Sputum Gram stain of hypervirulent Klebsiella pneumoniae

Abstract

Hypervirulent Klebsiella pneumoniae has virulence genes relevant to capsule overproduction, which could lead to the finding of thick transparent area (“halo”) in Gram stain. In sputum Gram stain, observation of a large Gram-negative rod with a thick capsule may not only indicate that it is K. pneumoniae but also that it is a highly virulent strain.