[32]. Although no statistical correlation was performed, it was observed that isolates belonging to the capsular type II were confined to MT1, indicating that the genetic background of this serotype may be well conserved. Higher number of isolates may corroborate these PD-1/PD-L1 assay findings. All isolates were susceptible to the antimicrobials evaluated in this study, except erythromycin and clindamycin. Although it was not an epidemiological investigation, the overall rate of erythromycin resistance among the isolates analyzed was 19.3%. Previous epidemiological and bacterial collection data from Brazilian GBS isolates showed that erythromycin resistance ranged from 4 to 14% [10–13].

A higher incidence rate LY2835219 clinical trial was observed in other regions, where erythromycin resistance up to 40% among GBS isolates was detected in Europe [15] and USA [3, 9].

In this study, resistance to both erythromycin and clindamycin was observed in GBS isolates of capsular types III and V, whereas the isolates displaying resistance only to erythromycin were exclusively found in the Ia capsular type. Similar results were previously obtained by other authors [3, 10]; however, resistant isolates for both antimicrobials were also observed among the Ib, II, IV, VI and VIII capsular serotypes [3, 34]. The mechanisms of macrolide resistance are mediated by ermA, ermB and mefA/E, and the distribution of these genes among GBS isolates in this study were in accordance with the macrolide-resistance AZD8186 cost phenotypes. These results were also observed by others [10–13]. The increasing numbers of isolates showing macrolide resistance together with the description of reduced susceptibility to penicillin emphasize the need for continued monitoring of antimicrobial susceptibility profile to identify the emergence of resistance among GBS isolates. Data of the potential virulence of GBS isolates from Brazil are limited. Three genomic islands encoding the structurally distinct types of pili (PI-1, PI-2a and PI-2b) were identified in GBS. These pili are organized

in two different loci, where PI-2a and PI-2b PLEK2 are located at the same chromosomal locus, with these being mutually exclusive [35]. To our knowledge, this is the first study describing the prevalence of the pilus island in Brazilian GBS isolates, and at least one pilus type was detected among the isolates, supporting their use as an antigen for vaccine development. The combination of PI-1 and PI-2a was the most prevalent among the GBS isolates, and this result is in agreement with previous reports [21, 36]. In addition, the presence of this combination was correlated with maternal colonization and invasive disease in adults [36]. The cyl locus of GBS consists of a cluster of twelve genes [27], and some of them can modulate cylE expression and secretion [37], which is crucial for β-H/C activity.