Salmonella Heidelberg is one of the 3 most frequently isolated serovars from human Salmonella cases in Canada, and the fourth most commonly reported Salmonella serovar in human foodborne disease cases in the United States. Since 1962, Salmonella Heidelberg has been isolated and reported in poultry and poultry products in Brazil. The poultry industry has focused efforts on reducing salmonellae incidence in live production in an effort to reduce Salmonella in the processing plant. A better understanding of the initial infection in chicks could provide approaches to control Salmonella contamination. The objective of the present study was to evaluate 2 Salmonella Heidelberg strains that differed in the presence of virulence genes invA, agfA, and lpfA; antimicrobial resistance profiles; and epidemiologic profiles on aspects of pathogenicity and intestinal morphology. Newly hatched broiler chicks were inoculated with 2 strains (SH23 and SH35) of Salmonella Heidelberg and cecal morphometry, histopathology, electron microscopy, and bacterial counts in the liver and cecum were assessed. The SH23 and SH35 strains resulted in different changes in villi height and crypt depth and inflammatory cell infiltration in the cecum. The SH35 group had higher liver and cecum bacterial cell counts when compared with SH23 strains.

RESUMO.-[Genes associados à patogenicidade deEscherichia coli patogênica para aves (APEC) isoladas de frangos de corte com sintomatologia clínica respiratória.] Os mecanismos de virulência das amostras de Escherichia coli potencialmente patogênicas para aves (APEC) têm sido continuamente estudados e acredita-se ser multifatorial. Certas propriedades são associadas primariamente a amostras virulentas e vêm sendo identificadas em amostras de E. coli isoladas de aves. Neste estudo um total de 61 amostras de E. coli, isoladas de frangos de corte com problemas respiratórios, foram testadas através da Reação em Cadeia da Polimerase (PCR), para a presença dos genes responsáveis pela capacidade de adesão, fimbria P (papC) e fimbria F11 (felA), produção de colicinas (cvaC), presença de aerobactina (iutA), resistência sérica (iss), hemaglutinina temperatura sensível (tsh) e presença de dos antígenos capsulares K1 e K5 (kpsII). O gene iss foi detectado em 73,8%, tsh em 55,7%, iutA em 45,9%, felA em 39,3%, papC em 24,3%, cvaC em 23% e kpsII em 18%.

The current systems of breeding poultry, based on high population density, increase the risk of spreading pathogens, especially those causing respiratory diseases and those that have more than one host. Fowl Cholera (FC) is one such pathogen, and even though it represents one of several avian diseases that should be considered in the differential diagnosis of notifiable diseases that present with sudden death, the pathogenesis and virulence factors involved in FC are still poorly understood. The objective of this study was to investigate twelve genes related to virulence in 25 samples of Pasteurella multocida isolated from FC cases in the southern region of Brazil through the development of multiplex PCR protocols. The protocols developed were capable of detecting all of the proposed genes. The ompH, oma87, sodC, hgbA, hgbB, exBD-tonB and nanB genes were present in 100% of the samples (25/25), the sodA and nanH genes were present in 96% (24/25), ptfA was present in 92% (23/25), and pfhA was present in 60% (15/25). Gene toxA was not identified in any of the samples studied (0/25). Five different genetic profiles were obtained, of which P1 (negative to toxA) was the most common. We concluded that the multiplex-PCR protocols could be useful tools for rapid and simultaneous detection of virulence genes. Despite the high frequency of the analyzed genes and the fact that all samples belonged to the same subspecies of P. multocida, five genetic profiles were observed, which should be confirmed in a study with a larger number of samples.

Eight hundred skin samples from broiler carcasses condemned or downgraded for skin lesions were collected at five processing plants. Histologicall y, 45.25% were cellulitis, 19.00% were atypical fowlpox, 3.25% were dermal squamous cell carcinoma (DSCC), 17.00% were non-specific dermatitis, 0.5% were focal haemorrhages and 0.25% were haemangiomas. Of the samples, 14.75% were histologically normal. Macroscopically, increased thickening of the skin was a frequent finding occurring in all the skin diseases, as well as skin discoloration, dark nodules in feather follicles and crusts. Skin scratches were associated with all of the diseases, except DSCC. Crater-like ulcers occurred in DSCC and fowlpox. Cellulitis was more frequent on the abdomen, fowlpox on the dorsum, DSCC in thighs, and non-specific dermatitis on the dorsum, thighs, legs and breast. It was concluded that macroscopic changes are not specific and examinations at slaughterhouses do not allow classification of broiler skin diseases. Histological examination appears to be an important tool to provide more accurate data.