Bloodstream infections in immunocompromised adult patients

• Hospital-acquired BSI were linked to multidrug-resistant (MDR) microorganisms. • Community cases were more often driven by Escherichia coli , from urinary source. • Risk factors for MDR: prolonged hospital stay, prior antibiotic use, surgery. • 30-Days mortality was higher among patients with recent COVID-19 infection. • These highlight the need for protocols for immunosuppressed patients at risk of BSI. Bloodstream infections (BSIs) are a major cause of morbidity and mortality in immunocompromised hosts, particularly those with malignancies, transplants, or autoimmune diseases. Epidemiologic surveillance is critical to optimize empirical antimicrobial therapy. Our aims were to describe the frequency, clinical and microbiological characteristics of BSIs in immunocompromised patients treated at two hospitals in Córdoba, Argentina. We conducted a retrospective study at two tertiary care centers in Córdoba, Argentina, including adult immunocompromised patients with microbiologically confirmed BSIs between January 2019 and December 2022. Underlying immunosuppression included malignancy, neutropenia, transplantation, or immunosuppressive therapy. Clinical data were analyzed over a 30-day period, and microbiological isolates were characterized. A total of 181 BSI episodes were included; 97 (53.6%) were hospital-acquired (HA-BSI) and 84 (46.4%) community-acquired (CA-BSI). Median age was 62 years (IQR 54.5–71.5), and 101 (55.8%) were male patients. Active malignancy was the most common immunosuppressive condition (n = 124, 68.5%). Primary bacteremia occurred in 51 cases (28.2%). Urinary (n = 34, 18.8%), intra-abdominal (n = 30, 16.6%), and catheter-related infections (n = 24, 13.3%) were the leading sources. Gram-negative bacilli (GNB) predominated (n = 150, 75.8%), with Escherichia coli (n = 71, 35.9%) and Klebsiella pneumoniae (n = 30, 15.2%) being the most frequent isolates. Multidrug-resistant organisms (MDRO) were identified in 67 (33.8%) episodes, more commonly in HA-BSI than CA-BSI (37 46.3% vs 15 21.4%, p = 0.001). The overall 30-day mortality rate was 24.8% (n = 45). This study demonstrated that, in this cohort of immunocompromised adults, BSIs were slightly more often hospital-acquired and associated with substantial mortality. One-third of the isolates were multidrug-resistant organisms (MDROs). Las infecciones del torrente sanguíneo (ITS) son causa importante de morbilidad y mortalidad en pacientes inmunocomprometidos, particularmente aquellos con neoplasias, trasplantes o enfermedades autoinmunitarias. Nuestros objetivos fueron describir la frecuencia y características clínicas y microbiológicas de las ITS en pacientes inmunocomprometidos atendidos en dos hospitales de Córdoba, Argentina. Llevamos a cabo un estudio retrospectivo en dos hospitales, incluyendo pacientes adultos inmunocomprometidos con ITS entre enero de 2019 y diciembre de 2022. Las causas de inmunosupresión incluyeron neoplasias malignas, neutropenia, trasplantes o tratamiento inmunosupresor. Se analizaron los datos clínicos durante un seguimiento de 30 días y se caracterizaron los aislamientos microbiológicos. Se incluyeron un total de 181 episodios de ITS; 97 (53,6%) fueron adquiridas en el hospital (ITS-IH) y 84 (46,4%) en la comunidad (ITS-AC). La mediana de edad fue de 62 años (RIC 54,5–71,5) y 101 (55,8%) correspondieron a pacientes de sexo masculino. La causa más frecuente de inmunosupresión fue la neoplasia activa (n = 124, 68,5%). La bacteriemia primaria se identificó en 51 (28,2%) casos, siendo los principales focos urinario (n = 34, 18,8%), intraabdominal (n = 30, 16,6%) e infección asociada a catéter (n = 24, 13.3%). Predominaron los bacilos Gram negativos (n = 150, 75,8%), destacándose Escherichia coli (n = 71, 35,9%) y Klebsiella pneumoniae (n = 30, 15,2%). Se identificaron microorganismos multirresistentes (MMR) en 67(33,8%) episodios, con mayor frecuencia en ITS-IH que en ITS-AC (3746,3% vs 1521,4%, p = 0,001). La mortalidad global a 30 días fue del 24,8% (n = 45). En conclusión, las ITS en inmunosuprimidos fueron levemente más frecuentes en el ámbito hospitalario y se asociaron con una elevada mortalidad. Un tercio de los aislamientos correspondieron a MMR.