905株葡萄球菌的种群分布及耐药性分析

目的了解某医院2010年临床分离葡萄球菌的种群分布和耐药性。方法对该院2010年临床分离的905株葡萄球菌的种群、耐药性做回顾性分析。结果905株葡萄球菌包含11个种,其中金黄色葡萄球菌（SAU）455株,占50．28％;凝固酶阴性葡萄球菌（CNS）450株,占49．72％;临床分离葡萄球菌对抗生素耐药率可因标本来源、培养环境、种群结构、产酶与否等因素差异有统计学意义。除利奈唑胺、万古霉素和呋喃妥因敏感及四环素耐药率差异无统计学意义以外,耐甲氧西林葡萄球菌（MRS）高于甲氧西林敏感葡萄球菌（MSS）,x2值在4．30—451．0,P〈0．01或0．05,差异有统计学意义;β-内酰胺酶阳性菌高于β-内酰胺酶阴性菌,凝固酶阴性的葡萄球菌与凝固酶阳性菌对利福平、氨苄西林／舒巴坦、青霉素G、四环素、左氧氟沙星、庆大霉素的耐药率差异存在统计学意义,P〈0．05或P〈0．01;尿菌高于其他标本分离菌。各种葡萄球菌在各临床科室及标本中的分布也不尽相同。结论葡萄球菌耐药性可由多方面因素引起,临床实验室必须加强葡萄球菌分布和耐药性监测,为临床提供各种葡萄球菌诊治的依据。     

253株金黄色葡萄球菌耐药现状分析

目的 了解医院金黄色葡萄球菌临床分布情况及其对常用抗菌药物的耐药率,为临床合理使用抗菌药物提供依据.方法 回顾分析医院2010年5月至2011年4月检出的金黄色葡萄球菌,采用VITEK-AMS全自动微生物分析仪进行菌种鉴定和药敏分析.结果 共检出金黄色葡萄球菌253株,菌株的主要来源为痰130株(51.4％)、血液39株(15.4％)、创面24株(9.5％);菌株主要科室分布前3位是神内科35株(13.8％)、ICU30( 11.8％)、脑外科26株(10.3％);其中耐甲氧西林金黄色葡萄球菌( MRSA)为165株(65.2％),MRSA对多种抗菌药物耐药率＞70.0％,MSSA为88株(34.8％),对除青霉素、红霉素外的大多数抗菌药物敏感,未发现耐万古霉素菌株.结论 MRSA检出率高,耐药现状严重,应加强对金黄色葡萄球菌耐药性的监测,并根据药敏试验结果合理使用抗菌药物.     

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.     

Cloning and sequencing of the gene, fmtC, which affects oxacillin resistance in methicillin-resistant Staphylococcus aureus

Two Tn551 insertional mutants with reduced methicillin resistance were isolated from methicillin-resistant Staphylococcus aureus KSA8. These two mutants showed increased susceptibility to beta-lactam antibiotics and bacitracin, but not to fosfomycin and vancomycin. Tn551 in these mutants was inserted into the same gene, termed fmtC. The fmtC gene has an open reading frame of 840 amino acid residues with an estimated molecular mass of 96.9 kDa. The N-terminal half of the deduced FmtC protein is very hydrophobic, implying that this protein is a membrane-associated protein.     

中国传统酸肉中葡萄球菌的分离鉴定与应用研究

对我国传统酸肉中的葡萄球菌进行了首次研究,结果表明:葡萄球菌是中国传统酸肉中的重要微生物类群之一,在140个MSA培养物中有101株葡萄球菌,微球菌27株,其它杆菌和H2O2-球菌12株,所有葡萄球菌中有64%对新生霉素有抗性,属腐生葡萄球菌群及相关种群。生物培养法测定到腐生型葡萄球菌、木糖葡萄球菌和肉葡萄球菌对肌原纤维蛋白有不同程度的水解能力,可以开发成肉类专用发酵剂。     

Selective growth of Staphylococcus aureus from flushed dairy manure wastewater using acriflavine-supplemented mannitol salt agar

AIMS: To investigate the use of mannitol salt agar (MSA) supplemented with acriflavine for selective growth and quantification of Staphylococcus aureus from flushed dairy manure wastewater (FDMW). METHODS AND RESULTS: Minimal inhibitory concentrations of acriflavine in MSA were determined by comparing the growth of S. aureus subsp. aureus (ATCC 33591) and Staphylococcus epidermidis (ATCC 155) in pure culture. Acriflavine concentrations of 1.3, 1.4 and 1.5 mg l(-1) reduced CFU of S. epidermidis by 43%, 55% and 87%, respectively, while CFU of S. aureus subsp. aureus were only reduced by 15%, 20% and 26% at the respective concentrations of acriflavine. MSA supplemented with 1.5 mg l(-1) acriflavine was tested for selective growth of indigenous S. aureus from three grab samples of FDMW. Acriflavine concentrations of 1.5 mg l(-1) reduced background flora without significantly reducing (P < 0.05) indigenous S. aureus counts. CONCLUSIONS: Acriflavine-supplemented MSA provides an effective media for selective growth and quantification of indigenous S. aureus from FDMW in the presence of high levels of background microflora. SIGNIFICANCE AND IMPACT OF THE STUDY: S. aureus is implicated for mastitis infections in dairy cows. Therefore, a reliable means for monitoring and detecting the organism in FDMW provides a tool for measuring the effectiveness of treatment for reducing S. aureus levels and implementing flushwater recycling without affecting herd health.     

Cloning and expression of Staphylococcus epidermidis urease gene sequences in Staphylococcus carnosus

The urease gene sequences of Staphylococcus epidermidis CNS23 were cloned and expressed in Staphylococcus carnosus TM300. In vitro translation of the cloned sequences revealed four polypeptides (60, 17, 11 and 7.5 kDa) that were associated with enzyme activity. Southern hybridisation experiments showed high homologies with the urease genes of Staphylococcus saprophyticus.     

Evidence for importance of the Staphylococcus hyicus lipase pro-peptide in lipase secretion, stability and activity

Abstract To investigate the function of the pro-peptide (PP) region of the Staphylococcus hyicus exolipase, restriction sites were created in the lipase gene to facilitate the construction of deletions in this region. Lipase gene expression was carried out in Staphylococcus carnosus . In the presence of the entire PP region, the 86-kDa pro-lipase was efficiently exported, had high lipolytic activity, and hardly any degradation products were seen in Western blot analysis. In addition to the 86-kDa pro-lipase, the membrane fraction contained a 106-kDa immunoreactive form. If the PP was completely or partially deleted, signal peptide processing, lipase secretion, lipase activity and/or lipase stability were impaired. The results obtained with lipase PP deletion mutants indicate that the PP region may have two functional domains. The N-terminal region of the lipase PP appears to be more important for lipase activity and the C-terminal portion for lipase secretion and proteolytic stability. In the presence of only the C-terminal part of the PP lipase, secretion was hardly affected. However, the activity of the extracellular lipase was markedly reduced. If only a small portion of the C-terminal part of the PP was present, lipase secretion was again markedly reduced and no lipase activity was detectable. In the presence of the N-terminal half of the PP region, lipase secretion was affected to a lesser extent. However, the resulting 60-kDa form, which showed comparably good specific lipase activity, suffered severe proteolytic degradation.     

Identification of a fmtA-like gene that has similarity to other PBPs and beta-lactamases in Staphylococcus aureus

We identified a gene from Staphylococcus aureus, flp (fmtA-like protein), encoding a protein of 489 amino acid residues with a molecular mass of 56.4 kDa. The deduced amino acid sequence shows similarity to previously characterized penicillin binding proteins (PBPs) and FmtA of S. aureus (one of the factors which affect methicillin resistance). FLP protein has three motifs, which are conserved in PBPs and beta-lactamases, suggesting that it might be associated with cell wall synthesis. Recombinant FLP protein, however, lacks penicillin binding activity, and the inactivation of flp in two methicillin-resistant S. aureus strains did not cause a reduction in the methicillin resistance.     

Activity of the major staphylococcal autolysin Atl

The major autolysin of Staphylococcus aureus (AtlA) and of Staphylococcus epidermidis (AtlE) are well-studied enzymes. Here we created an atlA deletion mutant in S. aureus that formed large cell clusters and was biofilm-negative. In electron micrographs, the mutant cells were distinguished by rough outer cell surface. The mutant could be complemented using the atlE gene from S. epidermidis. To study the role of the repetitive sequences of atlE, we expressed in Escherichia coli the amidase domain encoded by the gene, carrying no repeat regions (amiE) or two repeat regions (amiE-R1,2), or the three repeat regions alone (R1,2,3) as N-terminal His-tag fusion proteins. Only slight differences in the cell wall lytic activity between AmiE and AmiE-R1,2 were observed. The repetitive sequences exhibit a good binding affinity to isolated peptidoglycan and might contribute to the targeting of the amidase to the substrate. AmiE and AmiE-R1,2 have a broad substrate specificity as shown by similar activities with peptidoglycan lacking wall teichoic acid, O-acetylation, or both. As the amidase activity of AtlA and AtlE has not been proved biochemically, we used purified AmiE-R1,2 to determine the exact peptidoglycan cleavage site. We provide the first evidence that the amidase indeed cleaves the amide bond between N-acetyl muramic acid and L-alanine.     

医院工作人员鼻腔葡萄球菌带菌状况年度推移的调查报告

本文报道1989年从202名医院工作人员鼻腔分离葡萄球菌的带菌状况和药敏性检测结果。并将此结果同作者等于1985年对200名同类人员检测的结果相比较,作了年度推移的调查分析发现1989年度的总带菌率(76.6％)比1985年度(84.5％)略有下降,但其中的金黄色葡萄球菌带菌率却从1985年的7.5％上升为10.4％。从1989年和1985两个年度的调查中,均发现临床科室人员金葡菌带菌率高于其它辅助科室人员,说明医务人员带菌率与接触病人成正相关关系。分离菌株对12种抗菌药物的耐药性检测结果显示,1989年分离菌株对其中9种的敏感性下降,并且从耐药谱显示出对5种抗菌药物耐药的多重耐药菌株明显增多。另从金葡菌的耐药情况,也看出1989年的耐药率高于1985年菌株。还在1989年分离的金葡菌中出现25％的耐甲氧西林菌株。     

Using fusions with luxAB from Vibrio harveyi MAV to quantify induction and catabolite repression of the xyl operon in Staphylococcus carnosus TM300

Abstract The luxA,B genes from the Gram-negative marine bacterium Vibrio harveyi MAV were used in Staphylococcus carnosus TM300 as a reporter system for regulated expression of xylose utilization. The luciferase genes were fused to the xyl operon from Staphylococcus xylosus C2a. Expression of bioluminescence was induced through addition of xylose and repressed in the presence of glucose. A method to quantitate bioluminescence directly from the culture is described.     

A novel application of Fourier-transformed infrared spectroscopy: classification of slime from staphylococci

Abstract

It has been proposed that the virulence of nosocomial Staphylococcus infections associated with indwelling medical devices is related to the ability of the bacterium to colonise these materials by forming a biofilm composed of multilayered cell clusters embedded in a slime matrix. However, the pathogenic role of exopolysaccharide biofilms is not fully understood. A new method was sought for differentiating the structure of slime from two closely related bacterial strains, Staphylococcus aureus and Staphylococcus epidermidis. Using PCR it was confirmed that these strains were positive for the icaA and icaD genes and the complete ica operon (2.7 kb). Monosaccharide analysis by thin-layer chromatography revealed an identical profile for both strains, with xylose and glucose present among the four visible bands. Using Fourier-transformed infrared spectroscopy and hierarchical cluster analysis, three of four S. aureus samples (75%), and four of five S. epidermidis samples were grouped according to species. A novel FTIR approach in classifying slime produced by S. aureus and S. epidermidis is reported.     

Investigation of a choline phosphate synthesis pathway in Streptococcus pneumoniae: evidence for choline phosphate cytidylyltransferase activity

Abstract The antimicrobial peptide epidermin is distinguished by thioether amino acids such as mso -lanthionine, 3-methyllanthionine, and 2-aminovinylcysteine. The enzyme EpiB, encoded on a plasmid of the producing strain Staphylococcus epidermidis Tü3298, is very likely involved in the formation of these unusual amino acids. In order to obtain high-level production of EpiB, an improved staphylococcal expression vector based on the xylose-inducible xylA promoter of Staphylococcus xylosus was constructed. As shown by the expression of a lipase reporter gene, the new plasmid pTX15 mediated a considerably higher expression level after induction and a lower background expression level in the uninduced state than the previously described vector pCX15. The epiB gene was inserted in pTX15 and expressed in Staphylococcus carnosus . The EpiB protein was detected both in the cytoplasmic and the membrane fraction and was partially purified in three steps.     

Coagulase‐negative staphylococci as reservoirs of genes facilitating MRSA infection

Recent research has suggested that Staphylococcus epidermidis is a reservoir of genes that, after horizontal transfer, facilitate the potential of Staphylococcus aureus to colonize, survive during infection, or resist antibiotic treatment, traits that are notably manifest in methicillin‐resistant S. aureus (MRSA). S. aureus is a dangerous human pathogen and notorious for acquiring antibiotic resistance. MRSA in particular is one of the most frequent causes of morbidity and death in hospitalized patients. S. aureus is an extremely versatile pathogen with a multitude of mechanisms to cause disease and circumvent immune defenses. In contrast, most other staphylococci, such as S. epidermidis, are commonly benign commensals and only occasionally cause disease. Recent findings highlight the key importance of efforts to better understand how genes of staphylococci other than S. aureus contribute to survival in the human host, how they are transferred to S. aureus, and why this exchange appears to be uni‐directional.     

ICU耐甲氧西林金黄色葡萄球菌的基因检测与感染控制

目的:研究耐甲氧西林金黄色葡萄球菌(MRSA)SCCmec基因分型情况并对其耐药谱进行分析。方法:收集临床标本522例,应用多重PCR法对MRSA进行SCCmec基因分型,采用全自动微生物鉴定药敏分析仪进行细菌的鉴定及药敏试验,部分药敏试验采用K-B法。结果:522例中分离出146例MRSA,其中10株为SCCmec I型(6.84%),29株为SCCmec II型(19.86%),103株为SCCmecⅢ型(70.55%),未分型4株(2.74%)。MRSA分离株对奎奴普汀/达福普汀、替考拉宁、复方磺胺甲恶唑、万古霉素和利奈唑胺敏感,SCC mecII型与SCC mecIII型对氯霉素的耐药率分别为27.59%和11.65%,对利福平的耐药率分别为13.79%和2.91%,存在明显的差异性(P0.05),其余均呈高水平耐药。146例MRSA患者中治愈52例,占35.62%;感染相关死亡者12例,占8.22%。结论:ICU耐甲氧西林金黄色葡萄球菌的基因检测以SCC mecIII型为主,且对抗菌药物呈多药耐药。