2000 IEEE International Conference on Multimedia and Expo. ICME2000. Proceedings. Latest Advances in the Fast Changing World of Multimedia (Cat. No.00TH8532), 2000
A content based scheme to retrieve computed tomographic images (CT) of the lung is presented. It ... more A content based scheme to retrieve computed tomographic images (CT) of the lung is presented. It consists of a visual based user interface to allow the query be made by line drawing the interested (abnormal) regions; and a training scheme to classify the relationship between the images stored in database. The system will output a set of candidate images that
IEEE International Conference on Multimedia and Expo, 2001. ICME 2001., 2001
In this paper, a content-based scheme for assisting collecting similar medical image to be used f... more In this paper, a content-based scheme for assisting collecting similar medical image to be used for the tutorial of differential diagnosis is presented. The system uses visual-based user interface to allow the user to enter or query an image by selecting the region of interest (ROI) regions; and uses neural network to classify the relationship between the images stored in
The American journal of tropical medicine and hygiene, Jan 7, 2015
Epidemic cholera was reported in Haiti in 2010, with no information available on the occurrence o... more Epidemic cholera was reported in Haiti in 2010, with no information available on the occurrence or geographic distribution of toxigenic Vibrio cholerae in Haitian waters. In a series of field visits conducted in Haiti between 2011 and 2013, water and plankton samples were collected at 19 sites. Vibrio cholerae was detected using culture, polymerase chain reaction, and direct viable count methods (DFA-DVC). Cholera toxin genes were detected by polymerase chain reaction in broth enrichments of samples collected in all visits except March 2012. Toxigenic V. cholerae was isolated from river water in 2011 and 2013. Whole genome sequencing revealed that these isolates were a match to the outbreak strain. The DFA-DVC tests were positive for V. cholerae O1 in plankton samples collected from multiple sites. Results of this survey show that toxigenic V. cholerae could be recovered from surface waters in Haiti more than 2 years after the onset of the epidemic.
Applied and environmental microbiology, Jan 2, 2015
V. cholerae non-O1/non-O139 inhabits estuarine and coastal waters globally but its clinical signi... more V. cholerae non-O1/non-O139 inhabits estuarine and coastal waters globally but its clinical significance has not been sufficiently investigated, despite the fact that it has been associated with septicemia and gastroenteritis. Emergence of virulent V. cholerae non-O1/non-O139 is consistent with recognition of new pathogenic variants worldwide. Oyster, sediment, and water samples were collected during a Vibrio surveillance program carried out in 2009-2012 in the Chesapeake Bay, Maryland (USA). V. cholerae O1 was detected by direct fluorescent antibody (DFA) but not successfully cultured, whereas 395 isolates of V. cholerae non-O1/non-O139 were confirmed by multiplex PCR and serology. Only a few of the V. cholerae non-O1/non-O139 isolates were resistant to ampicillin and/or penicillin. Most were sensitive to all antibiotics tested and 77-90% carried hemolysin hlyAET, actin cross-linking repeats in toxin rtxA, haemagglutinin protease hap, and type 6 secretion system. Ca. 19 to 21% of t...
Vibrio parahaemolyticus is a leading cause of seafood-related gastroenteritis and is also an auto... more Vibrio parahaemolyticus is a leading cause of seafood-related gastroenteritis and is also an autochthonous member of marine and estuarine environments worldwide. One-hundred seventy strains of V. parahaemolyticus were isolated from water and plankton samples collected along the Georgian coast of the Black Sea during 28 months of sample collection. All isolated strains were tested for presence of tlh, trh, and tdh. A subset of strains were serotyped and tested for additional factors and markers of pandemicity. Twenty-six serotypes, five of which are clinically relevant, were identified. Although all 170 isolates were negative for tdh, trh, and the Kanagawa Phenomenon, 7 possessed the GS-PCR sequence and 27 the 850 bp sequence of V. parahaemolyticus pandemic strains. The V. parahaemolyticus population in the Black Sea was estimated to be genomically heterogeneous by rep-PCR and the serodiversity observed did not correlate with rep-PCR genomic diversity. Statistical modeling was used to predict presence of V. parahaemolyticus as a function of water temperature, with strongest concordance observed for Green Cape site samples (Percent of total variance = 70, P < 0.001). Results demonstrate a diverse population of V. parahaemolyticus in the Black Sea, some of which carry pandemic markers, with increased water temperature correlated to an increase in abundance of V. parahaemolyticus.
Recent molecular advances in microbiology have greatly improved the detection of bacterial pathog... more Recent molecular advances in microbiology have greatly improved the detection of bacterial pathogens in the environment. These improvements and a downward trend in the cost of molecular detection methods have contributed to increased frequency of detection of pathogenic microorganisms where traditional culture-based detection methods have failed. Culture methods also have been greatly improved, and the confluence of the two suites of methods provides a powerful tool for detection, isolation, and characterization of pathogens. While molecular detection provides data on the presence and type of pathogens, culturing methods allow a researcher to preserve the organism of interest for "-omics" studies, such as genomic, metabolomic, secretomic, and transcriptomic analysis, which are rapidly becoming more affordable. This has yielded a clearer understanding of the ecology and epidemiology of microorganisms that cause disease. In this unit, we present commonly accepted methods for isolation, detection, and characterization of V. cholerae, providing more extensive knowledge of the ecology and epidemiology of this organism. This unit has been fully revised and updated from the earlier version with the latest knowledge and additional information not previously included. Curr. Protoc. Microbiol. 26:6A.5.
Proceedings of the National Academy of Sciences, 2012
The millions of deaths from cholera during the past 200 y, coupled with the morbidity and mortali... more The millions of deaths from cholera during the past 200 y, coupled with the morbidity and mortality of cholera in Haiti since October 2010, are grim reminders that Vibrio cholerae, the etiologic agent of cholera, remains a scourge. We report the isolation of both V. cholerae O1 and non-O1/O139 early in the Haiti cholera epidemic from samples collected from victims in 18 towns across eight Arrondissements of Haiti. The results showed two distinct populations of V. cholerae coexisted in Haiti early in the epidemic. As non-O1/O139 V. cholerae was the sole pathogen isolated from 21% of the clinical specimens, its role in this epidemic, either alone or in concert with V. cholerae O1, cannot be dismissed. A genomic approach was used to examine similarities and differences among the Haitian V. cholerae O1 and V. cholerae non-O1/O139 strains. A total of 47 V. cholerae O1 and 29 V. cholerae non-O1/O139 isolates from patients and the environment were sequenced. Comparative genome analyses of the 76 genomes and eight reference strains of V. cholerae isolated in concurrent epidemics outside Haiti and 27 V. cholerae genomes available in the public database demonstrated substantial diversity of V. cholerae and ongoing flux within its genome.
Genomic islands (GIs) and integrative conjugative elements (ICEs) are major players in bacterial ... more Genomic islands (GIs) and integrative conjugative elements (ICEs) are major players in bacterial evolution since they encode genes involved in adaptive functions of medical or environmental importance. Here we performed the genomic analysis of ICEVchBan8, an unusual ICE found in the genome of a clinical non-toxigenic Vibrio cholerae O37 isolate. ICEVchBan8 shares most of its genetic structure with SXT/R391 ICEs. However, this ICE codes for a different integration/excision module is located at a different insertion site, and part of its genetic cargo shows homology to other pathogenicity islands of V. cholerae.
We report the autochthonous existence of Vibrio cholerae in coastal waters of Iceland, a geotherm... more We report the autochthonous existence of Vibrio cholerae in coastal waters of Iceland, a geothermally active country where cholera is absent and has never been reported. Seawater, mussel and macroalgae samples were collected close to, and distant from, sites where geothermal activity causes a significant increase in water temperature during low tides. Vibrio cholerae was detected only at geothermal-influenced sites during low-tides. None of the V. cholerae isolates encoded cholera toxin (ctxAB) and all were non-O1/non-O139 serogroups. However, all isolates encoded other virulence factors that are associated with cholera as well as extra-intestinal V. cholerae infections. The virulence factors were functional at temperatures of coastal waters of Iceland, suggesting an ecological role. It is noteworthy that V. cholerae was isolated from samples collected at sites distant from anthropogenic influence, supporting the conclusion that V. cholerae is autochthonous to the aquatic environment of Iceland.
Vibrio parahaemolyticus and Vibrio vulnificus, which are native to estuaries globally, are agents... more Vibrio parahaemolyticus and Vibrio vulnificus, which are native to estuaries globally, are agents of seafood-borne or wound infections, both potentially fatal. Like all vibrios autochthonous to coastal regions, their abundance varies with changes in environmental parameters. Sea surface temperature (SST), sea surface height (SSH), and chlorophyll have been shown to be predictors of zooplankton and thus factors linked to vibrio populations. The contribution of salinity, conductivity, turbidity, and dissolved organic carbon to the incidence and distribution of Vibrio spp. has also been reported. Here, a multicoastal, 21-month study was conducted to determine relationships between environmental parameters and V. parahaemolyticus and V. vulnificus populations in water, oysters, and sediment in three coastal areas of the United States. Because ecologically unique sites were included in the study, it was possible to analyze individual parameters over wide ranges. Molecular methods were used to detect genes for thermolabile hemolysin (tlh), thermostable direct hemolysin (tdh), and tdh-related hemolysin (trh) as indicators of V. parahaemolyticus and the hemolysin gene vvhA for V. vulnificus. SST and suspended particulate matter were found to be strong predictors of total and potentially pathogenic V. parahaemolyticus and V. vulnificus. Other predictors included chlorophyll a, salinity, and dissolved organic carbon. For the ecologically unique sites included in the study, SST was confirmed as an effective predictor of annual variation in vibrio abundance, with other parameters explaining a portion of the variation not attributable to SST.
Between November 2010, and May 2011, eleven cases of cholera, unrelated to a concurrent outbreak ... more Between November 2010, and May 2011, eleven cases of cholera, unrelated to a concurrent outbreak on the island of Hispaniola, were recorded, and the causative agent, Vibrio cholerae serogroup O75, was traced to oysters harvested from Apalachicola Bay, Florida. From the 11 diagnosed cases, eight isolates of V. cholerae were isolated and their genomes were sequenced. Genomic analysis demonstrated the presence of a suite of mobile elements previously shown to be involved in the disease process of cholera (ctxAB, VPI-1 and -2, and a VSP-II like variant) and a phylogenomic analysis showed the isolates to be sister taxa to toxigenic V. cholerae V51 serogroup O141, a clinical strain isolated 23 years earlier. Toxigenic V. cholerae O75 has been repeatedly isolated from clinical cases in the southeastern United States and toxigenic V. cholerae O141 isolates have been isolated globally from clinical cases over several decades. Comparative genomics, phenotypic analyses, and a Caenorhabditis elegans model of infection for the isolates were conducted. This analysis coupled with isolation data of V. cholerae O75 and O141 suggests these strains may represent an underappreciated clade of choleracausing strains responsible for significant disease burden globally.
2000 IEEE International Conference on Multimedia and Expo. ICME2000. Proceedings. Latest Advances in the Fast Changing World of Multimedia (Cat. No.00TH8532), 2000
A content based scheme to retrieve computed tomographic images (CT) of the lung is presented. It ... more A content based scheme to retrieve computed tomographic images (CT) of the lung is presented. It consists of a visual based user interface to allow the query be made by line drawing the interested (abnormal) regions; and a training scheme to classify the relationship between the images stored in database. The system will output a set of candidate images that
IEEE International Conference on Multimedia and Expo, 2001. ICME 2001., 2001
In this paper, a content-based scheme for assisting collecting similar medical image to be used f... more In this paper, a content-based scheme for assisting collecting similar medical image to be used for the tutorial of differential diagnosis is presented. The system uses visual-based user interface to allow the user to enter or query an image by selecting the region of interest (ROI) regions; and uses neural network to classify the relationship between the images stored in
The American journal of tropical medicine and hygiene, Jan 7, 2015
Epidemic cholera was reported in Haiti in 2010, with no information available on the occurrence o... more Epidemic cholera was reported in Haiti in 2010, with no information available on the occurrence or geographic distribution of toxigenic Vibrio cholerae in Haitian waters. In a series of field visits conducted in Haiti between 2011 and 2013, water and plankton samples were collected at 19 sites. Vibrio cholerae was detected using culture, polymerase chain reaction, and direct viable count methods (DFA-DVC). Cholera toxin genes were detected by polymerase chain reaction in broth enrichments of samples collected in all visits except March 2012. Toxigenic V. cholerae was isolated from river water in 2011 and 2013. Whole genome sequencing revealed that these isolates were a match to the outbreak strain. The DFA-DVC tests were positive for V. cholerae O1 in plankton samples collected from multiple sites. Results of this survey show that toxigenic V. cholerae could be recovered from surface waters in Haiti more than 2 years after the onset of the epidemic.
Applied and environmental microbiology, Jan 2, 2015
V. cholerae non-O1/non-O139 inhabits estuarine and coastal waters globally but its clinical signi... more V. cholerae non-O1/non-O139 inhabits estuarine and coastal waters globally but its clinical significance has not been sufficiently investigated, despite the fact that it has been associated with septicemia and gastroenteritis. Emergence of virulent V. cholerae non-O1/non-O139 is consistent with recognition of new pathogenic variants worldwide. Oyster, sediment, and water samples were collected during a Vibrio surveillance program carried out in 2009-2012 in the Chesapeake Bay, Maryland (USA). V. cholerae O1 was detected by direct fluorescent antibody (DFA) but not successfully cultured, whereas 395 isolates of V. cholerae non-O1/non-O139 were confirmed by multiplex PCR and serology. Only a few of the V. cholerae non-O1/non-O139 isolates were resistant to ampicillin and/or penicillin. Most were sensitive to all antibiotics tested and 77-90% carried hemolysin hlyAET, actin cross-linking repeats in toxin rtxA, haemagglutinin protease hap, and type 6 secretion system. Ca. 19 to 21% of t...
Vibrio parahaemolyticus is a leading cause of seafood-related gastroenteritis and is also an auto... more Vibrio parahaemolyticus is a leading cause of seafood-related gastroenteritis and is also an autochthonous member of marine and estuarine environments worldwide. One-hundred seventy strains of V. parahaemolyticus were isolated from water and plankton samples collected along the Georgian coast of the Black Sea during 28 months of sample collection. All isolated strains were tested for presence of tlh, trh, and tdh. A subset of strains were serotyped and tested for additional factors and markers of pandemicity. Twenty-six serotypes, five of which are clinically relevant, were identified. Although all 170 isolates were negative for tdh, trh, and the Kanagawa Phenomenon, 7 possessed the GS-PCR sequence and 27 the 850 bp sequence of V. parahaemolyticus pandemic strains. The V. parahaemolyticus population in the Black Sea was estimated to be genomically heterogeneous by rep-PCR and the serodiversity observed did not correlate with rep-PCR genomic diversity. Statistical modeling was used to predict presence of V. parahaemolyticus as a function of water temperature, with strongest concordance observed for Green Cape site samples (Percent of total variance = 70, P < 0.001). Results demonstrate a diverse population of V. parahaemolyticus in the Black Sea, some of which carry pandemic markers, with increased water temperature correlated to an increase in abundance of V. parahaemolyticus.
Recent molecular advances in microbiology have greatly improved the detection of bacterial pathog... more Recent molecular advances in microbiology have greatly improved the detection of bacterial pathogens in the environment. These improvements and a downward trend in the cost of molecular detection methods have contributed to increased frequency of detection of pathogenic microorganisms where traditional culture-based detection methods have failed. Culture methods also have been greatly improved, and the confluence of the two suites of methods provides a powerful tool for detection, isolation, and characterization of pathogens. While molecular detection provides data on the presence and type of pathogens, culturing methods allow a researcher to preserve the organism of interest for "-omics" studies, such as genomic, metabolomic, secretomic, and transcriptomic analysis, which are rapidly becoming more affordable. This has yielded a clearer understanding of the ecology and epidemiology of microorganisms that cause disease. In this unit, we present commonly accepted methods for isolation, detection, and characterization of V. cholerae, providing more extensive knowledge of the ecology and epidemiology of this organism. This unit has been fully revised and updated from the earlier version with the latest knowledge and additional information not previously included. Curr. Protoc. Microbiol. 26:6A.5.
Proceedings of the National Academy of Sciences, 2012
The millions of deaths from cholera during the past 200 y, coupled with the morbidity and mortali... more The millions of deaths from cholera during the past 200 y, coupled with the morbidity and mortality of cholera in Haiti since October 2010, are grim reminders that Vibrio cholerae, the etiologic agent of cholera, remains a scourge. We report the isolation of both V. cholerae O1 and non-O1/O139 early in the Haiti cholera epidemic from samples collected from victims in 18 towns across eight Arrondissements of Haiti. The results showed two distinct populations of V. cholerae coexisted in Haiti early in the epidemic. As non-O1/O139 V. cholerae was the sole pathogen isolated from 21% of the clinical specimens, its role in this epidemic, either alone or in concert with V. cholerae O1, cannot be dismissed. A genomic approach was used to examine similarities and differences among the Haitian V. cholerae O1 and V. cholerae non-O1/O139 strains. A total of 47 V. cholerae O1 and 29 V. cholerae non-O1/O139 isolates from patients and the environment were sequenced. Comparative genome analyses of the 76 genomes and eight reference strains of V. cholerae isolated in concurrent epidemics outside Haiti and 27 V. cholerae genomes available in the public database demonstrated substantial diversity of V. cholerae and ongoing flux within its genome.
Genomic islands (GIs) and integrative conjugative elements (ICEs) are major players in bacterial ... more Genomic islands (GIs) and integrative conjugative elements (ICEs) are major players in bacterial evolution since they encode genes involved in adaptive functions of medical or environmental importance. Here we performed the genomic analysis of ICEVchBan8, an unusual ICE found in the genome of a clinical non-toxigenic Vibrio cholerae O37 isolate. ICEVchBan8 shares most of its genetic structure with SXT/R391 ICEs. However, this ICE codes for a different integration/excision module is located at a different insertion site, and part of its genetic cargo shows homology to other pathogenicity islands of V. cholerae.
We report the autochthonous existence of Vibrio cholerae in coastal waters of Iceland, a geotherm... more We report the autochthonous existence of Vibrio cholerae in coastal waters of Iceland, a geothermally active country where cholera is absent and has never been reported. Seawater, mussel and macroalgae samples were collected close to, and distant from, sites where geothermal activity causes a significant increase in water temperature during low tides. Vibrio cholerae was detected only at geothermal-influenced sites during low-tides. None of the V. cholerae isolates encoded cholera toxin (ctxAB) and all were non-O1/non-O139 serogroups. However, all isolates encoded other virulence factors that are associated with cholera as well as extra-intestinal V. cholerae infections. The virulence factors were functional at temperatures of coastal waters of Iceland, suggesting an ecological role. It is noteworthy that V. cholerae was isolated from samples collected at sites distant from anthropogenic influence, supporting the conclusion that V. cholerae is autochthonous to the aquatic environment of Iceland.
Vibrio parahaemolyticus and Vibrio vulnificus, which are native to estuaries globally, are agents... more Vibrio parahaemolyticus and Vibrio vulnificus, which are native to estuaries globally, are agents of seafood-borne or wound infections, both potentially fatal. Like all vibrios autochthonous to coastal regions, their abundance varies with changes in environmental parameters. Sea surface temperature (SST), sea surface height (SSH), and chlorophyll have been shown to be predictors of zooplankton and thus factors linked to vibrio populations. The contribution of salinity, conductivity, turbidity, and dissolved organic carbon to the incidence and distribution of Vibrio spp. has also been reported. Here, a multicoastal, 21-month study was conducted to determine relationships between environmental parameters and V. parahaemolyticus and V. vulnificus populations in water, oysters, and sediment in three coastal areas of the United States. Because ecologically unique sites were included in the study, it was possible to analyze individual parameters over wide ranges. Molecular methods were used to detect genes for thermolabile hemolysin (tlh), thermostable direct hemolysin (tdh), and tdh-related hemolysin (trh) as indicators of V. parahaemolyticus and the hemolysin gene vvhA for V. vulnificus. SST and suspended particulate matter were found to be strong predictors of total and potentially pathogenic V. parahaemolyticus and V. vulnificus. Other predictors included chlorophyll a, salinity, and dissolved organic carbon. For the ecologically unique sites included in the study, SST was confirmed as an effective predictor of annual variation in vibrio abundance, with other parameters explaining a portion of the variation not attributable to SST.
Between November 2010, and May 2011, eleven cases of cholera, unrelated to a concurrent outbreak ... more Between November 2010, and May 2011, eleven cases of cholera, unrelated to a concurrent outbreak on the island of Hispaniola, were recorded, and the causative agent, Vibrio cholerae serogroup O75, was traced to oysters harvested from Apalachicola Bay, Florida. From the 11 diagnosed cases, eight isolates of V. cholerae were isolated and their genomes were sequenced. Genomic analysis demonstrated the presence of a suite of mobile elements previously shown to be involved in the disease process of cholera (ctxAB, VPI-1 and -2, and a VSP-II like variant) and a phylogenomic analysis showed the isolates to be sister taxa to toxigenic V. cholerae V51 serogroup O141, a clinical strain isolated 23 years earlier. Toxigenic V. cholerae O75 has been repeatedly isolated from clinical cases in the southeastern United States and toxigenic V. cholerae O141 isolates have been isolated globally from clinical cases over several decades. Comparative genomics, phenotypic analyses, and a Caenorhabditis elegans model of infection for the isolates were conducted. This analysis coupled with isolation data of V. cholerae O75 and O141 suggests these strains may represent an underappreciated clade of choleracausing strains responsible for significant disease burden globally.
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Papers by Arlene Chen