Meticillin-resistant Staphylococcus Aureus Control Research Articles

Air dispersal of meticillin-resistant Staphylococcus aureus in residential care homes for the elderly: implications for transmission during the COVID-19 pandemic

Meticillin-resistant Staphylococcus aureus (MRSA) infections are rampant in hospitals and residential care homes for the elderly (RCHEs). To analyse the prevalence of MRSA colonization among residents and staff, and degree of environmental contamination and air dispersal of MRSA in RCHEs. Epidemiological and genetic analysis by whole-genome sequencing (WGS) in 12 RCHEs in Hong Kong. During the COVID-19 pandemic (from September to October 2021), 48.7% (380/781) of RCHE residents were found to harbour MRSA at any body site, and 8.5% (8/213) of staff were nasal MRSA carriers. Among 239 environmental samples, MRSA was found in 39.0% (16/41) of randomly selected resident rooms and 31.3% (62/198) of common areas. The common areas accessible by residents had significantly higher MRSA contamination rates than those that were not accessible by residents (37.2%, 46/121 vs. 22.1%, 17/177, P=0.028). Of 124 air samples, nine (7.3%) were MRSA-positive from four RCHEs. Air dispersal of MRSA was significantly associated with operating indoor fans in RCHEs (100%, 4/4 vs. 0%, 0/8, P=0.002). WGS of MRSA isolates collected from residents, staff and environmental and air samples showed that ST 1047 (CC1) lineage 1 constituted 43.1% (66/153) of all MRSA isolates. A distinctive predominant genetic lineage of MRSA in each RCHE was observed, suggestive of intra-RCHE transmission rather than clonal acquisition from the catchment hospital. MRSA control in RCHEs is no less important than in hospitals. Air dispersal of MRSA may be an important mechanism of dissemination in RCHEs with operating indoor fans.

Joint Healthcare Infection Society (HIS) and Infection Prevention Society (IPS) guidelines for the prevention and control of meticillin-resistant Staphylococcus aureus (MRSA) in healthcare facilities

Joint Healthcare Infection Society (HIS) and Infection Prevention Society (IPS) guidelines for the prevention and control of meticillin-resistant Staphylococcus aureus (MRSA) in healthcare facilities

Epidemiology and spa-type diversity of meticillin-resistant Staphylococcus aureus in community and healthcare settings in Norway

There has been a marked increase in the incidence of meticillin-resistant Staphylococcus aureus (MRSA) during the past decade in Norway; a country with one of the lowest prevalence rates and an active 'search-and-destroy' policy applied to hospital settings. To characterize the trends of notification rates of community-associated (CA) and healthcare-associated (HA) MRSA in Norway, and explore the diversity and circulation of MRSA spa types within and outside healthcare settings. A registry-based study on notified MRSA infections and colonizations was conducted in Norway between 2006 and 2015. The diversity and abundance of CA- and HA-MRSA spa types were compared using novel ecological diversity measures (Hill numbers). During the study period, the monthly notification rate increased 6.9-fold and 1.8-fold among CA- and HA-MRSA, respectively; the increase was steeper among colonizations than infections. In both settings, the distribution of spa types was uneven, with a few dominant spa types and many singletons. The spa-type diversity of CA-MRSA was higher than HA-MRSA in terms of different types (685 vs 481), and increased during the study period. However, the diversity associated with the dominant spa types was similar and remained stable. A high overlap of spa types was estimated between the settings; spa-t002, t019 and t008 were the most common. The present findings suggest a strong connection between CA- and HA-MRSA epidemiology in Norway. If the fast-growing trend of CA-MRSA continues in the years to come, it may challenge current guidelines and infection control of MRSA in healthcare environments.

Universal screening and decolonization for control of MRSA in nursing homes: follow-up of a cluster randomized controlled trial

In 2010-11, a trial conducted in nursing homes showed no benefit of meticillin-resistant Staphylococcus aureus (MRSA) universal screening and decolonization over standard precautions to reduce the prevalence of MRSA carriage. Accordingly, no routine screening was performed from 2012. A five-year follow-up shows no new evidence supporting the intervention. Recommendations issued after trial (no screening and decolonization of MRSA residents) were retained.

Communicating the Risk of MRSA: The Role of Clinical Practice, Regulation and Other Policies in Five European Countries.

The threat posed by Meticillin-resistant Staphylococcus aureus (MRSA) has taken on an increasingly pan-European dimension. This article aims to provide an overview of the different approaches to the control of MRSA adopted in five European countries (Austria, Germany, Netherlands, Spain, and the UK) and discusses data and reporting mechanisms, regulations, guidelines, and health policy approaches with a focus on risk communication. Our hypothesis is that current infection control practices in different European countries are implicit messages that contribute to the health-related risk communication and subsequently to the public perception of risk posed by MRSA. A reporting template was used to systematically collect information from each country. Large variation in approaches was observed between countries. However, there were a number of consistent themes relevant to the communication of key information regarding MRSA, including misleading messages, inconsistencies in content and application of published guidelines, and frictions between the official communication and their adoption on provider level. The variability of recommendations within, and across, countries could be contributing to the perception of inconsistency. Having inconsistent guidelines and practices in place may also be affecting the level at which recommended behaviors are adopted. The discrepancy between the official, explicit health messages around MRSA and the implicit messages stemming from the performance of infection control measures should, therefore, be a key target for those wishing to improve risk communication.

Meticillin-resistant Staphylococcus aureus (MRSA) acquisition risk in an endemic neonatal intensive care unit with an active surveillance culture and decolonization programme

Meticillin-resistant Staphylococcus aureus (MRSA) is a leading cause of healthcare-associated infection in the neonatal intensive care unit (NICU). Decolonization may eliminate bacterial reservoirs that drive MRSA transmission. To measure the association between colonization pressure from decolonized and non-decolonized neonates and MRSA acquisition to inform use of this strategy for control of endemic MRSA. An eight-year retrospective cohort study was conducted in a level-4 NICU that used active surveillance cultures and decolonization for MRSA control. Weekly colonization pressure exposures were defined as the number of patient-days of concurrent admission with treated (decolonized) and untreated (non-decolonized) MRSA carriers in the preceding seven days. Poisson regression was used to estimate risk of incident MRSA colonization associated with colonization pressure exposures. The population-attributable fraction was calculated to assess the proportion of overall unit MRSA incidence attributable to treated or untreated patients in this setting. Every person-day increase in exposure to an untreated MRSA carrier was associated with a 6% increase in MRSA acquisition risk [relative risk (RR): 1.06; 95% confidence interval (CI): 1.01-1.11]. Risk of acquisition was not influenced by exposure to treated, isolated MRSA carriers (RR: 1.01; 95% CI: 0.98-1.04). In the context of this MRSA control programme, 22% (95% CI: 4.0-37) of MRSA acquisition could be attributed to exposures to untreated MRSA carriers. Untreated MRSA carriers were an important reservoir for transmission. Decolonized patients on contact isolation posed no detectable transmission threat, supporting the hypothesis that decolonization may reduce patient-to-patient transmission. Non-patient reservoirs may contribute to unit MRSA acquisition and require further investigation.

Postoperative infectious complications as potential negative predictors: Analysis of 600 consecutive pancreaticoduodenectomies

Meticillin-resistant Staphylococcus aureus (MRSA) is a common cause of nosocomial infection in the intensive care unit (ICU). A perception exists that ICU-acquired MRSA is associated with poor outcomes, although there are few data to support this.To determine the effect of acquiring MRSA in the ICU on 180-day mortality, and to identify risk factors associated with acquisition.Data were collected prospectively from 2007 to 2013. Patients who remained MRSA negative throughout their ICU admission were matched with patients who acquired MRSA in terms of age, Acute Physiology and Chronic Health Evaluation II score, length of ICU stay and surgical/non-surgical status.In total, 2405 patients were included in the analysis. Patients who acquired MRSA in the ICU had significantly longer ICU stays than patients who were admitted with MRSA and patients who remained MRSA negative throughout their ICU stay (P < 0.001 for both). There were no significant differences in 180-day mortality between the groups (P = 0.238). A confirmed non-MRSA infection within 48 h of ICU admission was associated with increased risk of MRSA acquisition (adjusted odds ratio 2.57, P = 0.005), and receipt of antimicrobial therapy within 48 h of ICU admission was associated with reduced risk of MRSA acquisition (adjusted odds ratio 0.38, P = 0.014).MRSA acquisition does not contribute towards mortality in critically ill patients. This raises questions regarding the cost-effectiveness of focusing infection prevention measures on the control of MRSA in ICUs. The low acquisition rate and lack of risk factors identified for MRSA in the study cohort indicate that efforts should be directed towards continual improvement of standard infection control procedures for all patients.

Differing epidemiology of two major healthcare-associated meticillin-resistant Staphylococcus aureus clones

Two meticillin-resistant Staphylococcus aureus (MRSA) clones, sequence type (ST) 22 and ST239, have successfully spread globally. Across Australia, ST22 has supplanted ST239 as the main healthcare-associated MRSA. To understand the reasons underlying this shift, the epidemiology and clinical features of infections due to ST22 and ST239 MRSA isolates from a tertiary hospital in Melbourne, Australia were compared. Over six months, consecutive MRSA isolates with clinical data were collected from specimens referred to Alfred Health Pathology (AHP). Isolates were genotyped by a multi-locus-sequence-typing-based high-resolution melting method. Three hundred and twenty-eight of 1079 (30%) S.aureus isolated by AHP were MRSA. Of these, 313 were genotyped; 78 (25%) were clonal complex (CC) 22 (representing ST22) and 142 (45%) were CC239 (representing ST239). Common clinical syndromes included skin or soft tissue, respiratory tract and osteo-articular infections. On multi-variate logistic regression, compared with CC239, CC22 was associated with older patients [adjusted odds ratio (aOR) 1.04 for each year increase, 95% confidence interval (CI) 1.02-1.07)], and patients from subacute hospitals (aOR 2.7, 95% CI 1.2-5.8) or long-term care facilities (LTCFs; aOR 5.5, 95% CI 2.0-14.5). Median time from patient admission to MRSA isolation was nine days for CC239 and one day for CC22 (P<0.01). MRSA strain epidemiology varied according to hospital unit. CC22 and CC239 MRSA have differing ecological niches. CC22 is associated with elderly patients in LTCFs, and CC239 is associated with nosocomial acquisition. Infection control strategies involving LTCFs and their residents will likely be required to achieve continued MRSA control.

Meticillin-resistant Staphylococcus aureus in the intensive care unit: its effect on outcome and risk factors for acquisition

Meticillin-resistant Staphylococcus aureus (MRSA) is a common cause of nosocomial infection in the intensive care unit (ICU). A perception exists that ICU-acquired MRSA is associated with poor outcomes, although there are few data to support this. To determine the effect of acquiring MRSA in the ICU on 180-day mortality, and to identify risk factors associated with acquisition. Data were collected prospectively from 2007 to 2013. Patients who remained MRSA negative throughout their ICU admission were matched with patients who acquired MRSA in terms of age, Acute Physiology and Chronic Health Evaluation II score, length of ICU stay and surgical/non-surgical status. In total, 2405 patients were included in the analysis. Patients who acquired MRSA in the ICU had significantly longer ICU stays than patients who were admitted with MRSA and patients who remained MRSA negative throughout their ICU stay (P < 0.001 for both). There were no significant differences in 180-day mortality between the groups (P = 0.238). A confirmed non-MRSA infection within 48 h of ICU admission was associated with increased risk of MRSA acquisition (adjusted odds ratio 2.57, P = 0.005), and receipt of antimicrobial therapy within 48 h of ICU admission was associated with reduced risk of MRSA acquisition (adjusted odds ratio 0.38, P = 0.014). MRSA acquisition does not contribute towards mortality in critically ill patients. This raises questions regarding the cost-effectiveness of focusing infection prevention measures on the control of MRSA in ICUs. The low acquisition rate and lack of risk factors identified for MRSA in the study cohort indicate that efforts should be directed towards continual improvement of standard infection control procedures for all patients.

Screening and isolation to control meticillin-resistant Staphylococcus aureus: sense, nonsense, and evidence

Screening and isolation to control meticillin-resistant Staphylococcus aureus: sense, nonsense, and evidence

Implications of targeted versus universal admission screening for meticillin-resistant Staphylococcus aureus carriage in a London hospital

Universal admission screening for meticillin-resistant Staphylococcus aureus (MRSA) has been performed in England since 2010. We evaluated the predictive performance of a regression model derived from the first year of universal screening for detecting MRSA at hospital admission. If we had used our previous targeted screening policy, 75% fewer patients (21,699 per year) would have been screened. However, this would have identified only ~55% of all MRSA carriers, 65% of healthcare-associated MRSA strains, and 40% of community-associated strains. Failing to identify ~45% of patients (262 per year) carrying MRSA at hospital admission may have implications for MRSA control.

Sustained meticillin-resistant Staphylococcus aureus control in a hyper-endemic tertiary acute care hospital with infrastructure challenges in Singapore

BackgroundMeticillin-resistant Staphylococcus aureus (MRSA) has been entrenched in Singapore hospitals since the 1980s, with an excess of 600 non-duplicate cases of infections (120 bacteraemia episodes) each year in our 995-bed university hospital. Approximately 5% of our hospital beds are used as isolation facilities.AimTo study the impact of an MRSA control bundle that was implemented via gradual geographic extension across hospital wards.MethodsThe bundle included active surveillance on admission and transfer/discharge to identify ward-based acquisition of MRSA, isolation and cohorting of MRSA-infected patients, enhanced hand hygiene initiatives, and publicly displayed feedback of MRSA acquisition and hand hygiene compliance rates. Implementation was between October 2006 and June 2010 in order to provide lead-time for the incremental development of infrastructural capacity, and to develop an ethic of infection prevention among staff. Results were analysed via interrupted time-series analysis.FindingsMRSA infections fell midway through the implementation, with MRSA bacteraemia declining from 0.26 [95% confidence interval (CI): 0.18–0.34] cases per 1000 inpatient-days in the first quarter of 2004 to 0.11 (95% CI: 0.07–0.19) cases per 1000 inpatient-days in the first quarter of 2012. MRSA acquisition rates fell a year after the programme had been fully implemented, whereas hand hygiene compliance rose significantly from 47% (95% CI: 44–49) in the first quarter of 2009 to 69% (95% CI: 68–71) in the first quarter of 2012.ConclusionSuccessful staged implementation of an MRSA bundle in a hyper-endemic setting is sustainable and represents a model that may be adapted for similar settings.

Temporal effects of infection control practices and the use of antibiotics on the incidence of MRSA

Meticillin-resistant Staphylococcus aureus (MRSA) has spread throughout the world and has become highly endemic worldwide. The need for implementing MRSA control strategies is no longer a matter of debate. To determine the temporal association between various infection control practices, the use of antibiotics and the incidence of MRSA in a 1200-bed French university hospital. A multi-variate time-series analysis, based on monthly data from a nine-year period (January 2000-December 2008), was performed in a 1200-bed French university hospital to determine the temporal association between different variables and the incidence of MRSA. MRSA colonization pressure, infection control practices and use of antibiotics were considered in the analysis. Time-series analysis showed a positive significant relationship between the incidence of hospital-acquired MRSA (HA-MRSA) and MRSA colonization pressure, the use of antibiotics (fluoroquinolones, macrolides and aminoglycosides) and the use of gloves. Conversely, a global negative correlation was observed between the incidence of HA-MRSA and the use of alcohol-based hand rub. Overall, the model explained 40.5% of the variance in the monthly incidence of MRSA. This study showed that admission of patients with MRSA, the use of antibiotics and infection control practices contributed to the incidence of HA-MRSA. This suggests that efforts should be focused on high compliance with hand disinfection. These results also raise concerns about the use of gloves when caring for patients with MRSA.

Development of a skin colonization model in gnotobiotic piglets for the study of the microbial ecology of meticillin-resistant Staphylococcus aureus ST398

Meticillin-resistant Staphylococcus aureus (MRSA) ST398 continues to spread amongst pigs and other domestic animals and man. This highlights the need for models to examine MRSA colonization and investigate control strategies. This study aimed to develop a gnotobiotic pig model and assess the potential of bacterial interference from selected coagulase-negative staphylococci (CNS) against MRSA ST398. Groups of 2-week-old piglets were atraumatically inoculated either with MRSA and/or CNS. Skin and mucosae were swabbed, and bacterial counts compared over a period of 21days. Piglets developed healthily, and bacterial populations increased similarly for both MRSA and CNS until day 32. On day 37, MRSA counts in groups with CNS reduced significantly compared with MRSA alone (P=0·03). The results showed that inoculation of piglet skin with MRSA resulted in spontaneous colonization and that MRSA ST398 has a low pathogenic potential in gnotobiotic piglets. Quantitative bacteriology indicated that initial MRSA colonization was unaffected by concurrent CNS colonization but that interference may occur over a longer period. Gnotobiotic piglets provide a reproducible model suitable for bacterial interference studies, which should be further explored as an alternative to antimicrobials in the control of MRSA.

Screening, isolation, and decolonisation strategies in the control of meticillin resistant Staphylococcus aureus in intensive care units: cost effectiveness evaluation

Objective To assess the cost effectiveness of screening, isolation, and decolonisation strategies in the control of meticillin resistant Staphylococcus aureus (MRSA) in intensive care units.Design Economic evaluation based on a...

Meticillin-resistant Staphylococcus aureus (MRSA): screening and decolonisation

Meticillin-resistant Staphylococcus aureus (MRSA) infections are of increasing importance to clinicians, public health agencies and governments. Prevention and control strategies must address sources in healthcare settings, the community and livestock. This document presents the conclusions of a European Consensus Conference on the role of screening and decolonisation in the control of MRSA infection. The conference was held in Rome on 5–6 March 2010 and was organised jointly by the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) and the International Society of Chemotherapy (ISC). In an environment where MRSA is endemic, universal or targeted screening of patients to detect colonisation was considered to be an essential pillar of any MRSA control programme, along with the option of decolonising carriers dependent on relative risk of infection, either to self or others, in a specific setting. Staff screening may be useful but is problematic as it needs to distinguish between transient carriage and longer-term colonisation. The consequences of identification of MRSA-positive staff may have important effects on morale and the ability to maintain staffing levels. The role of environmental contamination in MRSA infection is unclear, but screening may be helpful as an audit of hygiene procedures. In all situations, screening procedures and decolonisation carry a significant cost burden, the clinical value of which requires careful evaluation. European initiatives designed to provide further information on the cost/benefit value of particular strategies in the control of infection, including those involving MRSA, are in progress.

Molecular fingerprinting of meticillin-resistant Staphylococcus aureus strains isolated from patients and staff of two Iranian hospitals

Meticillin-resistant Staphylococcus aureus (MRSA) is an important cause of hospital-acquired infection. Methods for typing and epidemiological investigation of MRSA isolates have an important impact in detection of MRSA strains, source, transmission and control of these micro-organisms. The aims of this study were to study molecular diversity of MRSA isolates by randomly amplified polymorphic DNA (RAPD)-polymerase chain reaction (PCR), the surveillance efficacy of this method and determination of antibiotic resistance patterns of MRSA isolates. MRSA isolates were collected from clinical specimens and noses of 460 staff and inpatients admitted to Imam Khomeini and Paediatric Hospitals during a six-month period (2004-2005). Eighty MRSA strains, in which the presence of mecA gene had been confirmed by PCR, were subjected to RAPD-PCR using five primers and the results were summarised in a dendrogram to show the relationships between the test isolates. Antibiotic resistance patterns of MRSA isolates were also determined by disc agar diffusion method using 13 antibiotic discs according to Clinical and Laboratory Standards Institute guidelines. Forty-three RAPD-PCR profiles were detected. The test isolates were clustered into 18 taxa with 50% similarity, indicating the heterogeneity of our test isolates. MRSA isolates fell into 41 antibiotic resistance patterns. There was correlation between antibiotic resistance patterns and results of RAPD-PCR. Most of the MRSA isolates were multi-resistant.

Does hospital cleanliness correlate with meticillin-resistant Staphylococcus aureus bacteraemia rates?

Publicly available data for all National Health Service hospitals in England were used to examine whether there is a link between hospital cleanliness and rates of meticillin-resistant Staphylococcus aureus (MRSA) bacteraemia. It was not possible to demonstrate a consistent relationship between hospital cleanliness, as measured by weighted Patient Environment Action Team (PEAT) scores, and the incidence of MRSA bacteraemia. The large sizes of the data sets make it unlikely that a true correlation was missed. While a high standard of hospital cleanliness is a worthwhile goal, it is not helpful to repeatedly link MRSA control measures with improvements in standards of environmental cleanliness.

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.

A systematic review of the evidence for interventions for the prevention and control of meticillin-resistant Staphylococcus aureus (1996–2004): report to the Joint MRSA Working Party (Subgroup A)

A systematic review was undertaken of the evidence published between 1996 and 2004 on the effectiveness, and associated economic costs, of a range of interventions to prevent and control the transmission of meticillin-resistant Staphylococcus aureus (MRSA) in hospital settings. The review questions focused on screening, patient isolation, use of decolonization strategies, feedback of surveillance data, and environmental hygiene interventions. The reviewers assessed evidence from four recent systematic reviews, 24 non-experimental descriptive studies, five economic evaluations and one recently revised international guideline. The methodological quality of studies retrieved was such that there is currently insufficient high-quality evidence for infection prevention and control interventions in the fields identified for this review. However, evidence from clinically based, non-experimental studies does provide support for the continued use of a range and combination of interventions that contribute to the prevention and control of MRSA within acute hospitals and long-term-care settings. Well-conducted economic evaluations reporting the economic benefits arising from infection prevention and control interventions are lacking.