Would topical Bactroban (mupirocin) be of benefit in addition to oral antibiotics (abx) for a cat bite?

Topical Mupirocin (Bactroban) for Cat Bite Infections

Topical mupirocin (Bactroban) is not recommended as an addition to oral antibiotics for cat bite wounds, as it does not target the primary pathogens involved in cat bite infections, particularly Pasteurella multocida. 1

Microbiology of Cat Bite Infections

• Cat bites contain an average of 5 different bacterial species per wound, including both aerobic and anaerobic bacteria 1
• Pasteurella multocida is found in approximately 75% of cat bite wounds and is the predominant pathogen requiring systemic antibiotic coverage 1, 2
• Staphylococci and streptococci are present in ~40% of cat bite wounds 1
• Anaerobic bacteria, including Bacteroides species, fusobacteria, Porphyromonas species, and peptostreptococci, are present in 65% of cat bites 1, 3

Why Topical Mupirocin Is Not Beneficial

• Mupirocin has excellent activity against staphylococci and streptococci but does not adequately penetrate to reach deep-seated infections that commonly occur with cat bites 4
• Cat bites frequently introduce bacteria deep into tissues, beyond the reach of topical antibiotics 3
• The polymicrobial nature of cat bite infections, particularly the presence of P. multocida, requires systemic antibiotic therapy that can reach adequate tissue concentrations 2

Recommended Treatment Approach

First-Line Oral Antibiotics

• Amoxicillin-clavulanate (875/125 mg twice daily) is the recommended first-line therapy for cat bite infections 1, 2
• Doxycycline (100 mg twice daily) is an excellent alternative with good activity against P. multocida, though some streptococci may be resistant 1, 5
• Penicillin plus dicloxacillin (500 mg four times daily for each) is another oral option 1

Medications to Avoid

• First-generation cephalosporins (e.g., cephalexin) should be avoided due to poor activity against P. multocida 1, 5
• Penicillinase-resistant penicillins (e.g., dicloxacillin) alone should be avoided 1
• Clindamycin alone should be avoided as it misses P. multocida 1

For Severe Infections

• Intravenous options include ampicillin-sulbactam, piperacillin-tazobactam, second-generation cephalosporins, or carbapenems 1, 5
• Hospitalization should be considered for systemic infection, rapidly progressing infection, deep tissue involvement, or immunocompromised hosts 5

Proper Wound Management

• Wounds should be thoroughly cleansed with sterile normal saline 1
• Superficial debris should be removed 1
• Infected wounds should not be closed 1
• Elevation of the injured body part accelerates healing 1
• Tetanus prophylaxis should be administered if vaccination status is outdated or unknown 1, 6

Follow-Up Recommendations

• Outpatients should be followed up within 24 hours either by phone or during an office visit 1
• If infection progresses despite appropriate therapy, hospitalization should be considered 5

Common Pitfalls to Avoid

• Underestimating the severity of cat bite infections (20-80% of cat bites become infected compared to only 3-18% of dog bites) 2
• Failing to obtain both aerobic and anaerobic cultures in cases of established infection 3
• Relying solely on topical antibiotics without systemic coverage 1
• Delaying treatment, which can lead to complications such as septic arthritis, osteomyelitis, or tendonitis 1, 7