Prevalence and genetic characterization of Pseudomonas aeruginosa in drinking water in Guangdong Province of China

• The 25%, 32.3% and 4.6% of source water, carboned water and finished water respectively were positive for Pseudomonas aeruginosa.
• All P. aeruginosa isolates were grouped into five clusters showing 31 types by ERIC-PCR fingerprinting.
• All P. aeruginosa strains were grouped with seven clusters and thirty-seven RADP types.
• Five virulence genes (ExoU, EcfX, ExoS, phzM, toxA, and lasB) profiles were observed among 43 of P. aeruginosa.

Pseudomonas aeruginosa is an important opportunistic pathogen in drinking water and monitoring P. aeruginosa strains is of importance for microbial safety. Here, prevalence of P. aeruginosa in drinking water samples (n = 206) from Guangdong of China were surveyed, and then P. aeruginosa were further characterized by DNA-based fingerprinting and detection of virulent factors. Result indicated that 25% of source water, 32.3% of carboned water, and 4.6% of finished water were positive for P. aeruginosa. Among 43 of P. aeruginosa isolates, ExoU, EcfX, ExoS, phzM, toxA, and lasB genes were present in 20.9%, 100%, 70%, 97.7%, 93% and 100% of isolates respectively. In addition, based on 90% similarity, P. aeruginosa were grouped into thirty-one ERIC types with discriminatory ability (D) of 97.34% and thirty-seven RAPD types using primer 208 or 272 independently with D of 99.22%. Some stains including PA4 and PA5 from 5# location; PA38, PA39 and PA40 from 42#; PA18 and PA19 from 7# showed the same types using both ERIC and RAPD typing methods. This study contributes to the valuable information about prevalence of P. aeruginosa in drinking water of Guangdong, and their characterization is helpful to trace the possible origins of P. aeruginosa through the drinking water chain.