Surang Chankhamhaengdecha - Academia.edu (original) (raw)

Papers by Surang Chankhamhaengdecha

Frontiers in Microbiology, Oct 14, 2022

Receptor-binding proteins (RBPs) are located at the viral tail and mediate the initial recognitio... more Receptor-binding proteins (RBPs) are located at the viral tail and mediate the initial recognition of phage to a specific bacterial host. Phage RBPs have coevolved with numerous types of host receptors resulting in the formation of a diverse assortment of cognate pairs of RBP-receptors that function during the phage attachment step. Although several Clostridioides difficile bacteriophages have been discovered, their RBPs are poorly described. Using homology analysis, putative prophage-tail structure (pts) genes were identified from the prophage genome of the C. difficile HN10 strain. Competition and enzyme-linked immunosorbent assays, using recombinant Pts HN10 M, demonstrated the interaction of this Pts to C. difficile cells, suggesting a role as a phage RBP. Gel filtration and cross-linking assay revealed the native form of this protein as a homotrimer. Moreover, truncated variants indicated that the C-terminal domain of Pts HN10 M was important for binding to C. difficile cells. Interaction of Pts HN10 M was also observed to the low-molecular weight subunit of surface-layer protein A (SlpA), located at the outermost surface of C. difficile cells. Altogether, our study highlights the function of Pts HN10 M as an RBP and potentially paves the way toward phage engineering and phage therapy against C. difficile infection.

F1000Research, Sep 8, 2020

Background: The microbial community residing in the animal gastrointestinal tract play a crucial ... more Background: The microbial community residing in the animal gastrointestinal tract play a crucial role in host health. Because of the high complexity of gut microbes, many microbes remain unclassified. Deciphering the role of each bacteria in health and diseases is only possible after its culture, identification, and characterization. During the culturomics study of feral chicken cecal sample, we cultured a possible novel strain SW165 T. Methods: For the possible novel strain SW165 T , phenotypic characterization was performed using colony morphology, Gram staining, growth in different temperature and pH and motility. Biochemical assays included carbon source utilization, enzymatic activity, cellular fatty acids and short chain fatty acid production. 16S rRNA sequencing and whole genome sequencing and comparison was performed for genetic analysis. Results: This strain was isolated from cecal content of feral chickens in Brookings, South Dakota, USA. Phylogenetic analyses based on 16S rRNA gene sequence revealed that the closest valid neighbor was Olsenella profusa DSM 13989 T (96.33% similarity) within the family Atopobiaceae. Cells were Gram-strain-positive and obligately anaerobic bacilli in chains. The optimum temperature and pH for the growth of the microorganism were 37-45 o C and pH 6.0-7.5 respectively. This strain produced acetic acid as the primary fermentation product. Major fatty acids were C 12:0 , C 14:0 , C 14:0 DMA and summed feature 1 (C 13:1 at 12-13 and C 14:0 aldehyde). Strain SW165 T exhibited a genome size of 2.43 Mbp with a G+C content of 67.59 mol%, which is the Open Peer Review Reviewer Status

new microbes and new infections, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

PLOS ONE, Jul 23, 2020

Thermophilic microorganisms and their enzymes have been utilized in various industrial applicatio... more Thermophilic microorganisms and their enzymes have been utilized in various industrial applications. In this work, we isolated and characterized thermophilic anaerobic bacteria with the cellulose and hemicellulose degrading activities from a tropical dry deciduous forest in northern Thailand. Out of 502 isolated thermophilic anaerobic soil bacteria, 6 isolates, identified as Thermoanaerobacterium sp., displayed an ability to utilize a wide range of oligosaccharides and lignocellulosic substrates. The isolates exhibited significant cellulase and xylanase activities at high temperature (65˚C). Among all isolates, Thermoanaerobacterium sp. strain R63 exhibited remarkable hydrolytic properties with the highest cellulase and xylanase activities at 1.15 U/mg and 6.17 U/mg, respectively. Extracellular extract of Thermoanaerobacterium sp. strain R63 was thermostable with an optimal temperature at 65˚C and could exhibit enzymatic activities on pH range 5.0-9.0. Our findings suggest promising applications of these thermoanaerobic bacteria and their potent enzymes for industrial purposes.

Frontiers in Microbiology, Sep 7, 2018

Antibiotic resistance is a major concern in Clostridium difficile, the causative agent of antibio... more Antibiotic resistance is a major concern in Clostridium difficile, the causative agent of antibiotic-associated diarrhea. Reduced susceptibility to first-and second-line agents is widespread, therefore various attempts have been made to seek alternative preventive and therapeutic strategies against this pathogen. In this work, the antimicrobial properties of asiatic acid were evaluated against C. difficile. Asiatic acid displayed substantial inhibitory effects on 19 C. difficile isolates collected from different sources with minimal inhibitory concentrations ranging from 10 to 20 µg/ml. Time kill analysis and minimal bactericidal concentration revealed potential bactericidal activity of this compound. Asiatic acid induced membrane damages and alterations in morphological ultrastructure in C. difficile, thereby causing the leakage of intracellular substances. Moreover, asiatic acid also displayed an inhibitory effect on cell motility, but did not interfere with biofilm formation and spore germination. Analysis of drug combination showed no synergistic effect between asiatic acid and vancomycin/metronidazole. Altogether, asiatic acid exhibited strong antimicrobial activity against vegetative cells and could serve as an alternative resource for tackling C. difficile.

Essays in Biochemistry, Feb 28, 2017

The incidence of Clostridium difficile infection has been elevated and becoming common in hospita... more The incidence of Clostridium difficile infection has been elevated and becoming common in hospitals worldwide. Although antibiotics usually serve as the primary treatment for bacterial infection including C. difficile infection, limitations and failures have been evident due to drug resistance. Antibiotic resistance in C. difficile has been recognized as one of the most important factors to promote the infection and increase the level of severity and the recurrence rate. Several outbreaks in many countries have been linked to the emergence of hypervirulent drug-resistant strains. This pathogen harbours various mechanisms against the actions of antibiotics. The present study highlights three main drug-resistant strategies in C. difficile including drug inactivation, target modification and efflux pump. Other mechanisms that potentially contribute to drug-resistant traits in this organism are also discussed.

bioRxiv (Cold Spring Harbor Laboratory), Jul 24, 2022

Salmonella colonization in chicken and human infections originating from Salmonellacontaminated p... more Salmonella colonization in chicken and human infections originating from Salmonellacontaminated poultry is a significant problem. Poultry has been identified as the most common food linked to enteric pathogen outbreaks in the United States. Since multi-drug resistant Salmonella often colonize chicken and cause human infections, methods to control Salmonella colonization in poultry are needed. The method we describe here could form the basis of developing gut microbiota-derived bacterial blends as a microbial ecosystem therapeutic against Salmonella.

Frontiers in Microbiology

Receptor-binding proteins (RBPs) are located at the viral tail and mediate the initial recognitio... more Receptor-binding proteins (RBPs) are located at the viral tail and mediate the initial recognition of phage to a specific bacterial host. Phage RBPs have co-evolved with numerous types of host receptors resulting in the formation of a diverse assortment of cognate pairs of RBP-receptors that function during the phage attachment step. Although several Clostridioides difficile bacteriophages have been discovered, their RBPs are poorly described. Using homology analysis, putative prophage-tail structure (pts) genes were identified from the prophage genome of the C. difficile HN10 strain. Competition and enzyme-linked immunosorbent assays, using recombinant PtsHN10M, demonstrated the interaction of this Pts to C. difficile cells, suggesting a role as a phage RBP. Gel filtration and cross-linking assay revealed the native form of this protein as a homotrimer. Moreover, truncated variants indicated that the C-terminal domain of PtsHN10M was important for binding to C. difficile cells. Int...

Microbiology Spectrum

Endolysin is a peptidoglycan hydrolase encoded in a phage genome. The enzyme is attractive due to... more Endolysin is a peptidoglycan hydrolase encoded in a phage genome. The enzyme is attractive due to its potential use as antibacterial treatment.

A complex microbial community in the gut generally prevent the colonization of enteric pathogens ... more A complex microbial community in the gut generally prevent the colonization of enteric pathogens such asSalmonella. Because of the high complexity, several species or combination of species in the gut can confer colonization resistance. To gain a better understanding of the colonization resistance againstSalmonella enterica, we isolated a library of 1,300 bacterial strains from feral chicken gut microbiota which represented a total of 51 species. Using a co-culture assay, we screened the representative species from this library and identified 30 species that inhibitedSalmonella entericaTyphimurium. To improve theSalmonellainhibition capacity, from a pool of fast-growing species, we formulated 66 bacterial blends, each of which composed of 10 species. Bacterial blends were more efficient in inhibitingSalmonellaas compared to individual species. The blend that showed maximum inhibition (Mix10) also inhibited other serotypes ofSalmonellafrequently found in poultry. Thein vivoeffect of ...

Genome assembly of a new bacterium strain SW165

Stevioside and rebaudioside A are the two major steviol glycosides found in Stevia rebaudiana lea... more Stevioside and rebaudioside A are the two major steviol glycosides found in Stevia rebaudiana leaves. These glycosides have been widely utilized as natural sugar substitutes in food and beverage industries. Unfortunately, the steviol glycosides quantification are still relied on laborious techniques and expensive analytical instruments, such as mass spectrometry and highperformance liquid chromatography. These analytical techniques are not only time-consuming but also requiring skilled technicians. Previously, an established enzymatic method was developed as a more convenient and inexpensive alternative assay to evaluate stevioside quantity in plant specimen. This study was aimed to screen and identify bacteria with enzymatic capabilities to degrade stevioside and rebaudioside A from soil. The soil samples were collected from the deciduous forests in Nan province, Thailand. A total of 108 bacterial strains were isolated, using minimal salt medium supplemented with stevia leave extra...

Lignin is the second most abundant polymer in plant residues and nature in general. However, lign... more Lignin is the second most abundant polymer in plant residues and nature in general. However, lignin recalcitrance poses a challenge to biofuel production from plant biomass. To overcome the problem, this research aims to isolate bacteria strains capable of degrading lignin. Potential ligninolytic bacteria strains were isolated from 16 different soil samples based on their ability to grow on minimal media with alkali lignin as sole carbon source at 40?C under microaerobic conditions. Furthermore, growth on model lignin compounds (guaiacol and veratryl alcohol) and dyes (aniline blue, methylene blue, and Congo red) was also used to isolate four potential ligninolytic strains. Results from 16s rDNA sequence analysis showed that the four isolates belonged to genus Burkholderia, Pseudomonas, and Klebsiella. The gene encoding laccase-like multicopper oxidase was only detected in Burkholderia. Thus, the isolates identified in this study are capable of degrading lignin and may possess genes...

SUMMARY: In this prospective cohort study, we investigated the prevalence of Clostridium difficil... more SUMMARY: In this prospective cohort study, we investigated the prevalence of Clostridium difficileassociated diarrhea (CDAD) in adult patients with nosocomial diarrhea by performing enzyme immunoassay (EIA) for detecting toxins A and B and polymerase chain reaction (PCR) for detecting the presence of the tcdB gene in stool samples. We determined the factors associated with CDAD, and the treatment outcome of CDAD from May 2010 to January 2011. A total of 175 stool samples were tested by EIA and PCR. In total, 26.9z patients tested positive for C. difficile :1 2.6z by EIA and 24.0z by PCR. The kappa coefficient and total agreement of both the tests were 0.46 and 83.2z, respectively. Onset of diarrhea after antibiotic administration for 10 days or more (OR, 2.71; 95z CI, 1.14–6.44; P ＝ 0.024) and leukocyte count A15,000 cells/mm 3 (OR, 3.12; 95z CI, 1.24–7.88; P＝ 0.016) were significantly associated with occurrence of CDAD. The non-response rate to CDAD treatment was 24.1z, and the all...

New Microbes and New Infections, 2021

An obligately anaerobic, non-motile and Gram-positive rod bacterium, strain SW219 was isolated fr... more An obligately anaerobic, non-motile and Gram-positive rod bacterium, strain SW219 was isolated from ceacum of feral chickens. Based on 16S rRNA sequence analysis, the strain SW219 exhibited 97.88% similarity to Collinsella massiliensis strain GD3 strain, the closest valid species. The genome size of SW219 was 2.58 Mbp with 64.5 mol% of G+C content. The phenotypic and genotypic analysis suggested that the strain SW219 is a new species belonging to the family Coriobacteriaceae within the Actinobacteria phylum, which the name Collinsella avium sp. nov. is proposed. The type strain of Collinsella avium is SW219 (= DSM 109235T and = CCOS 1884T).

F1000Research, 2020

Background: The microbial community residing in the animal gastrointestinal tract play a crucial ... more Background: The microbial community residing in the animal gastrointestinal tract play a crucial role in host health. Because of the high complexity of gut microbes, many microbes remain unclassified. Deciphering the role of each bacteria in health and diseases is only possible after its culture, identification, and characterization. During the culturomics study of feral chicken cecal sample, we cultured a possible novel strain SW165T. Methods: For the possible novel strain SW165T, phenotypic characterization was performed using colony morphology, Gram staining, growth in different temperature and pH and motility. Biochemical assays included carbon source utilization, enzymatic activity, cellular fatty acids and short chain fatty acid production. 16S rRNA sequencing and whole genome sequencing and comparison was performed for genetic analysis. Results: This strain was isolated from cecal content of feral chickens in Brookings, South Dakota, USA. Phylogenetic analyses based on 16S rR...

A Gram-positive, obligately anaerobic coccobacillus, with the white raised circular colony was is... more A Gram-positive, obligately anaerobic coccobacillus, with the white raised circular colony was isolated from the cecum of feral chickens in Brookings, South Dakota, USA. The 16S rRNA gene sequence analysis suggested that the closest species to strain SW178 was Ruminococcus torques ATCC 27756T (96.94% similarity) that belongs to the family Lachnospiraceae. The genome of strain SW178 is 3.18 Mbp with G+C content of 46.9 mol%. Based on the phylogenetic and phenotypic comparison, we propose that strain SW178 be assigned to the genus Ruminococcus as a novel species, for which the name Ruminococcus catenae is proposed. The type strain is SW178 (= CCOS 1886 T, =DSM 109242T).

An obligately anaerobic, non-motile, Gram-positive coccobacillus strain SW451 was isolated from p... more An obligately anaerobic, non-motile, Gram-positive coccobacillus strain SW451 was isolated from pooled cecum contents of feral chickens. Comparative analysis based on 16s rRNA sequence showed that strain SW451 had 95.24% nucleotide sequence similarity to Sellimonas intestinalis BR31T, the closest species with a valid taxonomy. The genome of SW451 is 2.67 Mbp with 45.23 mol% of G+C content. The major cellular fatty acids were C16: 0, C14: 0 and C16: 0 DMA. Based on taxonogenomic, physiological, and biochemical analysis, the strain SW451 represents a new species of the genus Sellimonas, for which the name Sellimonas caecigallum sp. nov. is proposed. The type strain of Sellimonas caecigallum is SW451 (=DSM 109473T)

Biosensors and Bioelectronics, 2019

Vibrio parahaemolyticus is one of the most important foodborne pathogens that cause various life-... more Vibrio parahaemolyticus is one of the most important foodborne pathogens that cause various life-threatening diseases in human and animals. Here, we present a rapid detection platform for V. parahaemolyticus by combining loop-mediated isothermal amplification (LAMP) and disposable electrochemical sensors based on screen-printed graphene electrodes (SPGEs). The LAMP reactions using primers targeting V. parahaemolyticus toxR gene were optimized at an isothermal temperature of 65 C, providing specific detection of V. parahaemolyticus within 45 minutes at the detection limit of 0.3 CFU per 25 grams of raw seafood. The LAMP amplicons can be effectively detected using unmodified SPGEs, redox active molecules namely Hoechst-33258 and a portable potentiostat. Therefore, the proposed system is particularly suitable as a point-of-care device for on-site detection of food borne pathogens.

Essays in biochemistry, Jan 28, 2017

The emergence of antibiotic-resistant bacteria has become a major global health concern. Rapid an... more The emergence of antibiotic-resistant bacteria has become a major global health concern. Rapid and accurate diagnostic strategies to determine the antibiotic susceptibility profile prior to antibiotic prescription and treatment are critical to control drug resistance. The standard diagnostic procedures for the detection of antibiotic-resistant bacteria, which rely mostly on phenotypic characterization, are time consuming, insensitive and often require skilled personnel, making them unsuitable for point-of-care (POC) diagnosis. Various molecular techniques have therefore been implemented to help speed up the process and increase sensitivity. Over the past decade, microfluidic technology has gained great momentum in medical diagnosis as a series of fluid handling steps in a laboratory can be simplified and miniaturized on to a small platform, allowing marked reduction of sample amount, high portability and tremendous possibility for integration with other detection technologies. These...

Frontiers in Microbiology, Oct 14, 2022

Receptor-binding proteins (RBPs) are located at the viral tail and mediate the initial recognitio... more Receptor-binding proteins (RBPs) are located at the viral tail and mediate the initial recognition of phage to a specific bacterial host. Phage RBPs have coevolved with numerous types of host receptors resulting in the formation of a diverse assortment of cognate pairs of RBP-receptors that function during the phage attachment step. Although several Clostridioides difficile bacteriophages have been discovered, their RBPs are poorly described. Using homology analysis, putative prophage-tail structure (pts) genes were identified from the prophage genome of the C. difficile HN10 strain. Competition and enzyme-linked immunosorbent assays, using recombinant Pts HN10 M, demonstrated the interaction of this Pts to C. difficile cells, suggesting a role as a phage RBP. Gel filtration and cross-linking assay revealed the native form of this protein as a homotrimer. Moreover, truncated variants indicated that the C-terminal domain of Pts HN10 M was important for binding to C. difficile cells. Interaction of Pts HN10 M was also observed to the low-molecular weight subunit of surface-layer protein A (SlpA), located at the outermost surface of C. difficile cells. Altogether, our study highlights the function of Pts HN10 M as an RBP and potentially paves the way toward phage engineering and phage therapy against C. difficile infection.

F1000Research, Sep 8, 2020

Background: The microbial community residing in the animal gastrointestinal tract play a crucial ... more Background: The microbial community residing in the animal gastrointestinal tract play a crucial role in host health. Because of the high complexity of gut microbes, many microbes remain unclassified. Deciphering the role of each bacteria in health and diseases is only possible after its culture, identification, and characterization. During the culturomics study of feral chicken cecal sample, we cultured a possible novel strain SW165 T. Methods: For the possible novel strain SW165 T , phenotypic characterization was performed using colony morphology, Gram staining, growth in different temperature and pH and motility. Biochemical assays included carbon source utilization, enzymatic activity, cellular fatty acids and short chain fatty acid production. 16S rRNA sequencing and whole genome sequencing and comparison was performed for genetic analysis. Results: This strain was isolated from cecal content of feral chickens in Brookings, South Dakota, USA. Phylogenetic analyses based on 16S rRNA gene sequence revealed that the closest valid neighbor was Olsenella profusa DSM 13989 T (96.33% similarity) within the family Atopobiaceae. Cells were Gram-strain-positive and obligately anaerobic bacilli in chains. The optimum temperature and pH for the growth of the microorganism were 37-45 o C and pH 6.0-7.5 respectively. This strain produced acetic acid as the primary fermentation product. Major fatty acids were C 12:0 , C 14:0 , C 14:0 DMA and summed feature 1 (C 13:1 at 12-13 and C 14:0 aldehyde). Strain SW165 T exhibited a genome size of 2.43 Mbp with a G+C content of 67.59 mol%, which is the Open Peer Review Reviewer Status

new microbes and new infections, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

PLOS ONE, Jul 23, 2020

Thermophilic microorganisms and their enzymes have been utilized in various industrial applicatio... more Thermophilic microorganisms and their enzymes have been utilized in various industrial applications. In this work, we isolated and characterized thermophilic anaerobic bacteria with the cellulose and hemicellulose degrading activities from a tropical dry deciduous forest in northern Thailand. Out of 502 isolated thermophilic anaerobic soil bacteria, 6 isolates, identified as Thermoanaerobacterium sp., displayed an ability to utilize a wide range of oligosaccharides and lignocellulosic substrates. The isolates exhibited significant cellulase and xylanase activities at high temperature (65˚C). Among all isolates, Thermoanaerobacterium sp. strain R63 exhibited remarkable hydrolytic properties with the highest cellulase and xylanase activities at 1.15 U/mg and 6.17 U/mg, respectively. Extracellular extract of Thermoanaerobacterium sp. strain R63 was thermostable with an optimal temperature at 65˚C and could exhibit enzymatic activities on pH range 5.0-9.0. Our findings suggest promising applications of these thermoanaerobic bacteria and their potent enzymes for industrial purposes.

Frontiers in Microbiology, Sep 7, 2018

Antibiotic resistance is a major concern in Clostridium difficile, the causative agent of antibio... more Antibiotic resistance is a major concern in Clostridium difficile, the causative agent of antibiotic-associated diarrhea. Reduced susceptibility to first-and second-line agents is widespread, therefore various attempts have been made to seek alternative preventive and therapeutic strategies against this pathogen. In this work, the antimicrobial properties of asiatic acid were evaluated against C. difficile. Asiatic acid displayed substantial inhibitory effects on 19 C. difficile isolates collected from different sources with minimal inhibitory concentrations ranging from 10 to 20 µg/ml. Time kill analysis and minimal bactericidal concentration revealed potential bactericidal activity of this compound. Asiatic acid induced membrane damages and alterations in morphological ultrastructure in C. difficile, thereby causing the leakage of intracellular substances. Moreover, asiatic acid also displayed an inhibitory effect on cell motility, but did not interfere with biofilm formation and spore germination. Analysis of drug combination showed no synergistic effect between asiatic acid and vancomycin/metronidazole. Altogether, asiatic acid exhibited strong antimicrobial activity against vegetative cells and could serve as an alternative resource for tackling C. difficile.

Essays in Biochemistry, Feb 28, 2017

The incidence of Clostridium difficile infection has been elevated and becoming common in hospita... more The incidence of Clostridium difficile infection has been elevated and becoming common in hospitals worldwide. Although antibiotics usually serve as the primary treatment for bacterial infection including C. difficile infection, limitations and failures have been evident due to drug resistance. Antibiotic resistance in C. difficile has been recognized as one of the most important factors to promote the infection and increase the level of severity and the recurrence rate. Several outbreaks in many countries have been linked to the emergence of hypervirulent drug-resistant strains. This pathogen harbours various mechanisms against the actions of antibiotics. The present study highlights three main drug-resistant strategies in C. difficile including drug inactivation, target modification and efflux pump. Other mechanisms that potentially contribute to drug-resistant traits in this organism are also discussed.

bioRxiv (Cold Spring Harbor Laboratory), Jul 24, 2022

Salmonella colonization in chicken and human infections originating from Salmonellacontaminated p... more Salmonella colonization in chicken and human infections originating from Salmonellacontaminated poultry is a significant problem. Poultry has been identified as the most common food linked to enteric pathogen outbreaks in the United States. Since multi-drug resistant Salmonella often colonize chicken and cause human infections, methods to control Salmonella colonization in poultry are needed. The method we describe here could form the basis of developing gut microbiota-derived bacterial blends as a microbial ecosystem therapeutic against Salmonella.

Frontiers in Microbiology

Receptor-binding proteins (RBPs) are located at the viral tail and mediate the initial recognitio... more Receptor-binding proteins (RBPs) are located at the viral tail and mediate the initial recognition of phage to a specific bacterial host. Phage RBPs have co-evolved with numerous types of host receptors resulting in the formation of a diverse assortment of cognate pairs of RBP-receptors that function during the phage attachment step. Although several Clostridioides difficile bacteriophages have been discovered, their RBPs are poorly described. Using homology analysis, putative prophage-tail structure (pts) genes were identified from the prophage genome of the C. difficile HN10 strain. Competition and enzyme-linked immunosorbent assays, using recombinant PtsHN10M, demonstrated the interaction of this Pts to C. difficile cells, suggesting a role as a phage RBP. Gel filtration and cross-linking assay revealed the native form of this protein as a homotrimer. Moreover, truncated variants indicated that the C-terminal domain of PtsHN10M was important for binding to C. difficile cells. Int...

Microbiology Spectrum

Endolysin is a peptidoglycan hydrolase encoded in a phage genome. The enzyme is attractive due to... more Endolysin is a peptidoglycan hydrolase encoded in a phage genome. The enzyme is attractive due to its potential use as antibacterial treatment.

A complex microbial community in the gut generally prevent the colonization of enteric pathogens ... more A complex microbial community in the gut generally prevent the colonization of enteric pathogens such asSalmonella. Because of the high complexity, several species or combination of species in the gut can confer colonization resistance. To gain a better understanding of the colonization resistance againstSalmonella enterica, we isolated a library of 1,300 bacterial strains from feral chicken gut microbiota which represented a total of 51 species. Using a co-culture assay, we screened the representative species from this library and identified 30 species that inhibitedSalmonella entericaTyphimurium. To improve theSalmonellainhibition capacity, from a pool of fast-growing species, we formulated 66 bacterial blends, each of which composed of 10 species. Bacterial blends were more efficient in inhibitingSalmonellaas compared to individual species. The blend that showed maximum inhibition (Mix10) also inhibited other serotypes ofSalmonellafrequently found in poultry. Thein vivoeffect of ...

Genome assembly of a new bacterium strain SW165

Stevioside and rebaudioside A are the two major steviol glycosides found in Stevia rebaudiana lea... more Stevioside and rebaudioside A are the two major steviol glycosides found in Stevia rebaudiana leaves. These glycosides have been widely utilized as natural sugar substitutes in food and beverage industries. Unfortunately, the steviol glycosides quantification are still relied on laborious techniques and expensive analytical instruments, such as mass spectrometry and highperformance liquid chromatography. These analytical techniques are not only time-consuming but also requiring skilled technicians. Previously, an established enzymatic method was developed as a more convenient and inexpensive alternative assay to evaluate stevioside quantity in plant specimen. This study was aimed to screen and identify bacteria with enzymatic capabilities to degrade stevioside and rebaudioside A from soil. The soil samples were collected from the deciduous forests in Nan province, Thailand. A total of 108 bacterial strains were isolated, using minimal salt medium supplemented with stevia leave extra...

Lignin is the second most abundant polymer in plant residues and nature in general. However, lign... more Lignin is the second most abundant polymer in plant residues and nature in general. However, lignin recalcitrance poses a challenge to biofuel production from plant biomass. To overcome the problem, this research aims to isolate bacteria strains capable of degrading lignin. Potential ligninolytic bacteria strains were isolated from 16 different soil samples based on their ability to grow on minimal media with alkali lignin as sole carbon source at 40?C under microaerobic conditions. Furthermore, growth on model lignin compounds (guaiacol and veratryl alcohol) and dyes (aniline blue, methylene blue, and Congo red) was also used to isolate four potential ligninolytic strains. Results from 16s rDNA sequence analysis showed that the four isolates belonged to genus Burkholderia, Pseudomonas, and Klebsiella. The gene encoding laccase-like multicopper oxidase was only detected in Burkholderia. Thus, the isolates identified in this study are capable of degrading lignin and may possess genes...

SUMMARY: In this prospective cohort study, we investigated the prevalence of Clostridium difficil... more SUMMARY: In this prospective cohort study, we investigated the prevalence of Clostridium difficileassociated diarrhea (CDAD) in adult patients with nosocomial diarrhea by performing enzyme immunoassay (EIA) for detecting toxins A and B and polymerase chain reaction (PCR) for detecting the presence of the tcdB gene in stool samples. We determined the factors associated with CDAD, and the treatment outcome of CDAD from May 2010 to January 2011. A total of 175 stool samples were tested by EIA and PCR. In total, 26.9z patients tested positive for C. difficile :1 2.6z by EIA and 24.0z by PCR. The kappa coefficient and total agreement of both the tests were 0.46 and 83.2z, respectively. Onset of diarrhea after antibiotic administration for 10 days or more (OR, 2.71; 95z CI, 1.14–6.44; P ＝ 0.024) and leukocyte count A15,000 cells/mm 3 (OR, 3.12; 95z CI, 1.24–7.88; P＝ 0.016) were significantly associated with occurrence of CDAD. The non-response rate to CDAD treatment was 24.1z, and the all...

New Microbes and New Infections, 2021

An obligately anaerobic, non-motile and Gram-positive rod bacterium, strain SW219 was isolated fr... more An obligately anaerobic, non-motile and Gram-positive rod bacterium, strain SW219 was isolated from ceacum of feral chickens. Based on 16S rRNA sequence analysis, the strain SW219 exhibited 97.88% similarity to Collinsella massiliensis strain GD3 strain, the closest valid species. The genome size of SW219 was 2.58 Mbp with 64.5 mol% of G+C content. The phenotypic and genotypic analysis suggested that the strain SW219 is a new species belonging to the family Coriobacteriaceae within the Actinobacteria phylum, which the name Collinsella avium sp. nov. is proposed. The type strain of Collinsella avium is SW219 (= DSM 109235T and = CCOS 1884T).

F1000Research, 2020

Background: The microbial community residing in the animal gastrointestinal tract play a crucial ... more Background: The microbial community residing in the animal gastrointestinal tract play a crucial role in host health. Because of the high complexity of gut microbes, many microbes remain unclassified. Deciphering the role of each bacteria in health and diseases is only possible after its culture, identification, and characterization. During the culturomics study of feral chicken cecal sample, we cultured a possible novel strain SW165T. Methods: For the possible novel strain SW165T, phenotypic characterization was performed using colony morphology, Gram staining, growth in different temperature and pH and motility. Biochemical assays included carbon source utilization, enzymatic activity, cellular fatty acids and short chain fatty acid production. 16S rRNA sequencing and whole genome sequencing and comparison was performed for genetic analysis. Results: This strain was isolated from cecal content of feral chickens in Brookings, South Dakota, USA. Phylogenetic analyses based on 16S rR...

A Gram-positive, obligately anaerobic coccobacillus, with the white raised circular colony was is... more A Gram-positive, obligately anaerobic coccobacillus, with the white raised circular colony was isolated from the cecum of feral chickens in Brookings, South Dakota, USA. The 16S rRNA gene sequence analysis suggested that the closest species to strain SW178 was Ruminococcus torques ATCC 27756T (96.94% similarity) that belongs to the family Lachnospiraceae. The genome of strain SW178 is 3.18 Mbp with G+C content of 46.9 mol%. Based on the phylogenetic and phenotypic comparison, we propose that strain SW178 be assigned to the genus Ruminococcus as a novel species, for which the name Ruminococcus catenae is proposed. The type strain is SW178 (= CCOS 1886 T, =DSM 109242T).

An obligately anaerobic, non-motile, Gram-positive coccobacillus strain SW451 was isolated from p... more An obligately anaerobic, non-motile, Gram-positive coccobacillus strain SW451 was isolated from pooled cecum contents of feral chickens. Comparative analysis based on 16s rRNA sequence showed that strain SW451 had 95.24% nucleotide sequence similarity to Sellimonas intestinalis BR31T, the closest species with a valid taxonomy. The genome of SW451 is 2.67 Mbp with 45.23 mol% of G+C content. The major cellular fatty acids were C16: 0, C14: 0 and C16: 0 DMA. Based on taxonogenomic, physiological, and biochemical analysis, the strain SW451 represents a new species of the genus Sellimonas, for which the name Sellimonas caecigallum sp. nov. is proposed. The type strain of Sellimonas caecigallum is SW451 (=DSM 109473T)

Biosensors and Bioelectronics, 2019

Vibrio parahaemolyticus is one of the most important foodborne pathogens that cause various life-... more Vibrio parahaemolyticus is one of the most important foodborne pathogens that cause various life-threatening diseases in human and animals. Here, we present a rapid detection platform for V. parahaemolyticus by combining loop-mediated isothermal amplification (LAMP) and disposable electrochemical sensors based on screen-printed graphene electrodes (SPGEs). The LAMP reactions using primers targeting V. parahaemolyticus toxR gene were optimized at an isothermal temperature of 65 C, providing specific detection of V. parahaemolyticus within 45 minutes at the detection limit of 0.3 CFU per 25 grams of raw seafood. The LAMP amplicons can be effectively detected using unmodified SPGEs, redox active molecules namely Hoechst-33258 and a portable potentiostat. Therefore, the proposed system is particularly suitable as a point-of-care device for on-site detection of food borne pathogens.

Essays in biochemistry, Jan 28, 2017

The emergence of antibiotic-resistant bacteria has become a major global health concern. Rapid an... more The emergence of antibiotic-resistant bacteria has become a major global health concern. Rapid and accurate diagnostic strategies to determine the antibiotic susceptibility profile prior to antibiotic prescription and treatment are critical to control drug resistance. The standard diagnostic procedures for the detection of antibiotic-resistant bacteria, which rely mostly on phenotypic characterization, are time consuming, insensitive and often require skilled personnel, making them unsuitable for point-of-care (POC) diagnosis. Various molecular techniques have therefore been implemented to help speed up the process and increase sensitivity. Over the past decade, microfluidic technology has gained great momentum in medical diagnosis as a series of fluid handling steps in a laboratory can be simplified and miniaturized on to a small platform, allowing marked reduction of sample amount, high portability and tremendous possibility for integration with other detection technologies. These...