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[Plasmid analysis and antibiotic resistance pattern measurement of Shigella in Chengdu]
Abstract:
A total of 81 strains of Shigella isolated from sporadic cases and cases in an outbreak of Shigella sonnei infection was analysed by plasmid profiles and antibiotic resistance patterns. The strains had a high resistance patterns. The strains had a high resistance of ampicillin, tetracycline, trimethoprim-sulfamethoxazole and chloramphenicol; while 97.2% of the strains were susceptible to gentamicin, kanamycin. The results showed that 50% of the strains harbored plasmid patterns within each species, which indicated that many genetically different strains of Shigella were responsible for dysentery epidemics in Chengdu. According to the results of the plasmid analysis and antibiotic resistance pattern measurement made in the outbreak strains, it was clearly seen that most of the strains were similar or fundamentally similar, which suggested that one or two strains with genetical homology were the main causative agent for the outbreak. We think that plasmid profiles and antibiotic resistance patterns are applicable to the identification of the outbreak strains of dysentery as an efficient epidemiologic tool.
Insights
This study analyzed Shigella sonnei strains, revealing high resistance to common antibiotics like ampicillin and tetracycline. Plasmid profiling and antibiotic resistance patterns proved effective tools for identifying outbreak strains and understanding dysentery epidemics.
Area of Science:
- Microbiology
- Epidemiology
- Molecular Biology
Background:
- Shigella sonnei causes dysentery outbreaks, necessitating effective identification methods.
- Understanding antibiotic resistance patterns is crucial for managing infections.
Purpose of the Study:
- To analyze plasmid profiles and antibiotic resistance patterns of Shigella sonnei strains.
- To determine the genetic relatedness of strains causing sporadic and outbreak infections.
- To evaluate the utility of these methods as epidemiologic tools.
Main Methods:
- Plasmid profiling of 81 Shigella sonnei isolates.
- Antibiotic resistance pattern determination using standard antimicrobial susceptibility testing.
- Comparative analysis of sporadic and outbreak strains.
Main Results:
- High resistance observed for ampicillin, tetracycline, trimethoprim-sulfamethoxazole, and chloramphenicol.
- Susceptibility to gentamicin and kanamycin was high (97.2%).
- 50% of strains harbored plasmids, indicating diverse genetic origins in epidemics.
- Outbreak strains showed significant similarity, suggesting a common genetic source.
Conclusions:
- Plasmid profiles and antibiotic resistance patterns are valuable for identifying Shigella outbreak strains.
- These methods aid in understanding the epidemiology of dysentery outbreaks.
- Genetic homology among outbreak strains points to specific causative agents.
