The isolation of Bacillus anthracis specific lytic bacteriophages from the burial sites of animals which have died of anthrax and host susceptibility

The aim of the this study was to isolate Bacillus anthracis-specific lytic bacteriophages from soil samples collected from the burial sites of animals that died from anthrax and stored by our department within the scope of previous studies and routine analyses and to determine the host susceptibility of the isolated phages. Eleven soil samples culture negative for B. anthracis were used for this. The logarithmic culture of B. anthracis Sterne 34F2 strain was used as host bacteria and the Gamma phage was used as reference phage. The host specificity of the phages obtained was determined using an in-house bacterial collection consisting of 112 virulent B. anthracis isolates (104 animal and 8 soil field isolates) and 5 reference strains of Bacillus group (B. anthracis Sterne 34F2, B. megaterium Pasteur Inst. 5117, B. subtilis ATCC 6633, B. cereus ATCC 11778, B. thuringiensis RSCC 380). As a result, 18 field phages were isolated specific to B. anthracis. Gamma phage and all the field phages showed complete lytic activity on B. anthracis Sterne 34F2 strain and 112 field B. anthracis strains; 16 of the field phages did not show any lytic activity on the Bacillus group strains other than the Sterne 34F2, while two phages coded SS and PB caused partial lysis on B. megaterium Pasteur Inst. 5117. This study is important as it involves the isolation of lytic phages with a narrow host specificity. Considering that lytic phages are more advantageous as therapeutic agents due to their self-replication and self-limiting properties that reveal automatic dosing patterns while lysing the host bacteria, the phages obtained from the current study may have the potential to be used as alternative diagnostic tools, therapeutic agents or environmentally friendly decontaminants in this regard.