Carriage rates of methicillin-resistant Staphylococcus aureus (MRSA) depend on anatomic location, the number of sites cultured, culture methods, and the distribution of clonotypes.

The present study was carried out to determine how active surveillance for methicillin-resistant Staphylococcus aureus (MRSA) could be improved by the use of enrichment broth and the inclusion of extra-nasal sites with nares cultures. Molecular typing was also performed to identify colonization by single or multiple strains. Surveillance cultures for MRSA were obtained from 650 patients on admission to a medical and surgical intensive care unit (ICU) in Taiwan. MRSA was detected on directly plated vs. broth-enrichment cultures in any site at 10.0% vs. 24.2%, nares 8.2% vs. 17.5%, throat 4.8% vs. 13.4%, axilla 1.2% vs. 9.1%, and perineum 1.8% vs. 9.5%, respectively. Nares cultures alone detected only 81.5% and 72.5% of all colonized patients by direct and broth-enriched cultures, respectively. The molecular typing of 68 isolates from 17 patients revealed that multisite isolates were largely indistinguishable within each patient, but four patients had multiple subtypes and another three patients had different clonotypes. The detection of MRSA carriers was considerably enhanced by broth-enrichment cultures at multiple anatomic sites and simultaneous colonization by multiple strains at different sites can occur. Epidemiological studies are needed to determine the likelihood of subsequent nosocomial infection among colonized patients detected via direct nasal versus broth-enriched cultures from multiple sites.

Predicting outcomes in HIV-infected veterans: I. Progression to AIDS.

This article and the following article (Parts I and II) report the development of two clinical staging systems for HIV-infected individuals. The objective of the research reported here (Part I) was to construct a clinical staging system to predict progression to AIDS. We analyzed data from VA Cooperative Study Number 298, a multicenter, double-blind, randomized trial that compared immediate versus deferred zidovudine therapy in 338 HIV-infected individuals who did not have AIDS at enrollment. Baseline variables were tested in univariate Cox regression for their relationship to progression to AIDS, and those that appeared predictive were examined in multivariable analysis. Based on these analyses, we constructed a new clinical staging system based on CD4+ cell count, age, hemoglobin, oral hairy leukoplakia or oral thrush, and fever. The stages of the system were significant predictors of progression to AIDS (p = 0.0001, log-rank test). In conclusion, simple, valid, clinical staging systems for HIV-infected patients can be constructed using information that is readily available in clinical practice settings. Such systems provide better prognostic distinction than CD4+ cell count alone by taking into account the known prognostic effects of other variables.

Predicting outcomes in HIV-infected veterans: II. Survival after AIDS.

This article (Part II) and the preceding article (Part I) report the development of two clinical staging systems for HIV-infected individuals. The objective of the research reported here (Part II) was to construct a clinical staging system to predict survival in patients with AIDS. We analyzed data from VA Cooperative Study Number 298, a multicenter, double-blind, randomized trial that compared immediate versus deferred zidovudine therapy in HIV-infected individuals. Baseline variables obtained at the onset of AIDS in 204 individuals were tested in univariate Cox regression for their relationship to survival, and those that appeared predictive were examined in multivariable analysis. Based on these analyses, we constructed a new AIDS Clinical Staging System. The system is based on age, CD4+ cell count, type of first AIDS-defining condition, and functional status. The stages of the system were significant predictors of survival (p = 0.0001, log-rank test). In conclusion, valid, simple clinical staging systems for patients with AIDS can be developed based on a few variables that are readily available in clinical settings.

Predicting progression to AIDS. An evaluation of two approaches.

This study evaluated the predictive validity of two clinical staging systems for HIV infection (the Rabeneck and Royce systems) using data obtained from the Department of Veterans Affairs Cooperative Study Number 298, a randomized clinical trial involving 335 symptomatic patients with CD4 counts of 200 to 500/mm3. The relation between the HIV clinical stages and progression to AIDS was examined using Kaplan-Meier estimates, and Cox models were used to determine if the stages remained predictive after controlling for CD4 count. Both systems were significant independent predictors of progression to AIDS. This work demonstrates that simple, valid staging systems for HIV infection can be developed that provide greater prognostic distinction than the CD4 count alone.

Photocatalytic degradation of PCBs in TiO2 aqueous suspensions.

A generator-column technique was used to prepare aqueous solutions of PCBs. The degradation of 2-chlorobiphenyl, Aroclor 1248, Aroclor mixture (1221, 1016, 1254, and 1260) and St. Lawrence River water by simulated sunlight or sunlight has been investigated in the presence of aqueous suspensions of TiO2. The effect of TiO2 concentration and pH on the degradation rate of PCBs have been studied. The reaction rate followed apparent first-order kinetics and increased with increasing TiO2 concentration. The half-life of the degradation process for 2-chlorobiphenyl is 20 minutes at pH 10 and 9 minutes at pH 3 in the presence of 25 mg/L of TiO2. Less chlorinated PCBs decomposed faster than higher chlorinated ones. The rate constants and half-lives of individual PCBs in the commercial PCB mixture and St. Lawrence River water were also measured.

Observed levels of elementary and middle school children's physical activity during physical education classes.

BACKGROUND: The benefits of childhood physical activity include fitness, weight control, and exercise habits that may carry over into adulthood. School physical education is the primary program responsible for training the nation's youth to be physically active and national objectives call for students to be engaged in moderate-to-vigorous physical activity at least 50% of class time. The purpose of this study was to determine through systematic observation in a regional sample of elementary and middle schools the amount of moderate-to-vigorous physical activity students obtain during physical education classes. METHODS: Twenty elementary schools and 7 middle schools were randomly sampled from the 355 elementary schools and 117 middle schools in the 20 school districts in Harris County, Texas. In addition, 9 elementary and 6 middle schools that were identified as having excellent physical education programs were sampled purposively to provide a comparison. Seven systematic observations of student's physical activity were conducted during physical education in each school. RESULTS: The average moderate-to-vigorous physical activity in the randomly selected elementary schools was 8.6%, significantly less (P < 0.05) than for the randomly selected middle schools (16.1%) or for the comparison elementary schools (20.6%) and middle schools (24.0%). CONCLUSIONS: The average amount of physical activity observed in this regional sample of schools was less than the estimated national average of 27% and far less than the national recommendation calling for a minimum of 50%.

The physical activity of fifth-grade students during physical education classes.

One hundred fifty-seven fifth-grade students in 20 of the 355 elementary schools in one Texas county were systematically observed during physical education classes. On average, the students spent 8.5% of class time in moderate to vigorous physical activity, 23.3% in minimal activity, and 68.1% in sedentary activity. None of the schools averaged 20% of class time in moderate to vigorous physical activity. The levels of physical activity observed are substantially lower than the levels called for in national health objectives.

Is childhood obesity associated with high-fat foods and low physical activity?

Childhood obesity is a major health problem with serious long-term health implications. Efforts to determine risk factors beyond genetic predisposition have been equivocal. Common notions of overeating and under-exercising as causes have not been supported by prior research. This combined prevalence and case-control study analyzed a population of children ages 8-10 to ascertain the association between exposure to high-fat foods and low levels of exercise, and obesity. The sample population of Texas school children revealed a 100% greater prevalence of childhood obesity relative to national normative standards established from 1976-1980. Neither high-fat food intake nor reported level of physical activity were independent risk factors for this condition. However, they may exert a synergistic effect when both are present in the same child. Development of more sophisticated population-based instruments will enable larger studies to investigate risk factors for childhood obesity.

Children's frequency of participation in moderate to vigorous physical activities.

Third and fourth grade boys (n = 422) and girls (n = 390) in four Texas elementary schools reported their participation in moderate to vigorous physical activities (MVPAs) over a 3-day period. Students were surveyed during class on successive days. On a subsample (n = 44), the agreement between reported and observed physical activities during physical education or recess was 86.3%. Running, walking fast, games and sports, and bicycling accounted for 70% of Total MVPAs. Of Total MVPAs reported, 47.0% for boys and 44.6% for girls were 10 min or longer in duration (LMVPA). The average number of LMVPAs per day was 1.7 for both boys and girls. Students reported significantly more occurrences of LMVPAs out of school than during school. Significant interaction between grade and gender indicated that third grade boys reported more Total MVPAs and LMVPAs than third grade girls, but fourth grade boys reported fewer Total MVPAs and LMVPAs than fourth grade girls reported fewer Total MVPAs and LMVPAs than fourth grade girls. During the 3-day reporting period, 12.3% of boys and 13.3% of girls reported no LMVPAs, and 35.6% of boys and girls reported fewer than one LMVPAs per day. While the majority of children reported obtaining at least some activity daily, a substantial proportion of children in this sample reported fewer than one LMVPA daily, indicating that many children may not be obtaining adequate amounts of physical activity.