[Factors responsible for post-operative infection]

Post-operative infection is often due to a combination of several factors. A decrease in immune defence processes represents the first factor. This is seen in situations such as malnutrition (undernourishment or obesity), alcoholism, diabetes, neoplasms, infections and old age. It may also be induced by therapy such as immunodepressants, antimitotic chemotherapy, corticosteroids and radiotherapy. Finally, certain antibiotics have been accused of reducing immune defences. The second factor responsible for infection is bacterial flora. Errors such as broad spectrum antibiotic therapy prescribed in the presence of unexplored fever, or changed repeatedly, are responsible for imbalance in the bacterial flora and the acquisition of resistance to antibiotics. These errors firstly increased the prevalence of infections and, secondly their severity and the difficulty of their treatment. The last factor responsible for infection is rupture of the natural barriers formed by the skin and mucosae. This is related on the one hand to surgery itself and, secondly, to the intensive care techniques surrounding the surgical act: venous catheterization above all, but also bladder catheterization, tracheal intubation, etc.