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[Characteristics of hospital strains of Pseudomonas aeruginosa]
Abstract:
A total of 745 P. aeruginosa strains from patients with purulent inflammatory processes, 216 strains from the environment of a surgical hospital and 35 strains from carriers were studied with respect to 30 cultural and biochemical signs of P. aeruginosa. 19.8% of the strains were found to form no pigment, and in 14.8% of the strains delayed pigment formation was observed (on days 3-10). The most stable signs were motility (99.6%), growth in Simmons citrate agar (97.6%), growth at 42 degrees C (97.4%), arginine decarboxylase activity (96.8%). In 77.0% of the strains glucose assimilation in Hiss liquid medium, in 85.6% glucose oxidation in the OF test, in 90.8% the formation of urease and in 93.2% the formation of gelatinase were observed. Among the strains isolated from the environment, P. aeruginosa variants, atypical with respect to their main differentiating signs, were isolated significantly more frequently.
Insights
This study analyzed 745 Pseudomonas aeruginosa strains, revealing variations in pigment formation and identifying stable biochemical markers like motility and growth at 42°C. Environmental strains showed more atypical characteristics.
Area of Science:
- Microbiology
- Clinical Microbiology
Background:
- Pseudomonas aeruginosa is an opportunistic pathogen frequently isolated from clinical and environmental sources.
- Understanding the phenotypic diversity of P. aeruginosa is crucial for accurate identification and epidemiological studies.
Purpose of the Study:
- To characterize the cultural and biochemical properties of a large collection of P. aeruginosa strains.
- To identify stable and variable phenotypic markers within P. aeruginosa populations.
- To investigate potential differences in P. aeruginosa strains isolated from clinical, carrier, and environmental settings.
Main Methods:
- Phenotypic characterization of 745 P. aeruginosa strains using 30 cultural and biochemical tests.
- Analysis of strains from patients with purulent inflammatory processes, surgical hospital environments, and carriers.
- Comparison of phenotypic profiles between different isolate sources.
Main Results:
- Significant variations in pigment formation were observed, with 19.8% forming no pigment and 14.8% showing delayed formation.
- Highly stable characteristics included motility (99.6%), growth on Simmons citrate agar (97.6%), growth at 42°C (97.4%), and arginine decarboxylase activity (96.8%).
- Atypical P. aeruginosa variants were more frequently isolated from the hospital environment compared to clinical or carrier sources.
Conclusions:
- P. aeruginosa exhibits considerable phenotypic variability, particularly in pigment production.
- Certain biochemical markers demonstrate high stability and can be reliably used for identification.
- Environmental P. aeruginosa isolates may possess distinct characteristics, necessitating careful consideration in diagnostic and surveillance efforts.