The most numerous cells in the lungs are dust cells, also known by their scientific term of alveolar marcrophages.
These cells are located in any person's lungs and are responsible for keeping your lungs and air pipes clean of any dust particles and other materials that may harm your body. Their role is to destroy any foreign substances, such as bacteria and others.
Antibiotic resistance is a consequence of evolution via natural selection. The antibiotic action is an environmental pressure; those bacteria which have a mutation allowing them to survive will live on to reproduce. They will then pass this trait to their offspring, which will be a fully resistant generation.