Microbial Burden Assessment of Commercial Aircraft Cabin Air

摘要

The microbial burdens of 69 cabin air samples collected from commercial airliners were assessed via conven¬tional culture-dependent, and molecular-based microbial enumeration assays. Cabin air samples from each of four separate flights aboard two different carriers were collected via air-impingement. Microbial enumeration techniques targeting DNA, ATP, and endotoxin were employed to estimate total microbial burden. The total viable microbial population ranged from 0 to 3.6 x 104 cells per 100 liters of air, as assessed by the ATP-assay. When these same samples were plated on R2A minimal medium, anywhere from 2% to 80% of these viable populations were cultivable. Five of the 29 samples ex¬amined exhibited higher cultivable counts than ATP-derived viable counts, perhaps a consequence of the dormant nature (and thus lower concentration of intracel¬lular ATP) of cells inhabiting these air cabin samples. Ribosomal RNA gene sequence analysis showed these samples to consist of a moderately diverse group of bac¬teria, including human pathogens. Enumeration of ribo¬somal genes via quantitative-PCR indicated that popula¬tion densities ranged from 5 x 101 to 107 cells per 100 liters of air. Each of the aforementioned strategies for assessing overall microbial burden has its strengths and weaknesses;this publication serves as a testament to the power of their use in concert.