Azlocillin is an acyl ampicillin antibiotic with an extended spectrum of activity and greater in vitro potency than the carboxy penicillins. Azlocillin is similar to. penicillin [pen″ĭ-sil´in] any of a large group of natural or semisynthetic antibacterial antibiotics derived directly or indirectly from strains of fungi of the. The interior surfaces of cars, truck, aircraft and marine vessels present additional opportunities for smart antimicrobial surfaces. Indications. It has similar spectrum of activity to cefalexin. RESPIRATORY TRACT INFECTIONS (e.g., tonsillitis, pharyngitis, and lobar pneumonia) caused by group A.