<prompt> Corynebacterium diphtheriae isGram positiveResistant to penicillinGram negativeResistant to chloramphenicol  <response>: Corynebacterium diphtheriae is a gram-positive bacillus that is unencapsulated, nonmotile, and nonsporulating. The bacteria have a characteristic club-shaped bacillary appearance and typically form clusters of parallel rays, or palisades, that are referred to as Chinese characters.Recommended treatment options for patients with respiratory diphtheria are as follows: Procaine penicillin G, 600,000 U IM q12h for children: 12,500-25,000 Ukg IM q12h until the patient can swallow comfoably; then oral penicillin V, 125-250 mg qid to complete a 14-day course Erythromycin, 500 mg IV q6h for children: 40-50 mgkg per day IV in two or four divided doses until the patient can swallow comfoably; then 500 mg PO qid to complete a 14-day courseRef: Harrison;s Principles of Internal Medicine; 19th edition; Chapter 175; Diphtheria and Other Corynebacterial Infections 