Molecular typing of Klebsiella pneumoniae isolates from a neonatal intensive care unit
Related Experiment Videos
M Marranzano1, A Agodi, M Romeo
1Institute of Hygiene and Preventive Medicine, University of Catania, Italy.
Abstract:
The epidemiological features of 60 multiresistant K. pneumoniae strains isolated from 1991 to 1995 in a neonatal ward are described. Antibiotic. Susceptibility testing and plasmid profile analysis were used as subtyping procedures. Antibiotic susceptibility typing was not informative enough since discrimination among isolates was typically poor. Plasmid profile analysis demonstrated that 58 out of 60 strains harboured one or more plasmid DNA bands, of different molecular weights ranging between 1.8 and 150 Mda. Small plasmids were best visualized after the alkaline lysis procedure, while large plasmids by the Kado and Liu method. A combination of plasmid patterns obtained by the two extraction procedures was used to define the final plasmid profile for each strain. Thirteen different plasmid profiles were identified among the collection of K. pneumoniae isolates from newborn patients of the same intensive care unit. The investigation showed that the strains were not responsible for a single outbreak.
Insights
Multiresistant Klebsiella pneumoniae strains in a neonatal ward showed diverse plasmid profiles, indicating they were not from a single outbreak. Plasmid analysis proved more effective than antibiotic susceptibility testing for strain differentiation.
Area of Science:
- Microbiology
- Epidemiology
- Molecular Biology
Background:
- Multiresistant Klebsiella pneumoniae poses a significant threat in healthcare settings, particularly neonatal intensive care units.
- Understanding the genetic relatedness of K. pneumoniae strains is crucial for infection control and outbreak investigation.
Purpose of the Study:
- To describe the epidemiological features of multiresistant K. pneumoniae strains isolated from a neonatal ward.
- To evaluate the utility of plasmid profile analysis and antibiotic susceptibility testing for subtyping these strains.
- To determine if the isolated strains originated from a single outbreak.
Main Methods:
- Collected 60 multiresistant K. pneumoniae strains from a neonatal ward between 1991 and 1995.
- Performed antibiotic susceptibility testing for strain discrimination.
- Utilized alkaline lysis and Kado and Liu methods for plasmid DNA extraction and analysis.
- Combined plasmid patterns from both extraction methods to define strain profiles.
Main Results:
- Antibiotic susceptibility testing provided poor discrimination among isolates.
- Plasmid profile analysis revealed that 58 out of 60 strains contained one or more plasmids (1.8–150 Mda).
- Thirteen distinct plasmid profiles were identified among the K. pneumoniae isolates.
- The strains were determined not to be responsible for a single outbreak.
Conclusions:
- Plasmid profile analysis is a valuable tool for differentiating K. pneumoniae strains in a clinical setting.
- The diverse plasmid profiles suggest multiple independent introductions or transmissions of K. pneumoniae strains into the neonatal ward.
- Findings indicate the absence of a single clonal outbreak during the study period.