DETERMINATION OF ANTIBACTERIAL AND ANTIBIOFILM ACTIVITY OF TERPINEN 4-OL AGAINST SOME STANDARD BACTERIAL STRAINS

Öz

Objective: Antimicrobial resistance in bacteria is becoming increasingly common and poses a serious challenge, particularly in treatment of infections where biofilm formation is involved. Biofilms enable bacteria to survive under harsh conditions and increase their resistance to antibiotics, thereby reducing the success of standard treatments. Terpinen-4-ol, the main compound of Melaleuca alternifolia (tea tree) essential oil, has shown notable antimicrobial effects. This study focuses on evaluating the antimicrobial effectiveness of terpinen-4-ol against selected standard bacterial strains and also determinating the antibiofilm activity at subMIC concentrations. Material and Method: In this study, Enterococcus faecalis WHO3 (vanA), Pseudomonas aeruginosa PAO1, Staphylococcus aureus ATCC 43300 (MRSA), Staphylococcus epidermidis ATCC 35984, and Streptococcus mutans ATCC 12575 were used to be tested. Minimum inhibitory concentrations (MICs) were determined by broth microdilution method according to EUCAST standards. Biofilm formation and inhibition assays were tested by the modified crystal violet method. The antibiofilm activity of terpinen-4-ol was evaluated at a sub-inhibitory concentration corresponding to MIC/2, and the extent of inhibition was quantified as the percentage reduction relative to untreated control biofilm formation. Result and Discussion: The MIC values of terpinen-4-ol against the tested bacteria ranged from 0.0625% to 0.5% (v/v). Even at subMIC levels, terpinen-4-ol significantly reduced biofilm formation. Inhibition rates were 79.95% for P. aeruginosa PAO1, 77.79% for S. epidermidis ATCC 35984, and 73.23% for S. mutans ATCC 12575. These results suggest that terpinen-4-ol is effective not only in inhibiting bacterial growth but also in reducing biofilm formation, highlighting its potential as a promising candidate for alternative or complementary treatment strategies, especially against biofilm-associated and resistant infections.

Anahtar Kelimeler

• Antibacterial activity
• antibiofilm activity
• terpinen-4-ol

TERPINEN 4-OL’ÜN ÇEŞİTLİ STANDART BAKTERİ SUŞLARINA KARŞI ANTİBAKTERİYEL VE ANTİBİYOFİLM AKTİVİTESİNİN BELİRLENMESİ

Öz

Amaç: Bakteriler tarafından antimikrobiyal direnç giderek daha yaygın hale gelmekte ve özellikle biyofilm oluşumunun etkili olduğu enfeksiyonlarda ciddi bir sorun oluşturmaktadır. Biyofilmler, bakterilerin zorlu koşullarda hayatta kalmasına yardımcı olarak antibiyotiklere karşı direnç geliştirmelerine neden olur ve standart tedavilerin etkinliğini azaltır. Melaleuca alternifolia (çay ağacı) uçucu yağının ana etken maddelerinden biri olan terpinen-4-ol, belirgin antimikrobiyal etkiler göstermektedir. Bu çalışma, seçilen standart bakteri suşlarına karşı terpinen-4-ol’ün antimikrobiyal etkinliğini ve aynı zamanda subMİK konsantrasyonda antibiyofilm aktivitesini araştırmayı amaçlamaktadır. Gereç ve Yöntem: Bu çalışmada, Enterococcus faecalis WHO3 (vanA), Pseudomonas aeruginosa PAO1, Staphylococcus aureus ATCC 43300 (MRSA), Staphylococcus epidermidis ATCC 35984 ve Streptococcus mutans ATCC 12575 test bakterileri olarak kullanılmıştır. Minimum inhibitör konsantrasyon (MİK) değerleri, EUCAST standartlarına göre broth mikrodilüsyon yöntemi ile belirlenmiştir. Biyofilm oluşumu ve inhibisyonu modifiye kristal viyole yöntemi ile incelenmiştir. Terpinen 4 ol’ün antibiyofilm aktivitesi MIK/2 konsantrasyonda belirlenip, ana biyofilm oluşumuna göre farkı yüzde azalma olarak belirtilmiştir. Sonuç ve Tartışma: Terpinen-4-ol’ün test edilen bakterilere karşı MİK değerleri %0.0625 ile %0.5 (v/v) arasında değişmiştir. Sub MİK düzeylerinde bile biyofilm oluşumunu önemli ölçüde azaltmıştır. Biyofilm inhibisyon oranları; P. aeruginosa PAO1 için %79.95, S. epidermidis ATCC 35984 için %77.79 ve S. mutans ATCC 12575 için %73.23 olarak ölçülmüştür. Bu bulgular, terpinen-4-ol’ün yalnızca bakteri çoğalmasını değil, aynı zamanda biyofilm oluşumunu da azaltmada etkili olduğunu göstermekte ve biyofilmle ilişkili dirençli enfeksiyonlara karşı alternatif veya destekleyici tedavi stratejileri için umut vadeden bir aday olduğunu göstermektedir.

Anahtar Kelimeler

• Antibakteriyel aktivite
• antibiyofilm aktivite
• terpinen-4-ol

Kaynakça

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