Hamilton Luiz de Souza Moraes

Antibiotic resistance in Salmonella Enteritidis isolated from broiler carcasses

Eighty Salmonella Enteritidis strains isolated from broiler carcasses between May 1995 and April 1996 in the State of Rio Grande do Sul, Brazil, were tested for antibiotic susceptibility using the disk diffusion method. Resistance to colistin, novobiocin, erythromycin and tetracycline was observed in 100% of the isolates. The strains showed intermediate resistance at different levels to kanamycin (1.25%), enrofloxacin (3.75%), neomycin (3.75%), fosfomycin (20%), sulphonamides (86.25%) and nitrofurantoin (90%). Resistance to ciprofloxacin, norfloxacin, gentamicin, polymyxin B, sulphametrim and sulphazotrim was not found. Since resistance to antibiotics especially those introduced in the last decades, was detected, it is recommended that their use must be based on the results of resistance tests or minimum inhibitory concentration tests.

Occurrence and Characterization of Campylobacter in the Brazilian Production and Processing of Broilers

Abstract Twenty-two commercial broiler flocks and their carcasses, totaling 546 samples (450 collected from a poultry farm and 96 from a slaughterhouse), were surveyed for the presence of Campylobacter. The positive results for Campylobacter among the analyzed samples were homogeneous, yielding 81.8% for cecal droppings, 80.9% for feces, and 80.4% for cloacal swabs. Pre-enrichment and direct plating showed that 77.85% and 81.8% of cloacal swabs, respectively, were positive for Campylobacter compared to 99.0% and 97.9% of carcasses testing positive with the pre-enrichment and direct plating methods. The Campylobacter count averaged 7.0 log10 colony-forming units (CFU)/g in cecal droppings, 5.15 log10 CFU/carcass after defeathering, and 4.24 log10 CFU/carcass after chilling. The samples were identified by the API Campy system as Campylobacter jejuni subsp. jejuni (68.8%), Campylobacter coli (8.3%), Campylobacter jejuni subsp. doylei (6.3%), Campylobacter upsaliensis (4.2%), and Campylobacter fetus subsp. fetus (2.1%). The analyzed broiler flocks were positive for Campylobacter in 81.8% of the cases, thus characterizing the occurrence of this pathogen in a broiler-producing region in southern Brazil. These results highlight the importance of programs targeted at the reduction of Campylobacter in poultry products, in order to minimize the risks for consumers. Abbreviations: CFU = colony-forming units; mCCDA = modified charcoal cefoperazone deoxycholate agar; TTC = triphenyl tetrazolium chloride Nota de Investigación—Ocurrencia y caracterización de Campylobacter en pollos de engorde procesados y en producción. Para evaluar la presencia de Campylobacter, se realizó una encuesta en 22 lotes comerciales de pollos de engorde y sus canales, con un total de 546 muestras de las cuales 450 fueron tomadas de una granja de pollos y 96 de la planta de proceso. Entre las muestras analizadas, los resultados positivos para Campylobacter fueron homogéneos, encontrándose un 81.8% en las heces cecales, 80.9% en las heces y 80.4% en los hisopos cloacales. Los resultados obtenidos mediante pre-enriquecimiento y siembra directa mostraron una positividad para el Campylobacter del 77.85% y 81.8%, respectivamente, para los hisopos cloacales, comparado con el 99.0% y 97.9% de positividad para las canales. Los promedios de los recuentos de Campylobacter fueron 7.0 log10 unidades formadoras de colonia (UFC) por gramo en las heces cecales, 5.15 log10 UFC en las canales después del desplume, y 4.24 log10 UFC para las canales después del enfriamiento. Mediante el sistema API Campy, las muestras fueron identificadas como Campylobacter jejuni subsp. jejuni (68.8%), Campylobacter coli (8.3%), Campylobacter jejuni subsp. doylei (6.3%), Campylobacter upsaliensis (4.2%), y Campylobacter fetus subsp. fetus (2.1%). Los lotes de pollos analizados fueron positivos a Campylobacter en el 81.8% de los casos, caracterizando de esta manera la ocurrencia de este patógeno en la región del sur del Brasil productora de pollos. Estos resultados enfatizan la importancia de establecer programas enfocados a la reducción del Campylobacter en los productos avícolas, con el objeto de disminuir el riesgo para los consumidores.

Diagnosis of skin lesions in condemned or downgraded broiler carcasses — a microscopic and macroscopic study

Eight hundred skin samples from broiler carcasses condemned or downgraded for skin lesions were collected at five processing plants. Histologically, 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.

Effects of Probiotics and Maternal Vaccination on Salmonella Enteritidis Infection in Broiler Chicks

Abstract The effects of probiotics and maternal vaccination with an inactivated Salmonella Enteritidis (SE) vaccine on day-old chicks challenged with SE were evaluated. A 2 × 3 factorial arrangement was used (with or without probiotics; breeders nonvaccinated, vaccinated intramuscularly, or vaccinated intraperitoneally). Three trials were conducted in isolation cabinets and SE challenge was different between trials. The number of SE organisms per chick and the time interval between housing and introduction of seeder birds (hereafter called challenge) were 1.6 × 108 and 1 hr (Trial I), 1.8 × 106 and 12 hr (Trial II), and 1.2 × 104 and 24 hr (Trial III). SE recovery was assessed in ceca and liver at 3, 5, and 7 days postchallenge, and the number of colony-forming units (CFU) in ceca was evaluated at 5 and 7 days postchallenge. The number of SE (log CFU) in the ceca reduced 0.56 log (from 7.59 to 7.03) and 1.45 log (7.62 to 6.17) because of the treatment with probiotics in Trials II and III, respectively. The greater reduction in Trial III indicates the importance of the early use of probiotics on the prevention of SE infection. Treatment with probiotics resulted in a smaller number of SE-positive livers after 5 days postchallenge on Trial III. Although there was no significant effect of maternal vaccination on the number of SE CFU in the ceca, a significant effect of maternal vaccination on the SE CFU was observed in the liver, but not in the ceca at 5 days after challenge.

Presence of avipoxvirus DNA in avian dermal squamous cell carcinoma

Dermal squamous cell carcinoma (DSCC; avian keratoacanthoma) is a neoplastic skin lesion of broiler chickens of unknown aetiology. In previous studies, the possibility of the involvement of pox viruses in the cause of DSCC was considered. In this work, a sensitive and specific nested polymerase chain reaction (PCR) protocol was developed that could amplify a 419 base pair DNA fragment of fowlpox virus with a detection limit of less than one infectious unit. Fowlpox virus DNA was always detected in skin samples with fowlpox lesions while it was not detected in samples of unrelated diseases such as cowpox, Mareks disease or infectious laryngotracheitis. Some macroscopically normal skin samples from vaccinated and non-vaccinated birds also produced PCR-positive results, corroborating previous studies on the possibility that a latent or chronic form of fowlpox occurs. Fowlpox virus DNA was consistently detected from DSCC skin lesions, and this finding is discussed.

Behavior of Salmonella heidelberg and Salmonella enteritidis strains following broiler chick inoculation: evaluation of cecal morphometry, liver and cecum bacterial counts and fecal excretion patterns

Over the years, Salmonella Heidelberg (SH) has gained prominence in North America poultry production and in the poultry production of other countries. Salmonella Heidelberg has been isolated and reported from poultry and poultry products in Brazil since 1962, whereas Salmonella Enteritidis (SE) has only emerged as a serious problem in poultry and public health since 1993. These strains of Salmonella can cause intestinal problems in newly hatched chicks, and infection may persist until adulthood. Upon slaughter of chickens, Salmonella can contaminate carcasses, a condition that poses a threat to human health. The aim of this study was to compare the fecal excretion of Salmonella Enteritidis and Salmonella Heidelberg in newly hatched chicks (orally inoculated with 105ufc/mL each) until 20 days of age. In addition, the ratio of cecal villus height:crypt depth (morphometry) and liver and cecum cell counts was analyzed in chicks ranging from 0 to 3 days of age and infected with these two Salmonella strains. One hundred seventeen chicks were separated into one of three experimental groups: a control group, an SE-infected group and an SH-infected group. Eight chicks per group were euthanized at 6, 12 and 72 hours post-inoculation (pi) to allow for Salmonella isolation from the liver and cecum and for the collection of the cecum for villi and crypt analysis. Other birds were allowed to mature to 20 days of age and cloacal swabs were taken at 2, 6, 13 and 20 days pi to compare the fecal excretion of inoculated strains. The Salmonella Enteritidis group had a higher number of cells excreted during the trial. Both strains were isolated from the liver and cecum by 6h pi. At 12h pi the Salmonella Heidelberg group had high cell counts in the cecum. No difference was found in liver cell counts. Both strains showed lower villus height:crypt depth ratio than the control group post-infection.

Virulence Factors of Avian Pathogenic Escherichia coli Isolated from Broilers from the South of Brazil

SUMMARY. Sixty-three Escherichia coli strains isolated from broilers with respiratory problems were examined for virulence factors, hemolysin synthesis ability, motility, hemagglutination capacity, operon pap presence, colicin production, and serum resistance. The capacity to hemagglutinate guinea pig erythrocytes was found in 53 (84.1%) of the samples, but only 30 (47.6%) agglutinated chicken erythrocytes. d-mannose-sensitive hemagglutination against guinea pig erythrocytes was found in 19 (30.2%) samples and against chicken erythrocytes, in 15 (23.8%) samples, whereas the d-mannose-resistant hemagglutination with guinea pig erythrocytes was found in 34 (54%) samples, and 13 of these (20.6%) showed this characteristic against chicken erythrocytes. Operon pap, P fimbria codifier, was detected in 26 samples in a total of 34 d-mannose-resistant samples. Colicin production was observed in 55 (87.3%) of the strains, and 41.8% presented V colicin production. Of the samples analyzed, 56 (88.9%) presented serum resistance, six (9.5%) were intermediate, and only one (1.6%) was sensitive to the action of the complement. The diversity of virulence profiles detected in the samples in this study explains in part the multifactorial characteristics of avian colibacillosis.

Detection of virulence-associated genes of Pasteurella multocida isolated from cases of fowl cholera by multiplex-PCR

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.

Genes associated with pathogenicity of avian Escherichia coli (APEC) isolated from respiratory cases of poultry

ABSTRACT .- Rocha A.C.G.P., Rocha S.L.S., Lima-Rosa C.A.V., Souza G.F., MoraesH.L.S., Salle F.O., Moraes L.B. & Salle C.T.P. 2008. Genes associated withpathogenicity of avian Escherichia coli (APEC) isolated from respiratory cases ofpoultry. Pesquisa Veterinaria Brasileira 28(3):183-186. Centro de Diagnostico e Pesquisaem Patologia Aviaria, Departamento de Medicina Animal, Faculdade de Veterinaria,Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 8824, Porto Alegre,RS 91540-000, Brazil. E-mail: ana.crocha@terra.com.brThe virulence mechanisms of avian pathogenic Escherichia coli (APEC) have beencontinually studied and are believed to be multi-factorial. Certain properties are primarilyassociated with virulent samples and have been identified in avian isolates. In this studya total of 61 E. coli , isolates from chicken flocks with respiratory symptomatology, wereprobed by Polimerase Chain Reation (PCR) for the presence of genes responsible forthe adhesion capacity, P fimbria (

Infectious Bursal Disease: Evaluation of Pathogenicity of Commercial Vaccines from Brazil in Specific Pathogen Free Chichens

Infectious Bursal Disease (IBD) is a chicken disease economically important for the poultry industry in function of the immune depression that it causes. Disease control is made with different vaccines and vaccination programs. In present work, the pathogenicity of 3 intermediate vaccines (I1, I2 and I3), 2 intermediate more pathogenic (IP1 and IP2) and 3 vaccines containing strong virus (F1, F2 and F3) was evaluated. Birds vaccinated with IP1, IP2, F1, F2 and F3 showed significantly lower bursa size in relation to control animals and animals vaccinated with I1, I2 and I3. On the other hand, vaccines I1 and I3 induced antibody titers higher than the control and lower than I2, IP1, IP2, F1, F2 and F3. Histological scores showed that vaccines I1, I2 and I3 induced similar injury degree, although I2 and I3 were not different from the control, whereas I1 was slightly different. Strong vaccines induced more pronounced lesions than the other tested vaccines. These findings suggest that strong vaccines are able to cause severe bursal injuries. However, bursometry and relative weight of the bursa of Fabricius wereconsidered inadequate to evaluate vaccine pathogenicity. Moreover, strong vaccines induced higher antibody titers than the other vaccines, although some intermediate vaccines induced similar titers.