Le resistenze agli antifungini: le conferme microbiologiche. Anna Prigitano Università degli Studi Milano

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1 Le resistenze agli antifungini: le conferme microbiologiche Anna Prigitano Università degli Studi Milano

2 Microbiological resistance Genotypic resistance presence of a particular resistance mechanism mutation in hot-spot regions of FKS1, FSK2 genes mutation in Cyp51A gene echinocandin resistance in Candida azole resistance Phenotypic resistance growth in presence of high concentrations of the drug MIC determinations fungus categorized as susceptible, intermediate or resistant

3 MIC determination Broth microdilution susceptibility testing reference methods NCCLS and EUCAST Commercial methods Etest Sensititre YeastOne

4 Microbiological resistance Primary or innate resistance fungi are resistant prior to drug exposure Candida krusei Cryptococcus Mucorales Pseudallescheria/ Scedosporium fluconazole echinocandins echinocandins fluconazole, voriconazole amphotericin B Secondary or acquired resistance appeared in response to drug exposure

5 Isolate susceptible high likelihood of therapeutic success intermediate uncertain therapeutic effect resistant in the Clinic high likelihood of failure lack of inhibition with persistence of fungal infection despite appropriate antifungal therapy Reasons of no response in presence of susceptible isolate drug pharmacokinetics and pharmacodynamics host need of cidal activity fungus (e.g. biofilm)

6 Biofilm Resistant to certain antifungals Confocal laser scanning microscopy images of Candida albicans biofilms after interacting for 22 h with Anidulafungin Anidulafungin combined with monocytes Voriconazole MIC (mg/l) Planktonic Biofilm #1 #2 #1 #2 FLUCO >256 >256 VORI >256 >256 CASPO AMB Lip AMB Untreated control biofilm Voriconazole combined with monocytes Katragkou A et al. J Infect Dis Kuhn DM et al AAC 2002

7 Antifungal resistance in Candida: our experience Confirmed by mutations in fsk1 gene 22.4% in C.parapsilosis biased by outbreak isolates Candidemia 2009 (464 isolates)* Echinocandins <2% (2 C.glabrata, 1 C. krusei isolates) Fluconazole 24.9% (C.krusei + mainly C.glabrata and C.tropicalis isolates) Candidemia in ICU (302 isolates)** 0% 12.6% (C.krusei + mainly C.parapsilosis, C.tropicalis and C. glabrata isolates) Amphotericin B 0% 0% * Infection 2014 ** JMM 2012

8 Clinical relevance of azole resistance in Candida: our experience Candidemia 2009 (464 isolates)* Candidemia in ICU (302 isolates)** Candidemia in Lombardia (101 isolates)*** Echinocandins <2% 0% 2% Fluconazole 24.9% 12.6% 14% AmphotericinB 0% 0% 0% * Infection 2014 ** JMM 2012 *** CAND-LO: A.Grancini (Policlico Milano); M.Gelmi (O.C. Brescia); E.Sala, (S.Anna Como); S.Bramati (San Gerando Monza); C.Ossi (HSR Milano); L.Lombardi (Niguarda Milano); R.Grandi (O.Sacco Milano); M.Passera (HPG23 Bergamo); C.Cavanna (S.Matteo Pavia); M.Tejada (H SanDonato Milano).

9 Resistance to azoles in Aspergillus Main mechanism reduced affinity for altered CYP51A (and CYP51B) Other mechanisms overexpression of CYP51A (and CYP51B) overexpression of drug transporters atrf, AfuMDR3, AfuMDR4, Cdr1B mutation in transcriptor factor hape

10 Aspergillus fumigatus emergence of multiple triazole resistance Since the mid-1990s, first reports from The Netherlands (also in isolates from naive patients) and UK Afterwards, increasing number of reports from around the world Hypothesis: azole resistance develops in the environment because of exposure to azole fungicides used both in agriculture and for material protection Search in Medline: Aspergillus + azole resistance papers papers papers

11 Antifungal resistance in Aspergillus: our experience SCARE Study 2009 (clinical isolates) Rate of resistance: 4/209 (2%) A. fumigatus clinical isolates screened 2% in Italy vs 0-4.2% in other countries Resistant isolates from naive patients Mechanism of resistance TR 34 /L98H: 4/4 in Italy vs 21/39 SCARE partecipants

12 Aspergillus fumigatus: azole resistance in Italy Environmental survey ( and ) 34/172 (19.7%) 19 Positive/sampled in each region Resistance % 5% 10% Isolates 31/448 (6.9%) Patients 24/378 (6.3%)

13 Implications of azole resistance Invasive aspergillosis 88% mortality rate in IA caused by a TR 34 /L98H multi-azole-resistant isolate vs 30-50% mortality rate in IA caused by a susceptible isolate Chronic aspergillosis Dissemination of resistance greatly compromises outcome for patients that need long-term oral antifungal therapy Denning DW CID 2013

14 Infections caused by multiple Aspergillus strains with different patterns of susceptibility Azole susceptible Azole resistant

15 Cultures frequently falsely negative in haematological patients PCR assay to detect the most common resistance-mediating mutations of A.fumigatus cyp51a gene from clinical samples Spiess B et al AAC 2012

16 ARTE (Aspergilli Resistenti in Trapiantati ed Ematologici) prospective multicenter study Aims to centralize Aspergillus isolates from surveillance swabs or bronchial secretions of patients with haematological malignancies or submitted to HSCT to analyze the azole susceptibility pattern of isolates, and to investigate, in the presence of resistance, the molecular mechanism to correlate the resistance to demographic and behavior variables and previous antifungal treatments. Centers Agreement to the project: 31 Active participation: 15

17 ARTE (Aspergilli Resistenti in Trapiantati ed Ematologici) Preliminary results Up to 15 Sept 2015 Collected and screened 126 Aspergillus isolates from 107 pts Azole resistance confirmed in 1 A. niger isolate 67 A.fumigatus 21 A.flavus 17 A. niger 7 A. terreus 1 A. fumigatus isolate (mutation L98H) Prevalence 1.6% 14 altre specie Study ongoing and enlarged to solid organ tranplant recipients

18 ARTE Study Group A.Candoni, A.Sartor, A.O.U Friuli Venezia Giulia, Udine M.Paolucci, M.Stanzani Università di Bologna M.Passera Ospedale Papa Giovanni XXIII, Bergamo P.Innocenti, M.Casini A.S.Alto Adige O. Bolzano L.Pitzurra Università di Perugia A.Micozzi Università La Sapienza, Roma M. Pizzolante, V.Bozzoli P.O. Vito Fazi, Lecce A.Grancini, F.Minonzio, D.Vincenti, IRCCS Policlinico Milano A.Rovellini, M.Curioni C. Fontana Policlinico TorVergata, Roma G.Amato, O.Finizio, F.Ferrara Ospedale Cardarelli Napoli M.Gelmi, M.Cattaneo Spedali Civili Brescia A. Ferrario, A. Colombo Ospedale, Varese G. LoCascio A.O.U., Verona

19 At last, but not at least Infections caused by fungi less susceptible to antifungal drugs

20 PSEUDALLESCHERIA/SCEDOSPORIUM SPP. Amb Itra MIC mg/l Vori Posa P. boydii / S. apiospermum S. prolificans In vitro suceptibility of 24 Pseudallescheria/Scedosporium spp. strains Different patterns of susceptibility: S. prolificans resistant to all antifungals tested and all species resistent to amfotericin B. Esposto M.C., FIMUA Catania 2008

21 Fusarium antifungal susceptibility: high interspecies variability F. verticilloides F. solani F. proliferatum F. oxysporum ITRA VORI POSA AmB S Scarsa S ITRA VORI POSA AmB R S ITRA VORI POSA AmB R S/R S/R S ITRA VORI POSA AmB R S/R S/R S FLUCO R ECHINO R Dati studio A. M. Tortorano, Eur J Clin Microbiol Infect Dis. 2014

22 Conclusions Susceptibility testing of clinical isolates (yeasts and molds) is increasingly important for patient management Surveillance programmes for species identification and antifungal susceptibility testing are necessary to obtain epidemiological data on antifungal resistance Detection of antifungal resistant isolates and study of resistance mechanisms essential to plan strategies to avoid it Grazie per l attenzione