Acinetobacter baumannii NCIMB8209: A rare environmental strain displaying extensive insertion sequence-mediated genome remodeling resulting in the loss of exposed cell structures and defensive mechanisms
| Autor: | Bruno Alejandro Steimbrüch, Martín Espariz, Howard A. Shuman, Juan Ignacio Díaz Miloslavich, Joana L. Seravalle, Alejandro M. Viale, Guillermo Daniel Repizo |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Acinetobacter baumannii
lcsh:QR1-502 virulence factors comparative genomics medicine.disease_cause Genome lcsh:Microbiology Clinical Science and Epidemiology purl.org/becyt/ford/1 [https] Plasmid Drug Resistance Multiple Bacterial Environmental Microbiology CRISPR Insertion sequence Phylogeny Genetics education.field_of_study 0303 health sciences biology Phylogenetic tree Genomics Plants QR1-502 Anti-Bacterial Agents 3. Good health environmental Acinetobacter baumannii VIRULENCE FACTORS Research Article COMPARATIVE GENOMICS Genomic Islands ENVIRONMENTAL RESERVOIRS Population PREANTIBIOTIC-ERA ACINETOBACTER BAUMANNII Virulence Microbiology 03 medical and health sciences Antibiotic resistance ENVIRONMENTAL ACINETOBACTER BAUMANNII medicine education purl.org/becyt/ford/1.6 [https] Molecular Biology Gene 030304 developmental biology Comparative genomics Whole Genome Sequencing Pseudomonas aeruginosa INSERTION SEQUENCES 030306 microbiology Genetic Variation biochemical phenomena metabolism and nutrition preantibiotic-era Acinetobacter baumannii bacterial infections and mycoses biology.organism_classification insertion sequences Genes Bacterial bacteria environmental reservoirs |
| Zdroj: | CONICET Digital (CONICET) Consejo Nacional de Investigaciones Científicas y Técnicas instacron:CONICET mSphere, Vol 5, Iss 4 (2020) mSphere, Vol 5, Iss 4, p e00404-20 (2020) mSphere |
| DOI: | 10.1101/2020.04.30.071514 |
| Popis: | Acinetobacter baumannii is an ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) opportunistic pathogen, with poorly defined natural habitats/reservoirs outside the clinical setting. A. baumannii arose from the Acinetobacter calcoaceticus-A. baumannii complex as the result of a population bottleneck, followed by a recent population expansion from a few clinically relevant clones endowed with an arsenal of resistance and virulence genes. Still, the identification of virulence traits and the evolutionary paths leading to a pathogenic lifestyle has remained elusive, and thus, the study of nonclinical (“environmental”) A. baumannii isolates is necessary. We conducted here comparative genomic and virulence studies on A. baumannii NCMBI8209 isolated in 1943 from the microbiota responsible for the decomposition of guayule, and therefore well differentiated both temporally and epidemiologically from the multidrug-resistant strains that are predominant nowadays. Our work provides insights on the adaptive strategies used by A. baumannii to escape from host defenses and may help the adoption of measures aimed to limit its further dissemination. Acinetobacter baumannii represents nowadays an important nosocomial pathogen of poorly defined reservoirs outside the clinical setting. Here, we conducted whole-genome sequencing analysis of the Acinetobacter sp. NCIMB8209 collection strain, isolated in 1943 from the aerobic degradation (retting) of desert guayule shrubs. Strain NCIMB8209 contained a 3.75-Mb chromosome and a plasmid of 134 kb. Phylogenetic analysis based on core genes indicated NCIMB8209 affiliation to A. baumannii, a result supported by the identification of a chromosomal blaOXA-51-like gene. Seven genomic islands lacking antimicrobial resistance determinants, 5 regions encompassing phage-related genes, and notably, 93 insertion sequences (IS) were found in this genome. NCIMB8209 harbors most genes linked to persistence and virulence described in contemporary A. baumannii clinical strains, but many of the genes encoding components of surface structures are interrupted by IS. Moreover, defense genetic islands against biological aggressors such as type 6 secretion systems or CRISPR-cas are absent from this genome. These findings correlate with a low capacity of NCIMB8209 to form biofilm and pellicle, low motility on semisolid medium, and low virulence toward Galleria mellonella and Caenorhabditis elegans. Searching for catabolic genes and concomitant metabolic assays revealed the ability of NCIMB8209 to grow on a wide range of substances produced by plants, including aromatic acids and defense compounds against external aggressors. All the above features strongly suggest that NCIMB8209 has evolved specific adaptive features to a particular environmental niche. Moreover, they also revealed that the remarkable genetic plasticity identified in contemporary A. baumannii clinical strains represents an intrinsic characteristic of the species. IMPORTANCE Acinetobacter baumannii is an ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) opportunistic pathogen, with poorly defined natural habitats/reservoirs outside the clinical setting. A. baumannii arose from the Acinetobacter calcoaceticus-A. baumannii complex as the result of a population bottleneck, followed by a recent population expansion from a few clinically relevant clones endowed with an arsenal of resistance and virulence genes. Still, the identification of virulence traits and the evolutionary paths leading to a pathogenic lifestyle has remained elusive, and thus, the study of nonclinical (“environmental”) A. baumannii isolates is necessary. We conducted here comparative genomic and virulence studies on A. baumannii NCMBI8209 isolated in 1943 from the microbiota responsible for the decomposition of guayule, and therefore well differentiated both temporally and epidemiologically from the multidrug-resistant strains that are predominant nowadays. Our work provides insights on the adaptive strategies used by A. baumannii to escape from host defenses and may help the adoption of measures aimed to limit its further dissemination. |
| Databáze: | OpenAIRE |
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