The authors have demonstrated elevated ozone concentrations in passenger cabins. They give several practical recommendations to help solve the problem.

Occupational exposure to swine has been associated with increased Staphylococcus aureus carriage, including antimicrobial-resistant strains, and increased risk of infections. To characterize animal and environmental routes of worker exposure, we optimized methods to identify S. aureus on operations that raise swine in confinement with antibiotics (industrial hog operation: IHO) versus on pasture without antibiotics (antibiotic-free hog operation: AFHO). We associated findings from tested swine and environmental samples with those from personal inhalable air samplers on worker surrogates at one IHO and three AFHOs in North Carolina using a new One Health approach. We determined swine S. aureus carriage status by collecting swab samples from multiple anatomical sites, and we determined environmental positivity for airborne bioaerosols with inhalable and impinger samplers and a single-stage impactor (ambient air) cross-sectionally. All samples were analyzed for S. aureus, and isolates were tested for antimicrobial susceptibility, absence of scn (livestock marker), and spa type. Seventeen of twenty (85%) swine sampled at the one IHO carried S. aureus at >1 anatomical sites compared to none of 30 (0%) swine sampled at the three AFHOs. All S. aureus isolates recovered from IHO swine and air samples were scn negative and spa type t337; almost all isolates (62/63) were multidrug resistant. S. aureus was recovered from eight of 14 (67%) ambient air and two (100%) worker surrogate personal air samples at the one IHO, whereas no S. aureus isolates were recovered from 19 ambient and six personal air samples at the three AFHOs. Personal worker surrogate inhalable sample findings were consistent with both swine and ambient air data, indicating the potential for workplace exposure. IHO swine and the one IHO environment could be a source of potential pathogen exposure to workers, as supported by the detection of multidrug-resistant S. aureus (MDRSA) with livestock-associated spa type t337 among swine, worker surrogate personal air samplers and environmental air samples at the one IHO but none of the three AFHOs sampled in this study. Concurrent sampling of swine, personal swine worker surrogate air, and ambient airborne dust demonstrated that IHO workers may be exposed through both direct (animal contact) and indirect (airborne) routes of transmission. Investigation of the effectiveness of contact and respiratory protections is warranted to prevent IHO worker exposure to multidrug-resistant livestock-associated S. aureus and other pathogens.

Patients with community-onset methicillin-resistant (CO-MRSA) infections contribute to MRSA contamination of the home environment, and may be re-exposed to MRSA strains from this reservoir. This study evaluates One Health risk factors that focus on the relationship between humans, animals and the environment for increased prevalence of multiple antimicrobial resistant MRSA in the home environment. During a trial of patients with CO-MRSA infection, MRSA was isolated from the household environment at baseline and three months later, following randomization of patients and household members to mupirocin-based decolonization therapy or education control. Up to two environmental MRSA isolates per visit were tested. MRSA isolates were identified in 68% (65/95) of homes at baseline (=104 isolates) and 51% (33/65) of homes three months later (=56 isolates). Rates of MDR were 61% at baseline and 55% at the three-month visit. At baseline, 100% (14/14) of MRSA isolates from rural homes were MDR. While antimicrobial use in humans or pets was associated with an increased risk for the isolation of MDR MRSA from the environment, clindamycin use was not associated risk for isolation of MDR MRSA. Two (5%) of 39 homes that were randomized to mupirocin treatment, but none of the control families, had incident low-level mupirocin resistant MRSA isolated at three months. Among patients recently treated for a CO-MRSA infection, MRSA and MDR MRSA were common contaminants in the home environment. This study contributes to evidence that occupant use of antimicrobial drugs--except clindamycin--is associated with MDR MRSA in the home environmental reservoir. MRSA is a common bacterial agent implicated in skin and soft tissue infections (SSTIs) in both community and healthcare settings. Patients with CO-MRSA infections contribute to MRSA contamination and may be re-exposed to MRSA strains from these reservoirs. People interact with natural and built environments, therefore understanding the relationships between humans and animals as well as characteristics of environmental reservoirs is important to advance strategies to combat antimicrobial resistance. Household interactions may influence the frequency and duration of exposure, which in turn may impact the duration of MRSA colonization or probability for recurrent colonization and infection. Therefore, MRSA contamination of the home environment may contribute to human and animal recolonization and decolonization treatment failure. The aim of this study was to evaluate One Health risk factors that may be amenable to intervention and may influence the recovery of MDR and mupR resistance in CO-MRSA isolates.

Background The bacterium Staphylococcus aureus (SA) is known to induce allergic inflammatory responses, including through secreted staphylococcal enterotoxin (SE) superantigens. To quantify indoor environmental exposures to these potential allergens, which may be associated with worse asthma, we developed a method for the assessment of S. aureus and SE in home dust and applied it to a study of homes of inner-city adults with asthma. Methods We conducted laboratory experiments to optimize sample processing and real-time PCR methods for detection and quantification of SA (femB) and SEA-D, based on published primers. We applied this method to dust and dust extract from 24 homes. We compared results from real-time PCR to culture-based results from the same homes. Results The bacteremia DNA isolation method provided higher DNA yield than alternative kits. Culture-based results from homes demonstrated 12 of 24 (50%) bedrooms were contaminated with S. aureus, only one of which carried a SE gene (SEC). In contrast, femB was detected in 23 of 24 (96%) bedrooms with a median of 1.1 × 106 gene copies detected per gram of raw dust. Prevalence and median copy number (shown in parenthesis) of SE gene detection in bedroom dust was: SEA 25% (1.4 × 102); SEB 63% (1.4 × 103); SEC 63% (1.1 × 103); SED 21% (1.3 × 102). Conclusions Our culture-independent method to detect S. aureus and SE in home dust was more sensitive than our culture-based method. Prevalence of household exposure to S. aureus and SE allergens may be high among adults with asthma.

Summary This is the first study to find that environmental Staphylococcus aureus and staphylococcal enterotoxins in a national population of inner-city adolescents with asthma are common and have the potential to drive asthma symptoms.