Adult-infant botulism

Adult botulism is a very rare syndrome and its etiology is similar to infant botulism. 

Gastrointestinal colonization in adults or children by clostridial bacteria does not typically take place except under circumstances where the normal flora has been altered by antibiotic treatment (Cheiington, 1998). Botulism results from in vivo production of toxin, analogous to the pathogenesis of infant botulism (McCroskey and Hatheway, 1988 Chia et al, 1986). Support for this form of botulism is provided by demonstration of prolonged excretion of toxin and C. botulinum in stool and/or by the demonstration of C. botulinum spores but not preformed toxin in suspected foods. 

Under rare conditions, adults may manifest a syndrome similar to that of infant botulism. Such cases generally occur in hospitalized patients treated with a long course of multiple antibiotics that eliminate the normally suppressive intestinal flora other predisposing factors include inflammatory bowel disease and surgical alterations of the bowel (Fenicia et al., 1999). 

In adults, botulinum intoxication generally results from ingestion of preformed toxin elaborated in contaminated foods (foodbome), or from colonization by Clostridium botulinum of deep wounds with subsequent production of toxin (wound botulism). A third form, termed infant botulism, is observed in young infants and originates from colonization of the large intestine by Clostridium botulinum with subsequent production and absorption of toxin. Rarely, adults also exhibit a syndrome resembling infant botulism and some authors regard this as the fourth manifestation of botulism. ... 

One other mode of botulinum toxin poisoning has a significant number of cases in the United States infant botulism.1 These cases involve an ongoing colonization of the intestines of infants, usually in the first year of life, by the usually benign C botulinum organism. Apparently, the flora of newborns, their intestinal environment, or both is such that the organism can grow and produce toxin there are no well-documented cases of intestinal infections in adult humans. 

It may not be wise to feed honey to infants under 1 year of age, since infant botulism— botulism resulting from the production of toxins after the ingestion of Colostridium botuli-num—may result from the ingestion of raw agricultural products. Honey has been implicated as a source in a very few cases. This type of botulism does not occur in older children and adults. 

Spores of Clostridium botulinum, responsible for infant botulism, are often contained in honey, which may germinate in adults without adverse effects, but may cause serious illness in infants. In 1976, of 43 cases of infant botulism in California, 13 involved honey (C. botulinum found in 13% of 60 tested samples). It has been recommended that honey not be given to infants under 1 year old. ... 

Ingestion is the primary exposure pathway for botulism. Wound botulism occurs when the bacterium encounters devitalized human tissue, synthesizes toxin, and thus causes disease. Intestinal (adult and infant types) botulism involves ingestion of spores or the live bacterium and, due to impaired intrinsic defenses, the gastrointestinal tract becomes colonized with Clostridium botulinum. In infant type, the mucosal surface of the intestines is susceptible to colonization due to multiple factors including decreased acidity of the stomach and lack of bile of acids, which are natural barriers. In adult-type intestinal botulism, patients have had surgical vagotomy/... 

Two types of illness are associated with the botulinum toxin, infant and adult botulism. An adult becomes iU by eating spoiled food that contains the toxin. Infants become ill from eating the spores of the botulinum bacterium. One source of these spores comes from the ingestion of honey. Spores are not normally toxic to adults. Botulinum toxins work by binding to the presynaptic nerve terminal at the neuromuscular junction and at cholinergic autononuc sites. They then act to stop the release of acetylchloline presynaptically, thus blocking neurotransmission. 

---