Publikationsdatenbank

Identification of pathogens involved in umbilical infections in dairy calves and their susceptibility to antibiotics commonly used (2025)

Art

Vortrag

Autoren

Meier, Kim Kristin (WE 18)

Lübke-Becker, Antina (WE 7)

Merle, Roswitha (WE 16)

Müller, Kerstin Elisabeth (WE 18)

Schwarz, Stefan (WE 7)

Brombach, Julian (WE 7)

Feßler, Andrea T (WE 7)

Ahrens, Tanja (WE 7)

Stock, Annegret (WE 18)

Kongress

XXIV Middle European Buiatrics Congress

Kosice (Slowakei), 07. – 10.05.2025

Quelle

Abstracts from XXIV Middle European Buiatrics Congress

— S. 40–41

Sprache

Englisch

Kontakt

Nutztierklinik

Königsweg 65
14163 Berlin
+49 30 838 62261
klauentierklinik@vetmed.fu-berlin.de

Abstract / Zusammenfassung

Objective: Determination of pathogens involved in umbilical infections (UIs) in dairy calves and their susceptibility to antibiotics commonly used.
Material and methods: Between September 2022 and April 2024, five dairy farms in Brandenburg (Germany) were visited twice a week for twelve weeks. Interviews with farm or herd managers were conducted concerning the care of the neonate, and calves’ health, feeding, and housing. Each calf aged up to four weeks was clinically examined weekly including examination of the umbilicus for signs of inflammation (enlargement, heat, rough consistency, pain, discharge). Calves born during visits or calves with UIs accessible for sampling (e.g., discharge, fistula) were sampled using swabs. All samples were processed within 24 hours. Species identification of the cultivated bacteria was carried out using MALDI‑TOF. Susceptibility testing of relevant bacteria (Escherichia (E.) coli, Trueperella pyogenes, Staphylococcus aureus, Streptococcus uberis, Streptococcus dysgalactiae, Klebsiella spp.) to commonly used antibiotics was performed by broth microdilution to determine minimal inhibitory concentrations (MIC).
Results: Out of 1,248 calves clinically examined, 144 calves (11.5 %) had an UI, with little variation between farms (9.4 % to 14.2 %). Overall, 105 and 100 different bacterial species were isolated after birth and from calves with UIs, respectively. The bacteria most frequently isolated in 47 postnatal samples were E. coli, Mammaliicoccus sciuri and Aerococcus viridians. In contrast, in the 106 samples from UIs Trueperella pyogenes, Staphylococcus aureus, Streptococcus dysgalactiae and Streptococcus uberis were isolated in addition to E. coli and Mammaliicoccus sciuri. Anaerobic bacteria (e.g., Bacteroides spp., Clostridium perfringens) were almost exclusively found in UIs. More than two thirds of all Staphylococcus aureus isolates tested were methicillin‑resistant and, therefore, resistant to beta‑lactam‑antibiotics. The susceptibility to penicillin/ benzylpenicillin, mainly used in the treatment of UIs, was high for Streptococcus spp. [MIC90: ≤ 0.0625 μg/ml (Streptococcus dysgalactiae), 0.25 μg/ml (Streptococcus uberis)] and Trueperella pyogenes (MIC90: ≤ 0.015 μg/ml). The same was observed for amoxicillin/clavulanic acid and all pathogens investigated. All bacteria tested, however, showed low susceptibilities to tetracycline (MIC90: ≥ 16 μg/ml). Since E. coli isolates from calves with UIs from farms using chlortetracycline spray had significantly higher MICs for ampicillin, enrofloxacin, tetracycline, and trimethoprim/ sulfamethoxazole compared to farms using iodine for navel care, an association with the respective product used can be assumed. Comparing MICs for E. coli isolated from calves sampled after birth and calves with UIs, the latter showed lower susceptibilities to almost all antibiotics tested.
Conclusions: The diversity of bacterial species isolated from UIs highlights the complexity of their bacterial spectrum and the difficulty in distinguishing between microbiota, infecting, or contaminating bacteria. Besides considering the prudent and off‑label‑use of antibiotics, the overall low susceptibility to tetracycline shows the unsuitability of tetracycline for navel care, but rather a possible promotion of antimicrobial resistance. The high susceptibility of streptococci and T. pyogenes to first‑line antibiotics (penicillin, aminopenicillin) promises successful treatments if timely administered. The high percentage of E. coli isolates in both sampling groups indicates the need for further investigations to determine the role of different E. coli strains in UI.