Outbreak of multiple drug-resistant tuberculosis in Lisbon: detection by restriction fragment length polymorphism analysis.
METHODS
Multidrug-resistant tuberculosis (MDR-TB) mainly among human immunodeficiency virus (HIV) seropositive patients in Lisbon hospitals in 1996-1997.


OBJECTIVE
Detection of transmission of MDR-TB strains and epidemic outbreaks in several hospital units in the city of Lisbon, including a prison hospital.


METHODS
Use of restriction fragment length polymorphism (RFLP) to fingerprint isolates of Mycobacterium tuberculosis resistant to isoniazid, rifampicin, and one other drug.


RESULTS
A total of 43 MDR-TB strains were typed. Sixty-seven per cent of the patients were HIV positive, 12% were HIV negative, and the remainder had unknown HIV status. About 88% of the isolates were grouped in three genetically similar clusters, suggesting possible recent transmission. A predominant cluster (cluster A), corresponding to 72% of the cases, was found, 45% of which came from the prison hospital. Strains from this cluster were resistant to isoniazid, rifampicin, streptomycin, and sometimes ethambutol. A retrospective epidemiological investigation was conducted with respect to all patients in cluster A, and epidemiological links were established between them.


CONCLUSIONS
Our results suggest recent transmission of MDR-TB, mainly in HIV-positive patients, in Lisbon hospitals. Moreover, the predominant MDR-TB clustered strains were not confined to HIV-infected individuals, as they were also isolated in some immunocompetent patients.
Portugal
I
I
Departamento de Microbiologia, Faculdade de Farmácia de Universidade de Lisboa, Portugal. isabel.portugal@ff.ul.pt
Covas
M J
MJ
Brum
L
L
Viveiros
M
M
Ferrinho
P
P
Moniz-Pereira
J
J
David
H
H
D016000:Cluster Analysis; D004196:Disease Outbreaks; D004352:Drug Resistance, Microbial; D015658:HIV Infections / Q000150:complications; D006801:Humans; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification*; D012150:Polymorphism, Restriction Fragment Length; D011174:Portugal / Q000453:epidemiology; D018088:Tuberculosis, Multidrug-Resistant / Q000150:complications / Q000453:epidemiology* / Q000235:genetics / Q000635:transmission