Isolation and Identification of Streptococcus Mutans and Study of Biofilm Formation


  • Zahraa Dhafer Shamsulddin Department of Microbiology, College of Medicine, University of Babylon, Iraq
  • Ilham Abbas Bunyan Department of Microbiology, College of Medicine, University of Babylon, Iraq


Streptococcus mutans, Biofilm formation, TCP method


The samples were collected from soft deep caries lesion, from patients who were
visited to Medical Educational Clinics of the College of Dentistry / University of Al-Kufa,
during a period of five months from November 2022 to end of March 2023, provided the study's
100 participants with soft deep caries lesion specimens. The samples were grown in a number of
different media. After that, they spent 18-24 hours in a (37o
C) incubator. Colony morphology,
microscopy, and biochemical testing were first used by scientists to identify Streptococcus
mutans. Only 20% of the isolates were confirmed to be St. mutans from the 100 positive clinical
samples, the automated Vitek 2 system deployed GP-ID cards including 64 biochemical assays
to guarantee the isolates were indeed St. mutans. The approach promptly and accurately
identified 20 distinct bacterial isolates with probabilities ranging from 94% to 99.7%. In the
present study, it was used ELISA to distinguish between St. mutans isolates that produced
biofilms and those that did not, by using the median values of optical density (OD) at 570 nm (>
0.240, 0.120, and 0.120), bacterial biofilms cause chronic diseases that are difficult to treat.
Twenty distinct isolates were tested for their ability to form biofilm, 9(45%) were found to be
strong biofilm producers, while 11(55%) were rated as moderate biofilm producers.


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