Third Generation Cephalosporin Resistant <i>Enterobacterales</i> Infections in Hospitalized Horses and Donkeys: A Case–Case–Control Analysis

• Main Authors: Anat Shnaiderman-Torban, Dror Marchaim, Shiri Navon-Venezia, Ori Lubrani, Yossi Paitan, Haya Arielly, Amir Steinman
• Format: Article
• Language: English
• Published: MDPI AG 2021-02-01
• Series: Antibiotics
• Subjects: cephalosporins; extended-spectrum β-lactamase; equine; resistance; case–case–control
• Online Access: https://www.mdpi.com/2079-6382/10/2/155

In human medicine, infections caused by third-generation cephalosporin-resistant <i>Enterobacterales</i> (3GCRE) are associated with detrimental outcomes. In veterinary medicine, controlled epidemiological analyses are lacking. A matched case–case–control investigation (1:1:1 ratio) was conducted in a large veterinary hospital (2017–2019). In total, 29 infected horses and donkeys were matched to 29 animals with third-generation cephalosporin-susceptible <i>Enterobacterales</i> (3GCSE) infections, and 29 uninfected controls (overall <i>n</i> = 87). Despite multiple significant associations per bivariable analyses, the only independent predictor for 3GCRE infection was recent exposure to antibiotics (adjusted odds ratio (aOR) = 104, <i>p</i> < 0.001), but this was also an independent predictor for 3GCSE infection (aOR = 22, <i>p</i> < 0.001), though the correlation with 3GCRE was significantly stronger (aOR = 9.3, <i>p</i> = 0.04). In separated multivariable outcome models, 3GCRE infections were independently associated with reduced clinical cure rates (aOR = 6.84, <i>p</i> = 0.003) and with 90 days mortality (aOR = 3.6, <i>p</i> = 0.003). <i>Klebsiella</i> spp. were the most common 3GCRE (36%), and <i>bla</i>_CTX-M-1 was the major β-lactamase (79%). Polyclonality and multiple sequence types were evident among all <i>Enterobacterales</i> (e.g., <i>Klebsiella pneumoniae</i>, <i>Escherichia coli</i>, <i>Enterobacter cloacae</i>). The study substantiates the significance of 3GCRE infections in equine medicine, and their independent detrimental impact on cure rates and mortality. Multiple <i>Enterobacterales</i> genera, subtypes, clones and mechanisms of resistance are prevalent among horses and donkeys with 3GCRE infections.