Nosocomial transmission of tuberculosis in two hospitals for mentally handicapped patients.

Background/purpose: An unexpected significant increase in the number of tuberculosis (TB) cases in one hospital for mentally handicapped patients in eastern Taiwan was observed in early 2002. An active screening program was performed to identify undetected TB cases and to investigate nosocomial transmission of TB in two hospitals for mentally handicapped patients in eastern Taiwan.

Methods: Active chest X-ray (CXR) screening followed by passive symptom screening were used to identify patients with pulmonary TB over 2 years in hospital A and B. IS 6110 restriction fragment length polymorphism and spacer oligonucleotide typing (spoligotyping) profiles of the isolates, clinical record of each case, TB control policies of the two hospitals, and risk factors of nosocomial transmission were analyzed.

Results: A total of 94.8% (2298/2423) inmates in hospital A and 96.3% (1902/1975) inmates in hospital B were screened by CXR at the beginning of 2002. During the 2-year study period, TB was diagnosed by sputum cultures for 30 patients in hospital A (notified disease rate = 619 per 100,000 population per year) and eight patients in hospital B (notified disease rate = 203 per 100,000 population per year). Seventeen patients (56.7%) in hospital A had six cluster pattern strains, and none did in hospital B, which highlighted the importance of immediate expert consultation and thorough isolation of TB suspects.

Conclusion: This is the first study to prove that thorough isolation by referring patients to general hospital as soon as possible could decrease nosocomial transmission of TB in hospitals for mentally handicapped patients. Routine CXR screening at admission and maintaining a high alert for TB in daily practice are essential.