Drug Resistance and Genotypes of Strains of Mycobacterium tuberculosis Isolated from Human Immunodeficiency Virus-infected and Non-infected Tuberculosis Patients in Bauru, São Paulo, Brazil

• Published in: Memórias do Instituto Oswaldo Cruz Vol. 97; no. 8
• Main Authors: Ida Maria Foschiani Dias Baptista, Maraníbia Cardoso Oelemann, Diltor Vladimir Araújo Opromolla, Philip Noel Suffys
• Format: Journal Article
• Language: English
• Published: Fundação Oswaldo Cruz, Fiocruz 03-02-2003
• Subjects: tuberculosis - transmission - drug resistance - fingerprinting - São Paulo - Brazil
• ISSN: 1678-8060

Little is known about transmission and drug resistance of tuberculosis
(TB) in Bauru, State of São Paulo. The objective of this study was
to evaluate risk factors for transmission of Mycobacterium tuberculosis
strains in this area. Strains were collected from patients attended
at ambulatory services in the region and susceptibility towards the
main first line antibiotics was determined and fingerprinting
performed. A total of 57 strains were submitted to susceptibility
testing: 23 (42.6%) were resistant to at least one drug while 3 (13%)
were resistant against both rifampicin and isoniazide. Resistant
strains had been isolated from patients that had not (n = 13) or had (n
= 9) previously been submitted to anti-TB treatment, demonstrating a
preoccupying high level of primary resistance in the context of the
study. All strains were submitted to IS6110 restriction fragment length
polymorphism (IS6110-RFLP) and double repetitive element PCR (DRE-PCR).
Using IS6110-RFLP, 26.3% of the strains were clustered and one cluster
of 3 patients included 2 HIV-infected individuals that had been
hospitalized together during 16 days; clustering of strains of patients
from the hospital was however not higher than that of patients attended
at health posts. According to DRE-PCR, 55.3% belonged to a cluster,
confirming the larger discriminatory power of IS6110-RFLP when compared
to DRE-PCR, that should therefore be used as a screening procedure
only. No clinical, epidemiological or microbiological characteristics
were associated with clustering so risk factors for transmission of TB
could not be defined in the present study.