A 52-year-old lady is admitted with urosepsis. Her past medical history includes type 2 diabetes and hypertension. She has a history of drug allergy with a maculopapular rash developing several days after taking amoxicillin. On admission, she was febrile and tachycardic. Her investigations showed normal renal and liver function tests and an elevated white blood cell count. Escherichia coli was present in her blood and urine cultures with sensitivities are pending. 

(a) What class of antibiotics does amoxicillin belong to? What is the mechanism of antibacterial action? 

(3 marks) 

(b) Name TWO antibiotics that have excellent oral bioavailability (>90%). What are the problems with prolonged intravenous (“IV”) antibiotic use? Under what conditions would you consider switching from IV to oral antibiotics? 

(5 marks) 

(c) Name THREE antibiotics that can provide good cover against gram negative organisms. 

(3 marks) 

(d) Describe the types of allergic reaction that can occur with penicillin. Which cephalosporins have the lowest risk of cross-reactivity in a patient with penicillin allergy? Which side chain is responsible for cross reactivity? 

(5 marks) 

(e) Cultures subsequently confirmed extended spectrum beta-lactamase (“ESBL”) E. coli in the blood and urine. What antibiotics may bé effective against ESBL urinary tract infections? What measures can be taken to reduce antibiotic resistance?  

(4 marks)