Thanks for posting your query.
Let me explain your query one by one.
As such there is no term regarding "minimal PTB". If you are suffering from PTB then it should be considered seriously as untreated PTB may spread to any organ of your body.
Saliva is never checked for PTB; its sputum which gets examined by specialized doctors.
Patients who have negative sputum for AFB is less infectious as compared to sputum positive AFB.
You should go for complete hemogram and ESR
for better clarification.
You should consult with internal medicine specialist/ chest physician and should go for treatment for 6 months.
Dr. Mayank Bhargava