The present invention relates to a genetically-engineered Mycobacterium strain and a use thereof in the preparation of steroidal compounds. The genetically-engineered Mycobacterium strain is a Mycobacteria which lacks of acyl-CoA dehydrogenase genes fadE31, fadE32 and fadE33, wherein acyl-CoA dehydrogenase genes fadE31, fadE32 and fadE33 respectively encode proteins as follows: having amino acid sequences according to SEQ ID NOs 4, 6 and 8; derived by substituting, deleting or inserting one or more amino acids in the amino acid sequence defined by preceding protein and having the same function as that of the preceding protein. The present invention constructs a genetically-engineered Mycobacterium strain and applies it in preparing steroidal compounds, thereby enriching the types of valuable intermediates, improving the production efficiency and product quality of steroid drugs, reducing energy consumption in the steroid drugs production, simplifying production steps, and reducing production costs.

The present invention relates to a genetically-engineered Mycobacterium strain and a use thereof in the preparation of steroidal compounds. The genetically-engineered Mycobacterium strain is a Mycobacteria which lacks of acyl-CoA dehydrogenase genes fadE31, fadE32 and fadE33, wherein acyl-CoA dehydrogenase genes fadE31, fadE32 and fadE33 respectively encode proteins as follows: having amino acid sequences according to SEQ ID NOs 4, 6 and 8; derived by substituting, deleting or inserting one or more amino acids in the amino acid sequence defined by preceding protein and having the same function as that of the preceding protein. The present invention constructs a genetically-engineered Mycobacterium strain and applies it in preparing steroidal compounds, thereby enriching the types of valuable intermediates, improving the production efficiency and product quality of steroid drugs, reducing energy consumption in the steroid drugs production, simplifying production steps, and reducing production costs.

A recombinant Mycobacterium strain co-expressing MIF and IL-7, and a composition containing the strain as an active ingredient are disclosed. The strain and the composition are suitable for preventing or treating cancer. The strain induces a maximized anticancer immune response by stably expressing MIF and IL-7 through a mycobacteria-derived replicable plasmid, such as a pMyong2 shuttle vector. Accordingly, the strain and the composition may be usefully used as an efficient anticancer live vaccine composition that induces multiple cellular and humoral immune responses through single administration of the recombinant strain.

Provided herein is a rapid amplifiable readout of bacterial growth, such as an ELISA paired with metabolic labeling. Methods comprise a) contacting a sample from a subject suffering from a bacterial infection with an antibiotic; and b) determining the effect, if any, of the antibiotic on incorporation of a single- or di-D-amino acid into peptidoglycan of the bacterial cell or incorporation of trehalose into the bacterial cell envelope, wherein an antibiotic that reduces, as compared to control without the antibiotic being present, incorporation of the D-amino acid into peptidoglycan of the bacterial cell or inhibited incorporation of trehalose into the bacterial cell envelope is an antibiotic that is effective.

Isolated mutant Mycobacterium tuberculosis bacteria comprising a deletion in the ESAT-6 gene cluster region 3 (esx-3 region) are provided, as well as compositions comprising such, methods of production thereof and methods of use thereof.