Survival of bacteria in seawater using a diffusion chamber apparatus in situ

Abstract

A microbiological survival chamber for in situ environmental studies involving microorganisms of public health significance was developed. The autoclavable chamber was provided with a supportive base for proper flow orientation and a battery-powered stirring mechanism for continuous internal agitation. The performance of the chamber and its ancillary units was evaluated in estuarine waters by diffusion studies and survival tests with eight species of bacteria isolated from environmental sources. Polycarbonate filter membranes were found superior to cellulosic filter membranes. Continuous mixing enhanced diffusion and ensured uniform cell suspension. Salmonella enteritidis and Klebsiella pneumoniae exhibited somewhat greater viability than Escherichia coli under similar conditions. Of three indicator organisms tested, Streptococcus faecalis was the most persistent. In general, the data obtained indicate the usefulness of the chamber in measurements of microbial survival in the natural marine environment.

Survival of enteric bacteria in seawater

“…Indeed, most reports indicate enhanced stability of E. coli at lower temperatures. This was shown by Carlucci and Pramer [62] in a 48-h experiment in natural seawater (5^40³C), and by Vasoncelos and Swartz [63] in a 6-day experiment in di¡usion chambers exposed to temperatures ranging from 8.9³C to 14.5³C.…”

Survival of faecal indicator bacteria in tropical estuarine waters (Bangpakong River, Thailand)

“…Membrane diffusion chambers of different designs have been widely used in survival studies of bacteria of faecal origin (e.g. Vasconcelos and Swartz 1976;Terzieva and McFeters 1991;Mezrioui et al 1995;Wet et al 1995;Barcina et al 1997;Quang and Button 1998). The chamber model used in this study (see Materials and methods) was made of clear Plexiglas material in order to allow light and 90% u.v.…”

“…Such high naturally occurring temperatures may be deleterious for faecal bacteria in contact with saline waters. For instance, in earlier reports Vasconcelos and Swartz (1976) reported that the viability of faecal and coliform bacteria is inversely proportional to temperature, since high temperatures enhance the death of such bacteria in seawater. Several authors have mentioned nutrient starvation as a factor influencing the maintenance of allochtonous bacteria in water (Mitchell 1968;Munro et al 1987;Lim and Flint 1989;Rippey and Cabelli 1990;Bogosian et al 1996).…”

Survival of Listeria monocytogenes in sea water and effect of exposure on thermal resistance

“…Previous studies using diffusion chambers to study the survival of bacteria in the marine environment have reported that decay rates are strongly related to temperature (Vasconcelos and Swartz 1976;Anderson et al 1983;Patel and Beuchat 1995). For comparison, Lessard and Sieburth (1983) reported T 90 values at 8 and 24°C of 52·3 and 33 h for E. coli, and 95·9 and 39 h for enterococci, respectively, using selective media for enumeration.…”

“…In order to ascertain the potential impact of land run-off on shellfish populations, information is required on the survival of L. monocytogenes in sea water. Factors affecting the survival of allochthonous bacteria in sea water environments include: predation, osmotic stress, solar radiation, nutrient availability, temperature and growth phase of the bacteria of interest (Anderson et al 1983;Munro et al 1989;Gauthier et al 1992;Ahl et al 1995;Pommepuy et al 1996;Vasconcelos and Swartz 1976;Smith et al 1994). Determinations of bacterial survival are complicated by the observation that on exposure to the marine environment, many bacteria enter an altered physiological state termed viable but non-culturable (VBNC) (Elliot and Colwell 1985;Kaprelyants et al 1993;Roszak and Colwell 1987).…”