A.39 Nosocomial Infections

Question 1

A.39 Nosocomial Infections

Answer 1

Nosocomial infections, also referred to as hospital-acquired infections, are infections that are newly contracted within a hospital setting. These infections can spread through healthcare workers, patients, and various medical procedures. The most frequent sites of infection include the bloodstream, lungs, urinary tract, and surgical wounds.

Question 2

A.39 Nosocomial Infections
Types of infections:

Answer 2

1. Surgical Site Infections:
* Most Common Pathogen: Staphylococcus aureus
* Other Pathogens: Staphylococcus epidermidis, Enterococcus, E. coli, Pseudomonas aeruginosa
2. Nosocomial Pneumonia:
* Most Common Pathogens: Staphylococcus aureus, Pseudomonas aeruginosa
* Other Pathogens: Enterobacteriaceae, Haemophilus influenzae, Streptococcus pneumoniae, MRSA, ESBL-producing Enterobacteriaceae, Acinetobacter baumannii
3. Nosocomial Urinary Tract Infections:
* Most Common Pathogen: Escherichia coli
* Other Pathogens: Klebsiella, Enterococcus, Proteus mirabilis, Pseudomonas aeruginosa
4. Bloodstream Infections:
* Most Common Pathogen: Coagulase-negative staphylococci (e.g., Staphylococcus epidermidis)
* Other Pathogens: Enterococcus species, Klebsiella pneumoniae

Question 3

A.39 Nosocomial Infections
Risk Factors for Nosocomial Infections

Answer 3

1. Age: Individuals over 70 years are at a higher risk of infection.
2. Prolonged Hospital Stays: Increased risk due to:
   Medical Staff Involvement: Insufficient disinfection of hands, clothing, and surfaces (e.g., equipment, furniture).
   Indoor Air Quality: Infections can be transmitted through droplets from infected patients or procedures (e.g., bronchoscopy).
3. Metabolic Diseases: Particularly diabetes mellitus (DM) and immunosuppression.
4. Prior Antibiotic Use: History of antibiotic treatment can affect susceptibility.
5. Iatrogenic Factors: Resulting from treatment or diagnostic procedures, including:
   Use of invasive instruments and foreign bodies (e.g., catheters, endotracheal tubes).
   Conditions necessitating numerous interventional procedures (e.g., shock, major trauma, acute renal failure, coma).
   Mechanical ventilation.

Question 4

A.39 Nosocomial Infections
Source of Infection Management:

Answer 4

Remove: Identify and eliminate the source of infection, such as catheters and IV lines, to prevent further complications.

Question 5

A.39 Nosocomial Infections
Treatment by Pathogen:

Answer 5

1. MRSA (Methicillin-resistant Staphylococcus aureus):
   * First-line Treatment:
   * Vancomycin
   * Linezolid
   * Daptomycin
   * Tigecycline
2. Vancomycin-resistant Enterococcus (VRE):
   * Linezolid
3. Gram-negative Infections:
   * ESBL Pathogens (Extended-spectrum β-lactamase):
   * MDRGN (Multidrug-resistant Gram-negative):
   * Carbapenems (first-line)
   * Other treatments based on susceptibility (e.g., colistin, meropenem, tigecycline)
4. Pseudomonas aeruginosa:
   * MDRGN:
   * Piperacillin + Tazobactam
   * Cefepime
   * Ceftazidime
   * If resistance persists, consider using at least two of the last-resort antibiotics (e.g., colistin, polymyxin E).