Method for detecting the presence of specific micro-organisms and device for the same

A method of testing for the presence of a target nucleic acid sequence, target protein or target antigen comprising the steps of:

• exposing nucleic acid sequences, proteins or antigens from a sample to a probe under hybridisation conditions;
• the probe comprising a first catalytic element or precursor thereof and a binding element capable of binding at least partially to the target nucleic acid sequence, target protein or target antigen;
• exposing the nucleic acid sequences, proteins or antigens to:
• identifiable marker elements;
• at least a first substrate, said substrate being capable of reaction with the first catalytic element;
• and a conversion substrate;
• under conditions which result in a physical change of the conversion substrate and the physical change causes the identifiable marker elements to be entrapped or otherwise retained against removal by washing, substantially in the vicinity of the probe;
• and,
• wherein the first catalytic element is a catalytic element that is capable of a turnover rate of greater than 3000 molecules per second.