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。

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.

Molecular typing of methicillin and vancomycin-resistant Staphylococcus aureus isolated from clinical specimens by double locus sequence typing(DLST)method

Methicillin-resistant Staphylococcus aureus(MRSA)strains are the essential cause of infections in communities and hospitals.The present study was conducted to determine the molecular typing of MRSA,isolated from hospitalized patients,using the double-locus sequence typing(DLST).In total,280 S.aureus isolated from clinical specimens by phenotypic(catalase,coagulase,DNase,oxacillin,vancomycin screening agar and antibiotic disk diffusion),and molecular methods(PCR for determining the mecA,vanA and nuc genes).The DLST and sequencing was performed for MRSA containing mecA.Out of 280 specimens,confirmed as Staphylococcus aureus(S.aureus),123(43.9%)strains were MRSA.The highest resistance toward the erythromycin(15μg),followed by ciprofloxacin(5μg),clindamycin(2μg),tetracycline(30μg),gentamicin(10μg)and rifampicin(5μg),was 98.3%,97.5%,94.3%,90.2%,83.7%and 41.4%,respectively.Also,the least resistance(0%)was observed in each of teicoplanin(30μg),linzolide(30μg),and vancomycin(30μg).All(100%)of MRSA strains had the mecA,and none of them have had the vanA.The results of DLST showed that the most common sequence types were BPH 2003 and 0217.The DLST type 18-32 was a significant cluster of MRSA.By sequencing MRSA and comparing the dominant types via the DLST,it is possible to establish the etiology of the disease in a much shorter time,and prevent the complications of the disease.Therefore,the combination of partial sequences of clfB and spa can serve as useful genetic markers for MRSA typing.It concluded that the MRSA in our region was relatively high,but no vancomycin resistance was found.The majority of the MRSA DLST type was 18–32.

Molecular Epidemiology of Oxacillin-resistant Staphylococcus aureus and in vitro Activity of Glycopeptides against Staphylococcus species

The purpose of this subject was to investigate molecular epidemiology of oxacillin-resistant Staphylococcus aureus (MRSA) isolated from hospitalized patients, and to survey the in vitro activity of teicoplanin, vancomycin and other 9 antibiotics against Staphylococcus species . MRSA were detected by oxacillin-NaCl-containing screen agar. The homology of nosocomial MRSA from ICU and RCU was determined by pulse-field gel electrophoresis. Agar diffusion, E test and agar dilution were used to compare the in vitro activity of teicoplanin and vancomycin against Staphylococcus spp from 2001 to 2003 at Peking Union Medical College Hospital. WHONET-5.3 software was used to analyze the antimicrobial susceptibility data. From 2001 to 2003, the prevalences of MRSA were 56.5%, 65.3%, 64.7%, respectively. PFGE found most of MRSA from ICU and RCU were closely related. All of S.aureus and S.epidimidis isolates were susceptible to teicoplanin and vancomycin from 2001 to 2003. However, 1 isolate of S.haemolyticus was resistant and 9 isolates intermediate to teicoplanin. The minimal inhibitory concentration of teicoplanin did not correlate well with zone diameter, when inoculum increased by 100 folds, the zone diameters of teicoplanin decreased more greatly than those of vancomycin. In 2002, severe outbreaks caused by MRSA strains had been found in ICU and RCU wards. Teicoplanin and vancomycin had good activity against clinical isolates of Staphylococci spp . Teicoplanin was less active than vancomycin against S.haemolyticus . Most of S.haemolyticus isolates were intermediate to teicoplanin. Antimicrobial susceptibility testing of teicoplanin was influenced by the diffusion speed in the agar and inoculum size.

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.

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.

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.

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。

A report on infection dynamics of inducible clindamycin resistance of Staphylococcus aureus isolated from a teaching hospital in India

Objective:To investigate the infection of hospital-and community-acquired"erythromycininduced clindamycin resistant"strains or D-test positives of clinical isolates of Staphylococcus aureus(S.aureus)(with and without methicillin resistance)in a hospital.Methods:Strains of S.aureus isolated from clinical specimens were subjected to D-test and antibiotic profiling.Results:Of the total 278 isolates,140(50.35%)were D-test positives and the rest were D-test negatives.Further,of 140(100%)pesitives,87(62.14%)and 53(37.85%)strains were from males and females,respectively.Of 140(100%)pesitives,117(83.57%)were methicillin resistant S.aureus and23(16.42%)were methicillin sensitive S.aureus;of 140 strains,103(73.57%)strains front persons with and 37(26.42%)were without related infections;of 140 strains,91(65%)and 49(35%)were from hospital-and community-acquired samples,respectively.In 140 strains,118(84.28%)with comorbidities and 22(15.71%)without comorbidities cases were recorded;similarly,persons with prior antibiotic uses contributed 108(77.14%)and without 32(22.85%)positive strains.These binary data of surveillance were analyzed by a univariate analysis.It was evident that the prior antibiotic uses and comorbidities due to other ailments were the determinative factors in D-test positivity,corroborated by low P values,P=0.001 1 and 0.0024,respectively.All isolates(278)were resistant to17 antibiotics of nine groups,in varying degrees;the minimum of 28%resistance for vancomycin and the maximum of 97%resistance for gentamicin were recorded.Further,of 278 strains,only42(15.1%)strains were resistant constitutively to both antibiotics,erythromycin resistant and clindamycin resistant,while 45(16.2%)strains were constitutively sensitive to both antibiotics(erythromycin sensitive,and clindamycin sensitive).Further,of the rest 191(68.7%)strains were with erythromycin resistant and clindamycin resistant,of which only 140(50.35%)strains were D-test positives,while the rest 51(18.34%)strains were D-test negatives.Conclusions:In view of high prevalence of D-test positive S.aureus strains,and equally high prevalence of multidrug resistant strains both in community and hospital sectors,undertaking of D-test may be routinely conducted for suppurative infections.

Determining of antibiotic resistance profile in Staphylococcus aureus isolates

Objective:To determine the pattern of antibiotic resistance among Staphylococcus aureus(S. aureus) isolates from clinical specimens and to identify community-acquired methicillin-resistant Staphylococcus aureus(CA-MRSA) in specimens that have been collected from patients referring to one of the hospitals of Ahvaz.Methods:S.aureus isolates from a hospital in Ahvaz were screened for resistance to various antibiotics including methicillin.The susceptibility of the isolates was determined by Kirby-Bauer disc diffusion method.The MRSA was also treated with ethidium bromide to find the origin of resistance.Results:Among the bacterial isolates,all of 11 S.aureus were resistant to methicillin and cefixime,2 were resistant to ciprofloxacin,6 were resistant to tetracycline and the reminder were sensitive or intermediate to other antibiotics.The treated isolates were reminded resistant to methicillin and this suggested that the plasmid was not the origin of resistance in these isolates.Conclusions:These results showed that infection due to MRSA is widespread in Ahvaz and with respect to the spread of vancomycin resistance among MRSA and appearance of overwhelming infections.It is necessary to identify continuously the profile of antibiotic resistance among S.aureus isolates in other regions and finding appropriate antibiotic for infection control and eradication.

Antibiotics Susceptibility Profile of Staphylococcus aureus Clinical Isolates Collected in Hospitals in the City of Douala (Cameroon)

Introduction: Staphylococcus aureus is one of the most important agents involved in community and hospital-acquired infections. Due to the multi-drug resistance of strains to antibiotics, treatment to eradicate it is becoming more difficult and poses a global public health problem. Methodology: This was a cross-sectional study conducted from March to August 2020 in hospitals in the city of Douala, including all S. aureus isolates from diagnostic samples. Strain identification and antibiotic susceptibility testing were performed using the Vitek2 CompactTM (BioMerieux). Results: During the study period, 136 non-repetitive S. aureus strains were identified with a high frequency of methicillin-resistant S. aureus of 78.7%. The majority of the strains originated from the Douala General Hospital (66.9%) and was most frequently isolated from blood culture samples (55.1%). The study of biochemical characteristics showed that most of the strains identified had between 87% and 99% homology with the reference strain. The most active antibiotics were Quinupristin/Dalfopristin (94.2%), Linezolid (87.8%) and Vancomycin (84.2%). Methicillin resistance was associated with decreased susceptibility of S. aureus to other antibiotics such as Gentamycin (44.9%), Erythromycin (38.2%), Tetracycline (38.3%), Trimethoprim (21.4%), Ciprofloxacin (19.1%) and Levofloxacin (24.0%). Inducible MLSb and constitutive resistance phenotypes were identified with 26.7% and 22.8% respectively. Conclusion: The sensitivity of S. aureus strains differs from one antibiotic family to another, and remains good for molecules that are not available in our context. The high frequency of Methicillin-Resistant S. aureus shows the continuous progression of multi-resistant strains of S. aureus and their decreased sensitivity to usual antibiotics becomes more and more alarming.

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。

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.

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。

牛源MRSA新疆流行株的分离鉴定及spa基因多态性分型

【目的】明确新疆地区牛源耐甲氧西林金黄色葡萄球菌(MRSA)流行株的流行特点,为有效防控新疆奶牛乳房炎和子宫内膜炎提供参考依据。【方法】采用分离培养、生化鉴定、药敏试验等方法对牛源MRSA进行鉴定,并以PCR扩增牛源MRSA新疆流行株spa基因的X区,测序结果列提交至spa分型数据库(http://www.ridom.de/spaserver/)进行spa基因多态性分型。【结果】从221份样品中共检测出71株金黄色葡萄球菌,其中对苯唑西林抑菌直径小于10mm的有8株;而以mec A引物进行PCR扩增,发现扩增结果呈阳性的有13株,MRSA检出率为18.3%。spa基因分型有4种,分别为t779、t2883、t13751和t1939,其中5株为t779(r08),4株为t2883(r07-r23-r21-r17-r34),2株为t13751(r07-r23-r12-r21-r17-r12),2株为t1939(r07-r23-r02-r34),即t779(r08)为MRSA新疆流行株的主要spa基因分型。【结论】MRSA在新疆不同地区均有分布,且其耐药情况不断变化,以t779(r08)为MRSA新疆流行株的主要spa基因分型。

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。