金黄色葡萄球菌医院感染的临床分布及耐药性分析

目的 了解金黄色葡萄球菌(SAU)医院感染的临床分布及耐药特性.方法 回顾性调查2009年1月-2010年12月从临床各类标本中分离获得的168株SAU,统计其在各类标本和病区的分布特点,并用KB法测定常用抗菌药物的敏感性.结果 168株SAU中有117株为MRSA,占69.6％;SAU的耐药率普遍较高,除对万古霉素、替考拉宁、利奈唑胺全部敏感外,对青霉素类、氨基糖苷类、喹诺酮类和磺胺类药物的耐药率均＞60.0％;SAU以痰液、尿液和血液标本检出数最多,分别为24.4％、21.4％和18.5％;科室分布ICU占20.2％、呼吸内科占16.1％、肾内科占14.9％及中医科占14.3％.结论 SAU的耐药率呈上升趋势,且MRSA检出率日趋严重,已对临床抗菌药物的选择构成困难,必须加强对高危病区及高危人群的监测,做好预防和消毒隔离,防止SAU,特别是MRSA的流行播散.     

Epidemiology of community-acquired methicillin-resistant Staphylococcus aureus skin infections among healthcare workers in an outpatient clinic.

We describe an investigation of soft-tissue infections caused by community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) strains in 2 healthcare workers employed in an outpatient clinic for patients with human immunodeficiency virus infection. Cultures of environmental samples from multiple surfaces in the clinic grew toxin-producing CA-MRSA strains, suggesting fomites may play a role in the transmission of these strains of MRSA.     

金黄色葡萄球菌医院感染的临床分布及耐药性分析

目的 了解金黄色葡萄球菌(SAU)医院感染的临床分布及耐药特性.方法 回顾性调查2009年1月-2010年12月从各类临床标本中分离获得的168株SAU,统计其在各类标本和病区的分布特点,并用K-B法测定常用抗菌药物的敏感性.结果 SAU以痰、尿液和血液标本检出数最多,构成比分别达24.4％、21.4％和18.5％;科室分布以ICU、呼吸内科、肾内科和中医科最多,构成比分别达20.2％、16.1％、14.9％和14.3％;168株SAU中有117株为MRSA,占69.6％,SAU的耐药性普遍较高,除对万古霉素、替考拉宁、利奈唑胺全部敏感外,对青霉素类、氨基糖苷类、喹诺酮类和磺胺类药物的耐药率均＞60.0％.结论 SAU的耐药率呈上升趋势,且MRSA检出率日趋严重,已对临床抗菌药物的选择构成极大的困难,必须加强对高危病区和高危人群的监测,做好预防和消毒隔离,防止SAU,特别是MRSA的流行播散.     

Are laptop ventilation-blowers a potential source of nosocomial infections for patients?

Inadequately performed hand hygiene and non-disinfected surfaces are two reasons why the keys and mouse-buttons of laptops could be sources of microbial contamination resulting consequently in indirect transmission of potential pathogens and nosocomial infections. Until now the question has not been addressed whether the ventilation-blowers in laptops are actually responsible for the spreading of nosocomial pathogens. Therefore, an investigational experimental model was developed which was capable of differentiating between the microorganisms originating from the external surfaces of the laptop, and from those being blown out via the ventilation-blower duct. Culture samples were taken at the site of the external exhaust vent and temperature controls were collected through the use of a thermo-camera at the site of the blower exhaust vent as well as from surfaces which were directly exposed to the cooling ventilation air projected by the laptop. Control of 20 laptops yielded no evidence of microbial emission originating from the internal compartment following switching-on of the ventilation blower. Cultures obtained at the site of the blower exhaust vent also showed no evidence of nosocomial potential. High internal temperatures on the inner surfaces of the laptops (up to 73°C) as well as those documented at the site of the blower exhaust vent (up to 56°C) might be responsible for these findings.     

Staphylococcus aureus colonization among healthcare workers at a tertiary care hospital.

We describe the epidemiology of Staphylococcus aureus colonization among 200 healthcare workers. The prevalence of S. aureus was 28%, and the prevalence of methicillin-resistant S. aureus (MRSA) was 2%. The incidence of MRSA colonization was extremely low. This study suggests that the risk of MRSA transmission to healthcare workers is low in a hospital where MRSA is endemic.     

Pigs as source of methicillin-resistant Staphylococcus aureus CC398 infections in humans, Denmark

An emerging subtype of methicillin-resistant Staphylococcus aureus (MRSA), clonal complex (CC) 398, is associated with animals, particularly pigs. We conducted a matched case-control and a case-case study comparing 21 CC398 case-patients with 2 controls randomly selected from the Danish Civil Registry and 2 case-patients infected with MRSA other than CC398. On farms of case-patients, animals were examined for MRSA. Thirteen case-patients reported pig exposure. Living or working on farms with animals was an independent risk factor for CC398 in the case-control (matched odds ratio [MOR] 35.4, 95% confidence interval [CI] 2.7-469.8) and the case-case study (MOR 14.5, 95%CI 2.7-76.7). History of hospitalization was associated with an increased risk only in the case-control study (MOR 11.4, 95% CI 1.4-94.8). A total of 23 of 50 pigs on 4 of 5 farms were positive for CC398. Our results, corroborated by microbiologic testing, demonstrate that pigs are a source of CC398 in Denmark.     

肿瘤患者耐甲氧西林金黄色葡萄球菌医院感染耐药性分析

目的研究肿瘤患者耐甲氧西林金黄色葡萄球菌(MRSA)医院感染现状及耐药性,以指导临床合理选用抗菌药物并为预防与控制医院感染提供科学依据。方法严格按照《全国临床检验操作规程》进行MRSA分离、鉴定,采用K-B法进行药敏试验,依据CLSI最新拆点判读结果。结果 67株葡萄球菌属中金黄色葡萄球菌18株,占26.87%,其中MRSA12株,MRSA分离率66.67%;MRSA主要分离自痰标本5株,占41.67%,其次是腹水标本3株,占25.00%;科室来源主要为肿瘤内科及肿瘤外科,分别占50.50%、41.67%;MRSA除对替考拉宁、夫西地酸、万古霉素等100.00%敏感外,对常用抗菌药物均存在较高的耐药性,MRSA对苯唑西林和青霉素耐药率100.00%,对氨基糖苷类、大环内酯类等抗菌药物耐药率>80.00%,未发现耐万古霉素菌株。结论了解MRSA感染的分布与特征、监测其耐药性,有助于临床及时采取合理的防治措施,有效预防与控制MRSA医院感染的暴发流行。     

医院感染金黄色葡萄球菌耐药表型与耐药基因研究

目的研究医院感染耐药金黄色葡萄球菌的耐药表型及耐药基因,以期为临床防治医院感染提供参考。方法选取2011年1月-2013年1月医院感染患者送检标本中分离的120株金黄色葡萄球菌,根据美国临床实验室标准化研究所(CLSI)标准操作规程以及聚合酶链反应(PCR)分析金黄色葡萄球菌的耐药表型与耐药基因。结果金黄色葡萄球菌耐药率较高的抗菌药物为青霉素、红霉素、庆大霉素、克林霉素、四环素、环丙沙星,耐药率分别为100.00%、98.83%、80.00%、76.67%、76.67%、75.83%,对万古霉素、利奈唑胺较敏感;金黄色葡萄球菌各耐药表型中,以Ⅵ型97.50%的耐药率最高,其次分别为Ⅴ型(67.50%)、Ⅳ型(60.00%);金黄色葡萄球菌各耐药基因中,以mecA98.83%的耐药率最高,且金黄色葡萄球菌耐药基因的耐药性与金黄色葡萄球菌对抗菌药物的耐药性一致。结论医院感染金黄色葡萄球菌对多数抗菌药物的耐药率较高,对万古霉素高度敏感;耐药表型以Ⅵ、Ⅴ、Ⅳ型为主,耐药基因以tetK及mecA为主。     

Cockroaches as potential vectors of nosocomial infections.

OBJECTIVE: To determine the possible role of cockroaches in the epidemiology of nosocomial infections. DESIGN: Epidemiologic investigation of bacteria and fungi in cockroaches and evaluation of the antibiotic resistance of the bacteria isolated from the insects. SETTING: Ninety hospitals in Kaohsiung City and Kaohsiung County in Taiwan. METHODS: Cockroaches were collected in clinical and nonclinical areas and microorganisms were isolated from their external surface and alimentary tract. The susceptibilities of Staphylococcus aureus, Enterococcus species, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Serratia marcescens, and Proteus species to 17 antibiotics were tested. RESULTS: Cockroach infestation was found in 46.7% of the hospitals studied. Two hundred three cockroaches were collected (139 Periplaneta americana and 64 Blattella germanica). Periplaneta americana was found more often in nonclinical areas (64.5%) and B. germanica in clinical areas (78.1%). There was no statistically significant difference between Periplaneta americana (98.6%) and B. germanica (96.9%) regarding overall isolation rate (P > .05). However, 33 species of bacteria and 16 species of fungi were isolated from Periplaneta americana and only 23 and 12, respectively, from B. germanica. Resistance to ampicillin (13.7% to 100%), chloramphenicol (14.3% to 71.4%), tetracycline (14.3% to 73.3%), and trimethoprim-sulfamethoxazole (14.3% to 57.1%) was found in two gram-positive and five gram-negative bacteria. CONCLUSION: Because cockroach infestation occurred in more than 40% of the hospitals and nearly all of the cockroaches harbored bacteria with multidrug resistance and fungi, cockroaches may play a potential role in the epidemiology of nosocomial infections in those hospitals.     

The relationship between hand hygiene practices and nasal Staphylococcus aureus carriage in healthcare workers

Background:The nasal carriage rate of Staphylococcus aureus in healthcare workers (HCWs) is higher than the general population. Their hands serve as vectors for transmitting S.aureus colonized in the nose to patients.Objectives:To determine the rate of nasal S.aureus carriage and methicillin resistance in HCWs and to evaluate the relationship between carriage and personal risk factors and hand hygiene behaviors.Methods:The questionnaire included questions about sociodemographic characteristics, occupational and personal risk factors for S.aureus carriage, the “Hand Hygiene Belief Scale (HHBS),” and “Hand Hygiene Practices Inventory (HHPI)”. Nasal culture was taken from all participants. Presence of S.aureus, methicillin and mupirocin resistance were investigated in samples.Results:The study was carried out with 269 HCWs. The prevalence of S.aureus carriage was 20.1% (n:54). Among 54 S.aureus carriers, only one person had MRSA (0.37%). All S.aureus isolates were susceptible to mupirocin. S.aureus carriage was found to be significantly lower in the smoker group (p:0.015) and in the personnel wearing gloves during the procedures of each patient (p:0.002). S.aureus culture positivity was found to decrease significantly with increasing handwashing frequency (p:0.003). The mean HHPI score was higher in women (p:0.001). The mean HHPI score was lower in the group with nasal carriers than in non-carriers (p:0.176).Conclusion:The knowledge of hand hygiene practices, high frequency of handwashing, and wearing different gloves during the procedure of each patient decrease S.aureus nasal carriage in HCWs. In addition mupirocin is still effective in nasal S.aureus carriers.Key words: Staphylococcus aureus, nasal carriage, hand hygiene practices     

Economic and clinical impact of nosocomial meticillin-resistant Staphylococcus aureus infections in Singapore: a matched case-control study

We performed a prospective matched case-control study, with six-month follow-up for discharged subjects, to evaluate the direct clinical and financial impact of nosocomial meticillin-resistant Staphylococcus aureus (MRSA) infections in Singaporean hospitals. Consecutive nosocomial MRSA-infected cases at both tertiary public sector hospitals in Singapore were matched for age, specialty service, major surgical procedure (if applicable) and Charlson comorbidity index with up to two non-infected controls each. Chart reviews and subject interviews were performed during hospitalisation and also upon six months post-discharge for survivors. The outcomes analysed were: mortality, length of hospitalisation (LOS), healthcare-associated financial costs, and health-related quality of life. The last was evaluated via an interviewer-administered EuroQol-5D questionnaire on discharge, with conversion to a single health state summary index. Attributable outcomes were ascertained by conditional logistic and linear regression. There were 181 cases and 351 controls. MRSA infection was independently associated with in-hospital death [14.4% vs 1.4%; odds ratio (OR): 5.54; 95% confidence interval (CI): 1.63-18.79, P=0.006], longer LOS (median of 32 days vs 7 days; coefficient: 1.21; 95% CI: 1.02-1.40, P<0.001), higher hospitalisation costs (median of US$18,129.89 vs US$4,490.47; coefficient: 1.14; 95% CI: 0.93-1.35; P<0.001), higher post-discharge healthcare-associated financial costs (median of US$337.24 vs US$259.29; coefficient: 0.39; 95% CI: 0.06-0.72; P=0.021), and poorer health-related quality of life (coefficient: -0.14; 95% CI: -0.21 to -0.08; P<0.001). Outcomes were not significantly different between both hospitals. The attributable individual, institutional and societal impact of MRSA infections is considerable in Singapore. Preventing such infections will result in substantial improvements in patient outcomes and healthcare delivery.     

Role of healthcare workers in outbreaks of methicillin-resistant Staphylococcus aureus: a 10-year evaluation from a Dutch university hospital.

BACKGROUND AND OBJECTIVE: The benefit of screening healthcare workers (HCWs) at risk for methicillin-resistant Staphylococcus aureus (MRSA) carriage and furloughing MRSA-positive HCWs to prevent spread to patients is controversial. We evaluated our MRSA program for HCWs between 1992 and 2002. SETTING: A university medical center in The Netherlands, where methicillin resistance has been kept below 0.5% of all nosocomial S. aureus infections using active surveillance cultures and isolation of colonized patients. DESIGN: HCWs caring for MRSA-positive patients or patients in foreign hospitals were screened for MRSA. MRSA-positive HCWs had additional cultures, temporary exclusion from patient-related work, assessment of risk factors for persisting carriage, decolonization therapy with mupirocin intranasally and chlorhexidine baths for skin and hair, and follow-up cultures. RESULTS: Fifty-nine HCWs were colonized with MRSA. Seven of 840 screened employees contracted MRSA in foreign hospitals; 36 acquired MRSA after contact with MRSA-positive patients despite isolation precautions (attack rate per outbreak varied from less than 1% to 15%). Our hospital experienced 17 MRSA outbreaks, including 13 episodes in which HCWs were involved. HCWs were index cases of at least 4 outbreaks. In 8 outbreaks, HCWs acquired MRSA after caring for MRSA-positive patients despite isolation precautions. CONCLUSION: Postexposure screening of HCWs allowed early detection of MRSA carriage and prevention of subsequent transmission to patients. Where the MRSA prevalence is higher, the role of HCWs may be greater. In such settings, an adapted version of our program could help prevent dissemination.     

肺癌患者耐甲氧西林金黄色葡萄球菌医院感染危险因素分析

目的 分析肺癌患者医院感染耐甲氧西林葡萄球菌(MRSA)的危险因素.方法 收集2004年1月-2010年10月台州市博爱医院肿瘤科90例肺癌患者资料,其中诊断为MRSA感染病例56例为感染组,对照组为同时期同病区未感染MRSA肺癌患者34例;采用纸片扩散(K-B)法进行药敏试验;MRSA的鉴定采用CLSI 2004年指定的头孢西丁法;感染组与对照组之间比较计数资料采用t检验、卡方检验及多因素logistic回归进行分析.结果 t检验、卡方检验结果提示,年龄、混合真菌感染、机械通气、使用糖皮质激素、抗菌药物联合使用为肺癌患者医院感染MRSA的相关因素;多因素logistic回归分析结果表明,混合真菌感染(OR=12.22)、机械通气(OR=8.13)、使用糖皮质激素(OR=6.98)、抗菌药物联合使用(OR=5.18)进入回归方程.结论 混合真菌感染、机械通气、使用糖皮质激素、抗菌药物联合使用为肺癌患者医院感染MRSA的独立危险因素.