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Antibiotic Resistance Patterns of Bacteria Involved in Colonization and/or Infection of Patients in Intensive Care
Alexandru Duhaniuc1,2, Cristina Mihaela Sima1,3, Georgiana Buruiană1,3
1Department of Preventive Medicine and Interdisciplinarity-Microbiology, Grigore T. Popa University of Medicine and Pharmacy, 700115 Iasi, Romania.
Background/Objectives:
Healthcare-associated infections caused by multidrug-resistant (MDR) bacteria pose a significant and growing public health challenge, particularly in high-risk settings such as Intensive Care Units (ICUs). Colonization is often asymptomatic but can precede infection and contribute to hospital outbreaks, making early detection critical for infection control and containment. The aim of the study is to evaluate the antibiotic susceptibility patterns of MDR bacteria involved in colonization and/or infection among patients admitted to the ICU at a tertiary care hospital in Northeastern Romania and to investigate the relationship between MDR bacterial colonization and subsequent infection.
Methods:
A total of 118 patients from ICU were included in this study and a total of 609 bacterial strains were isolated, involved in both colonization and infection, with multiple isolates per patient included if obtained from different sites or time points.
Results:
A predominance of Gram-negative bacilli was found to be involved in both colonization and infection in the ICU, with Acinetobacter baumannii (n = 146; 26.64%), Klebsiella pneumoniae (n = 146; 26.64%), Escherichia coli (n = 60; 10.95%), and Pseudomonas aeruginosa (n = 56; 10.22%) as the main bacteria involved in colonization, and A. baumannii (n = 23; 37.7%), K. pneumoniae (n = 19; 31.1%), and P. aeruginosa (n = 15; 24.6%) as the main bacteria involved in infections. The study revealed a high diversity of antibiotypes among K. pneumoniae (43 distinct antibiotypes), E. coli (35 distinct antibiotypes) and P. aeruginosa (27 distinct antibiotypes). In contrast, only 6 antibiotypes were identified for A. baumannii, with most strains belonging to a single dominant antibiotype. For K. pneumoniae, E. coli and A. baumannii, infections mainly involved the same antibiotype as that found in colonization, while infections with P. aeruginosa were often linked to different antibiotypes than those involved in colonization.
Conclusions:
This study demonstrates a high colonization-to-infection link among ICU patients in a Northeastern Romanian tertiary care hospital, and these findings underscore the importance of systematic colonization screening to identify patients at high risk in ICU settings.
Insights
Multidrug-resistant bacteria colonization in Intensive Care Units (ICUs) frequently leads to infection. Systematic screening for colonization is crucial for identifying high-risk patients and improving infection control in ICUs.
Area of Science:
- Medical Microbiology
- Infectious Diseases
- Public Health
Background:
- Healthcare-associated infections (HAIs) caused by multidrug-resistant (MDR) bacteria are a significant global health threat.
- Intensive Care Units (ICUs) are high-risk settings where MDR bacterial colonization can precede infection and drive outbreaks.
- Early detection of colonization is vital for effective infection control and containment strategies.
Purpose of the Study:
- To evaluate antibiotic susceptibility patterns of MDR bacteria causing colonization and/or infection in ICU patients.
- To investigate the link between MDR bacterial colonization and subsequent infection development.
- To assess the prevalence of specific MDR bacterial species and their antibiotypes in an ICU setting.
Main Methods:
- A cohort of 118 patients admitted to an ICU in Northeastern Romania was studied.
- A total of 609 bacterial strains were isolated from various sites and time points.
- Antibiotic susceptibility testing and antibiotype diversity analysis were performed on isolated strains.
Main Results:
- Gram-negative bacilli predominated, with *Acinetobacter baumannii*, *Klebsiella pneumoniae*, *Escherichia coli*, and *Pseudomonas aeruginosa* being the most common MDR bacteria.
- High diversity of antibiotypes was observed for *K. pneumoniae*, *E. coli*, and *P. aeruginosa*, while *A. baumannii* showed a dominant antibiotype.
- A strong colonization-to-infection link was observed for *K. pneumoniae*, *E. coli*, and *A. baumannii*, with infections often involving the same antibiotype as colonization.
Conclusions:
- A significant colonization-to-infection pathway exists for MDR bacteria in ICU patients.
- Findings highlight the importance of systematic colonization screening in ICUs to identify at-risk individuals.
- Implementing targeted surveillance can enhance infection control measures against MDR bacteria in critical care settings.
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