Nosocomial Infection

Nosocomial Infection-Nosocomial infections known also as hospital-acquired infections, hospital-associated infections that are not present in the patient at the time of admission to hospital but develop during the course of the stay in hospital.

Meaning

Nesocomal infection comes from Greek words nosus meaning 'disease" and "komeion" meaning  "to take care of "Also called as Hospital Acquired Infection.

Definition

Nosocomial infections can be defined as infection acquired by the person in the hospital, manifestation of which may occur during hospitalization or after discharge from hospital. The person may be a patient, members of the hospital staff and visitors.

Epidemiology

  • Nosocomial infections can be exogenous (external organism) and endogenous (normal flora).
  • Host susceptibility is an important factor in the developments of nosocomial infection.
  • Medical equipments and procedures (surgery) are often responsible for infections.

Modes of Transmission 

There are five main modes of transmission.

  1. Droplet Transmission
  2. Vector borne Transmission
  3. Air borne Transmission
  4. Common vehicle Transmission
  5. Contact Transmission

1. Droplet Transmission
Droplet generated by sneezing, Coughing or respiratory tract procedures, like Broncoscopy or suction

2. Vector Transmission-Transmitted through insects and Other invertebrates animals such as mosquitoes and fleas. 
3. Air Borne Transmission-Tiny droplet nuclei that remain (<5) suspended in air.

4. Common Vehicle Transmission-Transmitted indirectly by materials contaminated with the infections. 

5. Contact Transmission -Most important and frequent mode of transmission of nosocomial infections, is divided into two subgroups-

  • Direct-contact transmission
  • Indirect-contact transmission.
  1. Direct-contact transmission -Involves a direct body surface-to-body surface contact and physical transfer of microorganisms between a susceptible host and an infected or colonized person, such as occurs when a person turns a patient, gives a patient a bath. 
  2. Indirect-contact transmission -Involves contact of a susceptible host with a contaminated intermediate object, usually inanimate, such as contaminated instruments, needles , or dressings, or contaminated gloves that are not changed between patients.  

 Sites of Nosocomial Infection with their incidence

 Average Incidence - 5% to 10%, but maybe up to 28% in ICU

1. Urinary Tract Infection - Usually catheter related -28%

2. Surgical Site Infection or wound infection - 19%

3. Pneumonia -17%

4. Blood Stream infection - 7% to 16%

5. Others – GIT, CNS- 10 to 20%

Prevention and Control of Nosocomial Infection-

A. Prevention

  • Administration of antibiotic therapy to the carrier staff or source patients to destroy the pathogenic agents
  • Proper sterilization and disinfection of inanimate objects. This helps to control the source of infection.
  • Disinfection of excreta and infected material is necessary to control the exit point of infection.
  • Transmission can be controlled by regular washing of hands, disinfection of equipments and change of working clothes.
  • Use of sterile dressings, surgical gloves and face masks further contribute in control of nosocomial infection.
  • Post operative disinfection of patient's skin.
  • Proper investigation of HAI and treatment of such cases.

B. Hospital Infection Control

  • Reduce patient exposure to pathogens.
  • Reduce the number and virulence of nosocomial pathogens.
  • Use of aseptic technique during patient care.
  • Place use sharps in puncture resistant containers.
  • Ensure clean environment.
  • Establish a regular schedule of hospital cleaning with appropriate disinfectants in for Example-Ward, Operation theatre and laundry.
  • Dispose the medical waste safely.
  • Hand washing after and before any procedure.
  • Proper isolation of patients known or suspected harbouring infectious disease.
  • Whenever possible, avoid crowding wards.
  • Use gloves when necessary.
  • Wash hands immediately after glove removal and between patients.
  • Masks, Eye protection, Gown wear during activities likely to generate sprays.
  • Avoid recapping of needles.
  • Avoid removing needles from syringes by hand.
  • Needles and Syringes should be incinerated.
  • Other infected waste can be incinerated or autoclaved for landfill disposal.

Standard Safety Measures to Minimise the Infections-

  • All blood specimens or body fluids must be placed in leak-proof impervious bags for transportation to the laboratory.
  • Assume that all specimen patients are potentially infectious for pathogens.
  • Use gloves while handling blood and body fluid specimens and other objects exposed to them. 
  • If there are chances of spattering, use face masks and glasses.
  • Wear laboratory coat or gowns while working in the laboratory. These should not be taken outside,
  • Never pipette by mouth. Mechanical pipetting devices should be used.
  • Biological safety hoods should be used for laboratory work.
  • All potentially contaminated materials of laboratory should be decontaminated before disposal or reprocessing.
  • Decontaminate laboratory work surfaces with appropriate disinfectant after the spillage of blood other body fluids.
  • Limit use of needles and syringes to situations for which there are no other alternatives.
  • Always wash hands.
  • Remove all protective clothing before leaving the laboratory.
     

 

 

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