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Fungal Research Trust 20th Anniversary Meeting June 2011 - Dr Sue Howard

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Dr Sue Howard gives a talk entitled "Aspergillus resistance - it's on the increase" to the 20th Anniversary Meeting of the Fungal Research Trust

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Fungal Research Trust 20th Anniversary Meeting June 2011 - Dr Sue Howard

  1. 1. 20 th Anniversary Meeting of the Fungal Research Trust Aspergillus resistance – it's on the increase Dr Sue Howard June 2011 London, UK
  2. 2. Aspergillus resistance – it's on the increase Dr Susan J Howard The University of Manchester Manchester Academic Health Science Centre NIHR Translational Research Facility in Respiratory Medicine University Hospital of South Manchester NHS Foundation Trust
  3. 3. Aspergillus fumigatus Aspergillus terreus Aspergillus flavus Aspergillus niger
  4. 4. Other Aspergillus species Klick MA. Identification of common Aspergillus species. CBS.
  5. 5. Intrinsic resistance in Aspergillus flavus - ++ ++ ++ + ++ - ++ fumigatus - ++ ++ ++ + ++ +/- ++ FLU ITR VOR POS RAV AMB 5FC CANDINS niger - ++ ++ ++ + ++ - ++ terreus - ++ ++ ++ + - - ++ Acquired resistance development
  6. 6. Acquired resistance <ul><li>Mostly azole resistance in A. fumigatus reported </li></ul><ul><li>1) most common species </li></ul><ul><li>2) primary therapy (itra, vori, posa) </li></ul><ul><li>Standardised methodology </li></ul><ul><li>First resistant case late 1980s </li></ul><ul><li>but most >2000 </li></ul>Denning et al, 1997. AAC 41:1364-8
  7. 7. Agenda <ul><li>How common are resistant infections? </li></ul><ul><li>What are the clinical risk factors? </li></ul><ul><li>How does resistance occur? </li></ul><ul><li>Is cross-resistance a clinical problem? </li></ul><ul><li>How can we detect resistance? </li></ul>
  8. 8. Agenda <ul><li>How common are resistant infections? </li></ul><ul><li>What are the clinical risk factors? </li></ul><ul><li>How does resistance occur? </li></ul><ul><li>Is cross-resistance a clinical problem? </li></ul><ul><li>How can we detect resistance? </li></ul>
  9. 9. Clinical azole resistance reported Frequency ~2% (0-15%)
  10. 10. overall 10% Significant increase since 2004 (Fishers exact test P<0.0001)
  11. 11. Manchester as a centre -> Specialist service for the management of aspergillosis 2009 N ational A spergillosis C entre www.nationalaspergillosiscentre.org.uk -> Susceptibility testing is routinely conducted may explain high frequency of itra resistance but does not explain the change in frequency why?
  12. 12. Denning AAC 1997;41:1364-8 Verweij DRU 2009 ;12:141-7
  13. 13. Agenda <ul><li>How common are resistant infections? </li></ul><ul><li>What are the clinical risk factors? </li></ul><ul><li>How does resistance occur? </li></ul><ul><li>Is cross-resistance a clinical problem? </li></ul><ul><li>How can we detect resistance? </li></ul>
  14. 14. Clinical data <ul><li>Clinical data were available for 14 patients </li></ul><ul><li>2 invasive aspergillosis (IA) </li></ul><ul><li>9 chronic pulmonary aspergillosis (CPA) </li></ul><ul><li>2 allergic bronchopulmonary aspergillosis (ABPA) </li></ul><ul><li>1 Aspergillus bronchitis </li></ul><ul><li>Highest frequency in those with aspergillomas </li></ul><ul><li>13 had prior azole exposure (1 – 30 months) </li></ul><ul><li>6 had low drug exposures </li></ul><ul><li>8 patients failed therapy and 5 failed to improve </li></ul><ul><li>(1 not treated) </li></ul>Howard EID 2009;15:1068-76 Howard CMI 2010; 16:683-8
  15. 15. Agenda <ul><li>How common are resistant infections? </li></ul><ul><li>What are the clinical risk factors? </li></ul><ul><li>How does resistance occur? </li></ul><ul><li>Is cross-resistance a clinical problem? </li></ul><ul><li>How can we detect resistance? </li></ul>
  16. 16. Resistance mechanism Azole drug Lanosterol Ergosterol E
  17. 17. The cyp51A gene intron start codon stop codon
  18. 18. “ hot-spots” The cyp51A gene 54 98 220 intron start codon stop codon
  19. 19. Snelders PLoS M 2009;5:e219 Holland 98 220 297 495
  20. 20. Rodriguez-Tudela AAC 2008;52:2468-72 Holland 98 220 297 495 Spain 98 54 220
  21. 21. Manchester 216 147 431 138 448 434 Bueid JAC 2010; 65:2116-8 Howard EID 2009;15:1068-76 284 219 495 Holland 98 220 297 495 Spain 98 54 220 54 98 220 28% 19% 53% 94% 3% 14% 6% 11%
  22. 22. <ul><li>Striking variety of cyp51A mutations </li></ul><ul><li>Including previously reported mutations (including the hot-spots) </li></ul><ul><li>Some novel (147, 216, 431 & 434) – as yet uncharacterised </li></ul><ul><li>Of 7 patients with multiple resistant isolates, 4 revealed different mutations over time </li></ul>Manchester findings Howard EID 2009;15:1068-76
  23. 23. Patient case <ul><li>64 M </li></ul><ul><li>COPD, bronchiectasis, Mycobacterium avium pulmonary infection </li></ul><ul><li>Chronic pulmonary aspergillosis 2003 </li></ul><ul><li>Azole susceptible A. fumigatus </li></ul><ul><li>Itra therapy </li></ul><ul><li>Low itra drug exposure (rifabutin) </li></ul><ul><li>Ambisome twice for 2wk - some clinical improvement </li></ul><ul><li>4 mo itra resistant isolate (G54R) </li></ul><ul><li>4 mo later, another itra res isolate (G54E) </li></ul><ul><li>Increased precipitins titre, radiological progression </li></ul>
  24. 25. Patient case <ul><li>Oct 2004 vori, 500 > 400 mg daily </li></ul><ul><li>Good levels (0.72-1.66mg/L) </li></ul><ul><li>Radiological and serological improvement </li></ul>
  25. 27. Patient case <ul><li>Oct 2004 vori, 500 > 400 mg daily </li></ul><ul><li>Good levels (0.72-1.66mg/L) </li></ul><ul><li>Radiological and serological improvement </li></ul>
  26. 28. Patient case <ul><li>Oct 2004 vori, 500 > 400 mg daily </li></ul><ul><li>Good levels (0.72-1.66mg/L) </li></ul><ul><li>Radiological and serological improvement </li></ul><ul><li>20 mo isolate vori resistant (G448S), posa MIC 1mg/L </li></ul>keep checking MICs! <ul><li>Sept 2006 posa therapy 800mg daily </li></ul><ul><li>Good levels (1.18-1.9mg/L) </li></ul><ul><li>Slow continued improvement </li></ul><ul><li>?same/different genetic type -> microsatellite typing </li></ul>
  27. 29. Howard EID 2009;15:1068-76
  28. 30. Evolution in the lung!
  29. 31. Environmental sampling Snelders PLoS M 2008;5:e219 ?agricultural azole use
  30. 32. Harrison E ICAAC 2009 M-1720 cyp51A mutation identified no cyp51A mutation
  31. 33. Resistance mechanism Azole drug Lanosterol Ergosterol E
  32. 34. Resistance mechanism Azole drug Lanosterol Ergosterol E E E E E E E E E
  33. 35. Al-Barrag unpublished Relative expression of CAP51A to Beta tubulin WT WT codon 138 (GGC -> TGC) codon 138 (GGC -> TGC) codon 431 (TAC -> TGC) codon 434 (GGC -> TGC) 11/04 11/04 06/05 06/05 CYP51A overexpression with target mutations
  34. 36. Resistance mechanism Azole drug Lanosterol Ergosterol E Azole Azole Azole Azole Azole Azole
  35. 37. expression of efflux transporters Al-Barrag unpublished Limited evidence in Aspergillus currently
  36. 38. Other as yet un-identified mechanisms??
  37. 39. Agenda <ul><li>How common are resistant infections? </li></ul><ul><li>What are the clinical risk factors? </li></ul><ul><li>How does resistance occur? </li></ul><ul><li>Is cross-resistance a clinical problem? </li></ul><ul><li>How can we detect resistance? </li></ul>
  38. 40. Azole cross-resistance Itra resistance = almost all Posa resistance = 74% Vori resistance = 65% Amb resistance = 0% Howard EID 2009;15:1068-76
  39. 41. Bueid JAC 2010; 65:2116-8 0% 0% 7% 3% 0% 5% 5% 5% 7% 17% 0% 14% 20%
  40. 42. Agenda <ul><li>How common are resistant infections? </li></ul><ul><li>What are the clinical risk factors? </li></ul><ul><li>How does resistance occur? </li></ul><ul><li>Is cross-resistance a clinical problem? </li></ul><ul><li>How can we detect resistance? </li></ul>
  41. 43. Detection options <ul><li>MICs slow </li></ul><ul><li>Cultures frequently falsely negative in all forms of aspergillosis </li></ul><ul><li>Direct cyp51A mutation from primary specimen </li></ul><ul><li>by real-time PCR </li></ul><ul><li> most common mutations = G54, L98, M220, TR </li></ul><ul><li>55.1% cyp51A mutations (culture –ve) </li></ul><ul><li>Pro’s and con’s </li></ul><ul><li>(other/no mutations & cost vs. -ve cultures & speed) </li></ul>Denning CID 2011; 52:1123-9 Need to do MICs still!
  42. 44. Conclusions <ul><li>Resistance is clinically significant </li></ul><ul><li>Evidence of both environmental acquisition and emergence of resistance in the lung </li></ul><ul><li>Increasing frequency </li></ul><ul><li>Risk of cross-resistance is high/limited options </li></ul><ul><li>Need to monitor susceptibility routinely </li></ul>
  43. 45. Thank you

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