I've found an old paper using radioactively labeled bacteria to track itstheir fate in macrophages. According to the data, both C$^{14}$C and P$^{32}$P are reutilized in the host cell.
COHN ZA. (1963). The fate of bacteria within phagocytic cells. I. The degradation of isotopically labeled bacteria by polymorphonuclear leucocytes and macrophages. J Exp Med. Jan 1;117:27-42.