A Novel Selective Medium for Isolation of Bacteroides fragilis from Clinical Specimens

Abstract

A novel Bacteroides fragilis selective (BFS) medium, consisting of a brain heart infusion agar base supplemented with yeast extract, cysteine hydrochloride, bile salts, vitamin K, hemin, glucose, esculin, ferric ammonium citrate, bromothymol blue, gentamicin, kanamycin, and novobiocin, was evaluated. When BFS agar was tested with a collection of 303 bacteria of different genera, it allowed the growth of B. fragilis as large yellow colonies, with blackening of the medium after 48 h of anaerobic incubation, while the growth of most other anaerobes, facultative anaerobes, and aerobes was inhibited. In a prospective comparison of BFS agar with a routinely used medium (neomycin blood agar) in 1,209 clinical specimens, 60 B. fragilis bacteria were detected on BFS agar while 46 were detected on the routine agar (McNemar's test, P ϭ 0.008). In conclusion, this novel medium may be added to improve the recovery of B. fragilis in clinical specimens and to facilitate surveillance of antimicrobial-resistant strains.

Rapid detection ofcfiAmetallo-β-lactamase-producingBacteroides fragilisby the combination of MALDI-TOF MS and CarbaNP

“…The isolates were recovered from wounds (n=182), abdominal and pelvic (n=84), genital (n=46) and perianal (n=44) regions, blood (n=32), bile (n=16) and other specimens (n=20). In the two laboratories, anaerobic blood agar supplemented with haemin, vitamin K and neomycin was used for recovery of B. fragilis 16. The isolates were initially identified as B. fragilis by MALDI-TOF MS and were stored in MicroBank (Pro-Lab Diagnostics) at −80°C.…”

Biological Indicators for Fecal Pollution Detection and Source Tracking: A Review

“…Unlike facultative anaerobic FIB, the isolation and cultivation of Bacteroides cells require anoxic chambers, which is costly, time-consuming and labor-intensive [162]. Bacteroides can grow at 37 • C in many selective media, such as Brain Heart Infusion medium, Bacteroides Bile Esculin agar, and Blood Hemin Vitamin K medium containing antibiotics [162][163][164]. In most applications, Bacteroides grows into visible colonies on plates within 24 h, and colonies will be large enough to enumerate in 36 and 48 h. Some Bacteroides species can be identified to the species level within four hours by a few biochemical tests, such as the API ZYM system that detects activities of Bacteroides-specific enzymes [165].…”

Assessement of Physicochemical Properties of Some Boreholes Located Near Waste Dump Sites in Katsina Metropolis, Nigeria

“…Water is an essential component for life on Earth, which contains minerals extremely important in human nutrition [1]. However, the dramatic increase in population resulted in an enormous consumption of the world's water reserves [2]. Everything is originated from water and everything is dependent on water for them.…”