Antimicrobial effects of automobile screen washes against Legionella pneumophila.

AIMS: Legionella pneumophila (Lp), a human pathogen, has been detected in windscreen wiper fluid reservoirs (WWFRs) where commercial screen washes (CSWs) are commonly added. Limited information is available on CSWs against planktonic Lp; however, responses of sessile Lp and planktonic Lp pre-acclimated in nutrient-limited water to CSWs remain unknown. This study thus investigates the antibacterial effects of CSWs on sessile and starved planktonic Lp, in comparison with unstarved Lp. METHODS AND RESULTS: Lp biofilms were produced on glass and WWFR materials of high-density polyethylene (HDPE) and polypropylene (PP). Planktonic Lp with and without acclimation in tap water were prepared. Log reductions in cell counts averaged 0.4-5.0 for 10 brands of CSWs against sessile Lp and 1.0-3.9 and 0.9-4.9, respectively, against starved and unstarved planktonic Lp for five CSWs. Both biofilm formation and acclimation in tap water enhanced Lp resistance to CSWs. Significantly different log-reduction values among CSW brands were observed for sessile Lp on HDPE and planktonic Lp regardless of acclimation (p < 0.05). CONCLUSIONS: Biofilm formation, starvation acclimation and CSW brand are crucial factors influencing Lp response to CSWs. SIGNIFICANCE AND IMPACT OF STUDY: This study advances the knowledge of Lp reaction in anthropogenic water systems with CSWs.

Collection efficiency of liquid-based samplers for fungi in indoor air.

This study assessed the collection efficiency (CE) of two popularly used sampling devices (BioSampler and Coriolis sampler) for fungal aerosols. Phosphate-buffered saline (PBS) supplemented with or without surfactant (Tween-20, Tween-80, or Triton X-100) and antifoam agent was prepared and used as collection liquids. The agar impactor (BioStage) was simultaneously operated with liquid-based samplers to collect fungi from seven sites located at a university building, public library, and animal farming. Fungal concentrations determined by liquid samplers were divided by those by BioStage, and the ratio values represented CE. Results indicate that the CE of BioSampler was superior to that of Coriolis (P = 0.0001) and the PBS containing surfactant collected fungi better than that without surfactant (P < 0.0001), whereas antifoam agent showed no influence (P = 0.8). Moreover, fungal concentrations determined by BioSampler with surfactant-added PBS were statistically indifferent from those by BioStage (P > 0.05) with a Spearman correlation coefficient of 0.81-0.83 (P < 0.01). In addition to sampler and collection liquid, sampling location was also identified as a significant CE factor (P = 0.006), implying potential influences by fungal genera in the studied fields. Overall, BioSampler with surfactant-supplemented PBS (eg, Triton X-100) is recommended considering the great CE and compatibility with a variety of analytical assays.