Ans. (c) Topical bacitracinRef: Harrison TB of internal medicine - 19th ed - page 959* The anterior nares is the most common site of staphylococcal colonization in humans.* It is because of attachment of S. aureus to keratinized epithelial cells of the anterior nares.* Factors that contribute to colonization include the# Influence of other resident nasal flora and their bacterial density,# Host factors# Nasal mucosal damage (use of inhalational drugs)Colonization areas are:* Anterior nares* Damaged skin* Groin (umbilicus)* Oropharynx* Primary prevention of S. aureus infections in the hospital setting involves hand washing and careful attention to appropriate isolation procedures.To eradicate the colonization:* Decolonization is with topical agents (e.g., mupirocin) to eliminate nasal colonization* Chlorhexidine baths to eliminate cutaneous colonization with S. aureus