Emergence of a CTX-M-14- ESBL-Producing Multidrug-Resistant Pasteurella multocida from Human Bacteremia in China: A Case Report and Literature Review

Abstract: Pasteurella multocida ( P. multocida ) bloodstream infections in humans without a history of animal bites are commonly associated with immunocompromise. Empirical therapy typically involves a β-lactam/β-lactamase inhibitor combination (eg, amoxicillin-clavulanate), but a small number of amoxicillin-clavulanate–resistant strains have been reported. Herein, we report a rare case of human P. multocida bacteremia in a patient with no history of animal bites. Antibacterial susceptibility testing showed the strain was sensitive to trimethoprim-sulfamethoxazole; resistant to erythromycin; and non-susceptible to azithromycin, levofloxacin, tetracycline, penicillin, ampicillin, amoxicillin-clavulanate and ceftriaxone. Whole-genome sequencing (WGS) confirmed the presence of CTX-M-14-type extended-spectrum β-lactamases (ESBLs). The potential emergence of multidrug-resistant (MDR) P. multocida may challenge the empirical treatment of the strain. This case highlights the necessity of studying the antibiotic susceptibility patterns of P. multocida in humans and animals, as well as the need for a One Health approach. Keywords: Pasteurella multocida , extended-spectrum β-lactamases, ESBLs, multidrug-resistant, whole-genome sequencing, one health