Antimicrobial susceptibility of Bacteroides fragilis group organisms in Hong Kong by the tentative EUCAST disc diffusion method.

This study used a recently developed EUCAST disc diffusion method to measure the susceptibility of 741 B. fragilis group isolates to six antibiotics. Isolates nonsusceptible to imipenem and metronidazole by the disc method were further investigated by E-test.

Rapid detection of metallo-β-lactamase-producing by the combination of MALDI-TOF MS and CarbaNP.

Aims: Carbapenem resistance in is emerging and is mainly attributed to insertion sequence (IS)-mediated activation of the carbapenemase gene . We investigated the use of matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS) and the CarbaNP assay for the rapid identification of these strains.

Methods: This study used the Bruker MALDI Biotype system and the mass spectra models generated by 20 reference strains (10 -positive and 10 -negative) in the ClinProTools software to identify 404 (71 -positive and 333 -negative) clinical isolates.

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

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.