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

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 ß-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 ß-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 ß-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.

MRSA outbreak in a Neonatal Intensive Care Unit in a developed country: importance of rapid detection of reservoirs and implementation of intervention measures

ABSTRACT We described a MRSA bloodstream infection outbreak that was rapidly identified and controlled in a Neonatal Intensive Care Unit after implementation of a bundle of measures, including PCR-screening and HCW decolonization. We found 35% of healthcare workers(HCW) colonized with S. aureus by PCR, one of them that presented skin lesion positive for MSSA (same clone and spa type than two patients). Our findings raise the hypothesis that the outbreak could be related to HCW colonization.