Infectious complications such as invasive aspergillosis or infection with Stenotrophomonas maltophilia (SM) in immunocompromised patients are associated with a high mortality rate. Our report concerns a 40-year-old male newly diagnosed very severe aplastic anemia (vSAA) who in consequence of a mosquito bite was suffering from skin lesion and consecutive soft tissue phlegmon subsequent to the administration of antithymocyte globulin; a full-thickness autologous meshed skin graft successfully performed to cover skin ulcera after allogeneic stem cell transplantation (SCT). This unusual case illustrates the importance of appropriate diagnosis, anti-infective therapy and close interdisciplinary diagnostic algorithms to minimalize side effects and the selection of resistant strains and to improve patients' outcome.