A novel risk-adjusted metric to compare hospitals on their antibiotic-prescribing at hospital discharge.

BACKGROUND: Antibiotic overuse at hospital discharge is common, but there is no metric to evaluate hospital performance at this transition of care. We built a risk-adjusted metric for comparing hospitals on their overall post-discharge antibiotic use. METHODS: This was a retrospective study across all acute-care admissions within the Veterans Health Administration during 2018-2021. For patients discharged to home, we collected data on antibiotics and relevant covariates. We built a zero-inflated negative binomial mixed-model with two random intercepts for each hospital to predict post-discharge antibiotic exposure and length of therapy (LOT). Data were split into training and testing sets to evaluate model performance using absolute error. Hospital performance was determined by the predicted random intercepts. RESULTS: 1,804,300 patient-admissions across 129 hospitals were included. Antibiotics were prescribed to 41.5% while hospitalized and 19.5% at discharge. Median LOT among those prescribed post-discharge antibiotics was 7 (IQR 4-10). The predictive model detected post-discharge antibiotic use with fidelity, including accurate identification of any exposure (area under the precision-recall curve=0.97) and reliable prediction of post-discharge LOT (mean absolute error = 1.48). Based on this model, 39 (30.2%) hospitals prescribed antibiotics less often than expected at discharge and used shorter LOT than expected. Twenty-eight (21.7%) hospitals prescribed antibiotics more often at discharge and used longer LOT. CONCLUSION: A model using electronically-available data was able to predict antibiotic use prescribed at hospital discharge and showed that some hospitals were more successful in reducing antibiotic overuse at this transition of care. This metric may help hospitals identify opportunities for improved antibiotic stewardship at discharge.

Diagnostic Accuracy of Hospital Antibiograms in Predicting the Risk of Antimicrobial Resistance in Enterobacteriaceae Isolates: A Nationwide Multicenter Evaluation at the Veterans Health Administration.

BACKGROUND: Many clinical guidelines recommend that clinicians use antibiograms to inform empiric antimicrobial therapy. However, hospital antibiograms are typically generated by crude aggregation of microbiologic data, and little is known about an antibiogram's reliability in predicting antimicrobial resistance (AMR) risk at the patient-level. We aimed to assess the diagnostic accuracy of antibiograms as a tool for selecting empiric therapy for Escherichia coli and Klebsiella spp. for individual patients. METHODS: We retrospectively generated hospital antibiograms for the nationwide Veterans Health Administration (VHA) facilities from 2000 to 2019 using all clinical culture specimens positive for E. coli and Klebsiella spp., then assessed the diagnostic accuracy of an antibiogram to predict resistance for isolates in the following calendar year using logistic regression models and predefined 5-step interpretation thresholds. RESULTS: Among 127 VHA facilities, 1 484 038 isolates from 704 779 patients for E. coli and 671 035 isolates from 340 504 patients for Klebsiella spp. were available for analysis. For E. coli and Klebsiella spp., the discrimination abilities of hospital-level antibiograms in predicting individual patient AMR were mostly poor, with the areas under the receiver operating curve at 0.686 and 0.715 for ceftriaxone, 0.637 and 0.675 for fluoroquinolones, and 0.576 and 0.624 for trimethoprim-sulfamethoxazole, respectively. The sensitivity and specificity of the antibiogram varied widely by antimicrobial groups and interpretation thresholds with substantial trade-offs. CONCLUSIONS: Conventional hospital antibiograms for E. coli and Klebsiella spp. have limited performance in predicting AMR for individual patients, and their utility in guiding empiric therapy may be low.

Effectiveness of Ultraviolet-C Disinfection on Hospital-Onset Gram-Negative Rod Bloodstream Infection: A Nationwide Stepped-Wedge Time-Series Analysis.

BACKGROUND: The effectiveness of enhanced terminal room cleaning with ultraviolet C (UV-C) disinfection in reducing gram-negative rod (GNR) infections has not been well evaluated. We assessed the association of implementation of UV-C disinfection systems with incidence rates of hospital-onset (HO) GNR bloodstream infection (BSI). METHODS: We obtained information regarding UV-C use and the timing of implementation through a survey of all Veterans Health Administration (VHA) hospitals providing inpatient acute care. Episodes of HO-GNR BSI were identified between January 2010 and December 2018. Bed days of care (BDOC) was used as the denominator. Over-dispersed Poisson regression models were fitted with hospital-specific random intercept, UV-C disinfection use for each month, baseline trend, and seasonality as explanatory variables. Hospitals without UV-C use were also included to the analysis as a nonequivalent concurrent control group. RESULTS: Among 128 VHA hospitals, 120 provided complete survey responses with 40 reporting implementations of UV-C systems. We identified 13 383 episodes of HO-GNR BSI and 24 141 378 BDOC. UV-C use was associated with a lower incidence rate of HO-GNR BSI (incidence rate ratio: 0.813; 95% confidence interval: .656-.969; P = .009). There was wide variability in the effect size of UV-C disinfection use among hospitals. CONCLUSIONS: In this large quasi-experimental analysis within the VHA System, enhanced terminal room cleaning with UV-C disinfection was associated with an approximately 19% lower incidence of HO-GNR BSI, with wide variability in effectiveness among hospitals. Further studies are needed to identify the optimal implementation strategy to maximize the effectiveness of UV-C disinfection technology.

Days of Antibiotic Spectrum Coverage: A Novel Metric for Inpatient Antibiotic Consumption.

BACKGROUND: Days of therapy (DOT), the most widely used benchmarking metric for antibiotic consumption, may not fully measure stewardship efforts to promote use of narrow-spectrum agents and may inadvertently discourage the use of combination regimens when single-agent alternatives have greater adverse effects. To overcome the limitations of DOT, we developed a novel metric, days of antibiotic spectrum coverage (DASC), and compared hospital performances using this novel metric with DOT. METHODS: We evaluated 77 antibiotics in 16 categories of antibacterial activity to develop our spectrum scoring system. DASC was then calculated as cumulative daily antibiotic spectrum coverage (ASC) scores. To compare hospital benchmarking using DOT and DASC, we conducted a retrospective cohort study of adult patients admitted to acute care units within the Veterans Health Administration system in 2018. Antibiotic administration data were aggregated to calculate each hospital's DOT and DASC per 1000 days present (DP) for ranking. RESULTS: The ASC score for each antibiotic ranged from 2 to 15. There was little correlation between DOT per 1000 DP and DASC per DOT, indicating that lower antibiotic consumption at a hospital does not necessarily mean more frequent use of narrow-spectrum antibiotics. The differences in each hospital's ranking between DOT and DASC per 1000 DP ranged from -29.0% to 25.0%, respectively, with 27 hospitals (21.8%) having differences >10%. CONCLUSIONS: We propose a novel composite metric for antibiotic stewardship, DASC, that combines consumption and spectrum as a potential replacement for DOT. Further studies are needed to evaluate whether benchmarking using the DASC will improve evaluations of stewardship.

Factors That Affect Legionella Positivity in Healthcare Building Water Systems from a Large, National Environmental Surveillance Initiative.

Legionella growth in healthcare building water systems can result in legionellosis, making water management programs (WMPs) important for patient safety. However, knowledge is limited on Legionella prevalence in healthcare buildings. A dataset of quarterly water testing in Veterans Health Administration (VHA) healthcare buildings was used to examine national environmental Legionella prevalence from 2015 to 2018. Bayesian hierarchical logistic regression modeling assessed factors influencing Legionella positivity. The master dataset included 201,146 water samples from 814 buildings at 168 VHA campuses. Overall Legionella positivity over the 4 years decreased from 7.2 to 5.1%, with the odds of a Legionella-positive sample being 0.94 (0.90-0.97) times the odds of a positive sample in the previous quarter for the 16 quarters of the 4 year period. Positivity varied considerably more at the medical center campus level compared to regional levels or to the building level where controls are typically applied. We found higher odds of Legionella detection in older buildings (OR 0.92 [0.86-0.98] for each more recent decade of construction), in taller buildings (OR 1.20 [1.13-1.27] for each additional floor), in hot water samples (O.R. 1.21 [1.16-1.27]), and in samples with lower residual biocide concentrations. This comprehensive healthcare building review showed reduced Legionella detection in the VHA healthcare system over time. Insights into factors associated with Legionella positivity provide information for healthcare systems implementing WMPs and for organizations setting standards and regulations.

Temporal Trends of Candidemia Incidence Rates and Potential Contributions of Infection Control Initiatives Over 18 Years Within the United States Veterans Health Administration System: A Joinpoint Time-Series Analysis.

BACKGROUND: Candidemia is one of the most common causes of nosocomial bloodstream infections, but the impacts of factors affecting its incidence have not been evaluated. METHODS: We analyzed a retrospective cohort of all candidemia patients at 130 acute care hospitals in the Veterans Health Administration (VHA) system from January 2000 through December 2017. Cases were classified as hospital-onset (HO) and non-hospital-onset (NHO). We used Joinpoint regression analysis to assess temporal associations between significant changes in candidemia incidence rates and guidelines or horizontal infection control (IC) interventions. RESULTS: Over 18 years, 17 661 candidemia episodes were identified. Incidence rates of HO cases were increasing until the mid-2000s, followed by a sustained decline, while NHO cases showed a steady decline. The first change in HO candidemia incidence rates (August 2004 [95% confidence interval {CI}, February 2003-April 2005]) was preceded by the publication of catheter-related bloodstream infection (CRBSI) prevention guidelines and the CRBSI surveillance initiation. The second (September 2007 [95% CI, September 2006-June 2009]) had close temporal proximity to the expansion of IC resources within the VHA system. Collectively, these trend changes resulted in a 77.1% reduction in HO candidemia incidence rates since its peak in 2004. CONCLUSIONS: A substantial and sustained systemwide reduction in candidemia incidence rates was observed after the publication of guidelines, VHA initiatives about CRBSI reporting and education on CRBSI prevention, and the systemwide expansion of IC resources.

Antibiotic Stewardship Implementation and Antibiotic Use at Hospitals With and Without On-site Infectious Disease Specialists.

BACKGROUND: Many US hospitals lack infectious disease (ID) specialists, which may hinder antibiotic stewardship efforts. We sought to compare patient-level antibiotic exposure at Veterans Health Administration (VHA) hospitals with and without an on-site ID specialist, defined as an ID physician and/or ID pharmacist. METHODS: This retrospective VHA cohort included all acute-care patient admissions during 2016. A mandatory survey was used to identify hospitals' antibiotic stewardship processes and their access to an on-site ID specialist. Antibiotic use was quantified as days of therapy per days present and categorized based on National Healthcare Safety Network definitions. A negative binomial regression model with risk adjustment was used to determine the association between presence of an on-site ID specialist and antibiotic use at the level of patient admissions. RESULTS: Eighteen of 122 (14.8%) hospitals lacked an on-site ID specialist; there were 525 451 (95.8%) admissions at ID hospitals and 23 007 (4.2%) at non-ID sites. In the adjusted analysis, presence of an ID specialist was associated with lower total inpatient antibacterial use (odds ratio, 0.92; 95% confidence interval, .85-.99). Presence of an ID specialist was also associated with lower use of broad-spectrum antibacterials (0.61; .54-.70) and higher narrow-spectrum ß-lactam use (1.43; 1.22-1.67). Total antibacterial exposure (inpatient plus postdischarge) was lower among patients at ID versus non-ID sites (0.92; .86-.99). CONCLUSIONS: Patients at hospitals with an ID specialist received antibiotics in a way more consistent with stewardship principles. The presence of an ID specialist may be important to effective antibiotic stewardship.

Expanding an Economic Evaluation of the Veterans Affairs (VA) Methicillin-resistant Staphylococcus aureus (MRSA) Prevention Initiative to Include Prevention of Infections From Other Pathogens.

BACKGROUND: In October 2007, Veterans Affairs (VA) launched a nationwide effort to reduce methicillin-resistant Staphylococcus aureus (MRSA) transmission called the National MRSA Prevention Initiative. Although the initiative focused on MRSA, recent evidence suggests that it also led to a significant decrease in hospital-onset (HO) gram-negative rod (GNR) bacteremia, vancomycin-resistant Enterococci (VRE), and Clostridioides difficile infections. The objective of this analysis was to evaluate the cost-effectiveness and the budget impact of the initiative taking into account MRSA, GNR, VRE, and C. difficile infections. METHODS: We developed an economic model using published data on the rate of MRSA hospital-acquired infections (HAIs) and HO-GNR bacteremia in the VA from October 2007 to September 2015, estimates of the attributable cost and mortality of these infections, and the costs associated with the intervention obtained through a microcosting approach. We explored several different assumptions for the rate of infections that would have occurred if the initiative had not been implemented. Effectiveness was measured in life-years (LYs) gained. RESULTS: We found that during fiscal years 2008-2015, the initiative resulted in an estimated 4761-9236 fewer MRSA HAIs, 1447-2159 fewer HO-GNR bacteremia, 3083-3602 fewer C. difficile infections, and 2075-5393 fewer VRE infections. The initiative itself was estimated to cost $561 million over this 8-year period, whereas the cost savings from prevented MRSA HAIs ranged from $165 to $315 million and from prevented HO-GNR bacteremia, CRE and C. difficile infections ranged from $174 to $200 million. The incremental cost-effectiveness of the initiative ranged from $12 146 to $38 673/LY when just including MRSA HAIs and from $1354 to $4369/LY when including the additional pathogens. The overall impact on the VA's budget ranged from $67 to$195 million. CONCLUSIONS: An MRSA surveillance and prevention strategy in VA may have prevented a substantial number of infections from MRSA and other organisms. The net increase in cost from implementing this strategy was quite small when considering infections from all types of organisms. Including spillover effects of organism-specific prevention efforts onto other organisms can provide a more comprehensive evaluation of the costs and benefits of these interventions.

Comparative Effectiveness of Switching to Daptomycin Versus Remaining on Vancomycin Among Patients With Methicillin-resistant Staphylococcus aureus (MRSA) Bloodstream Infections.

BACKGROUND: Patients with methicillin-resistant Staphylococcus aureus bloodstream infections (MRSA BSI) usually receive initial treatment with vancomycin but may be switched to daptomycin for definitive therapy, especially if treatment failure is suspected. Our objective was to evaluate the effectiveness of switching from vancomycin to daptomycin compared with remaining on vancomycin among patients with MRSA BSI. METHODS: Patients admitted to 124 Veterans Affairs Hospitals who experienced MRSA BSI and were treated with vancomycin during 2007-2014 were included. The association between switching to daptomycin and 30-day mortality was assessed using Cox regression models. Separate models were created for switching to daptomycin any time during the first hospitalization and for switching within 3 days of receiving vancomycin. RESULTS: In total, 7411 patients received vancomycin for MRSA BSI. Also, 606 (8.2%) patients switched from vancomycin to daptomycin during the first hospitalization, and 108 (1.5%) switched from vancomycin to daptomycin within 3 days of starting vancomycin. In the multivariable analysis, switching to daptomycin within 3 days was significantly associated with lower 30-day mortality (hazards ratio [HR] = 0.48; 95% confidence interval [CI]: .25, .92). However, switching to daptomycin at any time during the first hospitalization was not significantly associated with 30-day mortality (HR: 0.87; 95% CI: .69, 1.09). CONCLUSIONS: Switching to daptomycin within 3 days of initial receipt of vancomycin is associated with lower 30-day mortality among patients with MRSA BSI. This benefit was not seen when the switch occurred later. Future studies should prospectively assess the benefit of early switching from vancomycin to other anti-MRSA antibiotics.

A comprehensive assessment of carbapenem use across 90 Veterans Health Administration hospitals with defined stewardship strategies for carbapenems.

OBJECTIVES: Carbapenems are an important target for antimicrobial stewardship (AS) efforts. In this study, we sought to compare different hospital-based strategies for improving carbapenem use. METHODS: We analysed a cohort of all patients hospitalized at Veterans Health Administration (VHA) acute care hospitals during 2016 and a mandatory survey that characterized each hospital's carbapenem-specific AS strategy into one of three types: no strategy (NS), prospective audit and feedback (PAF) or restrictive policies (RP). Carbapenem use was compared using risk-adjusted generalized estimating equations that accounted for clustering within hospitals. Two infectious disease (ID) physicians independently performed manual chart reviews in 425 randomly selected cases. Auditors assessed carbapenem appropriateness with an assessment score on Day 4 of therapy. RESULTS: There were 429 062 admissions in 90 sites (24 NS, 8 PAF, 58 RP). Carbapenem use was lower at PAF than NS sites [rate ratio (RR) 0.6 (95% CI 0.4-0.9); P = 0.01] but similar between RP and NS sites. Carbapenem prescribing was considered appropriate/acceptable in 215 (50.6%) of the reviewed cases. Assessment scores were lower (i.e. better) at RP than NS sites (mean 2.3 versus 2.7; P < 0.01) but did not differ significantly between NS and PAF sites. ID consultations were more common at PAF/RP than NS sites (51% versus 29%; P < 0.01). ID consultations were associated with lower (i.e. better) assessment scores (mean 2.3 versus 2.6; P < 0.01). CONCLUSIONS: In this VHA cohort, PAF strategies were associated with lower carbapenem use and ID consultation and RP strategies were associated with more appropriate carbapenem prescribing. AS and ID consultations may work complementarily and hospitals could leverage both to optimize carbapenem use.

The feasibility of implementing antibiotic restrictions for fluoroquinolones and cephalosporins: a mixed-methods study across 15 Veterans Health Administration hospitals.

INTRODUCTION: The optimal method for implementing hospital-level restrictions for antibiotics that carry a high risk of Clostridioides difficile infection has not been identified. We aimed to explore barriers and facilitators to implementing restrictions for fluoroquinolones and third/fourth-generation cephalosporins. METHODS: This mixed-methods study across a purposeful sample of 15 acute-care, geographically dispersed Veterans Health Administration hospitals included electronic surveys and semi-structured interviews (September 2018 to May 2019). Surveys on stewardship strategies were administered at each hospital and summarized with descriptive statistics. Interviews were performed with 30 antibiotic stewardship programme (ASP) champions across all 15 sites and 19 additional stakeholders at a subset of 5 sites; transcripts were analysed using thematic content analysis. RESULTS: The most restricted agent was moxifloxacin, which was restricted at 12 (80%) sites. None of the 15 hospitals restricted ceftriaxone. Interviews identified differing opinions on the feasibility of restricting third/fourth-generation cephalosporins and fluoroquinolones. Some participants felt that restrictions could be implemented in a way that was not burdensome to clinicians and did not interfere with timely antibiotic administration. Others expressed concerns about restricting these agents, particularly through prior approval, given their frequent use, the difficulty of enforcing restrictions and potential unintended consequences of steering clinicians towards non-restricted antibiotics. A variety of stewardship strategies were perceived to be effective at reducing the use of these agents. CONCLUSIONS: Across 15 hospitals, there were differing opinions on the feasibility of implementing antibiotic restrictions for third/fourth-generation cephalosporins and fluoroquinolones. While the perceived barrier to implementing restrictions was frequently high, many hospitals were effectively using restrictions and reported few barriers to their use.

The Effectiveness of Contact Precautions on Methicillin-Resistant Staphylococcus aureus in Long-term Care Across the United States.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of health care-associated infections in long-term care facilities (LTCFs). The Centers for Disease Control and Prevention recommends contact precautions for the prevention of MRSA within acute care facilities, which are being used within the United States Department of Veterans Affairs (VA) for LTCFs in a modified fashion. The impact of contact precautions in long-term care is unknown. METHODS: To evaluate whether contact precautions decreased MRSA acquisition in LTCFs, compared to standard precautions, we performed a retrospective effectiveness study (pre-post, with concurrent controls) using data from the VA health-care system from 1 January 2011 until 31 December 2015, 2 years before and after a 2013 policy recommending a more aggressive form of contact precautions. RESULTS: Across 75 414 patient admissions from 74 long-term care facilities in the United States, the overall unadjusted rate of MRSA acquisition was 2.6/1000 patient days. Patients were no more likely to acquire MRSA if they were cared for using standard precautions versus contact precautions in a multivariable, discrete time survival analysis, controlling for patient demographics, risk factors, and year of admission (odds ratio, 0.97; 95% confidence interval, .85-1.12; P = .71). CONCLUSIONS: MRSA acquisition and infections were not impacted by the use of active surveillance and contact precautions in LTCFs in the VA.

Inpatient Fluoroquinolone Stewardship Improves the Quantity and Quality of Fluoroquinolone Prescribing at Hospital Discharge: A Retrospective Analysis Among 122 Veterans Health Administration Hospitals.

BACKGROUND: Despite increasing awareness of harms, fluoroquinolones are still frequently prescribed to inpatients and at hospital discharge. Our goal was to describe fluoroquinolone prescribing at hospital discharge across the Veterans Health Administration (VHA) and to contrast the volume and appropriateness of fluoroquinolone prescribing across 3 antimicrobial stewardship strategy types. METHODS: We analyzed a retrospective cohort of patients hospitalized at 122 VHA acute-care hospitals during 2014-2016. Data from a mandatory VHA survey were used to identify 9 hospitals that self-reported 1 of 3 strategies for optimizing fluoroquinolone prescribing: prospective audit and feedback (PAF), restrictive policies (RP), and no strategy. Manual chart reviews to assess fluoroquinolone appropriateness at hospital discharge (ie, postdischarge) were performed across the 9 hospitals (3 hospitals and 125 cases per strategy type). RESULTS: There were 1.7 million patient admissions. Overall, there were 1 727 478 fluoroquinolone days of therapy (DOTs), with 674 918 (39.1%) DOTs prescribed for inpatients and 1 052 560 (60.9%) DOTs prescribed postdischarge. Among the 9 reviewed hospitals, postdischarge fluoroquinolone exposure was lower at hospitals using RP, compared to no strategy (3.8% vs 9.3%, respectively; P = .012). Postdischarge fluoroquinolones were deemed inappropriate in 154 of 375 (41.1%) patients. Fluoroquinolones were more likely to be inappropriate at hospitals without a strategy (52.8%) versus those using either RP or PAF (35.2%; P = .001). CONCLUSIONS: In this retrospective cohort, the majority of fluoroquinolone DOTs occurred after hospital discharge. A large proportion of postdischarge fluoroquinolone prescriptions were inappropriate, especially in hospitals without a strategy to manage fluoroquinolone prescribing. Our findings suggest that stewardship efforts to minimize and improve fluoroquinolone prescribing should also focus on antimicrobial prescribing at hospital discharge.

Did the ban on serving raw beef liver in restaurants decrease Enterohemorrhagic Escherichia coli infection in Japan?: an interrupted time-series analysis.

BACKGROUND: Enterohemorrhagic Escherichia coli (EHEC) is an important pathogen that causes diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome (HUS). After an EHEC outbreak involving uncooked beef, serving raw beef liver dishes at restaurants was completely banned starting on July 1, 2012 in Japan. However, its long-term associations with the incidence rates of EHEC infections have never been assessed by formal interrupted time-series analysis (ITSA). METHODS: A retrospective cohort study to assess the impact of banning raw beef liver provision at restaurants was conducted. The weekly incidence of asymptomatic and symptomatic EHEC infections, the incidence of HUS, and deaths were extracted from the national reportable diseases database from January 2008 to December 2017. ITSA was conducted to evaluate the impact of banning raw beef liver from July 2012. To account for a potential simultaneous external effect, the additional regulation on raw beef red meat handling (implemented in May 2011) and the seasonality were also incorporated into the model. RESULTS: There were 32,179 asymptomatic and 21,250 symptomatic EHEC infections (including 717 HUS cases and 26 deaths) reported during the study period. During the pre-intervention period (before week 27, 2012), there were 0.45 asymptomatic EHEC infections per million-persons per week. The mean post-intervention asymptomatic EHEC infections were 0.51 per million-persons per week. ITSA revealed no baseline trend or change in the intercept and trend (0.002 infections per million-persons per week, 95% Confidence interval - 0.03-0.04, p = 0.93, 1.22, CI -1.96-4.39, p = 0.45, and - 0.006, CI -0.003-0.02, p = 0.68, respectively). For symptomatic EHEC infections, there were 0.30 cases per million per week during the pre-intervention period, and it became 0.33 cases per million per week after the intervention. Time series modeling again did not show a significant baseline trend or changes in the intercept and trend (0.0005, CI -0.02-0.02, p = 0.96, 0.69, CI -1.75-3.12, p = 0.58, and - 0.003, CI -0.02-0.01, p = 0.76, respectively). CONCLUSION: We did not find a statistically significant reduction in the overall incidence rates of both asymptomatic and symptomatic EHEC infections in Japan after implementing measures, including a ban on serving raw beef liver dishes in the restaurant industry.

Comparative Effectiveness of Cefazolin Versus Nafcillin or Oxacillin for Treatment of Methicillin-Susceptible Staphylococcus aureus Infections Complicated by Bacteremia: A Nationwide Cohort Study.

Background: To treat patients with methicillin-susceptible Staphylococcus aureus (MSSA) infections, ß-lactams are recommended for definitive therapy; however, the comparative effectiveness of individual ß-lactams is unknown. This study compared definitive therapy with cefazolin vs nafcillin or oxacillin among patients with MSSA infections complicated by bacteremia. Methods: This retrospective study included patients admitted to 119 Veterans Affairs hospitals from 2003 to 2010. Patients were included if they had a blood culture positive for MSSA and received definitive therapy with cefazolin, nafcillin, or oxacillin. Cox proportional hazards regression and ordinal logistic regression were used to identify associations between antibiotic therapy and mortality or recurrence. A recurrent infection was defined as a MSSA blood culture between 45 and 365 days after the first MSSA blood culture. Results: Of 3167 patients, 1163 (37%) patients received definitive therapy with cefazolin. Patients who received cefazolin had a 37% reduction in 30-day mortality (hazard ratio [HR], 0.63; 95% confidence interval [CI], .51-.78) and a 23% reduction in 90-day mortality (HR, 0.77; 95% CI, .66-.90) compared with patients receiving nafcillin or oxacillin, after controlling for other factors. The odds of recurrence (odds ratio, 1.13; 95% CI, .94-1.36) were similar among patients who received cefazolin compared with patients who received nafcillin or oxacillin, after controlling for other factors. Conclusions: In this large, multicenter study, patients who received cefazolin had a lower risk of mortality and similar odds of recurrent infections compared with nafcillin or oxacillin for MSSA infections complicated by bacteremia. Physicians might consider definitive therapy with cefazolin for these infections.

Antimicrobial Nonsusceptibility of Gram-Negative Bloodstream Isolates, Veterans Health Administration System, United States, 2003-20131.

Bacteremia caused by gram-negative bacteria is associated with serious illness and death, and emergence of antimicrobial drug resistance in these bacteria is a major concern. Using national microbiology and patient data for 2003-2013 from the US Veterans Health Administration, we characterized nonsusceptibility trends of community-acquired, community-onset; healthcare-associated, community-onset; and hospital-onset bacteremia for selected gram-negative bacteria (Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa, and Acinetobacter spp.). For 47,746 episodes of bacteremia, the incidence rate was 6.37 episodes/10,000 person-years for community-onset bacteremia and 4.53 episodes/10,000 patient-days for hospital-onset bacteremia. For Klebsiella spp., P. aeruginosa, and Acinetobacter spp., we observed a decreasing proportion of nonsusceptibility across nearly all antimicrobial drug classes for patients with healthcare exposure; trends for community-acquired, community-onset isolates were stable or increasing. The role of infection control and antimicrobial stewardship efforts in inpatient settings in the decrease in drug resistance rates for hospital-onset isolates needs to be determined.