Detection ofLegionella pneumophilain bioaerosols by polymerase chain reaction

Abstract

Most studies focusing on detecting microorganisms in air by polymerase chain reaction (PCR) have used a liquid impinger to sample bioaerosols, mainly because a liquid sample is easy to be processed by PCR analysis. Nevertheless, the use of multiple-hole impactors for the analysis of bioaerosols by PCR has not been reported despite its great utility in culture analysis. In this study we have modified the impaction onto an agar surface sampling method to impaction onto a liquid medium using the MAS-100 air sampler (Merck) (single-stage multiple-hole impactor). To evaluate the recovery of airborne microorganisms of both sampling methods, a suspension containing Escherichia coli was artificially aerosolized and bioaerosols were collected onto Tergitol-7 agar and phosphate-buffered saline (PBS) with the MAS-100. A linear regression analysis of the results showed a strong positive correlation between both sampling methods (r = 0.99, slope 0.99, and y intercept 0.07). Afterwards, the method of impingement into a liquid medium was used to study airborne Legionella pneumophila by PCR. A total of 64 samples were taken at a wastewater treatment plant, a chemical plant, and an office building and analyzed by culture and PCR. Results showed that three samples were positive both by PCR and plate culture, and that nine samples negative by plate culture were positive by PCR, proving that L. pneumophila was present in bioaerosols from these three different environments. The results demonstrate the utility of this single-stage multiple-hole impactor for sampling bioaerosols, both by culture and by PCR.

Occurrence and Genetic Diversity of Uncultured Legionella spp. in Drinking Water Treated at Temperatures below 15°C

“…The primers LEG-225 and LEG-858 were used to detect Legionella by a semiquantitative dilution PCR method and by a quantitative real-time PCR method. The suitability of the primer set in detecting Legionella in environmental samples has unequivocally been demonstrated (13,38,45). The results of the present investigation shows that real-time PCR is a suitable method for selective and quantitative detection of representatives of the genus Legionella, both defined species and yet-undefined types.…”

Airborne Microorganisms Emitted from Wastewater Treatment Plant Treating Domestic Wastewater and Meat Processing Industry Wastes

“…Biological aerosols produced during wastewater treatment (discharging, mixing, aerating, and spraying of sewage) can contain various pathogenic microbes, such as viruses, fungi and bacteria, especially intestinal bacteria from the Enterobacteriaceae [6][7][8][9][10][11]. Some of these microorganisms are associated with toxic pneumonia (inhalation fever, organic dust toxic syndrome ODTS), chronic bronchitis, asthma, and other disorders [2,3,8,[11][12][13][14]. The dispersal of bioaerosols outside the facilities of WWTPs, as well as the type, amount and survival rate of airborne microorganisms depend on physicochemical and meteorological air conditions, landscape features, the time of the day, the season, and the type of treatment technology [9,[15][16][17][18][19][20][21].…”

A static water surface sampler to measure bioaerosol deposition and characterize microbial community diversity

“…Ranalli, Principi, and Sorlini (2000) and Pascual et al (2001) applied polymerase chain reaction (PCR) to identify specific bacteria in bioaerosols in the collecting media without the need of cultivation. PCR has been advocated for identification of specific organisms in bioaerosols due to its enhanced sensitivity (Alvarez, Buttner, & Stetzenbach, 1995).…”