Prevention of antibiotic resistance created by experimental evolutionary microbiology in Staphylococcus aureus and Escherichia coli with herbal substances

Abstract

Background and Aims: Recently, one of the biggest problems of the world is a bacterial antimicrobial resistance, that is developing against most of the existing antibiotics. In addition to conducting studies that continue to discover new antimicrobial agents for combating multidrug resistant bacteria, steps should be taken for the protection of existing antibiotics. With this in mind, many modern and classical strategies have been developed, and among them, using essential oils or extracts obtained from plants, which may be a practical and effective alternative. Methods: We used the experimental evolutionary microbiology method to determine the effects of herbal substances, such as cinnamaldehyde from cinnamon, epigallocatechin gallate from greentea, curcumin from turmeric, punicalagin from pomegranate, and clove oil from clove, on the prevention or delay of antimicrobial resistance. In this study, Staphylococcus aureus and Escherichia coli standard and clinical strains were gradually exposed to increasing sub-inhibitory concentrations of meropenem and ciprofloxacin with or without the presence of herbal substances. Results: Resistance was developed in the E. coli and S. aureus control groups which were exposed only to ciprofloxacin, but, when herbal substances were included to the test, there was no resistance development. When the control groups were exposed only to meropenem, there was only an increase in the minimum inhibitory concentrations (MIC), but they did not become resistant, and we observed similar MIC values when we added the herbal substances to the test. Conclusion: These results showed that herbal substances might contribute to lowering MIC values of antibiotics and may help prevent the development of resistance in the studied bacteria.