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Isolation and study of fosfomycin-resistant mutants of group A and B streptococci
L E Ravdonikas1, K B Grabovskaya, A A Totolian
1Institute of Experimental Medicine, Academy of Science of USSR, Leningrad.
Abstract:
Eighty-nine fosfomycin-resistant mutants of group A and B streptococci were isolated. The mutants differed essentially from the parent strains in cell-wall characteristics, such as morphology of cocci and chains, sensitivity to detergents and hydrophobic properties. At the same time, the recipient activity of the investigated mutants was not changed. It is supposed that resistance of mutants to fosfomycin is connected with a transport block of glycerol 3-phosphate--important lipoteichoic acid (LTA) structural component. Fosr mutants can be useful for experimental examination of Beachey's hypothesis about the importance of LTA or its complex with the M protein for adhesion.
Insights
Fosfomycin resistance in streptococci mutants is linked to cell wall changes affecting glycerol 3-phosphate transport. These resistant strains may help study bacterial adhesion mechanisms.
Area of Science:
- Microbiology
- Bacterial Genetics
- Cell Wall Biology
Background:
- Streptococci are significant human pathogens.
- Fosfomycin is an antibiotic used to treat infections.
- Understanding antibiotic resistance mechanisms is crucial for public health.
Purpose of the Study:
- To isolate and characterize fosfomycin-resistant mutants of group A and B streptococci.
- To investigate the cell wall alterations associated with fosfomycin resistance.
- To explore the potential role of lipoteichoic acid (LTA) transport in resistance.
Main Methods:
- Isolation of 89 fosfomycin-resistant streptococcal mutants.
- Analysis of cell-wall characteristics including morphology, detergent sensitivity, and hydrophobicity.
- Assessment of recipient activity in the isolated mutants.
Main Results:
- Mutants exhibited significant differences in cell-wall characteristics compared to parent strains.
- Key changes included altered cocci and chain morphology, modified detergent sensitivity, and altered hydrophobic properties.
- Recipient activity remained unchanged in the resistant mutants.
Conclusions:
- Fosfomycin resistance in these streptococci is likely due to a transport block of glycerol 3-phosphate, a key component of LTA.
- The observed cell wall modifications highlight the intricate relationship between antibiotic resistance and bacterial surface properties.
- These fosfomycin-resistant mutants (Fosr) offer a valuable tool for investigating Beachey's hypothesis on the role of LTA and M protein in bacterial adhesion.