[Rectal ulcer infected by Mycobacterium fortuitum. Apropos of 4 cases]

From October 1986 to November 1988, 4 cases of rectal ulcers from which M. fortuitum was isolated were observed. The patients, all women, were respectively 24, 83, 85 and 86 years old. The complaints were: anorectal pain, rectal bleeding and stools mixed with glairy material. The ulcers were situated in the anterior, posterior or lateral wall of the rectum; one of these perforated in the perirectal space with development of a local abscess. The presence of M. fortuitum in the lesions was established by detection of mycobacteria in the smear (2 cases) or in the histological section (1 case), and by positive cultures (all cases). All strains were susceptible to aminoglycosides, quinolones (except 2), macrolides and to imipenem. They were resistant to current antituberculous drugs, to tetracycline and to beta-lactamines. Two patients healed, one spontaneously and the other one with antibiotics (amikacin and norfloxacin for 3 months); two patients died, one because of cardiac failure and intercurrent infection and the other one after rectal bleeding. The histopathological pattern of the lesions was pleomorphic: chronic aspecific inflammatory reaction, granulomatous tissue with Langhans cells (1 cas), necrotic abscesses without caseation, intratissular acid-fast bacilli (1 case). The isolation of M. fortuitum in the rectal ulcers has been discussed.