Original ContributionsMoxifloxacin Use and Its Association on the Diagnosis of Pulmonary Tuberculosis in An Inner City Emergency Department

BackgroundMoxifloxacin can be used in the treatment of tuberculosis, its effect on the diagnosis and treatment of pulmonary tuberculosis is not well characterized.ObjectiveTo identify patients from the St. Paul's Hospital emergency department (ED) treated with moxifloxacin who also had sputum sent for investigation of possible tuberculosis and the impact on sensitivity of acid-fast bacilli (AFB) smears and time to initiation of tuberculosis treatment.MethodsWe conducted a retrospective single-center cohort study on patients that were prescribed moxifloxacin in the ED during a 5-year period and had samples collected for pulmonary tuberculosis. All AFB samples obtained throughout the hospital in patients not exposed to moxifloxacin during the same time period were also examined.ResultsTwo-thousand six hundred and seventy-three patients who were admitted to St. Paul's Hospital through the ED received moxifloxacin during the study period. 273 (10.2%) of these patients were subsequently investigated for tuberculosis, with 9 positive cases of Mycobacterium tuberculosis (3.3%). One-thousand three hundred and sixty-nine patients not exposed to moxifloxacin were screened for tuberculosis with 33 active cases (2.4%). The false-negative rate for AFB smears in the exposed group was 85.2% vs. 53.8% in the unexposed group (relative risk of false-negative AFB = 1.55; 95% CI 1.24-2.03). Time to initiation of anti-tuberculosis therapy was significantly delayed in the exposed group, with median time to initiation of 14 days vs. 2 days (p = 0.013).ConclusionsExposure to moxifloxacin is associated with significantly increased rates of false-negative AFB smears and was associated with a significant delay in the initiation of anti-tuberculosis therapy.