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1 Dr Anita Verma MD Consultant Microbiologist Department of Medical Microbiology & Institute of Liver Studies, King’s College Hospital, Foundation, NHS trust, London
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Conflict of interest Educational grant and Speakers – Gilead, Astellas Investigator and speaker for a study - Pfizer
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Challenges in Management of Invasive Fungal Infections (IFI) in Immunocompromised (IC) Patients New mycologic challenges in IC pateints Know the Changing Epidemiology of IFI Nonspecific presentation of IFI Inadequate diagnostic methods Antifungal prophylaxis – Does it work ? Breakthrough Infections while on antifungal therapy Refractory to antifungal treatment 3
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Background: IFI in Immunocompromised Patients IFI incidence is increasing in immunocompromised (IC) hosts (SOTR & HSCT recipients ) because of The pool of IC patients is increasing dramatically external pressures from antibiotic usage use of newer and more potent chemotherapeutic agents their highly compromised immune status SOTR: solid organ transplants recipients, HSCT recipients : hematopoietic stem cell
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Epidemiology of IFI in both SOTR & HSCT Recipients Increasing incidence of mold infections SOTRHSCT Invasive candidiasis53%28% Invasive aspergillosis19%43% Cryptococcosis8%- Non-aspergillus molds8%- Endemic fungi (5%)5%- Zygomycosis2%- The Transplant-Associated Infections Surveillance Network (TRANSNET) -23 transplant centers in the US, prospective study from 2001 to 2006: epidemiology of IFI in both SOTR and HSCT recipients Clin Infect Dis. 2010, 50:1101–11, Clin Infect Dis. 2010, 50:1091–100.
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Invasive Aspergillosis Type ofIA,%DisseminatedMortality transplantrange (mean)aspergillosis, %rate, % Liver1-8 (2)50-6092 Lung3-14 (6)15-2074 Heart1-15 (5.2)20-3578 Kidney0.9 - 0 4 (.7)9-3677 Pancreas1.1 - 2.9 (1.3)NA100 Small bowel0 - 3.6% (2.2)NA100
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Mortality Of Invasive Aspergillosis in Relation To Underlying Disease Clin Infect Dis 2001;32:358 100908070605040302010 leukemia leukemia /lymphoma /lymphoma bone marrow transplant bone marrow transplant kidney transplant kidney transplant lung /heart lung /heart liver transplant liver transplant AIDS AIDS
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Inadequate Current diagnostic methods for IFI >30% Detected on autopsy In a case series involving patients with hematologic malignancy IFI high prevalence of IFI 31% detected at autopsy 77% of the patients’ deaths were related to infection This highlighted the inadequacies of current diagnostic methods for IFI Haematologica. 2006, 91:986–9
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Current limitations of classical and new Diagnostic test for IFI- Issuses Conventional methods of Microscopy and culture rarely positive because: Invasive Candidiasis (IC) Patients on antifungal prophylaxis Imaging not helpful Diagnosis is mainly clinical Invasive Aspergillosis (IA); Initially affects the lungs, easily go unoticed because no clinical symptoms Even when recognized early, suitable specimens can be difficult to obtain In LTR pts with IA - 50% who had Aspergillus in BAL,22 fold at risk of IA (Singh et al 1997) Lack of adequate diagnoses makes estimating the prevalence and incidence of IFI unreliable
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Diagnosis: Imaging- Invasive Aspergillosis Chest X-ray- nodular lesions, interstistial opacities, cavitary lesions, or pulmonary embolus pattern, or normal chest x-ray CT- valuable when chest –x-ray negative, can reveal disease as much as 5 days earlier An 18-month-old girl - Aspergillus isolated from the lung. (a) Chest radiograph showed a round opacity behind the heart. (b) CT revealed a cavitating nodule in the left lower lobe.
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Nonspecific Presentation In Immunocompromised Patients- Case Scinario 18 yrs M LCH, had BMT Admitted for Liver transplant - D1 post LTx - Ambisome -5mg/kg x7 days (fullfill criteria highrisk for mold infection) Persistant Neutropenia Changed to caspofungin ( half dose because of abnormal LFTS) D18 post LT - multiple cutaneous lesions Prior to LTX multiple courses of antifungal Previous lung Bx before LTx -ve Skin Biopsy- + hyphae Culture- Aspergilllus fumigatus Started on voriconazole + Ambisome No response x 4 weeks Immunomodulation- leukocyte infusion Resolution of skin lesion – negative for mold However 3 month later relapse of underlying dis (LCH)- BX proven Wright stain;hyphae
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Available Non Culture Methods Detection of circulating surrogate markers. 1.Serological tests - detect fungal antigens Aspergillus galactomannan ELISA (1 → 3)- β-D- glucan Mannan & anti-Mannan antibody 2. PCR-based assays - detect fungal DNA. 3. Imaging
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Serological test: β-D- glucan (BDG) Cell wall component of wide variety of fungi (not zygomycetes or Cryptococcus). Indicated for the presumptive diagnosis of IFI Sensitive with a good negative predictive value i.e. good for excluding infection. A review of 23 & meta-analyses of 16 studies containing 2979 patients gave a pooled sensitivity of 76.8% & specificity of 85.3%. (Clin Infect Dis 2011;52(6):750-70. ) Meta-analysis of 31 studies of IFD: sensitivity (80%) & specificity (82%) was found by a (excluding Pneumocystis infection). (J Clin Microbiol 2012; 50(1):7-15. )
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ANTIFUNGAL STEWARDSHIP PRE-EMPTIVE TREATMENT BASED ON BDG+ RISK FACTORS
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Intensive care unit (ICU) stay - >9 month No pos culture, ?suspected aspergillosis based on BDG+ risk factors pre-emptive treatment for IA Risk factors for IFI ALF of unknown cause Intra-abdominal bleed, bowl perf, pancreatitis, dialysis dependent, multiple viral infction adeno, CMV, EBV Augmneted immunosuppression ICU stay >1year
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Optimal Antifungal Strategy – no uniform consensus ? Invasive Fungal InfectionsIssues Prophylaxis- most effectiveVariable practice Emperical: possible- Serology+ clinical ? Which antifungal ?Duration Pre-emptive: probable infection- serology+ radiology + clinical Specific Treatment : above + tissue diagnosis- proven infection- ? role of combination therapy
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T erbinafine AmBisome Griseofulvin Fluconazole Amphocil Abelcet I traconazole Licensed Antifungals 0 2 4 6 8 10 12 195019601970198019902000 Amphotericin B Nystatin Ketoconazole Miconazole 5-Flucytosine 2010 14 Voriconazole Posaconazole Caspofungin Micafungin Anidulafungin
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Current Practices- Institutional practices of antifungal prophylaxis vary widely Survey by Singh etal LTX R (Am J Transplant 2008:8:426-31) 67 sites participated 70% performed >50 transplants annually 106 UNOS Approved Transplant Programmes 72%targeted towards high risk patients 28% used universal prophylaxis 91% employed some sort of Prophylaxis 86% used Fluconazole 14% either Ambisome 1mg/kg /or echinocandins was used mainly for mold Antifungal choices Duration of Prophylaxis 40% centres till hospital stay 20% for 1month 10% fo 3month Remainder for varied duration
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Risk of Antifungal Prophylaxis in Current Era Over one-third of the infections due to non-albicans Candida spp. Prior antifungal prophylaxis the only risk-factor for non-albicans Candida Spp 58% for non-C.albicans, and 22.7% for C. albicans infections; Mortality 25 fold higher for cases than for controls (p = 0.0002); 58% for non-C.albicans, and 22.7% for C. albicans infections; Azole resistance due to prior fluconazole usuage;Husain et al., Transplantation 2003; 27: 2023-2029
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Ecological Shift: Candidaemia in a specialist ICU 10 years epidemiology 20
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21 Invasive candidiasis due to C albicans – Refractory to Fluconazole and Ambisome Sex/ age Underlyi ng disease Risk factors Anti- fungal Prophyl axis Initial treatmentChanged to Respons e Conco mitant infectio ns 1 M 5 Yr BA, D20 Post, LTx BP, BL drains in situ Flucona zole 6mg/kg x 2wks Ambisome 3mg/kg + fluconazole 12mg/kg x 3wks Echinocandin Cleared after 2wks VRE +EBV 2 M 16 yr 2yr post tx Bowel perf, BL, drains in situ, Flucona zole- 400mg Ambisome 3mg/kg + fluconazole 12mg/kg x 3wks Echinocandin Cleared after 10 days CMV + HSV Presentation of Fungal infection –intrabdominal due to C albicans, BA –Biliary atresia, BP- bowel perforation, LTx – Liver transplant, BL-Biliary leak, C albicans came back very sensitive MICS value with normal range Refractory to Antifungal Treatment
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22 ‘Cerebral Aspergillosis While on Antifungal therapy Sex/ age Liver disease Presentation of FI after LTx Site of FI Anti-fungal Therapy Risk factors Treatment Outcome 1 F 51PBC Brain Lesion on week 11 Brain Ambisome 3mg/kg Chronic LF, & RF Ambisome+ Voriconazole alive 2 F 50 ALF (Drug) Chest infection on week 3 Lung, Brain CaspofunginPNG, RF Ambisome+ Voriconazole *Deceased 3 M 33 ALF (POD) Chest infection on week 3 Lung, Eye, Brain Caspofungin Acute RF, Re- Tx Ambisome+ Voriconazole Alive FI; Fungal infection, ALF; acute liver falure, LF; Liver failure, RF;renal failure, PBC; primary biliary cirrhosis, PNG; primary nonfunctoning graft, LTx; Liver transplantation *patient 2 – had 9 month of treatment IA was treated however diedwhile awaiting for 2 nd tx - because of graft failure and bacterial septic shock Breakthrough Infections
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New Mycologic Challenges Refractory to treatment develop breakthrough - needs further evaluation Impaired Host immune system- ?Tissue concentration of antifungals ? Tolerance or Drug-resistant Finally, immune-enhancing strategies such as the use of growth factors and/or white blood cell transfusions for the prevention and treatment of opportunistic fungal infections in immunocompromised patients remain an important area of investigation. 23
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Conclusions: Invasive Fungal Infections Way to improve IFI are- Selective antifungal prophylaxis- risk based Aggressive diagnostic approach- nonculture methods High degree of vigilance Early pre-emptive therapy Develop less damaging methods of immune suppression Immunomodulation in very high risk patients
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