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Chancroid and Haemophilus ducreyi
1Sexually Transmitted Diseases Laboratory Program, Center for Infectious Diseases, Atlanta, Georgia 30333.
Insights
Haemophilus ducreyi causes chancroid, a genital ulcerative disease prevalent in Africa and Asia. Diagnosis is challenging due to difficult isolation and limited diagnostic tests, hindering effective treatment and epidemiological studies.
Area of Science:
- Infectious Diseases
- Microbiology
- Bacteriology
Background:
- Haemophilus ducreyi is the primary cause of chancroid, a significant genital ulcerative disease in Africa and Southeast Asia.
- Its prevalence is increasing in the United States, posing a growing public health concern.
- Current diagnostic methods, including culture and serological tests, are often unreliable or difficult to perform.
Purpose of the Study:
- To highlight the challenges in diagnosing Haemophilus ducreyi infections.
- To underscore the limited understanding of H. ducreyi's biology and virulence.
- To emphasize the critical issue of antimicrobial resistance in H. ducreyi.
Main Methods:
- Review of existing literature on Haemophilus ducreyi.
- Analysis of diagnostic limitations for chancroid.
- Examination of antimicrobial resistance patterns and genetic determinants.
Main Results:
- Definitive diagnosis requires H. ducreyi isolation, which is hampered by suboptimal culture media and technical difficulties.
- Limited biochemical activity and phenotypic markers restrict epidemiological strain typing.
- H. ducreyi exhibits concerning antimicrobial resistance, acquiring determinants transferable to other bacteria.
Conclusions:
- There is a critical need for improved diagnostic tools and a deeper understanding of H. ducreyi.
- The organism's limited phenotypic markers and acquired antimicrobial resistance pose significant challenges for disease control.
- Further research is essential to identify virulence factors and develop effective therapeutic strategies.
Abstract:
Haemophilus ducreyi is the causative agent of chancroid, one of the genital ulcerative diseases. H. ducreyi is the major cause of genital ulcer disease in Africa and Southeast Asia and is of increasing concern in the United States. Definitive diagnosis of chancroid requires the isolation and identification of H. ducreyi, but isolation of this organism is difficult and the available medium is not optimal for all strains. Fluorescent antibody and serologic tests are of limited value. In general, our knowledge of this organism is rather limited, and indeed, recent studies have questioned the placement of H. ducreyi in the genus Haemophilus. H. ducreyi has relatively few biochemical activities, and epidemiologic studies are limited because there are limited phenotypic markers available for strain typing. Specific virulence factors of H. ducreyi have yet to be identified. Antimicrobial resistance in H. ducreyi is of special concern, as this organism has acquired both gram-negative and gram-positive resistance determinants. In addition, some of these determinants can be mobilized and transferred to other Haemophilus species or to Neisseria gonorrhoeae.