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[Hospital strains of Salmonella serotype typhimurium with particular biological properties]
Abstract:
93 cultures of Salmonella typhimurium (STm) were isolated from the infants (under one year old) admitted into a pediatrics ward. All the cultures had only flagellation antigens in phase I, a common sensitivity spectrum to antibiotics and the same sensitivity to the sets of bacteriophages for typing of this serotype. Of these, 10 strains were negative H2S and 6 immobile. Using as carrier a strain of E. coli, K12Nxr, an experimental transfer of multiple resistance to the antibiotics obtained from strains of Salmonella, agona serotype (with special resistance markers) to STm strains was made. The transfer was equally possible to monophasic and diphasic strains of STm. In the transfer to the diphasic strains, the modification of the phage type was noticed. The results suggest the possibility of the in vivo transfer of R plasmids from the agona serum to the typhimurium serum of Salmonella.
Insights
Researchers studied Salmonella typhimurium (STm) in infants, finding that antibiotic resistance plasmids can transfer between STm strains. This transfer, observed in laboratory experiments, suggests potential for in vivo spread of antibiotic resistance in Salmonella serotypes.
Area of Science:
- Microbiology
- Infectious Diseases
- Genetics
Background:
- Salmonella typhimurium (STm) is a significant pathogen, particularly in vulnerable populations like infants.
- Understanding the mechanisms of antibiotic resistance spread is crucial for public health.
- Previous studies have indicated the potential for plasmid-mediated resistance transfer in bacteria.
Purpose of the Study:
- To investigate the potential for horizontal gene transfer of antibiotic resistance plasmids between Salmonella serotypes.
- To examine the transferability of antibiotic resistance markers from Salmonella agona to Salmonella typhimurium strains.
- To assess the impact of plasmid transfer on the phage type of recipient Salmonella typhimurium strains.
Main Methods:
- Isolation and characterization of 93 Salmonella typhimurium (STm) cultures from infants.
- Experimental transfer of antibiotic resistance plasmids using an E. coli K12Nxr strain as a carrier.
- Phage typing of recipient STm strains to assess modifications post-plasmid transfer.
Main Results:
- Antibiotic resistance plasmids were successfully transferred from Salmonella agona to STm strains, including both monophasic and diphasic variants.
- The transfer of resistance markers was confirmed using specific resistance markers.
- A modification in the phage type of diphasic STm strains was observed following plasmid transfer.
Conclusions:
- The study demonstrates the feasibility of transferring R plasmids between Salmonella serotypes.
- Results suggest that in vivo transfer of R plasmids from Salmonella agona to Salmonella typhimurium is possible.
- This highlights a potential mechanism for the dissemination of antibiotic resistance within Salmonella populations.