Pseudomonas aeruginosa acquisition on an intensive care unit: relationship between antibiotic selective pressure and
Alexandre Boyer1, Adélaïde Doussau, Rodolphe Thiébault
1Service de Réanimation Médicale, Hôpital Pellegrin-Tripode, place Amélie Raba Léon, 33076 Bordeaux Cedex, France. alexandre.boyer@chu-bordeaux.fr
Introduction:
The purpose of this study was to investigate the relationship among Pseudomonas aeruginosa acquisition on the intensive care unit (ICU), environmental contamination and antibiotic selective pressure against P. aeruginosa.
Methods:
An open, prospective cohort study was carried out in a 16-bed medical ICU where P. aeruginosa was endemic. Over a six-month period, all patients without P. aeruginosa on admission and with a length of stay >72 h were included. Throat, nasal, rectal, sputum and urine samples were taken on admission and at weekly intervals and screened for P. aeruginosa. All antibiotic treatments were recorded daily. Environmental analysis included weekly tap water specimen culture and the presence of other patients colonized with P. aeruginosa.
Results:
A total of 126 patients were included, comprising 1,345 patient-days. Antibiotics were given to 106 patients (antibiotic selective pressure for P. aeruginosa in 39). P. aeruginosa was acquired by 20 patients (16%) and was isolated from 164/536 environmental samples (31%). Two conditions were independently associated with P. aeruginosa acquisition by multivariate analysis: (i) patients receiving ≥3 days of antibiotic selective pressure together with at least one colonized patient on the same ward on the previous day (odds ratio (OR) = 10.3 ((% confidence interval (CI): 1.8 to 57.4); P = 0.01); and (ii) presence of an invasive device (OR = 7.7 (95% CI: 2.3 to 25.7); P = 0.001).
Conclusions:
Specific interaction between both patient colonization pressure and selective antibiotic pressure is the most relevant factor for P. aeruginosa acquisition on an ICU. This suggests that combined efforts are needed against both factors to decrease colonization with P. aeruginosa.
Insights
Pseudomonas aeruginosa acquisition in intensive care units (ICUs) is linked to antibiotic use and patient colonization. Combined strategies targeting both factors are crucial for reducing P. aeruginosa infections.
Area of Science:
- Infectious Diseases
- Critical Care Medicine
- Microbiology
Background:
- Pseudomonas aeruginosa is a significant pathogen in healthcare settings, particularly intensive care units (ICUs).
- Understanding the factors driving P. aeruginosa acquisition is crucial for infection control.
Purpose of the Study:
- To investigate the relationship between P. aeruginosa acquisition in ICUs, environmental contamination, and antibiotic selective pressure.
- To identify key risk factors for P. aeruginosa acquisition in a medical ICU.
Main Methods:
- A prospective cohort study was conducted in a 16-bed medical ICU over six months.
- Patients were screened for P. aeruginosa, and antibiotic treatments were recorded daily.
- Environmental samples were cultured weekly, and patient colonization was monitored.
Main Results:
- P. aeruginosa was acquired by 16% of patients, and isolated from 31% of environmental samples.
- Antibiotic selective pressure combined with patient colonization significantly increased acquisition risk (OR=10.3).
- Invasive device presence was also independently associated with P. aeruginosa acquisition (OR=7.7).
Conclusions:
- The interaction between patient colonization pressure and selective antibiotic pressure is the primary driver of P. aeruginosa acquisition in ICUs.
- Combined interventions targeting both colonization and antibiotic use are necessary to mitigate P. aeruginosa acquisition.
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