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A study was conducted to examine the levels of Salmonella spp. contamination in raw food samples, including chicken, beef, pork, and shellfish, from Vietnam and to determine their antibiotic resistance characteristics. A total of 180 samples were collected and examined for the presence of Salmonella spp., yielding 91 Salmonella isolates. Sixty-one percent of meat and 18% of shellfish samples were contaminated with Salmonella spp. Susceptibility of all isolates to a variety of antimicrobial agents was tested, and resistance to tetracycline, ampicillin/amoxicillin, nalidixic acid, sulfafurazole, and streptomycin was found in 40.7%, 22.0%, 18.7%, 16.5%, and 14.3% of the isolates, respectively. Resistance to enrofloxacin, trimethoprim, chloramphenicol, kanamycin, and gentamicin was also detected (8.8 to 2.2%). About half (50.5%) of the isolates were resistant to at least one antibiotic, and multiresistant Salmonella isolates, resistant to at least three different classes of antibiotics, were isolated from all food types. One isolate from chicken (serovar Albany) contained a variant of the Salmonella genomic island 1 antibiotic resistance gene cluster. The results show that antibiotic resistance in Salmonella spp. in raw food samples from Vietnam is significant.

Over the last century, the successful attenuation of multiple bacterial and viral pathogens has led to an effective, robust and safe form of vaccination. Recently, these vaccines have been evaluated as delivery vectors for heterologous antigens, as a means of simultaneous vaccination against two pathogens. The general consensus from published studies is that these vaccine vectors have the potential to be both safe and efficacious. However, some of the commonly employed vectors, for example Salmonella and adenovirus, often have pre-existing immune responses in the host and this has the potential to modify the subsequent immune response to a vectored antigen. This review examines the literature on this topic, and concludes that for bacterial vectors there can in fact, in some cases, be an enhancement in immunogenicity, typically humoral, while for viral vectors pre-existing immunity is a hindrance for subsequent induction of cell-mediated responses.

Ten strains of an unknown Campylobacter species were isolated from the livers of chickens with spotty liver disease in Australia. The strains were Gram-stain-negative, microaerobic, catalase- and oxidase-positive and urease-negative. Unlike most other species of the genus Campylobacter, most of the tested strains of this novel species hydrolysed hippurate and half of them could not reduce nitrate. All strains showed resistance, or intermediate resistance, to nalidixic acid and most of them were resistant to cephalothin. Examination of negatively stained cells under transmission electron microscopy revealed that they were S-shaped, with bipolar unsheathed flagella. Phylogenetic analyses based on the 16S rRNA gene and the heat shock protein 60 (hsp60) gene sequences indicated that the strains formed a robust clade that was clearly distinct from recognized Campylobacter species. Unusually, they had a DNA G+C content of 27.9 mol%, lower than any previously described Campylobacter species, and they showed less than 84 % average nucleotide identity to the nearest sequenced species. Taken together, these data indicate that the strains belong to a novel Campylobacter species, for which the name Campylobacter hepaticus sp. nov. is proposed. The type strain is HV10T (=NCTC 13823T=CIP 111092T).