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Background Staphylococcus aureus bacteremia (SAB) disproportionately affects Black patients. The reasons for this disparity are unclear. Methods We evaluated a prospectively ascertained cohort of patients with SAB from 1995 to 2020. Clinical characteristics, bacterial genotypes, and outcome were compared among Black and White patients with SAB. Multivariable logistic regression models were used to determine factors independently associated with the outcomes. Results Among 3068 patients with SAB, 1107 (36%) were Black. Black patients were younger (median, 56 years vs 63 years; P < .001) and had higher rates of diabetes (47.5% vs 34.5%, P < .001), hemodialysis dependence (40.0% vs 7.3%, P < .001), and human immunodeficiency virus (6.4% vs 0.6%, P < .001). Black patients had higher rates of methicillin-resistant S. aureus (49.3% vs 44.9%, P = .020), including the USA300 hypervirulent clone (11.5% vs 8.4%, P = .007). White patients had higher rates of corticosteroid use (22.4% vs 15.8%, P < .0001) and surgery in the preceding 30 days (28.1% vs 18.7%, P < .001). Although the median Acute Physiology Score (APS) at the time of initial SAB diagnosis was significantly higher in Black patients (median APS, 9; interquartile range [IQR], 5–14 vs median APS, 7; IQR, 4–12; P < .001), race was not associated with 90-day mortality (risk ratio, 1.02; 95% confidence interval, .93–1.12), and rates of metastatic infection were lower among Black patients (37.2% vs 41.3% White, P = .029). Conclusions Despite differences in Black patients' higher APS on presentation and more risk factors, including a 5 times higher risk of hemodialysis dependence, 90-day mortality among Black and White patients with SAB was similar.

Background Broad-spectrum antibiotic use is a known risk factor for candidemia, but the duration and type of antibiotic exposure associated with greatest risk are not well characterized. Measurements of antibiotic days may be useful to assess cumulative burden of selective pressure on the microbiome and risk for candidemia. Methods This retrospective cohort study aimed to quantify the effect of antibiotic exposure on risk for candidemia. The primary outcome was hazard for developing candidemia across an array of antibiotic agents, classes and spectra. We measured antibiotic days of therapy (DOT) for adults admitted to Duke University hospitals 1/1/2016–12/31/2021. We excluded patients with community-onset candidemia, defined as growth of Candida spp. in blood culture collected ≤ 48 hours of admission, because antibiotic exposure prior to arrival was not reliably accessible. Time-to-event analyses were performed using the Nelson-Aalen estimator for modeling cumulative hazard functions to compare the proportion of candidemia observed based on exposure to each antibiotic. Logrank tests were used to evaluate for differences between hazard functions with a pre-specified alpha level of 0.05, and exponential cumulative proportional hazards models were implemented to generalize hazard functions. Results During 164,185 encounters in 105,330 unique patients, we identified candidemia in 237 patients. Prior to developing candidemia, cases received a total of 9,604 antibacterial DOT distributed across 46 unique antibiotic agents (Fig. 1) Carbapenems were associated with increased hazard for candidemia compared to beta-lactams (p< 0.005) (Figs. 2–3). There were 57 encounters for candidemia where meropenem was administered with a median of 10 DOT prior to onset of candidemia. Days of Antibiotic Therapy by Agent and Outcome. Conclusion This work represents a novel approach to quantifying antibiotic exposure as a risk factor for candidemia. In an unadjusted model, we identified carbapenems as a high-risk class; additional analysis with adjusted regression models will help contextualize exposure risk with respect to comorbidity and illness severity. This work may serve as a reference for antibiotic stewards as they promote appropriate antibiotic use, including reducing overuse of broad-spectrum antibiotics. Disclosures Rebekah W. Moehring, MD, MPH, FIDSA, FSHEA, UpToDate, Inc.: Author Royalties Barbara D. Alexander, MD, Astellas: Advisor/Consultant|HealthtrackRx: Advisor/Consultant|HealthtrackRx: Grant/Research Support|Scynexis: Grant/Research Support|UpToDate: Advisor/Consultant Melissa D. Johnson, PharmD, Biomeme: Licensed Transcriptional Signature for Candidemia|Charles River Laboratories: Grant/Research Support|Entasis Therapeutics: Advisor/Consultant|Merck & Co. Inc: Advisor/Consultant|Merck & Co. Inc: Grant/Research Support|Pfizer, Inc.: Advisor/Consultant|Scynexis Inc.: Grant/Research Support|Theratechnologies: Advisor/Consultant.

Background The causes and clinical characteristics of recurrent gram-negative bacterial bloodstream infections (GNB-BSI) are poorly understood. Methods We used a cohort of patients with GNB-BSI to identify clinical characteristics, microbiology, and risk factors associated with recurrent GNB-BSI. Bacterial genotyping (pulsed-field gel electrophoresis [PFGE] and whole-genome sequencing [WGS]) was used to determine whether episodes were due to relapse or reinfection. Multivariable logistic regression was used to identify risk factors for recurrence. Results Of the 1423 patients with GNB-BSI in this study, 60 (4%) had recurrent GNB-BSI. Non-White race (odds ratio [OR], 2.35; 95% confidence interval [CI], 1.38–4.01; P = .002), admission to a surgical service (OR, 2.18; 95% CI, 1.26–3.75; P = .005), and indwelling cardiac device (OR, 2.73; 95% CI, 1.21–5.58; P = .009) were associated with increased risk for recurrent GNB-BSI. Among the 48 patients with recurrent GNB-BSI whose paired bloodstream isolates underwent genotyping, 63% were due to relapse (30 of 48) and 38% were due to reinfection (18 of 48) based on WGS. Compared with WGS, PFGE correctly differentiated relapse and reinfection in 98% (47 of 48) of cases. Median time to relapse and reinfection was similar (113 days; interquartile range [IQR], 35–222 vs 174 days; IQR, 69–599; P = .13). Presence of a cardiac device was associated with relapse (relapse: 7 of 27, 26%; nonrelapse: 65 of 988, 7%; P = .002). Conclusions In this study, recurrent GNB-BSI was most commonly due to relapse. PFGE accurately differentiated relapse from reinfection when compared with WGS. Cardiac device was a risk factor for relapse.

Delayed identification and isolation of patients with Clostridiodies difficile infection (CDI) may contribute to in-hospital transmission and delay appropriate therapy. To assess potential points for intervention, we conducted a retrospective cohort study to determine differences in time-to-testing and time-to-isolation among community-onset (CO), community-onset healthcare facility-associated (CO-HCFA), and hospital-onset (HO) CDI.We compared clinical and demographic data of all CO, CO-HCFA, and HO CDI patients at our institution between October 2011 and September 2015. We then performed bivariable analysis on our cohorts to identify differences in time-to-testing and time-to-isolation for CO versus CO-HCFA versus HO CDI patients.355 patients with CDI were hospitalized during the study; 138 (38.9%) with CO CDI, 52 (14.6%) with CO-HCFA CDI, and 165 (46.5%) with HO CDI. 117 (84.8%) CO CDI patients were tested within 1 day of diarrhea onset compared to 41 (78.8%) of CO-HCFA and 113 (68.5%) of HO CDI patients (P.01). 51 CO CDI patients (36.7%) were placed on empirical isolation precautions at the time of diarrhea onset compared to 22 (43.1%) of CO-HCFA CDI patients and 32 (19.4%) of HO CDI patients (P.01).CO CDI patients are more likely to be isolated empirically and tested earlier than HO CDI patients. Further attention should be paid to isolating hospitalized patients who develop diarrhea as an inpatient.

The complement system is a vital component of the innate immune system, though its role in bacteremia is poorly understood. We present complement levels in Staphylococcus aureus bacteremia (SAB) and Gram-negative bacteremia (GNB) and describe observed associations of complement levels with clinical outcomes. Complement and cytokine levels were measured in serum samples from 20 hospitalized patients with SAB, 20 hospitalized patients with GNB, 10 non-infected hospitalized patients, and 10 community controls. C5a levels were significantly higher in patients with SAB as compared to patients with GNB. Low C4 and C3 levels were associated with septic shock and 30-day mortality in patients with GNB, and elevated C3 was associated with a desirable outcome defined as absence of (1) septic shock, (2) acute renal failure, and (3) death within 30 days of bacteremia. Low levels of C9 were associated with septic shock in patients with GNB but not SAB. Elevated IL-10 was associated with increased 30-day mortality in patients with SAB. Complement profiles differ in patients with SAB and those with GNB. Measurement of IL-10 in patients with SAB and of C4, C3, and C9 in patients with GNB may help to identify those at higher risk for poor outcomes. Electronic supplementary material The online version of this article (10.1007/s10096-020-03955-z) contains supplementary material, which is available to authorized users.

Background To understand the clinical, bacterial, and host characteristics associated with recurrent Staphylococcus aureus bacteremia (R-SAB), patients with R-SAB were compared to contemporaneous patients with a single episode of SAB (S-SAB). Methods All SAB isolates underwent spa genotyping. All isolates from R-SAB patients underwent pulsed-field gel electrophoresis (PFGE). PFGE-indistinguishable pairs from 40 patients underwent whole genome sequencing (WGS). Acute phase plasma from R-SAB and S-SAB patients was matched 1:1 for age, race, sex, and bacterial genotype, and underwent cytokine quantification using 25-analyte multiplex bead array. Results R-SAB occurred in 69 (9.1%) of the 756 study patients. Of the 69 patients, 30 experienced relapse (43.5%) and 39 reinfection (56.5%). Age, race, hemodialysis dependence, presence of foreign body, methicillin-resistant Staphyloccus aureus, and persistent bacteremia were individually associated with likelihood of recurrence. Multivariate risk modeling revealed that black hemodialysis patients were nearly 2 times more likely (odds ratio [OR] = 9.652 [95% confidence interval [CI], 5.402–17.418]) than white hemodialysis patients (OR = 4.53 [95% CI, 1.696–10.879]) to experience R-SAB. WGS confirmed PFGE interpretations in all cases. Median RANTES (regulated on activation, normal T cell expressed and secreted) levels in acute phase plasma from the initial episode of SAB were higher in R-SAB than in matched S-SAB controls (P = .0053, false discovery rate Conclusion This study identified several risk factors for R-SAB. The largest risk for R-SAB is among black hemodialysis patients. Higher RANTES levels in R-SAB compared to matched controls warrants further study.

Significance The severity and duration of methicillin-resistant Staphylococcus aureus (MRSA) bacteremia varies widely between individuals. Host factors predisposing to persistent MRSA bacteremia are poorly understood, although genetic association studies are beginning to identify potentially influential variants. We found an association between the A/C heterozygous genotype in the DNMT3A correlating with shorter time to resolution of MRSA bacteremia. Using in vitro macrophage assays and murine sepsis models, we demonstrated that DNMT3A variants may alter host response to infection through increased methylation of key regulatory genes, resulting in reduced interleukin-10 production and in turn, allowing for a more protective immune response that clears infection. An improved understanding of the factors predisposing to persistent MRSA bacteremia may help to discover better treatment options., The role of the host in development of persistent methicillin-resistant Staphylococcus aureus (MRSA) bacteremia is not well understood. A cohort of prospectively enrolled patients with persistent methicillin-resistant S. aureus bacteremia (PB) and resolving methicillin-resistant S. aureus bacteremia (RB) matched by sex, age, race, hemodialysis status, diabetes mellitus, and presence of implantable medical device was studied to gain insights into this question. One heterozygous g.25498283A > C polymorphism located in the DNMT3A intronic region of chromosome 2p with no impact in messenger RNA (mRNA) expression was more common in RB (21 of 34, 61.8%) than PB (3 of 34, 8.8%) patients (P = 7.8 × 10−6). Patients with MRSA bacteremia and g.25498283A > C genotype exhibited significantly higher levels of methylation in gene-regulatory CpG island regions (Δmethylation = 4.1%, P < 0.0001) and significantly lower serum levels of interleukin-10 (IL-10) than patients with MRSA bacteremia without DNMT3A mutation (A/C: 9.7038 pg/mL vs. A/A: 52.9898 pg/mL; P = 0.0042). Expression of DNMT3A was significantly suppressed in patients with S. aureus bacteremia and in S. aureus-challenged primary human macrophages. Small interfering RNA (siRNA) silencing of DNMT3A expression in human macrophages caused increased IL-10 response upon S. aureus stimulation. Treating macrophages with methylation inhibitor 5-Aza-2′-deoxycytidine resulted in increased levels of IL-10 when challenged with S. aureus. In the murine sepsis model, methylation inhibition increased susceptibility to S. aureus. These findings indicate that g.25498283A > C genotype within DNMT3A contributes to increased capacity to resolve MRSA bacteremia, potentially through a mechanism involving increased methylation of gene-regulatory regions and reduced levels of antiinflammatory cytokine IL-10.

Background We conducted a longitudinal study to evaluate changes in the clinical presentation and epidemiology of Staphylococcus aureus bacteremia (SAB) in an academic, US medical center. Methods Consecutive patients with monomicrobial SAB were enrolled from January 1995 to December 2015. Each person’s initial bloodstream S. aureus isolate was genotyped using spa typing. Clonal complexes (CCs) were assigned using Ridom StaphType software. Changes over time in both the patient and bacterial characteristics were estimated with linear regression. Associations between genotypes or clinical characteristics and complications were estimated using multivariable regression models. Results Among the 2348 eligible participants, 54.2% had an implantable, foreign body of some type. This proportion increased significantly during the 21-year study period, by 0.96% annually (P = .002), as did comorbid conditions and acquisition outside of the hospital. Rates of any metastatic complication also significantly increased, by 0.94% annually (P = .019). Among the corresponding bloodstream S. aureus isolates, spa-CC012 (multi-locus sequence type [MLST] CC30), -CC004 (MLST CC45), -CC189 (MLST CC1), and -CC084 (MLST CC15) all significantly declined during the study period, while spa-CC008 (MLST CC8) significantly increased. Patients with SAB due to spa-CC008 were significantly more likely to develop metastatic complications in general, and abscesses, septic emboli, and persistent bacteremia in particular. After adjusting for demographic, racial, and clinical variables, the USA300 variant of spa-CC008 was independently associated with metastatic complications (odds ratio 1.42; 95% confidence interval 1.02–1.99). Conclusions Systematic approaches for monitoring complications of SAB and genotyping the corresponding bloodstream isolates will help identify the emergence of hypervirulent clones and likely improve clinical management of this syndrome.

The contribution of respiratory viruses to acute febrile illness (AFI) burden is poorly characterized. We describe the prevalence, seasonality, and clinical features of respiratory viral infection among AFI admissions in Sri Lanka. We enrolled AFI patients ≥ 1 year of age admitted to a tertiary care hospital in southern Sri Lanka, June 2012-October 2014. We collected epidemiologic/clinical data and a nasal or nasopharyngeal sample that was tested using polymerase chain reaction (Luminex NxTAG, Austin, TX). We determined associations between weather data and respiratory viral activity using the Spearman correlation and assessed respiratory virus seasonality using a Program for Appropriate Technology definition. Bivariable and multivariable regression analyses were conducted to identify features associated with respiratory virus detection. Among 964 patients, median age was 26.2 years (interquartile range 14.6-39.9) and 646 (67.0%) were male. One-fifth (203, 21.1%) had respiratory virus detected: 13.9% influenza, 1.4% human enterovirus/rhinovirus, 1.4% parainfluenza virus, 1.1% respiratory syncytial virus, and 1.1% human metapneumovirus. Patients with respiratory virus identified were younger (median 9.8 versus 27.7 years, P < 0.001) and more likely to have respiratory signs and symptoms. Influenza A and respiratory viral activity peaked in February-June each year. Maximum daily temperature was associated with influenza and respiratory viral activity (P = 0.03 each). Patients with respiratory virus were as likely as others to be prescribed antibiotics (55.2% versus 52.6%, P = 0.51), and none reported prior influenza vaccination. Respiratory viral infection was a common cause of AFI. Improved access to vaccines and respiratory diagnostics may help reduce disease burden and inappropriate antibiotic use.

Background Long-term data on outcomes of participants hospitalized with heart failure (HF) from low- and middle-income countries are limited. Methods and Results In the Trivandrum Heart Failure Registry (THFR) in 2013, 1205 participants from 18 hospitals in Trivandrum, India, were enrolled. Data were collected on demographics, clinical presentation, treatment, and outcomes. We performed survival analyses, compared groups and evaluated the association between heart failure (HF) type and mortality, adjusting for covariates that predicted mortality in a global HF risk score. The mean (standard deviation) age of participants was 61.2 (13.7) years. Ischemic heart disease was the most common cause (72%). The in-hospital mortality rate was higher for participants with HF with reduced ejection fraction (HFrEF; 9.7%) compared with those with HF with preserved ejection fraction (HFpEF; 4.8%; P = .003). After 3 years, 540 (44.8%) participants had died. The all-cause mortality rate was lower for participants with HFpEF (40.8%) compared with HFrEF (46.2%; P = .049). In multivariable models, older age (hazard ratio [HR] 1.24 per decade, 95% confidence interval [CI] 1.15-1.33), New York Heart Association functional class IV symptoms (HR 2.80, 95% CI 1.43-5.48), and higher serum creatinine (HR 1.12 per mg/dL, 95% CI 1.04-1.22) were associated with all-cause mortality. Conclusions Participants with HF in the THFR have high 3-year all-cause mortality. Targeted hospital-based quality improvement initiatives are needed to improve survival during and after hospitalization for HF.

Background Microbial cell-free DNA (mcfDNA) sequencing of plasma can identify the presence of a pathogen in a host. In this study, we evaluated the duration of pathogen detection by mcfDNA sequencing vs conventional blood culture in patients with bacteremia. Methods Blood samples from patients with culture-confirmed bloodstream infection were collected within 24 hours of the index positive blood culture and 48 to 72 hours thereafter. mcfDNA was extracted from plasma, and next-generation sequencing was applied. Reads were aligned against a curated pathogen database. Statistical significance was defined with Bonferroni adjustment for multiple comparisons (P Results A total of 175 patients with Staphylococcus aureus bacteremia (n = 66), gram-negative bacteremia (n = 74), or noninfected controls (n = 35) were enrolled. The overall sensitivity of mcfDNA sequencing compared with index blood culture was 89.3% (125 of 140), and the specificity was 74.3%. Among patients with bacteremia, pathogen-specific mcfDNA remained detectable for significantly longer than conventional blood cultures (median 15 days vs 2 days; P Conclusions Pathogen mcfDNA identified the bacterial etiology of bloodstream infection for a significantly longer interval than conventional cultures, and its duration of detection was associated with increased risk for metastatic infection. mcfDNA could play a role in the diagnosis of partially treated endovascular infections.

This study evaluated the impact of didactic videos and service user testimonial videos on mental illness stigma among medical students. Two randomized controlled trials were conducted in Nepal. Study 1 examined stigma reduction for depression. Study 2 examined depression and psychosis. Participants were Nepali medical students (Study 1:n=94, Study 2:¬n=213) randomized to three conditions: a didactic video based on the mental health Gap Action Programme (mhGAP), a service user video about living with mental illness, or a control condition with no videos. In Study 1, videos only addressed depression. In Study 2, videos addressed depression and psychosis. In Study 1, both didactic and service user videos reduced stigma compared to the control (F2,91=6.37, p=0.003). In Study 2 (depression and psychosis), there were no differences among the three arms (F2,210=2.07, p=0.13). When comparing Study 1 and 2, there was greater stigma reduction in the service user video arm with only depression versus service user videos with depression and psychosis (t(31)=-3.04, p=0.005). In summary, didactic and service user videos were associated with decreased stigma when content addressed only depression. However, no stigma reduction was seen when including depression and psychosis. This calls for different strategies based on types of mental illnesses. ClinicalTrials.gov identifier: NCT03231761

Preventing burnout and promoting positive mental health among medical students is important. Relevant research is lacking on positive mental health in medical students, particularly in low- and middle-income countries. We conducted a cross-sectional survey of Sri Lankan students enrolled in a five-year medical program. Measures included the Mental Health Continuum-Short Form, Kessler 10 Psychological Distress Scale, and Oldenburg Burnout Inventory. We investigated relationships between year in program, mental health indicators, and academic performance. Three hundred twenty-seven students participated (35% response rate). Most students had moderate positive mental health (64.8%) and severe psychological distress (40.4%). Final year students reported more psychological distress and burnout than first year students. Female students had higher burnout scores than males. In multivariable models, fourth and fifth year students evidenced lower positive mental health than first year students. Mental health indicators were unassociated with academic performance. Overall, distress rates were higher than those reported among students in other countries. Higher burnout and distress may be driven by increased responsibilities in the final clinical years of training. Bolstering positive mental health through positive emotions, meaning, and social connection may minimize burnout and distress, although extracurricular activities require time. Interventions to reduce medical student distress in Sri Lanka are needed.

BackgroundWhile factors that drive early mortality among people living with HIV (PLWH) initiating antiretroviral therapy (ART) in sub-Saharan Africa (SSA) have been described, less is known about the predictors of long-term mortality for those with ART experience.MethodsPLWH and on ART attending two HIV treatment clinics in Moshi, Tanzania were enrolled from 2008 through 2009 and followed for 3.5 years. Demographic, psychosocial, and clinical information were collected at enrollment. Plasma HIV RNA measurements were collected annually. Cause of death was adjudicated by two independent reviewers based on verbal autopsy information and medical records. Bivariable and multivariable analyses were conducted using Cox proportional hazard models to identify predictors of mortality.ResultsThe analysis included 403 participants. The median (IQR) age in years was 42 (36-48) and 277 (68.7%) participants were female. The proportion of participants virologically suppressed during the 4 collection time points was 88.5%, 94.7%, 91.5%, and 94.5%. During follow-up, 24 participants died; the overall mortality rate was 1.8 deaths per 100 person-years. Of the deaths, 14 (58.3%) were suspected to be HIV/AIDS related. Predictors of mortality (adjusted hazard ratio, 95% confidence interval) were male sex (2.63, 1.01-6.83), secondary or higher education (7.70, 3.02-19.60), receiving care at the regional referral hospital in comparison to the larger zonal referral hospital (6.33, 1.93-20.76), and moderate to severe depression symptoms (6.35, 1.69-23.87).ConclusionsAs ART coverage continues to expand in SSA, HIV programs should recognize the need for interventions to promote HIV care engagement for men and the integration of mental health screening and treatment with HIV care. Facility-level barriers may contribute to challenges faced by PLWH as they progress through the HIV care continuum, and further understanding of these barriers is needed. The association of higher educational attainment with mortality merits further investigation.

Rationale & Objective Staphylococcus aureus (S aureus) bacteremia (SAB) is associated with morbidity and mortality in patients receiving maintenance hemodialysis (HD). We evaluated changes in clinical and bacterial characteristics, and their associations with clinical outcomes with SAB in this population over a 21-year period. Study Design Prospective cohort study. Setting & Participants 453 hospitalized, non-neutropenic adults receiving maintenance HD who developed monomicrobial SAB between 1995 and 2015. Exposure Clinical characteristics and bacterial genotype. Outcome All-cause and SAB-attributable mortality, persistent bacteremia, and metastatic complications. Analytical Approach Proportions of participants experiencing each outcome were calculated overall and by calendar year. Secular trends were estimated using binomial risk regression, a generalized linear model with the log link function for a binomial outcome. Associations with outcomes were estimated using logistic regression. Results Over the 21-year study period, patients receiving maintenance HD experienced significant increases in age- and diabetes-adjusted SAB-attributable mortality (0.45% [95% CI, 0.36%-0.46%] per year), persistent bacteremia (0.86% [95% CI, 0.14%-1.55%] per year), metastatic complications (0.84% [95% CI, 0.11%-1.56%] per year), and infection with the virulent S aureus clone USA300 (1.47% [95% CI, 0.33%-2.52%] per year). Over time, the suspected source of SAB was less likely to be a central venous catheter (−1.32% [95% CI, −2.05 to −0.56%] per year) or arteriovenous graft (−1.08% [95% CI, −1.54 to −0.56] per year), and more likely to be a nonvascular access source (1.89% [95% CI, 1.29%-2.43%] per year). Patients with a nonvascular access suspected source of infection were more likely to die as a result of their S aureus infection (OR, 3.20 [95% CI, 1.36-7.55]). The increase in USA300 infections may have contributed to the observed increase in persistent bacteremia (OR, 2.96 [95% CI, 1.12-7.83]) but did not explain the observed increases in SAB-attributable mortality (OR, 0.83 [95% CI, 0.19-3.61]) or metastatic complications (OR, 1.34 [95% CI, 0.53-3.41]). Limitations Single-center, inpatient cohort. Conclusions The clinical and molecular epidemiology of SAB in patients receiving maintenance HD has changed over time, with an increase in SAB-attributable mortality and morbidity despite a decline in catheter-related infections.

Objectives:Enterobacter aerogenes was recently renamed Klebsiella aerogenes. This study aimed to identify differences in clinical characteristics, outcomes, and bacterial genetics among patients with K. aerogenes versus Enterobacter species bloodstream infections (BSI). Methods: We prospectively enrolled patients with K. aerogenes or Enterobacter cloacae complex (Ecc) BSI from 2002-2015. We performed whole genome sequencing (WGS) and pan-genome analysis on all bacteria. Results: Overall, 150 patients with K. aerogenes (46/150 [31%]) or Ecc (104/150 [69%]) BSI were enrolled. The two groups had similar baseline characteristics. Neither total in-hospital mortality (13/46 [28%] versus 22/104 [21%]; p=0.3) nor attributable in-hospital mortality (9/46 [20%] versus 13/104 [12%]; p=0.3) differed between patients with K. aerogenes versus Ecc BSI, respectively. However, poor clinical outcome (death before discharge, recurrent BSI, and/or BSI complication) was higher for K. aerogenes than Ecc BSI (32/46 [70%] versus 42/104 [40%]; p=0.001). In a multivariable regression model, K. aerogenes BSI, relative to Ecc BSI, was predictive of poor clinical outcome (odds ratio 3.3; 95% confidence interval 1.4-8.1; p=0.008). Pan-genome analysis revealed 983 genes in 323 genomic islands unique to K. aerogenes isolates, including putative virulence genes involved in iron acquisition (n=67), fimbriae/pili/flagella production (n=117), and metal homeostasis (n=34). Antibiotic resistance was largely found in Ecc lineage 1, which had a higher rate of multidrug resistant phenotype (23/54 [43%]) relative to all other bacterial isolates (23/96 [24%]; p=0.03). Conclusions:K. aerogenes BSI was associated with poor clinical outcomes relative to Ecc BSI. Putative virulence factors in K. aerogenes may account for these differences.

Background: Response-guided hepatitis C therapy was standard with interferon-based regimens but is not used for direct-acting antivirals (DAAs). Week 4 viral kinetics may predict sustained virological response (SVR) with DAAs, but it is unclear whether extending therapy in slow responders affects outcomes. Objectives: The primary objective was to compare SVR rates between traditional and extended duration groups. Secondary objectives were to compare SVR rates among subgroups and to determine factors associated with SVR. Methods: This institutional review board–approved, retrospective, single-center study identified patients with chronic hepatitis C virus (HCV) infection with detectable week 4 HCV RNA who were treated with DAAs. Patients were excluded for early discontinuation, treatment regimen not recommended first-line, or missing HCV RNA labs. Patients were stratified into traditional and extended duration groups. The primary end point was SVR. Secondary end points included factors associated with SVR and rationale for extension of therapy duration. Results: A total of 363 patients were included; 58 (16%) received extended therapy. Patients were primarily genotype 1a (70%) and treatment naïve (80%). More than half had advanced fibrosis or cirrhosis. SVR12 rates were 100% in the extended duration group and 96.7% in the traditional duration group ( P = 0.37). There were no associations with SVR and prespecified patient-specific factors. Sample size was limited. Conclusion and Relevance: Based on these findings, a recommendation for extension of therapy cannot be made for patients with detectable HCV RNA at week 4 of treatment at this time. Cost analyses may help guide recommendations to re-treat rare failures versus extend therapy in all slow responders.

Background While highly preventable, cervical cancer remains a leading contributor to the global burden of cancer among women globally, with disproportionate impacts in Sub-Saharan Africa. Human papillomavirus (HPV) testing is a cost-effective screening strategy with the potential to increase screening uptake; however, the two-visit requirement often leads to substantial loss-to-follow-up (LTFU) for treatment. Understanding modifiable factors that contribute to LTFU is essential to ensuring maximal program impact. Methods We carried out a mixed-methods study to understand factors related to LTFU following an HPV-based cervical cancer screening campaign in rural Western Kenya. We randomly selected participants among women testing HPV positive as part of an existing intervention study to complete quantitative surveys, seeking equal numbers of treated and LTFU women. A subset of women from both groups was selected for in-depth interviews (IDIs). Results Sixty-one treated and 39 LTFU women completed the quantitative survey, and 10 women from each group completed IDIs. Cost of transportation and distance to the hospital were barriers among all women, who often depended on their partners to facilitate this. Among treated women 67% (n = 41) reported that their peers knew their HPV test result, compared to 38% (n = 15) among LTFU women (p = .007). Stigma and lack of partner and peer support emerged as strong barriers among LTFU women. Women proposed peer encouragement, including men in educational sessions, bringing facilities closer, and providing transportation as facilitators to treatment access. Conclusion Lack of partner and social support emerged as key barriers to treatment uptake among LTFU women. Future interventions should explore stigma reduction, male involvement, peer support, and alternative transportation options as potential facilitators to treatment seeking.

Background Previous studies have reported an association of proton pump inhibitor (PPI) use and decreased sustained viral response rate (SVR) in patients taking ledipasvir/sofosbuvir (LDV/SOF). The relationship between PPI usage and SVR is less clear in patients with HIV/HCV coinfection, where concomitant antiretrovirals may result in more complex drug interactions. Aims Evaluate the effects of acid suppression medications (PPI or H2 -receptor antagonist [H2 B]) use and SVR rates in patients with HIV/HCV or HCV and taking LDV/SOF in a large multi-center veteran cohort. Methods Retrospective analysis of all veterans in the Veterans Affairs Health Care System who received LDV/SOF ± ribavirin from 10/10/2014 to 12/31/2015. The odds ratios (OR) of PPI or H2 B use for SVR were adjusted for clinical factors and with inverse probability of treatment weighting for non-random treatment selection for acid suppression medication use. Results There were 9703 veterans included in our final analysis. After adjustment of other clinical factors, PPI use is associated with a lower SVR in the overall cohort (95.0% vs. 96.1%, OR:0.86, 95% CI: 0.74-0.99, P=0.03, number needed to harm 90.9) and HIV/HCV co-infection subgroup (93.4% vs. 96.9%, OR:0.47, 95% CI: 0.26-0.85, P=0.01, number needed to harm 28.6). Conclusion PPI use is associated with reduced SVR after LDV/SOF treatment, with a more significant impact in the subgroup of patients with HIV/HCV coinfection. Precautions need to be taken when using PPI and LDV/SOF in this group of patients.

Background Meningitis caused by methicillin resistant Staphylococcus aureus (MRSA) is rare and often fatal. The recommended treatment for MRSA meningitis, vancomycin, is limited by poor cerebrospinal fluid (CSF) penetration. Ceftaroline fosamil is a novel fifth-generation cephalosporin with potent antibacterial activity in vitro against MRSA. Several case reports in humans suggest that ceftaroline might be a potential treatment option for MRSA meningitis. Our primary objective was to com­pare the efficacy of ceftaroline and vancomycin for the treatment of MRSA meningitis using a rabbit meningitis model. We then characterized CSF drug concentrations over time.Methods Ninety rabbits received a direct intracisternal injection of 5 x 105 CFU S. aureus (MRSA 252). Following a 16-hour incubation period, approximately 0.5ml of CSF was withdrawn via intracisternal aspiration immediately prior to treatment for quantitative bacterial counts and CSF antibiotic concentrations. Rabbits then received (by 1:1:1 random assignment) either no treatment (control group), vancomycin 20 mg/kg at 0 and 12hrs, or ceftaroline 40mg/kg at 0 and 4 hrs via marginal ear vein. CSF collection was repeated every 12 hours for up to 40 hours. All animals were humanely euthanized at 40 hours post inoculation. The primary endpoint (difference in bacterial load [expressed as CFU/mL] for each animal between the initial (T1) and terminal (T3) taps were characterized and compared between groups using the Kruskal-Wallis test. CSF drug concentrations were determined using liquid chromatography with tandem mass spectrometry (LC/MS/MS) assay.ResultsAmong the forty-three evaluable animals with established MRSA meningitis, there was no statistical difference in median CFU observed between the groups in pretreatment CFU counts (p=0.16). Reductions in bacterial load from baseline were 88%, 79% and 75% in the control, ceftaroline and vancomycin-treated groups, respectively. There was no statistical difference observed between vancomycin and either control or ceftaroline at any time point. While animals treated with ceftaroline exhibited a significant increase in clearance rate (log ∆) between T1 and T2 when compared to control (p = 0.019), these differences were no longer statistically significant by T3 (p= 0.43) as CSF ceftaroline concentrations were undetectable by that time point.Conclusions While ceftaroline may be a reasonable alternative to vancomycin for MRSA meningitis, additional animal and clinical studies are required to determine optimal dosing to establish its effectiveness.

ObjectiveTo identify health systems-level barriers to treatment for women who screened positive for high-risk human papillomavirus (hrHPV) in a cervical cancer prevention program in Kenya.MethodsIn a trial of implementation strategies for hrHPV-based cervical cancer screening in western Kenya in 2018-2019, women underwent hrHPV testing offered through community health campaigns, and women who tested positive were referred to government health facilities for cryotherapy. The current analysis draws on treatment data from this trial, as well as two observational studies that were conducted: 1) periodic assessments of the treatment sites to ascertain availability of resources for treatment and 2) surveys with treatment providers to elicit their views on barriers to care. Bivariate analyses were performed for the site assessment data, and the provider survey data were analyzed descriptively.ResultsSeventeen site assessments were performed across three treatment sites. All three sites reported instances of supply stockouts, two sites reported treatment delays due to lack of supplies, and two sites reported treatment delays due to provider factors. Of the 16 providers surveyed, ten (67%) perceived lack of knowledge of HPV and cervical cancer as the main barrier in women's decision to get treated, and seven (47%) perceived financial barriers for transportation and childcare as the main barrier to accessing treatment. Eight (50%) endorsed that providing treatment free of cost was the greatest facilitator of treatment.ConclusionPatient education and financial support to reach treatment are potential areas for intervention to increase rates of hrHPV+ women presenting for treatment. It is also essential to eliminate barriers that prevent treatment of women who present, including ensuring adequate supplies and staff for treatment.

Summary Background Early and accurate identification of individuals with viral infections is crucial for clinical management and public health interventions. We aimed to assess the ability of transcriptomic biomarkers to identify naturally acquired respiratory viral infection before typical symptoms are present. Methods In this index-cluster study, we prospectively recruited a cohort of undergraduate students (aged 18–25 years) at Duke University (Durham, NC, USA) over a period of 5 academic years. To identify index cases, we monitored students for the entire academic year, for the presence and severity of eight symptoms of respiratory tract infection using a daily web-based survey, with symptoms rated on a scale of 0–4. Index cases were defined as individuals who reported a 6-point increase in cumulative daily symptom score. Suspected index cases were visited by study staff to confirm the presence of reported symptoms of illness and to collect biospecimen samples. We then identified clusters of close contacts of index cases (ie, individuals who lived in close proximity to index cases, close friends, and partners) who were presumed to be at increased risk of developing symptomatic respiratory tract infection while under observation. We monitored each close contact for 5 days for symptoms and viral shedding and measured transcriptomic responses at each timepoint each day using a blood-based 36-gene RT-PCR assay. Findings Between Sept 1, 2009, and April 10, 2015, we enrolled 1465 participants. Of 264 index cases with respiratory tract infection symptoms, 150 (57%) had a viral cause confirmed by RT-PCR. Of their 555 close contacts, 106 (19%) developed symptomatic respiratory tract infection with a proven viral cause during the observation window, of whom 60 (57%) had the same virus as their associated index case. Nine viruses were detected in total. The transcriptomic assay accurately predicted viral infection at the time of maximum symptom severity (mean area under the receiver operating characteristic curve [AUROC] 0·94 [95% CI 0·92–0·96]), as well as at 1 day (0·87 [95% CI 0·84–0·90]), 2 days (0·85 [0·82–0·88]), and 3 days (0·74 [0·71–0·77]) before peak illness, when symptoms were minimal or absent and 22 (62%) of 35 individuals, 25 (69%) of 36 individuals, and 24 (82%) of 29 individuals, respectively, had no detectable viral shedding. Interpretation Transcriptional biomarkers accurately predict and diagnose infection across diverse viral causes and stages of disease and thus might prove useful for guiding the administration of early effective therapy, quarantine decisions, and other clinical and public health interventions in the setting of endemic and pandemic infectious diseases. Funding US Defense Advanced Research Projects Agency.

BACKGROUND Naloxone-an opioid antagonist that reverses the effects of opioids-is increasingly being distributed in non-medical settings. We sought to identify the facilitators of, and barriers to, opioid users using naloxone kits in North Carolina.METHODS In 2015, we administered a 15-item survey to a convenience sample of 100 treatment seekers at 4 methadone/buprenorphine Medication Assisted Therapy (MAT) clinics in North Carolina.RESULTS Seventy-four percent of participants reported having ever gotten a naloxone kit; this percentage was higher for females (81%) than males (63%) (P = .06). The primary reason given for not having a kit was not knowing where to get one. Only 6% had heard of kits from the media and only 5% received one from a medical provider. Among kit recipients, 56% of both females and males reported mostly or sometimes carrying the kit, with additional participants reporting always. Reasons for not carrying a kit were no longer being around drugs, forgetting it, and the kit being too large. Men discussed the difficulties of carrying the naloxone kits, which are currently too large to fit in a pocket. Ninety-four percent of naloxone users reported intending to call emergency services in case of an overdose emergency.LIMITATIONS Study limitations included a small sample, participants limited to MAT clinics, and a predominantly white sample.CONCLUSIONS MAT treatment seekers reported a willingness to carry and use naloxone kits. Education, outreach, media, and medical providers need to promote naloxone kits. A smaller kit may increase the likelihood of men carrying one.

Background Staphylococcus aureus biofilms are a common cause of persistent, life-threatening infections. Dispersal of S. aureus cells from established biofilm-based infections is crucial for dissemination within the host, but is poorly understood. We tested the hypothesis that biofilm dispersed S. aureus cells have distinct physiology from planktonic cells and are better equipped to evade host immunity in an agr-dependent manner. Methods Primary murine bone marrow-derived macrophages (BMDMs) were infected with planktonic and biofilm dispersed cells from S. aureus USA300 LAC wild type (WT) and USA300 LAC-agr knockout (KO). Biofilm dispersed cells were collected via glucose deprivation. Gentamicin protection assays were used to enumerate phagocytosed bacteria and fluorescence microscopy to quantify macrophage viability. A 26-plex immunoassay was used to screen for cytokines and chemokines. Reversed phase high-performance liquid chromatography was used to measure relative phenol-soluble modulin (PSM) levels from macrophage co-cultures. Results Compared with planktonic cells, biofilm-dispersed cells in both S. aureus WT and KO backgrounds exhibited: (1) ~10-fold less phagocytosis by BMDMs (p = 0.0003; Figure 1); (2) increased macrophage killing (23% vs. 8%; p = 0.0038; Figure 2); (3) stronger pro- (e.g., IFN-y, IL-2, IL-6, IL-17; Figure 3A) and anti- (e.g., IL-10, IL-4, IL-22; Figure 3B) inflammatory cytokine responses from macrophages (P < 0.05 for all); (4) significantly higher δ toxin PSM production (P = 0.0090; Figure 4) in WT background only. Conclusion S. aureus biofilm dispersed cells are physiologically distinct from planktonic cells and have a unique interaction with the host immune system. Dispersed cells are more resistant to phagocytosis, have a greater propensity to kill macrophages, and mount stronger pro- and anti-inflammatory responses in an agr-independent manner. Dispersed cells also have the ability to produce more δ toxin PSM via well-known agr-dependent pathways. Disclosures All authors: No reported disclosures.

ObjectivesThe role of follow-up blood cultures (FUBCs) in the management of Gram-negative bacteraemia (GNB) is poorly understood. We aimed to determine the utility of FUBCs in identifying patients with increased mortality risk.MethodsAn observational study with a prospectively enrolled cohort of adult inpatients with GNB was conducted at Duke University Health System from 2002 to 2015. FUBCs were defined as blood cultures performed from 24hours to 7days from initial positive blood culture.ResultsAmong 1702 patients with GNB, 1164 (68%) had FUBCs performed. When performed, FUBCs were positive in 20% (228/1113) of cases. FUBC acquisition was associated with lower all-cause in-hospital mortality (108/538, 20%, vs. 176/1164, 15%; p 0.01) and attributable in-hospital mortality (78/538, 15%, vs. 98/1164, 8%; p&nbsp

Background China is thought to be a hotspot for zoonotic influenza virus emergence, yet there have been few prospective studies examining the occupational risks of such infections. Methods We present the first 2 years of data collected from a 5-year, prospective, cohort study of swine-exposed and -unexposed participants at 6 swine farms in China. We conducted serological and virological surveillance to examine evidence for swine influenza A virus infection in humans. Results Of the 658 participants (521 swine-exposed and 137 swine-unexposed), 207 (31.5%) seroconverted against at least 1 swine influenza virus subtype (swine H1N1 or H3N2). Swine-exposed participants’ microneutralization titers, especially those enrolled at confined animal feeding operations (CAFOs), were higher against the swine H1N1 virus than were other participants at 12 and 24 months. Despite elevated titers, among the 187 study subjects for whom we had complete follow-up, participants working at swine CAFOs had significantly greater odds of seroconverting against both the swine H1N1 (odds ratio [OR] 19.16, 95% confidence interval [CI] 3.55–358.65) and swine H3N2 (OR 2.97, 95% CI 1.16–8.01) viruses, compared to unexposed and non-CAFO swine workers with less intense swine exposure. Conclusions While some of the observed increased risk against swine viruses may have been explained by exposure to human influenza strains, study data suggest that even with elevated preexisting antibodies, swine-exposed workers were at high risk of infection with enzootic swine influenza A viruses., A 2-year (2015–2017) prospective cohort study of 187 swine workers in China revealed that swine workers were at increased risk of infection with the endemic swine influenza A viruses, despite having preexisting elevated neutralizing antibodies against these viruses.

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Background: In patients with active infective endocarditis (IE), the relationship between timing of surgery and survival is uncertain. The objective was to evaluate clinical characteristics associated with timing of surgery and the association between surgical timing and 6-month survival in complicated, left-sided IE. Methods: In a prospective, multicenter, observational registry (The International Collaboration on Endocarditis-PLUS, registry from 2008 to 2012), clinical factors associated with timing of surgery during the index hospitalization were determined among 485 adult patients with definite, complicated, left-sided IE who underwent cardiac surgery during their index hospitalization. The relationship between early surgical intervention (

Background Concomitant dosing of ledipasvir (LDV) and tenofovir disoproxil fumarate (TDF) results in an increased tenofovir (TFV) area under the curve (AUC). The aim of this study was to examine whether there was a correlation between the renal biomarkers retinol binding protein–4 (RBP-4) and β2 microglobulin (β2M) and tenofovir AUC. Methods The ION-4 trial enrolled HIV/hepatitis C virus–coinfected patients on nonpharmacologically boosted antiretroviral regimens with TDF-containing backbones. We assessed for a correlation between tenofovir AUC and urinary biomarkers and also for changes in serologic biomarkers with respect to clinically relevant changes in renal function (creatinine clearance decrease >25%, change in creatinine >0.2 mg/dL, change in proteinuria from negative/trace to ≥1+). Results Three hundred thirty-five patients were enrolled in the ION-4 study; their demographic characteristics have been previously described. Both RBP-4 and β2M exhibited positive correlations with tenofovir AUC. Baseline and study levels of RBP-4 and β2M were higher for patients with increases in urine proteinuria and an absolute creatinine increase. Conclusions TFV exposure is associated with increased proximal tubule urine biomarkers in participants on ledipasvir/sofosbuvir and nonpharmacologically boosted TDF-based antiretroviral regimens. Baseline proximal tubule biomarkers may predict nephrotoxicity risk if events are prevalent. Further studies assessing the predictive role of these urine biomarkers may help guide medical decision-making and risk/benefit assessments in patients with risk factors for renal dysfunction.

Background Hematogenous vertebral osteomyelitis (HVOM) is a rare, but devastating complication of Staphylococcus aureus bacteremia (SAB). Risk factors and outcomes associated with HVOM among patients with SAB remain incompletely understood. Methods All adult, hospitalized, non-neutropenic patients with SAB were prospectively enrolled from 1995 to 2015. Additional data was subsequently collected on all patients with HVOM. Diagnosis of HVOM was made either radiographically or microbiologically by culture from the infection site. Patients who underwent lumbar puncture or spinal surgery within 30 days prior to the diagnosis of HVOM were excluded. Results Of 2,475 cases of prospectively enrolled patients with SAB, 90 (3.6%) developed HVOM. The most common site of involvement was the lumbar spine (65.6%). MRI was used in the diagnosis of 90% of patients and although only 28.9% underwent bone biopsy, 88.5% of these bone cultures grew S. aureus. Patients with HVOM were more likely to have community-acquired SAB (22.2% vs. 9.9%, P < 0.0001) and persistent bacteremia (47.8% vs. 20.5%, P < 0.0001). Patients with HVOM who required surgical intervention were more likely to have motor deficit (60.9% vs. 21.4%, P = 0.0013) and have associated epidural abscesses (69.6% vs. 44.8%, P = 0.0400). Prolonged antibiotic use for HVOM was common, with 13.3% remaining on therapeutic antibiotics and 16.6% on suppressive therapy at 6 months. This dropped to 2.2% on therapeutic and 15.5% on suppressive therapy at 12 months. All-cause mortality was high in the HVOM cohort at 14.4% at 90-days, increasing to a cumulative 18.9% and 20.0% at 6 and 12-months, respectively. Rates of readmission, recurrent bacteremia, paralysis, and mortality at 6 and 12-months were similar for those who required surgical intervention and those who did not. Demographics, comorbidities, and clinical characteristics of patients with and without hematogenous vertebral osteomyelitis (HVOM) Conclusion HVOM in patients with SAB was associated with high rates of all-cause mortality up to 12 months following date of diagnosis. Patients with community-acquired bacteremia and persistent bacteremia were more likely to develop HVOM. Disclosures Vance G. Fowler, Jr., MD, MHS, Achaogen (Consultant)Actavis (Grant/Research Support)Advanced Liquid Logics (Grant/Research Support)Affinergy (Consultant, Research Grant or Support)Affinium (Consultant)Allergan (Grant/Research Support)Ampliphi Biosciences (Consultant)Basilea (Consultant, Research Grant or Support)Bayer (Consultant)C3J (Consultant)Cerexa (Consultant, Research Grant or Support)Contrafect (Consultant, Research Grant or Support)Cubist (Grant/Research Support)Debiopharm (Consultant)Destiny (Consultant)Durata (Consultant)Forest (Grant/Research Support)Genentech (Consultant, Research Grant or Support)Integrated Biotherapeutics (Consultant)Janssen (Consultant, Research Grant or Support)Karius (Grant/Research Support)Locus (Grant/Research Support)Medical Biosurfaces (Grant/Research Support)Medicines Co. (Consultant)Medimmune (Consultant, Research Grant or Support)Merck (Consultant, Research Grant or Support)NIH (Grant/Research Support)Novadigm (Consultant)Novartis (Consultant, Research Grant or Support)Pfizer (Grant/Research Support)Regeneron (Consultant, Research Grant or Support)Tetraphase (Consultant)Theravance (Consultant, Research Grant or Support)Trius (Consultant)xBiotech (Consultant)

Background Human immunodeficiency virus (HIV) and hepatitis C virus (HCV) infections are associated with increased risk of cardiovascular disease (CVD). The potential impact of recently updated cholesterol guidelines on treatment of HIV- and HCV-infected veterans is unknown. Methods We performed a retrospective cohort study to assess statin use and recommendations among 13 579 HIV-infected, 169 767 HCV-infected, and 6628 HIV/HCV-coinfected male veterans aged 40-75 years. Prior 2004 Adult Treatment Panel (ATP-III) guidelines were compared with current 2013 American College of Cardiology/American Heart Association (ACC/AHA) cholesterol guidelines and 2014 US Department of Veterans Affairs (VA)/US Department of Defense (DoD) joint clinical practice guidelines using laboratory, medication, and comorbidity data from the VA Clinical Case Registry from 2008 through 2010. Results Using risk criteria delineated by the ATP-III guidelines, 50.6% of HIV-infected, 45.9% of HCV-infected, and 33.8% of HIV/HCV-coinfected veterans had an indication for statin therapy. However, among those eligible, 22.7%, 30.5%, and 31.5%, respectively, were not receiving ATP-III recommended statin therapy. When current cholesterol guidelines were applied by VA/DoD and ACC/AHA criteria, increases in recommendations for statins were found in all groups (57.3% and 66.1% of HIV-infected, 64.4% and 73.7% of HCV-infected, 49.1% and 58.5% of HIV/HCV-coinfected veterans recommended). Conclusions Statins were underutilized among veterans infected with HIV, HCV, and HIV/HCV according to previous ATP-III guidelines. Current VA/DoD and ACC/AHA guidelines substantially expand statin recommendations and widen the gap of statin underutilization in all groups. These gaps in care present an opportunity to improve CVD prevention efforts in these at-risk populations.

Alpha-toxin is a major Staphylococcus aureus virulence factor. This study evaluated potential relationships between in vitro alpha-toxin expression of S. aureus bloodstream isolates, anti-alpha-toxin antibody in serum of patients with S. aureus bacteremia (SAB), and clinical outcomes in 100 hemodialysis and 100 postsurgical SAB patients. Isolates underwent spa typing and hla sequencing. Serum anti-alpha-toxin IgG and neutralizing antibody levels were measured by using an enzyme-linked immunosorbent assay and a red blood cell (RBC)-based hemolysis neutralization assay. Neutralization of alpha-toxin by an anti-alpha-toxin monoclonal antibody (MAb MEDI4893) was tested in an RBC-based lysis assay. Most isolates encoded hla (197/200; 98.5%) and expressed alpha-toxin (173/200; 86.5%). In vitro alpha-toxin levels were inversely associated with survival (cure, 2.19 μg/ml, versus failure, 1.09 μg/ml; P < 0.01). Both neutralizing (hemodialysis, 1.26 IU/ml, versus postsurgical, 0.95; P < 0.05) and IgG (hemodialysis, 1.94 IU/ml, versus postsurgical, 1.27; P < 0.05) antibody levels were higher in the hemodialysis population. Antibody levels were also significantly higher in patients infected with alpha-toxin-expressing S. aureus isolates ( P < 0.05). Levels of both neutralizing antibodies and IgG were similar among patients who were cured and those not cured (failures). Sequence analysis of hla revealed 12 distinct hla genotypes, and all genotypic variants were susceptible to a neutralizing monoclonal antibody in clinical development (MEDI4893). These data demonstrate that alpha-toxin is highly conserved in clinical S. aureus isolates. Higher in vitro alpha-toxin levels were associated with a positive clinical outcome. Although patients infected with alpha-toxin-producing S. aureus exhibited higher anti-alpha-toxin antibody levels, these levels were not associated with a better clinical outcome in this study.

We evaluated the syphilis reverse sequence algorithm (RSA) in a Veteran Affairs facility, finding 5.5% reactive Treponema pallidum enzyme immunoassay (EIA) tests. In a subset of EIA+/VDRL-/TP-PA+ cases, 48% were previously treated. Of veterans with unknown/no prior therapy, only 45% had documentation of subsequent treatment, suggesting suboptimal interpretation of RSA results.

The impact of bacterial species on outcome in bloodstream infections (BSI) is incompletely understood. We evaluated the impact of bacterial species on BSI mortality, with adjustment for patient, bacterial, and treatment factors. From 2002 to 2015, all adult inpatients with monomicrobial BSI caused by Staphylococcus aureus or Gram-negative bacteria at Duke University Medical Center were prospectively enrolled. Kaplan-Meier curves and multivariable Cox regression with propensity score models were used to examine species-specific bacterial BSI mortality. Of the 2,659 enrolled patients, 999 (38%) were infected with S. aureus , and 1,660 (62%) were infected with Gram-negative bacteria. Among patients with Gram-negative BSI, Enterobacteriaceae (81% [1,343/1,660]) were most commonly isolated, followed by non-lactose-fermenting Gram-negative bacteria (16% [262/1,660]). Of the 999 S. aureus BSI isolates, 507 (51%) were methicillin resistant. Of the 1,660 Gram-negative BSI isolates, 500 (30%) were multidrug resistant. The unadjusted time-to-mortality among patients with Gram-negative BSI was shorter than that of patients with S. aureus BSI ( P = 0.003), due to increased mortality in patients with non-lactose-fermenting Gram-negative BSI generally ( P < 0.0001) and Pseudomonas aeruginosa BSI ( n = 158) in particular ( P < 0.0001). After adjustment for patient demographics, medical comorbidities, bacterial antibiotic resistance, timing of appropriate antibiotic therapy, and source control in patients with line-associated BSI, P. aeruginosa BSI remained significantly associated with increased mortality (hazard ratio = 1.435; 95% confidence interval = 1.043 to 1.933; P = 0.02). P. aeruginosa BSI was associated with increased mortality relative to S. aureus or other Gram-negative BSI. This effect persisted after adjustment for patient, bacterial, and treatment factors.

We previously showed that chromosome 8 of A/J mice was associated with susceptibility to S. aureus infection. However, the specific genes responsible for this susceptibility are unknown. Chromosome substitution strain 8 (CSS8) mice, which have chromosome 8 from A/J but an otherwise C57BL/6J genome, were used to identify the genetic determinants of susceptibility to S. aureus on chromosome 8. Quantitative trait loci (QTL) mapping of S. aureus-infected N2 backcross mice (F1 [C8A] × C57BL/6J) identified a locus 83180780-88103009 (GRCm38/mm10) on A/J chromosome 8 that was linked to S. aureus susceptibility. All genes on the QTL (n~ 102) were further analyzed by three different strategies: 1) different expression in susceptible (A/J) and resistant (C57BL/6J) mice only in response to S. aureus, 2) consistently different expression in both uninfected and infected states between the two strains, and 3) damaging non-synonymous SNPs in either strain. Eleven candidate genes from the QTL region were significantly differently expressed in patients with S. aureus infection vs healthy human subjects. Four of these 11 genes also exhibited significantly different expression in S. aureus-challenged human neutrophils: Ier2, Crif1, Cd97 and Lyl1. CD97 ligand binding was evaluated within peritoneal neutrophils from A/J and C57BL/6J. CD97 from A/J had stronger CD55 but weaker integrin α5β1 ligand binding as compared with C57BL/6J. Because CD55/CD97 binding regulates immune cell activation and cytokine production, and integrin α5β1 is a membrane receptor for fibronectin, which is also bound by S. aureus, strain-specific differences could contribute to susceptibility to S. aureus. Down-regulation of Crif1 with siRNA was associated with increased host cell apoptosis among both naïve and S. aureus-infected bone marrow-derived macrophages. Specific genes in A/J chromosome 8, including Cd97 and Crif1, may play important roles in host defense against S. aureus.

Respiratory viral infections (RVI) are a frequent cause of morbidity and mortality in hematopoietic stem cell transplant (HSCT) patients. We examined clinical characteristics and respiratory viral detection in asymptomatic pediatric HSCT pre-transplant patients and symptomatic post-transplant patients. Coxsackie/echovirus (most common virus detected pre and post-transplant), rhinovirus, and coronavirus were detected pre-transplant and at the first post-transplant event suggesting persistent detection. None of the clinical characteristics examined were associated with viral detection and there was no increase in mortality noted with asymptomatic viral detection.