抗耐药革兰阳性菌药物研究进展

近年耐药革兰阳性菌感染有增多趋势,如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）感染,近期报道的个别耐万古霉素金黄色葡萄球菌（VISA或GISA）及异质性耐万古霉素葡萄球菌（vancomycin hetero—resistance staphylococci）、耐万古霉索肠球菌（VRE）及耐青霉素肺炎链球菌（PRSP）感染等,引起了医药界关注,本文将简要介绍近年研究开发的抗耐药革兰阳性菌药物,供临床参考。     

去甲万古霉素治疗耐甲氧西林金黄色葡萄球菌 医院获得性肺炎的临床疗效

目的 观察去甲万古霉素治疗耐甲氧西林金黄色葡萄球菌（MRSA）医院获得性肺炎的临床疗效。方法 选择2013年8月~2018年10月我院收治的MRSA医院获得性肺炎患者68例,随机分为观察组（37例）和对照组（31例）。观察组给予去甲万古霉素治疗,对照组给予利奈唑胺治疗,比较两组临床疗效、细菌学转归及不良反应情况。结果 观察组总有效率为86.49%,低于对照组的70.27%,但差异无统计学意义（P＞0.05）。观察组细菌总清除率为70.27%,低于对照组的70.97%,但差异无统计学意义（P＞0.05）。观察组不良反应发生率为29.73%,高于对照组的25.81%,但差异无统计学意义（P＞0.05）。结论 对于MRSA医院获得性肺炎的治疗,去甲万古霉素疗效和安全性与利奈唑胺相似。     

某医院2013年金黄色葡萄球菌的耐药性及感染现状分析

目的：了解我院2013年金黄色葡萄球菌(Staphylococcus aureus,SAU)的感染现状及耐药性,为临床合理应用抗菌药物提供依据。方法收集分离我院2013年住院及门诊患者送检的SAU菌株共549株,并对其感染现状及耐药性进行分析。结果2013年共分离SAU共549株,占所有分离细菌的比例为8.6%,其中耐甲氧西林金黄色葡萄球菌(Methicil in resistant Staphylococcus aureus,MRSA)326株,在SAU中所占比例为59.4%。药敏结果显示,2013年我院SAU对青霉素的耐药率为96.1%,对万古霉素、替考拉宁及呋喃妥因的敏感性好,而对头孢唑林、氨苄西林-舒巴坦及红霉素等的耐药率均大于30%。326株MRSA菌株来自临床各个标本,如痰液、创面分泌物及脓液等,其中在痰液中检出菌株最多,占52.4%,其次为创面分泌物,占25.5%。临床科室中分离出MRSA最多的科室是重症监护室,占19.9%,其次是骨科、烧伤科和儿科,分别为14.1%、12.9%和12.6%。结论 MRSA的检出率高,临床上需要采取综合措施预防和控制MRSA感染。     

汕头大学医学院附属第一医院耐甲氧西林金黄色葡萄球菌(MRSA)耐药谱分析

目的:了解汕头大学医学院附属第一医院分离的92株耐甲氧西林金黄色葡萄球菌(MRSA)的耐药情况。方法:琼脂稀释法测定17种抗菌药物对MRSA的最低抑菌浓度(MIC)。结果:92株MRSA对实验中所有β-内酰胺类抗生素的耐药率均在80%以上。绝大部分菌株对庆大霉素、红霉素、氟喹诺酮类也不敏感。超过半数的MRSA菌株对利福平保持敏感,对氯霉素、多西环素及米诺环素也普遍敏感,未发现耐万古霉素的MRSA菌株。结论:我院附属第一医院的MRSA呈多重耐药,但对氯霉素,半合成四环素及万古霉素仍然敏感。     

兔胫骨钻骨孔径对骨髓炎模型的影响

背景：直到现在骨髓炎仍然是临床骨科医生需要解决的难题,开发理想的骨髓炎模型对于新治疗方法的评价非常重要。目的：稳定有效地制备出适用于不同实验需求的兔胫骨骨髓炎模型。方法：将25只新西兰大白兔随机分成3组,小孔组10只、大孔组10只、假手术组5只。小孔组采用小孔法,用1 mm钻头在兔胫骨中上段钻孔,注入金黄色葡萄球菌(2×10⁶ cfu)悬浮液100μL;大孔组采用大孔法,用5 mm钻头在兔胫骨中上段钻孔,其余操作同小孔组;假手术组切开后缝合,不进行钻孔及细菌注射。术后1个月内进行一般状态、体温、X射线片、CT、组织病理学观察及血清C-反应蛋白、降钙素原质量浓度测定。结果与结论：(1)与假手术组相比,术后小孔组、大孔组兔体温和血清C-反应蛋白质量浓度均呈现不同程度升高;(2)钼靶X射线片及CT检查：小孔组影像学表现为全骨髓腔感染,大孔组表现为局部骨缺损感染;(3)提示在制备兔胫骨骨髓炎模型时,钻孔大小不同可导致不同的胫骨感染后果,使用5 mm钻孔的模型可能适用于局部抗感染材料效能的研究,使用1 mm钻孔的模型可能适用于全身抗生素药物治疗骨髓炎效果的评价。     

夫西地酸钠和万古霉素用于ICU病房耐甲氧西林 金黄色葡萄球菌患者的疗效比较

目的 对比夫西地酸钠和万古霉素用于ICU病房耐甲氧西林金黄色葡萄球菌（MRSA）患者中的临床效果。方法 选取我院2018年3月~12月收治的ICU病房MRSA患者42例,随机分为参照组和研究组,各21例。参照组给予万古霉素治疗,研究组给予夫西地酸钠治疗,比较两组患者的治疗效果及细菌清除率。结果 参照组与研究组的治疗总有效率分别为90.48%、85.71%,差异无统计学意义（P＞0.05）。参照组与研究组的细菌清除分别为95.24%、90.48%,差异无统计学意义（P＞0.05）。结论 应用夫西地酸钠对ICU病房MRSA患者进行治疗,获得了与万古霉素治疗效果相当的结果,两者细菌清除率也比较接近,因此对此类患者治疗过程中可应用夫西地酸钠作为替代药物。     

ICU中MRSA耐药基因检测及其PFGE分型

目的对耐甲氧西林金黄色葡萄球菌（MRSA）菌株进行分子分型,探讨ICU中MRSA医院感染的特点和流行规律。方法采用表型筛选和PCR扩增mecA基因方法鉴定MRSA菌株。脉冲场凝胶电泳方法（PFGE）进行分子分型。结果12株金黄色葡萄球菌表型筛选为MRSA,MRSA产生A型、B型、C型和D型4种耐药表型,优势耐药模式是A型（75．0％）,MRSA对苯唑西林、阿莫西林／克拉维酸和氨苄西林／舒巴坦等10种抗生素产生100％耐药性,11株MRSA携带mecA基因,携带率为91．7％,PFGE指纹图谱分两型,分别为R1型和R2型,11株MRSA为R1型（91．7％）,R1型各株间相似度为100％。结论ICU可存在MRSA爆发流行,MRSA产生多重耐药性（MDR）,MRSA携带mecA基因可表现为MDR,PFGE分型是理想的分子流行病学溯源手段。     

耐甲氧西林金黄色葡萄球菌对消毒剂和常用抗菌药物的耐药性及相关基因的研究

耐甲氧西林金黄色葡萄球菌（methicillin-resistant Staphylococcus aureus ，MRSA）已成为医院感染的重要病原菌，流行、暴发常有报道，同时社区获得性感染亦逐年增多。金黄色葡萄球菌对甲氧西林耐药是由于获得了携带mec基因的葡萄球菌盒式染色体（staphylococcal cassette chromosome mec，SCCmec），并通过SCCmec不断积累抗生素耐药基因。近年来国内外学者已从金黄色葡萄球菌中检出耐消毒剂基因的菌株。因此，控制MRSA特别是对常用消毒剂如季铵盐类等消毒剂耐药菌株的传播具有实际意义。     

苏州地区耐甲氧西林金黄色葡萄球菌的临床分布特点及耐药性分析

目的 探讨苏州高新区人民医院耐甲氧西林金黄色葡萄球菌(MRSA)的临床分布特点及其耐药性,为临床治疗葡萄球菌属感染提供正确选药依据.方法 对2015年1月至2017年8月苏州高新区人民医院临床各科送检的各类标本中分离鉴定出的MRSA,采用MIC法进行药敏试验,并探讨其临床分布与耐药特点.结果 分离出的170株金黄色葡萄球菌中,MRSA有40株,占23.5%,以呼吸科病房为最多(20株),占50.0%、其次是重症监护病房(ICU)、儿科、神经内科;多重耐药的MRSA对所有β-内酰胺类高度耐药,对大环内酯类耐药率为67.5%;对克林霉素类耐药性较高,其中红霉素诱导的克林霉素耐药率为47.5%,提示该药在苏州地区已不能够用于MRSA 感染的治疗.对氨基糖苷类、氟喹诺酮类耐药率较低(耐药率<30%),磺胺甲噁唑、甲氧苄啶及利福平具有良好的活性,尚未发现耐糖肽类和利萘唑胺的菌株.结论苏州地区近3年来MRSA菌株检出率较低;对常用抗菌素呈多重耐药,尤其是对大环内酯-克林霉素抗菌药物耐药率高.因此应加强对MRSA耐药率的监测,合理选抗菌药物,从而减少MRSA 的产生和传播.     

五味消毒饮联合红霉素对MRSA生物膜作用的初步研究

目的探讨五味消毒饮联合红霉素对耐甲氧西林金黄色葡萄球菌（MRSA）的体外抑菌效果。结论用微量稀释法分别测定红霉素、五味消毒饮的最低抑菌浓度（MIC）及MRSA生物膜MIC（SMIC）,再用微量棋盘稀释法进行联合抑菌试验,观察五味消毒饮联合红霉素抗MRSA的作用。结果五味消毒饮、红霉素单独及联合检测时MRSA的最低抑菌浓度（MIC）和MRSA生物膜MIC（SMIC）分别为〉1000g/ml、8μg/ml、2μg/ml＋/1000g/ml和〉1000g/ml、32μg/ml、8μg/ml＋1000g/ml。结论五味消毒饮联合红霉素可增强对MRSA的抑菌作用,为临床MRSA的感染提供了新的治疗思路。     

Methicillin-resistant Staphylococcus aureus producing Panton–Valentine leukocidin as a cause of acute osteomyelitis in children

Staphylococcus aureus was identified as the cause of acute childhood osteomyelitis in 19 patients. A single clone of community-acquired methicillin-resistant S. aureus (MRSA) carrying the type IV mecA staphylococcal cassette chromosome and the Panton-Valentine leukocidin (PVL) genes was isolated from five patients. Among the remaining 14 patients, two methicillin-sensitive S. aureus (MSSA) isolates were PVL-positive. The maximal erythrocyte sedimentation rate and C-reactive protein values, and the time required for normalisation, were significantly different in patients with PVL-positive strains (MRSA and MSSA), suggesting that the production of PVL is an important factor that contributes to the course of the disease.     

Synergistic effect of vancomycin combined with cefotaxime,imipenem, or meropenem against Staphylococcus aureus with reduced susceptibility to vancomycin

Background/aim We investigated the synergistic effect between vancomycin and β-lactams against vancomycin-susceptible (VSSA) and nonsusceptible MRSA isolates [heterogeneous vancomycin-intermediate S. aureus (hVISA) and VISA].Materials and methods A total of 29 MRSA, including 6 VISA, 14 hVISA, and 9 VSSA isolates, were subjected to a microbroth dilution-minimum inhibitory concentration (MIC) checkerboard using vancomycin combined with cefotaxime, imipenem, or meropenem. To confirm synergistic activity, the representative strains of VISA, hVISA, and VSSA were then selected for the time-kill curve method.Results The combination of vancomycin with imipenem, meropenem, or cefotaxime exhibited synergistic effects against 17 (2 VISA, 9 hVISA, and 6 VSSA), 14 (3 VISA, 9 hVISA and 2 VSSA), and 5 (3 VISA and 2 hVISA) isolates, respectively. Additive and indifferent effects were found in the remaining isolates, but no antagonistic effect was observed. Using time-kill assay, the vancomycin combined with either imipenem or cefotaxime demonstrated synergism against both VISA and hVISA isolates, while the synergistic effect with meropenem was obtained only in the VISA isolates.Conclusion This study demonstrated in vitro enhanced antibacterial activity of vancomycin plus β-lactams against clinical hVISA or VISA isolates. These combinations may be an alternative treatment for MRSA infections in clinical practice.     

Photodynamic therapy induces an immune response against a bacterial pathogen

Photodynamic therapy (PDT) employs the triple combination of photosensitizers, visible light and ambient oxygen. When PDT is used for cancer, it has been observed that both arms of the host immune system (innate and adaptive) are activated. When PDT is used for infectious disease, however, it has been assumed that the direct antimicrobial PDT effect dominates. Murine arthritis caused by methicillin-resistant Staphylococcus aureus in the knee failed to respond to PDT with intravenously injected Photofrin^®. PDT with intra-articular Photofrin produced a biphasic dose response that killed bacteria without destroying host neutrophils. Methylene blue was the optimum photosensitizer to kill bacteria while preserving neutrophils. We used bioluminescence imaging to noninvasively monitor murine bacterial arthritis and found that PDT with intra-articular methylene blue was not only effective, but when used before infection, could protect the mice against a subsequent bacterial challenge. The data emphasize the importance of considering the host immune response in PDT for infectious disease.     

A porcine model of acute, haematogenous, localized osteomyelitis due to Staphylococcus aureus: a pathomorphological study

A porcine model of acute, haematogenous, localized osteomyelitis was established. Serial dilutions of Staphylococcus aureus [5-50-500-5000-50 000 CFU/kg body weight (BW) suspended in saline or saline alone] were inoculated into the right brachial artery of pigs (BW 15 kg) separated into six groups of two animals. During the infection, blood was collected for cultivation, and after the animals were killed from day 5 to 15, they were necropsied and tissues were sampled for histopathology. Animals receiving ≤500 CFU/kg BW were free of lesions. Pigs inoculated with 5000 and 50 000 CFU/kg BW only developed microabscesses in bones of the infected legs. In the centre of microabscesses, S. aureus was regularly demonstrated together with necrotic neutrophils. Often, bone lesions resulted in trabecular osteonecrosis. The present localized model of acute haematogenous osteomyelitis revealed a pattern of development and presence of lesions similar to the situation in children. Therefore, this model should be reliably applied in studies of this disease with respect to e.g. pathophysiology and pathomorphology. Moreover, because of the regional containment of the infection to a defined number of bones, the model should be applicable also for screening of new therapy strategies.     

Predictors of clinical and microbiological treatment failure in patients with methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia: a retrospective cohort study in a region with low MRSA prevalence

Invasive infections with methicillin-resistant Staphylococcus aureus (MRSA) have been associated with increased morbidity and mortality. The aim of the present study was to identify independent predictors of early mortality and treatment failure in patients with MRSA bacteraemia. A total of 132 adult patients who developed MRSA bacteraemia during hospitalization in the University Hospital of Vienna between 2000 and 2011 were screened and 124 were included in a retrospective cohort study. Patient demographics, source of bacteraemia, antimicrobial treatment and microbiological characteristics were evaluated. The 28-day crude mortality was 30.6%. Predictors of early mortality identified in multivariate Cox regression analysis included higher patientage (adjusted hazard ratio (aHR) 1.03, 95% CI 1.01–1.06, p 0.006), pneumonia (aHR 3.86, 95% CI 1.83–8.12, p <0.001) and failure to use MRSA active treatment (aHR 8.77, 95% CI 3.50–21.93, p <0.001). Ninety-one (73.4%) patients received glycopeptides as specific MRSA treatment. Of 63 patients treated with vancomycin, only 14 (22.6%) patients had aimed trough levels of 15–20 mg/L. Vancomycin MIC ≥ 2 mg/L was detected in 28.2% and was associated with glycopeptide pretreatment (p 0.001). All MRSA isolates were susceptible to linezolid and tigecycline. Persistent bacteraemia ≥ 7 days was documented in 25 (20.2%) patients. Independent determinants for microbiological eradication failure in patients with MRSA bacteraemia included endocarditis (p <0.001) and vancomycin trough levels (p 0.014), but not vancomycin MIC. Failure of clinical and microbiological eradication of MRSA among patients with MRSA bacteraemia was associated with clinical entity rather than with bacterial traits. Pharmacokinetic parameters seem to be decisive on microbiological and clinical success.     

金黄色葡萄球菌性骨髓炎动物模型构建的研究与进展

文题释义： 骨髓炎：由传染性微生物引起的骨和骨髓的急性或慢性炎症性疾病,可由需氧或厌氧菌、分枝杆菌及真菌引起,流行性病学显示金黄色葡萄球菌是导致骨髓炎最常见、最主要致病菌。骨髓炎好发于长骨、糖尿病患者的足部或由于外伤或手术引起的穿透性骨损伤部位。 菌落形成单位(Colony-Forming Units,CFU)：是指在琼脂平板上经过一定温度和时间培养后形成的每一个菌落,是计算细菌或霉菌数量的单位。这个单位比“菌落数”更准确地反映问题的实质。理论上,一个活细菌可以在条件合适的固体表面上形成一个菌落,但是吸附于微小颗粒上的2个以上菌体或粘连在一起的菌团可能共同形成一个菌落,而且不同环境因素作用下,细菌的生活能力各不相同,会影响其在该条件下形成菌落的能力,致使形成的菌落数远低于实际的活菌数。因此目前可用菌落形成单位代替以往常用的“菌落数”作为平板计数的数量单位。 背景：金黄色葡萄球菌已成为目前全世界骨髓炎最主要的致病菌。优秀而标准的同质性动物模型对骨髓炎感染机制的研究、获得新的预防与治疗措施及新技术转化应用于临床实践的科学研究具有重要作用。 目的：综述国内外金黄色葡萄球菌性骨髓炎动物模型构建的相关研究进展及面临的问题。 方法：计算机检索CNKI数据库、PubMed数据库、MEDLINE数据库、Embase数据库、Cochrane 图书馆的相关文献,中文检索词为“金黄色葡萄球菌;骨感染;骨髓炎;置入物相关骨髓炎;骨缺损骨髓炎;骨折骨髓炎;生物膜;实验性骨髓炎模型;动物模型”;英文检索词为“Staphylococcus aureus; bone infection; osteomyelitis; implant-associated osteomyelitis; bone defect osteomyelitis; fracture osteomyelitis; biofilm; experimental osteomyelitis model”。语言分别设为中文和英文。查阅2010年1月至2019年6月期间收录的相关文章,包括综述、基础研究以及临床研究。通过阅读文题和摘要进行初步筛选,排除与文章主题不相关的文献,根据纳入标准和排除标准,最终纳入45篇文献进行结果分析。 结果与结论：①骨髓炎动物模型的构建方法与多种因素有关,尽管近年来各国研究者对此不断进行改进并逐渐量化感染过程,但尚未形成统一标准;②目前并无单一微生物学或影像学检查方式能明确骨感染,在急性骨髓炎动物模型中,nuc RTQ-PCR技术和生物荧光成像技术等微生物学检测能够早期动态监测并量化骨感染过程;对于慢性骨髓炎动物模型,micro-CT、MRI等影像学技术能动态观察骨溶解、骨重建过程,且¹⁸F-FDG PET/CT等尖端成像技术确认或排除慢性骨髓炎有很高的诊断准确性;③基于骨髓炎动物模型,确定早期诊断及量化诊疗过程中感染细菌数量及活性的标准,也是今后进一步研究的方向。 ORCID: 0000-0002-2767-4895(刘金月) 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

Innovations in osteomyelitis research: A review of animal models

Infection of bone tissue, or osteomyelitis, has become a growing concern in modern healthcare due in no small part to a rise in antibiotic resistance among bacteria, notably Staphylococcus aureus. The current standard of care involves aggressive, prolonged antibiotic therapy combined with surgical debridement of infected tissues. While this treatment may be sufficient for resolving a portion of cases, recurrences of the infection and associated risks including toxicity with long‐term antibiotic usage have been reported. Therefore, there exists a need to produce safer, more efficacious options of treatment for osteomyelitis. In order to test treatment regimens, animal models that closely mimic the clinical condition and allow for accurate evaluation of therapeutics are necessary. Establishing a model that replicates features of osteomyelitis in humans continues to be a challenge to scientists, as there are many variables involved, including choosing an appropriate species and method to establish infection. This review addresses the refinement of animal models of osteomyelitis to reflect the clinical disease and test prospective therapeutics. The aim of this review is to explore studies regarding the use of animals for osteomyelitis therapeutics research and encourage further development of such animal models for the translation of results from the animal experiment to human medicine.