Health Care Epidemiology & HAIs

• Health care epidemiology studies health and disease within healthcare settings.
• The primary focus of health care epidemiology is on infection control and preventing healthcare-associated infections.
• Health care epidemiology aims to study and improve patient care outcomes.

Healthcare-Associated Infections (HAIs)

• Infectious diseases fall into two categories: those acquired in healthcare facilities, known as HAIs, and those acquired outside, called community-acquired infections.
• Approximately 4% of hospitalized patients in the United States acquire HAIs, which equates to about 2 million out of 40 million hospitalizations per year.

Common Pathogens in HAIs

• Gram-positive bacteria like Staphylococcus aureus, coagulase-negative staphylococci, Enterococcus species, and Clostridium difficile
• Gram-negative bacteria like Escherichia coli, Pseudomonas aeruginosa, Enterobacter species, and Klebsiella species
• Healthcare professionals, workers, visitors, and patients themselves are the sources of these pathogens.
• About 70% of HAIs are caused by drug-resistant bacteria.

Types of HAIs

• The most common HAIs are:
  • Clostridium difficile-associated diarrhea.
  • Urinary tract infections, or UTIs.
  • Surgical site infections.
  • Lower respiratory tract infections, especially pneumonia.
  • Bloodstream infections, also known as septicemia.

Patients at High Risk for HAIs

• The groups that are most likely to develop HAIs are:
  • Elderly patients
  • Women during labor and delivery
  • Premature infants and newborns
  • Surgical and burn patients
  • Those with diabetes, cancer or transplants
  • Those undergoing treatment with antibiotics, steroids, anticancer drugs, antilymphocyte serum, or radiation
  • Immunosuppressed patients
  • Patients with paralysis or undergoing renal dialysis or catheterization

Major Contributing Factors to HAIs

• The main factors that contribute to HAIs are:
  • An increasing number of drug-resistant pathogens
  • Failure to adhere to infection control guidelines
  • A growing population of immunocompromised patients.

Additional Contributing Factors to HAIs

• Overcrowded hospitals and healthcare staff shortages
• Misuse of antimicrobial agents
• A false sense of security with antimicrobial agents
• More complex and lengthy surgical procedures
• Increased use of less-trained healthcare personnel
• Increased use of anti-inflammatory and immunosuppressant agents
• Overuse and misuse of indwelling devices

Prevention Strategies for HAIs

• Strict adherence to infection control guidelines is important.
• Handwashing is critical for reducing pathogen transmission between patients and different body sites.
• Other measures include:
  • Disinfection and sterilization
  • Air filtration
  • Ultraviolet lights
  • Isolation
  • Use of PPE like gloves, masks, and gowns when required

Handwashing Technique

• Handwashing is the technique to prevent the transmission of pathogens.

Infection Prevention and Control

• Infection control includes measures to prevent infections in healthcare.
• Asepsis, meaning "without infection", has two categories: medical and surgical.

Medical Asepsis

• Includes precautions to prevent direct or indirect pathogen transfer through the air, instruments, bedding, equipment, or fomites.

Surgical Asepsis (Sterile Technique)

• Involves practices to keep objects and areas sterile.
• Surgical aseptic techniques are used in operating rooms, labor and delivery, and during procedures like drawing blood, injecting medications, or catheterization.
• Medical asepsis is a clean technique, whereas surgical asepsis is a sterile technique.
• Medical asepsis aims to exclude pathogens, while surgical asepsis aims to exclude all microbes.

Standard Precautions

• Standard Precautions should be used for all patients in all healthcare settings, no matter if an infectious agent is suspected or confirmed.
• Standard Precautions include guidelines for:
  • Hand hygiene
  • PPE (gloves, masks, eye protection, and gowns)
  • Respiratory hygiene/cough etiquette
  • Safe injection practices
  • Lumbar puncture
  • Cleaning patient-care equipment
  • Handling soiled linens
  • Resuscitation devices
  • Patient placement
  • Safe disposal of needles and sharps

Transmission-Based Precautions

• Transmission-Based Precautions are for patients with known or suspected infections of highly transmissible pathogens and require additional measures beyond Standard Precautions.
• There are three types of Transmission-Based Precautions.
  • Contact
  • Droplet
  • Airborne

Contact Precautions

• Used to prevent the spread of infections through direct contact (body surface to body surface) or indirect contact (contaminated intermediate object).
• Common conditions requiring contact precautions:
  • Open wounds with soaked dressings
  • Uncontained urine
  • Diarrhea
  • Carbapenem-resistant Enterobacteriaceae (CRE)
  • MDR-Acinetobacter
  • Cystic fibrosis
  • Human metaPneumovirus (HmPV)
  • Respiratory syncytial virus (RSV)
  • Other multidrug-resistant organisms
• Gloves and gowns must always be worn when entering the room.

Contact Enteric Precautions

• Conditions such as Norovirus and Clostridium difficile infection need Contact enteric precautions.
• For Norovirus, precautions can be discontinued when the patient is asymptomatic for two days.
• Clostridium difficile infection requires precautions for the duration of the hospitalization.
• Gloves and gown are needed to enter the room and hands must be washed with soap and water after exiting if the patient has adenovirus gastroenteritis while diapered or incontinent.

Droplet Precautions

• Diseases requiring droplet precautions include:
  • Influenza
  • Bacterial meningitis (N. meningitidis or H. influenzae)
  • Mumps
  • Pertussis (whooping cough)
  • Rhinovirus
• A mask (with or without eye shield) must be worn on entry and discarded on exit. Patients must wear a regular mask when exiting the room.

Airborne Precautions

• Diseases requiring airborne precautions include:
  • Tuberculosis (active or suspected)
  • Measles
  • Varicella/Zoster (chickenpox/shingles)
• An N95 mask must be worn unless immunity is known.
• Contact Precautions should be added if lesions are present.
• A negative airflow room and N-95 respirator masks are required.
• Patients must wear a regular mask when exiting the room.

Airborne Infection Isolation Room (AIIR)

• Utilized for patients infected with pathogens spread via airborne droplet nuclei.
• The AIIR operates under negative pressure, and the evacuated air passes through a high-efficiency particulate air (HEPA) filter.

Protective Environments

• Patients highly vulnerable to infection, such as those with severe burns, leukemia, transplants, who are immunosuppressed, undergoing radiation treatment, with leukopenia, or premature infants are placed in the a protective environment.
• In such environments, the room maintains positive pressure, and air entering the room is filtered through HEPA filters.

Food Handling

• The regulations for safe handling of food and eating utensils are:
  • Use high-quality, fresh food
  • Properly refrigerate and store food
  • Properly wash, prepare, and cook food
  • Properly dispose of uneaten food
  • Cover hair and wear clean clothes and aprons
  • Thoroughly wash hands and nails before handling foods
  • Keep all cutting boards and other surfaces scrupulously clean
  • Wash cooking and eating utensils in a dishwasher with a water temperature of >80°C.

Handling Fomites

• Fomites are nonliving objects that harbor and transmit microbes, such as gowns, bedding, and equipment.
• Rules for prevention of pathogen transmission:
  • Utilize disposable equipment whenever possible
  • Disinfect or sterilize equipment after each use
  • Employ individual equipment for each patient
  • Use disposable thermometers or thermometer covers

Medical Waste Disposal

• Follow OSHA standards for medical waste disposal.
• Handle and dispose of sharps properly in designated puncture-resistant containers.

Disinfectants Used in Healthcare Facilities

• Alcohols (60-90%): denature proteins for equipment disinfection
• Chlorine compounds: denature proteins for floors and countertops
• Glutaraldehyde: interferes with DNA and RNA to disinfect medical equipment.
• Iodine compounds: disrupt protein and nucleic acid structure and are used as antiseptics
• Phenolic compounds: disrupt cell walls and used for floors and countertops.
• Quaternary ammonium compounds: inactivate enzymes and disrupt cell membranes in floors, furniture, and walls

Infection Prevention and Control Committee (IPCC)

• Formal program required in all health care facilities.
• The IPCC includes representatives from medical and surgical services, pathology, nursing, administration, risk management, pharmacy, housekeeping, food services, and central supply.
• The chairperson is an infection control expert, epidemiologist, infectious disease specialist, infection control nurse, or a microbiologist.

Clinical Microbiology Laboratory (CML)

• CML personnel participate in infection control by:
  • Monitoring pathogen types and numbers isolated from hospitalized patients, and
  • Notifying infection control personnel of unusual pathogens or high isolate numbers, and
  • Processing environmental and employee samples from affected wards.

Concluding Remarks

• HAIs prolong hospital stays and can lead to serious complications or death.
• Insurance companies typically do not cover costs related to HAIs.
• HAIs can be prevented through education and adherence to infection control practices.
• All healthcare workers must understand the risk of HAIs, master infection control practices, and actively prevent HAIs.