Learning Objectives

• Define Nosocomial infection, Health care associated infection

• What are the common Nosocomial infections?

• What is the mode of transmission?

HAI / HCAI

• What are the common organisms involved?

• Prevention of Health care associated infections

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 Terminologies
• Nosocomial Infection

• Hospital acquired infection (HAI)

• Health care associated infection (HCAI)

HAI / HCAI

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 Definition
• Hospital acquired infection is a localized or systemic condition resulting from an
adverse reaction to the presence of an infectious agent(s) or its toxin(s) which was
not present or incubating at the time of admission to hospital.

• Usually the infection becomes evident 48 hours or more after admission.

HAI / HCAI

• Health care associated infections: Infections acquired in institutions other than

acute-care facilities (e.g. nursing homes) during hospitalization but not identified
until after discharge and through outpatient care such as day surgery, dialysis, or
those on home parenteral therapy
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 Common Sites
1. Respiratory tract – HAP

2. Blood stream infection (BSI) – CABSI/CRBSI

3. Urinary tract - CAUTI

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4. Surgical site infection (SSI)

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 The Burden
• The worldwide nosocomial infection rate ranges from 6% to 15%

• In Asia it ranges from 4% to 48% of which 45% to 65% are lower respiratory tract
infections
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• Highest prevalence → intensive care units (ICUs), in acute surgical and orthopaedic
wards.

• Organisms →Pseudomonas spp, Acinetobacter spp, S. aureus, methicillin-resistant

S. aureus (MRSA), Enterobacteriaceae, Candida spp, Enterococci and
Stenotrophomonas

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 Common Sources of Infection
• Intrinsic : Causative organisms may be present on the skin, nose, mouth,
gastrointestinal tract, or vagina of the patient

• Extrinsic : They may be acquired from external sources like health care personnel,
visitors, hospital equipments, medical devices, or the health care environment.
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• Etiology :

• Most infections → bacterial aetiology

• fungal and viral infections → immunosuppressed patients and those already on

broad-spectrum antibiotics.

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 Case Scenario
• A 40 year old male is admitted to the ICU with history of head injury. Patient had a
GCS of 6/15 and hence was put on mechanical ventilation. His initial chest xray is in
the following image. On day 5 after admission he develops fever, purulent secretions
in endotracheal aspirate and total WBC count is 15,000. What is the likely diagnosis
HAI / HCAI

and how will you manage?

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HAI / HCAI
 Modes of Transmission
• Cross-infection via unclean hands of hospital personnel

• Auto-inoculation (eg. Aspiration)

• Droplet infection
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• Through contaminated materials (eg. Contaminated intravenous fluids).

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 Hospital Acquired Pneumonia (Hap)
• Definition HAP : Pneumonia occurring 48 hours or more after admission and which
was not incubating at the time of admission.

• Intubation and mechanical ventilation (MV) is associated with 20-fold increase in the
risk of developing pneumonia.
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• Ventilator associated pneumonia (VAP) is pneumonia in a person who has a device

to assist respiration through an endotracheal tube or tracheostomy tube for a period
of at least 48 hours before the onset of infection. VAP represents 80% of episodes of
HAP

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 HCAP
• Health care associated pneumonia (HCAP) is defined as pneumonia in any patient
with at least one of the following risk factors:

1. Hospitalisation in an acute care hospital for >2 days within the last 90 days.
HAI / HCAI

2. Residence in a nursing home or long-term care facility within the last 90 days

3. Received outpatient intravenous antibiotics or chemotherapy or home wound care

in last 30 days.

4. Attended a hospital clinic or haemodialysis clinic in the last 30 days

5. Has a family member with known multi-drug resistant pathogens

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 Causative Organisms
• HCAP may be early onset →within 4 days of hospitalisation or late onset → beyond
4 days.

• The organisms causing early infections are Moraxella catarrhalis, Haemophilus

influenzae and S. pneumoniae; whereas Gram-negative bacteria or S. aureus are
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associated with the late HCAP.

• Viruses may cause early and late infections while yeasts, fungi, Legionella and
Pneumocystis carinii are typically late pathogens

• Late onset pathogens often are multi-drug resistant (MDR)

• Over 80% of nosocomial pneumonias are caused by Gram-negative bacteria. Now

12 Acinetobacter is the organism which is of great concern
 Causative Organisms
• In India, 38% of HAP are caused by Acinetobacter, Pseudomonas spp (20%),
Klebsiella pneumoniae (23%) and MRSA (5%).
HAI / HCAI

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 Risk Factors for MDR Infections
• Regular dialysis

• Immunosuppression

• Heart disease
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• Renal failure

• Hepatic failure

• High incidence of antibiotic resistance in the community

• Presence of a family member with MDR organism

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 Risk Factors for HAP and VAP
• Males • Mechanical ventilation

• Elderly age • Supine position

• APACHE II score >15
• Pre-existing diseases—pulmonary,
• Previous use of antibiotic for >2 weeks
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diabetes, dialysis
• Multi-organ failure
• Immunosuppression
• Reintubation due to failed weaning
• Presence of intubation • Use of paralytics, sedative

• Enteral feeding • Length of ICU stay

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 Diagnosis
Diagnosis of HCAP or VAP is made in the presence of

1. Progressive radiographic infiltrates or pleural effusion

2. and at least 2 of the 4 clinical signs of infection

HAI / HCAI

• fever >38°C
• purulent secretions

• leucocytosis or leucopaenia

• decreasing oxygenation

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HAI / HCAI VAP
 Management
1. Identification of pulmonary infection is the first step

2. Appropriate cultures are required - Endotracheal aspirates, bronchoalveolar lavage

(BAL)
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3. A broad-spectrum antibiotic should be started at the earliest in all clinically unstable

patients regardless of culture reports as delay is associated with increased mortality

Once culture-sensitivity reports are available de-escalation may be done

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 Blood Stream Infection (BSI)
• Primary blood stream infections are identified by growth of pathogenic bacteria or
fungi (that are not related to another site of infection) from one or more blood
cultures.

• Skin contaminants like coagulase negative Staphylococcus or Diphtheroids are

HAI / HCAI

considered causative of BSI, if more than one blood culture is positive along with
presence of systemic signs and symptoms of infection like fever, chills, and
hypotension. An alternative focus of infection should be absent

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 BSI - Catheter
• Catheter associated blood stream infections (CABSI) is said to be present if fever
occurs during and up to 48 hours after removal of central venous catheter or arterial
catheter but diagnosis does not require growth of same organism from the blood
and the catheter
HAI / HCAI

• Catheter related blood stream infection (CRBSI) Diagnosis of CRBSI requires growth
of same organism quantitative or semiquantitative from the blood as well as the
catheter.

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HAI / HCAI Central Catheters

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 Diagnosis
• BSI are identified by the growth of pathogenic bacteria or fungi (that are not related
to another site of infection) from one or more blood cultures drawn from peripheral
veins. At least two sets of blood cultures must be drawn in each instance

• CRBSI - The best method is to obtain paired blood cultures, one from the central
HAI / HCAI

catheter and another from the peripheral venous blood and the differential time to
culture positivity is noted. If central line sample shows positivity 2 hours earlier than
the peripheral culture, it is a CRBSI.

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 Management
• Catheter should be removed if CRBSI is suspected, if there is purulence at the
insertion site or the patient is haemodynamically unstable, has organ dysfunction,
fungal sepsis or MDR organisms and once the diagnosis is confirmed.

• Empirical antibiotics should be started in seriously ill patients

HAI / HCAI

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 Surgical Site Infection (SSI)
• Incisional surgical site infections (SSIs) → superficial or deep.

• Superficial SSIs involve skin and subcutaneous tissue of the incision and at least one
of the following: (a) purulent drainage; (b) isolation of organism from the site; (c) at
least one of the clinical findings of tenderness, redness or heat on the incision line;
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or (d) diagnosis made by the surgeon or attending physician.

• Deep SSI is defined as infection involving fascia or muscle layers of or intentional

opening by surgeon in a patient with fever, local pain, tenderness, abscess or
diagnosis by physician.

• Superficial SSI occurs within 30 days of surgery. Deep SSI occurs within 30 days of
24 surgery if no implant is left in place or within one year in presence of implant.
 Surgical Site Infection (SSI)
• In India, incidence of post-operative infections in hospitals varies from 10% to 25%
HAI / HCAI

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HAI / HCAI SSI
 Diagnosis and Management
• Signs of wound infection are local redness, swelling, wound discharge, fever and in
severe cases shock and organ dysfunction. Appropriate cultures from wound, drain
and blood should be sent and empirical antibiotics started

• Prevention of SSI
HAI / HCAI

✓Treating infections harboured by the host before surgery

✓Good antiseptic precautions

✓Antibiotic prophylaxis within 1 hour of surgery

✓Hair clipping rather removal

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✓Optimum post-operative care including good glycemic control
 Urinary Tract Infections (UTI)
• UTIs in hospital are mostly due to urological manipulation or the presence of
indwelling catheters.

• Risk for UTI is high in females, diabetics, the elderly, in the peripartum period and is
proportional to the duration of catheterisation
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 CAUTI
• A diagnosis of CAUTIs : patient with a urinary catheter has one or more of the
following symptoms with no other recognized cause: fever (temperature >38°C),
urgency or suprapubic tenderness with a culture-positive urine showing more than
10^5 colony-forming units per ml
HAI / HCAI

• Commonest isolated pathogen is E. coli, others include Enterococci, Pseudomonas,

Klebsiella, Enterobacter, S. epidermidis, S. aureus, and Serratia

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HAI / HCAI CAUTI
 Prevention And Treatment
• To prevent UTIs, indwelling catheters are to be used only when necessary, sterile
techniques are to be used during catheterisation, closed system of drainage is to be
used, samples must be taken aseptically and irrigation is to be avoided.

• Asymptomatic bacteriuria in catheterised patients is not to be treated

HAI / HCAI

• Removal of catheter and broad spectrum antibiotics till culture sensitivity

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 Other HAI
• TRACHEOBRONCHITIS

• SINUSITIS

• CLOSTRIDIUM DIFFICILE ASSOCIATED DIARRHOEA (CDAD)

HAI / HCAI

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 Prevention And Control Of
Nosocomial Infections
• A hospital infection control committee comprising of a senior microbiologist,
intensivist, physician and surgeon is essential to prevent and control HAI.

• Periodic surveillance of infections is important.

HAI / HCAI

• Microorganisms, sensitivity patterns, antibiotic use, outcomes, all must be audited.

• Antibiotic policy should be formulated and revised regularly for effective therapy

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 Strategies To Be Adopted To Combat
HCAI
1. Environmental factors:

➢Adequate bed-space ratio

➢Identifying infected zones

➢Proper disposal of biomedical wastes in protocol containers
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➢Ensure food hygiene

➢Routine checking of potable, dialysis water

➢Ventilation strategies for operating theatres, isolation areas for infected or

immunocompromised cases

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 Specific Strategies
2. Specific standard precautions for all patients in health care settings as
recommended by Centers for Disease Control and Prevention:

➢Hand hygiene with alcohol based hand rubs is to be performed after examining each
patient, before and after every procedure or handling patient’s body fluids. In
HAI / HCAI

suspected C. difficile infection hands are to be washed with soap and water.

➢Respiratory and cough etiquettes are to be followed.

➢Mask, eye protection or face shield is to be worn for procedures which might involve
splashes.

➢N95 or higher masks for diseases transmitted by respiratory aerosols like

35 tuberculosis, some viruses
 Specific Strategies
➢Gloves are to be used where recommended. Masks and gowns are to be worn while
handling patients infected with Acinetobacter, MRSA or MDR pathogens.

➢Appropriate handling of soiled linen and equipment and disinfection of

environmental surfaces.
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➢Used needles are not to be bent, broken by hand or recapped.

➢For patient resuscitation, a mouthpiece, resuscitation bag are needed to prevent

contact with oral secretions.

➢For injected medications, single dose vials are preferable to multiple dose vials

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