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Susceptibility of viridans streptococci of 27 antimicrobial agents
Abstract:
One hundred and eighty strains of viridans Streptococci (Str. mitis, Str. salivarius, Str. MG, Str. SBE, Str. bovis, Str. equinus and Str. uberis) were isolated from mouth and upper respiratory tract secretions of humans at random in different parts of Poland. These strains were tested for susceptibility to 27 antimicrobial agents. Analysis of results was performed with special reference to bacterial endocarditis, which is caused mostly by these microorganisms. At low minimal inhibitory concentrations, most effective antibiotics appeared amoxycillin, clindamycin, azidocillin, cephaloridine, ampicillin, erythromycin and penicillin G. Susceptibility to other penicillins and cephalosporins was much less pronounced. Small part of strains was highly susceptible to tetracyclines, whereas all other antimicrobial agents were practically ineffective.
Insights
This study analyzed 180 viridans Streptococci strains from Poland, finding amoxicillin, clindamycin, and penicillin G highly effective against these bacteria, which are common causes of bacterial endocarditis.
Area of Science:
- Microbiology
- Infectious Diseases
- Pharmacology
Background:
- Viridans Streptococci are significant human pathogens, frequently implicated in bacterial endocarditis.
- Understanding antimicrobial susceptibility is crucial for effective treatment of infections caused by these bacteria.
Purpose of the Study:
- To assess the antimicrobial susceptibility profile of viridans Streptococci strains isolated from human samples in Poland.
- To identify effective antibiotic options for treating bacterial endocarditis caused by these microorganisms.
Main Methods:
- Isolation and identification of 180 viridans Streptococci strains from human oral and respiratory secretions.
- Determination of minimal inhibitory concentrations (MICs) for 27 different antimicrobial agents.
- Analysis of susceptibility patterns with a focus on clinical relevance for bacterial endocarditis.
Main Results:
- Amoxicillin, clindamycin, azidocillin, cephaloridine, ampicillin, erythromycin, and penicillin G demonstrated high efficacy at low MICs.
- Other penicillins and cephalosporins showed less pronounced activity.
- A small proportion of strains were susceptible to tetracyclines; most other agents were ineffective.
Conclusions:
- Amoxicillin, clindamycin, and penicillin G are recommended as primary choices for treating viridans Streptococci infections, including bacterial endocarditis.
- Limited susceptibility to tetracyclines and ineffectiveness of other agents highlight the need for targeted antimicrobial therapy.