A diagnosis of pneumonia was made when there were symptoms of lower respiratory tract infections (e.g., cough, purulent expectoration, chest pain) and pulmonary infiltrates on the chest radiograph not attributable to other causes, coinciding with the isolation of the same isolate in sputum, bronchoalveolar lavage fluid, or appropriate respiratory
specimens as the ESBL producer isolated from blood samples. For those with more than one episode of bacteremia caused by the same isolate, only the first episode was included for analysis.