Summary
Klebsiella pneumoniae an opportunistic pathogen, is a major cause of respiratory tract, bloodstream and other infections worldwide. Bacterial infections have a great impact on public health and contribute significantly to morbidity and mortality across all age-span.
One of the promising candidates for vaccine development is the surface polysaccharides, particularly LPS O-antigens. Studies on the distribution and diversity of Klebsiella pneumoniae have mainly been focused in the developed countries and genomes from sub-Saharan Africa, are not well represented in the genome datasets. Hence, the need to investigate the diversity of O-antigen and K-antigen for a vaccine to be effective in these settings.
In this project we will screen a collection of 250 invasive and carriage klebsiella pneumoniae strains archived at International Foundation Against Infectious Disease in Nigeria using whole genome sequencing. This will enable us to identify the prevailing serotypes. Findings from this project will provide invaluable data to further inform Klebsiella pneumoniae vaccine development in Africa.
Project Outcomes:
Klebsiella pneumoniae infections are major contributors to the global burden of disease, most of these fatal infections occur in low- and middle-income countries (LMICs), where drug resistant bacteria are more prevalent and appropriate microbiologic diagnostic services are lacking. One of the effective public health interventions to tackle the problem of drug resistant Klebsiella is vaccine development to prevent infection. We present preliminary results from our study which involves whole genome sequencing of invasive and colonising Klebsiella pneumoniae strains.
The isolates were sequenced using Illumina NextSeq. Reads were assembled and annotated, and various genetic elements, including antibiotic resistance genes, sequence types, and serotypes, were identified using bioinformatics tools. Several antimicrobial resistance genes were identified (β-lactamase genes, blaCTX-M-15, blaTEM-1b, blaOXA-1, blaSHV-12 and blaOKP-B-2-like concomitantly with other resistance genes acc (6′)-lb-cr, aadAI6, qnr-like, and fosA-like that confer resistance to aminoglycosides, fluoroquinolones, and fosfomycin respectively.
Multi-locus sequence typing (MLST) identified 59 different sequence types (STs) some of which represented new STs (7). Analysis of genetic loci responsible for encoding O-polysaccharide antigens and capsule in K. pneumoniae, which represent possible vaccine candidates, revealed that O1 and O3 were the predominant variants, constituting around 67% of all genomes, while capsule types exhibited greater heterogeneity.
Furthermore, most of the serotypes detected in our study are included in the Kleb4V tetravalent bioconjugate vaccine.