Antimicrobial susceptibility and treatment of clinical cases of yersiniosis in Aotearoa | New Zealand

<p dir="ltr">Yersiniosis is the second most notified bacterial disease in Aotearoa | New Zealand (NZ). National clinical treatment guidelines for yersiniosis are available, but there is a lack of supporting antimicrobial susceptibility data for clinical isolates of <i>Yersinia</i> spp. and prescribing data for yersiniosis cases. Data were collected through interviews with 148 consenting individuals notified with yersiniosis. Forty-three percent (<i>n</i> = 63) of cases indicated antimicrobial use while symptomatic with yersiniosis, including two cases with dual diagnosis (Campylobacteriosis). Children under the age of 5 were predominantly notified with <i>Yersinia enterocolitica</i> (YE) biotype (BT) 2/3 (87%; 27/31) and reported significantly (<i>P</i> = 0.008) less antimicrobial use compared to adults (aged 20–70+ years). Antimicrobial use was significantly (<i>P</i> = 0.006) higher for cases reporting pre-existing gastrointestinal condition(s) and with YE BT 1A (26%; 12/47) compared to YE BT 2/3 (8%; 7/86). Eighty-six percent (44/51) of cases that indicated antimicrobial use identified the commencement date. Of these, 9% (4/44), 77% (34/44), and 14% (6/44) received an antimicrobial(s) as either empirical, directed, or empirical and directed treatment, respectively. Trimethoprim-sulfamethoxazole (49% [25/51]), ciprofloxacin (16% [8/51]), and doxycycline (10% [5/51]) were the most prescribed antimicrobials. Phenotypic antimicrobial susceptibility testing demonstrated clinical <i>Yersinia</i> spp. were susceptible to all antimicrobials commonly prescribed for the treatment of yersiniosis. Whole-genome sequence (WGS) analysis showed very few (<a href="https://journals.asm.org/doi/10.1128/spectrum.02751-24#core-collateral-B1" target="_blank">1</a><a href="https://journals.asm.org/doi/10.1128/spectrum.02751-24#core-collateral-B2" target="_blank">–</a><a href="https://journals.asm.org/doi/10.1128/spectrum.02751-24#core-collateral-B3" target="_blank">3</a>) antimicrobial resistance (AMR) genes within the <i>Yersinia</i> genomes. The results support the current antimicrobial prescribing recommendation for the treatment of yersiniosis in NZ and the utility of WGS to assess for AMR profiles in <i>Yersinia</i> spp.</p>