Correlation between trh Possession and Urease Production of Clinical Isolates of Vibrio parahaemolyticus

Suzuki, Norihiko; Ueda, Yuka; Mori, Hideto; Takegaki, Y; Miyagi, Kazufumi; Noda, Koji; Hirose, K; Hashimoto, Satoru; Oosumi, Y; Ishibashi, Masanori

doi:10.11150/kansenshogakuzasshi1970.69.757

Cited by 7 publications

(7 citation statements)

References 3 publications

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“…Molecular epidemiological studies revealed that not only strains carrying the tdh gene but strains carrying a trh gene or both genes are strongly associated with gastroenteritis (10,29). Recently, proportion of trh-bearing strains among clinical strains has been increasing and a very strong correlation exists between the presence of the trh gene and urease production, an unusual characteristic for V. parahaemolyticus (12,(24)(25)(26)(30)(31)(32). The urease-positive strains have been isolated in various parts of the world (1,2,5,9,13,23).…”

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confidence: 99%

Emergence of a unique O3:K6 clone of Vibrio parahaemolyticus in Calcutta, India, and isolation of strains from the same clonal group from Southeast Asian travelers arriving in Japan

et al. 1997

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Active surveillance of Vibrio parahaemolyticus infection among hospitalized patients in Calcutta, India, was initiated in January 1994. The incidence of cases of V. parahaemolyticus infection suddenly increased in February 1996 and has remained high since then. One hundred thirty-four strains of V. parahaemolyticus isolated from January 1994 to August 1996 were examined for serovar, the presence of the thermostable direct hemolysin gene (tdh) and tdh-related hemolysin genes (trh1 and trh2), production of urease, and antibiogram. Strains of the O3:K6 serovar appeared for the first time in February 1996. The O3:K6 serovar strains accounted for 50 to 80% of the strains isolated during the high-incidence period (February to August 1996). All of the serovar O3:K6 strains carried the tdh gene but not the trh genes and did not produce urease. All of the isolates except two were sensitive to all of the antibiotics tested. These and the results of analysis by an arbitrarily primed PCR method indicated that the O3:K6 serovar strains belong to a unique clone. When the O3:K6 serovar strains, isolated from travelers arriving in Japan from Southeast Asian countries, were compared by the arbitrarily primed PCR method, the strains isolated between 1982 and 1993 were distinct from Calcutta O3:K6 while the strains isolated in 1995 and 1996 were indistinguishable from the Calcutta O3:K6 strains. The results suggest that this unique O3:K6 clone may have become prevalent not only in Calcutta but also in Southeast Asian countries very recently. Not only the O3:K6 strains but also the non-O3:K6, tdh-bearing strains isolated in 1996 produced thermostable direct hemolysin at high levels, and thus the level of hemolysin produced does not appear to have influenced the high incidence of serovar O3:K6 strains.

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confidence: 99%

Emergence of a unique O3:K6 clone of Vibrio parahaemolyticus in Calcutta, India, and isolation of strains from the same clonal group from Southeast Asian travelers arriving in Japan

et al. 1997

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“…The KP-negative phenotype of the Ureϩ strains was pointed out in some of the reports (2,10,13). Very recent reports on examinations of clinical strains isolated in Asian countries and Brazil indicated that the ratio of Ureϩ strains among the clinical strains is gradually increasing and that a strong correlation exists between urease production and the presence of the trh gene rather than that of the tdh gene (12,24,26,(30)(31)(32). The correlation between urease production and possession of the trh gene suggests that urease production can be used as one of the virulence markers.…”

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Analysis of the thermostable direct hemolysin (tdh) gene and the tdh-related hemolysin (trh) genes in urease-positive strains of Vibrio parahaemolyticus isolated on the West Coast of the United States

et al. 1997

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Urease-positive (Ure؉) and urease-negative (Ure؊) strains of Vibrio parahaemolyticus isolated from patients on the West Coast of the United States between 1979 and 1995 were analyzed for the thermostable direct hemolysin (tdh) gene and the tdh-related hemolysin (trh) genes (trh1 and trh2). The DNA colony hybridization method with the polynucleotide probes was used to determine the distribution of the genes. Of 60 Ure؉ strains, 59 strains (98%) had the trh (either trh1 or trh2) gene and 54 strains (90%) carried the tdh gene. The absence of the trh gene or a related sequence in an exceptional Ure؉ strain was confirmed by Southern blot analyses. The stronger correlation with the trh gene than with the tdh gene was mostly attributable to strains possessing only the trh2 gene. Of 25 Ure؊ strains, 20 strains (80%) had the tdh gene but none had the trh gene. These results indicate a very strong correlation between the Ure؉ phenotype and the trh gene and are consistent with those reported for strains isolated in Asia. The Ure؉ strains carrying the trh genes were not restricted to a unique group of the strains. The O4:K12 strains carrying the trh1 gene have predominantly been isolated since 1979. However, strains of various non-O4:K12 serovars carrying either the trh1 or the trh2 gene became predominant after 1992. In addition, analysis by the arbitrarily primed PCR method revealed two subgroups within the selected Ure؉ O4:K12 strains. Hybridization tests with oligonucleotide probes demonstrated that the trh1 sequences of the West Coast strains differ to some extent from those of Asian strains. Nevertheless, a PCR method previously established to detect both the trh1 and the trh2 genes in Asian strains could detect 98% of those genes in the West Coast strains.

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“…In addition, effect of the trh gene on tdh transcription needs to be evaluated. A small portion of V. parahaemolyticus strains produce urease (1,3,7,10,12,21,23,24,37), and almost all urease-positive strains carry the trh (either trh1 or trh2) gene (8,22,24,28,31,33,34). We demonstrated that urease production influenced the transcription of neither the trh nor tdh gene (17).…”

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Rapid and Specific Detection of tdh , trh 1, and trh 2 mRNA of Vibrio parahaemolyticus by Transcription-Reverse Transcription Concerted Reaction with an Automated System

Nakaguchi

Ishizuka²,

Ohnaka³

et al. 2004

J Clin Microbiol

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Vibrio parahaemolyticus strains carrying the thermostable direct hemolysin (TDH) tdh gene, the TDH-related hemolysin (trh) gene, or both genes are considered virulent strains. We previously demonstrated that the transcription-reverse transcription concerted (TRC) method could be used to quantify the amount of mRNA transcribed from the tdh gene by using an automated detection system. In this study, we devised two TRC-based assays to quantify the mRNAs transcribed from the trh1 and trh2 genes, the two representative trh genes. The TRC-based detection assays for the tdh, trh1, and trh2 transcripts could specifically and quantitatively detect 10 3 to 10 7 copies of the corresponding calibrator RNAs. We examined by the three TRC assays the total RNA preparations extracted from 103 strains of Vibrio parahaemolyticus carrying the tdh, trh1, or trh2 gene in various combinations. The tdh, trh1, and trh2 mRNAs in the total RNA preparations were specifically quantified, and the time needed for detection ranged from 9 to 19 min, from 14 to 18 min, and from 9 to 12 min, respectively. The results showed that this automated TRC assays could detect the tdh, trh1, and trh2 mRNAs specifically, quantitatively, and rapidly. The relative levels of TDH determined by the immunological method and that of tdh mRNA determined by the TRC assays for most tdh-positive strains correlated. Interestingly, the levels of TDH produced from the strains carrying both tdh and trh genes were lower than those carrying only the tdh gene, whereas the levels of mRNA did not significantly differ between the two groups.Vibrio parahaemolyticus can cause seafood-borne gastroenteritis in humans. However, not all strains are considered virulent strains. The Kanagawa phenomenon, ␤-type hemolysis in Wagatsuma agar was formerly considered the marker of virulent strains because early studies demonstrated that most clinical strains, but few environmental strains, exhibit this phenomenon (16,29). Thermostable direct hemolysin (TDH) is responsible for the Kanagawa phenomenon. Subsequently, clinical strains lacking the ability to produce TDH but producing a TDH-related hemolysin (TRH) were discovered (5, 6). The strains carrying the tdh gene encoding TDH, the trh gene encoding TRH, or both genes are now considered to be virulent strains (19); the strains carrying these hemolysin genes are strongly associated with clinical cases (11, 30). Therefore, in investigations of the infection by V. parahaemolyticus, the V. parahaemolyticus strains isolated from clinical specimens are usually examined for the tdh and trh genes in most laboratories. The strains carrying the tdh gene, the trh gene, or both genes are then examined for the O:K serotype and, if possible, the DNA fingerprint for epidemiological investigation.Our study group reported five variants of the tdh genes, tdh1 and tdh2 from a Kanagawa phenomenon-positive strain and tdh3, tdh4, and tdh5 genes from Kanagawa phenomenon-negative strains, and these five variants of the tdh gene share Ͼ97% sequence identity (19). T...

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Correlation between trh Possession and Urease Production of Clinical Isolates of Vibrio parahaemolyticus

Cited by 7 publications

References 3 publications

Emergence of a unique O3:K6 clone of Vibrio parahaemolyticus in Calcutta, India, and isolation of strains from the same clonal group from Southeast Asian travelers arriving in Japan

Emergence of a unique O3:K6 clone of Vibrio parahaemolyticus in Calcutta, India, and isolation of strains from the same clonal group from Southeast Asian travelers arriving in Japan

Analysis of the thermostable direct hemolysin (tdh) gene and the tdh-related hemolysin (trh) genes in urease-positive strains of Vibrio parahaemolyticus isolated on the West Coast of the United States

Rapid and Specific Detection of tdh , trh 1, and trh 2 mRNA of Vibrio parahaemolyticus by Transcription-Reverse Transcription Concerted Reaction with an Automated System

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