Identification of NDM-1 in a Putatively Novel Acinetobacter Species ("NB14") Closely Related to Acinetobacter pittii

Area of Science:

• Molecular microbiology and infectious diseases.
• Antimicrobial resistance and bacterial genomics.

Background:

• The emergence of carbapenem resistance in Acinetobacter species poses a significant global health threat.
• The blaNDM-1 gene is a major determinant of carbapenem resistance, frequently found on mobile genetic elements.

Purpose of the Study:

• To molecularly characterize a blaNDM-1-positive Acinetobacter clinical isolate from Turkey.
• To investigate the genetic context and potential dissemination of the blaNDM-1 gene within Acinetobacter populations.

Main Methods:

• Amplified 16S ribosomal DNA restriction analysis (ARDRA) for species identification.
• Molecular sequencing techniques to confirm species and characterize the blaNDM-1 gene.
• Plasmid analysis to determine its location and conjugative potential.

Main Results:

• Identification of a distinct Acinetobacter clinical isolate from Turkey, potentially representing a novel species based on ARDRA and sequencing.
• The blaNDM-1 gene was located on a conjugative plasmid within this isolate.
• This plasmid was found to be prevalent among non-baumannii Acinetobacter isolates in the study population.

Conclusions:

• A novel Acinetobacter species harboring blaNDM-1 has been identified, indicating a new reservoir for carbapenem resistance.
• The presence of blaNDM-1 on a conjugative plasmid suggests a high risk of horizontal gene transfer.
• This resistance determinant may spread among Acinetobacter species, including clinically significant ones like A. baumannii, posing future therapeutic challenges.