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. 2025 Aug 12;12:1562641. doi: 10.3389/fvets.2025.1562641

Table 7.

Summary of studies on the antimicrobial efficacy of THY and THEO against various pathogens.

Pathogen(s) THY source Method MIC MBC/MFC Observations References Year
Aeromonas salmonicida subsp. masoucida,
A. salmonicida subsp. salmonicida,
A. hydrophila,
Edwardsiella tarda,
Vibrio vulnificus,
V. parahaemolyticus,
V. anguillarum
Pure THY Disk diffusion 0.01–0.32 mg/mL Not reported Inhibits growth, including strains resistant to amoxicillin and lincomycin (77) 2012
Streptococcus mutans,
St. salivarius,
St. sanguinis,
St. pyogenes,
Enterecoccus feacalis,
Pseudomonas aeruginosa,
Lactobacillus acidophilus,
Staphylococcus aureus
THEO from three different Thymus species (38.5%, 49.10% and 56.02% THY) Broth microdilution 2.5–160 g/mL 5–320 μg/mL THEO from T. serpyllum shows the strongest activity (32) 2013
St. pyogenes THEO (43.6% THY) Not specified Not reported Not reported Significant antibacterial activity against S. pyogenes (78)
E. coli O157 Pure THY Cell culture Not reported Not reported Reduces invasion and expression of colonization genes in E. coli O157 (27) 2014
Pseudomonas spp. THEO (77.5% THY) Not specified 0.4 mg/mL Not reported High sensitivity in all evaluated strains (79)
E. coli,
S. aureus,
P. aeruginosa,
K. pneumoniae
THY-enriched hydrogel Disk diffusion Not reported Not reported Significant activity against Gram-positive and Gram-negative bacteria (46) 2018
Escherichia coli,
Salmonella typhimurium,
S. aureus
THEO (35.4% THY) Well diffusion Not reported Not reported Particularly effective against Gram-positive bacteria at all tested doses (80) 2019
E. coli Pure THY Incremental subculture Not reported Not reported Development of tolerance in E. coli with morphological and genetic changes observed (81)
S. pseudintermedius,
P. aeruginosa,
M. pachydermatis
THEO and OEO (THY and CAR) Broth microdilution 0.02–0.25% (200–2,292 μg/mL) 2 dilutions higher Superior antimicrobial activity of THY and CAR over THEO and OEO (82)
S. aureus THY and derivatives Broth microdilution Not reported Not reported THY derivatives are effective (51) 2020
E. coli,
S. entérica,
S. aureus
Oregano EO (OEO) Broth microdilution Not reported Not reported Inhibits E. coli and S. aureus growth, reduces microbial load in insect vectors (83)
E. coli Pure THY Incremental subculture Not reported Not reported No resistance was induced in E. coli compared to amoxicillin (84)
E. coli,
S. enterica
THY (hydrolytic derivative TBG) Not specified Not reported Not reported No significant effect of THY on antibiotic susceptibility (85) 2021
Enterococcus faecalis,
St. canis,
Proteus mirabilis,
S. pseudintermedius,
P. aeruginosa
THY, OEO Not specified 18.8–9,600 ppm 37.5–9,600 ppm All compounds show antimicrobial activity against isolates (86)
S. aureus,
E. coli,
St. uberis
Pharmaceutical formulation (25% THY) Broth microdilution 22.72–45.4 mg/mL 45.4–90.09 mg/mL Strong antimicrobial activity against common mastitis pathogens (66) 2022
E. coli,
T. pyogenes
THEO, OEO and CIN Not specified >32,768 mg/mL >32,768 mg/mL Synergistic effects were observed with combined EOs against T. pyogenes and most E. coli strains (5) 2023
Prototheca bovis THY Broth microdilution 0.06 to 0.25% THY appears effective against Prototheca species, and may be useful for environmental disinfection in barn (87) 2024