Which pathogen is known to cause cold agglutinins?

Cold agglutinins are antibodies that agglutinate red blood cells at lower temperatures, typically associated with certain infections. Mycoplasma pneumoniae is the organism primarily linked with cold agglutinin production. This bacterium is a common cause of atypical pneumonia, particularly in young adults, and it can trigger an immune response that includes the formation of cold agglutinins, which are usually IgM antibodies directed against red blood cell antigens. These antibodies can lead to hemolytic anemia, characterized by an increase in cold agglutinins in the serum during infection.

The other pathogens listed do not typically cause cold agglutination. Streptococcus pneumoniae is known for causing pneumonia and other respiratory infections but is not associated with cold agglutinin production. Escherichia coli and Neisseria meningitidis are associated with different clinical presentations and do not have a known association with the specific production of cold agglutinins. Thus, Mycoplasma pneumoniae is uniquely recognized for its role in this phenomenon.