Work

Minimum inhibitory concentration of penicillin as a surrogate for in vitro piperacillin susceptibility of ampicillin-susceptible Enterococcus faecalis

Year: 2025

Type: article

Abstract: • Accurate prediction of piperacillin and piperacillin/tazobactam susceptibility in E. faecalis is crucial for effective infection management. • CLSI guidelines recommend extrapolating piperacillin susceptibility from penicillin susceptibility, but this study challenges that approach. • E. faecalis strains with penicillin MICs of 4–8 µg/mL may be resistant to piperacillin and piperacillin/tazobactam, despite being penicillin-susceptible. • Penicillin MICs ≤2 µg/mL reliably predict piperacillin susceptibility, while MICs ≥8 µg/mL indicate resistance. This study evaluated whether penicillin MICs can predict piperacillin susceptibility in Enterococcus faecalis . Among 427 strains, 10 were resistant to piperacillin. Even strains with penicillin MICs of 4-8 µg/mL may exhibit resistance. These findings suggest that even penicillin MICs within the susceptible range may indicate piperacillin resistance, challenging CLSI guidelines.

Source: Diagnostic Microbiology and Infectious Disease

DOI: 10.1016/j.diagmicrobio.2025.116850

Authors: Kohei Hasegawa, Kumiko Suzuki, Kenya Murata, Yoshihiko Ogawa

Institution: Sakai Municipal Hospital

Language: English

Topic: Bacterial Identification and Susceptibility Testing

Subfield: Clinical Biochemistry

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

SDG: Good health and well-being

Open Access status: hybrid

Estimated APC paid: $3,290