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to sequence typing in Streptococcus pneumoniae causing invasive disease in Chinese children. Eur J Clin Microbiol Infect Dis 2011,31(3):217–223.PubMedCrossRef 39. Vestrheim DF, Hoiby EA, Aaberge IS, Caugant DA: Phenotypic and genotypic characterization of Streptococcus pneumoniae strains colonizing children attending day-care centers in Norway. J Clin Microbiol 2008,46(8):2508–2518.PubMedCrossRef 40. Shin J, Baek JY, Kim SH, Song JH, Ko KS: Predominance of ST320 among Streptococcus pneumoniae serotype 19A isolates from 10 Asian countries. J Antimicrob Chemother 2011,66(5):1001–1004.PubMedCrossRef 41. Ko KS, Song selleck chemicals JH: Evolution of erythromycin-resistant Streptococcus

pneumoniae from Asian countries that contains erm(B) and mef(A) genes. J Infect selleck chemicals llc Dis 2004,190(4):739–747.PubMedCrossRef 42. McGee L, McDougal L, Zhou J, Spratt BG, Tenover FC, George R, Hakenbeck R, Adriamycin datasheet Hryniewicz W, Lefévre JC, Tomasz A, et al.: Nomenclature of major antimicrobial-resistant clones of Streptococcus pneumoniae defined by the pneumococcal molecular epidemiology network. J Clin Microbiol 2001,39(7):2565–2571.PubMedCrossRef Authors’ contributions LZ and XM conducted the laboratory work, performed the analysis, wrote the draft, and are the co-first authors for the same contributions of this study. WG, KY, AS, and SY provided the bacterial isolates and laboratory supplies. YY planned the study. All

authors read and approved the final manuscript.”
“Background In the oral cavity, bacteria encounter many different stress factors. Shear-forces see more and high flow rates of saliva dominate on exposed surfaces, while bacteria colonizing the gingival crevices and/or subgingival pockets have to contend and withstand with the host’s immune response. As in most other environments, bacteria form biofilms as protection from these harsh conditions [1]. The bacterial community colonizing the oral cavity is highly complex and varies considerably between different individuals. According to current reports, 600 to 700 established species and likely several thousand only partially cultivable taxa can be detected [2]. However, this consortium does not pose a threat to a healthy individual. It even has a protective function by preventing the establishment or predominance of harmful organisms [3]. Several factors like imbalanced nutrition, smoking, diabetes, emotional stress, or genetic predisposition [4] can lead to changes in the composition of this subgingival community, leading to a loss of the natural ecological balance. Potentially pathogenic species may increase in numbers, starting to cause persistent infections of host tissues that are capable to cause not only tooth loss and bone resorption but also can spread out to extra-oral sites and become systemic [5].

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