Justin Knox

The Environment as an Unrecognized Reservoir for Community-Associated Methicillin Resistant Staphylococcus aureus USA300: A Case-Control Study

Background Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections are spreading, but the source of infections in non-epidemic settings remains poorly defined. Methods We carried out a community-based, case-control study investigating socio-demographic risk factors and infectious reservoirs associated with MRSA infections. Case patients presented with CA-MRSA infections to a New York hospital. Age-matched controls without infections were randomly selected from the hospitals Dental Clinic patient population. During a home visit, case and control subjects completed a questionnaire, nasal swabs were collected from index respondents and household members and standardized environmental surfaces were swabbed. Genotyping was performed on S. aureus isolates. Results We enrolled 95 case and 95 control subjects. Cases more frequently reported diabetes mellitus and a higher number of skin infections among household members. Among case households, 53 (56%) were environmentally contaminated with S. aureus, compared to 36 (38%) control households (p = .02). MRSA was detected on fomites in 30 (32%) case households and 5 (5%; p<.001) control households. More case patients, 20 (21%) were nasally colonized with MRSA than were control indexes, 2 (2%; p<.001). In a subgroup analysis, the clinical isolate (predominantly USA300), was more commonly detected on environmental surfaces in case households with recurrent MRSA infections (16/36, 44%) than those without (14/58, 24%, p = .04). Conclusions The higher frequency of environmental contamination of case households with S. aureus in general and MRSA in particular implicates this as a potential reservoir for recolonization and increased risk of infection. Environmental colonization may contribute to the community spread of epidemic strains such as USA300.

Social vulnerability and HIV testing among South African men who have sex with men

This study examined whether social vulnerability is associated with HIV testing among South African men who have sex with men (MSM). A community-based survey was conducted with 300 MSM in Pretoria in 2008. The sample was stratified by age, race and residential status. Social vulnerability was assessed using measures of demographic characteristics, psychosocial determinants and indicators of sexual minority stress. Being black, living in a township and lacking HIV knowledge reduced MSMs likelihood of ever having tested for HIV. Among those who had tested, lower income and not self-identifying as gay reduced mens likelihood of having tested more than once. Lower income and internalized homophobia reduced mens likelihood of having tested recently. Overall, MSM in socially vulnerable positions were less likely to get tested for HIV. Efforts to mitigate the effects of social vulnerability on HIV testing practices are needed in order to encourage regular HIV testing among South African MSM.

Staphylococcus aureus infections: transmission within households and the community

Staphylococcus aureus, both methicillin susceptible and resistant, are now major community-based pathogens worldwide. The basis for this is multifactorial and includes the emergence of epidemic clones with enhanced virulence, antibiotic resistance, colonization potential, or transmissibility. Household reservoirs of these unique strains are crucial to their success as community-based pathogens. Staphylococci become resident in households, either as colonizers or environmental contaminants, increasing the risk for recurrent infections. Interactions of household members with others in different households or at community sites, including schools and daycare facilities, have a critical role in the ability of these strains to become endemic. Colonization density at these sites appears to have an important role in facilitating transmission. The integration of research tools, including whole-genome sequencing (WGS), mathematical modeling, and social network analysis, has provided additional insight into the transmission dynamics of these strains. Thus far, interventions designed to reduce recurrent infections among household members have had limited success, likely due to the multiplicity of potential sources for recolonization. The development of better strategies to reduce the number of household-based infections will depend on greater insight into the different factors that contribute to the success of these uniquely successful epidemic clones of S. aureus.

Environmental Contamination as a Risk Factor for Intra-Household Staphylococcus aureus Transmission

Background The household is a recognized community reservoir for Staphylococcus aureus. This study investigated potential risk factors for intra-household S. aureus transmission, including the contribution of environmental contamination. Methods We investigated intra-household S. aureus transmission using a sample of multiple member households from a community-based case-control study examining risk factors for CA-MRSA infection conducted in Northern Manhattan. During a home visit, index subjects completed a questionnaire. All consenting household members were swabbed, as were standardized environmental household items. Swabs were cultured for S. aureus. Positive isolates underwent further molecular characterization. Intra-household transmission was defined as having identical strains among two or more household members. Multiple logistic regression was used to identify independent risk factors for transmission. Results We enrolled 291 households: 146 index cases, 145 index controls and 687 of their household contacts. The majority of indexes were Hispanic (85%), low income (74%), and female (67%), with a mean age of 31 (range 1–79). The average size of case and control households was 4 people. S. aureus colonized individuals in 62% of households and contaminated the environment in 54% of households. USA300 was the predominant clinical infection, colonizing and environmental strain. Eighty-one households had evidence of intra-household transmission: 55 (38%) case and 26 (18%) control households (P<.01). Environmental contamination with a colonizing or clinical infection strain (aOR: 5.4 [2.9–10.3] P<.01) and the presence of a child under 5 (aOR: 2.3 [1.2–4.5] P = .02) were independently associated with transmission. In separate multivariable models, environmental contamination was associated with transmission among case (aOR 3.3, p<.01) and control households (aOR 27.2, p<.01). Conclusions Environmental contamination with a colonizing or clinical infection strain was significantly and independently associated with transmission in a large community-based sample. Environmental contamination should be considered when treating S. aureus infections, particularly among households with multiple infected members.

The fallacy of intimacy: sexual risk behaviour and beliefs about trust and condom use among men who have sex with men in South Africa.

The objective of this study is to assess (1) whether beliefs about trust and condom use affect sexual risk behaviour, and (2) if beliefs about trust and condom use impact sexual risk behaviour directly or if this relationship is mediated by other determinants. The Information-Motivation-Behavioural Skills model was used as a framework for the mediation analysis. A diverse cohort of three hundred 18–40 year old men who have sex with men (MSM) residing in Pretoria, South Africa, were recruited and surveyed for this project. Findings indicate that men who report a high frequency of past unprotected anal intercourse are more likely to believe that it is not necessary to use condoms with a trusted or steady partner regardless of their current partnership status. This fallacy of intimacy appears to affect sexual risk behaviour through intentions and attitudes regarding safer sex practices. Based on these findings, we recommend that more attention be given in gaining a better understanding of how beliefs about trust and condom use are formed and how they can be changed among MSM in South Africa.

Same-Sex and Different-Sex Parent Households and Child Health Outcomes: Findings from the National Survey of Children's Health.

Objective: Using the 2011–2012 National Survey of Childrens Health data set, we compared spouse/partner relationships and parent-child relationships (family relationships), parenting stress, and childrens general health, emotional difficulties, coping behavior, and learning behavior (child outcomes) in households of same-sex (female) versus different-sex continuously coupled parents with biological offspring. We assessed whether associations among family relationships, parenting stress, and child outcomes were different in the 2 household types. Methods: Parental and child characteristics were matched for 95 female same-sex parent and 95 different-sex parent households with children 6 to 17 years old. One parent per household was interviewed by telephone. Multivariate analyses of variance and multiple linear regressions were conducted. Results: No differences were observed between household types on family relationships or any child outcomes. Same-sex parent households scored higher on parenting stress (95% confidence interval = 2.03–2.30) than different-sex parent households (95% confidence interval = 1.76–2.03), p = .006. No significant interactions between household type and family relationships or household type and parenting stress were found for any child outcomes. Conclusion: Children with female same-sex parents and different-sex parents demonstrated no differences in outcomes, despite female same-sex parents reporting more parenting stress. Future studies may reveal the sources of this parenting stress.

HIV Testing Practices of South African Township MSM in the Era of Expanded Access to ART

AbstractWhile men who have sex with men (MSM) in Africa are at high risk for HIV infection, few of those already infected know their status. Effectively promoting frequent HIV testing—of increasing importance with the expanding accessibility of antiretroviral treatment—requires an understanding of the testing practices in this population. To understand men’s HIV testing practices, including their behavior, experiences, and perceptions, we conducted in-depth interviews with 81 black South African MSM (ages 20–39), purposively recruited from four townships. Many men in the sample had tested for HIV. While ever having tested seemed to facilitate repeat testing, men still expressed a high level of discomfort with testing. It was common to test after having engaged in risky behavior, thus increasing anxiety about testing that was already present. Fear that they might test HIV positive caused some men to avoid testing until they were clearly sick, and others to avoid testing completely. HIV testing may increase in this population if it becomes a routine practice, instead of being driven by anxiety-inducing incidents. Mobilization through social support might facilitate frequent testing while education about current treatment options is needed. ResumenAunque la población de hombres que tienen sexo con hombres (HSH) en África corre un alto riesgo de infección del VIH, pocos de ellos que ya están infectados con el virus conocen su diagnóstico. Promover exitosamente el uso de la prueba del VIH frecuente y regularmente—una práctica de creciente importancia con la mayor disponibilidad de los tratamientos antiretrovirales—requiere un entendimiento de las prácticas de esta población en relación a la prueba. Para entender las prácticas de la prueba del VIH en hombres, incluyendo sus comportamientos, experiencias y percepciones, llevamos a cabo entrevistas en profundidad con 81 HSH negros sudafricanos de 20 a 39 años de edad, intencionalmente reclutados de cuatro localidades (townships). Al parecer, muchos de los hombres se habían hecho la prueba. Aunque el hecho de haberse hecho la prueba parece facilitar la repetición de esta, los hombres expresaron altos niveles de incomodidad. Fue común hacerse la prueba después de haber tenido conductas de riesgo, así aumentando la ansiedad sobre la prueba ya existente. El temor de tener un resultado de VIH-positivo causó que algunos hombres postergaran la prueba hasta que estuvieran claramente enfermos y a otros que evitaran someterse a ella por completo. Convertir a la prueba de VIH en una práctica rutinaria, en vez de un acto estimulado por incidentes coyunturales y altamente preocupantes, probablemente incrementará el uso de la prueba entre esta población. Una movilización a través del apoyo social podría facilitar el uso frecuente de la prueba.

Community-associated methicillin-resistant Staphylococcus aureus transmission in households of infected cases: a pooled analysis of primary data from three studies across international settings.

Diverse strain types of methicillin-resistant Staphylococcus aureus (MRSA) cause infections in community settings worldwide. To examine heterogeneity of spread within households and to identify common risk factors for household transmission across settings, primary data from studies conducted in New York (USA), Breda (The Netherlands), and Melbourne (Australia) were pooled. Following MRSA infection of the index patient, household members completed questionnaires and provided nasal swabs. Swabs positive for S. aureus were genotyped by spa sequencing. Poisson regression with robust error variance was used to estimate prevalence odds ratios for transmission of the clinical isolate to non-index household members. Great diversity of strain types existed across studies. Despite differences between studies, the index patient being colonized with the clinical isolate at the home visit (P < 0·01) and the percent of household members aged <18 years (P < 0·01) were independently associated with transmission. Targeted decolonization strategies could be used across geographical settings to limit household MRSA transmission.

Association of Environmental Contamination in the Home With the Risk for Recurrent Community-Associated, Methicillin-Resistant Staphylococcus aureus Infection

IMPORTANCE The role of environmental contamination in recurrent Staphylococcus aureus infections within households and its potential effect on intervention strategies has been debated recently. OBJECTIVE To assess whether household environmental contamination increases the risk for recurrent infection among individuals with a community-associated methicillin-resistant S aureus (MRSA) infection. DESIGN, SETTING, AND PARTICIPANTS This cohort study was conducted from November 1, 2011, to June 30, 2014, in the Columbia University Medical Center catchment area. All patients within 72 hours of presentation with skin or soft-tissue infections and blood, urine, or sputum cultures positive for MRSA were identified. Two hundred sixty-two patients met study inclusion criteria; 83 of these (31.7%) agreed to participate (index patients) with 214 household members. Participants were followed up for 6 months, and 62 of the 83 households (74.7%) completed follow-up. Participants and researchers were blinded to exposure status throughout the study. Follow-up was completed on June 30, 2014, and data were assessed from July 1, 2014, to February 19, 2016. EXPOSURE Concordant environmental contamination, defined as having an isolate with the identical staphylococcal protein A and staphylococcal chromosomal cassette mec type or antibiogram type as the index patients clinical isolate, present on 1 or more environmental surfaces at the time of a home visit to the index patient after infection. MAIN OUTCOMES AND MEASURES Index recurrent infection, defined as any self-reported infection among the index patients during follow-up. RESULTS One patient did not complete any follow-up. Of the remaining 82 index patients, 53 (64.6%) were female and 59 (72.0%) were Hispanic. The mean age was 30 (SD, 20; range, 1-79) years. Forty-nine of 61 MRSA infections where the clinical isolate could be obtained (80.3%) were due to the epidemic strain USA300. Among the 82 households in which a patient had an index MRSA infection, the clinical isolate was present in the environment in 20 (24.4%) and not found in 62 (75.6%). Thirty-five patients (42.7%) reported a recurrent infection during follow-up, of whom 15 (42.9%) required hospitalization. Thirteen recurrent infections were from the 20 households (65.0%) with and 22 were from the 62 households (35.5%) without environmental contamination (P = .04). Environmental contamination increased the rate of index recurrent infection (incident rate ratio, 2.05; 95% CI, 1.03-4.10; P = .04). CONCLUSIONS AND RELEVANCE Household environmental contamination was associated with an increased rate of recurrent infection. Environmental decontamination should be considered as a strategy to prevent future MRSA infections, particularly among households where an infection has occurred.

Age and sexual risk among Black men who have sex with men in South Africa: the mediating role of attitudes toward condoms.

The results of research linking age and sexual risk among men who have sex with men have been inconsistent. This study assessed the relationship between age and sexual risk among 193 Black men who have sex with men in Pretoria. Older men who have sex with men reported engaging in more frequent unprotected insertive anal intercourse. We examined whether components of Information–Motivation–Behavioral Skills model mediated this relationship. Results showed that (1) older age predicts less positive attitudes toward condoms, (2) less positive attitudes predict more frequent unprotected insertive anal intercourse, and (3) attitudes mediate the relationship between age and frequency of unprotected insertive anal intercourse. We consider two possible explanations for these findings: a developmental trajectory and a cohort effect.