Meningitis, Pneumonia, Tetanus, Typhoid: All are bacterial diseases.
Causative agent of meningitis is Neisseria meningitidus (Bacteria).
Causative agent of pneumonia is Diplococcus pneumoniae (Bacteria).
Causative agent of tetanus is Clostridium tetani (Bacteria).
Causative agent of typhoid is Salmonella typhi (Bacteria).