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Search Results: 1 - 10 of 16 matches for " Janjira Thaipadungpanit "
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Molecular detection and speciation of pathogenic Leptospira spp. in blood from patients with culture-negative leptospirosis
Siriphan Boonsilp, Janjira Thaipadungpanit, Premjit Amornchai, Vanaporn Wuthiekanun, Wirongrong Chierakul, Direk Limmathurotsakul, Nicholas P Day, Sharon J Peacock
BMC Infectious Diseases , 2011, DOI: 10.1186/1471-2334-11-338
Abstract: We evaluated our hypothesis during a prospective study of 418 consecutive patients presenting to a hospital in northeast Thailand with an acute febrile illness. Admission blood samples were taken for Leptospira culture and PCR. A single tube nested PCR that amplified a region of the rrs gene was developed and applied, amplicons sequenced and a phylogenetic tree reconstructed.39/418 (9%) patients were culture-positive for Leptospira spp., and 81/418 (19%) patients were culture-negative but rrs PCR-positive. The species associated with culture-positive leptospirosis (37 L. interrogans and 2 L. borgpetersenii) were comparable to those associated with culture-negative, PCR-positive leptospirosis (76 L. interrogans, 4 L. borgpetersenii, 1 unidentified, possibly new species).Molecular speciation failed to identify a unique bacterial subset in patients with culture-negative, PCR-positive leptospirosis. The rate of false-negative culture was high, and we speculate that antibiotic pre-treatment is the most likely explanation for this.Leptospirosis is an acute febrile illness caused by pathogenic species belonging to the genus Leptospira [1,2]. This zoonotic disease has a worldwide distribution but is most common in tropical and subtropical regions and has the greatest impact on public health in developing countries [1-4]. Disease is maintained by chronic carrier hosts that excrete the organism into the environment, and infection in man results from direct contact with infected animals or indirect contact with a contaminated environment [1-3].Leptospira are present in the blood during the first week of infective symptoms [1,2]. Culture is rarely performed in routine clinical practice since this may take several months and requires considerable expertise, which places it within the domain of specialist reference centres. Culture continues to have an important role, however, in defining the global epidemiology of infection [4]. Identification of the serovar of infecting isolate
Emergence of Community-Associated Methicillin-Resistant Staphylococcus aureus Associated with Pediatric Infection in Cambodia
Kheng Chheng, Sarah Tarquinio, Vanaporn Wuthiekanun, Lina Sin, Janjira Thaipadungpanit, Premjit Amornchai, Ngoun Chanpheaktra, Sarinna Tumapa, Hor Putchhat, Nicholas P. J. Day, Sharon J. Peacock
PLOS ONE , 2009, DOI: 10.1371/journal.pone.0006630
Abstract: Background The incidence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infection is rising in the developed world but appears to be rare in developing countries. One explanation for this difference is that resource poor countries lack the diagnostic microbiology facilities necessary to detect the presence of CA-MRSA carriage and infection. Methodology and Principal Findings We developed diagnostic microbiology capabilities at the Angkor Hospital for Children, Siem Reap, western Cambodia in January 2006 and in the same month identified a child with severe community-acquired impetigo caused by CA-MRSA. A study was undertaken to identify and describe additional cases presenting between January 2006 and December 2007. Bacterial isolates underwent molecular characterization using multilocus sequence typing, staphylococcal cassette chromosome mec (SCCmec) typing, and PCR for the presence of the genes encoding Panton-Valentine Leukocidin (PVL). Seventeen children were identified with CA-MRSA infection, of which 11 had skin and soft tissue infection and 6 had invasive disease. The majority of cases were unrelated in time or place. Molecular characterization identified two independent MRSA clones; fifteen isolates were sequence type (ST) 834, SCCmec type IV, PVL gene-negative, and two isolates were ST 121, SCCmec type V, PVL gene-positive. Conclusions This represents the first ever report of MRSA in Cambodia, spread of which would pose a significant threat to public health. The finding that cases were mostly unrelated in time or place suggests that these were sporadic infections in persons who were CA-MRSA carriers or contacts of carriers, rather than arising in the context of an outbreak.
A Dominant Clone of Leptospira interrogans Associated with an Outbreak of Human Leptospirosis in Thailand
Janjira Thaipadungpanit,Vanaporn Wuthiekanun,Wirongrong Chierakul,Lee D. Smythe,Wimol Petkanchanapong,Roongrueng Limpaiboon,Apichat Apiwatanaporn,Andrew T. Slack,Yupin Suputtamongkol,Nicholas J. White,Edward J. Feil,Nicholas P. J. Day,Sharon J. Peacock
PLOS Neglected Tropical Diseases , 2007, DOI: 10.1371/journal.pntd.0000056
Abstract: Background A sustained outbreak of leptospirosis occurred in northeast Thailand between 1999 and 2003, the basis for which was unknown. Methods and Findings A prospective study was conducted between 2000 and 2005 to identify patients with leptospirosis presenting to Udon Thani Hospital in northeast Thailand, and to isolate the causative organisms from blood. A multilocus sequence typing scheme was developed to genotype these pathogenic Leptospira. Additional typing was performed for Leptospira isolated from human cases in other Thai provinces over the same period, and from rodents captured in the northeast during 2004. Sequence types (STs) were compared with those of Leptospira drawn from a reference collection. Twelve STs were identified among 101 isolates from patients in Udon Thani. One of these (ST34) accounted for 77 (76%) of isolates. ST34 was Leptospira interrogans, serovar Autumnalis. 86% of human Leptospira isolates from Udon Thani corresponded to ST34 in 2000/2001, but this figure fell to 56% by 2005 as the outbreak waned (p = 0.01). ST34 represented 17/24 (71%) of human isolates from other Thai provinces, and 7/8 (88%) rodent isolates. By contrast, 59 STs were found among 76 reference strains, indicating a much more diverse population genetic structure; ST34 was not identified in this collection. Conclusions Development of an MLST scheme for Leptospira interrogans revealed that a single ecologically successful pathogenic clone of L. interrogans predominated in the rodent population, and was associated with a sustained outbreak of human leptospirosis in Thailand.
Comparison of Two Multilocus Sequence Based Genotyping Schemes for Leptospira Species
Ahmed Ahmed equal contributor ,Janjira Thaipadungpanit equal contributor,Siriphan Boonsilp,Vanaporn Wuthiekanun,Kishore Nalam,Brian G. Spratt,David M. Aanensen,Lee D. Smythe,Niyaz Ahmed,Edward J. Feil,Rudy A. Hartskeerl,Sharon J. Peacock
PLOS Neglected Tropical Diseases , 2011, DOI: 10.1371/journal.pntd.0001374
Abstract: Background Several sequence based genotyping schemes have been developed for Leptospira spp. The objective of this study was to genotype a collection of clinical and reference isolates using the two most commonly used schemes and compare and contrast the results. Methods and Findings A total of 48 isolates consisting of L. interrogans (n = 40) and L. kirschneri (n = 8) were typed by the 7 locus MLST scheme described by Thaipadungpanit et al., and the 6 locus genotyping scheme described by Ahmed et al., (termed 7L and 6L, respectively). Two L. interrogans isolates were not typed using 6L because of a deletion of three nucleotides in lipL32. The remaining 46 isolates were resolved into 21 sequence types (STs) by 7L, and 30 genotypes by 6L. Overall nucleotide diversity (based on concatenated sequence) was 3.6% and 2.3% for 7L and 6L, respectively. The D value (discriminatory ability) of 7L and 6L were comparable, i.e. 92.0 (95% CI 87.5–96.5) vs. 93.5 (95% CI 88.6–98.4). The dN/dS ratios calculated for each locus indicated that none were under positive selection. Neighbor joining trees were reconstructed based on the concatenated sequences for each scheme. Both trees showed two distinct groups corresponding to L. interrogans and L. kirschneri, and both identified two clones containing 10 and 7 clinical isolates, respectively. There were six instances in which 6L split single STs as defined by 7L into closely related clusters. We noted two discrepancies between the trees in which the genetic relatedness between two pairs of strains were more closely related by 7L than by 6L. Conclusions This genetic analysis indicates that the two schemes are comparable. We discuss their practical advantages and disadvantages.
Factors Predicting and Reducing Mortality in Patients with Invasive Staphylococcus aureus Disease in a Developing Country
Emma K. Nickerson, Vanaporn Wuthiekanun, Gumphol Wongsuvan, Direk Limmathurosakul, Pramot Srisamang, Weera Mahavanakul, Janjira Thaipadungpanit, Krupal R. Shah, Arkhom Arayawichanont, Premjit Amornchai, Aunchalee Thanwisai, Nicholas P. Day, Sharon J. Peacock
PLOS ONE , 2009, DOI: 10.1371/journal.pone.0006512
Abstract: Background Invasive Staphylococcus aureus infection is increasingly recognised as an important cause of serious sepsis across the developing world, with mortality rates higher than those in the developed world. The factors determining mortality in developing countries have not been identified. Methods A prospective, observational study of invasive S. aureus disease was conducted at a provincial hospital in northeast Thailand over a 1-year period. All-cause and S. aureus-attributable mortality rates were determined, and the relationship was assessed between death and patient characteristics, clinical presentations, antibiotic therapy and resistance, drainage of pus and carriage of genes encoding Panton-Valentine Leukocidin (PVL). Principal Findings A total of 270 patients with invasive S. aureus infection were recruited. The range of clinical manifestations was broad and comparable to that described in developed countries. All-cause and S. aureus-attributable mortality rates were 26% and 20%, respectively. Early antibiotic therapy and drainage of pus were associated with a survival advantage (both p<0.001) on univariate analysis. Patients infected by a PVL gene-positive isolate (122/248 tested, 49%) had a strong survival advantage compared with patients infected by a PVL gene-negative isolate (all-cause mortality 11% versus 39% respectively, p<0.001). Multiple logistic regression analysis using all variables significant on univariate analysis revealed that age, underlying cardiac disease and respiratory infection were risk factors for all-cause and S. aureus-attributable mortality, while one or more abscesses as the presenting clinical feature and procedures for infectious source control were associated with survival. Conclusions Drainage of pus and timely antibiotic therapy are key to the successful management of S. aureus infection in the developing world. Defining the presence of genes encoding PVL provides no practical bedside information and draws attention away from identifying verified clinical risk factors and those interventions that save lives.
Genomic acquisition of a capsular polysaccharide virulence cluster by non-pathogenic Burkholderia isolates
Bernice Meng Qi Sim, Narisara Chantratita, Wen Fong Ooi, Tannistha Nandi, Ryan Tewhey, Vanaporn Wuthiekanun, Janjira Thaipadungpanit, Sarinna Tumapa, Pramila Ariyaratne, Wing-Kin Sung, Xiao Hui Sem, Hui Hoon Chua, Kalpana Ramnarayanan, Chi Ho Lin, Yichun Liu, Edward J Feil, Mindy B Glass, Gladys Tan, Sharon J Peacock, Patrick Tan
Genome Biology , 2010, DOI: 10.1186/gb-2010-11-8-r89
Abstract: Of 39 genomic regions variably present across the B. thailandensis strains, 13 regions corresponded to known genomic islands, while 26 regions were novel. Variant B. thailandensis isolates exhibited isolated acquisition of a capsular polysaccharide biosynthesis gene cluster (B. pseudomallei-like capsular polysaccharide) closely resembling a similar cluster in B. pseudomallei that is essential for virulence in mammals; presence of this cluster was confirmed by whole genome sequencing of a representative variant strain (B. thailandensis E555). Both whole-genome microarray and multi-locus sequence typing analysis revealed that the variant strains formed part of a phylogenetic subgroup distinct from the ancestral B. thailandensis population and were associated with atypical isolation sources when compared to the majority of previously described B. thailandensis strains. In functional assays, B. thailandensis E555 exhibited several B. pseudomallei-like phenotypes, including colony wrinkling, resistance to human complement binding, and intracellular macrophage survival. However, in murine infection assays, B. thailandensis E555 did not exhibit enhanced virulence relative to other B. thailandensis strains, suggesting that additional factors are required to successfully colonize and infect mammals.The discovery of such novel variant strains demonstrates how unbiased genomic surveys of non-pathogenic isolates can reveal insights into the development and emergence of new pathogenic species.The evolution of pathogen virulence is a complex process involving macrogenomic processes, such as large-scale gene acquisition and loss, combined with more subtle modifications of existing genes and regulatory pathways. Previous studies have shown that microbial pathogens can employ a variety of molecular factors to enable human and animal infection, such as type III toxin secretion systems, adhesins, and modulators of host signaling pathways [1-4]. As the compendium of virulence factors i
A Single Multilocus Sequence Typing (MLST) Scheme for Seven Pathogenic Leptospira Species
Siriphan Boonsilp equal contributor,Janjira Thaipadungpanit equal contributor ,Premjit Amornchai,Vanaporn Wuthiekanun,Mark S. Bailey,Matthew T. G. Holden,Cuicai Zhang,Xiugao Jiang,Nobuo Koizumi,Kyle Taylor,Renee Galloway,Alex R. Hoffmaster,Scott Craig,Lee D. Smythe,Rudy A. Hartskeerl,Nicholas P. Day,Narisara Chantratita,Edward J. Feil,David M. Aanensen,Brian G. Spratt,Sharon J. Peacock
PLOS Neglected Tropical Diseases , 2013, DOI: 10.1371/journal.pntd.0001954
Abstract: Background The available Leptospira multilocus sequence typing (MLST) scheme supported by a MLST website is limited to L. interrogans and L. kirschneri. Our aim was to broaden the utility of this scheme to incorporate a total of seven pathogenic species. Methodology and Findings We modified the existing scheme by replacing one of the seven MLST loci (fadD was changed to caiB), as the former gene did not appear to be present in some pathogenic species. Comparison of the original and modified schemes using data for L. interrogans and L. kirschneri demonstrated that the discriminatory power of the two schemes was not significantly different. The modified scheme was used to further characterize 325 isolates (L. alexanderi [n = 5], L. borgpetersenii [n = 34], L. interrogans [n = 222], L. kirschneri [n = 29], L. noguchii [n = 9], L. santarosai [n = 10], and L. weilii [n = 16]). Phylogenetic analysis using concatenated sequences of the 7 loci demonstrated that each species corresponded to a discrete clade, and that no strains were misclassified at the species level. Comparison between genotype and serovar was possible for 254 isolates. Of the 31 sequence types (STs) represented by at least two isolates, 18 STs included isolates assigned to two or three different serovars. Conversely, 14 serovars were identified that contained between 2 to 10 different STs. New observations were made on the global phylogeography of Leptospira spp., and the utility of MLST in making associations between human disease and specific maintenance hosts was demonstrated. Conclusion The new MLST scheme, supported by an updated MLST website, allows the characterization and species assignment of isolates of the seven major pathogenic species associated with leptospirosis.
The Uthokawiphatprasit Watergate: A Man-Made Change in Pak Phanang River Basin
Pipop PRABNARONG,Janjira KAEWRAT
Walailak Journal of Science and Technology , 2006, DOI: 10.2004/vol3iss2pp131-143
Abstract: This minireview article investigates the environmental changes since the operation of the Uthokawiphatprasit watergate over the Pak Phanang River in the southern east coast of Thailand. It was revealed that the watergate caused the slow down of water circulation in the bay which accelerated the rate of sediment deposition. The watergate also resulted in poor water quality in the Pak Phanang River which caused the declination of fish species and fish production. Moreover, it resulted in a lower production of Nipa Palm which is an important economic tree in the basin. Finally, there was evidence that the watergate might cause the spread of Malaria in this area.
Growth Performance, Carcass Quality, Visceral Organs and Intestinal Histology in Broilers Fed Dietary Dried Fermented Ginger and/or Fermented Corncob Powder  [PDF]
Duddoa Khonyoung, Janjira Sittiya, Koh-en Yamauchi
Food and Nutrition Sciences (FNS) , 2017, DOI: 10.4236/fns.2017.85039
Abstract: To determine whether dried fermented ginger (DFG), fermented with Japanese mugwort silage juice, could be replaced by fermented corncob powder (FCP) as a of feed ingredient source without significant body weight decrease or damage to visceral organs (using gross anatomical observation), to intestinal villi (using light microscopy), or to the epithelial cells on the villus apical surface (using scanning electron microscopy) the following investigation was performed. Sixty-four male broilers were allotted to 4 groups: a basal diet group (control group), and basal diet groups with DFG at a level of 50 ppm; with DFG at 50 ppm and FCP at 250 ppm (50 ppm DFG + 250 ppm FCP group); and with FCP at a level of 500 ppm (500 ppm FCP group). Feed intake, body weight gain, feed efficiency, carcass quality, small intestinal length and weight, and visceral organ weight were not different among groups. Furthermore, regarding intestinal villus height, villus area and crypt depth, a significant difference was not found among the groups. When these values of the control were expressed as an index of 100, the duodenal villus height of the 50 ppm DFG + 250 ppm FCP group and the 500 ppm FCP group were 114 and 119, respectively. The duodenal villus area of the 50 ppm DFG + 250 ppm FCP group and the 500 ppm FCP group were 125 and 158, respectively. These villus heights and areas are thought to be activated. On the epithelial cells on the villus apical surface in the duodenum and jejunum, the 50 ppm DFG + 250 ppm FCP group had protuberated cells into the intestinal lumen and deeper cells at the sites of recently exfoliated cells, suggesting that these cells are activated. The present results indicate that small amounts of fermented corncob powder can be used as a feed supplement when mixed with fermented ginger powder, due to the synergy between the two ingredients, resulting in a 6% increase in body weight gain。
荧光胺电化学检测水溶液中的氨:荧光检测与伏安分析比较
Janjira Panchompoo,Richard G. Compton
电化学 , 2012,
Abstract: 荧光胺是一种非荧光剂,其易与伯胺反应形成荧光产物,被普遍用于伯胺的荧光光谱定量分析.本文利用荧光胺与伯胺反应发展了一种新型灵敏的伏安法用于检测水溶液中的伯胺.首先,在有、无伯胺的0.1molL-1PBS(pH9.0)缓冲液中,研究了玻碳电极表面荧光胺的循环伏安电化学行为.荧光胺的不可逆氧化峰出现在0.70V(vs.SCE),当加入伯胺时,在0.46V(vs.SCE)出现另一不可逆的氧化峰,为荧光胺与伯胺反应的产物.继续加入氨水,荧光胺的氧化峰变弱,反应产物的氧化峰则由于荧光胺按反应化学计量比随氨消耗增多而随之增大.上述两个阳极峰分别对应于荧光胺及其反应产物,采用方波伏安和荧光光谱技术可实现水溶液中伯胺的定量检测.在0~60μmolL-1氨浓度范围内,该反应产物方波伏安检测成线性响应.S/N=3或3σ时检测下限分别为0.71μmolL-1和3.17μmolL-1,与荧光法检测的结果相近.
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