Phenotypic and genotypic analysis of Salmonella enterica serovar Kottbus in Germany

Salmonella enterica serovar Kottbus ( S. Kottbus) is isolated in many geographically diverse regions and caused sporadic outbreaks. Contaminated bottled water, Alfalfa sprouts and human milk have been identified as source of infection of S. Kottbus for humans. However this serovar has been also isolated frequently from poultry and poultry meat, especially from turkey worldwide. We have investigated by comparative molecular typing 95 epidemiological unrelated S. Kottbus isolates from poultry/poultry meat, pig/pork, cattle, reptile, the environment and humans received at the NRL-Salm and the NRZ-RKI between 2000 and 2011 to identify potential sources of human infection caused by this serovar in Germany. MLST analysis detected three main phylogenetic lineages. Most human isolates belonged to sequence type ST212. Nevertheless human strains and strains isolated from poultry/poultry meat shared another sequence type ST582. Only seven strains (4 human, 1 pork and 2 reptiles) were associated with ST808 or ST1669. The lineages were generally confirmed by PFGE and DNA microarray analysis of 102 pathogenicity genes. Altogether 43% of the strains tested were multidrug-resistant while most of these strains were resistant against CIP and NAL. Overall this study showed that in Germany with sequence type ST582 of S. Kottbus contaminated poultry/poultry meat was identified as one substantial source of human infection and consequently presents a risk for human health.