prof. dr. ir. Z. (Krzysztof) Hartlief

prof. dr. ir. Z. (Krzysztof) Hartlief

Associate Professor
prof. dr. ir. Z. (Krzysztof) Hartlief
  • Infectious Diseases Research 4

Research Programs

Infection & Immunity



Dr Krzysztof Trzciński, is a microbiologist and Principal Investigator in the Respiratory Infections Research Group at the University Medical Centre Utrecht (UMCU).

Before taking up the position of Associate Professor at the Department of Pedatric Immunology and Infectious Diseases at UMCU in 2009, he worked as a Senior Research Scientist at Harvard T.H. Chan School of Public Health, Boston, Massachusetts.

His main area of interest is Streptococcus pneumoniae (pneumococcus), whether it be a respiratory pathogen, or human commensal. Despite available vaccines targeting pneumococcal disease, S. pneumoniae remains one of the top causes of death due to bacterial respiratory infections.

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. With his work, he contributed to the discovery that naturally acquired mucosal immunity to pneumococcal colonization is largely antibody-independent (Trzciński et al. Infect.Immun. 2005), yet antigen-specific (Trzciński et al. Infect.Immun. 2008), while transcending serotypes (Malley et al. PNAS 2005). These findings opened new opportunities in developing vaccines (Li et al. PLoS Path. 2012). Also, utilizing pneumococcal strains that differ only by serotype (Trzciński et al. App.Env.Microbiol. 2003), he and his co-workers showed that simple characteristics of the capsular polysaccharide allow predictions of prevalence of a serotype in carriage (Weinberger et al. PLoS Path. 2009, Li et al. Infect.Immun. 2013, Trzciński et al. MBio 2015) and invasiveness in disease (Hyams et al. Infect.Immun. 2013), and that capsular characteristics could be linked to variations in S. pneumoniae resistance to certain immune responses: opsonin-independent killing of pneumococci by neutrophils (Weinberger et al. PLoS Path. 2009) and the deposition of complement and opsonophagocytosis (Melin et al. Infect. Immun. 2010a; Melin et al. Infect.Immun. 2010b, Hyams et al. Infect.Immun. 2013). He also contributed to better understanding the factors mediating interaction between pneumoocci and other pathogens colonizing the upper respiratory tract, Staphylococcus aureus in particular (Regev-Yochay et al. J.Bac. 2006, Selva et al. PNAS 2009).

Currently, he is developing enhanced methods for pneumococcal colonization detection, and for studying multi-serotype carriage (Trzciński et al. PLoS ONE, 2013, Wyllie et al. PLoS ONE 2014, Krone et al. PLoS ONE 2015, Trzciński et al. MBio 2015, Miellet et al. CID 2021, Miellet et al. Front.Microbiol. 2022). 

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.

Side Activities

MSD, Advisory Boards (from 2019 onwards), payments always to UMC Utrecht (>€2200,-)

Pfizer, speaker (2018), payment to UMC Utrecht (>€2200,-)

Pfizer, Advisory Board (2017), payment to UMC Utrecht (<€2200,-)

Fellowship and Awards


2000                 British Society for Antimicrobial Chemotherapy Research Fellowship

1999                 European Respiratory Society Research Fellowship

1998                 Royal Society/NATO Research Fellowship

1997                 Award of the European Congress of Clinical Microbiology and Infectious Diseases, Lausanne, Switzerland

1994                 European Society of Clinical Microbiology and Infectious Diseases Young Scientist Research Fellowship

Research Output (80)

Detection of Neisseria meningitidis in saliva and oropharyngeal samples from college students

Miellet Willem R., Mariman Rob, Pluister Gerlinde, de Jong Lieke J., Grift Ivo, Wijkstra Stijn, van Logchem Elske M., van Veldhuizen Janieke, Immink Marie Monique, Wijmenga-Monsuur Alienke J., Rots Nynke Y., Sanders Elisabeth A.M., Bosch Thijs, Trzciński Krzysztof 30 Nov 2021, In: Scientific Reports. 11 , p. 1-9

Influenza-like Illness Exacerbates Pneumococcal Carriage in Older Adults

Miellet Willem R., Van Veldhuizen Janieke, Nicolaie Mioara A., Mariman Rob, Bootsma Hester J., Bosch Thijs, Rots Nynke Y., Sanders Elisabeth A.M., Van Beek Josine, Trzciński Krzysztof 1 Nov 2021, In: Clinical Infectious Diseases. 73 , p. E2680-E2689

Examining the Distribution and Impact of Single-Nucleotide Polymorphisms in the Capsular Locus of Streptococcus pneumoniae Serotype 19A

Arends D. W., Miellet W. R., Langereis J. D., Ederveen T. H.A., van der Gaast–de Jongh C. E., van Scherpenzeel M., Knol M. J., van Sorge N. M., Lefeber D. J., Trzcinski K., Sanders E. A.M., Dorfmueller H. C., Bootsma H. J., de Jonge M. I. 15 Oct 2021, In: Infection and Immunity. 89 , p. 1-14

The epidemiologic and biologic basis for classifying older age as a high-risk, immunocompromising condition for pneumococcal vaccine policy

Grant Lindsay R., Slack Mary P.E., Yan Qi, Trzciński Krzysztof, Barratt Jane, Sobczyk Elizabeth, Appleby James, Cané Alejandro, Jodar Luis, Isturiz Raul E., Gessner Bradford D. Jun 2021, In: Expert Review of Vaccines. 20 , p. 691-705 15 p.

Upper respiratory tract colonization with Streptococcus pneumoniae in adults

Arguedas Adriano, Trzciński Krzysztof, O’Brien Katherine L., Ferreira Daniela M., Wyllie Anne L., Weinberger Daniel, Danon Leon, Pelton Stephen I., Azzari Chiara, Hammitt Laura L., Sá-Leão Raquel, Brandileone Maria Cristina C., Saha Samir, Suaya Jose, Isturiz Raul, Jodar Luis, Gessner Bradford D. 2 Apr 2020, In: Expert Review of Vaccines. 19 , p. 353-366 14 p.

Joint sequencing of human and pathogen genomes reveals the genetics of pneumococcal meningitis

Lees John A., Ferwerda Bart, Kremer Philip H.C., Wheeler Nicole E., Serón Mercedes Valls, Croucher Nicholas J., Gladstone Rebecca A., Bootsma Hester J., Rots Nynke Y., Wijmega-Monsuur Alienke J., Sanders Elisabeth A.M., Trzciński Krzysztof, Wyllie Anne L., Zwinderman Aeilko H., van den Berg Leonard H., van Rheenen Wouter, Veldink Jan H., Harboe Zitta B., Lundbo Lene F., de Groot Lisette C.P.G.M., van Schoor Natasja M., van der Velde Nathalie, Ängquist Lars H., Sørensen Thorkild I.A., Nohr Ellen A., Mentzer Alexander J., Mills Tara C., Knight Julian C., du Plessis Mignon, Nzenze Susan, Weiser Jeffrey N., Parkhill Julian, Madhi Shabir, Benfield Thomas, von Gottberg Anne, van der Ende Arie, Brouwer Matthijs C., Barrett Jeffrey C., Bentley Stephen D., van de Beek Diederik 15 May 2019, In: Nature Communications. 10

Visie op toekomstige surveillance van respiratoire bacteriële pathogenen

Mariman Rob, Bosch Thijs, Miellet Willem, Pluister Gerlinde N., van Veldhuizen Janieke, Sanders Elisabeth , Trzcinski Krzysztof 2019, In: Nederlands tijdschrift voor medische microbiologie. 27 , p. 217-220

The relative invasive disease potential of Streptococcus pneumoniae among children after PCV introduction:A systematic review and meta-analysis

Balsells Evelyn, Dagan Ron, Yildirim Inci, Gounder Prabhu P., Steens Anneke, Muñoz-Almagro Carmen, Mameli Chiara, Kandasamy Rama, Givon Lavi Noga, Daprai Laura, van der Ende Arie, Trzciński Krzysztof, Nzenze Susan A., Meiring Susan, Foster Dona, Bulkow Lisa R., Rudolph Karen, Valero-Rello Ana, Ducker Struan, Vestrheim Didrik Frimann, von Gottberg Anne, Pelton Stephen I., Zuccotti Gian Vincenzo, Pollard Andrew J., Sanders Elisabeth A.M., Campbell Harry, Madhi Shabir A., Nair Harish, Kyaw Moe H. 1 Nov 2018, In: Journal of Infection. 77 , p. 368-378 11 p.

Distribution of serotypes and patterns of antimicrobial resistance among commensal Streptococcus pneumoniae in nine European countries

Yahiaoui Rachid Y., Bootsma Hester J., den Heijer Casper D.J., Pluister Gerlinde N., John Paget W., Spreeuwenberg Peter, Trzcinski Krzysztof, Stobberingh Ellen E. 29 Aug 2018, In: BMC Infectious Diseases. 18

Sequencing of the variable region of rpsB to discriminate between Streptococcus pneumoniae and other streptococcal species

Wyllie Anne L, Pannekoek Yvonne, Bovenkerk Sandra, van Engelsdorp Gastelaars Jody, Ferwerda Bart, van de Beek Diederik, Sanders Elisabeth A M, Trzciński Krzysztof, van der Ende Arie Sep 2017, In: Open Biology. 7

All research output

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