Healthcare-associated infections (HAIs) are infections acquired during healthcare and can be caused by opportunistic pathogens. The document discusses various HAIs like bloodstream infections, pneumonia, surgical site infections, and diarrhoea. It outlines the common causative pathogens for each infection. A group of pathogens called ESKAPE pathogens are frequently antibiotic-resistant and include Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species. The document provides details on each of the ESKAPE pathogens and risks factors for acquiring HAIs. Prevention of HAIs is key and includes practices like hand hygiene, prudent antibiotic use

1. Healthcare Associated Infections and ESKAPE
Pathogens

2. 2
Human microbiome

3. Healthcare Associated Infections (nosocomial) are infections that are
acquired as a result of healthcare interventions. There are a number of
factors that can increase the risk of acquiring an infection, but high
standards of infection control practice minimise the risk of occurrence.
A pathogen is a micro-organism that has the potential to cause disease.
An infection is the invasion and multiplication of pathogenic microbes
in an individual or population. Disease is when the infection causes
damage to the individual’s vital functions or systems.
Definition
3

4. 4
Infections pattern

5. 5
Nosocomial infections - Infections that are acquired in
hospital (>48 hours after admission). They may occur even
after discharge. Approx 9% of patients affected – risk
increases with length of stay. Significant financial burden on
NHS
Nosocomial infections are often caused by opportunistic
pathogens, i.e. those which do not normally cause
infections in healthy people
Hospital microorganisms tend to be generally more
resistant to antbiotics and are therefore much harder to
treat
Hospital micro-organisms

6. Organisms in Healthcare Settings and known
nosocomial infections:
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Acinetobacter baumannii
Burkholderia cepacia
Candida albicans
Clostridium difficile
Clostridium sordellii
Enterobacteriaceae (carbapenem-
resistance)
Gastroenteritis
Hepatitis
Pneumonia (Ventilator-associated)
HIV
Influenza
Klebsiella
Legionnaires' disease
Mycobacterium abscessus
Norovirus
Pseudomonas aeruginosa
Staphylococcus aureus (coag-)
Stenotrophomonas maltophilia
Tuberculosis (TB)
Urinary tract infection
Enterococci
Extended Spectrum Beta-lactamase
producing organisms (ESBL+)
Vancomycin Resistant Staphylococcus
aureus (VRSA)
Vancomycin Resistant Enterococci (VRE)
pneumonia
Methicillin Resistant Staphylococcus
aureus (MRSA)
Acinetobacter spp

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Bloodstream infection (BSI)
Hospital-acquired pneumonia (HAP)
Surgical site infection (SSI)
Urinary tract infection (UTI)
Hospital-acquired diarrhoea
Most common nosocomial infections
Mortality

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35% Staphylococci (coagulase-negative)
25% Staphylococcus aureus
11.2% Enterococci
9.7% Fungi
6.2% Enterobacter spp
4.9% Pseudomonas spp
Bloodstream infections (BSI)
Common pathogens

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Peripheral intravenous line
and Central venous catheter
(CVC)
43% of all BSI are central line
(CVC) related!

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Ventilator-associated pneumonia
Normal chest x-ray Ventilator-associated pneumonia

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Pneumonia - Infections of the respiratory tract
Ventilator

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Risk factors old age,
antibiotic therapy,
immunosuppression,
chemotherapy and
others
Diarrhoea
Clostridium difficile

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20% Staphylococcus aureus
16% Pseudomonas spp
15% Staphylococci (coagulase-negative)
<10% Enterococcus spp
<10% Escherichia coli
<10% Enterobacter spp
<10% Fungi
Surgical site infections
Virulence
Bacterial dose
Impaired
host resistance
Pathogenesis

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50% Gram-negative coliforms
25% Fungi
10% Enterococci
Urinary Tract Infections (UTI)
Common pathogens

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Transmission of microorganisms
Contact – most common
• Direct (physical contact)
• Indirect (via contaminated objects)
Airborne Transmission
• Respiratory droplets
• Inhalation of infectious particles
Blood-borne transmission
Food-borne

16. ESKAPE Pathogens
Bacterial species from the ESKAPE group (i.e. E.faecium , Staphylococcus
aureus , Klebsiella pneumoniae , Acinetobacter baumannii ,
Pseudomonas aeruginosa and Enterobacter species) are frequently
resistant to antibiotics. "In many respects it’s far worse than MRSA,"
Antimicrobial resistance among both Gram-positive and Gram-negative
bacteria has been on the rise in the past few years. The presence of
multidrug-resistant (MDR) pathogens has become a cause for serious
concern with regard to nosocomial infections. The most common and
threatening MDR pathogens have been grouped together under the
acronym ‘ESKAPE,’ which stands for E.faecium, Staphylococcus aureus,
Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa
and Enterobacter spp.
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Risk Factors Patient risk factors
Environmental risk factors
Hospital micro-organisms
Antibiotics
Operative risk factors

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Patient risk factors
• Very old or very young
• Immunocompromised (HIV+, cancer,
chemotherapy, diabetes, alcoholism)
• Surgery
• Impaired local blood supply (peripheral vascular
disease)
• Medical devices (urinary catheters, intravascular
catheters, prosthetic joints or heart valves, endotracheal
tubes etc)
• Pre- and Pos-toperative issues
• Malnutrition

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• Contaminated air-conditioning systems (Ventilation )
• Contaminated water systems
• Staffing and physical layout of the facility (eg, nurse-
to-patient ratio, open beds close together)
• Operating room environment
• Surgical attire and drapes
• Asepsis and surgical technique
• Conventional sterilization of surgical instruments
Environmental risk factors

20. Multiple drug resistance (MDR)
Multiresistance is a condition enabling disease-causing
microrganisms (bacteria, viruses, fungi or parasites) to
resist distinct antimicrobials, first and
foremost antibiotics,but also antifungal drugs, antiviral
medications, antiparasitic drugs, chemicals of a wide
variety[1] of structure and function targeted at eradicating
the organism.
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21. Bacterial resistance
Various microorganisms
have
survived for thousands of
years
by their ability to adapt
to antimicrobial agents. They
do so via spontaneous
mutation or by DNA transfer.
This process enables some
bacteria to oppose the
action of
certain antibiotics, rendering
the antibiotics ineffective.
21

22.  No longer relying on a
glycoprotein cell wall
 Enzymatic deactivation of
antibiotics
 Decreased cell wall permeability
to antibiotics
 Altered target sites of antibiotic
 Moving of toxic substances
and antibiotics out of the cell[5]
 Increased mutation rate as a
stress response[6]
Several mechanisms in attaining
multi-drug resistance:
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23. Some resistant bacteria are able to
transfer copies of DNA that code
for a mechanism of resistance to
other nearby species of bacteria,
thereby conferring resistance to
their neighbours, which then are
also able to pass on the resistant
gene. This process is
called horizontal gene transfer.
Several mechanisms in attaining multi-drug resistance cont.
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24. Antifungal resistance:
(Candida species, Scedosporium prolificans )
Antiparasitic resistance:
(Plasmodium vivax , Toxoplasma gondii, Plasmodium falciparum)
Antiviral resistance:
(HIV, Influenza virus, Cytomegalovirus, Herpes simplex virus)
Other kind of resistance
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25. Enterococci are part of the normal
intestinal flora of humans and animals
but are also important pathogens
responsible for serious infections.
E.faecalis and E.faecium are the most
prevalent species cultured from
humans, accounting for more than
90% of clinical isolates. Other
enterococcal species known to cause
human infection include E. avium, E.
gallinarum, E.casseliflavus, E.durans,
E.raffinosus and E.mundtii.[1] E faecium
represents most vancomycin-resistant
enterococci (VRE). Infections include
urinary tract infections, most intra-
abdominal infections, and
uncomplicated wound infections.
ESKAPE group
Enterococcus species
25

26. MRSA is a type of staph bacteria that is
resistant to certain antibiotics called
beta-lactams. These antibiotics include
methicillin and other more common
antibiotics such as oxacillin, penicillin,
and amoxicillin. MRSA infections are
skin infections. More severe or
potentially life-threatening MRSA
infections occur most frequently among
patients in Healthcare Settings.
S. aureus is a bacterium commonly
found on the skin and in the nose of
about 30% of individuals. Most of the
time, staph does not cause any harm.
These infections can look like pimples,
boils, or other skin conditions and most
are able to be treated.
Methicillin-resistant Staphylococcus
aureus (MRSA)
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27. Klebsiella is a type of Gram (-)
bacteria that can cause healthcare-
associated infections including
pneumonia, bloodstream infections,
wound or surgical site infections, and
meningitis. Increasingly, Klebsiella bacteria
have developed antimicrobial resistance,
most recently to the class of antibiotics
known as carbapenems. Klebsiella bacteria
are normally found in the human
intestines (where they do not cause
disease). They are also found in human
stool (feces). In healthcare
settings, Klebsiella infections commonly
occur among sick patients who are
receiving treatment for other conditions.
Patients who have devices like ventilators
(breathing machines) or intravenous (vein)
catheters, and patients who are taking
long courses of certain antibiotics are
most at risk for infections.
Klebsiella pneumoniae
27

28. Acinetobacter baumannii A. baumannii infection is responsible for
a wide range of infections, including:
pneumonia, bacteraemia, meningitis,
wound infections, urinary tract
infections.
Acinetobacter is a group of bacteria
commonly found in soil and water.
Outbreaks of Acinetobacter infections
typically occur in intensive care units
and healthcare settings housing very ill
patients. While there are many types or
“species” of Acinetobacter and all can
cause human
disease, A.baumannii accounts for
about 80% of reported infections.
28

29. Pseudomonas aeruginosa
Pseudomonas infection is caused by strains
of bacteria found widely in the
environment; the most common type
causing infections in humans is called P.
aeruginosa. Serious Pseudomonas
infections usually occur in people in the
hospital and/or with weakened immune
systems. Pseudomonal infections can
involve the following parts of the body,
with corresponding symptoms and signs:
Pneumonia, Bacteremia, Endocarditis,
Meningitis, brain abscess, Otitis, Keratitis,
endophthalmitis,Osteomyelitis,Diarrhea,
enteritis, enterocolitis,Urinary tract, Skin
(eg, ecthyma gangrenosum)
29

30. Enterobacter species
Enterobacter infections can include
bacteremia, lower respiratory tract
infections, skin and soft-tissue
infections, urinary tract
infections (UTIs), endocarditis, intra-
abdominal infections, septic arthritis,
osteomyelitis, CNS infections, and
ophthalmic infections.
Enterobacter species are rod-shaped
bacteria that are found in the
environment and also in the human
intestinal tract. Some species are
pathogenic, the most common being E.
cloacae and E. aerogenes, which can
cause opportunistic infections in
immunocompromised patients.
30

31. To limit the development of antimicrobial resistance, it has been
suggested to:
 Use the appropriate antimicrobial for an infection; e.g. no
antibiotics for viral infections
 Identify the causative organism whenever possible
 Select an antimicrobial which targets the specific organism, rather
than relying on a broad-spectrum antimicrobial
 Complete an appropriate duration of antimicrobial treatment (not
too short and not too long)
 Use the correct dose for eradication; subtherapeutic dosing is
associated with resistance, as demonstrated in food animals
Preventing the emergence of antimicrobial
resistance
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Prevention of nosocomial infections
Hand washing

33. 33
Prudent use of antibiotics
Isolation & barrier precautions
Decontamination of equipment
Decontamination of environment
Prevention of nosocomial infections
Transparent dressings allow easy monitoring
of wound infection

34. Infection prevention is the most efficient strategy of
prevention of an infection with a MDR organism within a
hospital, because there are few alternatives to antibiotics in the
case of an extensively resistant or panresistant infection; if an
infection is localized, removal or excision can be attempted
(with MDR-TB the lung for example), but in the case of a
systemic infection only generic measures like boosting the
immune system with immunoglobulins may be possible. The
use of bacteriophages (viruses which kill bacteria) has no
clinical application at the present time.
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Prevention of nosocomial infections

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Chlorhexidine - Skin disinfection – Gram positive Gram
negative – moderate, some viruses, fungi
Ethanol – Skin disinfection - 70% (90% for viruses)
Isopropanol – Skin disinfection - 60-70%
Iodine and Iodophors - Skin disinfection - Broad spectrum
Sporicidal
Chloroxylenois - Cuts and abrasions - Gram positive
Hypochlorite solution - Environmental applications- Gram
positive Gram negative, AFB – moderate, bacterial spores,
fungi-moderate
Hydrogen peroxide gas - Environmental applications- Gram
positive Gram negative, AFB , bacterial spores, fungi, viruses
Choice of Disinfectants