Antibiotic Susceptibility Profile and Slime Layer Formation of a Clinical Isolate of Streptococcus sanguinis from Infected Root Canals

Objective: This study examined susceptibility of the clinical isolate Streptococcus
sanguinis, isolated from an infected root canal to various antibiotics, and tested its
capacity to form a slime layer. Method: PCR and gel electrophoresis both confirmed it
as bacterial identification. The 16S rRNA gene sequence of S. sanguinis was determined
and compared to previously determined sequences in the NCBI (National Center for
Biotechnology Information) database. Growth of the isolate was determined to consist
of a strong ability to form a slime layer when grown on Congo red-modified Schaedler
agar medium. Results: GenBank records for the resulting sequences are under the
accession numbers PQ654829 and PQ654911. The antibiotic susceptibility profile was
high to levofloxacin, moderate to gentamicin, tobramycin and vancomycin, and
complete resistance to cefixime. Novelty: The results of this study provide important
information about the bacterium's virulence and antibiotic resistance.