Byeonghak Kwak

Pasteurella multocida is an important zoonotic pathogen that causes soft-tissue infections in humans; however, recent antimicrobial susceptibility data in Korea remain limited. A total of 70 clinical P. multocida isolates collected at a nationwide commercial laboratory in Korea between November 2022 and July 2025 were analyzed. Antimicrobial susceptibility testing was performed using the disk diffusion method on Mueller-Hinton agar supplemented with 5% sheep blood. Five clinically relevant antimicrobial agents were tested: penicillin, amoxicillin-clavulanic acid (AMC), levofloxacin, tetracycline, and trimethoprim-sulfamethoxazole (TMP-SMX). For isolates classified as penicillin non-susceptible by disk diffusion, minimum inhibitory concentration (MIC) testing was performed using E-test and β-lactamase production was assessed using a phenotypic method. All tested isolates were susceptible to tetracycline and TMP-SMX by disk diffusion. Susceptibility rates by disk diffusion were 97.1% for AMC, 91.4% for levofloxacin, and 85.7% for penicillin. All 10 isolates initially classified as penicillin non-susceptible by disk diffusion were confirmed to be susceptible to penicillin by MIC testing and were β-lactamase negative. The 2 isolates classified as non-susceptible to AMC by disk diffusion were also β-lactamase negative and susceptible to penicillin by MIC testing. No β-lactam resistance was identified among the 70 clinical P. multocida isolates analyzed. These findings support current recommendations that β-lactams and other first-line agents remain active against P. multocida isolates in Korea.

Da Hye Kim, Young Geun Choi, Byeonghak Kwak, Hye Gyung Bae, Kyungwon Lee, Myungsook Kim. Korean J healthc assoc Infect Control Prev 2025;30:44-9. https://doi.org/10.14192/kjicp.2025.30.1.44