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Importance: Oral non-ß-lactam antibiotics are commonly used for empirical therapy of Staphylococcus aureus infections, especially in outpatient settings. However, little is known about potential geographic heterogeneity and temporal trends in the prevalence of S aureus resistance to non-ß-lactams in the US. Objective: To characterize the spatiotemporal trends of resistance to non-ß-lactam antibiotics among community-onset S aureus infections, including regional variation in resistance rates and geographical heterogeneity in multidrug resistance. Design, Setting, and Participants: This cross-sectional study used data from Veterans Health Administration clinics collected from adult outpatients with S aureus infection in the conterminous 48 states and Washington, DC, from January 1, 2010, to December 31, 2019. Data were analyzed from January to November 2023. Exposures: Resistance to lincosamides (clindamycin), tetracyclines, sulfonamides (trimethoprim-sulfamethoxazole [TMP-SMX]), and macrolides. Main Outcomes and Measures: Spatiotemporal variation of S aureus resistance to these 4 classes of non-ß-lactam antibiotics, stratified by methicillin-resistant S aureus (MRSA) and methicillin-sensitive S aureus (MSSA), and subdivided by regions of the US (Northeast, Midwest, South, and West). Trend tests and bivariate mapping were used to determine significant changes in resistant proportions over time and identify counties where rates of resistance to multiple non-ß-lactams were high. Results: A total of 382â¯149 S aureus isolates from 268â¯214 unique outpatients (mean [SD] age, 63.4 [14.8] years; 252â¯910 males [94.29%]) were analyzed. There was a decrease in the proportion of MRSA nationwide, from 53.6% in 2010 to 38.8% in 2019. Among MRSA isolates, we observed a significant increase in tetracycline resistance (from 3.6% in 2010 to 12.8% in 2019; P for trend < .001) and TMP-SMX resistance (from 2.6% in 2010 to 9.2% in 2019; P for trend < .001), modest and not significant increases in clindamycin resistance (from 24.2% in 2010 to 30.6% in 2019; P for trend = .34), and a significant decrease in macrolide resistance (from 73.5% in 2010 to 60.2% in 2019; P for trend < .001). Among MSSA isolates, significant upward trends in clindamycin, tetracyclines, and TMP-SMX resistance were observed. For example, tetracycline resistance increased from 3.7% in 2010 to 9.1% in 2019 (P for trend < .001). Regional stratification over time showed that the Northeast had slightly higher rates of clindamycin resistance but lower rates of tetracycline resistance, while the South had notably higher rates of resistance to tetracyclines and TMP-SMX, particularly among MRSA isolates. Bivariate mapping at the county scale did not indicate clear regional patterns of shared high levels of resistance to the 4 classes of antimicrobials studied. Conclusions and Relevance: In this study of outpatient S aureus isolates, MRSA became less common over the 10-year period, and MRSA isolates were increasingly resistant to tetracyclines and TMP-SMX. Geographic analysis indicated no spatial overlap in counties with high rates of resistance to both tetracyclines and TMP-SMX. Examining the regional spatial variation of antibiotic resistance can inform empirical therapy recommendations and help to understand the evolution of S aureus antibiotic resistance mechanisms.
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Antibacterianos , Pacientes Ambulatorios , Infecciones Estafilocócicas , Staphylococcus aureus , Humanos , Estudios Transversales , Infecciones Estafilocócicas/tratamiento farmacológico , Infecciones Estafilocócicas/epidemiología , Infecciones Estafilocócicas/microbiología , Masculino , Femenino , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/aislamiento & purificación , Persona de Mediana Edad , Antibacterianos/uso terapéutico , Antibacterianos/farmacología , Pacientes Ambulatorios/estadística & datos numéricos , Estados Unidos/epidemiología , Anciano , Adulto , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Farmacorresistencia BacterianaRESUMEN
Importance: Acute kidney injury (AKI) complicates 20% to 25% of hospital admissions and is associated with long-term mortality, especially from cardiovascular disease. Lower systolic blood pressure (SBP) following AKI may be associated with lower mortality, but potentially at the cost of higher short-term complications. Objective: To determine associations of SBP with mortality and hospital readmissions following AKI, and to determine whether time from discharge affects these associations. Design, Setting, and Participants: This retrospective cohort study of adults with AKI during a hospitalization in Veteran Healthcare Association (VHA) hospitals was conducted between January 2013 and December 2018. Patients with 1 year or less of data within the VA system prior to admission, severe or end-stage liver disease, stage 4 or 5 chronic kidney disease, end-stage kidney disease, metastatic cancer, and no blood pressure values within 30 days of discharge were excluded. Data analysis was conducted from May 2022 to February 2024. Exposure: SBP was treated as time-dependent (categorized as <120 mm Hg, 120-129 mm Hg, 130-139 mm Hg, 140-149 mm Hg, 150-159 mm Hg, and ≥160 mm Hg [comparator]). Time spent in each SBP category was accumulated over time and represented in 30-day increments. Main Outcomes and Measures: Primary outcomes were time to mortality and time to all-cause hospital readmission. Cox proportional hazards regression was adjusted for demographics, comorbidities, and laboratory values. To evaluate associations over time, hazard ratios (HRs) were calculated at 60 days, 90 days, 120 days, 180 days, 270 days, and 365 days from discharge. Results: Of 237â¯409 admissions with AKI, 80â¯960 (57â¯242 aged 65 years or older [70.7%]; 77â¯965 male [96.3%] and 2995 female [3.7%]) were included. The cohort had high rates of diabetes (16â¯060 patients [20.0%]), congestive heart failure (22â¯516 patients [28.1%]), and chronic lung disease (27â¯682 patients [34.2%]), and 1-year mortality was 15.9% (12â¯876 patients). Overall, patients with SBP between 130 and 139 mm Hg had the most favorable risk level for mortality and readmission. There were clear, time-dependent mediations on associations in all groups. Compared with patients with SBP of 160 mm Hg or greater, the risk of mortality for patients with SBP between 130 and 139 mm Hg decreased between 60 days (adjusted HR, 1.20; 99% CI, 1.00-1.44) and 365 days (adjusted HR, 0.58; 99% CI, 0.45-0.76). SBP less than 120 mm Hg was associated with increased risk of mortality at all time points. Conclusions and Relevance: In this retrospective cohort study of post-AKI patients, there were important time-dependent mediations of the association of blood pressure with mortality and readmission. These findings may inform timing of post-AKI blood pressure treatment.
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Lesión Renal Aguda , Presión Sanguínea , Readmisión del Paciente , Humanos , Readmisión del Paciente/estadística & datos numéricos , Masculino , Femenino , Lesión Renal Aguda/mortalidad , Estudios Retrospectivos , Anciano , Persona de Mediana Edad , Presión Sanguínea/fisiología , Estados Unidos/epidemiología , Factores de Riesgo , Anciano de 80 o más AñosRESUMEN
BACKGROUND: While the use of cumulative susceptibility reports, antibiograms, is recommended for improved empiric therapy and antibiotic stewardship, the predictive ability of antibiograms has not been well-studied. While enhanced antibiograms have been shown to better capture variation in susceptibility profiles by characteristics such as infection site or patient age, the potential for seasonal or spatial variation in susceptibility has not been assessed as important in predicting likelihood of susceptibility. METHODS: Utilizing Staphylococcus aureus isolates obtained in outpatient settings from a nationwide provider of care, the Veterans Health Administration, and a local provider of care, the University of Iowa Hospitals and Clinics, standard, seasonal and spatial antibiograms were created for five commonly used antibiotic classes: cephalosporins, clindamycin, macrolides, tetracycline, trimethoprim/sulfamethoxazole. RESULTS: A total of 338,681 S. aureus isolates obtained in VHA outpatient settings from 2010 to 2019 and 6,817 isolates obtained in UIHC outpatient settings from 2014 to 2019 were used to generate and test antibiograms. Logistic regression modeling determined the capacity of these antibiograms to predict isolate resistance to each antibiotic class. All models had low predictive capacity, with areas under the curve of < 0.7. CONCLUSIONS: Standard antibiograms are poor in predicting S. aureus susceptibility to antibiotics often chosen by clinicians, and seasonal and spatial antibiograms do not provide an improved tool in anticipating non-susceptibility. These findings suggest that further refinements to antibiograms may be necessary to improve their utility in informing choice of effective antibiotic therapy.
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Antibacterianos , Infecciones Estafilocócicas , Humanos , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Staphylococcus aureus , Pacientes Ambulatorios , Estaciones del Año , Farmacorresistencia Bacteriana , Infecciones Estafilocócicas/tratamiento farmacológico , Pruebas de Sensibilidad MicrobianaRESUMEN
BACKGROUND: Simultaneous liver-kidney transplant (SLK) allocation policy in the United States was revised in August 2017, reducing access for liver transplant candidates with sustained acute kidney injury (sAKI) and potentially adversely impacting vulnerable populations whose true renal function is overestimated by commonly used estimation equations. METHODS: We examined national transplant registry data containing information for all liver transplant recipients from June 2013 to December 2021 to assess the impact of this policy change using instrumental variable estimation based on date of listing. RESULTS: Posttransplant survival was compared for propensity-matched patients with sAKI who were only eligible for liver transplant alone (LTA_post; n = 638) after the policy change but would have been SLK-eligible before August 2017, with similar patients who were previously able to receive an SLK (SLK; n = 319). Overall posttransplant patient survival was similar at 3 y (81% versus 80%; P = 0.9). However, receiving an SLK versus LTA increased survival among African Americans (87% versus 61% at 3 y; P = 0.029). A trend toward survival benefit from SLK versus LTA, especially later in the follow-up period, was observed in recipients ≥ age 60 (3-y survival: 84% versus 76%; P = 0.2) and women (86% versus 80%; P = 0.2). CONCLUSIONS: The 2017 United Network for Organ Sharing SLK Allocation Policy was associated with reduced survival of African Americans with end-stage liver disease and sAKI and, potentially, older patients and women. Our study suggested the use of race-neutral estimation of renal function would ameliorate racial disparities in the SLK arena; however, further studies are needed to reduce disparity in posttransplant outcomes among patients with liver and kidney failure.
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Lesión Renal Aguda , Trasplante de Riñón , Humanos , Femenino , Estados Unidos , Persona de Mediana Edad , Trasplante de Riñón/efectos adversos , Factores de Riesgo , Riñón , Lesión Renal Aguda/etiología , Hígado , Políticas , Estudios RetrospectivosRESUMEN
Using data from the Veterans' Health Administration from 2010 to 2019, we examined the distribution and prevalence of community-acquired phenotypic extended-spectrum ß-lactamase (ESBL) E. coli in the United States. ESBL prevalence slowly increased during the study period, and cluster analysis showed clustering in both urban and rural locations.
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Infecciones Comunitarias Adquiridas , Infecciones por Escherichia coli , Humanos , Escherichia coli , Infecciones por Escherichia coli/epidemiología , Infecciones por Escherichia coli/tratamiento farmacológico , beta-Lactamasas , Prevalencia , Análisis por Conglomerados , Infecciones Comunitarias Adquiridas/epidemiología , Infecciones Comunitarias Adquiridas/tratamiento farmacológico , Antibacterianos/uso terapéuticoRESUMEN
Novel ST398 methicillin susceptible Staphylococcus aureus (MSSA) in the United States was first observed in New York City (2004-2007); its diffusion across the country resulted in changing treatment options. Utilizing outpatient antimicrobial susceptibility data from the Veterans Health Administration from 2010 to 2019, the spatiotemporal prevalence of potential ST398 MSSA is documented.
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Digital platforms that enable and foster associations and sharing among entrepreneurs and knowledge workers have become a vital part of the new knowledge economy, yet we know little about the new form of social organization of knowledge. This paper seeks to explore and evaluate two microscopic social mechanisms, namely network effect of recruitment and cultural affinity, that may produce knowledge clustering and differentiation within these communities. To understand the relative effect of mechanisms, we develop a novel estimation procedure that matches individual users based on their historical behavioral patterns. We collected and analyzed a large-scale event dataset from a digital platform for offline in-person meetups in two major U.S. cities, New York City and San Francisco Bay Area. We found that previous methods overestimate network effect in membership adoption decisions by 176%. Our findings show that the network effect is further amplified by varied levels of cultural affinity between individuals and groups, implying a clustering effect whereby individuals tend to gravitate towards groups that are culturally proximate. Implications for understanding social differentiation and the knowledge economy are discussed.
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Nd0.5Sr0.5MnO3 nanoparticles with average sizes of 32-1000 nm in diameter were prepared by sol-gel method. The synthesized nanoparticles were characterized using X-ray diffraction, high- resolution transmission microscopy, scanning electron microscopy, and vibrating sample magnetometer. All samples have the single-phase orthorhombic structure, and the grain size increases with the increase in annealing temperature. A charge ordering (CO) transition at T(CO) and a ferromagnetic-paramagnetic transition at Tc were observed in 1000 nm nanoparticles. With the decrease in particle size, CO transition gradually shifts to lower temperature, becomes increasingly weak, and disappears for 85 nm nanoparticles. An inverse magnetocaloric effect with positive magnetic entropy change was observed around T(CO), and it decreases with the decrease in size due to the suppression of CO phase. The observed negative magnetic entropy change at Tc shows a surprising nonmonotonic behavior with the variation of particles size. All these results may give rise to a new insight into the magnetothermal behaviors in nanosized CO perovskite manganites.