Survivability of Mycobacterium bovis on salt and salt-mineral blocks fed to cattle.

OBJECTIVE To determine the survivability of Mycobacterium bovis on salt and salt-mineral blocks in typical weather conditions in Michigan over two 12-day periods at the height of summer and winter. SAMPLE 4 salt (NaCl) and 4 salt-mineral blocks inoculated with pure cultures of a strain of M bovis currently circulating in Michigan livestock and wildlife. PROCEDURES In the summer and again in the winter, inoculated blocks were placed in secured outdoor facilities where equal numbers of each block type (2/type/season) were exposed to shade or sunlight.

Comparison of PCR versus culture for detection of Mycobacterium bovis after experimental inoculation of various matrices held under environmental conditions for extended periods.

The purpose of this study was to compare the performance of a molecular detection technique (nested PCR) with that of mycobacterial culture in the detection of Mycobacterium bovis DNA in a set of 687 samples of experimentally inoculated environmental substrates (hay, soil, corn, water) exposed to natural weather conditions in Michigan. Four replicates of each substrate were used; half were autoclaved for sterilization, all were inoculated with 50,000 CFU of M. bovis isolated from Michigan livestock, and all were placed in outdoor enclosures, with half under shade and the other half exposed to direct sunlight.

Clinical features and risk factors for development of urinary tract infections in cats.

The clinical and diagnostic features of 155 cats with urinary tract infection (UTI) and 186 controls with negative urine culture/s were characterized retrospectively (signalment, clinical signs, urinalysis, urine culture, concurrent diseases, lower urinary tract diagnostic/therapeutic procedures). Multivariable logistic regression was used to identify risk factors associated with UTI. Cats of all ages were affected by UTI with no sex/breed predisposition.

A Study of the Persistence of Mycobacterium bovis in the Environment under Natural Weather Conditions in Michigan, USA.

Reisolation of Mycobacterium bovis from inoculated substrates was used to follow the persistence of viable M. bovis bacteria exposed to natural weather conditions over a 12-month period. Environmental factors were recorded continuously, and factors affecting M.

Use of the intradermal tuberculin test in a herd of captive elk (Cervus elaphus nelsoni) naturally infected with Mycobacterium bovis.

In the United States, tuberculosis of captive cervids, caused by Mycobacterium bovis, attracted attention in 1991 when investigations, prompted by the identification of a tuberculous elk (Cervus elaphus nelsoni) of U.S. origin exported to Canada, revealed tuberculosis in 10 different elk herds in 8 different states.

Proliferation of Streptococcus zooepidemicus and Pseudomonas aeruginosa within a simulated subpalpebral lavage flushed with equine serum.

Objective: To evaluate whether equine serum administered via a simulated subpalpebral lavage system (SPL) supports proliferation of Streptococcus zooepidemicus or Pseudomonas aeruginosa within the tubing.

Procedures: A sterile i.v.

Changes in multidrug resistance of enteric bacteria following an intervention to reduce antimicrobial resistance in dairy calves.

An intervention study was conducted to determine whether discontinuing the feeding of milk replacer medicated with oxytetracycline and neomycin to preweaned calves reduced antimicrobial resistance in Salmonella, Campylobacter, and Escherichia coli bacteria. Results demonstrated that the intervention did reduce multidrug resistance in these bacteria but that other factors also influenced multidrug resistance.

Minimum inhibitory concentration and postantibiotic effect of amikacin for equine isolates of methicillin-resistant Staphylococcus aureus in vitro.

Objective: To report the minimum inhibitory concentration (MIC) of amikacin sulfate for equine clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) and characterize the initial kill and duration of the postantibiotic effect (PAE) for selected strains.

Study Design: Experimental study.

Methods: Isolates of MRSA (n=35) had their amikacin MIC determined using the E-test agar diffusion method.

Changes in tetracycline susceptibility of enteric bacteria following switching to nonmedicated milk replacer for dairy calves.

A randomized intervention study was conducted to determine if discontinuing use of calf milk replacer medicated with oxytetracycline results in increased tetracycline susceptibility in Salmonella and Campylobacter spp. and Escherichia coli in dairy calves over a 12-month period. Dairy herds with enteric bacteria with known low tetracycline susceptibility were enrolled for the study.

Experimental inoculation of meadow voles (Microtus pennsylvanicus), house mice (Mus musculus), and Norway rats (Rattus norvegicus) with Mycobacterium bovis.

Mycobacterium bovis has a wide host range that includes several wildlife species, and this can hamper attempts to eradicate bovine tuberculosis from livestock. The purpose of this study was to determine if common rodent species, namely meadow voles (Microtus pennsylvanicus), house mice (Mus musculus), and Norway rats (Rattus norvegicus), that inhabit the bovine tuberculosis endemic area of Michigan, can be experimentally infected with M. bovis.

Prevalence of serum antibodies against six Leptospira serovars in healthy dogs.

Objective: To determine the prevalence of antibodies against 6 Leptospira serovars and determine risk factors associated with positive Leptospira titers in healthy client-owned dogs in Michigan.

Design: Cross-sectional study.

Animals: 1,241 healthy dogs at least 4 months of age.

Experimental canine leptospirosis caused by Leptospira interrogans serovars pomona and bratislava.

Objective: To evaluate gross, histopathologic, and serum biochemical findings caused by Leptospira interrogans serovars pomona and bratislava inoculated in dogs.

Animals: Twenty-seven 8-week-old female Beagles.

Procedure: Dogs were randomly assigned to challenge or control groups.

Effects of positive results for Mycobacterium avium subsp paratuberculosis as determined by microbial culture of feces or antibody ELISA on results of caudal fold tuberculin test and interferon-gamma assay for tuberculosis in cattle.

Objective: To determine whether cattle testing positive for Mycobacterium avium subsp paratuberculosis as determined by microbial culture of feces or antibody ELISA were more likely to have false-positive responses on the caudal fold tuberculin (CFT) test or interferon-gamma (IFN-gamma) assay for Mycobacterium bovis than cattle testing negative for M paratuberculosis.

Animals: 1043 cattle from 10 herds in Michigan.

Procedure: Feces and blood samples for plasma were collected from cattle > or =24 months old on the day the CFT test was read.

Clinical and pathologic comparison of acute leptospirosis in dogs caused by two strains of Leptospira kirschneri serovar grippotyphosa.

Objective: To develop a method for inducing acute leptospirosis in dogs.

Animals: 31 nine-week-old female Beagles.

Procedure: Beagles were randomly assigned to 2 inoculation groups or a control group.

Pathogenic Leptospira species express surface-exposed proteins belonging to the bacterial immunoglobulin superfamily.

Proteins with bacterial immunoglobulin-like (Big) domains, such as the Yersinia pseudotuberculosis invasin and Escherichia coli intimin, are surface-expressed proteins that mediate host mammalian cell invasion or attachment. Here, we report the identification and characterization of a new family of Big domain proteins, referred to as Lig (leptospiral Ig-like) proteins, in pathogenic Leptospira. Screening of L.

An improved immunohistochemical diagnostic technique for canine leptospirosis using antileptospiral antibodies on renal tissue.

The purpose of this study was to compare the immunoreactivity in canine renal tissues stained with antisera specific for 3 leptospiral antigens and those processed with traditional staining methods. In addition, immunoglobulin staining was done on tissues with immunoreactivity to leptospiral antigens. Formalin-fixed renal sections from 12 dogs with chronic interstitial nephritis suspected or proven to have leptospirosis (6 dogs with silver-stained leptospires and 6 dogs in which silver-stained leptospires were not detected) were used.

Evaluation of type 1 immune response in naïve and vaccinated animals following challenge with Leptospira borgpetersenii serovar Hardjo: involvement of WC1(+) gammadelta and CD4 T cells.

Organisms within the Hardjo serovar of Leptospira species are harbored in cattle throughout the world, causing abortion in pregnant animals as well as being shed in the urine, thereby providing sources of zoonotic infection for humans. We recently showed that sterile immunity in vaccinated cattle is associated with induction of a type 1 (Th1) cell-mediated immune response. Here naïve and previously vaccinated pregnant cattle were challenged with a virulent strain of serovar Hardjo and subsequently evaluated for expression of a type 1 immune response.

Outbreak of leptospirosis among triathlon participants and community residents in Springfield, Illinois, 1998.

We investigated an outbreak of leptospirosis among athletes and community residents after a triathlon was held in Springfield, Illinois. A telephone survey was conducted to collect clinical information and data on possible risk factors, community surveillance was established, and animal specimens and lake water samples were collected to determine the source of the leptospiral contamination. A total of 834 of 876 triathletes were contacted; 98 (12%) reported being ill.

Novel 45-kilodalton leptospiral protein that is processed to a 31-kilodalton growth-phase-regulated peripheral membrane protein.

Leptospiral protein antigens are of interest as potential virulence factors and as candidate serodiagnostic and immunoprotective reagents. We identified leptospiral protein antigens by screening a genomic expression library with serum from a rabbit hyperimmunized with formalin-killed, virulent Leptospira kirschneri serovar grippotyphosa. Genes expressing known outer membrane lipoproteins LipL32 and LipL41, the heat shock protein GroEL, and the alpha, beta, and beta' subunits of RNA polymerase were isolated from the library.