Those are opportunistic bacteria that can be secondary infections during a respiratory diseaseor air sacculitis. They (E.coli and Klebsiella) are both gram negative bacteria that Tylan would not treat. They are found in the bowel and Klebsiella is also common on skin. An antibiotic that would treat those might be Bactrim or Baytril, and Baytril is banned in layers, although some vets may still prescribe it. Your vet would be the one to ask about that.