After B.Sc in Microbiology, you can look for M.Sc degree in the same stream. M.Sc degree can be selected in subjects of Clinical Microbiology, Industrial Microbiology, or Medical Microbiology. PG Diploma in Microbiology can be pursued. MCA is a good option for candidates interested in software field. You can try for MBA or MFA if you are interested to have a job in management.
MBA will be a good choice if you want to come out of your field.

If you want to go on in your field, then you can opt for any of the following courses
M.Sc in Medical Microbiology
M.Sc in Clinical Microbiology
M.Sc in Cell Biology
M.Sc in Genetics
M.Sc in Biotechnology etc.