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Meta-Analysis
. 2025 Dec;14(1):2438657.
doi: 10.1080/22221751.2024.2438657. Epub 2024 Dec 16.

Antimicrobial resistance in hypermucoviscous and non-hypermucoviscous Klebsiella pneumoniae: a systematic review and meta-analysis

Hiroki Namikawa  1 , Ken-Ichi Oinuma  2   3 , Yukihiro Kaneko  2   3 , Hiroshi Kakeya  3   4 , Taichi Shuto  1
Affiliations
Meta-Analysis

Antimicrobial resistance in hypermucoviscous and non-hypermucoviscous Klebsiella pneumoniae: a systematic review and meta-analysis

Hiroki Namikawa et al. Emerg Microbes Infect. 2025 Dec.

Abstract

Antimicrobial resistance has recently increased due to emerging carbapenem-resistant Klebsiella pneumoniae and extended-spectrum β-lactamase (ESBL)-producing strains of K. pneumoniae, especially among hypermucoviscous K. pneumoniae (hmKp) strains. To evaluate the prevalence of ESBL-producing and carbapenem-resistant strains in hmKp and non-hmKp clinical isolates through a systematic review and meta-analysis. We searched PubMed, Scopus, and Cochrane Library databases from January 2000 to June 2023. Clinical and in vivo/in vitro studies involving confirmed K. pneumoniae clinical isolates differentiated into hmKP and non-hmKP strains based on string test results. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated based on the number of individuals in each target group. Forest plots were used to visualize the effect sizes and 95% CIs of individual studies estimated using the inverse variance and DerSimonian - Laird methods with fixed - and random-effects models, respectively. Heterogeneity was assessed using Cochran's Q test (I2 ≥ 50%). Fifteen studies comprising 2049 clinical isolates of K. pneumoniae met the inclusion criteria. Meta-analysis revealed that hmKp strains were associated with a significantly lower prevalence of ESBL-producing strains (pooled OR: 0.26, 95% CI: 0.11-0.63, P = 0.003) and a slightly lower prevalence of carbapenem-resistant strains than non-hmKp strains (pooled OR: 0.63, 95% CI: 0.40-0.97, P = 0.038). hmKp strains exhibited lower and slightly lower prevalence of ESBL production and carbapenem resistance, respectively, than non-hmKp strains. However, given the rising prevalence of ESBL-producing and carbapenem-resistant hmKp strains, patients infected by string-test-positive K. pneumoniae must be managed prudently, considering the potential for highly resistant strains.

Keywords: Klebsiella pneumoniae; antimicrobial resistance; carbapenem-resistant; extended-spectrum beta-lactamase; hypermucoviscous.

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Conflict of interest statement

No potential conflict of interest was reported by the author(s).

Figures

Figure 1.
Figure 1.
Flow diagram illustrating the process of selecting the studies included in this review.
Figure 2.
Figure 2.
Forest plot of the odds ratios for differences in the prevalence of (a) extended-spectrum β-lactamase-producing and (b) carbapenem-resistant strains in clinical isolates of hypermucoviscous Klebsiella pneumoniae (hmKp) and non-hmKp.
Figure 3.
Figure 3.
Funnel plot of the odds ratios for (a) extended-spectrum β-lactamase-producing and (b) carbapenem-resistant strains.
See this image and copyright information in PMC

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