Hoque M Nazmul, Rahman M Shaminur, Islam Tofazzal, Sultana Munawar, Crandall Keith A, Hossain M Anwar
Department of Gynecology, Obstetrics and Reproductive Health, Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Gazipur, 1706, Bangladesh.
Department of Microbiology, Jashore University of Science and Technology, Jashore, 7408, Bangladesh.
Anim Microbiome. 2022 Jul 6;4(1):43. doi: 10.1186/s42523-022-00193-w.
Mastitis pathogenesis involves a wide range of opportunistic and apparently resident microorganims including bacteria, viruses and archaea. In dairy animals, microbes reside in the host, interact with environment and evade the host immune system, providing a potential for host-tropism to favor mastitis pathogenesis. To understand the host-tropism phenomena of bovine-tropic mastitis microbiomes, we developed a cow-to-mouse mastitis model.
A cow-to-mouse mastitis model was established by fecal microbiota transplantation (FMT) and milk microbiota transplantation (MMT) to pregnant mice to assess microbiome dysbiosis and genomic functional perturbations through shotgun whole metagenome sequencing (WMS) along with histopathological changes in mice mammary gland and colon tissues.
The cow-to-mouse FMT and MMT from clinical mastitis (CM) cows induced mastitis syndromes in mice as evidenced by histopathological changes in mammary gland and colon tissues. The WMS of 24 samples including six milk (CM = 3, healthy; H = 3), six fecal (CM = 4, H = 2) samples from cows, and six fecal (CM = 4, H = 2) and six mammary tissue (CM = 3, H = 3) samples from mice generating 517.14 million reads (average: 21.55 million reads/sample) mapped to 2191 bacterial, 94 viral and 54 archaeal genomes. The Kruskal-Wallis test revealed significant differences (p = 0.009) in diversity, composition, and relative abundances in microbiomes between CM- and H-metagenomes. These differences in microbiome composition were mostly represented by Pseudomonas aeruginosa, Lactobacillus crispatus, Klebsiella oxytoca, Enterococcus faecalis, Pantoea dispersa in CM-cows (feces and milk), and Muribaculum spp., Duncaniella spp., Muribaculum intestinale, Bifidobacterium animalis, Escherichia coli, Staphylococcus aureus, Massilia oculi, Ralstonia pickettii in CM-mice (feces and mammary tissues). Different species of Clostridia, Bacteroida, Actinobacteria, Flavobacteriia and Betaproteobacteria had a strong co-occurrence and positive correlation as the indicator species of murine mastitis. However, both CM cows and mice shared few mastitis-associated microbial taxa (1.14%) and functional pathways regardless of conservation of mastitis syndromes, indicating the higher discrepancy in mastitis-associated microbiomes among lactating mammals.
We successfully induced mastitis by FMT and MMT that resulted in microbiome dysbiosis and genomic functional perturbations in mice. This study induced mastitis in a mouse model through FMT and MMT, which might be useful for further studies- focused on pathogen(s) involved in mastitis, their cross-talk among themselves and the host.
乳腺炎的发病机制涉及多种机会性微生物以及一些明显的常驻微生物，包括细菌、病毒和古菌。在奶牛中，微生物寄居于宿主体内，与环境相互作用并逃避宿主免疫系统，这为宿主嗜性促进乳腺炎发病机制提供了可能性。为了解牛嗜性乳腺炎微生物群的宿主嗜性现象，我们建立了一种牛至小鼠乳腺炎模型。
通过粪便微生物群移植（FMT）和乳汁微生物群移植（MMT）将微生物移植到怀孕小鼠体内，建立牛至小鼠乳腺炎模型，以通过鸟枪法全宏基因组测序（WMS）评估微生物群失调和基因组功能扰动，同时观察小鼠乳腺和结肠组织的组织病理学变化。
来自临床乳腺炎（CM）奶牛的牛至小鼠FMT和MMT在小鼠中诱发了乳腺炎综合征，乳腺和结肠组织的组织病理学变化证明了这一点。对24个样本进行WMS分析，这些样本包括来自奶牛的6份乳汁样本（CM = 3份，健康样本；H = 3份）、6份粪便样本（CM = 4份，H = 2份），以及来自小鼠的6份粪便样本（CM = 4份，H = 2份）和6份乳腺组织样本（CM = 3份，H = 3份），共产生5.1714亿条读数（平均：每份样本2155万条读数），这些读数被映射到2191个细菌、94个病毒和54个古菌基因组。Kruskal-Wallis检验显示，CM宏基因组和健康宏基因组之间的微生物群在多样性、组成和相对丰度方面存在显著差异（p = 0.009）。微生物群组成的这些差异主要表现为CM奶牛（粪便和乳汁）中的铜绿假单胞菌、卷曲乳杆菌、产酸克雷伯菌、粪肠球菌、分散泛菌，以及CM小鼠（粪便和乳腺组织）中的穆里杆菌属、邓肯氏菌属、肠道穆里杆菌、动物双歧杆菌、大肠杆菌、金黄色葡萄球菌、眼马赛菌、皮氏罗尔斯顿菌。不同种类的梭菌、拟杆菌、放线菌、黄杆菌纲和β-变形菌纲作为小鼠乳腺炎的指示物种具有很强的共现性和正相关性。然而，无论乳腺炎综合征是否保持一致，CM奶牛和小鼠中与乳腺炎相关的微生物分类群（1.14%）和功能途径都很少相同，这表明泌乳哺乳动物中与乳腺炎相关的微生物群存在较高差异。
我们通过FMT和MMT成功诱导了乳腺炎，导致小鼠微生物群失调和基因组功能扰动。本研究通过FMT和MMT在小鼠模型中诱导了乳腺炎，这可能有助于进一步研究乳腺炎相关病原体、它们之间的相互作用以及与宿主的相互作用。
