@article{SoundararajanMarincolaLiongetal.2023,
  author    = {Soundararajan, Manonmani and Marincola, Gabriella and Liong, Olivia and Marciniak, Tessa and Wencker, Freya D. R. and Hofmann, Franka and Schollenbruch, Hannah and Kobusch, Iris and Linnemann, Sabrina and Wolf, Silver A. and Helal, Mustafa and Semmler, Torsten and Walther, Birgit and Schoen, Christoph and Nyasinga, Justin and Revathi, Gunturu and Boelhauve, Marc and Ziebuhr, Wilma},
  title     = {Farming practice influences antimicrobial resistance burden of non-aureus staphylococci in pig husbandries},
  series = {Microorganisms},
  volume    = {11},
  journal   = {Microorganisms},
  number    = {1},
  issn      = {2076-2607},
  doi       = {10.3390/microorganisms11010031},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-312750},
  year      = {2023},
  abstract  = {Non-aureus staphylococci (NAS) are ubiquitous bacteria in livestock-associated environments where they may act as reservoirs of antimicrobial resistance (AMR) genes for pathogens such as Staphylococcus aureus. Here, we tested whether housing conditions in pig farms could influence the overall AMR-NAS burden. Two hundred and forty porcine commensal and environmental NAS isolates from three different farm types (conventional, alternative, and organic) were tested for phenotypic antimicrobial susceptibility and subjected to whole genome sequencing. Genomic data were analysed regarding species identity and AMR gene carriage. Seventeen different NAS species were identified across all farm types. In contrast to conventional farms, no AMR genes were detectable towards methicillin, aminoglycosides, and phenicols in organic farms. Additionally, AMR genes to macrolides and tetracycline were rare among NAS in organic farms, while such genes were common in conventional husbandries. No differences in AMR detection existed between farm types regarding fosfomycin, lincosamides, fusidic acid, and heavy metal resistance gene presence. The combined data show that husbandry conditions influence the occurrence of resistant and multidrug-resistant bacteria in livestock, suggesting that changing husbandry practices may be an appropriate means of limiting the spread of AMR bacteria on farms.},
  language  = {en}
}
@article{KlotzHigginsSchaubmaretal.2019,
  author    = {Klotz, Peter and Higgins, Paul G. and Schaubmar, Andreas R. and Failing, Klaus and Leidner, Ursula and Seifert, Harald and Scheufen, Sandra and Semmler, Torsten and Ewers, Christa},
  title     = {Seasonal Occurrence and Carbapenem Susceptibility of Bovine Acinetobacter baumannii in Germany},
  series = {Frontiers in Microbiology},
  volume    = {10},
  journal   = {Frontiers in Microbiology},
  doi       = {10.3389/fmicb.2019.00272},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-325927},
  year      = {2019},
  abstract  = {Acinetobacter baumannii is one of the leading causes of nosocomial infections in humans. To investigate its prevalence, distribution of sequence types (STs), and antimicrobial resistance in cattle, we sampled 422 cattle, including 280 dairy cows, 59 beef cattle, and 83 calves over a 14-month period. Metadata, such as the previous use of antimicrobial agents and feeding, were collected to identify putative determining factors. Bacterial isolates were identified via MALDI-TOF/MS and PCR, antimicrobial susceptibility was evaluated via VITEK2 and antibiotic gradient tests, resistance genes were identified by PCR. Overall, 15.6\% of the cattle harbored A. baumannii, predominantly in the nose (60.3\% of the A. baumannii isolates). It was more frequent in dairy cows (21.1\%) than in beef cattle (6.8\%) and calves (2.4\%). A seasonal occurrence was shown with a peak between May and August. The rate of occurrence of A. baumannii was correlated with a history of use of 3rd generation cephalosporins in the last 6 months prior to sampling Multilocus sequence typing (Pasteur scheme) revealed 83 STs among 126 unique isolates. Nine of the bovine STs have previously been implicated in human infections. Besides known intrinsic resistance of the species, the isolates did not show additional resistance to the antimicrobial substances tested, including carbapenems. Our data suggest that cattle are not a reservoir for nosocomial A. baumannii but carry a highly diverse population of this species. Nevertheless, some STs seem to be able to colonize both cattle and humans.},
  language  = {en}
}
@article{TruebeHertleinMrochenetal.2019,
  author    = {Tr{\"u}be, Patricia and Hertlein, Tobias and Mrochen, Daniel M. and Schulz, Daniel and Jorde, Ilka and Krause, Bettina and Zeun, Julia and Fischer, Stefan and Wolf, Silver A. and Walther, Birgit and Semmler, Torsten and Br{\"o}ker, Barbara M. and Ulrich, Rainer G. and Ohlsen, Knut and Holtfreter, Silva},
  title     = {Bringing together what belongs together: Optimizing murine infection models by using mouse-adapted Staphylococcus aureus strains},
  series = {International Journal of Medical Microbiology},
  volume    = {309},
  journal   = {International Journal of Medical Microbiology},
  doi       = {10.1016/j.ijmm.2018.10.007},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-229081},
  pages     = {26-38},
  year      = {2019},
  abstract  = {Staphylococcus (S.) aureus is a leading cause of bacterial infection world-wide, and currently no vaccine is available for humans. Vaccine development relies heavily on clinically relevant infection models. However, the suitability of mice for S. aureus infection models has often been questioned, because experimental infection of mice with human-adapted S. aureus requires very high infection doses. Moreover, mice were not considered to be natural hosts of S. aureus. The latter has been disproven by our recent findings, showing that both laboratory mice, as well as wild small mammals including mice, voles, and shrews, are naturally colonized with S. aureus. Here, we investigated whether mouse-and vole-derived S. aureus strains show an enhanced virulence in mice as compared to the human-adapted strain Newman. Using a step-wise approach based on the bacterial genotype and in vitro assays for host adaptation, we selected the most promising candidates for murine infection models out of a total of 254 S. aureus isolates from laboratory mice as well as wild rodents and shrews. Four strains representing the clonal complexes (CC) 8, 49, and 88 (n = 2) were selected and compared to the human-adapted S. aureus strain Newman (CC8) in murine pneumonia and bacteremia models. Notably, a bank vole-derived CC49 strain, named DIP, was highly virulent in BALB/c mice in pneumonia and bacteremia models, whereas the other murine and vole strains showed virulence similar to or lower than that of Newman. At one tenth of the standard infection dose DIP induced disease severity, bacterial load and host cytokine and chemokine responses in the murine bacteremia model similar to that of Newman. In the pneumonia model, DIP was also more virulent than Newman but the effect was less pronounced. Whole genome sequencing data analysis identified a pore-forming toxin gene, lukF-PV(P83)/lukM, in DIP but not in the other tested S. aureus isolates. To conclude, the mouse-adapted S. aureus strain DIP allows a significant reduction of the inoculation dose in mice and is hence a promising tool to develop clinically more relevant infection models.},
  language  = {en}
}