Specific and rapid identification of multiple-antibiotic resistant Pseudomonas aeruginosa clones isolated in an intensive care unit

Area of Science:

• Microbiology
• Infectious Diseases
• Molecular Biology

Background:

• Multiple-antibiotic-resistant Pseudomonas aeruginosa (MDR-PA) poses a significant threat in intensive care units (ICUs).
• Parallel acquisition of antibiotic resistance in bacterial strains often suggests a common clonal origin, complicating infection control efforts.

Purpose of the Study:

• To investigate the clonal relationship of seventeen MDR-PA isolates from two ICU patients.
• To determine if observed parallel resistance patterns indicated cross-infection or a shared strain.

Main Methods:

• Biotyping, serotyping, and plasmid profiling were initially used for strain characterization.
• Polymerase Chain Reaction (PCR)-based techniques and macrorestriction analysis (MRA) were employed for high-resolution typing.
• Comparative genomic analysis was performed to assess strain relatedness.

Main Results:

• Conventional typing methods (biotyping, serotyping, plasmid profiling) failed to accurately differentiate the strains.
• Advanced molecular techniques, specifically PCR and MRA, successfully distinguished unique clones.
• Each patient was infected with a distinct multidrug-resistant strain of P. aeruginosa.

Conclusions:

• The parallel acquisition of antibiotic resistance was coincidental and not due to a common clonal origin.
• There was no evidence of cross-infection or reinfection with a new strain between the two patients.
• Accurate strain typing using molecular methods is crucial for effective infection control in healthcare settings.