title: A population-based study of first and second-line drug-resistant tuberculosis in a high-burden area of the Mexico/United States border.
abstract: The resistance of 139 Mycobacterium tuberculosis (MTB) isolates from the city of Monterrey, Northeast Mexico, to first and second-line anti-TB drugs was analysed. A total of 73 isolates were susceptible and 66 were resistant to anti-TB drugs. Monoresistance to streptomycin, isoniazid (INH) and ethambutol was observed in 29 cases. Resistance to INH was found in 52 cases and in 29 cases INH resistance was combined with resistance to two or three drugs. A total of 24 isolates were multidrug-resistant (MDR) resistant to at least INH and rifampicin and 11 MDR cases were resistant to five drugs. The proportion of MDR-TB among new TB cases in our target population was 0.72% (1/139 cases). The proportion of MDR-TB among previously treated cases was 25.18% (35/139 cases). The 13 polyresistant and 24 MDR isolates were assayed against the following seven second-line drugs: amikacin (AMK), kanamycin (KAN), capreomycin (CAP), clofazimine (CLF), ethionamide (ETH), ofloxacin (OFL) and cycloserine (CLS). Resistance to CLF, OFL or CLS was not observed. Resistance was detected to ETH (10.80%) and to AMK (2.70%), KAN (2.70%) and CAP (2.70%). One isolate of MDR with primary resistance was also resistant to three second-line drugs. Monterrey has a high prevalence of MDR-TB among previously treated cases and extensively drug-resistant-MTB strains may soon appear.
authors.affiliation: División de Biología Celular y Molecular, Centro de Investigación Biomédica del Noreste, Instituto Mexicano del Seguro Social, Monterrey, Nuevo León, México.
authors.forename: Pola
authors.initials: P
authors.lastname: Becerril-Montes
authors.forename: Salvador
authors.initials: S
authors.lastname: Said-Fernández
authors.forename: Julieta
authors.initials: J
authors.lastname: Luna-Herrera
authors.forename: Guillermo
authors.initials: G
authors.lastname: Caballero-Olín
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Enciso-Moreno
authors.forename: Herminia Guadalupe
authors.initials: HG
authors.lastname: Martínez-Rodríguez
authors.forename: Gerardo
authors.initials: G
authors.lastname: Padilla-Rivas
authors.forename: Elsa
authors.initials: E
authors.lastname: Nancy-Garza-Treviño
authors.forename: Gloria María
authors.initials: GM
authors.lastname: Molina-Salinas
mesh_terms: D000293:Adolescent; D000328:Adult; D000995:Antitubercular Agents / Q000494:pharmacology*; D005260:Female; D062306:Geography, Medical; D006801:Humans; D008297:Male; D008800:Mexico / Q000453:epidemiology; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000187:drug effects*; D012307:Risk Factors; D012959:Socioeconomic Factors; D018088:Tuberculosis, Multidrug-Resistant / Q000453:epidemiology / Q000382:microbiology*; D014397:Tuberculosis, Pulmonary / Q000453:epidemiology / Q000382:microbiology*; D055815:Young Adult
chemical_list: D000995:Antitubercular Agents