Genomic relatedness of colonizing and invasive disease Klebsiella pneumoniae isolates in South African infants.

Klebsiella pneumoniae (KPn) colonizes multiple anatomical sites and is a leading cause of invasive disease and death in African children; however, there is no comparative genomic analysis between colonizing and invasive strains. This study investigated the genomic relatedness of KPn colonizing and invasive isolates in South African infants; and evaluated the relative invasiveness of KPn isolates based on sequence types (ST), capsular (KL), and lipopolysaccharide (O) loci by calculating case-carrier ratios (CCRs). There was less genomic diversity amongst invasive (22 ST, 17 K-loci) than colonizing isolates (31 ST, 29 K-loci), with invasive isolates being 8.59-fold and 3.49-fold more likely to harbour genes encoding for multi-drug resistance and yersiniabactin production compared with colonizing isolates. The CCRs for KL102 and O1/O2v2 were > 1, and < 1 for KL8, ST1414, and O1O2v1. Identifying high-risk strains, including KL102 and O1O2v2, that may have a higher potential to cause invasive disease, could enhance risk assessment and management strategies in vulnerable populations.