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Genotypic divergence of Avibacterium paragallinarum isolates with different growth requirements for nicotinamide adenine dinucleotide

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journal contribution
posted on 2019-11-27, 16:22 authored by Ok-Mi Jeong, Min-Su Kang, Patrick J. Blackall, Byung-Woo Jeon, Jin-Hyun Kim, Jiyeon Jeong, Hye-Jin Lee, Dong-Wan Kim, Yong-Kuk Kwon, Jae-Hong Kim

In 2017, for the first time in Asia, we reported the isolation of variants of Avibacterium paragallinarum with atypical NAD dependency. The present study was conducted to characterize the genotypes of 24 isolates of Av. paragallinarum in Korea, including the four variants reported previously. Most of the typical isolates (19/20) showed a unique ERIC-PCR pattern with no ERIC-PCR patterns in common between the typical isolates and the variants. Furthermore, the variants shared no ERIC-PCR patterns among themselves. All the typical NAD-dependent isolates belonged to the same phylogenetic group based on both 16S rRNA and hagA gene sequences. The four variants were placed in several groups distinct from the typical isolates. In the 16S rRNA phylogenetic analysis, two of the variants were not closely aligned to any other Av. paragallinarum, isolate although they were clearly members of the genus Avibacterium. The other variants were clustered together with NAD atypical isolates from geographically diverse global locations. Compared with the Modesto reference strain AY498870, all the variants lacked a TTTTT stretch at positions 182–186 in the 16S rRNA gene and the same deletion was shown in most of the reported variants. The typical isolates and variants shared 97.3–98.2% and 95.2–97.2% nucleotide sequence similarity, for 16S rRNA and hagA, respectively. In addition, the similarities among variants were within 98.3–100% and 96.5–98.4% for the two genes, respectively. Our results indicate that the Av. paragallinarum variants with altered NAD growth requirements were genetically different and highly divergent from the typical NAD-dependent isolates.

RESEARCH HIGHLIGHTS

NAD variant Korean Av. paragallinarum isolates show genetic diversity, whereas typical Korean Av. paragallinarum isolates do not.

The Korean variants were not closely aligned to all other Av. paragallinarum in the 16S rRNA phylogeny.

NAD atypical isolates from geographically diverse global locations clustered together.

Almost all variants, including all Korean variants of Av. paragallinarum, lack a specific fragment of the 16S rRNA gene.

NAD variant Korean Av. paragallinarum isolates show genetic diversity, whereas typical Korean Av. paragallinarum isolates do not.

The Korean variants were not closely aligned to all other Av. paragallinarum in the 16S rRNA phylogeny.

NAD atypical isolates from geographically diverse global locations clustered together.

Almost all variants, including all Korean variants of Av. paragallinarum, lack a specific fragment of the 16S rRNA gene.

Funding

This work was supported by the Animal and Plant Quarantine Agency (APQA) [grant number N-1543084-2018-19-01].

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