Cell-associated collagenolytic activity by group B streptococci

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 107 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.

An Extracellular Protease ofStreptococcus gordoniiHydrolyzes Type IV Collagen and Collagen Analogues

“…Indeed, highly proteolytic strains of Enterococcus faecalis were reported to be more virulent than weakly proteolytic strains in a rabbit model of infective endocarditis (15). A cell-associated collagenase has also been detected in group B streptococci (18), and it hydrolyzes the same collagen analogs as the S. gordonii protease reported here does. In addition, proteases may be important in normal processing of other surface proteins of streptococci; for example, the glycosyltransferase of S. sanguis is converted from 174 to 156 kDa at the cell surface (12).…”

Characterization of PepB, a group B streptococcal oligopeptidase

“…Enzyme purification. Intact cells of GBS were found to exhibit weak FALGPA-hydrolyzing activity, and in agreement with the results reported by Jackson et al (8), much higher activity was found in cell lysates. Enzyme was therefore purified from the lysate of a cell pellet obtained from 60 liters of a log-phase culture (A 650 ϭ 0.8) of strain 3502 of GBS, a serotype III strain that had been isolated from the blood of an infected infant.…”

“…The recent report by Jackson et al (8) of a collagenase produced by GBS appeared to be yet another example of the production of an enzyme of GBS capable of degrading a component of the extracellular matrix and, possibly, facilitating invasion. The investigators speculated that the enzyme might contribute to the premature rupture of membranes frequently associated with neonatal infections.…”

“…The investigators speculated that the enzyme might contribute to the premature rupture of membranes frequently associated with neonatal infections. Jackson et al (8) assayed the collagenase activity of GBS by using the synthetic substrate N- (3-[2-furyl]acryloyl)-Leu-Gly-Pro-Ala (FALGPA), which is hydrolyzed by all known collagenases and is thought to mimic the primary structure of collagen. We decided to isolate and purify the enzyme and further characterize it.…”

Bacterial collagenases and collagen-degrading enzymes and their potential role in human disease

“…Group B streptococci (Streptococcus agalactiae) have also been associated with PROM and subsequent neonatal sepsis, pneumonia, and meningitis. This organism produces an enzyme which is capable of hydrolyzing both amniotic collagen fibrils (25) and FALGPA (23,24).…”