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Proteolytic activity in Serratia marcescens clinical isolates

R Coria-Jiménez1, C Zárate-Aquino, O Ponce-Ponce

  • 1Laboratory of Experimental Bacteriology, National Institute of Pediatrics, México City, 04530 México. rafaelcoria@yahoo.com

Folia Microbiologica
|July 21, 2004
PubMed

Insights

Clinical isolates of Serratia marcescens (S. marcescens) produce exoproteinases linked to virulence. Proteinase activity and origin site correlated with lethal dose 50 (LD50), with a common 57.5-kDa enzyme found in all strains.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Pathogenesis

Background:

  • Serratia marcescens (S. marcescens) is an opportunistic pathogen.
  • Exoproteinases are virulence factors in many bacteria.
  • Understanding S. marcescens exoproteinase production is crucial for assessing its pathogenic potential.

Purpose of the Study:

  • To investigate exoproteinase production in clinical isolates of S. marcescens.
  • To determine the relationship between exoproteinase activity, site of origin, and virulence (LD50).
  • To characterize the exoproteinases produced by these isolates.

Main Methods:

  • Analysis of 64 clinical isolates of S. marcescens.
  • Quantification of exoproteinase activity.
  • Determination of lethal dose 50 (LD50) for virulence assessment.
  • Monitoring exoproteinase production over a 14-hour incubation period.

Main Results:

  • Exoproteinase production was confirmed in all 64 clinical isolates.
  • A significant correlation was observed between the site of origin, proteinase activity, and LD50.
  • Exoproteinase production varied during incubation, with a 57.5-kDa proteinase consistently detected in all strains.
  • Exoproteinase production was directly related to S. marcescens strain virulence.

Conclusions:

  • Exoproteinase production is a common characteristic of clinical S. marcescens isolates.
  • The level of exoproteinase activity and specific enzyme profiles are associated with bacterial virulence.
  • These findings highlight the role of exoproteinases in S. marcescens pathogenesis.

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