Yes there are bacteriophages for both gram positive and for gram negative bacterium. But there are not any bacteriophages that could infect both. Bacteriophages are normally very genus or species specific.

Hi. Most bacteriophages are specific to a certain type of bacteria. And it is relatively rare for a phage to infect multiple types.

Niti Sarat Rhizobium (gram-negative host) phage RHph_N3_8 belongs to Caudoviricetes, phages that are common for gram-positive bacteria

each bacteria has special phage for it according to receptors on it .

each bacteria has special phage for it according to receptors on it .