2008-2010年舟山某院金黄色葡萄球菌的分布及耐药性变迁

目的 分析舟山医院三年来金黄色葡萄球菌分布及耐药性变迁,并对耐甲氧西林金黄色葡萄球菌(MRSA)与甲氧西林敏感金黄色葡萄球菌(MSSA)的耐药性差异做对比.方法 用ATB Expression半自动微生物分析仪进行菌株鉴定及药敏试验,用K-B法测红霉素、克林霉素、头孢西丁、苯唑西林直径,比较耐甲氧西林金黄色葡萄球菌(MRSA)与甲氧西林敏感金黄色葡萄球菌(MSSA)的耐药性差异.结果 金黄色葡萄球菌对苯唑西林、庆大霉素、红霉素、四环素和克林霉素的耐药率有上升的趋势;MRSA对苯唑西林、庆大霉素、复方新诺明、克林霉素、红霉素、青霉素、喹奴普汀-达福普汀、利福平和四环素的耐药率都明显高于MSSA的耐药率,二者间差异有统计学意义(P＜0.01),D-试验阳性71株,占72.45％.结论 金黄色葡萄球菌的耐药性逐渐升高,特别是对MRSA应引起临床的重视,检测克林霉素诱导型耐药具有重要的临床应用价值.     

临床分离金黄色葡萄球菌药物敏感性及其生物膜形成能力的研究CSCD

目的 初步探讨临床分离金黄色葡萄球菌药物敏感性与其生物膜形成的关系。方法 收集2020年1月至2022年1月大同市第二人民医院检验科临床送检的痰液、尿液、血液和伤口分泌物等样本。采用VITEK-2全自动微生物菌株鉴定系统分离出非重复致病性金黄色葡萄球菌60株;采用刚果红试验定性鉴定产膜菌株和非产膜菌株;采用VITEK-2全自动微生物药敏试验系统进行药敏分析;采用96微孔板试验半定量鉴定菌株产膜能力。结果 通过VITEK-2全自动微生物菌株鉴定系统检出耐甲氧西林金黄色葡萄球菌(MRSA)32例(53.3%),甲氧西林敏感型金黄色葡萄球菌(MSSA)28例(46.7%)。生物膜阳性菌30株(50.0%),生物膜阴性菌30株(50.0%)。其中,MRSA菌株产膜率53.1%,MSSA菌株产膜率46.4%,二者差异无统计学意义(P>0.05)。96微孔板试验筛选出强产膜菌株7株(23.3%),弱产膜菌株23株(76.7%)。强产膜菌株中,MRSA菌株6株,占85.7%,耐药5种以上占71.4%;弱产膜菌株中,MRSA菌株11株,占47.8%,耐药5种以上占26.1%;30株生物膜阴性菌,耐药5种以上占26.7%。结论 本研究临床分离的金黄色葡萄球菌中,MRSA菌株产膜能力强于MSSA菌株,产膜菌株耐药种类高于非产膜菌株。     

葡萄球菌耐药性的监测分析

目的：研究葡萄球菌的感染及耐药性状况,指导临床合理用药。方法：常规方法及阳光微生物鉴定仪鉴定菌株。药敏试验用革兰阳性需氧球菌药敏检测卡,检测耐甲氧西林金黄色葡萄球菌（MRSA）和耐甲氧西林凝固酶阴性葡萄球菌（MRCNS）,金黄色葡萄球菌（SA）和凝固酶阴性葡萄球菌（CNS）对12种抗生素的耐药率。结果：158株葡萄球菌中,MRSA占47.5%（78/158）,MRCNS占21.5%(34/158),SA占70.9%（112/158）,CNS占29.1%(46/158)。耐甲氧西林葡萄球菌（MRS）对12种抗生素的耐药率均高于甲氧西林敏感葡萄球菌（MSSA）。结论：MRSA的耐药性较高,需加强其抗生素的耐药性检测。     

MRSA中mecA及femB基因的检测与耐药相关性

研究femB、mecA基因在耐甲氧西林金黄色葡萄球菌(MRSA)中的表达与耐药的关系.运用PCR对MRSA的femB、mecA基因进行检测,MRSA耐药检测采用头孢西丁纸片法.40 株金黄色葡萄球菌(下简称金葡菌)通过头孢西丁纸片法,检出 30 株耐头孢西丁的菌株,通过PCR检测这 40 株金葡菌mecA基因,30 株MRSA全部为阳性, femB基因在 30 株MRSA中全部表达,而甲氧西林敏感的金黄色葡萄球菌(MSSA)的未表达.结果可见,PCR能快速准确地鉴定MRSA, mecA基因是MRSA的耐药基因,femB基因是MRSA的耐药相关基因.     

芜湖地区生牛奶中金黄色葡萄球菌的污染状况及其耐药性和毒力基因检测

目的明晰芜湖地区生牛乳中金黄色葡萄球菌的污染状况及其耐药性和产毒性,为该地区防治奶牛乳房炎提供理论依据。方法分别使用国标GB 4789.10-2010方法和PCR方法对从芜湖地区4个奶牛场采集的185份生牛乳进行金黄色葡萄球菌和耐甲氧西林金黄色葡萄球菌(MRSA)分离鉴定;采用纸片扩散法检测甲氧西林敏感金黄色葡萄球菌分离株(MSSA)和MRSA分离株的耐药性,PCR方法检测其携带毒力基因情况。结果共检出金黄色葡萄球菌49株,总检出率为26.5%(49/185),4个奶牛场的检出率分别为19.4%(A场)、14.0%(B场)、57.1%(C场)和14.0%(D场)。金黄色葡萄球菌分离株中MRSA阳性率为28.6%(14/49),MRSA的总检出率为7.6%(14/185),4个奶牛场的检出率分别为13.9%(A场)、4.0%(B场)、14.3%(C场)和0.0%(D场)。MSSA分离株对青霉素、阿莫西林、克林霉素、磺胺甲唑/甲氧苄啶、恩诺沙星、红霉素、庆大霉素和头孢噻肟的耐药率分别为97.1%、88.6%、80.0%、77.1%、25.7%、22.9%、11.4%和2.9%,多重耐药率为88.6%。MRSA分离株对12种药物的耐药率大小依次为青霉素、阿莫西林、苯唑西林、克林霉素和磺胺甲唑/甲氧苄啶(100.0%)、红霉素(78.6%)、头孢噻肟(71.4%)、恩诺沙星(64.3%)、庆大霉素(21.4%)、四环素(14.3%)、氯霉素和利福平(7.1%),多重耐药率为100.0%。MSSA和MRSA分离株携带毒力基因nuc、cal、hla、sea、clfA和fnbA的检出率分别为100.0%和100.0%、100.0%和100.0%、91.4%和85.7%、77.1%和85.7%、77.1%和78.6%、91.4%和78.6%,优势毒力基因型为nuc-hla-sea-calclfA-fnbA。结论芜湖地区生牛奶中存在金黄色葡萄球菌污染,污染状况存在牛场差异性。MSSA和MRSA分离株均具有产毒性,且后者的耐药和多重耐药性较前者严重。     

重症监护病房金黄色葡萄球菌耐药性与流行病学分析

为了解重症监护病房感染金黄色葡萄球菌的耐药性及流行状况,收集重症监护病房2007年9～12月临床分离的金黄色萄萄球菌42株,纸片扩散法检测其对10种抗生素的耐药率,随机引物扩增PCR(Ran- dom amplified polymorphic DNA,RAPD)检测其流行状况。42株金黄色葡萄球菌对氨苄西林的耐药率最高,没有检测到对万古霉素耐药的金黄色葡萄球菌。35株金黄色葡萄球菌为耐甲氧西林的金黄色葡萄球菌(MR- SA),7株为甲氧西林敏感的葡萄球菌(MSSA),除万古霉素外,MRSA对其他9种抗生素的耐药率比MSSA高,42株金黄色葡萄球菌经RAPD分型分为5个基因型,其中Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ型分别占31.0%、38.1%、14.3%、9.5%、7.1%。重症监护病房临床金黄色葡萄球菌分离株对多种抗生素具有高耐药性,其感染基因型以Ⅰ、Ⅱ型为主。     

社区感染金黄色葡萄球菌临床分离株耐药谱研究

目的研究社区获得性金黄色葡萄球菌耐药情况。方法采用常规方法分离金黄色葡萄球菌,用全自动微生物分析仪进行菌种鉴定和药敏试验,采用苯唑西林纸片扩散法检测耐甲氧西林金黄色葡萄球菌(MRSA)。结果社区感染的金黄色葡萄球菌主要分离自精液和尿液,MRSA的分离率为22.0%。MRSA对青霉素和环丙沙星的耐药率均为100%。所有的分离株对呋喃妥因和万古霉素均敏感。MRSA对红霉素、庆大霉素、四环素、复方新诺明、氯霉素和头孢克罗的耐药率分别为92.6%、33.3%、67.7%、92.6%、82.1%和75.1%。MSSA对上述药物的耐药率为75.6%、32.3%、50.5%、7.1%、25.3%和4.5%。结论社区感染的金黄色葡萄球菌主要为甲氧西林敏感的金黄色葡萄球菌,社区感染的MRSA的耐药性较为严重,而MSSA除青霉素和红霉素外耐药率较低。万古霉素对MRSA的体外抗菌活性非常强。     

深圳市金黄色葡萄球菌耐药性分析及分子分型

目的了解深圳市金黄色葡萄球菌的耐药性特点及分子分型特征。方法收集2012年来自深圳市7所医院的428株金黄色葡萄球菌,以琼脂稀释法测定其对12种抗菌药物的最低抑菌浓度(MIC),采用聚合酶链式反应(PCR)检测杀白细胞毒素(PVL),并对携带PVL基因的菌株进行多位点基因序列分型(MLST)。结果428株金黄色葡萄球菌中耐甲氧西林金黄色葡萄球菌(MRSA)共116株(26.2%),甲氧西林敏感金黄色葡萄球菌(MSSA)共312株(73.8%)。在12种抗菌药物中,该菌对青霉素和红霉素的耐药率最高,分别为88.8%和44.2%;未发现替考拉宁、利奈唑胺和万古霉素的耐药株。MRSA对青霉素和环丙沙星的耐药率显著高于MSSA。428株金黄色葡萄球菌中,有60株(14.02%)携带PVL基因。MLST分型结果显示共有14种已知序列型和4种新的序列型,其中ST59和ST338最多,分别为16株和12株。结论深圳地区金黄色葡萄球菌MRSA检出率以及对多种抗菌药物的耐药率均低于全国平均水平,PVL基因阳性率处于中等水平;存在多种ST分型,以ST59和ST338多见,具有遗传多样性和独特的遗传背景。     

西安市MRSA 耐消毒剂基因qacA/B 的检测

目的:了解西安市三甲综合医院耐甲氧西林金黄色葡萄球菌(MRSA)qacA/B基因的携带情况,以便掌握其对消毒剂的耐药情况。方法:收集临床分离的152株耐甲氧西林金黄色葡萄球菌,采用聚合酶链反应检测qacA/B基因,并将qacA/B基因扩增产物进行测序,测序结果进行比对。结果:152株耐甲氧西林金黄色葡萄球菌中有11株检出qacA/B阳性,qacA/B携带率7.2%;测序结果比对发现,4株qacA的基因编码序列同一位点均有一个碱基发生突变(C→T),苏氨酸突变为异亮氨酸。结论:该地区临床分离的耐甲氧西林金黄色葡萄球菌中qacA/B携带率相对较低,但也存在抵抗消毒剂的风险,临床应加强消毒剂使用的管理,阻止MRSA的传播,减少感染的发生。     

耐甲氧西林葡萄球菌和肠球菌blaTEM及tetM基因检测

目的了解临床分离的耐甲氧西林葡萄球菌(MRS)和肠球菌中blaTEM及tetM基因存在状况。方法分离50株耐甲氧西林金黄色葡萄球菌(MRSA),7株耐甲氧西林表皮葡萄球菌(MRSE)、5株耐甲氧西林溶血葡萄球菌(MRSH)、15株粪肠球菌和9株屎肠球菌,采用PCR技术检测耐药基因。结果MRSA、MRSE、MRSH、粪肠球菌和屎肠球菌中blaTEM基因阳性率分别为40.0%、57.1%、60.0%、6.7%和88.9%,tetM基因阳性率分别为100%、0%、0%、66.7%、0%。结论blaTEM基因阳性率在MRS中较高,在屎肠球菌中则很高;携带tetM基因是MRSA和粪肠球菌对四环素耐药的主要原因。     

Comparison of methods for the detection of methicillin resistance in Staphylococcus aureus isolates from food products

AIMS: To compare several methods for detection of methicillin resistance in Staphylococcus aureus isolates from food. METHODS AND RESULTS: Two hundred S. aureus isolates from food of animal origin were screened for methicillin resistance by a PCR assay specific for the mecA gene, an oxacillin agar screen test and a cefoxitin disk diffusion test. Six out of 200 strains (3%) were found to be methicillin-resistant Staphylococcus aureus (MRSA) by PCR. The oxacillin agar screen test detected only one of the MRSA isolates (sensitivity of 16.7%) and mischaracterized three additional strains as MRSA (specificity of 98.45%). None of the MRSA strains was detected by the cefoxitin test (sensitivity of 0%), while 15 methicillin-susceptible S. aureus (MSSA) strains were misclassified as resistant (specificity of 92.3%). Fifteen MSSA strains displayed a beta-lactamase hyperproducer-like phenotype. The six MRSA (mecA-positive) strains resembled the characteristics of heteroresistant strains. CONCLUSIONS: As MRSA of animal origin may display atypical phenotypes, PCR appears to be more reliable for detection of methicillin resistance in animal strains. SIGNIFICANCE AND IMPACT OF THE STUDY: The study stresses the need for implementing the methods of screening S. aureus from food of animal origin for methicillin resistance.     

Reduced susceptibility to triclosan in methicillin-resistant Staphylococcus aureus

Susceptibility to triclosan in Staphylococcus aureus was determined. The study was carried out on 200 strains, including 100 resistant (MRSA) and 100 susceptibile (MSSA) to methicillin. The examined strains were isolated from varied clinical samples and patients in 18 medical centers, in majority from hospitals in the region of Gdansk. The susceptibility was estimated by the MIC (minimal inhibitory concentration) using dilution test in Mueller-Hinton agar. The antimicrobial resistance patterns were determined, including resistance to methicillin and mupirocin. The most of MRSA strains (62%) demonstrated reduced susceptibility to triclosan (MIC 2mg/L), while 93% of MSSA strains were highly sensitive to this antibacterial agent (MIC 0,031mg/L). The majority (66,1%) of MRSA strains with reduced susceptibility to triclosan demonstrated the same antimicrobial resistance pattern. Reduced susceptibility to triclosan was observed in 8 from 9 high - level mupirocin resistant strains, but the most of MRSA strains with reduced triclosan susceptibility (91,5%) were found among fusidic acid resistant strains.     

Sensitivity of methicillin-resistant Staphylococcus aureus strains to some antibiotics, antiseptics and disinfectants

The effects of antibiotics, antiseptics and disinfectants against some methicillin resistant (MRSA) and methicillin-sensitive (MSSA) Staphylococcus aureus strains have been studied. The MRSA and MSSA strains were equally sensitive to phenols, esters of para(4)-hydroxybenzoit acid and chlorhexidine but MRSA strains were slightly more resistant to quaternary ammonium compounds and considerably more so to dibromopropamidine isothionate. Some MRSA strains were also resistant to phenylmercuric nitrate (but not another organomercurial, thiomersal), mercuric chloride and cadmium chloride. All MRSA strains produced β-lactamase. Strains from the Royal Free Hospital, London were highly resistant to β-lactam antibiotics, erythromycin, trimethoprim and tetracyctines but were sensitive to other antibiotics. One strain from the University Hospital of Wales, Cardiff was resistant to gentamicin but sensitive to tetracycline and trimethoprim.     

Detection and identification of methicillin resistant and sensitive strains of Staphylococcus aureus using tandem measurements

Discrimination of methicillin resistant (MRSA) and sensitive (MSSA) strains of Staphylococcus aureus, was achieved by the specially selected lytic bacteriophage with a wide host range of S. aureus strains and a penicillin-binding protein (PBP 2a) specific antibody. A quartz crystal microbalance with dissipation monitoring (QCM-D) was employed to analyze bacteria-phage interactions. The lytic phages were transformed into phage spheroids by exposure to water-chloroform interface. Phage spheroid monolayers were transferred onto QCM-D sensors by Langmuir-Blodgett (LB) technique. Biosensors were tested in the flow mode with bacterial water suspensions, while collecting frequency and energy dissipation changes. Bacteria-spheroid interactions resulted in decreased resonance frequency and an increase in dissipation energy for both MRSA and MSSA strains. Following the bacterial binding, these sensors were further exposed to a flow of the penicillin-binding protein (PBP 2a) specific antibody conjugated latex beads. Sensors tested with MRSA responded to PBP 2a antibody beads; while sensors examined with MSSA gave no response. This experimental difference establishes an unambiguous discrimination between methicillin resistant and sensitive S. aureus strains. Both free and immobilized bacteriophages strongly inhibit bacterial growth on solid/air interfaces and in water suspensions. After lytic phages are transformed into spheroids, they retain their strong lytic activity and demonstrate high bacterial capture efficiency. The phage and phage spheroids can be used for screening and disinfection of antibiotic resistant bacteria. Other applications may include use on biosensors, bacteriophage therapy, and antimicrobial surfaces.     

Nasal carriage of methicillin resistant Staphylococcus aureus and their antibiotic susceptibility patterns in children attending day-care centers

Nasal colonization with community acquired methicillin resistant Staphylococcus aureus (CA-MRSA) is being increasingly reported, especially in places where people are in close contact and in reduced hygiene, such as day-care centers. In this study we investigated the frequency of MRSA colonization and their antibiotic susceptibility patterns in 1-6 years old children of day-care centers in Hamadan, West of Iran.Five hundred nasal swabs were collected from children of 27 day-care centers that had no risk factors for colonization by S. aureus. The specimens were cultured for isolation of S. aureus by standard methods. Antimicrobial susceptibility testing was performed according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. For evaluation of the frequency of erythromycin induced clindamycin resistance, disk approximation test (D-test) was applied.Totally, 148 (29.6%) children were colonized by S. aureus. Out of 260 male, 94 (36.2%) and of 240 female, 54 (22.5%) cases were nasal carriers of S. aureus (P value = 0.001). Six (4.1%) of the 148 S. aureus isolated from children were MRSA strains. None of MRSA and methicillin susceptible S. aureus (MSSA) was resistant to vancomycin and clindamycin. Three of the 6 strains of MRSA and 7 (4.9%) of the 142 MSSA strains were resistant to erythromycin, and D-test was positive in all of them.We conclude that the rate of colonization by S. aureus is high in children attending day-care centers but colonization with MRSA is not common in our areas. Clindamycin or trimethoprim-sulfamethoxazol could be used in mild to moderataly severe diseases caused by CA-MRSA. However, if the CA-MRSA isolates are erythromycin resistant, D-test should be carried out for detection of inducible clindamycin resistance.     

区级医院重症监护病区耐甲氧西林金黄色葡萄球菌的调查和分析

目的通过对区级医院重症监护病区耐甲氧西林金黄色葡萄球菌(MRSA)感染的流行初期进行调查和分析,以防止MRSA的暴发流行以及能够采取有效治疗措施。方法对2006年12月至2007年1月区级医院重症监护病区患者、医务人员及物体上送检标本中被MRSA感染的病例进行调查和分析。结果从重症监护病区患者、工作人员及物体上采集标本MRSA的感染阳性率分别为25%~47.6%、0%和20%。结论此次有局部暴发趋势的MRSA感染由于发现及时、措施得当被控制住。医院必须加强监督抗生素的合理用药和耐药性的检测,严格医务人员洗手及实行消毒隔离措施,切断传播途径,防止MRSA感染在医院的发生和流行。     

Sensitivity of methicillin-resistant Staphylococcus aureus strains to some antibiotics, antiseptics and disinfectants

The effects of antibiotics, antiseptics and disinfectants against some methicillin-resistant (MRSA) and methicillin-sensitive (MSSA) Staphylococcus aureus strains have been studied. The MRSA and MSSA strains were equally sensitive to phenols, esters of para(4)-hydroxybenzoic acid and chlorhexidine but MRSA strains were slightly more resistant to quaternary ammonium compounds and considerably more so to dibromopropamidine isothionate. Some MRSA strains were also resistant to phenylmercuric nitrate (but not another organomercurial, thiomersal), mercuric chloride and cadmium chloride. All MRSA strains produced beta-lactamase. Strains from the Royal Free Hospital, London were highly resistant to beta-lactam antibiotics, erythromycin, trimethoprim and tetracyclines but were sensitive to other antibiotics. One strain from the University Hospital of Wales, Cardiff was resistant to gentamicin but sensitive to tetracycline and trimethoprim.     

Resistance to gentamicin and related aminoglycosides in Staphylococcus aureus isolated in Brazil

Isolates of Staphylococcus aureus obtained from a Brazilian university hospital were characterized in relation to resistance to gentamicin and related aminoglycosides. Thirty-six isolates were susceptible to methicillin (MSSA) and 14 were resistant (MRSA). All isolates were sensitive to nucleic acid-binding compounds. All MRSA isolates and one MSSA isolate were demonstrated to be resistant to gentamicin and were coincidentally resistant to amikacin, kanamycin, neomycin and tobramycin. Among the gentamicin sensitive MSSA isolates, five isolates were found to be resistant only to kanamycin/neomycin. The resistance to gentamicin (and related aminoglycosides: kanamycin and tobramycin) must be due to AAC(6')-APH(2") activity. As these isolates also showed resistance to neomycin, they must carry an additional genetic element, probably the one responsible for APH(3')III activity, which accounts for the high level of resistance to kanamycin and to amikacin. The resistance to kanamycin/neomycin in the gentamicin sensitive isolates could not be attributed to the AAD(4')(4") activity because of the tobramycin sensitivity, and so could be ascribed to the APH(3')III activity. Curing and transfer experiments, as well as electrophoresis procedures, indicate that gentamicin resistance in Staph. aureus strains here studied has, characteristically, chromosomal localization.