Toxins produced, especially by bacterial or fungal cells, and released into the culture medium or environment. ... (12 Dec 1998) ... 
Poisonous substances produced by the microbial cell and liberated into the surrounding environment, without destruction of the cell.Toxins released from Gram positive and Gram negative bacteria - as opposed to endotoxins that form part of the cell wall. Examples are cholera, pertussis and diphtheria toxins. Usually specific and highly toxic. See Table E2.