Publikationsdatenbank

Experimental airborne colonization of piglets with livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) (2020)

Art

Hochschulschrift

Autor

Rosen, Kerstin (WE 10)

Quelle

Berlin, 2020 — 100 Seiten

Verweise

URL (Volltext): https://refubium.fu-berlin.de/handle/fub188/28923

Kontakt

Institut für Tier- und Umwelthygiene

Robert-von-Ostertag-Str. 7-13
14169 Berlin
+49 30 838 51845
tierhygiene@vetmed.fu-berlin.de

Abstract / Zusammenfassung

The airborne transmission of LA-MRSA sequence type ST398, firstly detected in 2005, has received a lot of research attention since their occurrence has become a regularity on pig farms, the main reservoir. Controlling the transmission and spread of LA-MRSA is a major issue regarding “One Health” due to its ability to colonize not only the entire livestock, but also humans. An increasing prevalence in regions with high livestock density highlights this importance. Understanding the various mechanisms behind MRSA colonization of piglets is of utmost necessity in order to establish measures for the prevention of further spreading of LA-MRSA. In our study, we established a newly experimental airborne MRSA colonization model of piglets, which can be used for reliable and reproducible MRSA colonization of piglets under less artificial conditions than found in other MRSA colonization models of pigs. A transient MRSA colonization of the piglets was detected when exposing the animals to an airborne MRSA concentration of 104 cfu/m3 for 24 hours in the aerosol chamber. Exposure to an airborne MRSA concentration of 106 cfu/m3 resulted in persistently MRSA colonized piglets. In addition, we investigated possible predisposing factors for successful MRSA colonization. We explored the role of weaning stress in MRSA colonization by imitating the stressed immunological state using a dexamethasone treatment. In addition, we investigated the effect of presence of airborne bacterial endotoxins on the MRSA colonization status of pigs. Our results indicate that despite their systemic effects on the organism, these factors do not promote the MRSA colonization in piglets. The limited exposure time of the piglets in the aerosol chamber contradicts the time of airborne MRSA exposure during the complete fattening period in field conditions and must be mentioned as a limitation of the study. A variety of environment factors may interact with MRSA colonization in the field. This underlines the difficulties in imitating field conditions in experimental colonization models. Moreover, antibiotic treatment of the piglets with the frequently used antibiotic tiamulin did not promote MRSA colonization, additionally demonstrating the difficulties in imitating field conditions in an animal model. Further research is warranted for deeper insights into the possible mechanisms influencing the MRSA colonization of piglets. This knowledge is essential to limit the further spreading of LA-MRSA in the livestock and thus the transmission to humans.