■在美国,鲍曼不动杆菌(Ab)病通常归因于1或2个单系碳青霉烯耐药性(CR)Ab谱系的爆发,这些谱系因地区而异。然而,在美国深南地区,关于CRAb流行病学和人口结构的知识有限,很少有研究比较当代CR和碳青霉烯类敏感(Cs)Ab,尽管后者相对流行。
■我们在伯明翰的大型医疗保健系统中对2462例Ab病例进行了多年分析,AL,并对89株2021年后的Ab分离株进行了测序,并通过抗生素敏感性试验进行了表型分析。
■尽管在我们的队列中累积CR率为17.7%,由于CsAb病例发病率的季节性变化,冬季月份的发病率定期增加,具体而言。基因分型的CRAb属于克隆组(CG)1,CG2,CG108,CG250或CG499,CG108,CG250和CG499的局部克隆持续多个月。没有任何CsAb谱系的克隆扩增。在CRAb分离物中,β-内酰胺抗生素抗性水平和相关遗传抗性决定子的库,其中包括新的赋予CR的FtsIA515V多态性,根据CG不同。CG108和CG499分离株对舒巴坦和甲氧苄啶/磺胺甲恶唑表现出特定的异抗性,分别,这导致微肉汤与基于琼脂的抗生素敏感性试验方式的敏感性结果不一致。
■我们报告了异常高度的CRAb系统发育多样性,主要是由新兴的美国血统驱动的,这些血统具有必须纳入诊断的新型抗性元素,监视,和临床前研究工作。
UNASSIGNED: Acinetobacter baumannii (Ab) disease in the United States is commonly attributed to outbreaks of 1 or 2 monophyletic carbapenem resistance (CR) Ab lineages that vary by region. However, there is limited knowledge regarding CRAb epidemiology and population structures in the U.S. Deep South, and few studies compare contemporary CR and carbapenem-susceptible (Cs) Ab, despite relative prevalence of the latter.
UNASSIGNED: We performed a multiyear analysis of 2462 Ab cases in a large healthcare system in Birmingham, AL, and 89 post-2021 Ab isolates were sequenced and phenotyped by antibiotic susceptibility tests.
UNASSIGNED: Although the cumulative CR rate was 17.7% in our cohort, rates regularly increased in winter months as result of seasonal changes in case incidence of CsAb, specifically. Genotyped CRAb belonged to clonal group (CG) 1, CG2, CG108, CG250, or CG499, with local clones of CG108, CG250, and CG499 persisting over multiple months. There was no clonal expansion of any CsAb lineage. Among CRAb isolates, levels of β-lactam antibiotic resistance and the repertoire of related genetic resistance determinants, which included the novel CR-conferring FtsI A515V polymorphism, differed according to CG. CG108 and CG499 isolates displayed specific
heteroresistance to sulbactam and trimethoprim/sulfamethoxazole, respectively, which resulted in discrepant susceptibility results in microbroth versus agar-based antibiotic susceptibility tests modalities.
UNASSIGNED: We report an unusually high degree of CRAb phylogenetic diversity principally driven by emergent U.S. lineages harboring novel resistance elements that must be incorporated into diagnostic, surveillance, and preclinical research efforts.