Results of the Surveillance of Tedizolid Activity and Resistance Program: in vitro susceptibility of Gram-positive pathogens collected in 2011 and 2012 from the United States and Europe

In vitro activity of tedizolid against staphylococci isolated from prosthetic joint infections

We determined the MIC and minimum biofilm bactericidal concentration (MBBC) of tedizolid and vancomycin against 97 isolates of Staphylococcus aureus and 74 isolates of Staphylococcus epidermidis associated with prosthetic joint infection. All isolates were vancomycin susceptible in the planktonic state; all staphylococci studied had a tedizolid MIC ≤0.5 μg/mL. The MBBC90 was >32 and >128 μg/mL for tedizolid and vancomycin, respectively.

In Vitro Activities of Tedizolid and Linezolid against Gram-Positive Cocci Associated with Acute Bacterial Skin and Skin Structure Infections and Pneumonia

Tedizolid is a novel, expanded-spectrum oxazolidinone with potent activity against a wide range of Gram-positive pathogens. A total of 425 isolates of Gram-positive bacteria were obtained consecutively from patients with acute bacterial skin and skin structure infections (ABSSSIs) or pneumonia. These isolates included methicillin-susceptible Staphylococcus aureus (MSSA) (n = 100), methicillin-resistant Staphylococcus aureus (MRSA) (n = 100), Streptococcus pyogenes (n = 50), Streptococcus agalactiae (n = 50), Streptococcus anginosus group (n = 75), Enterococcus faecalis (n = 50), and vancomycin-resistant enterococci (VRE) (Enterococcus faecium) (n = 50). The MICs of tedizolid and linezolid were determined by the agar dilution method. Tedizolid exhibited better in vitro activities than linezolid against MSSA (MIC90s, 0.5 versus 2 μg/ml), MRSA (MIC90s, 0.5 versus 2 μg/ml), S. pyogenes (MIC90s, 0.5 versus 2 μg/ml), S. agalactiae (MIC90s, 0.5 versus 2 μg/ml), Streptococcus anginosus group (MIC90s, 0.5 versus 2 μg/ml), E. faecalis (MIC90s, 0.5 versus 2 μg/ml), and VRE (MIC90s, 0.5 versus 2 μg/ml). The tedizolid MICs against E. faecalis (n = 3) and VRE (n = 2) intermediate to linezolid (MICs, 4 μg/ml) were 1 μg/ml and 0.5 μg/ml, respectively. The tedizolid MIC90s against S. anginosus, S. constellatus, and S. intermedius were 0.5, 1, and 0.5 μg/ml, respectively, and the rates of susceptibility based on the U.S. FDA MIC interpretive breakpoints to the isolates were 16%, 28%, and 72%, respectively. Tedizolid exhibited 2- to 4-fold better in vitro activities than linezolid against a variety of Gram-positive cocci associated with ABSSSIs and pneumonia. The lower susceptibilities of tedizolid against isolates of S. anginosus and S. constellatus than against those of S. intermedius in Taiwan were noted.

New developments in the management of severe skin and deep skin structure infections - focus on tedizolid

Tedizolid, a novel oxazolidinone, is approved for treatment of acute bacterial skin and skin structure infections (ABSSSIs). Tedizolid offers several potential advantages over current ABSSSI treatment options. First, tedizolid has a prolonged half-life, which allows for once-daily dosing. Second, tedizolid has broad spectrum activity against Gram-positive organisms including methicillin-resistant Staphylococcus aureus, coagulase-negative staphylococci, and enterococci. Third, tedizolid, available in both intravenous and oral formulations, has high oral bioavailability, allowing for easy oral step-down therapy. Fourth, in patients who have been prescribed selective serotonin reuptake inhibitors or monoamine oxidase inhibitors, tedizolid may have fewer drug interactions than linezolid. Finally, tedizolid may have fewer or comparatively delayed onset side effects than linezolid, including thrombocytopenia and nausea. This review covers the microbiology, pharmacology, mode of action, and pharmacokinetics of tedizolid as well as patient-focused perspectives such as quality of life, patient satisfaction/acceptability, adherence, and uptake and provides expert opinion on the current use of tedizolid for ABSSSIs and potential future therapeutic applications.

Vancomycin in the treatment of methicillin-resistant Staphylococcus aureus - a clinician's guide to the science informing current practice

Clinicians treating an infection assess a patient in terms of disease manifestation, causative organism and available antibiotic options with the aim of devising a therapeutic strategy under the creed of 'first, do no harm'. It is often only when treatment is failing or options are limited, as in the scenario of multidrug-resistant organisms, that consideration is given to the interplay that occurs between the microbe and the host. The emergence of Staphylococcus aureus with reduced susceptibility to vancomycin provides a prime example of these dynamic interactions. This review shall explore these concepts in relation to vancomycin for the treatment of methicillin-resistant S. aureus, with the aim of providing an informed approach to the utilization of this drug.

Profile of tedizolid phosphate and its potential in the treatment of acute bacterial skin and skin structure infections

Tedizolid phosphate is the first once-daily oxazolidinone approved by the United States Food and Drug Administration for the treatment of acute bacterial skin and skin structure infections (ABSSSI). It is more potent in vitro than linezolid against methicillin-resistant Staphylococcus aureus (MRSA) and other gram-positive pathogens causing ABSSSI, even retaining activity against some linezolid-resistant strains. Tedizolid is approximately 90% protein bound, leading to lower free-drug concentrations than linezolid. The impact of the effect of food, renal or hepatic insufficiency, or hemodialysis on tedizolid's pharmacokinetic have been evaluated, and no dosage adjustment is needed in these populations. In animal and clinical studies, tedizolid's effect on bacterial killing is optimized by the free-drug area under the curve to minimum inhibitory concentration ratio (fAUC/MIC). The 200 mg once-daily dose is able to achieve the target fAUC/MIC ratio in 98% of simulated patients. Two Phase III clinical trials have demonstrated the noninferiority of tedizolid 200 mg once daily for 6 days to linezolid 600 mg twice daily for 10 days. In vitro, animal, and clinical studies have failed to demonstrate that tedizolid inhibits monoamine oxidase to a clinically relevant extent. Tedizolid has several key advantages over linezolid including once daily dosing, decreased treatment duration, minimal interaction with serotonergic agents, possibly associated with less adverse events associated with the impairment of mitochondrial protein synthesis (eg, myelosuppression, lactic acidosis, and peripheral/optic neuropathies), and retains in vitro activity against linezolid-resistant gram-positive bacteria. Economic analyses with tedizolid are needed to describe the cost-effectiveness of this agent compared with other options used for ABSSSI, particularly treatment options active against MRSA.

Tedizolid Phosphate: a Next-Generation Oxazolidinone

Treatment of multidrug-resistant Gram-positive infections continues to challenge clinicians as the emergence of new resistance mechanisms outpaces introduction of novel antimicrobial agents. Tedizolid phosphate is a next-generation oxazolidinone with activity against both methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus spp. Tedizolid has consistently shown potency advantages over linezolid against Gram-positive microorganisms including those with reduced susceptibility to linezolid. Of particular significance, minimum inhibitory concentrations of tedizolid appear to be largely unaffected by the chloramphenicol-florfenicol resistance (cfr) gene, which has been implicated in a number of published linezolid-resistant organism outbreaks. Tedizolid phosphate also has been found to have a favorable pharmacokinetic profile allowing for once-daily dosing in both oral and intravenous forms. Potency and pharmacokinetic advantages have allowed for lower total daily doses of tedizolid, compared to linezolid, being needed for clinical efficacy in the treatment of acute bacterial skin and skin structure infections (ABSSSI). The decreased total drug exposure produced may in part be responsible for a decrease in the observed adverse effects including thrombocytopenia. Tedizolid phosphate is currently indicated for the treatment of ABSSSI and under investigation for the treatment of nosocomial pneumonia. Although much of the role of tedizolid remains to be defined by expanding clinical experience, tedizolid is likely a welcomed addition to the mere handful of agents available for the treatment of multidrug-resistant Gram-positive infections.