RESUMO
Among the Cronobacter genus, Cronobacter sakazakii is the most common species posing a severe health risk for newborns, infants and children. Some infant formulas, cereal-based foods, and food production environments may be the potential reservoirs of C. sakazakii. This pathogen possesses different virulence factors encoded by different virulence genes. Therefore, characterizing these genes is important for distinguishing pathogenic strains from nonpathogenic ones. The objective of this study was to characterize some virulence genes [OmpA, OmpX, zpx, and Cpa] by real-time polymerase chain reaction (PCR) in C. sakazakii isolates from a total of 120 samples (20 each of milk powder, starch, rice flour, semolina, infant formula and dust samples from food production environments). Overall, 13 isolates (7 from milk powder, 2 rice flour, 1 semolina, and 3 dust) were cultured, identified by bioMérieux API® 20E test kit, and then subjected to real-time PCR application for screening the target virulence-associated genes. Our results showed that all of 13 isolates were positive for the virulence genes OmpA, OmpX, zpx, and Cpa. In summary, our study revealed that some of the analyzed foods and environmental samples were contaminated with pathogenic C. sakazakii with its virulence-associated markers, far above the allowable limit; and therefore, this level of contamination may pose a severe health threat for newborns, infants, and children.(AU)
Dentre o gênero Cronobacter, Cronobacter sakazakii é a espécie mais comum que representa um grave risco para a saúde dos recém-nascidos, bebês e crianças. Algumas formulas infantis para crianças, alimentos a base de cereais e locais de produção de alimentos, foram considerados como potenciais locais de contaminação de C. sakazakii. Este patógeno possui diferentes agentes de virulência codificados por diferentes genes de virulência. Portanto, a caracterização dos genes é importante para distinguir as cepas patogênicas das não patogênicas. O objetivo deste estudo foi caracterizar os diferentes genes de virulência [OmpA, OmpX, zpx, and Cpa] em C. sakazakii isolados em um total de 120 amostras (20 de cada uma delas - leite em pó, amido, farinha de arroz, sêmola, comida para bebês e amostras de poeira provenientes dos ambientes de produção de alimentos) por reação em cadeia da polimerase em tempo real (RT-PCR). No total, foram cultivadas 13 estirpes (7 de leite em pó, 2 de farinha de arroz, 1 de sêmola e 3 poeiras) e depois identificadas pelo kit de teste bio Mérieux API® 20E. As estirpes identificadas foram submetidas ao PCR em tempo real para caracterizar os genes alvo associados à virulência. Os resultados mostraram que todos os genes C. sakazakii isolados eram patogênicos e positivos às OmpA, OmpX, zpx e Cpa com um padrão de coexistência. Em resumo, o nosso estudo revelou que os alimentos e os ambientes de produção de alimentos analisados constituíam uma ameaça à saúde dos recém-nascidos, bebês e crianças devido à contaminação por C. sakazakii patogênico como marcadores associados à virulência.(AU)
Assuntos
Humanos , Recém-Nascido , Lactente , Criança , Cronobacter sakazakii , Infecções por Enterobacteriaceae/transmissão , Fatores de Virulência , Alimentos Infantis/virologia , Grão Comestível/virologia , Turquia , Reação em Cadeia da PolimeraseRESUMO
The wheat curl mite (WCM), Aceria tosichella, and the plant viruses it transmits represent an invasive mite-virus complex that has affected cereal crops worldwide. The main damage caused by WCM comes from its ability to transmit and spread multiple damaging viruses to cereal crops, with Wheat streak mosaic virus (WSMV) and Wheat mosaic virus (WMoV) being the most important. Although WCM and transmitted viruses have been of concern to cereal growers and researchers for at least six decades, they continue to represent a challenge. In older affected areas, for example in North America, this mite-virus complex still has significant economic impact. In Australia and South America, where this problem has only emerged in the last decade, it represents a new threat to winter cereal production. The difficulties encountered in making progress towards managing WCM and its transmitted viruses stem from the complexity of the pathosystem. The most effective methods for minimizing losses from WCM transmitted viruses in cereal crops have previously focused on cultural and plant resistance methods. This paper brings together information on biological and ecological aspects of WCM, including its taxonomic status, occurrence, host plant range, damage symptoms and economic impact. Information about the main viruses transmitted by WCM is also included and the epidemiological relationships involved in this vectored complex of viruses are also addressed. Management strategies that have been directed at this mite-virus complex are presented, including plant resistance, its history, difficulties and advances. Current research perspectives to address this invasive mite-virus complex and minimize cereal crop losses worldwide are also discussed.