Infection and the use of antibiotics in Crohn's disease.

Many patients with Crohn's disease present with the complications of infection. Hence, antibiotics play an important role in the medical management of acute inflammatory disease, persistent perianal disease and as prophylaxis for surgical operations. The author's group has demonstrated that bacteria colonize the serosa of the bowel in patients with Crohn's disease in 27% of cases. Furthermore, pathogenic bacteria could be recovered from the lymph nodes in 33% of patients with Crohn's disease, compared with only 5% in a controlled population. Extraintestinal bacterial colonization was, therefore, present in approximately half of all patients requiring an operation for Crohn's disease. The principal bacteria isolated at these sites were Escherichia coli, Streptococcus faecalis, Bacteroides fragilis, Proteus sp and diphtheroids. A prospective controlled trial on the use of 1 month's antimicrobial therapy in patients with relapse of Crohn's disease revealed that metronidazole was associated with a 57% response rate, compared with a response of only 17% in patients receiving no metronidazole. These interim findings suggest that metronidazole may have a role in the management of acute relapse in patients with Crohn's disease.