BACTERIOPHAGES AS A TYPING TOOL FOR MELIOIDOSIS AGENT AND ITS AVIRULENT COUNTERPART, BURKHOLDERIA THAILANDENSIS

摘要

Melioidosis is a public health problem in Thailand. The most reliable diagnosis is the identification of the causative agent, Burkholderia pseudomallei. Attempts for strain identification include various molecular techniques and immunological assays. Since phage-typing method has been used for S. aureus and some enteric pathogens, this work was attempted to develop a phage-typing scheme for B. pseudomallei and its avirulent counterpart, B. thailandensis. Lysogenic strains were detected by cross-culturing method, and lytic phage induced from the phage producing strains. The resulting phages were characterized by electron micrographs, DNA profiles and the ability to lyse or lysogenize 100 isolates of the 2 species. Of the 11 phages isolated, 5 were recovered from B. thailandensis and 6 from B. pseudomallei. This phage-typing set typed 54 percent of 50 clinical and 72 percent of 29 soil isolates of B. pseudomallei, while 33 percent of 21 B. thailandensis were typed. The most reactive phage, the phage ΦE21, which was isolated from B. thailandensis, strongly and repeatedly lysed 36 of a hundred test isolates. Of the phages originated from B. pseudomallei, the phage ΦP2 from clinical specimen strongly and repeatedly lysed 6 percent of the test isolates. Induction of the phage ΦP2 into a serum-sensitive B. thailandensis strain E25 resulted in the resistance to 30 percent normal human serum of the phage-recipient E25TΦP2. Whether the change would correlate to its virulence requires further investigation.