Ophthalmic methicillin-resistant <i>Staphylococcus aureus</i>infections: Sensitivity and resistance profiles of 65 isolates in central California

Purpose: To capture the sensitivity and resistance trends of ophthalmic Methicillin-resistant Staphylococcus aureus (MRSA) in a heterogenous demographic. Methods: Between 1/1/2004-12/31/2011, ophthalmic MRSA infections were searched in the electronic medical record system ofCommunityRegionalMedicalCenterinFresno,California. We reviewed whether the infection was community-acquired or hospital-acquired, culture site, and sensitivity/resistance profiles. Results: The ophthalmic MRSA isolates tested for vancomycin, sulfamethoxazole-trimethoprim, and gentamycin were 100% sensitive to these to these antibiotics. Tetracycline and rifampin had the next highest sensitivity to resistance ratio, followed by clindamycin. More cases were community-acquired than hospital acquired. Almost half of the hospital-acquired cases were in newborns. Most hospital acquired infections were post-ophthalmic surgery. Conclusion: There is an increasing trend of community- acquired ophthalmic MRSA infection with eyelid involvement being the most common manifestation. Hospital-acquired cases are common in newborns and post-ophthalmic surgery. Have a high index of suspicion for MRSA infection with suspected “insect bites”. Vancomycin, sulfamethoxazole-trimethoprim, gentamycin, tetracycline, and rifampin are good choices to treat ophthalmic MRSA infection. There may be emerging resistance to clindamycin, at least in theCentral Californiaregion. If MRSA infection is suspected, erythromycin and fluoroquinolones should be avoided.

Antibacterial Activity of Exogenous Glutathione and Its Synergism on Antibiotics in Methicillin-Associated Multidrug Resistant Clinical Isolates of Staphylococcus aureus

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most problematic human pathogens. Antibiotic treatment of MRSA often associated with resistance to multiple classes of antibiotics is extremely challenging and urgently demands action to treat MRSA. Glutathione (GSH) is a biogenic thiol-compound that maintains an optimal intracellular redox-potential required for various normal cellular processes. Antibacterial activity of exogenous GSH has been reported in some bacterial pathogens but is largely unknown in MRSA. Aim: This study aimed to understand antibacterial activity of GSH, its role in antibiotic susceptibility, and a potential antibacterial mechanism in clinical isolates of S. aureus. Materials and Methods: Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), checkerboard, time-killing, and bacterial killing assays were performed for 14 clinical isolates of S. aureus including 10 MRSA and two type strains (ATCC 700699 and 35556). Results: MIC and MBC levels for the clinical and type strains were 15 - 20 mM and 25 - 40 mM of GSH, respectively. Subinhibitory concentrations of GSH synergistically enhanced susceptibility of all tested-antibiotics, resulting in sensitizing all-tested S. aureus. Bacterial-killing produced by GSH-mediated acidity was significantly higher than that by hydrochloric acid-mediated acidity. Conclusion: Overall results concluded that GSH exhibited antibacterial activity on S. aureus regardless of antibiotic susceptibility and synergistically enhanced antibiotic susceptibility. Additionally, GSH-mediated acidity was one of the antibacterial mechanisms. These findings suggest that GSH may be a potential antimicrobial agent or adjuvant for the conventional anti-MRSA regimens.

Incidence of Methicillin Resistant Staphylococcus aureus in Burn Patients Admitted to Burn Unit, Dhaka Medical

Staphylococcus aureus infection remains an increasing problem for higher morbidity and mortality in burn patients. We sought to determine the frequency of methicillin-resistant S. aureus (MRSA) in burn wound patients and study their drug resistance genes. Samples were collected (August 2010 to October 2011) from burn unit of Dhaka Medical College Hospital (DMCH), Bangladesh. MRSA was identified by conventional culture based methods. S. aureus was confirmed in 44.44% burn wound samples and 22.5% of the isolates were oxacillin resistant. All the S. aureus isolates were resistant to commonly used drugs like amoxicillin, azactam, erythromycin, azithromycin etc. and were sensitive to imipenem. The isolates were devoid of plasmid and the gene mecA, femA and IS431 were detected in their chromosomal DNA. Computational analysis of mecA gene sequence showed homology to S. aureus “penicillin binding protein 2a” (PBP-2a). The higher association of MRSA is in burn unit of DMCH, Bangladesh is alarming and with inappropriate antibiotic use, and the situation gets even complicated to treat. Therefore, the detection system and control practices for MRSA in DMCH should be improved in the hospital settings.

Methicillin Resistant Staphylococcus aureus in Pigs and Pig Breeders in Three Regions of Cameroon

The spread of antibiotic resistance, whether in the community or in the hospital, has recently become a major public health problem. Moreover, livestock seems to be a reservoir of resistant microorganisms such as porcine methicillin resistant Staphylococcus aureus (P-MRSA) whose carriage and transmission was mainly demonstrated in persons with occupational exposure to pigs. Much uncertainty remains about the public health implications of P-MRSA. To address concerns that exist regarding the zoonotic risk that pig carriers pose to breeders, the prevalence of P-MRSA in pigs and pig breeders was determined among 152 pig breeders in three regions of Cameroon. Materials and Method: Participants in this study came from Adamawa, Far North and Littoral regions of Cameroon. A total of 152 pig breeders or farm workers participated in this study. After having collected some social and cultural data with the aid of a questionnaire, nasal swabs were collected from pigs (n = 275) and their breeders using the standard collection procedures and placed in cooler containing cold accumulators. For each sample, microbiological assays were done as well as antibiotic susceptibility tests. Results: MRSA was isolated from 25 out of 275 pigs sampled (9.09%) and from 32 out of 152 (21.05%) pig breeders sampled;33 breeders (21.71%) were carriers of S. aureus including 32 MRSA and one MSSA. The prevalence of MRSA nasal carriage was 21.05% ± 6.48. A significant negative association between body protection and nasal carriage of MRSA (OR = 0.29, 95% CI [0.093;0.93];p = 0.04) was observed. In each region, similar strains of MRSA were isolated both in pigs and their breeders with the same antibiotic resistant profile. Conclusion: The prevalence of MRSA though not high compared to European countries warrants further research as data on this zoonosis is scarce in our context. As such, transmission of MRSA from pigs to pig breeders or vice-versa constitutes a real danger, and this relationship may be a starting point for MRSA contamination in the community. Moreover, proper use of body protections and antibiotic medications as recommended will be a better protective measure against nasal MRSA carriage.

Emergence of vancomycin-intermediate resistant Staphylococcus aureus in north of Palestine

Objective:This study was conducted to update the prevalence of methicillin-resistant Staphylococcus aureus(MRSA) isolates among human clinical S.aureus isolates recovered from Northern Palestine,to evaluate the possible presence of vancomycin-Resistant S.aureus(VRSA) and vancomycin- intermediate resistant S.aureus strains(VISA) and to determine the antimicrobial susceptibilities of these clinical isolates.Methods:The in vitro activities of 11 antibiotics against 204 non-duplicate S.aureus isolates from clinical samples in North of Palestine were determined by the diskdiffusion method.These samples were isolated between June 2006 and December 2007.The minimum inhibitory concentration (MIC) of vancomycin for 115 methicillin resistant Staphylococcus aureus(MRSA) strains was carried out using the agar dilution method.Results:One hundred and fifteen(56.4%) of these isolates were MRSA and according to their antibiotic profile these are multidrug resistant(resistant to three or more non-p-lactam antibiotics). Ninety nine(43.6%) isolates were methicillin sensitive S.aureus(MSSA),forty four of MSSA isolates(44.4%) were multidrug resistant,while forty five(45.6%) were non multidrug resistant.Our results showed that the most common resistance(95.6%) was to penicillin.Two strains of MRSA have shown to be vancomycin- intermediate resistant,had MIC of 4μg/rnL and 8μg/mL and these vancomycin- intermediate resistant S.aureus strains(VISA) are resistant to all antibiotics tested.Conclusion:According to our information this is the first study report about VISA in Palestine.

A New Epidemiological Tool for <i>Staphylococcus aureus</i>Surveillance

Epidemiological surveillance for microbes is currently based on either agar culture followed by identification, or genetic amplification. Both techniques are highly skilled-labor intensive, costly, and must be done in central laboratories. The Defined Substrate Utilization&reg;(DSU&reg;) format provides an epidemiological series of specific screening formulations that obviate these limitations. All reagents are present in optimized stable powder form in a test tube—add water, inoculate, and incubate. A specific color change provides a sensitive and specific detection of the target microbe. Two DSU&reg;methods for Staphylococcus aureus (S. aureus) are presented: aureusAlert&reg;for all S. aureus and EPI-M&reg;for methicillin-resistant S. aureus (MRSA). Both aureusAlert&reg;and EPI-M&reg;had a detection level of 20 colony forming units (CFU) in 18 hours. aureusAlert&reg;and conventional methods agreed 93.6% and EPI-M&reg;and conventional methods agreed 94.1%. DSU&reg;and conventional methods showed the same specificity.

基于真实世界研究骨髓炎MRSA感染率的Meta分析

目的:通过Meta分析研究骨髓炎患者中耐甲氧西林金黄色葡萄球菌(MRSA)的感染率。方法:检索PubMed、Web of Science、中国知网、维普、万方和中国生物医学文献数据库(CBM)关于骨髓炎患者MRSA感染率的研究,检索时限为建库至2023年8月。由2位研究人员按照纳入与排除标准对所获文献独立进行筛选、提取,采用纽卡斯尔-渥太华量表评分(NOS)进行文献质量评价。以感染率为结局指标合并数据,采用R(4.3.1)进行Meta分析,并根据骨髓炎类型、患者年龄、研究地区进行亚组分析。结果:共纳入26篇文献,共包含20860名骨髓炎患者。Meta分析结果显示,骨髓炎患者MRSA感染率为0.240(95%CI:0.183~0.297)。亚组分析结果显示,椎体骨髓炎(VO)患者、18~60岁、北美地区骨髓炎患者的MRSA感染率更高。结论:骨髓炎患者中MRSA的感染率较高,需采取有效的预防和控制措施减少MRSA的传播。

Enhanced antibacterial activity of silica nanorattles with ZnO combination nanoparticles against methicillin-resistant Staphylococcus aureus

Silica nanorattles(SNs) with zinc oxide(ZnO) combination nanoparticles are reported to inhibit methicillin-resistant Staphylococcus aureus(MRSA) for the first time. SNs loaded with ZnO nanoparticles,which can produce free radicals, can cause severe damage to bacteria. ZnO nanoparticles not only provide free radicals in the combined nanostructures, which can inhibit the growth of bacteria, but also form nanorough surfaces with an irregular distribution of spikes on the SNs, which can enhance their adhesion to bacteria. Nanorough silica shell surfaces maintain the high activity and stability of small-sized ZnO nanoparticles and gather ZnO nanoparticles together to enhance production, which improves the efficiency of free radicals against the cytomembranes of bacterial cells. The enhanced adhesion of ZnO@SN nanoparticles to MRSA cells shortens the effective touching distance between free radicals and MRSA, which also improves antibacterial activity. As we expected, the ZnO@SN nanoparticles exhibit a better antibacterial effect than free ZnO nanoparticles against MRSA in vitro and in vivo. We also demonstrate that SNs loaded with ZnO nanoparticles can accelerate wound healing in MRSA skin inflammation models. This method of multilevel functionalization will be potentially applicable to the antibacterial field.

皮肤科创面MRSA感染的临床诊断及危险因素分析

目的探讨皮肤软组织分泌物培养出耐甲氧西林金黄色葡萄球菌(MRSA)的相关疾病诊断及导致MRSA感染可能的危险因素,为皮肤科提前防控MRSA感染提供病种预警和危险因素的防治。方法回顾性分析2015年1月~2021年9月我院皮肤性病科皮肤软组织糜烂面分离培养出的MRSA。采用法国生物梅里埃公司的全自动微生物分析鉴定仪(VITEK-2 Compact)鉴定菌种。通过定义入院48小时内或48小时后获得的MRSA阳性培养,将感染分为社区获得性MRSA(CA-MRSA)或医院获得性MRSA(HA-MRSA)。结果(1)皮肤软组织MRSA感染平均占皮肤科多重耐药菌的83.19%,是主要多重耐药菌;(2)皮肤科MRSA感染主要以CA-MRSA感染为主,占71.11%(192/270)。与CA-MRSA感染相关的皮肤病依次为:天疱疮占比最高为28.12%,其次为葡萄球菌性烫伤样皮肤综合征(SSSS)16.67%和药物性皮炎6.77%(其中重症药疹2.08%)等。HA-MRSA感染最常见的也是天疱疮26.92%,其次为药物性皮炎12.82%(其中重症药疹11.54%)和脓疱性银屑病6.41%等;SSSS的CA-MRSA感染率要明显高于HA-MRSA感染(P=0.002);(3)HA-MRSA感染患者使用抗生素的比例明显高于CA-MRSA患者(P=0.001),但在糖皮质激素及免疫抑制剂系统使用上两种MRSA感染没有显著差异。结论皮肤科MRSA感染主要是社区获得性MRSA,MRSA感染最主要的疾病为天疱疮及SSSS,抗生素使用可增加院内感染MRSA的风险。

NKT细胞在MRSA感染性肺炎中作用的初步研究

目的:初步探讨NKT细胞在耐甲氧西林金葡菌(MRSA)感染性肺炎模型中的作用。方法:MRSA经鼻黏膜感染C57BL/6野生型(WT)小鼠和CD1d^(-/-)小鼠。观察小鼠生存率,检测肺组织中细菌载量,ELISA检测肺组织中细胞因子TNF-α、IFN-γ、IL-17、IL-6含量,流式细胞术检测肺组织中CD3^(+)CD8^(+)T细胞、NK细胞和NKT细胞百分比。结果:MRSA致死剂量感染5 d,WT小鼠生存率显著低于CD1d^(-/-)小鼠(46.2%vs 90.0%,P<0.05)。感染12~48 h,WT小鼠肺组织中细菌载量显著高于CD1d^(-/-)小鼠(P<0.01);WT小鼠肺组织中TNF-α、IFN-γ、IL-6和IL-17含量较CD1d^(-/-)小鼠明显增高(P<0.01)。MRSA感染24 h,WT小鼠肺组织中NKT细胞、NK细胞百分比显著高于CD1d^(-/-)小鼠(P<0.01),而CD3^(+)CD8^(+)T细胞百分比低于CD1d^(-/-)小鼠(P<0.01)。结论:在MRSA肺炎中,NKT细胞被激活,从而加重肺部炎症反应,降低生存率,减缓细菌清除。

纳米硒联合聚维酮碘对手术感染杀菌的效果

【目的】负载多功能纳米硒聚维酮碘(PVP-I@Se)消毒剂对金黄色葡萄球菌(SA)、耐甲氧西林金黄色葡萄球菌(MRSA)的杀菌效果,为皮肤手术部位消毒提供实验依据。【方法】实验分为PVP-I组(对照组)与PVPI@Se组(实验组),两组的碘浓度梯度相同,分别为50、75、100、200和400μg/mL,实验组硒浓度2μg/mL,对照组不添加硒,比较两组不同的消毒液对SA、MRSA的消毒效果,检测指标包括最低抑菌浓度(MIC)和最低杀菌浓度(MBC);碘浓度50μg/mL时的最短杀菌时间;碘浓度200μg/mL、400μg/mL时的抑菌圈大小。【结果】对照组对SA、MRSA的MIC均为79.17μg/mL、实验组分别为54.17和70.83μg/mL。而对照组对SA、MRSA的MBC分别为129.17和150.00μg/mL,实验组分别为70.83和87.50μg/mL。碘浓度50μg/mL时,对照组对SA、MRSA的最短杀菌时间为130 s、140 s,实验组分别为65 s、75 s。碘浓度200μg/mL时,对照组对SA、MRSA的抑菌圈直径分别为7.67 mm、8.33 mm,实验组均为9.50 mm。碘浓度400μg/mL时,对照组对SA、MRSA的抑菌圈直径分别为9.00 mm、9.33 mm,实验组分别为11.67 mm、12.00 mm。【结论】在聚维酮碘浓度为50、75、100、200和400μg/mL时,分别加入浓度为2μg/mL的硒,可增强其对SA、MRSA的杀菌效果、缩短作用时间。硒(SeNPs)加入PVP-I对SA、MRSA的杀菌效果均有增效作用。但增敏效果SA较MRSA显著。MRSA的增效作用对碘浓度(400μg/mL)需求较高。为临床精准选用消毒剂的浓度和作用时间,降低临床皮肤手术部位感染提供理论依据。

多重耐药MRSA耐消毒剂基因及抗生素耐药相关基因检测

目的明确浙江湖州解放军第98医院临床分离的多重耐药耐甲氧西林金黄色葡萄球菌(methicillin-resistantStaphy-lococcusaureus,MRSA)耐消毒剂基因及抗生素耐药相关基因存在状况。方法采用聚合酶链反应(PCR)技术检测20株多重耐药MRSA中耐消毒剂基因(qacA)、β-内酰胺类耐药相关基因(mecA、blaTEM)、氨基糖苷类耐药相关基因(氨基糖苷类修饰酶基因)[aac(6′)/aph(2")、aph(3′)-、ant(3")-、ant(4′,4")、ant(6)-]、四环素耐药相关基因(tetM)、红霉素耐药相关基因(erm)和万古霉素耐药相关基因(vanA、vanB)。结果20株MRSA中,qacA、mecA、blaTEM、aac(6′)/aph(2")、aph(3′)-、tetM和erm基因PCR扩增均阳性,1株ant(4′,4")基因阳性,而ant(3")-、ant(6)-、vanA和vanB4种基因均阴性。结论临床分离的多重耐药MRSA中qacA、mecA、blaTEM、aac(6′)/aph(2")、aph(3′)-、tetM和erm基因携带率均很高;在MRSA中发现qacA基因为我国首次报道,应引起医院感染监控部门高度重视。

ICU患者MRSA定植与感染的危险因素研究

目的比较重症监护室(ICU)、呼吸内科监护室(RICU)和神经外科监护室(NSICU)耐甲氧西林金黄色葡萄球菌(MRSA)定植与感染状况,探讨患者MRSA定植/感染的危险因素。方法采用前瞻性研究方法,连续收集2013年5月1日—7月31日入住某院3个ICU患者的临床资料,采集患者(医护人员)鼻拭子及其周围环境标本进行MRSA检测。结果 197例患者,检出MRSA22株,MRSA定植率为11.17%;ICU、RICU和NSICU定植率分别为4.00%、11.90%和15.87%,差别无统计学意义(χ2=4.04,P=0.133)。患者临床标本MRSA检出率为2.03%(4/197),医护人员MRSA鼻前庭定植率为1.72%(2/116)。MRSA定植患者周围环境中MRSA检出率为22.73%(5/22),高于非定植患者4.00%(7/175)(χ2=8.93,P=0.003)。多因素logistic回归分析结果显示,年龄≥60岁、侵入性操作、住ICU时间长和近期使用抗菌药物是MRSA定植/感染的独立危险因素。结论临床应主动对入住ICU的患者进行MRSA定植筛查,采取有效措施,防止MRSA在医院环境与患者间的双向传播;同时,尽量避免使用侵入性操作,减少患者住院日和合理使用抗菌药物,减少ICU患者MRSA定植与感染的发生。

社区获得性与医院获得性MRSA感染监测

目的了解社区获得性耐甲氧西林金黄色葡萄球菌（CA-MRSA）与医院获得性MRSA（HA-MRSA）的耐药特征，为临床经验性选择抗菌药物提供参考依据。方法回顾性分析某院中医外科和重症监护室（ICU）2006年1月-2008年12月临床标本中分离的MRSA菌株资料，并对2个病区分离的CA-MRSA、HA-MRSA及其耐药性进行统计分析。结果ICU分离的87株MRSA来源：痰液71株，咽拭子6株，伤口分泌物5株，血液、静脉穿刺管各2株，胸腔积液1株；其中HA-MRSA占98．85％（86／87）。中医外科的41株MRSA均分离自伤口脓液，其中CA-MRSA占48．78％（20／41），且有逐年上升趋势，由2006年的20．00％上升至2008年的71．43％（χ^2=8．24，0．01〈P〈0．025）。药敏结果显示，HA-MRSA对克林霉素（98．13％）、四环素（98．13％）、红霉素（100．00％）、环丙沙星（100．00％）、左氧氟沙星（100．00％）、庆大霉素（100．00％）的耐药率显著高于CA-MRSA（分别为42．86％、66．70％、33．33％、0．00％、0．00％、4．76％），两两比较，差异均有统计学意义（均P％0．005）。结论住院患者中CA-MRSA感染呈上升趋势。CA-MRSA与HA-MRSA的耐药性并不一致，对非β-内酰胺类抗菌药物多敏感。

脱氧核酶抑制耐药基因mecR1的表达逆转MRSA耐药性

目的探讨脱氧核酶抑制耐甲氧西林金黄色葡萄球菌(M RSA)耐药基因m ecR1的表达对M RSA耐药性的影响。方法设计、合成特异性针对耐药基因m ecR1m RNA的硫代脱氧核酶,将其导入细菌,通过半定量RTP-CR观察脱氧核酶对耐药基因m ecR1及其下游基因m ecA表达的抑制作用,并通过平板克隆形成实验观察脱氧核酶对M RSA耐药性的影响。结果加入脱氧核酶后培养的M RSA,m ecR1与m ecA的m RNA表达水平较对照组显著降低(P<0.01),在含苯唑西林(6m g L/)的M H-琼脂培养基表面生长的菌落单元数也低于对照组(P<0.01)。结论特异性抗m ecR1脱氧核酶阻断耐药基因m ecR1m-ecA的表达,可以部分恢复M RSA对抗生素的敏感性。

一株抗耐甲氧西林金黄色葡萄球菌(MRSA)的海洋放线菌的鉴定及系统发育分析

从海南三亚海域的海绵中分离到一株抗耐甲氧西林金黄色芎芍methicillin-resistant Staphylococcusaureus(MRSA)的海洋放线菌A115。该菌株在燕麦片琼脂上插片培养孢子丝螺旋形,孢子长圆形,表面有稀疏的短刺;菌株细胞壁含LL-DAP,糖型C;16S rDNA序列分析及系统发育分析表明,分离菌株A115与Streptomyces albogriseolus属同一分支,同源性为99.0％,但形态学、生理生化鉴定及活性情况存在一些差异。由此推断菌株A115为S.albogriseolus的海洋变种,命名为Streptomyces albogriseolus var.marine。

大蒜素、川穹嗪与万古霉素联用抗MRSA的作用研究

目的探讨中成药大蒜素、川穹嗪分别与万古霉素联合应用对耐甲氧西林金黄色葡萄球菌(MRSA)的体外抑制作用。方法临床分离5株MRSA,采用K-B法测定细菌对苯唑西林、头孢唑林、头孢曲松、红霉素、妥布霉素和万古霉素的敏感性;采用微量稀释法分别测定大蒜素、川穹嗪和万古霉素对MRSA的最低抑菌浓度MIC,采用棋盘稀释法测定大蒜素、川穹嗪分别与万古霉素联用时对MRSA的MIC,计算联合指数FICI。结果 5株MRSA均为多耐药菌株,仅对万古霉素敏感。大蒜素、川穹嗪对MRSA的MIC与对甲氧西林敏感的金黄色葡萄球菌(MSSA)即标准株ATCC29213的MIC比较无统计学差异。大蒜素与万古霉素在体外联合应用时,万古霉素的MIC为(0.60±0.22)μg/mL,与单用万古霉素时的MIC(2.40±0.89)μg/mL比较有统计学差异(P=0.004);川穹嗪与万古霉素在体外联合应用时,万古霉素的MIC为(0.40±0.37)μg/mL,与单用万古霉素时的MIC=(2.40±0.89)μg/mL比较有统计学差异(P=0.002)。万古霉素加大蒜素的平均FICI为0.32±0.13,呈协同作用,万古霉素加川穹嗪的平均FICI为0.65±0.09,呈相加作用。结论大蒜素、川穹嗪对MRSA有一定抑制作用。大蒜素、川穹嗪与万古霉素联合使用时具有协同或相加作用,大蒜素、川穹嗪可能成为万古霉素的增敏剂用于治疗MRSA引起的感染。

五环三萜类柴胡皂苷单体抗耐MRSA活性研究

目的对柴胡进行有效成分分离,并对其抗菌作用明确的成分进行结构测定,确定其分子结构,得到结构明确的五环三萜类活性单体Bp3(saikosaponines,Bp3)。进一步深入研究该单体的耐甲氧西林金黄色葡萄球菌(methicillin-resistant staphylococcus aureus,MRSA)作用及其与头孢唑林的协同作用。方法参照美国临床实验室标准化委员会(national committee for clinical laboratory standard,NCCLS)标准,测定Bp3对20株MRSA的MIC及其与头孢唑林的协同作用。结果Bp3对MRSA的抑菌作用优于头孢唑林且联合用药时显著减少了每一药物的最低抑菌浓度值(minimal inhibitory concentration,MIC),在20株耐甲氧西林金黄色葡萄球菌均表现为协同或相加作用方式。结论结构明确的五环三萜类单体Bp3对MRSA有一定的抑制作用,且与头孢唑林有协同或相加作用。

多重降落PCR检测血流感染产ESBLs肠杆菌科细菌与MRSA方法的建立和应用

目的探索一种可同时检测产超广谱β-内酰胺酶(ESBLs)的肠杆菌科细菌与耐甲氧西林金黄色葡萄球菌(MRSA)的多重降落PCR方法。方法收集某院20l3年3月—2014年9月102份住院患者血培养阳性标本,针对产ESBLs肠杆菌科细菌的SHV、TEM、OXA基因和MRSA的MecA基因设计4对特异性引物,分别采用单一降落PCR和多重降落PCR对各耐药基因进行扩增,并将结果与药敏纸片法进行比较。结果各单一PCR均可扩增出特异性条带,并用多重降落PCR同时检测了4种耐药基因;建立的多重降落PCR对4种耐药基因(MecA、SHV、TEM、OXA)DNA的检测下限分别为4.37、2.19、4.53和3.59 ng。与药敏纸片法相比,多重降落PCR总灵敏度与特异性分别为100.00%、88.24%,检测ESBLs的灵敏度达100.00%,特异性为87.23%,检测MRSA的灵敏度和特异度均为100.00%。结论该实验建立的多重降落PCR具有高灵敏度与特异性,可用于产ESBLs肠杆菌科细菌和MRSA所致血流感染的快速诊断与流行病学调查,有利于指导临床使用抗菌药物。

抗耐甲氧西林金黄色葡萄球菌(MRSA)卵黄免疫球蛋白(IgY)的制备与性质研究

目的观察鸡卵黄中抗耐甲氧西林金黄色葡萄球菌(methicillin-resistant staphylococcus aureus,MRSA)抗体的含量、纯度、来源及稳定性。方法用耐甲氧西林金黄色葡萄球菌(MRSA)作为抗原免疫Leghorn鸡;通过改良水稀释法提取卵黄中的IgY;双紫外光波长测定抗体含量,SDS-PAGE电泳检测抗体纯度;Western blot免疫印迹法测定该抗体来源;ELISA检测IgY对温度、酸碱度的稳定性。结果抗体含量13.3 mg/mL蛋黄液,抗体纯度达96%;免疫印迹证明IgY与鸡血清中的IgG具有相同的分子量和抗原性;IgY具有良好的热稳定性,对酸碱具有一定的耐受力。结论改良水稀释法能得到高产量、高纯度的特异性IgY,而且有良好的生物学活性。