Differential Diagnosis for Postoperative Infection
The patient's symptoms of high fever and foul-smelling wound drainage on postoperative day 1 suggest a surgical site infection. The following differential diagnoses are considered:
- Single most likely diagnosis
- Gram-positive cocci: This is the most likely isolate, as Staphylococcus aureus and coagulase-negative staphylococci are common causes of surgical site infections, particularly in the early postoperative period. These bacteria can produce virulence factors that lead to the observed symptoms.
- Other Likely diagnoses
- Gram-negative rods: Enteric gram-negative rods, such as Escherichia coli and Klebsiella pneumoniae, can also cause surgical site infections, especially if the surgery involved the gastrointestinal tract or genitourinary system.
- Anaerobic gram-negative rods: Bacteroides fragilis and other anaerobic gram-negative rods can cause infections in surgical sites, particularly if the surgery involved the gastrointestinal tract or female reproductive system.
- Do Not Miss diagnoses
- Clostridioides difficile: Although less likely, C. difficile infection can cause severe diarrhea and foul-smelling discharge, and is a potentially life-threatening condition that requires prompt diagnosis and treatment.
- Group A Streptococcus: This bacterium can cause severe, necrotizing soft tissue infections, which can be life-threatening if not promptly recognized and treated.
- Rare diagnoses
- Gram-negative cocci: While Neisseria species can cause infections, they are less commonly associated with surgical site infections.
- Fungal infections: Candida species and other fungi can cause surgical site infections, particularly in immunocompromised patients or those with prolonged exposure to broad-spectrum antibiotics. However, these infections are relatively rare in the early postoperative period.