First report of blaOXA-181-carrying IncX3 plasmids in multidrug-resistant Enterobacter hormaechei and Serratia nevei recovered from canine and feline opportunistic infections.

Whole-genome sequence analysis of six Enterobacter hormaechei and two Serratia nevei strains, using a hybrid assembly of Illumina and Oxford Nanopore Technologies sequencing, revealed the presence of the epidemic blaOXA-181-carrying IncX3 plasmids co-harboring qnrS1 and ∆ere(A) genes, as well as multiple multidrug resistance (MDR) plasmids disseminating in all strains, originated from dogs and cats in Thailand. The subspecies and sequence types (ST) of the E. hormaechei strains recovered from canine and feline opportunistic infections included E. hormaechei subsp. xiangfangensis ST171 (n = 3), ST121 (n = 1), and ST182 (n = 1), as well as E. hormaechei subsp. steigerwaltii ST65 (n = 1). Five of the six E. hormaechei strains harbored an identical 51,479-bp blaOXA-181-carrying IncX3 plasmid. However, the blaOXA-181 plasmid (pCUVET22-969.1) of the E. hormaechei strain CUVET22-969 presented a variation due to the insertion of ISKpn74 and ISSbo1 into the virB region. Additionally, the blaOXA-181 plasmids of S. nevei strains were nearly identical to the others at the nucleotide level, with ISEcl1 inserted upstream of the qnrS1 gene. The E. hormaechei and S. nevei lineages from canine and feline origins might acquire the epidemic blaOXA-181-carrying IncX3 and MDR plasmids, which are shared among Enterobacterales, contributing to the development of resistance. These findings suggest the spillover of significant OXA-181-encoding plasmids to these bacteria, causing severe opportunistic infections in dogs and cats in Thailand. Surveillance and effective hygienic practice, especially in hospitalized animals and veterinary hospitals, should be urgently implemented to prevent the spread of these plasmids in healthcare settings and communities. IMPORTANCE: blaOXA-181 is a significant carbapenemase-encoding gene, usually associated with an epidemic IncX3 plasmid found in Enterobacterales worldwide. In this article, we revealed six carbapenemase-producing (CP) Enterobacter hormaechei and two CP Serratia nevei strains harboring blaOXA-181-carrying IncX3 and multidrug resistance plasmids recovered from dogs and cats in Thailand. The carriage of these plasmids can promote extensively drug-resistant properties, limiting antimicrobial treatment options in veterinary medicine. Since E. hormaechei and S. nevei harboring blaOXA-181-carrying IncX3 plasmids have not been previously reported in dogs and cats, our findings provide the first evidence of dissemination of the epidemic plasmids in these bacterial species isolated from animal origins. Pets in communities can serve as reservoirs of significant antimicrobial resistance determinants. This situation places a burden on antimicrobial treatment in small animal practice and poses a public health threat.

Emergence and multi-lineages of carbapenemase-producing Acinetobacter baumannii-calcoaceticus complex from canine and feline origins.

The carbapenemase-producing Acinetobacter baumannii is an important opportunistic bacterium and frequently causes hospital-acquired infections in humans. It also has increasingly been reported in veterinary medicine. This study illustrates multiple clones of carbapenemase-producing A. baumannii disseminating and causing diseases in dogs and cats in Thailand. Between 2016 and 2020, 44 A. baumannii and two A. pittii isolates exhibiting imipenem resistance (MIC≥16 µg/mL) from diagnostic samples were characterized by Pasteur multilocus sequence typing (MLST), sequence grouping (SG), repetitive extragenic palindromic element (rep)-PCR fingerprint analysis and antimicrobial resistance (AMR) profiling. All isolates contained blaOXA-23 in the Tn2006 family, and A. baumannii showed the sequence type (ST) 16 (14/44), ST149 (12/44), ST25 (6/44), ST2 (4/44), ST1581 (3/44), ST23 (2/44), ST1575 (1/44) and ST1576 (1/44). DNA fingerprint analysis and SG illustrated clonal relationships in the STs and its single locus variants, and AMR gene profiles, including tetracycline and aminoglycoside resistance genes, showed minor variations in the clones. The findings suggest that blaOXA-23 has been spread in multiple clones of A. baumannii and A. pittii from canine and feline hosts. With the collection of multiple AMR genes and intrinsic resistance, antimicrobial options are limited for treatment, and pets can be a potential reservoir of extensively drug-resistant, carbapenemase-producing A. baumannii in the community. Epidemiological tracking by passive and active surveillance in animals, veterinary personnel and hospital environment and preventive measurements should be promoted to decrease the risk of infection and transmission to humans.