Streptococcus mutans is gram positive bacteria and present in cocci and chain form. It is
facultative anaerobes, non-motile, catalase negative and non-spore forming, lactic acid bacteria
and normally found in oral cavity (Rao and Austin 2014). S.mutans involve in endocarditis, dental
caries, have ability to adhere to the cardiac tissue and cause chronic infective endocarditis. Caries
is caused of tooth decay and tooth loss in adult and school aged children. Many microorganisms
can cause dental caries namely S. mutans, S.sanguis, s.mitis, S.salivarius and S. sobrinus but
S.mutans have major role in developing of dental caries. Dental caries is major problem around
the globe in these days. Generally it treated with antibiotics. But now a day’s due to increase in
antibiotic resistance, recently plant extracts and plants parts are being in use as treatment and oral
hygiene. It is therefore, present research was designed to analyze the plant extract which having
antimicrobial activity against oral bacteria and have been used traditionally for cleaning the teeth.
Azadirachta indica (Neem), Acacia nilotica (Kikar), Pongamia pinnata (Sukhchein) and
Salvadora persica (Peelu) were used to check the activity against S. mutans. Aqueous and
methanolic extracts of bark were prepared of selected plants. Extract potential against S. mutans
was checked through well diffusion and minimum inhibitory concentration (MIC) assay. Dental
caries samples were collected from different hospitals from Lahore. Twenty five samples were
processed to isolate S.mutans. Out of twenty five samples twenty isolates of S.mutans were isolated
which showed resistance against bacitracin, confirmed by disk method.. Biochemical tests such
as hemolysis test and sugar fermentation tests were also done for the confirmation of S. mutans.
Furthermore, antibiotic sensitive test was performed to check the sensitive pattern of S. mutans All
S. mutans were resistant to oxacillin, cefmetazole and cephaloridine, and sensitive to streptomycin
Summary
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and gentamycin. S. mutans showed high level of resistance to ceftriaxone (90%), cefixim (90%),
chloramphenicol (65%) and vancomycin (60%), and intermediate level of resistance to
sulfamethoxazole/Trimethoprim (40%) and ciprofloxacin (30%), and low level of resistance to
amoxicillin (25%), delfopristin (25%) ampicillin (20%), fusidic acid (20%) and linezolid (5%).
MIC value for aqueous extract for Salvadora persica, Azadirachta indica, Acacia nilotica,
Pongamia pinnata are 24-48, 3-48,0,180-12 and >48 mg/ml respectively, and MIC value for
methanolic extract are 0.09-12, 3->48, 0.376-6 and 1.5-24 mg/ml respectively. This in vitro study
gives us natural antimicrobial plants which can help us to control dental caries and endodontic
infections. The effects of these extracts might be beneficial if incorporated in tooth paste, mouth
rinses and dental products to reduce plaque and dental caries.