ABSTRACT
Salmonella enterica Enteritidis forms biofilms and survives in agricultural environments, infecting poultry and eggs. Bacteria in biofilms are difficult to eradicate compared to planktonic cells, causing serious problems in industry and public health. In this study, we evaluated the role of ihfA and ihfB in biofilm formation by S. enterica Enteritidis by employing different microbiology techniques. Our data indicate that ihf mutant strains are impaired in biofilm formation, showing a reduction in matrix formation and a decrease in viability and metabolic activity. Phenotypic analysis also showed that deletion of ihf causes a deficiency in curli fimbriae expression, cellulose production and pellicle formation. These results show that integration host factor has an important regulatory role in biofilm formation by S. enterica Enteritidis.
Subject(s)
Biofilms/growth & development , Fimbriae, Bacterial/genetics , Gene Expression Regulation, Bacterial , Integration Host Factors/genetics , Plankton/genetics , Salmonella enteritidis/genetics , Cellulose/biosynthesis , Fimbriae, Bacterial/metabolism , Gene Deletion , Genetic Fitness , Integration Host Factors/deficiency , Plankton/growth & development , Plankton/metabolism , Polysaccharides, Bacterial/biosynthesis , Polysaccharides, Bacterial/deficiency , Protein Subunits/deficiency , Protein Subunits/genetics , Salmonella enteritidis/growth & development , Salmonella enteritidis/metabolism , Salmonella enteritidis/pathogenicityABSTRACT
Salmonella enterica Enteritidis forms biofilms and survives in agricultural environments, infecting poultry and eggs. Bacteria in biofilms are difficult to eradicate compared to planktonic cells, causing serious problems in industry and public health. In this study, we evaluated the role of ihfA and ihfB in biofilm formation by S. enterica Enteritidis by employing different microbiology techniques. Our data indicate that ihf mutant strains are impaired in biofilm formation, showing a reduction in matrix formation and a decrease in viability and metabolic activity. Phenotypic analysis also showed that deletion of ihf causes a deficiency in curli fimbriae expression, cellulose production and pellicle formation. These results show that integration host factor has an important regulatory role in biofilm formation by S. enterica Enteritidis.
ABSTRACT
Abstract Escherichia coli is the major causative agent of human cystitis. In this study, a preliminary molecular analysis carried out by PCR (polymerase chain reaction) demonstrated that 100% of 31 E. coli strains isolated from patients with recurrent UTIs (urinary tract infections) showed the presence of the curli fimbria gene (csgA). Curli fimbria is known to be associated with bacterial biofilm formation but not with the adhesion of human cystitis-associated E. coli. Therefore, this work aimed to study how curli fimbria is associated with uropathogenic E. coli (UPEC) as an adhesion factor. For this purpose, the csgA gene was deleted from strain UPEC-4, which carries three adhesion factor genes (csgA, fimH and ompA). The wild-type UPEC-4 strain and its mutant (ΔcsgA) were analyzed for their adhesion ability over HTB-9 (human bladder carcinoma), Vero (kidney cells of African green monkey) and HUVEC (human umbilical vein) cells in the presence of α-D-mannose. All the wild-type UPEC strains tested (100%) were able to adhere to all three cell types, while the UPEC-4 ΔcsgA mutant lost its adherence to HTB-9 but continued to adhere to the HUVEC and Vero cells. The results suggest that curli fimbria has an important role in the adhesion processes associated with human UPEC-induced cystitis.
Subject(s)
Humans , Adhesins, Escherichia coli/metabolism , Cystitis/microbiology , Escherichia coli Proteins/metabolism , Escherichia coli Infections/microbiology , Uropathogenic Escherichia coli/metabolism , Bacterial Adhesion , Gene Expression Regulation, Bacterial , Sequence Deletion , Adhesins, Escherichia coli/genetics , Escherichia coli Proteins/genetics , Uropathogenic Escherichia coli/geneticsABSTRACT
Escherichia coli is the major causative agent of human cystitis. In this study, a preliminary molecular analysis carried out by PCR (polymerase chain reaction) demonstrated that 100% of 31 E. coli strains isolated from patients with recurrent UTIs (urinary tract infections) showed the presence of the curli fimbria gene (csgA). Curli fimbria is known to be associated with bacterial biofilm formation but not with the adhesion of human cystitis-associated E. coli. Therefore, this work aimed to study how curli fimbria is associated with uropathogenic E. coli (UPEC) as an adhesion factor. For this purpose, the csgA gene was deleted from strain UPEC-4, which carries three adhesion factor genes (csgA, fimH and ompA). The wild-type UPEC-4 strain and its mutant (ΔcsgA) were analyzed for their adhesion ability over HTB-9 (human bladder carcinoma), Vero (kidney cells of African green monkey) and HUVEC (human umbilical vein) cells in the presence of α-d-mannose. All the wild-type UPEC strains tested (100%) were able to adhere to all three cell types, while the UPEC-4 ΔcsgA mutant lost its adherence to HTB-9 but continued to adhere to the HUVEC and Vero cells. The results suggest that curli fimbria has an important role in the adhesion processes associated with human UPEC-induced cystitis.
Subject(s)
Adhesins, Escherichia coli/metabolism , Cystitis/microbiology , Escherichia coli Infections/microbiology , Escherichia coli Proteins/metabolism , Uropathogenic Escherichia coli/metabolism , Adhesins, Escherichia coli/genetics , Bacterial Adhesion , Escherichia coli Proteins/genetics , Gene Expression Regulation, Bacterial , Humans , Sequence Deletion , Uropathogenic Escherichia coli/geneticsABSTRACT
Os alimentos são passíveis de contaminação por diferentes agentes etiológicos que podem levar ao desenvolvimento de doenças desencadeadas por micro-organismos patogênicos ou suas toxinas. O alimento preparado e armazenado de forma inadequada pode ser veículo de doenças. Este estudo avaliou as condições higiênico-sanitárias de preparo da merenda escolar. Para esta avaliação, foi realizada a análise microbiológica das amostras coletadas das mãos dos manipuladores, da água utilizada no preparo e higienização dos alimentos; e um check-list foi utilizado para analisar as condições físicas, estruturais e de limpeza das cozinhas. Foram analisadas 31 amostras obtidas de swab de mão, 21 amostras de água e as condições das cozinhas foram avaliadas por meio de um questionário. Este estudo aponta a necessidade de realizar treinamento dos manipuladores de alimento e de efetuar implementação de controle mais rigoroso da água utilizada no preparo dos alimentos. A presente investigação mostrou também que as escolas avaliadas mantêm bom padrão quanto à conservação e limpeza das cozinhas.
Subject(s)
School Feeding , Child Day Care Centers , Food Handling , Food MicrobiologyABSTRACT
O consumo de vegetais minimamente processados vem crescendo devido às exigências dos consumidores por produtos de fácil preparo. Este produto, por ser extremamente manipulado, pode ser contaminado por microorganismos deteriorantes, como as leveduras, que possuem a capacidade de diminuir a vida útil do alimento. Neste sentido, visando à preocupação com a resistência de micro-organismos aos métodos de sanitização utilizados pelas indústrias de alimentos e diante da necessidade de maiores estudos do poder antimicrobiano do ozônio, este estudo teve por objetivo isolar e identificar as leveduras presentes nos vegetais minimamente processados e verificar sua resistência antimicrobiana frente ao hipoclorito de sódio e ozônio. Foram coletadas 84 amostras de vegetais minimamente processados. Destas, foram isoladas 47 culturas de leveduras que foram submetidas à identificação e ao ensaio de resistência ao hipoclorito de sódio (50, 100, 200 e 400 ppm) e ozônio (0,25 e 0,5 ppm). Do total de leveduras isoladas, 85,1 corresponderam à Cryptococcus laurentii, 12,8 à Arxula adeninivorans e 2,1 à Debaryomyces hansenii var. fabryii. Todas elas apresentaram resistência aos sanitizantes hipoclorito de sódio e ozônio em todas as concentrações testadas. Diante destas observações, medidas devem ser adotadas durante o processamento para evitar a contaminação por microbiota deteriorante.
