Isolation and Characterization of Lytic Bacteriophages infecting Staphylococcus epidermidis

Abstract

The Staphylococcus epidermidis isolates were obtained during a period extended between September 2014 and January 2015, depending on biochemical tests and VITEK 2 system. Several sewage water samples were assayed using a plaque assay of double agar overlay as a source of S. Epidermidis phages. The bacteriophages were described depending on plaques size and shapes. Phage 1 was the most predominant in the bacterial lawn and able to infect other S. species such as S. aureus. Therefore, it was decided to study the effect of temperature on its original titer. The results revealed a gradual decrease in the phage titer with increasing dilution number. Each temperature at several incubation periods, significantly vary depending on phage titer. The optimum temperature was 40 ° C, while the 80 ° C was represented the inhibitor temperature. L.S.D. at level (0.05) for interaction was 39.552. The pH 6.5 – 7.5 were represented the optimal pH for the best phage activity while the phage titer beginning to decline in above and below this range of optimal pH , L.S.D. at level 0.05 was 17.898. In conclusion, our study found that Phage1 was considered as predominant phage because of their ability to infect other Staphylococci species such as S. Aureus.