A powerful mechanism for protection against disease in animals is synergy between metabolites present in the natural microbiota of the host and antimicrobial peptides (AMPs) produced by the host. We studied this method of protection in amphibians in regard to the lethal disease chytridiomycosis, which is caused by Batrachochytrium dendrobatidis (Bd). In this study, we show that the AMPs of Rana muscosa, as well as the metabolite 2,4-diacetylphloroglucinol (2,4-DAPG) from Pseudomonas fluorescens, a bacterial species normally found on the skin of R. muscosa, were inhibitory to the growth of Bd in vitro. When both AMPs and 2,4-DAPG were used in growth inhibition assays, they worked synergistically to inhibit the growth of Bd. This synergy resulted in reduced minimum concentrations necessary for inhibition by either 2,4-DAPG or AMPs. This inhibitory concentration of AMPs did not inhibit the growth of a P. fluorescens strain that produced 2,4-DAPG in vitro, although its growth was inhibited at higher peptide concentrations. These data suggest that the AMPs secreted onto frog skin and the metabolites secreted by the resident beneficial bacteria may work synergistically to enhance protection against Bd infection on amphibian skin. These results may aid conservation efforts to augment amphibian skins' resistance to chytridiomycosis by introducing anti-Bd bacterial species that work synergistically with amphibian AMPs.

Background: Linezolid standard dosing is fixed at 600 mg q12h for adults. Literature suggests critically-ill, obese patients require higher doses. The study aim is two-fold: (i) to describe linezolid PK and (ii) to evaluate if PK/PD target attainment is achieved with standard dosing in critically-ill, obese patients with severe SSTIs. Methods: Adult patients with a body mass index (BMI) ≥ 30 kg/m2 and receiving IV linezolid from August 2018 to April 2019 were eligible for consent in this prospective study. Severe SSTIs were defined as necrotizing fasciitis, myonecrosis, or SSTI with sepsis syndrome. Four blood samples were collected at steady state at 1, 3, 5 hours post-infusion and as a trough. Target attainment was defined as achieving AUC0-24h/MIC ≥ 100 hr*mg/L. Monte Carlo simulations were used to determine probability of target attainment (PTA). Results: Eleven patients were included in the study. The median BMI was 45.7 kg/m2 and median total body weight (TBW) was 136.0 kg. Seven patients received standard linezolid doses and four received 600 mg q8h. A one-compartment model described linezolid PK. Based on AUC0-24h/MIC targets, for non-cirrhotic patients at 140 kg, PTA with standard linezolid doses was 100%, 98.8%, 34.1%, and 0% for MICs 0.5, 1, 2, and 4 mg/L, respectively. Conclusion: Target attainment ≥ 90% is not achieved with standard linezolid doses for non-cirrhotic patients ≥ 140 kg with MICs ≥ 2 mg/L. This study adds to accumulating evidence that standard linezolid doses may not be adequate for all patients.

Asparaginase is a chemotherapeutic agent that is commonly used in combination with other medications for the treatment of acute lymphoblastic leukemia. An adverse effect of asparaginase includes hepatotoxicity, which can lead to severe liver failure and death. Several reports have documented successful treatment of asparaginase-induced hepatotoxicity using levocarnitine (l-carnitine) and vitamin B complex. Herein, we report a patient with acute lymphoblastic leukemia that experienced acute liver injury following pegaspargase administration. Our patient was successfully treated with l-carnitine and vitamin B complex for 8 days and achieved recovery of hepatic function. Furthermore, we review the current literature and provide a recommendation on a regimen that can be used as an option for the treatment of asparaginase-induced hepatic injury.

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