Selected antimicrobial essential oils to eradicate multi-drug resistant bacterial biofilms involved in human nosocomial infections

Abstract

Biofilms are the primary source of contamination linked to nosocomial infections by promoting bacterial resistance to antimicrobial agents, including disinfectants. Using essential oils, this study aims to inhibit and eradicate the biofilm of enterobacteria and staphylococci responsible for nosocomial infections at Guelma Hospital, northeastern Algeria. Thymbra capitata, Thymus pallescens and Artemesia herba-alba essential oils were evaluated against clinical strains of Klebsiella pneumoniae, Escherichia coli, and Staphylococcus aureus. The antimicrobial activity of the essential oils under consideration was assessed using an agar disc diffusion assay and the determination of minimum inhibitory concentrations (MICs). In addition, the crystal violet method and scanning electron microscopy (SEM) evaluated biofilm inhibition and eradication by those antimicrobial agents. The results indicate that T. pallescens essential oil was the most effective antimicrobial agent against pathogenic bacteria, with large zones of inhibition (up to 50 mm against S. aureus), low MICs (0.16 to 0.63 mg/mL), and powerful biofilm eradication up to 0.16 mg/mL in both 24 h and 60-min exposure times. Thus, Algerian thyme and oregano could be used in various ways to combat the biofilm that causes nosocomial infection in local hospitals.

Keywords:

• Biofilm eradication
• nosocomial infections
• essential oils
• multi-drug resistant bacteria

Acknowledgements

The authors would like to thank all the researchers affiliates at the Emerging Infectious and Tropical Diseases Research Unit (URMITE), Aix-Marseille University, France, who helped in the molecular characterization of the studied strains. The authors are also grateful to the CRAPC Biskra team for their assistance with the SEM analysis and Gabriela Kouahla for proofreading the manuscript.

Disclosure statement

All authors have read and approved the manuscript and declare that they have no conflict of interest.

Additional information

Funding

This work was supported by the General Direction of Research and Development DGRSDT Algeria under grant Number (D01N01UN130120180002).