Background:Streptococcus mutans and Streptococcus sobrinus are main etiological agents of dental caries.Aim:The aim of the study was to isolate, identify, characterize, and determine the minimum inhibitory concentration (MIC) of S. mutans and S. sobrinus from caries-active subjects.Materials and Methods:Sixty-five plaque samples were collected from caries-active subjects aged between 35 and 44 years, processed and cultured on mitis salivarius bacitracin agar. All the bacterial isolates were subjected to morphotyping and the suspected colonies were identified by 16S rDNA sequencing. The S. mutans and S. sobrinus strains were characterized by biotyping and phylogenetic analysis. The MIC of ampicillin and erythromycin was determined by microtiter plate method.Results:Of the study population, 41 isolates displayed typical colony morphologies of S. mutans and S. sobrinus. The 16S rDNA sequencing results revealed that 36 isolates were S. mutans and 5 isolates were S. sobrinus. The biotyping of these isolates demonstrated three biotypes, namely, biotype I (n = 35), biotype III (n = 1), and biotype IV (n = 2). However, 3 isolates exhibited variant biotypes. The phylogenetic analysis revealed that the clinical strains of S. mutans and S. sobrinus clustered independently along with respective reference strains. The average MIC of ampicillin and erythromycin against S. mutans and S. sobrinus was 0.047 μg/ml and 0.39 μg/ml, respectively.Conclusion:The 16S rDNA sequencing was an impeccable method for S. mutans and S. sobrinus identification when compared with morphotyping and biotyping methods. The study also suggested that nonspecific bacteria might be involved in caries formation.

Dental caries is one of the oldest disease in the world and its causative agent is mutans streptococci (MS). Among MS, Streptococcus mutans and Streptococcus sobrinus are implicated in caries active subjects. The objective of this study was to identify and determine the antibiogram profile of S. mutans and S. sobrinus isolates. The dental plaque samples were collected from caries active subjects (aged 35-44 years) and later identified by 16S rDNA sequencing. Out of 65 clinical isolates 36 (55.38%) were S. mutans and 5 (7.69%) were S. sobrinus. Antibiogram profiling was performed to determine the susceptibility of 6 β-Lactam antibiotics (penicillin, ampicillin, cefotaxime, cephalothin, cefazolin and methicillin) and 2 non β-Lactam antibiotics (erythromycin and chloramphenicol) by disc diffusion method. All S. mutans and S. sobrinus isolates were susceptible to the antibiotics employed in this study. Penicillin and ampicillin were the most effective antibiotics against S. mutans and S. sobrinus isolates and no resistance found. The study concludes that all the isolates were susceptible to the antibiotics, and suggests that taking extra precaution while prescribing antibiotics will maintain the bacteria with less resistance. It also recommends to use an alternative prevention, such as a plant extract to avoid upcoming resistance.

Background and Aim: Enteric fever initiated by Salmonella enterica subsp. enterica serovar Typhi (S. Typhi) is among the most consistent disease worldwide, particularly in developing countries. The present study aimed to isolate and identify S. Typhi from typhoid suspected patients and determine their antibacterial susceptibility testing. Materials and Methods: Thirty blood samples were collected from typhoid suspected patients in Baghdad, Iraq. The samples were cultured on SS agar and XLD agar for screening of S. Typhi. The suspected colonies were picked up and subjected to Vitek 2 compact for biochemical identification and antibacterial susceptibility testing of the organisms. Molecular identification of the isolates was performed by real-time polymerase chain reaction (RT-PCR). Results: Black colonies were observed on cultured plates. Out of 30 samples, 27 and 29 isolates were identified as S. Typhi using Vitek 2 compact and RT-PCR, respectively. The data of the present study revealed that the strains of S. Typhi were showing multidrug resistance. All S. Typhi strains exhibited resistance to penicillins (ticarcillin and piperacillin), cephalosporins 4th G (cefepime), and monobactam (aztreonam). However, all the strains showed susceptibility against carbapenems (imipenem and meropenem) and tetracycline (minocycline). Conclusion: RT-PCR and Vitek 2 compact showed a high level of accuracy in the detection of S. Typhi. Multidrug resistance was observed, which is an alert for the reduction of antibiotic consumption.

BACKGROUND:Ruta graveolens is one of the most used phytomedicines. To date, there is no report of determining the bioactivity of R. graveolens against cariogenic causing bacteria (Streptococcus mutans and Streptococcus sobrinus).OBJECTIVE:The objective of the present study was to determine the antibacterial activity and metabolite profile of R. graveolens against S. mutans and S. sobrinus.MATERIALS AND METHODS:R. graveolens plant material was collected and processed in the month of February. The plant material was extracted by Soxhlet apparatus using methanol solvent. Two strains of S. mutans and two strains of S. sobrinus were isolated from dental caries-active participants and cultured on mitis salivarius-bacitracin agar. The antibacterial susceptibility testing of methanolic extract of R. graveolens was performed by disc diffusion method. The metabolite profile of the plant extract was determined using electrospray ionization-tandem mass spectrometry.RESULTS:The methanolic extract of R. graveolens showed a promising antibacterial activity against S. mutans and S. sobrinus. Two compounds named γ-fagarine and kokusaginine were identified from the methanolic extract of R. graveolens.CONCLUSION:The study concluded that R. graveolens contains significant antibacterial activity. However, further investigations are suggested to understand the anticaries properties of these pure compounds.

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