The Challenge of Bacterial Infections During Intensive Care Unit Stay After Heart Transplantation

Infections occurring in the early post-heart transplant (HT) period heavily contribute to morbidity and mortality. Our goal is to evaluate the incidence of hospital-acquired pneumonia/ventilator-associated pneumonia (HAP/VAPs) and/or bloodstream infections (BSIs) after HT during the intensive care unit (ICU) stay and identify their associated risk factors in our tertiary hospital.

Observational prospective study including all adult patients who consecutively underwent HT from January 1, 2015 to August 31, 2023 at Fondazione IRCCS Policlinico San Matteo, Pavia, Italy. HAP/VAPs and BSIs diagnosed during ICU were included in the analysis.

A total of 106 patients were included, 38 of whom had at least one infectious episode (35.8%), for a total of 57 independent episodes and their incidence was 2.2 per 100 days (95% CI 1.7-2.8). Length of ICU stay was 8 days (IQR: 6-11) for patients without infectious events and 27 days (IQR 14-52) for those with infectious events (p < 0.001). Gram-negative bacteria were associated with 62.8% of BSIs (mainly Enterobacterales) and with 77.9% of HAP/VAP, in this setting Pseudomonas aeruginosa accounted for 17.6% of infections while Klebsiella spp. accounted for 22.1% of infections. Colonization with resistant bacteria (HR 2.21, 95% CI 1.12-4.35) was associated with increased risk of infections while perioperative antimicrobial prophylaxis (PAP) covering Gram-negative bacteria at transplant (HR 0.45, 95% CI 0.23-0.90, p = 0.023) was a protective factor.

This study shows that Gram-negative infections represent the major challenge for HT patients during ICU stay and shows some evidence in support of the PAP covering Gram-negative infections at transplant.