Previous Article | Next Article 
Journal of Clinical Microbiology, October 2007, p. 3439-3442, Vol. 45, No. 10
0095-1137/07/$08.00+0 doi:10.1128/JCM.01411-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.
Polymorphisms in gyrA and gyrB Genes among Mycobacterium avium subsp. paratuberculosis Type I, II, and III Isolates
E. Castellanos,1
A. Aranaz,1*
B. Romero,1
L. de Juan,1
J. Alvarez,1
J. Bezos,1
S. Rodríguez,1
K. Stevenson,2
A. Mateos,1 and
L. Domínguez1
Departamento de Sanidad Animal, Laboratorio de Vigilancia Sanitaria Veterinaria, Facultad de Veterinaria, Universidad Complutense de Madrid, Avda. Puerta de Hierro s/n, 28040 Madrid, Spain,1
Moredun Research Institute, Pentlands Science Park, Penicuik EH26 OPZ, Scotland, United Kingdom2
Received 13 July 2007/
Accepted 22 July 2007

ABSTRACT
The analysis of the
gyrA and
gyrB genes of a panel of
Mycobacterium avium subsp.
paratuberculosis isolates from types I, II, and
III detected type-specific single nucleotide polymorphisms.
Based on these results, we developed a PCR and restriction enzyme
analysis to discriminate type I and III isolates. The application
of this technique would be the unique strategy to characterize
these strains when there is not enough bacterial growth to perform
pulsed-field gel electrophoresis and IS
900 restriction fragment
length polymorphism.

TEXT
Mycobacterium avium subsp.
paratuberculosis is responsible for
paratuberculosis (Johne's disease), a chronic inflammation of
the gastrointestinal tract that affects mainly livestock and
wild ruminants. In addition, this microorganism is under study
due to its possible implication as the etiological agent in
Crohn's disease, affecting human beings (
6,
21).
M. avium subsp. paratuberculosis strains have been classified into three major groups (sheep [type I], cattle [type II], and intermediate [type III]) based on their growth rates and molecular characterizations by IS900 restriction fragment length polymorphism (RFLP) (23) and pulsed-field gel electrophoresis (PFGE), respectively (10, 28). Rapid tools have been designed to distinguish type II from type I (7, 11); however, there is not a quick technique to further distinguish between types I and III. Therefore, when there is not enough bacterial growth to perform RFLP or PFGE, these isolates cannot be accurately classified, and they are named as type I/III (8).
Single nucleotide polymorphisms (SNPs) are changes in a single base at a specific position in the genome (16, 30). A correlation of SNP with phenotypic diversity has been established for some mycobacterial species, encouraging its use in order to distinguish among them at the level of bacterial strains (1, 4, 12, 18).
The genes gyrA and gyrB within the genus Mycobacterium have been analyzed in order to perform phylogenetic studies (2, 3, 14). The gyrB gene has been proposed to be a suitable phylogenetic marker, due to its average substitution rate at synonymous sites of 0.7% to 0.8% per 1 million years, much lower than that seen for some other phylogenetic markers, such as the 16S rRNA gene (14). In previous studies, analysis of polymorphisms in this gene has been used to differentiate between closely related strains (22).
Therefore, the aim of our study was the analysis of SNPs in the gyrA and gyrB genes to find a relationship with the subdivision of M. avium subsp. paratuberculosis strains. The combination of SNPs found in each of the genes was able to divide types I, II, and III. Furthermore, we developed a PCR and restriction enzyme analysis (PCR-REA) to identify type I and III strains.
Mycobacterium avium subsp. paratuberculosis isolates.
A panel of 20 M. avium subsp. paratuberculosis isolates was selected according to their difference in terms of strain type (type I [n = 5], type II [n = 7], type III [n = 5], and type I/III [n = 3]), geographic origin (Spain, Scotland, and Denmark), and host distribution (Table 1). These isolates were obtained from a pool of ileocecal valve and mesenteric lymph node samples as described in previous studies (13) and were subcultured onto selective growth media with mycobactin J (Dismalab, Madrid, Spain) (9).
Colonies were recovered from the tubes and submitted to a PCR
analysis for the presence of an IS
900 fragment (
15,
19). Moreover,
IS
1311 PCR-REA (
17) for every isolate and PFGE were performed
to confirm the strain type.
Analysis of sequences of the gyrA and gyrB genes.
Primers (Table 2) were designed using Primer 3software (http://biotools.umassmed.edu/bioapps/primer3_www.cgi) for both the gyrA gene (GenBank accession no. 2720426 [genome number NC_002944]; http://www.ncbi.nlm.nih.gov/GenBank) and the gyrB gene (GenBank accession no. 2717659). PCR was carried out using a HotStart Taq DNA polymerase kit (QIAGEN GmbH, Hilden, Germany). Each tube contained 5 µl of DNA sample, 1x buffer, 200 µM deoxynucleoside triphosphate (Biotools, B&M Labs, S.A., Madrid, Spain), 1x Q solution, 1 µl of each primer (8 µM), and 0.625 U of HotStart polymerase. PCR was undertaken with a MyCycler thermal cycler (Bio-Rad) under the following conditions: denaturation at 94°C for 15 min and 35 cycles of denaturation at 94°C for 1 min, annealing at 60°C for 1 min, and extension at 72°C for 1 min, with a final cycle of extension at 72°C for 5 min.
Purification of the PCR product was undertaken with a QIAquick
PCR purification kit (QIAGEN GmbH), and the product was sequenced
using an ABI Prism 3730 DNA sequencer (Applied Biosystems) (CIB
Sequencing Facilities, Madrid, Spain). Chromatograms of forward
and reverse sequences were then evaluated with Biological Sequence
Alignment Editor software and compared with Mega 3.1 results
to establish complete alignments for all the isolates. In addition,
every sequence was submitted to nucleotide-nucleotide BLAST
against
M. avium subsp.
paratuberculosis K-10 to identify the
locations of SNPs.
The analysis of the sequences revealed a total of nine SNPs, four of them representing a change in coded amino acids (Table 3) . In the gyrA gene, the SNPs were located at positions 868, 1653, 1822, and 1986; two of them (at positions 868 and 1653) were implicated in nonsynonymous modifications, changing from hydrophilic amino acids into amino acids belonging to the basic group. The sequencing of the gyrB gene in the studied isolates showed five SNPs at positions 108, 264, 494, 1353, and 1626; a total of two represented a change in coded amino acids (at positions 264 and 494) (Table 3).
View this table:
[in this window]
[in a new window]
|
TABLE 3. SNPs found in gyrA and gyrB genes and encoded amino acids for M. avium subsp. paratuberculosis strain K-10 and types I, II, III, and I/III
|
Differentiation of M. avium subsp. paratuberculosis types.
The combination of SNPs found in this study within the
gyrA and
gyrB genes separately allow classification into types I,
II, and III. In type I, the SNP found at nucleotide 868 of the
gyrA gene resulted in an amino acid change (glutamate), while
in types II, III, and I/III, a G was found upon sequencing.
Type III and I/III isolates presented two specific SNPs. The
first was located at position 1986 of the
gyrA gene, with a
T sequenced instead of the C found in types I and II; the second
SNP was found at base 1626 of the
gyrB gene, with a change in
a T instead of the C found in types I and II. Type II isolates
were distinguished by six specific SNPs, which were located
at nucleotides 1653 and 1822 of the
gyrA gene and at nucleotides
108, 264, 494, and 1353 of the
gyrB gene.
M. avium subsp. paratuberculosis type differentiation by PCR-REA.
A PCR-REA was designed to detect the polymorphism in the gyrB gene at position 1626, the SNP that allowed types I and II to be distinguished from type III. The 897-bp PCR products were submitted to restriction analysis with the enzyme Hpy188-III (New England Biolabs). Digestion was performed with 10 µl of PCR products, 5 U of enzyme, 1x NE buffer 4, and 0.5 µl of 100 µg/ml bovine serum albumin. Afterwards, digestion products were analyzed by electrophoresis in a 2.5% agarose gel with a molecular size marker (100-bp ladder) (Biotools, B&M Labs S.A.) and stained with iQ SYBR green supermix (Bio-Rad).
The restriction led to a four-band pattern (551, 153, 112, and 80 bp) for type I and type II isolates in which the codon ATC was present and to three bands (551, 192, and 153 bp) for isolates of type III (Fig. 1). The pattern obtained with type I/III isolates matched the pattern characteristic of type III isolates.
The development of molecular techniques to identify
M. avium subsp.
paratuberculosis strains that are characterized by extremely
low growth rates and are refractory to culture (types I and
III) would be useful for diagnostic laboratories. We have based
our study on the presence of SNPs, a relatively new molecular
strategy with the advantages of being inexpensive and having
a high-throughput production (
29). For instance, SNP analysis
has been used recently with
M. avium subsp.
paratuberculosis isolates to differentiate cattle (type II) and sheep (type I/III)
isolates (
18,
25).
The most useful finding from the sequencing of the gyrB gene was the SNP found at nucleotide 1626, which was able to distinguish type III from the other types and was susceptible to PCR-REA. This finding is a valuable tool to accurately identify these isolates without the need to perform time-consuming protocols. Until this time, the differentiation between types I and III was possible only by using PFGE and IS900 RFLP, which require substantial amounts of DNA (10, 28); this is often a limitation due to the fastidious growth requirements and long incubation periods characteristic of these strains. The combination of SNPs of the isolates previously named as type I/III matched the pattern found in type III isolates. This result is epidemiologically consistent with our previous finding that no type I isolates have been found in the Spanish geographic area from which these isolates were collected (8, 10). However, type I has been reported to be present in other areas (26).
There was also a combination of polymorphisms that characterized type II isolates; three of them had already been described (18). However, these are of less practical usefulness, because the identification of type II (cattle) can be performed by the PCR described by Collins et al. (7), by the IS1311 PCR-REA (17), or by type I-specific locus PCRs performed following the protocol of Dohmann et al. (11).
These results would suggest that the SNPs are type specific. The gyrA and gyrB sequences of the type II isolates were identical of those from M. avium subsp. paratuberculosis strain K-10. Also, both gyrA and gyrB sequences were identical among all isolates within a type group, despite their different geographic areas or host origins. Two of the five substitutions found in the gyrB gene were nonsynonymous, while the substitutions present in the members of the M. tuberculosis complex were synonymous (14, 22). The origin of the changes found at the M. avium subsp. paratuberculosis types may be caused by the divergent evolution or may have been developed by selective pressure from antibiotic treatment.
PCR-REA assays would be of great advantage in testing M. avium subsp. paratuberculosis DNA directly extracted from tissues, blood, milk, or other samples of human or veterinary origin that are culture negative and isolates that are not easily subcultured (5, 24, 27). These assays will help to improve the knowledge and characterization of the role of these pathogens during the infection, due to the possible relationship between M. avium subsp. paratuberculosis type and pathogenesis (9, 20). Nowadays, despite the worldwide prevalence of the infection, there is limited information on M. avium subsp. paratuberculosis isolates due to the absence of quick molecular tools. This may be the reason why, at the present time, type III isolates have been reported only in Spain (10). We think this technique complements the already existing fast molecular techniques, but more studies pertaining to different geographic areas would be convenient to assess the usefulness of this technique as a routine test for identification purposes.
In addition, the gyrA and gyrB genes, in combination with other selected target genes, could be used as phylogenetic markers to gain an insight into the taxonomy and evolution of the subspecies, as has been achieved for the M. tuberculosis complex. These results are preliminary due to the limited sample size and the restricted geographic origin of the isolates. A widespread and definitive epidemiological study should be undertaken to validate these results and to test the usefulness of this technique.
In summary, the polymorphisms found in the gyrA and gyrB genes are specific for types I, II, and III of M. avium subsp. paratuberculosis. The SNP present in the gyrB gene was susceptible to PCR-REA, and to our knowledge, this is the first description of a fast molecular tool able to divide M. avium subsp. paratuberculosis strains into these three major groups.
Nucleotide sequence accession numbers.
The GenBank accession number for the gyrA partial sequence from type I is EU029115, and that for the partial sequence from type III is EU029113. The accession number for the gyrB partial sequence from type I is EU029112, and that for the partial sequence from type III is EU129114.

ACKNOWLEDGMENTS
This research was funded by project AGL2005-07792 of the Spanish
Ministry of Science and Technology, EU Project ParaTBTools FP6-2004-FOOD-3B-023106,
and by the Spanish Ministry of Agriculture, Fisheries and Food.
E.C. is the recipient of a grant (AP2005-0696 GAN) from the
Ministry of Education and Culture.
We thank the staff of SADNA (C.I.B. Madrid) for sequencing. We appreciate the technical help of F. Lozano and N. Moya. We are grateful to D. Morey for careful revision of the manuscript. We thank L. Carbajo, J. L. Paramio, and J. L. Sáez-Llorente for their continuous encouragement.

FOOTNOTES
* Corresponding author. Mailing address: Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Avda. Puerta de Hierro s/n, 28040 Madrid, Spain. Phone: 34913943721. Fax: 34913943795. E-mail: address:
alaranaz{at}vet.ucm.es 
Published ahead of print on 1 August 2007. 

REFERENCES
1 - Alland, D., T. S. Whittam, M. B. Murray, M. D. Cave, M. H. Hazbon, K. Dix, M. Kokoris, A. Duesterhoeft, J. A. Eisen, C. M. Fraser, and R. D. Fleischmann. 2003. Modeling bacterial evolution with comparative- genome-based marker systems: application to Mycobacterium tuberculosis evolution and pathogenesis. J. Bacteriol. 185:3392-3399.[Abstract/Free Full Text]
2 - Aranaz, A., D. Cousins, A. Mateos, and L. Dominguez. 2003. Elevation of Mycobacterium tuberculosis subsp. caprae Aranaz et al. 1999 to species rank as Mycobacterium caprae comb. nov., sp. nov. Int. J. Syst. Evol. Microbiol. 53:1785-1789.[Abstract/Free Full Text]
3 - Baker, L., T. Brown, M. C. Maiden, and F. Drobniewski. 2004. Silent nucleotide polymorphisms and a phylogeny for Mycobacterium tuberculosis. Emerg. Infect. Dis. 10:1568-1577.[Medline]
4 - Brosch, R., S. V. Gordon, M. Marmiesse, P. Brodin, C. Buchrieser, K. Eiglmeier, T. Garnier, C. Gutierrez, G. Hewinson, K. Kremer, L. M. Parsons, A. S. Pym, S. Samper, S. D. Van, and S. T. Cole. 2002. A new evolutionary scenario for the Mycobacterium tuberculosis complex. Proc. Natl. Acad. Sci. USA 99:3684-3689.[Abstract/Free Full Text]
5 - Buergelt, C. D., and J. E. Williams. 2004. Nested PCR on blood and milk for the detection of Mycobacterium avium subsp paratuberculosis DNA in clinical and subclinical bovine paratuberculosis. Aust. Vet. J. 82:497-503.[Medline]
6 - Bull, T. J., E. J. McMinn, K. Sidi-Boumedine, A. Skull, D. Durkin, P. Neild, G. Rhodes, R. Pickup, and J. Hermon-Taylor. 2003. Detection and verification of Mycobacterium avium subsp. paratuberculosis in fresh ileocolonic mucosal biopsy specimens from individuals with and without Crohn's disease. J. Clin. Microbiol. 41:2915-2923.[Abstract/Free Full Text]
7 - Collins, D. M., M. De Zoete, and S. M. Cavaignac. 2002. Mycobacterium avium subsp. paratuberculosis strains from cattle and sheep can be distinguished by a PCR test based on a novel DNA sequence difference. J. Clin. Microbiol. 40:4760-4762.[Abstract/Free Full Text]
8 - de Juan, L., J. Alvarez, A. Aranaz, A. Rodriguez, B. Romero, J. Bezos, A. Mateos, and L. Dominguez. 2006. Molecular epidemiology of types I/III strains of Mycobacterium avium subspecies paratuberculosis isolated from goats and cattle. Vet. Microbiol. 115:102-110.[CrossRef][Medline]
9 - de Juan, L., J. Alvarez, B. Romero, J. Bezos, E. Castellanos, A. Aranaz, A. Mateos, and L. Dominguez. 2006. Comparison of four different culture media for isolation and growth of type II and type I/III Mycobacterium avium subsp. paratuberculosis strains isolated from cattle and goats. Appl. Environ. Microbiol. 72:5927-5932.[Abstract/Free Full Text]
10 - de Juan, L., A. Mateos, L. Dominguez, J. M. Sharp, and K. Stevenson. 2005. Genetic diversity of Mycobacterium avium subspecies paratuberculosis isolates from goats detected by pulsed-field gel electrophoresis. Vet. Microbiol. 106:249-257.[CrossRef][Medline]
11 - Dohmann, K., B. Strommenger, K. Stevenson, L. de Juan, J. Stratmann, V. Kapur, T. J. Bull, and G. F. Gerlach. 2003. Characterization of genetic differences between Mycobacterium avium subsp. paratuberculosis type I and type II isolates. J. Clin. Microbiol. 41:5215-5223.[Abstract/Free Full Text]
12 - Filliol, I., A. S. Motiwala, M. Cavatore, W. Qi, M. H. Hazbon, M. Bobadilla del Valle, J. Fyfe, L. Garcia-Garcia, N. Rastogi, C. Sola, T. Zozio, M. I. Guerrero, C. I. Leon, J. Crabtree, S. Angiuoli, K. D. Eisenach, R. Durmaz, M. L. Joloba, A. Rendon, J. Sifuentes-Osornio, A. Ponce de León, M. D. Cave, R. Fleischmann, T. S. Whittam, and D. Alland. 2006. Global phylogeny of Mycobacterium tuberculosis based on single nucleotide polymorphism (SNP) analysis: insights into tuberculosis evolution, phylogenetic accuracy of other DNA fingerprinting systems, and recommendations for a minimal standard SNP set. J. Bacteriol. 188:759-772.[Abstract/Free Full Text]
13 - Greig, A., K. Stevenson, V. Perez, A. A. Pirie, J. M. Grant, and J. M. Sharp. 1997. Paratuberculosis in wild rabbits (Oryctolagus cuniculus). Vet. Rec. 140:141-143.[Abstract/Free Full Text]
14 - Kasai, H., T. Ezaki, and S. Harayama. 2000. Differentiation of phylogenetically related slowly growing mycobacteria by their gyrB sequences. J. Clin. Microbiol. 38:301-308.[Abstract/Free Full Text]
15 - Kunze, Z. M., F. Portaels, and J. J. McFadden. 1992. Biologically distinct subtypes of Mycobacterium avium differ in possession of insertion sequence IS901. J. Clin. Microbiol. 30:2366-2372.[Abstract/Free Full Text]
16 - Maiden, M. C., J. A. Bygraves, E. Feil, G. Morelli, J. E. Russell, R. Urwin, Q. Zhang, J. Zhou, K. Zurth, D. A. Caugant, I. M. Feavers, M. Achtman, and B. G. Spratt. 1998. Multilocus sequence typing: a portable approach to the identification of clones within populations of pathogenic microorganisms. Proc. Natl. Acad. Sci. USA 95:3140-3145.[Abstract/Free Full Text]
17 - Marsh, I., R. Whittington, and D. Cousins. 1999. PCR-restriction endonuclease analysis for identification and strain typing of Mycobacterium avium subsp. paratuberculosis and Mycobacterium avium subsp. avium based on polymorphisms in IS1311. Mol. Cell. Probes 13:115-126.[CrossRef][Medline]
18 - Marsh, I. B., and R. J. Whittington. 2007. Genomic diversity in Mycobacterium avium: single nucleotide polymorphisms between the S and C strains of M. avium subsp. paratuberculosis and with M. a. avium. Mol. Cell. Probes 21:66-75.[CrossRef][Medline]
19 - Millar, D. S., S. J. Withey, M. L. Tizard, J. G. Ford, and J. Hermon-Taylor. 1995. Solid-phase hybridization capture of low-abundance target DNA sequences: application to the polymerase chain reaction detection of Mycobacterium paratuberculosis and Mycobacterium avium subsp. silvaticum. Anal. Biochem. 226:325-330.[CrossRef][Medline]
20 - Motiwala, A. S., H. K. Janagama, M. L. Paustian, X. Zhu, J. P. Bannantine, V. Kapur, and S. Sreevatsan. 2006. Comparative transcriptional analysis of human macrophages exposed to animal and human isolates of Mycobacterium avium subsp. paratuberculosis with diverse genotypes. Infect. Immun. 74:6046-6056.[Abstract/Free Full Text]
21 - Naser, S. A., G. Ghobrial, C. Romero, and J. F. Valentine. 2004. Culture of Mycobacterium avium subspecies paratuberculosis from the blood of patients with Crohn's disease. Lancet 364:1039-1044.[CrossRef][Medline]
22 - Niemann, S., D. Harmsen, S. Rusch-Gerdes, and E. Richter. 2000. Differentiation of clinical Mycobacterium tuberculosis complex isolates by gyrB DNA sequence polymorphism analysis. J. Clin. Microbiol. 38:3231-3234.[Abstract/Free Full Text]
23 - Pavlik, I., A. Horvathova, L. Dvorska, J. Bartl, P. Svastova, R. du Maine, and I. Rychlik. 1999. Standardisation of restriction fragment length polymorphism analysis for Mycobacterium avium subspecies paratuberculosis. J. Microbiol. Methods 38:155-167.[CrossRef][Medline]
24 - Sechi, L. A., A. M. Scanu, P. Molicotti, S. Cannas, M. Mura, G. Dettori, G. Fadda, and S. Zanetti. 2005. Detection and isolation of Mycobacterium avium subspecies paratuberculosis from intestinal mucosal biopsies of patients with and without Crohn's disease in Sardinia. Am. J. Gastroenterol. 100:1529-1536.[CrossRef][Medline]
25 - Semret, M., C. Y. Turenne, and M. A. Behr. 2006. Insertion sequence IS900 revisited. J. Clin. Microbiol. 44:1081-1083.[Abstract/Free Full Text]
26 - Sevilla, I., J. M. Garrido, M. Geijo, and R. A. Juste. 2007. Pulsed-field gel electrophoresis profile homogeneity of Mycobacterium avium subsp. paratuberculosis isolates from cattle and heterogeneity of those from sheep and goats. BMC Microbiol. 7:18.[CrossRef][Medline]
27 - Sivakumar, P., B. N. Tripathi, and N. Singh. 2005. Detection of Mycobacterium avium subsp. paratuberculosis in intestinal and lymph node tissues of water buffaloes (Bubalus bubalis) by PCR and bacterial culture. Vet. Microbiol. 108:263-270.[CrossRef][Medline]
28 - Stevenson, K., V. M. Hughes, L. de Juan, N. F. Inglis, F. Wright, and J. M. Sharp. 2002. Molecular characterization of pigmented and nonpigmented isolates of Mycobacterium avium subsp. paratuberculosis. J. Clin. Microbiol. 40:1798-1804.[Abstract/Free Full Text]
29 - Ulgen, A., and W. Li. 2005. Comparing single-nucleotide polymorphism marker-based and microsatellite marker-based linkage analyses. BMC Genet. 6(Suppl. 1):S13.[CrossRef][Medline]
30 - Urwin, R., and M. C. Maiden. 2003. Multi-locus sequence typing: a tool for global epidemiology. Trends Microbiol. 11:479-487.[CrossRef][Medline]
Journal of Clinical Microbiology, October 2007, p. 3439-3442, Vol. 45, No. 10
0095-1137/07/$08.00+0 doi:10.1128/JCM.01411-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.
This article has been cited by other articles:
-
Castellanos, E., Aranaz, A., de Juan, L., Alvarez, J., Rodriguez, S., Romero, B., Bezos, J., Stevenson, K., Mateos, A., Dominguez, L.
(2009). Single Nucleotide Polymorphisms in the IS900 Sequence of Mycobacterium avium subsp. paratuberculosis Are Strain Type Specific. J. Clin. Microbiol.
47: 2260-2264
[Abstract]
[Full Text]
-
Castellanos, E., Aranaz, A., Gould, K. A., Linedale, R., Stevenson, K., Alvarez, J., Dominguez, L., de Juan, L., Hinds, J., Bull, T. J.
(2009). Discovery of Stable and Variable Differences in the Mycobacterium avium subsp. paratuberculosis Type I, II, and III Genomes by Pan-Genome Microarray Analysis. Appl. Environ. Microbiol.
75: 676-686
[Abstract]
[Full Text]
-
Griffiths, T. A., Rioux, K., De Buck, J.
(2008). Sequence Polymorphisms in a Surface PPE Protein Distinguish Types I, II, and III of Mycobacterium avium subsp. paratuberculosis. J. Clin. Microbiol.
46: 1207-1212
[Abstract]
[Full Text]