Evaluation of 15 motility media and a direct microscopic method for detection of motility in enterococci.
Isolation of motile, vanC enterococci has yet to be a major infection control concern; however, rapid detection still is important. We evaluated 15 motility media from three manufacturers and a 2-h direct microscopic method for accurate detection of 89 enterococcal strains, including 72 vanC enterococcal strains. Resistance genes were confirmed by a multiplex PCR method with the vanC gene detected in all motile enterococci. Motility in the 72 vanC enterococci was detected at 30 degrees C within 72 h in BD Biosciences motility nitrate medium and in Remel motility B medium, motility B medium supplemented with methyl-alpha-D-glucopyranoside (investigational), motility S medium, motility test medium, and motility test medium with tetrazolium indicator. Motility was also observed for all vanC enterococci with the 2-h direct (30 degrees C incubation) microscopic detection method. All Enterococcus faecalis and Enterococcus faecium isolates were observed to be nonmotile in all media and by the direct microscopic method. Since differences between the various motility media tested were observed, the medium used for detection of enterococcal motility must be selected carefully.
Van Horn
Kenneth
K
Microbiology, Westchester Medical Center, and New York Medical College, Valhalla, New York 10595, USA. vanhornk@wcmc.com
Tóth
Clara
C
Kariyama
Reiko
R
Mitsuhata
Ritsuko
R
Kumon
Hiromi
H
D001426:Bacterial Proteins / Q000235:genetics; D001431:Bacteriological Techniques; D003470:Culture Media; D016983:Enterococcus / Q000235:genetics* / Q000472:pathogenicity / Q000502:physiology*; D005798:Genes, Bacterial; D006801:Humans; D008853:Microscopy / Q000379:methods; D009068:Movement; D016133:Polymerase Chain Reaction / Q000379:methods; D020713:Vancomycin Resistance / Q000235:genetics
D001426:Bacterial Proteins; D003470:Culture Media; C079914:VanC protein, Bacteria