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Cell-associated collagenolytic activity by group B streptococci
R J Jackson1, M L Dao, D V Lim
1Department of Biology, University of South Florida, Tampa 33620-5150.
Abstract:
Group B streptococci (GBS) are important pathogens in neonatal sepsis, pneumonia, and meningitis. The ability of GBS to invade the collagen-rich amniotic membrane of the placenta has been shown in vitro. In the presence of GBS, the collagen fibrils of the amnion appear disordered, suggesting a role for GBS in premature rupture of membranes. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Sephadex G-200 column chromatography, and gelatin zymograms were used in this study to characterize cell-associated collagenolytic activities of GBS. The synthetic peptide 2-furanacryloyl-Leu-Gly-Pro-Ala (FALGPA), which mimics the primary structure of collagen, was degraded by GBS USF704, a clinical isolate from the placenta of a septic newborn. Cells of GBS USF704 (9 x 10(7) CFU/ml) hydrolyzed 902 nmol of FALGPA over a 24-h period. As reported for zinc metalloenzymes such as collagenase, the hydrolysis of FALGPA by GBS was inhibited by addition of EDTA or 1,10-phenanthroline. Boiling of the cells resulted in loss of activity, while higher activity was observed with crude GBS cell lysates (hydrolysis of 970 nmol of FALGPA in 1.5 h). Antiserum raised against collagenase from Clostridium histolyticum was found to cross-react with cell-associated proteins produced by GBS and to inhibit GBS FALGPA hydrolysis. Twenty-five additional GBS clinical isolates were screened and found to have various levels of FALGPA hydrolytic activity. These observations suggest a cell-associated collagenolytic activity by GBS which may be involved in premature rupture of membranes and neonatal disease.
Insights
Group B streptococci (GBS) possess collagen-degrading enzymes that may contribute to premature rupture of membranes. This study identifies and characterizes GBS collagenolytic activity, potentially linking it to neonatal diseases.
Area of Science:
- Microbiology
- Biochemistry
- Pathogenesis
Background:
- Group B streptococci (GBS) are significant causes of neonatal infections, including sepsis, pneumonia, and meningitis.
- GBS invasion of the placenta's amniotic membrane and potential role in premature rupture of membranes (PROM) have been observed.
- Disordered collagen fibrils in the amnion in the presence of GBS suggest enzymatic activity.
Purpose of the Study:
- To characterize the cell-associated collagenolytic activities of GBS.
- To investigate the potential role of GBS collagenase in neonatal disease and PROM.
Main Methods:
- Utilized sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Sephadex G-200 column chromatography, and gelatin zymograms.
- Assessed the degradation of the synthetic collagen-mimicking peptide FALGPA by GBS.
- Investigated the effects of EDTA, 1,10-phenanthroline, heat, and anti-collagenase antiserum on GBS activity.
Main Results:
- GBS USF704 hydrolyzed FALGPA, indicating collagenolytic activity.
- Activity was inhibited by EDTA and 1,10-phenanthroline, characteristic of zinc metalloenzymes.
- Heat inactivated the enzyme, while cell lysates showed higher activity.
- Antiserum against Clostridium histolyticum collagenase cross-reacted with GBS proteins and inhibited FALGPA hydrolysis.
- Twenty-five additional GBS isolates exhibited varying levels of FALGPA hydrolytic activity.
Conclusions:
- GBS possesses cell-associated collagenolytic activity.
- This activity may contribute to the pathogenesis of premature rupture of membranes.
- The findings suggest a potential mechanism for GBS-related neonatal disease.