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Isolation and characterization of two plasmids in a clinical Acinetobacter nosocomialis strain
Bianca Gifford, Joseph Tucci, Simon J McIlroy
1La Trobe Institute for Molecular Sciences, La Trobe University, Bendigo, Australia. steve.petrovski18@gmail.com.
Background:
Acinetobacter species are recognised as important nosocomial pathogens that have become a major cause of invasive opportunistic infections in hospitalised patients. Their clinical significance is largely due to the rapid development of antimicrobial resistance among strains. The development of antibiotic resistance among bacterial strains occurs frequently by the acquisition of resistance genes by gene transfer systems such as bacterial plasmids.
Method:
Multi-antibiotic resistant Acinetobacter nosocomialis strain 178 was isolated from a hospital in Melbourne, Australia. This strain was screened for the presence of plasmids. The two plasmids isolated were sequenced and annotated.
Results:
Two plasmids isolated from a single clinical Acinetobacter nosocomialis strain were sequenced. One plasmid, designated pRAY*-v3, appears to have evolved via the same lineage as the pRAY plasmid isolated from an Acinetobacter baumannii in South Africa. The other plasmid, designated pAB49-v1, appears to be an evolutionary descendent from a cryptic plasmid isolated from an A. baumannii almost 20 years ago. Both of the plasmid sequences here share a high level of sequence similarity with their ancestors, however differences are noted.
Conclusion:
The isolation of these plasmid-lineages across different decades and continents suggests their global dissemination.
Insights
Two plasmids from a multi-drug resistant Acinetobacter nosocomialis strain show high similarity to older plasmid lineages, suggesting global spread of these important hospital pathogens.
Area of Science:
- Microbiology
- Genomics
- Infectious Diseases
Background:
- Acinetobacter species are significant hospital-acquired pathogens causing opportunistic infections.
- Rapid development of antimicrobial resistance in Acinetobacter strains is a major clinical concern.
- Bacterial plasmids frequently mediate the acquisition of antibiotic resistance genes.
Purpose of the Study:
- To investigate the genetic makeup of plasmids harbored by a multi-antibiotic resistant Acinetobacter nosocomialis strain.
- To understand the evolutionary history and dissemination potential of these plasmids.
Main Methods:
- Isolation of a multi-antibiotic resistant Acinetobacter nosocomialis strain (strain 178) from a hospital in Melbourne, Australia.
- Screening the isolate for the presence of plasmids.
- Sequencing and annotation of two isolated plasmids.
Main Results:
- Two plasmids, pRAY*-v3 and pAB49-v1, were sequenced from the clinical isolate.
- pRAY*-v3 shares an evolutionary lineage with a previously identified plasmid from Acinetobacter baumannii.
- pAB49-v1 is an evolutionary descendant of a cryptic plasmid from Acinetobacter baumannii isolated nearly 20 years prior.
- Both sequenced plasmids exhibit high sequence similarity to their ancestral counterparts, with notable differences.
Conclusions:
- The identified plasmid lineages have been isolated across different continents and decades.
- This suggests a global dissemination pattern for these specific plasmid types.
- The findings highlight the persistent evolution and spread of antibiotic resistance mechanisms in Acinetobacter species.
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