title: 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 = 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.
authors.affiliation: Department of Microbiology and Carol Yu Centre for Infection, The University of Hong Kong, Queen Mary Hospital, Hong Kong Special Administrative Region, China plho@hkucc.hku.hk.
authors.forename: Pak-Leung
authors.identifier: 0000-0002-8811-1308
authors.initials: PL
authors.lastname: Ho
authors.affiliation: Department of Clinical Pathology, Kwong Wah Hospital, Hospital Authority, Hong Kong Special Administrative Region, China.
authors.forename: Lok-Yan
authors.initials: LY
authors.lastname: Ho
authors.affiliation: Department of Microbiology and Carol Yu Centre for Infection, The University of Hong Kong, Queen Mary Hospital, Hong Kong Special Administrative Region, China.
authors.forename: Chong-Yee
authors.initials: CY
authors.lastname: Yau
authors.affiliation: Department of Microbiology and Carol Yu Centre for Infection, The University of Hong Kong, Queen Mary Hospital, Hong Kong Special Administrative Region, China.
authors.forename: Man-Ki
authors.initials: MK
authors.lastname: Tong
authors.affiliation: Department of Microbiology and Carol Yu Centre for Infection, The University of Hong Kong, Queen Mary Hospital, Hong Kong Special Administrative Region, China.
authors.forename: Kin-Hung
authors.initials: KH
authors.lastname: Chow
mesh_terms: D000693:Anaerobiosis; D001431:Bacteriological Techniques / Q000379:methods*; D001442:Bacteroides Infections / Q000175:diagnosis* / Q000382:microbiology; D001441:Bacteroides fragilis / Q000254:growth & development* / Q000302:isolation & purification*; D003470:Culture Media / Q000737:chemistry*; D006801:Humans; D012641:Selection, Genetic
chemical_list: D003470:Culture Media
keywords: Bacteroides; media; selective medium