HEp-2-adherent Escherichia coli strains associated with acute infantile diarrhea,São Paulo,Brazil

In this paired case-control study of infants with diarrhea in São Paulo, we examined the association between HEp-2–adherent Escherichia coli strains and diarrhea. We tested isolates from stool specimens of infants with diarrhea and matched controls in an HEp-2 cell adherence assay; we then hybridized isolates with DNA probes and identified enteropathogenic E. coli (EPEC), enteroaggregative E. coli (EAEC), and diffusely adherent E. coli (DAEC). From 100 patient-control pairs, we isolated 78 HEp-2–adherent strains; of these, 61 strains were single pathogens identified in stools of infants with diarrhea. While typical EPEC was significantly associated with diarrhea (p<0.001), EAEC was more frequently associated with diarrhea in clinical cases (20%) compared with healthy controls (3%) (p<0.001). Atypical EPEC, showing a localized adherence-like pattern, was also more common in patients than controls (p>0.1). DAEC was isolated with equal frequency from patients and controls (p>0.1).     

Characterization of Salmonella enterica and detection of the virulence genes specific to diarrheagenic Escherichia coli from poultry carcasses in Ouagadougou, Burkina Faso

One hundred chicken carcasses purchased from three markets selling poultry in Ouagadougou, Burkina Faso, between June 2010 and October 2010 were examined for their microbiological quality. The presence of Salmonella was investigated using standard bacteriological procedures, and the isolates obtained were serotyped and tested for antimicrobial susceptibility. The presence of virulence-associated genes of the five main pathogroups of diarrheagenic Escherichia coli-Shiga toxin-producing E. coli (STEC), enteropathogenic E. coli (EPEC), enteroaggregative E. coli (EAEC), enterotoxigenic E. coli, and enteroinvasive E. coli-was investigated using 16-plex polymerase chain reaction (PCR) on the mixed bacterial cultures from the poultry samples. Of the 100 chicken carcasses studied, 57 were contaminated by Salmonella; 16 different serotypes were identified, the most frequent being Salmonella Derby, found in 28 samples. Four Salmonella strains were resistant to tetracycline, and two were resistant to streptomycin. Based on the PCR detection of the virulence genes, in total, 45 carcasses were contaminated by three pathogroups of E. coli: STEC, EPEC, or EAEC. The STEC and EPEC virulence genes were detected on six and 39 carcasses, respectively. EAEC virulence genes were only detected in combination with those of EPEC (on 11 carcasses) or STEC (on two carcasses). The STEC-positive carcasses contained the genes stx(1), stx(2), eaeA, escV, and ent in different combinations. None of the EPEC-positive carcasses contained the bfp gene, indicating that only atypical EPEC was present. EAEC virulence genes detected were aggR and/or pic. The high proportion of chicken carcasses contaminated by Salmonella and diarrheagenic E. coli indicates a potential food safety risk for consumers and highlights the necessity of public awareness of these pathogens.     

Distribution of virulence related genes among enteroaggregative Escherichia coli isolates: using multiplex PCR and hybridization.

The importance of enteroaggregative Escherichia coli (EAEC) strains in public health around the world is becoming increasingly clear. EAEC diagnosis has long been problematic. In this study, the recently designed multiplex PCR based on three plasmid-borne genes (AA probe, aap, and aggR) and DNA hybridization assay with plasmid-derived DNA probes were used for detection of HEp-2 adherent strains. These were isolated from an epidemiologic study of diarrhea in Iran. Using AA and DA probes revealed that 32.4%, 16.2%, 23%, and 28.4% of these isolates were AA, DA, AA/DA, and non-AA/DA, respectively. However, employing multiplex PCR for detection of these isolates, showed that 51.3% of the strains were AA and the rest 48.7% were not AA. While presence of other genes (pet, shf, aggA, aafA) considered to be specific for EAEC were checked among these isolates. The data obtained revealed that except for AA, aap, and aggR, the rest of the virulence related genes are not specific for EAEC isolates and are randomly distributed among adherent isolates. Over all the results obtained here indicated that this multiplex PCR is specific and sensitive assay. Phenotypically adherent strains are divided into two main groups, by use of this multiplex PCR i.e., typical EAEC isolates that carry the three plasmid-borne genes all together and atypical EAEC isolates in which the three genes are not linked together.     

产ESBLs大肠埃希菌的耐药性分析 FREE

目的了解昆明市第一人民医院产超广谱β 内酰胺酶（ESBLs）大肠埃希菌的检出及耐药情况。方法对该院2006年1-12月临床分离的293株大肠埃希菌,用表型确证试验检测ESBLs,K B琼脂纸片扩散法做药物敏感试验。结果293株大肠埃希菌中,检出产ESBLs菌168株（57.34%）。各类标本中,产ESBLs率以痰标本分离株（64.71%）最高,其次为血液（62.50%）和脓液标本（57.14%）;各科室中,产ESBLs率以重症监护室（ICU）分离株（65.22%）最高,其次为内分泌科（65.00%）和肿瘤科（63.33%）。除亚胺培南和阿米卡星外,产ESBLs菌对其他14种常用抗菌药物的耐药率均明显高于非产ESBLs菌(均P<0.01);产ESBLs菌株不仅对青霉素、头孢菌素、氨曲南等抗生素广泛耐药,同时对喹诺酮类、氨基糖苷类、磺胺类等多种抗菌药物耐药,仅对亚胺培南、阿米卡星的耐药率＜5%(分别为0.00%、3.30%)。结论昆明市第一人民医院临床分离大肠埃希菌产ESBLs率较高;产ESBLs菌株对临床常用多种抗菌药物严重耐药,可经验选用的药物十分有限。临床医生应根据病原菌药敏结果合理选用抗菌药物,以提高治疗效果。     

2015―2019年安徽省致泻性大肠埃希菌分型及耐药性分析

  目的  了解安徽省致泻性大肠埃希菌（DEC）的菌群流行特点及耐药趋势，为安徽省DEC腹泻病的诊断和治疗提供科学依据。  方法  采集安徽省2015―2019年腹泻患者粪便样本，采用多重实时荧光定量PCR对细菌进行鉴定与分型，采用微量肉汤稀释法对细菌进行药敏试验。  结果  从6 120份粪便中分离出DEC 557株，主要病原型为:非典型肠聚集性大肠埃希菌（aEAEC）191（34.29%）株，产肠毒素性大肠埃希菌（ETEC）153（27.47%）株，非典型肠致病性大肠埃希菌（aEPEC）108（19.39%）株，典型肠聚集性大肠埃希菌（tEAEC）77（13.82%）株，肠侵袭性大肠埃希菌（EIEC）11（1.97%）株，典型肠致病性大肠埃希菌（tEPEC）3（0.54%）株。药敏检测多重耐药255（45.78%）株；同种病理类型不同年份耐药性存在差异:aEAEC:氨苄西林/舒巴坦（AMS），萘啶酸（NAL），头孢西林（CFZ）；tEAEC:AMS，CFZ，阿奇霉素（AZM）；EPEC（aEPEC，tEPEC）:氨苄西林（AMP），AMS，CFZ；ETEC:NAL，AZM，环丙沙星（CIP）。不同病理类型耐药性存在差异的抗生素有:AMP，AMS，四环素（TET），NAL，红霉素（ERY），氯霉素（CHL），头孢噻肟（CTX），CFZ，庆大霉素（GEN），甲氧苄啶/磺胺甲恶唑（SXT），AZM和CIP。2015―2019年，tEAEC对CFZ，EPEC对AMP，AMS和CFZ，ETEC对NAL和CIP，耐药性呈增强趋势。  结论  本地区DEC流行的主要型别是:aEAEC、ETEC、aEPEC和tEAEC。DEC的耐药情况较严重，常用抗生素AMP、AMS、NAL、CFZ和CIP在不同年份和不同病理类型间，耐药性差异明显，耐药性分析结果为临床合理使用抗生素，遏制抗菌药物耐药性增加提供参考。     

大肠埃希菌表型分布及其耐药性分析

目的调查临床分离的大肠埃希菌产不同β-内酰胺酶株分布情况、表型特征及耐药现状。方法收集某院2007年7月--2008年7月临床分离大肠埃希菌株,用VITEK2Compact对其进行鉴定和17种常用抗菌药物的药敏试验,以高级专家系统软件（AESTM）验证和解释药敏测试结果。结果421株大肠埃希菌中,表型主要分为三类：产超广谱β-内酰胺酶（ESBLs）株、产获得性青霉素酶株和野生株。产ESBLs菌株共249株,占59．14％,其中67株为CTX-M型;产获得性青霉素酶菌株120株,占28．50％;产碳青霉烯酶菌株8株,占1．90％;野生株47株,占11．16％。产酶总阳性率为88．84％（374／421）。主要标本来源为洁净中段尿,分离174株（41．33％）,其次为痰标本101株（23．99％）;而科室来源则比较分散,最多为肾内科39株（9．26％）。各型产酶株的耐药性有很大差异;产ESBLS仍是大肠埃希菌产生耐药性的主要原因,其对大多数β-内酰胺类抗生素的耐药性明显高于产获得性青霉素酶株和野生株（P〈0．05）,并对大多数抗菌药物高度耐药。结论大肠埃希菌产酶率非常高,并存在多种耐药表型,其中以产ESBLs最为常见;产酶株的多重耐药和交叉耐药现象十分严重,应高度重视对产酶株的监控,合理使用抗菌药物,以控制耐药株的产生与扩散。     

临床分离大肠埃希菌耐药性监测

目的了解临床分离大肠埃希菌的耐药性,为临床合理应用抗菌药物提供实验室依据. 方法采用微量稀释法对1 414例临床分离大肠埃希菌进行药物敏感性测定;超广谱β-内酰胺酶(extended spectrum beta-lactamases, ESBLs)检测用微量稀释法初筛,纸片法做确证试验. 结果大肠埃希菌对18种抗菌药物的药敏结果中,耐药率＞30%的抗菌药物多达10种;其中以氨苄西林、氨苄西林/舒巴坦、头孢噻吩、哌拉西林、环丙沙星、复方新诺明、庆大霉素、妥布霉素的耐药率高达＞50%.亚胺培南耐药率最低(2.1%),其次为哌拉西林/他唑巴坦(5.2%).头孢菌素类耐药率有一定的上升趋势;产ESBLs菌株的发生率为25.5%～39.8%,平均为32.7%;产ESBLs菌株对多种抗菌药物的耐药率显著高于非产ESBLs菌株(P<0.05). 结论临床分离大肠埃希菌对多种抗菌药物的耐药率较高,尤其是产ESBLs菌株的高耐药率及多重耐药性更为明显,临床应加强对大肠埃希菌耐药性的监测并防治耐药菌株的传播流行.     

儿科院内临床常见细菌耐药性监测

目的调查儿科临床常见致病菌的耐药性现状。方法药物敏感性试验采用Kirby-Bauer纸片扩散法(苛养菌用浓度梯度法),耐药性数据分析采用WHONET5软件。结果2002年1月~2003年12月共收集儿科医院患者首次分离2 303株,其中革兰阳性菌占29.7%,革兰阴性菌占70.3%;耐甲氧西林金黄色葡萄球菌(MRSA)和耐甲氧西林凝固酶阴性葡萄球菌(MRCNS),分别占金黄色葡萄球菌和凝固酶阴性葡萄球菌的9.7%与67.6%,无万古霉素耐药株;肠球菌耐万古霉素株4.1%;11.9%的肺炎链球菌对青霉素耐药;肠杆菌科细菌对亚胺培南的耐药率最低;产超广谱β-内酰胺酶(ESBLs)的大肠埃希菌和肺炎克雷伯菌株的检出率分别为49.7%和63.1%。结论细菌耐药性仍是目前临床上的严重问题,应重视开展儿科抗感染治疗中耐药性监测工作,同时合理使用抗菌药物以降低耐药性和采取有效措施控制其传播也是非常重要的。     

安徽省临床分离致泻性大肠埃希菌主要流行基因型及同源性分析

目的 了解安徽地区临床分离致泻性大肠埃希菌(DEC)的耐药状况、基因同源性及主要基因型.方法 采用微量肉汤稀释法进行药物敏感性试验,采用多位点序列分型(MLST)和脉冲场凝胶电泳(PFGE)分型进行基因型检测和同源性分析.结果 268株DEC中,57.1％为多重耐药菌,其中肠聚集性大肠埃希菌(EAEC)118株,肠毒素...     

抗菌药物对肠球菌属细菌体外抗菌活性

目的了解抗菌药物对某院临床分离肠球菌属细菌的体外抗菌活性。方法对2013年6月—2014年7月该院临床各科室送检标本分离的188株肠球菌属细菌进行细菌鉴定及药物敏感试验。结果 188株肠球菌属细菌其中屎肠球菌119株、粪肠球菌60株、鸟肠球菌9株,主要分布在尿和血标本,分别占34.57%和19.15%。未检出对达托霉素及利奈唑胺耐药的肠球菌属细菌;屎肠球菌对万古霉素的耐药率为1.68%,对青霉素、氨苄西林、高浓度庆大霉素、红霉素、左氧氟沙星的耐药率均70%;除四环素外,粪肠球对其他抗菌药物的耐药率均低于屎肠球菌,粪肠球对青霉素、氨苄西林耐药率较低,分别为16.67%,13.33%。结论达托霉素对该院肠球菌属细菌具有良好的抗菌效果。     

大肠埃希菌血流分离株的耐药特点分析

目的 对大肠埃希菌血流分离株的耐药特点进行分析.方法 收集南昌大学第二附属医院2005年1月-2011年12月从血液分离的大肠埃希菌,使用全自动微生物分析仪对大肠埃希菌进行菌种鉴定和药敏试验,超广谱β-内酰胺酶(ESBLs)的检测采用双纸片扩散法;头孢哌酮/舒巴坦和美罗培南的药敏试验采用K-B法.结果 112株血液分离的大肠埃希菌主要来自肝胆疾病的患者,占22.3％,其次为泌尿系统疾病,占13.4％,血液系统疾病占9.8％;检出55株产ESBls菌株,检出率为48.2％;产ESBLs大肠埃希菌对抗菌药物的耐药率较高,对5种药物的耐药率＞50.0％,但也有5种被测抗菌药物的耐药率＜20.0％,所有被测菌株对亚胺培南和美罗培南全部敏感,对阿米卡星、哌拉西林/他唑巴坦和头孢哌酮/舒巴坦的耐药率分别为7.3％、10.9％、10.9％,非产ESBLs株对8种被测抗菌药物的耐药率＜10.0％.结论 血液分离的大肠埃希菌主要来自患有肝胆疾病的患者,产ESBLs菌株检出率较高.     

某县级医院2012—2014年不同临床标本分离大肠埃希菌ESBLs检出率及其耐药性

目的分析某山区县级医院大肠埃希菌临床感染分布及耐药性,为该区域临床合理治疗大肠埃希菌感染提供依据。 方法对2012-2014年某院临床送检的各类标本进行细菌培养、菌株鉴定与药敏试验,超广谱β 内酰胺酶(ESBLs)检测用微量稀释法初筛,纸片扩散法做确证试验;采用 WHONET 5.6及SPSS 19.0软件对数据进行统计分析。 结果271株大肠埃希菌, 主要分离自中段尿（占26.94%）。产ESBLs大肠埃希菌检出率为49.82%,以痰标本检出率最高（56.52%）,但不同标本分离的大肠埃希菌中产ESBLs菌株检出率比较,差异无统计学意义（P＞0.05）。药敏结果显示,对青霉素类耐药率最高（＞90%）,对头孢噻吩和头孢呋辛的耐药率＞75%,对阿米卡星和哌拉西林/他唑巴坦敏感性较好（耐药率＜10%）,未发现对碳青霉烯类抗生素耐药的大肠埃希菌,产ESBLs株对大多数抗菌药物的耐药率高于非产ESBLs株。结论分离大肠埃希菌的标本主要来自中段尿,产ESBLs菌株耐药性更高。     

2008—2010年某院临床主要病原菌分布及耐药性变迁

目的探讨某院临床近年主要病原菌分布及耐药性,为临床合理用药提供依据。方法收集该院2008年1月-2010年12月分离自门诊及住院患者的病原菌资料,对其构成及耐药性作统计分析。结果共分离病原菌7 008株,其中革兰阴性菌3 961株（56.52％）,革兰阳性菌1 582株（22.57％）,真菌1 465株（20.91％）;居前3位的病原菌依次为白假丝酵母菌（1 015株,15.00%）、铜绿假单胞菌（906株,12.93%）、大肠埃希菌（874株,12.47%）。2008-2010年,金黄色葡萄球菌中耐甲氧西林株总检出率为85.07％(678/797),凝固酶阴性葡萄球菌中耐甲氧西林株总检出率为73.17％(150/205);大肠埃希菌和肺炎克雷伯菌产超广谱β 内酰胺酶株的总检出率分别为64.19％（561/874）、46.31％（301/650）。金黄色葡萄球菌对万古霉素、替考拉宁敏感,对复方磺胺甲口恶唑敏感率（68.42％～74.51%）较高,对其余抗菌药物敏感率均＜30%;凝固酶阴性葡萄球菌对万古霉素、替考拉宁敏感;大肠埃希菌和肺炎克雷伯菌对亚胺培南和美罗培南敏感率（95.52％～100.00％）最高,大肠埃希菌对第三代头孢菌素头孢噻肟、头孢曲松、头孢哌酮和氟喹诺酮类环丙沙星、左氧氟沙星敏感率均＜30％。3年铜绿假单胞菌对头孢他啶和美罗培南的敏感率均较高,分别为60.31%~85.83%、59.38%~73.23%。结论该院分离的主要病原菌对常用抗菌药物耐药性普遍较高,应加强监控,合理使用抗菌药物,有效预防和控制医院感染的发生。     

不同标本来源分离的大肠埃希菌耐药性分析

目的了解临床不同标本分离的大肠埃希菌的耐药特点及差异,以合理使用抗菌药物。方法收集2005年1月-2006年12月分离自中段尿,痰分泌物标本的大肠埃希菌,采用天地人微生物分析系统及相配套的药敏试验卡进行细菌鉴定及药敏测定,并统计比较不同标本所检出大肠埃希菌对抗菌药物的耐药率。结果共检出大肠埃希菌285株,其中中段尿检出150株,痰64株,分泌物71株。中段尿与痰分离的大肠埃希菌对复方新诺明、庆大霉素、阿莫西林/克拉维酸的耐药率差异均有显著性;中段尿与分泌物分离大肠埃希菌对复方新诺明、头孢他啶、妥布霉素、阿莫西林/克拉维酸的耐药率差异均有显著性;痰与分泌物分离的大肠埃希菌对头孢他啶、环丙沙星、阿莫西林/克拉维酸的耐药率差异有显著性。结论不同标本分离的大肠埃希菌对同一抗菌药物耐药率不同,治疗不同部位大肠埃希菌引起的感染,要考虑由于感染部位不同而产生的耐药性以及药物有效浓度的差异,按照药敏结果合理、有效使用抗菌药物。     

哌拉西林/他唑巴坦对血流感染肠杆菌科细菌体外抗菌活性研究

目的 调查血液中肠杆菌科细菌对哌拉西林/他唑巴坦的耐药率变化,了解哌拉西林/他唑巴坦对肠杆菌科细菌的耐药情况.方法 收集2003年1月-2008年12月从医院患者血液标本中分离的肠杆菌科细菌.使用VITEK-32全自动微生物分析仪进行菌种的鉴定,采用K-B法对哌拉西林/他唑巴坦进行药敏试验,对结果进行回顾性调查.结果 自血液中分离到肠杆菌科细菌344株,大肠埃希菌175株(50.9%),肺炎克雷伯菌120株(34.9%),阴沟肠杆菌39株(11.3%),奇异变形菌10株(2.9%),肠杆菌科细菌对哌拉西林/他唑巴坦耐药率为15.1%,其中大肠埃希菌、肺炎克雷伯菌、阴沟肠杆菌对哌拉西林/他唑巴坦耐药率分别为16.0%、16.7%和10.3%,奇异变形菌全部敏感;大肠埃希菌和肺炎克雷伯菌对哌拉西林/他唑巴坦的耐药率从2005年的9.1%和8.0%上升至2008年的22.7%和21.6%;阴沟肠杆菌耐药率无明显变化.结论 血液中检出肠杆菌科细菌以大肠埃希菌和肺炎克雷伯菌为主,哌拉西林/他唑巴坦对肠杆菌科细菌具有强大的抗菌活性,但是大肠埃希菌和肺炎克雷伯菌对哌拉西林/他唑巴坦的耐药率呈上升趋势.     

Escherichia coli O104 Associated with Human Diarrhea, South Africa, 2004-2011

To determine the origin of >4,000 suspected diarrheagenic Escherichia coli strains isolated during 2004-2011 in South Africa, we identified 7 isolates as serotype O104; 5 as enteroaggregative E. coli O104:H4, and 2 as enteropathogenic E. coli O104:non-H4. Pulsed-field gel electrophoresis showed that these isolates were unrelated to the 2011 E. coli O104:H4 outbreak strain from Germany.     

Antimicrobial resistance and class 1 integrons in pathogenic Escherichia coli from dairy farms

The goal of this study was to assess the prevalence of antimicrobial resistance and class 1 integrons, including integron-associated genes, in 24 Escherichia coli isolates from dairy farms. Escherichia coli isolates (n = 14) from dairy cows with mastitis (ECDM), Shiga toxin-producing (STEC) O157:H7 from cull dairy cow fecal samples (n = 9) and bulk tank milk (n = 1) were evaluated for sensitivity to 19 antimicrobial agents used commonly in human and/or veterinary medicine. Multiplex PCR was used to determine presence of genes associated with class 1 integrons (intI1, qacEDelta1, and sulI1). Class 1 integrons were found only in eight of 10 isolates (one STEC O157:H7 and seven ECDM) that demonstrated antimicrobial resistance, and seven of these were resistant to two or more antimicrobial agents. Eight of 10 STEC O157:H7 and six of 14 ECDM were susceptible to all commonly used antibiotics. Five ECDM demonstrated multiple resistances to four or more antibiotics. Most of the 24 isolates examined exhibited resistance against sulfamethoxazole, followed by streptomycin and tetracycline. STEC O157:H7 strains had less prevalence of antibiotic resistance and integron carriage than ECDM. The multiplex PCR method developed for detection of intI1, qacEDelta1, and sulI1 can be used routinely for monitoring presence of these genes. Class 1 integrons were found in eight of 10 E. coli strains that demonstrated antimicrobial resistance; seven of these were resistant to two or more antibiotics. It appears that integrons played a role in the incidence of antimicrobial resistance of the strains used in this study.     

Antimicrobial susceptibility testing of Shiga toxin-producing Escherichia coli from various samples by using a spiral gradient endpoint technique

Shiga toxin-producing Escherichia coli (STEC) remains a major public health concern. Microbial resistance may be due to use of antimicrobial agents (AAs) as a growth promoter in food animals or overuse of AAs in humans. The objective of the current study was to determine the antimicrobial susceptibility patterns of STEC strains isolated from food, veterinary, and clinical sources against 14 AAs by using the spiral gradient endpoint method. One hundred ten isolates from three sources were characterized. Results of the current study showed that all strains were resistant to the folate pathway inhibiting AAs including tylosin tartrate (gradient minimum inhibitory concentration [GMIC] ranges from ≥180.00 to 256.00?μg/mL; end concentration [EC] ranges from ≥130.00 to 151.22 μg/mL; and tail-end concentration [TEC] ≥145.00 μg/mL). All the strains isolated from three sources were susceptible to the fluoroquinolone class of AAs (GMIC ranges from ≤1.00 to 64.30 μg/mL; EC ranges from ≤3.33 to 72.00 μg/mL; and TEC ranges from ≤12.13 to 45.00 μg/mL). Among the food isolates, less resistance was found within the aminoglycoside and amphenicol group (GMIC ≥256.00 μg/mL; EC=161.00 μg/mL). Eight strains were resistant to one to three, 44 strains were resistant to four to six, and two strains were resistant to seven or more AAs. All the clinical isolates (100%) were susceptible to the fluoroquinolones and gentamycin. Results also showed that antimicrobial resistance was observed between four and six AAs among the isolates. Some veterinary isolates were resistant to five AAs. Least AAs resistance was shown by 3.7% of isolates to gentamycin and 7.45% to chloramphenicol. This study showed an increasing trend of antimicrobial resistant strains of STEC, and we suggest that periodic surveillance of the antimicrobial susceptibility may be a useful measure to detect the antimicrobial resistant pathogens.     

Antimicrobial resistance among Salmonella isolates from hospitals in Rome.

The susceptibility to antimicrobial agents of 569 salmonella isolated collected in 1977-8 from patients in hospitals in Rome was tested. Fifty-nine per cent of all isolates were resistant to one or more antimicrobials. Resistance was most common to sulphathiazole, tetracycline, streptomycin, whereas colistin, gentamicin, tobramycin, trimethoprim-sulphamethoxazole and nalidixic acid were the most active in vitro. Multiple resistance was most frequently found in strains of Salmonella wien and S. typhimurium (94% and 38% respectively). A significant change in the resistance pattern of S. wien was observed between 1977 and 1978, with a significant increase of susceptibility to some antimicrobials in 1978. Twenty-one R-plasmids transmissible to E. coli K12 were derived from 46 resistant strains of S. typhimurum.     

Increasing antibiotic resistance among isolates of Escherichia coli recovered from inpatients and outpatients in a Saudi Arabian hospital.

OBJECTIVE: To study the pattern of antibiotic resistance among Escherichia coli and the trend in resistance during a 6-year period in a Saudi Arabian hospital. DESIGN: Retrospective in vitro surveillance study of the antibiotic susceptibility pattern among E. coli isolates recovered from outpatients and from inpatients. SETTING: A general hospital in Saudi Arabia. PATIENTS: All patients with a culture positive for E. coli during a 6-year study period. RESULTS: A statistically significant increase in antibiotic resistance was observed among outpatient and inpatient isolates of E. coli. Inpatient isolates were more likely to be resistant to antimicrobial agents. Among isolates from outpatients, 50% were resistant to ampicillin, 33% were resistant to trimethoprim-sulfamethoxazole (TMP-SMZ), and 14% were resistant to ciprofloxacin. Among isolates from inpatients, 63% were resistant to ampicillin, 44% were resistant to TMP-SMZ, and 33% were resistant to ciprofloxacin. There was a low rate of resistance to imipenem (0.3% of isolates), amikacin (2%), and nitrofurantoin (2.4%-6.5%). Resistance to ceftazidime was detected in 9% of outpatient isolates and 17% of inpatient isolates. Multidrug resistance was defined as resistance to 2 or more classes of antibiotics. Multidrug resistance was detected in 2.0%-28.1% of outpatient isolates and 7.4%-39.6% of inpatient isolates, depending on the combination of antimicrobials tested. More isolates were resistant to ampicillin plus TMP-SMZ than to any other combination of antimicrobials. CONCLUSION: The prevalence of antibiotic resistance among outpatient and inpatient E. coli isolates increased during the study period. The rates of antibiotic resistance were statistically significantly higher among inpatient isolates, compared with outpatient isolates. These findings call for wiser use of antibiotics and continued surveillance of antibiotic resistance.