What is Hospital Acquired Infection and its Prevention Techniques?

 Meaning of Hospital Acquired Infection:

Hospital Acquired Infection (HAI) also called nosocomial infection can be defined as follows:

“An Infection acquired in hospital by a patient who was admitted for a reason other than that infection.”

“An Infection occurring in a patient in whom the infection was not present or incubating at the time of admission but present while the patients is in a hospital or healthcare facility.”

“Hospital associated infections are those that are acquired during hospital care, but those that are not present or incubating at the time of admission. Infections occurring more than 48 hours after admission are usually considered nosocomial.”

Classification of Hospital Acquired Infection:

                     

                     According to World Health Organization:

a.     Surgical Site Infection (SSI)

b.     Catheter Associated Urinary Tract Infections (CAUTI)

c.      Nosocomial Pneumonia

d.     Nosocomial Bacteraemia

e.     Other Nosocomial infections

According to Centre for Disease Control and Prevention:

a)     Central Line Associated Blood Stream Infections (CLABSI)

b)     Catheter Associated Urinary Tract Infections (CAUTI)

c)      Surgical Site Infection (SSI)

d)     Ventilator Associated Pneumonia (VAP)

Meaning of Surgical Site Infection (SSI):

This refer to infections that show evidence of purulent discharge around the surgical wound, the insertion site of the drain, or spreading cellulitis from the wound. The incidence of surgical site infections varies from 0.5 to 20% depending upon the type of surgical procedure and the underlying patient condition. They pose a significant risk and limit timely recovery and potential benefits of surgical procedures.  There is also is a considerable impact on hospital costs and post-operative length of stay (between 3 to 20 additional days).

Usually, the infection is acquired during the surgical procedure itself from exogenous sources (e.g. Air, Equipment, Dressing Material, Surgeons etc.).

Endogenous sources (e.g. Flora on the skin, within the operative site or rarely from the blood used during surgery). The infecting microorganisms could be many according to the type and location of surgical procedure and the antibiotics received by the patient.     

Common organisms causing SSIs:

Staph. aureus, E. coli, Klebsiella spp., Enterococcus faecalis, Pseudomonas spp., anaerobic bacteria such as Bacteroides spp.

Catheter Associated Urinary Tract Infections (CAUTI):

This is most common nosocomial infection and about 80% of the hospital acquired urinary infections are associated with the use of a bladder catheter. Though these infections cause less morbidity than the other nosocomial infections, occasionally they can lead to bacteraemia and death.

The microbiological criteria for detection of these infections are usually defined as a positive quantitative urine culture with ≥ 105 microorganisms/ml and 1 or 2 isolated microbial species.  Usually the causative bacteria arise from the gut flora, either normal (Escherichiacoli or Multi resistant Klebsiella).  

Common organisms causing UTI:

E. coli, Klebsiella spp., Proteus spp., Enterococci spp., Pseudomonas aeruginosa, Serratia marcescens, Candida spp., Staph. aureus, Staph. Epidermidis

Ventilator Associated Pneumonia (VAP):

Pneumonia is one of the most serious of HAIs. Ventilator-associated pneumonia (VAP) is the most important infection in patients on ventilators in intensive care units. It has a high case fatality rate and is often associated with serious comorbidities.

Healthcare-associated pneumonia is acquired by the inhalation of respiratory droplets or aerosols, or aspiration of colonized oropharyngeal and gastric secretions in conditions of low gastric acidity. Infection can also be acquired through the oropharynx during suction procedures, due to inadequate hand washing and inappropriate disinfection of respiratory devices.

Central Line Associated Blood Stream Infections (CLABSI):

These infections represent approximately 5% of nosocomial infections but have more than 50% case fatality rates for some microorganism. For some microorganisms, the incidence is increasing, such as multi drug resistant coagulase – negative staphylococcus and candida species.

Infection could be at the site of skin entry of intravascular device, or in the path of the catheter below skin, also called as tunnel infection. The source of infection is the resident or transient flora on the skin.

The risk of bacteraemia depends on the duration of catheterization, level of followed asepsis at the time of insertion, and the continuing catheter care followed.

Vascular access pose significant risk of development of catheter related blood stream infections (CRBSI).

Central line insertion is a very common procedure in critical care settings, is associated with local bacterial colonization, leading to bacteraemia and sepsis also known as central line associated blood stream infection (CLABSI).     

Diagnosis of such catheter related infection can be made by combination of clinical picture with quantitative culture techniques.

Common organisms causing bloodstream infections:

Escherichia coli, Enterococcus spp., Staphylococcus aureus, Klebsiella spp., Salmonella spp., Candida spp., Pseudomonas spp., Corynebacteria spp., Acinetobacter spp., Coagulase Negative Staphylococcus (CNS).

Prevention of Hospital Acquired Infection:

Hospital Acquired Infection can be prevented by breaking the epidemiological triad. The most effective way to prevent Hospital Acquired Infection is by introducing a barrier between the susceptible host and the infecting organism. Care bundles include a set of evidence-based measures that need to be implemented together, to show a significant improvement in patient care. Bundles need to be simple, clear and precise so that they can be followed easily and appropriately. Most Hospital Acquired Infection can be prevented through readily available and relatively inexpensive strategies such as compliance with recommended infection prevention practices such as:

1. Hand hygiene
2. Appropriate use of personal protective equipment 
3. Following aseptic techniques stringently
4. Use of Care Bundles
5. Paying attention to established practices for cleaning and decontamination of soiled instruments, followed by either sterilization or high-level disinfection
6. Appropriate disposal of biomedical waste 
7. Appropriate cleaning and disinfection of the environment
8. Maintaining a safe working environment and safe work practice 

Written by:

Dr. Praveen Bajpai

Director of Ingenious Healthcare Consultants Pvt. Ltd.
Founder of Skill Sathi

MBA in Hospital administration, PG Diploma in Quality Accreditation, PG Diploma in Medico Legal System, M. Phil in Hospital Mgmt. from BITS Pilani, P.hD in Management, Certified NABH Auditor, Certified NABL Auditor, Certified Auditor for Clinical Audits, Green Belt in Six Sigma, Certified in Hospital Infection Control Practices, Certified trainer for International Patient Safety Goals, Certified Auditor for JCI 7th Edition Standards 

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