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Journal of Clinical Microbiology, July 2001, p. 2594-2597, Vol. 39, No. 7
0095-1137/01/$04.00+0 DOI: 10.1128/JCM.39.7.2594-2597.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.
Detection of RTX Toxin Gene in Vibrio
cholerae by PCR
K. H.
Chow,1
T. K.
Ng,2
K. Y.
Yuen,1 and
W. C.
Yam1,*
Department of Microbiology, The University of
Hong Kong,1 and Department of
Pathology, Princess Margaret Hospital,2 Hong
Kong SAR, China
Received 30 January 2001/Returned for modification 6 March
2001/Accepted 24 April 2001
 |
ABSTRACT |
A PCR that amplifies a recently discovered Vibrio
cholerae RTX (repeat in toxin) toxin gene was developed. Among
166 clinical and environmental isolates of V. cholerae
causing epidemics and sporadic cases of cholera in various parts of the
world, all were found to be toxigenic by both PCR and HEp-2 cell
cytotoxicity assay. Standard strains of the classical biotype
containing a deletion within the gene cluster exhibited negative
results by both assays. This is the first rapid genotyping method for
differentiation of V. cholerae O1 classical biotype
strains from El Tor biotype strains as well as strains of other non-O1
serogroups including serogroup O139. The PCR assay that was developed
also specifically detects RTX toxin genes in V.
cholerae, as clinical isolates of Vibrio
parahaemolyticus, diarrheagenic Escherichia
coli, Aeromonas species, and
Plesiomonas species were all negative by the RTX toxin-specific PCR as well as the HEp-2 cytotoxicity assay. These findings highlight the characteristics of the RTX toxins in V. cholerae. Their role in the pathogenicity of the bacterium
requires further investigation.
| |
INTRODUCTION |
Vibrio cholerae is an
important cause of diarrheal disease in many parts of Asia and Africa.
It is the only enteric pathogen that has the potential to produce
pandemics of disease and is of immense public health importance.
Cholera is caused by V. cholerae serogroup O1, which has
been highly prevalent in Southeast Asia in the past 20 years (2,
5, 13). V. cholerae O1 biotype El Tor was responsible
for the cholera epidemic in Hong Kong between 1986 and 1997 (7,
22, 23). Although cholera toxin-producing V. cholerae
O139 has been sweeping across the Indian subcontinent since 1992, epidemic spread of this novel strain of V. cholerae has not
occurred in Hong Kong since the first imported case was detected in May
1993 (21, 27).
Traditionally, life-threatening diarrhea associated with the cholera
syndrome is attributed to massive luminal secretion of electrolytes and
water from enterocytes, with elevated cyclic AMP levels induced by the
cholera toxin (CT). CT is encoded by the ctxA and
ctxB genes of the core element (8). A novel
toxin in V. cholerae that belongs to the RTX (repeat in
toxin) family of toxins, which are generally produced by several
pathogenic gram-negative bacteria (10), was recently
discovered. The RTX toxins represent a family of important virulence
factors that have disseminated widely among gram-negative bacteria
(1). The RTX toxin gene cluster in V. cholerae
encodes the presumptive cytotoxin (rtxA), an acyltransferase
(rtxC), and an associated ATP-binding cassette transporter
system (RtxB and RtxD, two proteins for toxin transportation) (Fig.
1). It is physically linked to the core
element in the V. cholerae genome, although its activity is
independent of the core element (10). Phenotypically,
these genes are proven to be associated with cytotoxicity in HEp-2
cells. In the study described here, a highly specific PCR was developed to identify this toxin gene in more than 100 clinical and environmental isolates of V. cholerae causing sporadic and epidemic cases
of cholera in various parts of the world.
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FIG. 1.
Genomic structure of RTX toxin element in V.
cholerae. Adapted from reference 10, with
permission from the National Academy of Sciences, U.S.A.
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|
(This work was done in partial fulfillment of the M.Phil. degree at the
University of Hong Kong by K. H. Chow.).
| |
MATERIALS AND METHODS |
Sources of strains.
A total of 166 V. cholerae
isolates from five different regions were included in our study (Table
1). The majority of the isolates were
V. cholerae O1 El Tor, O139, and non-O1 serogroup strains
collected from patients or the environment over a decade in Hong Kong
(7, 21, 22, 23, 27). The remaining 51 clinical isolates of
O1 El Tor and O139 were isolated from Hong Kong, China;
Shenzhen, China; Singapore; Thailand; and Ukraine from 1991 to 1999. In
addition, five strains each of diarrheagenic Escherichia
coli (three isolates of verocytotoxigenic E. coli and
two isolates of enteropathogenic E. coli), Vibrio
parahaemolyticus, Aeromonas species, and
Plesiomonas species isolated from patients suffering from
diarrhea in Hong Kong were also included for comparative study
(18, 19, 20).
PCR for rtxA, rtxC, and
ctxB.
DNA from all purified strains was prepared
from overnight liquid cultures grown in 5 ml of brain heart infusion
broth at 37°C. Cell pellets from 1 ml of culture were washed with
normal saline, centrifuged, and resuspended in 100 µl of sterile
Milli-Q H2O. After the suspension was
heated in a dry bath at 85°C for 15 min, the pellet was spun down at
15,900 × g for 15 min at 4°C, and the supernatant
was saved for use as the DNA template in the PCR.
Two pairs of primers were derived from the
rtxA and
rtxC genes of
V. cholerae N16961. The sequences
of the primers extended
within the deletion region of the RTX
gene cluster in classical
biotype strain O395 (Fig.
1). PCR amplified a
417-bp product of
the
rtxA gene (primers
rtxA-F [5'-CTG AAT ATG AGT GGG TGA CTT
ACG-3']
and
rtxA-R [5'GTG TAT TGT TCG ATA TCC GCT
ACG-3']) and
a 263-bp product of the
rtxC gene
(primers
rtxC-F [5'-CGA CGA
AGA TCA TTG ACG AC-3']
and
rtxC-R [5'-CAT CGT CGT TAT GTG GTT
GC-3']). The total reaction volume was 25 µl, which contained
3 µl of DNA template and 2.5 µl of 10× PCR buffer (final
concentrations,
1.5 mM MgCl
2 and 0.4 mg of bovine
serum albumin per ml [Applied
Biosystems, Foster City, Calif.]), 1 µM primers, deoxynucleoside
triphosphates at a concentration of 0.2 mM, 1 U of AmpliTaq Gold
polymerase (Perkin-Elmer), and 1 drop of
mineral oil. After pretreatment
by heating of the mixture at 94°C for
12 min to activate the enzyme
polymerase prior to the cycling reaction,
DNA amplification was
carried out for 30 cycles at 94°C for 1 min,
55°C for 1 min, and
72°C for 1 min. An extension period of 72°C
for 10 min was added
at the end of the cycling reaction. For product
detection, 5 µl
of the PCR mixture was subjected to electrophoresis
in a 2% agarose
gel.
The amplification of a 460-bp
ctxB gene (primers
ctxB2 [5'-GAT ACA CAT AAT AGA ATT
AAG GAT G-3'] and
ctxB3
[5'-GGT TGC TTC
TCA TCA TCG AAC CAC-3']) from the sample
strains was performed
as described previously (
3,
12).
Cytotoxicity and CT assays.
All bacterial strains were
tested to determine whether they had a cytopathic effect on HEp-2
cells, as described previously (10). Briefly, HEp-2 cells
were cultured in RPMI 1640 medium (Gibco, Grand Island, N.Y.) with 10%
fetal calf serum and supplement (without antibiotics) and were seeded
onto dishes for assay. Washed bacterial cultures were added to the
HEp-2 cells, and the dishes were incubated at 37°C in 5%
CO2 for 1 h. A positive result was indicated
by rounding up and detachment of monolayer HEp-2 cells from the culture dishes.
Active CT production was also performed by the VET-RPLA (Oxoid
Ltd., Basingstoke, United Kingdom) assay, with modifications,
as
described previously (
24). Briefly, polymyxin B was added
to the overnight bacterial cultures, followed by incubation at
37°C
for 4 h with shaking. After centrifugation, the supernatants
were
diluted in V-type microtiter plates in duplicate until the
last well
contained diluent only. Latex suspensions sensitized
with
antibodies to CT were added to each well and were left undisturbed
at
room temperature for 20 to 24 h. Agglutination was examined
macroscopically and
recorded.
| |
RESULTS |
All 166 clinical and environmental strains of V. cholerae were collected from 1986 to 1999 in Hong Kong, China,
Singapore, Thailand, and Ukraine (Table 1). V. cholerae
isolates of the O1 El Tor, O139, and non-O1 serogroups exhibited
positive PCR results for both rtxA and rtxC genes
(Fig. 2). Concurrently, all these
isolates were also positive by the HEp-2 cytotoxicity assay. Complete
concordance was found between the genotypic and the phenotypic expressions of the RTX toxins in all strains tested, indicating the
integrity of the RTX toxin gene cluster among the strains. Although no
clinical strain of the V. cholerae classical biotype was
collected during the period studied, the rtxA and
rtxC genes were not amplified from standard V. cholerae classical biotype strains, strains ATCC 9458 and ATCC
11628. These two classical strains also exhibited negative
results by the HEp-2 cytotoxicity assay. Except for the non-O1
serogroups, all V. cholerae O1 and O139 isolates were
positive for CT by VET-RPLA and PCR assay. Five strains each of
V. parahaemolyticus, diarrheagenic E. coli, Aeromonas species, and Plesiomonas species
included in the present study exhibited negative results by all PCR and
toxin assays.
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FIG. 2.
Agarose gel electrophoresis of PCR products of
rtxA (lanes a to d) and rtxC (lanes A to
D). Lanes a and A, V. cholerae O1 El Tor; lanes b and B,
V. cholerae O139; lanes c and C, V.
cholerae non-O1; lanes d and D, V. cholerae
classical strain ATCC 9458; lanes M, molecular mass markers
(BsuRI-digested  X174 DNA).
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| |
DISCUSSION |
On the basis of the discovery of RTX toxins in V. cholerae, we developed two assays specific for rtxA and
rtxC and screened for the presence of functional RTX toxin
genes in our collection of strains obtained from various parts of the
world from 1986 to 1999. Our findings for chronologically and
geographically disparate strains indicate that the presence of an
intact RTX toxin gene cluster is consistent with the phenotypic
expression of cytotoxic activity in all these isolates. Standard
strains of the classical biotype exhibited negative results by both PCR
and cytotoxicity assays, which was explained by the deletion of the
gene cluster. In addition, the PCR detection assay described here was
highly specific for V. cholerae, as all clinical isolates of
V. parahaemolyticus, diarrheagenic E. coli,
Aeromonas species, and Plesiomonas species exhibited negative results.
Although genotypic methods like PCR of the ctx gene are
available for the rapid identification of toxigenic V. cholerae, definitive identification of the classical and El Tor
biotypes within the O1 serogroup relies on conventional biochemical
methods, which are tedious and time-consuming. Although only two
V. cholerae classical strains were included in the present
study, the PCR assays developed for rtxA or rtxC,
when used in combination with PCR for CT, not only identify
CT-producing V. cholerae but also differentiate the biotypes
of strains within the V. cholerae O1 serogroup.
While CT is a principal virulence factor for V. cholerae,
the contribution of the RTX toxins to its pathogenesis requires further
investigation. At present, the cytolytic RTX toxins represent a family
of important virulence factors for organisms that produce the toxin.
Good evidence of the role of the hemolysin of E. coli as a
cause of extraintestinal infections is available
(17). In our study, the rtx gene cluster was
absent only from the V. cholerae classical O1 serogroup
strain, which has greater epidemic potential than strains of the other
serogroups, despite its displacement by the El Tor biotype since
the seventh pandemic. Nonepidemic V. cholerae non-O1
serogroup strains, which cause only sporadic, milder cases of diarrhea,
do secrete the RTX cytotoxins but do not secrete CT. Several groups
proposed that virulence factors account for the clinical manifestations
of diarrhea caused by non-O1 serogroup strains (6, 15, 25,
26). One distinct finding indicated that V. cholerae
non-O1 serogroup strains caused necrosis of the luminal epithelium in
the colon and mild inflammatory cell infiltration in the adjacent
lamina propria (14). Evidence of the inflammatory response
due to a V. cholerae O1 El Tor strain from which all
known toxin genes excluding the rtx gene cluster have been
deleted has also been reported (16). The vacuolating activity of the V. cholerae El Tor hemolysin in nucleated
mammalian cells may be associated with gastrointestinal symptoms caused by nontoxigenic V. cholerae (11). A recent
investigation (4) demonstrated that the RTX toxins of
V. cholerae caused actin depolymerization and cross-linking
in HEp-2 cells. Similar actin rearrangement or condensation was
observed in HEp-2 cells and was caused by a protein encoded by the
eaeA gene of enteropathogenic and hemorrhagic E. coli, leading to the effacement of microvilli, with subsequent hemorrhagic colitis and bloody diarrhea (9). Our findings
highlight the occurrence of RTX toxins in strains of V. cholerae except those exhibiting the classical biotype. Further
investigation is required to determine the role of RTX in the
pathogenicity of V. cholerae.
| |
ACKNOWLEDGMENTS |
We thank the following persons for providing bacterial strains:
Clifford Clark of the National Laboratory for Enteric Pathogens, Bureau
of Microbiology, Laboratory Centre for Disease Control, Ottawa,
Ontario, Canada; T. Kuyyakanond of the Department of Microbiology, Khon
Kaen University, Khon Kaen, Thailand; and Ling Moi Lin of the
Department of Pathology and Laboratory Medicine, Tan Tock Seng
Hospital, Singapore. We also thank K. W. Wong for excellent technical assistance.
| |
FOOTNOTES |
*
Corresponding author. Mailing address: Department of
Microbiology, Queen Mary Hospital, The University of Hong Kong,
Pokfulam, Hong Kong SAR, China. Phone: (852) 2855 4892. Fax: (852) 2855 1241. E-mail: wcyam{at}hkucc.hku.hk.
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REFERENCES |
| 1.
|
Coote, J. G.
1992.
Structural and functional relationships among the RTX toxin determinants of gram-negative bacteria.
FEMS Microbiol. Rev.
8:137-161[Medline].
|
| 2.
|
Dalsgaard, A.,
A. Forslund,
N. V. Tam,
D. X. Vinh, and P. D. Cam.
1999.
Cholera in Vietnam: changes in genotypes and emergence of class I integrons containing aminoglycoside resistance gene cassettes in Vibrio cholerae O1 strains isolated from 1979 to 1996.
J. Clin. Microbiol.
37:734-741[Abstract/Free Full Text].
|
| 3.
|
Fields, P. I.,
T. Popovic,
K. Wachsmuth, and O. Olsvik.
1992.
Use of polymerase chain reaction for detection of toxigenic Vibrio cholerae O1 strains from the Latin American cholera epidemic.
J. Clin. Microbiol.
30:2118-2121[Abstract/Free Full Text].
|
| 4.
|
Fullner, K. J., and J. J. Mekalanos.
2000.
In vivo covalent cross-linking of cellular actin by the Vibrio cholerae RTX toxin.
EMBO J.
19:5315-5323[CrossRef][Medline].
|
| 5.
|
Hoge, C. W.,
L. Bodhidatta,
P. Echeverria,
M. Deesuwan, and P. Kitporka.
1996.
Epidemiologic study of Vibrio cholerae O1 and O139 in Thailand: at the advancing edge of the eighth pandemic.
Am. J. Epidemiol.
143:263-268[Abstract/Free Full Text].
|
| 6.
|
Ichinose, Y.,
K. Yamamoto,
N. Nakasone,
M. J. Tanabe,
T. Takeda,
T. Miwatani, and M. Iwanaga.
1987.
Enterotoxicity of El Tor-like hemolysin of non-O1 Vibrio cholerae.
Infect. Immun.
55:1090-1093[Abstract/Free Full Text].
|
| 7.
|
Kam, K. M.,
T. H. Leung,
Y. Y. Ho,
N. K. Ho, and T. A. Saw.
1995.
Outbreak of Vibrio cholerae O1 in Hong Kong related to contaminated fish tank water.
Public Health
109:389-395[CrossRef][Medline].
|
| 8.
|
Kaper, J. B.,
A. Fasano, and M. Trucksis.
1994.
Toxins of Vibrio cholerae, p. 145-176.
In
I. K. Wachsmuth, P. A. Blake, and I. Olsvik (ed.), Vibrio cholerae and cholera: molecular to global perspectives. American Society for Microbiology, Washington, D. C.
|
| 9.
|
Knutton, S.,
T. Baldwin,
P. H. Williams, and A. S. McNeish.
1989.
Actin accumulation at sites of bacterial adhesion to tissue culture cells: basis of a new diagnostic test for enteropathogenic and enterohemorrhagic Escherichia coli.
Infect. Immun.
57:1290-1298[Abstract/Free Full Text].
|
| 10.
|
Lin, W.,
K. J. Fullner,
R. Clayton,
J. A. Sexton,
M. B. Rogers,
K. E. Calia,
S. B. Calderwood,
C. Fraser, and J. J. Mekalanos.
1999.
Identification of a Vibrio cholerae RTX toxin gene cluster that is tightly linked to the cholera toxin prophage.
Proc. Natl. Acad. Sci. USA
96:1071-1076[Abstract/Free Full Text].
|
| 11.
|
Mitra, R.,
P. Figueroa,
A. K. Mukhopadhyay,
T. Shimada,
Y. Takeda,
D. E. Berg, and G. B. Nair.
2000.
Cell vacuolation, a manifestation of the El Tor hemolysin of Vibrio cholerae.
Infect. Immun.
68:1928-1933[Abstract/Free Full Text].
|
| 12.
|
Olsvik, O.,
J. Wahlberg,
B. Petterson,
M. Uhlen,
T. Popovic,
I. K. Wachsmuth, and P. I. Fields.
1993.
Use of automated sequencing of polymerase chain reaction-generated amplicons to identify three types of cholera toxin subunit B in Vibrio cholerae O1 strains.
J. Clin. Microbiol.
31:22-25[Abstract/Free Full Text].
|
| 13.
|
Radu, S.,
Y. K. Ho,
S. Lihan,
Yuherman,
G. Rusul,
R. M. Yasin,
J. Khair, and N. Elhadi.
1999.
Molecular characterization of Vibrio cholerae O1 and non-O1 from human and environmental sources in Malaysia.
Epidemiol. Infect.
123:225-232[CrossRef][Medline].
|
| 14.
|
Russel, R. G.,
B. D. Tall, and J. G. Morris, Jr.
1992.
Non-O1 Vibrio cholerae intestinal pathology and invasion in the removable intestinal tie adult rabbit diarrhea model.
Infect. Immun.
60:435-442[Abstract/Free Full Text].
|
| 15.
|
Saha, P. K.,
H. Koley, and G. B. Nair.
1996.
Purification and characterization of an extracellular secretogenic non-membrane-damaging cytotoxin produced by clinical strains of Vibrio cholerae non-O1.
Infect. Immun.
64:3101-3108[Abstract].
|
| 16.
|
Silva, T. M. J.,
M. A. Schleupner,
C. O. Tacket,
T. S. Steiner,
J. B. Kaper,
R. Edelman, and R. L. Guerrant.
1996.
New evidence for an inflammatory component in diarrhea caused by selected new, live attenuated cholera vaccines and by El Tor and O139 Vibrio cholerae.
Infect. Immun.
64:2362-2364[Abstract].
|
| 17.
|
Welch, R. A.,
C. Forestier,
A. Lobo,
S. Pellett,
W. Thomas, Jr., and G. Rowe.
1992.
The synthesis and function of the Escherichia coli hemolysin and related RTX exotoxins.
FEMS Microbiol. Immunol.
5:29-36[CrossRef][Medline].
|
| 18.
|
Wong, S. S. Y.,
W. C. Yam,
P. M. H. Leung,
P. C. Y. Woo, and K. Y. Yuen.
1998.
Verocytotoxin-producing Escherichia coli infection: the Hong Kong Experience.
J. Gastroenterol. Hepatol.
13(Suppl.):S289-S293.
|
| 19.
|
Yam, W. C.,
C. Y. Chan,
B. S. W. Ho,
T. Y. Tam,
C. Kueh, and T. Lee.
1999.
Abundance of clinical enteric bacterial pathogens in coastal waters and shellfish.
Water Res.
34:51-56[CrossRef].
|
| 20.
|
Yam, W. C.,
D. N. C. Tsang,
T. L. Que,
M. Peiris,
W. H. Seto, and K. Y. Yuen.
1998.
Unique strain of E. coli O157:H7 excreting low level of verocytotoxin missed by commercial EIA kit.
Clin. Infect. Dis.
27:905-906[Medline].
|
| 21.
|
Yam, W. C.,
K. Y. Yuen,
S. S. Wong, and T. L. Que.
1994.
Vibrio cholerae O139 susceptible to vibriostatic agent O/129 and co-trimoxazole.
Lancet
344:404-405[CrossRef][Medline].
|
| 22.
|
Yam, W. C.,
M. L. Lung,
K. Y. Ng, and M. H. Ng.
1989.
Molecular epidemiology of Vibrio cholerae in Hong Kong.
J. Clin. Microbiol.
27:1900-1902[Abstract/Free Full Text].
|
| 23.
|
Yam, W. C.,
M. L. Lung,
K. Y. Ng, and M. H. Ng.
1991.
Restriction fragment length polymorphism analysis of Vibrio cholerae strains associated with a cholera outbreak in Hong Kong.
J. Clin. Microbiol.
29:1058-1059[Abstract/Free Full Text].
|
| 24.
|
Yam, W. C.,
M. L. Lung,
K. Y. Ng, and M. H. Ng.
1992.
Evaluation and optimization of a latex agglutination assay for the detection of cholera toxin and Escherichia coli heat-labile toxin.
J. Clin. Microbiol.
30:2518-2520[Abstract/Free Full Text].
|
| 25.
|
Yamamoto, K.,
M. Al-Omani,
T. Honda,
Y. Takeda, and T. Miwatani.
1984.
Non-O1 Vibrio cholerae hemolysin: purification, partial characterization, and immunological relatedness to El Tor hemolysin.
Infect. Immun.
45:192-196[Abstract/Free Full Text].
|
| 26.
|
Yamamoto, K.,
Y. Ichinose,
N. Nakasone,
M. Tanabe,
M. Nagahama,
J. Sakurai, and M. Iwanaga.
1986.
Identity of hemolysins produced by Vibrio cholerae non-O1 and V. cholerae O1, biotype El Tor.
Infect. Immun.
51:927-931[Abstract/Free Full Text].
|
| 27.
|
Yuen, K. Y.,
W. C. Yam, and S. S. Wong.
1994.
V. cholerae O139 synonym Bengal in Hong Kong.
Clin. Infect. Dis.
19:553-554[Medline].
|
Journal of Clinical Microbiology, July 2001, p. 2594-2597, Vol. 39, No. 7
0095-1137/01/$04.00+0 DOI: 10.1128/JCM.39.7.2594-2597.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.
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Cordero, C. L., Kudryashov, D. S., Reisler, E., Satchell, K. J. F.
(2006). The Actin Cross-linking Domain of the Vibrio cholerae RTX Toxin Directly Catalyzes the Covalent Cross-linking of Actin. J. Biol. Chem.
281: 32366-32374
[Abstract]
[Full Text]
-
Gubala, A. J., Proll, D. F.
(2006). Molecular-Beacon Multiplex Real-Time PCR Assay for Detection of Vibrio cholerae. Appl. Environ. Microbiol.
72: 6424-6428
[Abstract]
[Full Text]
-
Purdy, A., Rohwer, F., Edwards, R., Azam, F., Bartlett, D. H.
(2005). A Glimpse into the Expanded Genome Content of Vibrio cholerae through Identification of Genes Present in Environmental Strains. J. Bacteriol.
187: 2992-3001
[Abstract]
[Full Text]
-
Sheahan, K.-L., Cordero, C. L., Fullner Satchell, K. J.
(2004). Identification of a domain within the multifunctional Vibrio cholerae RTX toxin that covalently cross-links actin. Proc. Natl. Acad. Sci. USA
101: 9798-9803
[Abstract]
[Full Text]
-
Chen, C.-H., Shimada, T., Elhadi, N., Radu, S., Nishibuchi, M.
(2004). Phenotypic and Genotypic Characteristics and Epidemiological Significance of ctx+ Strains of Vibrio cholerae Isolated from Seafood in Malaysia. Appl. Environ. Microbiol.
70: 1964-1972
[Abstract]
[Full Text]
-
Faruque, S. M., Chowdhury, N., Kamruzzaman, M., Dziejman, M., Rahman, M. H., Sack, D. A., Nair, G. B., Mekalanos, J. J.
(2004). Genetic diversity and virulence potential of environmental Vibrio cholerae population in a cholera-endemic area. Proc. Natl. Acad. Sci. USA
101: 2123-2128
[Abstract]
[Full Text]
-
Fukushima, H., Tsunomori, Y., Seki, R.
(2003). Duplex Real-Time SYBR Green PCR Assays for Detection of 17 Species of Food- or Waterborne Pathogens in Stools. J. Clin. Microbiol.
41: 5134-5146
[Abstract]
[Full Text]
-
Nesper, J., Krai{beta}, A., Schild, S., Bla{beta}, J., Klose, K. E., Bockemuhl, J., Reidl, J.
(2002). Comparative and Genetic Analyses of the Putative Vibrio cholerae Lipopolysaccharide Core Oligosaccharide Biosynthesis (wav) Gene Cluster. Infect. Immun.
70: 2419-2433
[Abstract]
[Full Text]
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Abstract
Introduction
