Abstract

BackgroundEnterococcus cecorum (EC) infection currently is one of the most important bacterial diseases of modern broiler chickens but can also affect ducks or other avian species. However, little is known concerning pathogenesis of EC and most studies concentrate on examinations of EC strains from broilers only. The objective of this study was to compare pathogenic and commensal EC strains from different animal species concerning different phenotypic and genotypic traits.ResultsPathogenic and commensal EC strains were not clearly separated from each other in a phylogenetic tree based on partial sequences of the 16S-rRNA-gene and also based on the fatty acid profile determined with gas chromatography. C12:0, C14:0, C15:0, C16:0, C17:0, C18:0, C18:1 w7c, C18:1 w9c and C20:4 w6,9,12,15c were detected as the major fatty acids. None of the 21 pathogenic EC strains was able to utilize mannitol, while 9 of 29 commensal strains were mannitol positive. In a dendrogram based on MALDI-TOF MS data, pathogenic strains were not clearly separated from commensal isolates. However, significant differences concerning the prevalence of several mass peaks were confirmed between the two groups. Two different antisera were produced but none of the serotypes was predominantly found in the pathogenic or commensal EC isolates. Enterococcal virulence factors gelE, esp, asa1, ccf, hyl and efaAfs were only detected in single isolates via PCR. No virulence factor was found significantly more often in the pathogenic isolates. The chicken embryo lethality of the examined EC isolates varied from 0 up to 100%. The mean embryo lethality in the pathogenic EC isolates was 39.7%, which was significantly higher than the lethality of the commensal strains, which was 18.9%. Additionally, five of the commensal isolates showed small colony variant growth, which was never reported for EC before.ConclusionsPathogenic and commensal EC isolates from different animal species varied in chicken embryo lethality, in their ability to metabolize mannitol and probably showed divergent mass peak patterns with MALDI-TOF MS. These differences may be explained by a separate evolution of pathogenic EC isolates. Furthermore, different serotypes of EC were demonstrated for the first time.

Highlights

  • Enterococcus cecorum (EC) infection currently is one of the most important bacterial diseases of modern broiler chickens but can affect ducks or other avian species

  • MALDI-TOF MS analysis All isolates were confirmed as EC using MALDI-TOF mass spectrometry

  • Masses 3787, 3788, 3922, 4594, 6322, 6527, 7869, 7882 and 8246 were detected significantly (P ≤ 0.05; Fisher’s exact test) more often in pathogenic isolate, while masses 3105, 3908, Detection of the fatty acid composition by gas chromatography Dodecanoic acid (C12:0), tetradecanoic acid (C14:0), pentadecanoic acid (C15:0), hexadecanoic acid (C16:0), heptadecanoic acid (C17:0), octadecanoic acid (C18:0), (11Z)11-octadecenoic acid (C18:1 w7c), (9Z)-9-octadecenoic acid (C18:1 w9c), (5Z,8Z,11Z,14Z)-5,8,11,14-eicosatetraenoic acid (C20:4 w6,9,12,15c), summed feature 3 (C15:0 iso 2OH and C16:1 w7c) and summed feature 5 (C18:0 anteiso and C18:2 w6,9c) were detected as the major fatty acids in the EC strains using gas chromatography (Table 3). Most of these fatty acids were detected in all EC strains, only C12:0, C17:0, C18:1 w7c and C20:4 w6,9,12,15c were missing in single isolates

Read more

Summary

Introduction

Enterococcus cecorum (EC) infection currently is one of the most important bacterial diseases of modern broiler chickens but can affect ducks or other avian species. Little is known concerning pathogenesis of EC and most studies concentrate on examinations of EC strains from broilers only. The objective of this study was to compare pathogenic and commensal EC strains from different animal species concerning different phenotypic and genotypic traits. Affected birds exhibit spondylitis of the free thoracic vertebra and lesions in the femoral head that are consistent with the clinical diseases known as femoral head necrosis or bacterial chondritis and osteomyelitis. In this study virulence and different phenotypic and genotypic properties of pathogenic and commensal Enterococcus cecorum strains from different animal species were compared

Objectives
Methods
Results
Discussion
Conclusion
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call