Case report of Curtobacterium isolated from a catheter tip sample misidentified as Cronobacter

The Curtobacterium genus is a member of the family Microbacteriaceae, and Curtobacterium species are recognized as plant pathogens. The aim of this study was to investigate a dubious result of species identification for an infection located on a catheter tip of a patient with Covid-19. A strain isolated from a catheter tip sample, identified by VITEK (R) 2 as Cronobacter spp., was submitted to polyphasic analysis: Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) using VITEK (R) MS, real-time polymerase chain reaction targeting dnaG gene, and 16S rRNA full gene Sanger sequencing analysis for confirmation. The strain presented negative result using qPCR and could not identified by MALDI-TOF MS. 16S rRNA full gene Sanger sequencing analysis identified the strain as Curtobacterium spp. The Gram-variable characteristic (Gram-negative instead of Gram-positive) of the isolated strain was the responsible for the misidentification by VITEK (R) 2 and VITEK (R) MS did not identify the strain. 16S rRNA full gene sequencing analysis identified the strain as Curtobacterium genus, but other complementary techniques are necessary to identify at species level.

Automated summary

This study investigated an uncertain species identification for an infection located on a catheter tip of a patient with Covid-19. The strain, initially identified as Cronobacter spp. by VITEK (R) 2, was later confirmed to be Curtobacterium spp. through polyphasic analysis. The misidentification occurred due to the Gram-variable characteristic of the strain. Additional techniques are required for species-level identification.