Assessment of telavancin minimal inhibitory concentrations by revised broth microdilution method in phase 3 complicated skin and skin-structure infection clinical trial isolates

Antistaphylococcal discovery pipeline; where are we now?

The serious spread of antibiotic-resistant Staphylococcal aureus strains is alarming. This is reflected by the measures governments and health-related bodies are offering to ease antibiotic drug development. Finding new active agents, preferably with novel mechanism of action, or even finding new targets for drug development are essential. In this review, we summarize the current status of novel antistaphylococcal agents undergoing clinical trials. We mainly discuss antistaphylococcal small molecules and peptides in the text with a special focus on their chemistry, while antistaphylococcal immunotherapy (antibodies) are mentioned in a summative table. This review shall serve as a summary that influences future synthetic efforts in the antistaphyloccocals development field.

Antibacterial activity of recently approved antibiotics against methicillin-resistant Staphylococcus aureus (MRSA) strains: A systematic review and meta-analysis

Background

Methicillin-resistant Staphylococcus aureus (MRSA) infections are considered an important public health problem, and treatment options are limited. Accordingly, in this meta-analysis, we analyzed published studies to survey in vitro activity of recently approved antibiotics against MRSA isolates.

Methods

We searched electronic databases; PubMed, Scopus, and Web of Science to identify relevant studies (until November 30, 2020) that have focused on the in vitro activity of telavancin, dalbavancin, oritavancin, and tedizolid against MRSA isolates. Statistical analyses were conducted using STATA software (version 14.0).

Results

Thirty-eight studies were included in this meta-analysis. Overall in vitro activity of tedizolid on 12,204 MRSA isolates was 0.250 and 0.5 µg/mL for MIC₅₀ and MIC₉₀, (minimum inhibitory concentration at which 50% and 90% of isolates were inhibited, respectively), respectively. The overall antibacterial activity of dalbavancin on 28539 MRSA isolates was 0.060 and 0.120 µg/mL for MIC₅₀ and MIC₉₀, respectively. The overall antibacterial activity of oritavancin on 420 MRSA isolates was 0.045 and 0.120 µg/mL for MIC₅₀ and MIC₉₀, respectively. The overall antibacterial activity of telavancin on 7353 MRSA isolates was 0.032 and 0.060 µg/mL for MIC₅₀ and MIC₉₀, respectively. The pooled prevalence of tedizolid, telavancin, and dalbavancin susceptibility was 100% (95% CI: 100–100).

Conclusion

Telavancin, dalbavancin, oritavancin, and tedizolid had potent in vitro activity against MRSA isolates. The low MICs and high susceptibility rates of these antibiotics recommend a hopeful direction to introduce useful antibiotics in treating MRSA infections in the future.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12941-022-00529-z.

VISA-Daptomycin non-susceptible Staphylococcus aureus frequently demonstrate non-susceptibility to Telavancin

Telavancin was evaluated against S. aureus isolates with reduced susceptibility to other antimicrobial agents using two broth microdilution methods and Etest® strips. The three methods provided comparable results. Differences in telavancin susceptibility versus non-susceptibility were noted mainly in the VISA-daptomycin non-susceptible group of isolates. In this group the percent susceptibility was 38% for the Etest® method and 50% and 54% for the 2 broth microdilution methods. All differences in susceptibility were within one 2-fold dilution.

Pharmacokinetics of Telavancin at Fixed Doses in Normal-Body-Weight and Obese (Classes I, II, and III) Adult Subjects

A recommended total-body-weight (TBW) dosing strategy for telavancin may not be optimal in obese patients. The primary objective of this study was to characterize and compare the pharmacokinetics (PK) of telavancin across four body size groups: normal to overweight and obese classes I, II, and III. Healthy adult subjects (n = 32) received a single, weight-stratified, fixed dose of 500 mg (n = 4), 750 mg (n = 8), or 1,000 mg (n = 20) of telavancin. Noncompartmental PK analyses revealed that subjects with a body mass index (BMI) of ≥40 kg/m² had a higher volume of distribution (16.24 ± 2.7 liters) than subjects with a BMI of <30 kg/m² (11.71 ± 2.6 liters). The observed area under the concentration-time curve from time zero to infinity (AUC_0-∞) ranged from 338.1 to 867.3 mg · h/liter, with the lowest exposures being in subjects who received 500 mg. AUC_0-∞ values were similar among obese subjects who received 1,000 mg. A two-compartment population PK model best described the plasma concentration-time profile of telavancin when adjusted body weight (ABW) was included as a predictive covariate. Fixed doses of 750 mg and 1,000 mg had similar target attainment probabilities for efficacy as doses of 10 mg/kg of body weight based on ABW and TBW, respectively. However, the probability of achieving a target area under the concentration-time curve from time zero to 24 h of ≥763 mg · h/liter in association with acute kidney injury was highest (19.7%) with TBW-simulated dosing and lowest (0.4%) at the 750-mg dose. These results suggest that a fixed dose of 750 mg is a safe and effective alternative to telavancin doses based on TBW or ABW for the treatment of obese patients with normal renal function and Staphylococcus aureus infections. (This study has been registered at ClinicalTrials.gov under identifier NCT02753855.).