Susceptibility of 100 filamentous fungi: comparison of two diffusion methods, Neo-Sensitabs and E-test, for amphotericin B, caspofungin, itraconazole, voriconazole and posaconazole.

We compared the E-test method to that of the Neo-Sensitabs tablet diffusion assay for evaluating the in vitro susceptibility of 100 clinical isolates of filamentous fungi (Aspergillus spp., Fusarium spp., Scedosporium spp., zygomycetes and other molds) to amphotericin B, itraconazole, voriconazole, caspofungin, and posaconazole. We determined the categorical agreement level between E-test minimum inhibitory concentrations (MIC) and tablet end-points, as opposed to the following disagreement parameters: very major error - resistant parameter (R) in E-test and susceptible (S) in tablet; major error - S by E-test and R by tablet; minor error - shifts between S and susceptible dose-dependent (S-DD) or S-DD and R. We also performed linear regression analyses and computed Pearson's correlation coefficients (R values) between the log transforms of MICs and the inhibition zone diameters of the five studied antifungal agents. For itraconazole we obtained 97% categorical agreement and R = -0.727. Categorical agreement for caspofungin and voriconazole was 96% and R =-0.821 and R = -0.789, respectively. For posaconazole the categorical agreement was 94% and R =-0.743. Amphotericin B exhibited a lower degree of agreement (76%, R = -0.672), especially in studies of Aspergillus spp. Our results suggest a potential value of the Neo-Sensitabs assay for in vitro susceptibility testing of molds to itraconazole, voriconazole, caspofungin and posaconazole, while amphotericin B exhibited an overall lower degree of agreement.

Influence of lipid type on bis (2-ethylhexyl)phthalate (DEHP) leaching from infusion line sets in parenteral nutrition.

BACKGROUND: Bis(2-ethylhexyl)phthalate (or DEHP) is widely used in polyvinyl chloride (PVC) tubings for its good plasticizing properties. Because it is not covalently bound to the plastic matrix, it is able to escape from PVC during the infusion of the lipid emulsions used in parenteral nutrition (PN). This creates a vector through which it can enter into contact with the patient via the nutrition admixtures infused. This study was designed to assess the potential role of the type of lipids used in PN admixtures on the quantity of DEHP leached out from PVC-based tubings. METHODS: PVC-based infusion lines, 6 commercially available lipid emulsions, and their oil base components were left in direct contact, and the amount of DEHP leached was measured by liquid chromatography. RESULTS: After a 24-hour exposure period, DEHP migration varied significantly (P = .0000152) according to lipid type. The olive oil-based emulsion Clinoleic leached the most DEHP (65.8 µg/mL intravenous fat emulsion), followed by the fish oil-based emulsion Omegaven (37.8 µg/mL). The soybean oil-based emulsions Intralipid, Medialipide, Lipidem, and Structolipid showed comparable performances, with DEHP leaching rates into the emulsion measured at 27.3, 27.8, 23.6, and 19.6 µg/mL, respectively. Results from the same experiments run on pure-form oils (soybean oil, olive oil, coconut oil, and cod liver oil) confirmed the influence of lipid type on DEHP leaching. CONCLUSION: The major DEHP leaching caused by olive oil-based emulsions raises cause for concern because DEHP presents distinctive toxic effects, including an increased risk of cholestasis.