To do MD in pathology, you must have to complete MBBS first, as the basic eligibility criteria says that for doing MD or MS, you need to complete MBBS from an recognized institute. So after completing BSc Microbiology, you cannot do MD pathology. But surely, you can go for Master's in Science or MSc. There are various specializations available in MSc, like Applied Microbiology, Industrial Microbiology, Medical Microbiology, Molecular Biology etc. Various job opportunities are there once you complete your Master's. You can find jobs in sectors like Pharmaceutical Companies, Chemical Workshops, Food Industry, Laboratories, Research Labs, Private Clinics etc. After completing MSc, you can go for PhD as Microbiology has many things in Research field.