Healthcare associated infections

Question 1

How can you prevent Healthcare associated infections?

Answer 1

• Sterilisation
• Disinfection
• Hand washing

Question 2

A patient presents 3 weeks after heart surgery with a fever and malaise. What is the diagnosis and likely cause?

Answer 2

Endocarditis, a low grade pathogen (as its 3 weeks to develop) so strep viridans, enterococci or staph epidermidis

Question 3

What are some high grade pathogens that cause endocarditis?

Answer 3

Staph aureus (>50% of endocarditis), strep pyogenes

Question 4

What increases the risk for endocarditis?

Answer 4

• damaged heart valves allow for growth

* in dwelling catheters increase risk, espc. >4 days

Question 5

What is treatment for endocarditis?

Answer 5

• Flucoxacillin (s. aureus)

* Gentomicin (gram -ve enterococci)

Question 6

What are some complications of endocarditis?

Answer 6

• loss of valve due to microbial growth
• septic emboli
• immune complexes

Question 7

What is the long term treatment for endocarditis?

Answer 7

6 weeks of antibiotics to prevent biofilms forming

Question 8

Patient with septicaemia has bacteria cultured and grown on O2 HBA (no growth in AnO2). They form green-blue colonies and are gram -ve on microscopy. What is the likely pathogen?

Answer 8

Pseudomonas aurginosa

Question 9

What is the selective media for Pseudomonas aurginosa?

Answer 9

Centrimide (disinfectant)

Question 10

How is Pseudomonas aurginosa treated?

Answer 10

Resistant to all normal antimicrobials so use Piperacillin and tazobactum

Question 11

A patient contracts pneumonia and is treated with gentamicin. 5 days later she has abdominal pain and watery diarrhoea. What is the likely diagnosis?

Answer 11

Pseudomembranous colitis

Question 12

What causes Pseudomembranous colitis?

Answer 12

Gram +ve rod, clostridium difficile

Question 13

What else would have been looked for in a patient with abdominal pain and watery diarrhoea?

Answer 13

• salmonella
• shigella
• camplyobacteria

Question 14

What is the pathogenesis of Pseudomembranous colitis?

Answer 14

• Broad spectrum antibiotics kill normal flora

* C. difficle overgrowth, toxin damages endothelium causing necrosis

Question 15

What is the management of Pseudomembranous colitis?

Answer 15

• stop gentamicin

- treat with Metronidazole (for anaerobes) or if severe vancomycin

Question 16

How do you prevent C. difficile spread?

Answer 16

Its spore forming so chlorine or iodine to treat

Question 17

A patient receives a transplant from a donor with previous CMV infection. 3 weeks later, they test +ve for CMV on PCR. What are some possible complications?

Answer 17

• glandular fever like
• replication in organs that causes end organ failure
• retinitis

Question 18

A patient with suspected Hepatitis B has tests results of:
• anti HAV IgG +ve
• anti HBs +ve 
• HBsAg -ve
• Anti HCV +ve
What does this mean?

Answer 18

Past HAV or vaccinated
Vaccinated against HBV
Has a hep C infection

Question 19

What percentage of HCV infections become chronic and what of these get chronic liver damage?

Answer 19

-70-80% become carriers

Of these 40% have chronic liver damage

Question 20

What is the treatment for HCV?

Answer 20

• alpha interferon
• anti-virals
(protease inhibitors, RNA nuclei inhibitors)

Question 21

What are the four important factors in an Appropriate sterilisation process?

Answer 21

• D value
• Bioburden
• Level of sterility required
• Fragility of instrument

Question 22

What is the D value?

Answer 22

How quick you get a 10x decrease in bacteria (ease of sterility)

Question 23

What is bioburden?

Answer 23

Number of organisms you started with

Question 24

What does the level of sterility required depend on?

Answer 24

Procedure being performed