Understanding the Infectious
Disease Process:
Standard & Transmission Based
Precautions
Russ Olmsted
Trinity Health - Livonia, MI
Olmstedr@trinity-health.org
Key Principles: It’s More Than
Presence of the Microorganism
Historical Milestones in Development
of Infection Prevention & Control
Precautions, U.S.
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1877: Separate facilities for the “Infectious Patient”
1910: Antisepsis and disinfection
1950-60: Closure of Infectious disease and TB hospitals
1970: CDC “Isolation Techniques for use in Hospitals”
1983: CDC Guideline for Isolation Precautions in Hospitals
(Disease-specific and category-based precautions including
blood and body-fluids)
1985: Universal Precautions (Mostly focused on worker
protection against bloodborne pathogens, e.g. HIV)”
1987 Body Substance Isolation
 (U WA team developed; concept was precursor to Standard
Precautions (SP) – used for all patients)
History of Infection Prevention &
Control Precautions, U.S.
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1996: Revised CDC Guidelines: Standard
Precautions
2002: MSIPC Antimicrobial Resistant Organisms
(ARO) Guidelines
2006: HICPAC, CDC; Management of Multidrug-
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2007: HICPAC, CDC; Guideline for Isolation
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resistant Organisms (MDROs) in Healthcare
Facilities Dec. – Dec. 2007 issue of AJIC vol. 35:S165-S173
Precautions: Preventing Transmission of Infectious
Agents in Health Care Settings - Dec. 2007 issue of AJIC vol.
35:S65-S164
 2006 MDRO & 2007 Isolation Precautions – must haves and full text
available for all (non-subscribers too) at: http://www.ajicjournal.org
Just a Word About Standard Precautions
(SP)
Used for all patients – even those on trans.-based precautions
Assume
that every person is potentially infected or colonized
with an organism that could be transmitted in the health care
setting
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Hand hygiene
PPE: gloves, gown, mouth-nose-eye protection, etc.
Respiratory hygiene / cough etiquette
Patient placement
Environmental cleaning and disinfection, soiled linen
Safe injection practices
SP: Precautions for Lumbar
Puncture
Surgical Mask:
placing a catheter
or injecting material spinal canal or subdural
space (ie, myelograms, LP, & spinal
or epidural anesth.)
Are providers at your
affiliate using a mask?
Reason: 3 pts. S. salivarius meningitis; mask not used by HCP
Chitnis AS, et al. Outbreak of bacterial meningitis among patients
undergoing myelography at an outpatient radiology clinic. J Am Coll Radiol.
2012 Mar;9(3):185-90
Transmission-based
Precautions
Used in addition to Standard Precautions
 Airborne
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Contact
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Droplet
Infection Prevention Strategies
Hierarchy of Controls
Administrative Controls: Respiratory
Hygiene + cough etiquette
Environmental Controls: HVAC, AIIR#
Personal Protective Equipment
# Heating, Ventilation and Air Conditioning ; Airborne Infection Isolation Room
Airborne Precautions
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For infections spread by particles that remain
suspended in the air (TB, measles, varicella [chickenpox])
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Airborne Infection Isolation Room (AIIR) (a.k.a.
“negative pressure room”)
Surgical mask on patient if necessary to leave room
Respiratory protection for healthcare personnel (HCP)
in AIIR:
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N95 or more efficient respirator – e.g. patient with active TB
disease, SARS-CoV – 2007 Isol. Prec. Table
For measles & chickenpox – only immune HCP should care for
patient; New evidence: HCP should wear N95! Gohil SK CID
2015; immune personnel developed occupational infection
AIIR exhaust should not be re-circulated in the building;
if filtered using HEPA media = OK
Contact Precautions
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For infections spread by direct or indirect contact with
patients or patient care environment (e.g., RSV, C.
difficile, MRSA, VRE, CRE, MDR-A. baumannii).
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Limit patient movement
Private room preferred
Cohort patients with the same infection status
Don gown and gloves before entering the patient room
Remove and discard gown and gloves inside the patient room
Hand hygiene immediately after leaving the patient room
Emphasis on cleaning, esp. frequently touched surfaces (bed
rails, bedside tables, lavatory surfaces, etc.).
Dedicated equipment whenever possible (e.g., stethoscopes)
Does hand hygiene compliance change when
patients are in contact precaution rooms in
ICUs?; Gilbert J, et al. AJIC 2010
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No! except
MICU RNs
more likely
(66.7%) with
CP vs
(51.6%)
without
Droplet Precautions
For infections spread by large droplets
generated by coughs, sneezes, etc. (e.g.,
Neisseria meningitidis, pertussis, seasonal
influenza).
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Face shield or goggles, and a surgical mask are worn to
prevent droplets reaching the mucous membranes of the
eyes, nose and mouth when within ~6 feet of the patient
Patients should be separated by 3-6 feet, or be grouped
with other patients with the same infection/colonization
status
Patient should wear a surgical mask when outside of the
patient room
AIIR is not needed
Coughing
and Masks
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Schlieren optics
visualize the
dispersion of
expelled air during
coughing
Both standard
mask (A) and N95
respirator (B)
prevent dispersion
of cough plume
Without any type
of mask plume
travels 1-2 m
Tang J W-T. N Engl J Med 2009;361;26
The Colonization “Iceberg” Effect
Infected and
symptomatic
Colonized with
Epidemiologically-significant
microbe; no symptoms
Colonized or Infected: What is the
difference?
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People who carry bacteria without evidence of
infection (e.g. fever, increased white blood cell
count) are colonized
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If an infection develops, it is usually from bacteria
that colonize patients
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Bacteria that colonize patients can be
transmitted from one patient to another by the
hands of healthcare workers
~ Bacteria can be transmitted even if the
patient is not infected ~
Epidemiology of MDROs is NOT necessarily
created equal nor the same across health care
settings
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…no evidence supports the use of
stringent barrier precautions to
decrease illness or death from MDROs
in LTCFs …
Additional precautions are
recommended for patients colonized
…only when they are a documented
source of transmission to others…e.g.
MRSA in resident with extensive skin
lesions that can’t be contained or
VRE in lower GI tract +
diarrhea/incontinence…”
Residents with invasive devices, e.g.
indwelling urinary catheter, feeding
tube, more likely to have MDRO.
Nicolle LE. Preventing
Infections in non-hospital
Settings: long-term care.
Emerg Infect Dis 2001;7(no.2):
205-7.
Wang L, et al. Eur J Clin
Microbiol Infect Dis. 2012
Aug;31(8):1797-804
Epidemiology of MDROs in LTCF- Are Contact
Precautions Effective?
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Setting: Residents in 122 bed skilled
nursing facility in 667 bed hospital, IL
Study Interventions:
 Contact-Isolation (CI) phase =
gowns/gloves; not confined to room [+
for VRE, MRSA; no policy related to
ESBL]
 Routine glove (RG) use phase = gloves
for care of all residents or their
environment; no contact isolation even if
culture +
Results:
Frequency of acquisition of MDRO no
different between CI vs RG;
 During RG phase personnel more likely
to wear gloves, remove them, perform
hand hygiene than during CI
Trick WE, et al. Comparison of
Routine glove use and C-I
Precautions to prevent transMission of MD bacteria in a
LTCF. J Am Geriatr Soc 2004;
52:2003-9.
Supply costs:
Gowns (15/day) CI = $92,900/yr
Gloves with RG = $2,415/yr
Take home messages: RG
preferred over CI, no incr. Risk,
and more cost effective.
Contact Precautions (CP) & Patient Safety Paradox:
Acute Care Setting
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Case Control Study: adult patients on
CP for MRSA; 2 large teaching hospitals
Care Process Results:
 Vital signs incomplete or absent
when on CP
 More days with no RN or MD
progress notes when on CP
Outcomes & Satisfaction:
 Freq. of adverse events 2x higher if
on CP
 Falls, pressure ulcers,
fluid/electrolyte disorders = 8x
higher vs. controls
 Patient dissatisfaction: 17-38% on
CP vs 3-5% for controls
Stelfox HT. JAMA 2003;
290:1899-1905
Problematic Pathogens In the Healthcare
Setting & Beyond
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Vancomycinresistant
enterococci
(VRE)1
Methicillinresistant S.
aureus
(MRSA)2
C. difficile3
Norovirus4
1
2
3
4
12 Step Program for “Antibiotics Anonymous”
http://www.mi-marr.org/LTC_toolkit.html
MARR Long-term Care Tool Kit:
PREVENT INFECTION
Step 1: Vaccinate
Step 2: Prevent conditions that lead to infection
Step 3: Get the unnecessary devices out
DIAGNOSE AND TREAT INFECTION EFFECTIVELY
Step 4: Use established criteria for diagnosis
Step 5: Use local resources
USE ANTIMICROBIALS WISELY
Step 6: Know when to say "no"
Step 7: Treat infection, not colonization/contamination
Step 8: Stop antimicrobial treatment
PREVENT TRANSMISSION
Step 9. Isolate the pathogen
Step 10. Break the chain of contagion
Step 11. Perform hand hygiene
Step 12. Identify resident with multidrug-resistant organisms
(MDROs)
MDROs in LTCFs
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The epidemiology of MDROs in LTCF differs
from other settings such as acute care. This
primarily reflects much less frequent use of
invasive devices and severity of underlying
illness.
Therefore while presence of MDROs among
residents may be high, risk of cross
transmission is low compared to acute care.
State of MI Bureau of Health
Systems, MDCH, 10/03/2001
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Guidelines for Care of Nursing Home Residents
with antimicrobial-resistant organisms (ARO)
including MRSA & VRE
 Use Standard Precautions
 Communication of infection/colonization when
transferring or admitting a resident is essential
 No regulation requires negative cultures as
prerequisite for admission to LTCF, and
federal/state rules prohibit same.
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MI Society for Infection Prevention & Control. Guidelines for
Prevention & Control of ARO. 2002
CDC Recommendations: MDRO in
LTCFs; 2006
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In LTCFs, consider the individual patient’s
clinical situation and prevalence or
incidence of MDRO in the facility when
deciding whether to implement or modify
Contact Precautions in addition to
Standard Precautions for a patient
infected or colonized with a target MDRO.
For relatively healthy residents (e.g.,
mainly independent and perhaps
colonized with MDRO) follow Standard
Precautions
CDC Recommendations: MDRO in
LTCFs; 2006
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For ill residents (e.g., those totally dependent upon
healthcare personnel for healthcare and activities of
daily living, ventilator-dependent) and for those
residents whose infected secretions or drainage
cannot be contained, use Contact Precautions in
addition to Standard Precautions.
For MDRO colonized or infected patients without
draining wounds, diarrhea, or uncontrolled
secretions, establish ranges of permitted ambulation,
socialization, and use of common areas based on
your facility-based risk assessment
Step 6: Know when to say “no”
Minimize use of broad-spectrum
antibiotics
 Avoid chronic or long-term antimicrobial
prophylaxis
 Develop a system to monitor antibiotic
use and provide feedback to
appropriate personnel
 See also new checklist from CDC;
The Core Elements of Antibiotic
Stewardship for Nursing Homes, 09/2015
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Defining Epidemiologically
Important Pathogens 2006 CDC/HICPAC
MDRO Guide
Infectious agents that have one or more of
the following characteristics:
1) A propensity for transmission within healthcare
facilities
2) Antimicrobial resistance implications
3) Associated with serious clinical disease
increased morbidity and mortality
4) A newly discovered or reemerging pathogen
Why We Should Use Concept of
Epidemiologically Important
Pathogen?
Some bad pathogens in healthcare really are not
multi-drug resistant:
– methicillin susceptible S. aureus (MSSA)
– Group A Streptococcus
– Clostridium difficile
Strategies described to control MDROs are often
applied to control epidemiologically important
organisms other than MDROs.
Pathogen Profile - Hospital A:
Cent. Line-Assoc Bloodstream Infection
(CLABSI), All Units 10/06-09/07
35
30
%
of
25
Cases
20
of
CLABSI 15
10
5
0
MRSA
MSSA
SSN
Ents
Gm neg Candida
Clostridium difficile infection by Patient Care Unit, Hospital A
Unit
4E
8E
5E
2000
MICU
Annual SJMH Rate
2009
Annual Unit Rate
2008
10 E
9E
4000
3E
SICU
CCU
2E
7E
6E
60
55
50
45
40
35
30
25
20
15
10
5
0
11 E
Rate per 10,000 Pt Days
Figure 1: Rates of CDI HCF onset HCF assoc by Patient Care Unit, '08 &
'09
Active Sureillance Cultures – Look
Before you Leap
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Availability of private rooms
Staffing needs: direct care & IPCS
Monitoring adherence with contact
precautions by personnel
Preventing unintended consequences of
placing patients in contact precautions
Decolonization therapy?
Tracking of those positive for target
MDROs & electronic alert system for
subsequent readmissions?
Diekema DJ, Edmond MB. Clin Infect Dis 2007;44 (April 15)
62% decrease in
healthcare-assoc. MRSA
infection in ICUs and 45%
in non-ICUs, VAMCs with
active surveillance + CP
Jain R, et al. NEJM 2011
Tale of Two Studies on Efficacy of Active Surveillance for MDROs
No significant
difference in incidence
of MDRO between
intervention (ASD)
& control ICUs
Huskins WC, NEJM
2011