The genus Aeromonas contains important pathogen for both humans and other animals, being responsible for the etiology of intestinal and extraintestinal diseases. The pathology caused by these bacteria involves several virulence factors, such as the ability to produce toxins, adhesion and invasion. The properties conferred by these factors have been extensively studied in experiments of interaction between bacterial strains and cell culture. We evaluate the interaction of eight Aeromonas spp. strains, previously isolated from human faeces, food and water with HEp-2, Caco-2 and T-84 cell lines. Cytotoxic effects, the pattern of adhesion, invasive capacity and intracellular survival were analyzed. The results showed that Aeromonas strains were adherent to three cells lines in 6 h of incubation, displaying the aggregative adherence pattern. Among eight strains studied, 50% produced cytotoxic effects on HEp-2 cells, while none of the strains produced cytotoxic effects on Caco-2 and T-84 cells at 48 h. This study demonstrated that subsets of Aeromonas isolated from different sources were able to invade intestinal (T-84, Caco-2) and epithelial (HEp-2) cell lines cultivated in vitro surviving in intracellular environments up to 72 h. Finally, our results support the pathogenic potential of Aeromonas, especially those of food and clinical sources.
Brazilian flora includes numerous species of medicinal importance that can be used to
develop new drugs. Plant tissue culture offers strategies for conservation and use of
these species allowing continuous production of plants and bioactive substances.
Annona mucosa has produced substances such as acetogenins and
alkaloids that exhibit antimicrobial activities. The widespread use of antibiotics
has led to an increase in multidrug-resistant bacteria, which represents a serious
risk of infection. In view of this problem, the aim of this work was to evaluate the
antibacterial potential of extracts of A. mucosa obtained by
in vitro techniques and also cultured under in
vivo conditions. Segments from seedlings were inoculated onto different
culture media containing the auxin picloram and the cytokinin kinetin at different
concentrations. The calluses obtained were used to produce cell suspension cultures.
The materials were subjected to methanol extraction and subsequent fractionation in
hexane and dichloromethane. The antimicrobial activity against 20 strains of clinical
relevance was evaluated by the macrodilution method at minimum inhibitory and minimum
bactericidal concentrations. The extracts showed selective antimicrobial activity,
inhibiting the growth of Streptococcus pyogenes and Bacillus
thuringiensis at different concentrations. The plant tissue culture
methods produced plant materials with antibacterial properties, as well as in
vivo grown plants. The antibacterial activity of material obtained
through biotechnological procedures of A. mucosa is reported here
for the first time.
BACKGROUND: Enteroaggregative Escherichia coli (EAEC) is an E. coli pathotype that presents aggregative adhesion patterns on in vitro cultivated cells, mainly related to persistent diarrhea cases in children. EAEC virulence factors are important for host colonization and pathogenicity. Intestinal epithelial cells (IECs) recognize pathogen-associated molecular patterns (PAMPs) and initiate an immune response. Several studies using in vivo and in vitro models emphasize the probiotic activity and immunomodulatory capacity of Lactobacillus and Bifidobacterium species. OBJECTIVE To evaluate the modulation of cytokine production by probiotics Bifidobacterium animalis and Lactobacillus casei in human intestinal Caco-2 cells exposed to different strains of EAEC. METHODS: Caco-2 cells were incubated with EAEC strains in the presence or absence of probiotics. The production of cytokines IL-8, TNF-α, IL-1β and IL-10 was evaluated in the supernatants by a sandwich enzyme-linked immunosorbent assay (ELISA). RESULTS: Cytokine production did not change when uninfected and EAEC-infected Caco-2 cells were exposed to probiotics separately. All EAEC induced a significant increase in IL-8 production by Caco-2 cells, but the probiotics, even together, could not reduce its production. On the other hand, the synergic activity of probiotic strains significantly increased TNF-α production but decreased the basal production of IL-1ß. Also, probiotics induced a significant increase in the production of the anti-inflammatory cytokine IL-10 during EAEC infection. CONCLUSION: Our results reinforce the synergistic immunomodulatory activity of probiotics during EAEC infection.
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