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) 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

cGVHD Functional asplenia hypogammaglobAbsence of ab GVHD Infections Fig.1: Bacterial infection in late post HSCT

Level of CD4+/mm 3 and common pathogens M. Tuberculosis Varicella-zoster virus/Herpes- simplex virus P. jiroveci Candida spp. Cryptococcus spp. Cryptosporidium spp. Toxoplasma spp. CytomegalovirusM. avium intracellulare Bowden et al., 1995

Other organisms that can reactivate IntracellularBiofilmsSpores M. tuberculosisCoNSClostridium spp. HerpesCandida spp P. jiroveciPseudomonas spp. Toxoplasma spp.Others 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-resistant Enterococcus (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 (varrian Creutzfeldt – 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.

Thanks for listening!