Results of culture form colonoscopically obtained specimens for bacteria and fungi in HIV-infected patients with diarrhea.

Background: The aim of our study was to determine the diagnostic yield of culture for bacteria and fungi from colonic biopsy specimens in 290 consecutive HIV-infected patients with diarrhea.

Methods: During each colonoscopy, three biopsy specimens were homogenized and cultured on media for Salmonella and Shigella and for Campylobacter and Yersinia, on Loewenstein medium and on Sabouraud medium.

Results: Cultures were found positive for one (n = 32) or two (n = 5) infectious agents in 37 cases, i.e., in 12.8% of the patients. Bacteria were isolated in 24 cases, and identified as Campylobacter jejunl-coli (n = 14), Salmonella (n = 2), Shigella (n = 1), or Pseudomonas aeruginosa (n = 7). Among the 14 patients with C. jejuni-coli intestinal infection, 11 had normal-appearing mucosa at colonoscopy, and 3 had a concomitant stool culture negative for Campylobacter. Mycobacterial cultures were positive for Mycobacterium avium intracellulare in 6 patients, who were already known as having a disseminated M. avium intracellulare infection from positive blood cultures. Fungal cultures were positive for Candida in 10 cases, without clear clinical significance.

Conclusions: The overall yield of culture for bacterial pathogens from colonic tissue in HIV-infected patients with diarrhea is low, but some individual cases of C. jejuni-coli infections may be detected from colonic tissue culture and not diagnosed by concomitant stool culture.