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Epidemic Shiga bacillus dysentery in Central Africa
Abstract:
An outbreak of dysentery began late in 1979 in Central Africa and spread to involve a major portion of Zaire as well as Rwanda and Burundi. We traveled to a mission hospital in northeast Zaire during the epidemic and isolated Shigella dysenteriae, type 1, from most of the patients studied. All isolates were resistant to ampicillin, tetracycline, chloramphenicol, sulfathiazole, and streptomycin but sensitive to trimethoprim-sulfamethoxazole. Antimicrobial resistance was transferable to Escherichia coli, and at least three plasmids were identified in the donor Shigella isolates by using agarose gel electrophoresis. One was coded for ampicillin, tetracycline, and chloramphenicol resistance while a second conferred resistance to ampicillin and chloramphenicol but not tetracycline. A third large plasmid of approximately 120 megadaltons could not be transferred to E. coli recipients. All S. dysenteriae isolates yielded identical kinetic growth curves when analyzed on the Abbot MS-2 Research System. This is the most extensive outbreak of dysentery caused by S. dysenteriae reported since the Central American epidemic of 1969, and the first epidemic caused by a strain resistant to ampicillin.
Insights
A major dysentery outbreak in Central Africa involved Shigella dysenteriae type 1, resistant to multiple antibiotics. This strain
Area of Science:
- Microbiology
- Epidemiology
- Infectious Diseases
Background:
- An extensive outbreak of dysentery occurred in Central Africa starting in 1979.
- The epidemic affected Zaire, Rwanda, and Burundi, with Shigella dysenteriae type 1 identified as the causative agent.
Purpose of the Study:
- To investigate the characteristics of Shigella dysenteriae type 1 during a major epidemic in northeast Zaire.
- To determine antimicrobial resistance patterns and genetic basis of resistance in the outbreak strain.
Main Methods:
- Isolation and identification of Shigella dysenteriae type 1 from patients.
- Antimicrobial susceptibility testing.
- Plasmid analysis using agarose gel electrophoresis.
- Transferable antimicrobial resistance studies using Escherichia coli recipients.
- Kinetic growth curve analysis using the Abbot MS-2 Research System.
Main Results:
- Shigella dysenteriae type 1 was isolated from most patients studied.
- All isolates exhibited resistance to ampicillin, tetracycline, chloramphenicol, sulfathiazole, and streptomycin.
- Isolates were sensitive to trimethoprim-sulfamethoxazole.
- Antimicrobial resistance was transferable to Escherichia coli.
- Three plasmids were identified, with two conferring resistance to multiple antibiotics.
Conclusions:
- This outbreak represents the most extensive epidemic of dysentery caused by Shigella dysenteriae since 1969.
- The causative strain was resistant to ampicillin, a first for reported epidemics.
- Trimethoprim-sulfamethoxazole emerged as a potential treatment option.