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Antibiotic resistance among enterococci isolated from clinical specimens between 1953 and 1954
B A Atkinson1, A Abu-Al-Jaibat, D J LeBlanc
1Department of Medicine, University of Texas Health Science Center at San Antonio, 78284, USA.
Abstract:
Two hundred twenty group D streptococci isolated from 1953 to 1954 from patients in the Washington, D.C., area were characterized. All were susceptible to ampicillin, vancomycin, and gentamicin; none produced beta-lactamase activity. High-level resistance to streptomycin was expressed by 117 strains, and 2 strains were resistant to >8 microg of chloramphenicol per ml. Three isolates were resistant to both erythromycin and lincomycin, and DNA from these hybridized to an ermAM probe. Of 118 strains resistant to tetracycline and minocycline, genomic DNA from 63 was examined for homology to tet(M), tet(O), and tet(S). DNA from 20 strains hybridized to tet(M), DNA from 37 strains hybridized to tet(S), and DNA from none of the strains hybridized to tet(O).
Insights
This study characterized 220 group D streptococci from 1953-1954. Most strains showed resistance to streptomycin, while some exhibited resistance to tetracycline and chloramphenicol.
Area of Science:
- Microbiology
- Antimicrobial Resistance
Background:
- Group D streptococci are significant human pathogens.
- Understanding historical antibiotic resistance patterns is crucial for public health.
Purpose of the Study:
- To characterize the antimicrobial resistance profiles of group D streptococci from the mid-20th century.
- To identify specific resistance genes present in these historical isolates.
Main Methods:
- Phenotypic characterization of antibiotic susceptibility.
- Molecular analysis using DNA hybridization with specific resistance gene probes (ermAM, tet(M), tet(O), tet(S)).
Main Results:
- All isolates were susceptible to ampicillin, vancomycin, and gentamicin.
- High-level streptomycin resistance was common (117 strains).
- Tetracycline resistance was mediated by tet(M) (20 strains) and tet(S) (37 strains).
- Erythromycin and lincomycin resistance was linked to the ermAM gene.
Conclusions:
- Group D streptococci exhibited significant resistance to streptomycin and tetracycline in the 1950s.
- Specific resistance genes like tet(M), tet(S), and ermAM were present in these early isolates.
- This historical data provides a baseline for tracking the evolution of antimicrobial resistance.