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

Abstract

Our goal was to identify the risk factors for co-colonization by KPC-producing Klebsiella pneumoniae (KPC-Kp), vancomycin-resistant enterococci (VRE), and methicillin-resistant Staphylococcus aureus (MRSA) upon intensive care unit (ICU) admission and during stay. Rectal and nasal samples were taken from each patient upon admission at two Greek ICUs and each week afterwards, and were inoculated onto chromogenic agar. Representative colonies were characterized with standard methods and Vitek-2 technology. The presence of the bla KPC gene (K. pneumoniae isolates), vanA and vanB (Enterococcus faecium and E. faecalis isolates), and mecA (S. aureus isolates) was confirmed by polymerase chain reaction (PCR). Upon ICU admission, among 481 patients, 59 (12%), 63 (13%), and 20 (4%) were colonized by KPC-Kp, VRE, or MRSA, respectively. Simultaneous colonization by KPC-Kp and VRE upon admission (34 patients) was associated with the number of co-morbidities [adjusted odds ratio (aOR): 1.5; confidence interval (CI) 1.0-2.5], administered antibiotics (aOR: 1.7; CI 1.3-2.3), and prior KPC-Kp infection (aOR: 24.4; CI 1.5-396.0). Among patients with an ICU stay of more than 6 days, 181 (73%), 31 (13%), and 9 (4%) became KPC-Kp, VRE, or MRSA colonized during ICU stay, respectively. KPC-Kp colonization was an independent risk factor for VRE colonization upon admission (aOR: 2.7; CI 1.0-7.2) and during stay (aOR: 7.4; CI 2.0-27.4), whereas VRE colonization was a risk factor for KPC-Kp upon admission (aOR: 5.1; CI 1.9-13.9) and MRSA colonization upon admission (aOR: 3.5; CI 1.2-10.1) and during ICU stay (aOR: 14.5; CI 2.1-100.1). Colonization by a multidrug pathogen could promote colonization by another.

Epidemiology and infection control of carbapenem resistant Acinetobacter baumannii and Klebsiella pneumoniae at a German university hospital: a retrospective study of 5 years (2015–2019)

“…As reported before by others [ 32 ], we can confirm that co-colonization with other multidrug resistant bacteria such as Methicillin-resistant Staphylococcus aureus and Vancomycin-resistant enterococci occurs frequently. Therefore, potential co-colonization should be kept in mind when practical infection controls measures as cohorting are discussed.…”

Vaccination can drive an increase in frequencies of antibiotic resistance among nonvaccine serotypes ofStreptococcus pneumoniae

“…Additionally, observational studies have found an increased risk of cocolonization by resistant gastrointestinal bacteria when a patient is already colonized by bacteria resistant to different classes of antibiotics, possibly indicating that resistant bacterial strains are less likely to be competitively excluded by each other than by susceptible strains. Such a risk of cocolonization was found independently of other risk factors such as antibiotic usage and patient comorbidities (60,61). Finally, experimental results suggest that patients receiving fecal microbiota transplant of susceptible bacteria are less likely to be recolonized by resistant bacteria (62).…”

Prevalence and molecular characterization of Staphylococcus aureus from human stool samples

“…It has been shown that a stay in an extended care facility or nursing home can significantly increase the risk of intestinal colonization [ 36 ]; however, we were unable to assess nursing home stays in the present study. Studies have also reported length of stay [ 37 ], a recent history of antimicrobial usage [ 37 – 39 ], a history of MRSA infection [ 38 ], and dependence on healthcare workers to perform activities of daily living [ 37 ] all significantly increasing the risk of intestinal S. aureus carriage. While we were not able to assess activities of daily living in the medical record, we did not detect a significant association with LOS, antibiotic usage, or the history of MRSA infections and colonization in our population.…”