The evaluation of a mupirocin-based selective medium for the enumeration of bifidobacteria from probiotic animal feed

• Published in: Journal of microbiological methods Vol. 57; no. 1; pp. 9 - 16
• Main Authors: Simpson, P.J., Fitzgerald, G.F., Stanton, C., Ross, R.P.
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier B.V 01.04.2004; Elsevier Science
• Subjects: Aldehyde-Lyases - metabolism; Animal Feed - microbiology; Animals; Anti-Bacterial Agents - pharmacology; Bacillus; Bacteriological methods and techniques used in bacteriology; Bacteriology; Bifidobacteria; Bifidobacterium; Bifidobacterium - growth & development; Bifidobacterium - metabolism; Biological and medical sciences; Colony Count, Microbial; Culture Media - pharmacology; Enterococcus; Feed and pet food industries; Food industries; Fundamental and applied biological sciences. Psychology; Lactobacillus; Lactococcus; Microbiology; Mupirocin; Mupirocin - pharmacology; Pediococcus; Probiotic animal feed; Probiotics; Saccharomyces cerevisiae; Bifidobacteria; Probiotic animal feed; Mupirocin; Culture medium; Enumeration; Actinomycetaceae; Animal feeding; Bifidobacterium longum; Actinomycetales; Bacteria; Actinomycetes; Inhibition; Detection; Bifidobacterium bifidum; Comparative study
• ISSN: 0167-7012; 1872-8359
• DOI: 10.1016/j.mimet.2003.11.010

In this study, MRS medium supplemented with cysteine hydrochloride and mupirocin, termed Bifidobacterium selective medium (BSM) was found to be elective for bifidobacteria but inhibitory to a wide range of non-bifidobacteria strains commonly included in probiotic animal feed. Bacilli, lactobacilli, lactococci and streptococci failed to form colonies on BSM and enterococci, pediococci and propionibacteria formed colonies <0.5 mm in diameter. Bifidobacteria formed colonies >1 mm in size and could be readily distinguished. The addition of nystatin to BSM further inhibited Saccharomyces cerevisiae. BSM was successfully used to enumerate the bifidobacteria components, confirmed through fructose-6-phophate-phosphoketolase detection, present in two commercial probiotic feeds. The medium is recommended for the enumeration of bifidobacteria from animal feeds especially when not a numerically dominant component.