Molecular analysis of mycobacteria isolated in Mexican patients with different immunodeficiencies in a tertiary care hospital.
OBJECTIVE
The prevalence of infections with Mycobacterium tuberculosis (MTB) and non-tuberculous mycobacteria (NTM) species in patients with immunodeficiencies in Mexico is unknown. The aim of this study was to identify, at the molecular level, the mycobacterial species most frequently affecting patients with immunodeficiencies and evaluate the genotypic diversity of MTB complex strains.


METHODS
We conducted a retrospective study of 97 strains in patients with the diagnosis of pulmonary (all isolates were of pathological significance) or extrapulmonary tuberculosis. PCR analysis was performed to determine whether they belonged to the MTB complex (MTC) or the Mycobacterium avium complex (MAC). Noncharacterized NTM were sequenced and, finally, MTC were genotyped by MIRUs-VNTR and spoligotyping.


RESULTS
Of the 97 mycobacterial strains isolated, 53% were M. tuberculosis, 10% M. bovis, 24% M. avium, 9% M. simiae, 2% M. kansasii and 2% M. gordonae. A great genetic diversity was found by MIRU-VNTR with the greatest polymorphism in MIRU 10, 16, 23 and 27. By spoligotyping, the predominant family was T1. Combining both methods, the association of 13 strains in four different groups was found.


CONCLUSIONS
This is the first molecular analysis of mycobacteria isolated from patients with immunodeficiencies in Mexico, describing the prevalence of different mycobacterial species in this population. A great genetic diversity of MTB strains was identified. This is also the first report in Mexico describing clinically important isolates of M. simiae.
Immunology and Infectious Disease Research Unit, Hospital de Infectología, Centro Médico Nacional La Raza (CMNR), Instituto Mexicano del Seguro Social (IMSS), Mexico City, Mexico.
Nancy
N
Cortés-Torres
Jorge A
JA
González-Y-Merchand
César
C
González-Bonilla
Guadalupe
G
García-Elorriaga
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D016867:Immunocompromised Host; D007153:Immunologic Deficiency Syndromes / Q000150:complications* / Q000276:immunology; D007223:Infant; D008297:Male; D008800:Mexico; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D016133:Polymerase Chain Reaction; D063128:Tertiary Health Care; D014376:Tuberculosis / Q000175:diagnosis* / Q000382:microbiology; D055815:Young Adult
Genotypification; MIRU; Molecular epidemiology; Spoligotyping