This would also increase the number of Staphylococcus relative to other bacteria in the ground. And these bacteria can transfer DNA to each other, including resistance genes. So many of your added bacteria would turn into MRSA, and if there is enough antibiotics in the environment to maintain the MRSA prevalence without your intervention, then you just might end up increasing the amount of MRSA in the region.
This would also increase the number of Staphylococcus relative to other bacteria in the ground. And these bacteria can transfer DNA to each other, including resistance genes. So many of your added bacteria would turn into MRSA, and if there is enough antibiotics in the environment to maintain the MRSA prevalence without your intervention, then you just might end up increasing the amount of MRSA in the region.