Mirko Rossi's research group

In Finland, as in most countries, the true impact of foodborne and waterborne diseases (FWD) is unknown. To prioritize food safety and environmental health interventions aimed to reduce the burden of FWDs, it is necessary to improve our knowledge in the ecology of the FWD pathogens and to reveal the molecular mechanisms regulating pathogen evolution and its interaction with the hosts.

Therefore, our research is focused on the following topics.

Our research group has been a pioneer in assessing the ecology and epidemiology of campylobacter infections in Finland by applying modern molecular typing methods (PFGE, MLST, wgMLST). We have analyzed the subtypes circulating among chicken slaughter batches, waterborne sources and human patients and evaluated the associated zoonosis risk. Furthermore we have deciphered the genetic characteristics of a highly virulent lineage (ST-677 CC) by using comparative genomics. Our recent research activities have focused on the prevalence, diversity and antibiotic resistance of Campylobacter jejuni in wild and game birds in Finland, and the effect of raw feed on the prevalence of C. jejuni in dogs. Our latest research is focused on deciphering the campylobacter population in wild rodents in Finland.

DVM Mirko Rossi, docent, associate professor
PhD Rauni Kivistö, docent, university lecturer
PhD Ann-Katrin Llarena, postdoctoral researcher
MSc Sara Kovanen, postdoctoral researcher
DVM Marja-Liisa Hänninen, professor emerita


Glycans decorate nearly all proteins in the host body, respond rapidly and dramatically to inflammatory cues, and have been centrally implicated in regulating the immune response. In addition, glycans decorate the external surface of all bacteria and contribute substantially in the interaction with the host and predators, being therefore subjected to strong environmental selection. With the advent of new technologies, and a great interest in the intersection of glycobiology and immunology, significant advances in understanding how glycosylation may allow pathogens to subvert the immune system or to serve as targets for the immune system are currently being accomplished. We are focusing on elucidating molecular mechanisms behind the biosynthesis of glycan structures in Campylobacter coli and their role in host response during infections.

DVM Mirko Rossi, docent, associate professor
MSc Alexandra Culebro, PhD student

Assessing the genomic diversity in Campylobacter jejuni population is critical for deducing whether genomic differences between any two isolates are sufficiently small to assume a high likelihood of epidemiological relatedness. However, the evolutionary mechanisms and ecological conditions maintaining this diversity remain obscure. A key piece towards resolving this puzzle is the accurate assessment of mutation rates and the molecular spectrum of mutational events in C. jejuni. Yet, neither long-term evolutionary studies nor studies on the evolutionary change over time in a natural population setting are currently available for this important pathogen. Moreover, recombination plays a dominant role in the evolution of this bacterial pathogen, but its dynamics remain only partly understood. By applying high throughput sequencing technology to experimentally evolved C. jejuni strains, we aim to generate an unbiased direct estimate of the spectrum and rate of spontaneous mutations accumulated in a neutral environment, and to define evolution dynamics during adaptation. In addition we are investigating chromosomal integration patterns after natural transformation by combining NGS analysis and in vitro transformation system.

DVM Mirko Rossi, docent, associate professor
MSc student Xiaochang Yang