Veterinary Research Forum

Abstract The accessory gene regulator(agr) operon as a part of the quorum-sensing (QS) system, is responsible for the regulation of numerous virulence factors in Staphylococci. Furthermore, the ability of the opportunistic pathogen, Staphylococcus pseudintermedius to form biofilm is a significant contributor to chronic diseases. Our aim was evaluation of the association between different agr groups and the expression of icaD gene related to biofilm formation among S. pseudintermedius from nasal samples. Fifty nasal swabs were collected from broiler chickens; then phenotypic and molecular tests performed for isolation of S. pseudintermedius from samples and their agr genotype was also investigated. The biofilm production capacity of the isolates was determined using both microtiter plate assay and amplification of icaD gene. S. pseudintermedius was detected in 86.84% of samples. The assessment of agr typing results related that most of the strains (69.70%) were classified in agr group ɪ. The relative frequency of biofilm producing S. pseudintermedius isolates was 75.76% and all of them harbored icaD gene. The expression level of icaD determinant was significantly higher among isolates in agr group ɪ than other agr groups. The results suggest that broiler chickens may act as a reservoir for transmission of S. pseudintermedius to humans which should be considered a potential zoonotic bacterium able to produce different virulence factors like biofilm.

Abstract Cryopreservation has the capacity to extend spermatozoa’s lifespan and viability. In addition, the semen samples can be collected, preserved and stored or sent to distant locations and still be used long after the death of the semen donor. In this study for the vitrification of dog sperm (fresh and swum-up sperm), different cryopreservation mediums on the basis of glycerol, milk and egg yolk were used. Then, all of the samples were vitrified in the liquid nitrogen and thawed at least 48 hr later for re-examination of sperm parameters. The sperm parameters before and after cryopreservation in all groups were compared. It was found that during vitrification process, spermatozoa were damaged by the mechanical blows in centrifugation during swim-up processing, so they had less resistance than fresh semen. The examination of different cryoprotectants revealed that milk has better effects on the cryopreservation of semen than glycerol and egg yolk. With the comparison of the effects of glycerol and egg yolk as cryoprotectants, it was found that glycerol had better effects than egg yolk on the cryopreservation of the semen. In conclusion, milk might be used as a cryoprotectant instead of glycerol for canine sperm cryopreservation.