Which of the following is a characteristic of Strep pneumoniae?

Streptococcus pneumoniae, commonly known as pneumococcus, is indeed a major cause of bacterial pneumonia. This characteristic is particularly important because it highlights the bacterium's role in respiratory infections, especially among vulnerable populations such as children and the elderly. The organism can lead to various types of pneumonia, notably lobar pneumonia, and is associated with increased morbidity and mortality rates in affected individuals.

Recognizing S. pneumoniae as a common cause of pneumonia assists in guiding appropriate treatment and management strategies in clinical settings. Additionally, it underscores the importance of vaccination, as pneumococcal vaccines are available to help prevent infections caused by this bacteria.

Other options, while they contain some truth, do not specifically exemplify the defining characteristics of S. pneumoniae to the same extent as its role in pneumonia. For instance, while resistance to penicillin has been noted in some strains, it is not a universal trait. Similarly, although S. pneumoniae can cause meningitis, it is not exclusively recognized for that reason compared to pneumonia. Lastly, the transmission route via contaminated water is more relevant to other pathogens, not S. pneumoniae. Hence, associating this bacterium primarily with pneumonia is substantiated by its epidemiology and clinical significance.