Final answer:
The predominant pathogens of the lower respiratory tract include bacteria like Pseudomonas and Streptococcus, as well as various viruses that cause the common cold and flu.
Step-by-step explanation:
The lower respiratory tract includes structures such as the trachea, bronchi, and alveoli where gas exchange occurs. While this area is not heavily populated with microbes when compared to the upper respiratory tract, there are still pathogens that have been identified.
Among the bacteria, species such as Pseudomonas, Streptococcus, Prevotella, Fusobacterium, and Veillonella are the most commonly identified, although it is unclear if they are part of a normal microbiota or transient species.
Viruses are the most frequent cause of respiratory tract infections and these infections often have mild and self-limiting outcomes, although few therapies exist to effectively combat viral infections.
Some common virus-caused illnesses include the common cold and influenza.
Bacterial diseases such as tuberculosis, whooping cough, and acute bronchitis are capable of causing more serious disease and can be treated with antibiotics. The treatment and prevention strategies also include vaccines for many bacterial and viral respiratory pathogens to mitigate the spread of these infectious agents.
It's also significant to note that many members of the respiratory system's normal microbiota are opportunistic pathogens. Potentially pathogenic bacteria produce several virulence factors to establish infection, overcome immune defenses, and cope with mucociliary clearance mechanisms.
Despite advances in medicine and public health, respiratory pathogens are likely to remain a challenge in the future.