Antibiotic Therapy for Common Infections

Introduction to Antibiotic Therapy

The American Academy of Otolaryngology-Head and Neck Surgery, American Academy of Pediatrics, and Infectious Diseases Society of America provide guidelines for antibiotic therapy in common infections, including combination therapy and antibiotic selection 1, 2, 3

Combination therapy with Clindamycin (300-450 mg orally three times daily) plus a third-generation cephalosporin (cefixime or cefpodoxime) is recommended by the American Academy of Otolaryngology-Head and Neck Surgery 1
Macrolide antibiotics alone are not recommended due to high resistance rates of S. pneumoniae (>40%), and trimethoprim-sulfamethoxazole alone is also not recommended due to high resistance rates in both S. pneumoniae (50%) and H. influenzae (27%), as advised by the American Academy of Otolaryngology-Head and Neck Surgery 1
Amoxicillin-clavulanate 875/125 mg twice daily can be used for excellent coverage against common pathogens, including Pasteurella multocida, Staphylococci, streptococci, and Anaerobic bacteria, as supported by the Infectious Diseases Society of America and the American College of Physicians 4, 5, 6
Fluoroquinolones (ciprofloxacin or levofloxacin) plus metronidazole can be used for anaerobic coverage, with a moderate strength of evidence 7, 4, 5

Aerobic and anaerobic cultures from the wound are essential for identifying the causative pathogens, with blood cultures recommended if there are signs of systemic infection, as recommended by the Infectious Diseases Society of America and the Clinical Infectious Diseases guidelines 3
Tissue biopsy is preferred over surface swabs for accurate pathogen identification, and wound culture should include aerobic and anaerobic cultures from the wound site, as well as a Gram stain to assess for inflammation markers, contamination, and microorganisms, according to the Infectious Diseases Society of America and the Clinical Infectious Diseases guidelines 3
Clean wound thoroughly before specimen collection to ensure accurate culture results, and remove topical antimicrobials that could affect culture results, as recommended by the Clinical Infectious Diseases guidelines and the Infectious Diseases Society of America 3
Thoroughly irrigate the wound until there is no obvious debris or foreign matter, and use running tap water or sterile saline solutions rather than antiseptic agents, as recommended by the American Heart Association, to prevent infection in patients with cat bites 8

For mild to moderate infections, a fluoroquinolone (levofloxacin 500mg daily or moxifloxacin 400mg daily) + metronidazole (500mg twice daily) for 7 days is recommended by the American Academy of Otolaryngology-Head and Neck Surgery 9
For severe infections, IV therapy with moxifloxacin or levofloxacin (750mg/day) may be considered, as suggested by the Centers for Disease Control and Prevention 10
Drainage of the abscess is essential and should be performed concurrently with antibiotic therapy, as emphasized by the American Academy of Otolaryngology-Head and Neck Surgery 9
The duration of therapy should typically be 5-7 days, but may be extended if improvement is not seen, although the exact duration may vary depending on the clinical guidelines 9

Surgical management should be considered if an abscess has formed, deep structures are involved, there is evidence of necrotic tissue, or a foreign body is suspected, with thorough debridement of necrotic tissue, irrigation with sterile saline or dilute povidone-iodine solution, drainage of any purulent collections, and removal of foreign bodies if present 7
High-risk patients, such as immunocompromised patients, elderly, patients with cirrhosis or asplenia, and patients with severe comorbidities, require broader spectrum antibiotics, closer monitoring, and possible hospitalization, with a moderate strength of evidence 4, 11, 12, 13
Indications for hospitalization include severe infections with systemic symptoms, deep infections involving tendons or joints, hand infections, and immunocompromised patients with moderate to severe infections, with a high strength of evidence 4, 14

Prophylactic antibiotics are recommended for all dog bites to the hand, deep puncture wounds, wounds requiring surgical debridement, immunocompromised patients, and wounds involving joints, tendons, or bones, with amoxicillin-clavulanate being the prophylactic antibiotic of choice, with a moderate strength of evidence 15, 6
Tetanus toxoid (0.5 mL intramuscularly) should be administered if vaccination status is outdated or unknown, with a strength of evidence based on clinical guidelines 4
Rabies prophylaxis should be considered for all feral and wild animal bites, with consultation of local department of health regarding risks and benefits, and if indicated, rabies immunoglobulin on day 0, followed by rabies human diploid cell vaccination, as recommended by the Infectious Diseases Society of America 4
Follow-up within 24-48 hours to assess for signs of infection, such as increasing pain, erythema, swelling, or purulent drainage, is recommended, with a moderate strength of evidence 4, 6, 14