葡萄球菌和肠球菌耐药监测

目的 调查分析四川省人民医院1 779株葡萄球菌和肠球菌分布及其对常用抗菌药物的耐药性.方法 采用VITEK全自动细菌鉴定仪及纸片扩散法(K-B法)进行鉴定及药物敏感性分析.结果 金黄色葡萄球菌中耐甲氧西林金黄色葡萄球菌(MRSA)检出率占54.3％,未发现对万古霉素、替考拉宁和利奈唑胺的耐药株;肠球菌属中,屎肠球菌和粪肠球菌均已出现对利奈唑胺和替考拉宁耐药的菌株.结论 四川省人民医院葡萄球菌和肠球菌中金黄色葡萄球菌对万古霉素、替考拉宁和利奈唑胺均敏感,但葡萄球菌和肠球菌耐药性需加强监测,并采取有效控制措施.     

脓毒症金黄色葡萄球菌感染监测及治疗体会

目的分析常见抗菌药物敏感性及对确诊金黄色葡萄球菌感染脓毒症患者目标性治疗情况。方法收集兰州军区兰州总医院2009年1—3月送检血液标本及2010年1—3月送检的多种标本(血液、痰、支气管肺泡灌洗液等)。筛选送检的阳性标本中2次或2次以上培养出同一种金黄色葡萄球菌的脓毒症患者72例,记录用药情况,病情转归。结果 2010年1—3月共收集各种微生物标本3153份,检出阳性标本1108份,分离出细菌和真菌1557株,其中金黄色葡萄球菌106株(6.81%),耐甲氧西林金黄色葡萄球菌(MRSA)61株,占金黄色葡萄球菌的57.55%;2009年及2010年血液标本中金黄色葡萄球菌检出率分别为8.33%和10.71%。MRSA对万古霉素、利奈唑胺敏感性相当,对万古霉素耐药率为4.92%。对确诊金黄色葡萄球菌感染患者进行目标性治疗,临床疗效较好。结论金黄色葡萄球菌是脓毒症患者重要致病菌之一,耐药率较高,2010年同期检出率高于2009年,利奈唑胺是治疗耐药金黄色葡萄球菌感染的良好选择。     

我院细菌耐药性监测与抗菌药物敏感性分析

［摘要］　目的　了解该院细菌对抗菌药物的敏感性,指导临床抗菌药物合理应用。方法　监测该院2012年临床分离菌株的耐药性,以美国临床和实验室标准协会（CLSI）推荐的纸片扩散法测定其抗菌药物敏感性,用WHONET5.3软件分析结果。结果　按照监测方案,共获得780株细菌对抗菌药物敏感性结果,其中革兰阳性菌239株,占30.6%;革兰阴性菌541株,占69.4%。除绿脓杆菌外,所有革兰阴性杆菌对碳青霉烯类药物敏感率均在85.7%以上,哌拉西林他唑巴坦79.6%以上;所有葡萄球菌对万古霉素100.0%敏感,耐甲氧西林金黄色葡萄球菌（MRSA）检出率为51.1%,MRSA对氯霉素的敏感率为80.0%,对其他药物均较耐药;屎肠球菌和粪肠球菌对万古霉素和利奈唑胺最敏感(96.6%,100.0%;100.0%,100.0%)。结论　肺炎克雷伯菌、大肠埃希菌、鲍曼不动杆菌、肠杆菌属对碳青霉烯类敏感率较高,但铜绿假单胞菌对其耐药率较高。葡萄球菌属对万古霉素、利奈唑胺、替考拉宁敏感率均较高。     

2009年中国12家教学医院革兰阳性球菌耐药性研究

目的 调查2009年我国革兰阳性球菌临床分离株的耐药性.方法 收集2009年6-12月9个城市12家教学医院临床分离的1169株非重复革兰阳性球菌.采用琼脂稀释法测定抗菌药物的最低抑菌浓度(MIC)值.结果 金黄色葡萄球菌和凝固酶阴性葡萄球菌中耐苯唑西林菌株分别占45.3%(211/466)和89.5%(214/239);不同标本苯唑西林耐药金黄色葡萄球菌(MRSA)分离率为33.3%～68.1%.未发现对替考拉宁、万古霉素和利奈唑胺耐药的葡萄球菌.5.5%(7/128)的屎肠球菌对万古霉素耐药,未发现万古霉素耐药的粪肠球菌;粪肠球菌和屎肠球菌对利奈唑胺的敏感率约为99.1%(108/109).肺炎链球菌中青霉素中介株(P1SP)分离率为21.6%(48/222),仅发现1株青霉素耐药株(PRSP),占0.5%(1/222);未发现对替考拉宁、万古霉素和利奈唑胺耐药的肺炎链球菌.结论 葡萄球菌中苯唑西林耐药菌株仍有较高的分离率,不同标本类型MRSA的分离率有所不同.替考拉宁、万古霉素和利奈唑胺对葡萄球菌、粪肠球菌、屎肠球菌和肺炎链球菌具有很好的抗菌活性.     

利奈唑胺在临床治疗中的药代动力学和药效学

 唑烷酮类抗菌药物是继磺胺类和喹诺酮类药物之后,第三类全合成抗菌药物。利奈唑胺是第一个也是目前惟一获准应用于临床的唑烷酮类抗菌药物。自2000年首先在美国上市以来,利奈唑胺已经在全世界70多个国家应用于超过400万例严重的革兰阳性（G⁺）菌感染患者^［1］。利奈唑胺的作用机制新颖,对G⁺菌的抗菌谱广,与其他抗菌药物间无交叉耐药性。体内外研究证实,该药对葡萄球菌属、链球菌属、肠球菌属等G⁺菌,包括多重耐药菌如甲氧西林耐药的金黄色葡萄球菌（MRSA）、耐药肺炎链球菌（DRSP）和万古霉素耐药的肠球菌（VRE）等具有较强的抗菌活性,与万古霉素作用相似或更优。本综述将主要阐述利奈唑胺的药代动力学/药效学（PK/PD）研究及其在临床治疗中的意义。     

利奈唑胺治疗耐甲氧西林金黄色葡萄球菌感染重症肺炎的疗效观察

<正>近年来,耐甲氧西林金黄色葡萄球菌(MRSA)感染肺炎在医院重症感染性肺炎中占首位〔1〕。传统应用万古霉素治疗MRSA感染肺炎的疗效确切,但药物不良反应(ADR)时有发生,限制其在临床上的广泛应用。利奈唑胺是第1个上市的恶唑烷酮类合成抗生素,可用于治疗MRSA引起的感染。目前,国外对万古霉素与利奈唑胺治疗MRSA感染疗效比较已有文献报道〔2〕,本文拟比较利奈唑胺和万古霉素治疗MRSA感染肺     

呼吸道耐甲氧西林金黄色葡萄球菌耐药临床分析

目的了解呼吸道耐甲氧西林金黄色葡萄球菌(MRSA)感染现状及耐药性。方法选择2010-11～2011-10门诊及住院患者呼吸道标本培养的263株金黄色葡萄球菌进行分析。结果 MRSA分离率为57.79%(152/263),药敏显示MRSA对万古霉素及利奈唑胺敏感,对复方新诺明及利福平保持一定敏感性,对β-内酰胺类、喹诺酮类、大环内酯类、氨基糖苷类耐药率在80%以上。结论呼吸道MRSA多重耐药情况严重,应首选万古霉素或利奈唑胺。     

利奈唑胺在革兰阳性球菌肺炎中的临床应用

 革兰阳性（G⁺）球菌是医院和社区获得性肺炎的重要病原菌。以往认为,医院获得性G⁺菌肺炎以金黄色葡萄球菌（以下简称金葡菌）为主,而社区获得性G⁺菌肺炎以肺炎链球菌为主。然而,近年来随着全球抗菌药物的广泛应用,耐药G⁺球菌日益增多,尤其是甲氧西林耐药的金葡菌（MRSA）已成为医院获得性肺炎的重要致病菌之一,其在社区获得性肺炎中的比例也在不断上升^［1-2］。特别是在院内呼吸机相关性肺炎患者分离的金葡菌中, MRSA检出率可达40%～70%^［3］。而在亚洲8个国家和地区进行的一项调查显示,医院获得性MRSA和社区获得性MRSA的检出率分别为67.4%和25.5%^［4］。由于MRSA对多种抗菌药物耐药,医院获得性MRSA肺炎和社区获得性MRSA肺炎住院时间延长,治疗费用增加,且预后不佳,因此早期合理的经验性抗菌治疗显得尤为重要。长期以来,糖肽类的万古霉素一直是治疗MRSA感染的主要抗菌药物,但随着使用时间的延长和应用范围拓宽,糖肽类药物的最低抑菌浓度（MIC）值向上爬升。虽然目前万古霉素耐药的金葡菌（VRSA）较少,但万古霉素中介的金葡菌（VISA）、异质性万古霉素中介的金葡菌（hVISA）等的不断出现,仍然给临床MRSA肺炎治疗带来了新的挑战。     

葡萄球菌对利奈唑胺的耐药机制及其流行病学

葡萄球菌包括金黄色葡萄球菌(SA)和凝固酶阴性的葡萄球菌属(CoNS),是临床上最常见、最重要的革兰阳性球菌之一.万古霉素及替考拉宁是针对耐甲氧西林的SA(M RSA)、耐甲氧西林的CoNS(MRCoNS)感染的一线抗菌药物,但随着MRSA MIC值的漂移、异质性万古霉素中介的SA(hVISA,指万古霉素MIC值为1～2 mg/L,但其中不到10-6的菌株为能在万古霉素浓度＞2 mg/L的培养基中生长的MRSA菌株,与万古霉素治疗反应差、MRSA感染患者预后不佳密切相关)、万古霉素中介的SA乃至万古霉素耐药的SA的出现,美国感染病学会推荐利奈唑胺、达托霉素及替加环素等用于这类感染的抗菌治疗[1-2].     

烧伤患者创面感染金黄色葡萄球菌分离株耐药性及流行病学分析

目的对河北地区烧伤患者创面分离的120株金黄色葡萄球菌进行mecA和SCCmec检测分析MRSA耐药机制,为临床合理用药提供依据。方法在2009~2013年收治的烧伤患者创面中分离的120株金黄色葡萄球菌,采用头孢西丁纸片法进行MRSA筛选,对mecA基因,SCCmec和spa基因进行PCR扩增以及分型。结果 120株金黄色葡萄球菌中有74株为MRSA,占61.7%。药敏试验显示,MRSA对16种临床常见抗生素耐药率,超过85%的有7种,依次为苯唑西林（98.6%）,青霉素（96.0%）,环丙沙星（94.6%）,阿莫西林和头孢唑林（89.2%）,亚胺培南（87.8%）,庆大霉素（85.1%）,另有1株对万古霉素耐药。结论本组金黄色葡萄球菌MRSA检出率较高,并表现出较高的耐药性。MRSA具有的多重耐药性mecA基因密切关系。     

Ventriculitis due to a hetero strain of vancomycin intermediate Staphylococcus aureus (hVISA): successful treatment with linezolid in combination with intraventricular vancomycin

A 67-year male presented with relapse 14 days after treatment with vancomycin for a MRSA ventriculitis. CSF samples taken at the time of relapse grew MRSA with a MIC for vancomycin of 4 mg/L by E-test and therapy with linezolid (600 mg bd) and intraventricular vancomycin (20 mg od) was initiated. Using the macrodilution E-test, the isolate was found to have sub-populations with a MIC for vancomycin of 8 mg/L and teicoplanin of 12 mg/L and a population analysis profile almost identical to the hVISA strain MU3, indicative of a hVISA strain. Concentrations of vancomycin in the CSF over the period of therapy ranged from 25.6-192.5 mg/L after intraventricular administration and those of linezolid ranged from 3.4-6.7 mg/L after intravenous administration, exceeding the MICs for this isolate. The patient made a successful recovery, with no further episodes of ventriculitis at 1-year follow-up. We report the first case of ventriculitis due to hVISA. It was successfully treated with intrathecal vancomycin and intravenous linezolid. We also believe this to be the first documented case of clinical infection due to hVISA in South Africa.     

Treatment considerations for recurrent MRSA bacteremia leading to cholecystitis

We present an end-stage renal disease patient with acute cholecystitis caused by a recurrence of methicillin-resistant Staphylococcus aureus (MRSA) bacteremia. Timely antibiotic therapy with vancomycin did not eradicate the patient’s infection. In this patient, the minimum inhibitory concentration (MIC) of the organism for vancomycin was at the upper limit of susceptibility. The ability to thoroughly understand and interpret mean inhibitory concentrations is crucial in antibiotic selection. For high-risk patients with Staphylococcus aureus infection with reduced susceptibility to vancomycin as demonstrated by an MIC of 2 mg/L or greater, we suggest further investigation into linezolid as an alternative antibiotic to vancomycin therapy. Compared to vancomycin, linezolid has similar effectiveness in patients with MRSA bacteremia as well as improved penetration, particularly in bile.     

Vancomycin-resistant Staphylococcus aureus: a real and present danger?

The glycopeptide antibiotic, vancomycin and teicoplanin, are the mainstay of therapy for infections involving strains of Staphylococcus aureus that are resistant to methicillin and gentamicin. During the last 5 years, clinical isolates of S. aureus showing reduced susceptibility to glycopeptides have been reported from many countries around the world, often associated with prolonged glycopeptide therapy. Detection and monitoring of such strains has been hindered by the fact that vancomycin (or glycopeptide)-intermediate S. aureus (VISA) isolates may be missed on conventional disk sensitivity tests. Effective control measures are required to prevent the increasing occurrence and spread of such strains in both the hospital and community settings. An important aspect of control is promoting the judicious use of glycopeptides. The recent introduction of the alternative antibiotics quinupristin/dalfopristin and linezolid, which are active against S. aureus strains resistant to many other classes of agent, should facilitate this process. Received: November 14, 2001 · Revision accepted: February 16, 2001     

Vascular graft infection by Staphylococcus aureus: efficacy of linezolid,teicoplanin and vancomycin systemic prophylaxis protocols in a rat model

Objective

We investigated experimentally the in vivo prophylactic efficacies of linezolid, teicoplanin and vancomycin in subcutaneously implanted dacron graft infection caused by methicillin-resistant Staphylococcus aureus (MRSA).

Materials and methods

Dacron grafts (1 cm²) were aseptically implanted into subcutaneous pockets that were surgically prepared in the backs of 50 rats. Ten of these rats were used as the control group (group I). Grafts in the remaining 40 rats were infected by inoculation of MRSA at the concentration of 2 × 10⁷ colony-forming units (CFU)/ml. Ten of these rats constituted the contaminated, untreated group II. The other three study groups comprising 10 rats each were contaminated and then treated with linezolid (group III), teicoplanin (group IV) and vancomycin (group V), respectively. All rats were sacrificed and the grafts were removed after seven days and evaluated.

Results

The bacterial count decreased in the rats from the groups treated with linezolid, teicoplanin and vancomycin. The linezolid and teicoplanin groups, however, showed a significantly lower bacterial number than the vancomycin group (p = 0.009 and p = 0.01). The intensity of inflammation was highest in the contaminated, untreated group, as expected.

Conclusions

Single-dose linezolid, teicoplanin and vancomycin for peri-operative prophylaxis may prevent bacterial growth in vascular graft infections. The effect of linezolid and teicoplanin seemed similar and their effect was greater than that of vancomycin.     

Epidemiology and Clinical Impact of Glycopeptide Resistance in <Emphasis Type="Italic">Staphylococcus aureus</Emphasis>

Abstract Staphylococcus aureus with resistance to glycopeptide antibiotics has been considered to be a rare cause of clinically relevant infections. A review of the current literature shows that this is indeed the case for infections caused by S. aureus with high-level resistance to vancomycin (VRSA), as only isolated cases have been reported. VRSA develops following the insertion of the vanA gene, which is transferred from enterococci with vancomycin resistance. On the other hand, infections caused by S. aureus with intermediate resistance to glycopeptides (VISA), or heterogeneously expressed intermediate level glycopeptide resistance (hVISA), are more common. These infections are associated with clinical failure of glycopeptide therapy. While the biochemical and phenotypic features including a thickened cell wall of hVISA and VISA are well known, the genetic basis of these phenotypes remains unknown. Certain genetic regulatory elements such as agr II are associated with reduced susceptibility of S. aureus to glycopeptides. Available data suggest that certain infections might be successfully treated using higher doses of vancomycin. However, as treatment failure is particularly common in infections with a high bacterial load, it may be necessary to resort to other antibiotics such as linezolid, often combined with surgical intervention, in order to successfully treat these infections. Open questions regarding diagnosis, pathogenesis, epidemiology, and treatment of glycopeptide resistance in S. aureus are addressed in this review. Clinicians should be aware of these aspects, since S. aureus remains one of the most important bacteria in modern medicine.     

Daptomycin and vancomycin non-susceptible methicillin-resistant Staphylococcus aureus clonal lineages from bloodstream infection in a Brazilian teaching hospital

IntroductionThis study aimed to characterize Staphylococcus aureus isolates from bloodstream infections in patients attending a teaching hospital, between 2011 and 2015.MethodsThe minimum inhibitory concentration for daptomycin, linezolid, oxacillin, teicoplanin, vancomycin, and trimethoprim/sulfamethoxazole was accessed by broth microdilution. SCCmec type and clonal profile were determined by molecular tests. Vancomycin heteroresistance was evaluated using screening tests and by population analysis profile/area under the curve.ResultsAmong 200 S. aureus isolates, 55 (27.5%) were MRSA, carrying SCCmec II (45.5%) or IV (54.5%). The most frequent MRSA lineages were USA100 (ST5-II) (45.5%) and USA800 (ST5-IV) (30.9%). Six isolates were confirmed as vancomycin heteroresistant, showing area under the curve ratio 1.1, 1.2 or 1.3 (four USA100, one USA800 and one USA1100 isolates).ConclusionsDaptomycin and vancomycin non-susceptible MRSA clonal lineages were found in bloodstream infections over five years, highlighting the importance of continuous surveillance of multiresistant bacteria in hospitals.     

Detection of heterogeneous, intermediate-vancomycin-resistant Staphylococcus aureus (hVISA) using low-concentration vancomycin disks

Heterogeneous, intermediate-vancomycin-resistant Staphylococcus aureus (hVISA) represents a threat of an incurable infection since the first report in 1997. The method used to detect hVISA isolates is a population analysis profile (PAP); however, it is impractical for routine laboratory analysis. We therefore tested a simple, reliable and inexpensive method for the detection of hVISA. Eighteen isolates of hVISA and 22 of vancomycin-sensitive S. aureus (VSSA) were included. The organisms were tested by the disk diffusion method, using 15-microg vancomycin disks on four different media: Mueller-Hinton agar (MHA), MHA plus 2% NaCI (MHAS), Brain Heart Infusion agar (BHA), and BHA plus 2% NaCl (BHAS). In addition, two different inoculum sizes, bacterial suspensions adjusted to 0.5 and 2.0 McFarland, were tested. The inhibition zone was read independently by three medical technologists after incubation at 37 degrees C for 24 and 48 hours. The use of MHAS with an inoculum size of 2.0 McFarland and 48-hour incubation period yielded the highest sensitivity (94.4%), specificity (81.8%), positive predictive value (80.9%), and negative predictive value (94.7%). The disk diffusion test with 15-microg vancomycin disk is simple and may be used as a screening method for the detection of hVISA.     

达托霉素对2679株革兰阳性球菌外抗菌活性的研究

目的 研究达托霉素等抗菌药物对2679株革兰阳球菌的体外抗菌活性.方法 收集2010年1月-2011年12月9个城市17家教学医院临床分离的2679株非重复革兰阳性球菌.采用微量肉汤稀释法测定的达托霉素最低抑菌浓度(MIC),用琼脂稀释法测定其他抗菌药物的MIC值,用WHONET5.6软件进行药敏数据统计分析.结果 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(MRSCoN)检出率分别为45.8％和84.2％,MRSA对复方磺胺甲(噁)唑和氯霉素的敏感率分别为93.1％和85.5％,对红霉素、四环素、克林霉素和利福平的敏感率分别为13.8％、26.6％、63.2％、50.0％,对达托霉素、万古霉素和利奈唑胺的敏感率均为100.0％,MRSCoN对达托霉素、万古霉素和利奈唑胺的敏感率均为100.0％,达托霉素对于MRSA和MRSCoN的MIC50和MIC90均为0.5 mg/L.513株肠球菌对于高水平庆大霉素耐药率为56.9％,氯霉素和四环素的敏感率分别为76.0％和44.1％,对替加环素和达托霉素敏感率均达100.0％,达托霉素对于其中17株耐万古霉素肠球菌(V RE)的MIC50和MIC90均为2 mg/L.肺炎链球菌和β-溶血链球菌对于达托霉素的敏感率均为100.0％,按口服青霉素折点判读,青霉素不敏感的肺炎链球菌(PNSSP)的比例为63.1％.达托霉素对于PNSSP的MIC50和MIC90分别是0.125 mg/L和0.25 mg/L.达托霉素对于β-溶血链球菌MIC50和MIC90分别是0.008 mg/L和0.032 mg/L.结论 达托霉素对临床常见革兰阳性球菌具有较好的抗菌活性,包括多重耐药菌,是治疗革兰阳性菌特别是耐药菌感染的很好选择.     

78例耐甲氧西林葡萄球菌感染临床分析及其对预后的影响

目的 了解耐甲氧西林葡萄球菌（MRS）的感染状况及其对患者住院天数、医疗费用和病死率的影响,为MRS感染的临床治疗提供依据.方法 对78例MRS和50例甲氧西林敏感葡萄球菌（MSS）感染的患者进行回顾性分析.结果 发生院内MRS感染的65例患者中,64例有长期使用抗生素史.感染的部位主要为下呼吸道和手术切口,分别为43.6%和25.6%,培养的MRS以耐甲氧西林金黄色葡萄球菌比例最高（53.8%）.MRS感染患者的住院时间、医疗费用、病死率均显著性长于和高于MSS感染者（P＜0.05）.MRS对万古霉素和利奈唑胺的敏感性最高,未发现耐药者,其次为替考拉宁,敏感率为98.6%.结论 MRS感染以下呼吸道和手术切口为主,合理使用抗生素对MRS感染的预防至关重要.发生感染时,万古霉素和利奈唑胺为其最佳选择的抗菌药物.     

Changing microbiological profile and antimicrobial susceptibility of the isolates obtained from patients with infective endocarditis – The time to relook into the therapeutic guidelines

The microbiological profile, associated risk factors and demographic characteristics of patients with IE has changed in the recent times. In the present study, the antibiotic susceptibility profile of 66 isolates (40 from IDU and 26 from non IDU) recovered over a period of three years from the patients with definitive diagnosis of IE along with their absolute minimum inhibitory concentrations (MIC-μg/ml) was determined as per CLSI, 2017 guidelines. Staphylococcus aureus was found to be the predominant pathogen associated with IE out of which 90.2% isolates were MRSA, although none of the isolates were found resistant to vancomycin, teicoplanin, daptomycin and linezolid. Pseudomonas aeruginosa isolates were 100% susceptible to carbapenams, however variable resistance was observed against other antimicrobials. All Enterococci were found to be 100% susceptible to linezolid and daptomycin, whereas vancomycin resistant enterococci phenotype was observed in 25% of the Enterococcal isolates. A noticeable difference in the antimicrobial susceptibility profile and their MICs were observed in the present study, as compared to published literature across the globe and within the country. However, no statistically significant difference (λ ² test, p > 0.01)in the AST pattern of isolates from IDU vs. Non IDU was observed. After reviewing the local antibiogram it seems that we need to have our own regional guidelines, which may partially replace the currently prevailing AHA/ESC guidelines.