The occurrence of Campylobacter in river water and waterfowl within a watershed in southern Ontario, Canada

Abstract

Aims: Quantitative PCR and a culture method were used to investigate Campylobacter occurrence over 3 years in a watershed located in southern Ontario, Canada that is used as a source of drinking water. Methods and Results: Direct DNA extraction from river water followed by quantitative PCR analysis detected thermophilic campylobacters at low concentrations (<130 cells 100 ml−1) in 57–79% of samples taken from five locations. By comparison, a culture‐based method detected Campylobacter in 0–23% of samples. Water quality parameters such as total Escherichia coli were not highly correlated with Campylobacter levels, although higher pathogen concentrations were observed at colder water temperatures (<10°C). Strains isolated from river water were primarily nalidixic acid‐susceptible Campylobacter lari, and selected isolates were identified as Campylobacter lari ssp. concheus. Campylobacter from wild birds (seagulls, ducks and geese) were detected at a similar rate using PCR (32%) and culture‐based (29%) methods, and although Campylobacter jejuni was isolated most frequently, C. lari ssp. concheus was also detected. Conclusions: Campylobacter were frequently detected at low concentrations in the watershed. Higher prevalence rates using quantitative PCR was likely because of the formation of viable but nonculturable cells and low recovery of the culture method. In addition to animal and human waste, waterfowl can be an important contributor of Campylobacter in the environment. Significance and Impact of the Study: Results of this study show that Campylobacter in surface water can be an important vector for human disease transmission and that method selection is important in determining pathogen occurrence in a water environment.

Molecular Detection of Campylobacter spp. in California Gull (Larus californicus) Excreta

“…Most studies screening for the presence of Campylobacter in waterfowl have used cumbersome culture-based methods that are known to have low recovery yields and to potentially underestimate the number of species in a given sample (33). As a result, it is unclear what the prevalence and densities of different Campylobacter spp.…”

“…Based on previous culture estimations, Campylobacter has been estimated to range from 3.0 ϫ10 3 to 1.7 ϫ 10 7 CFU/g (wet weight) in the ring-billed gull (L. delawarensis) droppings (22), with lower estimates from herring gull and common black-headed gull (L. ridibundus) excreta (1.8 ϫ10 2 to 4.9 ϫ 10 6 CFU/g and from 7.4 ϫ 10 2 to 1.7 ϫ 10 5 CFU/g, respectively) (9). The differences between the higher estimates by qPCR assays and the lower culture-based numbers may in part reflect active but nonculturable campylobacters (25,33). The unidentified campylobacters from California gulls (which represented nearly 92% of the clones) require further examination and may represent novel species that are problematic to culture using currently available media.…”

Campylobacter in the environment: A major threat to public health

“…Similarly, it was suggested that the filtration of large volumes (e.g. 1 000 to 4 000 mL) may be appropriate for the determination of campylobacters in environmental waters [80,83]. With groundwater, the filtration of a 10 mL sample failed to recover campylobacters [84], while, successful detection of Campylobacter was achieved with the filtration of 100 to 500 mL of groundwater [17].…”

Effect of Incubation Temperature on the Detection of Thermophilic Campylobacter Species from Freshwater Beaches, Nearby Wastewater Effluents, and Bird Fecal Droppings

“…Many investigations of Campylobacter spp. in water have used a 42°C incubation temperature (9,(19)(20)(21)(22)(23)(24)(25). However, other water studies have used a 37°C incubation temperature (26)(27)(28).…”

“…These three species can commonly occur in the gastrointestinal tracts of humans and other animals, including bovines, pigs, and birds. Sea gulls and several other wild birds can be an important source of Campylobacter spp., such as C. jejuni and C. lari (3,8,9). Campylobacters from the feces of birds or domestic and wild animals, municipal sewage discharges, or agricultural runoff can contaminate water (3), and water is an established vehicle for the transmission of these species to human and domestic animals, leading to outbreaks of waterborne disease.…”