Molecular Characterization and the Antimicrobial Resistance Profile of Salmonella spp. Isolated from Ready-to-Eat Foods in Ouagadougou, Burkina Faso.

The emergence of antimicrobial-resistantfood-borne bacteria is a great challenge to public health. This study was conducted to characterize and determine the resistance profile of Salmonella strains isolated from foods including sesames, ready-to-eat (RTE) salads, mango juices, and lettuce in Burkina Faso. One hundred and forty-eight biochemically identified Salmonella isolates were characterized by molecular amplification of Salmonella marker invA and spiC, misL, orfL, and pipD virulence genes. After that, all confirmed strains were examined for susceptibility to sixteen antimicrobials, and PCR amplifications were used to identify the following resistance genes: bla TEM, temA, temB, StrA, aadA, sul1, sul2, tet(A), and tet(B). One hundred and eight isolates were genetically confirmed as Salmonella spp. Virulence genes were observed in 57.4%, 55.6%, 49.1%, and 38% isolates for pipD, SpiC, misL, and orfL, respectively. Isolates have shown moderate resistance to gentamycin (26.8%), ampicillin (22.2%), cefoxitin (19.4%), and nalidixic acid (18.5%). All isolates were sensitive to six antibiotics, including cefotaxime, ceftazidime, aztreonam, imipenem, meropenem, and ciprofloxacin. Among the 66 isolates resistant to at least one antibiotic, 11 (16.7%) were multidrug resistant. The Multiple Antimicrobial Resistance (MAR) index of Salmonella serovars ranged from 0.06 to 0.53. PCR detected 7 resistance genes (tet(A), tet(B), bla TEM, temB, sul1, sul2, and aadA) in drug-resistant isolates. These findings raise serious concerns because ready-to-eat food in Burkina Faso could serve as a reservoir for spreading antimicrobial resistance genes worldwide.

Assessment of the sanitary quality of ready to eat sesame, a low moisture street food from Burkina Faso.

BACKGROUND: Microbial contamination of edible low moisture food poses a significant public health risk for human. In this study, the microbial quality of sweet dehulled sesame seed croquettes, salted dehulled sesame seed and the raw sesame seed, sold under ambient conditions were examined. The samples were collected in the cities of Burkina Faso. The first type is sweet dehulled sesame seed croquettes (n1 = 25); the second type is salted dehulled sesame seed (n2 = 25) and the third type is raw sesame seed (n3 = 25). Assessment of the microbial quality was based on the total aerobic mesophilic bacteria, the thermotolerant coliforms, the yeasts and moulds, the E. coli, and the Salmonella spp. using ISO methods. RESULTS: The results showed the presence of microorganisms varying from <1.0 to 1.72 × 105 CFU g- 1 for thermotolerant coliforms, from <1.0 to 6,12 × 106 CFU g- 1 for the total mesophilic aerobic flora and from <1.0 to 8.10 × 105 CFU g- 1 for yeasts and moulds. The higher contaminations rates were mostly observed in raw sesame seed samples. No E coli or Salmonella pathogens were detected. Based on international standards of dehydrated food, 50.67% of the ready to eat sesame are satisficing while 17.33% are acceptable and 32% are not satisficing. CONCLUSION: Attention should be emphasized on the processing practices, especially in crowded places where RTE sesames seeds are mostly sold. The high numbers of all microbial groups in these sesame seed samples suggested that the production of RTE sesame seed should be improved by better hygiene. This study highlights also that RTE sesame seed might harbor a wide range of microorganisms when processes are weak of hygiene.

Identification of ribosomal phosphoprotein P0 of Neospora caninum as a potential common vaccine candidate for the control of both neosporosis and toxoplasmosis.

The characterization of the cross-reactive antigens of two closely related apicomplexan parasites, Neospora caninum and Toxoplasma gondii, is important to elucidate the common mechanisms of parasite-host interactions. In this context, a gene encoding N. caninum ribosomal phosphoprotein P0 (NcP0) was identified by immunoscreening of a N. caninum tachyzoite cDNA expression library with antisera from mice immunized with T. gondii tachyzoites. The NcP0 was encoded by a gene with open reading frame of 936 bp, which encoded a protein of 311 amino acids. The NcP0 gene existed as a single copy in the genome and was interrupted by a 432 bp intron. The NcP0 showed 94.5% amino acid identity to T. gondii P0 (TgP0). Anti-recombinant NcP0 (rNcP0) sera recognized a native parasite protein with a molecular mass of 34 kDa in Western blot analysis. Immunofluorescence analysis showed that the NcP0 was localized to the surface of N. caninum tachyzoites. A purified anti-rNcP0 IgG antibody inhibited the growth of N. caninum and T. gondii in vitro in a concentration-dependent manner. These results indicate that P0 is a cross-reactive antigen between N. caninum and T. gondii and a potential common vaccine candidate to control both parasites.

Apical membrane antigen 1 is a cross-reactive antigen between Neospora caninum and Toxoplasma gondii, and the anti-NcAMA1 antibody inhibits host cell invasion by both parasites.

The cross-reactive antigens of Neospora caninum and Toxoplasma gondii are important in the exploration to determine the common mechanisms of parasite-host interaction. In this study, a gene encoding N. caninum apical membrane antigen 1 (NcAMA1) was identified by immunoscreening of a N. caninum tachyzoite cDNA expression library with antisera from mice immunized with recombinant T. gondii apical membrane antigen 1 (TgAMA1). NcAMA1 was encoded by an open reading frame of 1695 bp, which encoded a protein of 564 amino acids. The single-copy NcAMA1 gene was interrupted by seven introns. NcAMA1 showed 73.6% amino acid identity to TgAMA1. Mouse polyclonal antibodies raised against the recombinant NcAMA1 (rNcAMA1) recognized a 69-kDa native parasite protein by Western blotting. Immunofluorescence analysis showed that NcAMA1 was localized to the apical end of tachyzoites. Two-dimensional electrophoresis and Western blotting indicated that an approximately 57-kDa cleavage product was released into the excretory/secretory products of N. caninum. Preincubation of free tachyzoites with anti-rNcAMA1 IgG antibodies inhibited the invasion into host cells by N. caninum and T. gondii. These results indicated that AMA1 is a cross-reactive antigen between N. caninum and T. gondii and a potential common vaccine candidate to control two parasites.