# Insight into the Roles of Albumin—Alone and in Combination with Either Voriconazole or Antimicrobial Peptides Derived from Chromogranin A—In the Growth of Different Microbial Species

## TL;DR

This study explores how albumin, alone or combined with other substances, affects the growth of various microbes, including Candida species.

## Contribution

The study reveals that albumin can have antimicrobial properties and may enhance or hinder the effects of antifungal drugs and peptides depending on the microbe.

## Key findings

- ThHSA combined with VCZ enhanced antifungal effects on some Candida species but promoted growth in resistant strains.
- BSA significantly enhanced the antimicrobial activity of catestatin against certain microbes but not cateslytin.
- Albumin's antimicrobial effects vary unpredictably across different microbial species.

## Abstract

Background: Whether therapeutic albumin (ThHSA) can serve as a defense tool in Candida species (spp.) infections is still a matter of debate, although many physicians are in the habit of infusing ThHSA to restore the physiological concentration of endogenous human serum albumin (HSA). Given the need for innovative anti-Candida strategies, we assessed in vitro the role of ThHSA alone or in combination with voriconazole (VCZ) in combating Candida spp. growth and the role of bovine serum albumin (BSA)—used as a substitute for HSA—with two endogenous bovine antimicrobial peptides in combating C. albicans and other microbes. Results: The combination of ThHSA with VCZ enhanced the antifungal effect on C. albicans, sensitive C. tropicalis, sensitive C. glabrata, and C. lusitaniae. However, for resistant C. tropicalis, the combination of ThHSA with VCZ promoted yeast growth, and VCZ tended to suppress the antimicrobial effect of ThHSA on resistant C. glabrata. As to the possible transposition of ThHSA-type properties to BSA (as regards the growth inhibition of other pathogens), we tested combinations of BSA with two physiological chromogranin A-derived antimicrobial peptides (catestatin and cateslytin). BSA enhanced significantly the activity of catestatin (but not cateslytin) in combating C. albicans, A. fumigatus, and M. luteus, but was inactive against S. aureus and E. coli. Conclusions: Our experiments support the fact that albumins display intrinsic antimicrobial properties, with an unpredictable growth inhibitory effect on various microbes. ThHSA can thus be an adjunctive tool for more efficient care of some, though not all, infections. The interaction of BSA with catestatin and cateslytin is related to their structure, with BSA significantly enhancing the effect of catestatin but not that of cateslytin.