MyMedR

Displaying publications 1 - 20 of 130 in total

Abstract:

Sort:

Release of prostaglandin E2 by human mononuclear cells exposed to heat-killed Salmonella typhi

Yusof WN, Nagaratnam M, Koh CL, Puthucheary S, Pang T

Microbiol. Immunol., 1993;37(8):667-70.
PMID: 8246829

Human mononuclear cells pre-labeled with [3H]arachidonic acid were shown to release metabolites following in vitro addition of heat-killed Salmonella typhi (HKST). The amount of label released was significantly higher than that seen with live S. typhi (LST). Addition of increasing amounts of HKST resulted in an increased release of metabolites. Enzyme immunoassay of the culture supernatants revealed that the bulk of the metabolite released was prostaglandin E2 (PGE2). Leukotriene B4 (LTB4) and leukotriene C4 (LTC4) were not detectable in the culture supernatants. The significance and implications of these results are discussed.

Matched MeSH terms: Salmonella typhi*
Mimotopes of heat shock proteins of Salmonella enterica serovar Typhi identified from phage-displayed peptide library

Yuen HL, Shamala D, Thong KL

J Infect Dev Ctries, 2008 Aug 30;2(4):313-23.
PMID: 19741295

BACKGROUND: Heat shock proteins (HSPs) are known to be involved in the pathogenesis of Salmonella enterica serovar Typhi (S. Typhi), the causative agent of typhoid fever. The objective of this study was to apply a phage display library to identify mimotopes of two HSPs, HSP90 and DnaK in S. Typhi.
METHODOLOGY: A 12-mer random peptide library expressed on the surface of the filamentous phage, M13, was used to select the mimotopes of two S. Typhi heat shock proteins by biopanning with monoclonal antibodies (mAbs), DnaK and HSP90. The immunogenicity of the selected peptides was determined through binding affinity with polyclonal antibodies from pooled typhoid-confirmed patients' sera and purified HSPs mAb using Western blotting and ELISA.
RESULTS: Five rounds of biopanning resulted in enrichment of phage clones expressing the binding motifs TDxSTRP and FPSHYWLYPPPT, respectively. The selected peptides showed strong immunoreactivity with patients' sera. Thus, monoclonal antibodies against HSP and patient sera can select common mimotopes from the random peptide library.
CONCLUSION: These findings may provide fundamental information for further studies on diagnostic application or vaccine design against this aetiologic agent of typhoid fever.

Matched MeSH terms: Salmonella typhi/immunology*
Fulltext Prodigiosin inhibits bacterial growth and virulence factors as a potential physiological response to interspecies competition

Yip CH, Mahalingam S, Wan KL, Nathan S

PLoS One, 2021;16(6):e0253445.
PMID: 34161391 DOI: 10.1371/journal.pone.0253445

Prodigiosin, a red linear tripyrrole pigment, has long been recognised for its antimicrobial property. However, the physiological contribution of prodigiosin to the survival of its producing hosts still remains undefined. Hence, the aim of this study was to investigate the biological role of prodigiosin from Serratia marcescens, particularly in microbial competition through its antimicrobial activity, towards the growth and secreted virulence factors of four clinical pathogenic bacteria (methicillin-resistant Staphylococcus aureus (MRSA), Enterococcus faecalis, Salmonella enterica serovar Typhimurium and Pseudomonas aeruginosa) as well as Staphylococcus aureus and Escherichia coli. Prodigiosin was first extracted from S. marcescens and its purity confirmed by absorption spectrum, high performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrophotometry (LC-MS/MS). The extracted prodigiosin was antagonistic towards all the tested bacteria. A disc-diffusion assay showed that prodigiosin is more selective towards Gram-positive bacteria and inhibited the growth of MRSA, S. aureus and E. faecalis and Gram-negative E. coli. A minimum inhibitory concentration of 10 μg/μL of prodigiosin was required to inhibit the growth of S. aureus, E. coli and E. faecalis whereas > 10 μg/μL was required to inhibit MRSA growth. We further assessed the effect of prodigiosin towards bacterial virulence factors such as haemolysin and production of protease as well as on biofilm formation. Prodigiosin did not inhibit haemolysis activity of clinically associated bacteria but was able to reduce protease activity for MRSA, E. coli and E. faecalis as well as decrease E. faecalis, Salmonella Typhimurium and E. coli biofilm formation. Results of this study show that in addition to its role in inhibiting bacterial growth, prodigiosin also inhibits the bacterial virulence factor protease production and biofilm formation, two strategies employed by bacteria in response to microbial competition. As clinical pathogens were more resistant to prodigiosin, we propose that prodigiosin is physiologically important for S. marcescens to compete against other bacteria in its natural soil and surface water environments.

Matched MeSH terms: Salmonella typhi/drug effects; Salmonella typhi/growth & development
Ultrasensitive pathogen detection with a rolling circle amplification-empowered multiplex electrochemical DNA sensor

Yeap CSY, Chaibun T, Lee SY, Zhao B, Jan Y, La-O-Vorakiat C, et al.

Chem Commun (Camb), 2021 Nov 16;57(91):12155-12158.
PMID: 34726213 DOI: 10.1039/d1cc05181d

We report a highly sensitive and selective multiplex assay by empowering an electrochemical DNA sensor with isothermal rolling circle amplification. The assay could simultaneously detect and discriminate three common entero-pathogens in a single reaction, with femtomolar sensitivity. It is useful for field- or resource-limited settings.

Matched MeSH terms: Salmonella typhi/isolation & purification*
Fulltext Typhoid fever in children--a retrospective study of 54 cases from Malaysia

Yap YF, Puthucheary SD

Singapore Med J, 1998 Jun;39(6):260-2.
PMID: 9803814

Typhoid fever, which is endemic in Malaysia, affects all age groups and it has been stated that classical features described in textbooks were absent in children. The aim of this study was to find out whether this was true in the local setting and hence a retrospective study was undertaken.

Matched MeSH terms: Salmonella typhi/isolation & purification*
Fulltext Comparative genomics of closely related Salmonella enterica serovar Typhi strains reveals genome dynamics and the acquisition of novel pathogenic elements

Yap KP, Gan HM, Teh CS, Chai LC, Thong KL

BMC Genomics, 2014;15:1007.
PMID: 25412680 DOI: 10.1186/1471-2164-15-1007

Typhoid fever is an infectious disease of global importance that is caused by Salmonella enterica subsp. enterica serovar Typhi (S. Typhi). This disease causes an estimated 200,000 deaths per year and remains a serious global health threat. S. Typhi is strictly a human pathogen, and some recovered individuals become long-term carriers who continue to shed the bacteria in their faeces, thus becoming main reservoirs of infection.

Matched MeSH terms: Salmonella typhi/classification; Salmonella typhi/genetics*; Salmonella typhi/virology
Fulltext Global MLST of Salmonella Typhi Revisited in Post-genomic Era: Genetic Conservation, Population Structure, and Comparative Genomics of Rare Sequence Types

Yap KP, Ho WS, Gan HM, Chai LC, Thong KL

Front Microbiol, 2016;7:270.
PMID: 26973639 DOI: 10.3389/fmicb.2016.00270

Typhoid fever, caused by Salmonella enterica serovar Typhi, remains an important public health burden in Southeast Asia and other endemic countries. Various genotyping methods have been applied to study the genetic variations of this human-restricted pathogen. Multilocus sequence typing (MLST) is one of the widely accepted methods, and recently, there is a growing interest in the re-application of MLST in the post-genomic era. In this study, we provide the global MLST distribution of S. Typhi utilizing both publicly available 1,826 S. Typhi genome sequences in addition to performing conventional MLST on S. Typhi strains isolated from various endemic regions spanning over a century. Our global MLST analysis confirms the predominance of two sequence types (ST1 and ST2) co-existing in the endemic regions. Interestingly, S. Typhi strains with ST8 are currently confined within the African continent. Comparative genomic analyses of ST8 and other rare STs with genomes of ST1/ST2 revealed unique mutations in important virulence genes such as flhB, sipC, and tviD that may explain the variations that differentiate between seemingly successful (widespread) and unsuccessful (poor dissemination) S. Typhi populations. Large scale whole-genome phylogeny demonstrated evidence of phylogeographical structuring and showed that ST8 may have diverged from the earlier ancestral population of ST1 and ST2, which later lost some of its fitness advantages, leading to poor worldwide dissemination. In response to the unprecedented increase in genomic data, this study demonstrates and highlights the utility of large-scale genome-based MLST as a quick and effective approach to narrow the scope of in-depth comparative genomic analysis and consequently provide new insights into the fine scale of pathogen evolution and population structure.

Matched MeSH terms: Salmonella typhi
Fulltext Salmonella Typhi genomics: envisaging the future of typhoid eradication

Yap KP, Thong KL

Trop Med Int Health, 2017 08;22(8):918-925.
PMID: 28544285 DOI: 10.1111/tmi.12899

Next-generation whole-genome sequencing has revolutionised the study of infectious diseases in recent years. The availability of genome sequences and its understanding have transformed the field of molecular microbiology, epidemiology, infection treatments and vaccine developments. We review the key findings of the publicly accessible genomes of Salmonella enterica serovar Typhi since the first complete genome to the most recent release of thousands of Salmonella Typhi genomes, which remarkably shape the genomic research of S. Typhi and other pathogens. Important new insights acquired from the genome sequencing of S. Typhi, pertaining to genomic variations, evolution, population structure, antibiotic resistance, virulence, pathogenesis, disease surveillance/investigation and disease control are discussed. As the numbers of sequenced genomes are increasing at an unprecedented rate, fine variations in the gene pool of S. Typhi are captured in high resolution, allowing deeper understanding of the pathogen's evolutionary trends and its pathogenesis, paving the way to bringing us closer to eradication of typhoid through effective vaccine/treatment development.

Matched MeSH terms: Salmonella typhi/genetics*; Salmonella typhi/pathogenicity
Fulltext Genome sequence and comparative pathogenomics analysis of a Salmonella enterica Serovar Typhi strain associated with a typhoid carrier in Malaysia

Yap KP, Gan HM, Teh CS, Baddam R, Chai LC, Kumar N, et al.

J Bacteriol, 2012 Nov;194(21):5970-1.
PMID: 23045488 DOI: 10.1128/JB.01416-12

Salmonella enterica serovar Typhi is a human pathogen that causes typhoid fever predominantly in developing countries. In this article, we describe the whole genome sequence of the S. Typhi strain CR0044 isolated from a typhoid fever carrier in Kelantan, Malaysia. These data will further enhance the understanding of its host persistence and adaptive mechanism.

Matched MeSH terms: Salmonella typhi/genetics*; Salmonella typhi/isolation & purification
Fulltext Insights from the genome sequence of a Salmonella enterica serovar Typhi strain associated with a sporadic case of typhoid fever in Malaysia

Yap KP, Teh CS, Baddam R, Chai LC, Kumar N, Avasthi TS, et al.

J Bacteriol, 2012 Sep;194(18):5124-5.
PMID: 22933756 DOI: 10.1128/JB.01062-12

Salmonella enterica serovar Typhi is the causative agent of typhoid fever, which causes nearly 21.7 million illnesses and 217,000 deaths globally. Herein, we describe the whole-genome sequence of the Salmonella Typhi strain ST0208, isolated from a sporadic case of typhoid fever in Kuala Lumpur, Malaysia. The whole-genome sequence and comparative genomics allow an in-depth understanding of the genetic diversity, and its link to pathogenicity and evolutionary dynamics, of this highly clonal pathogen that is endemic to Malaysia.

Matched MeSH terms: Salmonella typhi/genetics*; Salmonella typhi/isolation & purification
Fulltext Ciprofloxacin-resistant Salmonella enterica serotype typhi in a patient with osteomyelitis of the rib

Wilson G, Prabhu N, Easow JM, Mukhopadhyay C

Med J Malaysia, 2005 Dec;60(5):667-9.
PMID: 16515126

Salmonella osteomyelitis of the rib is a rare clinical entity. In our case, a muhidrug resistant Salmonella enterica serotype Typhi was isolated from an immuno-competent patient with osteomyclitis of the ribs, who was treated earlier with ciprotloxacin for typhoid fever. The patient was successfully treated for osteomyclitis with intravenous ceftriaxone.

Matched MeSH terms: Salmonella typhi*
Fulltext A rapid assessment of typhoid reporting system, Kelantan, Malaysia, 2001

Wan Mansor, H., Wan Mohd. Sulaili, W.S., Khalid, Y., Hamzah, A.M., Abdul Haris, M., Hani, M.H., et al.

Malaysian Journal of Public Health Medicine, 2005;5(1):27-30.
MyJurnal

A study was conducted in Kelantan, Mabysia, in the year 2001 , to assess the typhoid reporting coverage and timeliness, and to estimate the annual incidence. Cases were persons given the diagnosis of typhoid clinically, and conhrmed cases are those with positive laboratory results. In all, 174/252 (69%) cases (95% CI = 63%-75%) were reported, ofwhich 89/131 (83%) within 7 days of diagnosis. The estimated annual typhoid incidence in Kelantan is 37/ 1 00,000.

Matched MeSH terms: Salmonella typhi
Detection of antibodies against Salmonella typhi outer membrane protein (OMP) preparation in typhoid fever patients

Verdugo-Rodriguez A, Gam LH, Devi S, Koh CL, Puthucheary SD, Calva E, et al.

Asian Pac J Allergy Immunol, 1993 Jun;11(1):45-52.
PMID: 8216558

An indirect ELISA was used to detect antibodies against outer membrane protein preparations (OMPs) from Salmonella typhi. Sera from patients with a definitive diagnosis of typhoid fever (TF) gave a mean absorbance reading, at 414 nm, of 1.52 +/- 0.23 as compared to 0.30 +/- 0.11 for sera from healthy individuals. This gave a positive to negative ratio of absorbance readings of approximately 5.1. Suspected TF patients (no isolation of S. typhi), with positive and negative Widal titers had mean absorbance readings of 1.282 +/00.46 and 0.25 +/- 0.19, respectively. Sera from patients with leptospirosis, rickettsial typhus, dengue fever, and other infections gave mean absorbances of 0.20 +/- 0.08, 0.24 +/- 0.08, 0.27 +/- 0.08, and 0.31 +/- 0.16, respectively. The sensitivity, specificity, positive and negative predictive values were 100%, 94%, 80% and 100%, respectively. The antibody response detected in the definitive TF cases was predominantly IgG in nature and no cross-reactivity was seen with OMP preparations extracted from E. coli. Variable reactivity was noted with OMP preparations obtained from other Salmonella spp. Three major OMPs are presented in the antigen preparation and strong binding of positive sera was detected to all three bands.

Matched MeSH terms: Salmonella typhi/immunology*
Synthesis, spectral analysis and biological evaluation of 2-{[(morpholin-4-yl)ethyl]thio}-5-phenyl/aryl-1,3,4-oxadiazole derivatives

Ur-Rehman A, Khan SG, Naqvi SAR, Ahmad M, Akhtar N, Bokhari TH, et al.

Pak J Pharm Sci, 2021 Jan;34(1(Special)):441-446.
PMID: 34275792

A series of new derivatives of 4-(2-chloroethyl)morpholine hydrochloride (5) were efficiently synthesized. Briefly, different aromatic organic acids (1a-f) were refluxed to acquire respective esters (2a-f) using conc. H2SO4 as catalyst. The esters were subjected to nucleophillic substitution by monohydrated hydrazine to acquire hydrazides (3a-f). The hydrazides were cyclized with CS2 in the presence of KOH to yield corresponding oxadiazoles (4a-f). Finally, the derivatives, 6a-f, were prepared by reacting oxadiazoles (4a-f) with 5 using NaH as activator. Structures of all the derivatives were elucidated through 1D-NMR EI-MS and IR spectral data. All these molecules were subjected to antibacterial and hemolytic activities and showed good antibacterial and hemolytic potential relative to the reference standards.

Matched MeSH terms: Salmonella typhi/drug effects
Peptide mimotopes of complex carbohydrates in Salmonella enterica serovar typhi which react with both carbohydrate-specific monoclonal antibody and polyclonal sera from typhoid patients

Thong KL, Tang SS, Tan WS, Devi S

Microbiol. Immunol., 2007;51(11):1045-52.
PMID: 18037781

Polyclonal sera from typhoid patients and a monoclonal antibody, mAb ATVi, which recognizes the capsular polysaccharide Vi antigen (ViCPS), were used to select for peptides that mimic the ViCPS by using a phage-displayed random 12-mer peptide library. Two major common mimotopes selected from the library carried the amino acid sequences TSHHDSHGLHRV and ENHSPVNIAHKL. Enzyme-linked immunosorbent assays (ELISAs) showed that these peptides carry mimotopes to ViCPS. Phage clones that contained the 12-mer peptides were also tested against pooled/individual typhoid patients' sera and found to have 3 to 5 times higher binding compared to normal sera. By using Phage-ELISA assays, the derived synthetic peptides, TSHHDSHGLHRV and ENHSPVNIAHKL, were tested against a monoclonal antibody mAb ATVi and over 2-fold difference in binding was found between these peptides and a control unrelated peptide, CTLTTKLYC. Inhibition of the mAb's binding to ViCPS indicated that the synthetic peptides successfully competed with the capsular polysaccharide for antibody binding.

Matched MeSH terms: Salmonella typhi/isolation & purification; Salmonella typhi/chemistry*
Multidrug-resistant strains of Salmonella enterica serotype typhi are genetically homogenous and coexist with antibiotic-sensitive strains as distinct, independent clones

Thong KL, Bhutta ZA, Pang T

Int J Infect Dis, 2000;4(4):194-7.
PMID: 11231181

OBJECTIVE: The goal of this study was to report the molecular analysis of antibiotic-sensitive and multidrug-resistant (MDR) strains of Salmonella typhi, using pulsed-field gel electrophoresis (PFGE), with a particular emphasis on the coexistence of these strains in a typhoid-endemic region of Karachi, Pakistan.
METHODS: One hundred isolates of S. typhi in humans (50 MDR and 50 antibiotic-sensitive isolates) from sporadic cases of typhoid fever were analyzed by Vi-phage typing, antibiograms and PFGE.
RESULTS: The MDR S. typhi strains were resistant to ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole. Analysis by PFGE showed that 50 MDR isolates of S. typhi had a single, homogenous PFGE profile, which was distinctly different from that of 50 antibiotic-sensitive isolates obtained in the same time frame from the same area. This latter group of isolates showed much greater diversity of PFGE profiles, as has been observed in other endemic regions.
CONCLUSIONS: Multidrug-resistant and antibiotic-susceptible strains of S. typhi can coexist in endemic areas as epidemiologically independent pathogens and are not in competition for continued persistence and transmission.

Matched MeSH terms: Salmonella typhi/classification; Salmonella typhi/drug effects*; Salmonella typhi/genetics
Genome size variation among recent human isolates of Salmonella typhi

Thong KL, Puthucheary SD, Pang T

Res. Microbiol., 1997 Mar-Apr;148(3):229-35.
PMID: 9765803

We performed genome size estimation of 17 recent human isolates of Salmonella typhi from geographically diverse regions using pulsed-field gel electrophoresis (PFGE) after digestion of chromosomal DNA with restriction endonucleases XbaI (5'-TCTAGA-3'), AvrII (5'-CCTAGG-3') and SpeI (5'-ACTAGT-3'), and summation of the sizes of restriction fragments obtained. All 17 isolates had circular chromosomes, and genome sizes differed by as much as 959 kb, ranging from 3,964 to 4,923 kb (mean genome size = 4,528 kb). The data obtained confirm the usefulness of PFGE in studies of bacterial genome size and are in agreement with recent results indicating considerable genetic diversity and genomic plasticity of S. typhi. The variation in genome sizes noted may be relevant to the observed biological properties of this important human pathogen, including its virulence.

Matched MeSH terms: Salmonella typhi/genetics*; Salmonella typhi/isolation & purification
Analysis of Salmonella typhi isolates from Southeast Asia by pulsed-field gel electrophoresis

Thong KL, Puthucheary S, Yassin RM, Sudarmono P, Padmidewi M, Soewandojo E, et al.

J Clin Microbiol, 1995 Jul;33(7):1938-41.
PMID: 7665677

Pulsed-field gel electrophoresis (PFGE) revealed that multiple genetic variants of Salmonella typhi are simultaneously present in Southeast Asia and are associated with sporadic cases of typhoid fever and occasional outbreaks. Comparative analysis of PFGE patterns also suggested that considerable genetic diversity exists among S. typhi strains and that some PFGE patterns are shared between isolates obtained from Malaysia, Indonesia, and Thailand, implying movement of these strains within these regions of Southeast Asia, where they are endemic.

Matched MeSH terms: Salmonella typhi/genetics*; Salmonella typhi/isolation & purification*
Epidemiologic analysis of sporadic Salmonella typhi isolates and those from outbreaks by pulsed-field gel electrophoresis

Thong KL, Cheong YM, Puthucheary S, Koh CL, Pang T

J Clin Microbiol, 1994 May;32(5):1135-41.
PMID: 7914202

Pulsed-field gel electrophoresis (PFGE) was used to compare and analyze 158 isolates of Salmonella typhi from five well-defined outbreaks of typhoid fever in Malaysia and also isolates involved in sporadic cases of typhoid fever occurring during the same period. Digestion of chromosomal DNAs from these S. typhi isolates with the restriction endonucleases XbaI (5'-TCTAGA-3'), SpeI (5'-ACTAGT-3'), and AvrII (5'-CCTAGG-3') and then PFGE produced restriction endonuclease analysis (REA) patterns consisting of 11 to 24 DNA fragments ranging in size from 20 to 630 kbp. Analysis of the REA patterns generated by PFGE after digestion with XbaI and SpeI indicated that the S. typhi isolates obtained from sporadic cases of infection were much more heterogeneous (at least 13 different REA patterns were detected; Dice coefficient, between 0.73 and 1.0) than those obtained during outbreaks of typhoid fever. The clonal nature and the close genetic identities of isolates from outbreaks in Alor Setar, Penang, Kota Kinabalu, Johor Bahru, and Kota Bahru were suggested by the fact that only a limited number of REA patterns, which mostly differed by only a single band, were detected (one to four patterns; Dice coefficient, between 0.82 and 1.0), although a different pattern was associated with each of these outbreaks. Comparison of REA patterns with ribotyping for 18 S. typhi isolates involved in sporadic cases of infection showed a good correlation, in that 72% of the isolates were in the same group. There was no clear correlation of phage types with a specific REA pattern. We conclude that PFGE of s. typhi chromosomal DNA digested with infrequently cutting restriction endonucleases is a useful method for comparing and differentiating S. typhi isolates for epidemiological purposes.

Matched MeSH terms: Salmonella typhi/classification; Salmonella typhi/genetics; Salmonella typhi/isolation & purification*
Increasing genetic diversity of Salmonella enterica serovar typhi isolates from papua new guinea over the period from 1992 to 1999

Thong KL, Goh YL, Yasin RM, Lau MG, Passey M, Winston G, et al.

J Clin Microbiol, 2002 Nov;40(11):4156-60.
PMID: 12409390

Pulsed-field gel electrophoresis (PFGE) of XbaI-digested chromosomal DNA was performed on 133 strains of Salmonella enterica serovar Typhi obtained from Papua New Guinea, with the objective of assessing the temporal variation of these strains. Fifty-two strains that were isolated in 1992 and 1994 were of one phage type, D2, and only two predominant PFGE profiles, X1 and X2, were present. Another 81 strains isolated between 1997 and 1999 have shown divergence, with four new phage types, UVS I (n = 63), UVS (n = 5), VNS (n = 4), and D1 (n = 9), and more genetic variability as evidenced by the multiple and new PFGE XbaI profiles (21 profiles; Dice coefficient, F = 0.71 to 0.97). The two profiles X1 and X2 have remained the stable, dominant subtypes since 1992. Cluster analysis based on the unweighted pair group method using arithmetic averages algorithm identifies two main clusters (at 87% similarity), indicating that the divergence of the PFGE subtypes was probably derived from some genomic mutations of the X1 and X2 subtypes. The majority of isolates were from patients with mild and moderate typhoid fever and had various XbaI profiles. A single isolate from a patient with fatal typhoid fever had a unique X11 profile, while four of six isolates from patients with severe typhoid fever had the X1 pattern. In addition, 12 paired serovar Typhi isolates recovered from the blood and fecal swabs of individual patients exhibited similar PFGE patterns, while in another 11 individuals paired isolates exhibited different PFGE patterns. Three pairs of isolates recovered from three individuals had different phage types and PFGE patterns, indicating infection with multiple strains. The study reiterates the usefulness of PFGE in assessing the genetic diversity of S. enterica serovar Typhi for both long-term epidemiology and in vivo stability and instability within an individual patient.

Matched MeSH terms: Salmonella typhi/classification*; Salmonella typhi/genetics; Salmonella typhi/isolation & purification

Filters

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links