OPTIMIZATION OF CULTURE CONDITIONS FOR A BIOFILM FORMING BACTERIUM

Abstract

Oral hygiene is an essential component of human health. Dental caries is one of the
most common diseases of man. Some specific species of bacteria are responsible for
the formation of this disease. In the present investigation, biofilm forming organisms
were isolated from dental caries affected man. The isolates were screened using test
tube assay, glass cover slip assay and microtiter plate assay. Different conditions for
better biofilm formation and antibiotic susceptibility of the selected organism were
investigated. Minimum inhibitory concentration (MIC) and minimum bactericidal
concentration (MBC) was also determined. Among the selected isolates, Streptococcus
mutans was found as better biofilm former that was finally selected for detailed study.
Optimized culture conditions for biofilm formation were found 37ºC for 24 hrs of
incubation with the medium pH 6.5 by the selected isolate. Glucose and yeast extract
induced biofilm formation. It was found that the selected isolate was sensitive to
ciprofloxacin and tetracycline; intermediate to chloramphenicol and gentamicin; and
resistant to amoxicillin, ampicillin, penicillin, cefixime and erythromycin. Results of this
study suggest reducing excessive consumption of sugary foods and drinks to prevent
the occurrence of dental caries. In case of therapeutic use, antibiotics should be given
depending on the basis of antibiotic susceptibility.