A community-university run conference as a catalyst for addressing health disparities in an urban community.

The African American population of Buffalo, New York experiences striking race-based health disparities due to adverse social determinants of health. A team of community leaders and university faculty determined that a community dialogue was needed to focus research and advocacy on the root causes of these disparities. In response, we organized the annual Igniting Hope conference series that has become the premier conference on health disparities in the region. The series, now supported by an R13 conference grant from NCATS, has been held four times (2018-2021) and has attracted community members, community leaders, university faculty, and trainees. The agenda includes talks by national leaders and breakout/working groups that led to a new state law that has reduced disproportionate traffic-ticketing and drivers' license suspensions in Black neighborhoods; mitigation of the disproportionate COVID-19 fatalities in Black communities; and the launching of a university-supported institute. We describe the key elements of success for a conference series designed by a community-university partnership to catalyze initiatives that are having an impact on social determinants of health in Buffalo.

Outcomes of multiple sclerosis patients admitted with COVID-19 in a large veteran cohort.

BACKGROUND: Given concerns over immune function, the decision whether to continue disease modifying therapy (DMT) in multiple sclerosis (MS) patients during the COVID-19 pandemic has been challenging, complicated by the risk of MS disease progression in the absence of treatment. METHODS: This retrospective analysis of patients treated for COVID-19 infection at veteran affairs healthcare systems across the United States, investigated 30-day all-cause mortality after first positive COVID-19 in patients with and without MS. We examined mortality risk impact of disease modifying therapy for MS, accounting for other relevant factors known to be associated with COVID-19 mortality. Patients were propensity score matched in a 1:20 fashion based on MS diagnosis. RESULTS: 49,737 COVID-19 inpatient cases were identified, of which 258 were diagnosed with MS. In the propensity score matched cohort, MS patients taking DMT (excluding those receiving anti-CD20 antibodies) had a lower odds of 30 day mortality (OR: 0.18 [95%CI: 0.00988-0.94] p=0.041). Similarly, in the unmatched cohort, patients on DMT had a lower risk of death (OR: 0.16 [95%CI: 0.01-0.82] p=0.023). There was no statistically significant difference in mortality between those with and without MS. In the propensity matched cohort, age over 65, heart failure, chronic kidney disease (CKD), and diabetes increased the risk of mortality while vaccination reduced the risk of mortality. CONCLUSION: Veteran patients with MS hospitalized for COVID-19 were less likely to die when taking DMTs (excluding those receiving anti-CD20 antibodies), accounting for other relevant factors. Results suggest that, in relation to the COVID-19 pandemic, not only is it safe to continue most DMTs in people with MS, but it may be beneficial given the decreased risk of COVID-19 mortality and decreased risk of MS disease progression.

Admissions and Mortality Related to Urinary Tract Infections in Male Veterans with Dementia.

Objective To examine mortality and hospital readmission rates in male veterans with dementia diagnosed with urinary tract infection (UTI) compared with patients without dementia. Design Retrospective cohort study. Setting Veterans Healthcare Systems (VA). Participants Male inpatients with a diagnosis of UTI who were treated at any VA Healthcare Center from January 1, 2009, to December 31, 2018. Interventions None. Main Outcome Measures Mortality and hospital readmission for patients with and without dementia at 30, 60, and 90 days from UTI diagnosis. Results 262,515 veterans admitted with UTI were analyzed, and 58,940 (22.5%) had dementia. The mean age for veterans with dementia was 80.0 +/- 9.7 years. Veterans with dementia experienced less mortality than patients without dementia at 30 days (8.3% vs 8.5%; P < 0.001), but more mortality at 60-day (4.9% vs 4.7%; P < 0.001) and 90-day (3.6% vs 3.3%; P < 0.001) intervals. Death was 20% less likely at 30 days in patients with dementia. Veterans with dementia were readmitted more than those without dementia at 30-day (18.4% vs 16.0%), 60-day (4.5% vs 2.8%), and 90-day (3.4% vs 2.5%) intervals; P < 0.0001. Conclusion Though patients with dementia are at an increased risk for death long-term, risk of death is less than those without dementia shortly following UTI diagnosis. This highlights the possibility that veterans with dementia may be hospitalized and diagnosed with UTIs when in actuality they have asymptomatic bacteriuria. Patients with dementia and UTI therefore represent an important group of geriatric patients that could benefit from the oversight of a senior care pharmacist to help prevent unnecessary treatment of asymptomatic bacteriuria.

Trends in beta-hemolytic Streptococcus infections within Veterans' Affairs medical centers from 2009 to 2018.

OBJECTIVE: The purpose of this study was to describe the recent trends of invasive and noninvasive ß-hemolytic Streptococcus cultures in the Veterans' Affairs (VA) cohort from 2009 to 2018. DESIGN: Retrospective cohort study from January 1, 2009, to January 1, 2019. SETTING: Veterans' Affairs medical centers. PATIENTS OR PARTICIPANTS: All patients aged 18 years and older with cultures positive for ß-hemolytic Streptococcus at a VA facility were included in the study. INTERVENTION(S): Data were retrieved from the VA Corporate Data Warehouse using structure query language through the SQL Server Management Studio software. RESULTS: Between 2009 and 2018, there were 40,625 patients with cultures with ß-hemolytic Streptococcus. The median age was 64 years (interquartile range [IQR], 55-71) and the median Charlson comorbidity index was 4 (IQR, 2-7). Distributions for each type of ß-hemolytic Streptococcus based on site of culture are provided. The 30-day all-cause mortality rate from all invasive ß-hemolytic Streptococcus cases was 2.3%, and the 90-day all-cause mortality rate was 4.4%. The 30- and 90-day all-cause mortality rates for Streptococcus cases were higher for group A (3.9% and 6.1% respectively) and for groups C and G combined (3.2% and 6.1%, respectively) than for group B (2.0% and 4.0%, respectively). CONCLUSIONS: Trends of cultures for invasive and noninvasive ß-hemolytic Streptococcus suggest an association with disease and mortality. The burden associated with ß-hemolytic Streptococcus infections should not be underestimated.

Societal factors contributing to infections caused by Chlamydia trachomatis and Neisseria gonorrhoeae in a veteran population.

BACKGROUND: Veterans have a higher incidence of sexually transmitted infections (STIs) compared to the general population. The objective of this study is to evaluate the association of societal factors on the risk of chlamydia or gonorrhea. METHODS: This retrospective cohort study evaluated data from Veteran Health Administration. Patients tested for chlamydia or gonorrhea between January 2009 and January 2019 were included. Descriptive statistics and regression were used to evaluate societal factors. RESULTS: A total of 1,232,173 tests for chlamydia or gonorrhea were performed. There were 51,987 (4.2%) positive cases with 74.18% for chlamydia and 24.96% for gonorrhea. In 13.6% of veterans with reported military sexual trauma, there was no difference in risk of positivity (p = 0.39). Veterans with a history of combat had lower odds of testing positive (OR, 0.94; 95% CI, 0.91-0.97). Tests in veterans who were married had a 24% less chance of positivity (OR, 0.76; 95% CI, 0.74-0.79) compared to tests in divorced veterans. Positive number of cases increased each year. CONCLUSION: Sexually transmitted infections are a growing concern. Gender, age, ethnicity, marital status, and race are societal identifiers which influence likelihood of STI acquisition.

Sputum susceptibilities in a nationwide veteran cohort.

BACKGROUND: Respiratory infections are one of the most common causes of morbidity and mortality. This study examined antimicrobial susceptibility of common respiratory isolates from veterans. METHODS: Sputum culture data from the Veteran Health Administration were obtained retrospectively between January 2009 and 2019. Cumulative antibiograms were constructed for bacterial isolate susceptibility. RESULTS: Sputum and bronchial cultures from approximately 10,345 veterans were included each year. Haemophilus influenzae has maintained high levels of susceptibility to third generation cephalosporins from 2009 (99.7%) to 2018 (97.2%). Third generation cephalosporin susceptibilities amongst Klebsiella pneumoniae have trended upward from 2009 to 2018 as well (79.1% vs 86.4%). In Pseudomonas aeruginosa isolates, there has been an increase in susceptibility rates to cefepime from 2009 to 2018 (79.6%, to 86.6%), gentamicin (81.5% to 89.1%), and piperacillin/tazobactam (86.5% to 90%). Fluoroquinolone susceptibilities amongst Escherichia coli have remained low but stable between 2009 and 2018. Third generation cephalosporin susceptibilities for S. pneumoniae improved slightly from 92.2% to 95% between 2009 and 2018 while susceptibility to azithromycin trended down slightly from 56.8% in 2009 to 51.7% in 2018 for S. pneumoniae. DISCUSSION: The antibiogram of sputum isolates from the VA Healthcare System were examined to determine changes in patterns of resistance over a decade of use. CONCLUSIONS: This large-scale study investigated nationwide sputum culture susceptibility trends. Avoidance of macrolides for empiric treatment of community acquired pneumonia and avoidance of fluoroquinolones for empiric treatment of hospital acquired or ventilator associated pneumonia may be warranted based on susceptibility trends.

Antimicrobial susceptibility trends for urinary isolates in the veteran population.

BACKGROUND: Guidance on empiric treatment for urinary tract infections (UTIs) is lacking for the male population which comprises much of the Veteran population in the United States. This study evaluated susceptibility trends in antimicrobials used for treatment of UTIs in the inpatient and outpatient Veteran population nationwide. METHODS: Urine culture data was retrospectively obtained from Corporate Data Warehouse. All urine cultures from Veteran Health Administration patients 18 years of age or older who were treated at any VA health care center in the years 2009 and 2018 were eligible. Antibiograms were constructed for bacterial isolate susceptibility. RESULTS: In 2009 and 2018 isolates from 54,788 and 58,983 Veterans were analyzed, respectively. Escherichia coli was the most common bacteria isolated. For ceftriaxone, E coli susceptibilities were relatively high but trended downward from 2009 to 2018. Common urinary pathogen susceptibilities remained low for fluoroquinolones and trimethoprim-sulfamethoxazole. DISCUSSION: Empiric therapy for Veterans with UTIs should be based on local susceptibility patterns as previously recommended first-line agents have fallen out of favor due to increasing resistance rates. CONCLUSIONS: Both inpatient and outpatient stewardship is needed to ensure appropriate treatment, as viable treatment options for UTIs are becoming increasingly limited.

Utility of Methicillin-Resistant Staphylococcus aureus Nares Screening for Patients with a Diabetic Foot Infection.

Treatment of suspected methicillin-resistant Staphylococcus aureus (MRSA) is a cornerstone of severe diabetic foot infections; however, antibiotics can be associated with toxicity. The objective of this study was to determine the negative predictive value (NPV) of MRSA nares screening in the determination of subsequent MRSA in patients with a diabetic foot infection. This was a retrospective cohort study across Veterans Affairs (VA) medical centers from 1 January 2007 to 1 January 2018. Data from patients with an International Classification of Diseases (ICD) code for a diabetic foot infection with MRSA nares screening, and subsequent cultures were evaluated for the presence of MRSA. NPVs were calculated for the entire cohort, as well as for a subgroup representing deep cultures. Additionally, the distribution of all pathogens isolated from diabetic foot infections was determined. A total of 8,163 episodes were included in the analysis for NPV. The NPV of MRSA nares screening for MRSA diabetic foot infection was 89.6%. For the deep cultures, the NPV was 89.2%. The NPV for cultures originating from the foot was 89.7%, and the NPV for those originating from the toe was 89.4%. There were 17,822 pathogens isolated from the diabetic foot cultures. MRSA was isolated in 7.5% of cultures, and methicillin-susceptible S. aureus was isolated in 24.8%. Enterococcus was identified in 14.7% of cultures, Proteus in 7.3%, and Pseudomonas in 6.8% of cultures. Given the high NPVs, the use of MRSA nares screening may be appropriate as a stewardship tool for deescalation and avoidance of empirical anti-MRSA therapy in patients who are not nasal carries of MRSA.

Determining the Utility of Methicillin-Resistant Staphylococcus aureus Nares Screening in Antimicrobial Stewardship.

BACKGROUND: Treatment of suspected methicillin-resistant Staphylococcus aureus (MRSA) is a cornerstone of many antibiotic regimens; however, there is associated toxicity. The Department of Veterans Affairs (VA) hospitals screen each patient for MRSA nares colonization on admission and transfer. The objective was to determine the negative predictive value (NPV) of MRSA screening in the determination of subsequent positive clinical culture for MRSA. High NPVs with MRSA nares screening may be used as a stewardship tool. METHODS: This was a retrospective cohort study across VA medical centers nationwide from 1 January 2007 to 1 January 2018. Data from patients with MRSA nares screening were obtained from the VA Corporate Data Warehouse. Subsequent clinical cultures within 7 days of the nares swab were evaluated for the presence of MRSA. Sensitivity, specificity, positive predictive values, and NPVs were calculated for the entire cohort as well as subgroups for specific culture sites. RESULTS: This cohort yielded 561 325 clinical cultures from a variety of anatomical sites. The sensitivity and specificity for positive MRSA clinical culture were 67.4% and 81.2%, respectively. The NPV of MRSA nares screening for ruling out MRSA infection was 96.5%. The NPV for bloodstream infections was 96.5%, for intraabdominal cultures it was 98.6%, for respiratory cultures it was 96.1%, for wound cultures it was 93.1%, and for cultures from the urinary system it was 99.2%. CONCLUSION: Given the high NPVs, MRSA nares screening may be a powerful stewardship tool for deescalation and avoidance of empirical anti-MRSA therapy.

Temporal trends of inpatient C. difficile infections within the Veterans Health Administration hospitals: An analysis of the effect of molecular testing, time to testing, and mandatory reporting.

BACKGROUND: Clostridium difficile infection (CDI) is a reportable hospital metric associated with significant healthcare expenditures. The epidemiology of CDI is pivotal to the implementation of preventative measures. OBJECTIVE: To portray temporal CDI trends in Veterans Health Administration (VA) hospitals. DESIGN: A retrospective analysis of veterans who had stool testing for C. difficile. SETTING: VA acute-care hospitals within the continental United States. METHODS: Data were mined from the VA's Corporate Data Warehouse. CDI is reported per 10,000 patient days. RESULTS: From 2006 to 2016, 472,346 patients had C. difficile testing. Overall, decreases in incidence of total CDI (16.81 to 13.66) and hospital-onset healthcare facility-associated (HO-HCFA) CDI (10.87 to 6.41) were observed. Temporal increases in the incidence of total and HO-HCFA CDI were associated with the increased use of molecular testing (P < .0001). Decreased use of fluoroquinolones (P < .0001), clindamycin (P = .0006), and third-generation cephalosporins (P = .0002) correlated with decreased rates of CDI, but VA mandatory reporting did not influence CDI rates (P = .24). The overall crude 30-day mortality of patients with CDI decreased from 2.17 deaths per 10,000 patient days in 2006 to 1.41 in 2016. The frequency of International Classification of Disease, Ninth/Tenth Revision (ICD-9/10) discharge diagnosis for CDI was 73.3%. CONCLUSION: Molecular testing was associated with increased incidence of CDI. Controlling CDI is likely multifactorial. Although the VA initiative to report cases of hospital-acquired CDI was not significant in our model, the advent of stewardship programs throughout the VA and reductions in the use of third-generation cephalosporins, fluoroquinolones, and clindamycin were significantly associated with reduced rates of CDI.

A combination of ceftaroline and daptomycin has synergistic and bactericidal activity in vitro against daptomycin nonsusceptible methicillin-resistant Staphylococcus aureus (MRSA).

There is an urgent need to optimize therapeutic options in patients with methicillin-resistant Staphylococcus aureus (MRSA) bacteremia who have failed conventional therapy. Two clinical isolates were obtained from a 68-year-old male with persistent MRSA bacteremia before and after the development of daptomycin nonsusceptibility. The pharmacodynamic activity of monotherapies and combinations of ceftaroline, daptomycin, cefoxitin, nafcillin and vancomycin were evaluated in time-kill experiments versus 108 CFU/mL of the pre- and post-daptomycin nonsusceptible MRSA isolates. Cefoxitin, nafcillin and vancomycin alone or in combination with ceftaroline failed to generate prolonged bactericidal activity against the post-daptomycin nonsusceptible isolate whereas a ceftaroline-daptomycin combination resulted in 6, 24 and 48 h log10(CFU/mL) reductions of 3.90, 4.40 and 6.32. Population analysis profiles revealed a daptomycin heteroresistant subpopulation of the pre-daptomycin nonsusceptible MRSA isolate that expanded by >10,000× on daptomycin agar containing 2-16 mg/L in the post-daptomycin nonsusceptible isolate. Daptomycin and ceftaroline combinations may be promising against persistent MRSA bacteremia.

An Outbreak of Severe Group A Streptococcus Infections Associated with Podiatric Application of a Biologic Dermal Substitute.

OBJECTIVE: To describe an outbreak of severe Group A Streptococcus (GAS) infections that appeared to be associated with use of a biologic dermal substitute on foot wounds DESIGN: Retrospective cohort study of cases and similar uninfected patients SETTING/PATIENTS: Patients attending the podiatry clinic at a Veterans Affairs Medical Center between July 2011 and November 2011 INTERVENTIONS: Microbiology laboratory data were reviewed for the calendar year, a case definition was established and use of the biologic dermal substitute was discontinued. Staff were cultured to identify potentially colonized employees. A case-cohort study was designed to investigate risk factors for disease. Emm typing and pulsed field gel electrophoresis (PFGE) were performed to identify strain similarity. RESULTS: In 10 months, 14 cases were identified, and 4 of these patients died. All strains were emm type 28 and were identical according to PFGE. Discontinuation of biologic dermal substitute use halted the outbreak. A prior stroke was more common in the case cohort vs uninfected patient cohorts. The number of patients attending the clinic on 13 probable transmission days was significantly higher than on nontransmission days. We identified 2 patients who were present in the clinic on all but 1 probable transmission day. Surveillance cultures of podiatry clinic staff and cultures of the same lot of retained graft material were negative. CONCLUSIONS: A carrier was not identified, and we believe the outbreak was associated with inter-patient transmission likely due to lapses in infection control techniques. No additional cases have been identified in >3 years following the resumption of dermal substitute use in May 2012.

Activity of AFN-1252, a novel FabI inhibitor, against Staphylococcus aureus in an in vitro pharmacodynamic model simulating human pharmacokinetics.

AFN-1252, a potent enoyl-ACP reductase (FabI) inhibitor, is under development for the treatment of Staphylococcus aureus infections. The activity of AFN-1252 against two isolates of S. aureus, MSSA 26213 and MRSA S186, was studied in an in vitro pharmacodynamic model simulating AFN-1252 pharmacokinetics in man. Reductions in bacterial viable count over the first 6 hours were generally 1-2 logs and maximal reductions in viable count were generally achieved at fAUC/MIC ratios of 100-200. Maximum reductions in viable count against MSSA 29213 and MRSA S186 were approximately 4 logs, achieved by 450 mg q12h (fAUC/MIC = 1875) dosing at 28 hours. Staphylococcal resistance to AFN-1252 did not develop throughout the 48-hour experiments. As multidrug resistance continues to increase, these studies support the continued investigation of AFN-1252 as a targeted therapeutic for staphylococcal infections.

A clonal group of nontypeable Haemophilus influenzae with two IgA proteases is adapted to infection in chronic obstructive pulmonary disease.

Strains of nontypeable Haemophilus influenzae show enormous genetic heterogeneity and display differential virulence potential in different clinical settings. The igaB gene, which encodes a newly identified IgA protease, is more likely to be present in the genome of COPD strains of H. influenzae than in otitis media strains. Analysis of igaB and surrounding sequences in the present study showed that H. influenzae likely acquired igaB from Neisseria meningitidis and that the acquisition was accompanied by a ~20 kb genomic inversion that is present only in strains that have igaB. As part of a long running prospective study of COPD, molecular typing of H. influenzae strains identified a clonally related group of strains, a surprising observation given the genetic heterogeneity that characterizes strains of nontypeable H. influenzae. Analysis of strains by 5 independent methods (polyacrylamide gel electrophoresis, multilocus sequence typing, igaB gene sequences, P2 gene sequences, pulsed field gel electrophoresis) established the clonal relationship among the strains. Analysis of 134 independent strains collected prospectively from a cohort of adults with COPD demonstrated that ~10% belonged to the clonal group. We conclude that a clonally related group of strains of nontypeable H. influenzae that has two IgA1 protease genes (iga and igaB) is adapted for colonization and infection in COPD. This observation has important implications in understanding population dynamics of H. influenzae in human infection and in understanding virulence mechanisms specifically in the setting of COPD.

Characterization of heterogeneous vancomycin-intermediate resistance, MIC and accessory gene regulator (agr) dysfunction among clinical bloodstream isolates of staphyloccocus aureus.

BACKGROUND: The development of hVISA has been associated with vancomycin clinical failures and is commonly misidentified in clinical microbiology laboratories. Therefore, the objectives of this present study was to improve the reliability of methodologies and criteria for identifying hVISA, evaluate the prevalence of hVISA among clinical bloodstream isolates of S. aureus and determine if there exists a relationship between accessory gene regulator (agr) dysfunction and the hVISA phenotype. METHODS: The presence of hVISA in 220 clinical S. aureus isolates (121 MSSA, 99 MRSA) from bloodstream infections was examined by CLSI broth microdilution, Macro & Standard Etest. Isolates which were classified as hVISA by Macro Etest, were additionally evaluated using a modified PAP-AUC method using a modified starting inoculum of 10(10) CFU/mL, and growth on brain heart infusion agar with 4 mg/L vancomycin (BHIV4) at 10(8) and 10(10) CFU/mL, and agr function was assessed by delta-hemolysin production. RESULTS: Broth microdilution MIC(50/90) of S.aureus and hVISA was 1.0/2.0 and 1.5/2.0 mg/L (p= 0.02), respectively. Macro Etest identified 12 (5.5%) hVISA isolates; higher among MRSA (9.1%) versus MSSA (2.5%) (p = 0.03). The mean modified PAP-AUC ratios (> 0.8) of 7 MRSA strains and 3 MSSA strains were significantly different (p = 0.001). 58% of hVISA strains were found to be agr dysfunctional when 21% of MRSA strains were agr dysfunctional. hVISA was detected among S. aureus bloodstream isolates, which were classified as susceptible among clinical microbiology laboratories. CONCLUSIONS: Evaluating the correlation between Etest MICs and modified PAP-AUC ratio values will add further improvement of discriminating hVISA, and agr dysfunction may be predictive of strains which display a greater predilection to display the hVISA phenotype.

USA300 methicillin-resistant Staphylococcus aureus bacteremia and the risk of severe sepsis: is USA300 methicillin-resistant Staphylococcus aureus associated with more severe infections?

USA300 methicillin-resistant Staphylococcus aureus (MRSA) is increasing as a cause of severe community-associated bacteremic infections. We assessed severe sepsis in response to infection in patients with USA300 MRSA compared to non-USA300 MRSA bacteremia. A cohort study was conducted from 1997 to 2008 comparing sepsis in response to infection in 271 patients with MRSA bacteremia from 4 VA hospitals. Sixty-seven (25%) patients with MRSA bacteremia were USA300 MRSA; 204 (75%) were non-USA300 MRSA. The proportion of MRSA bacteremia caused by USA300 MRSA increased over time (χ² P < 0.0001). Adjusting for age and nosocomial infection, patients with USA300 MRSA bacteremia were more likely to have severe sepsis or septic shock in response to infection than patients with non-USA300 MRSA bacteremia (adjusted relative risk = 1.82; 95% confidence interval, 1.16-2.87; P = 0.01). This suggests that patients with USA300 MRSA are more likely to develop severe sepsis in response to their infection, which could be due to host or bacterial differences.

Genomic comparisons of USA300 Staphylococcus aureus colonizating the nose and rectum of children with skin abscesses.

USA300 Staphylococcus aureus is responsible for the current outbreak of skin abscesses in the United States. Unlike other USA types, USA300 colonizes the rectum at rates higher than the nose. The reason for the difference in colonization site preference may be related to specific adherence or attachment factors contained in the genome of these strains. Additional knowledge in this field may help design novel prophylactic and therapeutic strategies to combat staphylococcal infections. Strains of USA300 MSSA and MRSA colonizing the nose and/or rectum from children with staphylococcal skin abscesses were compared by whole genome array technology to identify bacterial genetic determinants associated with site-specific colonization. Strains isolated from different colonization sites were indistinguishable by genomic content. Site-specific colonization traits were not detected in the colonizing bacteria by this array. Either host characteristics associated with staphylococcal carriage or under represented bacterial genomic constructions need to be examined to determine the etiology of this site-specific colonization.

Illicit drug use and risk for USA300 methicillin-resistant Staphylococcus aureus infections with bacteremia.

To assess the association of illicit drug use and USA300 methicillin-resistant Staphylococcus aureus (MRSA) bacteremia, a multicenter study was conducted at 4 Veterans Affairs medical centers during 2004-2008. The study showed that users of illicit drugs were more likely to have USA300 MRSA bacteremia (in contrast to bacteremia caused by other S. aureus strains) than were patients who did not use illicit drugs (adjusted relative risk 3.0; 95% confidence interval 1.9-4.4). The association of illicit drug use with USA300 MRSA bacteremia decreased over time (p = 0.23 for trend). Notably, the proportion of patients with USA300 MRSA bacteremia who did not use illicit drugs increased over time. This finding suggests that this strain has spread from users of illicit drugs to other populations.