McCormack Alex, Hobbs Joanne K, Johnston Paul R, Coote Peter J
Biomedical Sciences Research Complex, School of Biology, University of St Andrews, The North Haugh, St Andrews KY16 9ST, Fife, UK.
School of Medicine, University of St Andrews, The North Haugh, St Andrews KY16 9TF, Fife, UK.
Antibiotics (Basel). 2025 May 15;14(5):507. doi: 10.3390/antibiotics14050507.
The aim of this work was to induce the formation of antibiotic-tolerant and/or persister cells in vivo using antibiotic therapy on larvae infected with , isolate these surviving cells, and characterise their phenotype and genotype. : Infected larvae were treated with effective doses of either ceftazidime or meropenem. Despite this, surviving colonies were isolated from living larvae, and antibiotic killing, fitness, virulence, antibiotic resistance and the whole genome sequence of a selection of these isolates were compared with their original parent strains. : The surviving isolates had an increased minimum duration to kill 99% of the population (MDK) upon exposure to ceftazidime or meropenem and decreased growth rates in culture, but they showed no change to the MIC or virulence-consistent with an antibiotic-tolerant phenotype. Long-read genome sequencing of selected isolates revealed only one single nucleotide polymorphism (SNP) within , encoding the lipoamide acyltransferase component of the branched-chain α-keto acid dehydrogenase, present in two independent isolates. However, time-kill assays with ceftazidime of knockout strains showed no significant change in the MDK. Concomitant with the antibiotic-tolerant phenotype, many of the isolates also had a reduced rate of killing when exposed to heat stress. : cells that survived antibiotic therapy in vivo were found to be antibiotic-tolerant and thermotolerant but not antibiotic-resistant and had reduced growth rates under optimal conditions but unchanged virulence. In the absence of a convincing genetic explanation, the co-induction of enhanced thermotolerance with antibiotic tolerance indicated that both are conferred by a heritable phenotypic mechanism.
这项工作的目的是在感染了[具体病原体]的幼虫体内使用抗生素疗法诱导形成抗生素耐受和/或持留菌细胞，分离这些存活细胞，并表征它们的表型和基因型。方法：用有效剂量的头孢他啶或美罗培南处理感染的幼虫。尽管如此，仍从存活的幼虫中分离出了存活菌落，并将这些分离株的抗生素杀灭效果、适应性、毒力、抗生素抗性以及部分分离株的全基因组序列与其原始亲本菌株进行了比较。结果：存活的分离株在接触头孢他啶或美罗培南后，杀灭99%群体的最短持续时间（MDK）增加，且在培养中的生长速率降低，但它们的最低抑菌浓度（MIC）或毒力没有变化——这与抗生素耐受表型一致。对选定分离株进行的长读长基因组测序显示，在编码支链α-酮酸脱氢酶的脂酰胺酰基转移酶组分的[基因名称]内，仅存在一个单核苷酸多态性（SNP），该SNP存在于两个独立的分离株中。然而，用头孢他啶对[基因名称]敲除菌株进行的时间杀灭试验显示，MDK没有显著变化。与抗生素耐受表型相伴的是，许多分离株在受到热应激时的杀灭速率也降低。结论：在体内经抗生素治疗后存活的[细菌名称]细胞被发现具有抗生素耐受性和热耐受性，但没有抗生素抗性，在最佳条件下生长速率降低，但毒力不变。在没有令人信服的遗传学解释的情况下，抗生素耐受性与增强的热耐受性的共同诱导表明，两者都是由一种可遗传的表型机制赋予的。
