Staphylococcus spp. present in peripheral intravenous catheters, their virulence factors and antibiotic resistance

• Autor(a) principal: Oliveira, Vânia Silva
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/26900
• topic: Peripheral intravenous catheter; Staphylococcus spp; Virulence factors; Antibiotic resistance

The insertion of a peripheral intravenous catheter (PIVC) is one of the most frequently performed invasive procedures in the hospital setting. However, PIVCs usually fail before the completion of intravenous treatment and upon insertion the risk of infection increases exponentially. There are few studies evaluating the contamination of this vascular medical device and characterizing the associated microorganisms regarding the production of virulence factors and antimicrobial resistance. A total of 110 PIVCs ends were analyzed using the Maki et al. methodology and microorganisms were identified. The Staphylococcus spp. were subsequently studied for the antimicrobial susceptibility profile by disc diffusion method and based on the cefoxitin phenotype were further classified into strains resistant to methicillin. A screening for the mecA gene was also done by PCR and MICvancomycin as determined by E-test, proteolytic and hemolytic activity on Skim milk 1% plate and blood agar, respectively. The biofilm formation was evaluated on microplate reading through iodonitrotetrazolium chloride 95% (INT). About 30% of PIVCs were contaminated and the most prevalent genus was Staphylococcus spp., 48.8%. This genus presented resistance to penicillin (91%), erythromycin (82%), ciprofloxacin (64%) and cefoxitin (59%). Thus, 59% of strains resistant to methicillin were detected. We detected the mecA gene in 82% of the isolates tested. Regarding the virulence factors, 36.4% presented hemolysis and 22.7% hemolysis, 63.6% presented a positive result for the production of proteases and 63.6% presented a biofilm formation capacity. About 36.4% were simultaneously resistant to methicillin and showed expression of proteases and/or hemolysins, biofilm formation and MIC for vancomycin greater than 2μg/mL. Thus, our study evidenced contamination of PIVCs mainly by Staphylococcus spp., with high pathogenicity demonstrated by the presence of virulence factors, as well as resistance to antibiotics. The production of virulence factors allows to strengthen the attachment and the permanence in the catheter. When we also associate antimicrobial resistance, the treatment of the related infections becomes more difficult and the scarce treatment options. These data should be considered by health professionals who must take preventive measures to minimize the risk of contamination and consequent reduction of infections related to the use of peripheral intravenous catheters