Succesfull empirical antibiotic therapy for septic knee arthritis.

Resumen

BACKGROUND:

Septic knee arthritis is a traumatological emergency condition whose diagnostic or therapeutic delay may involve joint destruction and high morbidity and mortality. The epidemiology knowledge of this infection is a key factor to establish the best empirical antibiotic treatment. The literature supports the combination of 2 antibiotics with appropriate characteristics, such as good joint diffusion.

OBJECTIVES:

The aim of the study was to establish an effective empirical antibiotic therapy according to the microbiological results obtained in our patients with osteoarticular knee infection (septic arthritis or infected total knee arthroplasty). We analyzed the epidemiology, prevalence and antimicrobial sensitivity pattern

STUDY DESIGN & METHODS:

A descriptive retrospective study was performed between January 2011 and January 2021 in a local Hospital. The collected data included gender, age, arthroplasty carrier, diabetes mellitus and immunocompromised condition; microbiological variables included infecting microorganisms, infection type (mono or polymicrobial culture) and antibiotic susceptibility. Inclusion criteria: patients with knee infection and positive sample of synovial fluid. Exclusion criteria: patients with negative cultures

DISCUSION:

The etiology of our sample was fundamentally gram positive. Although S. aureus is described as the most frequent etiology, in our population S. epidermidis had a similar frequency. MRSA was more frequent than in other studies. Based on our results, the most effective antibiotics were vancomycin, linezolid, trimethoprim/sulfametoxazole, rifampicin, and third and fourth generation cephalosporin.

To facilitate the choice of empirical antibiotic therapy, different countries have studied the most frequent microorganisms in their environment, and propose different recommendations; for example, Italy recommends teicoplanin and ceftriaxone; London oxacillin (or clindamycin or second or third generation cephalosporin, if allergy) + fusidic acid or gentamicin. On suspicion of MRSA, they use second or third generation cephalosporin and vancomycin. According to our results, this last guideline would be useful in our patients.

CONCLUSIONS

Considering the high rate of methicillin - resistant Staphylococcus spp, the recommended empirical antibiotic therapy in our centre is vancomycin and cefepime for patients with normal renal function. This would have been effective in 97,8% of our episodes with positive cultures.