UTI Knowledge Center
Antibiotic Spotlight

Ampicillin

Emery Haley, PhD, Scientific Writing Specialist

Ampicillin

Find the Latest FDA-Approved Labelling Information Here: Drugs@FDA Online Database

Administrative Routes

Oral (PO) or Parenteral [intravenous infusion (IV)]

Other Names

Principen

Bacteriostatic or Bactericidal

Bactericidal [1]

Antibiotic Class

Penicillin (Beta-lactam)

Mechanisms of Action

Ampicillin, a beta-lactam antibiotic, binds to penicillin-binding proteins (PBPs) on bacterial cell walls. PBPs are essential for the formation of the peptidoglycan, which gives the bacterial wall strength and integrity. Binding of ampicillin to PBPs leads to failure of peptidoglycan cell wall synthesis, causing bacterial cell death.

WHO AWaRe Classification

Access [2]

Empiric Use Recommendations

No published guidance

Indication(s) Relevant to UTI

On label for UTIs caused by caused by Escherichia coli or Proteus mirabilis.

Checkmarks

CLSI and/or FDA documents support the efficacy of this antibiotic against the following organisms from the Guidance® UTI test: Aerococcus urinae, Corynebacterium riegelii, Escherichia coli, Proteus mirabilis, Streptococcus agalactiae, and Viridans Group Streptococci.  

Published primary literature supports the efficacy of this antibiotic against the following organisms from the Guidance® UTI test: Alloscardovia omnicolens ​[3]​, and Actinotignum schaalii ​​[4-6]

About the Author

Dr. Emery Haley is a scientific writing specialist with over ten years of experience in translational cell and molecular biology. As both a former laboratory scientist and an experienced science communicator, Dr. Haley is passionate about making complex research clear, approachable, and relevant. Their work has been published in over 10 papers and focuses on bridging the gap between the lab and real-world patient care to help drive better health outcomes.

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References
  1. Ishak, A.; Mazonakis, N.; Spernovasilis, N.; Akinosoglou, K.; Tsioutis, C. Bactericidal versus Bacteriostatic Antibacterials: Clinical Significance, Differences and Synergistic Potential in Clinical Practice. J. Antimicrob. Chemother. 2024, 80, 1–17, doi:10.1093/jac/dkae380
  2. AWaRe Classification of Antibiotics for Evaluation and Monitoring of Use, 2023 Available online: https://www.who.int/publications/i/item/WHO-MHP-HPS-EML-2023.04 (accessed on 6 February 2025).
  3. Isnard, C.; Lienhard, R.; Reissier, S.; Rodriguez, S.; Krähenbühl, J.; Liassine, N.; Guérin, F.; Cattoir, V. In Vitro Antimicrobial Susceptibility of Alloscardovia Omnicolens and Molecular Mechanisms of Acquired Resistance. Diagnostic Microbiology and Infectious Disease 2016, 84, 227–229, doi:10.1016/j.diagmicrobio.2015.08.009.
  4. Lotte, R.; Lotte, L.; Ruimy, R. Actinotignum Schaalii (Formerly Actinobaculum Schaalii): A Newly Recognized Pathogen—Review of the Literature. Clin Microbiol Infec 2016, 22, 28–36, doi:10.1016/j.cmi.2015.10.038.
  5. Beguelin, C.; Genne, D.; Varca, A.; Tritten, M. ‐L.; Siegrist, H.H.; Jaton, K.; Lienhard, R. Actinobaculum Schaalii: Clinical Observation of 20 Cases. Clin Microbiol Infec 2011, 17, 1027–1031, doi:10.1111/j.1469-0691.2010.03370.x.
  6. Sahuquillo-Arce, J.M.; Suárez-Urquiza, P.; Hernández-Cabezas, A.; Tofan, L.; Chouman-Arcas, R.; García-Hita, M.; Sabalza-Baztán, O.; Sellés-Sánchez, A.; Lozano-Rodríguez, N.; Martí-Cuñat, J.; et al. Actinotignum Schaalii Infection: Challenges in Diagnosis and Treatment. Heliyon 2024, 10, e28589, doi:10.1016/j.heliyon.2024.e28589.