Healthcare-associated Methicillin-resistant Staphylococcus Aureus Infections Research Articles

Impact of discontinuation of contact precautions on surveillance- and whole genome sequencing-defined methicillin-resistant Staphylococcus aureus healthcare-associated infections.

Prior studies evaluating the impact of discontinuation of contact precautions (DcCP) on methicillin-resistant Staphylococcus aureus (MRSA) outcomes have characterized all healthcare-associated infections (HAIs) rather than those likely preventable by contact precautions. We aimed to analyze the impact of DcCP on the rate of MRSA HAI including transmission events identified through whole genome sequencing (WGS) surveillance. Quasi experimental interrupted time series. Acute care medical center. Inpatients. The effect of DcCP (use of gowns and gloves) for encounters among patients with MRSA carriage was evaluated using time series analysis of MRSA HAI rates from January 2019 through December 2022, compared to WGS-defined attributable transmission events before and after DcCP in December 2020. The MRSA HAI rate was 4.22/10,000 patient days before and 2.98/10,000 patient days after DcCP (incidence rate ratio [IRR] 0.71 [95% confidence interval 0.56-0.89]) with a significant immediate decrease (P = .001). There were 7 WGS-defined attributable transmission events before and 11 events after DcCP (incident rate ratio 0.90 [95% confidence interval 0.30-2.55]). DcCP did not result in an increase in MRSA HAI or, in WGS-defined attributable transmission events. Comprehensive analyses of the effect of transmission prevention measures should include outcomes specifically measuring transmission-associated HAI.

Active Surveillance and Contact Precautions for Preventing Methicillin-Resistant Staphylococcus aureus Healthcare-Associated Infections During the COVID-19 Pandemic.

Statistically significant decreases in methicillin-resistant Staphylococcus aureus (MRSA) healthcare-associated infections (HAIs) occurred in Veterans Affairs (VA) hospitals from 2007 to 2019 using a national policy of active surveillance (AS) for facility admissions and contact precautions for MRSA colonized (CPC) or infected (CPI) patients, but the impact of suspending these measures to free up laboratory resources for testing and conserve personal protective equipment for coronavirus disease 2019 (COVID-19) on MRSA HAI rates is not known. From July 2020 to June 2022 all 123 acute care VA hospitals nationwide were given the rolling option to suspend (or re-initiate) any combination of AS, CPC, or CPI each month, and MRSA HAIs in intensive care units (ICUs) and non-ICUs were tracked. There were 917 591 admissions, 5 225 174 patient-days, and 568 MRSA HAIs. The MRSA HAI rate/1000 patient-days in ICUs was 0.20 (95% confidence interval [CI], .15-.26) for facilities practicing "AS + CPC + CPI" compared to 0.65 (95% CI, .41-.98; P < .001) for those not practicing any of these strategies, and in non-ICUs was 0.07 (95% CI, .05-.08) and 0.12 (95% CI, .08-.19; P = .01) for the respective policies. Accounting for monthly COVID-19 facility admissions using a negative binomial regression model did not change the relationships between facility policy and MRSA HAI rates. There was no significant difference in monthly facility urinary catheter-associated infection rates, a non-equivalent dependent variable, in the policy categories in either ICUs or non-ICUs. Facility removal of MRSA prevention practices was associated with higher rates of MRSA HAIs in ICUs and non-ICUs.

Active surveillance and contact precautions for preventing MRSA healthcare-associated infections during the COVID-19 pandemic

Background: Statistically significant decreases in methicillin-resistant Staphylococcus aureus (MRSA) healthcare-associated infections (HAIs) occurred in Veterans Health Administration (VA) facilities from 2007 to 2019 using active surveillance for facility admissions and contact precautions for patients colonized (CPC) or infected (CPI) with MRSA, but the value of these interventions is controversial. Objective: To determine the impact of active surveillance, CPC, and CPI on prevention MRSA HAIs, we conducted a prospective cohort study between July 2020 and June 2022 in all 123 acute-care VA medical facilities. In April 2020, all facilities were given the option to suspend any combination of active surveillance, CPC, or CPI to free up laboratory resources for COVID-19 testing and conserve personal protective equipment. We measured MRSA HAIs (cases per 1,000 patient days) in intensive care units (ICUs) and non-ICUs by the infection control policy. Results: During the analysis period, there were 917,591 admissions, 5,225,174 patient days, and 568 MRSA HAIs. Only 20% of facilities continued all 3 MRSA infection control measures in July 2020, but this rate increased to 57% by June 2022. The MRSA HAI rate for all infection sites in non-ICUs was 0.07 (95% CI, 0.05–0.08) for facilities practicing active surveillance plus CPC plus CPI compared to 0.12 (95% CI, 0.08–0.19; P = .01) for those not practicing any of these strategies, and in ICUs the MRSA HAI rates were 0.20 (95% CI, 0.15–0.26) and 0.65 (95% CI, 0.41–0.98; P &lt; .001) for the respective policies. Similar differences were seen when the analyses were restricted to MRSA bloodstream HAIs. Accounting for monthly COVID-19 admissions to facilities over the analysis period using a negative binomial regression model did not change the relationships between facility policy and MRSA HAI rates in the ICUs or non-ICUs. There was no statistically significant difference in monthly facility urinary catheter-associated infection rates, a nonequivalent dependent variable, in the categories during the analysis period in either ICUs or non-ICUs. Conclusions: In Veterans Affairs medical centers, there were fewer MRSA HAIs when facilities practiced active surveillance and contact precautions for colonized or infected patients during the COVID-19 pandemic. The effect was greater in ICUs than non-ICUs.Disclosures: None

Impact of discontinuation of contact precautions on surveillance- and whole-genome sequencing-defined MRSA infections

Background: Current guidelines recommend contact precautions to prevent transmission of methicillin-resistant Staphylococcus aureus (MRSA) in acute-care hospitals. Prior literature demonstrates that discontinuation of contact precautions for MRSA has not been associated with an increase in carriage rates including surveillance-defined healthcare-associated infection (HAI) while horizontal infection prevention strategies are implemented. Objective: To analyze the impact of discontinuation of contact precautions on the rate of MRSA infections, including surveillance-defined HAI and transmission events identified through whole-genome sequencing (WGS) surveillance. Methods: In this single tertiary-care center, retrospective, observational, quality improvement analysis, we measured 2 MRSA HAI outcomes before and after discontinuation of contact precautions (ie, gown and gloves no longer required for care of patients with prior or current MRSA infections or colonization, effective December 2, 2020). First, we conducted a time-series analysis using linear regression modelling of NHSN reported MRSA HAI rates (January 2019–November 2022). We also calculated the frequency of WGS-confirmed MRSA transmission events before in the discontinuation of contact precautions (January 2019–August 2019) and after the discontinuation of contact precautions (January 2022–November 2022) periods. Surveillance HAI events were determined using NHSN definitions; MRSA transmission events were defined as an isolate identified ≥3 days after hospitalization or within 30 days of a healthcare exposure, genetically related by ≤15 single-nucleotide polymorphisms compared to ≥1 previously sequenced MRSA isolate. Results: We identified 171 MRSA HAIs in the 23 months before discontinuation of contact precautions, corresponding to 4.24 HAI per 10,000 patient days, and 129 HAIs in the 24 months after discontinuation of contact precautions, corresponding to 3.01 HAI per 10,000 patient days (Fig.). We detected a nonsignificant change in the trend in HAI rate before and after discontinuation of contact precautions (P = .22) as well as a significant immediate decrease in the MRSA HAI rate (P &lt; 0 .001) at the time of discontinuation of contact precautions. In the WGS analysis 8 months before discontinuation of contact precautions, 11 MRSA transmission events were confirmed, comprising 4 clusters (0.75 per 10,000 patient days). In the WGS for the 11-month analysis period after discontinuation of contact precautions, there were 23 confirmed MRSA transmission events comprising 10 clusters (1.22 per 10,000 patient days; incidence rate ratio, 1.61; 95% CI, 0.75–3.66; P = .19). Conclusions: After discontinuation of contact precautions, there was no significant increase in MRSA HAI or transmission events. Further evaluation of the individual WGS transmission clusters will be helpful to determine whether discontinuation of contact precautions led to MRSA transmission in this facility in the period after discontinuation of contact precautions.Disclosure: None

2054. Trends in Incidence and Epidemiology of Methicillin-Resistant Staphylococcus aureus Bloodstream Infection, 2005–2020

Abstract Background Methicillin-resistant Staphylococcus aureus (MRSA) is a serious antimicrobial resistance threat; prevention efforts have focused primarily on healthcare-associated MRSA infections. We assessed progress in MRSA bloodstream infection (BSI) prevention during 2005-2020. Methods MRSA BSI data were from CDC Emerging Infections Program’s active, population-based surveillance for invasive S. aureus in 17 counties in 6 states (sites). A case was defined as isolation of MRSA from a blood culture in a resident of the catchment area. Cases were considered hospital-onset (HO) if the culture was obtained &amp;gt; 3 days after hospitalization, healthcare-associated community-onset (HACO) if the culture was obtained in an outpatient setting or ≤ 3 days after hospitalization in a patient with ≥ 1 prior major healthcare exposures, or otherwise community-associated (CA). Annual incidence was calculated per 100,000 census population for each epidemiologic classification. Results MRSA BSI incidence decreased from 32.2 (per 100,000 population) in 2005 to a nadir of 15.7 in 2016, then increased during 2017-2019 to 17.0 and decreased in 2020 to 16.4. (Figure 1). HACO comprised &amp;gt; 50% of all cases throughout 2005-2020 and mirrored the pattern of overall rates. HO rates decreased from 9.2 to 2.3 during 2005-2013 and fell below CA rates starting in 2012; rates were lowest during 2017-2019 (1.8-2.1) and increased in 2020 to 2.4. CA rates remained 3.0-4.6 throughout the surveillance period; during 2015-2019, rates increased from 3.0 to 4.0, then in 2020 decreased to 3.4. All sites saw decreases in overall MRSA BSI rates by &amp;gt; 50% during 2005-2020, and HACO rates in 2020 were at least 50% of total rates for each site. However, the relative proportion of CA and HO rates during 2020 varied by site (Figure 2), with CA MRSA BSI more than twice as common as HO MRSA BSI in two sites. Figure 1.Incidence rates of methicillin-resistant Staphylococcus aureus bloodstream infection, by epidemiologic classification, in 6 Emerging Infections Program sites, 2005–2020Figure 2.Ratio of incidence (per 100,000 population) of community-associated (CA) to hospital-onset (HO) methicillin-resistant Staphylococcus aureus bloodstream infection, in 6 Emerging Infections Program sites, 2020 Conclusion MRSA BSI rates fell by more than half during the 15-year surveillance period, reflecting substantial declines in HACO and HO cases; however, the recent plateau suggests a need for additional preventive measures that restore previous progress. Increased focus on CA MRSA BSI prevention may be needed in some areas depending on local epidemiology. Disclosures Ghinwa Dumyati, MD, Pfizer: Grant/Research Support William Schaffner, MD, VBI Vaccines: Advisor/Consultant.

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.

Attributable Cost of Healthcare-Associated Methicillin-Resistant Staphylococcus aureus Infection in a Long-term Care Center.

Studies have shown that healthcare-associated infections (HAIs) due to methicillin-resistant Staphylococcus aureus (MRSA) can lead to substantial healthcare costs in acute care settings. However, little is known regarding the consequences of these infections on patients in long-term care centers (LTCCs). The purpose of this study was to estimate the attributable cost of MRSA HAIs in LTCCs within the Department of Veterans Affairs (VA). We performed a retrospective cohort study of patients admitted to VA LTCCs between 1 January 2009 and 30 September 2015. MRSA HAIs were defined as a positive clinical culture at least 48 hours after LTCC admission so as to exclude community-acquired infections. Positive cultures were further classified by site (sterile or nonsterile). We used multivariable generalized linear models and 2-part models to compare the LTCC and acute care costs between patients with and without an MRSA HAI. In our primary analysis, there was no difference in LTCC costs between patients with and without a MRSA HAI. There was, however, a significant increase in the odds of being transferred to an acute care facility (odds ratio, 4.40 [95% confidence interval {CI}, 3.40-5.67]) and in acute care costs ($9711 [95% CI, $6961-$12 462]). Our findings of high cost and increased risk of transfer from LTCC to acute care are important because they highlight the substantial clinical and economic impact of MRSA infections in this population.

Methicillin-resistant Staphylococcus aureus nasal carriage among janitors working in hospital and non-hospital areas: a comparative cross-sectional study

BackgroundNasal colonization of Methicillin-resistant Staphylococcus aureus (MRSA) plays a key role in the epidemiology and pathogenesis of both healthcare-associated and community-acquired MRSA infections in various populations. Screening of MRSA nasal colonization is important in the prevention and control of infection and may provide useful information to guide antimicrobial therapy. This study aimed to determine nasal carriage of MRSA, its antimicrobial susceptibility pattern, and associated factors among janitors working in hospital & non-hospital areas at the University of Gondar, Northwest Ethiopia.MethodsA comparative cross-sectional study was carried out in a total of 436 study participants (221 hospital and 215 non-hospital janitors) from January to May 2019. The study participants were sampled using a simple random sampling technique. Data on socio-demographic characteristics and associated factors were collected through face to face interviews using a structured questionnaire. Nasal swabs were collected and inoculated into Mannitol salt agar. MRSA was detected using cefoxitin (30 µg) disc and an antibiotic susceptibility test was done using the disc diffusion method. Data were entered and analyzed using SPSS version 20 statistical package. P value ≤ 0.05 was considered as statistically significant.ResultsThe overall prevalence of S. aureus was 101/436 [23.2%, (95% CI: 19.3–27.8)], of which, 29.4% (65/221) were isolated from hospital and 16.7% (36/215) non-hospital janitors. The prevalence of MRSA was 4.8% (21/436) [95% CI: 3.0–6.9]; of these, 8.1% (18/221) of the isolates were from the hospital and 1.4% (3/215) non-hospital janitors, while methicillin-sensitive S. aureus (MSSA) in hospital & non-hospital janitors were 49 (22.2%) and 31 (14.4%), respectively. Among the MRSA isolates, 52.4% (11/21) were multi-drug resistant. Of these, 42.9% (9/18) were isolated from hospital and 66.7% (2/3) non-hospital janitors. Hence, nasal carriage of MRSA was significantly associated with hospitalization within the preceding year (AOR = 3.15, CI = 1.13–8.71).ConclusionThe present study revealed that high MSSA and MRSA were isolated from the hospital as compared to non-hospital janitors and high rates of antibiotics resistance were recorded in the hospital janitors. Consequently, hospitalizations were significantly associated with MRSA. Accordingly, regular screening of carriers in apparently healthy janitors is required for the prevention of nosocomial infections.

Methicillin-resistant Staphylococcus aureus: epidemiology and antimicrobial susceptibility experiences from the University Hospital ‘Luigi Vanvitelli’ of Naples

ABSTRACT Methicillin-resistant Staphylococcus aureus (MRSA) is one of the important pathogens worldwide showing resistance to several widely used antibiotics. This has made the treatment of MRSA infections harder, especially due to their prevalence in the hospital setting. We evaluated the antibiotic susceptibility patterns of healthcare-associated MRSA infections with a focus on Vancomycin Intermediate S. Aureus (VISA) and macrolide-licosamide-streptogramin B (MLSB) phenotypes. A total of 417 Staphylococcus aureus (S. aureus) cases were isolated between January 2017 and December 2018, through several clinical specimens collected from the University Hospital ‘Luigi Vanvitelli’ of Naples. We identified bacterial strains using Matrix-Assisted Laser Desorption/Ionization-Time of Flight (MALDI-TOF) and antimicrobial susceptibility using Phoenix BD (Becton Dickinson, NJ, USA). Out of the total 417 S. aureus cases, 140 were MRSA (33.6%) and of these, 50% were soft tissue infections. All MRSA and Methicillin sensible S.aureus MSSA isolates were susceptible to linezolid and daptomycin. Two MRSA cases exhibited intermediate resistance to vancomycin and were of constitutive MLSB phenotype. Among the MRSA strains, 11.4% were constitutive and 43.6% were inducible MLSB phenotypes and 8.6% were macrolide-streptogramin B phenotype. This study characterized the epidemiological status, antibiotic resistance patterns, and current prevalent phenotypes of healthcare-associated MRSA. This knowledge can aid clinicians in improving the antimicrobial stewardship program by adapting appropriate guidelines for the proper use of MRSA antibacterial agents.

Trimethoprim-Sulfamethoxazole Resistance Patterns Among Methicillin-Resistant Staphylococcus aureus, 2012–2018

Background: Trimethoprim-sulfamethoxazole is commonly used for the treatment of noninvasive methicillin-resistant Staphylococcus aureus (MRSA) infections. Following a report from 2 facilities of increased trimethoprim-sulfamethoxazole resistance among MRSA infections, we assessed changes in resistance nationally and by state. Methods: We reviewed antibiotic susceptibility testing (AST) data for trimethoprim-sulfamethoxazole among S. aureus isolates associated with surgical site infections (SSIs), central-line–associated bloodstream infections (CLABSIs), and catheter-associated urinary tract infections (CAUTIs) from acute-care hospitals reported to the NHSN Device and Procedure Module from 2012 to 2018. We compared the pooled mean percentage of isolates nonsusceptible to trimethoprim-sulfamethoxazole in 2012 and 2018, stratified by MRSA and methicillin-sensitive Staphylococcus aureus (MSSA). Among MRSA isolates, we compared the percentage nonsusceptible to trimethoprim-sulfamethoxazole by healthcare-associated infection (HAI) type and state in 2012 and 2018. States with ≥20 MRSA isolates with AST reported each year were included in the state-level analysis. Results: Overall, 36,587 MRSA isolates and 46,824 MSSA isolates were reported from 2012 to 2018. Moreover, &gt;80% of MRSA and MSSA isolates had trimethoprim-sulfamethoxazole AST reported each year. Nationally, the percentage of trimethoprim-sulfamethoxazole nonsusceptible among MRSA isolates was 3.9% in 2012 compared to 6.5% in 2018 (P &lt; .001), but it was unchanged among MSSA isolates during the same period (1.1% in 2012 vs 1.4% in 2018; P = .08). Among MRSA surgical site infections (SSIs), the proportion of trimethoprim-sulfamethoxazole nonsusceptible isolates was 3.1% in 2012 versus 6.1% in 2018 (P &lt; .001) but did not change significantly for CLABSIs or CAUTIs (Fig. 1). Among the 32 states that met the inclusion criteria, there were no significant decreases, whereas 4 (12.5%) showed significant increases in the percentage of MRSA that were trimethoprim-sulfamethoxazole nonsusceptible in 2018 compared to 2012: New Jersey (2.4% in 2012 vs 19.3% in 2018; P &lt;.001); Florida (9.1% in 2012 vs 22.4% in 2018; P &lt; .001); Maryland (0.0% in 2012 vs 10.9% in 2018; P &lt; .01); and Pennsylvania (1.7% in 2012 vs 6.5% in 2018; P &lt; .001). Conclusions: Nationally, there was a modest but significant increase in the percentage of MRSA HAI isolates nonsusceptible to trimethoprim-sulfamethoxazole in 2018 compared to 2012; however, 3 of 4 states with significant increases in nonsusceptibility had substantial, potentially clinically relevant increases (&gt;10%). Ongoing characterization of MRSA isolates from Florida and New Jersey may provide insight into the underlying cause of these shifting patterns in trimethoprim-sulfamethoxazole resistance among MRSA. Healthcare personnel should select appropriate antibiotic regimens based on local resistance patterns, should monitor patients for treatment failure, and should report changes in resistance to the appropriate public health department.Funding: NoneDisclosures: None

Methicillin-resistant Staphylococcus aureus bacteraemia, 2003–2015: Comparative evaluation of changing trends in molecular epidemiology and clinical outcomes of infections

Methicillin-resistant Staphylococcus aureus (MRSA) is a prominent pathogen causing invasive infections such as bacteraemia. The continued excessive use of antibiotics to treat MRSA infections has resulted in the evolution of antimicrobial resistant of S. aureus. This study aims to perform a comparative evaluation of changing trends in molecular epidemiology of MRSA and clinical characteristics of patients. This study shows that ST22-MRSA-IV has gradually replaced ST239-MRSA-III as the predominant MRSA clone in the tertiary teaching hospital studied. Independent predictors of mortality among patients included devices in situ at the time of infection, pre-exposure to macrolides, catheter-related bloodstream infection and mono-microbial infection. Hence, our study affirmed community-associated MRSA, which was previously identified from individuals without any exposure to healthcare settings, has now emerged in healthcare settings, causing healthcare-associated MRSA infections.

559. Two Different Beasts: Comparing Epidemiology of Healthcare-Associated vs. Community-Acquired Methicillin-Resistant Staphylococcus aureus Bacteremia

BackgroundMethicillin-resistant staphylococcus aureus (MRSA) bloodstream infection (BSI) is associated with significant morbidity and mortality. Healthcare-associated (HCA) MRSA infection (occurring >48 hours after hospitalization or in those with prior healthcare exposure) has traditionally been associated with severe invasive disease, while community-associated (CA) MRSA infection (occurring within 48 hours of hospitalization and without prior healthcare exposure) has been observed in otherwise healthy individuals. We characterized the epidemiology, resistance patterns, and clinical outcomes associated with MRSA BSI over a 5 year period comparing patients with community-onset bacteremia to those with hospital onset bacteremia.MethodsWe performed a retrospective chart review of 151 MRSA bloodstream infections from 2013–2018 at the University of Alberta Hospital (Edmonton, Canada). We assessed each BSI by: classification (CA vs. HCA), presence of MRSA risk factors, source of infection, MRSA resistance, rate of ICU admission, and 30-day mortality.ResultsThe median age of all patients with MRSA BSI was 53 years (range 23–94). MRSA BSI occurred more commonly in males for both CA and HCA infection (53% and 62%). HCA-MRSA infections had a higher rate of previous MRSA colonization (64.8%) compared with CA-MRSA patients (41.7%). Injection drug use was higher in CA-MRSA infections (47% vs. 11%). The most common source of CA-BSI was bone/joint (30%) while line-associated infections were the most common in HCA-BSI. Clindamycin resistance was common (46–53% susceptible) while resistance to tetracyclines (91–97% susceptible) and trimethoprim/sulfamethoxazole (98–100% susceptible) was uncommon. HCA-MRSA BSI was associated with a higher rate of ICU admission (44% vs. 33%) and 30-day mortality (18.7% vs. 11.7%).ConclusionInvasive MRSA infection continues to be associated with significant morbidity and mortality. We found that healthcare-associated MRSA BSI was associated with a high rate of prior MRSA colonization as well as a higher rate of ICU admission and 30-day mortality. There are significant differences in the demographics of patients with CA BSI compared with HCA BSI. Interventions to prevent these infections need to be targeted to the geographic location of acquisition.Disclosures All authors: No reported disclosures.

Successful control of a methicillin-resistant Staphylococcus aureus outbreak in a burn intensive care unit by addition of universal decolonization with intranasal mupirocin to basic infection prevention measures

Methicillin-resistant Staphylococcus aureus (MRSA) is frequently implicated in health care-associated outbreaks in burn intensive care units, incurring substantial morbidity and mortality to these high-risk patients and excess costs to health care systems. MRSA health care-associated infections (HAIs) were noted before and after the implementation of basic infection prevention measures and the subsequent implementation of universal decolonization with intranasal mupirocin. Pulsed-field gel electrophoresis was used to determine the relatedness of clinical isolates. A case-control study was conducted to characterize the risk factors for MRSA HAIs. Basic interventions failed to decrease the rate of MRSA HAIs, although compliance with these interventions was high throughout the study. MRSA HAIs decreased from 8.53 HAIs per 1,000 patient days before the implementation of intranasal mupirocin to 3.61 HAIs per 1,000 patient days after the implementation of intranasal mupirocin (P = .033). Pulsed-field gel electrophoresis disclosed 10 unique clones with no large clusters. The case-control study revealed a significant association between MRSA HAIs and lengths of stay, body surface area burned, intubation, pressor requirement, leukocytosis, lactic acidosis, development of pneumonia, MRSA colonization, and death. Basic environmental and behavioral interventions fell short of controlling a low-count, sporadic, and multiclonal MRSA outbreak in the burn intensive care unit of a tertiary medical center. However, the added implementation of universal decolonization with intranasal mupirocin was effective. Burn victims with greater disease severity were at higher risk for MRSA HAIs.

The Impact of Healthcare-Associated Methicillin-Resistant Staphylococcus aureus Infections on Postdischarge Health Care Costs and Utilization across Multiple Health Care Systems.

To measure how much of the postdischarge cost and utilization attributable to methicillin-resistant Staphylococcus aureus (MRSA) health care-associated infections (HAIs) occur within the US Department of Veterans Affairs (VA) system and how much occurs outside. Health care encounters from 3 different settings and payment models: (1) within the VA; (2) outside the VA but paid for by the VA (purchased care); and (3) outside the VA and paid for by Medicare. Historical cohort study using data from admissions to VA hospitals between 2007 and 2012. We assessed the impact of a positive MRSA test result on costs and utilization during the 365days following discharge using inverse probability of treatment weights to balance covariates. Among a cohort of 152,687 hospitalized Veterans, a positive MRSA test result was associated with an overall increase of 6.6 (95 percent CI: 5.7-7.5) inpatient days and $9,237 (95 percent CI: $8,211-$10,262) during the postdischarge period. VA inpatient admissions, Medicare reimbursements, and purchased care payments accounted for 60.6 percent, 22.5 percent, and 16.9 percent of these inpatient costs. While most of the excess postdischarge health care costs associated with MRSA HAIs occurred in the VA, non-VA costs make up an important subset of the overall burden.

Racial Disparities in Invasive Methicillin-resistant Staphylococcus aureus Infections, 2005-2014.

Despite substantial attention to the individual topics, little is known about the relationship between racial disparities and antimicrobial-resistant and/or healthcare-associated infection trends, such as for methicillin-resistant Staphylococcus aureus (MRSA). We analyzed Emerging Infections Program 2005-2014 surveillance data (9 US states) to determine whether reductions in invasive MRSA incidence (isolated from normally sterile body sites) affected racial disparities in rates. Case classification included hospital-onset (HO, culture >3 days after admission), healthcare-associated community onset (HACO, culture ≤3 days after admission and dialysis, hospitalization, surgery, or long-term care residence within 1 year prior), or community-associated (CA, all others). Negative binomial regression models were used to evaluate the adjusted rate ratio (aRR) of MRSA in black patients (vs in white patients) controlling for age, sex, and temporal trends. During 2005-2014, invasive HO and HACO (but not CA) MRSA rates decreased. Despite this, blacks had higher rates for HO (aRR, 3.20; 95% confidence interval [CI], 2.35-4.35), HACO (aRR, 3.84; 95% CI, 2.94-5.01), and CA (aRR, 2.78; 95% CI, 2.30-3.37) MRSA. Limiting the analysis to chronic dialysis patients reduced, but did not eliminate, the higher HACO MRSA rates among blacks (aRR, 1.83; 95% CI, 1.72-1.96), even though invasive MRSA rates among dialysis patients decreased during 2005-2014. These racial differences did not change over time. Previous reductions in healthcare-associated MRSA infections have not affected racial disparities in MRSA rates. Improved understanding of the underlying causes of these differences is needed to develop effective prevention interventions that reduce racial disparities in MRSA infections.

Attributable Mortality of Healthcare-Associated Infections Due to Multidrug-Resistant Gram-Negative Bacteria and Methicillin-Resistant Staphylococcus Aureus

OBJECTIVE The purpose of this study was to quantify the effect of multidrug-resistant (MDR) gram-negative bacteria and methicillin-resistant Staphylococcus aureus (MRSA) healthcare-associated infections (HAIs) on mortality following infection, regardless of patient location. METHODS We conducted a retrospective cohort study of patients with an inpatient admission in the US Department of Veterans Affairs (VA) system between October 1, 2007, and November 30, 2010. We constructed multivariate log-binomial regressions to assess the impact of a positive culture on mortality in the 30- and 90-day periods following the first positive culture, using a propensity-score-matched subsample. RESULTS Patients identified with positive cultures due to MDR Acinetobacter (n=218), MDR Pseudomonas aeruginosa (n=1,026), and MDR Enterobacteriaceae (n=3,498) were propensity-score matched to 14,591 patients without positive cultures due to these organisms. In addition, 3,471 patients with positive cultures due to MRSA were propensity-score matched to 12,499 patients without positive MRSA cultures. Multidrug-resistant gram-negative bacteria were associated with a significantly elevated risk of mortality both for invasive (RR, 2.32; 95% CI, 1.85-2.92) and noninvasive cultures (RR, 1.33; 95% CI, 1.22-1.44) during the 30-day period. Similarly, patients with MRSA HAIs (RR, 2.77; 95% CI, 2.39-3.21) and colonizations (RR, 1.32; 95% CI, 1.22-1.50) had an increased risk of death at 30 days. CONCLUSIONS We found that HAIs due to gram-negative bacteria and MRSA conferred significantly elevated 30- and 90-day risks of mortality. This finding held true both for invasive cultures, which are likely to be true infections, and noninvasive infections, which are possibly colonizations. Infect Control Hosp Epidemiol 2017;38:848-856.

Eight years of decreased methicillin-resistant Staphylococcus aureus health care-associated infections associated with a Veterans Affairs prevention initiative.

Declines in methicillin-resistant Staphylococcus aureus (MRSA) health care associated infections (HAIs) were previously reported in Veterans Affairs acute care (2012), spinal cord injury (SCIU) (2011), and long-term-care facilities (LTCFs) (2012). Here we report continuing declines in infection rates in these settings through September 2015. Monthly data entered into a national database from 127 acute care facilities, 22 SCIUs, and 133 LTCFs were evaluated for trends using negative binomial regression. There were 23,153,240 intensive care unit (ICU) and non-ICU, and 1,794,234 SCIU patient-days from October 2007-September 2015, and 22,262,605 LTCF resident-days from July 2009-September 2015. Admission nasal swabbing remained >92% in all 3 venues. Admission prevalence changed from 13.2%-13.5% in acute care, from 35.1%-32.0% in SCIUs, and from 23.1%-25.0% in LTCFs during the analysis periods. Monthly HAI rates fell 87.0% in ICUs, 80.1% in non-ICUs, 80.9% in SCIUs, and 49.4% in LTCFs (all P values < .0001 for trend). During September 2015, there were 2 MRSA HAIs reported in ICUs, 20 (with 3 in SCIUs) in non-ICUs, and 31 in LTCFs nationwide. MRSA HAI rates declined significantly in acute care, SCIUs, and LTCFs over 8 years of the Veterans Affairs MRSA Prevention Initiative.

Molecular characterization of methicillin-resistant Staphylococcus aureus isolated from blood in Rio de Janeiro displaying susceptibility profiles to non-β-lactam antibiotics.

The distinction between healthcare-associated MRSA (HA-MRSA) and community-associated MRSA (CA-MRSA) infections has become increasingly blurred. We assessed the molecular characterization and antimicrobial resistance profile for MRSA isolates from blood. Most of all (81.9%) isolates are related to known HA-MRSA and CA-MRSA epidemic lineages, such as, USA300, USA400, USA600, USA800 and USA1100. This is the first multicenter study in Rio de Janeiro.

Universal decolonization with hypochlorous solution in a burn intensive care unit in a tertiary care community hospital

Infections are the leading cause of morbidity and mortality in burn patients. Patients colonized with methicillin-resistant Staphylococcus aureus (MRSA) are at higher risk of developing an invasive infection, and MRSA is endemic in many burn units. The typical decolonization regimen of mupirocin and chlorhexidine bathing is not optimal in burn patients because of chlorhexidine limitations on nonintact skin. We studied the impact of universal decolonization using mupirocin and hypochlorous acid bathing on health care-associated MRSA infections in a burn intensive care unit. We show a significant decrease in total MRSA infections.