Class 5- Healthcare Associated Infections (HAIs) Flashcards
Other terms for healthcare associated infections:
- Nosocomial infections
- Hospital acquired infections
- Hospital-onset infections
Requirements to be considered HAI
- An infection that is acquired at a healthcare facility
- Must occur 48 hours after admission/receiving care
- Or within 30 days of having a surgical procedure
HAIs occur primarily due to 4 factors:
- Host factors
- Environment
- Technology
- Human factors
What percent of HAIs is bacteria responsible for?
With Bacteria the responsible culprit for roughly 90% of all HAIs
HAIs- Host Factors
- Compromised immune system
- Extremes of age (very young/very old)
- Severity of underlying illness
- Immune dysfunction
- Chemotherapy
- Autoimmune disorders and diseases
- Poor nutrition
- Genetic factors
- Obese patients are at a higher risk of postoperative infection
- Especially for bloodstream catheter related infections in ICUs
HAIs- Environment Factors
Hospital environments promote the spread of microbial pathogens
- Proximity to other patients
- Contamination of common equipment and fomites (unwashed HCP hands)
- Exposure to water contaminated with microorganisms
- Contaminated air, water and surfaces (vehicles) can spread diseases
HAIs- Technology Factors
Positive aspects of technology
- Can provide sophisticated methods for monitoring and caring for patients
Negative aspects of technology
- New advances provide new portals of entry for infection
- Alter normal host flora
- May increase antimicrobial resistance (Triclosan)
- More invasive procedures
HAIs- Human Factors
As a result of resource cuts:
- The number and skill level of physicians have decreased
- Nontraditional and support staff now provide previously specialized nursing functions
- HCPs see more patients in less time, increasing risk of failure to observe simple prevention practices - i.e. hand washing between patients
Most common isolated pathogens from HAIs
- Coagulase-negative staphylococci (CoNS) (15.3%)
- Staphylococcus aureus (14.5%)
- Enterococcus species (12.1%)
- E. coli (9.6%)
- Pseudomonas aeruginosa (7.9%)
- Other (40.6%)
Rate of infection by pathogen also matters based on route of exposure
Quick Stats in the US
2 million patients experience an HAI each year
- 1 in 10-20 patients hospitalized develop such an infection
- Responsible for almost 100,000 deaths annually
- Associated with an extra $4.5-6.5 billion in costs
- It is estimated that at least 20% of these infections could be prevented by better hygiene and infection control procedures
What locations do HAIs most commonly occur?
- 36% occur in the urinary tract
- 20% at the surgical site
- 11% in the lung
- 11% in the bloodstream
Clear link from type of care provided to location of infection
HAIs Globally
Prevalence of HAIs in countries outside of the US and Europe are at least three times as high as the density reported from the United States
- Issues of surveillance and self monitoring
- Difficult to determine actual number of HAIs in developing countries
Critical steps to reduce HAIs
- Have a trained physician with expertise in infection prevention and control (hospital epidemiologist)
- At least one infection control practitioner per 250 beds
- Computerized surveillance system
- System of reporting HAI/colonization rates of hospitalized or at risk patients to practicing physicians and surgeons.
- Increases knowledge about who has what prior to contact
National HAI surveillance
CDC National Health Safety Network (NHSN) Has almost 4,000 participating hospitals
Measurements of HAIs
- Crude Infection Rate
- # of infections/100 admissions or discharges
- Adjusted Infection Rate
- # of infections/10000 patient days or procedures
- Device-Associated Infection rates
- (# of device-associated infections/# of device-days) x 1000 Incidence and Prevalence
HAI surveillance steps
- Collecting relevant data systematically for a specified purpose and during a defined period of time
- Managing and organizing the data
- Analyzing and interpreting the data
- Communicating the results to those empowered to make beneficial changes
Methods of surveillance for HAIs
- Hospital-wide surveillance
- Prevalence surveys
- Target surveillance
- i.e. number of infections in specific age group, or trauma unit
- Periodic surveillance
Hospital-wide surveillance
Various methods including:
- Total Chart review
- Selective medical record review
- Reports of clinical symptoms from providers
- Clinical ward rounds
- Review of laboratory reports
- Extraction of data from pharmacy records (i.e. monitoring antimicrobial use)
- Computer alerts/ automated surveillance
- Follow-up letters/calls to providers
Reductions in HAIs is best achieved by altering
- Healthcare provider behaviors
- Procedure-related techniques, conditions and other processes of care
Patient characteristics are frequently beyond our control and difficult to alter
HAI microbiologic factors
- Pathogen virulence
- Ability to survive in the hospital environment
- Adhesion
- Spore formation
- Resistance to disinfectants
- Antimicrobial resistance
- Selective pressure
Extrinsic HAI Factors
- Type of medical treatment and intervention
- Types of devices and operative procedures used
- The more expensive the equipment, the more likely its been used before
- Use of antimicrobial agents disrupting GI flora
- When the normal state of endogenous flora is altered, selective pressure favors antimicrobial agents
- Biggest culprit – Clostridium difficile (C. diff). Results of antibiotic disruption of normal GI balance
- When the normal state of endogenous flora is altered, selective pressure favors antimicrobial agents
Major types of HAIs
13 major categories of types, we will only cover the major types:
- Urinary tract infections (UTIs)
- Bloodstream infections (BSIs)
- Surgical site infections (SSIs)
- Ventilator-associated pneumonia (VAP)
Urinary Tract infections
Most common of all HAIs
- Catheter associated urinary tract infections (CA-UTI)
- 75% of UTI infections are associated with urinary catheters
- Approximately 15-25% of hospitalization received urinary catheters Prolonged use increases risk
- Catheters should only be inserted when clinically indicated, and removed as soon as no longer needed
Bloodstream Infections- septicemia (BSIs)
HAI BSIs develop in more than 250,000 patients in the US each year
- 12-25% attributable mortality for each infection
- BSIs result from a secondary source like postoperative wound, or intra-abdominal infection, UTI, or pneumonia
- Most are related to intravascular devices such as central line associated bloodstream infection (CLA-BSI)
- Pathogen portal of entry is directly into the circulatory system
Surgical site infections
Responsible for 1/4th of all HAIs
- 5% of all surgical patients develop SSIs
- SSIs account for 55% of all extra hospital days attributed to HAIs
- Programs that provide surveillance for SSI may reduce these rates as much as 35% when associated with specific surgical teams
Ventilator-associated pneumonia (VAP)
VAP occurs in 9.7% of patients receiving mechanical ventilation
- Intubation is the single most important risk factor for VAP
- Increases the risk of developing pneumonia at least sixfold and increases mortality by 55%.
- Keeping patient at 30% incline reduces risk of VAP
- Increases the risk of developing pneumonia at least sixfold and increases mortality by 55%.
Modifiable risk factors vs nonmodifiable risk factors
Nonmodifiable risks:
- Age
- Gender
- Pre-existing conditions etc.
Modifiable risk factors:
- Contaminated ventilator circuits
- Endotracheal cuff with low pressure
- Multiple patient transfers
- Supine position of the patient
- Gastric overextension.
Healthcare associated pneumonia (HCAP)
Healthcare associated pneumonia (HCAP) is the leading cause of death among hospitalized patients
Pneumonia is classified as HCAP if:
- Patient was hospitalized for 2 or more days within 90 days of the infection
- Resides in a nursing home
- Received home intravenous antimicrobial therapy, chemo, or home wound care within 30 days
- Attended a hospital or hemodialysis clinic
Important HAI Pathogen List
- Aspergillus spp – fungus
- Clostridium Difficile
- Coagulase-negative staphylococci (CoNS)
- E. coli
- Enterococcus spp.
- Hepatitis B, C
- HIV Influenza
- Non-tuberculous Mycobacteria
- Pseudomonas aeruginosa
- Staphylococcus aureus
- TB
Staphylococcus aureus
Reservoir- Humans
Route –Spread by hands of hospital personnel
Incubation- variable and indefinite
Symptoms – lesions and pustules with erythematous base, bursting of pustules leads to increased spread of bacteria.
- Often infect bedsores, surgical sites, and prosthetic site attachment.
- Initial symptoms often confused with spider bite
Communicability- as long as purulent lesions continue to drain
Enterococci bacteria
Reservoir- Humans
Route- putting hands in mouth after touching doorknob, healthcare provider’s hands if not washed
Incubation- normal inhabitants of the GI tract (colonized vs. infection)
Symptoms- depends on location of infection, red itchy skin, UTI, GI infection (mild compared to S. aureus)
Communicability- can survive on dry surfaces for as long as 4 months
Treated with vancomycin - VRE does exist
Aspergillus – Fungus
Aspergillus spp
- one of the most invasive fungi
- can disseminate several thousands of spores per cubic meter of air
- spores can remain suspended in air for long periods (airborne transmission)
- eventually settle and can contaminate surfaces (contact transmission)
- spores remain viable for months and can become airborne when dust-generating activities are performed
- spores can remain suspended in air for long periods (airborne transmission)
Clostridium Difficile (C. diff)
Reservoir- colonized or infected persons and contaminated environments.
- C. diff spores can survive for weeks to months on environmental surfaces
Route – shed in feces and spread through fecal oral route. Often transmitted between patients indirectly either on the hands of healthcare workers or contact with surfaces
Incubation- unknown (estimated to be 2-3 days after exposure)
Symptoms- Watery diarrhea, up to 15 times each day, severe abdominal pain, loss of appetite, fever, blood or pus in stool, weight loss. Some cases can lead to a hole in the intestines which can be fatal if not treated immediately
Communicability - as long as shedding occurs, + life span on environmental surface
C diff risk factors
- Compromised immune system
- Surgery of GI tract
- Chemotherapy
- Previous C. Diff infection
- Diseases of the colon
- Old age
- Recent antimicrobial use
Primarily afflicts patients in hospitals or long-term care facilities, most have conditions that require long-term treatment with antibiotics which disrupt other intestinal bacteria
Penicillin- the miracle drug
First introduced in 1937
Was extremely effective at treating serious staphyloccoal and streptococcal infections 1940s
- concept of postsurgical prophylaxis was introduced with widespread adoption
Late 1950s emergence of S. aureas resistance to penicillin in hospitals
- By 2005 95% of S. aureas is resistant to penicillin
Switch to methicillin in the 70s.
- By the 1980s methicillin resistant S. aureas (MRSA) began to spread in hospitals
- Prevalence of methicillin resistance among S. aureus isolates
- 1975 – 2.4%
- 1991- 29%
- 2001-57%
Antimicrobial resistance
Usually occurs through increased drug pressure
- Failing to complete drug regimens
- Selective mutations occurring over time gene transfer from other resistant bacteria
Changes in bacteria
- Enzyme production
- Efflux pumps that remove antimicrobial agents from cells
- Alteration to outer membrane proteins (drug permeability)
- Mutation at antimicrobial binding site
- Increased emphasis on proper use of antimicrobials and patient/drug surveillance
- Efflux pumps that remove antimicrobial agents from cells
MRSA and VRE interaction
Vancomycin is one of the last line of defenses against MRSA
- Scary interaction between VRE and MRSA
- VRE can transfer vancomycin resistance to other bacteria
- Can occur without vancomycin drug pressure
- 7 cases have been documented in USA of VRSA/MRSA
- fears of sending S. aureus back to pre-antibiotic infection rates
- VRE can transfer vancomycin resistance to other bacteria
