Comparative infectivity, virulence and molecular epidemiology of MDR and XDR Acinetobacter baumannii isolates
Jale Boral1, Chaitanya Tellapragada2, Oskar Thofte1
1Clinical Microbiology, Department of Translational Medicine, Lund University, Malmö, Sweden.
Background:
Multidrug resistant Acinetobacter baumannii remains a global concern with its ability to adhere, disperse and sustain in areas involving suboptimal infection control measures, particularly in war areas. In this study we aimed to evaluate the susceptibility profiles, molecular epidemiology and pathogenesis of A. baumannii isolates from conflict zones in Ukraine.
Methods:
A. baumannii wound isolates (n=46) were tested to comparatively assess antimicrobial resistance, molecular epidemiology, pathogenesis and infectivity. Briefly, antimicrobial susceptibility testing, whole genome sequencing, biofilm and capsule formation, as well as serum survival and bacterial viability in G. mellonella and a mouse infection model were performed.
Results:
Dominating sequence types were ST2, ST19, ST78 and ST400 while 65.21% of isolates were from international clones. All isolates were multidrug resistant (MDR), and 7 isolates were extensively drug resistant (XDR). ST19 isolates had higher encapsulation, lower serum survival and missing T6SS, omp33-36 and biofilm production associated genes. However, bacteria expressed higher virulence and lethality during early infection compared to later stages in vivo.
Conclusion:
We report the first results characterizing the pathogenesis and infectivity of the emerging A. baumannii ST19. High MDR and XDR rates alongside clonally related isolates are concerning and highlight the importance of infection prevention and control measures in conflict zones.
Insights
Multidrug-resistant Acinetobacter baumannii strains from Ukraine exhibit high resistance rates. Emerging ST19 strains show significant virulence and lethality, underscoring the need for enhanced infection control in conflict zones.
Area of Science:
- Microbiology
- Infectious Diseases
- Epidemiology
Background:
- Multidrug-resistant Acinetobacter baumannii poses a global health threat, particularly in areas with compromised infection control.
- Conflict zones present unique challenges for managing Acinetobacter baumannii infections due to its resilience and adaptability.
Purpose of the Study:
- To investigate the antimicrobial susceptibility, molecular epidemiology, and pathogenesis of Acinetobacter baumannii isolates from Ukrainian conflict zones.
- To characterize the virulence and infectivity of emerging sequence types, specifically ST19.
Main Methods:
- Antimicrobial susceptibility testing and whole genome sequencing were performed on 46 Acinetobacter baumannii wound isolates.
- Pathogenesis and infectivity were assessed through biofilm and capsule formation assays, serum survival tests, and in vivo models (G. mellonella and mice).
Main Results:
- All isolates were multidrug-resistant (MDR), with 7 also being extensively drug-resistant (XDR). Dominant sequence types included ST2, ST19, ST78, and ST400.
- ST19 isolates displayed increased encapsulation, reduced serum survival, and lacked key virulence genes (T6SS, omp33-36, biofilm).
- Despite genetic differences, ST19 exhibited high virulence and lethality in early-stage infections.
Conclusions:
- This study provides the first characterization of Acinetobacter baumannii ST19 pathogenesis and infectivity.
- High rates of MDR and XDR, along with clonal relatedness, emphasize the critical need for robust infection prevention and control in conflict settings.
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