Endemic Methicillin-resistant Staphylococcus Aureus Research Articles

Predictive Factors to Guide Empiric Antimicrobial Therapy of Acute Hematogenous Osteomyelitis in Children.

Acute hematogenous osteomyelitis (AHO) is a serious infection in children. Pediatric Infectious Diseases Society guidelines recommend empiric methicillin-resistant Staphylococcus aureus (MRSA) therapy in regions where MRSA accounts for more than 10-20% of all staphylococcal osteomyelitis. We sought to examine factors present at the time of admission which may predict etiology and guide empiric treatment for pediatric AHO in a region with endemic MRSA. We reviewed admissions with International Classification of Diseases 9/10 codes for AHO from 2011 to 2020 in otherwise healthy children. Medical records were reviewed for clinical and laboratory parameters present on the day of admission. Logistic regression was used to determine clinical variables independently associated with (1) MRSA infection and (2) non- Staphylococcus aureus infection. A total of 545 cases were included. An organism was identified in 77.1% of cases and S. aureus was the most common (66.2%); 18.9% of all AHO cases were MRSA. Organisms besides S. aureus were identified in 10.8% of cases. CRP >7 mg/dL, subperiosteal abscess, history of any prior skin or soft tissue infection (SSTI) and need for intensive care unit admission were independently associated with MRSA infection. Vancomycin was used as an empiric treatment in 57.6% of cases. If the above criteria were relied upon to predict MRSA AHO, empiric vancomycin use could have been reduced by 25%. Critical illness, CRP >7 mg/dL at the time of presentation, subperiosteal abscess and history of SSTI are suggestive of MRSA AHO, and could be considered when planning empiric therapy. Further work is needed to validate these findings before wider implementation.

Discontinuing MRSA and VRE contact precautions: Defining hospital characteristics and infection prevention practices predicting safe de-escalation.

To define conditions in which contact precautions can be safely discontinued for methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE). Interrupted time series. 15 acute-care hospitals. Inpatients. Contact precautions for endemic MRSA and VRE were discontinued in 12 intervention hospitals and continued at 3 nonintervention hospitals. Rates of MRSA and VRE healthcare-associated infections (HAIs) were collected for 12 months before and after. Trends in HAI rates were analyzed using Poisson regression. To predict conditions when contact precautions may be safely discontinued, selected baseline hospital characteristics and infection prevention practices were correlated with HAI rate changes, stratified by hospital. Aggregated HAI rates from intervention hospitals before and after discontinuation of contact precautions were 0.14 and 0.15 MRSA HAI per 1,000 patient days (P = .74), 0.05 and 0.05 VRE HAI per 1,000 patient days (P = .96), and 0.04 and 0.04 MRSA laboratory-identified (LabID) events per 100 admissions (P = .57). No statistically significant rate changes occurred between intervention and non-intervention hospitals. All successful hospitals had low baseline MRSA and VRE HAI rates and high hand hygiene adherence. We observed no correlations between rate changes after discontinuation and the assessed hospital characteristics and infection prevention factors, but the rate improved with higher proportion of semiprivate rooms (P = .04). Discontinuing contact precautions for MRSA/VRE did not result in increased HAI rates, suggesting that contact precautions can be safely removed from diverse hospitals, including community hospitals and those with lower proportions of private rooms. Good hand hygiene and low baseline HAI rates may be conditions permissive of safe removal of contact precautions.

Long-term impact of contact precautions cessation for Methicillin-Resistant Staphylococcus Aureus (MRSA)

Methicillin-Resistant Staphylococcus aureus (MRSA) is a major cause of healthcare-associated infections (HAI). Contact isolation has been traditionally implemented to stop transmission but its impact is increasingly questioned. A single center, retrospective, nonrandomized, observational, quasi-experimental study compared MRSA HAI rates between pre-/postdiscontinuation of MRSA contact isolation in a tertiary university hospital over 68 months. Data on primary outcomes, Central line-associated bloodstream infections and MRSA LabID bacteremia events, were analyzed by interrupted time series design using segmented Poisson regression modeling. As secondary outcomes catheter-associated urinary tract infections , ventilator-associated pneumonia , surgical site infections and hospital-associated pneumonia were compared using Fisher's exact tests. Current savings due to discontinuation were calculated based on gown use. Two hundred and ninty-five patients developed 399 HAIs. Infection rates between pre- and postinterventions were as follows: Central line-associated bloodstream infections: (0.02% vs 0.02%; P-value=.64), MRSA LabID events: (0.01% vs 0.02%; P-value=.32), hospital-associated pneumonia: (0.01% vs 0.01%; P-value=.64), catheter-associated urinary tract infections: (0% vs 0.01%; P-value=.56), ventilator-associated pneumonia: (0.01% vs 0.01%; P-value=.32), surgical site infections (0.55% vs 0.15%; P-value=.03). Savings amount to $139,228 annually. Discontinuing CP did not negatively impact endemic MRSA HAI rates between pre-postdiscontinuation periods and saved costs for isolation materials.

Reducing Isolation Burden – Infection Prevention and Control Initiated Flag Removal Process

<h3>Background</h3> The 2007 Centers for Disease Control and Infection (CDC) Guideline on Preventing Transmission of Infectious Agents in Healthcare Settings emphasized contact precautions as a key strategy to reduce transmission of multidrug resistant organisms (MDROs). To ensure that contact precautions are initiated at hospitalization, a flag is automatically generated in the electronic medical record (EMR) for patients positive for selected MDROs. The majority of these flags are for Methicillin resistant staphylococcus aureus (MRSA) and Vancomycin resistant enterococci (VRE). Recently the value of isolation for endemic MRSA and VRE has been questioned and some institutions have discontinued contact precautions for these organisms. Many states still have laws that mandate active surveillance and isolation for MRSA. To decrease burden of unnecessary isolation, Infection Prevention and Control (IPAC) implemented a process to review and manage the isolation flag in the EMR. <h3>Methods</h3> A process for flag removal was outlined in 2012. IPAC called the medical team on select patients and recommended testing to facilitate flag removal. The process was time intensive and recommendations were not followed consistently. Quality improvement tools, including value stream mapping and time studies were used to identify improvement opportunities. This resulted in creation of a nursing protocol released in tandem with the new EMR in May 2018. The protocol allowed infection preventionists to place an order for repeat testing for MRSA/VRE on eligible patients. <h3>Results</h3> Protocol use enabled IPAC to test and remove 604 MRSA and/or VRE flags between May 2018 and November 2019. Prior to initiation of the protocol, IPAC removed approximately 60 flags annually. <h3>Conclusions</h3> The EMR and nursing protocols can be leveraged to identify patients who no longer need contact precautions. This reduces the burden of isolation in hospitals that are not yet ready to eliminate contact precautions for MRSA and VRE.

The discontinuation of contact precautions for methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus: Impact upon patient adverse events and hospital operations

BackgroundContact precautions for endemic methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) are a resource-intensive intervention to reduce healthcare-associated infections, potentially impeding patient throughput and limiting bed availability to isolate...

Evaluation of contact precautions for methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus

There are limited controlled data demonstrating contact precautions (CPs) prevent methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) infections in endemic settings. We evaluated changes in hospital-acquired MRSA and VRE infections after discontinuing CPs for these organisms. This is a retrospective study done at an 800-bed teaching hospital in urban Detroit. CPs for MRSA and VRE were discontinued hospital-wide in 2013. Data on MRSA and VRE catheter-associated urinary tract infections (CAUTIs), ventilator-associated pneumonia (VAP), central line-associated bloodstream infections (CLABSIs), surgical site infections (SSIs), and hospital-acquired MRSA bacteremia (HA-MRSAB) rates were compared before and after CPs discontinuation. There were 36,907 and 40,439 patients hospitalized during the two 12-month periods: CPs and no CPs. Infection rates in the CPs and no-CPs periods were as follows: (1) MRSA infections: VAP, 0.13 versus 0.11 (P = .84); CLABSI, 0.11 versus 0.19 (P = .45); SSI, 0 versus 0.14 (P = .50); and CAUTI, 0.025 versus 0.033 (P = .84); (2) VRE infections: CAUTI, 0.27 versus 0.13 (P = .19) and CLABSI, 0.29 versus 0.3 (P = .94); and (3) HA-MRSAB rates: 0.14 versus 0.11 (P = .55), respectively. Discontinuation of CPs did not adversely impact endemic MRSA and VRE infection rates.

Contact Precautions for Endemic MRSA and VRE

This Viewpoint argues for rescission of legal mandates requiring contact precautions for any patient with methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) infection in favor and more selective and cost-effective infection control measures.

Reconsidering contact precautions for endemic methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus.

Whether contact precautions (CP) are required to control the endemic transmission of methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant Enterococcus (VRE) in acute care hospitals is controversial in light of improvements in hand hygiene, MRSA decolonization, environmental cleaning and disinfection, fomite elimination, and chlorhexidine bathing. To provide a framework for decision making around use of CP for endemic MRSA and VRE based on a summary of evidence related to use of CP, including impact on patients and patient care processes, and current practices in use of CP for MRSA and VRE in US hospitals. A literature review, a survey of Society for Healthcare Epidemiology of America Research Network members on use of CP, and a detailed examination of the experience of a convenience sample of hospitals not using CP for MRSA or VRE. Hospital epidemiologists and infection prevention experts. No high quality data support or reject use of CP for endemic MRSA or VRE. Our survey found more than 90% of responding hospitals currently use CP for MRSA and VRE, but approximately 60% are interested in using CP in a different manner. More than 30 US hospitals do not use CP for control of endemic MRSA or VRE. Higher quality research on the benefits and harms of CP in the control of endemic MRSA and VRE is needed. Until more definitive data are available, the use of CP for endemic MRSA or VRE in acute care hospitals should be guided by local needs and resources.

The role of international travel in the spread of methicillin-resistant Staphylococcus aureus.

Increasing international travel has facilitated the transmission of various multidrug-resistant bacteria-including methicillin-resistant Staphylococcus aureus (MRSA)-across continents. Individuals may acquire MRSA from the community, healthcare facilities, or even from animal exposure. Skin contact with colonized individuals, fomites, or animals during an overseas trip may result in either asymptomatic colonization or subsequent clinically significant MRSA disease. MRSA strains that harbor the Panton-Valentine leucocidin toxin are particularly associated with community transmission and may potentially have enhanced virulence resulting in serious skin and soft tissue infections or even necrotizing pneumonia. More importantly, secondary transmission events upon return from traveling have been documented, leading to potentially detrimental outbreaks within the community or the healthcare setting. We sought to review the existing literature relating to the role of various aspects of travel in the spread of MRSA. Risk factors for acquiring MRSA during travel together with the need for targeted screening of high-risk individuals will also be explored. Data for this article were identified via PubMed searches using a combination of search terms: "methicillin resistance," "MRSA," "livestock-associated MRSA," "community-associated MRSA," "travel," and "outbreak." The relevant articles were extensively perused to determine secondary sources of data. Our review of the current literature suggests that international travel plays a significant role in the transmission of MRSA, potentially contributing to the replacement of existing endemic MRSA with fitter and more transmissible strains. Therefore, selective and targeted screening of travelers with risk factors for MRSA colonization may be beneficial. Healthcare professionals and patients should be considered for screening if they were to return from endemic areas, with the former group decolonized before returning to patient care work, in order to reduce the transmission of MRSA to vulnerable patient populations.

Antidiabetic and antimicrobial activities of fractions and compounds isolated from &lt;i&gt;Berberis brevissima&lt;/i&gt; Jafri and &lt;i&gt;Berberis parkeriana&lt;/i&gt; Schneid

Methanol extracts of the roots of B. brevissima and B. parkeriana were examined for antidiabetic and antimicrobial activities. Six compounds i.e berberine, 8-oxo-berberine, dehydrocheilanthifoline, columbamine, jatrorrhizine and gluta-mic acid were isolated from the active fractions of these species for the first time. The antidiabetic activity was determined against Protein Tyrosine Phosphatase 1B (PTP 1B), a negative insulin regulator while the antimicrobial activity was performed against four bacterial strains: Mycobacterium marinum ATCC BAA535, sporadic Methicillin Resistant Staphylococcus aureus (SMRSA), endemic Methicillin Resistant Staphylococcus aureus (EMRSA) and Escherichia coli ATCC.8739 at different concentrations. Amongst the isolated compounds 8-oxo-berberine was found to be the most active antidiabetic (29 % of the positive control) while jatrorrhizine was the most active and selective antimicrobial against SMRSA and EMRSA (-1.2% of the DMSO (D) control).

Selection for qacA carriage in CC22, but not CC30, methicillin-resistant Staphylococcus aureus bloodstream infection isolates during a successful institutional infection control programme

The increasing use of chlorhexidine for methicillin-resistant Staphylococcus aureus (MRSA) decolonization raises concerns about reduced susceptibility. We evaluated the carriage of chlorhexidine resistance genes and chlorhexidine susceptibility in MRSA before and after introduction of an institutional MRSA control programme incorporating chlorhexidine-based decolonization in 2004. MRSA bloodstream infection (BSI) isolates identified between 2001 and 2009 were tested for spa and staphylococcal cassette chromosome mec type and carriage of qacA, qacB and smr. Selected isolates were tested for chlorhexidine susceptibility. Logistic regression was used to evaluate associations between clone type, carriage of resistance genes and chlorhexidine susceptibility. Temporal trends in qacA or smr carriage were analysed using separate binomial generalized linear models. Typing identified two dominant clones: CC22 (n = 224) and CC30 (n = 197). Annual MRSA BSI rates declined from 2004, although the rate of decline for CC22 was slower than for CC30. Carriage of qacA and smr and having a chlorhexidine MIC ≥2 mg/L did not increase overall amongst MRSA BSI isolates; however, qacA carriage increased in CC22 compared with in CC30 (OR, 7.21; 95% CI, 1.32-39.17). Furthermore, qacA+ CC22 isolates were more likely to have a chlorhexidine MIC ≥2 mg/L than qacA+ CC30 isolates (OR, 21.67; CI, 2.54-185.20). A successful infection control programme was associated with the selection of qacA linked with a higher chlorhexidine MIC in one dominant endemic MRSA clone (CC22), but not another (CC30). The slower reduction in the CC22 MRSA BSI rate suggests that carriage of qacA confers a selective advantage, with implications for the sustainability of decolonization practice.

Practices to prevent multidrug-resistant Acinetobacter baumannii and methicillin-resistant Staphylococcus aureus in Thailand: A national survey

Multidrug-resistant organisms (MDRO) are increasing challenges for health care institutions worldwide, and there are many factors associated with their distribution. We conducted a national survey of Thai hospitals with 1 or more intensive care units and ≥250 hospital beds to evaluate hospital characteristics and current practices to minimize the endemic burden of multidrug-resistant (MDR) Acinetobacter baumannii (AB) and methicillin-resistant Staphylococcus aureus (MRSA). Research nurses collected survey data from participating hospitals between January 1 and April 30, 2011. Data collection focused on hospital characteristics and practices to prevent endemic MDR-AB and MRSA; logistic regression analyses were used to assess associations between hospital characteristics and infection prevention control (IPC) interventions. There was an 80% survey response (N = 204) from 256 eligible hospitals. Endemic MDR-AB and MRSA were reported in 184 (90%) and 100 (40%) hospitals, respectively. The most frequently reported IPC interventions were contact isolation, hand hygiene campaigns, and antimicrobial stewardship; active surveillance, chlorhexidine gluconate bathing, and multifaceted interventions were uncommon. By multivariate analysis, having a physician as the lead infection control professional and participation in a collaborative effort to prevent MDR organisms were associated with multifaceted interventions to reduce MDR-AB, and medical school affiliation and participating in a collaborative effort to prevent MDR organisms were associated with multifaceted interventions to reduce MRSA. Multifaceted interventions to reduce, if not prevent, MDR-AB and MRSA were infrequently reported from Thai hospitals. Our survey findings provide baseline data for IPC interventions for MDR-AB and MRSA. Future efforts that correlate IPC interventions and MDRO trends will help develop evidence-based practices in these resource-limited settings.

Diversity in the antimicrobial susceptibility patterns of methicillin-resistant Staphylococcus aureus clones

Methicillin-resistant Staphylococcus aureus (MRSA) is well known for its epidemicity, with the emergence of new clones on a daily basis. Diversity in the clonal types of MRSA challenges the success of treatment, as different clones respond to different sets of antibiotics. However, the antibiotic susceptibility among the isolates within the same clones is largely unexplored. In a previous study on MRSA epidemiology in Malaysia, we identified six major clonal complexes (ST-239-CC8, ST-1-CC1, ST-188-CC1, ST-22-CC22, ST-7-CC7 and ST-1283-CC8). In the present study, we investigated the antibiotic susceptibility patterns of isolates of different clones. Three hundred and eighty-nine MRSA isolates were subjected to the disc diffusion test, oxacillin minimum inhibitory concentration (MIC) determination and assessment of the distribution of macrolide, lincosamide and streptogramin B (MLS(B)) resistance genes. Thirty-six different antibiotic profiles were observed: 30 (83.3 %) among ST-239, 2 (5.6 %) among ST-1283 and 1 (2.8 %) each for ST-1, ST-7, ST-22 and ST-188. All ST-239 (362, 9 %) isolates were multiple drug-resistant (MDR; resistant to more than three classes of antibiotics) and had oxacillin MICs >256 mg/l. Among the 385 clindamycin-resistant isolates, 375 (96.4 %) illustrated inducible resistance (D-zone-positive), while 10 (2.6 %) showed constitutive resistance. The vast majority of the macrolide-resistant isolates carried the ermA gene (95.1 %), followed by ermC (12.9 %). Diversity in the antibiotic susceptibilities of isolates within the clones emphasises the need for continuous surveillance of MDR strains to prescribe the correct antibiotic rather than empirical treatment. This will likely reduce the emergence of new endemic or epidemic resistant MRSA clones.

Quantifying Type-Specific Reproduction Numbers for Nosocomial Pathogens: Evidence for Heightened Transmission of an Asian Sequence Type 239 MRSA Clone

An important determinant of a pathogen's success is the rate at which it is transmitted from infected to susceptible hosts. Although there are anecdotal reports that methicillin-resistant Staphylococcus aureus (MRSA) clones vary in their transmissibility in hospital settings, attempts to quantify such variation are lacking for common subtypes, as are methods for addressing this question using routinely-collected MRSA screening data in endemic settings. Here we present a method to quantify the time-varying transmissibility of different subtypes of common bacterial nosocomial pathogens using routine surveillance data. The method adapts approaches for estimating reproduction numbers based on the probabilistic reconstruction of epidemic trees, but uses relative hazards rather than serial intervals to assign probabilities to different sources for observed transmission events. The method is applied to data collected as part of a retrospective observational study of a concurrent MRSA outbreak in the United Kingdom with dominant endemic MRSA clones (ST22 and ST36) and an Asian ST239 MRSA strain (ST239-TW) in two linked adult intensive care units, and compared with an approach based on a fully parametric transmission model. The results provide support for the hypothesis that the clones responded differently to an infection control measure based on the use of topical antiseptics, which was more effective at reducing transmission of endemic clones. They also suggest that in one of the two ICUs patients colonized or infected with the ST239-TW MRSA clone had consistently higher risks of transmitting MRSA to patients free of MRSA. These findings represent some of the first quantitative evidence of enhanced transmissibility of a pandemic MRSA lineage, and highlight the potential value of tailoring hospital infection control measures to specific pathogen subtypes.

A USA300 variant and other human-related methicillin-resistant Staphylococcus aureus strains infecting cats and dogs in France

To characterize methicillin-resistant Staphylococcus aureus (MRSA) clinical strains from cats and dogs in France, and to compare the clones identified with the distribution of French human MRSA. Susceptibilities to antimicrobials were assessed by disc diffusion. Resistance and virulence genes were screened using a microarray-based assay. Isolates were additionally characterized by SmaI macrorestriction analysis and spa typing. From 2006 to 2010, the proportion of MRSA infections in pets in France was low (1.8%), but most isolates (87.0%, 20/23) belonged to human clones. The most common clones were the Lyon clone (69.6%, 16/23), the livestock-associated CC398 (13.0%, 3/23) and the Geraldine clone (8.7%, 2/23). Interestingly, we report the first USA300 clone infecting a European dog, which was probably imported by a US patient. Over a 5 year period, the proportion of MRSA infections in pets appears low (<2%) in France, but the distribution of the clones mostly mirrors the epidemiology of human invasive clones. These data highlight the role of pets as both victims and reservoirs of endemic, epidemic and/or invasive MRSA.

Successful Control of Methicillin-Resistant Staphylococcus aureus in Endemic Neonatal Intensive Care Units—A 7-Year Campaign

BackgroundMethicillin-resistant Staphylococcus aureus (MRSA) is among the most important nosocomial pathogens in the intensive care unit (ICU) worldwide, including Taiwan. Since 1997, our neonatal ICUs (NICUs) had become endemic for MRSA.Methodology/Principal FindingsTo control MRSA spread in our NICUs, we implemented a series of infection control measures stepwise, including reinforcement of hand hygiene since January 2000, augmentation of aseptic care over the insertion site of central venous catheter since July 2001, introduction of alcohol-based handrubs since April 2003, surveillance culture for MRSA and cohort care for the colonized patients between March 2003 and February 2004, and surveillance culture with subsequent decolonization of MRSA between August 2005 and July 2006. After implementation of these measures, MRSA healthcare-associated infection (HAI) density reduced by 92%, from 5.47 episodes per 1000 patient-days in 1999 to 0.45 episodes per 1000 patient-days in 2006; MRSA bloodstream infection reduced from 40 cases in 1999 to only one case in 2006. Compared to those obtained during the period of surveillance culture without decolonization, both rates of MRSA colonization (8.6% vs. 41%, p<0.001) and infection (1.1% vs. 12%, p<0.001) decreased significantly during the period of surveillance and decolonization. Molecular analysis of the clinical isolates during the study period showed that the endemic clone, which dominated between 1998 and 2005, almost disappeared in 2006, while the community clones increased significantly in 2006–2007.Conclusion/SignificanceThrough infection control measures, MRSA HAIs can be successfully controlled, even in areas with high levels of endemic MRSA infections such as our NICUs.

National guidelines for decolonization of methicillin-resistant Staphylococcus aureus carriers: the implications of recent experience in the Netherlands

Screening of patients for carriage of methicillin-resistant Staphylococcus aureus (MRSA) coupled with interventions such as contact isolation is widely regarded as a means of reducing rates of MRSA infection and inter-patient transmission. Recent studies in the Netherlands have shown that introduction of a national guideline in which uncomplicated carriage is treated with mupirocin nasal ointment and chlorhexidine soap solution, and complicated carriage is treated using the same regimen supplemented with two oral antibiotics, was successful, with up to 80% of patients being decolonized. Increased success was seen in patients, particularly those with complicated carriage, whose treatment adhered closely to the guideline. As the Netherlands has a low level of MRSA, further work is required to see if this regimen will be as effective at reducing carriage in countries with higher rates of endemic MRSA, where re-colonization may be expected to occur more often.

Low risk despite high endemicity of methicillin-resistant Staphylococcus aureus infections following elective total joint arthroplasty: A 12-year experience

Background. It is unknown if low rates of arthroplasty infections due to methicillin-resistant Staphylococcus aureus (MRSA) can be achieved in a setting with endemic MRSA (30%).Methods. We performed a 12-year prospective cohort study (1996–2008) of patients undergoing elective knee and hip joint arthroplasties with long-term follow-up. Retrospective MRSA surveillance was undertaken using electronic databases.Results. A total of 6,100 total joint arthroplasties (4001 hip; 2099 knee; 441 (7%) revisions) were monitored for a total of 34,281 person-years of follow-up (median 64 months). MRSA carriage was detected in 126 (2.1%) episodes before arthroplasty and in 147 (2.4%) after arthroplasty. Seven (0.11%) deep arthroplasty infections due to MRSA were retrieved for an overall incidence of 2 episodes per 10,000 person-years. Six were primary surgical site infections, while one infection resulted from endocarditis. MRSA colonization pressure was 11,411 MRSA-positive days for a total of 138,044 patient-days (8.3%) among all orthopedic patients.Conclusion. Institution-wide MRSA endemicity does not necessarily lead to a high MRSA infection risk after elective hip and knee arthroplasty.

The role of general quality improvement measures in decreasing the burden of endemic MRSA in a medical–surgical intensive care unit

To determine whether any of several quality improvement interventions with none specifically targeting methicillin-resistant Staphylococcus aureus (MRSA) were associated with a decline in endemic MRSA prevalence in an intensive care unit (ICU) where active screening and contact isolation precautions for known MRSA colonised patients are not practised. Medical-surgical ICU with 2,000 admissions/year. 8.5-year retrospective time-series analysis. ICU re-location, antibiotic stewardship utilising computerised decision-support and infectious-diseases physician rounds, dedicated ICU infection control practitioners, alcohol-based hand rub solution (ABHRS). Regression modelling was used to evaluate trends in S. aureus prevalence density (monthly clinical isolates per 1,000 patient-days), antibiotic consumption, infection control consumables, ABHRS and their temporal relationship with MRSA prevalence. Methicillin-resistant S. aureus prevalence density decreased by 83% [95% confidence interval (CI) -68% to -91%, p < 0.001]. Rates of MRSA bacteraemia decreased 89% (95% CI -79% to -94%, p = 0.001) with no statistically significant change in methicillin-sensitive S. aureus bacteraemia. Hospital MRSA prevalence density decreased 17% (95% CI -5% to -27%, p = 0.005), suggesting that ICU was not shifting MRSA elsewhere. In ICU, broad-spectrum antibiotic use decreased by 26% (95% CI -12% to -38%, p = 0.008), coinciding with a decrease in MRSA, but time-series analysis did not show a significant association. On multivariate analysis, only ABHRS was significantly associated with a decrease in MRSA, but it was formally introduced late in the study period when MRSA was already in decline. General quality improvement measures were associated with a decrease in endemic MRSA in a high-risk setting without use of resource-intensive active surveillance and isolation practices.

Long-Term Control of Endemic Hospital-Wide Methicillin-ResistantStaphylococcus aureus(MRSA): The Impact of Targeted Active Surveillance for MRSA in Patients and Healthcare Workers

To evaluate the long-term impact of successive interventions on rates of methicillin-resistant Staphylococcus aureus (MRSA) colonization or infection and MRSA bacteremia in an endemic hospital-wide situation. Quasi-experimental, interrupted time-series analysis. The impact of the interventions was analyzed by use of segmented regression. Representative MRSA isolates were typed by use of pulsed-field gel electrophoresis. A 950-bed teaching hospital in Seville, Spain. All patients admitted to the hospital during the period from 1995 through 2008. Three successive interventions were studied: (1) contact precautions, with no active surveillance for MRSA; (2) targeted active surveillance for MRSA in patients and healthcare workers in specific wards, prioritized according to clinical epidemiology data; and (3) targeted active surveillance for MRSA in patients admitted from other medical centers. Neither the preintervention rate of MRSA colonization or infection (0.56 cases per 1,000 patient-days [95% confidence interval {CI}, 0.49-0.62 cases per 1,000 patient-days]) nor the slope for the rate of MRSA colonization or infection changed significantly after the first intervention. The rate decreased significantly to 0.28 cases per 1,000 patient-days (95% CI, 0.17-0.40 cases per 1,000 patient-days) after the second intervention and to 0.07 cases per 1,000 patient-days (95% CI, 0.06-0.08 cases per 1,000 patient-days) after the third intervention, and the rate remained at a similar level for 8 years. The MRSA bacteremia rate decreased by 80%, whereas the rate of bacteremia due to methicillin-susceptible S. aureus did not change. Eighty-three percent of the MRSA isolates identified were clonally related. All MRSA isolates obtained from healthcare workers were clonally related to those recovered from patients who were in their care. Our data indicate that long-term control of endemic MRSA is feasible in tertiary care centers. The use of targeted active surveillance for MRSA in patients and healthcare workers in specific wards (identified by means of analysis of clinical epidemiology data) and the use of decolonization were key to the success of the program.