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[Antibiotic resistance and serotypes of Streptococcus pneumoniae in Zurich (1984-1985)]
Abstract:
We have investigated the serotypes and sensitivity of 133 pneumococci against 11 antimicrobial agents in the agar dilution test. The strains had been isolated from clinical specimens sent to the Department of Medical Microbiology of the University of Zurich during 1984 and 1985. - Three strains (2.3%) had reduced sensitivity to penicillin G. 23 strains (17.3%) showed resistance or reduced susceptibility to tetracycline, one strain each (0.8%) to amoxycillin and cefaclor, and two strains each (1.5%) to erythromycin and sulfamethoxazole/trimethoprim. All pneumococcal strains investigated were susceptible to ceftazidime, ceftriaxone, chloramphenicol, vancomycin and ciprofloxacin. In view of this situation, routine testing of all clinically significant pneumococci is to be recommended. However, in the agar diffusion test the use of a penicillin G disk is unreliable and may give results with false sensitivity. Therefore, the susceptibility test should be performed with a disk containing oxacillin. - The prevalent capsular serotypes were - in descending order - types 3, 6, 23, 19, 14, 7, 8, 9, 1, and 17. 90.2% of the isolated pneumococci belonged to serotypes which are contained in the new vaccine "Pneumovax-23".
Insights
This study analyzed pneumococcal strains, finding resistance to tetracycline and reduced sensitivity to penicillin. Most strains were susceptible to newer antibiotics, and 90.2% matched serotypes in the Pneumovax-23 vaccine.
Area of Science:
- Medical Microbiology
- Bacteriology
- Antimicrobial Resistance
Context:
- Pneumococcal infections pose a significant public health challenge.
- Monitoring antimicrobial susceptibility patterns is crucial for effective treatment.
- The study examined pneumococcal isolates from clinical specimens collected between 1984-1985.
Purpose:
- To determine the serotypes and antimicrobial sensitivity of pneumococcal strains.
- To evaluate the efficacy of various antimicrobial agents against these isolates.
- To inform clinical recommendations for pneumococcal infection management.
Summary:
- 133 pneumococcal strains were tested against 11 antimicrobial agents using agar dilution.
- Reduced sensitivity was observed for penicillin G (2.3%) and tetracycline (17.3%).
- All strains remained susceptible to ceftazidime, ceftriaxone, chloramphenicol, vancomycin, and ciprofloxacin.
- Prevalent serotypes included types 3, 6, 23, 19, and 14, with 90.2% covered by Pneumovax-23.
- Agar diffusion testing with penicillin G disks was found unreliable; oxacillin disks are recommended.
Impact:
- Highlights the emergence of antimicrobial resistance in pneumococci.
- Supports the routine antimicrobial susceptibility testing of clinically significant pneumococci.
- Identifies the serotype coverage of the Pneumovax-23 vaccine among circulating strains.
- Provides data to guide empirical antibiotic therapy and vaccine strategies.