Fecal coliform bacteri

Pathak SP, Gopal K (2008) Prevalence of bacterial contamination with antibiotic-resistant and enterotoxigenic fecal coliforms in treated drinking water. J Toxicol Environ Health A 71(7) 427 33... 

At the well field adjacent to Terrieu Creek in southern France, a large proportion of fecal coliform bacteria was associated with suspended sediment, at times up to 90%. Bacterial concentrations associated with sediment in surface water and in the subsurface were very similar, indicating a close connection between the two. The association of bacteria with sediment has important implications for public health. The bacteria may be protected from predation, may be able to use the substrate as a food source, and are less susceptible to standard methods of disinfection. 

The dynamics of fecal coliforms in coastal waters depends in part on bacterial loading from streams and rivers, mass transport, and bacterial losses due to death and sedimentation. The rates at which they disappear from surface waters depend on many factors such as availability of nutrients, temperature, salinity, turbidity, degree of water mixing, solar radiation, predation, and competition [3,41,47,64,92,97,143]. However, temperature and solar radiation are considered the most important abiotic factors [39,153]. For example, Xu et al. [153] found that temperature, solar radiation, and temperature and insolation combined, explained 31%, 78%, and 87%, respectively, of coliform bacteria dieoff coefficients in a lagoon on a French Island (Noirmountier), in the Atlantic Ocean. Predation by protozoans is a major biotic factor influencing fecal coliform death rates it accounted for 47%-99% of the mortality in the Seine River, France [54,98]. 

Antibiotic resistance While genot) ic techniques identify organisms on the basis of their genetic makeup, antibiotic-resistance testing employs the fact that different kinds of antibiotics are used in humans and animals. As a result, patterns of resistance to a variety of antibiotics in the natural bacterial populations symbiotic with these organisms will differ in the environmental isolates that are human derived and those that are farm-animal or wildlife derived. In the case of antibiotic-resistance methodology, profiles of antibiotic resistance of fecal coliform bacteria from known sources are obtained and banked. The sources of new fecal coliform bacteria isolated from surface water are identified based on the degree of similarity and differences of their antibiotic-resistance characteristics to those from known sources [150]. 

Bacterial content. Coliform indicator organisms (e.g., Escherichia coh), which generally indicate contamination of well water with bacteria of soil or fecal origin, are a common laboratory measure of water quality. Fecal streptococci and fecal coliforms are more specific indicators of fecal contamination, a. Sampling... 

Fecal conform bacteria. A group of organisms common to the intestinal tracts of humans and of animals. The presence of fecal coliform bacteria in water is an indicator of pollution and of potentially dangerous bacterial contamination. 

Two studies compared the effect of rifaximin to that of neomycin and/or of rifampicin [72, 73] on the fecal flora in rats. In the first study [72] the antibiotic (1, 10, 30 and 100 mg/kg orally for 7 days) did inhibit both aerobic (especially coliforms and cocci) and anaerobic bacterial growth. Its activity was similar to that of neomycin and stronger than that of rifampicin. In the second investigation [73] the antibiotic effect on aerobic microorganisms was specifically investigated. Oral rifaximin treatment (50 mg/kg for 3 days) caused a marked reduction in the number of total aerobic bacteria and salmonellae, while neomycin led only to a decrease in salmonella counts, but did not cause statistically significant changes in the total aerobic bacterial population. 

Fecal organism inactivation was also studied in nonchlorinated secondary wastewater and raw wastewater by Kurucz et al. (1991). Fecal organisms are absorbed in a dose-dependent manner, and four to five log units of inactivation can be expected as the dose approaches 6 kGy. The total bacterial flora was inactivated at approximately the same level as the coliform for each absorbed dose, as opposed to other disinfectant methods. The fact that the total fecal organisms are inactivated at approximately the same rate indicates that high-energy electrons are indiscriminate disinfectants. 

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