23: Healthcare-acquired infections

Question 1

What are the most common HAIs?

Answer 1

1. Device-related infx
   
   1. UTC
   2. CVC
   3. Ventilator
2. Surgical site infx
   
   1. Wound
   2. Artificial joint
   3. Valve

Question 2

What are potential sources of pathogens in CVCs?

Answer 2

• Skin organisms
  
  • Enogenous skin flora
  • Extrinisc via HCW hands, contaminated disinfectant
• Contaminated catheter hub
• Contaminated infusate
• Hematogenous from distant infx

Question 3

For surgical site infections (SSIs):

1. Pathogenesis
2. Organisms
3. Diagnosis

Answer 3

1. Endogenous: patient skin, mucous membranes or viscera; exogenous: contact of wound w/ contaminated environment, personnel, air, surgical instruments; hematogenous/lymphatic source
2. S. aureus, GNs
3. Examine wound, culture

Question 4

For ventilator-associated pneumonia:

1. Pathogenesis
2. Organisms
3. Diagnosis

Answer 4

1. Biofilm, decr. mucous clearance, thwarted cough reflux, ETT = conduit from URT to LRT; organism dislodge during suctioning; microbial adherence (reduced mucosal IgA, incr. protease production, denuded mucous membraes, incr. bacterial receptors)
2. Normal = viridans, haemophilus, anaerobes; critically ill = aerobic GN, GP (s. aureus); Acinetobacter, P. aeruginosa, non-TB myco, B. cepacia, Legionella, RSV, influenza, SARS
3. Clinical, CXR

Question 5

For the following HAIs, ID the pathogen:

1. Bloodstream
2. UTI
3. Wound
4. Diarrhea
5. PNA

Answer 5

1. S. aureus, S. epi, Candida spp.
2. E. Coli, P aeruginosa, Acinetobacter spp., Candida spp.
3. S. auerus, S. epi
4. C. difficile
5. M. tuberculosis, Legionella spp., Aspergillus spp., E. Coli, P. aeruginosa, Acinetobacter spp.

Question 6

For central line-associated bloodstream infections (CLABSIs):

1. Pathogenesis
2. Organisms
3. Diagnosis

Answer 6

1. Skin, HWC, infusate, biofilm
2. S. epi, Candida