Effects of Tedizolid Phosphate on Survival Outcomes and Suppression of Production of Staphylococcal Toxins in a Rabbit Model of Methicillin-Resistant Staphylococcus aureus Necrotizing Pneumonia

Abstract

The protective efficacy of tedizolid phosphate, a novel oxazolidinone that potently inhibits bacterial protein synthesis, was compared to those of linezolid, vancomycin, and saline in a rabbit model of Staphylococcus aureus necrotizing pneumonia. Tedizolid phosphate was administered to rabbits at 6 mg/kg of body weight intravenously twice daily, which yielded values of the 24-h area under the concentration-time curve approximating those found in humans. The overall survival rate was 83% for rabbits treated with 6 mg/kg tedizolid phosphate twice daily and 83% for those treated with 50 mg/kg linezolid thrice daily (P ϭ 0.66 by the log-rank test versus the results obtained with tedizolid phosphate). These survival rates were significantly greater than the survival rates of 17% for rabbits treated with 30 mg/kg vancomycin twice daily (P ϭ 0.003) and 17% for rabbits treated with saline (P ϭ 0.002). The bacterial count in the lungs of rabbits treated with tedizolid phosphate was significantly decreased compared to that in the lungs of rabbits treated with saline, although it was not significantly different from that in the lungs of rabbits treated with vancomycin or linezolid. The in vivo bacterial production of alpha-toxin and Panton-Valentine leukocidin, two key S. aureus-secreted toxins that play critical roles in the pathogenesis of necrotizing pneumonia, in the lungs of rabbits treated with tedizolid phosphate and linezolid was significantly inhibited compared to that in the lungs of rabbits treated with vancomycin or saline. Taken together, these results indicate that tedizolid phosphate is superior to vancomycin for the treatment of S. aureus necrotizing pneumonia because it inhibits the bacterial production of lung-damaging toxins at the site of infection.

Community-acquired Pneumonia with Methicillin-resistant Staphylococcus Aureus in a Patient Admitted to the Intensive Care Unit: A Therapeutic Challenge

“…The most common CA-MRSA strain is USA300 [ 3 ]. Its pathogenicity appears to be greatly influenced by the Panton-Valentin-Leukocidin (PVL) toxin that causes leukocyte destruction, and also appears to play a major role in necrotizing pneumonia [ 3 , 4 ]. The 2016 Infectious Disease Society of America recommendations regarding community-acquired pneumonia caused by MRSA or healthcare-associated pneumonia caused by MRSA is to treat with intravenous (IV) vancomycin or linezolid 600 milligrams (mg) twice daily either IV or oral [ 5 ].…”

<p>Tedizolid phosphate for the treatment of acute bacterial skin and skin-structure infections: an evidence-based review of its place in therapy</p>

“…In a rabbit model of MRSA pneumonia, production of α-toxin and Panton–Valentine leukocidin was significantly inhibited when rabbits were treated with tedizolid or linezolid compared with vancomycin 63…”