Twenty-five different genotypes were identified from the selleck kinase inhibitor 26 isolates analyzed. Four of the five MIRU-15 clusters were sub-divided by MIRU-15+5 (Figure 1C), and only the C1 cluster defined by MIRU-15 remained intact. Infectivity characterization i) click here Intracellular growth in THP-1 cells Eight of the 26 Beijing isolates characterized in the Spanish sample (1-8) were selected to assure a suitable variability according to different features: nationality of the cases (6 nationalities), drug susceptibility (2 resistant and 6 susceptible), number of IS6110 copies (9-22) and phylogenetic group (groups 3 and 4) (Table 2). The strain responsible for the outbreak on Gran Canaria Island was also included

(isolate no. 1). To widen the geographic setting to the Mediterranean area and to increase both the number Akt inhibitor of Beijing representatives analyzed and the number of isolates involved in clusters, we included to the Spanish Beijing representatives, eight additional Beijing isolates (9-16) from Tuscany, Italy (Table 2). As controls, we included the virulent reference strain H37Rv and a non-Beijing representative orphan strain. Table 2 Beijing strains assayed in THP-1 cells Isolate code Year of isolation Strain No. Nationality Drug

susceptibilitya IS6110 copy no.b Clustered/Orphan (+/-)c RD Groupd 8687 2002 1 Spain S 16 + 3 5204 2005 2 China S 22 – 3 7992 2005 3 Ecuador S 20 – 3 8281 2004 4 next Armenia S 21 – 3 6955 2003 5 Moldavia S 16 – 3 6898 2005 6 Ecuador S 9 – 3 5261 2006 7 Peru INH-R 22 – 4 673

2006 8 Ecuador S 13 + 3 1819 2005 9* Brazil S NA NA 3 1884 2005 10* Peru S NA NA 3 1284 2004 11* Italy INH-R SM-R 17 + 3 1538 2004 12* Peru S 20 + 3 1409 2004 13* China S 18 + 3 1254 2003 14* China S 21 + 3 838 2002 15* China S 11 – 2 1149 2003 16* Chile S 9 + 2 a INH-R, isoniazid-resistant; SM-R, streptomycin-resistant; S, pan-susceptible. b Number of bands identified by RFLP. NA, not available. c + and – indicate clustered/orphan status of the strain. NA, not available. d Phylogenetic classification according to the presence or absence of the RD181, RD150, and RD142 genomic regions, according to Reed et al [18]. * Isolates from Tuscany. A wide range of intracellular growth rates was detected among the Beijing isolates assayed (Figure 2). Two isolates showed the highest intracellular growth rates, which differed significantly (P < 0.05) from the others. There were no significant differences in growth rate among the remaining isolates, including control strain H37Rv and the non-Beijing orphan strain. No correlation was found between the epidemiological status of the isolates (clustered/unclustered) and the intracellular growth rates. The isolate responsible for the outbreak on Gran Canaria Island was included, although it did not show increased intracellular replication. Figure 2 Intracellular growth rate in differentiated THP-1 cells.