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INFECTION CONTROL IN HSCT: USE OF HEPA-FILTER BY Iyoha Osaretin DEPARTMENT OF MEDICAL MICROBIOLOGY UNIVERSITY OF BENIN TEACHING HOSPITAL BENIN CITY. Haemopoeitic Stem Cell Transplantation (HSCT) HSCT - infusion of hematopoietic stem cells from a donor into a patient ( recipient)
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INFECTION CONTROL IN HSCT: USE OF HEPA-FILTER BY IyohaOsaretin DEPARTMENT OF MEDICAL MICROBIOLOGY UNIVERSITY OF BENIN TEACHING HOSPITAL BENIN CITY
Haemopoeitic Stem Cell Transplantation (HSCT) • HSCT - infusion of hematopoietic stem cells from a donor • into a patient ( recipient) • who has received chemotherapy • which is usually marrow ablative. • It has been used increasingly to treat: neoplastic diseases, hematologic disorders, immunodeficiency syndromes, congenital enzyme deficiencies autoimmune disorders.
Classification based on the source of the transplanted haemopoeitic progenitor cells • allogeneic or syngeneic • autologous.
Phase I <30 days neutropenia breeched barrier Candida spp, Aspergillus reactivated Herpes simplex virus • PHASE II <100 days CMI GVHD/Tx Herpes simplex cause pneumonia, hepatitis and colitis with potential opportunistic super infection. Pneumocystis jiroveci and Aspergillus spp. • Phase III CMI Humoral immunity RES CMV, Varicella zoster, EBV encapsulated bacteria
Infections Fig.1: Bacterial infection in late post HSCT
Level of CD4+/mm3 and common pathogens • 400 • 200 • 100 • 50 Bowden et al., 1995
Other organisms that can reactivate CDC, 2000
Sources of infection in HSCT • Host factors (endogenous). • Reactivation of viruses (HSV, VZV, CMV) • Barrier disruption causing massive disease(mucositis, IV catheters) • Colonization with resistant flora (G-ve bacteria, Vancomycin-resistantEnterococcus (VRE), yeast) • Reactivation of parasites (Toxoplasma, Strongyloides) • Environmental factors (exogenous). • Importance of positive pressure ventilation (Aspergillus spores) • Opportunistic pathogens (Legionella, Pneumocystis jiroveci, Listeria
Organ transplant (blood production) • viral (CMV, HBV, HCV, HIV, HHV-6, HHV-7, Parvovirus, HTLV-) • Bacterial (organ contamination, TB) • Unknown (varrianCreutzfeldt – Jakob disease (vCJD), pig retroviruses) Management • Prevention is preferable to treating infection in HSCT. • Regular Hand Wash by attendant • Gut decontamination • Early Treatment of infection
Pre-transplantation screening Pre-transplantation screening of the donor, recipient and / or blood products • Recipient Screening. • Ongoing or active infection • Ecological testing for HBV, HCV, HIV, HSV, VZV, EBV, CMV, T. pallidum, T. gondii • In endemic areas, T. Cruzi, Histoplasma, Strongyloides • Donor Screening. • Serological testing for HBV, HCV, HIV, T. pallidum, T. gondii • Culture of cadaveric organs, perfusates, transplant medium • Clinical and epidermiological history, Tuberculin testing and fungal serology. • Screening for malaria, T. Cruzi, etc. • Blood products. Screening for HBV, HCV, HIV, T. pallidum. Leukocyte depleted blood reduces the risk of CMV
Post-transplantation surveillance • To guide pre-emptive therapy and monitor response to treatment. • CMV disease by PCR • Candida or infection by antigen tests. • Surveillance cultures for multi-drug resistant pathogens
Prevention of infection • Routine immunization e.g. pneumococcal, influenza • Prophylactic antimicrobials first few months following transplantation, e.g. • Co-trimoxazole, • antivirals (acroclovir, Volaciclovir, ganciclovir or valganciclovir), • antifungal (nystatin, fluconazole, or triconazole). Protocols differ between different transplant centres.
HEPA- filter: • Highly efficient particle air filter • Developed during word war 11 • Eliminates foreign particles • Filters > 0.3 microns 99.97% • Use in labs, kitchen, surgical facilities, ICU, etc.
AIR FLOW USING MOTOR/FAN NOISELESS BUT ADJUSTABLE PURIFIER INCLUDING BACTERIA AND VIRUSES IF UV IS INC. FILTER REPLACEMENT-YEARLY
GENERATES NEGATIVE IONS THAT ATTRACTS PARTICLES BECOMES TOO HEAVY AND FALLS TO THE GROUND
USES PHOTOCATALYTIC OXIDATION TECHNOLOGY PROVEN EFFECTIVE AGAINST MRSA, OTHER BACTERIA, MOLDS ETC.
Conclusion • The immunocompromised host - severe life threatening infections. • HSCT- immunocompromised state • The outcome in these patients can be improved by; prevention, including use of HEPA filter, prompt and extensive investigations , aggressive treatment.