title: [Nested-PCR for gene that encodes the antigen b applied to the diagnosis of pulmonary tuberculosis].
abstract: The polymerase chain reaction used for amplifying an internal sequence of a previously amplified fragment (nested-PCR) was investigated as a complementary alternative for searching for alcohol-acid resistant bacilli and Mycobacterium tuberculosis cultures in Lowenstein-Jensen medium. 144 sputum samples were investigated from patients with suspected tuberculosis that were sent to the Tuberculosis Laboratory of the Evandro Chagas Institute in Belém, between June 2002 and December 2003. From the 144 samples, 121 were characterized as tuberculosis: 119 were positive in cultures, 95 under bacilloscopy and 128 using nested-PCR. The sensibility of the nested-PCR was 96% (116/121), while the specificity was 48% (11/23). Nested-PCR may be a complementary tool for diagnosing tuberculosis, since it presents sensitivity equivalent to that of cultures. However, further evaluations are needed with the aim of minimizing the number of false-positive results.
authors.affiliation: Instituto Evandro Chagas, Belém, PA. karlalima@iec.pa.gov.br
authors.forename: Karla Valéria Batista
authors.initials: KV
authors.lastname: Lima
authors.forename: Maria Luíza
authors.initials: ML
authors.lastname: Lopes
authors.forename: Edvaldo Carlos Brito
authors.initials: EC
authors.lastname: Loureiro
authors.forename: Maurimélia Mesquita
authors.initials: MM
authors.lastname: Costa
authors.forename: Ninarosa Calzavara
authors.initials: NC
authors.lastname: Cardoso
authors.forename: George Leandro Ferreira
authors.initials: GL
authors.lastname: Lima
authors.forename: Maísa Silva
authors.initials: MS
authors.lastname: Sousa
mesh_terms: D000942:Antigens, Bacterial / Q000235:genetics*; D004269:DNA, Bacterial / Q000032:analysis; D005188:False Negative Reactions; D006801:Humans; D009169:Mycobacterium tuberculosis / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity; D013183:Sputum / Q000382:microbiology; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis*
chemical_list: D000942:Antigens, Bacterial; D004269:DNA, Bacterial; C065517:protein antigen b, Mycobacterium