Abstract：
OBJECTIVE: The emergence of carbapenem-resistant Pseudomonas putida (CRPP) has raised public awareness. This study investigated two strains from the Pseudomonas putida group that were resistant to carbapenem, tigecycline, and aztreonam-avibactam (ATM-AVI), with a focus on their microbial and genomic characteristics.
METHODS: We assessed the antibiotic resistance profile using broth dilution, disk diffusion, and E-test methods. Efflux pump phenotype testing and real-time quantitative PCR were employed to evaluate efflux pump activity in tigecycline resistance, while polymerase chain reaction was utilized to detect common carbapenem genes. Additionally, whole-genome sequencing was performed to analyze genomic characteristics. The transferability of blaIMP-1 and blaAFM-4 was assessed through a conjugation experiment. Furthermore, growth kinetics and biofilm formation were examined using growth curves and crystal violet staining.
RESULTS: Both strains demonstrated resistance to carbapenem, tigecycline, and ATM-AVI. Notably, NMP can restore sensitivity to tigecycline. Subsequent analysis revealed that they co-produced blaIMP-1, blaAFM-4, tmexCD-toprJ, and blaOXA-1041, belonging to a novel sequence type ST268. Although they were closely related on the phylogenetic tree, they exhibited different levels of virulence. Genetic environment analysis indicated variations compared to prior studies, particularly regarding the blaIMP-1 and blaAFM-4 genes, which showed limited horizontal transferability. Moreover, it was observed that temperature exerted a specific influence on their biological factors.
CONCLUSIONS: We initially identified two P. putida ST268 strains co-producing blaIMP-1, blaAFM-4, blaOXA-1041, and tmexCD-toprJ. The resistance to tigecycline and ATM-AVI can be attributed to the presence of multiple drug resistance determinants. These findings underscore the significance of P. putida as a reservoir for novel antibiotic resistance genes. Therefore, it is imperative to develop alternative antibiotic therapies and establish effective monitoring of bacterial resistance.
METHODS: We assessed the antibiotic resistance profile using broth dilution, disk diffusion, and E-test methods. Efflux pump phenotype testing and real-time quantitative PCR were employed to evaluate efflux pump activity in tigecycline resistance, while polymerase chain reaction was utilized to detect common carbapenem genes. Additionally, whole-genome sequencing was performed to analyze genomic characteristics. The transferability of blaIMP-1 and blaAFM-4 was assessed through a conjugation experiment. Furthermore, growth kinetics and biofilm formation were examined using growth curves and crystal violet staining.
RESULTS: Both strains demonstrated resistance to carbapenem, tigecycline, and ATM-AVI. Notably, NMP can restore sensitivity to tigecycline. Subsequent analysis revealed that they co-produced blaIMP-1, blaAFM-4, tmexCD-toprJ, and blaOXA-1041, belonging to a novel sequence type ST268. Although they were closely related on the phylogenetic tree, they exhibited different levels of virulence. Genetic environment analysis indicated variations compared to prior studies, particularly regarding the blaIMP-1 and blaAFM-4 genes, which showed limited horizontal transferability. Moreover, it was observed that temperature exerted a specific influence on their biological factors.
CONCLUSIONS: We initially identified two P. putida ST268 strains co-producing blaIMP-1, blaAFM-4, blaOXA-1041, and tmexCD-toprJ. The resistance to tigecycline and ATM-AVI can be attributed to the presence of multiple drug resistance determinants. These findings underscore the significance of P. putida as a reservoir for novel antibiotic resistance genes. Therefore, it is imperative to develop alternative antibiotic therapies and establish effective monitoring of bacterial resistance.
摘要：
目的：耐碳青霉烯类恶臭假单胞菌（CRPP）的出现提高了公众的认识。这项研究调查了来自恶臭假单胞菌组的两株对碳青霉烯耐药的菌株，替加环素,和氨曲南-阿维巴坦（ATM-AVI），专注于它们的微生物和基因组特征。
方法：我们使用肉汤稀释评估了抗生素耐药性，磁盘扩散，和电子测试方法。外排泵表型测试和实时定量PCR用于评估替加环素耐药性的外排泵活性，而聚合酶链反应用于检测常见的碳青霉烯基因。此外,进行全基因组测序以分析基因组特征.通过缀合实验评估blaIMP-1和blaAFM-4的可转移性。此外，使用生长曲线和结晶紫染色检查生长动力学和生物膜形成。
结果：两种菌株均表现出对碳青霉烯的抗性，替加环素,ATM-AVI.值得注意的是,NMP可以恢复对替加环素的敏感性。随后的分析表明，他们共同生产了blaIMP-1，blaAFM-4，tmexCD-toprJ，和blaOXA-1041,属于新型序列类型ST268。尽管它们在系统发育树中密切相关，它们表现出不同程度的毒力。遗传环境分析表明与以前的研究相比存在差异，特别是关于blaIMP-1和blaAFM-4基因，显示出有限的水平转移性。此外，据观察，温度对它们的生物因素有特定的影响。
结论：我们最初鉴定了两种共同产生blaIMP-1、blaAFM-4、blaOXA-1041和tmexCD-toprJ的恶臭假单胞菌ST268菌株。对替加环素和ATM-AVI的抗性可归因于多种药物抗性决定子的存在。这些发现强调了恶臭假单胞菌作为新型抗生素抗性基因的储库的重要性。因此,必须开发替代抗生素疗法并建立有效的细菌耐药性监测。
方法：我们使用肉汤稀释评估了抗生素耐药性，磁盘扩散，和电子测试方法。外排泵表型测试和实时定量PCR用于评估替加环素耐药性的外排泵活性，而聚合酶链反应用于检测常见的碳青霉烯基因。此外,进行全基因组测序以分析基因组特征.通过缀合实验评估blaIMP-1和blaAFM-4的可转移性。此外，使用生长曲线和结晶紫染色检查生长动力学和生物膜形成。
结果：两种菌株均表现出对碳青霉烯的抗性，替加环素,ATM-AVI.值得注意的是,NMP可以恢复对替加环素的敏感性。随后的分析表明，他们共同生产了blaIMP-1，blaAFM-4，tmexCD-toprJ，和blaOXA-1041,属于新型序列类型ST268。尽管它们在系统发育树中密切相关，它们表现出不同程度的毒力。遗传环境分析表明与以前的研究相比存在差异，特别是关于blaIMP-1和blaAFM-4基因，显示出有限的水平转移性。此外，据观察，温度对它们的生物因素有特定的影响。
结论：我们最初鉴定了两种共同产生blaIMP-1、blaAFM-4、blaOXA-1041和tmexCD-toprJ的恶臭假单胞菌ST268菌株。对替加环素和ATM-AVI的抗性可归因于多种药物抗性决定子的存在。这些发现强调了恶臭假单胞菌作为新型抗生素抗性基因的储库的重要性。因此,必须开发替代抗生素疗法并建立有效的细菌耐药性监测。
