This large-scale study compared incubation temperatures (37°C versus 42°C) to study the detection of thermophilic
Campylobacterspecies, including Campylobacter jejuni, C. coli, and C. lari, in various surface water samples and bird fecal droppings around Hamilton Harbor, Lake Ontario. The putative culture isolates obtained from incubation temperatures of 37 and 42°C were confirmed by Campylobactergenus- and species-specific triplex PCR assays targeting the 16S rRNA gene and the 16S-23S rRNA gene internal transcribed spacer (ITS) region. A total of 759 water, wastewater, and bird fecal dropping samples were tested. Positive amplification reactions for the genus Campylobacterwere found for 454 (60%) samples incubated at 37°C, compared to 258 (34%) samples incubated at 42°C. C. jejuni(16%) and C. lari(12%) were detected significantly more frequently at the 42°C incubation temperature than at 37°C (8% and 5%, respectively). In contrast, significantly higher rates of C. coli(14%) and other Campylobacterspp. (36%) were detected at the 37°C incubation temperature than at 42°C (8% and 7%, respectively). These results were consistent across surface water, wastewater, and bird fecal dropping samples. At times, Campylobacterspp. were recovered and detected at 37°C (3% for C. jejuni, 10% for C. coli, and 3% for C. lari) when the same samples incubated at 42°C were negative. A significantly higher rate of other Campylobacterspp. was detected only at 37°C (32%) than only at 42°C (3%). These results indicate that incubation temperature can significantly influence the culturability and detection of thermophilic and other fastidious Campylobacterspp. and that a comprehensive characterization of the Campylobacterspp. in surface water, wastewaters, or bird fecal droppings will require incubation at both 37 and 42°C.