Preventing Nosocomial Infections by liuqingyan

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									Infection Control- Preventing
    Nosocomial Infections

     Yehuda Carmeli, MD, MPH
      Division of Epidemiology,
  Tel Aviv Sourasky Medical Center
      Nosocomial Infections

• Infections acquired in hospitals
  – (or healthcare setting)
• How bad can it get ?
  – Hotel -Dieu, Paris (the largest and richest of
    all hospitals) mid-18th century
     • 1,000 beds, 3,000 patients
     • Water directly from the Seine
     • Wounds clean with shared towels
           How bad it was
• All wounds became infected
• Mortality after amputation >60%
• Puerperal fever was common, and during
  an epidemic in 1746, 95% of postpartum
  women died
• Hospitals described in 1850: “The gates
  that lead to death”
        Ignaz Semmelweis,
            1815-1865
• 1840’s: General                                      16




                            Maternal mortality, 1842
                                                       14
  Hospital of Vienna                                   12
• Divided into two                                     10
                                                        8
  clinics, alternating
                                                        6
  admissions every 24                                   4
  hours:                                                2

  – First Clinic: Doctors                               0
                                                            First Clinic   Second
    and medical students                                                    Clinic

  – Second Clinic:
    Midwives
   Semmelweis
“hand disinfection”
              The Intervention:
  Hand scrub with chlorinated lime
             solution




Hand hygiene basin at the Lying-In Women’s Hospital in Vienna, 1847.
Mortality Semmelweis
                                  Hand Hygiene: Not a New
                                         Concept
                                   Maternal Mortality due to Postpartum Infection
                                    General Hospital, Vienna, Austria, 1841-1850
                                                                     Semmelweis’ Hand
                                                                     Hygiene Intervention
                             18

                             16
    Maternal Mortality (%)




                             14

                             12

                             10

                             8

                             6

                             4

                             2

                             0
                                  1841   1842   1843   1844   1845     1946   1847   1848   1849   1850


                                                              MDs       Midwives


~ Hand antisepsis reduces the frequency of patient infections ~
                             Adapted from: Hosp Epidemiol Infect Control, 2nd Edition, 1999.
          Hand Hygiene Adherence in
                  Hospitals
 Year of Study           Adherence Rate Hospital Area
 1994 (1)                         29%               General and ICU
 1995 (2)                         41%               General
 1996 (3)                         41%               ICU
 1998 (4)                         30%               General
 2000 (5)                         48%               General

1. Gould D, J Hosp Infect 1994;28:15-30. 2. Larson E, J Hosp Infect 1995;30:88-
106. 3. Slaughter S, Ann Intern Med 1996;3:360-365. 4. Watanakunakorn C,
Infect Control Hosp Epidemiol 1998;19:858-860. 5. Pittet D, Lancet
2000:356;1307-1312.
    Self-Reported Factors for Poor
    Adherence with Hand Hygiene

 Handwashing agents cause irritation and
  dryness
 Sinks are inconveniently located/lack of sinks
 Lack of soap and paper towels
 Too busy/insufficient time
 Understaffing/overcrowding
 Patient needs take priority
 Low risk of acquiring infection from patients
  Adapted from Pittet D, Infect Control Hosp Epidemiol 2000;21:381-386.
                        Ability of Hand Hygiene
                      Agents to Reduce Bacteria on
                                 Hands
                                Time After Disinfection
                       %     log
                                      0 60         180 minutes
                      99.9   3.0
Bacterial Reduction




                      99.0   2.0                           Alcohol-based handrub
                                                           (70% Isopropanol)

                      90.0   1.0
                                                           Antimicrobial soap
                                                           (4% Chlorhexidine)

                       0.0   0.0
                                                           Plain soap
                                    Baseline
                  Adapted from: Hosp Epidemiol Infect Control, 2nd Edition, 1999.
   Efficacy of Hand Hygiene
    Preparations in Killing
            Bacteria
  Good          Better          Best




Plain Soap   Antimicrobial   Alcohol-based
             soap            handrub
                         Definitions
• Hand hygiene
   – Performing handwashing, antiseptic handwash, alcohol-based
     handrub, surgical hand hygiene/antisepsis
• Handwashing
   – Washing hands with plain soap and water
• Antiseptic handwash
   – Washing hands with water and soap or other detergents containing
     an antiseptic agent
• Alcohol-based handrub
   – Rubbing hands with an alcohol-containing preparation
• Surgical hand hygiene/antisepsis
   – Handwashing or using an alcohol-based handrub before operations
     by surgical personnel

    Guideline for Hand Hygiene in Health-care Settings. MMWR 2002;
    vol. 51, no. RR-16.
              Infection Rates:
           Surgical Handscrub vs.
                  Handrub
                                                             2 Test of
Class of            No. SSI/No.         Operations (%)      Equivalence
Contamination       Handscrub             Handrub            (p-value)

Clean              29/1485 (1.9)         32/1520 (2.1)      16.0 (<0.001)

Clean-
Contaminated       24/650    (3.7)       23/732    (3.1)     1.9   (0.09)

All                53/2135 (2.5)         55/2252 (2.4)      19.5 (<0.001)




                Parienti et al. JAMA 2002: 288(6);722-27.
         Specific Indications for
            Hand Hygiene
• Before:
   – Patient contact
   – Donning gloves when inserting a CVC
   – Inserting urinary catheters, peripheral vascular
     catheters, or other invasive devices that don’t
     require surgery
• After:
   – Contact with a patient’s skin, body fluids or
     excretions, non-intact skin, wound dressings
   – Contact with a patient’s close environment
   – Removing gloves

   Guideline for Hand Hygiene in Health-care Settings. MMWR 2002;
   vol. 51, no. RR-16.
        Effect of Alcohol-Based Handrubs
                on Skin Condition
        Self-reported skin score            Epidermal water content
 Dry    6                                  27
                                                                            Healthy
        5                                  25
        4                                  23
        3                                  21
        2                                  19
        1                                  17
                                           15
Healthy 0                                                                      Dry
               Baseline        2 weeks            Baseline      2 weeks
            Alcohol rub   Soap and water        Alcohol rub   Soap and water


   ~ Alcohol-based handrub is less damaging to the skin ~

               Boyce J, Infect Control Hosp Epidemiol 2000;21(7):438-441.
       Pasteur             Lister
“germ theory of disease”   Asepsis
Aseptic techniques
• Asepsis - Prevention of microbial
  contamination of living tissues or sterile
  materials by excluding, removing or killing
  micro-organisms.
  – Disinfectant - An agent that is intended to kill or
    remove pathogenic micro-organisms, with the
    exception of bacterial spores.
  – Pasteurization - A process that kills nonspore-
    forming micro-organisms by hot water or steam at
    65-100oC.
  – Sterilization - The complete destruction of micro-
    organisms.
         Source of organisms
• The patient
  – preparation of the site
• The environment
  – cleaning and disinfection
• Surgical tools and materials
  – sterilization
• the personnel
  – protective dressing
               Sterilization
• Critical items
  – Items which enter sterile tissue or vascular
    system.
  – High risk if any organism or spores survive.
• Complete elimination of all viable
  microorganisms including spores.
• Sterility is a probabilistic phenomenon and
  not all-or-none
  October 18, 2000:
250-million-year-old
  bacteria revived
                                         Killing Curve

                              1.00E+07
                              1.00E+06
           Viable organisms




                              1.00E+05
                              1.00E+04    cleaning
                              1.00E+03
                                                                 Resistant sub-populations
                              1.00E+02
                              1.00E+01
                              1.00E+00
                                          0   1   2   3    4     5   6   7   8
Decimal reduction time:                                   Time
Overall population=1
Resistant subpopulation= 2 , 3 , >3
Bacterial Growth Curve
                      WT
          4


          3
Log CFU




          2


          1


          0
              0   2        4     6   8

                      Time (h)
       Netherlands standard
• Shelf life determined by:
  – method of sterilization
  – equipment
  – packing material
  – transport
  – storage conditions
            Difficult to trace
• Infections (SSI) are difficult to trace to
  problem in sterilization
• Thus, we are dependent on perfect
  process, with overkill threshold.
Florence Nightingale
 “hospital hygiene”
         Patient to patient
          transmission
• Routes of transmission
  – Air born
  – Blood born
  – Fecal oral route
  – Contact
  – Vector
            Blood Borne
• HBV, HCV, HIV (and many more)
• Patient to patient: Blood transfusion
• Patient to HCW (and vice versa)
  – Primarily by needle stick
  – Surgery
  – contact of skin or mucus membranes with
    blood
     Prevention of Blood
        Transmission
• Patients to HCW:
• Universal precautions: Treat all body
  fluid as infected.
  – Use of gloves for contact with blood or
    patients secretions (except sweet)
  – Surgery –double gloving
  – Protect mucus membrane when likely to
    be contaminated
  – care with sharp objects
  *post exposure prophylaxis
  Transmission by contact
• The most important route of
  transmission today
• Transmission is usually on the hands
  of HCW
• Occasionally inanimate objects
  (stethoscopes, thermometers)
• Hands can be contaminated from the
  environment
Prevention of Transmission of
    Air Born Organisms
• Aerosol :
  – single room
  – Negative pressure & filters
  – High performance mask on entry
• Droplets:
  – Single room
  – Mask
  – Ventilated patients close-suction system
     Contact transmission is
          preventable
• Hand hygiene is the most important
  measure to prevent transmission
• Compliance is low
  – Role models are missing
  – Physical conditions are a barrier
  – Time constrains
• New advances and increased awareness
  – Hand disinfection
• New trainees will bring the change ?
      Contact precautions
• For patients with multi-resistant
  organisms
(VISA, VRE, MRSA, C. diff, others )
  – isolation
  – gloves and gowns
  – hand washing
     Standard precautions
• Incorporates the concepts of universal
  precautions and body substances
  precautions
  – Universal precautions
  – Gloves for contact with dirty/contaminated
    area
  – Change gloves between contaminated and
    clean body sites
  – HW after patient contact (even after
    gloves)
  Most Common Nosocomial
         Infections
• Blood stream infections (BSI)
• Surgical site infections (SSI)
• Nosocomial pneumonia (ventilator
  associated pneumonia) (VAP)
• Urinary tract infections (UTI)
 Most Common Nosocomial
     Pathogens (NNIS)
Gram positive:   Gram negative
• S. aureus      •   E. Coli
• Enterococci    •   Klebsiella spp.
• SCN            •   P. aeruginosa
                 •   Enterobacter spp.
Patient own flora as source of
     infecting organisms
•   GI tract- GNR and entrococci
•   Nasopharynx
•   Oral flora
•   Skin flora

• Changes in flora during hospitalization,
  and 2nd to underlying conditions
                  BSI
• Primary bacteremia- almost invariably
  associated with IV lines, more so with
  central lines.
• Organisms are mostly skin flora:
  – S. aureus
  – SCN
  – Enterococci
Preventive measures line infections
 • Reduction of use of lines
   – Duration line is in place
   – Need for line
 • Central line versus peripheral line
 • Proper insertion and care
   – Standardized aseptic techniques
      • Peripheral - hand disnfection + non sterile gloves
        + no-touch technique
      • Central and PICC - cap, mask, sterile gown,
        sterile gloves, and large sterile drape
   – Experienced personnel
      • Dedicated IV team
Preventive measures line infections
• Choice of insertion site
   – Peripheral line
       • Upper extremities rather than lower extremities
       • Arm and hand rather than upper arm
   – Central line
       • Subclavian<jugular<femoral
• Skin preparation
   – Chlorhexidine preparation better than polvidon-iodine or alcohol
• Type of catheter
   – Low risk – silicone, polyurethane, teflon
   – High risk PVC, polyethylene
   – Coated catheters – abx, silver, chlorhexidine
• Dressing
   – Transparent = gauze (risk of infection)
      Other measures for BSI
• Filters – unproven
• Antibiotic prophylaxis – not recommended
• Topical antibiotics at insertion site –
  unproven and contavertial
• Antibiotic lock prophylaxis – in neutropenic
  patients with permanent catheters –
  contravertial
• Heparin flush – for short term CVC –
  prevent thrombi, no proven effect on BSI
 More measures to prevent BSI
• Replacement
  – Peripheral lines - at 72-96h
  – Midlines ? Two weeks ?
  – Short term CVC –
     • no benefit from routine replacement
     • No infection benefit from replacement over guidewire (may
       have mechanical applications)
• Administration set replacement
  – 72-96h
  – More often (1d) for blood product, TPN, fat emulsions
• Hemodyalysis
  – AV fistula<graft (x2)<catheter (x8.5)
                 Surveillance
• Monitor site
  – Visualization of site, palpation of tract if
    needed – as clinically indicated
• Record
  – Standard form for reporting insertion, dressing
    change, removal (names, dates, details)
• Culture
  – Do not culture tips routinely
    Nosocomial Pneumonia
• Most common mechanism- aspiration
• Hospital acquired organisms colonize
  the stomach, pharynx, endotracheal
  tube
• In many cases VAP 2nd to endotracheal
  tube and manipulations
    Nosocomial pneumonia
         Pathogens:
• Mostly GNR:
  – Enterobacter spp.
  – Pseudomonas aeruginosa
  – Klebsiella spp
• Gram-positive
  – S. aureus
  – S. pneumonia
     Preventing Measures
• Body position
• Ventilator intervention
• Stress-ulcer prophylaxis (non-acid
  reducing agents)
• Selective decontamination- avoid
• Reduce invasive devices
• Improve patient condition- nutrition
                    UTI
•   Associated with urinary catheters
•   Is it required
•   Minimizing duration
•   Care of catheters
•   Patient to patient transmission
•   Closed systems

								
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