Staphylococcus aureus nasal colonization in a nursing home: eradication with mupirocin

Recent reports have emphasized an increase in both infection and colonization with methicillin-resistant Staphylococcus aureus (MRSA) in institutionalized older patients. We studied whether or not local treatment with mupirocin ointment could eliminate nasal colonization with S aureus. A total of 102 patients in a Veterans Administration nursing home were screened for S aureus nasal colonization. Thirty-nine patients (38.2%) were colonized, 18 with methicillin-sensitive Saureus (MSSA) and 21 with MRSA. Almost half of all colonized patients were in the most dependent functional category and there was a significant association of MRSA colonization, but not MSSA colonization, with poor functional status. Colonized patients were treated with mupirocin ointment applied to the anterior nares twice daily for seven days. After treatment, MSSA persisted in only two patients and MRSA in only one patient; thus, nasal colonization was eliminated in 91.4% of colonized patients. At one month and two months follow-up, 11 patients became transiently recolonized and three became persistently recolonized with S aureus. Mupirocin was well tolerated with no side effects noted. Mupirocin ointment may be useful in controlling nasal colonization with S aureus in the nursing home setting.     

The economic impact of Staphylococcus aureus infection in New York City hospitals

We modeled estimates of the incidence, deaths, and direct medical costs of Staphylococcus aureus infections in hospitalized patients in the New York City metropolitan area in 1995 by using hospital discharge data collected by the New York State Department of Health and standard sources for the costs of health care. We also examined the relative impact of methicillin-resistant versus -sensitive strains of S. aureus and of community-acquired versus nosocomial infections. S. aureus-associated hospitalizations resulted in approximately twice the length of stay, deaths, and medical costs of typical hospitalizations; methicillin-resistant and -sensitive infections had similar direct medical costs, but resistant infections caused more deaths (21% versus 8%). Community-acquired and nosocomial infections had similar death rates, but community-acquired infections appeared to have increased direct medical costs per patient ($35,300 versus $28,800). The results of our study indicate that reducing the incidence of methicillin-resistant and -sensitive nosocomial infections would reduce the societal costs of S. aureus infection.     

Methicillin-resistant Staphylococcus aureus (MRSA): a community-based prevalence survey

A prevalence survey of nasal methicillin-resistant Staphylococcus aureus (MRSA) carriage was undertaken on a random sample of adults (aged over 16) resident in the community in Birmingham, UK during 1998. Microbiological samples were taken from the anterior nares at the subjects' general practice or in their home. Information about risk factors for the acquisition of MRSA was obtained via a self-completed questionnaire. A 58% response rate (280/483) was achieved. The prevalence of nasal MRSA colonization was 1.5% [4/274, 95% confidence interval (CI) 0.03-2.9%]. Twenty-three per cent (63/274) of subjects were nasal carriers of S. aureus. Six per cent (4/63) of S. aureus isolates were MRSA and 2 of the 4 MRSA carriers reported previous contact with health facilities. The prevalence of MRSA colonization in the general adult population in Birmingham appears to be low.     

The influence of methicillin-resistant Staphylococcus aureus (MRSA) carriers in a nursery and transmission of MRSA to their households.

We examined two persistent MRSA-carrier nurses in a maternity hospital to elucidate the transmission of methicillin-resistant Staphylococcus aureus (MRSA) from healthcare providers to newborn infants and to the nurses' own families. Genotyping of the MRSA strains was performed by analyzing genomic DNA restriction length polymorphisms from pulsed-field gel electrophoresis (PFGE-RFLPs). The children of these nurses were carrying genotypically identical MRSA strains as their mother. Both MRSA carrier families remained asymptomatic over a two-year follow-up period. Eradication of nasal MRSA carriage from the two nurses resulted in declining MRSA carriage rates among infants in the nursery. Healthcare providers may become transient or persistent MRSA carriers whilst working in hospitals in which MRSA is endemic. They may then become a source of infection for patients as well as their own families. We recommend that healthcare providers should be examined for MRSA if an MRSA epidemic occurs in a hospital. The families of any such carriers should also be examined for MRSA.     

Frequency and diversity of molecular epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) isolates from patients of a South West German teaching hospital

We have determined the frequency and the genetic diversity of methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from inpatients of a South West German teaching hospital. The frequency of primary MRSA isolates remained constant over the two-year surveillance period: 108 of the total number of 1450 S. aureus isolates (7.5%) were MRSA in 2001 and the corresponding figures were 110 MRSA out of 1412 S. aureus isolates (7.8%) in 2002. Six clusters of nosocomial MRSA infection were observed during 2001 and 2002. Cluster infections involved 65 patients on four different wards. Molecular typing of the 65 cluster isolates demonstrated that 51 (79%) belonged to a single predominant clone. The remaining 14 isolates represented seven genetically unrelated MRSA clones. Molecular typing of 50 additional non-cluster, sporadic isolates demonstrated 37 different pulsed-field gel electrophoresis (PFGE) banding patterns. Our results demonstrate that primary MRSA strains from hospitalized patients show a high degree of genetic heterogeneity. In contrast, however, MRSA isolates from nosocomial clusters were mostly derived from a single predominant clone, thus indicating a significant intra-ward and intra-hospital distribution. Molecular typing methods may lead to an improved understanding of MRSA epidemiology and thus allow the establishment of effective preventive measures.     

MRSA医院感染及耐药性研究

目的 了解耐甲氧西林金黄色葡萄球菌(MRSA)医院感染及耐药性的情况.方法 采用回顾性调查方法,对医院在2008年1月-2010年12月住院期间确诊为MRSA医院感染的患者进行分析.结果 MRSA医院感染133例,149例次,其中下呼吸道感染105例,占70.5％,菌血症8例,占5.4％,表浅切口7例,占4.7％;多集中在神经外科、综合ICU和干部病房;未发现对万古霉素、替考拉宁、利奈唑胺耐药株.结论 MRSA是医院感染的重要致病菌,了解其临床分布,加强耐药监测,规范临床用药,可有效预防耐药菌的产生.     

Incidence and epidemiology of methicillin-resistant Staphylococcus aureus infection in a Saudi Arabian Hospital, 1999-2003.

During 1999-2003 in a Saudi Arabian Hospital, methicillin-resistant Staphylococcus aureus constituted 6% of all S. aureus isolates; the proportion had increased from 2% in 1999, to 9.7% in 2002, to 8% in 2003. Of all MRSA isolates, 62% represented community-acquired infection, 20.4% represented healthcare-associated infection, and 17.6% represented nosocomial infection. The proportion of community-acquired isolates increased from 41.7% in 1999 to 66.6% in 2002, and the proportion representing nosocomial infection decreased from 33% in 1999 to 19% in 2003. Isolates representing nosocomial infection showed higher rates of resistance to ciprofloxacin (76.6%), clindamycin (76.6%), erythromycin (68%) and trimethoprim-sulfamethoxazole (68%) than did isolates in the other categories (P<.001).     

Surveillance for mupirocin resistance following introduction of routine peri-operative prophylaxis with nasal mupirocin

The authors have previously described the successful use of a five-day peri-operative prophylaxis regimen using nasal mupirocin and topical triclosan (PPNMTT) to prevent methicillin-resistant Staphylococcus aureus (MRSA) infection. The present article describes the results of repeated point-prevalence surveillance for four years to determine whether mupirocin resistance has emerged in surgical units using empirical, short-term, peri-operative prophylaxis with nasal mupirocin. Before starting PPNMTT and every six months thereafter for four years, point-prevalence surveillance was performed for nasal S. aureus carriage in all patients on five orthopaedic surgery wards, one vascular surgery ward and one elderly medicine control ward. S. aureus screening and clinical isolates (surgical patients) were undertaken for low- [minimum inhibitory concentration (MIC) 8-128 mg/L] and high-level (MIC > 128 mg/L) mupirocin resistance. All isolates were phage typed to determine whether there was evidence of the spread of clonal mupirocin-resistant strains. Of 593, 139 and 206 nasal screening swabs (taken after the regimen had started) from orthopaedic, vascular and control patients, 28%, 24% and 48% (orthopaedic/vascular surgery vs elderly medicine, P < 0.001) yielded S. aureus isolates, respectively, and 12%, 11% and 30% (P < 0.001) were MRSA positive, respectively. Of the S. aureus nasal screen isolates from orthopaedic/vascular surgery and control patients, 5% and 4%, respectively, were low-level mupirocin resistant (P > 0.1). Of 286 (orthopaedic/vascular surgery) and 68 (elderly medicine) clinical S. aureus isolates obtained after the regimen had started, 7% and 9% (P > 0.1), respectively, were low-level mupirocin resistant. No high-level mupirocin-resistant isolates were isolated from mupirocin (orthopaedic/vascular surgery) or elderly medicine control ward patients. There was no trend towards increasing prevalence of low-level mupirocin resistance during the four-year study period. The results of phage typing did not support the clonal spread of resistant strains. Long-term follow-up confirmed the efficacy of PPNMTT in reducing the prevalence of nasal carriage of S. aureus and MRSA in orthopaedic and vascular surgery patients. Despite four years of use of PPNMTT, there was no evidence of sustained emergence or spread of mupirocin resistance.     

耐甲氧西林金黄色葡萄球菌医院感染及社区感染的流行特点

目的了解住院患者中耐甲氧西林金黄色葡萄球菌(MRSA)医院感染及社区感染的流行特点,为积极预防和控制MRSA的感染与传播提供科学依据。方法 2008年7月1日-2010年12月31日,由专职人员每天根据细菌培养结果按照统一的方法到病房对患者进行前瞻性调查,2005年1月1日-2008年6月30日对金黄色葡萄球菌培养阳性住院患者进行回顾性调查。结果 MRSA医院感染率为0.10‰,入院患者中MRSA社区发病的感染率为1.40‰;医院感染中MRSA感染率为70.40%,显著高于社区感染感染率为46.04%(P<0.001);MRSA感染主要发生在重症监护病房(ICU)、内科及干部病房,呼吸系统的感染;MRSA感染率最高的是ICU和干部病房,>80.0%,呼吸系统和泌尿系统的感染。结论金黄色葡萄球菌耐药状况在医院内形势依然严峻,预防与控制MRSA感染重点在ICU、内科及干部病房,主要发生在呼吸系统的感染。     

Screening strategies in surveillance and control of methicillin-resistant Staphylococcus aureus (MRSA)

With reports of hospital-acquired methicillin-resistant Staphylococcus aureus (MRSA) continuing to increase and therapeutic options decrease, infection control methods are of increasing importance. Here we investigate the relationship between surveillance and infection control. Surveillance plays two roles with respect to control: it allows detection of infected/colonized individuals necessary for their removal from the general population, and it allows quantification of control success. We develop a stochastic model of MRSA transmission dynamics exploring the effects of two screening strategies in an epidemic setting: random and on admission. We consider both hospital and community populations and include control and surveillance in a single framework. Random screening was more efficient at hospital surveillance and allowed nosocomial control, which also prevented epidemic behaviour in the community. Therefore, random screening was the more effective control strategy for both the hospital and community populations in this setting. Surveillance strategies have significant impact on both ascertainment of infection prevalence and its control.     

Nasal MRSA colonization of AIDS Patients cared for in a Brazilian university hospital.

Weekly culture surveillance was conducted over a 2-year period to determine the incidence of methicillin-resistant Staphylococcus aureus nasal colonization among acquired immunodeficiency syndrome patients cared for in a day-care unit and in an infectious diseases unit. Analysis of genomic DNA profiles showed a predominant pattern in both units.     

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.     

医院感染高发科室耐甲氧西林金黄色葡萄球菌的耐药性分析

目的 研究医院感染高发科室分离的耐甲氧西林金黄色葡萄球菌(MRSA)的耐药性,为医院MRSA感染的预防和治疗提供参考.方法 对医院感染高发科室分离的MRSA进行耐药性检测,并分析其耐药性特点等.结果 MRSA检出率为62.4％,对所选用的21种抗菌药物中的β-内酰胺类100.0％耐药,对万古霉素、利奈唑胺和替考拉宁100.0％敏感;有87.8％的红霉素耐药、克林霉素敏感MRSA株为红霉素诱导克林霉素耐药表型.结论 该次试验分离获得的MRSA表现为较为严重的多药耐药性,未发现对万古霉素耐药或中介的菌株;D-试验结果有助于临床合理选用大环内酯类抗菌药物.     

A bundle of care to reduce colorectal surgical infections: an Australian experience

Staphylococcus aureus carriage increases the risk of infection. Demographic and microbiological data from adult patients with nasal S. aureus carriage were analysed in order to define effect modifiers of this association. Predictors for growth of S. aureus from clinical cultures were identified in a case-control study using bivariate and multi-variate logistic regression analysis. Between 1 January 2005 and 1 April 2009, 645 patients with nasal S. aureus colonization and documented follow-up of ≥90 days were identified; 159 (25%) patients were found to carry meticillin-resistant S.?aureus (MRSA). The median age of patients was 58 years, and 421 (65%) were male. During the subsequent 90 days, one or more clinical cultures were positive for S. aureus in 131 patients (20%). Multi-variate analysis identified a prior history of any S. aureus positive culture [adjusted odds ratio (aOR) 2.4, 95% confidence interval (CI) 1.5-3.8; P=0.0005) as an independent predictor of subsequent S. aureus infection. MRSA colonization was a predictor of infection in patients aged >40 years (aOR 2.5, 95% CI 1.4-4.1; P=0.0004), and even more so in patients aged ≤40 years (aOR 12.4, 95% CI 3.0-51; P=0.0005). Age >40 years was an additional independent risk?factor for meticillin-susceptible S. aureus carriers (aOR 3.0, 95% CI 1.2-7.8; P=0.02) but not for MRSA carriers. Preferential screening of patients at high risk for MRSA carriage and subsequent infection, as well as the absence of a universal policy for the use of decolonization regimens, may partly explain the relatively high risk of S. aureus infection in the patient population. MRSA carriers and older patients with recurrent S. aureus positive cultures may gain the greatest benefit from routine decolonization measures.     

Prevalence of nosocomial infections in France: results of the nationwide survey in 1996. The French Prevalence Survey Study Group

To estimate the prevalence of nosocomial infections (NI) and to increase healthcare professionals' awareness of hygiene, all French hospitals were requested to participate to a national point-prevalence survey on a voluntary basis between May and June, 1996. Of the 236 334 inpatients in 830 participating hospitals, 6.7% presented with at least one nosocomial infection and 1.3% with an NI imported from another hospital. Nosocomial infection prevalence was particularly high in rehabilitation and long-term care facilities, especially for urinary tract and skin/soft tissue infections. Postoperative patients accounted for 18% of the overall population and had twice the frequency of NI as other patients. The prevalence of methicillin-resistant Staphylococcus aureus was 0.6% and accounted for 57% of all S. aureus isolated from NI. The results of this first national prevalence survey reflect the sustained efforts at combating NI over the past decade in France and provided an incentive for better definition of infection control priorities in high-risk healthcare settings.     

Nose picking and nasal carriage of Staphylococcus aureus.

OBJECTIVE: Nasal carriage of Staphylococcus aureus is an important risk factor for S. aureus infection and a reservoir for methicillin-resistant S. aureus. We investigated whether nose picking was among the determinants of S. aureus nasal carriage. SETTING AND PARTICIPANTS: The study cohort comprised 238 patients who visited the ear, nose, and throat (ENT) disease outpatient clinic of a tertiary care hospital and did not have a nose-specific complaint (defined as ENT patients) and 86 healthy hospital employees (including medical students and laboratory personnel). MEASUREMENTS: All participants completed a questionnaire on behavior regarding the nose and were screened for S. aureus nasal carriage; only ENT patients underwent nasal examination by an ear, nose, and throat physician for clinical signs of nose picking. RESULTS: Among ENT patients, nose pickers were significantly more likely than non-nose pickers to carry S. aureus (37 [53.6%] of 69 vs 60 [35.5%] of 169 patients; relative risk, 1.51 [95% confidence interval, 1.03-2.19]). Among healthy volunteers, there was a statistically significant positive correlation between the self-perceived frequency of nose picking and both the frequency of positive culture results (R=0.31; P=.004) and the load of S. aureus present in the nose (R=0.32; P=.003). CONCLUSION: Nose picking is associated with S. aureus nasal carriage. The role of nose picking in nasal carriage may well be causal in certain cases. Overcoming the habit of nose picking may aid S. aureus decolonization strategies.     

耐甲氧西林金黄色葡萄球菌医院感染调查分析

目的了解我院耐甲氧西林金黄色葡萄球菌(MRSA)的医院感染,防止医院MRSA发生和暴发流行. 方法对我院2002年1～12月发生的14例MRSA医院感染病例进行回顾性分析. 结果 2002年共分离出MRSA 26株,占金黄色葡萄球菌的27.37%,其中14株为医院感染株;MRSA医院感染者主要来自外伤(7例)、重度烧伤(4例)患者,其次是恶性肿瘤(2例)和脑出血患者(1例);其中大多数病例接受了气管插管、使用呼吸机等侵入性操作;感染部位多分布在皮肤和软组织、手术切口和下呼吸道;MRSA感染前均使用≥两种抗菌药物,其中三代头孢菌素的应用频率最高. 结论严重的基础疾病、接受侵入性操作、长期应用广谱抗菌药物可能是MRSA感染的危险因素,必须加强抗菌药物合理应用的管理和严格的消毒隔离措施.     

Optimizing delivery of care for patients with MRSA infection: focus on transitions of care

Staphylococcus aureus is among the most prevalent pathogens isolated from hospitalized patients; those infected with methicillin-resistant strains have longer hospital stays and higher total costs compared with those infected by methicillin-susceptible strains. A multidisciplinary team of health care providers, including hospitalists and other hospital-based physicians, clinical pharmacists, infectious disease specialists, infection control professionals, and case managers, is key to improving treatment and outcomes in these patients. Optimizing transitions of care for hospitalized patients with S aureus infections can improve quality and reduce total costs of care. Hospital length of stay can be shortened by initiating timely, appropriate empiric therapy and by transitioning suitable patients to outpatient antimicrobial therapy. The number of hospitalizations can be reduced by identifying patients who are suitable candidates for initial outpatient antimicrobial therapy. Consistent with good antimicrobial stewardship, the risk of resistance can be minimized by de-escalating empiric therapy to a more narrow-spectrum agent once culture and susceptibility testing results are known. There are several antimicrobial agents available for the management of S aureus infections, including methicillin-resistant S aureus. Consideration of these agents' characteristics may facilitate optimal transition of patients through health care settings.     

Nosocomial methicillin-resistant and methicillin-susceptible Staphylococcus aureus primary bacteremia: at what costs?

OBJECTIVE: To determine the attributable hospital stay and costs for nosocomial methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) primary bloodstream infections (BSIs). DESIGN: Pairwise-matched (1:1) nested case-control study. SETTING: University-based tertiary-care medical center. PATIENTS: Patients admitted between December 1993 and March 1995 were eligible. Cases were defined as patients with a primary nosocomial S. aureus BSI; controls were selected according to a priori matching criteria. MEASUREMENTS: Length of hospital stay and total and variable direct costs of hospitalization. RESULTS: The median hospital stay attributable to primary nosocomial MSSA BSI was 4 days, compared with 12 days for MRSA (P=.023). Attributable median total cost for MSSA primary nosocomial BSIs was $9,661 versus $27,083 for MRSA nosocomial infections (P=.043). CONCLUSION: Nosocomial primary BSI due to S. aureus significantly prolongs the hospital stay. Primary nosocomial BSIs due to MRSA result in an approximate threefold increase in direct cost, compared with those due to MSSA.     

Staphylococcus aureus rectal carriage and its association with infections in patients in a surgical intensive care unit and a liver transplant unit.

BACKGROUND: The role of rectal carriage of Staphylococcus aureus as a risk factor for nosocomial S. aureus infections in critically ill patients has not been fully discerned. METHODS: Nasal and rectal swabs for S. aureus were obtained on admission and weekly thereafter until discharge or death from 204 consecutive patients admitted to the surgical intensive care unit and liver transplant unit RESULTS: Overall, 49.5% (101 of 204) of the patients never harbored S. aureus, 21.6% (44 of 204) were nasal carriers only, 3.4% (7 of 204) were rectal carriers only, and 25.5% (52 of 204) were both nasal and rectal carriers. Infections due to S. aureus developed in 15.7% (32 of 204) of the patients; these included 3% (3 of 101) of the non-carriers, 18.2% (8 of 44) of the nasal carriers only, 0% (0 of 7) of the rectal carriers only, and 40.4% (21 of 52) of the patients who were both nasal and rectal carriers (P - .001). Patients with both rectal and nasal carriage were significantly more likely to develop S. aureus infection than were those with nasal carriage only (odds ratio, 3.9; 95% confidence interval, 1.18 to 7.85; P= .025). By pulsed-field gel electrophoresis, the infecting rectal and nasal isolates were clonally identical in 82% (14 of 17) of the patients with S. aureus infections. CONCLUSIONS: Rectal carriage represents an underappreciated reservoir for S. aureus in patients in the intensive care unit and liver transplant recipients. Rectal plus nasal carriage may portend a greater risk for S. aureus infections in these patients than currently realized.