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Molecular epidemiology and comparative virulence patterns of Acinetobacter baumannii isolates from war-related injuries in Ukraine

Boral, Jale LU orcid ; Tellapragada, Chaitanya ; Thofte, Oskar LU orcid ; Öhnström, Valdemar LU orcid ; Magda, Michal LU orcid ; Matuschek, Erika ; Nazarchuk, Oleksandr ; Giske, Christian G. ; Blom, Anna LU orcid and Riesbeck, Kristian LU orcid (2025) In Immunobiology
Abstract
Abstract
Background:
Multidrug-resistant Acinetobacter baumannii remains as a global concern with its ability to adhere, disperse and sustain on areas involving suboptimal infection control measures, especially war zones. We aimed to evaluate the molecular epidemiology and virulence factors of A. baumannii isolates from conflict zone in Ukraine.
Methods:
In 2022, 46 A. baumannii wound isolates were received from war-related injuries in Ukraine. Antimicrobial susceptibility testing and whole genome sequencing were performed to all isolates (n=46). The resistome, virulome, K- and O-types of isolates were detected using VFDB and Kaptive 2.0, respectively. Virulence traits of the isolates were tested in vitro and in vivo by... (More)
Abstract
Background:
Multidrug-resistant Acinetobacter baumannii remains as a global concern with its ability to adhere, disperse and sustain on areas involving suboptimal infection control measures, especially war zones. We aimed to evaluate the molecular epidemiology and virulence factors of A. baumannii isolates from conflict zone in Ukraine.
Methods:
In 2022, 46 A. baumannii wound isolates were received from war-related injuries in Ukraine. Antimicrobial susceptibility testing and whole genome sequencing were performed to all isolates (n=46). The resistome, virulome, K- and O-types of isolates were detected using VFDB and Kaptive 2.0, respectively. Virulence traits of the isolates were tested in vitro and in vivo by phenotypic assays; capsule abundance, serum survival, biofilm formation, Galleria mellonella infection and mouse pneumonia.
Results:
Five out of 46 (10.8%) isolates tested extensively drug resistant (XDR) and 84.78% of the isolates tested multidrug-resistant (MDR). Distance matrix analysis based on SNPs generated 5 main clusters of 46 isolates. Dominating sequence types of the isolates were ST2 (19%), ST19 (19%), ST400 (19%) and ST78 (19%). Comparative assessment of virulence profiling revealed that, KL235 and K91 are highly encapsulated K types and are found in ST2 and ST19 isolates. Virulome analysis revealed missing T66S encoding genes, Omp33-36 and biofilm production related genes (bap, blp1) in ST19 isolates. High level of encapsulation was observed in ST19 isolates followed by lower serum survival compared to the rest of the study cohort. ST19 isolates expressed a higher survival and virulence score at 24 h in mice and G. mellonella viability assay, respectively. However, prolonged infection up to 120 h in G. mellonella larvae and 72 h in mice showed that ST19 isolates have lower ability to kill larvae followed by clearance in lung and BAL fluid while ST2 isolates managed to persist the infection and lethality (p=0.0001).
Conclusion:
Although A. baumannii is known for its strain specific behavioral pattern in terms of virulence, our study revealed that STs act parallel on genotypic and phenotypic basis. Instability and absence of TS66, OMP-33/36 and biofilm encoding genes and its effect on encapsulation should be studied further for possible antivirulent and immunization therapies.
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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Immunobiology
article number
152926
publisher
Elsevier
ISSN
1878-3279
DOI
10.1016/j.imbio.2025.152926
language
English
LU publication?
yes
id
10b8b86b-fff4-4e4f-aa8c-0c1be9d11827
date added to LUP
2026-08-26 14:26:50
date last changed
2026-08-27 09:16:42
@misc{10b8b86b-fff4-4e4f-aa8c-0c1be9d11827,
  abstract     = {{Abstract<br/>Background:<br/>Multidrug-resistant Acinetobacter baumannii remains as a global concern with its ability to adhere, disperse and sustain on areas involving suboptimal infection control measures, especially war zones. We aimed to evaluate the molecular epidemiology and virulence factors of A. baumannii isolates from conflict zone in Ukraine.<br/>Methods:<br/>In 2022, 46 A. baumannii wound isolates were received from war-related injuries in Ukraine. Antimicrobial susceptibility testing and whole genome sequencing were performed to all isolates (n=46). The resistome, virulome, K- and O-types of isolates were detected using VFDB and Kaptive 2.0, respectively. Virulence traits of the isolates were tested in vitro and in vivo by phenotypic assays; capsule abundance, serum survival, biofilm formation, Galleria mellonella infection and mouse pneumonia.<br/>Results:<br/>Five out of 46 (10.8%) isolates tested extensively drug resistant (XDR) and 84.78% of the isolates tested multidrug-resistant (MDR). Distance matrix analysis based on SNPs generated 5 main clusters of 46 isolates. Dominating sequence types of the isolates were ST2 (19%), ST19 (19%), ST400 (19%) and ST78 (19%). Comparative assessment of virulence profiling revealed that, KL235 and K91 are highly encapsulated K types and are found in ST2 and ST19 isolates. Virulome analysis revealed missing T66S encoding genes, Omp33-36 and biofilm production related genes (bap, blp1) in ST19 isolates. High level of encapsulation was observed in ST19 isolates followed by lower serum survival compared to the rest of the study cohort. ST19 isolates expressed a higher survival and virulence score at 24 h in mice and G. mellonella viability assay, respectively. However, prolonged infection up to 120 h in G. mellonella larvae and 72 h in mice showed that ST19 isolates have lower ability to kill larvae followed by clearance in lung and BAL fluid while ST2 isolates managed to persist the infection and lethality (p=0.0001).<br/>Conclusion:<br/>Although A. baumannii is known for its strain specific behavioral pattern in terms of virulence, our study revealed that STs act parallel on genotypic and phenotypic basis. Instability and absence of TS66, OMP-33/36 and biofilm encoding genes and its effect on encapsulation should be studied further for possible antivirulent and immunization therapies.<br/>}},
  author       = {{Boral, Jale and Tellapragada, Chaitanya and Thofte, Oskar and Öhnström, Valdemar and Magda, Michal and Matuschek, Erika and Nazarchuk, Oleksandr and Giske, Christian G. and Blom, Anna and Riesbeck, Kristian}},
  issn         = {{1878-3279}},
  language     = {{eng}},
  note         = {{Conference Abstract}},
  publisher    = {{Elsevier}},
  series       = {{Immunobiology}},
  title        = {{Molecular epidemiology and comparative virulence patterns of <i>Acinetobacter baumannii</i> isolates from war-related injuries in Ukraine}},
  url          = {{http://dx.doi.org/10.1016/j.imbio.2025.152926}},
  doi          = {{10.1016/j.imbio.2025.152926}},
  year         = {{2025}},
}