The genus Listeria currently contains 10 species: L. fleischmannii, L. grayi, L. innocua, L. ivanovii, L. marthii, L. monocytogenes, L. rocourtiae, L. seeligeri, L. weihenstephanensis and L. welshimeri. L. dinitrificans, previously thought to be part of the Listeria genus, was reclassified into the new genus Jonesia.tudies suggest up to 10% of human gastrointestinal tracts may be colonized by L. monocytogenes. Nevertheless, clinical diseases due to L. monocytogenes are more frequently recognized by veterinarians, especially as meningoencephalitis in ruminants. See: listeriosis in animals.
1 Sweating/Irritation Interestingly, another forgotten cause of underarm pain is sweating. 2  Sweating itself doesn't lead to underarm pain, but what it does do is irritate the skin, which in turn can cause itching or burning that may result in pain.
The most common cause of an underarm lump is a localized infection in the breast, arm, or the armpit itself, such as folliculitis due to an infected hair follicle.Immune system disorders and some types of cancer, such as breast cancer, can also lead to an underarm lump due to swollen lymph nodes.nfectious causes of an underarm lump. An underarm lump caused by a bacterial infection can be associated with serious and potentially life-threatening complications if the infection is not treated promptly with antibiotics.