Penicillin concentration in saliva and its influence on bacterial interference

Area of Science:

• Microbiology
• Pharmacology
• Oral Health

Background:

• Oral streptococci, including alfa- and beta-hemolytic strains, are key components of the oral microbiome.
• Penicillin is a widely used antibiotic for bacterial infections, including those affecting the oral cavity.
• Understanding antibiotic interactions within the oral microbiome is crucial for effective treatment and preventing resistance.

Purpose of the Study:

• To investigate the effect of varying penicillin concentrations on the interference between alfa- and beta-streptococci.
• To correlate in-vivo penicillin levels in saliva with observed changes in streptococcal populations.
• To elucidate the impact of penicillin on the survival and interaction dynamics of oral streptococci.

Main Methods:

• Administration of oral penicillin tablets and measurement of salivary antibiotic concentrations.
• Quantification of alfa- and beta-streptococcal populations in saliva over time.
• Determination of Minimum Inhibitory Concentrations (MIC) for penicillin against relevant streptococcal strains.

Main Results:

• Rapid penicillin release from oral tablets achieved saliva concentrations above MIC within 2 minutes, reducing alfa-streptococcal flora.
• Penicillin levels exceeding the MIC for alfa-streptococci promoted the prolonged survival of beta-streptococci.
• A synergistic effect was observed between penicillin and interfering alfa-streptococcal strains at specific penicillin concentration thresholds.

Conclusions:

• Oral penicillin administration significantly alters the dynamics of streptococcal populations in the mouth.
• Penicillin's effect on oral streptococci is concentration-dependent, with potential for promoting survival of certain strains at sub-optimal inhibitory levels.
• These findings highlight the complex interplay between antibiotics and microbial communities in the oral environment, impacting therapeutic outcomes.