Isolation and characterization of BpL1, a broad acting lytic bacteriophage against Brucella

Abstract

AbstractWe have isolated a new broad acting lytic brucellaphage (BpL1) from the sewage of a dairy farm. The phage lysed all the 12Brucella abortusfield isolates,B. abortusstrain 99 andBrucella melitensisbut did not lyse any of the heterologous species tested viz.Staphylococcus aureus, Pasteurella multocida, Escherichia coli,andSalmonella species. Streaking the plaques onBrucellalawn gave clear zones along the streak lines. The plaques were circular with a diameter of 0.5- 3.0 mm. At a concentration of 10−4the phage count was 4.5 × 106plaques per ml. It was a tailed phage with icosahedral head (62.2 nm in diameter and 73.71 nm in length), and the head to tail length was 229.21 nm. The phage belonged to the order Caudovirales and familySiphoviridae. It was inactivated within one hour at 55°C and within 4 hours at −20°C. Treatment at pH 2 for 4 hours and at pH 4 for 12 hours inactivated it. It was inactivated after 4 hours exposure to sunlight, and within 4 minutes by UV light. Chloroform and Sodium Dodecyl Sulfate inactivated it within 15 minutes. Lysozyme inactivated it within 1 hour whereas RNase treatment did not affect its activity.