Multicentre outbreak of Candida viswanathii bloodstream infections linked to contaminated milrinone, Italy, April to...

In 2025, a multicentre outbreak of bloodstream infections caused by Candida viswanathii, a rare non-albicans Candida species, was identified in Italy. The source was recognised after four C. viswanathii bloodstream infections were identified within a short period at a single centre. Initial local investigations did not identify environmental or patient-to-patient transmission. Given the strong geographical association of C. viswanathii with the Indian subcontinent, a hypothesis-driven investigation focusing on medicinal products of Indian origin was undertaken. Milrinone was the only common exposure among affected patients, and culture of the implicated product yielded C. viswanathii, confirming contamination. In total, 40 cases of C. viswanathii candidaemia were identified across four centres between April and October 2025; all were bloodstream infections. Most were associated with one predominant milrinone lot, although additional lots were implicated. Immediate control measures included withdrawal of the implicated product, notification of national authorities and active microbiological surveillance of exposed patients. This outbreak highlights the importance of clinician-led outbreak detection, hypothesis-driven epidemiology and pharmacovigilance in identifying rare, medicine-associated fungal infections.