A filter medium capable of removing microorganisms from a fluid such as water. The filter medium includes particles of activated carbon, particles of a substantially insoluble inorganic material having an isoelectric point greater than the fluid being filtered. A low melt index binder, preferably with a melt index of less than about 1 gram per 10 minutes, binds the particles of activated carbon and particles of inorganic material, such that the binder will become tacky at elevated temperatures without becoming sufficiently liquid to substantially wet the particles of activated carbon and inorganic material. An antimicrobial material can be incorporated into the filter to prevent biofilm growth. The use of a biocidal material in combination with the high isoelectric point material provides a trap-and-kill mechanism for microorganism removal.