Swine model of Haemophilus ducreyi infection

Abstract

Haemophilus ducreyi is a strict human pathogen that causes sexually transmitted genital ulcer disease. We infected domestic swine with H. ducreyi 35000, resulting in the development of cutaneous ulcers histologically resembling human chancroid lesions. Intraepidermal lesions progressed from pustules to ulcers containing polymorphonuclear leukocytes and were accompanied by a dermal inflammatory infiltrate containing T cells and macrophages. H. ducreyi was recovered from lesions up to 17 days after inoculation, and pigs did not develop immunity to reinfection with the challenge strain. Features of the model include inoculation through abrasions in the epidermis, ambient housing temperatures for infected pigs, the ability to deliver multiple different inocula to a single host, and the availability of monoclonal antibodies against porcine immune cells permitting immunohistochemical characterization of the host immune response to H. ducreyi infection.

Comparative Genomics of Actinobacillus pleuropneumoniae Serotype 8 Reveals the Importance of Prophages in the Genetic Variability of the Species

“…A. suis is commonly found in swine as tonsil commensal, but in the presence of unknown stimuli, it may invade the bloodstream, causing septicemia and sequelae, such as meningitis and arthritis, and even lead to the death of the host [52]. On the other hand, M. haemolytica is frequently involved in respiratory diseases in cattle [53] while H. ducreyi is a bacterium that causes soft chancre, a sexually transmitted disease in humans, and which has pigs as a model for studying the disease [54,55]. Of the 6 sequences with high similarity and coverage identified in GenBank, only prophage 4 of the M62 strain had significant alignment correspondence with the phage sequence already described in the literature.…”

Characterization of a Haemophilus ducreyi Mutant Deficient in Expression of Cytolethal Distending Toxin

“…The organism is apparently not able to invade intact skin (64), and it is assumed that microabrasions sustained during sexual activity permit entry of the organism beneath the skin surface. The introduction of a number of new model systems for studying the interaction of H. ducreyi with host cells both in vitro and in vivo (8,23,24,33,68,69,71) has facilitated studies intended to identify virulence factors of this pathogen. In the past few years, a number of H. ducreyi gene products have been postulated to be involved directly or indirectly in virulence expression (7, 9-11, 17-19, 34, 37, 38, 48, 49, 59, 60, 66, 73), including at least two proteins which have cytotoxic activity.…”

Chancroid: contemporary appraisal

“…Several useful animal models, rabbits, primates, and pigs, as well as human volunteers have been employed for defining the characteristics of this fastidious bacteria. [50][51][52][53][54] Culture of the organism in vitro can be carried out on enriched media, such as a medium containing agar, cysteine, dextrose and defibrigenated rabbits serum incubated at 35 ° C. Pillay et al . 55 compared seven different agar-based media to determine the optimal primary isolation of H. ducreyi .…”