Outbreak of Multiresistant Tuberculosis

Abstract

Basis: Six cases of multiresistant tuberculosis diagnosed in the Hospital of Navarra in 1996 were studied. Material and methods: Sensitivity tests were carried out using the BACTEC 460TB system against four main anti-tuberculosis medicines: Isoniazid, Streptomycin, Rifampizin and Ethambutol. "Fingerprinting" techniques by means of RFLP with IS 6110 were used in the epidemiological study. Results: Four of the patients were also infected with HIV. All of them had a fatal short-term prognosis. These four showed resistance to the drugs under study; in three resistance was primary, and secondary in the fourth. The molecular study showed that three HIV+ patients had identical patterns of restriction fragment length polymorphism (RFLP). Two were brothers and nosocomial infection was demonstrated in the third. On the other hand, the RPLF pattern of these patients showed great similarity to that of one of the HIV- patients, which suggests a clone origin of the strains, no other epidemiological relationship being found. The RPLF pattern of the other HIV+ patient was identical to that of another of his strains, isolated 14 months before, with the first strain sensitive. The other two patients were HIV- women, and they evolved favourably. In one, who was diabetic, a multiresistant tuberculosis had been diagnosed 7 years before, remaining asymptomatic up until the present. The other involved a secondary resistance due to deficient treatment. Conclusions: The appearance of multiresistant tuberculosis is a very serious problem amongst HIV+ patients, especially at a time when their life expectancy has improved considerably due to the new therapies. In HIV- patients, multiresistant tuberculosis has a better prognosis. Typification by means of restriction fragment length polymorphism is very useful in clarifying the origin of the cases.