A method for isolating microorganisms from a sample, the sample including sample matrix and microorganisms, the method including the steps of providing a receptacle, the receptacle configured to allow filtering of the sample and to reversibly contain the sample and a concentration agent; adding the sample to the receptacle, wherein a microorganism-bound composition will be formed in the receptacle, the microorganism-bound composition including concentration agent-bound microorganisms and sample matrix; and filtering the microorganism-bound composition through a filter to collect the concentration agent-bound microorganisms on the filter, wherein the filter has an average pore size that is greater than the average size of the microorganisms. Kits and systems are also disclosed herein.