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Elastase activity of anaerobes isolated from amniotic fluid with preterm premature rupture of membranes
1Department of Obstetrics and Gynecology, School of Medicine, Gifu University, Japan.
Objective:
A total of 131 anaerobes isolated from amniotic fluid with preterm premature rupture of membranes and stored were examined for elastolytic activity by the method described by Williams et al (Lett Appl Microbiol 1988;7:173-6).
Study Design:
Each strain was spot inoculated on a Columbia blood agar plate containing 1% solubilized elastin and incubated for 5 days under anaerobic conditions. Undigested elastin was precipitated by flooding trichloroacetic acid solution onto the plate, and a clear zone was visible as the elastolytic reaction around the spot of bacterial growth.
Results:
Ninety-three (71.0%) of 131 organisms showed a positive elastolytic reaction. Eleven of 20 strains (55.0%) of Peptostreptococcus magnus, 9 of 18 strains (50.0%) of Peptostreptococcus micros, 12 of 12 strains (100.0%) of Fusobacterium nucleatum, 15 of 28 strains (53.6%) of Bacteroides fragilis, 8 of 15 strains (53.3%) of Bacteroides thetaiotaomicron, and 38 of 38 strains (100.0%) of Prevotella bivia were elastolytic.
Conclusion:
Anaerobic bacterial species prevalent in the normal vaginal flora that were isolated from amniotic fluid of women with preterm rupture of membranes produced elastolytic activity, plausibly inducing the destruction of host constitutive components.
Insights
Many common vaginal anaerobes isolated from amniotic fluid exhibit elastolytic activity. This bacterial enzyme production may contribute to the breakdown of host tissues during preterm premature rupture of membranes.
Area of Science:
- Microbiology
- Obstetrics & Gynecology
Background:
- Preterm premature rupture of membranes (PPROM) is a significant obstetric complication.
- Anaerobic bacteria are frequently found in the vaginal flora and can be isolated from amniotic fluid in cases of PPROM.
- Elastolytic activity, the ability to degrade elastin, is a potential virulence factor for bacteria.
Purpose of the Study:
- To investigate the prevalence of elastolytic activity among anaerobic bacteria isolated from amniotic fluid of women with PPROM.
- To determine which specific anaerobic species possess this enzymatic capability.
Main Methods:
- A total of 131 anaerobic bacterial strains were isolated from amniotic fluid samples of women diagnosed with PPROM.
- Bacterial elastolytic activity was assessed using a qualitative method on Columbia blood agar plates containing solubilized elastin.
- Positive elastolytic activity was indicated by a clear zone around bacterial growth after incubation and precipitation of undigested elastin.
Main Results:
- Out of 131 anaerobic isolates, 93 (71.0%) demonstrated elastolytic activity.
- Species with high prevalence of elastolytic activity included Fusobacterium nucleatum (100.0%) and Prevotella bivia (100.0%).
- Other tested species like Peptostreptococcus magnus (55.0%), Peptostreptococcus micros (50.0%), Bacteroides fragilis (53.6%), and Bacteroides thetaiotaomicron (53.3%) also exhibited significant elastolytic capabilities.
Conclusions:
- Anaerobic bacteria commonly found in vaginal flora and implicated in PPROM possess significant elastolytic activity.
- This enzymatic activity may play a role in the pathogenesis of PPROM by degrading host connective tissues.
- Further research is warranted to elucidate the precise mechanisms and clinical significance of bacterial elastolysis in PPROM.