Co-colonization by multidrug-resistant bacteria in two Greek intensive care units

Area of Science:

• Infectious Diseases
• Critical Care Medicine
• Microbiology

Background:

• Intensive care units (ICUs) are high-risk environments for the emergence and spread of multidrug-resistant organisms (MDROs).
• Co-colonization by KPC-producing Klebsiella pneumoniae (KPC-Kp), vancomycin-resistant enterococci (VRE), and methicillin-resistant Staphylococcus aureus (MRSA) poses a significant threat to patient outcomes.

Purpose of the Study:

• To identify risk factors associated with co-colonization by KPC-Kp, VRE, and MRSA upon ICU admission and during the ICU stay.
• To investigate the relationship between colonization by different MDROs.

Main Methods:

• Prospective study involving rectal and nasal sampling of 481 patients admitted to two Greek ICUs.
• Weekly sampling during ICU stay, with microbial identification using standard methods and Vitek-2 technology.
• Confirmation of specific resistance genes (blaKPC, vanA/vanB, mecA) via PCR.

Main Results:

• Upon ICU admission, 12% were colonized by KPC-Kp, 13% by VRE, and 4% by MRSA.
• KPC-Kp colonization was an independent risk factor for VRE colonization (OR 2.7 on admission, OR 7.4 during stay).
• VRE colonization was a risk factor for KPC-Kp (OR 5.1 on admission) and MRSA (OR 3.5 on admission, OR 14.5 during stay) colonization.

Conclusions:

• Colonization by one MDRO can promote colonization by another, suggesting a potential synergistic effect.
• Co-morbidities, antibiotic administration, and prior KPC-Kp infection were associated with KPC-Kp and VRE co-colonization.
• Effective infection control strategies are crucial to prevent co-colonization and subsequent infections in ICUs.