# Multilocus Sequencing ofCorynebacterium pseudotuberculosis Biotype Ovis Strains

Authors: Boglárka Sellyei; Krisztián Bányai; Dániel Bartha; István Hajtós; László Fodor; László Makrai
Journal: BioMed Research International
 (2017)

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## Abstract

ThirteenCorynebacterium pseudotuberculosis biotype ovis strains isolated from clinical cases of caseous lymphadenitis in Hungary were characterised using multilocus sequencing and their phylogenetic comparison was carried out on the basis of four housekeeping genes (groEL1, infB,dnaK, andleuA). The in silico analysis of the 16 frequently studied housekeeping genes showed thatC. pseudotuberculosis strains could be readily distinguished fromC. diphtheriae andC. ulcerans strains; however, sequences of the same genes in the two biotypes of theC. pseudotuberculosis were highly similar; the heterogeneity values were low. GenesdnaK, infB,groEL1, andleuA showed marked genetic variation withinC. pseudotuberculosis, and strains of the two biotypes of C. pseudotuberculosis could be differentiated. Analysis of the individual genes showed a fairly conservative nature ofC. pseudotuberculosis biotype ovis strains. The greatest genetic differentiation was seen in thednaK andinfB genes and concatenations of these two genes were very useful in the genetic separation of the studied strains.


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## Body

## 1. Introduction

Corynebacterium pseudotuberculosiswas isolated from a sheep and described by Preisz [1] as a Gram-positive, facultative intracellular pathogen. Two major biotypes can be distinguished based on the ability of reduction of nitrate; the nitrate negative biotype (C. pseudotuberculosis biotype ovis) causes caseous lymphadenitis (CLA) in small ruminants [2–4], whereas the nitrate positive biotype (C. pseudotuberculosis biotype equi) is the causative agent of ulcerative lymphangitis in horses, cows, camels, buffaloes, and occasionally humans [5, 6]. CLA is a chronic, contagious disease that is characterised by abscess formation in or near major peripheral lymph nodes (external form) or within the internal organs and lymph nodes (internal form). CLA occurs worldwide; however, it is more frequent in the tropical areas and causes important economic losses in ovine and caprine herds by reducing wool, meat, and milk production [4, 7–10].Classification ofC. pseudotuberculosis was originally based on cultural, morphological, and biochemical characteristics [11]. In addition to nitrate reduction various molecular methods, restriction fragment length polymorphism (RFLP) of chromosomal DNA, ribotyping, and whole genome sequence analysis were used for the differentiation ofC. pseudotuberculosis biotypes [12–14].C. pseudotuberculosis biotype equi strains showed greater genetic divergence thanC. pseudotuberculosis biotype ovis strains when examined with pulsed field gel electrophoresis (PFGE), BOX-PCR, random amplified polymorphic DNA (RAPD), and amplification of DNA surrounding rare restriction sites (ADSRRS) [3, 15, 16].Multilocus sequence typing has become popular in bacterial genotyping technique over the past decade, including genotypingCorynebacterium spp.; it allows the identification of potential molecular genetic marker(s) in conservative genes for the differentiation of closely related bacterial strains [17, 18].The objective of this study was characterisation of Hungarian field strains ofC. pseudotuberculosis biotype ovis using multilocus sequencing and their phylogenetic comparison on the basis of selected housekeeping genes.


## 2. Materials and Methods

### 2.1. Bacterial Strains and Culture Condition

ThirteenC. pseudotuberculosis biotype ovis field strains isolated between 1994 and 2014 were randomly selected from the strain collection of the Department of Microbiology and Infectious Diseases, Faculty of Veterinary Science, Szent István University, Budapest, Hungary. After identification using standard methods [20], they had been stored at −80°C till the examinations. Details about the strains used in this study are described in Table 1.Table 1
The list and registered data ofC. pseudotuberculosis strains included in the examinations.
ID
Host
Place of isolation
Strains
Year
C1
Goat
Szentistván
C. pseudotuberculosis biotype ovis
1994
C3
Sheep
Vizsoly
C. pseudotuberculosis biotype ovis
2003
C7
Goat
Vizsoly
C. pseudotuberculosis biotype ovis
2003
C11
Sheep
Boldogkőváralja
C. pseudotuberculosis biotype ovis
2005
C12
Goat
Érd
C. pseudotuberculosis biotype ovis
2005
C14
Goat
Alsózsolca
C. pseudotuberculosis biotype ovis
2006
C15
Goat
Rudabánya
C. pseudotuberculosis biotype ovis
2006
C19
Goat
(DSM-7180)
C. pseudotuberculosis biotype ovis
1988
C21
Horse
(DSM-7177)
C. pseudotuberculosis biotype equi
1988
C22
Sheep
Mezőcsát
C. pseudotuberculosis biotype ovis
2013
C23
Goat
Csetény
C. pseudotuberculosis biotype ovis
2013
C24
Sheep
Pétervására
C. pseudotuberculosis biotype ovis
2009
C25
Goat
Szendrő
C. pseudotuberculosis biotype ovis
2011
C26
Goat
Csongrád
C. pseudotuberculosis biotype ovis
2014
C27
Goat
Kisvásárhely
C. pseudotuberculosis biotype ovis
2014Reference strains ofC. pseudotuberculosis biotype ovis (DSM-7180) andC. pseudotuberculosis biotype equi (DSM-7177) from the Leibniz Institute, German Collection of Microorganisms, and Cell Cultures (Braunschweig, Germany) were also included in the examinations.The strains were cultured on Columbia blood agar (LabM, Lancashire, UK) with the addition of 5% (vol/vol) sterile defibrinated sheep blood and incubated at 37°C for 48 h.


### 2.2. In Silico Sequence Analysis and Primer Design

In order to distinguishC. pseudotuberculosis biotypes from the closely related species and to find potential markers, the nucleotide sequences of 16 housekeeping genes of 15C. pseudotuberculosis, 13C. diphtheriae strains, and oneC. ulcerans strain (Table 2) were compared. The nucleotide sequences of 7 genes including the ATP synthase alpha chain (atpA), the DNA polymerase III alpha subunit (dnaE), the chaperone Hsp70 (dnaK), the elongation factor G (fusA), the 2-isopropylmalate synthase (leuA), the 2-oxoglutarate dehydrogenase E1 and E2 components (odhI), and the DNA-directed RNA polymerase beta chain (rpoB) were taken from [22, 23], while sequences of 9 genes involving ATP synthase beta chain (atpD), the heat shock proteins GroEL and GroES (groES,groEL1, andgroEL2), the translation initiation factor IF2 (infB), the DNA recombinational repair system (recA,recN), the alpha subunit of DNA dependent RNA polymerase (rpoA), and the manganese-dependent superoxide dismutase (sodA) were downloaded from the NCBI database (http://www.ncbi.nlm.nih.gov/genbank/).In silico analysis of the selected genes was performed with the ClustalW multiple alignment algorithm [24] in MegAlign software of the Lasergene 7 program suite (DNAStar, Madison, WI, USA) to find potentially useful markers for genetic differentiation and molecular epidemiological investigations.Table 2
The source ofCorynebacterium sp. examined in the in silico sequence analysis.
C. pseudotuberculosis
&
Biotype
Host
Origin
C. diphtheriae
§
Host
Origin
FRC41
Ovis
Human
France
NCTC 13129
Human
UK
3/99-5
Ovis
Sheep
Scotland
BH8
Human
Rio de Janeiro
P54B96
Ovis
Antelope
South Africa
C7
Human
Atlanta, GA, USA
1002
Ovis
Goat
Brazil
241
Human
Rio de Janeiro
C231
Ovis
Sheep
Australia
HC01
Human
Rio de Janeiro
I19
Ovis
Cow
Israel
VA01
Human
Rio de Janeiro
PAT10
Ovis
Sheep
Argentina
CDCE 8392
Human
Bethesda, MD, USA
42/02-A
Ovis
Sheep
Australia
31A
Human
Rio de Janeiro
267
Ovis
Llama
USA
HC03
Human
Rio de Janeiro
316
Equi
Horse
USA
HC02
Human
Rio de Janeiro
CIP 52.97
Equi
Horse
Kenya
INCA 402
Human
Rio de Janeiro
1/06-A
Equi
Horse
USA
PW8
Human
New York
31
Equi
Buffalo
Egypt
HC04
Human
Rio de Janeiro
258
Equi
Horse
Belgium
C. ulcerans
#
Cp162
Equi
Camel
UK
BR-AD22
Dog
Rio de Janeiro
&[14]; §[19]; #[21].Four genes (groEL1, infB,dnaK, andleuA) were selected for primer design; they are located at different genomic regions of bacteria (Figure 1). Primer sets were designed to amplify 580 bp, 654 bp, 641 bp, and 647 bp long fragments from the respective genomic regions; pending on the genes, the number of SNPs varied from 7 to 31 within the amplified fragments (Table 3). PCR primers were designed using Oligo Primer Analysis software 7 [25].Table 3
Primer sequences used for amplification and sequence analysis.
Locus
Putative gene product
Primer name
Sequence
Product size (bp)
Position on NC_014329.1 (FRC41 strain)
dnaK
Chaperone Hsp70
Cps dnaK F
5′-TCCTTACCAGTGCCCTTATCC-3′
580
2081944–2081964
Cps dnaK R
5′-GAGTTCCAGCGCATCACC-3′
2082507–2082524
groEL1
Heat shock protein
Cps groEL1 F
5′-ACCTTCACCGGATCATTG-3′
654
1978987–1979004
Cps groEL1 R
5′-TTGGTGATCGTCGTAAAGC-3′
1979623–1979641
i
n
fB
Translation initiation factor IF2
Cps infB F
5′-ATTGCGGGACTTGGACG-3′
641
1397768–1397784
Cps infB R
5′-GCATTATGCTGCACAAGACG-3′
1398390–1398409
leuA
2-isopropylmalate synthase
Cps leuA F
5′-AGCTCAGTGCGCGGTTGACC-3′
647
161252–161271
Cps leuA R
5′-ATGGCGTCGCGGGTTCG-3′
161915–161899Figure 1
The location ofin silico studied 16 housekeeping genes at the complete genome map ofC. pseudotuberculosis FRC41 [19]. The partial regions of rimmed four genes in frames were amplified and sequenced in this study.


### 2.3. PCR and Sequencing

A loopful of 48 h culture ofC. pseudotuberculosis was suspended in 6% Chelex-solution (Bio-Rad Laboratories, Hercules, CA, USA) and then heated to 65°C for 30 min and to 100°C for 8 min; afterwards, it was centrifuged. The supernatant was collected in a new tube and stored at −20°C until use. Fragments of the selected housekeeping genes were amplified by PCR in an Applied Biosystems 2720 Thermal Cycler (Thermo Fisher Scientific, Carlsbad, CA, USA). The 25 μl amplification reaction mixture contained 1x Dream Taq Buffer, 200 nM dNTP-mix, 1 μM of each primer, 1 U Dream Taq (Thermo Fisher Scientific, Carlsbad, CA, USA), template DNA, and water. The PCR program included 3 min of initial denaturation at 95°C and then 30 cycles at 95°C for 30 s, at 60°C for 30, and at 72°C for 30 s and 7 min of the final elongation. PCR products were purified for direct sequencing using the Geneaid PCR purification Kit (Geneaid Biotech, New Taipei, Taiwan). Templates were sequenced with the PCR primers using the BigDye Terminator Ready Reaction Mix v3.1. Nucleotide sequences were run on an ABI Prism 3100 Genetic Analyzer (Applied Biosystems, Foster City, CA).


### 2.4. Phylogenetic Analysis

Fragments of four protein-coding highly diverse housekeeping genes (groEL1, infB,dnaK, andleuA) were sequenced for all strains.Sequences were aligned using the ClustalW algorithm in the MEGA 6 software [26] and trimmed manually at the same position before being used for comparison with sequences of otherC. pseudotuberculosisstrains deposited in the GenBank. The same gene set fromC. diphtheriae HC02 was used as an outgroup.After the single gene alignments, the sequences were joined to make a concatemer of loci at head-to-tail in-frame. The phylogenetic trees were constructed by using the neighbour joining (NJ) method. The bootstrap technique [27] was employed to evaluate the reliability of tree topologies by resampling the sequence alignment 1000 times.


### 2.5. Nucleotide Sequence Accession Numbers

The determined partial gene sequences were deposited in GenBank under accession numbers: from MF491615 to MF491629 (dnaK); from MF464070 to MF464084 (infB); MF476990 and from MF476992 to MF477005 (groEL1); MF446654 and from MF446656 to MF446669 (leuA).


## 2.1. Bacterial Strains and Culture Condition

ThirteenC. pseudotuberculosis biotype ovis field strains isolated between 1994 and 2014 were randomly selected from the strain collection of the Department of Microbiology and Infectious Diseases, Faculty of Veterinary Science, Szent István University, Budapest, Hungary. After identification using standard methods [20], they had been stored at −80°C till the examinations. Details about the strains used in this study are described in Table 1.Table 1
The list and registered data ofC. pseudotuberculosis strains included in the examinations.
ID
Host
Place of isolation
Strains
Year
C1
Goat
Szentistván
C. pseudotuberculosis biotype ovis
1994
C3
Sheep
Vizsoly
C. pseudotuberculosis biotype ovis
2003
C7
Goat
Vizsoly
C. pseudotuberculosis biotype ovis
2003
C11
Sheep
Boldogkőváralja
C. pseudotuberculosis biotype ovis
2005
C12
Goat
Érd
C. pseudotuberculosis biotype ovis
2005
C14
Goat
Alsózsolca
C. pseudotuberculosis biotype ovis
2006
C15
Goat
Rudabánya
C. pseudotuberculosis biotype ovis
2006
C19
Goat
(DSM-7180)
C. pseudotuberculosis biotype ovis
1988
C21
Horse
(DSM-7177)
C. pseudotuberculosis biotype equi
1988
C22
Sheep
Mezőcsát
C. pseudotuberculosis biotype ovis
2013
C23
Goat
Csetény
C. pseudotuberculosis biotype ovis
2013
C24
Sheep
Pétervására
C. pseudotuberculosis biotype ovis
2009
C25
Goat
Szendrő
C. pseudotuberculosis biotype ovis
2011
C26
Goat
Csongrád
C. pseudotuberculosis biotype ovis
2014
C27
Goat
Kisvásárhely
C. pseudotuberculosis biotype ovis
2014Reference strains ofC. pseudotuberculosis biotype ovis (DSM-7180) andC. pseudotuberculosis biotype equi (DSM-7177) from the Leibniz Institute, German Collection of Microorganisms, and Cell Cultures (Braunschweig, Germany) were also included in the examinations.The strains were cultured on Columbia blood agar (LabM, Lancashire, UK) with the addition of 5% (vol/vol) sterile defibrinated sheep blood and incubated at 37°C for 48 h.


## 2.2. In Silico Sequence Analysis and Primer Design

In order to distinguishC. pseudotuberculosis biotypes from the closely related species and to find potential markers, the nucleotide sequences of 16 housekeeping genes of 15C. pseudotuberculosis, 13C. diphtheriae strains, and oneC. ulcerans strain (Table 2) were compared. The nucleotide sequences of 7 genes including the ATP synthase alpha chain (atpA), the DNA polymerase III alpha subunit (dnaE), the chaperone Hsp70 (dnaK), the elongation factor G (fusA), the 2-isopropylmalate synthase (leuA), the 2-oxoglutarate dehydrogenase E1 and E2 components (odhI), and the DNA-directed RNA polymerase beta chain (rpoB) were taken from [22, 23], while sequences of 9 genes involving ATP synthase beta chain (atpD), the heat shock proteins GroEL and GroES (groES,groEL1, andgroEL2), the translation initiation factor IF2 (infB), the DNA recombinational repair system (recA,recN), the alpha subunit of DNA dependent RNA polymerase (rpoA), and the manganese-dependent superoxide dismutase (sodA) were downloaded from the NCBI database (http://www.ncbi.nlm.nih.gov/genbank/).In silico analysis of the selected genes was performed with the ClustalW multiple alignment algorithm [24] in MegAlign software of the Lasergene 7 program suite (DNAStar, Madison, WI, USA) to find potentially useful markers for genetic differentiation and molecular epidemiological investigations.Table 2
The source ofCorynebacterium sp. examined in the in silico sequence analysis.
C. pseudotuberculosis
&
Biotype
Host
Origin
C. diphtheriae
§
Host
Origin
FRC41
Ovis
Human
France
NCTC 13129
Human
UK
3/99-5
Ovis
Sheep
Scotland
BH8
Human
Rio de Janeiro
P54B96
Ovis
Antelope
South Africa
C7
Human
Atlanta, GA, USA
1002
Ovis
Goat
Brazil
241
Human
Rio de Janeiro
C231
Ovis
Sheep
Australia
HC01
Human
Rio de Janeiro
I19
Ovis
Cow
Israel
VA01
Human
Rio de Janeiro
PAT10
Ovis
Sheep
Argentina
CDCE 8392
Human
Bethesda, MD, USA
42/02-A
Ovis
Sheep
Australia
31A
Human
Rio de Janeiro
267
Ovis
Llama
USA
HC03
Human
Rio de Janeiro
316
Equi
Horse
USA
HC02
Human
Rio de Janeiro
CIP 52.97
Equi
Horse
Kenya
INCA 402
Human
Rio de Janeiro
1/06-A
Equi
Horse
USA
PW8
Human
New York
31
Equi
Buffalo
Egypt
HC04
Human
Rio de Janeiro
258
Equi
Horse
Belgium
C. ulcerans
#
Cp162
Equi
Camel
UK
BR-AD22
Dog
Rio de Janeiro
&[14]; §[19]; #[21].Four genes (groEL1, infB,dnaK, andleuA) were selected for primer design; they are located at different genomic regions of bacteria (Figure 1). Primer sets were designed to amplify 580 bp, 654 bp, 641 bp, and 647 bp long fragments from the respective genomic regions; pending on the genes, the number of SNPs varied from 7 to 31 within the amplified fragments (Table 3). PCR primers were designed using Oligo Primer Analysis software 7 [25].Table 3
Primer sequences used for amplification and sequence analysis.
Locus
Putative gene product
Primer name
Sequence
Product size (bp)
Position on NC_014329.1 (FRC41 strain)
dnaK
Chaperone Hsp70
Cps dnaK F
5′-TCCTTACCAGTGCCCTTATCC-3′
580
2081944–2081964
Cps dnaK R
5′-GAGTTCCAGCGCATCACC-3′
2082507–2082524
groEL1
Heat shock protein
Cps groEL1 F
5′-ACCTTCACCGGATCATTG-3′
654
1978987–1979004
Cps groEL1 R
5′-TTGGTGATCGTCGTAAAGC-3′
1979623–1979641
i
n
fB
Translation initiation factor IF2
Cps infB F
5′-ATTGCGGGACTTGGACG-3′
641
1397768–1397784
Cps infB R
5′-GCATTATGCTGCACAAGACG-3′
1398390–1398409
leuA
2-isopropylmalate synthase
Cps leuA F
5′-AGCTCAGTGCGCGGTTGACC-3′
647
161252–161271
Cps leuA R
5′-ATGGCGTCGCGGGTTCG-3′
161915–161899Figure 1
The location ofin silico studied 16 housekeeping genes at the complete genome map ofC. pseudotuberculosis FRC41 [19]. The partial regions of rimmed four genes in frames were amplified and sequenced in this study.


## 2.3. PCR and Sequencing

A loopful of 48 h culture ofC. pseudotuberculosis was suspended in 6% Chelex-solution (Bio-Rad Laboratories, Hercules, CA, USA) and then heated to 65°C for 30 min and to 100°C for 8 min; afterwards, it was centrifuged. The supernatant was collected in a new tube and stored at −20°C until use. Fragments of the selected housekeeping genes were amplified by PCR in an Applied Biosystems 2720 Thermal Cycler (Thermo Fisher Scientific, Carlsbad, CA, USA). The 25 μl amplification reaction mixture contained 1x Dream Taq Buffer, 200 nM dNTP-mix, 1 μM of each primer, 1 U Dream Taq (Thermo Fisher Scientific, Carlsbad, CA, USA), template DNA, and water. The PCR program included 3 min of initial denaturation at 95°C and then 30 cycles at 95°C for 30 s, at 60°C for 30, and at 72°C for 30 s and 7 min of the final elongation. PCR products were purified for direct sequencing using the Geneaid PCR purification Kit (Geneaid Biotech, New Taipei, Taiwan). Templates were sequenced with the PCR primers using the BigDye Terminator Ready Reaction Mix v3.1. Nucleotide sequences were run on an ABI Prism 3100 Genetic Analyzer (Applied Biosystems, Foster City, CA).


## 2.4. Phylogenetic Analysis

Fragments of four protein-coding highly diverse housekeeping genes (groEL1, infB,dnaK, andleuA) were sequenced for all strains.Sequences were aligned using the ClustalW algorithm in the MEGA 6 software [26] and trimmed manually at the same position before being used for comparison with sequences of otherC. pseudotuberculosisstrains deposited in the GenBank. The same gene set fromC. diphtheriae HC02 was used as an outgroup.After the single gene alignments, the sequences were joined to make a concatemer of loci at head-to-tail in-frame. The phylogenetic trees were constructed by using the neighbour joining (NJ) method. The bootstrap technique [27] was employed to evaluate the reliability of tree topologies by resampling the sequence alignment 1000 times.


## 2.5. Nucleotide Sequence Accession Numbers

The determined partial gene sequences were deposited in GenBank under accession numbers: from MF491615 to MF491629 (dnaK); from MF464070 to MF464084 (infB); MF476990 and from MF476992 to MF477005 (groEL1); MF446654 and from MF446656 to MF446669 (leuA).


## 3. Results

As the use of MLST protocol ofCorynebacterium diphtheriae (https://pubmlst.org/cdiphtheriae/) proved to be inadequate for analysis ofC. pseudotuberculosis strains, developing of new scheme has been required.Thein silico analysis of the 16 frequently studied housekeeping genes showed thatC. pseudotuberculosis strains could be readily distinguished by sequence analysis fromC. diphtheriae andC. ulcerans strains; however, sequences of the same genes of theC. pseudotuberculosis strains belonging to the two biotypes were highly similar, and the heterogeneity values were low (Table 4). GenesdnaK, infB,groEL1, andleuA showed marked genetic variation withinC. pseudotuberculosis biotypes and they were selected for further genetic differentiation and molecular epidemiological investigations. The sequence diversity in these regions exceeded 5%.Table 4
Nucleic acid average sequence divergence of housekeeping genes inCorynebacterium species in the in silico study.
Gene
Full length(bp)
Average sequence divergence
C. diphtheriae versusC. pseudotuberculosis
C. ulcerans versusC. pseudotuberculosis
C. pseudotuberculosis biotype ovis versus equi
groEL1
1641
62.9
27.9
1.1
i
n
fB
2886
13.6
6.0
0.8
dnaK
1836
9.1
5.0
0.6
leuA
1818
14.0
8.1
0.5
odhI
3687
12.5
49.7
0.4
atpD
1446
6.2
3.2
0.4
recN
1740
27.0
10.6
0.4
dnaE
3561
58.2
7.1
0.3
groEL2
1641
59.5
27.6
0.3
recA
1110
14.1
7.3
0.3
rpoA
1017
7.7
3.5
0.3
fusA
2127
3.9
2.6
0.2
groES
297
6.5
3.5
0.2
rpoB
2974
8.0
3.3
0.2
sodA
600
10.0
4.3
0.2
atpA
1630
8.4
2.1
0.0C. pseudotuberculosis biotype ovis andC. pseudotuberculosis biotype equi field strains were differentiated with sequence analysis of the target gene fragments. Analysis of the individual genes showed a fairly conservative nature ofC. pseudotuberculosis biotype ovis strains, although segregation of some Hungarian strains (e.g., C1 and C19, C3, C23, and C27) together with strains from Australia, Israel, USA, South Africa, Scotland, France, and Brazil was also evident but they were clearly located in the cluster ofC. pseudotuberculosis biotype ovis. The greatest genetic differentiation was seen in thednaK andinfB genes and concatenations of these two genes were very useful in the genetic separation of the studied strains (Figure 2).Figure 2
Phylogenetic reconstruction based on the concatenated partial sequence ofdnaK (520 bp), infB (577 bp),groEL1 (588 bp), andleuA (597 bp) genes from the Hungarian field isolates and DSM type strains. Analysis was conducted using the neighbour joining (NJ) method. The 1000 bootstrap (BT) values are indicated at branching points. Bar % estimated nucleotide substitutions.


## 4. Discussion

C. pseudotuberculosis biotype ovis is the causative agent of caseous lymphadenitis, a contagious, chronic disease of sheep and goats [3].Several previous studies showed high sequential homology of theC. pseudotuberculosis biovar ovis strains confirming their clonal origin; however, diversity of the clinical signs in sheep and goats and different efficacy of the vaccines suggest that more than one pathogen clone can exist [14].The analysis of sequence data of 16 frequently studied housekeeping genes (atpA,dnaE,dnaK,fusA,leuA,odhI,rpoB,atpD,groES,groEL1,groEL2, infB,recA,recN,rpoA, andsodA) of 15C. pseudotuberculosis, 13C. diphtheriae, andC. ulcerans genomes from the GenBank proved to be related and all studied genes could be used to differentiateC. diphtheriae, C. ulcerans, andC. pseudotuberculosis strains. All these genes allow the differentiation of biotype ovis and biotype equi strains ofC. pseudotuberculosis but for detailed examination ofC. pseudotuberculosis biovar ovis field isolates four genes (dnaK,groEL1, infB, andleuA) seemed to have higher differentiation power. The partial sequence analysis of adequate genes delineated phylogenetic trees with various topology and depth of branches. The highest resolution and topology of the tree were obtained with thednaK sequences.The clusters could be explained by movement of breeding animals, but no epidemiological connection was found between the examinedC. pseudotuberculosis strains. The distance between the geographical place of isolation and the year of the isolation do not support any epidemiological connection between the strains, so circulation of several clones ofC. pseudotuberculosis biotype ovis was verified.According to our data, multilocus sequence typing can differentiateC. pseudotuberculosis and the most importantCorynebacterium species, and examination of selected genes helps to differentiate the two biotypes ofC. pseudotuberculosis, and it can be used for epidemiological follow-up of these strains.



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*Source: 1762162-2017-10-11.xml*