AI Article Synopsis
- Haemophilus ducreyi requires heme from human hosts for infection, utilizing TonB-dependent transporters, with HgbA being essential for early infection stages.
- Active immunization with the HgbA protein provides complete protection in pig models of chancroid, indicating its potential as a vaccine.
- Passive immunization using anti-nHgbA serum offers some protection against related strains, showing that antibodies can block heme acquisition but do not kill the bacteria directly.
Article Abstract
Haemophilus ducreyi, the etiologic agent of chancroid, has an obligate requirement for heme. Heme is acquired by H. ducreyi from its human host via TonB-dependent transporters expressed at its bacterial surface. Of 3 TonB-dependent transporters encoded in the genome of H. ducreyi, only the hemoglobin receptor, HgbA, is required to establish infection during the early stages of the experimental human model of chancroid. Active immunization with a native preparation of HgbA (nHgbA) confers complete protection in the experimental swine model of chancroid, using either Freund's or monophosphoryl lipid A as adjuvants. To determine if transfer of anti-nHgbA serum is sufficient to confer protection, a passive immunization experiment using pooled nHgbA antiserum was conducted in the experimental swine model of chancroid. Pigs receiving this pooled nHgbA antiserum were protected from a homologous, but not a heterologous, challenge. Passively transferred polyclonal antibodies elicited to nHgbA bound the surface of H. ducreyi and partially blocked hemoglobin binding by nHgbA, but were not bactericidal. Taken together, these data suggest that the humoral immune response to the HgbA vaccine is protective against an H. ducreyi infection, possibly by preventing acquisition of the essential nutrient heme.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3147553 | PMC |
| http://dx.doi.org/10.1128/IAI.00017-11 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Infections caused by one organism, two stories.
Clin Microbiol Rev
December 2024
Department of Medicine, Division of Infectious Diseases, Indiana University School of Medicine, Indianapolis, Indiana, USA.
Article Synopsis
- Chancroid is a sexually transmitted infection that causes painful genital ulcers and is now linked to non-sexually transmitted skin ulcers in children, particularly in areas where yaws is common.! -
- The review analyzes the differences between genital and cutaneous ulcer strains, their clinical features, diagnosis, and treatment, while highlighting the decline of genital ulcers compared to the persistence of skin ulcers.! -
- Effective management strategies include targeted treatment for at-risk populations and addressing environmental factors to eliminate cutaneous ulcers in children, with a focus on hygiene and identifying additional infection reservoirs.!
Transmission of viable Haemophilus ducreyi by Musca domestica.
PLoS Negl Trop Dis
May 2024
Department of Biology, Allegheny College, Meadville, Pennsylvania, United States of America.
Article Synopsis
- Haemophilus ducreyi, initially known for causing chancroid, has recently been linked to skin ulcers in children from certain regions, with its transmission mechanisms still largely unclear.
- Recent studies suggest that local flies may play a role in transmitting H. ducreyi, particularly in South Pacific and West African areas, with detection of the bacteria's DNA on these insects.
- A study using common house flies demonstrated that a significant percentage (86.11%) could transmit viable H. ducreyi, establishing flies as potential vectors, thereby highlighting the need to further investigate insect involvement in such diseases.
A strain lacking the iron transport system is virulent in human volunteers.
Infect Immun
June 2024
Department of Microbiology and Immunology, Indiana University School of Medicine, Indiana University, Indianapolis, Indiana, USA.
Article Synopsis
- Chancroid, a genital ulcer disease causing painful skin ulcers, is linked to a bacterium that uses a specific receptor, HgbA, to acquire heme from hosts, crucial for its disease progression.
- The study involved creating a mutant strain (35000HPΔΔ) that showed growth issues when using human hemoglobin for iron; however, trials with human volunteers showed both the mutant and the parent strain produced similar skin reactions, indicating that the YfeABCD transporter isn't essential for the bacteria's virulence.
- The research suggests that despite the deletion of the YfeABCD system, the bacteria can rely on alternative transport systems like HbpA and others to manage heme transport, highlighting the redundancy of vir
Prevalence and risk factors associated with Haemophilus ducreyi cutaneous ulcers in Cameroon.
PLoS Negl Trop Dis
December 2023
Centre Pasteur du Cameroun, Yaounde, Cameroon.
Article Synopsis
- * Conducted in Cameroon, the research included 443 participants, revealing a 30.3% prevalence of HD in ulcers and 8.6% in asymptomatic individuals, while Treponema pallidum (TP) was found at a lower rate of 5.2%.
- * Risk factors included gender parity in HD ulcer cases and physical proximity to confirmed cases, with findings indicating that HD is the most common cause of skin ulcers in the studied areas, warranting further research into asymptomatic carriage and disease transmission. *
Haemophilus ducreyi Infection Induces Oxidative Stress, Central Metabolic Changes, and a Mixed Pro- and Anti-inflammatory Environment in the Human Host.
mBio
December 2022
Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, USA.
Article Synopsis
- The study investigates host-bacterial interactions during human infections, focusing on the bacterium Haemophilus ducreyi, which causes skin ulcers and chancroid.
- A human challenge model was developed where healthy volunteers were infected to observe interactions in pustules through transcriptomics and metabolomics analysis.
- The research identified significant changes in gene expressions and metabolomic profiles, revealing a complex environment that both supports and limits the growth of H. ducreyi in infected individuals.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!