PCR-RFLP of outer membrane proteins gene of Dichelobacter nodosus: a new tool in the epidemiology of footrot.
Currently only phenotypic epidemiological markers, serogrouping and virulence testing of Dichelobacter nodosus, are available for investigating footrot outbreaks in small ruminants. These methods have limitations in tracing the source of infection. In this study, a genotypic marker, PCR-RFLP of outer membrane protein gene, was used to characterize D. nodosus. The technique was evaluated in a controlled experiment involving two strains of bacteria. PCR-RFLP was found to be highly specific in differentiating isolates obtained from recipient animals infected with different strains. Subsequently, this technique was used to characterize isolates obtained from field cases of footrot in Nepal. A total of 11 patterns was recognized among 66 Nepalese D. nodosus isolates representing four different serogroups. PCR-RFLP also discriminated isolates with similar phenotypic characteristics. However, all isolates which, phenotypically, were virulent were represented by only two patterns irrespective of their serogroups. It is suggested that PCR-RFLP described here could be a useful epidemiological marker in the study of footrot. (+info)
Determination of some in vitro growth requirements of Bacteroides nodosus.
Physical and nutritional factors required for growth of Bacteroides nodosus isolates from ovine foot-rot lesions were examined. Simplified anaerobic culture techniques were devised utilizing a fully soluble, autoclavable, liquid medium (TAS) which contained proteose-peptone, yeast and meat extracts and certain other essential compounds required to promote prompt and serially transferrable growth of cultures from small inocula. The latter included Trypticase, arginine, a reducing agent (most suitably thioglycollic acid) and CO2; serine and Mg2+ markedly increased growth yields. Trypticase could not be replaced by a commercial preparation of acid-hydrolysed casein; other forms of hydrolysed protein gave delayed and inconsistent growth. Maximum growth of cultures required concentrations of 0-02 to 0-35 M-arginine, which could not be replaced by glutamic acid, citrulline or ornithine. Exogenous carbohydrate compounds were not required. The temperature range for optimum growth of cultures was 37 to 39 degrees C, and anaerobic culture conditions were essential for growth and the production of B. nodosus organisms of normal morphology. Solidified TAS media for the isolation and maintenance of B. nodosus cultures were also devised. (+info)
Isolation and characterisation of a novel spirochaete from severe virulent ovine foot rot.
A novel spirochaete was isolated from a case of severe virulent ovine foot rot (SVOFR) by immunomagnetic separation with beads coated with polyclonal anti-treponemal antisera and prolonged anaerobic broth culture. The as yet unnamed treponeme differs considerably from the only other spirochaete isolated from ovine foot rot as regards morphology, enzymic profile and 16S rDNA sequence. On the basis of 16S rDNA, it was most closely related to another unnamed spirochaete isolated from cases of bovine digital dermatitis in the USA, raising the possibility of cross-species transmission. Further information is required to establish this novel ovine spirochaete as the cause of SVOFR. (+info)
Susceptibilities of anaerobic bacteria isolated from animals with ovine foot rot to 28 antimicrobial agents.
The agar dilution method was used to determine the inhibitory activities of 28 antimicrobial agents against 35 strains of the genus Peptostreptococcus, 4 strains of the species Peptococcus niger, 20 strains of the species Megasphaera elsdenii, 7 strains from the species Acidaminococcus fermentans, 8 strains of the genus Clostridium, 11 strains of the genus Eubacterium, and 1 strain of the species Propionibacterium acidipropionici, all of which were isolated from 125 clinical cases of ovine foot rot between January 1987 and December 1988. The three unreidopenicillins studied proved to be the most active antimicrobial agents, with a high percentage of strains being susceptible at a concentration of 64 micrograms/ml. Penicillin G, ampicillin, and the three cephalosporins studied also had good activity. Fosfomycin showed a high degree of activity among the 116 anaerobic bacteria tested. (+info)
Recent footrot outbreak in Debrezeit swine farm, central Ethiopia.
An outbreak of footrot has occurred in Debrezeit swine farm that is located 44 km south east of the capital. Among 24 pigs, 75% showed lameness, hot, painful and swollen feet, hemorrhagic bruising of the coronary band, heel erosion, sole ulcers and separation of skin from hoof on hind limbs. Bacteriological examination of the specimen from the affected limbs has shown the involvement of Staphylococcus, Streptococcus and Dichelobacter nodosus. The overt clinical lameness and inability to stand or mount can cause reduced reproductive performance. This preliminary finding thus warrants further epidemiological investigation. (+info)
Efficacy of vaccination against Fusobacterium necrophorum infection for control of liver abscesses and footrot in feedlot cattle in western Canada.
A randomized and blinded field trial was carried out to evaluate the efficacy of a Fusobacterium necrophorum bacterin for control of liver abscesses and footrot under commercial feedlot conditions in western Canada. Half of the vaccinated and half of the unvaccinated control animals had ad libitum access to a forage-based (ALF) growing diet. The other half of each group was limit-fed a grain-based (LFG) growing diet. The overall prevalence of A and A+ liver abscesses in this trial was 16.7%. A strong association was found between diet group and presence of A or A+ liver abscessation at slaughter. Diet group modified the effect of vaccination on the prevalence of liver abscesses at slaughter, and on the incidence of footrot during the feeding period. The odds that a vaccinated animal in the ALF group would have an A or A+ liver abscess at slaughter were less than 1/3 the odds that an unvaccinated animal in the same diet group would have an A or A+ liver abscess at slaughter (OR = 0.27, [95% CI: 0.07 to 1.02], P = 0.05). The overall incidence of footrot in this trial was 6.5%. The odds that a vaccinated animal in the ALF group would be treated for footrot were less than 1/5 the odds that an unvaccinated animal in the same group would be treated for foot-rot (OR = 0.18, [95% CI: 0.04 to 0.82], P = 0.03). Within the LFG group there were no differences between vaccinated and unvaccinated animals in the odds of an animal being treated for footrot, or in the odds of having an A or A+ liver abscess score at slaughter. This trial suggests that vaccination against F. necrophorum infection may have applications to decrease the prevalence of severe liver abscesses at slaughter and decrease footrot treatments in certain diet situations. (+info)
Elastolytic activity of Bacteroides nodosus isolated from sheep and goats with foot rot.
The elastolytic activities of 82 Bacteroides nodosus strains were studied. Two substrates, insoluble elastin and soluble elastin, were used for this purpose. Roughly 15% of the strains which did not digest insoluble elastin were elastolytic with soluble elastin, the latter providing greater sensitivity, speed, and objectivity than its insoluble counterpart. (+info)
Twitching motility is essential for virulence in Dichelobacter nodosus.