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Epithelial Cell Infection Analyses with Shigella
Published on: February 9, 2024
Molecular mechanism of multi-drug resistance in Shigella isolates from rural China
1Department of Epidemiology, College of Public Health, Zhengzou University, Henan, China.
Abstract:
Diarrhoeal diseases and enteric infections are major causes of morbidity and mortality in the developing countries. Shigellosis was sixth in the rank of death caused by infectious disease in China. Present study assess the patterns of antimicrobial susceptibility and mutations in marA genes of Shigella isolates and its association. One hundred isolates of Shigella spp were tested to evaluate the antimicrobial susceptibility and mutation of marA through PCR-SSCP. The antimicrobial resistance profiles were: Amoxicilline-clavum (85%), Nalidixic acid (100%), Piperacilline (100%), Ciprofloxacin (25%) and Polymixin B (1.1%). S. flexneri isolates were more resistant than those ofS. sonnei to Amoxicilline-clavum (96.6% versus 0.0%, P<0.001) and Ciprofloxacin (27.3% versus 8.3%, P=0.141). S. flexneri isolates were more resistant than those of S. sonnei to three or more antimicrobial agents (96.6% versus 8.3%, P<0.001). Overall mutation rate in marA was 19%. Nucleotide sequencing showed mutations in three positionsÿcodon 6 ( Delation of C), 319 (Ala Gly) and 374 (Addition of C). The mutation of marA may play a minor role and other mechanisms may contribute to the drug resistance of Shigella spp.
Insights
Shigella infections show high resistance to common antibiotics like amoxicillin-clavulanate and nalidixic acid. While mutations in the marA gene were observed, they appear to play a minor role in the overall antimicrobial resistance of Shigella.
Area of Science:
- Microbiology
- Infectious Diseases
- Genetics
Background:
- Diarrhoeal diseases and enteric infections are significant causes of illness and death in developing nations.
- Shigellosis ranks as a major infectious disease contributor to mortality in China.
Purpose of the Study:
- To investigate antimicrobial susceptibility patterns in Shigella isolates.
- To identify mutations in the marA gene and assess their association with drug resistance in Shigella.
Main Methods:
- Antimicrobial susceptibility testing was performed on 100 Shigella isolates.
- Polymerase Chain Reaction-Single Strand Conformation Polymorphism (PCR-SSCP) was used to detect marA gene mutations.
Main Results:
- High resistance rates were observed for amoxicillin-clavulanate (85%), nalidixic acid (100%), and piperacillin (100%).
- Shigella flexneri exhibited greater resistance to amoxicillin-clavulanate and ciprofloxacin compared to Shigella sonnei.
- A 19% mutation rate was found in the marA gene, with specific mutations identified at codons 6, 319, and 374.
Conclusions:
- Shigella isolates display considerable antimicrobial resistance, particularly to amoxicillin-clavulanate and nalidixic acid.
- Mutations in the marA gene may contribute to drug resistance in Shigella, but likely play a secondary role to other resistance mechanisms.
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