Epidemiology, resistance and virulence of neonatal <i>Klebsiella pneumoniae</i> isolates from a tertiary hospital in Tanzania

Abstract

BACKGROUND: Klebsiella pneumoniae (Kp) is a cause of blood stream infections (BSI) in neonates and poses a major clinical challenge. Hence, we aimed to investigate molecular epidemiology, transmission dynamics and underlying virulence and resistance patterns of invasive/colonised Kp isolates from neonates admitted at Bugando-Medical-Centre in Mwanza, Tanzania. METHODS: This retrospective molecular-epidemiology cohort-study was conducted between January 2023 and June 2024. Automated resistance testing and Illumina whole-genome sequencing were performed. MLST, LPS (O)- and capsule (K)-typing, phylogenetic analysis, and annotation of resistance/virulence genes (using Kleborate) were conducted. RESULTS: Neonates (f/m: 13/11) had an average birth weight of 2545.8 g. Retrieved isolates (n=41) revealed high resistance-rates for penicillins (ampicillin 95.1%; 39/41, piperacillin 92.7% (38/41)), cephalosporins (87.8% (36/41) to 90.2%, (37/41)) and aminoglycosides (73.2%, 30/41). Penicillin-beta-lactamase-inhibitor combinations increased susceptibility (ampicillin-sulbactam (87.8%, 36/41); piperacillin-tazobactam 41.5% (17/41)). Ciprofloxacin resistance was seen in 58.5% (24/41), while carbapenems retained high activity (95.1%, 39/41). WGS identified 16 MLST sequence types, with ST2390 (7/41), ST48 (6/41) and ST101 (5/41) predominating. K and O typing identified KL107 (48.8%, 20/41), KL113 (17.1%, 7/41) and O1αβ,2α (56.1%, 23/41) being most prevalent. There was no sign of geno-/phenotypic hypervirulence. Kleborate resistance score confirmed 34 phenotypically positive ESBL isolates and one MDR isolate. Phylogenetic analysis grouped isolates into seven clusters, with evidence of intra-hospital transmission in five and potential gut-to-bloodstream translocation in two. CONCLUSION: Neonatal Kp isolates show high ESBL prevalence, limited virulence, and signs of hospital transmission, underscoring the urgent need for enhanced infection control and antimicrobial stewardship in African neonatal units.