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R-factor responsible for an outbreak of multiply antibiotic-resistant Klebsiella pneumoniae
Abstract:
Seven serotypes of Klebsiella pneumoniae isolated from different patients demonstrated resistance to the same eight antibiotics. A plasmid carrying resistance determinants to these antibiotics and mercury salts could be transferred in toto to a plasmidless strain of Escherichia coli. All E. coli transconjugants showed the same antibiotic resistance pattern. Digestion with restriction endonucleases yielded patterns that were identical for each of the R-factor transferred from the multiply resistant serotypes. Moreover, deoxyribonucleic acid-deoxyribonucleic acid hybridization demonstrated identity between the probe, pMAC20 (an R-factor from one serotype), and all R-factors isolated from the multiply resistant strains of K. pneumoniae and the E. coli transconjugants tested.
Insights
Multiple Klebsiella pneumoniae strains share a transferable plasmid conferring antibiotic and mercury resistance. This R-factor was identical across strains and successfully transferred to E. coli, maintaining resistance patterns.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Antibiotic resistance in Klebsiella pneumoniae is a growing public health concern.
- Multiple drug resistance (MDR) in bacteria poses significant treatment challenges.
- Understanding the genetic basis of MDR is crucial for developing effective control strategies.
Purpose of the Study:
- To investigate the genetic basis of antibiotic resistance in multiple Klebsiella pneumoniae serotypes.
- To determine if a common resistance mechanism is responsible for the observed MDR.
- To characterize the transferability and identity of resistance determinants.
Main Methods:
- Isolation and characterization of Klebsiella pneumoniae serotypes from clinical samples.
- Antibiotic susceptibility testing against a panel of eight antibiotics.
- Plasmid DNA extraction and transfer experiments to a plasmidless Escherichia coli strain.
- Restriction endonuclease digestion of plasmid DNA.
- DNA-DNA hybridization using a specific R-factor probe (pMAC20).
Main Results:
- Seven Klebsiella pneumoniae serotypes exhibited identical resistance to eight antibiotics.
- A single plasmid carrying resistance to these antibiotics and mercury salts was identified.
- This R-factor was successfully transferred to Escherichia coli, conferring the same resistance profile.
- Restriction enzyme digestion and DNA-DNA hybridization confirmed the identity of the R-factors across all strains and transconjugants.
Conclusions:
- A common, transferable R-factor is responsible for the multidrug resistance observed in these Klebsiella pneumoniae isolates.
- The R-factor is conserved among different serotypes, suggesting horizontal gene transfer.
- This finding highlights the potential for rapid dissemination of antibiotic resistance within bacterial populations.