Correlation of rpsU gene sequence clusters and biochemical properties, GC—MS spectra and resistance profiles of clinical Burkholderia spp. isolates

This study assessed the variation of phenotypic features of clinical isolates of Burkholderia spp. from common rpsU gene sequence clusters. A total of 41 clinical Burkholderia spp. isolates from German mucoviscidosis patients was subjected to rpsU gene sequencing. Biochemical assessment included the API systems 20 NE and 50 CHE as well as the Micronaut NF system. Fatty acid patterns were assessed using gas chromatography—mass spectrometry (GC—MS). Broth microdilution was used to identify minimum inhibitory concentrations. Five rpsU gene sequence clusters comprised more than one clinical isolate. Altogether, assignments to three species and seven clusters comprising more than one Burkholderia species were performed. Inhomogeneity of biochemical reactions within the clusters ranged from 0/28 to 45/50 reactions. The standard deviation for fatty acid distributions ranged from 0% to 11.5%. Minimum inhibitory concentrations within the clusters showed a wide variation but only minor differences between the clusters. Broad variations within identified rpsU gene sequence clusters regarding biochemical reactions, fatty acid patterns, and resistance patterns of clinical Burkholderia spp. isolates make the application of rpsU gene sequence analysis as a stand-alone procedure for discriminations within the Burkholderia cepacia complex unreliable.