Community-onset healthcare-associated MRSA bacteraemia in a district general hospital

Methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia is associated with significant mortality and morbidity. This retrospective study involved 76 episodes over four years in a district general hospital in the UK. Twenty-eight of these episodes (36.8%) occurred within 72 h of admission. All of these, however, had risk factors for MRSA acquisition and were classified as healthcare-associated bacteraemias. The mortality rates (all causes) at seven days and three months were 31.5% and 53.4%, respectively. Ten patients died before targeted therapy could be commenced. All patients in the study had multiple comorbidities, and pneumonia was a common diagnosis. Previous antibiotics, increased age, admission on surgical wards/intensive care units, and the presence of central venous cannulae and urinary catheters were risk factors for infection. In 48.7% of episodes, patients were not known to be colonized with MRSA prior to their bacteraemia. Empirical targeted therapy should be given to patients with risk factors for MRSA and staphylococci in blood cultures pending susceptibility results. Increased use of screening may also be required to reduce transmission and increase the likelihood of appropriate empirical antimicrobial therapy. Eradication of MRSA from carriers in the community should be considered to reduce the number of community-onset healthcare-associated bacteraemias.     

Epidemiology and outcomes for Staphylococcus aureus bacteraemia in Australian hospitals, 2005-06: report from the Australian Group on Antimicrobial Resistance

The Australian Group on Antimicrobial Resistance studied the epidemiology and outcomes of Staphylococcus aureus bacteraemia in selected Australian hospitals in 2005-06. Seventeen hospital-based laboratories collected basic demographic, susceptibility and patient outcome data on all cases of S. aureus bacteraemia for 5 to 24 months during the study period. There were 1,511 cases of bacteraemia documented, of which 66% occurred in males and 32% originated from vascular access devices. Bacteraemia had a community onset in 60% of cases, although 31% of these were health-care associated. Overall, 57% of episodes were health-care related. Methicillin-resistant Staphylococcus aureus (MRSA) was the responsible pathogen in 24% of instances; of these 53% were of the typical multi-resistant hospital type, and 29% were of the community-associated type. Seven per cent of all staphylococcal bacteraemias were caused by community-associated MRSA strain types, attesting to the growing size of this problem in Australia. Outcomes were available for 51% of cases and in those the all-cause mortality at 7 days or discharge (whichever came earlier) was 11.2%. Age was strongly associated with mortality; the rate for patients aged more than 60 years was 18%. Sepsis originating from intravascular access devices had a lower mortality rate of 5%. S. aureus bacteraemia is a common community and hospital infection with a significant mortality. A nationally co-ordinated program documenting the incidence and outcomes of this disease would likely lead to measures designed to reduce the incidence and improve outcomes of this disease.     

Hong Kong strains of methicillin-resistant and methicillin-sensitive Staphylococcus aureus have similar virulence

While most authorities agree that methicillin-resistant Staphylococcus aureus (MRSA) are as pathogenic as methicillin-sensitive strains (MSSA), some believe that MRSA are relatively avirulent opportunists, and that their importance has been exaggerated. We present evidence that Hong Kong strains of MRSA and MSSA are equally pathogenic: they have similar virulence in animal models; they are isolated in similar proportions from both deep and superficial clinical sites including blood; in patients with hospital-acquired bacteraemias mortality rates are similar when adjusted for clinical factors; and in both animals and patients with systemic MRSA infection, mortality rates are significantly reduced by vancomycin therapy. Efforts to control the spread of MRSA are justified, and in invasive sepsis early treatment with vancomycin may be life-saving.     

Staphylococcus aureus bacteraemia: incidence, risk factors and predictors for death in a Brazilian teaching hospital

The aim of this study was to evaluate the incidence of bloodstream infection due to Staphylococcus aureus and the risk factors for mortality. The design was a two-year retrospective cohort of patients more than one year of age with clinically significant and microbiologically documented bloodstream infection due to S. aureus between January 2000 and December 2001 in a tertiary teaching hospital in midwest Brazil. One hundred and eleven patients were identified with clinically significant and microbiologically confirmed bacteraemia due to S. aureus, accounting for an infection rate of five per 1000 admissions. Nosocomial infections represented 83.8% of cases and meticillin-resistant Staphylococcus aureus (MRSA) accounted for 60.2% of cases. Overall mortality due to S. aureus bacteraemia was 35.1%. Infection due to MRSA, severity of clinical status (severe sepsis or septic shock) and inadequate initial antimicrobial therapy were identified by univariate analysis as predictors of mortality. After Cox regression analysis, severity of clinical manifestations [hazard ratio (HR) 6.86, 95% confidence interval (CI) 3.05-15.43] and inadequacy of antimicrobial therapy (HR 2.27, 95%CI 1.02-5.09) remained as risk factors for mortality. Early diagnosis of bacteraemia should be sought in order to implement adequate treatment before the onset of severe sepsis and septic shock, thus reducing the mortality rate.     

新生儿病房分离金黄色葡萄球菌耐药性及耐消毒剂基因检测

目的了解新生儿病房送检标本中金黄色葡萄球菌的耐药谱及耐消毒剂基因携带情况。方法收集2013年1—12月某院新生儿病房住院新生儿送检标本分离的金黄色葡萄球菌,采用VITEK2 Compact细菌鉴定分析系统进行细菌鉴定及药敏试验,采用聚合酶链反应(PCR)检测耐消毒剂qacA/B基因。结果新生儿科送检标本中共分离225株金黄色葡萄球菌,主要来源于呼吸道(72.44%)和脐部分泌物(14.33%);耐甲氧西林金黄色葡萄球菌(MRSA)检出率为8.89%(20株);耐药监测中,MRSA的耐药率普遍高于甲氧西林敏感金黄色葡萄球菌(MSSA)。左氧氟沙星、莫西沙星、替加环素、万古霉素、利奈唑胺及呋喃妥因对所有金黄色葡萄球菌均显示出良好的抗菌活性,敏感率均为100%。携带qacA/B基因的金黄色葡萄球菌有21株,阳性率为9.33%,其中MRSA3株(15.00%),MSSA18株(8.78%)。结论新生儿病房分离的MRSA耐药严重,同时携带qacA/B基因,应引起临床重视。     

Nasal carriage and antibiotic resistance of Staphylococcus aureus isolates from hospital and non-hospital personnel in Abha, Saudi Arabia

The prevalence of nasal carriage of Staphylococcus aureus, antibiograms and prevalence of methicillin-resistant S. aureus (MRSA) were studied in 1999 among healthy hospital and non-hospital personnel in Abha, Saudi Arabia. S. aureus was isolated from 26.1% of 299 adults in the community and 25.4% of 279 hospital personnel. No isolate was resistant to vancomycin. Antibiotic resistance rates, for all other antibiotics tested except cephalothin, were significantly higher for strains from hospital personnel (P values < 0.001-0.04) compared to non-hospital adults. The antibiograms were also compared with those of 140 clinical isolates. The rates of resistance of the inpatient strains to all the antibiotics tested were significantly higher than those of hospital nasal carrier strains (P < 0.001-0.05). MRSA was isolated, respectively, from 5.1% and 18.3% of non-hospital and hospital carriers; MRSA carriage rates were 1.3% and 4.7%, respectively, for non-hospital and hospital carriers, and 61% of S. aureus isolates from infected patients were MRSA. Only 8% of non-hospital but 44% of hospital carrier strains were multiply resistant (P < 0.001). Multiple resistance among inpatient strains (89%) was significantly higher than that among hospital nasal strains (44%) (P < 0.001). Such rates of multiple resistance and endemic MRSA prevalence among healthy carriers (11%) at a much higher rate than those reported in the literature should raise concern in a region with unrestricted availability of antibiotics.     

MRSA surveillance in a UK district hospital: measuring clinical isolates with MRSA is more useful than measuring MRSA bacteraemias

The introduction of mandatory surveillance of meticillin-resistant Staphylococcus aureus (MRSA) bacteraemias and targets in England has led to reductions in most hospitals. However, reductions were difficult to demonstrate at Peterborough & Stamford Hospitals NHS Foundation Trust as MRSA bacteraemia was already an uncommon event. The authors questioned the efficacy of monitoring bacteraemias in a low-prevalence hospital, and this study sought to determine the accuracy of measuring bacteraemias compared with all clinical isolates (excluding bacteraemias; e.g. wound, sputa, urine) to assess the effectiveness of interventions. Over the six-year study period, a significant reduction was seen in MRSA in clinical specimens and new MRSA carriers identified by screening, whereas the MRSA bacteraemia rate remained at low levels. The measurement of clinical isolates may be more useful for assessment of the effectiveness of interventions now that MRSA bacteraemia rates have fallen to low levels almost universally across the UK.     

Methicillin-resistant Staphylococcus aureus bacteraemia in Western Australian teaching hospitals, 1997-1999: risk factors, outcomes and implications for management

The aim of this study was to document the evolution of methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia at teaching hospitals in Perth, Western Australia (WA), and determine the risk factors and outcomes of the disease. We performed a retrospective case series analysis of all laboratory-confirmed episodes of S. aureus bacteraemia at Perth teaching hospitals between 1 July 1997 and 30 June 1999 by linking laboratory data with hospitalization data from the state's Hospital Morbidity Data System. Episodes of S. aureus bacteraemia were stratified according to methicillin susceptibility and the relationship between methicillin resistance and key factors or outcomes was determined. Almost 11% of episodes of S. aureus bacteraemia (55/509) were caused by MRSA. On age-adjusted multivariate analysis, Aboriginality (RR 6.71, 95% CI 3.20-14.10, P<0.001), geriatric unit admission (RR 5.74, 95% CI 2.01-16.37, P=0.001), female sex (RR 1.88, 95% CI 1.03-3.42, P=0.04) and healthcare-associated disease (RR 1.93, 95% CI 1.01-3.70, P=0.05) were independently associated with MRSA bacteraemia. Outcomes among those with MRSA bacteraemia included death in 15 patients and re-admission for an MRSA-related complication in five. Empirical use of vancomycin needs consideration in at-risk patients in whom Gram-positive bacteraemia is suspected clinically, with prompt review of therapy once antibiotic susceptibility results are known. The rates of re-admission after discharge for MRSA bacteraemia could be used as a clinical indicator to monitor the quality of care in hospitals.     

Enhanced surveillance of meticillin-resistant Staphylococcus aureus bacteraemia in a London teaching hospital

In 2001, the UK Department of Health introduced mandatory surveillance of meticillin-resistant Staphylococcus aureus (MRSA) bacteraemias (blood-culture-positive episodes) in English hospitals. We performed enhanced surveillance in their hospital between April 2001 and March 2003 to determine the epidemiology of MRSA bacteraemia across different specialities. There were 267 MRSA-blood-culture-positive episodes, giving a rate of 0.37 per 1000 occupied bed-days (OBD). Thirty-three (12.4%) episodes were false positives due to contaminants and 15 (5.6%) originated in the community or at another institution. Thirty-one (11.6%) episodes were in outpatients or occurred after recent discharge and were designated 'hospital associated'. The remaining 188 cases were clinically significant hospital-acquired episodes in inpatients, with a rate of 0.26 per 1000 OBDs. The highest rates were in the intensive therapy unit (ITU; 2.74 per 1000 OBDs) and the high-dependency unit (HDU; 1.68 per 1000 OBDs). Fifty-five non-ITU, non-HDU episodes occurred in patients who had been discharged from ITU or HDU prior to the development of bacteraemia but during the same admission. The number of MRSA bacteraemias related to ITU/HDU suggests that these wards may be hubs of MRSA infection. Haematology, oncology and renal (HOR) patients had the greatest number of hospital-associated episodes. The most common source of MRSA bacteraemia was a vascular access device (VAD) (108 episodes, 57%, 64% of which were central lines). The high bacteraemia rates in ITU, HDU and HOR patients were associated with high usage of VADs. The majority of episodes occurred in patients who were newly colonized with MRSA after admission. Thus, in this hospital, VADs and stays in ITU or HDU are important risk factors for bacteraemia, and VAD care and prevention of cross-infection are priorities for intervention. We recommend that the mandatory national surveillance scheme should collect additional data on MRSA bacteraemia to provide information for a national strategy for MRSA control and to allow appropriate comparison between institutions.     

临床分离金黄色葡萄球菌的耐药特点和MRSA分子分型

目的研究耐甲氧西林金黄色葡萄球菌(MRSA)的耐药性及其基因分型。方法收集某院2014年1月—2015年11月检出的非重复金黄色葡萄球菌967株,检测其药敏结果及mecA抗性基因、杀白细胞素(PVL)基因;MRSA菌株经多重PCR进行葡萄球菌盒式染色体mec(SCCmec)分型、多位点序列分型(MLST)、金黄色葡萄球菌蛋白A基因(spa)分型、金黄色葡萄球菌附属因子调节子(agr)分型。结果 967株金黄色葡萄球菌共检出210株MRSA,MRSA检出率为21.72%;痰标本MRSA检出率高于皮肤软组织标本(68.09%vs 11.83%,P0.05);金黄色葡萄球菌中未发现对万古霉素和利奈唑胺耐药菌株,MRSA对庆大霉素、四环素、红霉素、克林霉素、左氧氟沙星、环丙沙星、莫西沙星、呋喃妥因、利福平的敏感率均低于MSSA,差异均有统计学意义(均P0.05);MRSA对复方磺胺甲口恶唑的敏感率高于MSSA,差异有统计学意义(P0.05)。皮肤软组织分离的MRSA对庆大霉素、左氧氟沙星、环丙沙星、莫西沙星、利福平的敏感率为86.90%~95.24%,而痰分离的MRSA仅为1.56%~15.63%。967株金黄色葡萄球菌检测出210株携带mecA基因,10株携带PVL基因,210株MRSA中有8株未分型,占3.81%。MLST主要以ST239(177株)为主;SCCmec分型主要以Ⅲ型(177株)为主;spa分型主要以t 030(177株)为主;agr分型主要以Ⅰ型(196株)为主。结论该院MRSA菌株主要流行克隆ST239-MRSA-SCCmecⅢ-t030,耐药形势严峻,应加强医院内耐药菌株的监测。     

Cost-effectiveness of active surveillance cultures and contact/droplet precautions for control of methicillin-resistant Staphylococcus aureus

Some have reported that adopting Centers for Disease Control and Prevention guidelines requiring contact precautions for methicillin-resistant Staphylococcus aureus (MRSA) had no impact on rates of nosocomial spread or infection, and may therefore waste money. The objective of the present study was to evaluate the cost-effectiveness of active surveillance cultures and barrier precautions for controlling MRSA. Estimated costs of surveillance cultures and isolation measures used during an MRSA outbreak at this hospital were compared with the estimated attributable excess costs of methicillin resistance (i.e., the difference between MRSA and methicillin-sensitive S. aureus costs) for bacteraemias occurring during an MRSA outbreak not promptly controlled at another hospital. The study was set in the neonatal intensive care units of two tertiary care hospitals. Estimated costs of controlling the 10.5-month outbreak in this neonatal intensive care unit that resulted in 18 colonized and four infected infants ranged from $48 617 to $68 637. The estimated attributable excess cost of 75 MRSA bacteraemias in a second neonatal intensive care unit outbreak that resulted in 14 deaths and lasted 51 months was $1 306 600. Weekly active surveillance cultures and isolation of patients with MRSA halted an outbreak at this hospital, and cost 19- to 27-fold less than the attributable costs of MRSA bacteraemias in another outbreak that was not promptly controlled. The costs of infections at other body sites and the human cost of deaths from infection were not estimated but would further help to justify the cost of identifying colonized patients and implementing effective preventive measures.     

医院感染葡萄球菌耐药性监测

目的了解我院医院感染葡萄球菌耐药状况. 方法药敏试验采用K-B纸片法,判定标准依据美国国家临床实验室标准化委员会(NCCLS)标准. 结果 1999～2003年我院医院感染金黄色葡萄球菌423株,对甲氧西林耐药菌株MRSA及敏感菌株MSSA分别为79株和334株,表皮葡萄球菌898株,对甲氧西林耐药菌株MRSE及敏感菌株MSSE分别为647株和251株;MSSA、MSSE对临床常用抗生素敏感,但对青霉素、红霉素、阿奇霉素耐药率>70%;MRSA、MRSE对临床常用抗生素均高度耐药,只有万古霉素100%敏感. 结论了解医院感染葡萄球菌的耐药状况,对临床合理选择抗生素十分重要,万古霉素可作为葡萄球菌重症感染的首选药物.     

医院感染革兰阳性球菌耐药性分析

目的了解医院感染革兰阳性（G^＋）球菌分布及耐药特点，为临床治疗提供依据。方法对某院2006年临床送检的8719份标本，常规培养、分离细菌并采用VITEK-2和API系统鉴定；纸片扩散法和肉汤稀释法对细菌进行药敏试验；WHONET5．4和SPSS11．5统计软件对数据进行统计分析。结果共分离细菌3584株（41．11％），其中G^＋菌777株（21．68％），主要为凝固酶阴性葡萄球菌（CNS）259株，金黄色葡萄球菌（SA）234株，肠球菌属（ENT）156株。其中分离耐甲氧西林SA（MRSA）123株（占SA52．56％），耐甲氧西林CNS（MRCNS）214株（占CNS82．63％），粪肠球菌41株（占ENT26．28％），屎肠球菌107株（占ENT68．59％）。未发现对万古霉素和替考拉宁耐药的葡萄球菌属和粪肠球菌，发现1株对替考拉宁和万古霉素同时耐药和3株对万古霉素中介耐药的屎肠球菌；屎肠球菌对大多数抗菌药物的耐药率高于粪肠球菌（P〈0．01）；肺炎链球菌对青霉素的耐药率为64．28％。结论此次分离的G^＋菌以球菌为主，其中的葡萄球菌属以MRSA和MRCNS为主；分离到对万古霉素和替考拉宁耐药的屎肠球菌，以及对青霉素耐药的肺炎链球菌；屎肠球菌耐药性高于粪肠球菌。     

基层医院金黄色葡萄球菌的临床分布及耐药性分析

目的调查金黄色葡萄球菌的临床分布及耐药率,以指导临床合理用药.方法回顾性的分析我院4年来临床各类送检标本中金黄色葡萄球菌的分离情况及耐药状况.结果分离出的137株金黄色葡萄球菌主要来源于痰、皮肤及软组织脓液;伤口分泌物分离的金黄色葡萄球菌医院感染率最高;伤口分泌物及痰标本中的MRSA分离率最高,分别为75.0%和66.1%;对常用抗生素的耐药水平均较高,但尚未发现对万古霉素耐药菌株.结论基层医院金黄色葡萄球菌的分离率及耐药率均有较明显的上升趋势,且不同来源标本的分离及耐药情况有较大的差别.     

2006-2010年耐甲氧西林金黄色葡萄球菌的测定与耐药性变迁

目的 了解2006-2010年医院耐甲氧西林金黄色葡萄球菌(MRSA)的检出率与耐药性变迁.方法 采用VITEK-60全自动微生物分析仪对菌株进行鉴定及药敏检测,药敏结果使用WHONET软件进行分析.结果 共检出金黄色葡萄球菌867株,45.4％来自于脓液/创面,其次是呼吸道标本占22.6％;2006-2010年MRSA检出率分别为28.7％、31.5％、39.2％、53.6％、44.6％;MRSA对利奈唑胺、万古霉素的敏感率为100.0％.结论 临床医师在治疗由MRSA引起的感染时首选利奈唑胺、万古霉素,严格要求医护人员在为患者治疗前后手卫生,一旦检测到MRSA应加强隔离预防,控制在医院内的扩散.     

耐甲氧西林金黄色葡萄球菌的目标性监控与分析

目的 了解临床耐甲氧西林金黄色葡萄球菌的分离及耐药性,探索耐甲氧西林金黄色葡萄球菌感染病例的监控措施.方法 对2010年医院临床分离的病原菌进行目标性监测,统计出耐甲氧西林金黄色葡萄球菌的株数以及耐药性,并对临床耐甲氧西林金黄色葡萄球菌感染病例实施监控.结果 全年检测结果发现,共分离出金黄色葡萄球菌334株,耐甲氧西林金黄色葡萄球菌50株,检出率为14.97％;对抗菌药物耐药率较高;全院未发生耐甲氧西林金黄色葡萄球菌的暴发和流行.结论 耐甲氧西林金黄色葡萄球菌分离株数较多,耐药率较高,应该加强临床合理使用抗菌药物的管理,并对耐甲氧西林金黄色葡萄球菌感染病例实施监控,预防和减少多药耐药菌的产生,控制医院感染.     

MRSA bacteraemia: North/South Study of MRSA in Ireland 1999

Retrospective aggregate data on all Staphylococcus aureus isolates recovered from blood cultures during 1998 were collected in both jurisdictions on the island of Ireland, Northern Ireland (North) and the Republic of Ireland (South), as part of the North/South Study of MRSA in Ireland 1999. A postal questionnaire was used to gather the data, and all diagnostic microbiology laboratories in the North and 98% of laboratories in the South participated. S. aureus bacteraemia occurred at rates of 20.4 per 100,000 population in the North and 24.5 per 100,000 in the South (missing data from one laboratory). In the North, 22% of patients who had blood cultures positive for S. aureus had methicillin-resistant S. aureus (MRSA) and 25% of S. aureus isolates were MRSA (some patients had more than one isolate). In the South, 31% of patients who had blood cultures positive for S. aureus had MRSA and 36% of S. aureus isolates were MRSA. There was a marked variation in rates between different regions. The percentage of patients with blood cultures positive for S. aureus that had MRSA was considerably lower in the North (22%) than in the South (31%), and in both jurisdictions was lower than that found in England and Wales in 1999 (37%). It is recommended that data on S. aureus bacteraemia and methicillin-resistance rates (already available in many laboratories) are gathered at regional and national level for the surveillance of antimicrobial resistance.     

Staphylococcus aureus with reduced susceptibility to vancomycin--Illinois, 1999

Staphylococcus aureus is one of the most common causes of hospital- and community-acquired infections. Nosocomial methicillin-resistant S. aureus (MRSA) infections have become common, and cases of community-acquired MRSA infections also have occurred. Since 1996, vancomycin-intermediate S. aureus (VISA; vancomycin minimum inhibitory concentration [MIC = 8-16 microg/mL) has been identified in Europe, Asia, and the United States. The emergence of reduced vancomycin susceptibility in S. aureus increases the possibility that some strains will become fully resistant and that available antimicrobial agents will become ineffective for treating infections caused by such strains. This report describes the fourth case of confirmed VISA from a patient in the United States.     

耐甲氧西林金黄色葡萄球菌感染分布及耐药性分析

目的 了解耐甲氧西林金黄色葡萄球菌(MRSA)感染的分布及耐药性,为临床合理用药提供参考依据.方法 采用头孢西丁纸片法检测临床分离的173株金黄色葡萄球菌中MRSA,用K-B纸片法检测MRSA对常用抗菌药物的敏感性.结果 173株金黄色葡萄球菌中检出92株MRSA,检出率为53.2％;其中,呼吸道标本中检出率最高,占46.2％;MRSA对万古霉素、替考拉宁100.0％敏感,对磺胺甲噁唑/甲氧苄啶和利福平的耐药率较低,为23.9％、27.2％;对青霉素和苯唑西林耐药率为100.0％;对左氧氟沙星、红霉素、庆大霉素、克林霉素的耐药率均＞70.0％.结论 MRSA具有多药耐药性,临床应加强对MRSA的耐药性监测,在治疗时应依据药敏试验结果合理使用抗菌药物.