<prompt> Post traumatic osteomyelitis causing organism isStaphylococcus aureusStaphylococcus pyogenesE.coliPseudomonas  <response>: Staphylococcus aureus is the most common causative organism in all age groups. Salmonella is the commonest organism in sickle cell anemia patientsdiaphyseal. Psuedomonas aeruginosa is the commonest organism in drug abusers. ref : maheswari 9th ed 