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OBJECTIVE: In this study we evaluated the levels of Staphylococcus aureus and antibiotic-resistant S. aureus in colony-forming units (CFU) per cubic meter of air. DESIGN: We used Andersen two-stage samplers to collect bioaerosol samples from 24 houses in El Paso, Texas, using tryptic soy agar as the collection media, followed by the replicate plate method on Chapman Stone selective medium to isolate S. aureus. The Kirby-Bauer disk diffusion method was used to determine antibiotic resistance to ampicillin, penicillin, and cefaclor, which represent two distinct classes of antibiotics. RESULTS: The average recovered concentration of respirable heterotrophic organisms found outside each home was 345.38 CFU/m³, with an average of 12.63 CFU/m³ for S. aureus. The average recovered concentration of respirable heterotrophic organisms found inside each home was 460.23 CFU/m³, with an average of 15.39 CFU/m³ for S. aureus. The respirable S. aureus recovered from inside each home had an average resistance of 54.59% to ampicillin and 60.46%. to penicillin. Presence of cefaclor-resistant and of multidrug-resistant S. aureus was the same, averaging 13.20% per house. The respirable S. aureus recovered from outside each home had an average resistance of 34.42% to ampicillin and 41.81% to penicillin. Presence of cefaclor-resistant and of multidrug-resistant S. aureus was the same, averaging 13.96% per house. CONCLUSIONS: This study indicates that antibiotic-resistant bioaerosols are commonly found within residential homes. Our results also suggest that resistant strains of airborne culturable S. aureus are present in higher concentrations inside the study homes than outside the homes. [ABSTRACT FROM AUTHOR]

The study discussed here evaluated the presence of self-reported respiratory symptoms and their association with indoor bioaerosol concentrations over a year-long study in the El Paso, Texas, region. The authors collected air samples from homes to assess seasonal differences in bacterial and fungal bioaerosol concentrations. They distributed a health questionnaire to the participating homeowner during each seasonal air sampling. The authors used this questionnaire to assess whether the homeowners were suffering from specific symptoms prior to each sampling. Descriptive statistics and logistic regressions were conducted to model the relationship among "high" reporters of symptoms, bioaerosols, and environmental factors. The authors collected evidence to support an association between indoor respirable bacterial concentrations and homeowners that reported at least eight respiratory symptoms (odds ratio [OR] = 1.10, p = .045). Smoking status, indoor humidity, and season also displayed associations with homeowners that reported at least eight respiratory symptoms (current smokers OR = 3.3, p = .042; indoor humidity OR = 1.5, p = .030; spring season OR = 7.2, p = .001; fall season OR = 3.4, p = .008). [ABSTRACT FROM AUTHOR]

The authors conducted a study in the El Paso, Texas, region to assess the seasonal bioaerosol concentrations in a convenience sample of one-story residences. The authors sampled the same houses for each season over the course of a year (March 2005 to February 2006) to determine bacterial and fungal concentrations. They used a two-stage ambient culturable sampler system to collect the bioaerosol samples. They took indoor and outdoor bioaerosol samples and studied meteorological conditions for each house at each season. The study found that most of the measured bioaerosol concentrations differed statistically by season (p < .05). The greatest concentrations throughout the year were found to occur in fine-sized indoor bacteria during the winter. Meteorological conditions were found not to significantly influence bioaerosol concentrations throughout the year. [ABSTRACT FROM AUTHOR]

This study was undertaken to determine the normal indoor and outdoor airborne culturable fungal constituents and concentrations of an arid environment. Air samples were taken with two-stage, ambient, culturable sampler systems and analyzed for nine specific fungal genera from 50 homes as a repeated measure during each season of the year. These homes had no previous histories of indoor air quality issues. This study detected seasonal differences for the arid environment between different culturable fungal concentrations across the two size ranges. The highest concentrations were during fall, in the outdoor fine-size range. The lowest concentrations were the indoor coarse concentrations in the spring. From this study it can be concluded that Cladosporium spp. had the highest concentrations during fall in an arid environment. The overall findings suggest that Cladosporium had concentrations greater than the other genera evaluated, specifically, the fall outdoor fine concentrations. Seasonality was found to be a key factor in determining the variability of fungal constituents and concentrations within the arid indoor and outdoor environments. The fine-size range was 12 times and 6 times greater than the coarse-size range for indoor and outdoor samples, respectively, which accounted for the majority of fungal organisms. In addition, the results from this study in an arid climate differ from those conducted in a moister climate.