Evaluation of Bacteria and Fungi DNA Abundance in Human Tissues
Gabriela Estrela de Albuquerque, Bruno S. Moda, Marianna Sampaio Serpa, Gabriela Pereira Branco, Alexandre Defelicibus, Isabella K. T. M. Takenaka, María Galli de Amorim, Elizabeth C. Miola, Valquíria do Carmo Alves Martins, Kátia Luz Torres, Stephania Martins Bezerra, Laura Carolina López Claro, Adriane Pelosof, Cláudia Zitron, Laís Lie Senda de Abrantes, Felipe José Fernández Coimbra, Luiz Paulo Kowalski, Fábio Abreu Alves, Stênio de Cássio Zéqui, Klas I. Udekwu, Israel Tojal da Silva, Diana Noronha Nunes, Thais Fernanda Bartelli, Emmanuel Dias‐Neto
Abstract
Whereas targeted and shotgun sequencing approaches are both powerful in allowing the study of tissue-associated microbiota, the human: microorganism abundance ratios in tissues of interest will ultimately determine the most suitable sequencing approach. In addition, it is possible that the knowledge of the relative abundance of bacteria and fungi during a treatment course or in pathological conditions can be relevant in many medical conditions. Here, we present a qPCR-targeted approach to determine the absolute and relative amounts of bacteria and fungi and demonstrate their relative DNA abundance in nine different human tissue types for a total of 87 samples. In these tissues, fungi genomes are more abundant in stool and skin samples but have much lower levels in other tissues. Bacteria genomes prevail in stool, skin, oral swabs, saliva, and gastric fluids. These findings were confirmed by shotgun sequencing for stool and gastric fluids. This approach may contribute to a more comprehensive view of the human microbiota in targeted studies for assessing the abundance levels of microorganisms during disease treatment/progression and to indicate the most informative methods for studying microbial composition (shotgun versus targeted sequencing) for various samples types.