Isolation and characterization of φkm18p, a novel lytic phage with therapeutic potential against extensively drug resistant Acinetobacter baumannii.
OBJECTIVE
To isolate phages against extensively drug resistant Acinetobacter baumannii (XDRAB) and characterize the highest lytic capability phage as a model to evaluate the potential on phage therapy.


RESULTS
Eight phages were isolated from hospital sewage and showed narrow host spectrum. Phage φkm18p was able to effectively lyse the most XDRAB. It has a dsDNA genome of 45 kb in size and hexagonal head of about 59 nm in diameter and no tail. Bacterial population decreased quickly from 10(8) CFU ml(-1) to 10(3) CFU ml(-1) in 30 min by φkm18p. The 185 kDa lysis protein encoded by φkm18p genome was detected when the extracted protein did not boil before SDS-PAGE; it showed that the lysis protein is a complex rather than a monomer. Phage φkm18p improved human lung epithelial cells survival rates when they were incubated with A. baumannii. Combination of phages (φkm18p, φTZ1 and φ314) as a cocktail could lyse all genotype-varying XDRAB isolates.


CONCLUSIONS
Infections with XDRAB are extremely difficult to treat and development of a phage cocktails therapy could be a therapeutic alternative in the future. Phage φkm18p is a good candidate for inclusion in phage cocktails.
Division of Respiratory and Critical Care Medicine, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung, Taiwan, ROC.
Gwan-Han
GH
Shen
Jiun-Ling
JL
Wang
Fu-Shyan
FS
Wen
Kai-Ming
KM
Chang
Chih-Feng
CF
Kuo
Chun-Hung
CH
Lin
Huei-Ru
HR
Luo
Chih-Hsin
CH
Hung
D000151:Acinetobacter Infections / Q000382:microbiology / Q000628:therapy; D040981:Acinetobacter baumannii / Q000187:drug effects / Q000502:physiology / Q000821:virology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001433:Bacteriolysis; D001435:Bacteriophages / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D001691:Biological Therapy; D002460:Cell Line; D002470:Cell Survival; D004279:DNA, Viral / Q000235:genetics; D024881:Drug Resistance, Bacterial; D010450:Endopeptidases / Q000378:metabolism; D016679:Genome, Viral; D006801:Humans; D015183:Restriction Mapping; D012722:Sewage / Q000821:virology; D014764:Viral Proteins / Q000378:metabolism; D056189:Viral Tropism
D000900:Anti-Bacterial Agents; D004279:DNA, Viral; D012722:Sewage; D014764:Viral Proteins; D010450:Endopeptidases; C001143:endolysin