Veterinary Research Forum

The effects of agr -genotype on biofilm forming ability in Staphylococcus pseudintermedius isolates from broiler chickens

Articles in Press

Document Type : Original Article

Authors

Sahar Nouri Gharajelar 1
Pariya Heasri 2
Masoumeh Firouzamandi 3
Roghaiyeh Akbari 2

1 Department of Pathobiology, Faculty of Veterinary Medicine, Tabriz University, Tabriz, Iran.

2 Master Student of veterinary bacteriology, Faculty of Veterinary Medicine, University of Tabriz, Tabriz,

3 Department of Pathobiology, Faculty of Veterinary Medicine, University of Tabriz, P.O. Box: 5166614779, Tabriz, Iran.

10.30466/vrf.2025.2053976.4671
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.

Keywords

Staphylococcus pseudintermedius
broiler chicken
agr group
biofilm
icaD gene
Subjects
Veterinary Research Forum

Articles in Press, Accepted Manuscript
Available Online from 25 June 2026

  • Receive Date 20 February 2025
  • Revise Date 11 August 2025
  • Accept Date 15 November 2025

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