| Congresso Brasileiro de Microbiologia 2023 | Resumo: 1063-2 | ||||
Resumo:Staphylococcus pseudintermedius is a commensal bacterium and opportunistic pathogen of dogs. It is responsible for various infections, including pyoderma, surgical site infections (SSI), and medical device-related infections. Although uncommon, the zoonotic transmission of this pathogen has been increasingly reported, mainly as healthcare-associated infection (HAI). It poses a public health problem, especially after the emergence of methicillin-resistant S. pseudintermedius (MRSP) strains, which further limits treatment options. Galleria mellonella is an alternative model used to study the antimicrobial potential, the virulence of microorganisms, and the activation of the immune response. This study represents the first description of G. mellonella as a model for Staphylococcus pseudintermedius infection. Survival curves were conducted by using three groups of G. mellonella larvae. One group of larvae was inoculated with a standardized concentration of MRSP (0.4 absorbance at 630 nm), which was isolated from dog dermal secretion with pyoderma. Two control groups were simultaneously conducted: one composed by larvae inoculated with sterile saline and the another by non-inoculated larvae. All groups were incubated at 37 °C for 15 days. Daily evaluation of phenotypic parameters, such as larvae motility, melanization and mortality were registered. Morphological changes in the larvae and mortality began on the first day of infection and increased over time. By the 15th day of infection, there was an average of only one surviving larva, corresponding to 90 % of mortality (p<0,0001 - Graph 1). Also, the invertebrate host defense cells density (hemocytes) and the evolution of bacterial load by counting of Colony Forming Units (CFU) were also daily performed. S. pseudintermedius load decreased while hemocytes counting increased overtime, suggesting that the insect’s cellular immune response was able to hinder this pathogen (p=0,2). This is the first report of the successful interaction between G. mellonella and animal-borne staphylococcal species. Altogether, these results prove that G. mellonella is an alternative model of infection that will contribute to the understanding of S. pseudintermedius pathogenesis. Finally, it can open doors to the investigation of new treatment approaches. Palavras-chave: Bacteria, Gram positive cocci, Survival curve, Invertebrate model Agência de fomento:Conselho Nacional de Desenvolvimento Científico e Tecnológico (PIBIC-CNPq-UFF, Brazil); Fundação de Amparo à Pesquisa no Estado do Rio de Janeiro, Brazil, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Brazil | |||||