Metagenomic analysis of isolation methods of a targeted microbe, Campylobacter jejuni, from chicken feces with high microbial contamination

Junhyung Kim, Jae Ho Guk, Seung Hyun Mun, Jae Uk An, Hyokeun Song, Jinshil Kim, Sangryeol Ryu, Byeonghwa Jeon, Seongbeom Cho

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Background: Originating from poultry, particularly chickens, Campylobacter jejuni is the leading foodborne pathogen worldwide and a major cause of campylobacteriosis. Isolating C. jejuni is difficult due to its specific growth requirements, the presence of viable but non-culturable bacteria, and because it is often masked by competing flora. Currently, there is no optimized method for isolating C. jejuni from chicken feces. Here, we evaluated the method for isolating C. jejuni from chicken feces using culture-independent sequence-based metagenomics and culture-dependent tools. Further, we assessed changes in microbial communities during microbe isolation to determine how the process can be improved. Results: Fourteen different variations of C. jejuni isolation procedures were applied to all 35 chicken fecal samples. These variations included using different enrichment broths (without enrichment or enrichment in Bolton or Preston broth), different ratios of sample-to-enrichment broth (1:101, 1:102, and 1:103), and different selective agars (modified charcoal-cefoperazone-deoxycholate agar (mCCDA) or Preston agar). Enrichment during isolation of C. jejuni was evaluated on the basis of microbial diversity and taxonomic composition using metagenomics tools. The effect of selective media was evaluated using a combination of metagenomics and culture-dependent tools. Microbial diversity significantly decreased during the enrichment process, regardless of the type of enrichment broth, with the most significant decrease observed at a feces-to-broth ratio of 1:103. Particularly, in 103-Preston broth, the relative abundance of Campylobacter increased, while extended-spectrum beta-lactamase-producing Escherichia coli, which interfere with Campylobacter isolation, decreased. Metagenomics results were validated by quantitative PCR and culture-dependent analysis. Additionally, selective media affected the isolation results, although microbes with high relative abundance during enrichment were also frequently isolated using culture-dependent methods. Significantly more C. jejuni was isolated from mCCDA than from Preston agar enriched in 103 Preston broth. Conclusions: Enrichment in Preston broth at a ratio of 1:103 followed by spreading onto mCCDA was the most effective method for isolating C. jejuni. This is the first study to apply metagenomics to evaluate a method for isolating a targeted microbe, C. jejuni, from chicken feces, a source with high microbial contamination. Thus, metagenomics can be applied to improve methods for isolating bacteria that are difficult to separate.

Original languageEnglish (US)
Article number67
JournalMicrobiome
Volume7
Issue number1
DOIs
StatePublished - Apr 25 2019
Externally publishedYes

Bibliographical note

Funding Information:
This research was supported by a grant from National Research Foundation of Korea Grant funded by the Korean Government (NRF-2018R1A2B6002396) and a grant from the Ministry of Food and Drug Safety (16162MFDS029).

Publisher Copyright:
© 2019 The Author(s).

Keywords

  • Campylobacter jejuni
  • Isolation method
  • Metagenomics
  • Microbial community analysis

Fingerprint

Dive into the research topics of 'Metagenomic analysis of isolation methods of a targeted microbe, Campylobacter jejuni, from chicken feces with high microbial contamination'. Together they form a unique fingerprint.

Cite this