Antimicrobial activity of harzianic acid against Staphylococcus pseudintermedius

Abstract

The emerging concern about the increase of antibiotic resistance has encouraged research efforts to develop effective alternatives to counteract bacterial infections. Herein, we studied a new perspective to therapeutic treatment against Staphylococcus pseudintermedius, an opportunistic pathogen documented as the major cause of skin, ear, and post-operative bacterial infections in dogs and cats. Antimicrobial activity of secondary metabolites produced by selected microbial strains belonging to Trichoderma, Talaromyces, Clonostachys and Coniothyrium fungal genera has been tested against S. pseudintermedius. Several extracts, particularly those obtained from Trichoderma harzianum E45 and ET45, showed a significant antimicrobial activity towards S. pseudintermedius methicillin-resistant (MRSP) and methicillin-susceptible (MSSP) strains. Bioassay-guided fractionation of E45 and ET45 extracts allowed to isolate harzianic acid as the major compound responsible for biological activities (e.g. antimicrobial, antibiofilm formation and biofilm disaggregation).

Graphical Abstract

Keywords:

• Trichoderma
• Talaromyces
• Clonostachys
• Coniothyrium
• harzianic acid
• secondary metabolites
• Staphylococcus pseudintermedius
• antibiotic resistance

Acknowledgements

The authors would like to thank Salvatore Monnolo for technical support in laboratory of bacteriology and Dr Roberta Marra for manuscript revisions.

Disclosure statement

The authors declare no conflicts of interest.

Additional information

Funding

MIURPON [grant number Linfa 03PE_00026_1; grant number Marea 03PE_00106]; MIUR-GPS [grant number Sicura DM29156]; POR FESR CAMPANIA 2014/2020- O.S. 1.1 [grant number Bioagro CUP B63D18000270007]; MISE [grant number Protection F/050421/01-03/X32]; PRIN 2017 [grant number PROSPECT 2017JLN833]; Regione Veneto PSR 2014–2020 [grant number DIVINE 3589659].