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[The antimicrobial susceptibilities and serotypes of Pseudomonas aeruginosa isolated from sputum]
Y Fujiue1, M Kuwabara, K Muroki
1Department of Pathology, Hiroshima Prefectural Hiroshima Hospital.
Abstract:
During the period of January 1992 and August 1995, 75 strains of Pseudomonas aeruginosa were isolated from sputum at the Hiroshima Prefectural Hiroshima Hospital. The antimicrobial susceptibilities and serotypes of those strains were investigated. The results are summarized as follows: 1. The analyses of antimicrobial susceptibilities revealed that meropenem (MEPM) was the most active among the carbapenems tested against those P. aeruginosa strains with MIC of < or = 6.25 micrograms/ml. All of the strains were thus found to be susceptible to MEPM, while 9 strains out of 75 (12%) were resistant to imipenem showing cross-resistance to biapenem. 2. The activities of the beta-lactams other than carbapenems were found to be the order of cefozopran > or = ceftazidime > aztreonam > piperacillin with MIC50 and MIC90 ranging of 3.13-6.25 micrograms/ml and 25- > or = 100 micrograms/ml, respectively. 3. Among aminoglycosides tested, 3 strains (4.0%) of the strains showed resistance to amikacin, however none of them were resistant to tobramycin. 4. Distribution of serotypes among the strains was; type G 22.7%, type M 21.3%, type A 16.0%, type B 13.3% and type E 8.0%. Strains of types M and E showed multiple resistance to beta-lactams except carbapenems. As documented in this study, the frequency of isolation of beta-lactam-resistant P. aeruginosa (including carbapenem-resistant) is steadily increasing. Continuous surveillance of antimicrobial susceptibility among clinically isolated P. aeruginosa seems to be necessary.
Insights
This study found meropenem highly effective against Pseudomonas aeruginosa strains, with increasing resistance to other beta-lactams. Continuous antimicrobial susceptibility surveillance is crucial for managing these resistant bacterial infections.
Area of Science:
- Medical Microbiology
- Infectious Diseases
- Antimicrobial Resistance
Background:
- Pseudomonas aeruginosa is a significant opportunistic pathogen.
- Rising antimicrobial resistance in P. aeruginosa poses a clinical challenge.
Purpose of the Study:
- To investigate the antimicrobial susceptibilities and serotypes of P. aeruginosa strains isolated from sputum.
- To assess the prevalence of resistance to carbapenems and other beta-lactams.
Main Methods:
- Isolation and antimicrobial susceptibility testing of 75 P. aeruginosa strains.
- Serotyping of the isolated strains.
- Evaluation of meropenem, imipenem, biapenem, other beta-lactams, and aminoglycosides.
Main Results:
- Meropenem showed high activity (MIC ≤ 6.25 µg/ml) against all strains.
- 12% of strains were resistant to imipenem, with cross-resistance to biapenem.
- Resistance to amikacin was observed in 4.0% of strains, but none were resistant to tobramycin.
- Serotypes M and E exhibited multiple resistances to beta-lactams (excluding carbapenems).
Conclusions:
- The frequency of beta-lactam-resistant P. aeruginosa, including carbapenem-resistant strains, is increasing.
- Continuous surveillance of antimicrobial susceptibility is necessary for effective clinical management.
- Meropenem remains a highly effective agent against the studied P. aeruginosa isolates.