Prevalence and Study of the Clonality of Extended-Spectrum Beta-Lactamase-Producing Klebsiella pneumoniae Strains in Neonatology at the University Hospitals of Abidjan by the Pulsed Field Gel Electrophoresis and the Quantitative Antibiogram

Background: ESBL-producing strains of Klebsiella pneumoniae, one of the main causes of nosocomial and hospital-acquired infections, are commonly associated with therapeutic impasses. Surveillance of these multidrug-resistant pathogens is a crucial tool for controlling and preventing infections. This surveillance involves the use of appropriate molecular and phenotypic typing techniques. The choice of techniques is based on criteria such as discriminatory power, intra- and inter-laboratory reproducibility, epidemiological concordance, ease of use and cost. The aim of our study was to identify clusters of Extended-Spectrum Beta-Lactamase-producing Klebsiella pneumoniae (ESBL-K. pneumoniae) strains circulating in neonatology using quantitative antibiogram (QA) and Pulsed Field Gel Electrophoresis (PFGE). Materials and Methods: This cross-sectional study included 55 K. pneumoniae strains isolated from a total of 513 samples. These various samples are taken from newborns, healthcare personnel, and the environment. K. pneumoniae identification followed standard bacteriological procedures and was confirmed using the Vitek® 2 (bioMérieux). The detection of the ESBL phenotype was performed using the synergy test. QA and PFGE were used to identify clonal relationships between the various strains isolated. Concordance between these two methods was assessed by calculating Cohen’s KAPPA coefficient and Simpson’s diversity index. Results: Among the 55 K. pneumoniae strains included in this study, 58.2% (32/55) were found to be Extended-Spectrum Beta-Lactamase (ESBL) producers. Most of these strains were isolated from neonatal samples (blood samples and rectal swabs). The quantitative antibiogram method applied to 28 out of the 32 ESBL-producing strains revealed that the isolates were grouped into 5 clusters. Pulsed Field Gel Electrophoresis performed on a total of 16 ESBL-producing strains showed the existence of four profiles. A perfect concordance was observed between the two methods. Conclusion: The results of this study highlighted the existence of clonal strains of various origins within neonatology units.

Establishment and Comparison of Pulsed-field Gel Electrophoresis,Multiple-locus Variable Number Tandem Repeat Analysis and Automated Ribotyping Methods for Subtyping of Citrobacter Strains

Objective To establish and compare the pulsed-field gel electrophoresis （PFGE）, multiple-locus variable number tandem repeat analysis （MLVA） and automated ribotyping for subtyping of Citrobacter strains. Methods PFGE protocol was optimized in terms of plug preparation procedure, restriction enzymes and configuration of electrophoretic parameters. MLVA method was evaluated by finding variable number tandem repeats in two genomes of Citrobacter strains. The ribotyping was performed by using the automated RiboPrinter system. Results We optimized the plug preparation procedure, focused on the cell suspension concentration （turbidity of 2.5 to 3.5）, SDS addition （no SDS needed） and lysis time （1 h）, and selected the appropriate restriction enzyme （Xbal） and the electrophoretic parameters （1.0 s-20.0 s for 19 h） of PFGE. There was nearly no discriminatory power of MLVA between Citrobacter strains. For 51 Citrobacter strains, automated ribotyping gave a D-value of 0.9945, while PFGE gave a D-value of 0.9969. Both PFGE and automated ribotyping clustered strains from the same sources （with the same species from the same place at the same time identified as the same source） and divided strains from different sources （from different years, places and hosts） into different subtypes. Conclusion PFGE protocol established in this paper and automated ribotyping are suitable for application in Citrobacter subtyping.

Optimization of Pulse-Field Gel Electrophoresis for Borrelia burgdorferi Subtyping

Objective To optimize the performance of Pulsed-Field Gel Electrophoresis （PFGE） for the comparison of inter-laboratory results and information exchange of Borrelia burgdorferi subtypingo Methods A panel of 34 strains of B. burgdorferi were used to optimize PFGE for subtyping. In order to optimize the electrophoretic parameters （EPs）, all 34 strains of B. burgdorferi were analyzed using four EPs, yielding different Simpson diversity index （D） values and the epidemiological concordance was also evaluated. Results The EP of a switch time of l s to 25 s for13 h and l s to10 s for 6 h produced the highest D value and was declared to be optimal for Mlul and 5mal PFGE of B. burgdorferi. Mlul and Smal were selected as the first and second restriction enzymes for PFGE subtyping of B. burgdorferi according to discrimination and consistency with epidemiological data. Conclusion PFGE can be used as a valuable test for routine genospecies identification of B burgdorferi.

CHARACTERIZATION OF PATHOGENIC FUNGI GENOMES USING PULSED FIELD GEL ELECTROPHORESIS

Pulsed field gel electrophoresis(PFGE) has been firstly introduced in characterization of the pathogenic fungi Penicillium marne f fei and Exophiala dermatitidis genomes.The numbers and sizes of their chromosomes have been detected.Polymorphism was identified on the smallest chromosome of E.dermatitidis.The result shows that PFGE for characterization of large molecular DNA pathogenic fungi is very suitable,it is more simple and more efficacy.The result also shows the diversity of pathogenic fungi is relative common even in rare occurred pathogenic fungi such as E.dermatitidis.

Antimicrobial resistance, genotypic characterization and pulsed-field gel electrophoresis typing of extended spectrum β-lactamases-producing clinical Escherichia coli strains in Macao, China

Background The rise of the production of CTX-M class extended spectrum β-lactamases （ESBLs） has been well documented in traveling countries but no data are found for Macao, an international travel city. The objectives of this study were to identify the antimicrobial resistance pattern, and determine the prevalence, genotype and clonal relationship of ESBLs in 209 clinical Escherichia coli strains from Macao, China. Methods Antimicrobial susceptibility test was performed to determine the resistance patterns of the isolates using the disk diffusion method with 17 antimicrobial agents. Phenotypic detection was screened and confirmed according to the Clinical and Laboratory Standards Institute. Genotypic characterization was detected by isoelectric focusing analysis, polymerase chain reaction and sequencing. The clonal relationship between the different ESBL isolates was studied by pulsed-field gel electrophoresis （PFGE）. Results Imipenem and meropenem exhibited 100% susceptible among 209 strains. Overall, 82.3%, 67.3%, 52.9%, 51.2% and 51.0% of the isolates displayed resistance to ampicillin, tetracylcline, ciprofloxacin, sulfamethoxazole trimethoprin and gentamycin. The prevalence rate of ESBLs was 30.1%. Antibiotic resistances were found to be significantly higher among the ESBL producing group compared to non-ESBL producing group. We detected CTX-M-14 to be the major genotypic characterization of ESBLs （76.2%）. Two strains showed indistinguishable patterns by PFGE. Conclusions The prevalence of antimicrobial resistance is alarming high in Macao. Antimicrobial resistance is significantly higher among the ESBL producing group. This study documented CTX-M-14 as the predominant ESBL type. Although indistinguishable pattern was found between two strains, it was too small to decide whether any of the investigated strains was epidemic. Our findings may be also pertinent for other geographic areas undergoing similar travel characteristics to understand the corresponding effects on bacterial populations.

副溶血性弧菌引起食源性疾病暴发事件调查与病原特征分析

目的调查和分析山西省阳泉市一起食源性疾病暴发事件中副溶血性弧菌的病原特征,提高对食物中毒应急事件的处理能力。方法使用脉冲场凝胶电泳(PFGE)、血清学分型、毒力基因检测、药物敏感实验和全基因组测序的方法分析25例有腹泻、腹痛、恶心、呕吐等消化道症状的患者分离出的11株分离菌株。结果11株分离菌株均为副溶血性弧菌,其中8株副溶血性弧菌分离株携带毒力基因tdh,1株同时携带毒力基因trh和tdh,1株只携带毒力基因trh,1株只有毒力基因tlh。血清型分为3种型别,分别是O10:K4、O4:K63以及O5:unknown。根据11株副溶血性弧菌的PFGE图谱将菌株分为5种不同的群,基于全基因组序列的分析显示8株来自患者的副溶血性弧菌具有相同的ST型,属于同一克隆群。副溶血性弧菌病原体毒力、耐药基因和药敏表型相同,符合暴发流行病学特征,判断其为该起食物中毒事件的病原体。11株菌均只含有blaCARB耐药基因,且未检测到耐药质粒,对氯霉素、萘啶酸、四环素、美罗培南、阿米卡星、氨苄西林、厄他培南、替加环素、头孢噻肟、头孢他啶和环丙沙星均敏感,对多黏菌素E中度敏感,均无耐药表型。结论这是一起由多种血清型副溶血性弧菌污染了食品而导致的食源性疾病暴发事件。该食堂储存食物时生熟不分,副溶血性弧菌机会性繁殖在合适的含盐食物中也可以增殖,进而引起该起事件发生。

1起ST19型鼠伤寒沙门氏菌引起的食物中毒调查、溯源分析与探讨

目的分析武汉市某区1起食物中毒事件的致病原因,探讨分离菌株之间的分子流行病学关系,为食源性疾病暴发溯源和临床诊治提供参考依据。方法采集食物中毒相关样本20份,提取样本总DNA进行18种食源性致病菌多重PCR检测,同时按时GB4789.4-2016进行病原菌分离鉴定;应用传统玻片凝集法和微量肉汤稀释法对阳性菌株进行血清型分型和耐药性检测,并提取所有菌株核酸进行全基因组测序组装,利用Abricate和SeqSero在线预测每株菌的血清型和耐药基因,然后与传统方法进行比较分析。对分离的9株沙门氏菌分别采用脉冲场凝胶电泳(PFGE)和全基因组序列方法(WGS)递进分析。结果共检出12株沙门氏菌(菌株编号DXH001~DXH012),其中病例肛拭子样本7份、病例粪便样本2份,工作人员肛拭子样本3份。常规血清型分型均为B群鼠伤寒沙门氏菌,与全基因组测序鉴定分型结果一致。12株菌株耐药谱完全一致,对阿米卡星、氨苄西林、头孢唑啉、庆大霉素、哌拉西林、四环素均耐药。基于全基因组预测的氨基糖苷类、头孢菌素、青霉烷、四环素的耐药性与耐药表型结果完全一致。选取DXH001~DXH009开展PFGE和WGS分析。9株鼠伤寒沙门氏菌获得完全一致的PFGE图谱,全基因组序列大小无明显差异,约为4.9 Mbp,MLST型均为ST19。从SNP的最小生成树来看共存在17个变异位点,各菌株间SNP差异数为1~6。全基因组系统发育进化树分析显示,9株沙门氏菌自成一簇,与数据库其他沙门氏菌相差甚远,属于新的克隆分支。同源性最高的来源于江西的GCF_020221795.1参考样本。结论本次食物中毒事件致病源为鼠伤寒沙门氏菌ST19,为同一暴发来源。9株沙门氏菌遗传距离较近,但与数据库中其他沙门氏菌遗传距离较远,自成一簇属于新的克隆分支。本研究中沙门氏菌具有多重耐药性,需加强对多重耐多药菌株的监控及抗菌药物使用的监管。

云南省2016—2022年志贺氏菌分子分型及耐药性分析

目的对云南省2016—2022年食源性疾病主动监测分离的志贺氏菌进行血清、分子分型和药敏试验等分析,了解云南省志贺氏菌的病原学特性,为志贺氏菌感染的防控和治疗提供数据支持。方法2016年1月至2022年12月从患者粪便中分离志贺氏菌,采用玻片凝集法进行血清学分型,脉冲场凝胶电泳(PFGE)进行分子分型分析,微量肉汤稀释法进行药敏试验。结果共分离志贺氏菌89株,其中福氏志贺氏菌占52.81%,宋内志贺氏菌占47.19%。PFGE分析发现,2种志贺氏菌均分为A和B 2个聚类簇,B簇为优势簇。47株福氏志贺氏菌分为30种PFGE带型,有3组优势带型,42株宋内志贺氏菌分为22种PFGE带型,有4组优势带型,并识别两起疑似暴发事件。志贺氏菌对13种抗生素存在不同程度的耐药,78.65%的菌株为多重耐药菌株。结论云南省志贺氏菌PFGE优势带型明显,部分带型聚集分布。耐药形势严峻,多重耐药现象严重。福氏志贺氏菌和宋内志贺氏菌耐药表型存在差异。

2022—2023年贵州省单核细胞增生李斯特氏菌PFGE分型及耐药性分析

目的了解2022—2023年贵州省单核细胞增生李斯特氏菌血清表型、脉冲场凝胶电泳(pulse-field gel electrophoresis,PFGE)分子分型特征和耐药情况,旨在为贵州省李斯特氏菌病的防控提供实验室数据支持并提高预警监测能力。方法收集2022年1月—2023年12月贵州省致病菌识别网中心实验室监测腹泻疾病相关样本1220份,按照GB 4789.30—2016《食品安全国家标准食品卫生微生物学检验单核细胞增生李斯特氏菌检验》的执行标准分别进行分离培养,按照《国家致病菌识别网实验室监测技术手册(2022试用版)》进行实时荧光聚合酶链反应(polymerase chain reaction,PCR)检测方法鉴定,多重PCR检测血清型分型、PFGE分子分型和药敏试验。结果1220份腹泻疾病相关样本分离出424株菌株,其中单核细胞增生李斯特氏菌11株,阳性率为2.59%(11/424);11株单核细胞增生李斯特氏菌分为6种血清表型,血清型分布为1/2a、1/2b、1/2c、3a、3b和3c型;11株单核细胞增生李斯特氏菌对头孢西丁(cefoxitin,FOX)耐药率高达100%,对氯霉素(chloroamphenicol,CHL)中介率为72.72%,剩余12种药物[红霉素(erythromycin,ERY)、复方新诺明(trime-thoprim/sulfamethoxazole,T/SUL)、庆大霉素(gentamicin,GEN)、亚胺培南(imipenem,IPM)、苯唑西林(benzoxacillin,OXA)、克林霉素(clindamycin,CLI)、环丙沙星(ciprofloxacine,CIP)、达托霉素(datomycin,DAP)、氨苄西林(ampicillin,AMP)、四环素(tetracycline,TET)、万古霉素(vancomycin,VAN)、青霉素(chloramphenical,PEN)]均100%敏感;经AscⅠ酶切后11株单核细胞增生李斯特氏菌分成7种PFGE带型,相似性为40%~100%,其中3株菌相似性高达100%。结论2022—2023年贵州省发生了一起家庭聚集性李斯特氏菌病事件,遵义市肉制品中存在相同的污染来源,且污染源持续存在,贵州省具有多种致病性单核细胞增生李斯特氏菌,但尚未出现严重耐药情况。

一起由副溶血性弧菌引起的食物中毒事件的病原检测及溯源分析

目的:对一起农村自办婚宴发生的食物中毒事件进行病原检测及溯源分析。方法:对采集的粪便、肛拭子、手涂抹样等样本进行病原学检测,对检出的副溶血性弧菌进行血清凝集、3种毒力基因检测、MIC药敏试验和PFGE分型。结果:该起食物中毒事件共涉及10例病例,发病时间较集中,首末病例发病时间间隔4.75 h,患者主要症状为腹痛、腹泻、恶心、呕吐等。采集的样本中共检出5株副溶血性弧菌,分为3种血清型,4种PFGE型,毒力基因均为tlh+tdh+trh-,对头孢唑啉全部耐药。结论:该起农村自办婚宴食物中毒事件由副溶血性弧菌感染引起。

院内多重耐药鲍曼不动杆菌分子流行病学和耐药性研究

目的分析院内临床和环境多重耐药鲍曼不动杆菌(MDRAB)的耐药机制和分子流行病学特征,为预防和控制MDRAB的传播提供依据。方法收集2020年5月至2021年4月院内临床及环境分离到的非重复MDRAB菌株34株,其中临床标本25株,环境标本9株。应用PCR和测序方法检测MDRAB的耐药基因。多位点序列分型(MLST)和脉冲场凝胶电泳(PFGE)对MDRAB进行分子分型。结果34株MDRAB阳性基因携带率分别为:blaOXA23、blaOXA-51及blaOXA64gp均为100%,TEM 85.3%(29/34)。25株临床MDRAB监测到7个ST序列类型:分别为ST540(10/25)、ST195(5/25)、ST369(3/25)、ST208(2/25)、ST381(2/25)、ST938(2/25)和ST451(1/25);6个克隆群:分别为A群(9/25)、D群(8/25)、C群(4/25)、F群(2/25)、E群(1/25)、G群(1/25)。9株环境MDRAB监测到2个ST序列类型:ST208(8/9)、ST540(1/9);2个克隆群:B群(8/9)、C群(1/9)。结论院内MDRAB主要来源于重症监护病房,blaOXA-51-Like+blaOXA-23+blaTEM-like是主要碳青霉烯耐药模式。院内临床流行的主要序列类型为ST540和ST195,主要的克隆群为A群、D群。ST540、A克隆群MDRAB贯穿整个研究阶段且在多个重症监护病区播散流行。临床与环境MDRAB主要流行的ST序列型和克隆群存在差异。

遵义市食源性沙门菌分子分型及耐药研究

目的了解遵义市食源性沙门菌分型及耐药特征。方法收集遵义市2020-2022年食源性沙门菌,采用玻片凝集法对沙门菌进行血清分型,利用脉冲场凝胶电泳(PFGE)对沙门菌进行分子分型,采用肉汤稀释法对沙门菌进行耐药监测,应用BioNumerics软件进行数据分析。结果收集的21株沙门菌分为16种血清型,其中肯塔基沙门菌3株、德尔卑沙门菌2株、肠炎沙门菌2株、希林登沙门菌2株,其余均为1株。PFGE结果显示带型呈现多态性,同源性最高为62.96%。药敏试验结果显示食源性沙门菌对氨苄西林耐药率最高,为71.43%,其次对四环素耐药率达61.90%,多重耐药率为76.19%。结论遵义市食源性沙门菌血清型和遗传性多样,对抗菌药物的耐药率高,多重耐药严重。

潮州市临床沙门氏菌的耐药性和分子分型

为了研究引起潮州市临床患者腹泻沙门氏菌的血清型分布、耐药谱和分子分型特征,对2021年分离自广东省潮州市的定点监测医院腹泻患者的55株沙门氏菌,采用血清凝集法鉴定血清型、微量肉汤稀释法检测对17种抗生素的敏感性,脉冲场凝胶电泳对菌株进行分子分型.结果显示,在55株沙门氏菌中,主要的血清型为鼠伤寒沙门氏菌,占41.82%;其次是胥莱士亥姆沙门氏菌和瓦根尼亚沙门氏菌,均占10.91%.药物敏感性试验表明,菌株对氨苄西林/舒巴坦的耐药率最高,达80.00%;其次是四环素、氯霉素和复方新诺明,分别为76.36%、50.91%和49.09%.在55株沙门氏菌中,48株沙门氏菌经XbaⅠ内切酶处理后获得分子分型结果.它们共产生47个PFGE带型,呈现高度多态性,没有明显的优势PFGE带型.该研究结果提示引起腹泻的沙门氏菌血清型以鼠伤寒沙门氏菌为主.PAGE分子分型散在分布,表明潮州市沙门氏菌总体呈散发多态性,没有形成大规模的流行.值得关注的是,对抗生素耐药性及多重耐药性严重,应当引起重视并持续开展耐药及病原学监测.

丰城市食源性沙门氏菌的血清型、耐药性及同源性分析

目的探究丰城市食源性沙门氏菌的血清型分布特征、耐药性分析及脉冲场凝胶电泳(PFGE)分子溯源分析,为食源性疾病的暴发预警提供科学依据。方法对丰城市2015年4月至2022年11月分离来自食品和腹泻患者的沙门氏菌进行血清学分型以及耐药性分析,应用PFGE分析菌株之间的同源关系。结果在756份食品和806份腹泻患者样品中,共检出沙门氏菌49株,其中鼠伤寒沙门氏菌占比率为38.78%,其次肠炎沙门氏菌占比率为32.65%。选取的35株沙门氏菌对氨苄西林耐药率最高,耐药率达到82.86%,其次是对头孢唑啉和萘啶酸耐药率达到48.57%,其中30株具有多重耐药性(30/35,85.71%)。49株沙门氏菌DNA指纹图谱同源性为55.4%~100.0%。结论丰城市从食源性分离到的沙门氏菌株主要以鼠伤寒沙门氏菌和肠炎沙门氏菌为主,耐药和多重耐药存在严重,应加强对抗生素规范使用,DNA指纹图谱显示沙门氏菌较高同源性,需加强PFGE的日常监测为沙门氏菌的食品安全风险提供预警。

移动性多黏菌素耐药基因介导的大肠埃希菌药敏特点与同源性分析

目的分析多黏菌素耐药大肠埃希菌的耐药机制、药敏特点及其同源性,为有效预防和控制其暴发及流行提供分子流行病学依据。方法收集2016年5月至2022年6月分离自临床的多黏菌素耐药大肠埃希菌,应用PCR技术筛选移动性多黏菌素耐药基因(mobile colistin resistance,MCR),采用微量肉汤稀释法测定最小抑菌浓度。收集患者的临床资料,利用脉冲场电泳技术(PFGE)对收集到的菌株进行同源性分析并对其中1株进行全基因组测序分析。结果分离并鉴定出4株携带有MCR-1基因的多黏菌素耐药大肠埃希菌,4株菌株除了对替加环素均敏感外,对于临床常见的绝大多数抗生素均表现出不同程度的耐药。临床资料分析均未发现患者有多黏菌素使用史。该4株菌可分为2种类型,其中A型3株,B型1株。对其中1株菌进行全基因组测序分析发现MCR-1基因位于约70 kb的质粒上。结论携带MCR-1基因的多黏菌素耐药大肠埃希菌具有克隆传播的潜在威胁,对临床常见抗生素均表现出较高的耐药性,为临床治疗带来极为严重的挑战,需要加强防护措施,防止其暴发流行。

一起肠炎沙门氏菌感染的食源性疾病暴发事件的溯源分析及药敏检测

目的对一起因食用肠炎沙门氏菌污染的熏肉大饼引起的食源性疾病暴发事件进行溯源分析。方法对8例患者进行流行病学调查,采集相关环境、食品及粪便等样本,根据国家标准进行实验室检测,经增菌后挑取可疑菌落进行生化鉴定,对检出的6株沙门氏菌株采用标准诊断血清进行血清凝集试验,药敏试验及脉冲场凝胶电泳。结果该起事件发病8例,6份样本中,分离出肠炎沙门氏菌,沙门氏菌检出率食品、环境和病人粪便样本均为100%,药敏试验结果显示,耐药谱为多粘菌素E(Colistin,CT)―头孢噻肟(Cefotaxime,CTX)―四环素(Tetracycline,TET)―环丙沙星(Ciprofloxacin,CIP)―氨苄西林(Ampicillin,AMP)―氨苄西林/舒巴坦(Ampicillin/Sulbactam,AMS),均呈现6重耐药现象,对氯霉素(Chloramphenicol,CHL)、复方新诺明(Sulfamethoxazole,SXT)、厄他培南(Ertapenem,ETP)、美罗培南(Meropenem,MEM)、头孢他啶(Ceftazidime,CAZ)、头孢他啶/阿维巴坦(Ceftazidime/avibactam,CZA)、替加环素(Tigecycline,TIG)、阿奇霉素(Azithromycin,AZM)、阿米卡星(Amikacin,AMI)敏感,6株菌的脉冲场凝胶电泳(Pulse Field Gel Electrophoresis,PFGE)条带一致,同源性100%,显示为同一克隆。结论该起事件为市民食用被肠炎沙门氏菌污染的熏肉大饼引起的食源性疾病暴发事件。

Molecular Characteristics of Neisseria meningitidis Isolated during an Outbreak in a Jail: Association with the Spread and Distribution of ST-4821 Complex Serogroup C Clone in China

Objective To characterize the meningococcal strains isolated from cases and close contacts with meningococcal disease associated with an outbreak in a jail in May 2010 by investigating the national distribution of hyperinvasive ST-4821 serogroup C clone associated with this outbreak. Methods The cases were described based on the clinical symptoms and laboratory results. Pharyngeal swabs were cultured for N. meningitidis from men in the jail. Meningococcal isolates were identified by serogrouping, pulsed-field gel electrophoresis （PFGE） and multilocus sequence typing （MLST）, respectively. Four hundred and sixteen serogroup C N. meningitidis strains were collected from 27 provinces between 2003 and 2010 for a nationwide survey and analyzed by PFGE and MLST. Results Three persons in a jail system were infected with invasive N. meningitidis serogroup C. All isolates tested had matching PFGE patterns and belonged to the multilocus sequence type （ST） 4821 clonal complex. All 47 N. meningitidis strains were identified from the pharyngeal swabs of 166 peoples in the jail, and 26 of them belonged to ST-4821 serogroup C clone, and 90.14% （375/416） serogroup C strains identified in the nationwide survey belonged to the ST-4821 complex. The ST-4821 serogroup C clone was spread nationwide, distributed in 24 provinces, especially in eastern provinces between 2003 and 2010. Conclusion Endemic transmission and carriage rate of ST-4821 serogroup C clone are high in this jail system. The ST-4821 serogroup C clone is spreading in China and nationwide distributed despite the existence of some effective vaccines.

综合医院ICU患者及环境分离多重耐药菌耐药率及同源性

目的调查某院重症监护病房(ICU)患者及环境分离多重耐药菌(MDRO)同源性,为临床预防控制MDRO感染提供依据。方法收集2021年11月17日—12月17日某三级甲等综合医院重症监护病房(ICU)患者及环境分离的MDRO,对分离株进行药敏分析以及脉冲场凝胶电泳(PFGE)试验及聚类分析。结果共收集22株MDRO[耐碳青霉烯类肺炎克雷伯菌(CRKP)6株,多重耐药鲍曼不动杆菌(MDR-AB)11株,耐甲氧西林金黄色葡萄球菌(MRSA)5株],其中临床患者来源菌株11株,环境来源菌株11株,部分环境株与临床株高度同源。ICU环境,包括工作人员生活区域物体表面、微波炉按键和开关等均检出MDRO。患者床旁桌和水池消毒处理后仍被检出CRKP、MDR-AB,护理员洗手后手检出与患者使用的听诊器完全同源的MRSA。CRKP对常用抗菌药物均耐药(头孢他啶/阿维巴坦除外);MDR-AB临床株对米诺环素耐药率为40.0%,对其他抗菌药物耐药率均≥60%,MDR-AB环境株耐药率较临床株低。结论ICU MDRO临床株与环境株高度同源,存在MDRO通过医院环境在医院传播和交叉感染的可能。应加强环境清洁消毒措施的落实,提高手卫生依从性,切断病原菌医院传播途径,减少MDRO医院感染的发生。

89株蜡样芽孢杆菌食品分离株携带毒力基因情况及PFGE分型研究

目的了解上海市青浦区食品中蜡样芽孢杆菌污染情况、蜡样芽孢杆菌毒力基因的携带情况及脉冲场凝胶电泳(PFGE)分型。方法参照GB4789.14-2014对729份食品样品(包含熟制米面制品、熟肉制品、学生午餐、酱料、蔬菜)进行蜡样芽孢杆菌的分离鉴定、生化分型;应用PCR对检出的蜡样芽孢杆菌进行9种腹泻毒素毒力基因和1种呕吐毒素毒力基因检测;使用PFGE分型方法及BioNumerics5.10软件进行聚类分析。结果该研究729份食品样品中检出89株蜡样芽孢杆菌,检出率为12.21%,其中熟制米面制品中蜡样芽孢杆菌检出数最多、检出率最高(35株,16.83%),生化分型以2型为主。9株菌株携带所有腹泻毒素毒力基因,14株携带呕吐毒素基因ces。PFGE结果显示,89株菌株可分为85个带型,NotⅠ酶切可得5~12条DNA片段,存在带型完全一致菌株。结论上海市青浦区熟制米面制品、熟肉制品、学生午餐等食品中均能检出蜡样芽孢杆菌且毒力基因携带率较高,存在同地点采样不同样品受相同菌株污染的情况,需加强食品的常规监测,预防食品受污染后引起的食源性疾病,保障公众食品安全,排除潜在食源性风险。

2015-2021年西安市腹泻患者沙门菌耐药性及分子分型研究

目的 分析2015-2021年西安市腹泻患者沙门菌分离株的血清型分布、耐药情况及分子分型特征,为沙门菌引起腹泻的防治提供科学依据。方法 对分离自2015-2021年西安市感染性腹泻病例的128株沙门菌进行血清学分型,采用微量肉汤稀释法和脉冲场凝胶电泳(PFGE)进行菌株的药物敏感性测定和分子分型分析。结果 128株沙门菌分为23种血清型,优势血清型为沙门菌4,[5],12:i:-、肠炎沙门菌和鼠伤寒沙门菌,占比分别为34.38%、21.88%和17.19%。111株菌(86.72%)对至少1种抗生素耐药,对氨苄西林耐药率最高为78.91%,其次为四环素(69.50%)、链霉素(67.19%)和萘啶酸(53.12%)。共检出41种耐药谱,菌株的耐药谱相对分散,最常见耐药谱为氨苄西林-四环素-链霉素。多重耐药率高达76.56%,沙门菌4,[5],12:i:-和鼠伤寒沙门菌多重耐药现象严重。PFGE聚类分析得到94种带型,相似度为56.8%~100.0%,共聚集形成13个簇。相同血清型菌株PFGE带型相似度较高,同一血清型带型相同或成簇的菌株耐药谱有较高的一致性。结论 西安市腹泻患者沙门菌血清型以4,[5],12:i:-、肠炎沙门菌和鼠伤寒沙门菌为主,菌株的耐药及多重耐药现象严重,需加强本地区沙门菌耐药性监测。