Prevalence of Streptococcus mutans among Patients Presenting Tooth Decay Symptoms in Murtala Muhammed Specialist Hospital, Kano State, Nigeria

Dental caries remains among the most common oral health problems globally, with Streptococcus mutans being a key etiological agent. Understanding the prevalence of this bacterium among symptomatic patients is crucial for developing targeted preventive and therapeutic strategies. This study aimed to determine the prevalence of Streptococcus mutans among patients presenting with tooth decay symptoms at Murtala Muhammed Specialist Hospital, Kano State, Nigeria. A cross-sectional study was conducted involving 400 patients. Oral dental plaque samples were aseptically collected from patients with dental caries at Murtala Muhammed Specialist Hospital, Kano's dental clinic, and transported in sterile peptone water for microbiological analysis. The samples were cultured on chocolate agar and incubated in a candle jar at 37°C for 24 hours. Bacterial identification involved colony morphology, Gram staining, catalase, optochin sensitivity tests, and confirmation using the API 20 Strep system. Antibiotic susceptibility testing was performed using the disk diffusion method with five antibiotics and interpreted based on CLSI 2020 guidelines. Out of 400 samples processed, 351 (87.8%) yielded positive cultures, all of which were Gram-positive cocci. Among the 116 suspected Viridans streptococci, 87 (75.0%) were confirmed as Streptococcus mutans. Antibiotic susceptibility testing showed the highest resistance to tetracycline (67.8%), followed by erythromycin (28.7%) and ciprofloxacin (27.6%). The study found a high prevalence of Streptococcus mutans (75.0%) among patients with dental caries, with significant resistance observed to tetracycline (67.8%). These findings underscore the need for targeted oral health interventions and prudent antibiotic use in dental practice.