Efficacy of novel lipid-formulated whole bacterial cell vaccines against Mycobacterium avium subsp paratuberculosis in sheep

Mycobacterium avium subsp. paratuberculosis [MAP], the Causative agent of enteric Johne's disease, incurs significant economic losses to the livestock industry. Prophylactic vaccination can be employed as a control means, however mineral oil-based vaccines Currently in practice have limited efficacy, produce strong antibody responses that confound serological diagnostic testing, and cause severe injection site reactions. In the present study, the safety and efficacy of a commercial mineral oil-adjuvanted vaccine (Gudair (TM)) was compared with novel parenteral-route vaccines in sheep: these comprised live or heat-killed (HK) whole cell preparations of MAP strain 316F, formulated into a food-grade lipid vaccine delivery matrix. Subcutaneous administration of lipid-formulated live or I HK 316F-induced significantly fewer adverse injection site reactions than Gudair (TM); adverse injection site reactions were eliminated altogether by intraperitoneal (i.p.) injection of lipid-formulated live 316F Injections of lipid-formulated 316F-induced significant peripheral blood cell-mediated immune (CMI) responses in the absence of antibody, while Gudair (TM)-induced strong antibody and CMI reactivity. Vaccinated and non-vaccinated control sheep were challenged via oral inoculation of a virulent MAP isolate, and disease progress was monitored for 16 months, followed by necropsy. All vaccine regimes reduced the overall pathological grading of biopsied intestinal tract (IT) tissues; among these, only Gudair (TM) promoted a significant reduction in the incidence of histopathological IT lesions, while only i.p. injection of lipid-formulated live 316F significantly reduced the incidence of gross IT lesions. All lipid-formulated vaccines (but not Gudair (TM)) significantly reduced the incidence of bacteriological culture-confirmed MAP infection. This study identifies a new vaccination strategy against Johne's disease in sheep using conventional MAP vaccine strains formulated in a metabolisable lipid delivery matrix. (C) 2008 Published by Elsevier Ltd

Immunological and molecular characterization of susceptibility in relationship to bacterial strain differences in Mycobacterium avium subsp paratuberculosis infection in the red deer (Cervus elaphus)

Johne's disease (JD) infection, caused by Mycobacterium avium subsp. paratuberculosis, represents a major disease problem in farmed ruminants. Although JD has been well characterized in cattle and sheep, little is known of the infection dynamics or immunological response in deer. In this study, typing of M. avium subsp. paratuberculosis isolates from intestinal lymphatic tissues from 74 JD-infected animals showed that clinical isolates of M. avium subsp. paratuberculosis from New Zealand farmed red deer were exclusively of the bovine strain genotype. The susceptibility of deer to M. avium subsp. paratuberculosis was further investigated by experimental oral-route infection studies using defined isolates of virulent bovine and ovine M. avium subsp. paratuberculosis strains. Oral inoculation with high (109 CFU/animal) or medium (107 CFU/animal) doses of the bovine strain of M. avium subsp. paratuberculosis established 100% infection rates, compared to 69% infection following inoculation with a medium dose of the ovine strain. The high susceptibility of deer to the bovine strain of M. avium subsp. paratuberculosis was confirmed by a 50% infection rate following experimental inoculation with a low dose of bacteria (103 CFU/animal). This study is the first to report experimental M. avium subsp. paratuberculosis infection in red deer, and it outlines the strong infectivity of bovine-strain M. avium subsp. paratuberculosis isolates for cervines

An in vivo comparison of bacillus Calmette–Guérin (BCG) and cytokine-secreting BCG vaccines

A recombinant bacillus Calmette–Guérin (BCG) vaccine has been developed, which constitutively secretes interleukin (IL)-2. Groups of deer were immunized with either normal BCG (Pasteur 1173 P2 strain) or recombinant BCG (rBCG/IL-2) and their immune responses were monitored over 3 months. Animals gained weight over this period and showed no signs of adverse reactions to either vaccine. Lymphocyte transformation responses did not differ significantly between the two groups. No antibody that was specific for BCG was detected in any animal. Intradermal skin-test responses to BCG antigens showed that the rBCG/IL-2 induced a smaller delayed-type hypersensitivity response than the normal BCG. Cytokine transcription was determined by reverse transcription–polymerase chain reaction (RT–PCR). While IL-2 and interferon-γ (IFN-γ) levels did not differ significantly between the two groups, the level of IL-4 was found to be lower in the group given rBCG/IL-2. This resulted in a strong interferon-γ:IL-4 ratio, suggesting a skewing of the immune response towards a Type 1 response. The rate at which the vaccine was eliminated from the host was the same regardless of whether BCG or rBCG was used. At autopsy (3 months after vaccination) 99·99% of the organisms had been eliminated. The small number of organisms isolated from the draining lymph node of animals given rBCG/IL-2 were grown in antibiotic-containing media. They were shown to still contain the shuttle plasmid and to secrete biologically active IL-2, indicating that the plasmid was stably maintained despite the host's immune response and in the absence of antibiotic selection

Isolamento e teste de susceptibilidade a antimicrobianos de bactérias em infecções uterinas de éguas Isolation and antimicrobial susceptibility of bacteria in uterine infections in mares

Foram examinados 206 "swabs" cervicais e uterinos de éguas de várias raças, de diversas regiões do Estado de Minas Gerais, durante o período de 1986 a 1996. Cerca de 164 "swabs" foram positivos para a presença de microrganismos causadores de endometrites. Streptococcus equi subsp. zooepidemicus (25,7%) e Escherichia coli (15,1%) foram os principais agentes infecciosos isolados. Outros microrganismos presentes foram: Staphylococcus aureus (9,2%), Streptococcus alfa-hemolítico (9,2%), Pseudomonas aeruginosa (3,9%), Staphylococcus coagulase negativo (6,3%), Bacillus spp. (1,9%), Rhodococcus equi (3,4%) e Proteus mirabilis (1,5%). As provas de susceptibilidade aos antimicrobianos revelaram que amicacina e gentamicina (70,2%), ampicilina (59,5%) e cloranfenicol (59,5%) foram os antibióticos de maior ação in vitro contra os microrganismos isolados.<br>This study examined 206 cervical and uterine swabs collected from infected mares from herds in the Minas Gerais State, Brazil, from 1986 to 1996. Amongst 164 successful isolations, 25.7% were identified as Streptococcus equi, subsp. zooepidemicus, and 15.1% as Escherichia coli, both considered the most important isolates. Other bacteria found included Staphylococcus aureus (9.2%), Streptococcus alpha-hemolytic (9.2%), Pseudomonas aeruginosa (3.9%), coagulase negative Staphylococcus (6.3%), Bacillus spp. (1.9%), Rhodococcus equi (3.4%) and Proteus mirabilis (1.5%). The antibiotic susceptibility tests revealed amikacin and gentamicin (70.2%), ampicillin and chloramphenicol (59.5%) as the most effective in vitro antibiotics against these microorganisms