Molecular communication is a relatively new communication paradigm for nanomachines where the communication is realized by utilizing existing biological components found in nature. In recent years, researchers have proposed using bacteria to realize molecular communication because the bacteria have, (i) the ability to swim and migrate between locations, (ii) the ability to carry DNA contents (i.e. plasmids), which could be utilized for information storage, and (iii) the ability to interact and transfer plasmids to other bacteria (one of this process is known as bacterial conjugation). However, current proposals for bacterial nanonetworks have not considered the internal structures of the nanomachines that can facilitate the use of bacteria as an information carrier. This article presents the types and functionalities of nanomachines that can be utilized in bacterial nanonetworks. A particular focus is placed on the bacterial conjugation and its support for multi-hop communication between nanomachines. Simulations of the communication process have also been evaluated, to analyze the quantity of bit received as well as the delay performances. Wet lab experiments have also been conducted to validate the bacterial conjugation process. The article also discusses potential applications of bacterial nanonetworks for cancer monitoring and therapy.