Hospital Acquired Infections Question And Answers

Hospital Acquired Infections

 

Question 1. Write a short note on nosocomial infections.
Answer:

Nosocomial infections are defined as infections developing in patients after admission to the hospital who were neither present nor in the incubation period at the time of hospitalization. Nosocomial infections are also known as hospital-acquired infections hospital-associated infections or healthcare-associated infections.

Microorganisms Leading to Nosocomial Infections

1. Bacteria

• Aerobic bacteria:
  • Staphylococcus aureus
  • Streptococcus pyogenes
  • E. coli
  • Klebsiella spp.
  • Porteus spp.
  • Staphylococcus epidermidis
  • Haemophilus spp.
  • Salmonella spp.
  • Shigella spp.
  • Pseudomonas aeruginosa
  • Mycobacterium spp.
  • Bacillus subtilis
• Anaerobic bacteria:
  • Bacteroides fragilis
  • Clostridium spp.
  • Anaerobic cocci

Read And Learn More: Microbiology Question And Answers

2. Viruses:

• Hepatitis A, B, C, and D
• Herpes simplex virus
• CytomegalovirusInflenza virus
• Rotavirus
• HIV

3. Fungi:

• Cryptococcus spp.
• Histoplasma spp.
• Mucor spp.
• Aspergillus spp.
• Candida spp.
• Pneumocystis carinii

4. Parasites:

• E. histolytica
• Toxoplasma gondii

Sources of Nosocomial Infections

Exogenous: Nosocomial infection is exogenous from other patients or members of staff or by the internal environment in the hospital. Exogenous infections are of two types, i.e. cross infection and environmental infection

• Cross infection: This type of infection occurs from another patient or the hospital staff, Here the infected patient or staff member transfers the infection to a susceptor- ble individual.
• Environmental infection: It occurs by inanimate objects, i.e. bedding and clothing, air, water, food, urinal, IV fluid equipment, dust, dry environment, etc.

Endogenous: In this type, the microorganisms present inside and outside the body surface of the patient act as opportunistic pathogens. These are also known as autoinfections or self-infections.

Transmission of Nosocomial Infections

• Contact: It is the principal route for transmission which occurs via the hands or clothing of hospital staff, It is also transmitted by the patient himself/herself. It is also transmitted by contact with inanimate objects.
• Airborne: This is transmitted via droplet infection, dust via bedding or floors, exudates dispersed from the wound during dressing, shedding of skin scales, aerosols produced by nebulizers or humidifiers, or air conditioning apparatus.
• Oral route: It occurs by contaminated food or water.
• Parenteral route: Infection spreads via the use of contaminated syringes and needles, administration of contaminated blood, and blood products.

Types of Nosocomial Infections

• Urinary tract infection: It is the most common nosocomial infection. It is associated with catheterization or instrumentation of the urinary tract. It is caused by E. coli, Klebsiella, P roteus, S erratia, Pseudomonas, Providencia, enterococci and candida albicans.
• Respiratory tract infection: It occurs because of aspiration in unconscious patient and pulmonary ventilation may cause nosocomial pneumonia. It is caused by S. aureus, Klebsiella spp., Enterobacter, Serratia, Proteus, E. coli, Pseudomonas aeruginosa, Acinetobacter, Legionella pneumophila, and respiratory viruses.
• Wound and soft tissue infections: Most of the wound infections occur under a week of surgery. S. aureus is a predominant pathogen followed by E. coli, Proteus, enterococci, and coagulase-negative staphylococci.
• Gastrointestinal infections: These occur by contaminated food as well as water. This occurs in the form of food poisoning and neonatal septicemia.
• Burns: Microorganisms such as Pseudomonas aeruginosa, Acinetobacter, and S. pyogenes lead to nosocomial infections in burns.

Laboratory Diagnosis

• Etiological diagnosis of nosocomial infections is made by routine diagnostic methods such as smear, culture, and identification.
• Antibiotic susceptibility testing is done due to multiple drug resistance in nosocomial pathogens.
• In outbreak situations, the source should be found by sampling possible sources, i.e. inanimate objects and hospital personnel along with patients who are susceptible to colonization. Water, food, air, blood products, transfusion fluids, disinfectants, etc. should be needed.
• Carries should be detected among staff and patients.
• Typing of isolates should be done from patients and hospital environments for detecting sources of infection. Typing methods indicated are biotyping, serotyping, bacteriocin typing, phage typing, etc.

Prevention of Nosocomial Infections

• Transmission of infection is controlled by proper handwashing, equipment disinfection, and changing of working clothes.
• Antibiotics should be given to carrier staff or source patients to destroy pathogens.
• Inanimate objects should be properly disinfected and sterilized.
• Disinfection of excreta and infected material is necessary.
• The use of sterile dressing, surgical gloves, facemasks, and IV fluids should be strictly recommended.
• The patient’s skin should be disinfected preoperatively.
• Overcrowding of patients should be avoided in the ward.
• Universal safety procedures should be strictly followed to control transmission routes.
• Rational antibiotic prophylaxis is recommended.
• Hospital-acquired infections should be properly investigated and treatment of such cases should be done.
• Vaccination should be given to protect susceptible hosts.