Abstract

BACTERIOPHAGE KINETICS: A DOSE DEPENDENT STUDY OF METHICILLIN RESISTANT STAPHYLOCOCCUS AUREUS PHAGE

Vinod Kumar C.S.*, Suneeta Kalasuramath, Srinivasa H., Basavarajappa K.G.

ABSTRACT

Introduction: The practice of phage therapy, the application of phages to treat bacterial infections, has been around for approximately a century. Emergence of multidrug-resistant, extensively drug-resistant and pan drug-resistant bacteria and the limited prospects of producing new antibiotics have opened up the second window for the bacteriophages. Aims: to predict active effective therapy and passive effective therapy of Staphylococcus aureus phages against methicillin resistant Staphylococcus aureus by using cell growth assays. Material & Methods: Two different doses of MRSA (102 CFU/ml and 108 CFU/ml) were challenged with Staphylococcus aureus phages (102 PFU/ml and 109PFU/ml) and the bacteriophage kinetics were monitored in-vitro by using cell growth assay for 99 hours. Comparison of bacteriophage kinetics was determined by plotting area under the graph for every 3 hours till 18th hour. Results: When 108 CFU/ml of methicillin resistant Staphylococcus aureus were challenged with 109PFU /ml of Staphylococcus aureus phage, the bacteria growth was reduced when compared to normal growth of Staphylococcus aureus (Bacterial control). Six fold reductions in mean area were observed. Similarly the reduction of growth was more pronounced when 102 CFU of methicillin resistant Staphylococcus aureus was challenged with 109PFU/ml of Staphylococcus aureus phage. Mean area was almost same compared to the phage control at 12th hour indicating the clearance of the bacteria. But when lower concentration of phages (102 PFU/ ml) was used against higher concentration of bacteria, the rate of reduction was not as efficient when compared to higher concentration of phages (109 PFU ml). Conclusion: In dose dependent study higher concentration of phages were highly effective when compared to lower concentration of phages in relation to the initial density of bacteria. For active effective therapy higher concentration of phages are required and even lower concentration of phages could give rise to passive effective therapy.

Keywords: Bacteriophage kinetics, dose dependent study, methicillin resistant staphylococcus aureus phage, active and passive therapy.