Combination testing of colistin with telavancin and daptomycin.

1 Primary treatment with amphotericin B or quickly switching from azoles to amphotericin B seems to be mandatory for good clinical outcome. There is no evidence of a clear correlation between the MICs of amphotericin B and outcome of treatment , but high MICs should be taken into consideration for antifungal alternatives. 7 The combination of amphotericin B with caspofungin could have been beneficial in this case. The patient described here was exposed to azoles previously, in contrast to the majority of azole-naive patients described in the Netherlands. 1 Resistance in antifungal-exposed patients may be expected as any antimicrobial treatment is associated with selective pressure and therefore with a risk of resistance emergence. 8,9 A. fumigatus resistant to medical azoles has also been recovered from the environment. Molecular typing confirmed that environmental and clinical isolates harbouring cyp51A mutations were clustered, suggesting environmental transmission to azole-naive patients. This suggests that selection through a fungicide-based route may have taken place. 10 TR46/Y121F/ T289A-bearing strains have been found throughout the environment in the Netherlands and Belgium, but also recently in India. TR46/Y121F/T289A environmental strains in India were similar to the Dutch clinical strains. 11 All these cases may indicate the rapid and worrisome geographical spread of these new resistance mechanisms, possibly following the same path as TR34/ L98H, which now causes therapy-refractory infections worldwide. References 1 Van der Linden JW, Camps SM, Kampinga GA et al. Aspergillosis due to voriconazole highly resistant Aspergillus fumigatus and recovery of genetically related resistant isolates from domiciles. 3 Fischer J, van Koningsbruggen-Rietschel S, Rietschel E et al. Prevalence and molecular characterization of azole resistance in Aspergillus spp. isolates from German cystic fibrosis patients. 5 Snelders E, Karawajczyk A, Schaftenaar G et al. Azole resistance profile of amino acid changes in Aspergillus fumigatus CYP51A based on protein homology modelling. 6 Alanio A, Sitterie E, Liance M et al. Low prevalence of resistance to azoles in Aspergillus fumigatus in a French cohort of patients treated for haem-atological malignancies. 8 Camps SM, van der Linden JW, Li Y et al. Rapid induction of multiple resistance mechanisms in Aspergillus fumigatus during azole therapy: a case study and review of the literature. 9 Howard SJ, Cerar D, Anderson MJ et al. Frequency and evolution of azole resistance in Aspergillus fumigatus associated with treatment failure. 11 Chowdhary A, Sharma C, Kathuria S et al. Azole-resistant Aspergillus fumigatus with the environmental TR46/Y121F/T289A mutation in …