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Characterization of R plasmids from Shigella sonnei in Taiwan
C Y Chang1, L L Chang, S R Lin
1Department of Microbiology, Kaohsiung Medical College, Taiwan, Republic of China.
Abstract:
Plasmids of 70MDa from 6 Shigella sonnei isolates originating in Kaohsiung, Taiwan were found. All of them encoded resistance to chloramphenicol and tetracycline. These plasmids belonged to the H II incompatibility group. The fertility inhibition property of plasmids was the fi- type. Restriction endonuclease analysis revealed the six plasmids all had identical restriction patterns with BamH I, Hind III and Nru I. All six plasmids carried the type I chloramphenicol acetyltransferase gene and the class B tetracycline resistance gene as determined by Southern hybridization with DNA probes of various antimicrobial resistance genes. The results demonstrated that S. sonnei isolates harboured the same R plasmid.
Insights
Six Shigella sonnei isolates from Taiwan carried identical 70MDa plasmids conferring resistance to chloramphenicol and tetracycline. These findings highlight the prevalence of specific antimicrobial resistance plasmids in bacterial populations.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Shigella sonnei is a significant cause of bacterial dysentery.
- Antimicrobial resistance in bacterial pathogens is a growing global health concern.
- Plasmids are key vehicles for the dissemination of antibiotic resistance genes.
Purpose of the Study:
- To characterize the plasmids found in Shigella sonnei isolates from Kaohsiung, Taiwan.
- To determine the genetic basis of antimicrobial resistance encoded by these plasmids.
- To investigate the relatedness of the identified plasmids.
Main Methods:
- Plasmid DNA isolation and size determination (70MDa).
- Incompatibility grouping (H II) and fertility inhibition typing (fi-).
- Restriction endonuclease analysis (BamH I, Hind III, Nru I).
- Southern hybridization using DNA probes for antimicrobial resistance genes (catI, tetB).
Main Results:
- Six Shigella sonnei isolates harbored identical 70MDa plasmids.
- All plasmids conferred resistance to chloramphenicol and tetracycline.
- Plasmids belonged to the H II incompatibility group and were of fi- type.
- Identical restriction patterns and carriage of type I chloramphenicol acetyltransferase (catI) and class B tetracycline resistance (tetB) genes were confirmed.
Conclusions:
- The study identified a common R plasmid in Shigella sonnei isolates from Taiwan.
- This R plasmid carries genes for resistance to chloramphenicol and tetracycline.
- The findings suggest clonal spread or efficient horizontal transfer of this specific R plasmid.