| Congresso Brasileiro de Microbiologia 2023 | Resumo: 1034-1 | ||||
Resumo:Gram-negative bacilli (GNB) bloodstream infections (BSI) are recurrent in immunocompromised patients. When GNB carry genetic determinants of antimicrobial resistance, the resulting infections can be fatal, especially when developed in the hospital setting and treated inadequately. Patients with hematological malignancies (HM), many times undergoing hematopoietic stem cell transplantation (HSCT), have their immune system, epithelial barriers, and microbiota impaired, offering a favorable environment for the establishment of GNB-BSI. Therefore, elucidating the elements involved in GNB-BSI is extremely important for the medical assistance of immunocompromised patients.
This work is part of a major prospective cohort study of patients with HM and/or undergoing HSCT, admitted at the transplant unit of a tertiary care hospital at Rio de Janeiro – Brazil, observing their gastrointestinal tract colonization and GNB-BSI. For the present analysis, the main objective was to investigate the microbiological and epidemiological aspects of the GNB-BSI in the cohort from September 2020 to December 2021. Blood cultures with GNB growth were sent to our laboratory for species identification and carbapenemase production evaluation.
During the study period, 64 patients were followed up after presenting GNB-BSI. Overall, 44% were female and the median age was 51 years old. The most common underlying diseases were acute myeloid leukemia (33%), acute lymphoid leukemia (16%), non-Hodgkin’s lymphomas (16%) and multiple myeloma (16%). Among these patients, 45 received HSCT, 15 autologous (33%) and 30 allogeneic (67%). According to the HSCT phase, 14 patients had early onset of BSI and one late after autologous transplantation; after allogeneic transplantation, 20 had early onset of BSI and 10 late.
For these patients, 81 GNB-BSI were diagnosed, in which 72 were caused by one agent and nine were caused by more than one, comprising a total of 91 agents. The most frequent BSI causing agent were Klebsiella spp. (32%), followed by Escherichia coli (24%), Pseudomonas aeruginosa (10%), Stenotrophomonas maltophilia (6,6%) and Serratia marcescens (4,4%). In 7 events, Klebsiella spp. were associated with another agent, mainly E. coli. All carbapenemase-producers causing BSI (10) were Klebsiella spp., comprising 34% of all BSI caused by these genera. Two patients had more than one BSI caused by carbapenemase-producing K. pneumoniae. Our laboratorial collection recorded 71,4% of these pathogens, including 90% of the Klebsiella spp. We identified 22 Klebsiella pneumoniae (08 carrying blaKPC-2), 01 K. pneumoniae subp. similipneumoniae, 01 K. quasipneumoniae subp. quasipneumoniae (blaKPC-2), 01 K. variicola subp. variicola and 01 K. variicola subp. tropica.
Further investigation of Klebsiella spp. and E. coli genome sequences is needed to understand the multiple aspects of GNB-BSI in these patients. This is highlighted by the alarming percentage of carbapenem-producing strains among the Klebsiella spp. causing BSI in our study. Therefore, by evaluating the microbiological and clinical data of GNB-BSI in immunocompromised patients from Brazil, we hope to contribute to a greater understanding of these infections and to help future efforts in preventing unfavorable clinical outcomes. Palavras-chave: Bloodstream infections, Carbapenemase, Gram-negative baccili, Hematological malignancies, Klebsiella spp. Agência de fomento:CNPQ, FAPERJ | |||||