ampicillin

noun

am·​pi·​cil·​lin ˌam-pə-ˈsi-lən 

: a penicillin C₁₆H₁₉N₃O₄S that is effective against gram-negative and gram-positive bacteria and is used to treat various infections of the urinary, respiratory, and intestinal tracts

Examples of ampicillin in a Sentence

Recent Examples on the Web

Fortunately, all strains of the bug are still vulnerable to treatment with β-lactams like penicillin and ampicillin. —New Atlas, 8 Apr. 2025

Additionally, the researchers discovered that the hemolymph proteins improved the effectiveness of conventional antibiotics ampicillin, gentamicin, trimethoprim and ciprofloxacin by two- to 32-fold against clinically important bacteria. —New Atlas, 21 Jan. 2025

More than 80 percent of infections are caused by E. coli, and in a 2022 report, the World Health Organization found that one in five UTI infections caused by E. coli showed reduced susceptibility to standard antibiotics like ampicillin, co-trimoxazole, and fluoroquinolones. —Emily Mullin, WIRED, 10 Sep. 2024

The penicillin family contains ampicillin, which is usually injected, and amoxicillin, which is often administered as a pill. —Dhruv Khullar, The New Yorker, 2 Sep. 2024

Authorities said investigators from the Department of Consumer Protection also allegedly found these violations: Sale of foreign prescription pharmaceuticals, including sildenafil used to treat erectile dysfunction and ampicillin, and an antibiotic used to manage and treat bacterial infections. —Staff Report, Hartford Courant, 25 July 2024

Listeria is generally treated with the common antibiotic ampicillin. —Mark Kortepeter, Forbes, 14 Feb. 2024

Treatment with trimethoprim-sulfamethoxazole is used as an alternative for penicillin-allergic patients (since ampicillin is a penicillin derivative). —Mark Kortepeter, Forbes, 14 Feb. 2024

Examples of penicillin drugs are amoxicillin, ampicillin, and oxacillin. Methoxyflurane. —Angela Palmer, Verywell Health, 3 May 2023

Word History

Etymology

am(ino) + p(en)icillin

First Known Use

1961, in the meaning defined above

Rhymes for ampicillin

• methicillin
• penicillin
• pyroxylin
• amoxicillin
• carbenicillin
• haematoxylin
• millon
• villain
• vanillin

Medical Definition

ampicillin

noun

am·​pi·​cil·​lin ˌam-pə-ˈsil-ən 

: a penicillin C₁₆H₁₉N₃O₄S that is effective against gram-negative and gram-positive bacteria and is used in anhydrous forms, as the trihydrate, or as the sodium salt to treat various infections of the urinary, respiratory, and intestinal tracts see penbritin