Chromobacterium haemolyticum Pneumonia Associated with Near-Drowning and River Water, Japan

Abstract

We report a severe case of Chromobacterium haemolyticum pneumonia associated with near-drowning and detail the investigation of the pathogen and river water. Our genomic and environmental investigation demonstrated that river water in a temperate region can be a source of C. haemolyticum causing human infections.

Keywords: Chromobacterium haemolyticum; Japan; bacteria; environment; pneumonia; respiratory infections; whole-genome sequencing.

Figure 1

Core genome single-nucleotide variations in a phylogenetic analysis of 19 strains of Chromobacterium haemolyticum in a case of pneumonia associated with near-drowning in river water, Japan. In total, 252,974 SNV sites were detected in core genome region among 19 strains. The phylogenetic analysis with SNV data was constructed by maximum likelihood method. Two clinical isolates (CH06-BL and CH06-SPT) and 3 environmental isolates (CH08-RW1, CH08-RW2, and CH08-RW3) of C. haemolyticum in this study were discordant (27,867–29,491 SNVs). Scale bar indicates nucleotide substitutions per site. SNV, single nucleotide variant.

Figure 2

Metagenomic analysis of river water sample collected from the site of near-drowning of a patient with Chromobacterium haemolyticum pneumonia, Japan. A) Relative abundance of superkingdom, class of bacteria, and genus of betaproteobacteria in river water sample. The relative abundance of bacteria is 25.65%; the 10 most observed class and genus are summarized in cumulative bar charts. B) Comparison of relative abundance of bacteria causing pneumonia associated with drowning in genus level in the river water sample. The relative abundance of Chromobacterium, a Betaproteobacteria, is 0.073%.