Quantitative determination of gelatinase activity among enterococci

K. Kanemitsu, T. Nishino, H. Kunishima, N. Okamura, H. Takemura, H. Yamamoto, M. Kaku

Research output: Contribution to journalArticlepeer-review

47 Citations (Scopus)


Gelatinase, hemolysin and aggregation substance have all been reported to be virulence factors of enterococci. In this study, gelatinase production was investigated in isolates of Enterococcus faecalis (n = 93), E. faecium (n = 49) and E. avium (n = 36) recovered from hospitalized patients. Gelatinase was detected in 45% of E. faecalis isolates, but could not be detected in E. faecium and E. avium. Gelatinase activity was then measured by radial diffusion for the 42 gelatinase-positive E. faecalis isolates. To convert gelatinase activity into proteinase K activity, a standard curve was produced by placing different concentrations of proteinase K into wells in the gelatine plate. Gelatinase activity per E. faecalis colony ranged from 2.6 × 10-7 to 2.2 × 10-5 μg/ml, proportionate to the activity of proteinase K. An approximately 84-fold difference in gelatinase concentration was observed between the colony producing the highest amount and that producing the lowest amount. This method may be useful for determining the virulence of given isolates in relation to gelatinase production as it is quick, easy and inexpensive to perform.

Original languageEnglish
Pages (from-to)11-16
Number of pages6
JournalJournal of Microbiological Methods
Issue number1
Publication statusPublished - 2001


  • Enterococci
  • Gelatinase
  • Radial diffusion assay
  • Virulence factor

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology
  • Microbiology (medical)


Dive into the research topics of 'Quantitative determination of gelatinase activity among enterococci'. Together they form a unique fingerprint.

Cite this