Methicillin resistant Staphylococcus aureus (MRSA) and Methicillin susceptible Staphylococcus aureus (MSSA) cause dermonecrosis and bacteremia in rats

Abstract

Inserting a contamitaned vascular catheter during the surgical procedure is a factor that might promote biofilm formation on the catheter, possibly leading to bacteremia. The use of experimental models to evaluate organic changes allows a better understanding of infectious processes of multiple organs. The aim of this study was to investigate the influence of methicillin resistance based on bacterial genetic differences in induced infection and subcutaneous catheter colonization, when comparing MRSA and MSSA infections outcomes. Subcutaneous infections with MRSA and MSSA bacterial suspension were performed in 15 Wistar rats divided into three groups as following: saline solution control group, MRSA and MSSA suspension at a 1 x 105 CFU/mL for infection. Subcutaneous polyestilene catheters were surgically inserted into the skin of the animals before the infection. After 72 hours, subcutaneous implants, heart, spleen and kidneys were harvested and evaluated. The animals presented a typical auto resolutive case of bacteremia. The catheters and organs presented the same S. aureus isolate genotype as inoculated with evident biofilm formation. Our results showed both MRSA and MSSA bacteremia can compromise multiple organs within 72 hours of infection.