Risk factors for Klebsiella spp. infection after solid organ transplantation: a multi-center, case-control study

Background: Klebsiella spp. are a major cause of antimicrobial-resistant hospital-acquired infections. This study aimed to identify possible risk factors for Klebsiella spp. infection during the first180 days post-transplantation. Methods: A multi-centre, retrospective, case–control study was conducted in three hospitals in Greece and Italy between 2016 and 2021, including patients aged >50 years who had undergone solid organ transplantation. Results: In total, 202 transplant patients (115 liver, 79 kidney, seven heart and four pancreas) were included in this study, of which 120 (59.4%) suffered from at least one infection due to Klebsiella spp. (141 infections). The most common site of infection was the urinary tract (48/141, 34%), and the most common species was Klebsiella pneumoniae (132/141, 93.6%). Among all Klebsiella spp. isolates, 40.3% were carbapenem-resistant. History of cardiovascular disease [odds ratio (OR) 2.06, 95% confidence interval (CI) 1.14–3.8; P=0.019] and post-transplant intensive care unit (ICU) hospitalization for ≥3 days (OR 2.08, 95% CI 1.18–3.72; P=0.012) were independently associated with Klebsiella spp. infection among all organ recipients. In liver transplant patients, post-transplant ICU hospitalization for ≥3 days (OR 2.87, 95% CI 1.25–6.78; P=0.014) was associated with Klebsiella spp. infection, and in kidney transplant patients, history of cardiovascular disease was associated with Klebsiella spp. infection (OR 2.84, 95% CI 1.12–7.48; P=0.03). Conclusion: Post-transplant ICU stay for ≥3 days and history of cardiovascular disease are associated with increased risk of Klebsiella spp. infection in solid organ transplant recipients aged >50 years.