Table 4.

Examples of associations between some histo-blood group phenotypes and microorganisms.

Microorganisms	Histo-blood group phenotypes	Biological effects
Gastrointestinal tract
Helicobacter pylori	O, Le(a−b+)	Peptic ulcers, Gastritis
Escherichia coli	B	Gastrointestinal infection
Giardia lamblia	A	Re-infestation
Toxoplasma gondii	B	Not determined
Candida albicans	O, non-secretor	Gastric inflammation
Vibrio cholera	O, Le(a+b−)	Severe diarrhea
Salmonella typhimurium	B	Typhoid fever
Norovirus	Non-secretor	Gastroenteritis
Respiratory tract
Streptococcus pneumoniae	A and O	Pneumonia
Streptococcus pyogenes	A, non-secretor	Rheumatic fever
Influenza A	O	Influenza
Mycobacterium tuberculosis	O	Tuberculosis
Genitourinary tract
Escherichia coli	A, B, Le(a+b−)	Urinary infection
Pseudomonas aeruginosa	B	Upper urinary infection
Neisseria gonorrhoeae	B	Urethral infection

Source: Adapted from Blackwell et al.⁴⁴