Efficiency of Plating and Temperature-Dependent Storage Stability of Two Lytic Pseudomonas aeruginosa Bacteriophages

Öz

This study investigated the efficiency of plating (EOP) and storage stability of two lytic bacteriophages, vB_PaeS-K10 and vB_PaeS-K13, active against Pseudomonas aeruginosa. Previous host range analyses demonstrated that both phages exhibited lytic activity against 10 of 13 tested P. aeruginosa strains. EOP analyses performed on these susceptible strains revealed that both phages were capable of infecting 90% of the tested isolates. Phage vB_PaeS-K10 showed high infection efficiency against three strains, whereas phage vB_PaeS-K13 exhibited high efficiency against two strains. The observed variation in EOP values among strains indicated that phage susceptibility can differ considerably even within the same bacterial species and should therefore be evaluated at the strain level. The storage stability of vB_PaeS-K10 and vB_PaeS-K13 phages was evaluated for 180 days at −80°C, −20°C, 4°C, 25°C, and 37°C. Two-way ANOVA demonstrated that both storage temperature and storage duration significantly affected phage viability (p < 0.001). Overall, both phages maintained high stability at low temperatures, although their responses to storage conditions differed. Phage vB_PaeS-K10 exhibited greater stability at −80°C, 4°C, and 37°C, whereas phage vB_PaeS-K13 showed superior stability at −80°C, −20°C, 4°C, and 25°C. Multiple linear regression analysis identified storage duration as the primary factor influencing phage titer reduction in both phages. Furthermore, a significant interaction between storage temperature and duration was observed only for phage vB_PaeS-K10 (p < 0.05), suggesting a more complex response to storage conditions compared with phage vB_PaeS-K13. In conclusion, vB_PaeS-K10 and vB_PaeS-K13 phages possess broad host ranges against P. aeruginosa and exhibit distinct storage stability profiles depending on temperature. These findings contribute to the selection of suitable phages and optimization of storage conditions for future phage-based biocontrol and phage therapy applications targeting P. aeruginosa.

Anahtar Kelimeler

• Bacteriophage
• biocontrol
• storage stability
• efficiency of plating (EOP)
• Pseudomonas aeruginosa

İki Litik Pseudomonas aeruginosa Bakteriyofajının Plak Oluşturma Etkinliği ve Sıcaklığa Bağlı Depolama Stabilitelerinin Değerlendirilmesi

Öz

Öz Bu çalışmada, Pseudomonas aeruginosa'ya karşı litik aktivite gösteren vB_PaeS-K10 ve vB_PaeS-K13 bakteriyofajlarının plak oluşturma etkinlikleri (EOP) ile farklı depolama sıcaklıklarındaki stabiliteleri araştırılmıştır. Daha önce gerçekleştirilen konak aralığı analizlerinde her iki fajın da test edilen 13 P. aeruginosa suşundan 10'una karşı litik aktivite gösterdiği belirlenmiştir. Bu suşlar üzerinde gerçekleştirilen EOP analizleri, her iki fajın da test edilen suşların %90'ını enfekte edebildiğini ortaya koymuştur. vB_PaeS-K10 fajı üç suşta yüksek enfeksiyon etkinliği gösterirken, vB_PaeS-K13 fajı iki suşta yüksek etkinlik sergilemiştir. Sonuçlar, aynı bakteri türüne ait suşlar arasında faj duyarlılığının önemli farklılıklar gösterebildiğini ve konak-faj etkileşimlerinin suş düzeyinde değerlendirilmesi gerektiğini ortaya koymuştur. Fajların depolama stabiliteleri −80°C, −20°C, 4°C, 25°C ve 37°C sıcaklıklarda 180 gün boyunca incelenmiştir. İki yönlü varyans analizi sonuçları, depolama sıcaklığı ve süresinin faj canlılığı üzerinde istatistiksel olarak anlamlı etkiye sahip olduğunu göstermiştir (p<0,001). Her iki faj da düşük sıcaklıklarda yüksek stabilite göstermiştir. vB_PaeS-K10 fajı özellikle −80°C, 4°C ve 37°C koşullarında daha yüksek stabilite sergilerken, vB_PaeS-K13 fajı −80°C, −20°C, 4°C, ve 25°C’de daha iyi korunmuştur. Çoklu doğrusal regresyon analizleri, depolama süresinin her iki faj için de titre değişimini etkileyen temel faktör olduğunu ortaya koymuştur. Ayrıca sıcaklık ve depolama süresi etkileşimi yalnızca vB_PaeS-K10 fajında anlamlı bulunmuştur (p<0,05). Sonuç olarak, vB_PaeS-K10 ve vB_PaeS-K13 fajlarının geniş konak aralığına sahip olduğu ve depolama koşullarına bağlı olarak farklı stabilite profilleri sergilediği belirlenmiştir. Elde edilen bulgular, P. aeruginosa'ya karşı kullanılabilecek faj bazlı biyokontrol ve faj terapi uygulamalarında uygun faj seçimi ve depolama koşullarının belirlenmesine katkı sağlamaktadır.

Anahtar Kelimeler

• Bakteriyofaj
• biyokontrol
• depolama stabilitesi
• plak oluşturma etkinliği (EOP)
• Pseudomonas aeruginosa

Kaynakça

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