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Molecular characterization of a multiply resistant Klebsiella pneumoniae encoding ESBLs and a plasmid-mediated AmpC
N D Hanson1, K S Thomson, E S Moland
1Center for Research in Anti-Infectives and Biotechnology, Department of Pediatrics, Creighton University School of Medicine and Methodist Hospital, Omaha, NE 68178, USA. ndhanson@creighton.edu
Abstract:
Organisms encoding multiple antibiotic resistance genes are becoming increasingly prevalent. In this report we describe a multiply resistant Klebsiella pneumoniae which possesses at least five different beta-lactamase genes. Isoelectric focusing, polymerase chain reaction and restriction fragment length polymorphism analysis identified TEM-1, multiple SHVs, OXA-9 and a plasmid-mediated ampC, beta-lactamase. Furthermore, Southern analysis and conjugation experiments established that most of the resistance genes were encoded on one large transferable plasmid. This report demonstrates the complexity of multiply resistant organisms.
Insights
This study identifies a multiply resistant Klebsiella pneumoniae strain harboring at least five beta-lactamase genes. Most resistance genes were located on a single, transferable plasmid, highlighting the complexity of antibiotic resistance.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Increasing prevalence of organisms with multiple antibiotic resistance genes.
- Klebsiella pneumoniae as a significant opportunistic pathogen.
- The growing threat of antimicrobial resistance.
Purpose of the Study:
- To characterize a multiply resistant Klebsiella pneumoniae strain.
- To identify the specific beta-lactamase genes present.
- To determine the genetic basis of multidrug resistance in this isolate.
Main Methods:
- Isoelectric focusing to analyze beta-lactamase profiles.
- Polymerase chain reaction (PCR) for gene identification.
- Restriction fragment length polymorphism (RFLP) analysis.
- Southern blot hybridization and conjugation experiments for plasmid analysis.
Main Results:
- Identification of TEM-1, multiple SHV variants, OXA-9, and a plasmid-mediated ampC beta-lactamase gene.
- Confirmation that most resistance genes are located on a single large plasmid.
- Demonstration of the plasmid's transferability via conjugation.
Conclusions:
- The characterized Klebsiella pneumoniae strain exhibits complex multidrug resistance.
- A single transferable plasmid can carry multiple beta-lactamase genes, facilitating rapid resistance dissemination.
- Understanding such complex resistance mechanisms is crucial for combating antimicrobial resistance.