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16 Cards in this Set
- Front
- Back
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Sterilization
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- Physical procedures/chemical agents to destroy all microbes (spores, virus, fungi, bacteria)
- Lipid enveloped viruses are easier to kill - Moist or dry heat (autoclave), filtration, gas (ethylene oxide, formaldehyde), chemicals (glutaraldehyde), radiation (UV, ionizing) |
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Disinfection
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- Physical procedures/chemical agents to destroy most microbes
High level: Instruments designed for invasive procedures that cannot withstand sterilization (plastics) -- moist heat, glutaraldehyde, chlorine Medium level: clean instruments or surfaces where contamination with spores unlikely -- alcohols, phenolic compounds, iodophors Low level: non-critical instruments (blood pressure cuffs, EKG electrodes, stethoscope) -- quaternary ammonium compounds Most-->least resistant: bac spores, mycobac, nonlipid/small viruses, lipid/medium viruses, bacteria, fungi |
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Antisepsis
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- Use of chemical agents on skin or other tissue to inhibit or kill microbes
- Must clean skin prior to application (organic matter can decrease effectiveness) - Alcohols are rapidly cidal but leave no residual activity - Iodophors and Chlorhexidine do leave residual activity |
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Epidemiological Risk Factors - Nosocomial Pneumonia
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- 15% of nosocomial infections
- Leading cause of death from nosocomial infection, crude mortality 35-50% - Organisms may originate from endogenous flora, other patients, visitors, environment - Risk factors: severity of underlying disease, duration of hospitilization, prior ab use, advanced age, intubation, mjr surgery, achlorhydria |
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Epidemiological Risk Factors - Nosocomial UTI
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- 25% of hospitalized patients receive urinary catheter, 15% get colonized (bacteruria)
- Rate of colonization, 5-10%/day of catheterization (50% after 14 days) - G- aerobic bacilli, VRE, Candida - Silver coated catheters have shown to decrease the incidence of G+ infections |
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Epidemiological Risk Factors - Surgical Wound Infections
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- Most caused by S. aureus (also G- bacilli)
- 12-84% may not be clinically apparent until after discharge - Risk factors: skill of surgeon, underlying disease, duration of procedure - Decrease risk with pre-operative antibiotics |
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Epidemiological Risk Factors - Candidemia
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C albicans most common isolate
- Malignancy and immunosuppresion - Surgery - Prior antibiotic therapy - Central venous catheter - Total parenteral nutrition (TPN), lipid content favors growth |
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Epidemiological Risk Factors - Device Assocaited Bacteremia
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Likelihood of infection related to:
- Number of lumens (multiple>single) - Location (central>peripheral) - Duration (>72 h) - Emergent nature of placement - Skill of venipunturist |
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Importance of infection caused by MRSA
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- Resistance via change in PBP (via mecA gene)
- Community acquired, hospital acquired, healthcare-associated community-onset |
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Importance of infection caused by CNS (coagulase-negative staph)
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- Related to invasive procedures, use of prosthetic devices
- Dense extracellular glycocalyx (attachment to plastic/metal) - 89% of ICU isolates are methicillin resistant |
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Importance of infection caused by VRE (vancomycin resistant enterococci)
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- Resistance by PBP alteration (coded by genes on plasmids or chromosome)
- Higher incidence in larger, teaching hospitals and ICUs - Risk factors: age, prolonged hospitalization, prolonged antimicrobial therapy, ICU, proximity to known VRE case - Persistent colonization in GI tract, skin (below waist), contamination of environmental surfaces |
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Importance of infection caused by Resistant G- bacilli
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- E coli, Klebsiella, Enterobacter, Pseudomonas, Serratia, Acinetobacter
- Colonized at multiple body sites (GI, skin, pharynx) |
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Importance of infection caused by Candida
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- Mortality 38%
- Increase hospital stay from 10-30 days - Colonize skin, mucous membrane, GI - Spread by hospital personnel |
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Most common microbiologic etiologies of: Nosocomial pneumonia, Line-related bloodstream infection, UTIs, Surgical site infection
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Nosocomial pneumonia
- G- bacilli Line-related bloodstream infections - MRSA, CNS, VRE, Candida UTIs – G- aerobic bacilli, VRE, Candida Surgical site infections – S aureus, G- bacilli |
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Principles of Isolation
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- Designed to protect patients and personnel
- “Standard Precautions” = routinely consider all body fluids and moist surfaces potentially infectious |
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Differentiate between the different isolation categories
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AIRBORNE PRECAUTIONS
- Prevent transmission via inhalation of droplet nuclei (TB, varicella) - Patient in private room, negative pressure, 10 exchanges/hr, use of particulate aspirator DROPLET PRECAUTIONS - Prevent transmission via larger respiratory particles/droplets/close personal contact (Group A Strep) - Particulate respirator (negative pressure not required) CONTACT PRECAUTIONS - Prevent transmission via hands of personnel or inanimate surfaces (MRSA, VRE) - Gowns and gloves, handwashing |
