Microbiology 1 - Hospital acquired infection

Question 1

What if the most common disease caused by an HAI?

Answer 1

Hospital acquired pneumonia

Other common syndromes are surgical site infections, urinary catheter UTIs, bloodstream infections and GI infections

Question 2

What type of bacteria is c. difficile?

Answer 2

Gram pos spore-forming anaerobe

Question 3

Name the toxins produced by c. difficile

Answer 3

Toxins A and B

Question 4

What are the symptoms of C. difficile infection?

Answer 4

Diarrhoea -> severe colitis

Attack rates are higher in older, debilitated or antibiotic-treated patients

Question 5

Name 2 Antibiotics that are used to treat C. difficile?

Answer 5

Oral vancomycin is first-line nowadays
Metronidazole

Fidaxomicin - non-inferior to vancomycin and it lowers recurrence so now approved as well

Question 6

What type of bacteria is vancomycin effective against?

Answer 6

Gram pos

Question 7

What is the pathognemonic endoscope finding for C diff infection?

Answer 7

Columns of inflammatory exudate in colon lining

Question 8

How should C diff infection be managed?

Answer 8

1. Stop antibiotics
2. Fluid + electrolyte resuscitation for patients with diarrhoea
3. ORAL vancomycin/ metronidazole to combat C. diff
   Other options (but are VERY ££££££) are fidaxomicin or bezlotoxumab OR faecal transfer

Question 9

What are the most common causative pathogens in HAP?

Answer 9

S aureus
Klebsiella
Pseudomonas
Haemophilus

Question 10

Which 3 antibiotics can predispose you to C diff infection?

Answer 10

Cephalosporin
Clindamycin
Ciprofloxacin

Question 11

What is the prevalence of HAIs?

Answer 11

Approximately 8% of patients have a healthcare associated infection at any 1 time

Question 12

What proportion of HAIs are preventable?

Answer 12

Probably 15-30% - maybe higher (33%)

Question 13

Where do hospital microbes come from?

Answer 13

People (staff, other patients, visitors etc.) and equipment (hospitals are clean but not sterile)

Question 14

What proportion of HAI is caused by MRSA bacteraemia and C diff associated diarrhoea?

Answer 14

Only 15%

Question 15

How do the causative organisms of UTI change in hospital vs community?

Answer 15

In the community, E coli is by far the most common (over 80%) whereas in hospital, it is still the most common (over 50%) but other organisms like klebsiella, proteus and pseudomonas are relevant too

Question 16

Which factors contribute to the risk of surgical site infection?

Answer 16

Host defence, wound environment, pathogens