Sonali Bose

Analysis of home dust for Staphylococcus aureus and staphylococcal enterotoxin genes using quantitative PCR

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.

Indoor particulate matter exposure is associated with increased black carbon content in airway macrophages of former smokers with COPD

INTRODUCTION Exposure to fine particulate matter (PM2.5) is associated with worse morbidity in individuals with COPD. Inhaled PM is phagocytosed by airway macrophages (AM), and black carbon measured in AM may serve as a biomarker of air pollution exposure. As there is little data on how indoor PM exposure may influence AM black carbon content in those with respiratory disease, we investigated the association of indoor PM2.5 concentration to AM black carbon content in adults with COPD. METHODS Former smokers (>10 pack-years smoking history, quit date >1 year prior to enrollment) older than 40 years of age with moderate-severe COPD were eligible. Indoor air PM2.5 concentrations were measured over 5-7 days at baseline, 3 month, and 6 month intervals. Sputum induction was performed during clinic visits concordant with home monitoring. A total of 50 macrophages per sputum specimen were photographed and quantified using appropriate software by trained staff blinded to PM concentrations. Longitudinal analyses using generalized estimating equations were used to assess the relationship between indoor PM exposure and AM black carbon content. RESULTS Participants (n=20) were older (mean (SD) age 67 (4) years), predominantly Caucasian (85%) and male (70%), with an average smoking history of 52 pack-years and mean (SD) quit date of 13 (9) years prior to enrollment. The majority of daily time was reported to be spent indoors (>23h). Mean indoor PM2.5 concentration was 12.8 (13.5)µg/m(3). The mean area of black carbon quantified in airway macrophages was 1.2 (0.7)µm(2). In multivariate cross-sectional and longitudinal analyses, each 10µg/m(3) increase in indoor PM2.5 was significantly associated with a 0.26µm(2) and 0.19µm(2) increase in airway macrophage black carbon total area, respectively (p<0.05). CONCLUSION Higher indoor PM2.5 concentration is associated with an increase in black carbon content of AM in individuals with COPD. These data support the potential for AM black carbon content to be a useful non-invasive biomarker of exposure to indoor PM.

Association of Roadway Proximity with Indoor Air Pollution in a Peri-Urban Community in Lima, Peru.

The influence of traffic-related air pollution on indoor residential exposure is not well characterized in homes with high natural ventilation in low-income countries. Additionally, domestic allergen exposure is unknown in such populations. We conducted a pilot study of 25 homes in peri-urban Lima, Peru to estimate the effects of roadway proximity and season on residential concentrations. Indoor and outdoor concentrations of particulate matter (PM2.5), nitrogen dioxide (NO2), and black carbon (BC) were measured during two seasons, and allergens were measured in bedroom dust. Allergen levels were highest for dust mite and mouse allergens, with concentrations above clinically relevant thresholds in over a quarter and half of all homes, respectively. Mean indoor and outdoor pollutant concentrations were similar (PM2.5: 20.0 vs. 16.9 μg/m3, BC: 7.6 vs. 8.1 μg/m3, NO2: 7.3 vs. 7.5 ppb), and tended to be higher in the summer compared to the winter. Road proximity was significantly correlated with overall concentrations of outdoor PM2.5 (rs = −0.42, p = 0.01) and NO2 (rs = −0.36, p = 0.03), and outdoor BC concentrations in the winter (rs = −0.51, p = 0.03). Our results suggest that outdoor-sourced pollutants significantly influence indoor air quality in peri-urban Peruvian communities, and homes closer to roadways are particularly vulnerable.

Ultrathin bronchoscopy in the diagnosis of peripheral cavitary lung lesions.

Ultrathin (UT) bronchoscopy has emerged as a useful tool to diagnose peripheral solid lung lesions of a malignant nature. This technology is superior to standard bronchoscopic techniques, which have low yield in identifying small lesions, especially as they extend further out along the bronchial tree. UT bronchoscopy can prevent the need to pursue more invasive open lung strategies to diagnose suspicious lesions. In this report, we present 3 distinct clinical scenarios where UT bronchoscopy was successful in diagnosing benign peripheral cavitary lesions after standard techniques failed. The use of UT bronchoscopy in each case was instrumental in allowing rapid initiation of appropriate therapy without need for more invasive surgical biopsies in the setting of a benign condition.

Health Disparities Related to Environmental Air Quality

It has been more than 50 years since the Great London Smog drew the world’s attention to the poisonous health effects of air pollution. For an entire greater city area, industrial fumes permeated down to the street level, suffocating clouds replacing all breathable air. Sulfurous smoke, trapped in both outdoor spaces and within buildings, shrouded the visual world of every Londoner (Fig. 3.1). Unable to escape such a pervasive exposure, Londoners succumbed to an additional 12,000 deaths as well as numerous ER visits and hospital admissions during and in the immediate months after this environmental tragedy (Environ Health Perspect 109:389–94, 2001).

Association of traffic air pollution and rhinitis quality of life in Peruvian children with asthma

Background Air pollution exposure may contribute to rhinoconjunctivitis morbidity in children with underlying airways disease. Prior studies have not assessed rhinoconjunctivitis-related quality of life (QOL) in children with asthma chronically exposed to air pollution. Methods Children ages 9–19 years with asthma from peri-urban Peru, self-reporting rhinoconjunctivitis symptoms (n = 484), were administered the Rhinoconjunctivitis QOL Questionnaire (RQLQ) at repeated intervals over one year, with scores dichotomized into bothered (>0) and not bothered (= 0). Individual weekly exposures to particulate matter<2.5μm (PM2.5) and its black carbon (BC) component were estimated by inverse distance weighted methods. Generalized estimating equations, adjusting for covariates, estimated associations of PM2.5 and BC with QOL. Results Participants were on average 13 years old, 55% female, and majority were atopic (77%). Mean (SD) PM2.5 and BC concentrations were 21(3.2) μg/m3 and 4.4(1.5) μg/m3, respectively. In adjusted multi-pollutant models, each 10μg/m3 increase in PM2.5 was associated with increased odds of worse rhinoconjunctivitis QOL (OR;[95% CI]: 1.83;[1.33,2.52]). A 10% increase in the BC proportion was associated with higher rhinitis burden (OR;[95% CI]: 1.80;[1.22,2.66]), while increases in the non-BC component of PM did not significantly impact rhinoconjunctivitis QOL. Associations were similar regardless of atopy. Conclusion Higher PM2.5 and BC exposure is associated with worse rhinitis QOL among asthmatic children.

Rheumatoid arthritis causing diffuse alveolar haemorrhage: A novel therapeutic approach

Pulmonary vascular involvement due to rheumatoid arthritis, presenting as diffuse alveolar haemorrhage (DAH), is a rare phenomenon, especially if there are no signs of systemic vasculitides. Furthermore, how to proceed with the management of these patients is challenging, as in the case of our patient, who had recurrent DAH. We present a case of a patient with known rheumatoid arthritis who had recurrence of DAH that spanned over several years, often presenting with life-threatening respiratory failure. While her DAH presentation improved with high-dose glucocorticoids, to resolve her recurrence, we opted to initiate treatment with rituximab, with a short course of azathioprine. After the second round of rituximab, the patient continues to do well without any further DAH-related complications. We also summarise prior cases of such patients to highlight variable treatment options.

High-Frequency Chest Wall Oscillation Successful in Controlling Refractory Asthma

Introduction. High-frequency chest wall oscillation (HFCWO) has been traditionally implemented for airway secretion clearance in conditions such as cystic fibrosis (CF) and bronchiectasis. There have been few reports of its use in refractory asthma. Case report. A 36-year-old, non-smoker male presented with a lifelong history of poorly controlled asthma. Despite multiple controller medications, he reported daily chest congestion, copious phlegm, and frequent exacerbations. Imaging, blood work, and bronchoscopy ruled out atypical infections, immunodeficiency, CF, and other chronic conditions. Pulmonary function tests supported a diagnosis of asthma. Results. We initiated HFCWO therapy twice daily in addition to standard inhaled pharmacological therapy. After 2 months, the patient noted resolution of respiratory symptoms as well as improvement in lung function. He remained symptom-free at his 2-year follow-up. Conclusion. High-frequency chest oscillation may be useful in phenotypes of asthma characterized by prominent mucus hypersecretion.

Clinical characterization of children with resistant airflow obstruction, a multicenter study

ABSTRACT Objective: To characterize a cohort of children with airflow limitation resistant to bronchodilator (BD) therapy. Methods: Pulmonary function tests performed in children 6–17 years of age at 15 centers in a clinical research consortium were screened for resistant airflow limitation, defined as a post-BD FEV1 and/or an FEV1/FVC less than the lower limits of normal. Demographic and clinical data were analyzed for associations with pulmonary function. Results: 582 children were identified. Median age was 13 years (IQR: 11, 16), 60% were males; 62% were Caucasian, 28% were African-American; 19% were obese; 32% were born prematurely and 21% exposed to second hand smoke. Pulmonary diagnoses included asthma (93%), prior significant pneumonia (28%), and bronchiectasis (5%). 65% reported allergic rhinitis, and 11% chronic sinusitis. Subjects without a history of asthma had significantly lower post-BD FEV1% predicted (p = 0.008). Subjects without allergic rhinitis had lower post-BD FEV1% predicted (p = 0.003). Children with allergic rhinitis, male sex, obesity and Black race had better pulmonary function post-BD. There was lower pulmonary function in children after age 11 years without a history of allergic rhinitis, as compared to those with a history of allergic rhinitis. Conclusions: The most prevalent diagnosis in children with BD-resistant airflow limitation is asthma. Allergic rhinitis and premature birth are common co-morbidities. Children without a history of asthma, as well as those with asthma but no allergic rhinitis, had lower pulmonary function. Children with BD-resistant airflow limitation may represent a sub-group of children with persistent obstruction and high risk for life-long airway disease.