WIGNEY JÚNIOR CARVALHO GONZAGA
Dados de Conclusão:
COORIENTADOR: Professor Doutor Esteban Nicolás Lorenzón
Resumo:
Staphylococcus pseudintermedius is a commensal organism found on the skin and mucous membranes of dogs and is considered the most frequently isolated opportunistic pathogen from clinical canine samples. This species has a variety of virulence and resistance factors, including biofilm production. Due to the significance of infections caused by this bacterium in both animal and human health, further studies related to resistance and virulence are necessary. This study aims to evaluate the biofilm production of S. pseudintermedius isolated from the ocular surface of dogs with ophthalmopathies and to investigate the presence of genes involved in the formation of this mechanism. The study included 63 isolates phenotypically identified as S. pseudintermedius. Among these, 49.2% (31/63) did not produce biofilm, while 50.8% (32/63) were biofilm producers. Of the biofilm producers, 71.9% were weak producers (23/32), 25% were moderate (8/32), and 3.1% were strong biofilm producers (1/32). Methicillin-resistant S. pseudintermedius (3/63) produced biofilm, with two strains being moderate producers and one strain being a weak producer. Additionally, multidrugresistant isolates (36/63) could produce biofilm at varying intensities. Entropion was the disease where the highest number of isolates exhibited biofilm production, followed by dry keratoconjunctivitis. Entropion, presented a number of isolates with moderate biofilm production (4/8) and weak production (4/8), while keratoconjunctivitis sicca isolates were moderate (2/5) and weak producers (3/5). One strong biofilm-producing strain was found in an animal with chalazion. Of the 63 isolates phenotypically classified as S. pseudintermedius, 42.8% (27/63) possessed the nuc gene for this species. The icaA and icaD genes were detected concomitantly in 44/63 solates (68.2%), while the icaD gene alone was found in 2 isolates (3.2%), and none of these genes were detected in 17/63 (26.9%). When observing the presence of these genes in genetically identified isolates, 25.9% (7/27) did not carry icaA and icaD, and 74.1% (20/27) had operons for both genes. Finally, the Kappa coefficient was calculated to evaluate the agreement between biofilm production observed in phenotypic and genotypic tests. The agreement was weak (Kappa = 0.1046). The isolates of S. pseudintermedius demonstrated resistance to commonly used antimicrobials and behaved as significant biofilm producers. The phenotypically and genetically identified isolates exhibited biofilm production at varying intensity levels. Additionally, the presence of the icaA and icaD genes, which are crucial for biofilm production, was observed. The agreement between the tests was weak, which shows that other important genotypic markers may be related to this production.
![]() |
BIBLIOTECA WEB DA UFJ |