What is the treatment of choice for Actinomyces israelii infections?

• A. Metronidazole
• B. Ampicillin
• C. Clindamycin
• D. Ciprofloxacin

Answer: (B)

Actinomyces israelii is a Gram-positive anaerobic bacterium that is often involved in chronic, suppurative infections, which can be particularly prevalent in the oral and maxillofacial regions. The characteristic treatment for infections caused by Actinomyces israelii is high-dose penicillin or ampicillin, due to the organism's sensitivity to beta-lactam antibiotics.

Ampicillin serves as a broad-spectrum antibiotic that is effective against most strains of Actinomyces, making it a preferred choice in managing these infections. The use of ampicillin helps to ensure that the bacterial cell wall is compromised, leading to effective inhibition and eventual eradication of the organism.

In comparison, while Metronidazole and Clindamycin can also be effective against anaerobic bacteria, they are not the primary choice for Actinomyces infections. Metronidazole is particularly effective against certain protozoa and anaerobic bacteria but does not have as specific an action against Actinomyces as ampicillin does. Clindamycin is used for various types of infections, including those due to anaerobes, but it is often reserved for cases where there is a penicillin allergy or when the organism shows resistance to penicillin