Dr Krzysztof Trzciński, is a microbiologist and Principal Investigator at the University Medical Centre Utrecht (UMCU) in the Netherlands. Before taking up the position of Associate Professor at UMCU he worked as a Senior Scientist at Harvard T.H. Chan School of Public Health, Boston, Massachusetts. His main area of interest is Streptococcus pneumoniae, whether it be a respiratory pathogen, or human commensal. In his work, Dr Trzciński focuses on innate and acquired immune responses to natural colonization with S. pneumoniae, as well as mechanisms maintaining the diversity of pneumococcal capsular types (serotypes) circulating and causing disease in the human population. He is using both experimental and epidemiological approaches in his research. Currently, he is developing advanced methods for detection of pneumococcal colonization across all ages, and for studying multi-serotype carriage. With his work, Dr Trzciński aims to broaden our understanding of the interactions between S. pneumoniae and the host during colonization and infection and enhance the knowledge necessary to assess accurately the effects of preventative strategies targeting pneumococcal disease.