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September 20-21, 2017 | Philadelphia, USA
Global summit on
TUBERCULOSIS AND LUNG DISEASE
Int J Respir Med 2017 Volume 2 Issue 2
Molecular epidemiology in Chile: First confirmed study of cross-contamination of
Mycobacterium
tuberculosis
through MIRU-VNTR15 in a regional laboratory
Karla Kohan-Ivani, Álvaro Díaz B, Tamara Leiva C, Jaime Lagos B, Marcos Gallardo M, Jorge Fernández Ó
and
Fabiola Arias M
Instituto de Salud Pública, Chile
T
uberculosis is one of the main causes of mortality of
infectious disease in the world. Chile is considered a
low incidence country and maintains an active surveillance
through the National Tuberculosis Control Program (NTCP).
The tuberculosis diagnosis in clinical laboratories requires
qualified equipment and personnel in microbiology
techniques. The increase of performed samples, in certain
periods of time, might exceed the capacity of some
laboratories, added to, due to bad microbiological practices,
may produce false positive results by cross-contamination
cases. This study details the confirmation process of a
cross-contamination case detected in a regional laboratory
in Chile. A group of 31 strains identified as
Mycobacterium
tuberculosis
by line probe assay (LPA), from patients’ samples
with negative baciloscopy and positive culture, which had a
low count of colonies, were studied. Those samples were
processed in the same period by the same operator in a
regional laboratory. The study included cultures with (+)
to (+++) bacilloscopic results, since they could correspond
to a contamination source. The suspicious strains were
sent to the Chilean Tuberculosis Reference Laboratory
and analyzed by MIRU-VNTR15. The MIRU-VNTR15 assay
showed 4 different genetic patterns among the 31 strains.
Two pairs of patients were related to each other, while the
rest of them had not epidemiological connection. MIRU-
types results, including the patients’ epidemiological
backgrounds analysis, allowed the first confirmation case of
cross-contamination in the country. A direct supervision to
the regional laboratory was needed to train and implement
corrective actions to the laboratory staff. In this way, the
molecular and epidemiological analysis as well as the direct
supervision enabled the definition and implementation of
a surveillance strategy to detect an early, suspicious, cross-
contamination case in the country, furthermore determine
the follow-up actions to the clinic and epidemiological
control of the involved patients.
Speaker Biography
Karla Kohan-Ivani has completed her PhD from Universidad de Chile, Chile. She is a
part of the professional staff of the Chilean Tuberculosis Reference Laboratory as the
Molecular Epidemiology Laboratory’s Manager.
e:
kkohan@ispch.cl