Nosocomial infection Hospital Infection

Hospital acquired infections Nosocomial infections are those that originate or occur in a hospital or hospital-like setting. Nosocomial infections are responsible for about 20,000 deaths in the U.S. per year. Approximately 10% of hospital patients acquire a clinically significant nosocomial infection.

Classification CAI → hospital admission (pneumonia) Admission → infection (device-associated bacteraemia) Discharge → infections (Surgical site infection) Infection to hospital staff (Hepatitis B infection)

Why hospital infections High prevalence of pathogens More compromised hosts Efficient mechanisms of transmission from patient to patient

Presence of pathogens Nosocomial infections are primarily caused by opportunists, particularly b: Enterococcus spp. Escherichia coli Pseudomonas spp. Staphylococcus aureus

Sites of nosocomial infections Most to least common: Urinary tract Surgical wounds Respiratory tract Skin (especially burns) Blood (bacteremia) Gastrointestinal tract Central nervous system

Hospital microorganisms tend to acquire antibiotic resistance factors

Normal microflora of HCW Pathogens become incorporated into the normal flora of hospital workers Nosocomial pathogens tend to be: Available for transmission to patients Not easily treated

Compromised hosts Infants and elderly Pre- existing diseases Immuno-suppressive Radio therapy or Chemo therapy Splenectomy Broken skin and mucous membranes Surgery, insertion of catheters, tracheostomy, ventilators, …etc.

Chain of transmission Many sick patients under one roof More efficient transmission

Modes of transmission Direct person-to-person transmission: Infected patient, staff member, or visitor Indirect transmission through: Equipment, supplies and hospital procedures Transmission through air

Routes of transmission Air-borne Contact spread (direct or indirect) Food-borne spread Blood-borne spread (injuries or transfusion) Self-infection and cross-infection

Prevention The infection control policy Staff training and education Cleaning, disinfection and sterilization Aseptic techniques Prophylactic antibiotics

Prevention Protective clothing Isolation of dangerous patients Hospital building and design Equipment Microbiology surveillance

Control measures to reduce exogenous hospital acquired infection Patient water Staff carries Equipment Domestic environment Air Infectious patients Food Staff contact