Oligonucleotide-based probes for detection of bacterial nucleases

The present invention relates to a rapid detection of microbial-associated nuclease activity with chemically modified nuclease (e.g., ribonuclease) substrates, and probes and compositions useful in detection assays. Accordingly, in certain embodiments, the present invention provides a probe for detecting a microbial endonuclease comprising a substrate oligonucleotide of 2-30 nucleotides in length, a fluorescence-reporter group operably linked to the oligonucleotide, and a fluorescence-quencher group operably linked to the oligonucleotide. The fluorescence-reporter group and the fluorescence-quencher group are separated by at least one RNAse-cleavable residue, e.g., RNA base.