The Beijing isolate responsible for the TB outbreak on Gran Canaria

Island was not distinguishable Ilomastat in vitro from other isolates. It had an average intracellular growth rate and did not control TNF-α levels at early stages of the infection. When we considered the cluster/orphan status of the isolates, analysis of intracelullar growth rates and cytokine expression profiles did not reveal a correlation between cluster/orphan status and infective behaviour in the THP-1 model. Discussion The worldwide distribution of the Beijing lineage has been well documented [6–8], being this genotype highly prevalent (70-80% in total isolates) in East Asia (China, Korea, Japan, etc). However, the proportion of Beijing strains in Western Europe is low. In two countries of the Mediterranean area, Italy and Spain, the marked increase in the number of immigrants in recent years has led to an increase in the numbers of TB cases that can be attributed to imported strains. In Madrid (Spain) and Tuscany (Italy) BIIB057 order during the period 2004-2006, slightly more than 40% of all cases of TB were detected in immigrants [15, 21]. We characterized the genotypic and phenotypic features of the Beijing lineage in a setting where it is not frequently isolated and where it is mostly detected in immigrant cases. Spoligotyping, sequencing of pks15/1, and analysis of the presence of the RD105 region revealed a low representativeness

of this lineage in our population, as previously described in Central and Western Europe [8, 9, 22]. These studies also showed that Beijing strains in our area are mainly found in immigrants (ie, around 85% of our isolates were from immigrants, mostly Peruvians and Ecuadorians). This is consistent with the results of studies which report that the Beijing lineage was also imported to Europe via South America [23, 24]. The Farnesyltransferase Beijing lineage is generally considered

to be associated with drug-resistant phenotypes, although this may not be true for all geographic settings [7, 8] and most of the Beijing strains in our study were susceptible. In fact, drug-resistant but also pan-susceptible strains have been associated with TB outbreaks [25] and it has recently been proposed that mainly atypical variants of Beijing strains are those linked to resistance [26]. IS6110-RFLP based genotyping was performed in order to establish a molecular epidemiological profile for the Beijing strains in the Spanish sample. Nineteen representative patterns of the Beijing genotype have been reported, and most of them have a high IS6110 copy number (15-26) [6, 27]. The wider range of IS6110 copy numbers– 9 to 22–alerts to the existence of Beijing isolates without a high number of IS6110 copies. The RFLP patterns of a 5-year population based AZD5363 research buy sample enabled us to define two clusters including 7 of the 26 Beijing isolates of the study (26.