Characterization of Aeromonas Isolates from Ornamental Fish: Species, Virulence Genes, and Antimicrobial Susceptibility.

This study aimed to characterize 300 Aeromonas spp. strains isolated from 123 ornamental fish of 32 different species presenting with septicemia, skin lesions, and/or eye lesions. Within the 300 strains, 53.0% were identified as A. veronii, 41.3% as A. hydrophila, and 5.7% as A. caviae. Among the six virulence genes investigated, the most frequent were act (90.3%) and aer (79.3%). More than 50% of A. hydrophila strains were positive for all the studied genes. A total of 30 virulence profiles were identified, with the five main profiles identified comprising 75% of strains. Only five strains were negative for all genes and were identified as A. caviae and A. veronii. The antimicrobial susceptibility profile was performed for 234 strains, with sulfonamides presenting more than 50% of the resistance rates. Susceptibility was observed mainly for cephalosporins, aminoglycosides, chloramphenicol and piperacillin-tazobactam. Multidrug resistance was detected in 82.5% of the studied strains, including A. caviae with 100% multidrug resistance, and A. hydrophila with 90.9% multidrug resistance. The SE-AFLP analysis resulted in 66 genotypes of A. hydrophila, 118 genotypes of A. veronii, and 14 genotypes of A. caviae, demonstrating the greater heterogeneity of A. veronii and A. caviae. However, no direct correlation was observed between the genotypes and the strains' origins or virulence and resistance profiles.

Main bacterial species causing clinical disease in ornamental freshwater fish in Brazil.

Bacterial diseases are common in ornamental fish, more frequently associated with ubiquitous bacteria from the aquarium environment. The disease can lead to fish mortality and cause high economic losses if not rapidly controlled. The aim of this study was to identify the main causative bacterial agents of infection in ornamental fish with different clinical signs. A total of 126 freshwater fish, from 12 families and 38 species, with clinical signs were collected in a wholesaler in São Paulo, SP, Brazil. Samples were taken from the eye, skin ulcers, kidneys, and gills, plated on MacConkey, CHROMagar Orientation, and blood agar and incubated under aerobic and anaerobic conditions. Bacterial identification was performed by MALDI-TOF mass spectrometry. From the 126 studied animals, 112 were positive for bacterial isolation. Among the positive animals, 32.1% presented infection caused by a single bacterial species, while in the remaining 67.9%, two to six different bacterial species were identified. A total of 259 bacterial strains were obtained and classified among 46 bacterial species. The species of higher frequency were Aeromonas veronii (26.3%), Aeromonas hydrophilla (16.2%), Shewanella putrefaciens (7.3%), Citrobacter freundii (8.1%), Vibrio albensis (5.8%), and Klebsiella pneumoniae (4.2%). MALDI-TOF MS showed to be a rapid method for diagnosis of bacterial disease outbreaks in ornamental fish establishments.

Avaliação da atividade de água e da contaminação por bolores e leveduras em mel comercializado na cidade de São Paulo – SP, Brasil / Assessment of water activity and molds and yeasts contamination in honey trated on São Paulo city-SP, Brazil

Foram analisadas 60 amostras de mel vendidas em feiras-livres, supermercados e casas de produtos naturais da zona oeste do município de São Paulo, para avaliar a atividade de água – Aa (Aqualab 3TE - Decagon) e a contagem de bolores e leveduras (em ágar batata contendo 2 e 20% de dextrose). A Aa apresentou valor médio de 0,578 e desvio padrão de 0,027, valor mínimo de 0,489 e máximo de 0,661. A contagem de bolores e leveduras apresentou valor mínimo, mediano e máximo, espectivamente de: <0,5x1; <0,5x1 e 3,9x102 UFC/g no ágar 2% de dextrose e <0,5x1; 0,5x10 e 3,9x102 UFC/g no ágar 20%. Não houve diferença significativa entre as contagens obtidas nos meios com 2 e 20% de dextrose, porém houve maior número de amostras com ausência de crescimento no meio 2%. Concluiu-se que 59/60 amostras (98,33%) tinham pouca probabilidade de sofrer fermentação por apresentarem baixas contagens (<15 UFC/g) e/ou Aa (<0,61); apenas 1/60 (1,67%) amostra apresentou uma condição potencial de fermentação, com contagem >100 UFC/g e Aa >0,61; há necessidade de mais informações sobre a importância da osmolaridade do meio de cultura na quantificação e identificação de bolores e leveduras em mel

Linfadenites tuberculóides em suínos abatidos no Estado de Säo Paulo, Brasil: aspectos macroscópicos histopatológicos em pesquisa de micobactérias / Tuberculosis lymphadenitis in slaughtered swine from Säo Paulo State (Brazil): gross lesions, histopathology and demonstration of mycobacteria

Como a ocorrência de linfadenites tuberculóides nos suínos oferece risco à saúde pública, sobretudo em indivíduos imunocomprometidos, foi estudada a distribuiçäo das lesöes tuberculóides e a presença de micobactérias em linfonodos, tecido hepático e muscular de suínos de abate, no Estado de Säo Paulo, SP (Brasil), no período de 1993-1994. Foram estudadas 60 carcaças de suínos abatidos, sendo que, trinta apresentavam lesöes tuberculóides macroscópicas (grupo A) e trinta estavam livres de tais lesöes (grupo B ou controle). Foram analisadas seis localizaçöes: linfonodos (retrofaríngeos, jejunais e mediastínicos), tecido hepático e tecido muscular (masséter e diafragma). Os exames executados foram: histopatologia e o cultivo para micobactérias. No grupo A, 14 em 30 carcaças apresentaram granuloma na histopatologia e, em 14, houve o isolamento de representantes do Complexo MAC (Mycobacterium avium-intracellulare). No grupo B, näo foram observadas lesöes na histopatologia, e de quatro carcaças houve o isolamento de micobactérias de rápido crescimento. As lesöes macroscópicas foram encontradas predominantemente nos linfonodos mesentéricos. O Complexo MAC foi isolado apenas em linfonodos do grupo com lesäo, näo sendo isolado em tecido hepático e muscular. Näo foi possível o estabelecimento de relaçäo entre o tipo de micobactéria isolada e as características macroscópicas das lesöes.