infection cycle and prevention methods

1. The Infectious Disease Model
The Chain of Infection helps to explain the infection process.
Each link represents a component or element in the cycle, and
must be present in sequential order for infection transmission to
occur. Understanding the characteristics of each link and the
relation to the other links is important to determine
interventions and strategies to break the chain and prevent
infection. Breaking the chain of infection is the responsibility of
every healthcare professional.
Chain of
Infection

2. Exit
Transmission
Entry
Susceptible
Host
Infectious
Agent
Reservoir
Chain of
Infection

3. Infectious Agent
• Exogenous: from
outside the body
• Endogenous: from
inside the body
• Bacteria
– Bacilli
– Cocci
– Spirochetes
• Virus
• Fungi
• Rickettsia
• Protozoa
Chain of
Infection

4. Reservoir
 Storage site for growth and reproduction
 Humans: Patient’s own flora - transient or chronically colonized
• Incubating
• Active disease
• Convalescent
 Animals
 Environment
• Food, beverages, soil,
• Healthcare equipment
o Contaminated
o Handling
o Storage
Chain of
Infection

5. Mode of Exit
 Organism leaves the Reservoir
– Respiratory tract
• Cough, sneeze, talking
– Gastrointestinal tract
• Saliva, vomitus, feces
– Skin, mucous membranes
– Genitourinary tract
• Urine, semen, vaginal secretions
– Blood
– Mother to unborn child
– Artificial openings
Chain of
Infection

6. Mode of Transmission
• Contact
– Direct
– Indirect
– Droplet
• Airborne
• Other sources of infection
– Example: vector
Chain of
Infection

7. Mode of Entry
Infectious agent enters the new host
– Respiratory tract
• Breathing contaminated air droplets
– Gastrointestinal tract
• Eating, drinking, hand-to-mouth (fecal-oral route)
– Skin, mucous membranes
• Non-intact skin
• Hand-to-eye and nose
– Genitourinary tract
• Urinary tract, sex
– Blood
– Placenta-to-baby
Chain of
Infection

8. Susceptible Host
 Immune system, e.g.transplant,
extremes of age,
chemotherapy
 Barrier compromised, e.g. abrasion, burn,
device use, surgical procedure
 Additional factors, e.g. underlying disease,
medications, nutrition, stress
Chain of
Infection

9. Breaking the Chain

10. Medical Asepsis
Definition: Purposeful
Prevention of infection by
• Reducing the number of
organisms and
• Preventing their spread

11. Practices that …….
Keep environment free from contamination
+
Keep patient free of colonization by facility microbes
=
ASEPSIS
* Also protects healthcare workers

12. Asepsis: Know What Is Clean
• Clean, laundered Linen
• Dishes and utensils after running through
dishwasher or cleaned + sanitized
• Employee hands following hand hygiene
• Item thoroughly washed and/or
disinfected

13. Asepsis: Know What Is Dirty
“Dirty” – contaminated (e.g. visible soil), used item
• Examples:
• Any obviously soiled item
• The floor
• Any patient’s body fluid
• Soiled/used dressing materials
• Toilet seat soiled with patient’s body fluids
• Gloved hands following personal care

14. Asepsis: Know What Is
Sterile
Sterile = Absence of all microbes
• Sterile field
• Use sterile supplies – labeled sterile
* Example – delivered in sealed package,
e.g. gauze 4x4, urinary catheter,
intravevenous fluids

15. Asepsis: Separation & Preventing
Contamination
Keep the three conditions separate
•Don’t allow clean or disinfected items to come in
contact with dirty items
•Clean linen falls on floor – floor considered dirty
Place in laundry for washing
Remedy the contamination immediately
•When you see that dirty, clean, and sterile not
kept apart, do something immediately
•Report any observed breach in technique

16. Surgical Asepsis
(sterile technique)
Practices that keep an area
or objects free from all
microorganisms

17. Surgical Asepsis Principles
• Only sterile items are used withint the sterile
field
• Sterile persons are gowned and gloved
• Tables are serile ony at table level
• Sterile persons touch only sterile items or areas
• Unsterile persons avoid reaching over the sterile field
• The edges of anything that encloses sterile contetns
are considered unsterile
• The sterile field is created as close as possible to the
time of use

18. Principles, continued
• Sterile areas are continuously kept in view
• Sterile person keep well within the sterile area
• Sterile persons keep ontact with sterile areas
to a minimum
Practices
Surgical scrub – gowning - gloving

19. STANDARD PRECAUTIONS
(SP)
• Principle that all blood, body fluids, secretions (except
sweat), excretions, non-intact skin, and mucous
membranes may contain transmissible microbes
• Group of prevention practices that apply to all
patients, regardless of suspected or confirmed
infection status, in any setting in which
healthcare is delivered.
• Application of SP: determined by:
– the nature of the HCW-resident interaction, and
– the extent of anticipated blood, body fluid, or
pathogen exposure (e.g. only gloves for drawing
blood vs gown + gloves to dress a wound with
excess drainage)

20.  Standard Precautions
• Hand hygiene
• Personal protective equipment (PPE)
– Gloves, gown, face protection
• Patient resuscitation
• Environmental measures
– Cleaning and disinfection
– Soiled patient-care equipment
– Textiles and laundry
• Safe injection practices
• Patient placement
• Respiratory hygiene/cough etiquette
Recommendations chart: http://www.cdc.gov/ncidod/dhap/pdf/guidelines/isolation2007.pef (Table 4, pp 125, 126)

21. Hand Hygiene: Why?
• Single most important practice to reduce
the transmission of infectious agents in
healthcare settings
• Reduce risk of morbidity, mortality and
cost associated with healthcare-associated
infections
• Eliminate transient organisms and reduce
resident hand flora

22. Evidence
Chain of
Infection
The relationship between
hand hygiene and HAI’s
• Substantial evidence that hand hygiene
reduces the incidence of infections
• Historical study: Semmelweis
• More recent studies: rates lower when
antiseptic hand hygiene was performed

23. Hand Hygiene Methods
Hand hygiene is a general term that applies to either
handwashing, antiseptic handwash, alcohol-based handrub, or
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 (ABHR):
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.

24. Which Method Kills
Bacteria Better?
Good Better Best
Plain Soap Antimicrobial
soap
Alcohol-based
handrub

25. • Handwashing (HW) with water and soap
requires 40–60 seconds from start to
finish
 7 times / shift = 56 min.
• Alcohol-based handrubbing (ABHR): 20–30
seconds total;
 7 times / shift = 18 min.
• If HCW used hand hygiene for
every indication in an 8 hr shift:
– HW = 16 hours !
– ABHR = 5 hours
Time constraint
major obstacle for hand hygiene
Voss A and Widmer AF, Infect Control Hosp Epidemiol 1997:18;205-208.

26. Indications for ABHR
All situations where
soap and water are
not required

27. Dispenser Placement
and Storage
• CMS encourages use of alcohol-based hand rubs
– Dispensers in patient rooms, dining rooms and,
as determined, in all settings
• Placement in corridors and rules for storage should follow
CMS regulations
– Based on NFPA standards published in Federal
Register March 25, 2005, effective May 2005 –
(Criteria pg FR 15237)
 MSIPC website provides specific directions for
locations, e.g. distances between dispensers,
distance from electrical plates
http://www.msipc..org/advocacy.html

28. Recommended Hand
Hygiene Technique
• Handrubs
– Apply to palm of one hand, rub
hands together covering all
surfaces until dry
• Handwashing
– Wet hands with water, apply soap,
rub hands together for at least 15
seconds
– Rinse and dry with disposable
towel
– Use towel to turn off faucet
Guideline for Hand Hygiene in Health-care Settings. MMWR 2002; vol. 51, no. RR-16.

29. Indications for Hand Hygiene
NOTE: This list is too prescriptive for inclusion in a policy;
may be useful when teaching risk reduction/task
identification
• When coming on-duty and at shift completion
• Before and after patient contact
• Between all patient contacts
• Before performing invasive procedure
• Before medication preparation
• Before and after eating
• Before donning/after removing gloves
• Before and after personal restroom use

30. HH Indications, cont
• When moving from a contaminated body site to a
clean body site
• After touching inanimate objects that are likely to be
contaminated with pathogenic microorganisms
– Urine measuring/collecting containers
• After contact with objects (including equipment)
located in the patient’s environment
• After touching an animal or animal waste, e.g.
therapy dog, bird
• After touching garbage
• After smoking

31. WHEN? “My 5 Moments for Hand
Hygiene” WHO 2009

32. Hand Hygiene: Patients,
Visitors, Volunteers
• PATIENTS
– Expected minimally to perform hand hygiene before meals
and after personal toilet use
– Nursing staff to review other indications with patient
• VISITORS
– Expected minimally to perform hand hygiene before meals
and after personal restroom use
– If participating in personal patient care, nursing staff will
review product use and indications for hand hygiene

33. Additional Considerations
• Hand lotion
• Nails
• Jewelry
• Glove use
• Adherence

34. HP Barriers to adherence
• Lack of knowledge that guidelines for
hand hygiene exist
• Not recognizing opportunities during the
performance of one’s duties
• Lack of awareness for the risk of cross-
contamination of organisms

35. Best Practice
• Facility decision regarding hand hygiene
• Input into evaluation and selection of
products
• Educate – proper HH, product safety, how
and when to use
• Competency evaluation and monitoring:
observations, quizzes, skills lab, electronic
monitoring systems, data collection forms,
• Encourage patient/family empowerment

36. References/Resources
• Strategies to Prevent Healthcare-Associated
Infections Through Hand Hygiene. SHEA
August, 2014
• Canada’s Hand Hygiene Challenge 2012
• Implementing AORN Recommended Practices
for Hand Hygiene 2012
• WHO Guidelines on Hand Hygiene in
Healthcare, 2009
• Guideline for Hand Hygiene in Health Care
Settings, 2002 (HICPAC)

37. (SP) Personal Protective
Equipment (PPE)
Facewear
Personal Protective Equipment
Gown
Gloves

38. PPE: Donning and removing
How hard can it be?
A learned skill?
Does it matter?
Practice makes perfect!

39. Gloves
• Body substance – fluid and solids
• Mucous membrane contact – oral, nasal,
conjunctival, rectal, genital
• Non-intact skin – burns, surgical
incisions, open skin lesions
• Device insertion site
• Contaminated items

40. 40
Donning gloves
• If wearing gown, extend
to cover wrist of gown
Removing gloves
- Remember outside of
gloves are contaminated
• Grasp outside of glove
with opposite gloved
hand; peel off
• Hold removed glove in
gloved hand
• Slide fingers of ungloved
hand under remaining
glove at wrist
Gloves

41. Additional Barriers
• Gown: protect arms and exposed body areas
– Example: if soiling of clothes probable, procedure
likely to generate splashes
• Facewear (mask/goggles/eyewear): protect
conjunctiva, nasal mucosa and mouth
– Example: if procedure likely to generate
splash, unprotected cough,
suctioning
• Resuscitation device: Use Standard
Precautions

42. 42
Gown: protect arms and exposed body
areas
• Example: if soiling of clothes
probable, procedure likely to
generate splashes
Removing gown:
• Unfasten neck, then waist ties
• Remove gown using a peeling
motion; gown will turn inside out
• Hold removed gown away from
body, roll into a bundle and
discard in room
Gowns

43. How to Decide
• Based on nature of task
• Anticipated degree of contact
with potentially infectious
substance (anything wet)
• Level of protection needed to prevent
fluid penetration
For healthcare personnel (HP) – per
organization policy (all decisions are local)
STOP

44. (S.P.) ENVIRONMENTAL
MEASURES
• Cleaning and disinfection
– Daily room cleaning
– Periodic cleaning
– “High touch” surfaces - bedrails,
bedside tables, IV poles, call bells, door
handles, BR surfaces, computer keyboards
• Care of soiled equipment
• Textiles and laundry

45. (SP) Safe injection
practices
• Use safer needle/sharp technologies, e.g.
needles/syringes, lancets (glucometers)
• Do not recap,bend, break or hand-
manipulate used needles
• Must recap? Use 1-handed scoop
• Place used sharps in puncture-resistant
container
Resources: MIOSHA, CDC, CMS, APIC + handouts

46. (S.P.) - Patient Placement
Prioritize for single-patient room if patient
• is at increased risk of transmission
• is likely to contaminate the environment
• does not maintain appropriate hygiene
• is at increased risk of acquiring infection
• developing adverse outcomes following
infection

47. (SP) Respiratory hygiene/
cough etiquette
Defined: Source containment of infectious
respiratory secretions in symptomatic patients,
beginning at initial point of encounter, e.g.
triage and reception areas in emergency depts.
and physician offices
• Cover nose/mouth when sneezing/coughing
• Use tissues and dispose in no-touch receptacle
• Practice HH after soiling with respiratory
secretions
• Wear surgical mask or maintain spatial
separation more than 3 ft (six feet?) if possible

48. Examples: Application of SP
• Practices that reduce or eliminate
organisms
– Hand hygiene
– Clean uncontaminated supplies
– PPE/barriers
– Sterile solutions
– Sterile field when indicated
– Preparation of skin

49. Any questions?