Question 5

Outline the mechanisms of antimicrobial resistance (50% of marks).

Briefly outline the pharmacology of ciprofloxacin (50% of marks).

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College Answer

Most candidates had a structured answer to mechanisms of resistance that covered the major categories (alter target protein, prevent entry, efflux, degrade drug) and provided an example of a bacteria and the affected antibiotic, as was required to answer the question in full. Ciprofloxacin, whilst perhaps not a first line drug in the ICU, was not well known by many candidates. Better answers included a brief outline of class, mechanism of action (action on DNA gyrase to inhibit replication), spectrum (Gram negatives particularly mentioning Pseudomonas, lesser Gram-positive cover, not anaerobes, some atypical), PK (with correct dose, wide penetration into tissues including bone/prostate etc., predominantly renal excretion), side effects/toxicity (common or specific to cipro e.g. QT, tendinitis, arthropathy) and an example of resistance