Impact of contact and droplet precautions on the incidence of hospital-acquired methicillin-resistant Staphylococcus aureus infection.

OBJECTIVE: To evaluate the efficacy of contact and droplet precautions in reducing the incidence of hospital-acquired methicillin-resistant Staphylococcus aureus (MRSA) infections. DESIGN: Before-after study.Setting. A 439-bed, university-affiliated community hospital. METHODS: To identify inpatients infected or colonized with MRSA, we conducted surveillance of S. aureus isolates recovered from clinical culture and processed by the hospital's clinical microbiology laboratory. We then reviewed patient records for all individuals from whom MRSA was recovered. The rates of hospital-acquired MRSA infection were tabulated for each area where patients received nursing care. After a baseline period, contact and droplet precautions were implemented in all intensive care units (ICUs). Reductions in the incidence of hospital-acquired MRSA infection in ICUs led to the implementation of contact precautions in non-ICU patient care areas (hereafter, "non-ICU areas"), as well. Droplet precautions were discontinued. An analysis comparing the rates of hospital-acquired MRSA infection during different intervention periods was performed. RESULTS: The combined baseline rate of hospital-acquired MRSA infection was 10.0 infections per 1,000 patient-days in the medical ICU (MICU) and surgical ICU (SICU) and 0.7 infections per 1,000 patient-days in other ICUs. Following the implementation of contact and droplet precautions, combined rates of hospital-acquired MRSA infection in the MICU and SICU decreased to 4.3 infections per 1,000 patient-days (95% confidence interval [CI], 0.17-0.97; P=.03). There was no significant change in hospital-acquired MRSA infection rates in other ICUs. After the discontinuation of droplet precautions, the combined rate in the MICU and SICU decreased further to 2.5 infections per 1,000 patient-days. This finding was not significant (P=.43). In the non-ICU areas that had a high incidence of hospital-acquired MRSA infection, the rate prior to implementation of contact precautions was 1.3 infections per 1,000 patient-days. After the implementation of contact precautions, the rate in these areas decreased to 0.9 infections per 1,000 patient-days (95% CI, 0.47-0.94; P=.02). CONCLUSION: The implementation of contact precautions significantly decreased the rate of hospital-acquired MRSA infection, and discontinuation of droplet precautions in the ICUs led to a further reduction. Additional studies evaluating specific infection control strategies are needed.     

外科重症监护室多重耐药菌医院感染控制效果研究

目的了解通过采取综合控制措施,外科重症监护室(SICU)多重耐药菌(MDROs)医院感染控制效果。方法对2007年1月1日—2010年12月31日检验科报告的所有耐甲氧西林金黄色葡萄球菌(MRSA)、耐万古霉素肠球菌(VRE)、产超广谱β-内酰胺酶大肠埃希菌及肺炎克雷伯菌、多重耐药鲍曼不动杆菌(MDR-Ab)阳性的SICU住院患者进行调查。2008年7月1日—2010年12月31日,采用前瞻性方法调查,并对感染及定植患者采取"Bundle"控制措施(如手卫生、单间隔离、戴手套、穿隔离衣等)。2007年1月1日—2008年6月30日,对住SICU且上述5种病原体阳性患者(未采取"Bundle"控制措施)的病历进行回顾性调查,调查内容相同,分析采取"Bundle"控制措施的效果。结果 2007年1月1日—2010年12月31日SICU共收治3 526例患者,11 207患者住院日,共发生104例次MDROs感染,其中ICU相关的感染65例次(62.50%),非ICU相关的感染39例次(37.50%)。随着"Bundle"控制措施的有效落实,ICU相关感染明显下降(18.75%),以MRSA和MDR-Ab医院感染控制效果最为显著(均P<0.05)。结论 SICU内MDROs医院感染严重,通过采取"Bundle"控制措施,ICU相关感染能得到有效控制。     

外科重症监护室多重耐药菌主动筛查及定植危险因素

目的了解某院外科重症监护室（SICU）多重耐药菌（MDRO）的定植情况及其危险因素，为临床主动筛查MDRO提供依据。方法对2013年6月1日-8月31日入住该院SICU≥24 h的患者进行主动筛查，检测患者耐甲氧西林金黄色葡萄球菌（MRSA）、产超广谱β 内酰胺酶大肠埃希菌和肺炎克雷伯菌（ESBL+E.coli/Kp）定植情况，并进行相关危险因素分析。结果入住SICU≤48 h的患者MRSA及ESBL+E.coli/Kp检出率分别为11.00％、73.00％；入住SICU＞7 d者MRSA及ESBL+E.coli /Kp新增检出率分别达16.67%、44.44%。入住SICU前住院时间＞7 d［OR95%CI：4.48（1.21～16.65）］是患者入住SICU时检出MRSA的独立危险因素，APACHEⅡ评分≥16分［OR95%CI：6.36（1.47～27.54）］是患者入住SICU＞48 h检出MRSA的独立危险因素。结论入住SICU患者MDRO检出率高，随着住SICU时间的延长，MDRO的检出率不断上升。医院应开展主动筛查，及时发现MDRO定植患者，通过实施有效的隔离控制措施，降低医院感染发生。     

外科重症监护室分离MRSA的流行病学研究

目的了解某院外科重症监护室(SICU)患者分离的耐甲氧西林金黄色葡萄球菌(MRSA)与同期环境分离的MRSA的同源性,为控制MRSA的院内传播提供依据。方法对2010年8—10月SICU送检临床标本进行MRSA的分离鉴定,同时对环境进行采样检测MRSA。对分离到的MRSA菌株,应用基于细菌基因组重复序列聚合酶链反应(Rep-PCR)技术的DiversiLab系统进行同源性分析。结果 124份临床标本共分离金黄色葡萄球菌12株,经鉴定全部为MRSA。对其中10株MRSA和环境分离的3株MRSA进行同源性分析,发现9株患者来源的MRSA和3株环境来源的MRSA具有高度同源性;另1株患者来源的MRSA不同于环境来源的MRSA。结论 SICU患者分离的MRSA与环境分离的MRSA呈高度同源性,可能为同一克隆株。该SICU MRSA的院内传播较为严重。     

Methicillin-resistant Staphylococcus aureus: a questionnaire survey of 75 long-term care facilities in western New York.

OBJECTIVES: To determine the frequency of recognition of methicillin-resistant Staphylococcus aureus (MRSA) as an infection control problem and its prevalence among long-term care facilities, and to evaluate whether certain long-term care facility characteristics such as bed size, ownership, level of infection control activity, and frequency of resident transfers to acute care hospitals are related to the recognition or prevalence of MRSA in this setting. DESIGN: Questionnaire survey. SETTING: Seventy-five long-term care facilities in the 8 counties of western New York. RESULTS: Seventy-five of 81 (92.6%) long-term care facilities returned a completed questionnaire. Seventy-nine percent were considered to have a "limited" level of infection control activity (part-time infection control practitioner who spent less than 10 hours a week on infection control activities). The larger the long-term care facility, the more time was spent on infection control activities (p = .01). Seventy-two percent of the long-term care facilities screened new admissions for MRSA by reviewing culture reports; 69% of the long-term care facilities had a specific infection control policy for MRSA. Sixteen of the 75 (21%) facilities felt they had an infection control problem with MRSA. By univariate analysis, the only characteristic significantly associated with this recognition was use of nurse practitioners or physician assistants by a facility (p < .05). Eighty-one percent of the 75 long-term care facilities had identified one or more patients with MRSA in the year prior to the survey. By univariate analysis, the only characteristics that were significantly associated with the number of residents with MRSA were the monthly average number of residents transferred to acute care facilities (p = .034) and facility bed size (p = .022); there was also a trend toward increasing intensity of infection control activities (p = .085). However, facility bed size and the average number of resident transfers per month to acute care facilities were strongly associated (p = .0002). By stepwise logistic regression analysis, only bed size was an independent predictor of the number of residents with MRSA. Many long-term care facilities had tried to eradicate MRSA; ciprofloxacin was most commonly used to eradicate MRSA. CONCLUSIONS: The vast majority of the 75 long-term care facilities in the 8 counties of western New York have identified patients with MRSA, although only a minority (21%) of them actually believed that an infection control problem existed. Facility size (a surrogate for the monthly average number of resident transfers to acute care facilities) seems to be an important factor in determining the number of residents with MRSA in long-term care facilities in our geographic region. The major longitudinal studies of MRSA in such facilities have so far been done only in Veterans Affairs facilities. Further studies are needed in freestanding long-term care facilities, the largest group of long-term care facilities in the United States, to determine the epidemiology of MRSA in this setting and to develop practical and valid infection control methods for residents with MRSA.     

Methicillin-resistant Staphylococcus aureus: a 5-year review of surveillance data in a tertiary care hospital in Saudi Arabia.

BACKGROUND: Staphylococcus aureus is an important pathogen that leads to serious infections in the community and in hospitals. Evidence has shown that the prevalence of infection and colonization with drug-resistant S. aureus, such as methicillin-resistant S. aureus (MRSA) and glycopeptide intermediately susceptible S. aureus, is increasing. Authorities must be aware of the prevalence of MRSA infection and colonization in their country in order to implement and monitor infection control policies that help curtail further emergence of this pathogen. OBJECTIVES: To examine the trend of hospital-acquired MRSA infection and colonization in a tertiary care institution in Saudi Arabia during a 5-year period in order to identify specific areas at high risk for MRSA transmission, and to review our MRSA decolonization procedure and outcomes. METHODS: Surveillance data prospectively collected from January 1, 2000, through December 31, 2004, on hospital-acquired (HA) MRSA were analyzed, with an emphasis on the trend of HA-MRSA infection and colonization, areas of high transmission, risk factors, and effectiveness of the implemented decolonization policy. RESULTS: During the study period, 442 cases of HA-MRSA infection and colonization were identified. Of these, 51.2% were infections, and 48.8% were colonizations. An increasing trend in the incidence rates of infection and colonization was noticed during the study period, and most cases were identified on the surgical ward (33.3%) and medical ward (32.1%). Of the 34 infected patients who underwent systematic decolonization, 35.3% were successfully decolonized, and of the 11 who underwent topical decolonization, 63.6% were successfully decolonized. CONCLUSION: The increasing trend of HA-MRSA infections has been a noticeable global problem. We identified a gradual increase in the rates of MRSA colonization and infection in a tertiary care center Saudi Arabia and recognize the importance of abiding by strict infection control policies, including hand hygiene and proper isolation practices. Continued surveillance for MRSA and other emerging multidrug-resistant pathogens is also needed.     

Inducibility and potential role of MecA-gene-positive oxacillin-susceptible Staphylococcus aureus from colonized healthcare workers as a source for nosocomial infections

To determine the carrier rate of methicillin-susceptible mecA-positive Staphylococcus aureus (dormant MRSA) among healthcare workers (HCWs), 447 nurses and physicians from 13 general wards and intensive care units were investigated for nasal or oropharyngeal S. aureus carriage during one year whenever an MRSA patient was treated. Induction of phenotypic resistance in all mecA-positive oxacillin-susceptible aureus was attempted by 24 h exposure to oxacillin and cefotaxime. Organisms from the broth tube with the highest antibiotic concentration and visible growth after incubation were re-exposed for a total of seven repetitive exposures. Two mecA-negative oxacillin-susceptible S. aureus served as negative control. A population analysis before and after antibiotic exposure was performed. A third of the HCWs were found to be S. aureus carriers. Only three nurses were MRSA positive (0.7%). Seven isolates of dormant MRSA were isolated in six nurses and one doctor (1.6%). After four days of repetitive antibiotic exposure six of seven dormant MRSA were highly resistant to oxacillin. Resistance of the two control S. aureus without the mecA gene was not changed by repetitive antibiotic exposure. Two of the seven dormant MRSA were clonally related as shown by pulsed-field gel electrophoresis (PFGE). The PFGE pattern of one dormant MRSA (HCW) was identical to an MRSA (HCW). The pattern of another dormant MRSA was indistinguishable from an MRSA isolated from a patient who was treated at the same time on the same ward suggesting transmission from the HCW to the patient. Dormant MRSA may be isolated twice as often as MRSA from HCWs. Transmission to patients is possible, which may lead to clinical infections. It might be useful to screen methicillin-susceptible S. aureus isolates from HCWs for the mecA gene when recurrent infections with MRSA occur on a ward and a source cannot be found.     

Community-acquired methicillin-resistant Staphylococcus aureus infection in Singapore is usually "healthcare associated".

OBJECTIVE: To assess the frequency of community-acquired methicillin-resistant Staphylococcus aureus (MRSA) infections. SETTING: A teaching hospital in Singapore. METHODS: Prospectively collected surveillance data were reviewed during a 1-year period to determine the extent and origin of community-acquired MRSA infections. RESULTS: Whereas 32% of 383 MRSA infections were detected less than 48 hours after hospital admission and would, by convention, be classified as "community acquired," all but one of these were among patients who had been exposed to outpatient centers including dialysis or chemotherapy clinics, visiting nurses, community hospitals, or all three. CONCLUSIONS: With health care increasingly being delivered in an outpatient setting, community-acquired MRSA infections are often acquired in hospital-related sites and most may be more accurately described as "healthcare acquired." Infection control measures need to move beyond the traditional paradigm of acute care hospitals to effectively control the spread of resistant pathogens.     

An outbreak of Acinetobacter baumannii: the importance of cross-transmission.

OBJECTIVE: To investigate an outbreak of nosocomial infections due to multidrug-resistant (MDR) Acinetobacter baumannii and to analyze the contribution of cross-transmission in the rise in infection rates. DESIGN: Epidemiological investigation; molecular typing using pulsed-field gel electrophoresis (PFGE); matched case-control study to identify risk factors for infection. SETTNG: A 34-bed surgical intensive care unit at a tertiary-care hospital. PATIENTS: Eighteen patients who developed MDRA baumannii nosocomial infection were matched to 36 patients who were admitted to the same surgical intensive care unit (SICU) room and did not develop an infection during the outbreak period. RESULTS: Prior to the outbreak, the baseline attack rate of MDR A baumannii nosocomial infections was 3 per 100 patients per month. From February 1 through March 22, 1998, the attack rate rose to 16 per 100 patients per month, with a total of 18 infections. All isolates had indistinguishable PFGE patterns. Seventy environmental cultures were negative for MDR A baumannii. Following intense infection control education, the attack rate decreased to 4 per 100 patients per month. By conditional logistic regression, cases were exposed to a significantly higher number of patients with MDR A baumannii infections compared to controls (odds ratio, 1.1; 95% confidence interval, 1.01-1.2; P=.02), even after adjusting for length of SICU admission and exposure to antibiotics and invasive devices. CONCLUSION: Cross-transmission between patients contributed to the rise in rates of MDRA baumannii infections. A common environmental source was not detected.     

外科监护病房患者医院感染的获得及对策

了解外科监护病房普外科危重患者医院感染获得的流行病学及细菌药敏测试情况。通过对１９９４年１２月～１９９６年４月期间，连续收集普外科手术后转入外科监护１０天以上的１４例危重患者，医院感染的发病情况及细菌分离株药敏情况进行研究。资料显示ＳＩＣＵ患者医院感染的特点为多部位感染占８５．８％；发生感染的部位从高到低依次为肺部、腹腔、切口、血液、消化道、泌尿道；病原菌中Ｇ＋球菌占３５．７％，Ｇ－杆菌占５８．３％，真菌占６％；Ｇ＋球菌对万古霉素和利福平较敏感，敏感率分别为９０．１％和６９％；Ｇ－杆菌对阿米卡星和妥布霉素较敏感，敏感率分别为４４．８％和４３．１％。ＳＩＣＵ医院感染获得与患者营养不良免疫力低下、手术创伤、高频率使用侵袭性诊疗操作及广谱抗生素使用不合理有关。主要防治对策除严格无菌操作外，加强营养支持治疗及合理使用抗生素。     

A study on the transmission of MRSA among the family members including clients of visiting nurse and related infection control

PURPOSE: The purpose of the study was to clarify MRSA (methicillin-resistant Staphylococcus aureus) transmission among clients, receiving nursing care from visiting nurse stations, and family members, as well as to determine MRSA positive rates of visiting nurses themselves and their handwashing habits. METHODS: The subjects were 131 clients who had utilized 32 visiting nurse stations, and had tested MRSA positive in our previous study performed 2-5 months earlier. The presence of MRSA in the nasal passages was investigated in 15 of the 131 MRSA positive clients and the 24 family members who had agreed to cooperate. Antibiotic sensitivity tests of the involved strains of MRSA were conducted using 14 antibiotics to allow antibiotic resistance patterns to be compared. 148 nurses who worked at 18 visiting nurse stations were also screened for MRSA in their nasal passages. In addition, a self-administered questionnaire was filled in concerning their handwashing habits. RESULTS: Out of 15 clients from whom MRSA was isolated in the previous study, 9 became MRSA positive (60.0%), and this was the case for 6 family members, living with 4 of them. The antibiotic resistance patterns coincided among the family members of 3 families, suggesting MRSA transmission among the client and his/her family member(s). MRSA transmission was shown not to be influenced by the ADL (activities of daily living) of a client nor by the content or time of the care provided by family member(s). As for visiting nurses, MRSA was isolated from 1 out of 148 (detection rate: 0.7%). The practice rate for handwashing was 91.2% after visiting as compared to 22.1% before visiting, and 93.4% after care as compared to 37.5% before care; the differences were significant (P < 0.001). The most frequently used handwashing procedures included handwashing with soap, povidone iodine and other disinfectants. The practice rate were 94.9% in visiting nurse stations and 91.2% in clients' homes. There was no significant difference between the procedures in these settings. DISCUSSION: Family members who are living with MRSA carriers are in danger of MRSA transmission irrespective of the content of the care, suggesting the need to prevent spread into compromised hosts or the community. On the other hand, visiting nurses are seldom infected with MRSA, and transmission of MRSA from nurses to clients is a rare event. This study showed, however, a low rate of handwashing before client contact. The possibility of cross infection from the hands of visiting nurses to their clients therefore needs further study.     

Infection control and meticillin-resistant Staphylococcus aureus in nursing homes in Oslo

Healthcare workers (HCWs) might be important in reducing healthcare-associated infections but infected or colonised HCWs may still spread pathogenic microbes to others. Norwegian policies for infection control in healthcare environments emphasise infection control programmes for both patients and HCWs. In this study, HCWs from 42 of 55 nursing homes in Oslo participated in an investigation concerning the implementation of infection control programmes during 2006-2007. Three separate questionnaires were used: the first aimed at nursing staff (enrolled nurses and assisting staff); the second for ward sisters; and the third for institution managers. Nearly 70% of the nursing homes had policies for controlling infection and transmission of meticillin-resistant Staphylococcus aureus (MRSA). About 60% of the institutions had policies for tracing MRSA infections. Four of five ward sisters tested patients for MRSA when wounds were not healing, when admitted from hospitals overseas, when patients shared a room with an MRSA-infected patient, or if patients had ever been MRSA positive. Two of five sisters would test patients with chronic urinary tract infection or patients admitted from another hospital. Among nursing staff, one out of five had cared for MRSA-positive patients. Only 4% of the staff had worked in healthcare institutions abroad, and only a few of them had been tested for MRSA. Almost 20% of the responding nursing staff worked at several institutions at the same time.     

National hospital infection surveillance on methicillin-resistant Staphylococcus aureus

Surveillance of methicillin-resistant Staphylococcus aureus (MRSA) infections in Japan was performed in 1995 and 1996. Hospital infection rates of MRSA appear to have remained stable in recent years, and this study was undertaken to test this hypothesis. In national surveillance, the incidence of MRSA hospital infections per 100 admissions remained stable at between 0.7 and 0.8 from 1999 to 2003, with a tendency towards a slight decline. This study shows that precautions against MRSA infection in Japan may prove to be an effective preventive measure.     

Staphylococcus aureus carrier state among elderly residents of a long-term care facility

INTRODUCTION: Methicillin-resistant Staphylococcus aureus (MRSA) infections have recently become a major concern in long-term care facilities (LTCF). Patients that have been colonized with MRSA in general hospitals may introduce the organisms into LTCF, and these can become reservoirs for the pathogen. Our objective was to evaluate the rate of colonization by S aureus, especially MRSA, in elderly residents of a large LTCF, and to find factors that predispose to it. METHODS: A nasal culture was obtained from randomly selected patients in an Israeli LTCF. Inclusion criteria were absence of active infection and no antibiotic treatment in the preceding month. The carrier state was defined when two consecutive cultures were positive for S aureus. RESULTS: The study population comprised 270 patients, aged 81 +/- 9.3 years and from all types of wards. Of these, 63 (23.3%) were carriers of S aureus and 17 of those (27%) had MRSA. From univariate analysis, the carrier state was associated with antibiotic treatment or an invasive procedure in the previous 3 months, and with a prior MRSA infection. Subacute LTCF departments had a higher carrier rate than the chronic care wards. CONCLUSIONS: In this large multilevel facility, 6.2% of the patients were MRSA carriers, and came predominantly from the subacute departments, suggesting an influx from general hospitals. This information and the identification of factors associated with MRSA infection permit the development of an institutional infection control program.     

Efficacy of parenteral nutrition supplemented with glutamine dipeptide to decrease hospital infections in critically ill surgical patients

BACKGROUND: Nosocomial infections are an important cause of morbidity and mortality in the surgical intensive care unit (SICU). Clinical benefits of glutamine-supplemented parenteral nutrition may occur in hospitalized surgical patients, but efficacy data in different surgical subgroups are lacking. The objective was to determine whether glutamine-supplemented parenteral nutrition differentially affects nosocomial infection rates in selected subgroups of SICU patients. METHODS: This was a double-blind, randomized, controlled study of alanyl-glutamine dipeptide-supplemented parenteral nutrition in SICU patients requiring parenteral nutrition and SICU care after surgery for pancreatic necrosis, cardiac, vascular, or colonic surgery. Subjects (n = 59) received isocaloric/isonitrogenous parenteral nutrition, providing 1.5 g/kg/d standard glutamine-free amino acids (STD-PN) or 1.0 g/kg/d standard amino acids + 0.5 g/kg/d glutamine dipeptide (GLN-PN). Enteral feedings were advanced as tolerated. Nosocomial infections were determined until hospital discharge. RESULTS: Baseline clinical/metabolic data were similar between groups. Plasma glutamine concentrations were low in all groups and were increased by GLN-PN. GLN-PN did not alter infection rates after pancreatic necrosis surgery (17 STD-PN and 15 GLN-PN patients). In nonpancreatic surgery patients (12 STD-PN and 15 GLN-PN), GLN-PN was associated with significantly decreased total nosocomial infections (STD-PN 36 vs GLN-PN 13, P < .030), bloodstream infections (7 vs 0, P < .01), pneumonias (16 vs 6, P < .05), and infections attributed to Staphylococcus aureus (P < .01), fungi, and enteric Gram-negative bacteria (each P < .05). CONCLUSIONS: Glutamine dipeptide-supplemented parenteral nutrition did not alter infection rates following pancreatic necrosis surgery but significantly decreased infections in SICU patients after cardiac, vascular, and colonic surgery.     

Clinical significance of methicillin-resistant Staphylococcus aureus colonization in residents in community long-term-care facilities in Spain

Methicillin-resistant Staphylococcus aureus (MRSA) is highly prevalent in Spanish hospitals and community long-term-care facilities (LTCFs). This longitudinal study was performed in community LTCFs to determine whether MRSA colonization is associated with MRSA infections and overall mortality. Nasal and decubitus ulcer cultures were performed every 6 months for an 18-month period on 178 MRSA-colonized residents (86 490 patient-days) and 196 non-MRSA carriers (97 470 patient-days). Fourteen residents developed MRSA infections and 10 of these were skin and soft tissue infections. Two patients with respiratory infections required hospitalization. The incidence rate of MRSA infection was 0·12/1000 patient-days in MRSA carriers and 0·05/1000 patient-days in non-carriers (P=0·46). No difference in MRSA infection rate was found according to the duration of MRSA colonization (P=0·69). The mortality rate was 20·8% in colonized residents and 16·8% in non-carriers; four residents with MRSA infection died. Overall mortality was statistically similar in both cohorts. Our results suggest that despite a high prevalence of MRSA colonization in LTCFs, MRSA infections are neither frequent nor severe while colonized residents remain at the facility. The epidemiological impact of an MRSA reservoir is more relevant than the clinical impact of this colonization for an individual resident and supports current recommendations to control MRSA spread in community LTCFs.     

Development of a surveillance system for methicillin-resistant Staphylococcus aureus in German hospitals.

OBJECTIVE: To determine the appropriate method to calculate the rate of methicillin-resistant Staphylococcus aureus (MRSA) infection and colonization (hereafter, MRSA rates) for interhospital comparisons, such that the large number of patients who are already MRSA positive on admission is taken into account. DESIGN: A prospective, multicenter, hospital-based surveillance of MRSA-positive case patients from January through December 2004. SETTING: Data from 31 hospitals participating in the German national nosocomial infections surveillance system (KISS) were recorded during routine surveillance by the infection control team at each hospital. RESULTS: Data for 4,215 MRSA-positive case patients were evaluated. From this data, the following values were calculated. The median incidence density was 0.71 MRSA-positive case patients per 1,000 patient-days, and the median nosocomial incidence density was 0.27 patients with nosocomial MRSA infection or colonization per 1,000 patient-days (95% CI, 0.18-0.34). The median average daily MRSA burden was 1.13 MRSA patient-days per 100 patient-days (95% CI, 0.86-1.51), with the average daily MRSA burden defined as the total number of MRSA patient-days divided by the total number of patient-days times 100. The median MRSA-days-associated nosocomial MRSA infection and colonization rate, which describes the MRSA infection risk for other patients in hospitals housing large numbers of MRSA-positive patients and/or many patients who were MRSA positive on admission, was 23.1 cases of nosocomial MRSA infection and colonization per 1,000 MRSA patient-days (95% CI, 17.4-28.6). The values were also calculated for various MRSA screening levels. CONCLUSIONS: The MRSA-days-associated nosocomial MRSA rate allows investigators to assess the extent of MRSA colonization and infection at each hospital, taking into account cases that have been imported from other hospitals, as well as from the community. This information provides an appropriate incentive for hospitals to introduce further infection control measures.     

Community-associated strains of methicillin-resistant Staphylococccus aureus as the cause of healthcare-associated infection.

OBJECTIVE: Methicillin-resistant Staphylococcus aureus (MRSA) isolates from patients with community-associated infection have been described as strains genetically distinct from the strains isolated from patients with healthcare-associated infection. This study examines the hypothesis that community-associated MRSA (CA-MRSA) strains now cause serious infections in hospitalized patients. METHODS: Thirty-seven clinical MRSA isolates were randomly selected from blood isolates obtained from July 2003 through June 2004. Strains were tested for staphylococcal chromosomal cassette mec (SCCmec) type, pulsed-field gel electrophoresis (PFGE) type, and presence of Panton-Valentine leukocidin (PVL) genes. Medical records review and epidemiologic classification was performed by an investigator blinded to the results of the bacterial strain analysis. Episodes of bloodstream infection were independently classified as either community-associated or healthcare-associated infections, and bacterial isolates were independently classified as either CA-MRSA strains or healthcare-associated MRSA (HA-MRSA) strains, according to established definitions. SETTING: A tertiary care Veterans Affairs Medical Center. RESULTS: Twenty-four (65%) of 37 MRSA isolates were SCCmec type IV, a genetic type characteristic of CA-MRSA strains; 22 of these 24 isolates belonged to the CA-MRSA clone USA300 and carried PVL genes. Thirteen (35%) of the 37 strains were SCCmec type II, of which 12 were USA100-ST5 and 12 lacked PVL genes. Thirty patients (81%) had healthcare-associated infections; 18 (60%) of these 30 were infected with isolates carrying markers of CA-MRSA strains. Of 7 patients with CA-MRSA infections, 6 were infected with isolates belonging to the USA300 clone. Patients with healthcare-associated bloodstream infections were as likely to be infected with a CA-MRSA strain as patients with a community-associated infection (P = .38). CONCLUSIONS: MRSA strains with molecular characteristics of CA-MRSA strains have emerged as an important cause of serious healthcare-associated infection in our hospital.     

A purpose built MRSA cohort unit

The control of hospital-acquired infection, in particular methicillin-resistant Staphylococcus aureus (MRSA) remains a challenge. Our hospital has established a purpose built 11-bed cohort unit with on-site rehabilitation for care of patients colonized with MRSA, in an attempt to improve their quality of care. Prior to the opening of this unit a number of concerns were voiced and the aim of this study was to address these. First, to establish if patient cohorting reduces the likelihood of successful decolonization, second, to evaluate the risk of staff colonization, and finally to see if successful environmental control of MRSA is possible.A patient database was established detailing patient demographics, infection rates, eradication and reacquisition rates. Staff screening was performed weekly, at the start of a period of duty. Sixty environmental sites were screened before unit opening, at 48h, six weeks and at six months.There were 88 admissions in the first six months; 62 patients were colonized with MRSA, and 26 patients (10 surgical, 16 medical) had MRSA infections. Twenty-three of 88 patients (26%) were successfully decolonized, which compares favourably with an eradication rate of 20% for the rest of the hospital. Twenty staff members participated in weekly screening. Five staff members colonized with MRSA were detected and all were successfully decolonized. Environmental control was achieved with a combination of a daily detergent clean and a once weekly clean with phenolic disinfectant.Our preliminary data suggest that, despite cohorting patients colonized with MRSA, with proper education and supervised cleaning protocols, it is possible to control environmental MRSA load, successfully decolonize patients and limit the risk of staff colonization.     

The burden of MRSA in four German university hospitals

In the last few years, a dramatic increase of Methicillin-resistant Staphylococcus aureus (MRSA) detection in German hospitals can be recognized. Under this enormous pressure it is very important for infection control teams to assess the epidemiologic situation correctly. Therefore, a prospective multicenter hospital-based surveillance of MRSA cases was executed in four university hospitals with 1017–1333 beds in Germany. Routine surveillance data were recorded of all patients with MRSA isolates from clinical samples or screening cultures. Patients had been colonized or infected with MRSA during their hospital stay. In 2002 between 183 and 291 MRSA cases were treated in the respective hospitals (between 0.53 and 0.96 MRSA cases per 1000 patient days). Of these, 44.4% were MRSA infections. The most frequent type of MRSA infections were wound infections (56.9%) followed by pneumonia (21.0%) and bloodstream infections (15.1%). Of the infected patients 51.5% were already infected at admission. The median duration of isolation of MRSA patients in private rooms was between 11 and 16 days. Altogether 21,665 isolation days were observed in four hospitals; this means 1.52% of all patient days. On average, 9.0% of roommates were identified as MRSA carriers. Due to the high percentage of imported cases, the four university hospitals introduced a general screening for MRSA at admission in all ICUs and some further departments as well as an automatic alert system for readmitted patient with MRSA during their last hospital stay.