Nosocomial infections, also known as healthcare-associated infections (HAIs), develop in patients during or after a hospital stay. Common types include central line-associated bloodstream infections, catheter-associated urinary tract infections, surgical site infections, and ventilator-associated pneumonia. Nosocomial infections can arise from a patient's own microbes or microbes transmitted from other patients, staff, or the hospital environment. Globally, nosocomial infections affect a huge number of patients annually, increasing mortality and costs significantly. According to WHO estimates, approximately 15% of hospitalized patients suffer from these infections.

1. Nosocomial infection
Presentation
by
Marwa A. Al-Asady

2. Nosocomial infection
 Nosocomial or ‘ healthcare associated infections’ (HCAI) is Infection
developing in patients after admission to the hospital, which was neither
present nor in the incubation period at the time of hospitalization. They may
become evident during patient’s stay or after their discharge.
 Additionally, they comprise occupational infections among the medical staff.
 Invasive devices such as catheters and ventilators employed in modern
health care are associated to these infections.
Marwa A. Al-Asady

3. Types of nosocomial infections
 Central line-associated bloodstream infections.
 Catheter associated urinary tract infections.
 Surgical site infections.
 Ventilator associated pneumonia.
 Other infection e.g. skin and soft tissue infection
Marwa A. Al-Asady

4. Sources of Infection
 Endogenous:- Patients own flora may invade, patient’s tissue during
some surgical operations or instrumental manipulations, normal
commensals of the skin, respiratory, GI.
 Exogenous:- From another patient / staff member / environment in
the hospital/ Environmental sources: Inanimate objects, air, water,
food/ Cross infection from: other patients, hospital staff (suffering
from infections or asymptomatic carriers)
Marwa A. Al-Asady

5. Nosocomial pathogens
 Any pathogen , on occasion, can cause HAI. Those that are able to survive
in hospital environment & develop resistance to antibiotics & disinfectants.
 Pathogens responsible for nosocomial infections are bacteria, viruses and
fungal parasites. These microorganisms vary depending upon different
patient populations, medical facilities and even difference in the
environment in which the care is given.
Marwa A. Al-Asady

6. Epidemiology of nosocomial infections
 Nosocomial infection affects huge number of patients globally, elevating
mortality rate and financial losses significantly.
 According to estimate reported of WHO, approximately 15% of all
hospitalized patients suffer from these infections.
 The incidence is high enough in high income countries i.e. between
3.5% and 12% whereas it varies between 5.7% and 19.1% in middle and
low income countries.
Marwa A. Al-Asady

7. Modes of Transmission
 1. Contact: Most common route of transmission
• Hands or Clothing:
- Hands of staff: important vehicle of spread
- Contact of hands & clothing of attendants
- e.g.: Staphylococcus aureus, Streptococcus pyrogenes
• Inanimate objects:
-Improper disinfection of Instruments: endoscope, bronchoscope, cystoscopy
e.g.: Pseudomonas aeruginosa
Marwa A. Al-Asady

8.  2. Airborne:
• Droplets:
- Droplets of Respiratory infections: transmitted by inhalation
• Dust:
- Dust from bedding, floors, wound exudates & skin
- e.g. : Pseudomonas aeruginosa, Staphylococcus aureus
• Aerosols:
- Aerosols from nebulizers, humidifiers.
e.g.: Legionella pneumophila
Marwa A. Al-Asady

9.  3. Oral Route:
- Hospital food may contain Antibiotic-resistant bacteria → may colonize
intestine → can cause infections
 4. Parenteral route:
- Disposable syringes & needles
- Certain infections may be transmitted by blood transfusion, tissue
contaminated blood products
e.g. : Hepatitis B, HIV
Marwa A. Al-Asady

10. References
 Ahmed Khan. H, Kanwal Baig, F., and Mehboob, R. (2017). Nosocomial
infections: Epidemiology, prevention, control and surveillance. Asian Pacific
Journal of Tropical Biomedicine. 1-5.
 WHO. The burden of health care-associated infection worldwide. 2016
[Online] Available from: http://www.who.int/gpsc/country_ work/burden
hcaien/ [Accessed on 10th August, 2016].
 Nejad SB, Syed SB, Ellis B, Pittet D. (2011). Health-care-associated infection in
Africa: a systematic review. Bull World Health Org. 89: 757-65
Marwa A. Al-Asady