A 55-year-old diabetic man presents with a painful, rapidly enlarging carbuncle on the back of his neck. Central fluctuance is present with multiple interconnected follicular openings draining pus. Gram stain shows Gram-positive cocci in clusters. Beyond incision and drainage, which systemic antibiotic would be MOST appropriate considering the current resistance pattern in India?
- A Penicillin V orally for 7 days
- B Cloxacillin 500 mg four times daily for 7–10 days ✓
- C Amoxicillin 500 mg three times daily for 5 days
- D Metronidazole 400 mg three times daily for 7 days
Explanation
A carbuncle is a deep follicular infection involving multiple hair follicles and subcutaneous tissue, most commonly caused by Staphylococcus aureus. In India, community-acquired strains are predominantly beta-lactamase producers (methicillin-susceptible S. aureus/MSSA), so a beta-lactamase-resistant penicillin such as cloxacillin (dicloxacillin or flucloxacillin in other regions) is the drug of choice for MSSA furunculosis/carbuncle. Penicillin V and amoxicillin are inactivated by staphylococcal beta-lactamase. Metronidazole covers anaerobes but not Staphylococcus. For MRSA, co-trimoxazole or doxycycline is used empirically.
Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.