Evaluation of in vitro growth-inhibitory potential of combinations of isopropylmethylphenol isomers against Staphylococcus aureus in liquid and vapour phase

Marcela Růžičková

Bakalářská práce

Abstract:

Staphylococcus aureus is a causative agent of lower respiratory tract infections and represents a major global health burden, particularly in low-income countries due to limited access to healthcare and high treatment costs. With the increasing emergence of antibiotic resistance, new therapeutic approaches are being investigated, including the antimicrobial activity of volatile compounds. In addition, combinations of such compounds show considerable potential for enhancing bacterial growth inhibition. In this study, combinations of two natural isopropylmethylphenol isomers, namely thymol and carvacrol, and one synthetic isomer, 4-isopropyl-3-methylphenol, were tested for their combinatory antimicrobial potential against S. aureus using broth volatilization chequerboard method. All tested combinations exhibited some degree of additive effect, with the best results obtained for combinations of 4-isopropyl-3-methylphenol with either thymol or carvacrol. The lowest ∑FIC, indicating a strong additive effect, was 0.58 and was tested for combination of 4-isopropyl-3-methylphenol with thymol in vapour phase. This combination showed two ∑FIC values below 0.6 and one below 0.7, further supporting a strong additive combinatory effect. For the combination of 4-isopropyl-3-methylphenol and carvacrol, one ∑FIC value below 0.6 and three below 0.7 were observed in vapour phase, along with two values below 0.7 in the liquid phase. These findings may support the development of future inhalation therapies. However, further in vivo studies are required to confirm safety and efficacy before practical application.

Keywords

broth volatilization chequerboard method, Staphylococcus aureus, combinatory effect, antimicrobial potential, volatile compounds

Jazyk práce: angličtina

Datum vytvoření / odevzdání či podání práce: 25. 4. 2026

Obhajoba závěrečné práce

• Obhajoba proběhla 27. 5. 2026
• Vedoucí: prof. Ing. Ladislav Kokoška, Ph.D.
• Oponent: Pavel Nový, Ph.D.

Česká zemědělská univerzita v Praze

Fakulta tropického zemědělství

Bakalářský studijní program:
Tropické zemědělství