The present invention relates to a method for detecting bacteriolytic conditions in a test sample comprising the step of contacting the test sample with a bacterial strain and a substrate which undergoes a detectable change when cleaved by a specific enzyme of said bacterial strain, wherein the bacterial strain is unable of: (a) uptaking the substrate from the medium and (b) secreting the enzyme specific for the substrate outside of the cell and wherein detecting a change in the test sample due to the cleavage of the substrate by its specific bacterial enzyme indicates that bacteriolytic conditions exist in the test sample. The invention further provides a kit for performing the method of the invention.