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.The study of the occurrence, determinants, and distribution of health and disease within healthcare settings facilities

Healthcare epidemiology

The primary focus of healthcare epidemiology is on

infection control and the prevention of health-care associated infections

includes any activities designed to study and improve patient care outcomes

Healthcare epidemiology

•Infectious diseases can be divided into 2 categories:

1.Those acquired within healthcare facilities
2.Those acquired outside of healthcare facilities

•Infectious diseases can be divided into 2 categories:

• healthcare-associated infections

• community-acquired infections

•Frequency of healthcare-associated infections (HAIs)

-Of approximately 40 million hospitalizations per year in the U.S., an estimated 2 million patients (~5% of the total) acquire HAIs

•The most common bacterial causes of HAIs in the U.S.:

• Gram-positive cocci
• Gram-negative bacilli

Staphylococcus aureus,
coagulase-negative staphylococci,
and Enterococcus spp.

Gram-positive cocci

Escherichia coli,
Pseudomonas aeruginosa,
Enterobacter spp.,
Klebsiella spp

Gram-negative bacilli:

The sources of these pathogens are

•healthcare professionals, other healthcare workers, visitors, and the patients themselves.

involve drug-resistant bacteria.

Approximately 70% of HAIs

1. Urinary tract infections (UTIs)
2. Surgical siteinfections (also referred to as postsurgical wound infections)
3. Lower respiratory infections (primarily pneumonia)
4. Bloodstream infections (septicemia)

•The 4 most common types of HAIs, in descending order of frequency, are:

UTIs

Urinary tract infections

Surgical siteinfections

postsurgical wound infections

Lower respiratory infections

pneumonia

Bloodstream infections

septicemia

gastrointestinal diseases caused by Clostridium difficile

as Clostridium difficile-associated diseases

•Elderly patients

•Women in labor and delivery

•Premature infants and newborns

•Surgical and burn patients

•Diabetic and cancer patients

•Patients receiving treatment with steroids, anticancer drugs, antilymphocyte serum, and radiation

•Immunosuppressed patients

•Patients who are paralyzed or are undergoing renal dialysis or catheterization

Patients Most Likely to Develop HAIs

-An ever-increasing number of drug-resistant pathogens
-The failure of healthcare personnel to follow infection control guidelines
-An increased number of immunocompromised patients

The 3 major factors that combine to cause HAIs are

•Overcrowding of hospitals and shortages of healthcare staff

•The indiscriminate use of antimicrobial agents

•A false sense of security about antimicrobial agents

•Lengthy and more complicated types of surgery

•Increased use of less-highly trained healthcare workers

•Increased use of anti-inflammatory and immunosuppressant agents

•Overuse and improper use of indwelling devices

Additional Factors Contributing to HAIs

•Strict compliance with infection control guidelines

•Handwashing is the single most important measure to reduce the risks of transmitting pathogens from one patient to another or from one anatomic site to another on the same patient!

•Other means of reducing the incidence of HAIs include disinfection and sterilization techniques, air filtration, use of ultraviolet lights, isolatiion of especially infectious patients, and wearing gloves, masks, and gowns whenever appropriate.

What Can be Done to Reduce the Number of HAIs?

•is the single most important measure to reduce the risks of transmitting pathogens from one patient to another or from one anatomic site to another on the same patient!

Handwashing

•include disinfection and sterilization techniques, air filtration, use of ultraviolet lights, isolation of especially infectious patients, and wearing gloves, masks, and gowns whenever appropriate.

Other means of reducing the incidence of HAIs

The most important and most basic technique in preventing and controlling infections and preventing the transmission of pathogens is

handwashing.

•the numerous measures taken to prevent infections from occurring in healthcare settings.

Infection control

means "without infection";

Asepsis

•Precautionary measures necessary to prevent direct transfer of pathogens from person to person and indirect transfer of pathogens through the air or on instruments, bedding, equipment, and other inanimate objects (fomites)

-Medical asepsis

•Practices used to render and keep objects and areas sterile

-Surgical asepsis or sterile technique

techniques are practiced in operating rooms, labor and delivery areas, and during invasive procedures (e.g., drawing blood, injecting medications, urinary and cardiac catheterization, lumbar punctures

Surgical aseptic

clean technique

Medical asepsis

sterile technique

Surgical asepsis

the goal is to exclude pathogens

Medical Asepsis

The goal is to exclude all microorganisms

Surgical asepsis

•are to be applied to the care of ALL patients in ALL healthcare settings, regardless of the suspected or confirmed presence of an infectious agent

Standard Precautions

-They provide infection control guidelines regarding hand hygiene; wearing of gloves, masks, eye protection, and gowns; respiratory hygiene/cough etiquette; safe injection practices; lumbar puncture; cleaning of patient-care equipment; environmental control; handling of soiled linens; resuscitation devices; patient placement; and disposal of used needles and other sharps

Standard Precautions

wash after touching body fluids, after removing gloves, and between patient contacts

Handwashing

Wear gloves before touching body fluids, mucous membranes, and nonintact skin

Gloves

protect eyes, nose, mouth during procedures that cause splashes or sprays of body fluids

Mask and eye protection or face shield

Wear gown during procedures that may cause splashes or sprays of body fluids

Gown

Handle soiled equipment so as to prevent personal contamination and transfer to other patients

Patient-care equipment

Follow hospital procedures for cleaning beds, equipment, and frequently touched surfaces

Environmental control

handle linen soiled with body fluids so as to prevent personal contamination and transfer to other patients

Linen

-Prevent injuries from needles, scalpels, and other sharp devices

• Never recap needles using both hands
• place sharps in puncture-proof sharps containers
• use resuscitation devices as an alternative to mouth-tom-mouth resuscitation

Occupational health and bloodborne pathogens

Use a private room for a patient who contaminates the environment

• Body fluids include blood, secretions, and excretions

Patient placement

sterile gown (A), mask (B), and gloves (C)

Healthcare Professional Donning Personal Protective Equipment (PPE)

are used for patients who are known or suspected to be infected or colonized with highly transmissible or epidemiologically important pathogens for which additional safety precautions beyond Standard Precautions are required to interrupt trsansmission within healthcare settings

Transmission-Based Precautions

1.Contact Precautions
2.Droplet Precautions
3.Airborne Precautions

•The three types of Transmission-Based Precautions are:

(1) direct-contact (i.e., transfer of microorganisms by body surface-to- body surface), and

(2) indirect contact (i.e., transfer of microorganisms by a contaminated intermediate object).

Contact transmission is divided into 2 subgroups:

Private room, if possible. Cohort if private room is not available

Patient placement

Wear gloves when entering the room.
Change gloves after having contact with infective material that may contain high concentrations of microorganisms (fecal material and wound drainage).
Remove gloves before leaving patient room

Gloves

Wash hands with an antimicrobial agent immediately after glove removal After glove removal and handwashing, ensure that hands do not touch potentially contaminated environmental surfaces or items in the patient's room to avoid transfer of microorganisms to other patients or environments.

Wash

Wear gown when entering patient room if you anticipate that your clothing will have substantial contact with the patient, environmental surfaces, or items in the patient's room, or if the patient is incontinent, or has diarrhea, an ileostomy. a colostomy, or wound drainage not contained by a dressing. Remove gown before leaving the patient's environment and ensure that clothing does not contact potentially contaminated environmental surfaces to avoid transfer of microorganisms to other patients or environments.

Gown

Limit transport of patient to essential purposes only. During transport, ensure that precautions are maintained to minimize the risk of transmission of microorganisms to other patients and contamination of environmental surfaces and equipment.

Patient transport

Dedicate the use of noncritical patient-care equipment to a single patient. If common equipment is used, clean and disinfect between patients

Patient-Care equipment

Acute viral (hemorrhagic) conjunctivitis; acute respiratory infectious diseases or aseptic meningitis in infants and young children; chickenpox; cutaneous diphtheria; disseminated shingles; extrapulmonary tuberculosis with draining lesion; gastroenteritis in diapered or incontinent persons; impetigo; infection or colonization with multidrug-resistant organisms; major draining abscesses or wound infections; monkeypox; poliomyelitis; severe mucocutaneous herpes simplex infections; smallpox; staphylococcal scalded skin syndrome; major staphylococcal or streptococcal disease of skin, wounds, or burns; viral hemorrhagic fevers due to Lassa, Ebola, Marburg, or Crimean-Congo fever viruses

Examples of DiseasesRequiring Contact Precautions

Private, room if possible. Cohort or maintain spatial separation of 3-feet from other patients or visitors if private room is not available

Patient placement

Wear mask when working within 3 feet of patient or upon entering room

Mask

Limit transport of patient from room to essential purposes only.
Use surgical mask on patient during transport

Patient

Adenovirus infection in infants and young children; adenovirus pneumonia; epiglottitis or meningitis caused by Haemophilus influenzae type b; major skin, wound, or burn infections due to group A streptococcus; scarlet fever in infants and young children; influenza; meningitis or pneumonia caused by Neisseria meningitidis; mumps; Mycoplasma pneumonia; parvovirus B19 skin infection; whooping cough; pharyngeal diphtheria; pneumonic plague; German measles; severe acute respiratory syndrome (SARS); strep throat in infants and young children; rhinovirus infection; viral hemorrhagic fevers due to Lassa, Ebola, Marburg, or Crimean-Congo fever viruses

Examples of DiseasesRequiring Droplet Precautions

Use private room that has:

• monitored negative air pressure
• 6 to 12 air changes per hour
• discharge of air outdoors or HEPA filtration if recirculated

Keep room door closed and patient in room

Patient Placement

Wear an N95 respirator when entering the room of a patient with known or suspected infectious pulmonary tuberculosis.

Susceptible persons should not enter the room of patients known or suspected to have measles (rubeola) or varicella (chickenpox) if other immune caregivers are available. It susceptible persons must enter, they should wear an N95 respirator. (Respirator or surgical mask not required if immune to measles and varicella.)

Respiratory protection

Limit transport of patient from room to essential purposes only. Use surgical mask on patient during transport.

Patient Transport

is used when Airborne Precautions are indicated

A type N95 respirator

•The preferred placement for patients who are infected with pathogens that are spread via airborne droplet nuclei (5 mm or less in diameter), and therefore require Airborne Precautions, is an airborne infection isolation room (AIIR)

Airborne Infection Isolation Room

is under negative pressure to prevent room air from entering the corridor

An AIIR

The air evacuated from an AIIR passes through a

HEPA filter

•Patients who are especially vulnerable to infection are placed in a Protective Environment - patients with severe burns or leukemia, transplant or immuno-suppressed patients, patients receiving radiation treatment, leukopenic patients, premature infants

Protective Environments

•and air entering the room passes through HEPA filters

The room is under positive pressure

•patients with severe burns or
leukemia,
transplant
immuno-suppressed patients,
patients receiving radiation treatment,
leukopenic patients,
premature infants

Protective Environment

•Some of the regulations for safe handling of food and eating utensils include:
-Using high-quality, fresh food
-Properly refrigerating and storing food
-Properly washing, preparing, and cooking food
-Properly disposing of uneaten food
-Covering hair and wearing clean clothes and aprons
-Thoroughly washing hands and nails before handling foods
-Keeping all cutting boards and other surfaces scrupulously clean
-Washing cooking and eating utensils in a dishwasher with a water temperature > 80oC

Handling Food and Eating Utensils

are nonliving, inanimate objects, other than food, that may harbor and transmit microbes. Examples: patients' gowns, bedding, towels, hospital equipment, telephone, computer keyboard, etc.

•Fomites

-Use disposable equipment and supplies whenever possible
-Disinfect or sterilize equipment soon after use
-Use individual equipment for each patient
-Use disposable thermometers or thermometer covers

•Transmission of pathogens by fomites can be prevented by observing certain rules:

-Follow OSHA standards for disposal of medical wastes

•General Regulations

-Sharps should be handled and disposed of properly
-Dispose of sharps in specifically designed puncture-resistant containers ("sharps containers")

•Disposal of Sharps

All healthcare facilities should have

some type of formal infection control program in place.

•is composed of representatives from most of the hospital's departments, including medical and surgical services, pathology, nursing, hospital administration, risk management, pharmacy, housekeeping, food services, and central supply.

The Infection Control Committee (ICC)

-is usually an infection control professional such as an epidemiologist or infectious disease specialist, an infection control nurse, or a microbiologist.

The chairperson

•CML personnel participate in infection control by:
-Monitoring the types and numbers of pathogens isolated from hospitalized patients
-Notifying the appropriate infection control person should an unusual pathogen or an unusually high number of isolates of a common pathogen be detected
-Processing environmental samples, including samples from hospital employees, that have been collected from within the affected ward(s)

Role of the Clinical Microbiology Laboratory (CML) in Hospital Epidemiology and Infection Control

1. Taking a complete patient history
2. 
   Conducting a thorough physical examination of the patient
3. Carefully evaluating the patient's signs and symptoms
4. 
   Implementing the proper selection, collection, transport, and processing of appropriate clinical specimensS

The proper diagnosis of an infectious disease requires:

Specimens collected from patients such as blood, urine, feces, and cerebrospinal fluid (CSF), are known as

Clinical specimens

blood, bone marrow, bronchial washings, sputum, CSF, cervical and vaginal swabs, feces hair and nail clipping, pus skin scrapings, sputum, synovial fluid, throat swabs, tissue specimens, urethral discharge material, urine and urogenital secretions

• all Specimens should be of highest possible quality!

Specimens commonly submitted to the hospital's clinical Microbiology Laboratory (CML)

• there should be a close working relationship among the members of the hwalthcare team to ensure a proper diagnosis of infectious diseases

• healthcare professionals who collect and Transport specimens should exercise extreme caution during the collection and Transport of specimens

• in the laboratory, all Specimens are handled carefully, exercising standard precautions

Role of healthcare professionals in the Submission of Clinical specimens

although laboratory professionals do not themselves make diagnoses, they make laboratory observations and generate test results that assist clinicians to correctly diagnose infectious diseases and initiate appropriate therapy

Role of Healthcare Professionals in the Submission of Clinical Specimens

Are required to achieve accurate, clinically relevant laboratory results

High-quality clinical specimens

• proper specimen selection
• proper specimen collection
• proper transport of the specimen to the laboratory

The 3 components of specimen quality

The laboratory must provide written guidelines

Laboratory Policies and Procedure Manual

is ultimately responsible for its quality

The person who collects the specimen

must be properly selected

Specimens

must be properly collected

Specimen

should be collected from a site where the suspected pathogen is most likely to be found

Material (i.e. specimens)

should be obtained before antimicrobial therapy, if possible

Specimens

is the most appropriate time to collect a specimen

The acute stage of a disease

should be performed with care and tact to avoid harming the patient

Specimen collection

must be obrainted to provide enough material for all required diagnostic tests

A sufficient quantity of the specimen

should be placed or collected into a sterile container to prevent contamination.

all specimens

should be protected from heat and cold and promptly delivered to the laboratory.

specimens

must be handled with even greater care to avoid contamination of couriers, patients, and healthcare professionals.

Hazardous specimens

Whenever possible, __ container should be used.

a sterile disposable specimen

must be properly labeled and accompanied by an appropriate request slip with adequate instructions.

The specimen containers

should be collected and delivered to the lab as early in the day as possible to allow sufficient processing time

Specimen