耐甲氧西林金黄色葡萄球菌同源性分析及耐药性研究

目的对临床分离的耐甲氧西林金黄色葡萄球菌(MRSA)进行耐药情况和分子流行病学监测,探讨院内MRSA的流行趋势。方法收集我院2009年1月~2011年6月临床标本分离的MRSA菌株60株;采用Microscan WalkAway 40进行菌株鉴定,同时对所有金黄色葡萄球菌进行药物敏感性分析;采用脉冲场凝胶电泳技术对耐甲氧西林金黄色葡萄球菌进行分子分型。结果共收集60株MRSA菌株,其中17株被认为是可疑社区获得(CAMRSA),43株被认为是医院获得(HA-MRSA)。所有菌株均对万古霉素、替考拉宁、利奈唑胺、呋喃妥因和奎奴普丁/达福普汀敏感,未出现耐药菌株。CA-MRSA与HA-MRSA对左旋氧氟沙星和利福平的敏感性有明显差异。临床分离的MRSA菌株PFGE分型较为分散,共分为13种型别,每种型别的菌株数分别为2~6株不等,未出现大范围的院内流行克隆。结论本院收集的临床分离的MRSA菌株多重耐药性严重,其中CA-MRSA相对HAMRSA敏感性稍高。所有金黄色葡萄球菌未出现糖肽类抗菌药物耐药。MRSA菌株未出现大范围的院内流行株,但仍应加强院内感染流行控制。     

Genotypic Characterization of Methicillin-resistant Staphylococcus aureus Isolated from Pigs and Retail Foods in China

Objective To investigate the genotypic diversity of Methicillin-resistant Staphylococcus aureus (MRSA) isolated from pigs and retail foods from different geographical areas in China and further to study the routes and rates of transmission of this pathogen from animals to food. Methods Seventy-one MRSA isolates were obtained from pigs and retail foods and then characterized by multi-locus sequencing typing (MLST), spa typing, multiple-locus variable number of tandem repeat analysis (MLVA), pulsed-field gel electrophoresis (PFGE), and antimicrobial susceptibility testing. Results All isolated MRSA exhibited multi-drug resistance (MDR). Greater diversity was found in food-associated MRSA (7 STs, 8 spa types, and 10 MLVA patterns) compared to pig-associated MRSA (3 STs, 1 spa type, and 6 MLVA patterns). PFGE patterns were more diverse for pig-associated MRSA than those of food-associated isolates (40 vs. 11 pulse types). Among the pig-associated isolates, CC9-ST9-t899-MC2236 was the most prevalent clone (96.4%), and CC9-ST9-t437-MC621 (20.0%) was the predominant clone among the food-associated isolates. The CC9-ST9 isolates showed significantly higher antimicrobial resistance than other clones. Interestingly, CC398-ST398-t034 clone was identified from both pig- and food-associated isolates. Of note, some community- and hospital-associated MRSA strains (t030, t172, t1244, and t4549) were also identified as food-associated isolates. Conclusion CC9-ST9-t899-MC2236-MDR was the most predominant clone in pigs, but significant genetic diversity was observed in food-associated MRSA. Our results demonstrate the great need for improved surveillance of MRSA in livestock and food and effective prevention strategies to limit MDR-MRSA infections in China.     

贵阳市甲型副伤寒沙门菌脉冲电场凝胶电泳分型分析

目的了解贵阳市甲型副伤寒沙门菌的分子流行病学特征,分析菌株的相似性,为追踪传染来源、查找传播途径提供线索。方法用脉冲电场凝胶电泳(pulsed field gelelectrophoresis,PFGE)方法进行分型。结果根据细菌染色体DNA的SpeI酶切图谱,将贵阳地区146株甲型副伤寒沙门菌分成10个PFGE带型,1型32株占21.9%,2型73株占50.0%,3型13株占8.9%,4型7株占4.8%,5型14株占9.6%,6型、7型、8型和9型各1株,各占0.7%,10型3株占2.7%,各型之间的相似性在98.1%～72.0%。暴发株24株被分为5个PFGE带型,1型占54.2%,带菌者1株为1型。各年菌株的PFGE带型不尽相同,1型和2型为常年流行带型。高流行区县的甲型副伤寒菌株被分为9个PFGE带型。结论贵阳地区甲型副伤寒沙门菌流行复杂以2型和1型为优势流行带型,提示存在同一克隆群的菌株广泛传播。该研究进一步证实PFGE是一种发现或预警暴发的可行服务手段。     

医院获得性感染中出现携带SCCmecⅣ/Ⅴ的耐甲氧西林金黄色葡萄球菌

目的 研究某院临床分离的医院获得性耐甲氧西林金黄色葡萄球菌(HA-MRSA)的葡萄球菌染色体mec盒(SCCmec)分型及分子流行病学特征.方法 收集中南大学湘雅医院2012年1月~2012年12月临床分离的71株HA-MRSA,采用多重PCR进行SCCmec分型,PCR检测PVL毒素基因,并用脉冲场凝胶电泳(PFGE)分析菌株间的同源性.结果 71株HA-MRSA以SCCmecⅢ型为主,占69.0%(49/71),其次为SCCmecⅣ型、SCCmecⅤ型和SCCmecⅡ型,分别占14.1%(10/71)、4.2%(3/71)和4.2%(3/71),另有6株(8.5%)菌株未能分型.HA-SCCmecⅣ/ⅤMRSA感染者年龄显著低于HA-SCCmecⅠ/Ⅱ/ⅢMRSA感染者,携带PVL基因阳性率显著高于HA-SCCmecⅠ/Ⅱ/ⅢMRSA感染者,而两者入院至检出菌株的时间及住院天数均未见明显差异.HA-SCCmecⅣ/ⅤMRSA对左旋氧氟沙星、环丙沙星、利福平、庆大霉素、四环素等的耐药率均显著低于HA-SCCmecⅠ/Ⅱ/ⅢMRSA(P<0.05).13株HA-SCCmecⅣ/ⅤMRSA菌株在55%的相似度水平形成一个大的组群.按照≥85%的相似度,这些菌株共形成3个PFGE簇以及4个单一菌株的PFGE型.结论 在国内首次发现携带SCCmecⅤ型的HA-MRSA菌株,HA-SCCmecⅣ/ⅤMRSA已有在医疗机构传播的趋势,并成为医院内感染的重要来源.     

Detection and molecular typing of methicillin-resistant Staphylococcus aureus from northeastern part of India

BackgroundIn Staphylococcus aureus, methicillin resistance is exhibited by modifications in penicillin-binding protein that minimises the binding affinity to beta-lactam antibiotics. The present study investigated the occurrence of methicillin-resistant S. aureus (MRSA) in community-acquired infections, that is, community-acquired MRSA (CA-MRSA) and in-hospital–acquired infections, that is, hospital-acquired MRSA (HA-MRSA) from Northeast India.MethodsA total of 197 consecutive non-duplicate isolates were collected from Silchar Medical College and Hospital and other private diagnostic laboratories. The isolates were confirmed to be S. aureus at our centre. All isolates were subjected to antibiotic susceptibility testing and were screened for methicillin resistance using cefoxitin disc test. All MRSA were subjected to Polymerase Chain Reaction (PCR) assay for detection of mecA and mecC genes. DNA fingerprinting was performed for determining clonal diversity.ResultsSeventy-one isolates of 127 confirmed S. aureus were found to be methicillin resistant by screening test. mecA gene was detected in 43 isolates, and none of the isolates were positive for mecC gene. Linezolid and teicoplanin showed better activity with susceptibility pattern being 83.6% and 72.44%, respectively, whereas 66.14% were sensitive to vancomycin. Other antibiotic showed low level of activity. Pulsed Field Gel Electrophoresis (PFGE) showed 14 different banding patterns that suggest isolates were of different clonal types.ConclusionmecA was responsible for methicillin resistance in majority of strains. Polyclonal spread of MRSA infection in the study area indicates its diverse origin and possible lateral transfer. Thus, this study is of clinical interest in terms of selection of proper antimicrobial chemotherapy and infection control management.     

Antimicrobial resistance and molecular epidemiological characteristics of clinical isolates of Staphylococcus aureus in Changsha area

Background  Increasing prevalence of Staphylococcus aureus (S. aureus), particularly methicillin-resistant S. aureus (MRSA) has been reported in China. In this study, we investigated the drug resistance characteristic, genetic background, and molecular epidemiological characteristic of S. aureus in Changsha.

Methods  Between January 2006 and December 2008, 293 clinical isolates of S. aureus were collected from 11 hospitals in Changsha and identified by the Vitek-2 system. All the isolates were verified as MRSA by PCR amplification of both femA and mecA genes. K-B disk method was used to test drug sensitivity of S. aureus to antibiotics. Pulsed-field gel electrophoresis (PFGE) was performed for genotypic and homologous analysis of 115 isolates randomly selected from the original 293 clinical S. aureus isolates.

Results  S. aureus was highly resistant to penicillin, ampicillin, erythromycin, and clindamycin with resistant rates of 96.6%, 96.6%, 77.1%, and 67.2% respectively. All the isolates were susceptible to tecoplanin, vancomycin, and linezolid. MRSA accounted for 64.8% (190/293) of all the S. aureus strains. The 115 S. aureus isolates were clustered into 39 PFGE types by PFGE typing, with 13 predominant patterns (designated types A to M) accounting for 89 isolates. The most prevalent PFGE type was type A (n=56, 48.7%) and 100.0% of type A strains were MRSA. PFGE type A included 13 subtypes, and the most prevalent subtype was subtype A1 (46.4%, 26/56). Strains with PFGE type A were isolated from eight hospitals (8/11), and both subtypes A1 and A4 strains were isolated in a university hospital.

Conclusions  Clinical isolates of S. aureus in Changsha were resistant to multiple traditional antibiotics. There was an outbreak of PFGE type A MRSA in this area and the A1 subtype was the predominant epidemic clone. Dissemination of the same clone was an important reason for the wide spread of MRSA.     

Investigation of the prevalence of patients co-colonized or infected with methicillin-resistant Staphylococcus aureus and vancomycin- resistant enterococci in China: a hospital-based study

Background Nosocomial infection caused by methicillin-resistant Staphylococcus aureus （MRSA） and vancomycin-resistant enterococci （VRE） could lead to increased morbidity and mortality. In 2006, VRE nosocomial spread became a reality in our hospital since the first VRE nosocomial infection in 2003. Little is known about the prevalence of coexistence with VRE and MRSA in the patients. The primary objective of the study was to identify the molecular characteristics of epidemic MRSA clones in our hospital and the prevalence of the coexistence with MRSA and VRE in same patients during the 2-year period, 2006-2007. Methods The clinical features, laboratory test results, and therapeutic outcomes of 129 cases who isolated MRSA collected from January 2006 to December 2007 were retrospectively analyzed. Polymerase chain reaction （PCR） was used to determine mecA-femB type and staphylococcal cassette chromosome mec （SCCmec） type. All the participants were screened for clinical and microbiological data to identify the coexistence of VRE strains with MRSA. Results One hundred and twenty-nine MRSA isolates were included in the study： 71 （55%） from the intensive care unit, 35 （27.2%） from the surgical wards and 23 （17.8%） from the medical wards. The most frequent source of isolation of MRSA was sputum （76.7%）. From seven patients we isolated MRSA and VRE （E. faecium） simultaneously during their inpatient stay. One hundred and twenty-seven （127/129, 98.4%） MRSA isolates harboured SCCmec type Ⅲ, only 2 MRSA strains contained SCCmec type Ⅱ. All of the 129 MRSA isolates remained sensitive to vancomycin, teicoplanin and linezolid. Higher sensitivity rates were noted for chloramphenicol 99.2% （128/129）. Only 20.2% （26/129） of the MRSA isolates were sensitive to rifampin. All isolates presented resistance to multiple antimicrobial agents with high minimum inhibitory concentrations （MICs）, including： β-Iactams （penicillin, oxacillin, cefoxitin, and cefazolin）, tetracycline, erythromycin, gentamicin, and quinolones （ciprofloxacin, levofloxacin, and moxifloxacin）. Conclusions The predominant MRSA clone at Beijing Chaoyang Hospital from 2006 to 2007 had the type Ⅲ SCCmec element. All of the MRSA isolates were multiresistant to antimicrobial agents. Emergence of coexistence of MRSA and VRE in the same patient was not rare. Physicians should pay more attention to infections resulting from MRSA and VRE. Aggressive infection control measures should be taken to prevent the transmission of the multidrug resistance organism.     

北京市宋内氏志贺菌脉冲场凝胶电泳图谱研究

目的研究北京市2005～2006年分离的30株宋内氏志贺氏菌进行脉冲常凝胶电泳图谱特征。方法参照美国疾病预防控制中心PulseNet USA的统一方法进行脉冲常凝胶电泳,并对带型进行命名。采用BioNumerics图像分析软件做聚类分析。结果30株宋内氏志贺氏菌被分成17个带型,主要带型J16N11BJ0001到J16N11BJ0009的聚类相似性为92%,含概菌株占实验菌株总数的67%。结论建立北京市宋内氏志贺氏菌脉冲常凝胶电泳分析方法和初步带型数据库,获得了宋内氏志贺氏菌的主要克隆系。     

嗜麦芽窄食单胞菌医院感染特点及耐药性分析

目的分析近2年我院发生的嗜麦芽窄食单胞菌(SMA)医院感染的特点及耐药性,为控制感染和临床合理使用抗菌药物提供依据。方法采用美国临床实验室标准化委员会(NCCLS)推荐的纸片扩散法,检测从40例感染患者中分离的50株SMA对24种抗生素的耐药情况,通过脉冲场凝胶电泳(PFGE)全DNA指纹技术对菌株进行分型。结果 SMA感染主要发生在下呼吸道,50岁以上的患者居多,且多数为混合感染。SMA对头孢吡肟/舒巴坦、加替沙星、左氧氟沙星、氧氟沙星、敏感性高,而对多数抗菌药物耐药,对头孢曲松、头孢呋辛、头孢西丁的耐药率达到了100.0%,对亚胺培南、氨曲南、四环素、哌拉西林和庆大霉素耐药率分别为92.3%、88.9%、82.4%、75.0%和70.0%。多数SMA(17/21)没有同源性,仅一对同源菌株来自同一病房,另一对同源菌株来自医院的不同病房。结论患者被医院环境中自然存在的SMA定植可能是SMA基因组的多样性和低同源性的原因。头孢吡肟/舒巴坦、加替沙星、左氧氟沙星、氧氟沙星、头孢哌酮/舒巴坦是治疗SMA感染的有效药物。     

Community-acquired methicillin-resistant Staphylococcus aureus in a rural American Indian community

CONTEXT: Until recently, methicillin-resistant Staphylococcus aureus (MRSA) infections have been acquired primarily in nosocomial settings. Four recent deaths due to MRSA infection in previously healthy children in the Midwest suggest that serious MRSA infections can be acquired in the community in rural as well as urban locations. OBJECTIVES: To document the occurrence of community-acquired MRSA infections and evaluate risk factors for community-acquired MRSA infection compared with methicillin-susceptible S aureus (MSSA) infection. DESIGN: Retrospective cohort study with medical record review. SETTING: Indian Health Service facility in a rural midwestern American Indian community. PATIENTS: Patients whose medical records indicated laboratory-confirmed S aureus infection diagnosed during 1997. MAIN OUTCOME MEASURES: Proportion of MRSA infections classified as community acquired based on standardized criteria; risk factors for community-acquired MRSA infection compared with those for community-acquired MSSA infection; and relatedness of MRSA strains, determined by pulsed-field gel electrophoresis (PFGE). RESULTS: Of 112 S aureus isolates, 62 (55%) were MRSA and 50 (45%) were MSSA. Forty-six (74%) of the 62 MRSA infections were classified as community acquired. Risk factors for community-acquired MRSA infections were not significantly different from those for community-acquired MSSA. Pulsed-field gel electrophoresis subtyping indicated that 34 (89%) of 38 community-acquired MRSA isolates were clonally related and distinct from nosocomial MRSA isolates found in the region. CONCLUSIONS: Community-acquired MRSA may have replaced community-acquired MSSA as the dominant strain in this community. Antimicrobial susceptibility patterns and PFGE subtyping support the finding that MRSA is circulating beyond nosocomial settings in this and possibly other rural US communities.     

Bacteriophage types of methicillin-resistant Staphylococcus aureus in a tertiary care hospital

Background

Phage typing had been utilised extensively to characterise methicillin-resistant Staphylococcus aureus (MRSA) outbreak strains in the past. It is an invaluable tool even today to monitor emergence and dissemination of MRSA strains.

Aims

The aim of this study was to determine the prevalent phage types of MRSA in south India and the association between phage types, antibiotic resistance pattern and risk factors.

Method

A total of 48 non-duplicate MRSA strains recovered from various clinical samples during January to December, 2010 were tested against a panel of anti-staphylococcal antibiotics. Phage typing was carried out at the National Staphylococcal Phage Typing Centre, New Delhi. Out of 48, 32 hospitalised patients were followed up for risk factors and response to empirical and post sensitivity antibiotic therapy. The risk factors were compared with a control group of 30 patients with methicillin sensitive Staphylococcus aureus (MSSA) infection.

Results

Amongst the five prevalent phage types, 42E was most common (52%), followed by a non-typable variant (22.9%), 42E/47/54/75 (16.6%), 42E/47 (6.2%) and 47 (2%). Phage type 42E was the predominant strain in all wards and OPDs except in the ICU where 42E/47/54/75 was most common. Although not statistically significant, strain 42E/47/54/75 (n=8) showed higher resistance to all drugs, except ciprofloxacin and amikacin, and were mostly D-test positive (87.5%) compared to the 42E strain (32%). Duration of hospital stay, intravenous catheterisation and breach in skin were the most significant risk factors for MRSA infection.

Conclusion

We found MRSA strain diversity in hospital wards with differences in their antibiotic susceptibility pattern. The findings may impact infection control and antibiotic policy significantly.     

医院获得性耐甲氧西林金黄色葡萄球菌感染回顾性分析

目的：分析医院获得性耐甲氧西林金黄色葡萄球菌（MRSA）感染的高危因素、药物敏感率和临床转归,为临床诊治MRSA感染提供依据。方法对临床送检各类标本中分离出的110例次MRSA,按照科室分布、标本种类、药物耐药性及临床疗效等进行回顾性分析。结果医院获得性MRSA主要分布于ICU、神经内科、干部科,感染主要来源于痰液、手术切口分泌物、皮肤创面分泌物,分别占68.2%、11.8%和8.2%,对青霉素类、头孢菌素类、碳青霉烯类敏感率为0,对氟喹诺酮类、大环内酯类、氨基糖甙类抗生素呈不同程度耐药,对替考拉宁、替加环素、万古霉素、利奈唑胺、呋喃妥因和喹奴/达福普汀敏感率为100%;在ICU 90%以上的MR-SA感染患者为年龄80岁以上、侵入性操作和长期使用广谱抗生素,在非ICU病房则以住院时间长和接受手术者居多。结论 MR-SA感染多发生于有多个基础疾病和高危因素者,临床表现复杂多样,临床上应加强对MRSA的防控,且应根据药敏合理使用抗生素,降低耐药菌株产生的概率。     

多重耐药鲍曼不动杆菌中仅黏菌素敏感菌株的分子流行病学研究

目的从基因水平了解多重耐药鲍曼不动杆菌（MDR-AB）中仅黏菌素敏感鲍曼不动杆菌（COS-AB）的流行情况，为控制其流行暴发提供实验数据。方法收集并分析上海瑞金医院2004年6月至2005年5月136例COS—AB临床感染患者的临床资料，同时收集2004年5月至2004年12月临床分离的鲍曼不动杆菌66株，其中COS-AB33株，非黏菌素敏感鲍曼不动杆菌（non-COS-AB）33株，采用随机引物PCR（RAPD）和脉冲场凝胶电泳（PFGE）等分子流行病学方法和统计学方法分析其流行情况。结果证实2004年6月至2005年5月出现COS-AB的暴发流行，经RAPD（引物ERIC2、272）分型均为一个型别，而PFGE分型为两个型别，其中烧伤科COS-AB为PFGEB型，为单一克隆的科室内流行；而烧伤科以外的其他科室为A型，为科室间流行，且主要集中于外科系统。结论COS-AB交叉感染严重，应严格消毒隔离措施，加强对COS-AB在环境及患者中流行情况的严密监测。用PFGE对鲍曼不动杆菌进行分型更为精确。     

Epidemiologic Study of Pseudomonas aeruginosa in critical patients and reservoirs

BACKGROUND: Pseudomonas aeruginosa is a common cause of nosocomial infections, particularly in intensive care units (ICUs). The aim of this study was to characterize P. aeruginosa clinical isolates by comparing antimicrobial susceptibility patterns with the presence of plasmids and to establish the clonal relatedness by pulsed-field gel electrophoresis (PFGE) typing. METHODS: The patients included those with isolation of P. aeruginosa hospitalized for more than 48 h in the ICU from April to May 1998. Environmental and staff cultures were obtained simultaneously. Minimal inhibitory concentrations, plasmid DNA profiles, and PFGE genomic patterns of enzyme restriction chromosomal DNA were compared. RESULTS: Sixty P. aeruginosa isolates were obtained from 197 clinical specimens, 178 environmental samples, and 47 hand cultures of personnel. Antimicrobial resistance was as follows: tobramycin 100%; ticarcillin, cefotaxime, ceftriaxone, ceftazidime, and gentamicin 80%; cefepime 60%; amikacin, ticarcillin/clavulanate, imipenem, and meropenem 40%; piperacillin and norfloxacin 20%; carbenicillin 12%, and ciprofloxacin 0%. Plasmids were detected in 11 isolates (18%). PFGE typing showed that 23 isolates belonged to a common clone (pattern A), identified from five patients, two nurses, and 10 environmental samples. Ten isolates were grouped in four clusters and 27 isolates had unrelated genomic patterns. There was no relationship among DNA genomic patterns, plasmid profiles, and susceptibility patterns. CONCLUSIONS: PFGE demonstrated the existence of a common clone in a critical care area. Reinforcement of infection control measures is needed to avoid horizontal transmission and severe infections.     

Pattern of bacteria and their antimicrobial susceptibility isolated from inanimate objects and hospital personnel

Different inanimate samples collected from surgery wards and general operation theatre (GOT) as well as animate samples from surgery personnel were subjected to aerobic culture with the aim of identifying source of infections in surgical cases. The pattern of aerobic bacteria with antibiotic susceptibility isolated from those samples were reported in the present study. Out of 91 such samples, 53 and 26 were from different locations in general wards and OT respectively and 12 were comprising of hand swabs, throat swabs and nasal swabs from surgery personnel. Pathogenic bacteria were isolated from 34 samples having Pseudomonas spp. (18/34) in the top of the list followed by Esch. coli (14). Among the Esch.coli isolates resistance to cotrimoxazole, amoxicillin and doxycycline were 78.7%, 71.4% and 57.1% respectively, whereas sensitivity to aztreonam, ceftazidime, gentamicin and ciprofloxacin were 100%, 85.8%, 78.7% and 71.4% respectively. Ceftriaxone yielded intermediate sensitive results in 21.4% strains. Isolates of Pseudomonas spp. also showed very high sensitive results to aztreonam, ceftazidime and ceftriaxone (94.7%, 94.7% and 84.2% respectively). Ciprofloxacin and gentamicin were sensitive in 68.4% and 57.9% respectively. Susceptibility pattern showed well correlation with clinical response in infected cases.     

耐甲氧西林金黄色葡萄球菌的检测及耐药性分析

目的 分析耐甲氧西林金黄色葡萄球菌的临床感染现状及耐药性.方法 采用美国MicroScan全自动细菌分析仪鉴定细菌种类,并用纸片扩散法进行药敏试验.结论 2006～2007年共分离出金黄色葡萄球菌270株,其中,耐甲氧西林金黄色葡萄球菌(MRSA)174株,检出率为64.4%.所有的分离株对万古霉素都敏感;MRSA对 红霉素、克林霉素、庆大霉素、复方磺胺、利福平和左旋氧氟沙星的耐药率分别为94.8%、71.8%、67.8%、85.1%、15.5%和48.9%.结论MRSA的分离率显著增高,耐药性严重,临床细菌室应高度重视MRSA的检测.     

儿童标本中分离MRSA的SCCmec基因分型及耐药性分析

目的 了解亳州地区儿童耐甲氧西林金黄色葡萄球菌(methicillin resistant staphylococcus aureus,MRSA)的SCCmec基因分型及其耐药性。 方法 收集2018年12月—2019年3月亳州市人民医院儿科共6个病区临床分离的89株MRSA菌株,采用PCR方法对其进行SCCmec基因分型;VITEK 2 compact全自动微生物分析仪进行抗菌药物敏感性试验,并采用WHONET 5.6软件统计药敏结果并进行分析。 结果 89株MRSA以SCCmecⅣa型为主,占55.1%(49/89),其次SCCmecⅢ型12.4%(11/89),SCCmecⅡ型1.1%(1/89),未分型31.4%(28/89),未见SCCmecⅠ型和Ⅴ型;89株MRSA对青霉素均耐药,对红霉素、克林霉素均高耐药,耐药率分别为87.6%、62.9%,对喹诺酮类、庆大霉素、甲氧苄啶/磺胺甲恶唑的耐药率均低于10%;而49株SCCmecⅣa型对红霉素、克林霉素的耐药率略升高,分别为91.8%、77.6%,对喹诺酮类药物耐药率4.1%,有所下降,而对甲氧苄啶/磺胺甲恶唑、庆大霉素均敏感;以上菌株未发现对万古霉素、利奈唑胺、奎奴普丁/达福普汀及替加环素耐药。 结论 目前亳州地区儿童分离的MRSA主要以SCCmecⅣa型为主要流行株,对多种抗菌药物呈不同程度耐药。      

珠海市斯坦利沙门菌耐药特征和分子分型分析

目的分析2012—2016年珠海市斯坦利沙门菌的耐药情况与脉冲场凝胶电泳(PFGE)分子分型。方法将腹泻病人的粪便进行沙门菌分离培养,生化鉴定和血清学分型,采用药敏纸片法(K-B法)进行12种抗生素的耐药试验。根据美国PulseNet实验室推荐的沙门菌PFGE分型试验方案进行分子分型。结果分离培养共获得斯坦利沙门菌108株,检出高峰期在7—10月,主要感染人群是小于1岁的幼儿(55.6%),感染病例男女比为1.84∶1。药敏试验显示本地斯坦利沙门菌对庆大霉素、三代和四代头孢类抗生素及环丙沙星较为敏感,对复方磺胺类抗生素耐药率为64.8%(70/108),对氨苄青霉素、萘啶酮酸、四环素、氯霉素和链霉素呈现低水平的耐药(10.2%~16.7%),但对链霉素的中度敏感率为68.5%,有18株(16.7%)菌呈多重耐药。108株菌经PFGE分型分为6个聚类簇,共获得66种带型,每种带型包含菌株数1~21株不等,相似值在62.4%~100%,优势带型为ST15(21株)和ST18(10株)。结论珠海市斯坦利沙门菌的耐药情况较为乐观,但对磺胺类抗生素耐药率比较高,也出现多重耐药株,需继续加强监测。斯坦利沙门菌遗传基因多样性,多重耐药株的型别多样,菌株来源广泛。     

大肠埃希菌临床分离株的基因组结构分型研究

目的 通过基因组结构分析对临床分离的大肠埃希茵进行分型，并探讨型别与临床疾病的关系。方法 取临床不同疾病病人的痰、尿、血、分泌物等标本，分离大肠埃希菌。用I-CeuI酶切全基因组DNA以及用脉冲场凝胶电泳分离DNA片段后，根据酶切图谱的异同进行分型。结果 从临床上分离的64株大肠埃希菌中，62株有7个I-CeuI酶切住点，2株有8个I-CeuI酶切位点。菌株间I-CeuI酶切图谱差异明显。这些菌株根据基因组结构的差异分为32个型，某些疾病与特定基因组型密切相关。结论 临床分离的大肠埃希菌基因组结构存在多样性，其与临床疾病之间存在一定的对应关系，但尚需大宗病例进一步研究。     

中央空调冷却塔水嗜肺军团菌PFGE分子分型

目的 了解中山市中央空调冷却塔水血清1型（LP1）及血清7型（LP7）嗜肺军团菌脉冲场凝胶电泳（PFGE）分子分型情况。方法 对2012—2014年从中山市部分酒店、娱乐场所、商场、医院等公共场所中央空调冷却塔水样本中分离出的41株LP1型嗜肺军团菌和12株LP7型嗜肺军团菌进行脉冲场凝胶电泳,运用Bio Numerics6.6软件进行聚类分析。结果 按照100%的相似程度,41株LP1型嗜肺军团菌分为26种PFGE型别,每个带型包括1~6株菌,菌株之间的相似系数为16.6%~100%;12株LP7型嗜肺军团菌分为10种PFGE型别,每个带型包括1~2株菌,菌株之间的相似系数为19.3%~100%。不同地区和不同年份分离的菌株存在相同的PFGE型别;同一场所可存在相同的PFGE型别,也可跨月份或年份存在不同的型别。按照90%以上的相似程度, LP1型嗜肺军团菌有4个克隆群,包含的菌株数和PFGE带型占其血清型别分离株总数以及PFGE型别总数的51.2%（21/41）和30.8%（8/26）;LP7型嗜肺军团菌有2个克隆群,包含的菌株数和PFGE带型占其血清型别分离株总数以及PFGE型别总数的50.0%（6/12）和40.0%（4/10）。克隆群在空间和时间分布上无明显差异。结论 中山市中央空调冷却塔水中LP1型及LP7型嗜肺军团菌分离株存在广泛的PFGE基因型别,未形成某一优势基因群的地区优势及时间趋势。