Cytokine expression and Mycoplasma hyopneumoniae burden in the development of lung lesions in experimentally inoculated pigs.

This study aimed to assess immunopathological factors and M. hyopneumoniae (M. hyo) load in macroscopic lesion formation at four timepoints after experimental infection of swine. To do this, 24 M. hyo-free pigs were divided into two groups: non-inoculated control (n = 8) and inoculated (n = 16). At day 0 post-infection (dpi), animals of infected group were intratracheally inoculated with 5 mL of lung inoculum containing 107 CCU (Color Changing Units) ∕mL of M. hyo strain 232, while control group was mock infected with 5 mL of sterilized Friis medium. At 14, 28, 42 and 56 dpi, four animals from the infected group and two from the control group were euthanized and necropsied. The extent of macroscopic lung lobe lesions was visually assessed, scored and lesion samples (qPCR, histopathology and gene expression) were collected. The macroscopic lesion score and estimated M. hyo load (in copies/µL) at the different timepoints were: 14 dpi: 18.5 %-1.55 × 103 copies∕µL; 28dpi: 15.8 %-8.4 × 103 copies∕µL; 42 dpi: 7.0 %-3.2 × 104 copies∕µL and 56 dpi: 6.3 %-1.11 × 105 copies∕µL; Significant and positive correlations between macroscopic lung lesion and the pathogen load were found (coefficient range: 0.77-0.99). The cytokine's IL-6 (0.73) and INF-γ (-0.69) gene expression were significantly (p < 0.05) correlated to macroscopic lung lesion score while IL-8, TNF- α, IL-1α and IL-1ß were associated to other pathological effects such as losses in average daily weight gain and microscopic lesion score. The results provide a better understanding about the pathogenicity of M. hyo strain 232 and the host-pathogen interactions, which may be helpful for the development of new treatments or control measures.

High occurrence of ß-lactamase-producing Salmonella Heidelberg from poultry origin.

Salmonella Heidelberg is commonly reported in foodborne outbreaks around the world, and chickens and poultry products are known as important source of these pathogen. Multidrug-resistant S. Heidelberg strains are disseminated into poultry production chair, which can lead to severe clinical infections in humans and of difficult to treat. This study aimed at evaluating the ß-lactam susceptibility and genotypic relatedness of Salmonella Heidelberg at Brazilian poultry production chain. Sixty-two S. Heidelberg strains from poultry production chain (poultry, poultry meat and poultry farm) were used. All strains were evaluated to antimicrobial susceptibility by diffusion disk test, as well as ß-lactam resistance genes. Genotypic relatedness was assessed by Pulsed-Field Gel Eletrophoresis, using Xba1 restriction enzyme. Forty-one strains were characterized as multidrug-resistant according to phenotype characterization. The resistance susceptibility revealed 31 distinct profiles, with higher prevalence of streptomycin (61/62), nalidixic acid (50/62), tetracycline (43/62) and ß-lactam drugs (37/62). blaCMY-2 was the more frequent ß-lactamase gene found (38/62); other resistance genes found were blaCTX-M (2/62), blaSHV (3/62) and blaTEM-1 (38/62). No carbapenemase genes was found. The Pulsed-Field Gel Electrophoresis showed 58 different profiles. Strains with a larger number of antimicrobial resistance were grouped into ten major clusters apart from others. The spread of resistance by ampC continues to rise, thereby turning concern to public health, since the ß-lactam antimicrobials are used as a therapeutic treatment in humans.