Related Experiment Video
Updated: Jul 31, 2026
Nanomechanics of Drug-target Interactions and Antibacterial Resistance Detection
Published on: October 25, 2013
The role of "colonization pressure" in the spread of vancomycin-resistant enterococci: an important infection control
M J Bonten1, S Slaughter, A W Ambergen
1Department of Internal Medicine, University Hospital Maastricht, The Netherlands.
Objective:
The spread of nosocomial multiresistant microorganisms is affected by compliance with infection control measures and antibiotic use. We hypothesized that "colonization pressure" (ie, the proportion of other patients colonized) also is an important variable. We studied the effect of colonization pressure, compliance with infection control measures, antibiotic use, and other previously identified risk factors on acquisition of colonization with vancomycin-resistant enterococci (VRE).
Methods:
Rectal colonization was studied daily for 19 weeks in 181 consecutive patients who were admitted to a single medical intensive care unit. A statistical model was created using a Cox proportional hazards regression model including length of stay in the medical intensive care unit until acquisition of VRE, colonization pressure, personnel compliance with infection control measures (hand washing and glove use), APACHE (Acute Physiology and Chronic Health Evaluation) 11 scores, and the proportion of days that a patient received vancomycin or third-generation cephalosporins, sucralfate, and enteral feeding.
Results:
With survival until colonization with VRE as the end point, colonization pressure was the most important variable affecting acquisition of VRE (hazard ratio [HR], 1.032; 95% confidence interval [C1], 1.012-1.052; P=.002). In addition, enteral feeding was associated with acquisition of VRE (HR, 1.009; 95% CI, 1.000-1.017; P=.05), and there was a trend toward association of third-generation cephalosporin use with acquisition (HR, 1.007; 95% CI, 0.999-1.015; P=.11). The effects of enteral feeding and third-generation cephalosporin use were more important when colonization pressure was less than 50%. Once colonization pressure was 50% or higher, these other variables hardly affected acquisition of VRE.
Conclusions:
Acquisition of VRE was affected by colonization pressure, the use of antibiotics, and the use of enteral feeding. However, once colonization pressure was high, it became the major variable affecting acquisition of VRE.
Insights
Colonization pressure, the proportion of patients carrying vancomycin-resistant enterococci (VRE), is the primary driver of VRE acquisition in ICUs. High colonization pressure significantly outweighs other risk factors like antibiotic use and enteral feeding.
Area of Science:
- Infectious Diseases
- Critical Care Medicine
- Microbiology
Background:
- Nosocomial infections, particularly those caused by multiresistant microorganisms like vancomycin-resistant enterococci (VRE), pose a significant threat in healthcare settings.
- Compliance with infection control measures and judicious antibiotic use are known factors influencing VRE spread.
- The role of 'colonization pressure,' defined as the proportion of other patients colonized, as a key variable in VRE acquisition remained to be fully elucidated.
Purpose of the Study:
- To investigate the impact of colonization pressure on the acquisition of vancomycin-resistant enterococci (VRE) in a medical intensive care unit.
- To determine the relative importance of colonization pressure compared to other risk factors, including infection control compliance and antibiotic use, in VRE acquisition.
Main Methods:
- A prospective study involving daily rectal colonization surveillance for 19 weeks in 181 consecutive patients admitted to a medical intensive care unit.
- Utilized a Cox proportional hazards regression model to analyze the time to VRE acquisition, incorporating variables such as length of stay, colonization pressure, infection control compliance (hand hygiene, glove use), APACHE II scores, and specific medication/feeding exposures (vancomycin, third-generation cephalosporins, sucralfate, enteral feeding).
Main Results:
- Colonization pressure emerged as the most significant factor associated with VRE acquisition (Hazard Ratio [HR] = 1.032, P = .002).
- Enteral feeding also showed a significant association with VRE acquisition (HR = 1.009, P = .05).
- A trend towards association was observed for third-generation cephalosporin use (HR = 1.007, P = .11). The impact of enteral feeding and cephalosporin use was more pronounced when colonization pressure was below 50%.
Conclusions:
- Colonization pressure is a critical determinant of vancomycin-resistant enterococci acquisition in intensive care units.
- While antibiotic use and enteral feeding contribute to VRE acquisition, their influence diminishes significantly when colonization pressure is high (≥50%).
- Strategies to control VRE spread must prioritize reducing overall colonization pressure within the healthcare environment.
Related Concept Videos
00:57Antibiotic Selection
01:26Factors Affecting the Risk of Infection
The integrity and count of the white blood cells help the body resist pathogens and fight infection. When impaired, it reduces the body's resistance to pathogens. The acidic pH levels of the gastrointestinal, genitourinary tracts, and skin create...
01:30Development of Antibiotic Resistance
01:25Colonisation of Pathogens
01:25Mechanism of Antibiotic Resistance in MRSA
01:25Clinical Significance of Antibiotic Resistance