Emerging, non-PCV13 serotypes 11A and 35B of Streptococcus pneumoniae show high potential for biofilm formation in vitro

Background: Since the use of pneumococcal conjugate vaccines PCV7 and PCV13 in children became widespread, invasive pneumococcal disease (IPD) has dramatically decreased. Nevertheless, there has been a rise in incidence of Streptococcus pneumoniae non-vaccine serotypes (NVT) colonising the human nasopharynx. Nasopharyngeal colonisation, an essential step in the development of S. pneumoniae-induced IPD, is associated with biofilm formation. Although the capsule is the main pneumococcal virulence factor, the formation of pneumococcal biofilms might, in fact, be limited by the presence of capsular polysaccharide (CPS). Methodology/Principal Findings: We used clinical isolates of 16 emerging, non-PCV13 serotypes as well as isogenic transformants of the same serotypes. The biofilm formation capacity of isogenic transformants expressing CPSs from NVT was evaluated in vitro to ascertain whether this trait can be used to predict the emergence of NVT. Fourteen out of 16 NVT analysed were not good biofilm formers, presumably because of the presence of CPS. In contrast, serotypes 11A and 35B formed >45% of the biofilm produced by the non-encapsulated M11 strain. Conclusions/Significance This study suggest that emerging, NVT serotypes 11A and 35B deserve a close surveillance

Latvian neutral policy and neutrality 1933 - 1940

Darba mērķis ir raksturot Latvijas izvairīšanos politiku no lielvalstu konfliktiem laika posmā no 1933. līdz 1940. gadam, kura nosaukta par neitrālo politiku un neitralitāti. Teorētiski izvairīties no lielvalstu konfliktiem iespējams visdažādākos veidos – gan veidojot reģionālu mazo valstu savienību, gan mēģinot noslēgt alianses līgumu ar lielvalstīm utt. Tomēr vēsturiski mazajām valstīm tieši neitralitāte citu valstu konfliktos ir bijusi vispieņemtākā un labākā alternatīva galveno mērķu – suverenitātes un teritoriālās neaizskaramības sasniegšanā. Pētījuma uzdevumi paredz analizēt šīs stratēģijas galvenās problēmas, pamatot neitrālās un neitralitātes politikas jēdzienu lietošanu, nodefinēt to galvenos posmus.The aim of this work is to research Latvian neutrality and neutral policy between the European great powers from 1933 till 1940. Theoretically there are many tactics how a small state can stay away from conflicts of big nations. But historically only neutrality was the most successful and acceptable policy. There are impossible to speak about Latvian neutrality from 1933 till 1938, due to its commitment with the League of Nations, therefore we are using another term – neutral policy. After Latvian agreement with USSR at 4 October 1939 Latvian neutrality was undermined again, because of deployment of soviet troops on Latvian soil