Antimicrobial resistance and virulence characteristics of Klebsiella pneumoniae isolates in Kenya
Authors: Muraya Angela W. , Kyany’a Cecilia , Kiyaga Shahiid , Smith Hunter J. , Kibet Caleb , Martin Melissa J. , Kimani Josephine , Musila Lillian 
Published: February 2022

Klebsiella pneumoniae is a globally significant opportunistic pathogen causing healthcare-associated and community-acquired infections. This study examined the epidemiology and the distribution of resistance and virulence genes in clinical K. pneumoniae strains in Kenya. Eighty-nine K. pneumoniae isolates were collected over six years from five counties in Kenya and were analyzed using whole genome sequencing and bioinformatics. These isolates were obtained from community-acquired (62/89) and healthcare-associated infections (21/89), and the hospital environment (6/89). Genetic analysis revealed the presence of blaNDM-1 and blaOXA-181 carbapenemase genes and the armA and rmtF genes known to confer pan-aminoglycoside resistance. The most abundant extended-spectrum beta-lactamase genes identified were blaCTX-M-15 (36/89), blaTEM (35/89), and blaOXA (18/89). In addition, one isolate had a mobile colistin resistance gene (mcr-8). Fluoroquinolone resistance-conferring mutations in gyrA and parC genes were also observed. The most notable virulence factors were those associated with hyper-virulence (rmpA/A2 and magA), yersiniabactin (ybt), salmochelin (iro), and aerobactin (iuc and iutA). Thirty-eight distinct sequence types were identified, including known global lineages ST14, ST15, ST147, and ST307, and a regional clone ST17 implicated in regional outbreaks. In addition, this study genetically characterized two potential hypervirulent isolates and two community-acquired ST147 high-risk clones that contained carbapenemase genes, yersiniabactin, and other multidrug resistance genes. These results demonstrate that the resistome and virulome of Kenyan clinical and hospital environmental K. pneumoniae isolates are diverse. The reservoir of high risk-clones capable of spreading resistance and virulence factors have the potential to cause unmanageable infection outbreaks with high morbidity and mortality.

AUTHOR SUMMARY

Klebsiella pneumoniae is one of the human-disease-causing bacteria that easily acquires and spreads antibiotic resistance genes and is thus a serious threat to human health. We studied both the antibiotic resistance genes and the genes it uses to cause disease (virulence). Forty-two percent of our isolates were multidrug resistant (MDR). They carried several resistance and virulence genes bound in mobile circular DNA molecules called plasmids which easily migrate and spread the genes between bacteria. We identified 38 distinct K. pneumoniae strains (STs) distributed within the study sites. Fifteen isolates were classified under the groups of K. pneumoniae strains known to cause global infection outbreaks such as ST14, ST15 and ST147 collected from Nairobi and Kisumu, hotspot areas for spread of resistance. In particular, two ST147 isolates were resistant to carbapenems and one isolate to colistin, which are last line antibiotics. We also identified two isolates with the potential to cause high levels of disease. We concluded that the presence of highly resistant and virulent strains in the hospital and community demonstrates a need for the continuous monitoring and management of MDR K. pneumoniae infections to prevent disease outbreaks that are difficult to control and that lead to high death rate.