Salmonella spp is a pathogen responsible for severe foodborne infections, can be introduced into the fish production chain through inadequate handling or hygiene or contact with contaminated water, and is not a biological contaminant originally reported in fish. Fish microbiological safety is a concern for consumers, industries and regulatory agencies worldwide, since fish, an important food category in the international trade and often exported to several countries, can act as a vehicle for Salmonella transmission throughout the production chain. In addition, concerns regarding the misuse of antibiotics in aquaculture are also an issue, as a result of the increased isolation of resistant and multiresistant Salmonella serovars. In this review, we examined aspects associated with the microbiological risks of the presence of Salmonella spp. in fish and their implication in the aquaculture production chain. In addition, incidence and antimicrobial resistance data are presented, as well as strategies for Salmonella prevention and control in fish.

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Salmonella spp. in the fish production chain: a review

Foodborne, disease-causing microorganisms are increasingly resistant to commercial antibiotics. Thus, there is a need for the development of new agents capable of acting efficiently in the control of these pathogens. Terpenoids and phenylpropanoids stand out for having high biological activity and a broad spectrum of action. The objectives of this study were to evaluate the antibacterial potential of limonene, β-citronellol, carvone, carvacrol, eugenol and trans-cinnamaldehyde and to investigate the mechanism of activity of these compounds against the bacteria Escherichia coli and Staphylococcus aureus. The terpene and phenylpropanoid compoundswere purchased and their antibacterial potential was assessed by macrodilution. The mechanism of action was verified by tests of potassium ion efflux, salt tolerance, extravasation of cellular contents, absorption of crystal violet and morphological changes analyzed by electron microscopy. Bacteriostatic and bactericidal effects caused by the compounds carvone, carvacrol, eugenol and transcinemaldehyde were observed in both species; antibacterial activity against only S. aureus was observed for β-citronelol and limonene. Reduced salt tolerance was found for strains of E. coli treated with carvacrol and S. aureus treated with β-citronelol. There was extravasation of cellular materials induced by treatments with carvone, carvacrol, eugenol and trans-cinnamaldehyde in both microorganisms. The absorption of crystal violet increased for E. coli after incubation with each treatment. Deleterious effects and morphological changes were observed. Therefore, the monoterpenes and phenylpropanoids under study are potentially applicable for antimicrobial use against E. coli and S. aureus, and the mechanism of action involves changes in membrane permeability without cell lysis.

Mechanism of action of various terpenes and phenylpropanoids against Escherichia coli and Staphylococcus aureus

Role of the thymus and the bursa of Fabricus in immune reactions in chickens. I. Change in lymphoid tissues of chickens surgically thymectomized at hatching

Development and application of a new multiplex real‐time PCR assay for simultaneous identification of Brucella melitensis, Cronobacter sakazakii and Listeria monocytogenes in raw milk and cheese

SUMMARY The present study aimed to identify and quantify the components of the essential oil of Zanthoxylum caribaeum and to evaluate the antimicrobial potential of different plant extracts and the essential oil of this plant against different serotypes of Salmonella enterica, which is of greater occurrence and isolated in the western region of Parana, Brazil. The extraction of the essential oil was performed using Clevenger apparatus and the chemical composition was determined by Gas Chromatography coupled to Mass Spectrometry (GC-MS). The extracts were obtained through different solvents (ethanol, methanol, hexane, acetone, dichloromethane, ethyl acetate and distilled water). The antibacterial activity was carried out according to the broth microdilution technique. The GC-MS analysis resulted in the identification of 15 main components, all terpenes, representing 63.88% of the total essential oil. The major compounds identified were Germacrene-D (20.77%), a-Panasinsene (14.40 %) and b-Selinene (11.68 %). The essential oil presented antibacterial activity against 5 serotypes of Salmonella enterica, with MIC and MBC ranging from 7000 to 437 μg.mL-1. While MIC and MBC from the range from 200 to 25 mg.mL-1, being effective to most serotypes of S. enterica, with the exception of the aqueous extract. The results suggest that the essential oil and leaf extracts of Z. caribaeum represent an alternative for the control of S. enterica in the poultry sector, in this way reflecting a new perspective for studies with natural products.

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Chemical composition and antibacterial activity of essential oil and leaf extracts of Zanthoxylum caribaeum Lam. against serotypes of Salmonella

Real-time PCR detection of Brucella spp. DNA in lesions and viscera of bovine carcasses.

Thirty fowls (Gallus gallus) of the Bovans Goldline lineage were studied, with fifteen weeks of age, with the objective to determine the number of lobes, the origin and number of the arteries of the thymus. The fowls were dissected after injection of 50% aqueous ruddy solution of “Neoprene Latex 450”, through the left isquiatic artery and further fixed in a 10% formaldehyde aqueous solution, for at least 48 hours. The thymus was irrigated by direct branches from common vagus nerve arteries, ascending cutaneous cervical arteries, cranial thyroidea arteries and cutaneous branches from both side and from right ingluvial artery. The number of lobes of the thymus ranged from the two to six from both side. The number of arteries, regardless of their origin and of their side, varied from seven to twenty and five.

ARTÉRIAS DO TIMO EM AVES (Gallus gallus) POEDEIRAS DA LINHAGEM BOVANS GOLDLINE ARTERIES OF THYMUS IN BIRDS (Gallus gallus) OF THE BOVANS GOLDLINE LINEAGE

Quorum sensing caracteriza-se por um sistema de comunicacao intra e interespecies de microrganismos, baseado na emissao de estimulos e respostas dependentes da densidade populacional. Este tipo de interacao reflete o comportamento dos microrganismos, demonstrando a capacidade de habitar ambientes diversos, captar as informacoes de seu meio, comunicar-se com diferentes especies, monitorar sua densidade populacional e principalmente regular a sua expressao genica, controlando processos celulares como a esporulacao, formacao de biofilmes, expressao de fatores de virulencia, producao de bacteriocinas e antibioticos e a bioluminescencia. Acredita-se tambem que este sistema de comunicacao celular desempenhe funcoes importantes na ecologia microbiana de alimentos, tanto na deterioracao destes produtos quanto na multiplicacao de patogenos e producao de toxinas.

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Mecanismos de quorum sensing e sua relevância na microbiologia de alimentos

Diante da necessidade de desenvolvimento biotecnologico e cientifico, a preservacao e a manutencao de materiais biologicos vem ganhando destaque no cenario mundial. A garantia de sobrevivencia de culturas bem como a conservacao de suas caracteristicas morfologicas, fisiologicas e geneticas sao primordiais na adequacao de metodos de preservacao de celulas humanas, animais e vegetais, bacterias, virus, fungos e material genetico (DNA/RNA), porem nao existe uma formula ideal ou universal para essa conservacao. Desta forma a escolha de um metodo de manutencao deve ser baseada nas caracteristicas do material biologico em estudo, assim como nas vantagens e desvantagens de cada tecnica disponivel. Neste contexto, a preservacao ex situ em colecoes de culturas vem garantindo a sobrevivencia, a estabilidade e pureza de linhagens durante longos periodos, empregando diversos metodos de manutencao e principalmente disponibilizando as culturas para a comunidade cientifica e tecnologica de diversos paises.

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Manutenção de microrganismos: conservação e viabilidade

A qualidade microbiologica do leite cru pode ser influenciada diretamente pela sanidade dos animais, procedimentos de higiene realizados durante a ordenha e condicoes de armazenamento do produto. Diante da necessidade de caracterizar os aspectos microbiologicos relacionados a producao de leite do rebanho bovino da raca Curraleiro Pe-Duro, foram avaliadas 226 amostras de leite cru colhidas no periodo de janeiro de 2013 a janeiro de 2014, visando a pesquisa de Salmonella sp. Os ensaios analiticos foram realizados no Laboratorio Multiusuario de Microbiologia do Centro de Pesquisa em Alimentos da Escola de Veterinaria da Universidade Federal de Goias.  A partir dos resultados obtidos foi observado a presenca de Salmonella sp. em seis amostras de leite da raca Curraleiro Pe-Duro, com destaque aos sorovares Heidelberg e Schwarzengrund. Apesar deste microrganismo compor a microbiota intestinal normal de seres humanos e animais de sangue quente, ser eliminada pelas fezes e consequentemente promover a contaminacao do ambiente e outros animais, a identificacao de Salmonella em leite cru ressalta a necessidade de controle no processo de obtencao do leite, armazenamento e processamento da materia-prima e derivados a fim de assegurar seguranca aos consumidores.

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Marília Cristina Sola

Papers

Real-time PCR detection of Brucella spp. DNA in lesions and viscera of bovine carcasses.

ARTÉRIAS DO TIMO EM AVES (Gallus gallus) POEDEIRAS DA LINHAGEM BOVANS GOLDLINE ARTERIES OF THYMUS IN BIRDS (Gallus gallus) OF THE BOVANS GOLDLINE LINEAGE

Mecanismos de quorum sensing e sua relevância na microbiologia de alimentos

Manutenção de microrganismos: conservação e viabilidade

Identificação de Salmonella sp. em leite da raça Curraleiro Pé-Duro