My throat culture & sensitivity c/s report says "organism: moderate growth streptococcus viridans group" is this normal, i've white coating on tongue?

Yes: This is a common organism for sore throat. Several antibiotics are effective for this.

Possible fungal...: Overgrowth. If you have cultures, you are probably already on an antibiotic for something. S. Viridens is a common oral bacteria that we all have on some level. Yours may be higher than normal but the white on your tongue could be candidiasis from a lack of "regular" bacteria that keep it down. Try 1/2 hydrogen peroxide/ 1/2 or mouthwash, brush your tongue, if no luck see a dr. May need nystatin.