Denisa S Perez is a Veterinarian and she has completed her PhD from the National University of Buenos Aires Province (Argentina). She is performing Postdoctoral Studies at the Toxicology Area in the Physiopathology Department of Tandil Veterinary Research Center. She is also a Professor at Veterinary Sciences Faculty. She has published an important amount of research articles in reputed journals.rn
Deoxynivalenol (DON) is a mycotoxin which inhibits protein synthesis and causes cytotoxicity. Fosfomycin (FOS) is a bactericidal broad-spectrum antibiotic used in human and veterinary medicine with some extra antimicrobial properties. We have demonstrated that after 4 hours of incubation, FOS was able to prevent the cytopathic effect of DON on Hep2 cells. To corroborate these results and to determine whether the effect of DON was due to the induction of apoptosis, Hep2 cells were seeded in 6 well-plates and after 24 hours, cell monolayers were treated with DON (2.8 μg/mL) alone or with DON (2.8 μg/mL) and FOS (550 μg/mL). The presence of nuclear morphological changes representative of apoptosis was evaluated by DAPI staining under immunofluorescence microscope, the percentage of apoptotic cells was determined and the results were evaluated by ANOVA/Tukey test. Cell cultures incubated with DON and FOS were similar to control wells showing the absence of cytotoxicity. Apoptotic cells percentage was significantly higher (5.64+0.27) (p<0.01) for cells treated with DON than for cells incubated with both the mycotoxin and the antibiotic (0.65+0.5). To determine whether DON was able to induce apoptosis in different cells lines and at lower concentrations, MDBK and BHK cells were also treated with DON at 1 μg/mL for 24 hours. Results show that the mycotoxin induces apoptosis in all the assayed cell lines. Further studies are needed to confirm that the protective effect of the antibiotic occurs in all cell lines and its implications under in vivo conditions.
Grammato Evangelopoulou is a Military Veterinarian specialized in Food Microbiology. Currently she is carrying out her Doctoral studies in the Faculty of Veterinary Medicine, University of Thessaly, Greece. Her Research interests focus on pig salmonellosis and its impact to Public Health. She is a Member of the American Society for Microbiology. Her work is supervised by Professor A R Burriel, Director of The Microbiology and Parasitology Laboratory, University of Thessaly.
The ability of a microorganism to produce H2S is an important taxonomic characteristic within the family of Enterobacteriaceae with Citrobacter spp., Proteus spp. and Salmonella spp. considered major H2S-producers. H2S is a very toxic compound for mammalian cells helping perhaps, bacteria producing it to colonize or damage tissues thus playing a role in the development of gastroenteritis and ulcerative colitis. The toxicity of H2S to mammalian cells is comparable to that of cyanide when their LD50 is determined using rodents. About 97.7% of Salmonella spp. serovars other than S. choleraesuis and S. typhi produce H2S. Loss of H2S production is observed in environmental strains of Salmonella spp. resulting from mutations or its \"masking\" by acid production during sugar fermentation on frequently used culture media. In this study, five (5) lactose positive Salmonella spp. and three (3) E. coli isolates recovered using ISO 6579:2002 (Annex D), appeared H2S negative when cultured on XLD and SS agars but they produced it when co-cultured with typically strong H2S-producing Salmonella isolates. This observation emphasizes possible failures in the identification of Salmonella pathogenic serovars and the possibility of a synergistic increase in the pathogenicity of less pathogenic serovars or other enterobacteria.