Abstract: Objective To investigate risk factors and pathogenic bacteria characteristics in the elderly with pulmonary tuberculosis complicated by hospital-acquired pneumonia(HAP).  Methods We analyzed retrospectively 140 the elderly patients with pulmonary tuberculosis complicated by HAP.  Results HAP was closely related with chronic pulmonary disease, cadio-cerebrovascular disease, diabetes mellitus, malignant tumor, malnutrition, using broad spectrum antibiotic, and hospitalization more than three weeks. The major pathogenic bacteria of HAP was gram negative bacilli.Klebsiella pneumoniaeandpseudomonas aeruginosawere the most common bacilli. Conclusion It is important for intervention of risk factors to control HAP in the elderly patients with pulmonary tuberculosis. The common pathogenic bacteria of HAP in the elderly patients with pulmonary tuberculosis is gram negative bacilli. Empirical therapy with antibiotics can be given according to the pathogenic bacteria characteristics before acquring Results of drug sensitivity test.

Key words: tuberculosis, pulmonary/complication, pneumonia, cross infection, risk factors