This is a lobar pneumonia in which consolidation of the entire left upper lobe has occurred. This pattern is much less common than the bronchopneumonia pattern. In part, this is due to the fact that most lobar pneumonias are due to Streptococcus pneumoniae (pneumococcus) and for decades, these have responded well to penicillin therapy so that advanced, severe cases are not seen as frequently. However, pneumoccoci, like most other bacteria, are developing more resistance to antibiotics. Severe pneumococcal pneumonia still occurs, even in young to middle aged persons (not just the very young and the very old) and has a mortality rate of 20%!