DOI: 10.3390/antibiotics13050448 ISSN: 2079-6382

Colonization by Extended-Spectrum β-Lactamase-Producing Enterobacterales and Bacteremia in Hematopoietic Stem Cell Transplant Recipients

Luiza Arcas Gonçalves, Beatriz Barbosa Anjos, Bruno Melo Tavares, Ana Paula Marchi, Marina Farrel Côrtes, Hermes Ryoiti Higashino, Bruna del Guerra de Carvalho Moraes, José Victor Bortolotto Bampi, Liliane Dantas Pinheiro, Fernanda de Souza Spadao, Vanderson Rocha, Thais Guimarães, Silvia Figueiredo Costa

Background: Assessing the risk of multidrug-resistant colonization and infections is pivotal for optimizing empirical therapy in hematopoietic stem cell transplants (HSCTs). Limited data exist on extended-spectrum β-lactamase-producing Enterobacterales (ESBL-E) colonization in this population. This study aimed to assess whether ESBL-E colonization constitutes a risk factor for ESBL-E bloodstream infection (BSI) and to evaluate ESBL-E colonization in HSCT recipients. Methods: A retrospective analysis of ESBL-E colonization and BSI in HSCT patients was conducted from August 2019 to June 2022. Weekly swabs were collected and cultured on chromogenic selective media, with PCR identifying the β-lactamase genes. Pulsed-field gel electrophoresis (PFGE) and whole-genome sequencing (WGS) assessed the colonizing strains’ similarities. Results: Of 222 evaluated HSCT patients, 59.45% were colonized by ESBL-E, with 48.4% at admission. The predominant β-lactamase genes were blaTEM (52%) and blaSHV (20%). PFGE analysis did not reveal predominant clusters in 26 E. coli and 15 K. pneumoniae strains. WGS identified ST16 and ST11 as the predominant sequence types among K. pneumoniae. Thirty-three patients developed thirty-five Enterobacterales-BSIs, with nine being third-generation cephalosporin-resistant. No association was found between ESBL-E colonization and ESBL-BSI (p = 0.087). Conclusions: Although the patients presented a high colonization rate of ESBL-E upon admission, no association between colonization and infection were found. Thus, it seems that ESBL screening is not a useful strategy to assess risk factors and guide therapy for ESBL-BSI in HSCT-patients.

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