中国西部单中心二级医院呼吸道感染住院患儿鼻咽部肺炎链球菌携带及其血清型和耐药性的横断面调查

目的 了解不发达地区二级医院呼吸道感染住院患儿鼻咽部肺炎链球菌的携带情况及分离株的血清型分布和耐药性特征。方法 采集重庆市酉阳土家族苗族自治县人民医院（简称酉阳医院）2015年1~12月呼吸道感染住院患儿鼻咽拭子标本,培养并分离肺炎链球菌,采用荚膜肿胀实验对分离株进行血清分型。随机选取50%的肺炎链球菌分离株以E-test法和纸片扩散法对16种常见抗菌药物检测其敏感性。结果 研究期间共采集鼻咽拭子标本1 054份,分离出肺炎链球菌267株,分离率为25.3%。≤5岁儿童分离率较高,冬春季分离率较高。267株肺炎链球菌分离株中最常见的血清型为19F型（47株,17.6%）,其次为6A（35株,13.1%）、14（31株,11.6%）、19A（28株,10.5%）、23F（28株,10.5%）和6B型（25株,9.4%）。13价肺炎链球菌结合疫苗（PCV13）的覆盖率为73.8%（197/267）。136株肺炎链球菌行抗生素药敏试验,所有菌株对头孢曲松、万古霉素和左氧氟沙星敏感,对利奈唑胺、亚胺培南和泰利霉素的敏感率较高,分别为96.3%、87.5%和84.5%;静脉青霉素的敏感率为100%,口服青霉素的敏感率为16.9%。99.3%（135/136)的分离株对红霉素和阿奇霉素耐药。PCV13覆盖株对口服青霉素、头孢吡肟、头孢呋辛和亚胺培南的不敏感率明显高于非PCV13覆盖株（P<0.01）。19A型菌株对口服青霉素、头孢吡肟不敏感率为100%。结论 酉阳医院呼吸道感染住院患儿鼻咽部肺炎链球菌的分离率为25.3%,常见血清型为19F、6A、14、19A、23F和6B,PCV 13覆盖率较高,且PCV13覆盖株对口服青霉素、头孢吡肟、头孢呋辛和亚胺培南的不敏感率明显高于非PCV13覆盖株。     

上呼吸道感染儿童鼻咽部携带肺炎链球菌状况及血清型和耐药性研究

目的 了解上呼吸道感染儿童鼻咽部携带肺炎链球菌状况,以及分离株的耐药性和血清型分布。方法 2013 年3 月至2014 年2 月采集在北京儿童医院门诊就诊的上呼吸道感染儿童鼻咽拭子进行细菌培养和鉴定,采用Etest 方法检测抗生素敏感性,荚膜肿胀试验检测血清型。结果 共采集到2 941 例1 月龄至16 岁患儿的鼻咽拭子,分离出肺炎链球菌699 株,携带率为23.8%。随机选取100 株菌检测了抗生素敏感性和血清型。分离株对静脉青霉素敏感率达98.0%,口服青霉素敏感率仅为33.0%,头孢克洛耐药率为54.0%,头孢曲松和亚胺培南中介率也分别达到18.0% 和38.0%。红霉素和阿奇霉素不敏感率均为97.0%。多重耐药率为86.0%。常见血清型为6A（12.0%）、19F（12.0%）、6B（10.0%）、23F（9.0%）和14 型（8.0%）,7、10 和13 价结合疫苗覆盖率分别为41.0%、42.0% 和59.0%。结论 门诊上呼吸道感染儿童中,鼻咽部肺炎链球菌携带率约为25%,抗生素耐药分离株常见,13 价结合疫苗覆盖率接近60.0%。     

住院肺炎患儿不同血清型肺炎链球菌对抗菌药物的耐药性分析

目的 了解当前从我国住院肺炎儿童分离的肺炎链球菌血清型分布和不同血清型菌株对抗菌药物的耐药状况,评估应用疫苗预防儿童肺炎链球菌感染和控制耐药菌传播的价值。方法 肺炎链球菌分离自4家儿童医院呼吸科年龄 ≤ 5岁的住院肺炎患儿,采用荚膜肿胀试验进行血清型分析,E试验法检测菌株对8种抗菌药物的敏感性。结果 279株肺炎链球菌中以19F型为最常见（占60.6%）,其次为19A（9.7%）。23F（9.3%）和6B（5.4%）,7价结合疫苗（PCV7）覆盖率为81.0%,PCV7在青霉素不敏感菌株和敏感菌株中的覆盖率分别为84.2%（202/240）和61.5%（24/39）。超过90%的19F和19A型菌株对青霉素不敏感,19F型以中介株为主（71.6%）,19A型以耐药株为主（55.6%）。结论 住院儿童肺炎病例分离的肺炎链球菌以19F。19A。23F和6B型常见;PCV7覆盖大多数肺炎链球菌和青霉素不敏感菌株,应用该疫苗可有效地预防国内儿童肺炎链球菌感染和阻止耐药菌株传播;非PCV7覆盖的19A型具有较强耐药性。     

四家儿童医院住院肺炎病例肺炎链球菌分离株的耐药性监测

目的：了解从我国住院肺炎儿童分离的肺炎链球菌对抗菌药物的敏感性状况,为临床用药提供依据。方法：肺炎链球菌分离自2006年2月~2007年2月在北京、上海、广州和深圳4家儿童医院住院的肺炎患儿,采用E试验法检测菌株对8种抗生素的敏感性。结果：279株肺炎链球菌对青霉素的不敏感率为86.0％,耐药率达23.3％。在检测的β内酰胺类抗菌药物中,肺炎链球菌对阿莫西林还保持着很高的敏感率（92.1％）,对头孢呋辛和头孢曲松的敏感率分别为19.0％和75.3％。几乎全部菌株（99.6％）对红霉素耐药。万古霉素和氧氟沙星的敏感率分别为99.6％和97.8％。17.6％的分离株对亚胺培南不敏感,以中介株为主。不同地区分离的肺炎链球菌对红霉素、万古霉素和氧氟沙星的敏感状况没有明显不同,但对其他几种抗菌药物的敏感性状况存在差异。结论：从肺炎住院儿童分离的肺炎链球菌对阿莫西林、万古霉素和氧氟沙星敏感率高,对头孢曲松和亚胺培南比较敏感,对青霉素、头孢呋辛和红霉素普遍不敏感或耐药。     

北京上海广州深圳4家儿童医院肺炎住院患儿肺炎链球菌分离株的血清型分布

目的了解目前从中国住院治疗肺炎患儿分离到的肺炎链球菌的血清型分布，及几种蛋白多糖结合疫苗的覆盖率，评估应用蛋白多糖结合疫苗预防肺炎链球菌感染的价值。方法选择2006年2月16日至2007年2月16日在首都医科大学附属北京儿童医院、复旦大学附属儿科医院、广州市儿童医院和深圳市儿童医院呼吸科住院治疗的肺炎患儿为研究对象，采用一次性吸痰管收集全部病例的呼吸道分泌物标本分离肺炎链球菌，部分患儿进行脑脊液、血液和胸腔积液中肺炎链球菌的分离。采用荚膜肿胀实验进行血清型分析。对4家儿童医院肺炎链球菌分离率和血清型进行分析，率的比较采用χ2检验或Fisher精确概率法。结果 研究期间共纳入2 865例肺炎患儿，2 865例呼吸道吸取物标本中分离到肺炎链球菌279株，其中有2株不同血清型菌株分离自同一病例，分离阳性率为9.7％（278/2 865）。3/8例胸腔积液中分离到肺炎链球菌，其中2例同时从呼吸道分泌物分离到肺炎链球菌，取其一进行血清分型，另1株从胸腔积液中分离的肺炎链球菌复苏失败，未进行血清分型。脑脊液和血液标本中未分离到肺炎链球菌。共有279株肺炎链球菌进行了血清型分析，以19F型最常见（60.6％，169/279），其次为19A（9.7％，27/279）、23F（9.3％，26/279）和6B（5.4％，15/279），上述4种血清型占全部菌株的84.9％（237/279）。肺炎链球菌7价结合疫苗（PCV7）覆盖率为81.0％，但在北京仅为46.0％，明显低于上海（80.0%）、广州(98.4%)和深圳（94.4%）。9价、10价和11价疫苗的覆盖率与PCV7相比并没有明显增加。13价疫苗的覆盖率（92.8％）较PCV7明显升高。结论4家儿童医院肺炎住院患儿分离的肺炎链球菌以19F、19A、23F和6B型常见。PCV7覆盖率为87％     

中国2岁以下健康婴幼儿鼻咽部携带常见病原菌的血清分型及耐药性分析

目的分析2岁以下健康婴幼儿鼻咽部携带肺炎链球菌的血清型特点,监测肺炎链球菌、流感嗜血杆菌、卡他莫拉菌对常规用药的体外敏感性。方法采用荚膜肿胀试验对肺炎链球菌进行血清分型,E-test法测定肺炎链球菌(451株)、流感嗜血杆菌(168株)、卡他莫拉菌(396株)的体外敏感性,头孢硝噻吩试验检测流感嗜血杆菌、卡他莫拉菌β内酰胺酶的产生情况。结果肺炎链球菌、流感嗜血杆菌和卡他莫拉菌的携带率分别为12.4%、4.6%、10.9%;肺炎链球菌血清分型中19F最多见,其余依次为14、19A和15、6B、23F、6A,且春季和秋冬季无明显差别;PCV7、PCV9、PCV10价疫苗覆盖率均为48.6%,PCV13覆盖率为61.0%,后者明显高于前者;此外,19A的耐药性高于多数血清型(包括19F),23F的耐药性强于其他血清型,6A的耐药性强于6B。不同城市间青霉素耐药肺炎链球菌、青霉素中介肺炎链球菌、青霉素敏感肺炎链球菌所占比例分别为11.6%～28.6%、19.6%～54.4%、32.0%～62.8%。流感嗜血杆菌和卡他莫拉菌对大部分抗菌药物敏感,22.7%和21.0%的卡他莫拉菌对红霉素和阿奇霉素耐药,济南的耐药率高达50.0%和44.8%。卡他莫拉菌β-内酰胺酶阳性率为85.0%～100.0%;未发现β-内酰胺酶阴性氨苄西林耐药的流感嗜血杆菌。结论 2岁以下健康婴幼儿鼻咽部携带肺炎链球菌中以19F最多见,19A耐药性强于其他血清型;肺炎链球菌、流感嗜血杆菌及卡他莫拉菌对常用抗生素的耐药性增加,应引起高度重视。     

儿童呼吸道感染常见革兰阳性致病菌耐药性研究

目的 研究儿科患者呼吸道感染常见致病菌(肺炎链球菌、金黄色葡萄球菌及A族乙型溶血性链球菌)的耐药情况.方法 对2004年1月至2006年12月首都医科大学附属北京友谊医院儿科呼吸道感染患儿鼻咽分泌物分离的55株金黄色葡萄球菌、49株肺炎链球菌、15株A族乙型溶血性链球菌采用K-B纸片法进行抗生素敏感性检测.结果 49株肺炎链球菌对红霉索的耐药率高达90%,青霉素不敏感株5株,占10%,多重耐药率高达90%;55株金黄色葡萄球菌对氨苄西林耐药率为86%,对青霉素耐药率为82%,对苯唑西林耐药率为9%,且多重耐药问题很严重;15株A族乙型溶血性链球菌对红霉素的耐药率为80%,对青霉素和氨苄西林敏感.结论 儿童呼吸道感染常见致病菌的耐药情况不容乐观.肺炎链球菌及A族乙型溶血性链球菌对红霉素的耐药性很高;发现了耐甲氧西林的金黄色葡萄球菌,且多重耐药问题很严重.儿童呼吸道细菌感染时,应尽量避免使用非β-内酰胺类抗生素.     

2003-2004年广州地区儿童肺炎链球菌、流感嗜血杆菌抗生素敏感性调查

目的了解2003-2004年广州地区儿童呼吸道感染常见病原肺炎链球菌和流感嗜血杆菌对常用抗生素的敏感性,以便有效指导临床合理用药和预防.方法对2003-2004年在广州市儿童医院就诊的1565例上呼吸道感染儿童鼻咽分泌物进行培养,分离肺炎链球菌和流感嗜血杆菌;采用纸片扩散法及E-test方法对分离株进行常用抗生素敏感性检测.结果从1565例呼吸道感染儿童鼻咽部分离肺炎链菌球共172株,流感嗜血杆菌484株.172株肺炎链球菌对常用抗生素耐药株数（耐药率）分别为：青霉素55（32.0%）、阿莫西林/克拉维酸19（11.1%）、头孢曲松56（32.6%）、头孢呋辛31（18.1%）、头孢克洛68（39.5%）、红霉素142（82.6%）、四环素135（78.5%）、氯霉素42（24.4%）、复方磺胺甲基异噁唑150（87.2%）、克林霉素119（69.2%）、氧氟沙星5（3.1%）;肺炎链球菌的青霉素不敏感株对β-内酰胺类、红霉素、复方磺胺甲基异噁唑耐药率明显高于青霉素敏感株,且多重耐药率在90%以上.484株流感嗜血杆菌中,143株β-内酰胺酶阳性,产酶率为29.5%,484株流感嗜血杆菌的耐药株数（耐药率）分别为：氨苄西林194（40.1%）,阿莫西林/克拉维酸16（3.4%）、头孢曲松20（4.1%）、头孢呋辛9（1.9%）、头孢克洛27（5.6%）、复方磺胺甲基异噁唑272（56.2%）、四环素252（52.1%）、氯霉素84（17.4%）、阿奇霉素10（2.1%）、氧氟沙星3（0.6%）.结论广州地区儿童呼吸道肺炎链球菌和流感嗜血杆菌耐药形势严峻,与该地区前3年资料比较,肺炎链球菌对青霉素敏感性有所增加,但对头孢曲松耐药性增加,青霉素不敏感株的多重耐药率较高,以红霉素、四环素、复方磺胺甲基异噁唑多重耐药为主要特点.流感嗜血杆菌的产酶率上升,导致菌株对氨苄西林耐药性明显增高,对头孢二、三代抗生素、阿莫西林/克拉维酸、阿奇霉素有较高的敏感性.     

住院肺炎患儿不同血清型肺炎链球茵对抗菌药物的耐药性分析

目的 了解当前从我国住院肺炎儿童分离的肺炎链球萧血清型分布和不同血清型菌株对抗菌药物的耐药状况,评估应用疫苗预防儿童肺炎链球菌感染和控制耐药菌传播的价值.方法 肺炎链球菌分离自4家儿童医院呼吸科年龄≤5岁的住院肺炎患儿,采用荚膜肿胀试验进行血清型分析,E试验法检测菌株对8种抗菌药物的敏感性.结果 279株肺炎链球菌中以19F型为最常见(占60.6%),其次为19A(9.7%)、23F(9.3%)和6B(5.4%),7价结合疫苗(PCV7)覆盖率为81.0%,PCV7在青霉素不敏感菌株和敏感菌株中的覆盖率分别为84.2%(202/240)和61.5%(24/39).超过90%的19F和19A型菌株对青霉素不敏感,19F型以中介株为主(71.6%),19A型以耐药株为主(55.6%).结论 住院儿童肺炎病例分离的肺炎链球菌以19F、19A、23F和6B型常见;PCV7覆盖大多数肺炎链球菌和青霉素不敏感菌株,应用该疫苗可有效地预防国内儿童肺炎链球菌感染和阻止耐药菌株传播;非PCV7覆盖的19A型具有较强耐药性.     

5岁以下健康儿童鼻咽部肺炎链球菌的流行病学研究

目的了解武汉地区儿童肺炎链球菌携带率、耐药性、耐药基因及血清型流行状况。方法采集鼻咽拭子,以琼脂稀释法测定肺炎链球菌对12种抗菌药物的最低抑菌浓度,聚合酶链式反应检测红霉素耐药基因,荚膜肿胀试验进行血清学分型。结果武汉地区儿童肺炎链球菌携带率为22．31％（135／605）。存活的133株细菌中,青霉素不敏感肺炎链球菌（PNSSP）发生率为45．9％（61／133）;头孢菌素第一代（头孢氨苄）、二代（头孢克洛）、三代（头孢克肟、头孢泊肟、头孢曲松）敏感率依次为6．0％、45．1％、54．9％、56．4％、88．7％;除1株环丙沙星低耐株外,未发现氟喹诺酮类耐药株。大环内酯类敏感率仅为14．3％～15．8％。在114株红霉素耐药株中,检出ermB基因76株（66．7％）,2株（1．8％）低耐株含有mefA基因,46株（40．4％）同时具有ermB和mefA基因。血清分型涉及17个血清群,主要分布在19、23、6、15和14血清群,7株细菌未能分群。PNSSP分布在19、23、6和未分型血清群。结论武汉地区肺炎链球菌耐药严重,红霉素耐药主要为核糖体修饰（ermB介导）引起。流行血清群以19、23、6为主。     

Seven valent pneumococcal conjugate vaccine immunization in two Boston communities: changes in serotypes and antimicrobial susceptibility among Streptococcus pneumoniae isolates

BACKGROUND: Seven valent pneumococcal conjugate vaccine (PCV7) was licensed and introduced in 2000 for universal administration of children younger than 2 years of age and for selective immunization of children 2-5 years of age. SPECIFIC AIMS: To identify changes in colonization and antimicrobial susceptibility among Streptococcus pneumoniae organisms after introduction of PCV7. METHODS: Infants and children ages 2-24 months were enrolled in surveillance study of nasopharyngeal carriage of S. pneumoniae. Nasopharyngeal cultures for S. pneumoniae were performed at all well child visits and illness visits of children with acute otitis media. S. pneumoniae organisms were serotyped, and antimicrobial susceptibilities to penicillin, amoxicillin, trimethoprim-sulfamethoxazole and azithromycin were performed. RESULTS: During the 3-year period (October 2000 through September 2003), nasopharyngeal colonization with vaccine serotypes declined from 22% to 2%, and nonvaccine serotypes increased from 7% to 16%. Rates of antibiotic resistance of S. pneumoniae isolates to penicillin, amoxicillin, azithromycin and trimethoprim-sulfamethoxazole were 29.3, 2.2, 26.5 and 28.1%, respectively. CONCLUSIONS: PCV7 immunization produces a marked decline in vaccine serotypes carried in the nasopharynx of young children, with a coincident rise in the prevalence of nonvaccine serotypes. Important shifts in antimicrobial susceptibility have not been observed to date.     

Increased antimicrobial resistance among nonvaccine serotypes of Streptococcus pneumoniae in the pediatric population after the introduction of 7-valent pneumococcal vaccine in the United States

BACKGROUND: The 7-valent pneumococcal conjugate vaccine (PCV7) was introduced in the United States in February 2000. The PROTEKT US study evaluated serotype distribution, PCV7 coverage and antimicrobial susceptibility among Streptococcus pneumoniae isolates collected from children aged 0 to 14 years in 2000 through 2001 (year 1; n = 2033), 2002 through 2003 (year 3; n = 1740) and 2003 through 2004 (year 4; n = 1591). METHODS: Serotyping was performed by Neufeld Quellung reaction. Antimicrobial susceptibilities were determined centrally according to Clinical Laboratory Standards Institute methodology and interpretive breakpoints. RESULTS: The proportion of isolates covered by PCV7 (vaccine serotypes) decreased from 65.5% (year 1) to 34.7% (year 3) and to 27.0% (year 4) (P < 0.0001) with similar changes seen at regional and state levels. The most common serotypes in year 4 were nonvaccine serotypes (NVS) 19A (19.0% of all isolates), 6A (7.8%), 3 (7.6%), 15 (6.3%) and 35B (5.8%) and vaccine serotype 19F (12.7%). NVS 19A increased relative to vaccine serotype 19F among isolates expressing the erm(B) + mef(A) macrolide-resistant genotype (P < 0.0001) between year 1 (7.8% [19A] versus 86.7% [19F]) and year 4 (45.5% [19A] versus 51.7% [19F]). Antimicrobial resistance rates (year 1 versus year 4) among NVS from nonblood (respiratory tract) sources increased for penicillin (resistant: 12.7-16.1% [P = 0.0857]; intermediate susceptibility: 20.1-31.5% [P < 0.0001]), erythromycin (21.2-31.6% [P < 0.0001]), amoxicillin-clavulanate (1.4-5.8% [P < 0.0001]) and multidrug resistance (resistance to > or =2 antimicrobial classes) (24.6-31.6% [P = 0.0034]). CONCLUSIONS: The proportion of S. pneumoniae isolates from U.S. pediatric patients covered by PCV7 decreased substantially in the 4 years after vaccine introduction. However, resistance to commonly used antimicrobials, including beta-lactams and macrolides, as well as multidrug-resistant strains increased significantly among respiratory tract isolates of NVS.     

Epidemiology of Streptococcus pneumoniae in Italian children

In Italy, data regarding the aetiological role, antibiotic resistance, and serotype distribution of isolates of Streptococcus pneumoniae are scarce and based on very small population samples. We found that S. pneumoniae caused about 30% of lower respiratory tract infections and 15% of acute otitis media infections in Italian children. The incidence of S. pneumoniae meningitis in subjects aged 0-4y was 1.1 x 100,000. In children <5 y of age with meningitis, the most common S. pneumoniae serotypes were, in rank order, 14, 6, 23, 1 and 4; among 53 nasopharyngeal carriers the most frequent serotypes were 6 and 19. The actual percentage of resistance of S. pneumoniae to penicillin is 10.2%, while for macrolides it reaches 25.5%. More data on the distribution of serotypes in Italian children are urgently needed in order to obtain a better understanding of the impact of the new pneumococcal vaccines.     

Epidemiology of Streptococcus pneumoniae in Italian children

In Italy, data regarding the aetiological role, antibiotic resistance, and serotype distribution of isolates of Streptococcus pneumoniae are scarce and based on very small population samples. We found that S. pneumoniae caused about 30% of lower respiratory tract infections and 15% of acute otitis media infections in Italian children. The incidence of S. pneumoniae meningitis in subjects aged 0–4y was 1.1 ± 100000. In children <5y of age with meningitis, the most common S. pneumoniae serotypes were, in rank order, 14, 6, 23, 1 and 4; among 53 nasopharyngeal carriers the most frequent serotypes were 6 and 19. The actual percentage of resistance of S. pneumoniae to penicillin is 10.2%, while for macrolides it reaches 25.5%. More data on the distribution of serotypes in Italian children are urgently needed in order to obtain a better understanding of the impact of the new pneumococcal vaccines.     

儿童呼吸道感染肺炎链球菌耐药性及pbp2B与TEM基因的研究

目的：了解广州地区儿童呼吸道感染肺炎链球菌(Streptococcus pneumoniae,SP)的耐药情况以及SP中青霉素耐药相关基因TEM与pbp2B的流行分布及突变情况。方法：采用E-test和K-B纸片法对44株SP分离株进行药敏试验;PCR扩增SP中的TEM基因及pbp2B,并对pbp2B基因进行测序,结果与SP青霉素敏感株R6进行序列比对分析。结果：①44株SP对青霉素的敏感率仅为11.4％,不敏感率高达88.6％。对红霉素耐药率已达100％,对克林霉素、复方新诺明的耐药性也在90％以上。但对头孢曲松、阿莫西林、亚胺培南仍敏感,耐药率分别为0,2.6%和3.9%。未发现对氧氟沙星、万古霉素耐药菌株。②44株SP的pbp2B基因扩增序列与R6敏感株相比较,5株青霉素敏感株99%以上的核苷酸序列相同,未发生氨基酸的替换。39株青霉素不敏感株均发生核苷酸序列的改变,核苷酸序列突变率为13.2％～23.1%,约6.5％～10.9%的氨基酸发生了替换。根据氨基酸在Ser391-Thr492片段之间的突变情况,可将39株青霉素不敏感株分为四型,其中Ⅰ型突变30株,Ⅱ型突变7株,Ⅲ型和Ⅳ型各1株。44株SP均未检出TEM型β-内酰胺酶耐药基因。结论：广州地区儿童呼吸道感染SP多重耐药情况较严重,青霉素、红霉素已不适宜作为SP感染的临床一线用药,阿莫西林及第三代头孢菌素可作为SP感染的经验用药。pbp2B基因突变是广州地区儿童SP对青霉素耐药的主要机制之一。［中国当代儿科杂志,2009,11（8）：623-626］     

Nasopharyngeal carriage of Streptococcus pneumoniae in healthy Turkish children after the addition of PCV7 to the national vaccine schedule

The aim of this study was to determine serotype distribution and investigate antimicrobial resistance patterns of Streptococcus pneumoniae in healthy Turkish children in the era of community-wide pneumococcal conjugate vaccine (PCV7). The study was conducted on 1,101 healthy children less than 18 years of age. Specimens were collected with nasopharyngeal swabs between April 2011 and June 2011. Penicillin and ceftriaxone susceptibilities were determined by E-test according to the 2008 Clinical Laboratory Standards Institute, and serotypes of the isolates were determined by Quellung reaction. The nasopharyngeal pneumococcal carriage rate was 21.9 % (241/1,101). Using the meningitis criteria of minimum inhibitory concentration values, 73 % of the isolates were resistant to penicillin and 47.7 % of them were resistant to ceftriaxone. Half of all pneumococcal isolates were serotyped as 19F (15.2 %), 6A (15.2 %), 23F (10.3 %), and 6B (9.3 %) and surprisingly, no serotype 19A was isolated. Serotype coverage rates of PCV7 and non-PCV7 were 46.2 and 53.8 %, respectively. The most common penicillin- and ceftriaxone-resistant serotypes were 6A, 6B, 14, 19F, and 23F. Penicillin- and ceftriaxone-resistant isolates were more prevalent in serotypes covered by PCV7 than the non-PCV7 serotypes. Conclusion: After the community-wide PCV7 vaccination, more non-PCV7 serotypes were isolated from the carriers compared to the time before PCV7 was used especially the serotype 6A, and the antimicrobial resistance of pneumococci was significantly increased.     

Nasopharyngeal carriage of penicillin-resistant Streptococcus pneumoniae in healthy children

Streptococcus pneumoniae carriage is a risk factor for the development of respiratory system infections and the spread of penicillin-resistant strains. The aim of this study was to investigate nasopharyngeal carriage of S. pneumoniae in healthy children and resistance to penicillin and other antimicrobials and to assess related risk factors. Nasopharyngeal specimens collected from healthy children less than six years of age, visiting a Mother and Child Health Center for health control, were investigated microbiologically between February-March 2004. Carriage rate was 37.2% (n=112/301); 33.9% intermediate and 5.4% high penicillin resistance were detected. According to multivariate analysis, carriage rate was inversely related to number of rooms (OR:0.574) and child age (OR:0.978), while penicillin resistance was correlated well with antibiotic use in the last two months (OR:2.193). Decreased sensitivity plus resistance to other antimicrobials were: trimethoprim-sulfamethoxazole (TMP-SMX) 45.6%; erythromycin 16.1%, tetracycline 16.1%; clindamycin 9.8%, and ofloxacin 3.6% in pneumococcal isolates, which increased significantly (p<0.05) to 72.7%, 31.8%, 27.3%, 20.5%, and 6.8%, respectively, in penicillin non-sensitive S. pneumoniae (PNSSP) except for ofloxacin. Overall multidrug resistance was 17.9%, while PNSSP exhibited a resistance rate of 38.6%. In conclusion, S. pneumoniae carriage rates determined in healthy children were high and PNSSP strains also showed increased resistance to other antimicrobials.     

Serotype distribution and antimicrobial resistance patterns in Streptococcus pneumoniae isolates from hospitalized pediatric patients with respiratory infections in Shanghai,China

BACKGROUND: Surveillance for pneumococcal respiratory illness was conducted in children hospitalized at Affiliated Pediatric Hospital of Fudan University in Shanghai from August 2000 to August 2001. METHODS: Sputum cultures were obtained from pediatric patients admitted with pneumonia or respiratory distress by tracheal aspirate. Blood cultures were also performed on a subset of patients. All pneumococcal isolates were serotyped and tested for antibiotic susceptibility. In addition clinical information on the patients including prior antibiotic history was abstracted. Streptococcus pneumoniae tracheal isolations were attempted in a total of 1013 pediatric patients hospitalized during this period. Among these samples 112 specimens were S. pneumoniae-positive. These positive isolates underwent serotyping and antibiotic susceptibility testing. RESULTS: Five serotypes (19F, 23F, 6A, 14, 6B) of S. pneumonia accounted for 81% (91 of 112 cases). Other serotypes accounted only for 12% (13 of 112 cases), and 7% (8 of 112 cases) of isolates could not be typed by quelling test. Only one blood culture isolate was positive, probably reflecting the frequent use of antibiotic treatment before hospitalization. Fifty-one and 8.0% of isolates had intermediate and high level penicillin resistance, respectively. Fifty-eight percent were resistant to ampicillin, 6.6% to cefazolin, 25.0% to cefaclor, 6.6% to ceftriaxone, 85.7% to erythromycin, 66.7% to clindamycin and 28.2% to chloramphenicol. Among 66 isolates that were not susceptible to penicillin, serotype 19F was the most common, followed by 23F and 14. CONCLUSION: S. pneumoniae is a common cause of respiratory illness requiring hospitalization in young children in Shanghai, with antibiotic resistance increasingly common. Five serotypes account for most disease.