Genotipizacija sevov vrste Escherichia coli, ki izločajo betalaktamaze z razširjenim spektrom delovanja, izoliranih iz hemokultur in nadzornih kužnin

Gobec, Nika (author), Ambrožič Avguštin, Jerneja (mentor), Pirš, Mateja (co-mentor)

V naši raziskavi smo analizirali 132 ESBL-pozitivnih izolatov E. coli, vzorčenih pri 66 bolnikih iz Osrednjeslovenske regije in izoliranih na Inštitutu za mikrobiologijo in imunologijo Medicinske fakultete Univerze v Ljubljani. V raziskavo smo vključili izolate bolnikov, pri katerih je bila ESBL-pozitivna E. coli najprej osamljena iz nadzorne kužnine, kasneje pa iz krvi. Z metodo ERIC-PCR smo izolate uvrstili v 33 skupin z različnimi ERIC-profili. Z analizo filogenetskih skupin po Clermontu smo ugotovili, da se 78,8 % izolatov iz hemokultur in 75,8 % izolatov iz nadzornih kužnin uvršča v filogenetsko skupino B2. V 53 % primerov (35) je bil izolat iz nadzorne kužnine enak izolatu iz krvi, od teh pa je bilo 80,6 % E. coli ST131. Zanimalo nas je, kakšna je genotipska razlika med izolati, ki kolonizirajo črevesje in niso vir za bakteriemijo ali sepso, ter izolati, ki jih najdemo v črevesju in krvi. Za slednje izolate so statistično značilni: gen za aerobaktin (82,3 %), kapsularni gen kpsMTII (82,3 %), zapis za avtotransporter sat (84,2 %), genotoksin usp (69,4 %) ter zapisa za adhezine iha (69,4 %) in afa/dra (40,3 %). Na podlagi prisotnosti teh genov bi z genotipizacijo črevesnih izolatov lahko odkrili tiste, pri katerih je tveganje za razvoj težje potekajočih izvenčrevesnih okužb z ESBL-E. coli zaradi lastnosti samega bakterijskega izolata, večje.

• Language: Slovenian
• Keywords: Escherichia coli, betalaktamaze, ESBL, genotipizacija, nadzorna kužnina, hemokultura
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: BF - Biotechnical Faculty
• Place of publishing: Ljubljana
• Publisher: [N. Gobec]
• Year: 2022
• PID: 20.500.12556/RUL-141282
• UDC: 579.25:579.842.1/.2:577.2
• COBISS.SI-ID: 123286787
• Publication date in RUL: 28.09.2022

Secondary language

• Language: English
• Title: Genotype analysis of Extended-spectrum beta-lactamase-producing Escherichia coli strains isolated from bloodstream infections and surveillance samples

Abstract

In our study, we analyzed 132 isolates of ESBL-positive E. coli sampled from 66 patients form Central Slovenian region and isolated at the Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana. Patients isolates were included in the study if the first ESBL-positive E. coli was isolate from surveillance sample followed by a blood culture isolate at a later date. Using the ERIC-PCR method, we were able to distinguish 33 different ERIC profiles. At the same time, we found that 78,8 % of isolates from blood cultures and 75,8 % of isolates from surveillance samples belonged to phylogenetic group B2. 53 % of patients (35) had genetically the same isolate in surveillance samples and blood cultures, of which 80,6 % were E. coli ST131. We compared the genotypes of isolates in surveillance samples, which were not the cause of bacetiemia or sepsis with isolates from hemocultures. We found statistically significant presence of the aerobactin operon (82,3 %), the capsule gene kpsMTII (82,3 %), the autotransporter gene sat (74,2 %), the genotoxin gene usp (69,4 %) and the adhesin genes iha (69,4 %) and afa/dra (40,3 %) in the nonclonal isolates from bloodstream infections. The presence of these genes in rectal isolates could be used to predict a higher risk of developing serious extraintestinal ESBL-E. coli infections based on genetic characteristics of the colonizing isolate.

• Keywords: Escherichia coli, betalactamases, ESBL, genotyping, surveillance swab, hemoculture