Analysis of the Type VI secretion system and microbiological characteristics of hypervirulent Klebsiella pneumoniae causing urinary tract infections

Fei-Fei Li; Jing-Jing Li; Yin Zhang; Zhi-Yu Wu; Yuan-Hong Xu

doi:10.3855/jidc.21628

Analysis of the Type VI secretion system and microbiological characteristics of hypervirulent Klebsiella pneumoniae causing urinary tract infections

Authors

Fei-Fei Li Department of Laboratory, The First Affiliated Hospital of Anhui Medical University, HeFei 230022, AnHui, China
Jing-Jing Li Department of Laboratory, The First Affiliated Hospital of Anhui Medical University, HeFei 230022, AnHui, China
Yin Zhang Department of Laboratory, The First Affiliated Hospital of Anhui Medical University, HeFei 230022, AnHui, China
Zhi-Yu Wu Department of Laboratory, The First Affiliated Hospital of Anhui Medical University, HeFei 230022, AnHui, China
Yuan-Hong Xu Department of Laboratory, The First Affiliated Hospital of Anhui Medical University, HeFei 230022, AnHui, China

DOI:

https://doi.org/10.3855/jidc.21628

Keywords:

Hypervirulent Klebsiella pneumoniae, antimicrobial activity, bacterial competition, type vi secretion system, urinary tract infection

Abstract

Introduction: This study aimed to evaluate the Type VI secretion system (T6SS) and microbiological features in hypervirulent Klebsiella pneumoniae (hvKP) causing urinary tract infections (UTIs) in hospitalized adults.

Methodology: This retrospective, observational analysis encompassed 167 inpatients with UTIs caused by KP. The study investigated disease prevalence, antimicrobial susceptibility, gene carriage rates, and competition indices. Strains were classified as classic KP (cKP), T6SS-positive hvKP, or T6SS-negative hvKP, and compared for clinical traits, antimicrobial susceptibilities, and virulence gene carriage. Furthermore, the bacterial competition index of T6SS-positive hvKP strains was assessed through in vitro cultivation.

Results: Of 167 patients, 82 had hvKP and 85 had cKP. hvKP had higher rates of thrombosis, immunotherapy, hypoproteinemia, and longer hospital stays (p < 0.05). The 30-day mortality was 29.26% for hvKP vs. 12.94% for cKP (p = 0.045). hvKP showed highest resistance to cefuroxime (81.70%) and cKP to ampicillin/sulbactam (56.47%), with low resistance to tigecycline. The resistance to carbapenems (carbapenem-resistant KP, CR-KP) was significantly higher in hvKP compared to cKP (30.48% vs 16.47%, p = 0.032). Aerobactin and iroB differed between hvKP and cKP. T6SS-positive hvKP had higher rates of thrombosis and immunotherapy (p < 0.05). The 30-day mortality was 9.52% for T6SS-positive vs. 36.06% for T6SS-negative (p = 0.043). T6SS-positive hvKP strains exhibited lower resistance to carbapenems compared to T6SS-negative strains (9.52% vs 37.70%, p = 0.015). T6SS-positive strains had higher aerobactin and iroB positivity.

Conclusions: T6SS-positive hvKP exhibits lower antimicrobial resistance but stronger virulence, playing a major role in bacterial competition.

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Published

2026-01-31

How to Cite

Li F-F, Li J-J, Zhang Y, Wu Z-Y, Xu Y-H (2026) Analysis of the Type VI secretion system and microbiological characteristics of hypervirulent Klebsiella pneumoniae causing urinary tract infections. J Infect Dev Ctries 20:70–78. doi: 10.3855/jidc.21628

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Issue

Vol. 20 No. 01: January 2026

Section

Original Articles

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