Sunlight inactivation of Campylobacter jejuni and Salmonella enterica, compared with Escherichia coli, in seawater and river water

Abstract

The inactivation of Campylobacter jejuni and Salmonella enterica, compared with Escherichia coli, was determined in 100 l chambers of seawater and river water located at an outdoor site. The chambers (paired with dark controls) were seeded with waste stabilization pond effluent and laboratory-cultured pathogens, and exposed to sunlight in summer and winter experiments. All sunlight inactivation (k S ) rates, as a function of cumulative global solar radiation (insolation), were far higher than the corresponding dark (k D ) rates, with a ranking (and average k S rates for seawater and river water, respectively) of: C. jejuni (3.23; 2.34) . S. enterica (0.51; 0.37) . E. coli (0.34; 0.26). All the T 90 (time to 90% inactivation) values were higher in winter than in summer, but there was far greater similarity between the summer and winter S 90 (insolation needed for 90% inactivation) values. The rapid inactivation of C. jejuni was attributed to a high susceptibility to photooxidative damage. The results suggest that, in sunlight-exposed waters, E. coli will be a more conservative indicator for C. jejuni than for S. enterica, and C. jejuni transmission as a pathogenic agent is less likely than for S. enterica.

Salmonellae in the Environment

“…The lethat effect of sunlight is probably aggravated by the high salinity of seawater, therefore, the U. V. component of sunlight and the high salinity may act synergistically in causing decrease in the numbers of culturable S. Typhimurium (Davies & Evison, 1991). The same conclusion was drawn with regard to the combined effect of sunlight and salinity on the survival of Salmonella enterica in seeded in situ seawater chambers (Sinton et al, 2007). In freshwaters however, the survival of salmonellae may be extended for periods longer than in seawater, as a result of the presence of humic materials that may absrobe U. V. radiation, therefore, protecting the cells from possible damage to the DNA by radiation (Davies & Evison, 1991).…”

“…In freshwaters however, the survival of salmonellae may be extended for periods longer than in seawater, as a result of the presence of humic materials that may absrobe U. V. radiation, therefore, protecting the cells from possible damage to the DNA by radiation (Davies & Evison, 1991). Generally, natural light affects the uptake of nutrients and inhibits active transport and biosynthesis in Escherichia coli (Barcina et al, 1990); its effect on salmonellae serovars may require further investigation (Sinton et al, 2007).…”

Oxidation pond for municipal wastewater treatment

“…In addition, Reinoso and Becares (2008) observe that the prevalence of sunlight reduces Cryptosporidium parvum by 40 %. Oxidation ponds can also reduce other pathogens such as Campylobacter jejuni, Salmonella enterica, and E. coli (Sinton et al 2007), reducing salmonella in particular by 96.4 % (Gopo et al 1997). Oxidation ponds can also remove viruses (NoV), 47 % geogroup I (GI) and 67 % geogroup II (GII) (Da Silva et al 2008).…”

The Occurrence of Salmonella in Various Marine Environments in Turkey

“…In this study, seawater temperature was the only variable showing a linear positive effect on the presence of Salmonella in the sea, while the other parameters showed more complex nonlinear effects in the studied areas. There are many factors such as temperature, salinity, sunlight, grazing by heterotrophic microorganisms affecting the survival of enteric bacteria in marine areas (Sinton et al 2007: Harm, 1980, Gameson & Gould 1985, Jagger 1985, Rozen and Belkin 2001, Sinton 2005 Temperature also seemed to affect efficiently the abundance of indicator bacteria and Salmonella spp. in the study areas.…”