Healthcare Epidemiology BY Prof. DR. Zainalabideen A. Abdulla, DTM&H., MRCPI, Ph.D., FRCPath. (U.K.) Learning Objectives Healthcare Epidemiology Is defined as the study of the occurrence, determinants, and distribution of health and disease within healthcare setting. Healthcare-Associated Infections Infectious diseases are divided into: 1. Healthcare-Associated Infections (HAIs) All infections + 14 days after discharge from the hospitals; except: 2. Community-Acquired Infections Present + During incubation when hospitalized Iatrogenic Infections caused by medical or surgical intervention, e.g. catheter infection, surgical site infections are a type of HAI Frequency of HAIs 5% of hospitalized patients Most predominant HAI: Pneumonia Bacteria in hospitals are drug-resistant; (70% of HAIs) often multidrug-resistant, e.g. Pseudomonas, MDR-TB, VRE, MRSA MRSE, HIV, Candida, Protozoa, Table Table: Shows steps to prevent resistance Modes of Transmission 1. Contact (direct & indirect) 2. Droplet 3. Airborne Patients most likely to develop HAI See list; specially immunosuppressed Major factors contributing to HAIs 1. MDR bacteria increase 2. Guidelines failure by healthcare personnel 3. Immunocompromised patients increase - Other factors including MDR, aseptic technique, training, indwelling devices Most Common Types of HAIs 1. UTIs 2. Surgical site infections 3. LRTI (Pneumonia) 4. Bloodstream infections (septicemia) 5. C. difficle -associated disease: Anaerobic, spore-forming, g+ bacillus Part of indigenous colon microbiota Produce Enterotoxin AAD Cytotoxin PMC (Superinfection with oral antibiotics; both HAIs) Reduction of HAIs Strict compliance with infection control guidelines Hand washing: The most important measure to transmission of infections: Patient Patient; Site Site Use warm water + Soap + Rub of wrist, palm, back of hands, fingers, under nails for seconds (See Figures) Dry from forearm downward to fingers Infection control 1. Break various links in the chain of infection 2. Use aseptic technique (asepsis) by: Cleanliness, hand washing, patients isolation, disinfection and sterilization Asepsis Asepsis is of two types: A. Medical asepsis: Clean technique, to exclude pathogens, e.g. gloves, masks, disinfectants. B. Surgical asepsis: Sterile technique to exclude all microbes, e.g. strict surgical aseptic techniques, scrubbing hands/fingernails, sterile wearing, sterile field, heat-sterilization of instruments Spaulding system for classification of instruments and items for patient care Critical items: Sterile from any microbe e.g. surgical instruments (steam) Semicritical items: High-level disinfection to mm and non-intact skin e.g. Endoscopes (glutaraldehyde) Non-critical items (patient care items and environmental surfaces): Low level disinfection to intact skin (70%-90% ethyl alcohol, bleach) Surgical asepsis Hair clipped/shaved Skin cleaned, scrubbed (soap/antiseptic) Skin covered (sterile plastic film or cloths) Hand washing as described Sterile: gloves, caps, masks, shoe covers Sterile: Instrument, sutures, dressing Disposable needles, syringes, sharps Floors, walls, equipment: Clean/disinfected Standard precautions To ALL patients and ALL healthcare setting Prevention of transmission of infection Semmelweis/1865 Father of Hand washing Father of Hospital Epidemiology All blood, body fluid, secretions (not sweat), non-intact skin, mm: Contain infectious agents Measures: See Figure Vaccines for healthcare personnel Personal Protective Equipment (PPE) Gloves; wash hands after use Isolation gown Mask (vs N95 respirator- with filter) Eye protection; goggles/face shield Respiratory protection; Type N95 respirator: Used with TB, Severe Acute Respiratory Syndrome (SARS), Smallpox, aerosols with influenza Patient-Care Equipment; dedicated are better Environmental control; Clean Linens; Laundered Disposal of sharps (e.g. HIV, HBV, HCV); Containers Transmission-Based Protection 1. Contact precautions; most important/frequent 2. Droplet precautions; cough, sneezing, talking 3. Airborne precaution Patient placement Airborne infection isolation room Airborne infection Air Infection Isolation Room (AIIR): Single, Negative Pressure (prevent air from entering corridor), HEPA filter for removed air Protective Environment. Protective Isolation/Positive Pressure Isolation (prevent air from entering from corridor), sealed- single room, air enters through HEPA filters Handling food and eating utensils Hygienic precautions Dish washing at 80 Celsius Handling fomites Hygienic measures Disposable fomites Sterilization/disinfection Medical waste disposal Biohazard measures Role of Clinical Microbiology Laboratory (CML) Monitor pathogens isolated/computerized Antibiotic susceptibility report Notify about infectious diseases (ICC/ICP) Environmental sampling/source of infection: 1. Biotype*: If similar biochemical results? 2. Antibiogram*: If similar pattern? 3. Molecular epidemiology (plasmid genotyping, chromosomal DNA) * Phenotyping; but Genotyping is better