Antifungal Susceptibility and Pathogenic Potential of Environmental Isolated Filamentous Fungi Compared with Colonizing Agents in Immunocompromised Patients

Abstract

Infection is a major cause of morbidity and mortality in bone marrow transplant recipients and in patients with hematological malignancies. The source of infection is almost always endogenous flora or the hospital environment. The present study evaluated bone marrow transplant recipients and patients with hematological malignancies colonized and/or infected with filamentous fungi. During 1 year, environmental air samples were also taken from the bone marrow transplant unit by a modification of gravity air-setting plate (GASP) methodology. Fusarium spp. were the most prevalent genus in the fall and Cladosporium spp. in the winter. Clinically isolated strains grew better at 37 degrees C than environmental strains. According to NCCLS M-38P methods, environmental Aspergillus strains showed higher MICs to miconazol and itraconazol, and clinical Fusarium strains were less susceptible to fluconazole.

Susceptibility of environmental versus clinical strains of pathogenic Aspergillus

“…Therefore, clinical strains with increased MIC values did not result from exposure to the antifungals, especially to ITC as previously reported [4,13]. The assumption that particular strains may possess increased virulence potential [7,14] can be additionally supported by these data. The relationship between reduced susceptibility and the infectious potential of non-fumigatus strains deserves further attention.…”

“…No evidence of cross-resistance was found among the strains, and no significant difference was found when comparing the MIC values of environmental strains collected at different locations (data not shown). Our MIC range and geometric mean results for clinical strains did not differ from previous studies both when considering A. fumigatus or non-fumigatus species [4][5][6][7][10][11][12]. Comparison between environmental and clinical strains revealed significantly higher MIC values (P < 0.05) to AMB, ITC and CPF in the case of non-fumigatus clinical strains.…”

“…Aspergillus non-fumigatus strains [4][5][6][7]. The objective of this study was to determine the susceptibility profiles of a large number of environmental strains of six different species of Aspergillus to amphotericin B (AMB), itraconazole (ITC), voriconazole (VRC) and caspofungin (CPF) and to compare them with the susceptibility profiles of clinical strains.…”

Disseminated Fusarium infection in autologous stem cell transplant recipient

“…Hospital environmental contamination by fungal specimens has been demonstrated in medical literature, even in high-efficiency particulate air (HEPA) filtration-equipped units. 4,5 Although cultures of tap and shower bath water turned out negative for fungal growth in our case, it is likely that environmental sources, either hospital-related or not, might be accounted as the infection source.…”