There are also more unusual bacteria like mycoplasma pneumoniae, chlamydophila pneumoniae, and legionella pneumophila, which don't have a cell wall and are well known for causing an " atypical or walking pneumonia" because they often cause vague symptoms like fatigue.

还有一些更不寻常的细菌，如肺炎支原体、肺炎衣原体以及嗜肺军团菌，它们没有细胞壁，且因引起“非典型肺炎”而臭名昭着，因为它们通常会引起一些模糊的症状，如疲劳。