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Identification of an IS6110-like insertion sequence in M. avium subsp. hominissuis: significance and perspectives in the diagnosis of bovine tuberculosis

Poster presented in Seventh International Conference on Mycobacterium bovis

June 7th, 2022

Lorente-Leal V., Moya N., Munoz M., Romero B. and de Juan L.

The IS6110 element is commonly used for the detection of Mycobacterium tuberculosis complex (MTBC) DNA in human and veterinary samples. During the validation of a real-time PCR targeting this mobile genetic element, cross-reactivity against one ‘Mycobacterium avium subsp. hominissuis’ (MAH) isolate was detected (Lorente-Leal et al., 2021). Due to the extended use of this mobile element in the diagnosis of bovine tuberculosis, this phenomenon was evaluated further. The cross-reacting MAH strain was analysed through Whole Genome Sequencing. To assess the extension and significance of this interference, a selection of MAH isolates obtained from 124 herds in a Spanish region with very low bovine tuberculosis herd prevalence (0.05% in 2018) were analysed with the IS6110 Real-Time PCR.
Genomic data revealed a truncated IS6110-like element, 1245 bp long and 83% similar to the IS6110 from M. tuberculosis. This IS6110-like element was deemed inactive due to an incomplete 3’-extreme and a 5-bp long insertion in the Left Inverted Repeat. Sequences with 100% coverage and identity were detected in other MAH strains and two other M. avium complex species (M. bouchedurhonense and M. timonense). Seventy-four percent (92/124) of the MAH isolates were positive to this PCR, suggesting that, although it was frequently found in the selected sample population, it was not conserved in all MAH strains.
This study describes for the first time the existence of an IS6110-like element in certain MAC species and suggests the occurrence of previous DNA exchange with MTBC. Although the IS6110 real-time PCR offers very good diagnostic performance, the use of the IS6110 element, or any other transposable sequence, should be considered strategically taking into account the epidemiological situation and the prevalence of bTB in the region. The use of additional markers, such as mpb70 or MAC-specific targets, could be of special interest to increase the specificity of real-time PCR detection of bTB in low prevalence settings (e.g. < 1% in Spain) or in herds with a history of non-tuberculous mycobacteria isolation




Participants:

Universidad ComplutenseServicio de Micobacterias (MYC). Centro de Vigilancia Sanitaria Veterinaria (VISAVET). Universidad Complutense (UCM).

Universidad ComplutenseDepartamento de Sanidad Animal. Facultad de Veterinaria. Universidad Complutense (UCM).

Xunta de GaliciaServicio de Sanidad Animal. Consellería do Medio Rural. Xunta de Galicia.


Link to Seventh International Conference on Mycobacterium bovis





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Seventh International Conference on Mycobacterium bovis


Seventh International Conference on Mycobacterium bovis
Jun 7th-10th, 2022
Galway
Ireland

TITLE: Identification of an IS6110-like insertion sequence in M. avium subsp. hominissuis: significance and perspectives in the diagnosis of bovine tuberculosis


TYPE: Poster communication


AUTHORS: Lorente-Leal V., Moya N., Munoz M., Romero B. and de Juan L.


VISAVET PARTICIPANTS


First
Victor Lorente Leal
2nd
Nuria Moya Álvarez
4th
Beatriz Romero Martínez
Last
Lucía de Juan Ferré

DATE: June 7th, 2022


CITE THIS COMMUNICATION:

Lorente-Leal V., Moya N., Munoz M., Romero B. and de Juan L. Identification of an IS6110-like insertion sequence in M. avium subsp. hominissuis: significance and perspectives in the diagnosis of bovine tuberculosis. Seventh International Conference on Mycobacterium bovis, University College Dublin, Galway, Ireland, June 7th, 2022. (Poster communication)


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