Hospital-acquired infections are caused by viral, bacterial, and fungal pathogens; the most common types are bloodstream infection (BSI), pneumonia (eg, ventilator-associated pneumonia [VAP]), urinary tract infection (UTI), and surgical site infection (SSI)

1. Hospital Acquired Infections
(Nosocomial Infections)
Dr. Aparna Sen Chaudhary

2. Definition
• “Nosos = Disease; Nosocomial = Relating to a Hospital
• Cross-infections occurring in hospitals.
• Infections acquired during hospital care which are not present or incubating at
admission.
• Infections occurring more than 48 hours after admission or may become clinically
evident after discharge.
• Infections acquired by patients, staff or visitors included
• Endemic/epidemic

3. Problem Statement
• Any time over 1.4 million people worldwide suffer from infectious complications
acquired in hospital.
• Prevalence of HAI
• 7-12% in Developed countries
• 25-40 % in India

4. Causes of HAI
• Failure to observe aseptic precautions
• Predisposing Factors
• Resistance by Organism
• Overcrowding in hospitals
• Poor environment
• Decreased resistance and increased susceptibility of vulnerable groups
• Etiological agents :
• 50 % - Staphylococci
• 45% - Gram negative Bacteria (E.coli , Klebsiella)
• 5% - Viruses, protozoa, fungi et

6. Simplified criteria for surveillance of HAIs
Type of Nosocomial infection Simplified Criteria
Surgical site infection Any purulent discharge, abscess, spreading cellulitis at the
site during the month after operation
Urinary Infection + urine culture – at least 105 bacteria/ml , with or without
symptoms
Respiratory Infection Respiratory symptoms with at least 2 signs appearing during
hospitalization –
• Cough
• Purulent sputum
• New infiltrate on chest radiograph
Vascular Catheter Infection Inflammation, lymphangitis, purulent discharge at the
insertion site of catheter
Septicemia Fever or rigors – at least 1 + blood culture

7. Epidemiological
Triad of HAI

8. Sources
• Sources are
1. Patients
• Viral Infections (measles, influenza, hepatitis)
• Skin Infections (discharging wounds, psoriasis, boils, infected skin lesions)
• Respiratory Tract infections
• Urinary Tract Infections
2. Staff
3. Environment

9. Routes of Spread
• Direct contact
• Droplet infection – coughing, sneezing
• Air borne particles
• Hospital dust
• Procedures – catheterization, IV procedures, dressings, sputum cups etc.

10. Recipients
• Severely ill
• Corticosteroid therapy
• ICU
• Urological wards
• Geriatric wards
• Special Baby care units

11. Preventive measures
1. Isolation
2. Hospital staff – sick workers away from
work
3. Hand washing
4. Dust control – wet dusting, vacuum
cleaning
5. Disinfection – urine, sputum, faeces–
sterilization of instrument
6. Control of droplet infection – face masks,
proper bed spacing, prevent over
crowding, adequate lighting &
ventilation
7. Nursing techniques – barrier & task
nursing
8. Administrative measures – “Infection
control committee”
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12. Standard precautions
• Limiting Healthcare worker contact with all secretions
or biological fluids , lesions, mucus membrane
• Wear Gloves for each contact which may lead to
contamination
• Wash hands promptly after contact with infective
material and after removing gloves
• All sharps should be handled with extreme care
• Clean up spills of infective material promptly

13. Standard precautions
• Sterilized linen b/w each patient use
• Appropriate waste handling
• Employees health reviewed at recruitment
• Immunization history
• Previous exposure to communicable diseases
• Immune status (e.g. varicella zoster- VZV)
• Immunization – Hep A & B, MMR, Diphtheria &
Tetanus.
• Mantoux test – for previous TB infection
• Specific post exposure policies – HIV, Hep A,B, C & E,
Neisseria meningitis, TB, VZV, Diphtheria, pertussis,
Rabies

14. Measures for prevention of infection
Infection Preventive measures Proven not effective
UTI • Limit duration of catheter
• Aseptic technique at insertion
• Maintain closed drainage
• Systemic antibiotic prophylaxis
Surgical site
infections
• Surgical technique
• Clean operating environment
• Limiting preoperative hospital
stay
• Preoperative skin preparation
• Optimal antibiotic prophylaxis
• Aseptic practice in operating
room
• Surgical wound surveillance
• Fumigation
• Preoperative Shaving
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15. Measures for prevention of infection
Infection Preventive measures Proven not effective
Pneumonia Ventilator Associated
• Aseptic intubation & suctioning
• Limit duration
• Non-invasive ventilation
Others
• Influenza vaccination (staff)
• Isolation policy
• Change of ventilator circuit
every 48 or 72 hours
Vascular device
infections
All catheters
• Closed system
• Limit duration
• Local skin preparation
• Aseptic technique
• Removal - infection suspected
Central lines
• Surgical asepsis
• Limitation of dressing change
• Antibiotic coated catheter
• Antimicrobial creams for skin
preparations
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16. Thank
you