Spot sputum screening: evaluation of an intervention in two homeless shelters

SETTING: Two homeless shelters in Birmingham, Alabama. OBJECTIVE: To interrupt tuberculosis transmission and evaluate the utility of spot sputum screening. DESIGN: Two shelters participated in the study between May 1996 and Februar y 1997. A spot sputum specimen was collected on a given evening from each o vernight client. Information was obtained regarding symptoms and tuberculin skin test (TST) status. There were four screenings during two rounds, with TST in round one only. RESULTS: Of 127 persons involved in the study, 120 (95%) provided specimens , and four tuberculosis cases were identified (4/127, 3.1%). Symptoms were infrequently reported. RFLP analysis (IS6110) confirmed a two-band cluster in three of the four cases; another matching two-band strain was found in a drug rehabilitation client staying in one shelter. Secondary RFLP typing ( pTBN12) confirmed the homeless cluster. Costs were $1311 per case identifie d. Among 92 clients with a prior TST, 40% reported a positive result (37/92 ). Of 21 PPD tests read, 11 were greater than or equal to 10 mm (52%). CONCLUSION: Spot sputum screening is effective in identifying unsuspected t uberculosis cases in shelters. It has acceptable costs, is logistically sim ple and efficient. Symptom screening was not useful in this general homeles s population. RFLP analysis showed cloning of the two-band strain. Given th e evidence for ongoing transmission, sputum screening should be considered in shelter settings.