Microbial Bioactives
Microbial Bioactives | Online ISSN 2209-2161
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Volume 9 Number 1 2026
REVIEWS (Open Access)
Hypervirulent Acinetobacter baumannii: A Systematic Review and Meta-Analysis of Virulence Mechanisms and Antimicrobial Resistance
Kai Song 1*, Shuquan Xin 1*, Benkang Xie 1*
Microbial Bioactives 9 (1) 1-8 https://doi.org/10.25163/microbbioacts.9110609
Submitted: 17 October 2025 Revised: 11 January 2026 Accepted: 19 January 2026 Published: 21 January 2026
Abstract
The emergence of hypervirulent Acinetobacter baumannii (hvAB) represents a critical global health threat due to its unique combination of multidrug resistance (MDR) and enhanced virulence. These strains have transformed a traditionally opportunistic pathogen into a formidable agent of healthcare-associated infections, causing bloodstream infections, ventilator-associated pneumonia, and meningitis with mortality rates as high as 50–70%. The convergence of resistance and virulence in hvAB is facilitated by horizontal gene transfer, mobile genetic elements, and shared regulatory networks, including two-component systems such as PmrAB and BfmRS. Virulence factors, including capsule formation, biofilm development, iron acquisition via siderophores, and membrane permeability modifications, provide survival advantages against host immunity and antimicrobial therapy. This systematic review and meta-analysis synthesize data from in vitro, in vivo, and clinical studies to evaluate the prevalence of hvAB, mechanisms driving resistance and virulence, and the efficacy of emerging therapeutic strategies. Meta-analytic techniques were applied to quantify associations between specific virulence determinants and clinical outcomes. Furthermore, innovative non-antibiotic approaches, including therapeutic vaccines, phage therapy, anti-virulence compounds, and siderophore-based strategies, were assessed for their potential to mitigate infections. Findings underscore the urgent need for integrated surveillance, rapid diagnostics, and alternative therapeutics targeting both resistance and virulence pathways. By providing a comprehensive overview, this study aims to inform clinical management, guide research priorities, and support the development of novel interventions to combat this evolving pathogen.
Keywords: Acinetobacter baumannii; Hypervirulence; Multidrug resistance; Biofilm; Siderophores; Two-component systems; Antimicrobial strategies
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