This is a tricky question, here we have a patient with alcoholism with frequent aspirations. On the top of that the patient is diabetic too. He is complaining of fever, weight loss, cough with expectoration with foul smelling sputum, so the first d/d is lung abscess due to anaerobes. Let us see the explanations from harrison: Lung abscess: A common feature is periodontal infection with pyorrhea or gingivitis. The usual symptoms are fatigue, cough, sputum production, and fever. Chills are uncommon. Many patients have evidence of chronic disease, such as weight loss and anemia. Some patients have putrid-smelling sputum indicative of the presence of anaerobes. This is usually treated with clindamycin; the initial IV dose of 600 mg four times daily can be changed to an oral dosage of 300 mg four times daily once the patient becomes afebrile and improves clinically. The duration of therapy is until imaging shows that chest lesions have cleared or have left a small, stable scar. An alternative to clindamycin is any B-lactam/-lactamase inhibitor combination; parenteral treatment may be followed by orally administered amoxicillin/clavulanate. Penicillin was previously regarded as a preferred drug for these infections, but many oral anaerobes produce -lactamases, and clindamycin proved superior to penicillin G in a randomized clinical trial. Metronidazole is highly active against viually all anaerobes but not against aerobic microaerophilic streptococci, which play an impoant role in mixed infections. In therapeutic trials, metronidazole has done poorly unless combined with a -lactam or another agent active against aerobic and microaerophilic streptococci. Patients with fevers persisting for 7-14 days should undergo bronchoscopy. Ref: Harrisons Principles of Medicine, 18th Edition, Chapter 258, Pages 2145-2146