Transcript Infectious disseases in hospitals

Infection Control
by Simran S Ghatore
The pre-scientific era
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Epidemics and plagues throughout history
(black plague..)
Physicians fear of contagious disease
Hippocrates and others suspected an
unseen invisible cause
Climate and environment blamed - not the
ill, dying or dead
Microbiology - scientific era
Anton van Leeuwenhoek (1632-1722)
 Dutch linen draper
 Amateur scientist
 Grinding lenses, magnifying glasses, hobby
 First to see bacteria “little beasties”
 No link between bacteria and disease
Scientific era continued . . . . .
Ignaz Semmelweiss (1818-1865)
 Obstetrician, practised in Vienna
 Studied puerperal (childbed) fever
 Established that high maternal mortality
was due to failure of doctors to wash hands
after post-mortems
 Reduced maternal mortality by 90%
 Ignored and ridiculed by colleagues
Scientific era continued . . . . .
Louis Pasteur (1822-1895)
 French professor of chemistry
 Studied how yeasts (fungi) ferment wine
and beer
 Proved that heat destroys bacteria and
fungi
 Proved that bacteria can cause infection the “germ theory” of disease
Scientific era continued . . . . .
Joseph Lister (1827-1912)
 Scottish surgeon
 Recognised importance of Pasteur’s work
 Concerned about infection of compound
fractures and post-operative wounds
 Developed carbolic acid spray to disinfect
instruments, patient’s skin, surgeon’s skin
 Largely ignored by medical colleagues
Scientific era continued
Robert Kock (1843-1910)
 German general practitioner
 Grew bacteria in culture medium
 Showed which bacteria caused particular
diseases
 Classified most bacteria by 1900
Contemporary issues
Antibiotic resistance
 Prevalence of hospital acquired
infection
 Prion diseases - BSE  ‘mad cow disease’ - new
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variant Creutzfeldt-Jakob disease (nvCJD) (thought to be the
human equivalent) - Gerstmann-Straussler-Scheinker disease –
kuru and fatal insomnia.
-Prions are mutated proteins
-majority of prion related diseases involve neurological damage.
-not all scientists accept they are the cause of disease.
(see later)
(more info)
Antibiotic resistance
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Not a new problem - Penicillin in 1944
(A.Flemming) – 1st antibiotic – most
resistance?
Hospital “superbugs”
Methycillin Resistant Staphylococcus
Aureus [MRSA]
Vancomycin Intermediate Staphylococcus
Aureus [VISA]
Tuberculosis - antibiotic resistant form
 400 deaths per year in UK
 Up to £100,000 per patient to treat
 Annual NHS cost - £5 million!!
MRSA
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Discovered in 1981
Found on skin and in the nose of 1 in 3
healthy people - symptomless carriers
Widespread in hospitals and community
Resistant to most antibiotics
When fatal - often due to septicaemia
Hospital acquired infection
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Incidence of 10%
5,000 deaths per year - direct result of HAI
15,000 deaths per year linked to HAI
Delayed discharge from hospital
Expensive to treat [£3,500 extra]
Cost to NHS - £1 billion per year
Effective hand washing is the most effective
preventative measure
Dirty wards and re-use of disposable
equipment also blamed
Prion diseases
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Prions [“pree-ons”] - proteinaceous infectious
particles
Corrupted form of a normally harmless protein
found in mammals and birds
Causes fatal neurodegenerative diseases of
animals and humans
Animals: scrapie - sheep, bovine spongiform
encephalopathy [BSE or Mad Cow Disease]
Humans: Creutzfeldt-Jakob disease [CJD]
Prions found in blood, tonsil and appendix
tissue
Prions and surgery
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Prions cannot be
destroyed by
sterilisation
Theoretical risk of
cross infection
from contaminated
instruments and
blood transfusion
Comparisons of mortality
Deaths per year in the UK
25,000
20,000
15,000
10,000
5,000
0
RTA
SUICIDE
HAI
The nature of infection
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Micro-organisms - bacteria, fungi, viruses,
protozoa and worms
Most are harmless [non-pathogenic]
Pathogenic organisms can cause infection
Infection exists when pathogenic
organisms enter the body, reproduce and
cause disease
Hospital acquired infection
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Infection which was neither present nor
incubating at the time of admission
Includes infection which only becomes
apparent after discharge from hospital but
which was acquired during hospitalisation
(Rcn, 1995)
Also called nosocomial infection
Modes of spread
Two sources of infection:
 Endogenous or self-infection - organisms
which are harmless in one site can be
pathogenic when transferred to another
site e.g., E. coli
 Exogenous or cross-infection - organisms
transmitted from another source e.g.,
nurse, doctor, other patient, environment
(Peto, 1998)
Spread - entry and exit routes
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Natural orifices - mouth, nose, ear, eye,
urethra, vagina, rectum
Artificial orifices - such as tracheostomy,
ileostomy, colostomy
Mucous membranes - which line most
natural and artificial orifices
Skin breaks - either as a result of
accidental damage or deliberate
inoculation/incision (May, 2000)
Chain of infection
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Source/reservoir of micro-organisms
 infected person [host] or other source
Method of transmission
 hands, instruments, clothing, coughing,
sneezing, dust etc.
Point of entry
 orifices, mucous membranes, skin
Susceptible host
 low resistance to infection (May, 2000)
HAI - common bacteria
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Staphylococci - wound, respiratory and
gastro-intestinal infections
Eshericia coli - wound and urinary tract
infections
Salmonella - food poisoning
Streptococci - wound, throat and urinary
tract infections
Proteus - wound and urinary tract
infections (Peto, 1998)
HAI - common viruses
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Hepatitis A - infectious hepatitis
Hepatitis B - serum hepatitis
Human immunodeficiency virus [HIV] acquired immunodeficiency syndrome via
infected blood transfusion! [AIDS] (Peto,
1998)
Common types of HAI
Other
UTI
27%
23%
Blood
6%
Skin
10%
(May, 2000)
Lower
Wound
respiratory
11%
23%
Universal infection control
precautions
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Devised in US in the 1980’s in response to
growing threat from HIV and hepatitis B
Not confined to HIV and hepatitis B
Treat ALL patients as a potential biohazard
Adopt universal routine safe infection
control practices to protect patients, self
and colleagues from infection
Universal precautions
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Hand washing
Personal protective equipment [PPE]
Preventing/managing sharps injuries
Aseptic technique
Isolation
Staff health
Linen handling and disposal
Waste disposal
Spillages of body fluids
Environmental cleaning
Risk management/assessment
Hand washing
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Single most effective action to prevent HAI resident/transient bacteria
Correct method - ensuring all surfaces are
cleaned - more important than agent used or
length of time taken
No recommended frequency - should be
determined by intended/completed actions
Research indicates:
 poor techniques - not all surfaces cleaned
 frequency diminishes with workload/distance
 poor compliance with guidelines/training
Hand washing – areas missed
Taylor (1978) identified
that 89% of the hand
surface was missed and
that the areas of the
hands most often
missed were the fingertips, finger-webs, the
palms and the thumbs.
Personal protective equipment
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PPE when contamination or splashing with
blood or body fluids is anticipated
Disposable gloves
Plastic aprons
Face masks
Safety glasses, goggles, visors
Head protection
Foot protection
Fluid repellent gowns (May, 2000)
Sharps injuries
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Prevention
 correct disposal in appropriate container
 avoid re-sheathing needle
 avoid removing needle
 discard syringes as single unit
 avoid over-filling sharps container
Management
 follow local policy for sharps injury (May,
2000)
Aseptic technique
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Sepsis - harmful infection by bacteria
Asepsis - prevention of sepsis
Minimise risk of introducing pathogenic
micro-organisms into susceptible sites
Prevent transfer of potential pathogens
from contaminated site to other sites,
patients or staff
Follow local policy (May, 2000)
Isolation
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Single room or group
Source or protective
Source - isolation of infected patient
 mainly to prevent airborne transmission
via respiratory droplets
 respiratory MRSA, pulmonary
tuberculosis
Protective - isolation of immunosuppressed patient (May, 2000)
Significant psychological effects (Davies
et al, 1999)
Staff health
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Risk of acquiring and transmitting infection
Acquiring infection
 immunisation
 cover lesions with waterproof dressings
 restrict non-immune/pregnant staff
Transmitting infection
 advice when suffering infection
Report accidents/untoward incidents
Follow local policy (May, 2000)
Linen handling and disposal
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Bedmaking and linen changing techniques
Gloves and apron - handling contaminated
linen
Appropriate laundry bags
Avoid contamination of clean linen
Hazards of on-site ward-based laundering
NHS Executive guidelines (1995)
Follow local policy (May, 2000)
Waste disposal
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Clinical waste - HIGH risk
 potentially/actually contaminated waste
including body fluids and human tissue
 yellow plastic sack, tied prior to incineration
Household waste - LOW risk
 paper towels, packaging, dead flowers, other
waste which is not dangerously
contaminated
 black plastic sack, tied prior to incineration
Follow local policy (May, 2000)
Spillage of body fluids
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PPE - disposable gloves, apron
Soak up with paper towels, kitchen roll
Cover area with hypochlorite solution e.g.,
Milton, for several minutes
Clean area with warm water and detergent,
then dry
Treat waste as clinical waste - yellow
plastic sack
Follow local policy (May, 2000)
Environmental cleaning
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Recent concern regarding poor hygiene in
hospital environments (NHSE, 1999)
Some pathogens survive for long periods in
dust, debris and dirt
Poor hygiene standards - hazardous to
patients and staff (May, 2000)
Report poor hygiene to Domestic Services
(UKCC, 1992)
“Hospitals should do the sick no harm”
(Nightingale, 1854)
Risk assessment
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No risk of contact/splashing with
blood/body fluids - PPE not required
Low or moderate risk of contact/splashing
- wear gloves and plastic apron
High risk of contact/splashing - wear
gloves, plastic apron, gown, eye/face
protection (Rcn, 1995)
Body fluids
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Cerebrospinal fluid, peritoneal fluid, pleural
fluid, synovial fluid, amniotic fluid, semen,
vaginal secretions, and
Any other fluid containing visible blood e.g.,
urine, faeces (Rcn, 1995)
Cost of HAI
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Direct cost to NHS for:
 extended hospital stay, extra resources, extra
treatment, extra equipment, and extra
community care costs if discharged needing
follow-up
Direct cost to patient/family for:
 pain and scarring, extended stay away from
family, working days lost, family income loss,
financial strain - increased visiting etc,
increased morbidity, increased mortality
(ICNA, 1998)
Summary
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Ignaz Semmelweis in 1847 demonstrated that
washing hands saves lives
Research indicates that 10% of patients
develop HAI costing the NHS £1 billion and
20,000 deaths per year
Old bacteria are causing new problems
New viral and prion diseases are causing new
problems
Reluctance to wash hands still the single most
important cause of HAI (ICNA, 1998)
Growing concern about poor hospital hygiene
Internet sites
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http://www.icna.co.uk/
http://www.nursing-standard.co.uk/
http://www.medscape.com/
http://www.anes.uab.edu/medhist.htm
http://www.shef.ac.uk/~nhcon/
http://medweb.bham.ac.uk/nursing/
http://www.healthcentre.org.uk/hc/library
/default.htm
http://www.parliament.uk/documents/uploa
d/POSTpn247.pdf (excellent article)