Hospital-Acquired Infections: Causes, Agents, and Prevention

Hospital-Acquired Infections: Causes, Agents, and Prevention

A hospital-acquired infection (HAI) is an infection that a patient gets while receiving treatment in a hospital, excluding infections that were present before admission.

Characteristics:

• Exclusions: Infections that were present or incubating upon admission.

• Not HAIs: Infections that appear within the first 48 hours after admission.

• Possible HAIs: Infections that were not present at admission but appear after discharge.

High-Risk Groups:

• Individuals with compromised immune systems:

• Patients with immune system diseases.

• Patients using immunosuppressant drugs.

• People undergoing invasive procedures, extensive burns.

• Elderly patients with long-term hospitalization or malnourished children.

• Healthcare workers who frequently interact with infectious diseases.

Agents of HAIs:

• Bacteria:

• Gram-positive bacteria: commonly Staphylococcus aureus (Staph).

• Gram-negative bacteria: commonly found in HAIs, mainly gut bacteria such as Escherichia coli (E. coli), Klebsiella, Enterobacter.

• Pseudomonas aeruginosa (Pseudomonas): often found in HAIs.

• Viruses:

• Viruses that can cause HAIs: hepatitis A, B, C, HIV, influenza, measles, chickenpox, Rotavirus…

• Parasites:

• Candida albicans (yeast), Entamoeba histolytica (amoebic dysentery).

Characteristics of Bacteria Causing HAIs:

• They are often resistant to multiple antibiotics due to selective pressure in hospital environments.

Why are Staph, E.coli, and Pseudomonas commonly found in HAIs?

• High resistance, multidrug resistance to antibiotics.

• Present in various areas within the hospital.

Hospital Environment:

• Highly influential on HAIs.

• The interaction between the host, microorganisms, and the hospital environment plays a crucial role in determining the rate of HAIs.

HAI Cycle:

• Agent -> Reservoir -> Portal of Exit -> Mode of Transmission -> Portal of Entry -> Host Susceptibility -> Agent

Components of the Cycle:

• Agent: Bacteria, viruses, or parasites causing infection.

• Reservoir: Patients, carriers, contaminated equipment and objects, individuals who have recovered.

• Portal of Exit: Where the pathogen leaves the reservoir (respiratory tract, gastrointestinal tract, blood…).

• Mode of Transmission:

• Direct transmission: Through contact.

• Indirect transmission: Through contaminated machines, equipment, unsterilized tools, contaminated hands…

• Portal of Entry: The way microorganisms enter the body (e.g., respiratory tract, gastrointestinal tract, blood).

• Host Susceptibility: Depends on the body’s immune system.

Clinical Presentations of HAIs:

• Account for 5-7% of hospitalized patients.

• Common types:

• Urinary tract infections (due to catheterization).

• Surgical site infections, burn wound infections.

• Bronchopulmonary infections.

• Bacteremia (due to intravenous catheterization).

HAI Prevention Measures:

• Strictly adhere to aseptic techniques.

• Wash hands frequently.

• Isolate patients.

• Use dedicated equipment for each patient.

• Manage waste in wards and hospitals.

• Clean wards daily and periodically.

Conclusion:

Hospital-acquired infections are a significant concern in healthcare and require collaborative efforts from the whole community for prevention. Stringent implementation of preventive measures is crucial to minimize the risk of infection and ensure patient safety.