What ingestion is likely responsible for a 3-month-old male presenting with constipation and flaccid paralysis?

The presentation of constipation and flaccid paralysis in a 3-month-old male is highly indicative of infant botulism, which is caused by the ingestion of botulinum spores. These spores produce a potent neurotoxin, leading to symptoms that can include muscle weakness, hypotonia, and gastrointestinal manifestations such as constipation.

Infant botulism typically occurs in infants younger than one year of age because their gastrointestinal tracts are not fully developed and lack sufficient normal flora to inhibit the growth of Clostridium botulinum. This organism can be ingested via spores found in certain environments and can proliferate in the intestines, releasing toxins that disrupt normal neuromuscular function.

While honey is commonly associated with infant botulism due to its potential to contain botulinum spores, the ingestion of the spores themselves is the critical factor leading to the clinical picture. Therefore, botulinum spores are the direct cause of the condition.

In contrast, peanut butter and infant formula are not typically associated with botulism or the specific symptoms presented in this case. Peanut butter is not recommended for infants due to potential allergenicity and choking hazards, while infant formula does not contain botulism spores and would not cause flaccid paralysis