Produção de biofilme na presença de agentes antimicrobianos e potencial de virulência para Caenorhabditis elegans de diferentes biótipos de Staphylococcus haemolyticus isolados de sangue

• Autor(a) principal: Karam, Bruna Ribeiro Sued
• Data de Publicação: 2018
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/8519
• topic: Staphylococcus haemolyticus; Biofilm; Caenorhabditis elegans; Vancomycin; Antimicrobial multiresistence; Staphylococcus haemolyticus; Biofilme; Caenorhabditis elegans; Vancomicina; Multirresistência; Estafilococos; Aderência bacteriana; Biofilme; Vancomicina; Staphylococcus haemolyticus; CNPQ::CIENCIAS BIOLOGICAS::MICROBIOLOGIA

Coagulase-negative staphylococci (SCN) are found in the skin and mucous membranes of humans and other animals, since some species are a constituent part of the normal flora of these same sites, which may constitute a reservoir for SCN. Staphyloccus haemolyticus is the second most frequent species of human blood cultures, and is frequently associated with antibiotic resistance. The present study aimed the isolation, identification, the resistance profiles to antimicrobial agentes and analysis of virulence factors of S. haemolyticus isolates. MALDI-TOF MS was used in to identify the species. The antimicrobial resistance profiles were detrmined by the disk diffusion test and MIC determination (oxacillin, vancomycin, linezolid, moxifloxacin and teicoplanin). The capacity of the biofilm formation was investigated by testing the Congo Red agar and adhesion assays abiotic surfaces (glass and polystyrene) in the presence and absence of antimicrobial in addition to the PCR icaA, fbp, atl and aap genes. The influence of exogenous enzymes on preformed biofilms was performed with Proteinase K and DNAse treatment. The lethality assays were performed using nematodes Caenorhabditis elegans. The results demonstrated that 25% of the samples were identified as S. haemolyticus. All isolates were multidrug resistance, oxacillin-resistant and vancomycin-sensitive, 32% were linezolid-resistant, 88% were moxifloxacin-resistant and 4% were teicoplanin-resistant. The presence of the icaA gene was detected in 60% of the samples, the fbp and atl genes in 96% of the isolates and the aap gene was detected in 76%. Although most of the samples showed the ability to produce slime and/or biofilm both in the absence and presence of antimicrobials, no correlation was observed with the presence of the icaA gene emphasizing the multifactor nature of the biofilm production. Treatment with Proteinase K and DNAse reduced the intensity of the biofilm formed at different levels to 72% and 60% of the samples respectively. High levels (≤ 90%) of worm mortality were observed within 5 days of infection. Both specific antimicrobial resistance mechanisms, as well as the overcoming of protective barriers, such as bacterial biofilms, need to be considered for the development of new antibacterial therapies. The increase in the number of cases of infections and the multifactorial aspects that favor the pathogenicity of S. haemolyticus should continue to be investigated, since the dissemination of multiresistant microorganisms in the hospital environment has become a growing challenge for public health.