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Azole resistance in aspergillosis Katrien Lagrou, PharmD, PhD
Azole resistance in aspergillosis
Katrien Lagrou, PharmD, PhD
Introduction
Aspergillus is ubiquitously present in the environment (air, soil, compost, water, ….)
• Broad range of diseases: acute invasive infections, chronic invasive infections, chronic non-invasive forms, allergic syndromes
• >200,000 life-threatening infections/year worldwide• Mortality rates >25%• Azoles are the preferred antifungal agents for prophylaxis and targeted
treatment
Prevalence of triazole resistance in Aspergillus fumigatus
Image courtesy of Bram Lestrade
• No standardized methodology (all isolates/isolates from invasive aspergillosis, ..)• Total incidence of IA not available to calculate % of IA with an azole resistant isolate
A. Alanio et al, JAC 2016, 71: 2075-2078.
BUT
Resistance development in patients
Long-term triazole treatment for aspergilloma or cavitary lung disease
Variety of resistance mechanisms
• High genetic diversity between azole-resistant isolates from unrelated patients
• Lack of sporulation and reduced growth rate may occur
Patient route
Medical azoles
Triazole resistance development: ‘patient and environmental route’
Adapted from Wageningen University and Research. Available at: www.wur.nl/upload_mm/d/7/c/7191fc8f-15cf-4b1d-984b-653a0c9db27b_Hotspot-NE-1000x1227.png. (Accessed April 2019).Verweij PE, et al. Clin Infect Dis 2016;62:362–8.
TR34/L98HTR46/Y121F/T289A
• Patients with invasive aspergillosis and chronic aspergillus diseases
• Low genetic diversity between azole-resistant isolates from unrelated patients
• No apparent fitness cost
Environmental route
Environmental resistance modifications
ITRA VOR POS
R Garcia-Rubio et al, Drugs 2017, Feb 24
Tandem repeats in the promoter and associated point mutations in the azole target gene (cyp51A) in A. fumigatus
Hot spot acquired single point mutations
R Garcia-Rubio et al, Drugs 2017, Feb 24
Three most commonly described single-point mutations in the azole target gene (cyp51A) in A. fumigatus
ITRA VOR POS
Year of first recovery of TR34/L98H and TR46/Y121F/T289A resistance mechanisms in A. fumigatus
PE Verweij et al, CID 2016, 62:362-368.
TR34/L98H
1998
2004
2005 2008-2009
2008
2011
2015
2010
TR46/Y121F/T289A
20082009
2012
20132015
2016 2017 2018No. % No. % No. %
A. fumigatusNumber of strains screened 490 100 537 100 531 100Growth on VIP Check 46 9.4 33 6.1 38 7.2Susceptibility testing
Resistant 39 8.0 26 4.8 31 5.8Susceptible 2 0.4 4 0.7 7 1.3Not performed 5 1.0 3 0.6 0 0.0
Resistance mechanismsNo CYP51A mutation 5 12.8 8 30.8 3 9.7
CYP51A gene mutationTR34/L98H 29 74.4 14 53.8 23 74.2TR34/L98H/S257T/F495I 1 2.6 0 0 0 0TR46/Y121F/T298A 4 10.3 2 7.7 3 9.7G54W 0 0 0 0 1 3.2G54E/G513A 0 0 1 3.8 0 0Other 0 0 1 3.8 1 3.2
Triazole resistance data UZ Leuven
Triazole-resistant aspergillosis in patients with hematological malignancies: retrospective cohort study from Nijmegen
Consecutive patients during 2006-2012 (n= 432):• receiving chemotherapy for AML or MDS (n=182)• allo HSCT (n=250)
Screening of all isolates for triazole resistance
Proven/probable invasive aspergillosis (n=36)
Culture of Aspergillus fumigatus from respiratory sample (n=12)
Triazole resistance (n=2)
16.7% (HIGH !!!)
5.5%
PP. Lestrade et al. JAC 2018, 73: 1389-1394.
Triazole resistance in hematological patients in UZ Leuven
17% resistance
A.R. Sharpe and T. Mercier et al., oral presentation, 14th Fungal Update, London.
17% resistance
3% resistance
‘Hotspots’ for triazole resistance selection in A. fumigatus
Specific conditions and sites are thought to exist in the environment that facilitate the emergence, amplification and spread of triazole-resistant mutations in A. fumigatus (‘hotspots’)Hotspot characteristics according to experts: Ability of A. fumigatus to grow and complete its lifecycle (to achieve genetic diversity) Presence of azole residues with activity against A. fumigatus
A. fumigatus +++Azole fungicides +++Azole R: 6.2 – 24.5%
Tweede Kamer. Available at: https://www.tweedekamer.nl/kamerstukken/brieven_regering/detail?id=2017Z16992&did=2017D35356. (Accessed April 2019).
‘Hotspots’ for triazole resistance selection in A. fumigatus
Professional green composting
A. fumigatus +++ (timing dependent)Azole fungicides +Azole R: 8.5 – 30%
A. fumigatus +++Azole fungicides +Azole R: 5.8 – 20%
Tweede Kamer. Available at: https://www.tweedekamer.nl/kamerstukken/brieven_regering/detail?id=2017Z16992&did=2017D35356. (Accessed April 2019).
CULTURE
MOLECULAR
Detection of triazole resistance in patient samples
But >50% of cultures remain negative in invasive
aspergillosis patients
Broth dilution
EUCAST
Azole resistance screening-agar
• Home made• VIPcheckTM
CULTURE
J. Guinea et al. CMI 2018. Epub ahead of print.
http://www.eucast.org/clinical_breakpoints/Version 8.1, valid from 2017-03-01
A. Espinel-Ingroff et al, AAC 2011, 55: 5150-515A. Espinel-Ingroff et al, AAC 2013, 57: 3823-3828A. Espinel-Ingroff et al, JCM 2010, 48: 3251-3257
Interpretation of susceptibility testing results
A. fumigatus A. flavus A. nigerS≤ R> S≤ R> S≤ R>
Amphotericin B EUCAST 1a 2 4b 1 2CLSI 2/4 2/4 2
Itraconazole EUCAST 1 2 1 2 4CLSI 1 1 2
Voriconazole EUCAST 1 2 2 2CLSI 1 1 2
Posaconazole EUCAST 0.125 0.25 0.5 0.5CLSI 0.5 0.25 0.5
Isavuconazole EUCAST 1 1 2 4CLSI 1 1 4
a clinical breakpoint b ECV, epidemiological cutoff value
E. Kolwijck et al. Am J Respir Crit Care Med 2016 Apr 15;
Coinfections of voriconazole-susceptible and voriconazole-resistant Aspergillus fumigatus
ICU, influenza
Kidney Tx
Kidney Tx
Voriconazole-resistant strains were genetically different from voriconazole susceptible strains precluding resistance development during therapy
Screen multiple isolates if available!
43% were culture negative
Detection of resistance associated mutations was associated with
azole treatment failure
Resistance multiplex – L98H – TR34 – T289A – Y121F
Mortality
Day 42
VCZ‐S 28%VCZ‐R 49%p=0.017
Day 90
VCZ‐S 37%VCZ‐R 62%p=0.0038
Impact of triazole resistance on mortality
159
37
VCZ S VCZ R
• Retrospective cohort study 2011 – 2015• 3 university medical centers, The Netherlands (Radboudumc – LUMC – Erasmus MC)• All patients with A. fumigatus culture positive invasive aspergillosis (N=196)
21%
19% triazole resistance prevalence
Lestrade P, et al. Clin Infect Dis 2018;10.1093/cid/ciy859.
Management of patients with IA in regions with no/minimal azole resistance in the environment
Management of patients with IA in regions with ≥ 10% environmental resistance
Management of patients with IA in regions with ≥ 10% environmental resistance
10%
AZOLE RESISTANCE
HIGHER EFFECTIVENESS OF
VORICONAZOLE
Dutch Working Party on Antibiotic Policy: guideline
https://www.nvmm.nl/media/1424/p-medische-microbiologie-nvmm-nvmm-richtlijnen-richtlijnen-170815-swab-richtlijn-mycosen-2017-draft-aug17.pdf
Need for (oral) antifungal agents to treat (triazole resistant) invasive fungal infections
Binding with ergosterolAmphotericin B and lipid formulations IV
Sterol biosynthesis - triazolesFluconazoleItraconazoleVoriconazolePosaconazoleIsavuconazole
O/IV
Cell wall biosynthesisCaspofunginAnidulafungin
MicafunginIV
Nucleic acid synthesisFlucytosine O/IV
X
Promising antifungal drugs are in the pipeline
Buil JB et al. J Antimicrob Chemother. 2017;72:2548-2552
Olorofim showed potent and consistent in vitro activity against difficult-to-treat Aspergillus spp. with intrinsic and acquired antifungal resistance due to known and unknown resistance mechanisms.
Olorofim (F901318): acts via inhibition of fungal DHODH, a key enzyme in pyrimidine biosynthesis
Conclusions
• Epidemiology of triazole resistance is evolving in Aspergillus fumigatus
• All isolates from patients who are treated for aspergillosis should be checked for triazole resistance
• Culture is unsuccessful in many patients with aspergillosis, PCR is helpful to detect the most common resistance mechanisms directly in the samples from these patients
• Are there hotspots for triazole resistance development in Belgium?• Reassessment of the handling of organic waste focusing on conditions that
reduce the growth of Aspergillus fumigatus are recommended
