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Optimization of PMA ‐ qPCR for Staphylococcus aureus and determination of viable bacteria in indoor air
Author(s) -
Chang C.W.,
Lin M.H.
Publication year - 2018
Publication title -
indoor air
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.387
H-Index - 99
eISSN - 1600-0668
pISSN - 0905-6947
DOI - 10.1111/ina.12404
Subject(s) - propidium monoazide , staphylococcus aureus , microbiology and biotechnology , bacteria , real time polymerase chain reaction , biology , chemistry , gene , biochemistry , genetics
Staphylococcus aureus may cause infections in humans from mild skin disorders to lethal pneumonia. Rapid and accurate monitoring of viable S. aureus is essential to characterize human exposure. This study evaluated quantitative PCR ( qPCR ) with propidium monoazide ( PMA ) to quantify S. aureus . The results showed comparable S. aureus counts between exclusively live cells and mixtures of live/dead cells by qPCR with 1.5 or 2.3 μg/ mL PMA ( P >.05), illustrating the ability of PMA ‐ qPCR to detect DNA exclusively from viable cells. Moreover, qPCR with 1.5 or 2.3 μg/ mL PMA performed optimally with linearity over 10 3 ‐10 8 CFU / mL ( R 2 ≥0.9), whereas qPCR with 10, 23 or 46 μg/ mL PMA significantly underestimated viable counts. Staphylococcus aureus and total viable bacteria were further determined with PMA ‐ qPCR (1.5 μg/ mL ) from 48 samples from a public library and two university dormitories and four from outside. Viable bacteria averaged 1.9×10 4 cells/m 3 , and S. aureus were detected in 22 (42%) samples with a mean of 4.4×10 3 cells/m 3 . The number of S. aureus and viable bacteria were positively correlated (r=.61, P <.005), and percentages of S. aureus relative to viable bacteria averaged 12‐44%. The results of field samples suggest that PMA ‐ qPCR can be used to quantify viable S. aureus cells.