Characterization of the virulence and resistance factors of Staphylococcus epidermidis associated with treatment failure in osteoarticular infections with orthopedic implants

The microbiological diagnosis of osteoarticular infections associated with implants remains challenging in medical practice. In many cases, the identification of pathogenic agents by traditional microbiological methods using surgically removed tissue samples results in false negatives, especially in patients on previous use of antibiotics and in those in whom the biofilm adhered to the implants concentrates most of the inoculum. These facts are closely associated with high morbidity (with a high rate of severe and disabling sequelae) of osteomyelitis associated with orthopedic trauma, which is increasingly frequent in Brazil due to the high incidence of motorcycle accidents. It is known that S. epidermidis is the pathogen frequently isolated in infections related to orthopedic devices. Its pathogenicity is based on adhesion to surfaces and biofilm production. However, studies with follow-up and clinical outcomes in Brazil are lacking since this infectious agent is considered a commensal contaminant of the skin and mucous membranes. The formation of biofilm directly interferes with surgical medical treatment because, when installed on surfaces of orthopedic implants, it provides resistance to antibiotic therapy and the action of the individual's immune system since sessile microorganisms have intrinsic survival skills, which must be better elucidated so that we can understand the recurrent therapeutic failures in osteomyelitis associated with orthopedic trauma. Thus, it is fundamental to progress in the research of new modalities of microbiological diagnosis, using methods that allow the identification of sessile microorganisms adhered to biofilms through the application of an ultrasonic bath on the removed implants, carrying out molecular studies that will enable the identification of virulence and antimicrobial resistance factors of the causative agents of osteomyelitis and associated with relapse of the infection; and also in the better characterization of the minimum inhibitory and bactericidal concentrations of the antibiotics capable of eliminating the pathogens inside the biofilms. Therefore, this study will have an impact of clinical and microbiological importance since when we use new tools such as the WGS to characterize virulence factors, when we determine the minimum inhibitory concentrations that reach sessile microorganisms, which are protagonists in osteoarticular infections, associating it with the clinical outcome, we will contribute with the provision of more specific diagnoses, therapeutic success, with the reduction of the inappropriate use of antimicrobials that are directly related to the selection of resistant microorganisms and also with the reduction of expenses in the sectors of Orthopedics and Traumatology.