The enumeration of Bacteroides fragilis group organisms from sewage and natural waters

Abstract

A membrane filtration technique has been developed for the enumeration of Bacteroides fragilis group (BFG) organisms from sewage and natural waters. The method uses the agar medium of Wilkins and Chalgren supplemented with gentamicin, penicillin, aesculin and ferric ammonium citrate. Membrane filters with 0.22 micron pores were significantly more efficient than those with 0.45 micron pores in the isolation of BFG. A preliminary incubation period of 4 h at 30 degrees C prior to 44 h at 37 degrees C yielded significantly higher numbers of BFG than direct incubation at 37 degrees C for 48 h.

Distinguishing human from animal faecal contamination in water: A review

“…In clinical microbiology, blood agar supplemented with gentamicin, neomycin, or kanamycin (to suppress growth of facultative anaerobes) is frequently used. For sewage contaminated samples, penicillin-G may be added to inhibit clostridia (Sutter & Finegold 1971), although Allsop & Stickler (1984) found some constituents of supplemented blood agar to be unstable. They developed WCPG medium, based on the medium of Wilkins & Chalgren (1976), for use with membrane filtration.…”

“…in numbers c. 100 times greater than those of E. coli in human faeces lead Post et al (1967), and later Allsop & Stickler (1985), to suggest that these anaerobes might serve as alternative faecal indicators to E. coli. Allsop & Stickler (1984) reported "presumptive BFG" counts from human faeces as ranging from 9.7 x 10 8 to 2.8 X 10 9 /g. In contrast, Bacteroides spp.…”

Unsuitability of Quantitative Bacteroidales 16S rRNA Gene Assays for Discerning Fecal Contamination of Drinking Water

“…The numbers of Bacteroides spp. in the intestinal tract of humans and animals are 10 to 100 times higher than the numbers of E. coli or intestinal enterococci (1,2,12,26). However, the use of Bacteroides spp.…”

“…However, the use of Bacteroides spp. as indicator organisms was hampered by the complex cultivation conditions required (1,2). The introduction of molecular methods made it possible to detect bacterial species that belong to the order Bacteroidales, an order that includes the genus Bacteroides, without cultivation.…”

Quantitative PCR Method for Sensitive Detection of Ruminant Fecal Pollution in Freshwater and Evaluation of This Method in Alpine Karstic Regions

“…Microbial source tracking (MST) serves this purpose and makes it possible to pinpoint pollution sources. Anaerobic bacteria of the phylum Bacteroidetes are highly abundant in feces (32), have been proposed as fecal indicator organisms (2,3,13), and exhibit host adaptation on the genetic level (10,16). More recently, these bacteria became the target of MST efforts (20,21).…”