北京地区青霉素不敏感肺炎链球菌分子流行病学的初步探讨

目的了解北京地区儿童中青霉素不敏感肺炎链球菌（PNSP）的流行状况,阐明其分子流行病学特征。方法以2000-2002年于0～5岁上呼吸道感染儿童鼻咽部分离的63株PNSP冻存标本为研究对象,进行耐药模式分析,以聚合酶链反应（PCR）扩增青霉素结合蛋白（PBP）基因pbpla、pbp2b和pbp2x,分析其限制性片段长度多态性（RFLP）,并进行细菌染色体RFLP脉冲场凝胶电泳（PFGE）比较。结果63株PNSP有61株（96．8％）为多重耐药菌株。pbpla、pbp2b和pbp2x分别有8、9和18种基因型,三者组合的谱型共有30种。63株PNSP的PFGE型共分为35个,其中,9种PFGE型包括菌株≥2株,这9种型共包含37株,占59％,均为多重耐药菌株。与亚洲流行菌株比较,我们发现2株PFGE型可能相关的PNSP分别与亚洲流行菌株越南-19群、新加坡-19群、中国台湾-19群和韩国-19群谱型完全相同。结论北京地区儿童中PNSP的多重耐药状况严峻,克隆传播是PNSP流行的重要因素;已存在与亚洲流行菌株相同的克隆,值得关注。     

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。     

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.     

基因检测pbp2b ply和lytA诊断儿童肺炎链球菌脑膜炎应用价值研究

目的比较青霉素结合蛋白2b(pbp2b)与自溶素(ply)、溶血素(lyt A)基因和脑脊液细菌培养在诊断国内儿童化脓性脑膜炎中肺炎链球菌感染及青霉素耐药性方面的情况,并了解肺炎链球菌青霉素结合蛋白基因型特征。方法 2006年1月至2009年9月在北京儿童医院感染内科临床严格诊断为细菌性脑膜炎患儿161例,用pbp2b及其他2个肺炎链球菌种特异的基因(ply、lyt A)巢式PCR法来检测细菌性脑膜炎患儿脑脊液中的肺炎链球菌,对不同方法结果进行比较。对其中pbp2b阳性的标本进行青霉素敏感性PCR(分别用耐药、敏感的引物进行PCR检测)、测序,并与青霉素耐药表型进行比较和评估。结果 161例中不同方法确诊的肺炎链球菌共有25例,3种基因检测均阳性的共有11例。pbp2b检测阳性16例,lyt A检测阳性16例,ply检测阳性14例。脑脊液培养阳性9例。pbp2b阳性的16例标本中,青霉素敏感和青霉素耐药基因型各占一半。16例中4例有培养结果,其中3例基因型和耐药型相符合。敏感性测定PCR和测序结果相一致。测序结果与NCBI基因库(http://blast.ncbi.nlm.nih.gov/Blast.cgi)相比,有2例为新的氨基酸序列型,但是无新的氨基酸点突变发生。由培养结果检测的肺炎链球菌脑膜炎的青霉素耐药率为66.67%(6/9),敏感性PCR检测的肺炎链球菌脑膜炎的青霉素耐药率为50%(8/16),包括脑脊液培养阴性的病例。结论 3种基因检测的敏感度均高于传统的脑脊液培养,其中pbp2b可以作为一个推荐的基因位点筛查肺炎链球菌感染,并在一定程度上预测青霉素耐药性情况。     

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。     

北京地区上呼吸道感染儿童青霉素不敏感肺炎链球菌的血清型分布研究

目的 了解青霉素不敏感肺炎链球菌（PNSP）的耐药性和血清型分布。方法 以2000～2004年门诊上呼吸道感染的0～5岁患儿鼻咽部分离的肺炎链球菌为研究菌株,采用E-test法检测青霉素最低抑菌浓度,简易棋盘式分型系统进行血清分型。结果 检出PNSP菌株129株,其中中介102株,耐药27株;2000～2004年各年耐药株占PNSP比率分别为19．0％、8．0％、17．6％、30．0％和26．1％;常见血清型共有124株（96．1％）,为19群、23群、不能分型、6群和14型;7价结合疫苗覆盖率从2000年到2004年分别为57．1％、76．0％、88．2％、75．0％和82．6％。结论 北京儿童中分离的PNSP的青霉素耐药性有所增强;7价结合疫苗覆盖率升高,有利于应用疫苗来预防PNSP的携带、感染及耐药性的进一步播散。     

肺炎链球菌100株耐药性分析

目的　了解杭州地区小儿肺炎链球菌致病株的耐药特征。方法　用Kirby -Bauer法对浙江大学儿童医院 2 0 0 1年 7月至 2 0 0 2年 1月鉴定的 10 0株肺炎链球菌进行耐药性分析 ,同时用E -test法测定青霉素、氨苄西林、头孢噻肟和红霉素的最低抑菌浓度。结果　青霉素不敏感株 6 1株占 6 1% ,其中中介株占 46 % ,耐药株占15 % ,其最低抑菌浓度范围为 0 0 16～ 3 0 0 0mg/L ,平均 0 5 2 3mg/L。 92 %的菌株对红霉素耐药 ,对四环素、复方新诺明的耐药率也分别高达 85 %和 5 6 % ,氯霉素的耐药率为 16 %。多重耐药率为 6 3 % ,其中多数对红霉素、四环素和复方新诺明联合耐药。 99%的菌株对利福平敏感。未发现氨苄西林耐药株 ,但中介株达 43 %。所有的菌株都对头孢噻肟、万古霉素和氧氟沙星敏感。结论　杭州地区肺炎链球菌耐药现象比较严重 ,第三代头孢菌素是临床治疗耐青霉素肺炎链球菌感染的理想药物。     

杭州地区肺炎链球菌耐药性及遗传背景研究

目的 了解杭州地区肺炎链球菌儿童株的耐药性和流行特征。方法 用Kirby-Bauer法和Etest法对323株肺炎链球菌致病株和携带株进行耐药性分析,并对青霉素耐药株及部分相关菌株用BOX-PCR技术进行遗传背景研究。结果 青霉素敏感株136株,占42．1％,青霉素中介株和耐药株分别占40．2％和17．7％。青霉素的最低抑菌浓度范围为0．012～4．0μg／ml。所有菌株都对头孢噻肟和万古霉素敏感。90．7％的菌株对红霉素耐药,对四环素、甲氨苄啶一磺胺异嗯唑的耐药率也分别高达87．6％和48．6％,对氯霉素的耐药率为14．9％。多重耐药率61．0％,多数对红霉素、四环素和甲氨苄啶一磺胺异嗯唑联合耐药。99．4％的菌株对利福平和氧氟沙星敏感。BOX-PCR分析耐青霉素肺炎链球菌的临床株,未发现高度集中分布的BOX图谱,同一标本中分离到的表型不同的菌株或同一病人多次分离到的菌株BOX图谱可以不完全相同。结论 杭州地区肺炎链球菌耐药现象比较严重,头孢噻肟等第三代头孢菌素是治疗肺炎链球菌感染的理想药物。同一病人可同时或先后受不同肺炎链球菌克隆感染或定植。     

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］     

流感嗜血杆菌脉冲电场凝胶电脉法分型研究

为了解北京儿童医院流感嗜血杆菌（Hi)抗生素耐药菌株和b型菌株（Hib)的分子流行病学情况，采用脉冲电场凝胶电泳9PFGE）方法，对1999年和2000年分离的氨苄青霉素，头孢菌素耐药株，b型流感嗜血杆菌菌株和随机选取的非b型抗生素敏感菌株进行分型。结果显示，20株Hi菌株得到19种不同PFGE带型。1999年3株氨苄青霉素耐药菌株中有2株仅有一条带的差别；4株Hib菌株中，2株带型完全相同，与另1株有一条带的差别；2株头孢菌素耐药株有各自不同带型。2000年所有菌株带型各异，提示1999年从肺炎病人鼻咽部分离的氨苄青霉素耐药及Hib菌株多为流行病学相关菌株；2000年从上呼吸道感染儿童鼻咽部分离的氨苄青霉素耐药及Hib菌株无流行病学相关性。需要进一步监测方能确定有无耐药及Hib菌株流行，PFGE是对Hi进行流行病学研究的最佳工具之一。     

Antimicrobial resistance of Streptococcus pneumoniae isolated from healthy children in day-care centers: results of a multicenter study in Russia

BACKGROUND: It has been previously shown that study of susceptibility of nasopharyngeal isolates in healthy carriers can predict resistance in clinical isolates. The purpose of this multicenter study was to determine the carriage rate of Streptococcus pneumoniae in healthy children attending day-care centers in Moscow, Smolensk and Yartsevo, Russia, and in vitro activity of penicillin G, amoxicillin/clavulanate, cefaclor, erythromycin, roxithromycin, clarithromycin and trimethoprim-sulfamethoxazole (TMP-SMX) against representative isolates. METHODS: Included in this study were 305 pneumococcal isolates from 733 children attending 9 day-care centers in Moscow, Smolensk and Yartsevo. All children enrolled in this study were <7 years of age. MICs of selected antimicrobials were determined by Etest. Serotyping of selected pneumococcal isolates was done with pool and type antisera. RESULTS: The carriage rate of S. pneumoniae in the 3 centers varied from 44.9% to 66.0% (mean, 55.9%). Susceptibility testing was performed with 305 (74.4%) of 410 isolates. Only 23 (7.5%) of 305 pneumococcal isolates were penicillin-intermediate (range, 2.8 to 12.8%) with no penicillin-resistant strains. All tested pneumococci were susceptible to amoxicillin/clavulanate. Macrolides possessed comparable activity against S. pneumoniae, at 4.6% resistant strains for both erythromycin (range, 1.1 to 17.1%) and clarithromycin (range, 1.7 to 17.1%). The highest level of resistance was observed with TMP-SMX, 53.4% (range, 43.8 to 70.9%). Of 23 strains 20 (87.0%) with intermediate resistance to penicillin were serotyped. The most prevalent serotype was 14 (5 isolates), followed by serogroups 19 (4) and 23 (4). CONCLUSIONS: Resistance to penicillin, other beta-lactams and macrolides does not seem to be a problem for Russia now. The high level of resistance to TMP-SMX considerably restricts its usage for the treatment of pneumococcal infections.     

Drug-resistant pneumococci in children with acute lower respiratory infections in Vietnam

Background: Acute lower respiratory infections (ALRI), primarily pneumonia, are the leading cause of death in children under 5 years of age. Most of these deaths occur in Africa and southeast Asia. Increasing rates of drug resistance in pneumococcal strains emphasize the necessity of prevention of pneumococcal vaccines. The aim of the present study was to determine the frequency of drug resistance and the distribution of serotype of pneumococcal strains isolated from pediatric patients with ALRI in Vietnam.
Methods: Two hundred and twenty pediatric patients with ALRI under 5 years of age were enrolled in Hanoi, Vietnam between 2001 and 2002. Bacterial pathogens with a heavy growth (10⁶ c.f.u./mL) were isolated from nasopharyngeal secretions on quantitative culture. Fifty-three pneumococcal strains isolated from the nasopharynx of pediatric patients were examined for antibiotic susceptibility including drug-resistant genes and serotyping.
Results: A total of 73.6% of pneumococcal strains were genotypic penicillin-resistant Streptococcus pnemoniae (gPRSP), possessing altered penicillin-binding protein genes pbp 1a   +   2x   +   2b ; 67.9% of these strains were gPRSP and simultaneously had the ermB gene, which is responsible for high resistance to erythromycin. The majority of gPRSP strains were serotype 19F or 23F.
Conclusion: gPRSP strains with serotype 19F or 23F are highly prevalent among pediatric patients with ALRI under 5 years of age in Hanoi, Vietnam.     

Clinical and nasopharyngeal isolates of unusual multiply resistant pneumococci

Routine surveillance of pneumococcal isolates for resistance to antibiotics has revealed the emergence of an unusual pattern of multiple antimicrobial resistance in South Africa. Thirty-nine pneumococcal isolates, including 21 from clinical specimens, showed resistance to tetracycline, erythromycin, clindamycin, trimethoprim, and a combination product of trimethoprim and sulfamethoxazole sodium (co-trimoxazole), yet susceptibility to penicillin G. Multiple resistance has to date been almost invariably associated with resistance to beta-lactam antibiotics. A survey of nasopharyngeal carriage revealed carriage of an additional 21 isolates of multiply resistant pneumococci, representing 7.9% of children investigated in Johannesburg, but these organisms were not found in children in Soweto or four rural villages. We present the minimum inhibitory concentrations of 15 antimicrobial agents against 15 of these 21 strains. These findings are discussed in relation to exposure of these populations to antibiotics and to the treatment of local and systemic pneumococcal disease. Of all 60 isolates of multiply resistant pneumococci isolated to date, those fully characterized serologically belong to serotypes 6B, 14, or 19F.     

Determination of pneumococcal serotypes/genotypes in nasopharyngeal secretions of otitis media children by multiplex PCR

The appropriate clinical applications of pneumococcal polysaccharide vaccines against recent increases in antimicrobial resistant Streptococcus pneumoniae (S. pneumoniae) urgently require accurate analytical methodologies for determining and characterizing the serotypes. The results of current immunological determinations of serotypes with anti-capsular polysaccharide-specific sera are difficult to interpret in terms of quellung changes of the pneumococci. In this study, we applied the multiplex PCR technique for the rapid identification of pneumococci and simultaneous rapid determinations of their serotypes and genotypes that directly correlated with antimicrobial susceptibilities from nasopharyngeal secretions (NPS). Serogroups 6, 19F and 23F were the predominant capsular types of S. pnuemoniae in the NPS samples. Strains of serotypes 19F and 23F frequently had mutations in pbp1a, pbp2x and pbp2b and expressed ermB and mefA; they also were mostly resistant to both penicillin G (PCG) and clarithromycin (CAM). Two NPS samples contained the strain of serotype 19F together with the strain of serotype 23F, although only the strain of serotype 19F was identified by a conventional bacterial culture. Pneumococci were identified in six NPS samples and their serotypes determined by the multiplex PCR, while a conventional bacterial culture failed to identify the pathogens. Our findings suggest that PCR-based serotyping and genotyping can provide an accurate and rapid distribution of pneumococcal serotypes and antimicrobial resistance. The relatively minor populations in the nasopharynx may be determined using molecular techniques.     

Antibiotic-resistant pneumococcal disease in South African children.

OBJECTIVE--To determine the incidence of antibiotic-resistant pneumococcal disease and to compare the presentation and outcome of penicillin-resistant infections with penicillin-susceptible infections. DESIGN--Patient series. SETTING--General community hospital. PATIENTS--Eighty-three children with penicillin-resistant pneumococcal bacteremia or meningitis and 124 children with penicillin-susceptible pneumococcal bacteremia or meningitis. SELECTION PROCEDURES--Consecutive patients admitted between 1989 and 1991. INTERVENTIONS--None. MEASUREMENTS AND RESULTS--Forty percent of community-acquired isolates and 95% of hospital-acquired isolates were resistant to penicillin. Eighty-three (82%) of 101 penicillin-resistant infections were community acquired. Resistance to chloramphenicol, tetracycline, and erythromycin occurred in 9%, 12%, and 4% of all isolates, respectively. The proportion of penicillin-resistant pneumococci with cefotaxime minimum inhibitory concentrations greater than or equal to 0.5 micrograms/mL increased from 0% in a 1986 study to 21.5% in this study. The sites of infection, underlying diseases, and mortality of patients with penicillin-resistant infections outside the central nervous system did not differ significantly from those of penicillin-susceptible infections. CONCLUSIONS--The resistance of Streptococcus pneumoniae to beta-lactam antibiotics has increased alarmingly in South Africa. Penicillin-resistant and penicillin-susceptible pneumococcal infections cause a similar spectrum of illness.     

儿童肺炎链球菌分离株青霉素、红霉素耐药性与耐药相关基因研究

目的了解苏州地区儿童肺炎链球菌(Streptococcuspneumoniae,Sp)临床分离株青霉素、红霉素耐药的状况。方法对呼吸道感染患儿痰标本中分离到的26株Sp进行青霉素、头孢呋辛、头孢曲松、头孢噻肟、红霉素E test药敏试验,和与青霉素、红霉素耐药相关的pbp2B、ermB、ermA/B、mefA基因PCR检测,测得pbp2B基因产物进行测序并与SpR6株(青霉素敏感株,登录号:NC003098)序列比较。结果(1)pbp2B基因突变15株(58%),均为点突变,突变类型有A型11株(73%)、B型2株(13%)、C型1株(7%)、D型1株(7%);(2)11株无突变菌中青霉素、头孢呋辛、头孢曲松、头孢噻肟敏感株分别为9株(82%)、10株(91%)、11株(100%)、11株(100%);15株突变菌中青霉素、头孢呋辛、头孢曲松、头孢噻肟不敏感株分别为13株(87%)、11株(73%)、1株(7%)、1株(7%);11株A型突变株对青霉素均不敏感,10株对二代头孢不敏感;(3)ermB基因阳性9株(35%)、ermA/B基因阳性16株(62%)、mefA基因阳性7株(27%)、erm或(和)mef基因阳性21株(81%);(4)erm或(和)mef基因阳性株红霉素最低抑菌浓度为2～>256mg/L。结论pbp2B基因突变是本地区Sp青霉素耐药机制的主要遗传学基础之一;突变株中,A类突变率最高,表现对青霉素、二代头孢不敏感;ermA、ermB和mefA3种红霉素耐药基因单独或共同表达     

A single intramuscular dose of ceftriaxone changes nasopharyngeal bacterial flora in children with acute otitis media

The increasing prevalence of drug-resistant bacteria is attributed to the extensive use of antibiotics, which causes selective pressure on the nasopharyngeal bacterial flora. Shortened courses of antibiotics have been proposed to decrease the development of resistant strains. We determined the effect of a single intramuscular dose of ceftriaxone (50 mg/kg) on the nasopharyngeal bacterial flora in 167 children (median age 13 mo) with acute otitis media. Nasopharyngeal samples for bacterial culture were obtained before and 5 d after treatment with ceftriaxone. Before treatment, Moraxella catarrhalis was isolated in 99 (59%) children, Streptococcus pneumoniae in 87 (52%), and Haemophilus influenzae in 53 (32%). After treatment, M. catarrhalis was found in 62 (37%) children, which constitutes a 37% decrease in the colonization rate by this pathogen (p < 0.001). S. pneumoniae was isolated in 50 (30%; 43% decrease) and H. influenzae in 17 (10%; 68% decrease) children after treatment (p < 0.001 for both). Before treatment, 60% of pneumococcal isolates were sensitive to penicillin, 26% were of intermediate susceptibility, and 14% were penicillin-resistant. Eradication of S. pneumoniae occurred mainly in children with penicillin-sensitive isolates. As a consequence, only 24% of pneumococcal isolates that remained after treatment were sensitive to penicillin, 59% were penicillin-intermediate, and 16% were penicillin-resistant. A single dose of ceftriaxone resulted in significant changes in the nasopharyngeal bacterial flora, increasing the relative prevalence of pneumococcal strains with decreased susceptibility to penicillin.     

Epidemiology of pneumococcal infections in Swedish children

OBJECTIVE: This paper provides an overview of pneumococcal infections in Swedish children. METHOD: Data supplied by the Swedish Institute for Infectious Disease Control (SMI) provided information on invasive pneumococcal isolates and on isolates with reduced susceptibility to penicillin. Disease burden was estimated from data collected in northern Stockholm and Malm?hus County. Results: Only 3-6% of the total number of invasive pneumococcal isolates came from children 0-15 years of age. Predominant serotypes in descending frequency were 7, 6, 14, and 23. Strains from all sources with reduced sensitivity to penicillin (MIC > or = 0.5 mg/l) were found in 3% of children and varied between 0.2% and 11%, with the highest value found in Southern Sweden (predominating strains were 9, 19, 15, 6, and 23). A 10-year review of all cases of meningitis in Northern Stockholm reflected an incidence of 10/100,000 (0-2 years) or 5.8/100,000 (0-5 years), with severe sequelae occurring in 20% of children. This information can be used to predict an annual incidence of 30 cases of meningitis in Sweden. CONCLUSION: The large proportion of serotype 7 among invasive isolates is distressing since this serotype is not represented in the present 7- and 9-valent protein-conjugated vaccines under development. However, the heptavalent vaccine, including serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F would (at a serotype level) provide coverage against 83% of the resistant isolates in Southern Sweden.     

Epidemiology of pneumococcal infections in Swedish children

Objective: This paper provides an overview of pneumococcal infections in Swedish children.
Method: Data supplied by the Swedish Institute for Infectious Disease Control (SMI) provided information on invasive pneumococcal isolates and on isolates with reduced susceptibility to penicillin. Disease burden was estimated from data collected in northern Stockholm and Malmöhus County. Results: Only 3–6% of the total number of invasive pneumococcal isolates came from children 0–15 years of age. Predominant serotypes in descending frequency were 7, 6, 14, and 23. Strains from all sources with reduced sensitivity to penicillin (MIC 0.5 mg/l) were found in 3% of children and varied between 0.2% and 11%, with the highest value found in Southern Sweden (predominating strains were 9, 19, 15, 6, and 23). A 10-year review of all cases of meningitis in Northern Stockholm reflected an incidence of 10/100000 (0–2 years) or 5.8/100000 (0–5 years), with severe sequelae occurring in 20% of children. This information can be used to predict an annual incidence of 30 cases of meningitis in Sweden.
Conclusion: The large proportion of serotype 7 among invasive isolates is distressing since this serotype is not represented in the present 7- and 9-valent protein-conjugated vaccines under development. However, the heptavalent vaccine, including serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F would (at a serotype level) provide coverage against 83% of the resistant isolates in Southern Sweden.