金黄色葡萄球菌生物膜形成及相关基因分析

目的探讨金黄色葡萄球菌生物膜表型与相关基因的关系。方法收集100株临床分离的金黄色葡萄球菌,用刚果红培养基法进行生物膜筛选;用电子显微镜观察生物膜的形成;用PCR方法检测生物膜相关基因。结果 100株金黄色葡萄球菌中,79株产生生物膜,阳性率为79.0%。ebh、icaA、icaD、fnbA的检出率分别为53.2%、94.9%、94.9%、81%。金黄色葡萄球菌生物膜阳性菌株和生物膜阴性菌株之间生物膜相关基因ebh、icaA、icaD、fnbA的阳性率差异有统计学意义(P0.01)。结论ebh、icaA、icaD、fnbA 4种基因与金黄色葡萄球菌生物膜形成密切相关。     

血流感染金黄色葡萄球菌毒力基因、agr分型及生物膜形成能力调查

目的 探讨血液来源金黄色葡萄球菌耐药性、毒力基因、agr分型、生物膜形成能力，并比较甲氧西林敏感株与耐药株间的差异。方法 收集2019年1月—2020年12月102株血液分离非重复金黄色葡萄球菌菌株，采用全自动微生物鉴定药敏分析系统进行药物敏感性检测；采用PCR及多重PCR分析菌株毒力基因携带情况及agr基因多态性；采用96孔板结晶紫染色法检测生物膜形成能力。采用卡方检验和Fisher精确概率法比较分析甲氧西林耐药金黄色葡萄球菌(MRSA)和甲氧西林敏感金黄色葡萄球菌(MSSA)菌株间耐药性、毒力基因、agr分型及生物膜形成能力的差异。结果 102株金黄色葡萄球菌中，43株为MRSA,59株为MSSA。毒力基因普遍表达葡萄黄质蛋白基因crtN(99.0%)、溶血素基因(hla 97.1%、hlb 98.0%、hld 96.1%),其次为表面因子CP8合成酶基因cap8H(34.3%)、中毒性休克综合征毒素-1基因tst(21.6%),其中携带crtN/hla/hlb/hld 4种毒力基因组合的菌株最多(48株)。agr分型阳性率为97.1%,其中agrⅠ型占56.9%,agrⅡ型占36...     

医院分离金黄色葡萄球菌的毒力基因和耐药基因的研究

目的研究医院分离金黄色葡萄球菌临床株的毒力基因和耐药基因携带情况,为加强医院感染控制提供科学依据。方法采用分离培养与鉴定方法和多重基因扩增技术对金黄色葡萄球菌临床分离株进行了毒力基因和耐药基因检测,同时进行药敏试验。结果在医院采集的5 088份样品中,分离出25株金黄色葡萄球菌,阳性率为0.49%,其中耐甲氧西林菌株占12%。检测出主要毒力基因SEA-E携带率为52%,检出ETA携带率为12%,PVL、ETB和TSST-1等携带率均比较低。检出耐药基因主要是tetM,携带率为44%,erm携带率为24%。临床分离的金黄色葡萄球菌对常用12种抗菌药物都不同程度耐药,主要耐药基因和相应耐药表型结果基本一致。结论医院分离的金黄色葡萄球菌携带较多的毒力因子和耐药因子,MRSA具备多重耐药性,耐药表型和耐药基因检测结果相一致。     

血流感染金黄色葡萄球菌毒力基因、agr分型及生物膜形成能力调查*

摘要:目的探讨血液 来源金黃色葡萄球菌耐药性、毒力基因、agr 分型、生物膜形成能力,并比较甲氧西林敏感株与耐药株间的差异。方法收集2019年1月一2020年12月102株血液分离非重复金黃色葡萄球菌茵株,采用全自动微生物鉴定药敏分 析系统进行药物敏感性检测;采用PCR及多重PCR分析菌株毒力基因携带情况及agr基因多态性;采用96孔板结晶紫染色法检测生物膜形成能力。采用卡方检验和Fisher 精确概率法比较分析甲氧西林耐药金黄色葡萄球菌(MRSA)和甲氧西林敏 感金黃色葡萄球菌(MSSA)菌株间耐药性、毒力基因、agr 分型及生物膜形成能力的差异。结果102 株金黄色葡萄球菌中,43株为MRSA,59株为MSSA。毒力基因普遍表达葡萄黃质蛋白基因crtN(99.0%)、溶血素基因(hla 97. 1%、hlb 98. 0%、hld 96.1%),其次为表面因子CP8合成酶基因cap8H(34.3%)、中毒性休克综合征毒素-1基因tst( 21.6%),其中携带crtN/hla/hlb/hld 4种毒力基因组合的菌株最多(48株)。agr分型阳性率为97.1%,其中agr I型占56.9% ,agr I型占36.3%,agr I型占 4.9%,未检测出agt IV型,agr 未获分型3株。生物膜形成阳性共28株,其中12株可形成强生物膜。MRSA菌株对环丙沙星、四环素、红霉素、克林霉素、左氧氟沙星、莫西沙星的耐药率高于MSSA菌株(P<0.05) ;MRSA菌株tst基因携带率高于MSSA (P<0.01) ,cap8H基因携带率低于MSSA(P<0.05),差异有统计学意义;MRSA菌株中agr I和agr I型各占46.51 %和48.84% ;MRSA菌株更倾向形成中等或弱生物膜,与MSSA菌株相比在生物膜形成能力上差异无统计学意义。结论临床分 离血流感 染金黄色葡萄球菌存在多种毒力基因、agr分型、生物膜形成能力,需加强监测。     

北京市昌平区食源性金黄色葡萄球菌药敏分析及分子流行病学特征研究

目的 对北京市昌平区2011-2014年分离获得的74株食源性金黄色葡萄球菌耐药谱、毒力因子编码基因携带情况和分子流行病学特征进行研究分析,为金黄色葡萄球菌食源性疾病的预防控制提供参考。方法 依据GB 4789.10-2010进行菌株分离和鉴定,用全自动微生物鉴定及药敏分析系统VITEK2 Compact进行16种药物敏感性试验,并使用检测试剂盒进行－内酰胺酶的检测;利用PCR方法检测分离菌株肠毒素,杀白细胞素和耐热磷酸酶等毒力因子编码基因;脉冲场凝胶电泳(PFGE)方法对分离株进行分子分型。结果 74株金黄色葡萄球菌中68株(91.89%)有不同程度的耐药,其中对青霉素耐药率(87.84%)最高,其次为红霉素(44.59%)和克林霉素(39.19%)。毒力因子检测结果显示肠毒素阳性率64.86%(48/74),产2种以上肠毒素菌株占72.92%(35/48)。耐热磷酸酶阳性率89.19%,杀白细胞素编码基因lukF阳性率77.03%。PFGE分型结果显示除9株菌不可分型外,其余65株菌分为40个不同型别,无优势型别。结论 昌平区2011-2014年分离的食源性金黄色葡萄球菌具有较强的耐药性、分子多态性和毒力因子携带率较高的特征,说明这些菌株可以导致潜在的食品安全问题。     

91株金黄色葡萄球菌毒力基因和耐药基因分布研究

目的探讨91株金黄色葡萄球菌菌株的毒力基因和耐药基因分布。方法采用PCR方法检测金黄色葡萄球菌30个毒力基因和13个耐药基因。结果毒力基因除肠毒素基因see和sep,其他28个均可在91株金黄色葡萄球菌菌株中检测到,且某些毒力基因如溶血素基因hla、hld、hlg-v和杀白细胞毒素基因lukED的阳性率较高(80%);耐药基因除氨基糖苷类耐药基因ant4′,其他12个均可在91株金黄色葡萄球菌菌株中检测到,特别是青霉素耐药基因blaZ,阳性率达100%。结论金黄色葡萄球菌流行株均携带多个毒力基因和耐药基因。     

上海地区859名青少年鼻腔金黄色葡萄球菌携带及耐药状况调查

目的了解上海地区青少年鼻腔金黄色葡萄球菌的携带率及耐药情况。方法用鼻拭子法采集859名学生鼻腔样本,采用革兰染色、鸟氨酸脱羧酶试验、DNA酶试验、高盐甘露醇平板生长试验和血浆凝固酶试验(试管法)鉴定金黄色葡萄球菌,纸片扩散法体外药物敏感性试验进行耐药性分析,聚合酶链反应(PCR)检测金黄色葡萄球菌A蛋白(SPA)分型和杀白细胞毒素(PVL)毒力基因。结果该校在校生鼻腔金黄色葡萄球菌的携带率为7.0%(60株),耐甲氧西林金黄色葡萄球菌(MRSA)为0.0%,PVL毒力因子阴性,SPA分型1株为spa基因阴性,其余59株呈现克隆多样性,发现3个新的spa型。结论该校青少年鼻腔中金黄色葡萄球菌的携带率低,未发现MRSA。     

引起压疮感染的金黄色葡萄球菌生物膜形成情况及耐药性分析

目的 了解该院压疮感染患者标本中分离的金黄色葡萄球菌的人群分布、生物膜形成情况及耐药情况等流行病学特征,为临床提供重要依据。方法 2019年5月至2022年5月该院共收集到与压疮感染相关的金黄色葡萄球菌126株,采用Vitek MS质谱仪进行细菌鉴定,药敏试验采用纸片扩散法(K-B法),按美国临床实验室标准化协会2016-M100的标准进行药敏结果分析,用结晶紫染色法检测金黄色葡萄球菌生物膜并对生物膜形成能力进行判定,生物膜中分别加入葡萄糖和银离子粉末,观察其对生物膜形成的影响。结果 该院共收集到与压疮感染相关的金黄色葡萄球菌126株,各年龄段及各级压疮均有检出。形成生物膜的菌株占73.00%,其中Ⅳ期压疮分离的菌株形成生物膜的菌株比例(81.81%)高于其他分期(Ⅱ、Ⅲ期)分离的菌株(63.33%),差异有统计学意义(P<0.05);不同生物膜形成能力的菌株对青霉素G、四环素、环丙沙星、磺胺甲噁唑/甲氧苄啶的耐药率较高,对替考拉宁、左氧氟沙星的耐药率较低,未检出对万古霉素耐药的革兰阳性菌,不同生物膜级别金黄色葡萄球菌的耐药性比较,差异无统计学意义(P>0.05);11.1...     

金黄色葡萄球菌sasX、psm-mec、pvl三种毒力基因的检测与分析

摘要：目的：分析54株金黄色葡萄球菌的mecA基因与sasX、psm mec、pvl三种毒力基因分布及临床相关性。 方法：收集2013年1～5月南京医科大学第一附属医院临床分离的54株金黄色葡萄球菌,用PCR及测序的方法分析mecA、sasX、psm-mec、pvl基因的携带情况,并结合患者的临床资料,探讨其临床相关性。 结果：54株金黄色葡萄球菌中有23株mecA基因检测阳性,31株mecA基因阴性。mecA基因阳性菌株较mecA基因阴性株体外药敏试验呈多重耐药表型。sasX基因阳性1株,阳性率为1.9%;psm-mec基因阳性10株,阳性率为18.5%;pvl基因阳性38株,阳性率为70.4%。mecA基因阳性菌株psm-mec基因阳性率显著高于mecA基因阴性菌株（P<0.01）,pvl基因阳性率显著低于mecA基因阴性菌株（P<0.05）。mecA基因和psm-mec基因与临床感染严重程度显著相关（P均<0.01）。 结论：联合检测mecA、psm-mec和pvl基因有利于金黄色葡萄球菌感染的诊断、治疗和预后综合评估。     

葡萄球菌耐消毒剂基因qacA／B检测及临床意义

目的 了解临床分离的葡萄球菌mecA基因及耐消毒剂基因qacA/B的存在状况.方法 临床分离的40株葡萄球菌,分别用头孢西丁(30 μg)筛查法和聚合酶链反应(PCR)法检测mecA基因,同时采用PCR法检测其耐消毒剂基因qacA/B.结果 40株葡萄球菌中36株mecA基因阳性,占90.0%(36/40);11株检出qacA/B基因者均为mecA阳性葡萄球菌,其中10株为耐甲氧西林金黄色葡萄球菌(MRSA),1株为耐甲氧西林凝固酶阴性葡萄球菌(MRCNS),qacA/B阳性率为27.5%(11/40).结论 含qacA/B基因的葡萄球菌全部为mecA基因阳性,提示对临床常用消毒剂耐药的金黄色葡萄球菌同时也对甲氧西林耐药.因此检测葡萄球菌耐消毒剂基因,对合理选用消毒剂,控制葡萄球菌感染传播具有临床意义.     

金黄色葡萄球菌生物膜形成与ica操纵子关系探讨

目的了解不同部位分离金黄色葡萄球菌在不同时间生物膜形成与ica操纵子关系。方法采用结晶紫法测定不同部位在不同时间形成生物膜的含量;采用PCR法测定菌株是否含有ica基因。结果生物膜形成能力强的菌株则ica基因大部分为阳性。结论含有ica基因的金黄色葡萄球菌则生物膜形成的能力较强。     

临床分离表皮葡萄球菌相关基因与生物膜表型的关系

目的：分析临床分离表皮葡萄球菌 icaA、aap 、atlE、sarA 基因与生物膜表型的关系。方法收集临床分离的表皮葡萄球菌78株,采用 PCR 法扩增 icaA、aap 、atlE、sarA 基因,组织细胞培养板黏附法检测生物膜表型,χ2检验分析上述基因与生物膜表型的关系,Wilcoxon 符号秩检验分别分析 icaA ＋菌及 icaA -菌在胰酶大豆肉汤（TSB）与TSB＋3％氯化钠中生物膜表型光密度（OD）值的差异。结果78株表皮葡萄球菌 icaA、aap 、atlE、sarA 基因阳性率分别为24．4％（19/78）、79．5％（62/78）、73．8％（57/78）、82．1％（64/78）。产生物膜株阳性率为51．3％（40/78）,其中高产生物膜16株,均携带 icaA 基因;弱产生物膜24株。经统计学分析,上述基因与生物膜表型之间有相关性,icaA 基因与高产生物膜表型有相关性。icaA ＋菌及 icaA -菌在 TSB 与TSB＋3％氯化钠中生物膜 OD 值的差异有统计学意义（P ＜0．05）。结论表皮葡萄球菌生物膜表型涉及多种因子参与,而 icaA 基因有助于高产生物膜表型形成。环境因素也可影响表皮葡萄球菌生物膜表型。     

葡萄球菌生物膜的形成及影响因素

目的了解临床标本中葡萄球菌形成生物膜的状况，及葡萄糖、乙醇、氯化钠对生物膜形成的影响。方法采用刚果红、微量平板法检测生物膜形成及葡萄糖、乙醇、氯化钠对生物膜形成的影响。结果刚果红法检测金黄色葡萄球菌(金葡菌)、凝固酶阴性葡萄球菌(CNS)生物膜阳性率分别为26．2％和12．7％；生物膜半定量法，金葡菌：普通肉汤、0．25％葡萄糖、2％、4％乙醇、2％、4％氯化钠阳性率分别为14．7％、29．6％、32．7％、19．6％、13．1％和14．6％；CNS分别为13．9％、27．8％、26．5％、18．5％和21．5％。结论临床标本葡萄球菌相当一部分能产生生物膜，葡萄糖、乙醇能促进生物膜形成。     

表皮葡萄球菌生物膜形成与细菌耐药性的相关性分析

目的探讨表皮葡萄球菌临床分离株生物膜的形成情况,分析其生物膜形成与细菌耐药性的相关性。方法收集2014年1月至2015年2月住院患者血标本分离出的表皮葡萄球菌62株,采用生物膜形成试验和聚合酶链式反应(PCR)扩增试验检测细菌生物膜,并采用纸片扩散法(K-B法)进行细菌药物敏感性试验。结果利用生物膜形成试验检出生物膜阳性菌株23株,检出率为37.1%;PCR扩增试验检出icaA基因27株,检出率为43.5%,差异无统计学意义(P0.05);两种方法同时阳性的菌株为14株。生物膜阳性菌株对所测抗菌药物的耐药率普遍高于生物膜阴性菌株,其中对庆大霉素、青霉素G、苯唑西林、左旋氧氟沙星、头孢西丁的耐药率比较差异有统计学意义(P0.05),所有菌株对万古霉素、利奈唑胺、奎奴普丁/达福普汀均敏感。结论两种方法对表皮葡萄球菌生物膜的检出率无明显差异,生物膜阳性菌株耐药率普遍高于生物膜阴性菌株。     

Inhibition of biofilm formation by esomeprazole in Pseudomonas aeruginosa and Staphylococcus aureus

Staphylococcus aureus and Pseudomonas aeruginosa are common nosocomial pathogens responsible for biofilm-associated infections. Proton pump inhibitors (PPI), such as esomeprazole, may have novel antimicrobial properties. The objective of this study was to assess whether esomeprazole prevents sessile bacterial growth and biofilm formation and whether it may have synergistic killing effects with standard antibiotics. The antibiofilm activity of esomeprazole at 0.25 mM was tested against two strains each of S. aureus and P. aeruginosa. Bacterial biofilms were prepared using a commercially available 96-peg-plate Calgary biofilm device. Sessile bacterial CFU counts and biomass were assessed during 72 hours of esomeprazole exposure. The killing activities after an additional 24 hours of vancomycin (against S. aureus) and meropenem (against P. aeruginosa) treatment with or without preexposure to esomeprazole were also assessed by CFU and biomass analyses. P. aeruginosa and S. aureus strains exposed to esomeprazole displayed decreased sessile bacterial growth and biomass (P < 0.001, each parameter). After 72 h of exposure, there was a 1-log(10) decrease in the CFU/ml of esomeprazole-exposed P. aeruginosa and S. aureus strains compared to controls (P < 0.001). After 72 h of exposure, measured absorbance was 100% greater in P. aeruginosa control strains than in esomeprazole-exposed strains (P < 0.001). Increased killing and decreased biomass were observed for esomeprazole-treated bacteria compared to untreated controls exposed to conventional antibiotics (P < 0.001, each parameter). Reduced biofilm growth after 24 h was visibly apparent by light micrographs for P. aeruginosa and S. aureus isolates exposed to esomeprazole compared to untreated controls. In conclusion, esomeprazole demonstrated an antibiofilm effect against biofilm-producing S. aureus and P. aeruginosa.     

Modification of the Congo red agar method to detect biofilm production by Staphylococcus epidermidis

Staphylococcus epidermidis in immunocompromised patients can cause bacteremia related to the use of catheter due to biofilm production. There are different phenotypic methods to detect biofilm formation. One method is based on culture in brain heart infusion agar (BHIA) containing sucrose and red Congo dye (original Congo red agar). Our group created a new CRA formula and we have confirmed its capacity to detect biofilm production in 210 S. epidermidis strains, including 76 (36.2%) icaAB gene–positive strains. Other parameters were also evaluated. The new CRA formula that gave the best results was BHIA with sucrose (5%), Congo red (0.08%), NaCl (1.5%), glucose (2%), and vancomycin (0.5 mg/mL) (vancomycin-modified CRA—CRAmod). The CRAmod plus vancomycin may be a promising tool and can help to determine the real participation of S. epidermidis in the infectious process.     

Epidemiology, treatment, and prevention of community-acquired methicillin-resistant Staphylococcus aureus infections

Since first described In 1961, methicillin-resistant Staphylococcus aureus (MRSA) has become a common nosocomial pathogen. Substantial increases in MRSA infections among nonhospitalized patients are being reported. Methicillin-resistant S. aureus is the most common isolate from skin and soft tissue infections in selected centers in the United States. Community-acquired MRSA strains differ from nosocomial strains in clinically relevant ways, such as in their propensity to cause skin and soft tissue infection and severe necrotizing pneumonia. Clinicians in numerous specialties, particularly primary care physicians, will likely evaluate patients presentIng with community-acquired MRSA and should become familiar with the epidemiology and clinical characteristics of and evolving therapeutic and preventive strategies for this infection.     

Effect of farnesol on Staphylococcus aureus biofilm formation and antimicrobial susceptibility

Staphylococcus aureus is among the leading pathogens causing bloodstream infections able to form biofilms on host tissue and indwelling medical devices and to persist and cause disease. Infections caused by S. aureus are becoming more difficult to treat because of increasing resistance to antibiotics. In a biofilm environment particularly, microbes exhibit enhanced resistance to antimicrobial agents. Recently, farnesol was described as a quorum-sensing molecule with possible antimicrobial properties. In this study, the effect of farnesol on methicillin-resistant and -susceptible strains of S. aureus was investigated. With viability assays, biofilm formation assessment, and ethidium bromide uptake testing, farnesol was shown to inhibit biofilm formation and compromise cell membrane integrity. The ability of farnesol to sensitize S. aureus to antimicrobials was assessed by agar disk diffusion and broth microdilution methods. For both strains of staphylococci, farnesol was only able to reverse resistance at a high concentration (150 microM). However, it was very successful at enhancing the antimicrobial efficacy of all of the antibiotics to which the strains were somewhat susceptible. Therefore, synergy testing of farnesol and gentamicin was performed with static biofilms exposed to various concentrations of both agents. Plate counts of harvested biofilm cells at 0, 4, and 24 h posttreatment indicated that the combined effect of gentamicin at 2.5 times the MIC and farnesol at 100 microM (22 microg/ml) was able to reduce bacterial populations by more than 2 log units, demonstrating synergy between the two antimicrobial agents. This observed sensitization of resistant strains to antimicrobials and the observed synergistic effect with gentamicin indicate a potential application for farnesol as an adjuvant therapeutic agent for the prevention of biofilm-related infections and promotion of drug resistance reversal.     

In vitro effects of antimicrobial agents on planktonic and biofilm forms of Staphylococcus lugdunensis clinical isolates

Staphylococcus lugdunensis is an atypically virulent coagulase-negative staphylococcal species associated with acute and destructive infections that often resemble Staphylococcus aureus infections. Several types of infection caused by S. lugdunensis (e.g., native valve endocarditis, prosthetic joint infection, and intravascular catheter infection) are associated with biofilm formation, which may lead to an inability to eradicate the infection due to the intrinsic nature of biofilms to resist high levels of antibiotics. In this study, planktonic MICs and MBCs and biofilm bactericidal concentrations of 10 antistaphylococcal antimicrobial agents were measured for 15 S. lugdunensis isolates collected from patients with endocarditis, medical device infections, or skin and soft tissue infections. Planktonic isolates were susceptible to all agents studied, but biofilms were resistant to high concentrations of most of the drugs. However, moxifloxacin was able to kill 73% of isolates growing in biofilms at 相似文献