ISOLATION OF LYTIC BACTERIOPHAGE AB72P AGAINST MULTI-DRUG RESISTANT ACINETOBACTER BAUMANNII ISOLATES OBTAINED FROM BURN INFECTION

Acinetobacter baumannii is a gram-negative pathogen that causes a wide range of hospital-acquired infections. Due to its intrinsic traits and its remarkable abilities to quickly acquire resistance genes, it has become resistant to most antimicrobial agents and a major problem for hospitals. In recent years, application of lytic bacteriophages has been considered to eradicate multi-drug resistant (MDR) A. baumannii from the clinical setting. The purpose of this research was to isolate a lytic bacteriophage against MDR A. baumannii isolate obtained from an infected burn site.

Different samples including lake, river and seawater, soil and municipal wastewater were tested for phage isolation by spot test and agar overlay method.

Lytic bacteriophage Ab72p against MDR A. baumannii isolate was isolated from municipal wastewater sample and classified as a member of Myoviridae family. The plaques formed by lytic phage Ab72p were completely clear plaque and had a diameter of 1-2 mm without halo. Phage Ab72p had an about 11 nm (in diameter) icosahedral head and a 17-22 nm (in length) contractile tail. The genome of phage Ab72p was double-stranded DNA with about 46 kb. Phage Ab72p was a very stable lytic phage in the high temperatures (up to 70 ºC) and wide range of pH (3 to 11), with an appropriate adsorption rate (99% adsorbed within 10 minutes), and large burst size (200 PFU per infected cell).

Phage Ab72p could be appropriate choice to prepare phage cocktail against A. baumannii isolates.