Two Outbreaks of Legionnaires Disease Associated with Outdoor Hot Tubs for Private Use - Two Cruise Ships, November 2022-July 2024.

Legionnaires disease is a serious pneumonia caused by Legionella bacteria. During November 2022-June 2024, CDC was notified of 12 cases of Legionnaires disease among travelers on two cruise ships; eight on cruise ship A and four on cruise ship B. CDC, in collaboration with the cruise lines, initiated investigations to ascertain the potential sources of on-board exposure after notification of the second potentially associated case for each ship. Epidemiologic data collected from patient interviews and environmental assessment and sampling results identified private hot tubs on selected cabin balconies as the most likely exposure source. To minimize Legionella growth, both cruise lines modified the operation and maintenance of these devices by removing the heating elements, draining water between uses, and increasing the frequency of hyperchlorination and cleaning. Hot tubs offer favorable conditions for Legionella growth and transmission when maintained and operated inadequately, regardless of location. Private hot tubs on cruise ships are not subject to the same maintenance requirements as are public hot tubs in common areas. Given the range of hot tub-type devices offered as amenities across the cruise industry, to reduce risk for Legionella growth and transmission, it is important for cruise ship water management program staff members to inventory and assess private balcony hot tubs and adapt public hot tub maintenance and operations protocols for use on private outdoor hot tubs.

Outbreak of Invasive Serratia marcescens among Persons Incarcerated in a State Prison, California, USA, March 2020-December 2022.

Serratia marcescens is an environmental gram-negative bacterium that causes invasive disease in rare cases. During 2020-2022, an outbreak of 21 invasive Serratia infections occurred in a prison in California, USA. Most (95%) patients had a history of recent injection drug use (IDU). We performed whole-genome sequencing and found isolates from 8 patients and 2 pieces of IDU equipment were closely related. We also identified social interactions among patients. We recovered S. marcescens from multiple environmental samples throughout the prison, including personal containers storing Cell Block 64 (CB64), a quaternary ammonium disinfectant solution. CB64 preparation and storage conditions were suboptimal for S. marcescens disinfection. The outbreak was likely caused by contaminated CB64 and propagated by shared IDU equipment and social connections. Ensuring appropriate preparation, storage, and availability of disinfectants and enacting interventions to counteract disease spread through IDU can reduce risks for invasive Serratia infections in California prisons.

Global VAX: A U.S. contribution to global COVID-19 vaccination efforts, 2021-2023.

In December 2021 the U.S. Government announced a new, whole-of-government $1.8 billion effort, the Initiative for Global Vaccine Access (Global VAX) in response to the global COVID-19 pandemic. Using the foundation of decades of U.S. government investments in global health and working in close partnership with local governments and key global and multilateral organizations, Global VAX enabled the rapid acceleration of the global COVID-19 vaccine rollout in selected countries, contributing to increased COVID-19 vaccine coverage in some of the world's most vulnerable communities. Through Global VAX, the U.S. Government has supported 125 countries to scale up COVID-19 vaccine delivery and administration while strengthening primary health care systems to respond to future health crises. The progress made by Global VAX has paved the way for a stronger global recovery and improved global health security.

Implementing precision oncology in Latin America to improve patient outcomes: the status quo and a call to action for key stakeholders and decision-makers.

Background: The advent of precision oncology (PO) has revolutionised diagnostic and follow up strategies and improved clinical outcomes for cancer patients. However, socio-economic inequalities in the level of implementation of PO in different countries is a prevailing issue. To improve this situation, the Latin America Patients Academy has gathered the recommendations of healthcare professionals and social civil members experienced in cancer management from Mexico, Guatemala, Costa Rica, Dominican Republic, Panama, Colombia, Chile, Ecuador, Peru and Argentina regarding the areas that need to be prioritised to improve the access to PO in Latin American (LATAM) countries. Methods: This manuscript is the culmination of a series of educational campaigns and panel discussion aimed at improving the implementations of PO in LATAM that took place from June 2021 to January 2022. The status of PO in Latin America: the level of PO implementation is generally low with some exceptions. The number of clinical trials and articles published with keywords related to PO from LATAM countries is drastically lower than in Europe and the United States. Despite sharing many complex challenges, progress is taking place in some countries in the region. Focus areas defined by the expert panel: The expert panel determined the areas of PO that should be improved by LATAM countries to improve its implementation through cancer care plans, educational programs and collaborative strategies. These initiatives should increase awareness about PO in the region and eventually improve cancer control in the region.

COVID-19 and Adolescent Outpatient Mental Health Service Utilization.

OBJECTIVE: The COVID-19 pandemic created challenges in accessing mental health (MH) services when adolescent well-being declined. Still, little is known about how the COVID-19 pandemic affected outpatient MH service utilization for adolescents. METHODS: Retrospective data were collected from electronic medical records of adolescents aged 12-17 years at Kaiser Permanente Mid-Atlantic States, an integrated health care system from January 2019 to December 2021. MH diagnoses included anxiety, mood disorder/depression, anxiety and mood disorder/depression, attention-deficit/hyperactivity disorder, or psychosis. We used interrupted time series analysis to compare MH visits and psychopharmaceutical prescribing before and after the COVID-19 onset. Analyses were stratified by demographics and visit modality. RESULTS: The study population of 8121 adolescents with MH visits resulted in a total of 61,971 (28.1%) of the 220,271 outpatient visits associated with an MH diagnosis. During 15,771 (7.2%) adolescent outpatient visits psychotropic medications were prescribed. The increasing rate of MH visits prior to COVID-19 was unaffected by COVID-19 onset; however, in-person visits declined by 230.5 visits per week (P < .001) from 274.5 visits per week coupled with a rise in virtual modalities. Rates of MH visits during the COVID-19 pandemic differed by sex, mental health diagnosis, and racial and ethnic identity. Psychopharmaceutical prescribing during MH visits declined beyond expected values by a mean of 32.8 visits per week (P < .001) at the start of the COVID-19 pandemic. CONCLUSIONS: A sustained switch to virtual visits highlights a new paradigm in care modalities for adolescents. Psychopharmaceutical prescribing declined requiring further qualitative assessments to improve the quality of access for adolescent MH.

Holistic burden of illness in patients with endogenous Cushing's syndrome: A systematic literature review.

OBJECTIVE: The objective of this systematic literature review (SLR) was to summarize the latest studies evaluating the burden of illness in endogenous Cushing's syndrome (CS), including the impact of CS on overall and domain-specific health-related quality of life (HRQoL) and the economic burden of CS to provide a holistic understanding of disease and treatment burden. METHODS: An SLR was conducted in PubMed, MEDLINE and Embase using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist to identify peer-reviewed manuscripts and conference abstracts published in English from 2015 to December 4, 2020. RESULTS: Forty-five publications were eligible for inclusion; data were extracted from 37 primary studies while 8 SLRs were included for reference only. Thirty-one studies reported HRQoL using validated patient reported outcome (PRO) measures in pre- or post-surgery, radiotherapy and pharmacotherapy patients. Overall, this SLR found that patients with CS have worse outcomes relative to healthy populations across specific dimensions, such as depression, despite an improvement in HRQoL post-treatment. These findings reveal that CS symptoms are not fully resolved by the existing care paradigm. Few studies report on the economic burden of CS and currently available data indicate a high direct healthcare system cost burden. CONCLUSIONS: Patients with CS experience a significant, complex and multifactorial HRQoL burden. Symptom-specific burden studies are sparse in the literature and the understanding of long-term CS symptomatic burden and economic burden is limited. This review intends to provide an updated reference for clinicians, payers and other stakeholders on the burden of CS as reported in published literature and to encourage further research in this area.

Serratia marcescens Outbreak at a Correctional Facility: Environmental Sampling, Laboratory Analyses and Genomic Characterization to Assess Sources and Persistence.

Serratia marcescens is an environmental bacterium and clinical pathogen that can cause an array of infections. We describe an environmental sampling and comparative genomics approach used to investigate a multi-year outbreak of S. marcescens at a correctional facility. Whole genome sequencing analysis revealed a predominant cluster of clonally related S. marcescens from nine patient cases and items associated with illicit drug use. Closely related strains found among items associated with case-patient cells and diluted Cell Block 64 (CB64), a quaternary ammonium disinfectant, and Break Out (BO), a multipurpose cleaner, highlighted their role as environmental reservoirs for S. marcescens in this outbreak. Comparative genomic analysis suggested outbreak strains were both persistent (identical strains found over long periods and in multiple locations of the correctional facility) and diverse (strains clustered with multiple global samples from NCBI database). No correlation was found between antimicrobial resistance (AMR) genes of outbreak strains; NCBI strains have more AMR genes. Principal component analysis (PCA) of virulence factors associated with persistence and infectivity indicated variation based on phylogroups, including the predominant cluster; identifiable variations among environmental versus clinical strains were not observed. Identification of multiple distinct genetic groups highlights the importance of putting epidemiological genomic studies in a proper genetic context.

Family Structure and Adolescent Mental Health Service Utilization During the COVID-19 Pandemic.

PURPOSE: This study evaluated the relationship between sociodemographic factors including family structure and mental health service (MHS) utilization before and during the COVID-19 pandemic. We also investigated the moderation effects of the COVID-19 pandemic on MHS utilization. METHODS: Our retrospective cohort study analyzed adolescents aged 12-17 years with a mental health diagnosis as identified in the electronic medical record enrolled in Kaiser Permanente Mid-Atlantic States in Maryland and Virginia, a comprehensive integrated health system. We used logistic regression models with an interaction term for the COVID-19 pandemic year to determine the relationship between family structure and adolescent MHS utilization ≥ one outpatient behavioral health visit within the measurement year, while adjusting for age, chronic medical condition (= physical illness lasting > 12 months), mental health condition, race, sex, and state of residence. RESULTS: Among 5,420 adolescents, only those in two-parent households significantly increased MHS utilization during COVID-19 compared to the prepandemic year (McNemar's χ2 = 9.24, p < .01); however, family structure was not a significant predictor. Overall, the odds of adolescents using MHS were associated with a 12% increase during COVID-19 (odds ratio 1.12, 95% confidence interval [CI]: 1.02-1.22, p < .01). Higher odds of using MHS was associated with chronic medical condition (adjusted odds ratio = 1.15; 95% CI: 1.05-1.26, p < .01) and with White adolescents compared to all racial/ethnic minorities. The odds ratio of females using MHS compared to their male counterparts increased by 63% (ratio of adjusted odds ratio = 1.63; 95% CI: 1.39-1.91, p < .01) during the COVID-19 pandemic. DISCUSSION: Individual-level demographic factors served as predictors of MHS utilization with effects moderated by COVID-19.

Evaluating the burden of endogenous Cushing's syndrome using a web-based questionnaire and validated patient-reported outcome measures.

INTRODUCTION: Endogenous Cushing's syndrome (CS) is a rare endocrine condition caused by chronic oversecretion of cortisol, resulting in a diverse constellation of symptoms. This study examined the ongoing burden of illness (BOI), from the first appearance of symptoms through treatment, which is currently not well evaluated. METHODS: A quantitative, cross-sectional, web-enabled survey including 5 validated patient reported outcomes (PRO) measures was conducted in patients with CS who had been diagnosed ≥ 6 months prior and who had received ≥ 1 treatment for their endogenous CS at the time of the survey. RESULTS: Fifty-five patients participated in this study; 85% were women. The mean age was 43.4 ± 12.3 years (± standard deviation, SD). On average, respondents reported a 10-year gap between the first occurrence of symptoms and diagnosis; 80% underwent surgical treatment for CS. Respondents experienced symptoms on 16 days in a typical month, and their health-related quality of life was moderately impacted based on the CushingQoL score. Weight gain, muscle fatigue, and weakness were the most common symptoms and 69% percent of patients reported moderate or severe fatigue using the Brief Fatigue Inventory. Following treatment, the occurrence of most symptoms declined over time, although anxiety and pain did not significantly decrease. Overall, 38% of participants reported an annual average of 25 missed workdays due to CS symptoms. CONCLUSIONS: These results demonstrate a BOI in CS despite ongoing treatment and illustrate the need for interventions to address persistent symptoms, particularly weight gain, pain, and anxiety.

CDC's COVID-19 International Vaccine Implementation and Evaluation Program and Lessons from Earlier Vaccine Introductions.

The US Centers for Disease Control and Prevention (CDC) supports international partners in introducing vaccines, including those against SARS-CoV-2 virus. CDC contributes to the development of global technical tools, guidance, and policy for COVID-19 vaccination and has established its COVID-19 International Vaccine Implementation and Evaluation (CIVIE) program. CIVIE supports ministries of health and their partner organizations in developing or strengthening their national capacities for the planning, implementation, and evaluation of COVID-19 vaccination programs. CIVIE's 7 priority areas for country-specific technical assistance are vaccine policy development, program planning, vaccine confidence and demand, data management and use, workforce development, vaccine safety, and evaluation. We discuss CDC's work on global COVID-19 vaccine implementation, including priorities, challenges, opportunities, and applicable lessons learned from prior experiences with Ebola, influenza, and meningococcal serogroup A conjugate vaccine introductions.

Estudios mamográficos en un centro metropolitano de referencia en imágenes mamarias: Chile 2008-2018 ¿Vamos por el camino correcto? / Analysis of mammograms performed in a public imaging center in Santiago, Metropolitan Region Chile 2008-2018

BACKGROUND: Mammograms are one of the most effective preventive means for the early detection of breast cancer. OBJECTIVE: To describe the features of patients and results of mammograms performed at a public breast imaging service of the Santiago Metropolitan Area. MATERIAL AND METHODS: We reviewed the reports of mammograms performed on 174,017 women and 18 men, between 2008 and 2018 in an Imaging Center. The BI-RADS classification was used in the reports. RESULTS: Forty-six percent of mammograms (75,781) were reported as BI-RADS 2. The high proportion of BI-RADS 4 reports (674 reports) was seen in patients aged 40 to 49 years, corresponding to 30% of reports in this age range. Among patients aged 50 to 59 years, there were 779 BI-RADS 4 reports (35%). BI-RADS 5 reports were more common among patients aged 50 to 59 years (50 reports, 30%) and among patients aged 70 years or older (83 reports, 28%). CONCLUSIONS: The presence of a significant number of women between 40 and 49 years of age with a BI-RADS 4 mammography result stands out; being an opportunity to develop new clinical research and public health strategies within the framework of the Universal Health Care policy for breast cancer in Chile.

Application of Arbuscular Mycorrhizal Fungi in Vineyards: Water and Biotic Stress Under a Climate Change Scenario: New Challenge for Chilean Grapevine Crop.

The crop Vitis vinifera (L.) is of great economic importance as Chile is one of the main wine-producing countries, reaching a vineyard area of 145,000 ha. This vine crop is usually very sensitive to local condition changes and agronomic practices; therefore, strategies to counteract the expected future decrease in water level for agricultural irrigation, temperature increase, extreme water stress (abiotic stress), as well as increase in pathogenic diseases (biotic stress) related to climate change will be of vital importance for this crop. Studies carried out in recent years have suggested that arbuscular mycorrhizal fungi (AMF) can provide key ecosystem services to host plants, such as water uptake implementation and enhanced absorption of nutrients such as P and N, which are key factors for improving the nutritional status of the vine. AMF use in viticulture will contribute also to sustainable agronomic management and bioprotection against pathogens. Here we will present (1) the current status of grapevines in Chile, (2) the main problems in grapevines related to water stress and associated with climate change, (3) the importance of AMF to face water stress and pathogens, and (4) the application of AMF as a biotechnological and sustainable tool in vineyards.

[Analysis of mammograms performed in a public imaging center in Santiago, Metropolitan Region Chile 2008-2018]. / Estudios mamográficos en un centro metropolitano de referencia en imágenes mamarias: Chile 2008-2018 ¿Vamos por el camino correcto?

BACKGROUND: Mammograms are one of the most effective preventive means for the early detection of breast cancer. OBJECTIVE: To describe the features of patients and results of mammograms performed at a public breast imaging service of the Santiago Metropolitan Area. MATERIAL AND METHODS: We reviewed the reports of mammograms performed on 174,017 women and 18 men, between 2008 and 2018 in an Imaging Center. The BI-RADS classification was used in the reports. RESULTS: Forty-six percent of mammograms (75,781) were reported as BI-RADS 2. The high proportion of BI-RADS 4 reports (674 reports) was seen in patients aged 40 to 49 years, corresponding to 30% of reports in this age range. Among patients aged 50 to 59 years, there were 779 BI-RADS 4 reports (35%). BI-RADS 5 reports were more common among patients aged 50 to 59 years (50 reports, 30%) and among patients aged 70 years or older (83 reports, 28%). CONCLUSIONS: The presence of a significant number of women between 40 and 49 years of age with a BI-RADS 4 mammography result stands out; being an opportunity to develop new clinical research and public health strategies within the framework of the Universal Health Care policy for breast cancer in Chile.

Arbuscular mycorrhizal fungi from acidic soils favors production of tomatoes and lycopene concentration.

BACKGROUND: Tomato is widely consumed throughout the world for its flavor and nutritional value. This functional food largely depends on the implementation of new strategies to maintain the nutraceutical value, e.g. lycopene concentration, and overcome the challenges of sustainable production and food security. The use of arbuscular mycorrhizal fungi (AMF)-based biostimulants represents one of the most promising tools for sustainable management of agricultural soils, being fundamental for organic food production, reducing fertilizers and pesticides use, and decreasing environmental damage. This study aimed at elucidating whether native arbuscular mycorrhizal fungi (AMF) could positively affect tomato yield and lycopene concentration. RESULTS: Native AMF inoculum consisted of two inoculum types: the single species Claroideoglomus claroideum, and a mix of Scutellospora calospora, Acaulospora laevis, Claroideoglomus claroideum, and Claroideoglomus etunicatum. At the end of the study up to 78% of the root system was colonized by single inoculum. Tomato diameters in single and mix mycorrhizal plants showed increases of 80% and 35% respectively. Fresh weights were 84% and 38% higher with single and mix inocula compared with the controls, respectively. The lycopene concentration in tomato fruits of plants with single and mix inoculum was higher than controls. The lycopene concentration was 124.5% and 113.9% greater in single and mix than non-inoculated plants. CONCLUSION: Tomato diameters, fresh weight and lycopene concentration was significantly higher in plants colonized by AMF compared with uninoculated plants. Results suggest that the role of single species Claroideoglomus claroideum could generate better plant performance due to its high production of extraradical mycelium. © 2021 Society of Chemical Industry.

Investigating the Feasibility of a Restaurant Delivery Service to Improve Food Security among College Students Experiencing Marginal Food Security, a Head-to-Head Trial with Grocery Store Gift Cards.

Restaurant delivery services have gained in popularity among college students; however, students participating in the Supplemental Nutrition Assistance Program (SNAP) are not allowed to redeem their benefits via restaurant delivery services. This mixed-methods head-to-head crossover trial assessed whether college students experiencing marginal food security prefer benefits via a grocery store gift card (as a proxy for traditional SNAP benefits) or via a restaurant delivery service gift card of equivalent value, and which type of benefit is more effective at improving food security status. Thirty college students experiencing marginal food security were recruited to receive $80 in cash equivalent benefits to spend over a two-month period in the form of grocery store gift cards and restaurant delivery service gift cards. Participants completed surveys and interviews to measure their food security status and share their experiences with each benefit type. After four months of benefits, 48.3% of participants improved their food security status. However, neither type of benefit was statistically better at improving food security status. Most participants preferred grocery store benefits (89.7%) over restaurant delivery service benefits (10.3%). However, more research is needed to explore whether allowing SNAP recipients to redeem their benefits with restaurant delivery services is a viable mechanism to address food challenges among college students experiencing marginal food security.

Epidemiologic Findings from Case Investigations and Contact Tracing for First 200 Cases of Coronavirus Disease, Santa Clara County, California, USA.

In January 2020, Santa Clara County, California, USA, began identifying laboratory-confirmed coronavirus disease among residents. County staff conducted case and contact investigations focused on households and collected detailed case demographic, occupation, exposure, and outcome information. We describe the first 200 test-positive cases during January 31-March 20, 2020, to inform future case and contact investigations. Probable infection sources included community transmission (104 cases), known close contact with a confirmed case-patient (66 cases), and travel (30 cases). Disease patterns across race and ethnicity, occupational, and household factors suggested multiple infection risk factors. Disproportionately high percentages of case-patients from racial and ethnic subgroups worked outside the home (Hispanic [86%] and Filipino [100%]); household transmission was more common among persons from Vietnam (53%). Even with the few initial cases, detailed case and contact investigations of household contacts capturing occupational and disaggregated race and ethnicity data helped identify at-risk groups and focused solutions for disease control.

'Spending all this time stressing and worrying and calculating': marginal food security and student life at a Diverse Urban University.

OBJECTIVE: Food security status is a continuum ranging from high to very low food security. While marginal food security falls next to high food security on the spectrum, new quantitative research indicates marginal food security status is associated with negative health outcomes and poor academic performance among college students. Qualitative research focusing on college students experiencing marginal food security has not been conducted. The current study aims to qualitatively explore experiences of college students with marginal food security and to identify themes to better understand and provide context regarding how marginal food security impacts students. DESIGN: Students were recruited for semi-structured interviews with questions designed to study the challenges associated with students' food situations. All interviews were recorded and transcribed with themes identified via an inductive approach. SETTING: A large public university on the US west coast. PARTICIPANTS: Thirty college students. RESULTS: Key themes that emerged: purchasing cheap unhealthy foods, insufficient time to prepare and eat meals on a regular basis, stress and anxiety around the inability to eat healthy food and future health issues, self-perception of health when eating poorly along with physical symptoms and low academic motivation by not fully participating in their courses due to few healthy food options or missing meals. CONCLUSION: Marginal food security can potentially diminish students' health and their capacity to learn and succeed in their coursework. The results emphasise that students experiencing marginal food security should not be grouped with students experiencing high food security.

Staphylococcus aureus skin infection recurrences among household members: an examination of host, behavioral, and pathogen-level predictors.

BACKGROUND: Many patients suffer from recurrent Staphylococcus aureus infections, but there are few data examining recurrence predictors. METHODS: We followed adults and children after treatment for S. aureus skin infections and their household contacts in Los Angeles and Chicago. We surveyed subjects for S. aureus body colonization, household fomite contamination, and behavioral and clinical factors at baseline and 3 and 6 months later. Using repeated measures modeling, we examined host, pathogen, behavioral, and clinical factors associated with recurrence. RESULTS: Among 330 index subjects, 182 (55%) were infected with an isolate of the USA300 methicillin-resistant S. aureus (MRSA) genetic background. Recurrences occurred in 39% by month 3 and 51% by month 6. Among 588 household contacts, 10% reported a skin infection by month 3 and 13% by month 6. Among index subjects, recurrence was associated with (P < .05) Los Angeles site, diabetes, recent hospitalization, recent skin infection, recent cephalexin use, and household S. aureus or MRSA fomite contamination; recurrence was inversely associated with recent contact sports participation. In the multivariate model, independent predictors of recurrence in index patients were recent hospitalization, household MRSA fomite contamination, and lack of recent contact sports participation. Among household contacts, independent predictors of subsequent skin infection were Chicago site, antibiotic use in the prior year, and skin infection in the prior 3 months. CONCLUSIONS: In our longitudinal study, patients with a S. aureus skin infection were more likely to suffer a recurrence if household fomites were MRSA contaminated. Interventions to prevent recurrence may be enhanced by decontamination of household fomites.

Ligand-controlled Co-reduction versus electroless Co-deposition: synthesis of nanodendrites with spatially defined bimetallic distributions.

The predictable synthesis of bimetallic nanostructures via co-reduction of two metal precursors is challenging due to our limited understanding of precursor ligand effects. Here, the influence of different metal-ligand environments is systematically examined in the synthesis of Pd-Pt nanostructures as a model bimetallic system. Nanodendrites with different spatially defined Pd-Pt compositions are achieved, where the local ligand environments of metal precursors dictate if temporally separated co-reduction dominates to achieve core-shell nanostructures or whether electroless co-deposition proceeds to facilitate alloyed nanostructure formation. As the properties of bimetallic nanomaterials depend on crystal ordering and composition, chemical routes to structurally defined bimetallic nanomaterials are critically needed. The approaches reported here should be applicable to other bimetallic compositions given the established reactivity of coordination complexes available for use as precursors.

Persistent environmental contamination with USA300 methicillin-resistant Staphylococcus aureus and other pathogenic strain types in households with S. aureus skin infections.

OBJECTIVE: To understand the genotypic spectrum of environmental contamination of Staphylococcus aureus in households and its persistence. DESIGN: Prospective longitudinal cohort investigation. SETTING: Index participants identified at 2 academic medical centers. PARTICIPANTS: Adults and children with S. aureus skin infections and their household contacts in Los Angeles and Chicago. METHODS: Household fomites were surveyed for contamination at baseline and 3 months. All isolates underwent genetic typing. RESULTS: We enrolled 346 households, 88% of which completed the 3-month follow-up visit. S. aureus environmental contamination was 49% at baseline and 51% at 3 months. Among households with a USA300 methicillin-resistant S. aureus (MRSA) body infection isolate, environmental contamination with an indistinguishable MRSA strain was 58% at baseline and 63% at 3 months. Baseline factors associated with environmental contamination by the index subject's infection isolate were body colonization by any household member with the index subject's infection isolate at baseline (odds ratio [OR], 10.93 [95% confidence interval (CI), 5.75-20.79]), higher housing density (OR, 1.47 [95% CI, 1.10-1.96]), and more frequent household fomite cleaning (OR, 1.62 [95% CI, 1.16-2.27]). Household environmental contamination with the index subject's infection strain at 3 months was associated with USA300 MRSA and a synergistic interaction between baseline environmental contamination and body colonization by any household member with the index subject's infection strain. CONCLUSIONS: We found that infecting S. aureus isolates frequently persisted environmentally in households 3 months after skin infection. Presence of pathogenic S. aureus strain type in the environment in a household may represent a persistent reservoir that places household members at risk of future infection.