Institute of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway.
Department of Oral Rehabilitation & Biosciences, Oregon Health & Science University, Portland, OR, USA.
NPJ Biofilms Microbiomes. 2024 Apr 2;10(1):37. doi: 10.1038/s41522-024-00507-7.
Prolonged exposure to antibiotics at low concentration can promote processes associated with bacterial biofilm formation, virulence and antibiotic resistance. This can be of high relevance in microbial communities like the oral microbiome, where commensals and pathogens share a common habitat and where the total abundance of antibiotic resistance genes surpasses the abundance in the gut. Here, we used an ex vivo model of human oral biofilms to investigate the impact of ampicillin on biofilm viability. The ecological impact on the microbiome and resistome was investigated using shotgun metagenomics. The results showed that low concentrations promoted significant shifts in microbial taxonomic profile and could enhance biofilm viability by up to 1 to 2-log. For the resistome, low concentrations had no significant impact on antibiotic resistance gene (ARG) diversity, while ARG abundance decreased by up to 84%. A positive correlation was observed between reduced microbial diversity and reduced ARG abundance. The WHO priority pathogens Streptococcus pneumoniae and Staphylococcus aureus were identified in some of the samples, but their abundance was not significantly altered by ampicillin. Most of the antibiotic resistance genes that increased in abundance in the ampicillin group were associated with streptococci, including Streptococcus mitis, a well-known potential donor of ARGs to S. pneumoniae. Overall, the results highlight the potential of using the model to further our understanding of ecological and evolutionary forces driving antimicrobial resistance in oral microbiomes.
长期接触低浓度的抗生素会促进与细菌生物膜形成、毒力和抗生素耐药性相关的过程。这在口腔微生物组等微生物群落中尤为重要，在口腔微生物组中，共生菌和病原体共享共同的栖息地，并且抗生素耐药基因的总丰度超过了肠道中的丰度。在这里，我们使用人类口腔生物膜的离体模型来研究氨苄青霉素对生物膜活力的影响。使用 shotgun 宏基因组学研究了对微生物组和耐药组的生态影响。结果表明，低浓度显著促进了微生物分类群谱的显著变化，并可将生物膜活力提高多达 1 到 2 个对数级。对于耐药组，低浓度对抗生素耐药基因（ARG）多样性没有显著影响，而 ARG 丰度下降了多达 84%。微生物多样性降低与 ARG 丰度降低呈正相关。世界卫生组织优先病原体肺炎链球菌和金黄色葡萄球菌在一些样本中被鉴定出来，但它们的丰度没有被氨苄青霉素显著改变。在氨苄青霉素组中丰度增加的大多数抗生素耐药基因与链球菌有关，包括众所周知的肺炎链球菌 ARG 潜在供体——口腔链球菌。总体而言，这些结果强调了使用该模型来进一步了解口腔微生物组中驱动抗生素耐药性的生态和进化力量的潜力。
