A 68 year old patient underwent a cholecystectomy in a hospital. On the fourth day of hospitilisation she developed a fever and increasing shortness of breath. Hospital acquired pneumonia was suspected. Her past medical history includes cholethisiasis, hypertension, type 2 DM, renal insufficiency (creatinine clearance 37ml/min) and osteoarthritis. The patient is documented to have sulfur allergy (reaction: skin rashes after taking sulfamethoxazole/trimethoprim). From preliminary culture results, multi-drug resistant pathogens are suspected.

a) State the risk factors for multi-drug resistance pathogens in this patient. (3 marks)

b) State the most probable pathogens that the treatment should cover (3 marks)

c) Suggest the most suitable antibiotic regimen for this patient with drug name, dosage regimen and duration of treatment. (7 marks)

d) The nurse inquires if the patient can be given a sulfonamide-containing drug, celecoxib, for her arthritis pain. How should the pharmacist respond? (2 marks)