dynamic character of serotypes and antibiotic resistance in S. pneumoniae should be controlled by a policy of prudent antibiotic use and by implementation of the new generation of conjugate vaccines.     

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.     

Molecular characterization of genes encoding the quinolone resistance determining regions of Malaysian Streptococcus pneumoniae strains

Genes encoding the quinolones resistance determining regions (QRDRs) in Streptococcus pneumoniae were detected by PCR and the sequence analysis was carried out to identify point mutations within these regions. The study was carried out to observe mutation patterns among S. pneumoniae strains in Malaysia. Antimicrobial susceptibility testing of 100 isolates was determined against various antibiotics, out of which 56 strains were categorised to have reduced susceptibility to ciprofloxacin (>or=2 microg/mL). These strains were subjected to PCR amplification for presence of the gyrA, parC , gyrB and parE genes. Eight representative strains with various susceptibilities to fluoroquinolones were sequenced. Two out of the eight isolates that were sequenced were shown to have a point mutation in the gyrA gene at position Ser81. The detection of mutation at codon Ser81 of the gyrA gene suggested the potential of developing fluoroquinolone resistance among S. pneumoniae isolates in Malaysia. However, further experimental work is required to confirm the involvement of this mutation in the development of fluoroquinolone resistance in Malaysia.     

The antimicrobial resistance profile of Streptococcus pneumoniae

Antibacterial resistance in pneumococci is increasing worldwide, primarily against β -lactams and macrolides. Understanding the role played by molecular determinants of resistance, transformation and competence in the evolution of Streptococcus pneumoniae is important in addressing this trend. Data from the Prospective Resistant Organism Tracking and Epidemiology for the Ketolide Telithromycin (PROTEKT) study indicate that about 40% of pneumococci display multidrug-resistant phenotypes (resistance to three or more antibiotics), with highly variable prevalence rates observed in different countries. Alterations in the structure of six penicillin-binding proteins (PBPs) have been described in S. pneumoniae (1a, 1b, 2x, 2a, 2b and 3), enabling resistance to β -lactam antibiotics. Mechanisms conferring macrolide resistance include resistance mediated through the erm (B) gene, which results in macrolide–lincosamide–streptogramin B resistance, or through the mef (A) gene, which encodes an antibiotic efflux pump. Another variant, mef (E), is also expressed in S. pneumoniae ; both mef (A) and mef (E) variants are associated with strains belonging to serotype 14. In addition to the selection pressure resulting from misuse of antibiotics, widespread vaccination programmes may contribute to changing pneumococcal epidemiology. Since the introduction of the seven-valent pneumococcal conjugate vaccine (PCV7), the rate of invasive pneumococcal disease due to PCV7 serotypes has declined significantly in many countries, but some countries have reported an increase in non-PCV7 serotypes. This phenomenon, termed 'replacement', is associated with certain pneumococcal serotypes or clones (e.g. serotype 19A). Whether novel 'vaccine escape recombinant' pneumococcal strains are emerging or changes in distribution are part of a secular cycle remains to be determined.     

Evolution of Streptococcus pneumoniae serotypes and antibiotic resistance in Belgium—update (1994–98)

Objective To follow the evolution of capsular types and resistance of Streptococcus pneumoniae , isolated from deep sites.
Methods More than 100 Belgian laboratories permanently collect S. pneumoniae strains isolated from puncture specimens (blood, cerebrospinal fluid, middle ear fluid, etc.) and forward them to the reference center in Leuven, in order to determine the capsular serogroups and types (SGTs) and their resistance.
Results From 1994 to 1998, the 5486 S. pneumoniae strains examined belonged to 39 of the 46 currently identified SGTs. The 10 most frequent SGTs accounted for 78.9% of the isolates, and 97% of all isolates belonged to SGTs included in the 23-valent vaccine. Overall mortality of patients with pneumococcal bacteremia or meningitis was 9.7%, and 23.8% in patients over 80 years. From 1994 to 1998, resistance to penicillin (P) increased from 7.6% to 14.2%, to tetracycline (T) from 14.9% to 28.0%, and to erythromycin (E) from 22.9% to 31%. Triple resistance (PTE) increased from 0.9% in 1994 to 6.6% in 1998. Five SGTs (6, 9, 14, 19 and 23) accounted for 50% of the isolates, but for > 90% of the penicillin-resistant or erythromycin-resistant isolates.
Conclusions Resistance of S. pneumoniae to penicillin, erythromycin and tetracycline is steadily increasing and is concentrated in five serotypes included in the 23-valent pneumococcal vaccine. Increasing resistance and high mortality of invasive infections are an incentive to vaccinate vulnerable groups.     

Serotyping and antibiotic resistance of Streptococcus pneumoniae isolated from pediatric infections in central Greece

Objective: To determine the distribution of serogroups/serotypes and antibiotic resistance pattern of Streptococcus pneumoniae isolated from pediatric infections in central Greece.
Methods: In total, 306 S. pneumoniae strains isolated from children, aged from 18 days to 14 years (median 18 months), during a 21-month period, from different specimen sources, were studied. Susceptibility testing was carried out by the Kirby-Bauer method and by the Etest, and serotyping by the Quellung reaction.
Results: Of the S. pneumoniae isolates, 3.9% were highly resistant to penicillin (PR), while 17.6% were intermediately resistant (IPR). PR and IPR isolates were found to be, in general, more resistant to other antibiotics than penicillin-susceptible isolates. The PR and IPR isolates belonged to the serogroup/serotypes 19, 23, 9, 6 and 14 (in descending order of frequency). The penicillin-susceptible isolates belonged to 20 different groups/serotypes, the most common being 19, 6, 14, 9, 3, 23 and 1 (in descending order of frequency). Serogroup 23 was often found to be multiresistant.
Conclusions: Resistance to penicillin in S. pneumoniae isolates is relatively low and differs according to the specimen type. All the pneumococcal serogroups/serotypes isolated from the children were found to be included in the 23-valent polysaccharide vaccine. Most of the children with a pneumococcal infection, however, were less than 2 years old and could not be protected by the existing vaccine.     

Molecular epidemiology of penicillin-non-susceptible Streptococcus pneumoniae isolates from children with invasive pneumococcal disease in Germany

A population-based nationwide surveillance of antibiotic resistance associated with invasive pneumococcal disease (IPD) in children and adolescents (aged<16 years) was performed in Germany between 1997 and 2004. In total, 1517 isolates were collected, of which 5.1% and 1.1% were intermediately- or fully-resistant, respectively, to penicillin G. During the 8-year study period, an increase in resistance to both penicillin G and erythromycin A was observed, and the frequency of isolates exhibiting reduced susceptibility to penicillin G or erythromycin A increased from 1.4% and 11.1%, respectively, in 1997, to 8.7% and 29.0%, respectively, in 2004. Among the penicillin non-susceptible pneumococcal isolates, serotypes 14 (24.5% of isolates), 23F (16.0%) and 6B (16.0%) were found most frequently. Multilocus sequence typing of 58 (62%) penicillin G non-susceptible isolates revealed that sequence type (ST) 156 (Spain9V-3 clone) and its single-locus variant ST 557 were widespread in Germany. Moreover, 17 new penicillin G non-susceptible STs were defined for the first time. The study illustrated the genetic heterogeneity of antibiotic-resistant pneumococcal isolates in Germany.     

Prevalence of penicillin and erythromycin resistance among invasive Streptococcus pneumoniae isolates reported by laboratories in the southern and eastern Mediterranean region

Information about the epidemiology of resistance in Streptococcus pneumoniae within southern and eastern countries of the Mediterranean region is incomplete, as reports have been sporadic and difficult to compare. Over a 36-month period, from 2003 to 2005, the ARMed project collected 1298 susceptibility test results of invasive isolates of S. pneumoniae from blood and spinal fluid cultures routinely processed within 59 participating laboratories situated in Algeria, Cyprus, Egypt, Jordan, Lebanon, Malta, Morocco, Tunisia and Turkey. Overall, 26% (335) of isolates were reported as non-susceptible to penicillin, with the highest proportions being reported from Algeria (44%) and Lebanon (40%). During the same time period, the highest proportions of pneumococci that were not susceptible to erythromycin were reported from Malta (46%) and Tunisia (39%). Proportions of dual non-susceptibility in excess of 5% were found in laboratories in Algeria, Tunisia, Lebanon, Jordan and Turkey. ARMed data on the antimicrobial resistance epidemiology of S. pneumoniae in the southern and eastern Mediterranean region provided evidence of high rates of resistance, especially to penicillin. This evidence calls for a greater focus on the identification of relevant drivers of resistance and on the implemention of effective practices in order to address the problem of resistence.     

肺炎链球菌青霉素耐药相关基因研究

目的　了解我国肺炎链球菌 (Streptococcuspneumoniae,Sp)青霉素耐药相关基因的存在与突变状况。方法　设计、优化pbp1a、TEM基因PCR检测体系及扩增产物全自动DNA序列测定体系 ,对 3株分离自苏州地区患儿呼吸道的Sp(青霉素低耐株SR0 17、SR0 19;青霉素敏感株SR0 2 8,3株均苯唑青耐药 ,且SHV基因均为阴性 )进行检测 ,测得的pbp1aDNA序列与SpR6株 (青霉素敏感株 )DNA序列相比较 ;测得的TEM基因DNA序列与同院原分离的产超广谱 β内酰胺酶大肠埃希菌中检出的TEM 1DNA序列及已在GenBank登录的TEM基因序列相比较。结果　SR0 17、SR0 19、SR0 2 8之pbp1a基因均有突变 ,突变率为 2 1%、2 1%、0 .4 %。SR0 19株TEM基因阴性 ,SR0 17和SR0 2 8TEM基因阳性 ,测得DNA序列分别被证实为TEM 12 9和TEM 1,前者且是新型TEM ,作为新发现的菌种耐药基因均已登录美国国立生物信息中心GenBank ,登录号AY4 5 2 6 6 2、AY392 5 31;二者DNA序列与产超广谱 β内酰胺酶大肠埃希菌中检出的TEM高度同源 (99.7%、99.8% )。结论　我国Sp青霉素耐药可能存在产 β内酰胺酶 (获得TEM基因 )和pbp基因突变两种机制 ,TEM耐药质粒可能在不同种菌株间传播。     

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.