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Biomedical subjects

A R Ronald

Publications and source records attributed to A R Ronald.

224 records · Page 13Linked to original sources
PubMedDate not supplied

Use of an adsorption enzyme immunoassay to evaluate the Haemophilus ducreyi specific and cross-reactive humoral immune response of humans.

Serodiagnosis of chancroid is limited by the cross-reactivity of Haemophilus ducreyi with Haemophilus influenzae and Haemophilus parainfluenzae. This research describes an adsorption enzyme immunoassay (EIA) that assesses the humoral immune response of North Americans and Africans to H. ducreyi. Adsorption effectively removed anti-H. influenzae and anti-H. parainfluenzae antibodies, revealing that North American control sera had no residual anti-H. ducreyi reactivity. However, African control sera still had a residual anti-H. ducreyi response. Assessment of the duration of the humoral immune response in sera from African patients with chancroid showed that the humoral antibodies persisted for up to 8 months after the diagnosis. This may explain the lack of specificity of the adsorption EIA in areas where chancroid is endemic. The detection of the humoral immune response was affected by the strain of H. ducreyi used, with indigent strains being most useful. Using H. ducreyi 35000 for Canadian sera, the sensitivity of the adsorption EIA was 100% and the specificity was 88%. For African sera, H. ducreyi strain R018 was used, and the adsorption EIA had a sensitivity of 81% and a specificity of only 23%. These data reveal that the existing humoral response in a country where chancroid is endemic differs from that in a country where it is not, and that care must be used interpreting unadsorbed humoral immune responses. The adsorption EIA approach may prove useful as an epidemiologic tool for definition of existing (past and present) levels of exposure to H. ducreyi.

Adolescent↗
PubMedDate not supplied

Urethral infection with Haemophilus ducreyi in men.

Carriage of Haemophilus ducreyi has not been adequately investigated in men, and its role in urethritis is unknown. In this study 456 men with H. ducreyi-culture positive genital ulcers were investigated. Among these men, 16 (3.5%) had urethritis. H. ducreyi was isolated from the urethra of nine men (1.9%). Of 57 men who had chancroid but not urethritis, none had H. ducreyi isolated from the urethra. Of 106 patients presenting with only acute urethritis, H. ducreyi was found in one. We conclude that H. ducreyi is responsible for acute urethritis in men, but that it rarely, if ever, can be cultured from the urethra of men with chancroid who do not have symptomatic urethritis.

Adolescent↗
PubMedDate not supplied

Antimicrobial therapy of chancroid: an evaluation of five treatment regimens correlated with in vitro sensitivity.

One hundred fifty-one men with genital ulcer disease were assigned randomly to treatment with one of five oral antimicrobial regimens: (1) sulfadimidine (1 g four times daily for seven days); (2) tetracycline (500 mg four times daily for seven days); (3) trimethoprim-sulfamethoxazole (TMP-SMZ; 160 mg of TMP and 800 mg of SMZ twice daily for seven days); (4) doxycycline (300 mg as a single dose); or (5) TMP-sulfametrole (640 mg of TMP and 3,200 mg of sulfametrole once as a single dose). Haemophilus ducreyi was isolated from 81 (54%) of the men, and 35 strains were available for testing of antimicrobial susceptibility. The TMP-SMZ and TMP-sulfametrole regimens were more effective than sulfadimidine, tetracycline, or single-dose doxycycline in curing ulcers. Only one of 35 strains tested was susceptible to tetracycline (less than or equal to 8 mg/liter), and only ten of 35 strains were susceptible to doxycycline (less than or equal to 4 mg/liter), whereas all were susceptible to trimethoprim (less than or equal to 2 mg/liter). The correlation between in vitro susceptibility and bacteriologic response to the antimicrobial agents requires further investigation. In particular, sulfonamide resistance did not always identify failure to respond to sulfadimidine.

Chancroid↗