Molecular typing of Mycobacterium bovis strains isolated in Italy from 2000 to 2006 and evaluation of variable-number tandem repeats for geographically optimized genotyping.
Spoligotyping and exact tandem repeat (ETR) analysis of Mycobacterium bovis and M. caprae isolated strains has been routinely carried out in Italy since 2000 to obtain a database of genetic profiles and support traditional epidemiological investigations. In this study, we characterized 1,503 M. bovis and 57 M. caprae isolates obtained from 2000 to 2006 in 747 cattle herds mainly located in northern Italy. We identified 81 spoligotypes and 113 ETR profiles, while the combination of spoligotyping/ETR analysis differentiated 228 genotypes, with genotypic diversity indices of 0.70 (spoligotyping), 0.94 (ETR-A to -E typing), and 0.97 (spoligotyping/ETR-A to -E typing), respectively. Despite the high degree of resolution obtained, the spoligotyping/ETR methods were not discriminative enough in the case of genotypes characterized by the combination of SB0120, the predominant spoligotype in Italy, with the most common ETR profiles. To obtain a more informative subset of typing loci, 24 mycobacterial interspersed repetitive unit-variable-number tandem repeat (MIRU-VNTR) markers were evaluated by analyzing a panel of 100 epidemiologically unrelated SB0120 isolates. The panel was differentiated into 89 profiles with an overall genotypic diversity of 0.987 that could be also achieved by using a minimal group of 13 loci: ETR-A, -B, and -E; MIRU 26 and 40; and VNTR 2163a, 2163b, 3155, 1612, 4052, 1895, 3232, and 3336. The allelic diversity index and the stability of single loci was evaluated to provide the most discriminative genotyping method for locally prevalent strains.
Boniotti
M Beatrice
MB
Centro Nazionale di Referenza per la Tubercolosi Bovina, Istituto Zooprofilattico Sperimentale Lombardia e Emilia-Romagna, Via Bianchi 9, 25124 Brescia, Italy. mariabeatrice.boniotti@bs.izs.it
Goria
Maria
M
Loda
Daniela
D
Garrone
Annalisa
A
Benedetto
Alessandro
A
Mondo
Alessandra
A
Tisato
Ernesto
E
Zanoni
Mariagrazia
M
Zoppi
Simona
S
Dondo
Alessandro
A
Tagliabue
Silvia
S
Bonora
Stefano
S
Zanardi
Giorgio
G
Pacciarini
M Lodovica
ML
D000818:Animals; D015373:Bacterial Typing Techniques / Q000379:methods*; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology*; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000235:genetics*; D005838:Genotype; D007558:Italy; D018598:Minisatellite Repeats; D009161:Mycobacterium / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D009163:Mycobacterium bovis / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D011110:Polymorphism, Genetic; D014380:Tuberculosis, Bovine / Q000382:microbiology*
D004269:DNA, Bacterial