A new family of contrast agents that sneak into bacteria disguised as glucose food can detect bacterial infections in animals with high sensitivity and specificity. These agents – called maltodextrin-based imaging probes – can also distinguish a bacterial infection from other inflammatory conditions. Maltodextrin-based imaging probes consist of a fluorescent dye linked to maltohexaose, which is a major source of glucose for bacteria. The probes deliver the contrast agent into bacteria through the organism's maltodextrin transporter, which only exists in bacterial cells and not mammalian cells, and become concentrated within the bacteria.