Abstract
OBJECTIVES: Carbapenemase-producing Enterobacterales (CPE) represent a serious health care concern and their spread in animals has become alarming. Following several cases of CPE infections in a companion animal clinic, the role of the clinic backyard lawn used for dog relief walks of hospitalized dogs as a CPE reservoir has been investigated over a 4-year period (2020-2023). METHODS: Soil surface samples were taken through application of sterile wipes. After enrichment in Mueller-Hinton broth and selection on CHROMID® (OXA-48, CARBA) agar plates, isolates were identified by MALDI-TOF MS. CPE isolates were submitted to microdilution antimicrobial susceptibility testing and sequenced with short (Illumina) and long (ONT) read technologies to obtain complete circular genomes to perform antimicrobial resistance gene screening, phylogenetic (cgMLST, cgSNPs) and plasmid analyses. RESULTS: A total of 32 CPE representing eight different species were isolated, with E. coli (n = 15) and E. hormaechei (n = 7) being predominant. Genome-wide typing identified 11 different subtypes of E. coli and three of E. hormaechei, highlighting bacterial diversity. Thirty CPE contained an identical 63 589-bp IncL plasmid only differing by inversion of the blaOXA-48-containing transposon (Tn1999.2, invTn1999.2), and two CPE contained a 51 479-bp blaOXA-181-containing IncX3 plasmid. Strains associated with infections or carriage in hospitalized pets were also present in the lawn. CONCLUSIONS: The canine relief area of a veterinary clinic was identified as a long-term environmental reservoir for CPE, mainly due to the hyperepidemic blaOXA-48-positive IncL plasmid spreading between various bacterial species, emphasizing the urgent need for an extended hygiene concept including the outdoor environment.