ABSTRACT Fowl paratyphoid infections are caused by different Salmonella serovars that can affect a wide range of hosts. Due to its complex epidemiology, Salmonella serovar identification is crucial for the development and implementation of monitoring and control programs in poultry farms. Moreover, the characterization of the antimicrobial resistance profiles of Salmonella strains isolated from livestock is relevant to public health because they are a common causative agent of foodborne diseases. The objective of this study was to investigate the presence of Salmonella spp. and to identify the antimicrobial resistance profiles of strains isolated in the midwestern region of São Paulo state, which accounts for the highest production of table eggs in Brazil. For this purpose, 2008 fecal samples were collected on 151 commercial layer farms and submitted to microbiological analyses. Twenty-two serovars were isolated from 80 (52.9%) farms, among which S. Mbandaka and S. Braenderup were the most prevalent. All isolates expressed resistance to at least one of the 23 antimicrobials tested, and the highest resistance rates were determined against streptomycin (93.5%) and sulfonamide (84.6%). Moreover, multidrug resistance was observed in 41% of the isolates and the maximum drug resistance profile was against ten different antimicrobials. Therefore, the identification of Salmonella serovars in poultry production provides epidemiological knowledge to develop prevention and control measures in order to ensure poultry health and to prevent human infection by multiresistant strains.

ABSTRACT Avian pathogenic Escherichiacoli (APEC) virulence mechanism has been continuously studied and it is believed to be multifactorial and because of this, this work aimed to characterize potentially APEC strains isolated from free-range hens. Isolates were submitted to PCR for the detection of virulence genes, which were of high prevalence. In vivo inoculation of day-old chicks revealed that 49 of these strains were of high and intermediate pathogenicity. In addition, isolates were submitted to antimicrobials susceptibility test with the majority of the strains presenting multiresistance. Phylogenetic analysis showed a greater presence of potentially APEC isolates in-group B2. In addition, high heterogeneity was detected among the isolates byXbaI enzyme. Fifteen serogroups were identified, being the O8 the most frequent. These results strengthen the fact that a combination of diverse factors are associated with the pathogenicity APEC strains, as well as to highlight its importance to public health and that free-range hens can act as a reservoirs of potentially zoonoticbacteria.

ABSTRACT In poultry processing plants, disinfectants are often added to pre-chilling water tanks to reduce microbial contamination. The present study aimed at evaluating the effect of five disinfectants (acidified sodium chlorite, alkyl dimethyl benzyl ammonium chloride, chlorine dioxide, peracetic acid, and sodium hypochlorite) on the populations of food quality indicator microorganisms and on Salmonella Enteritidis (SE) in the presence and absence of organic matter. The results showed that chlorine dioxide and sodium hypochlorite did not reduce microbial carcass counts. On the other hand, acidified sodium chlorite, alkyl dimethyl benzyl ammonium chloride and peracetic acid reduced total and fecal coliform counts. Peracetic acid reduced the number of psychrotrophic microorganisms. All products were effective in reducing SE counts only in the absence of organic matter. Acidified sodium chlorite, alkyl dimethyl benzyl ammonium chloride and peracetic acid could be candidates for the replacement of sodium hypochlorite (commonly used in Brazil) in pre-chilling tanks.

In the present study Salmonella spp. was surveyed in four flocks of meat-type quails reared in a farm that also had processing plant on site, located in the region of Bastos, state of São Paulo, Brazil. Meconium samples of one-day-old quail chicks were collected from transport cardboard boxes. Cecal content was collected on days 7, 14, 21, 28 and 35 of rearing. At 36 days of age, birds were slaughtered in the farm's processing plant, where two samples of water from the scalding and the chilling tanks and four carcasses per flock were collected. All samples were examined for Salmonella spp. using traditional bacteriological methods. Salmonella spp. was present in meconium samples of three flocks and in cecal feces of the four flocks. This bacterium was also isolated in the chiller water and in the carcasses of three of the evaluated flocks and in the scalding water of one flock. In this study, S. enterica subspecies enterica 4, 5, 12; S. Corvalis; S. Give; S. Lexington; S. Minnesota; S. Schwarzengrund; S. Rissen and S. Typhimurium were the eight serovars identified.