Indoor hospital air and the impact of ventilation on bioaerosols: a systematic review.

Healthcare-acquired infections (HAIs) continue to persist in hospitals, despite the use of increasingly strict infection-control precautions. Opportunistic airborne transmission of potentially pathogenic bioaerosols may be one possible reason for this persistence. Therefore, this study aimed to systematically review the concentrations and compositions of indoor bioaerosols in different areas within hospitals and the effects of different ventilation systems. Electronic databases (Medline and Web of Science) were searched to identify articles of interest. The search was restricted to articles published from 2000 to 2017 in English. Aggregate data was used to examine the differences in mean colony forming units per cubic metre (cfu/m3) between different hospital areas and ventilation types. A total of 36 journal articles met the eligibility criteria. The mean total bioaerosol concentrations in the different areas of the hospitals were highest in the inpatient facilities (77 cfu/m3, 95% confidence interval (CI): 55-108) compared with the restricted (13cfu/m3, 95% CI: 10-15) and public areas (14 cfu/m3, 95% CI: 10-19). Hospital areas with natural ventilation had the highest total bioaerosol concentrations (201 cfu/m3, 95% CI: 135-300) compared with areas using conventional mechanical ventilation systems (20 cfu/m3, 95% CI: 16-24). Hospital areas using sophisticated mechanical ventilation systems (such as increased air changes per hour, directional flow and filtration systems) had the lowest total bioaerosol concentrations (9 cfu/m3, 95% CI: 7-13). Operating sophisticated mechanical ventilation systems in hospitals contributes to improved indoor air quality within hospitals, which assists in reducing the risk of airborne transmission of HAIs.

Infection in cystic fibrosis: impact of the environment and climate.

In many countries numbers of adults with cystic fibrosis (CF) exceed that of children, with median survival predicted to surpass 50 years. Increasing longevity is, in part, due to intensive therapies including eradication of early infection and suppressive therapies and pulmonary exacerbations. Initial infections with common CF pathogens are thought to arise from the natural environment. We review the impact of climate and environment on infection in CF. Specifically, several studies indicate that higher ambient temperatures, proximity to the equator and the summer season may be linked to the increased prevalence of Pseudomonas aeruginosa in people with CF. The environment may also play an important role in the acquisition of Gram negative organisms other than P. aeruginosa. There is emerging data suggesting that climatic and environmental factors are likely to impact on the risk of infection with NTM and fungi in people which are found extensively throughout the natural environment.

Screening for activating EGFR mutations in surgically resected nonsmall cell lung cancer.

The clinical applicability of screening surgically resected nonsmall cell lung cancer (NSCLC) tumour tissue and serum for activating epidermal growth factor receptor (EGFR) mutation is unknown. Furthermore, the comparative accuracy of inexpensive EGFR mutation tests, mutant-enriched (ME)-PCR and high-resolution melt (HRM) has not been determined. Lung tumour DNA from 522 surgically resected stage I-IV NSCLC and matched serum DNA from a subset of 64 subjects was analysed for EGFR mutations in exons 19 and 21 using ME-PCR and HRM. Additionally, 97 subjects had previous EGFR DNA sequencing data available for comparison. ME-PCR and HRM detected EGFR mutations in 5% (27 out of 522) of tumour samples. Compared to DNA sequencing, ME-PCR had a sensitivity of 100% and specificity of 99%, while HRM had 100% sensitivity and specificity. Six subjects with EGFR mutation tumours had matched serum, where ME-PCR detected mutations in three samples and HRM in two samples. In the cohort of never-smoker subjects, those with EGFR mutated tumours had worse survival compared with wild-type tumours (30 versus 49 months; p=0.017). ME-PCR and HRM have similar accuracy in detecting EGFR mutations but the prognostic implications of the mutations in resected NSCLC warrants further study.