Mec—A在慢性上颌窦炎耐甲氧西林表皮葡萄球菌中的表达与耐药性研究

目的：研究mec-A基因在慢性上颌窦炎耐甲氧西林表皮葡萄球菌（methicillin-resistant staphylococcus epidermidis,MRSE)中的表达和对常见抗生素的耐药情况。方法：采用多重聚合酶链反应（PCR）检测MRSE菌株耐药基因mec-A和金黄色葡萄球菌辅助基因fem-A表达；药敏试验采用纸片扩散法。结果：mec－A基因在MRSE菌株中的表达率97．3％（36／37），fem－A基因为金黄色葡萄菌的特有基因（100．0％表达）。MRSE菌株除对万古霉素敏感外，对其它抗生素均显示耐药。结论：多重聚合酶链反应试验能快速准确鉴定MRSE菌株；MRSE菌株对多种抗生素有耐药性。     

Mec-A在慢性上颌窦炎耐甲氧西林表皮葡萄球菌中的表达与耐药性研究

目的:研究mec-A基因在慢性上颌窦炎耐甲氧西林表皮葡萄球菌(methicillin-resistant staphylococcus epidermidis,MRSE)中的表达和对常见抗生素的耐药情况.方法:采用多重聚合酶链反应(PCR)检测MRSE菌株耐药基因mec-A和金黄色葡萄球菌辅助基因fem-A的表达;药敏试验采用纸片扩散法.结果:mec-A基因在MRSE菌株中的表达率为97.3%(36/37),fem-A基因为金黄色葡萄球菌的特有基因(100.0%表达).MRSE菌株除对万古霉素敏感外,对其它抗生素均显示耐药.结论:多重聚合酶链反应试验能快速准确鉴定MRSE菌株;MRSE菌株对多种抗生素有耐药性.     

喉癌细胞系中RASSF1A基因启动子去甲基化与基因表达的研究

目的:探讨甲基化转移酶抑制剂[5-氮杂-2′-脱氧胞苷(5-Aza-dC)]及组蛋白去乙酰化转移酶抑制剂[曲古抑菌素A (TSA)]对喉癌细胞系中抑癌基因RASSF1A甲基化水平及基因表达的影响.方法:5-Aza-dC及TSA处理体外培养的Hep-2细胞,应用Realtime PCR方法及甲基化特异性PCR(MSP)方法分别检测药物干预前后细胞中抑癌基因RASSF1A表达及甲基化情况.结果:①在Hep-2细胞中未经药物干预前抑癌基因RASSF1A表现为甲基化,抑癌基因RASSF1A弱表达.②在5-Aza-dC及TSA的作用下,Hep-2细胞系中RASSF1A基因的甲基化状态得到了逆转.其中5-Aza-dC及TSA联合应用效果与单独应用5-Aza-dC效果相似,单独应用TSA无明显效果.③在5-Aza-dC及TSA的作用下,Hep-2细胞系中RASSF1A基因表达上调,其中5-Aza-dC作用较TSA作用强,2种药物联合应用起协同增效作用.结论:喉癌细胞系中抑癌基因RASSF1A启动子甲基化可能是导致其基因失活的主要原因但并不是惟一原因.应用5-Aza-dC及TSA能够通过逆转抑癌基因RASSF1A的DNA甲基化水平和组蛋白去乙酰化水平从而使其表达得到了增强.     

气管切开术后肺部感染的病原学分析及防治

目的 归纳总结气管切开术后肺部感染的病原学特点。方法 回顾我院气管切开术后发生肺部感染的245例患者资料,对其痰细菌培养、药敏试验结果及临床资料进行分析。结果 气管切开患者发生肺部感染率为83.6%;共分离出334株病原菌,G-杆菌224株占67.1%。感染率最高的病原菌依次为:铜绿假单胞菌(23.4%)、金黄色葡萄球菌(17.4%)、克雷伯氏菌属(11.7%)、不动杆菌属(10.5%)、大肠埃希菌(9.6%)。药敏结果显示:所选抗菌药物中,对G-杆菌敏感性较高的药物有亚胺培南(73.7%),哌拉西林/他唑巴坦(61.1%), 对G+球菌敏感性较高的药物有万古霉素(100%),呋喃妥因(92．9%)。 产超广谱β 内酰胺酶的G-菌和耐甲氧西林的金黄色葡萄球菌出现的耐药率呈现上升趋势(P＜0.05)。结论 气管切开术后肺部感染主要病原菌为G-杆菌,部分细菌的耐药率明显增加,应积极开展痰细菌培养及药敏试验,合理使用抗菌药物,以减少耐药菌株的产生。     

慢性鼻窦炎耐甲氧西林葡萄球菌对抗生素的耐药分析

目的：了解慢性鼻窦炎耐甲氧西林葡萄球菌(methicillin-resistant staphylococcus, MRS)的感染情况及耐药特点,为临床合理选用抗菌药物、有效控制MRS的感染提供依据。方法：　采用苯唑青霉素纸片法和琼脂筛选法,对临床分离的葡萄球菌行MRS检测,并测定了它们对20种常用抗生素的耐药谱和β-内酰胺酶。结果：　72株金黄色葡萄球菌中,耐甲氧西林株占37.6%,其中产β-内酰胺酶菌株占77.8%。凝固酶阴性的葡萄球菌(CoN葡菌)中,耐甲氧西林株占38.3%,其中产β-内酰胺酶菌株占72.7%。MRS菌株耐药程度明显高于甲氧西林敏感葡萄球菌（P<0.05）。金黄色葡萄球菌耐甲氧西林株和凝固酶阴性葡萄球菌耐甲氧西林株多重耐药数分别为6～17种和5～15种。结论：万古霉素、利福平、丁胺卡那对MRS显示了较强的抗菌活性。万古霉素是治疗感染的首选药物,MRS的多重耐药性应引起广泛关注,需加强抗生素使用的管理和MRS对抗生素耐药性的监测。     

儿童急性中耳炎金黄色葡萄球菌抗生素耐药性与分子遗传背景特征分析

目的 分析儿童急性中耳炎分泌物中分离的金黄色葡萄球菌(staphylococcus aureus,SA)菌株抗生素药物敏感性和分子特征.方法 收集150例临床诊断为急性中耳炎儿童中耳腔脓液或耳分泌物进行细菌培养鉴定,进一步进行菌株的抗菌药物敏感性试验,检测菌株的耐药基因、毒力基因和多序列基因分型(MLST)分析.结果 ...     

PCR-GeneScan法检测遗传性聋相关基因GJB2 235 delC和mtDNA A1555G突变

目的:检测GJB2 235delC杂合突变和mtDNA A1555G突变。方法:对120例样本进行诊断试验,其中测序GJB2 235delC杂合突变样本16例,mtDNA A1555G突变17例。用PCR方法对目标片段进行扩增,PCR产物在3100DNA sequencer(ABI)上聚丙烯酰胺胶毛细管电泳,GeneScan、GeneMarker软件数据分析。结果:120例样本均得到检测结果,检出GJB2 235delC杂合突变样本17例,mtDNA A1555G突变17例,1例正常样本误诊为235delC杂合突变而出现假阳性。结论:PCR-GeneScan技术可以同时检测2种不同基因的突变,单管多重PCR和GeneScan荧光标记法结合是同时检测多种突变一种新的思路,而且可能是一种有效的方法。     

5-Aza-dC和TSA对人喉癌细胞系中CHFR基因启动子甲基化及mRNA表达水平的影响

目的:探讨5-杂氮-2′-脱氧胞苷(5-Aza-dC)和制霉菌素A(TSA)对人喉癌细胞系中CHFR基因启动子区甲基化与mRNA表达水平的影响。方法:采用荧光定量PCR技术和甲基化特异性PCR技术检测5-Aza-dC和TSA处理前后的Hep-2人喉癌细胞系基因CHFR启动子区甲基化与mRNA表达水平的变化。结果:在对照组Hep-2人喉癌细胞系中CHFR基因启动子区显示DNA甲基化,用5-Aza-dC作用后DNA甲基化程度明显减弱,mRNA表达量上调(1.75±0.21);用TSA作用后DNA甲基化程度和mRNA表达量(1.05±0.13)无明显变化。联合使用5-Aza-dC和TSA后DNA甲基化程度明显减弱,mRNA表达量明显上调(2.15±0.18)。结论:CHFR基因启动子区DNA甲基化在喉癌的发生、发展中是一个频发事件,是导致其mRNA表达下调的主要原因,5-Aza-dC单独应用和联合TSA能够逆转DNA甲基化状态,从而调控其基因表达,为临床使用药物治疗喉癌提供了新思路。     

一个遗传性耳聋大家系的基因突变检测

目的 :探讨中国人遗传性耳聋基因的突变热点和明确我们最近收集到的一个遗传性耳聋家系是否为已克隆的耳聋基因的突变所致。方法 :该家系 5代共 4 7人 ,其中耳聋患者 1 8人 ,从家系图分析 ,符合常染色体显性遗传 ;所有患者均为语后聋 ,从 1 6 3 0岁起病 ,为双耳对称性、进行性、高频听力下降为主的感觉神经性聋 ,不伴其它器官系统的异常 ;采用PCR 直接测序法在该家系中进行HDIA1、GJB3、GJB2、DFNA5、а tectorin(可导致DFNA8和DFNA1 2两型遗传性耳聋 )、MYO7A、POU4F3等 7个常染色体显性耳聋基因的突变检测。结果 :发现CX2 6基因有 2种核苷酸改变即A3 4 1G和GC2 5 7 2 5 8CG ;POU4F3基因有 1种核苷酸改变即T90C。分析后发现 ,上述核苷酸改变均不是该家系耳聋的致病性突变。其余 5个基因未发现突变。结论 :该常染色体显性耳聋家系由目前已克隆基因突变所致的可能性较小 ,笔者目前正在进行的全基因组扫描和连锁分析极有可能定位一个新的耳聋基因位点     

Methicillin resistant Staphylococcus aureus: is it a problem for nasal surgery?

Methicillin resistant Staphylococcus aureus (MRSA) is becoming ever more prevalent in the UK, and the proportion of MRSA to methicillin sensitive Staphylococcus aureus (MSSA) seems to be increasing. New strains of MRSA are ever developing resistance to antibiotic treatment, increasing morbidity and mortality of infection. Staphylococcus aureus is part of the normal flora of the nose, and MRSA colonizes the nose in infection. However, nasal surgery is rarely complicated by staphylococcal infections, and MRSA infection following nasal surgery is rare. The authors present a literature review of MRSA infection, its relation to the nasal cavity, and infection following nasal surgery.     

慢性化脓性中耳炎的病原菌及耐药性分析

目的研究慢性化脓中耳炎主要病原菌的种类及对抗生素的耐药情况。方法对162例慢性化脓 性中耳炎患者的耳分泌物进行细菌培养,对分离的病原菌进行药物敏感试验。结果分离出病原菌183株, 以金黄色葡萄球菌(63株)和铜绿假单胞菌(57株)为主,金黄色葡萄球菌对青霉素和红霉素的耐药性率分别 为100％和71.4％,对氨基糖甙类、氟喹诺酮类和头孢类抗生素敏感性较高;铜绿假单胞茵对氨苄西林、头孢 类抗生素耐药率较高,对氟喹诺酮类、氨基糖甙类抗生素敏感。结论金黄色葡萄球菌和铜绿假单胞菌是济 南地区慢性化脓性中耳炎的主要致病菌,二者对青霉素类抗生素有较高的耐药率。临床医师不能仅凭经验, 而应根据细菌培养和药敏结果用药,以防耐药菌株产生。     

Assessment of trends in antimicrobial resistance in chronic rhinosinusitis

OBJECTIVES: We performed a cross-sectional review of a prospective database to determine the contemporary incidence and temporal patterns of antimicrobial resistance in chronic rhinosinusitis (CRS). METHODS: A microbiological database was retrospectively reviewed to extract all endoscopically obtained paranasal sinus cultures from 2001 through 2005 in adult patients with CRS. The culture data were tabulated according to bacterial species and representative antibiotic resistances for methicillin, erythromycin, clindamycin, gentamicin, tetracycline, sulfamethoxazole, and levofloxacin. The data were analyzed to determine whether increasing rates of antibiotic resistance developed over the study years. Further analysis was conducted for methicillin-resistant Staphylococcus aureus (MRSA) species to determine prevalence trends and antibiotic resistance trends for MRSA versus other species. RESULTS: We analyzed 701 bacterial isolates among 392 culture samples. Staphylococcus aureus was the most commonly isolated organism (19.0%). Antibiotic resistance significantly increased for erythromycin over the study (maximum resistance rate, 69.7% in 2005; p = .009), remained unchanged for methicillin, clindamycin, levofloxacin, and sulfamethoxazole (p = .366 to p = .397), and trended downward for gentamicin (p = .180) and tetracycline (p = .120). Nineteen percent of S. aureus species were found to be MRSA, but MRSA-specific antibiotic resistance rates did not change over the course of the study (all p > or = .222). In aggregate, MRSA species exhibited statistically significant higher rates of resistance to each antibiotic tested than did non-MRSA bacteria. CONCLUSIONS: Antibiotic resistance seems to be emerging for erythromycin at a rate higher than for other antibiotics. Although not increasing in prevalence, MRSA maintains a significant presence in CRS with associated increased levels of antibiotic resistance.     

49例培养阳性的慢性鼻窦炎分泌物细菌分布及药物敏感性分析

目的探讨慢性鼻窦炎(CRS)患者鼻道黏膜分泌物细菌分布特点及药物敏感性试验,指导CRS患者抗生素的合理使用。方法鼻内镜下采集CRS鼻窦、鼻道黏膜分泌物进行细菌培养及药敏试验,均为单一细菌生长。结果培养阳性的49例标本中葡萄球菌42株,其中表皮葡萄球菌27例,占培养细菌总数的55.1%,金黄色葡萄球菌9例,占培养细菌总数的18.4%。药敏试验表明凝固酶阴性葡萄球菌对氨苄西林、苯唑西林、阿莫西林/克拉维酸、头孢曲松和环丙沙星耐药率均高达65%以上,金黄色葡萄球菌除对氨苄西林有较高的耐药率外,对其它常用的抗生素均具有较高的敏感性。葡萄球菌对大环内酯类抗生素具有较高的敏感性,未发现耐万古的葡萄球菌。结论葡萄球菌感染在CRS的致病中占有重要地位。CRS患者应进行常规细菌培养和药敏试验,抗生素的使用应以病原菌检测和药敏试验结果为基础。     

Methicillin-resistant Staphylococcus aureus otorrhea after tympanostomy tube placement

OBJECTIVE: To compare a retrospective cohort of nonhospitalized children with methicillin-resistant Staphylococcus aureus (MRSA) otorrhea with those with methicillin-sensitive S aureus (MSSA) otorrhea to determine the risk factors predisposing to MRSA otorrhea and the treatments used. DESIGN: Retrospective case-controlled series. SETTING: Tertiary pediatric care facility. PATIENTS: Seventeen children with MRSA otorrhea after bilateral myringotomy with tympanostomy tube insertion (BM&T) and 19 age- and sex-matched control subjects who demonstrated MSSA otorrhea. The average age at culture in MRSA patients was 52 months; in MSSA patients, 54 months. There were 8 boys and 3 girls in the MRSA group and 8 boys and 4 girls in the MSSA group. INTERVENTIONS: Oral, topical, and intravenous antimicrobial agents. MAIN OUTCOME MEASURES: Antibiotic exposure and history of otitis media and routine antibiotic administration (topical, oral, or intravenous). RESULTS: The following findings were statistically significant (P < or = .06, Mann-Whitney test): (1) longer duration of antibiotic treatment after BM&T for patients with MRSA vs those with MSSA; (2) increased number of episodes of acute otitis media before BM&T in patients with MRSA vs those with MSSA; and (3) increased number of courses of antibiotics after BM&T in patients with MRSA vs those with MSSA. CONCLUSIONS: Methicillin-resistant S aureus otorrhea is commonly seen as a community-acquired infection in otherwise healthy pediatric outpatients. Risk factors for development of MRSA otorrhea include the number of episodes of acute otitis media before BM&T and number of treatment courses and duration of antibiotic therapy after BM&T.     

Clinical features of head and neck cancer patients with methicillin-resistant Staphylococcus aureus

CONCLUSIONS. The risk factors for methicillin-resistant Staphylococcus aureus (MRSA) detection in head and neck cancer patients are the duration of hospitalization, intravenous hyperalimentation, prior antibiotic use, and the coexistence of other pathogens. OBJECTIVES. To shed light on the clinical characteristics of MRSA-positive inpatients with head and neck cancers. The secondary goal was to evaluate risk factors for MRSA detection in comparison with methicillin-sensitive S. aureus (MSSA). PATIENTS AND METHODS. Sixty-one consecutive inpatients with head and neck cancers with S. aureus detection were analyzed based on their medical records. The antimicrobial susceptibility of isolated S. aureus was tested by the broth microdilution method. RESULTS. MRSA and MSSA were detected in 46 (75.4%) and 15 (24.6%) of the 61 patients, respectively. There was no significant difference in the male/female ratio, age, primary site, comorbidity, cancer stage, cancer treatment, or 5-year survival rate between the MRSA and MSSA groups. Compared with the MSSA group, the MRSA group had significantly longer hospitalization periods and intervals between admission and MRSA detection, as well as significantly greater likelihood of intravenous hyperalimentation, prior antibiotic use, and co-isolation of other pathogens. Isolated strains of MRSA were thoroughly sensitive to vancomycin and arbekacin and moderately sensitive to minocycline.     

Antimicrobial resistance: current status and future direction

BACKGROUND: Antimicrobial resistance is initiated through mutations in bacterial genes, culminating in end products that help circumvent the action of specific antimicrobial agents. Resistant mutants can proliferate under a number of circumstances but primarily through the action of selective pressure from the overuse of antimicrobial agents. METHODS: The results of surveillance studies over approximately the last ten years were evaluated. CONCLUSION: Resistance rates in the group of microorganisms associated with respiratory tract infections had been increasing rapidly over the past 10 years, but, recently, many seem to have reached a plateau. However, newer, more invasive clones of methicillin resistant Staphylococcus aureus (MRSA), differing from health care-associated MRSA (HA-MRSA), and typically associated with community-acquisition (CA-MRSA), recently have begun to proliferate. Burgeoning use of fluoroquinolones has impacted the Gram-negative bacilli (e.g., Pseudomonas aeruginosa, Escherichia coli, and Salmonella), causing their resistance rates to approach the critical point. A better understanding of the epidemiology of resistance and responsible use of antimicrobial agents are mandatory if the continuing rates of increasing resistance are to be abrogated.