Characterization, in vitro susceptibility, and clinical significance of CDC group HB-5 from Rwanda

From June 1984 until July 1988, CDC group HB-5 isolates were recovered from the exudates of genital ulcers in 25 of 675 (3.6%) patients (204 women, 471 men) in Kigali, Rwanda. Among a group of 145 men presenting with urethritis but without genital ulcers, a positive culture for HB-5 of a specimen from the coronal groove of the penis of only 1 man (0.7%) was found. During the same period, the organism was not obtained in cultures of vaginal specimens from 838 women without genital ulcer disease. The main biochemical characteristics of the isolated microorganisms included weak oxidase positivity, catalase negativity, indole positivity, reduction of nitrate to nitrite, acid production from D-glucose and fructose, and H2S production. A total of 75% of the organisms were susceptible to penicillin G. beta-Lactamase production was detected by the chromogenic cephalosporin test in a quarter of the strains. This study confirms that HB-5 can be found in the genital tract. HB-5 was associated with genital ulcer disease in Rwanda. However, its etiologic role in patients with this condition remains unclear.