These organisms include non-hemolytic and alpha-hemolytic streptococci, some Neisseria species, staphylococci, diphtheria and hemophilus organisms, pneumococci, yeasts, and Gram-negative rods.
Gram-negative organisms are found more frequently in chronic mastoiditis, and in young infants, which may be due to prolonged antibiotic therapy.
Gram-negative organisms are responsible for many diseases, including gonorrhea, pertussis (whooping cough), salmonella poisoning, and cholera.
In particular, infants start with antibodies to viruses and gram-positive organisms, but not to gram-negative organisms.
UTIs in men are most likely to be caused by E. coli or another gram-negative bacterium.
Escherichia coli (E. coli) is another common gram-negative organism.