Renato Varges

Interference of intradermal tuberculin tests on the serodiagnosis of paratuberculosis in cattle

In this experiment 63 animals from a paratuberculosis (PTB) and tuberculosis-free herd were tested by Intradermal Tuberculin Tests (ITT) and blood samples were collected before PPD inoculation and on days 3, 15, 30, 60 and 90 post-inoculation (p.i.). Sera were tested for PTB-specific antibodies by ELISA-PPA and confirmed by a commercial ELISA. Three (4.76%) animals were positive by ELISA-PPA and five (7.93%) in the commercial ELISA, between days 30 and 90 p.i. These results suggest that ITT can interfere in the reliability of ELISAs and that serological testing for PTB should be avoided for 90d after PPD inoculation.

Occurrence of false-positive results in three paratuberculosis - ELISAs performed in a tuberculous herd

The interference of bovine tuberculosis (TB) on the efficacy of paratuberculosis (PTB) diagnostic tests has been evaluated. A group of 32 tuberculous cows identified by both intradermal tests and gamma-interferon assay, 16 of them confirmed by the recovery of M.bovis from tissues, was tested by three different PTB- ELISAs, being two commercials and one in-house. The rest of the adult animals of the herds, totalizing 216 TB-negative animals, were also tested as a control group. Fecal culture for PTB was negative in all animals, but seven (21.8%) tuberculous cows produced false-positive reactions when tested by various PTB-ELISAs, leading to a misdiagnosis. Tuberculosis impairs the specificity of serological tests for paratuberculosis diagnosis and should be considered for the reliability of PTB control programs.

Antimicrobial susceptibility of Staphylococci isolated from naturally occurring canine external ocular diseases

OBJECTIVE The purpose of this study was to describe the species distribution and antimicrobial susceptibility patterns of Staphylococci isolated from naturally occurring canine ocular diseases. SAMPLES AND PROCEDURES: Samples obtained from 68 dogs with signs of external eye disease were processed for isolation of bacteria of the genus Staphylococcus sp. Isolates were identified by biochemical reactions and tested for susceptibility to 11 antimicrobials of six classes. RESULTS Forty (58.8%) samples yielded Staphylococcus sp. in pure culture. Coagulase-positive Staphylococci were most common and Staphylococcus intermedius was the most frequent (45%) species, followed by S. aureus (22.5%) and the coagulase-negative species S. epidermidis (20%), and S. simulans (12.5%). Resistance to at least one drug was observed in 92.5% of the isolates, and multidrug resistance was a common finding (72.5%). The most effective drugs against Staphylococcus strains isolated from extra-ocular canine ocular diseases were ceftiofur and cefalexin. CONCLUSION This study highlights the presence of Staphylococcus sp. genus in naturally occurring extra-ocular canine ocular disease and the emergence of resistant strains to common antimicrobial drugs. It also emphasizes the need for bacterial culture with species identification and susceptibility testing in order to choose the appropriate antimicrobial therapy.

In vitro antimicrobial susceptibility of staphylococci isolated from canine pyoderma in Rio de Janeiro, Brazil

The study aimed to determine the etiology and antimicrobial resistance of staphylococci isolated from canine pyoderma. Samples were obtained from dogs with pyoderma and isolates were identified by biochemical reactions and tested for susceptibility to 15 antimicrobials. Thirty nine staphylococci isolates were obtained, and S. pseudintermedius was the most frequent (47.4%). All isolates showed resistance to at least one drug and 77.1% were multiresistant. The most effective drug was oxacillin. The study reports the alarming antimicrobial resistance of Staphylococcus isolated from canine pyoderma samples.

Alterações na bioquímica hepática em cães com leptospirose aguda determinada por amostras do sorogrupo Icterohaemorrhagiae

One hundred and twenty serum samples obtained from dogs with specific titres (≥100) against Leptospira spp. serovar Icterohaemorrhagiae were tested in order to determine the enzymatic activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), gamaglutamyltransferase (GGT), as well as of the total cholesterol, triglycerides, total protein, albumin, globulins and total, direct and indirect bilirubins serum concentrations. Thirty four animals free from clinical signs with the same age of the tested group were used as control group and submitted to the same biochemical tests. The animals with titres ≥200 showed increased ALP activity and greater direct bilirubin concentration when compared to the control group and also to the group of dogs with titres <200 (P<0.05). A clear correlation was observed between hepatic damage, without hepatocellular necrosis, and specific seroreactivity for leptospirosis caused by serogroup Icterohaemorrhagiae.

Níveis séricos de uréia e creatinina em cães com leptospirose aguda determinada por amostras do sorogrupo Icterohaemorrhagiae

Foram testadas 120 amostras sericas de caes com titulos (³100) perante Icterohaemorrhagiae para a determinacao dos niveis sericos de ureia e de creatinina. Os animais com titulos ³800 apresentaram dosagens de ureia bastante superiores aos valores de referencia e os com titulos ³200 e £400 apresentaram valores de ureia significativamente menores (P<0,05) do que os anteriores, porem ainda acima dos valores de referencia. As amostras com titulos menores que 200 apresentaram dosagens de ureia significativamente menores (P<0,05) do que os observados nos outros grupos e dentro dos valores de referencia. No que se refere a dosagem de creatinina serica, verificou-se que apenas os animais com titulos ³800 apresentaram dosagens acima do padrao normal. Observou-se uma clara correlacao entre dano renal e a sororreatividade especifica para leptospirose.

Ocorrência de aglutininas antileptospiras em suínos de criação intensiva no estado do Rio de Janeiro - RJ

Foram examinadas 351 amostras de soros sanguineos de matrizes de suinos oriundos de 18 propriedades de exploracaointensiva localizadas em dez municipios do estado do Rio de Janeiro. O teste sorologico foi realizado pela tecnica desoroaglutinacao microscopica (MAT) utilizando-se antigenos vivos dos serovares pomona, wolffi, bratislava, hardjo, tarassovi,copenhageni, icterohaemorrhagiae e bataviae. Foram observadas 232 (66,09%) reacoes positivas. Das 18 propriedadesexaminadas, 16 (88,89%) apresentaram indices de reatividade. O serovar ictetohaemorrhagiae apresentou o maior percentualde observacoes com 28,48% de ocorrencias, seguido de pomona com 11 ,97%, copenhageni 9,69%, tarassovi com 6,55%,hardjo com 4,56%, bratis/ava com 2,56% e wolffi, com 2,28%. Reacoes para o serovar bataviae nao foram evidenciadas emnenhuma propriedade pesquisada. As provas sorologicas demonstram a alta ocorrencia de sororreatividade para leptospirasnas propriedades, com alteracao na frequencia de serovares anteriormente descritos como os prevalentes na suinocultura.