AUTHOR=Migliorini Letícia Busato , Leaden Laura , de Sales Romário Oliveira , Correa Nathalia Pellegrini , Marins Maryana Mara , Koga Paula Célia Mariko , Toniolo Alexandra do Rosario , de Menezes Fernando Gatti , Martino Marines Dalla Valle , Mingorance Jesús , Severino Patricia 

TITLE=The Gastrointestinal Load of Carbapenem-Resistant Enterobacteriacea Is Associated With the Transition From Colonization to Infection by Klebsiella pneumoniae Isolates Harboring the blaKPC Gene

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=12

YEAR=2022

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2022.928578

DOI=10.3389/fcimb.2022.928578

ISSN=2235-2988

ABSTRACT=<sec><title>Background</title><p>Healthcare-associated infections by carbapenem-resistant <italic>Klebsiella pneumoniae</italic> are difficult to control. Virulence and antibiotic resistance genes contribute to infection, but the mechanisms associated with the transition from colonization to infection remain unclear.</p></sec><sec><title>Objective</title><p>We investigated the transition from carriage to infection by <italic>K. pneumoniae</italic> isolates carrying the <italic>K. pneumoniae</italic> carbapenemase–encoding gene <italic>bla</italic><sub>KPC</sub> (KpKPC).</p></sec><sec><title>Methods</title><p>KpKPC isolates detected within a 10-year period in a single tertiary-care hospital were characterized by pulsed-field gel electrophoresis (PFGE), multilocus sequencing typing, capsular lipopolysaccharide and polysaccharide typing, antimicrobial susceptibility profiles, and the presence of virulence genes. The gastrointestinal load of carbapenem-resistant Enterobacteriaceae and of <italic>bla</italic><sub>KPC</sub>-carrying bacteria was estimated by relative quantification in rectal swabs. Results were evaluated as contributors to the progression from carriage to infection.</p></sec><sec><title>Results</title><p>No PGFE type; ST-, K-, or O-serotypes; antimicrobial susceptibility profiles; or the presence of virulence markers, such yersiniabactin and colibactin, were associated with carriage or infection, with ST437 and ST11 being the most prevalent clones. Admission to intensive and semi-intensive care units was a risk factor for the development of infections (OR 2.79, 95% CI 1.375 to 5.687, <italic>P</italic>=0.005), but higher intestinal loads of carbapenem-resistant Enterobacteriaceae or of <italic>bla</italic><sub>KPC</sub>-carrying bacteria were the only factors associated with the transition from colonization to infection in this cohort (OR 8.601, 95% CI 2.44 to 30.352, <italic>P</italic>&lt;0.001).</p></sec><sec><title>Conclusion</title><p>The presence of resistance and virulence mechanisms were not associated with progression from colonization to infection, while intestinal colonization by carbapenem-resistant Enterobacteriacea and, more specifically, the load of gastrointestinal carriage emerged as an important determinant of infection.</p></sec>