Naudin Sarah A, Ferran Aude A, Imazaki Pedro Henrique, Arpaillange Nathalie, Marcuzzo Camille, Vienne Maïna, Demmou Sofia, Bousquet-Mélou Alain, Ramon-Portugal Felipe, Lacroix Marlene Z, Hoede Claire, Barret Maialen, Dupouy Véronique, Bibbal Delphine
INTHERES, Université de Toulouse, INRAE, ENVT, Toulouse, France.
Université de Toulouse, INRAE, BioinfOmics, GenoToul Bioinformatics Facility, Castanet-Tolosan, France.
Front Microbiol. 2024 Mar 27;15:1377047. doi: 10.3389/fmicb.2024.1377047. eCollection 2024.
Sewer biofilms are likely to constitute hotspots for selecting and accumulating antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs). This study aimed to optimize culture conditions to obtain biofilms, mimicking the biofilm collected in sewers, to study the impact of fluoroquinolones (FQs) on sewer biofilm microbiota. Biofilms were grown on coupons in CDC Biofilm Reactors®, continuously fed with nutrients and inoculum (1/100 diluted wastewater). Different culture conditions were tested: (i) initial inoculum: diluted wastewater with or without sewer biofilm, (ii) coupon material: concrete vs. polycarbonate, and (iii) time of culture: 7 versus 14 days. This study found that the biomass was highest when biofilms were formed on concrete coupons. The biofilm taxonomic diversity was not affected by adding sewer biofilm to the initial inoculum nor by the coupon material. and dominated in the sewer biofilm composition, whereas biofilms were mainly composed of . The relative abundance of and genes was higher in biofilms than sewer biofilm. The resistome of sewer biofilm showed the highest Shannon diversity index compared to wastewater and biofilms. A PCoA analysis showed differentiation of samples according to the nature of the sample, and a Procrustes analysis showed that the ARG changes observed were linked to changes in the microbial community. The following growing conditions were selected for biofilms: concrete coupons, initial inoculation with sewer biofilm, and a culture duration of 14 days. Then, biofilms were established under high and low concentrations of FQs to validate our biofilm model. Fluoroquinolone exposure had no significant impact on the abundance of genes, but high concentration exposure increased the proportion of mutations in A (codons S83L and D87N) and C (codon S80I). In conclusion, this study allowed the determination of the culture conditions to develop an model of sewer biofilm; and was successfully used to investigate the impact of FQs on sewer microbiota. In the future, this setup could be used to clarify the role of sewer biofilms in disseminating resistance to FQs in the environment.
下水道生物膜很可能是筛选和积累抗生素抗性细菌（ARB）及抗生素抗性基因（ARG）的热点区域。本研究旨在优化培养条件以获得类似下水道中收集到的生物膜，从而研究氟喹诺酮类药物（FQs）对下水道生物膜微生物群的影响。生物膜在CDC生物膜反应器®中的试片上生长，持续供应营养物和接种物（1/100稀释的废水）。测试了不同的培养条件：（i）初始接种物：含或不含下水道生物膜的稀释废水，（ii）试片材料：混凝土与聚碳酸酯，以及（iii）培养时间：7天与14天。本研究发现，当生物膜在混凝土试片上形成时生物量最高。生物膜的分类多样性不受初始接种物中添加下水道生物膜的影响，也不受试片材料的影响。 和 在下水道生物膜组成中占主导地位，而 生物膜主要由 组成。 和 基因的相对丰度在 生物膜中高于下水道生物膜。与废水和 生物膜相比，下水道生物膜的抗性组显示出最高的香农多样性指数。主坐标分析（PCoA）表明样品根据样品性质存在差异，而普氏分析表明观察到的ARG变化与微生物群落的变化有关。为 生物膜选择了以下生长条件：混凝土试片、用下水道生物膜进行初始接种以及14天的培养持续时间。然后，在高浓度和低浓度FQs条件下建立生物膜以验证我们的 生物膜模型。氟喹诺酮暴露对 基因的丰度没有显著影响，但高浓度暴露增加了A（密码子S83L和D87N）和C（密码子S80I）中突变的比例。总之，本研究确定了培养条件以建立下水道生物膜的 模型；并成功用于研究FQs对下水道微生物群的影响。未来，该装置可用于阐明下水道生物膜在环境中传播对FQs抗性的作用。
