Micromonas micros: identification using PCR and biochemical tests

Introduction: Micromonas micros (Peptostreptococcus micros) is a strict anaerobic cocci frequently isolated from mouth and gut, which is also associated with periodontal diseases and uterine infections. Objective: The aim of this study was to compare the identification of Micromonas micros by PCR ( polymerase chain reaction ) using specific primers based on 16S rRNA and by biochemical profile using Rapid Id 32A (bio Merieux). Method: DNA from 223 strains presumptively identificated as M. micros isolated from patients with different periodontal conditions was obtained, and submitted to PCR. Following this, 28 PCR-positive strains and 48 PCR-negative strains were submitted to biochemical tests. Results: Among 223 tested strains by PCR method, 86 showed to be negative for this reaction. Neverthless, from 48 PCR-negative strains submitted to the biochemical tests, 38 were classified as M. micros, 5 as M. micros but with a doubtful profile and 5 showed to be Finegoldia magna (Peptostreptococcus magnus ). From 28 PCR-positive strains submitted to biochemical tests, only 2 did not exhibit a M. micros profile. Conclusion: Data suggest that new molecular methods based on 16S rDNA should be evaluated for the correct species identification of Micromonas micros. (Grants : 00/10112-0 and 00/10047-4FAPESP/ São Paulo – Brazil)