The effects of UVB and temperature on the survival of natural populations and pure cultures of Campylobacter jejuni, Camp. coli, Camp. lari and urease-positive thermophilic campylobacters (UPTC) in surface waters

Abstract

Aims: To determine whether diurnal and seasonal variations in campylobacters in surface waters result from the effects of temperature and u.v. radiation, and whether natural populations of Campylobacter lari and urease-positive thermophilic campylobacters (UPTC) from birds survive better in surface waters than Camp. jejuni from sewage. Methods and Results: Natural populations of Camp. lari and UPTC in sea water, and Camp. jejuni in river water, were exposed to arti®cial sunlight (equivalent to a sunny day in June). Both populations became non-culturable within 30 min, with T 90 s of 15 min and 25 min, respectively. Cultures of Camp. jejuni became non-culturable within 40 min and those of Camp. coli, Camp. lari and UPTC, within 60 min. In darkness, survival was temperature-dependent. Natural populations took 12 h at 37°C and 5 days at 4°C to become non-culturable in sea water, and slightly less in river water. Cultures of Camp. lari and UPTCs survived for signi®cantly longer than Camp. jejuni and Camp. coli. Loss of culturability for all isolates was most rapid at 37°C and slowest at 4°C. Newly isolated strains from sea water and river water behaved in an almost identical manner to NCTC strains. Conclusions: Campylobacter lari and UPTCs survive for longer in surface waters than Camp. jejuni and Camp. coli, particularly in the dark. Low Campylobacter numbers in coastal waters in the summer, especially in the afternoon, are due to the combined effects of higher temperatures and higher levels of u.v. radiation. Signi®cance and Impact of the Study: Campylobacter lari and UPTCs from birds predominate in bathing waters in Morecambe Bay because they are better able to survive; they also originate from closer to the shore than Camp. jejuni and Camp. coli in sewage ef¯uent, which survive poorly and die before the incoming tide reaches the shore. The predominance of Camp. jejuni in river water results from its dominance of the inputs and not from its ability to survive.

Temperature dependence of reportedCampylobacterinfection in England, 1989–1999

“…One such mechanism could involve survival of Campylobacter in environmental water sources. There is considerable evidence that survival of campylobacters in aquatic environments is inversely related to water temperature and that reversion to a 'viable but non-culturable ' (VNC) form can extend survival to several months [25][26][27][28]. In some cases, infectivity of these VNC strains in rats and chicks has been demonstrated [29,30].…”

Impact of Rurality, Broiler Operations, and Community Socioeconomic Factors on the Risk of Campylobacteriosis in Maryland

“…Natural populations of C. lari, have been measured in sea water (Obiri-Danso, 2001). Urease-positive thermophilic campylobacters (UPTC) have also been measured in sea water, but are believed to originate from birds (Obiri-Danso, 2001) as is often the case for coastal waters, as well as estuaries, rivers and lakes. (Hörman, 2004).…”

Campylobacter in the environment: A major threat to public health

“…A rapid decrease of campylobacters pure cultures and natural population numbers by more than one order of magnitude was observed after less than 10 min of exposure to stimulated sunlight in fresh and marine water microcosms [124]. Although light affects changes in the uptake of nutrients and inhibit the active transport and biosynthesis in Escherichia coli (E. coli) [125], the effects of light on campylobacters remains to be fully elucidated [5].…”

“…Similarly, in a study conducted by Thomas et al[120], it was found that C. jejuni survived better than C. coli and C. lari under various conditions; for example; in autoclaved de-ionised water; autoclaved environmental water; autoclaved river environmental with sediments; incubated at 5 °C , 15 °C , 25 °C and 37 °C . Conversely, Obiri-Danso et al [124] tested the survival of C. jejuni and C. coli in artificial sea water, and reported that C. jejuni and C. coli had similar survival times, and that both of these species survived less well than C. lari and UPTC. These conflicting results from different studies probably, due to variations between strains used in every study, variations of experimental systems, and growth history of the organisms [133].…”