This work reports the results of analyses of three complete mycoplasma genomes, a pathogenic (7448) and a nonpathogenic (J) strain of the swine pathogen Mycoplasma hyopneumoniae and a strain of the avian pathogen Mycoplasma synoviae; the genome sizes of the three strains were 920,079 bp, 897,405 bp, and 799,476 bp, respectively. These genomes were compared with other sequenced mycoplasma genomes reported in the literature to examine several aspects of mycoplasma evolution. Strain-specific regions, including integrative and conjugal elements, and genome rearrangements and alterations in adhesin sequences were observed in the M. hyopneumoniae strains, and all of these were potentially related to pathogenicity. Genomic comparisons

Bacteriophages isolated from free-range chickens were tested as a therapeutic agent for reducing the concentration of Salmonella enterica serovar Enteritidis phage type 4 (S. Enteritidis PT4) in caeca of broilers. One-day-old broilers infected with S. Enteritidis PT4 by a seeder bird method were orally treated on the seventh day of age with a mixture of 10(11) plaque-forming units of each of three bacteriophages. Five days after treatment the bacteriophage-treated group showed a reduction of 3.5 orders of magnitude on colony-forming units of S. Enteritidis PT4 per gram of caecal content. Samples collected at 10, 15, 20 and 25 days after treatment revealed that treated birds still had lower colony-forming units of S. Enteritidis PT4 per gram of caecal content. These data gave us compelling evidence that a mixture of bacteriophages may be efficacious in reducing S. Enteritidis PT4 concentration in broilers' caeca and therefore reducing contamination of poultry products by this food-borne pathogen.

A Mycoplasma synoviae (MS)-free flock of broiler breeders was housed for brooding and rearing on an MS endemic farm. PCR revealed that the flock became infected within nine weeks. At 22 weeks the flock was transferred to a clean and disinfected house on a previously depopulated farm. The birds were then subjected to three treatments with fluoroquinolones due to recurrent Escherichia coli peritonitis and from the 32 weeks of age they received 600 ppm of oxytetracycline hydrochloride continuously in the feed. Monitoring by PCR showed a decrease in MS positive birds after 34 weeks of age and MS may have been eradicated as judged by consistent negative results in PCR. We conclude that intensive antibiotic treatments supported by adequate biosecurity could clear MS from infected broiler breeders.

Reducing Salmonella contamination in poultry is of major importance to prevent the introduction of this microorganism into the food chain. Salmonellae may spread during storage time (shelf life) whenever pre-harvest control fails or post-harvest contamination occurs. Therefore, preventive measures should also be used in the post-harvest level of poultry production in order to control salmonellae. Chicken skin samples were experimentally contaminated by immersing whole legs (thighs and drumsticks) in a suspension containing 10(6) colony forming units per milliliter (CFU/mL) of Salmonella Enteritidis phage type 4 (SE PT4) at the slaughter day. One day later, samples from one group were immersed in a suspension pool containing 10(9) CFU/mL of each of three wild salmonella-lytic bacteriophages previously isolated from feces of free-range chickens. Salmonella counting was performed at three-day intervals in the chicken legs stored at 5°C and showed a significant reduction (P<0.05) of SE PT4 in bacteriophage-treated cuts on days 3, 6 and 9 post-treatment. These findings suggest that the use of bacteriophages may reduce SE PT4 in chicken skin. Further studies are encouraged and might demonstrate the potential of this approach as an efficient and safe technique to be routinelly used for Salmonella control in chicken products

Mycoplasma gallisepticum- or M. synoviae-challenged chickens were monitored with serological assays (serum plate agglutination, hemagglutination inhibition, and enzyme-linked immunosorbent assay) and polymerase chain reaction (PCR). The tracheal swabs from M. gallisepticum-challenged chickens received three different treatments (phosphate-buffered saline [PBS], Frey's broth, or 10 mM Tris-HCl/250 mM ethylenediaminetetraacetic acid/ 2.5% sodium dodecyl sulfate [STE]) prior to DNA purification. A nonphenolic method for DNA extraction was utilized. The best PCR results were obtained with PBS swab treatment. The nonphenolic method for DNA extraction was compared with a phenolic method in an experiment with tracheal swabs from M. synoviae-challenged chickens and commercial flocks. Both methods gave comparable results.