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[Pseudomonas aeruginosa and surgical intensive care units]
D Rousseaux1, P M Osterrieth, P Damas
1Laboratoire de Bactériologie, Centre hospitalier de l'Université de Liege, Belgique.
Abstract:
The prevalence of Pseudomonas aeruginosa in intensive care unit (ICU) is 19 per cent although its incidence in blood culture is only 3.5 per cent and remains the same even though the total prevalence of this bacterium increases. A review of the clinical results shows that this germ causes severe complications in only 3 per cent of patients. A study by epidemiological markers reveals the presence of 16 different IATS serotypes in the ICU, this distribution of the serotypes being similar to this observed in ambulatory patients. The serotype 12 of Ps. aeruginosa is multiresistant. In 1984, it represented 22 per cent of the isolated Ps. aeruginosa, its incidence decreases in 1985 and in 1986 (14.5%). Ps. aeruginosa seems weakly pathogenic for the surgical patients in the ICU. On the other hand, the incidence of Klebsiella pneumoniae, Serratia marcescens (014 imm. serotype resistant to tobramycin), Enterobacter aerogenes and Enterobacter cloacae increases in blood cultures proportionally to their total prevalence in ICU. These bacteria are probably responsible for hospital epidemics.
Insights
Pseudomonas aeruginosa is common in ICUs but rarely causes severe infections. Other bacteria like Klebsiella pneumoniae are increasing and likely cause hospital epidemics.
Area of Science:
- Medical Microbiology
- Infectious Diseases
- Intensive Care Medicine
Background:
- Pseudomonas aeruginosa is prevalent in intensive care units (ICUs), but its incidence in blood cultures remains low.
- Despite increasing prevalence, Pseudomonas aeruginosa causes severe complications in a small percentage of ICU patients.
Purpose of the Study:
- To investigate the prevalence, serotypes, and clinical significance of Pseudomonas aeruginosa in an ICU setting.
- To compare the epidemiology of Pseudomonas aeruginosa with other Gram-negative bacteria in ICUs.
Main Methods:
- Epidemiological marker studies to identify different serotypes of Pseudomonas aeruginosa.
- Analysis of clinical data and blood culture results from ICU patients.
- Tracking the prevalence and incidence of various bacteria over time (1984-1986).
Main Results:
- Pseudomonas aeruginosa showed a prevalence of 19% in the ICU, with only 3.5% in blood cultures.
- Sixteen IATS serotypes of Pseudomonas aeruginosa were identified, with similar distribution to ambulatory patients.
- Multiresistant serotype 12 of Pseudomonas aeruginosa decreased from 22% in 1984 to 14.5% in 1986.
- Klebsiella pneumoniae, Serratia marcescens, Enterobacter aerogenes, and Enterobacter cloacae showed increasing incidence in blood cultures, correlating with their prevalence.
- Serratia marcescens (014 imm. serotype) was noted to be resistant to tobramycin.
Conclusions:
- Pseudomonas aeruginosa appears to have low pathogenicity in surgical ICU patients.
- Increasing incidence of Klebsiella pneumoniae, Serratia marcescens, and Enterobacter species suggests their role in hospital epidemics.
- Surveillance of bacterial epidemiology in ICUs is crucial for understanding infection trends and potential outbreaks.