| Congresso Brasileiro de Microbiologia 2023 | Resumo: 397-1 | ||||
Resumo:Staphylococcus spp. are ubiquitous bacteria in the environment and the normal microbiome of various animals. Even though these species act as commensal microorganisms, staphylococci can also cause opportunistic infections. Staphylococcus pseudintermedius is important in companion animals since they are the most prevalent species causing pyoderma, post-surgical, and medical device-related infections. The species’ pathogenicity is intimately associated with their potentially produced virulence factors, like biofilms. This extracellular matrix can provide resistance to the embedded microorganisms. Moreover, the environment can modulate the biofilm production. Therefore, it is essential to understand how external factors modulate biofilm to better comprehend the pathogenicity and virulence of staphylococci of canine origin. Hence, this study aimed to qualitatively and quantitatively evaluate the biofilm formation and composition of methicillin-resistant (MRSP) and methicillin-susceptible (MSSP) S. pseudintermedius samples when subjected to two different types of stress: 1) temperature and 2) osmotic stress. The staphylococci isolates were obtained from a previous study of our laboratory group in 2016 from canine atopic infections. Sixteen MRSP and nine MSSP isolates of S. pseudintermedius were randomly chosen from the laboratory collection (n = 25). Stepanovic et al. (2007) protocol evaluated biofilm formation and the strain ED99 (strong biofilm producer) served as a positive control. The temperature effect was evaluated by incubating inoculated microplates at 30, 37, and 42 ºC. For assessment of the effect of osmotic stress, the inoculated microplates were grown in TSB culture medium and TSB supplemented with 1% glucose (TSBglu) or 4% NaCl (TSBNaCl) at 37 ºC. The influence tests were conducted in static conditions for 24h and executed in three technical replicates and triplicates. Normality tests were evaluated by the Shapiro-Wilk test. For normally distributed samples, statistical analyses were assessed by one-way ANOVA, followed by Tukey’s multiple comparison test. In contrast, for non-normally distributed samples, the Kruskal-Wallis test, followed by Dunn’s multiple comparison test, was used (p < 0,05). All samples were able to form biofilm. Most were strong biofilm producers in every condition except for one MRSP isolate classified as a moderate producer at 30 ºC. The biofilm production at 42 ºC decreased compared to 37 and 30 ºC. In contrast, growth in TSBNaCl significantly increased biofilm formation when juxtaposed with TSB and TSBglu. In conclusion, this study observed that environmental factors could modulate strains of Small Animal Practice importance. Thus, more studies are necessary to understand better the environment's regulation in the biofilm of the S. pseudintermedius specie. Palavras-chave: biofilm formation, external factors, osmotic stress, Staphylococcus pseudintermedius, temperature Agência de fomento:Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – CAPES | |||||