Objectives: The emergence of pathogens that are resistant to both tigecycline and carbapenem poses a threat to public health globally. Continuous emergence of novel tet (X) variants accelerates the tigecycline resistance crisis. This study aimed to characterise the novel tigecycline resistance gene tet (X22) and its coexistence with carbapenem resistance gene bla NDM-1 in Pseudomonas caeni. Methods: This P. caeni isolate co-harbouring tet (X22) and bla NDM-1 was systematically investigated using antimicrobial susceptibility testing, conjugation assays, genome sequencing, bioinformatic analyses, cloning of tet (X22) and functional analysis, and protein structure prediction. Results: The carbapenem-resistant and tigecycline-resistant P. caeni isolate CE14 was obtained from chicken faeces in 2022. CE14 carried multiple antibiotic resistance genes, including the novel tet (X22) and bla NDM-1 . Tet(X22) exhibited 64.72-90.48% amino acid identity with other variants [Tet(X) to Tet(X21)]. Cloning of the gene tet (X22) and protein structure prediction revealed that Tet(X22) confers resistance to tetracyclines, including tigecycline. tet (X22) and bla NDM-1 were located in two multidrug-resistant regions of the chromosome. Conclusions: The occurrence of the novel IS CR2 -flanked tet (X22) in P. caeni suggests that the tet (X) variant has adapted to new hosts and may widely spread to further expand the host range. The future global spread of such pathogens co-harbouring tet (X) and bla NDM variants needs to be continuously monitored according to the One Health approach. (c) 2023 Elsevier Ltd and International Society of Antimicrobial Chemotherapy. All rights reserved.

用促卵泡素(FSH)和孕马血清促性腺激素(PMSG)对橘猫进行超数排卵,手术法冲取卵母细胞,并对卵巢上的排卵点和获卵数进行统计,探讨不同激素和重复超排对橘猫超排效果的影响.结果 表明:FSH组排卵点数和卵母细胞数分别为6.8和8.8个,国产PMSG组和韩国PMSG组排卵点数和卵母细胞数分别为5.1、7.7及6.2、8.5个,3组间排卵点数和卵母细胞数差异不显著;重复超排时,国产FSH组超排获得的排卵点数和卵母细胞数分别为3.5和5.2个,国产PMSG组排卵点数和卵母细胞数分别为3.1和4.5个,两组间排卵点数和卵母细胞数差异不显著.这一研究说明FSH和PMSG均可用于家猫超数排卵,为开展家猫胚胎工程相关研究奠定了基础.