A Note: Comparison of different homogenization procedures for detecting Campylobacter spp. in sewage sludge

Abstract

Crude sewage sludge contains Campylobacter spp. in a concentration of 10(1)-10(3) cfu 100 ml-1 on average. Because large variations in the number of bacteria are seen when samples are examined in parallel, we attempted to improve the detection method. Seeded sewage sludge samples were homogenized by a high-speed blender, ultrasonic bath and ultrasonic bar. Bacterial counts were determined by the MPN method in triplicate. The recovery rate was < 10%. Subsequently, sludge samples without artificial contamination were also examined. The bacterial counts varied considerably, as seen earlier. In order to enhance the detection rate of campylobacters homogenization times and frequencies were increased, samples were diluted prior to treatment and pre-enriched in non-selective broth or supplemented with detergent. None of the methods applied proved satisfactory. The bacterial counts achieved with all methods varied greatly, with minimum and maximum values lying at least two orders of magnitude apart.

Diversity of Campylobacter Isolates from Three Activated Sludge Systems

“…In addition, in agreement with data reported by most investigators, we also observed the presence of a large number of viable but not cultivable Campylobacter cells (Rollins & Colwell 1986, Carter et al 1987, Höller 1988, Humphrey 1989, Pokorny 1990, Jacob & Stelzer 1992, Höller & Schomakers-Revaka 1994.…”

“…A possible explanation for this fact is the hypothesis of environmental effects or even selective pressure on the microorganisms (Arimi et al 1988, Höller 1988, Jacob et al 1990, Jones et al 1990b. In general, survival of campylobacters in sewage may be limited by the high organic load (Höller & Schomakers-Revaka 1994).…”

“…Campylobacter is a microaerophilic microorganism which can not proliferate in the environment but can survive fairly well in aqueous environments at low temperature (Stelzer et al 1991). Studies in the United Kingdom, Germany, Italy, the Netherlands and Libya have shown that sewage is usually heavily contaminated with this pathogen; these papers have also detailed the importance of efflux from sewage plants as a major vehicle for the spread of pathogenic biotypes of C. jejuni and C. coli in the environment (Höller 1988, Betaieb & Jones 1990, Jones et al 1990a, Stelzer et al 1991, Stampi et al 1992, Höller & Schomakers-Revaka 1994, Koenraad et al 1994.…”

Distribution and Ecology of Campylobacters in Coastal Plain Streams (Georgia, United States of America)

“…The influent received by this WWTP is split evenly between human waste and poultryprocessing waste; approximately 33% of the poultry waste originates from slaughterhouses (Wilcox, personal communication). Sewage and sewage sludge have been shown to contain campylobacters at concentrations of 10 2 to 10 5 and 10 1 to 10 3 CFU 100 ml Ϫ1 , respectively (15,46). Furthermore, studies have shown that Campylobacter spp.…”

Specific Detection of Arcobacter and Campylobacter Strains in Water and Sewage by PCR and Fluorescent In Situ Hybridization

“…Previous studies have shown that sewage and sewage sludge, respectively, contain campylobacters in concentrations of 10 2 to 10 5 CFU/100 ml and 10 1 to 10 3 CFU/100 ml, respectively (12,27). Little is known about the epidemiology of Arcobacter species.…”