Micro revision

Question 1

Describe mycoplasma

Answer 1

Pleomorphic
No cell wall so neither gram neg or gram positive
Penicillins won’t work

Question 2

Shape of campylobacter

Answer 2

S shaped

Question 3

Gram positives

Answer 3

Turn blue
Cocci = strep and staph
Bacilli = bacillus + clostridium (spore forming), corynebacterium + listeria (non spore forming)

Question 4

Gram negatives

Answer 4

Turn red
Usually enterobacteria
Diplococci = neisseria meningitis (notify public health!) + neisseria gonorrhea

Question 5

Classification of gram positives

Answer 5

Staph (catalase + and in clusters)

Strep (catalase - and in chains)

Question 6

Classification of staph

Answer 6

Coagulase + staph = staph aureus
Coagulase - staph = staph epidermidis + saprophyticus

Coagulase neg staph = cause illness with prosthetic devices

Question 7

What is coagulase?

Answer 7

Enzyme that activates prothrombin causing blood clots
Virulence factor
Only staph aureus has it

Question 8

What is group A strep?

Answer 8

Strep pyogenes

Question 9

Group D strep

Answer 9

Enterococcus faecalis - causes UTI, treat with amoxicillin or nitrofurantoin

Question 10

Group E strep

Answer 10

Enterococci

Question 11

How are strep classified?

Answer 11

Based on haemolysis of RBC
Alpha = partial haemolysis (strep viridans eg strep pneumoniae)
Beta = complete haemolysis

Question 12

Describe mycobacteria

Answer 12

Weakly gram neg but stain better with acid fast stain (Ziel Nielson) = TB

Question 13

Activity of flucloxacillin

Answer 13

No activity against gram neg

Question 14

Activity of vancomycin

Answer 14

No activity against gram neg

Question 15

What are enterococci resistant to?

Answer 15

Cephalosporins

Question 16

What abx cause a c diff risk?

Answer 16

Ciprofloxacin, co-amoxiclav, clindamycin and cephalosporins

Question 17

How do you treat CAP?

Answer 17

Usually strep pneumoniae

Treat with co-amoxiclav + clarithomycin

Question 18

What criteria is used for endocarditis?

Answer 18

Dukes

Question 19

Describe endocarditis treatment

Answer 19

Native = vancomycin + ciprofloxacin + rifampicin

Prosthetic = vancomycin + gentamicin + rifampicin

Question 20

How do you treat MSSA?

Answer 20

fluclox with oral switch, or vancomycin with clarithromycin switch

Question 21

How do you treat strep pyogenes?

Answer 21

ben pen (+ clindamycin if necrotising) with oral switch or vancomycin with clarithromycin switch

Question 22

How do you treat MRSA?

Answer 22

vancomycin with oral switch to clarithromycin

Question 23

What is important about tazocin?

Answer 23

doesnt cross blood brain barrier - don’t use for meningitis

Question 24

Treatment for septic arthritis

Answer 24

Usually staph aureus or beta haemolytic strep OR coagulase neg staph if prosthetic

Treat with fluclox or vancomycin

Question 25

Trimethoprim + methotrexate interaction

Answer 25

Both antagonise folate

Cause folate deficiency = severe harm + death

Question 26

When can you not prescribe tetracyclines?

Answer 26

Under 12 + pregnancy

Due to teeth discolouration + teratogenicity

Question 27

Management of pylonephritis

Answer 27

Ciprofloxacin

2nd line: co-amoxiclav

Question 28

Caution with ciprofloxacin

Answer 28

Tendon rupture