广州地区儿童鼻咽部流感嗜血杆菌带菌及耐药性研究

目的　了解广州地区儿童鼻咽部流感嗜血杆菌 (Hi)带菌情况及耐药性。方法　 2 0 0 1年 2～ 3月份选择广州市两家幼儿园健康儿童和我院门诊急性上呼吸道感染患儿各 15 0例 ,取其鼻咽分泌物进行Hi分离培养 ,比较两组儿童鼻咽部Hi带菌率。用Etest法检测Hi对 9种抗生素的耐药性。结果　健康儿童和急性上呼吸道感染患儿鼻咽部Hi的带菌率分别为 2 4 7% (37/ 15 0 )和 2 2 7% (34/ 15 0 ) ,差别无显著性意义 (χ2 =0 0 7,P >0 0 5 )。 6 1株健康儿童鼻咽部Hi和 2 5 8株急性上呼吸道感染患儿鼻咽部Hi对阿莫西林 /棒酸、头孢曲松、头孢呋辛全部敏感 ,健康儿童鼻咽部Hi对氨苄西林、头孢克洛、复方新诺明、氯霉素、四环素的耐药率低于急性上呼吸道感染患儿。结论　急性上呼吸道感染患儿鼻咽部Hi的耐药率高于健康儿童 ,临床治疗Hi感染应选用广谱头孢菌素或青霉素类抗生素加棒酸的复合药物。     

小儿急性呼吸道感染流感嗜血杆菌耐药性研究

为了解上海地区小儿急性呼吸道感染 (ARTIs)时流感嗜血杆菌(Hi)的分离率、产酶率以及b型Hi(Hib)感染的情况 ,并了解Hi对8种常用抗菌药物的耐药性 ,收集812例呼吸道感染患儿的鼻咽分泌物进行Hi分离培养 ,以Nitrocefin纸片法测定β_内酰胺酶的产生率 ,以玻片凝集法分离出b型株 ,用Kirbry_Bauer(KB)法和E_test法测定Hi对8种抗菌药物的耐药率。结果显示 ,Hi分离率24.7 %,其中Hib占19% ;平均β_内酰胺酶产生率9 % ,其中Hib产酶率36.8 % ,明显高于非Hib产酶率2.5 %(P<0.01)。Hi对第2、第3代头孢类抗生素、阿莫西林/克拉维酸均十分敏感 ,对氯霉素、氨苄西林的耐药率分别为11.5%和9.5 % ,而对四环素、复方新诺明(SMZco)的耐药率分别达到16.1 %和45.6%。提示Hi是小儿ARTIs的重要病原菌之一 ,Hi对氨苄西林、氯霉素、四环素和SMZco的耐药在增加 ,产β_内酰胺酶是Hi耐药的重要机制 ,而Hib的产酶率显著高于非Hib株     

苏州地区2011-2012年儿童感染流感嗜血杆菌耐药新特征

目的了解苏州地区儿童感染流感嗜血杆菌（Haemophilusinlfuenzae,Hi）的耐药变迁及特点。方法对2011年1月至2012年6月临床分离的1222株Hi,用K-B法进行药敏试验,头孢硝噻吩显色法进行β内酰胺酶测定,根据结果分为4种耐药模式：①β内酰胺酶阳性菌（头孢呋新耐药株除外）;②β内酰胺酶阴性氨苄西林耐药菌（BLNAR）;③头孢呋新耐药菌;④其他耐药菌。结果本地区儿童感染Hi对氨苄西林、复方新诺明、头孢克洛、四环素、氯霉素、阿奇霉素、头孢呋新、氨苄西林/舒巴坦的耐药率分别为32.7%、76.7%、27.4%、14.3%、10.2%、8.4%、6.9%、4.3%。其中①~④组耐药模式的检出率分别为29.0%、2.6%、6.9%、41.2%。多重耐药菌主要分布在①和②组,分别占该组的67.5%和81.3%。阿奇霉素、四环素、氯霉素对BLNAR和头孢呋新耐药的Hi具有较高的抗菌活性。β内酰胺酶的总检出率为30.8%。头孢呋新、头孢克洛、氨苄西林/舒巴坦、复方新诺明的耐药率在β内酰胺酶阳性的氨苄西林耐药菌和β内酰胺酶阴性的氨苄西林耐药菌中有显著差别。结论     

氨苄西林耐药流感嗜血杆菌的基因分型研究

目的了解2000-2003年北京、上海、广州细菌耐药监测项目中,小于5岁呼吸道感染儿童鼻咽部携带氨苄西林（AMP）耐药流感嗜血杆菌（Haemophilus influenzae,Hi）的分子流行病学情况。方法对上述呼吸道感染儿童鼻咽部分离的899株Hi进行AMP敏感性检测,筛选出74株AMP耐药Hi,采用巢式PCR荚膜分型和玻片凝集法,对AMP耐药菌株进行b型Hi（Haemophilus influenzaetypeb,Hib）检测,并用脉冲电场凝胶电泳（pulsed—field gel electrophoresis,PFGE）和多重PCR两种方法,对AMP耐药菌株进行基因分型。结果74株AMP耐药Hi中,有2株Hib（占2．7％）。PFGE分型74株AMP耐药Hi中有38种基因型,具有克隆传播趋势的有5型,包括41株Hi（占55．4％）。其中菌株数最多的为A型,有18株,占24．3％,以2002年上海地区为主。多重PCR分型结果有31型,多重PCR与PFGE分型结果一致率为63．5％。结论北京、上海、广州三地区四年内小于5岁的呼吸道感染儿童鼻咽部携带的AMP耐药Hi有55．4％的菌株存在克隆传播。     

儿童呼吸道卡他莫拉菌分离株耐药性与BRO基因分型研究

目的调查儿童呼吸道卡他莫拉菌分离株产β内酰胺酶情况和耐药性,以及菌株BRO酶基因特征。方法2011年6月至2012年9月,从儿童呼吸道分离卡他莫拉菌401株;用微量肉汤稀释法测定常用抗生素最低抑菌浓度,用Nitroceifn纸片法检测β-内酰胺酶,用PCR扩增结合限制性内切酶分析方法对分离株进行BRO基因分型。结果401株卡他莫拉菌的β-内酰胺酶产酶率为96.5%（387/401）;产酶株对氨苄西林、头孢克洛、头孢呋辛的MIC50、MIC90和耐药率明显高于非产酶株,差异有统计学意义（P<0.05）;产酶株BRO基因阳性率为99.2%（384/387）,其中BRO-1型为93.0%,BRO-2型为7.0%;BRO-1+菌株对氨苄西林、头孢克洛、头孢呋辛和阿齐霉素的MIC50和MIC90明显高于BRO-2+菌株。结论儿童呼吸道卡他莫拉菌分离株β-内酰胺酶产酶率高,产酶株主要携带BRO-1基因,其对部分β-内酰胺类和大环内酯类抗生素的影响明显高于BRO-2型菌株。     

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.     

2006-2007年苏州地区儿童呼吸道感染流感嗜血杆菌分布及耐药性分析

目的研究苏州地区呼吸道感染患儿流感嗜血杆菌的感染情况及其耐药性。方法对苏州大学附属儿童医院2006年1月至2007年12月间住院的3167例急性呼吸道感染患儿,采用无菌负压吸引法采集新鲜痰液,进行流感嗜血杆菌培养、分离,观察并总结其呼吸道流感嗜血杆菌感染情况及相关因素,采用纸片扩散法(K-B法)进行药敏试验,头孢硝噻酚试验检测β-内酰胺酶。结果3167例呼吸道感染患儿分离到140株流感嗜血杆菌,总分离率4.4%;感染多见于婴幼儿;四季检出率不同(P<0.01),以2月～6月检出率较高;男性感染率高于女性(P<0.01)。31.4%的分离株产β-内酰胺酶,对氨苄西林、复方新诺明、氯霉素、头孢克洛、头孢他啶、四环素、氨苄西林/舒巴坦耐药率分别为29.6%～31.9%、66.2%～73.9%、19.7%～15.9%、2.8%～14.5%、2.8%～0、28.2%～2.9%、4.2%～1.4%。未发现对头孢呋辛、头孢曲松、亚胺培南、阿奇霉素、环丙沙星的耐药株。结论苏州地区呼吸道感染患儿流感嗜血杆菌的感染率与季节有关,以婴幼儿感染为主,有性别差异。流感嗜血杆菌β-内酰胺酶阳性率较高并呈上升趋势,对氨苄西林、复方新诺明及...     

流感嗜血杆菌耐药基因及耐药机制分析

目的从分子水平了解南京地区儿童流感嗜血杆菌(Hi)对氨苄西林的耐药状况。方法对158株Hi临床分离株进行β-内酰胺酶检测,PCR扩增β-内酰胺酶的TEM及ROB编码基因,并克隆到T载体中作核酸序列测定与分析。结果本地区儿童感染Hi对氨苄西林的耐药率为41.77％。β-内酰胺酶阳性率为40．51％。TEM基因阳性89株,ROB阳性基因1株。63株耐氨苄西林且β-内酰胺酶阳性,耐药性主要是由于产生β-内酰胺酶和TEM基因。2株耐氨苄西林且β-内酰胺酶阴性。1株β-内酰胺酶阳性,但未检测到TEM或ROB基因。结论本地区儿童感染Hi对氨苄西林的耐药情况不容乐观,耐药机制主要是产生β-内酰胺酶,且以TEM型为主。     

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目的分析呼吸道感染患儿鲍曼不动杆菌的感染情况及其耐药性。方法对2009年1月至2010年12月在苏州大学附属儿童医院呼吸科住院的3529例急性呼吸道感染患儿,采用无菌负压吸引法采集新鲜痰液,进行鲍曼不动杆菌培养、分离,并采用定量MIC法进行药敏试验,观察及分析呼吸道鲍曼不动杆菌感染情况及相关因素。结果 3529例急性呼吸道感染患儿分离到1523株致病菌,其中鲍曼不动杆菌44株,占2.89%;在不同的性别、年龄组感染率无差别;四季分布不同,以夏秋季节多见。鲍曼不动杆菌对氨苄西林、呋喃妥因、头孢唑林的耐药率为100%,对头孢他啶、头孢噻肟、头孢吡肟的耐药率上升,未发现对头孢哌酮舒巴坦、妥布霉素、左氧氟沙星、氨苄西林舒巴坦、阿米卡星、亚胺培南的耐药菌株。结论苏州儿童医院急性呼吸道感染患儿鲍曼不动杆菌的感染率与季节有关,无性别、年龄差异;对氨苄西林、呋喃妥因、头孢唑林耐药,对第三、四代头孢菌素的耐药率上升。     

新生儿流感嗜血杆菌感染前瞻性多中心流行病学调查与病例对照研究

目的：了解新生儿流感嗜血杆菌( Haemophilus influenza,Hi)感染发生情况、流行菌株生物学分型和菌株耐药背景以及Hi新生儿肺炎临床基本特征。方法采用多中心前瞻性流行病学断面研究方法,对中国川西地区4家医院0~28 d入院初步诊断为新生儿感染性肺炎患儿痰液进行细菌培养,对Hi流行菌株进行生物学分型、PCR鉴定和药敏试验;以出院诊断为新生儿感染性肺炎的Hi分离阳性者为病例组,按1∶1提取同期住院新生儿肺炎Hi分离阴性者为对照组进行病例对照研究。结果2014年11月至2015年10月参加调查的4家医院入院诊断为新生儿感染性肺炎患儿757例,痰培养送检率95.51％(723/757),痰培养病原菌总阳性率15.63％(113/723);Hi阳性率1.94％(14/723),占新生儿呼吸道分离病原菌的12.39％(14/113)。全部14株Hi经PCR鉴定均为不可分型Hi;生物学分型Ⅰ型57.1％(8/14)、Ⅲ型14.3％(2/14)、Ⅳ型28.6％％(4/14);分离的14株流行菌株β-内酰胺酶阳性率35.7％(5/14),β-内酰胺酶阴性氨苄西林耐药7.1％(1/14),β-内酰胺酶阳性氨苄西林耐药35.7％(5/14),头孢呋辛耐药和中介率均为14.2％(2/14),头孢克洛耐药率35.7％(5/14),氧氟沙星耐药率21.4％(3/14),未发现阿莫西林克拉维酸和头孢噻肟耐药菌株。对10例出院诊断为新生儿肺炎的Hi阳性病例进行1∶1配对分析,结果显示病例组与对照组在一般情况、临床主要症状、肺部体征、X线胸片表现以及白细胞分类和C-反应蛋白水平等方面差异均无统计学意义(P>0.05)。结论川西地区新生儿Hi感染流行菌株全部为不可分型,生物学分型为Ⅰ型、Ⅲ型和Ⅳ型;新生儿未分型Hi肺炎临床表现与其感染性肺炎并无明显差异。     

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??Objective To investigate the antibiotic resistance patterns and epidemiological features of Haemophilus influenzae??HI?? strains??and to provide reference for choosing antibiotics in clinical treatment. Methods A total of 546 strains were identified from 2007 to 2014 in Children’s Hospital??Zhejiang University School of Medicine and 98.7% were isolated from respiratory tract specimens. Three hundred and forty-eight isolates??63.7%?? were from boys and the male-female ratio was 1.76??1. The age of the infected children ranged from 7 days to 13 years. Haemophilus influenza strains were cultured in Haemophilus selective medium. All strains were identified with ?? factor and ?? factor requirement test and the drug-sensitivities tests were performed with disk diffusion method. Cefinase was used to detect β-lactamase. Results Most of the strains??331 isolates??60.6%?? were isolated in spring??while only 23??4.2%?? were isolated in autumn. The β-lactamase positive strains increased annually and the total rate was 26.7%??146???? and 28.0%??153 strains?? were resistant to ampicillin. The multi-resistance strains were 60??11.0%?? and the major multi-resistance type was those resistant to ampicillin??trimethoprim-sulfamethoxazole and clarithromycin at the same time??and the multi-resistance rate in β-lactamase-positive strains were significantly higher than that in β- lactamase- negative strains??χ2??145.1??P??0.005??. Conclusion Most of the Haemophilus influenzae strains are isolated from respiratory samples in children younger than 1 year old in our hospital??and the peak months were February??March??April and May. The resistance rate to ampicillin of HI strains has increased annually??whereas to the second generation of cephalosporin??HI strains are still sensitive and they can be used in clinical treatment as the first choice.     

Antimicrobial susceptibility of Haemophilus influenzae among children in Beijing, China, 1999-2000

A study on the nasopharyngeal carriage and antimicrobial susceptibility of Haemophilus influenza among children was conducted in Beijing Children's Hospital from April to May 2000. The study included 292 children between 1 and 60 mo of age with acute upper respiratory tract infection. Nasopharyngeal swabs from these patients were cultured, and 105 Haemophilus influenzae strains were isolated, 3 of which were type b. Antibiotic susceptibility of the strains was determined using disk diffusion and E-tests and the results compared with those of isolates from children with pneumonia in 1999. The carriage rate of Haemophilus influenzae was 36.0% (105/292). It was found that 4.8% and 1.0% of isolates were resistant to ampicillin and cefaclor, respectively, and 5.7%, 16.2% and 77.1% were resistant to chloramphenicol, tetracycline, and sulphamethoxazole/ trimethoprim, respectively. Amoxicillin/clavulanic acid, cefuroxime, ceftriaxone, azithromycin, and clarithromycin were uniformly active to all strains. Compared with the data from 1999, there was a significant increase in resistance to tetracycline (from 12.7% in 1999 to 16.2%) and sulphamethoxazole/trimethoprim (from 40.5% in 1999 to 77.1%).

Conclusion : H. influenzae isolates from outpatients in Beijing Children's Hospital had low ampicillin resistance and were sensitive to amoxicillin/clavulanic acid. Sulphamethoxazole/ trimethoprim resistance rates increased rapidly compared with those in the 1999 data. Further surveillance investigations are important for the choice of empiric therapy of acute respiratory tract infection.     

流感嗜血杆菌患儿分离株的血清分型和耐药模式研究

目的　了解流感嗜血杆菌患儿分离株的血清分型和体外耐药模式。方法　对本院2 0 0 1年 8月～ 2 0 0 2年 7月经apiNH卡鉴定的 2 4 7株流感嗜血杆菌 ,用玻片凝集法进行血清分型 ,用Kirby Bauer法检测其对 13种抗生素的敏感性 ,并用E test法检测氨苄西林的最低抑菌浓度。用头孢硝噻酚法检测 β内酰胺酶。 结果　不可分型流感嗜血杆菌 15 3株 ,占细菌总数 6 1 9% ,可分型菌株94株 ,占 38 1% ;可分型株在男女患儿中的分离率分别为 4 3 2 % (70 / 16 2 )和 2 8 2 % (2 4 / 85 ) ,差异有显著性 (χ2 =3 95 ,P <0 0 5 )。可分型菌株中d型构成比达 90 4 % ,b型仅 1 1%。 4 1株菌株(16 6 % )产生 β内酰胺酶。 2 33株菌株成功完成药敏试验 ,结果显示 :85 4 %的菌株对氨苄西林敏感 ,对头孢克洛、头孢噻肟、头孢曲松、亚胺培南、利福平、克拉霉素和氯霉素的敏感率分别高达98 7%、99 6 %、99 6 %、99 6 %、98 7%、91 0 %和 90 6 %。所有的菌株均对氨苄西林 /舒巴坦、阿莫西林 /克拉维酸和氧氟沙星敏感。菌株对甲氧苄啶 磺胺甲基异恶唑的耐药率最高 ,达 4 5 9%。可分型株对氨苄西林和甲氧苄啶 磺胺甲基异恶唑的耐药率显著高于不可分型株。β内酰胺酶阳性菌多重耐药率显著高于阴性菌 (χc2 =14 6 8,P <0 0 0 1     

Invasive Haemophilus influenzae type B diseases in Bangladesh, with increased resistance to antibiotics

OBJECTIVE: To determine the prevalence, age-group distribution, serotype, and antibiotic susceptibility patterns of invasive Haemophilus influenzae type b (Hib) isolates in Bangladeshi children because data regarding Hib diseases in developing countries are scarce, which has led to delay of the introduction of Hib vaccine in these countries. METHODS: Children diagnosed with meningitis (n = 1412) and pneumonia (n = 2434) were enrolled in this surveillance study for Hib invasive diseases. Cerebrospinal fluid (CSF) and blood specimens, and the subsequent isolates, were processed using standard procedures. RESULTS: During 1993 to 2003, 455 H influenzae strains were isolated from patients with meningitis (n = 425) and pneumonia (n = 30), and an additional 68 Hib meningitis cases were detected by latex agglutination (LA) testing. Overall, 35% of pyogenic meningitis cases were a result of H influenzae, 97.1% of which were Hib. Most (91.4%) cases occurred during the first year of life. Resistance to ampicillin, chloramphenicol, and cotrimoxazole was 32.5%, 21.5%, and 49.2%, respectively. There was a trend toward increasing resistance for all three drugs. Resistance to ampicillin and chloramphenicol was almost universally coexistent and was associated with increased sequelae compared with the patients infected with susceptible strains (31% [23/75] vs 11% [21/183]; P <.001). CONCLUSION: Hib is the most predominant cause of meningitis in young Bangladeshi children. Resistance to ampicillin and chloramphenicol and the high cost of third-generation cephalosporin highlight the importance of disease prevention through vaccination against Hib.     

Direct detection of the multidrug resistance genome of Haemophilus influenzae in cerebrospinal fluid of children: implications for treatment of meningitis

BACKGROUND: Multidrug resistance (MDR), specifically to ampicillin and chloramphenicol, has complicated the treatment of Haemophilus influenzae type b (Hib) meningitis. This is worsened by use of prior antibiotics, which limits identification of the causative agent by culture and increases reliance on antigen detection. OBJECTIVE: We aimed to develop a PCR assay for detecting the family of Haemophilus integrating and conjugative elements (ICEs) represented by ICEHin1056 among antibiotic resistant Hib, and then apply this directly to CSF to diagnose Hib meningitis and predict organism susceptibility, irrespective of culture results. STUDY DESIGN: Primers specific for orf 51 of ICEHin1056 were designed and multiplexed with Bex primers, specific for H. influenzae, and tested on culture positive and negative cases. RESULTS: Of 73 Hib isolates, orf 51 PCR amplicons, predicting the presence of ICEs, were found in all 33 MDR isolates while only in 1 of 33 sensitive strains. The remaining 7 ampicillin susceptible, chloramphenicol and tetracycline resistant strains did not produce a PCR product to orf 51. PCR amplification from CSF specimens of these culture positive cases produced identical results with 100% and 97% positive and negative predictive values, respectively. Multiplex PCR to detect Bex and orf 51 identified another 16 MDR Hib cases among 81 culture-negative CSF samples. CONCLUSIONS: Direct PCR for orf 51 in CSF identified resistance pattern of 51% more Hib strains than culture alone (110 versus 73). The ability to detect MDR, in culture negative Hib meningitis cases has significant implications for better directing antibiotic treatment of meningitis cases and thus for preventing disability and death.     

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??Abstract??Objective??To investigate antibiotic resistance and mechanism of antibiotic resistance of Haemophilus influenzae ??HI?? in children with acute respiratory tract infection in Suzhou. To determine beta-lactamase genes of Haemophilus influenzae?? possible genetic mutation and the possible relationship between minimal inhibitory concentrations??MICs?? of beta-lactamases antibiotic and genetic mutation. Methods??The susceptibility of 135 clinical isolates of Haemophilus influenzae were calculated using E-tests?? and beta-lactamases of these stratins were detected. Besides?? the beta-lactamases genes were detected by net-polymerase chain reaction ??n-PCR?? followed by DNA sequencing. The sequences of drug resistance genes were compared with the published sequence in GeneBank. Results??The beta-lactamase positive rate of HI was 31.1%. The MIC90 and MIC50 of HI to ampicillin??ampicillin/sulbactam??cefaclor and chloramphenicol were??32 μg/mL??1 μg/mL??????2 μg/mL?? 0.75 μg/mL??????24 μg/mL??3 μg/mL?? and ??8 μg/mL??0.5 μg/mL?? respectively. Among the isolated 135?? TEM genes were detected in 53 HI. Beta-lactamase geneTEM was detected in 39.3%of HI??No ROB gene was detected. About 28.3% of TEM gene had been mutated. The mean minimal inhibitory concentration of beta-lactamases antibiotic in HI that had mutant TEM genes was higher than that of no-mutant TEM gene. Conclusion Ampicillin resistance in HI influenzae isolates from children in this region is challenging??The resistance mechanism of beta-lactamase antibiotics is of production beta-lactamase TEM and 28.3% of TEM gene has been mutated. The production of TEM and its mutation is one of the most important factors that leads to the high resistance to beta-lactamase antibiotics.     

Antimicrobial resistance of nasopharyngeal isolates of Streptococcus pneumoniae and Haemophilus influenzae from children in the Central African Republic

BACKGROUND: To assist the Central African Republic (CAR) develop national guidelines for treating children with pneumonia, a survey was conducted to determine antimicrobial resistance rates of nasopharyngeal isolates of Streptococcus pneumoniae (SP) and Haemophilus influenzae (HI). Secondary purposes of the survey were to identify risk factors associated with carriage of a resistant isolate and to compare the survey methods of including only children with pneumonia vs. including all ill children. METHODS: A cross-sectional survey of 371 ill children was conducted at 2 outpatient clinics in Bangui, CAR. RESULTS: In all 272 SP isolates and 73 HI isolates were cultured. SP resistance rates to penicillin, trimethoprim-sulfamethoxazole (TMP-SMX), tetracycline and chloramphenicol were 8.8, 6.3, 42.3 and 9.2%, respectively. All penicillin-resistant SP isolates were intermediately resistant. HI resistance rates to ampicillin, TMP-SMX and chloramphenicol were 1.4, 12.3 and 0%, respectively. The most common SP serotypes/groups were 19, 14, 6 and 1; 49% of HI isolates were type b. History of antimicrobial use in the previous 7 days was the only factor associated with carriage of a resistant isolate. Resistance rates were similar among ill children regardless of whether they had pneumonia. CONCLUSIONS: Resistance rates were low for antimicrobials recommended by the World Health Organization for children with pneumonia. We recommended TMP-SMX as the first line treatment for pneumonia in CAR because of its low cost, ease of dosing and activity against malaria.     

Ampicillin-chloramphenicol-resistant Haemophilus influenzae: plasmid-mediated resistance in bacterial meningitis

A 4-month-old infant with congenital heart disease and sepsis and arthritis, and subsequently meningitis, caused by an antibiotic-resistant strain of Haemophilus influenzae type b, failed to respond to sequential therapy with ampicillin and trimethoprim/sulfamethoxazole. Following treatment with ceftizoxime, the infant was well for 42 days, until he returned to the hospital and died. A total of 10 Haemophilus influenzae type b isolates, all outer membrane protein subtype 51, was isolated from the pretreatment blood and synovium, cerebrospinal fluid and subdural fluids, and the petrous pyramids at autopsy. Pretreatment isolates had no detectable plasmid DNA, chloramphenicol acetyltransferase or beta-lactamase; the minimal inhibitory concentration for ampicillin (AM) and chloramphenicol (CM) was 0.2 and 0.8 microgram/ml, respectively. However, all cerebrospinal fluid isolates had a 42-44 mD plasmid and produced chloramphenicol acetyltransferase and beta-lactamase; the minimal inhibitory concentration of these isolates to AM and CM were 12.5 and 25 micrograms/ml, respectively, and were also resistant to tetracycline and sulfonamide. Resistance to AM and CM was cotransferred by filter-mating conjugation at a frequency of one to two transconjugants per 10(5) to an Rd haemophilus recipient. Posttreatment isolates from the petrous pyramids also were resistant to AM and CM and produced chloramphenicol acetyltransferase and beta-lactamase activity, but had no plasmid DNA. These findings and data from genetic studies suggested that plasmid-bearing antibiotic-resistant Haemophilus influenzae type b was selected from a heterogenous population, and that the AM/CM resistance transposons were incorporated into the bacterial chromosome.     

Pharyngeal colonization with Haemophilus influenzae type b among healthy Turkish infants and children

BACKGROUND: An absence of Haemophilus influenzae type b (Hib) disease surveillance and epidemiological data on the pharyngeal carriage of Turkish children causes delay in the introduction of conjugated Hib vaccination into proposed national vaccination programs. METHODS: Oropharyngeal cultures were obtained from 1404 healthy infants and children. Six healthy child clinic (HCC), 11 day-care centers (DCC) and seven elementary schools (ES) were randomly selected in seven different counties at the Anatolian side of Istanbul between January and April 2000. RESULTS: Haemophilus influenzae was isolated from 315 (22.8%) of all participants and 98 (31%) isolates were serotype b. The carriage rate for Hib was higher in children at DCC (43 out of 448, 9.6%) and ES (46 out of 504, 9.1%) compared to infants 0-24 months of age (nine out of 430, 2.1%) presented to HCC. All Hib isolates were susceptible to azithromycin, chloramphenicol and cefotaxime. Beta-lactamase production was detected in only one isolate. Trimethoprim-sulfamethoxazole resistance was found in 8.5% of Hib isolates. Multivariate analysis showed that DCC and ES attendance were independent predictors of Hib carriage. CONCLUSION: A significant proportion of healthy Turkish children was shown to be colonized with Hib. The burden of invasive Hib infections should be determined in order to evaluate the Hib conjugated vaccine as a part of a routine immunization program in Turkey.