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ABSTRACT The aim of this study was to diagnose the causative agent of carp (Cyprinidae) mortality in an artificial lake used for recreation in Jaraguá do Sul, state of Santa Catarina, in February 2018. The fish showed symptoms, including skin ulceration, hemorrhages on the surface of the body, loss of scale and increased mucus production. Through the proteomic profile, using the MALDI-TOF technique, three bacterial isolates were identified as Aeromonas veronii, A. hydrophila and Citrobacter freundii. In addition, in the mucus scraping, a large number of the ectoparasite Argulus was observed. A blood collection was carried out to verify the hematological indices of the animals and a decrease in the the hematocrit value, erythrocyte count, and differential leukocyte count was observed. These findings indicate that Argulus infection increases the carp’s susceptibility to bacterial diseases and contributes to the suppression of the innate immune system and consequent increase in mortality.

Caracterizaram-se as populações bacterianas isoladas de três sistemas de cultivo de tilápias, sem utilização prévia de antimicrobianos. No sistema 1 usou-se tanque de alvenaria com arraçoamento, no sistema 2, tanque de terra com arraçoamento e no sistema 3, tanque de terra com adubação orgânica. Posteriormente, foi verificado o perfil qualitativo de resistência a antimicrobianos de 98 amostras bacterianas. Membros da família Vibrionaceae predominaram nos três sistemas analisados. Observou-se elevado número de bactérias resistentes principalmente à ampicilina e à eritromicina. Bactérias resistentes à norfloxacina e à gentamicina não foram freqüentes e cerca de 50% das amostras dos isolados bacterianos foram resistentes à tetraciclina. Dentre as amostras testadas, 96% apresentaram resistência simultânea a dois ou mais antimicrobianos (MAR>0,2). O índice MAR médio para os três sistemas de criação foi 0,4, e foram mesmo considerados fontes de risco para disseminação de bactérias resistentes.Bacterial populations from different tilapia culture system with no antimicrobial use were characterized. Concret pond and commercial feed, land pond and commercial feed, and land pond and animal manure were used in systems I, II and III, respectively. Ninety-eight bacterial strains were subjected to sensitivity testing. Members of Vibrionaceae were the most prevalent in all systems analysed. The most bacterial strains were resistant to ampicillin and erithromicin, but resistance to norfloxacin and gentamicin were uncommon. A half to bacterial isolates was resistant to tetracycline. From the 98 bacterial isolates, 96% were resistant to two or more antimicrobials. The multiple antimicrobial resistance index was determined and it was similar for all systems analyzed (Mar= 0.4), indicating a high risk source for multiple antibiotic resistance.

A bacterin from enterotoxigenic Escherichia coli (ETEC), containing fimbriae K99 and F41, was produced and its capacity to induce anti-K99 and anti-F41 antibodies in colostrum of vaccinated cows and in calf serum, and the persistence of these antibodies in neonates were determined. Three experiments were performed on two commercial farms. In all experiments animals were allotted randomly to the blocks, each block consisting of two pregnant females (a vaccinated one and a control one) and their respective calves. In experiment A (farm 1), comprised of 18 blocks, the animals received a vaccine dose 30 days before delivery. In experiment B (farm 1), consisted of 26 blocks, the animals received two vaccine doses (60 and 30 days before delivery). In experiment C (farm 2), consisted of 22 blocks, the animals received two vaccine doses (60 and 30 days before delivery). In experiments A and B pregnant cows and heifers were used and colostrum and serum from 24- to 36-hour-old calves were collected. In experiment C, pregnant embryo-recipient heifers were used and colostrum and sera from calves at 7, 14, 28 and 42 days of age were collected. Anti-K99 and anti-F41 antibodies were detected by ELISA using purified K99 and F41 fimbrial antigens. In experiment A no difference between treated and control groups was observed for the concentration of anti-K99 and anti-F41 antibodies in colostrum and calf serum. In experiment B a difference (PProduziu-se uma bacterina de Escherichia coli enterotoxigênica (ETEC) contendo as fímbrias K99 e F41 e avaliaram-se a capacidade de indução de anticorpos anti-K99 e anti F-41 no colostro de vacas vacinadas e no soro de bezerros e a persistência dos anticorpos nos neonatos. Três experimentos foram realizados em duas fazendas comerciais. Os animais foram aleatoriamente alocados em blocos, de duas fêmeas prenhes (uma vacinada e outra controle) e seus respectivos bezerros. No experimento A (fazenda 1), com 18 blocos, os animais receberam uma dose da vacina, 30 dias antes do parto. No experimento B (fazenda 1), com 26 blocos, os animais receberam duas doses de vacina, aos 60 e 30 dias antes do parto. No experimento C (fazenda 2), com 22 blocos, os animais receberam o mesmo esquema de vacinação do experimento B. Nos experimentos A e B foram coletados colostro das parturientes e soro dos bezerros entre 24 e 36 horas de vida. No experimento C, foram usadas novilhas receptoras de embriões e coletados colostro e soro dos bezerros aos 7, 14, 28 e 42 dias de idade. Anticorpos anti-K99 e anti-F41 foram detectados por ELISA utilizando antígenos K99 e F41 purificados. No experimento A não foi observada diferença entre o grupo vacinado e o controle quanto à detecção de anticorpos. No experimento B foi observada diferença (P

Streptococcus agalactiae was isolated from cultured tilapia in Brasil. All isolates reacted similarly in API 20 STREP system (bioMerieux, France) and Slidex strepto grouping Latex Aglutination test (bioMerieux, France). Bacterial isolates were submitted to the disc diffusion technique for the antimicrobial susceptibility test. Among nine tested drugs S. agalactiae samples were resistant to three-neomicin, nalidixic acid and gentamicin.