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Prosthetic valve endocarditis caused by Campylobacter fetus: a case report and literature review. J Int Med Res 2023; 51:3000605231213264. [PMID: 37987669 PMCID: PMC10664450 DOI: 10.1177/03000605231213264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 10/23/2023] [Indexed: 11/22/2023] Open
Abstract
Campylobacter fetus is a Gram-negative bacillus typically associated with bacteremia in immunocompromised patients. Prosthetic valve endocarditis (PVE) is a serious complication of prosthetic valve surgery, with a high mortality rate if not treated promptly. We present a rare case of PVE caused by C. fetus. A man in his mid-60s presented to the Emergency Department with a fever and showed elevated C-reactive protein concentrations. He had prosthetic mitral and aortic valve replacement surgery 15 years previously. Gram-negative rods were detected in a blood culture. These rods were identified as C. fetus using matrix-assisted laser desorption ionization time-of-flight mass spectrometry and confirmed by 16S rRNA sequencing. The patient was treated with gentamicin and imipenem, and underwent valve replacement surgery. C. fetus was isolated in a left atrial appendage swab obtained during the surgery. Follow-up blood cultures were negative after treatment. However, after a cardiac arrest event, the patient's general condition deteriorated, and he died. To the best of our knowledge, this is the first case of PVE caused by C. fetus in Korea and the second fatality to date. This case highlights the importance of considering C. fetus as a potential cause of PVE, even in patients without known risk factors.
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Characterization of Potential Protein Biomarkers for Major Depressive Disorder Using Matrix-Assisted Laser Desorption Ionization/Time-of-Flight Mass Spectrometry. Molecules 2021; 26:molecules26154457. [PMID: 34361610 PMCID: PMC8348063 DOI: 10.3390/molecules26154457] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/21/2021] [Accepted: 07/22/2021] [Indexed: 12/16/2022] Open
Abstract
Matrix-assisted laser desorption ionization/time-of-flight (MALDI-TOF) mass spectrometry is a sensitive analytical tool for characterizing various biomolecules in biofluids. In this study, MALDI-TOF was used to characterize potential plasma biomarkers for distinguishing patients with major depressive disorder (MDD) from patients with schizophrenia and healthy controls. To avoid interference from albumin—the predominant protein in plasma—the plasma samples were pretreated using acid hydrolysis. The results obtained by MALDI-TOF were also validated by electrospray ionization-quadrupole time-of-flight (ESI-QTOF) mass spectrometry. The analytical results were further treated with principal component analysis (PCA), hierarchical clustering analysis (HCA), and receiver operating characteristic (ROC) curve analysis. The statistical analyses showed that MDD patients could be distinguished from schizophrenia patients and healthy controls by the lack of apolipoprotein C1 (Apo C1), which, in fact, was detected in healthy controls and schizophrenia patients. This protein is suggested to be a potential plasma biomarker for distinguishing MDD patients from healthy controls and schizophrenia patients. Since sample preparation for MALDI-TOF is very simple, high-throughput plasma apolipoprotein analysis for clinical purposes is feasible.
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Brachybacterium nesterenkovii isolated from a human blood culture-a first report. New Microbes New Infect 2020; 36:100699. [PMID: 32566231 PMCID: PMC7296184 DOI: 10.1016/j.nmni.2020.100699] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 05/09/2020] [Accepted: 05/13/2020] [Indexed: 10/27/2022] Open
Abstract
Brachybacterium is a genus of Gram-positive bacteria that rarely causes infections in humans. Here we report the case of an 8-month-old infant who presented with an acute febrile illness. During the diagnostic process, a blood culture was positive with Gram-positive cocci that were identified as Brachybacterium nesterenkovii by MALDI-TOF. As a result of the unclear clinical significance of this isolate and the continuous febrile state, a second blood culture was taken and returned B. nesterenkovii once more. To our knowledge this is the first time that B. nesterenkovii has been isolated from human blood cultures during the course of a systemic infection.
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Evaluation of Staphylococcus aureus Subtyping Module for Methicillin-Resistant Staphylococcus aureus Detection Based on Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry. Front Microbiol 2019; 10:2504. [PMID: 31736927 PMCID: PMC6834645 DOI: 10.3389/fmicb.2019.02504] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 10/17/2019] [Indexed: 12/13/2022] Open
Abstract
A recently developed S. aureus subtyping module for rapidly differentiate methicillin-resistant Staphylococcus aureus (MRSA) from methicillin-susceptible S. aureus (MSSA) had been introduced into China. The principle of this method was to identify the methicillin resistance through detection of a specific phenol soluble modulin-mec peak (PSM-mec) by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS). A total of 347 non-duplicated S. aureus strains were collected from the Second Affiliated Hospital of Zhejiang University School of Medicine during January 2014 to February 2019. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the automated subtyping module in identifying MRSA were evaluated. The specificity and PPV of this method were both 100%, and the sensitivity was 60.2%. PSM-bearing MRSA was reported with different prevalence from different parts of the world, our sample collection has the highest percentage so far. The repeatability showed that 1.7% (6/347) and 18.4% (64/347) were reported differently in the intra- and inter-batch analysis, respectively, which demonstrated that the threshold of this method could be further optimized to increase the sensitivity of MRSA detection. Overall, Bruker™ MALDI Biotyper can detect S. aureus isolates with a quite high specificity and expedite the identification of MRSA isolates without using extra reagent, labor, or time. The reduced turnaround time of MRSA identification is essential for appropriate therapeutic management and timely intervention for infection control.
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Strontium Isopropoxide: A Highly Active Catalyst for the Ring-Opening Polymerization of Lactide and Various Lactones. Macromol Rapid Commun 2019; 40:e1900306. [PMID: 31506988 DOI: 10.1002/marc.201900306] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 08/14/2019] [Indexed: 01/08/2023]
Abstract
Commercially available strontium isopropoxide represents a suitable catalyst/initiator for the ring-opening polymerization (ROP) of lactide (LA), ε-caprolactone, δ-valerolactone, δ-caprolactone, and δ-decalactone. Well-defined polyesters are accessible via the solution polymerization of lactide in toluene with a [LA]:[Sr] ratio of 100:1 at room temperature with or without the addition of dodecanol as coinitiator. Kinetic studies and detailed analysis by means of matrix-assisted laser desorption ionization mass spectrometry reveal pseudo-first-order kinetics of the ROP as well as excellent endgroup fidelity of the polylactide (PLA) with isopropyl and dodecyl α-endgroups. Both isopropanolate moieties as well as the coinitiator each initiate PLA chains, enabling the synthesis of PLA with tailored molar mass. The polymerization of ε-caprolactone and δ-valerolactone confirms the high catalyst activity, which causes quantitative monomer conversion after 1 min polymerization time but broad molar mass distributions. In contrast, the catalyst is well suited for the ROP of the less reactive δ-caprolactone and δ-decalactone. Although kinetic studies reveal initially bimodal molar mass distributions, polyesters with dispersity values Ð < 1.2 and unimodal molar mass distributions can be obtained at moderate to high monomer conversions.
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Detection of gastritis-associated pathogens by culturing of gastric juice and mucosa. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2018; 11:2214-2220. [PMID: 31938333 PMCID: PMC6958204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 01/16/2018] [Indexed: 06/10/2023]
Abstract
It is well known that Helicobacter pylori (H. pylori) is not the only indigenous bacterium in the stomach, as numerous studies have revealed that the gastric microbiota contributes to the pathogenesis of gastric disease. However, the correlation between the gastric bacterial flora and gastritis is unclear. By comparing differences in viable gastric bacteria between a gastritis group and a healthy group, we examined the potential species related to chronic gastritis. We collected juice and mucosa samples from 103 consecutive patients and identified 81 species by culturing and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). The positive rates of Streptococcus and Neisseria were markedly higher in the gastritis group than those in the normal group, suggesting that certain bacterial species may play vital roles in the development of gastritis rather than acting as transient microbes. This finding can be applied to the diagnosis and treatment of chronic gastritis as evidence supporting non-Helicobacter pylori infection-related gastritis.
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Abstract
Structural analysis of purified active membrane proteins can be performed by mass spectrometry (MS). However, no large-scale expression systems for active eukaryotic membrane proteins are available. Moreover, because membrane proteins cannot easily be digested by trypsin and ionized, they are difficult to analyze by MS. We developed a method for mass spectral analysis of eukaryotic membrane proteins combined with an overexpression system in Escherichia coli. Vesicular glutamate transporter 2 (VGLUT2/SLC17A6) with a soluble α-helical protein and histidine tag on the N- and C-terminus, respectively, was overexpressed in E. coli, solubilized with detergent, and purified by Ni-NTA affinity chromatography. Proteoliposomes containing VGLUT2 retained glutamate transport activity. For MS analysis, the detergent was removed from purified VGLUT2 by trichloroacetic acid precipitation, and VGLUT2 was then subjected to reductive alkylation and tryptic digestion. The resulting peptides were detected with 88% coverage by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) MS with or without liquid chromatography. Vesicular excitatory amino acid transporter and vesicular acetylcholine transporter were also detected with similar coverage by the same method. Thus this methodology could be used to analyze purified eukaryotic active transporters. Structural analysis with chemical modifiers by MS could have applications in functional binding analysis for drug discovery.
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Rapid detection of undesired cosmetic ingredients by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2017; 23:280-286. [PMID: 29028383 DOI: 10.1177/1469066717712462] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In recent years, cosmetic industry profits soared due to the widespread use of cosmetics, which resulted in illicit manufacturers and products of poor quality. Therefore, the rapid and accurate detection of the composition of cosmetics has become crucial. At present, numerous methods, such as gas chromatography and liquid chromatography-mass spectrometry, were available for the analysis of cosmetic ingredients. However, these methods present several limitations, such as failure to perform comprehensive and rapid analysis of the samples. Compared with other techniques, matrix-assisted laser desorption ionization time-of-flight mass spectrometry offered the advantages of wide detection range, fast speed and high accuracy. In this article, we briefly summarized how to select a suitable matrix and adjust the appropriate laser energy. We also discussed the rapid identification of undesired ingredients, focusing on antibiotics and hormones in cosmetics.
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Matrix-assisted laser desorption-ionization-time-of-flight mass spectrometry as a reliable proteomic method for characterization of Escherichia coli and Salmonella isolates. Vet World 2017; 10:1083-1093. [PMID: 29062198 PMCID: PMC5639107 DOI: 10.14202/vetworld.2017.1083-1093] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 08/10/2017] [Indexed: 11/16/2022] Open
Abstract
Aim: Identification of pathogenic clinical bacterial isolates is mainly dependent on
phenotypic and genotypic characteristics of the microorganisms. These conventional
methods are costive, time-consuming, and need special skills and training. An
alternative, mass spectral (proteomics) analysis method for identification of
clinical bacterial isolates has been recognized as a rapid, reliable, and
economical method for identification. This study was aimed to evaluate and compare
the performance, sensitivity and reliability of traditional bacteriology,
phenotypic methods and matrix-assisted laser desorption-ionization-time-of-flight
mass spectrometry (MALDI-TOF MS) in the identification of clinical
Escherichia coli and Salmonella isolates
recovered from chickens. Materials and Methods: A total of 110 samples (cloacal, liver, spleen, and/or gall bladder) were
collected from apparently healthy and diseased chickens showing clinical signs as
white chalky diarrhea, pasty vent, and decrease egg production as well as freshly
dead chickens which showing postmortem lesions as enlarged liver with congestion
and enlarged gall bladder from different poultry farms. Results: Depending on colonial characteristics and morphological characteristics,
E. coli and Salmonella isolates were
recovered and detected in only 42 and 35 samples, respectively. Biochemical
identification using API 20E identification system revealed that the suspected
E. coli isolates were 33 out of 42 of colonial and
morphological identified E. coli isolates where
Salmonella isolates were represented by 26 out of 35 of
colonial and morphological identified Salmonella isolates.
Serological identification of isolates revealed that the most predominant
E. coli serotypes were O1 and O78 while the most predominant
Salmonella serotype of Salmonella was
Salmonella Pullorum. All E. coli and
Salmonella isolates were examined using MALDI-TOF MS. In
agreement with traditional identification, MADI-TOF MS identified all clinical
bacterial samples with valid scores as E. coli and
Salmonella isolates except two E. coli
isolates recovered from apparently healthy and diseased birds, respectively, with
recovery rate of 93.9% and 2 Salmonella isolates recovered
from apparently healthy and dead birds, respectively, with recovery rate of
92.3%. Conclusion: Our study demonstrated that Bruker MALDI-TOF MS Biotyper is a reliable rapid and
economic tool for the identification of Gram-negative bacteria especially
E. coli and Salmonella which could be used as
an alternative diagnostic tool for routine identification and differentiation of
clinical isolates in the bacteriological laboratory. MALDI-TOF MS need more
validation and verification and more study on the performance of direct colony and
extraction methods to detect the most sensitive one and also need using more
samples to detect sensitivity, reliability, and performance of this type of
bacterial identification.
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Development of a new protocol for rapid bacterial identification and susceptibility testing directly from urine samples. Clin Microbiol Infect 2016; 22:561.e1-6. [PMID: 26899829 DOI: 10.1016/j.cmi.2016.01.025] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 11/23/2015] [Accepted: 01/28/2016] [Indexed: 01/21/2023]
Abstract
The current gold standard method for the diagnosis of urinary tract infections (UTI) is urine culture that requires 18-48 h for the identification of the causative microorganisms and an additional 24 h until the results of antimicrobial susceptibility testing (AST) are available. The aim of this study was to shorten the time of urine sample processing by a combination of flow cytometry for screening and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) for bacterial identification followed by AST directly from urine. The study was divided into two parts. During the first part, 675 urine samples were processed by a flow cytometry device and a cut-off value of bacterial count was determined to select samples for direct identification by MALDI-TOF-MS at ≥5 × 10(6) bacteria/mL. During the second part, 163 of 1029 processed samples reached the cut-off value. The sample preparation protocol for direct identification included two centrifugation and two washing steps. Direct AST was performed by the disc diffusion method if a reliable direct identification was obtained. Direct MALDI-TOF-MS identification was performed in 140 urine samples; 125 of the samples were positive by urine culture, 12 were contaminated and 3 were negative. Reliable direct identification was obtained in 108 (86.4%) of the 125 positive samples. AST was performed in 102 identified samples, and the results were fully concordant with the routine method among 83 monomicrobial infections. In conclusion, the turnaround time of the protocol described to diagnose UTI was about 1 h for microbial identification and 18-24 h for AST.
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Discovery and verification of urinary peptides in type 2 diabetes mellitus with kidney injury. Exp Biol Med (Maywood) 2016; 241:1186-94. [PMID: 26846977 DOI: 10.1177/1535370216629007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 12/15/2015] [Indexed: 12/11/2022] Open
Abstract
Varying degrees of renal injury could lead to different changes in urinary protein composition. We want to find urinary candidate peptide biomarkers in type 2 diabetic patients with different extents of kidney injury. Two sets of patients were recruited. Discovery set: weak cationic-exchange magnetic beads coupled with matrix-assisted laser desorption ionization time-of-flight mass spectrometry were used to profile the low-molecular weight peptidome in urine samples from type 2 diabetes patients with normoalbuminura and microalbuminuria. The differently expressed urinary peptides were screened by ClinProTools2.1 bioinformatics software and identified through nano-liquid chromatography-tandem mass spectrometry. Verification set: the above screened urinary peptides were validated by use matrix-assisted laser desorption ionization time-of-flight mass spectrometry on another group of type 2 diabetes patients with different extents use of kidney injury. In the screening and identification stages, seven urinary peptides were selected as the most promising biomarker candidates, and they were identified as fragments of vitronectin precursor, isoform 1 of fibrinogen alpha chain precursor, prothrombin precursor and inter-alpha-trypsin inhibitor heavy chain H4. The diagnostic efficacy of these urinary peptides was evaluated by area under the receiver operating characteristic curve, and they were 0.767, 0.768, 0.868, 0.910, 0.860, 0.843, and 0.865, respectively. In the verification stage, m/z 1743.9, 2154, 2175.5, and 2184.9 were decreased as albumin-to-creatinine (Alb/Cre) increased and m/z 2231.1, 2430.8, and 2756.1 were elevated as Alb/Cre rose. These small molecule peptides are related to type 2 diabetes kidney damage, and they may play an important role in monitoring type 2 diabetes.
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Evidence of genotypic diversity among Candida auris isolates by multilocus sequence typing, matrix-assisted laser desorption ionization time-of-flight mass spectrometry and amplified fragment length polymorphism. Clin Microbiol Infect 2015; 22:277.e1-9. [PMID: 26548511 DOI: 10.1016/j.cmi.2015.10.022] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 10/23/2015] [Accepted: 10/27/2015] [Indexed: 02/03/2023]
Abstract
Candida auris is a multidrug-resistant nosocomial bloodstream pathogen that has been reported from Asian countries and South Africa. Herein, we studied the population structure and genetic relatedness among 104 global C. auris isolates from India, South Africa and Brazil using multilocus sequence typing (MLST), amplified fragment length polymorphism (AFLP) fingerprinting and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). RPB1, RPB2 and internal transcribed spacer (ITS) and D1/D2 regions of the ribosomal DNA were sequenced for MLST. Further, genetic variation and proteomic assessment was carried out using AFLP and MALDI-TOF MS, respectively. Both MLST and AFLP typing clearly demarcated two major clusters comprising Indian and Brazilian isolates. However, the South African isolates were randomly distributed, suggesting different genotypes. MALDI-TOF MS spectral profiling also revealed evidence of geographical clustering but did not correlate fully with the genotyping methods. Notably, overall the population structure of C. auris showed evidence of geographical clustering by all the three techniques analysed. Antifungal susceptibility testing by the CLSI microbroth dilution method revealed that fluconazole had limited activity against 87% of isolates (MIC90, 64 mg/L). Also, MIC90 of AMB was 4 mg/L. Candida auris is emerging as an important yeast pathogen globally and requires reproducible laboratory methods for identification and typing. Evaluation of MALDI-TOF MS as a typing method for this yeast is warranted.
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Automated categorization of methicillin-resistant Staphylococcus aureus clinical isolates into different clonal complexes by MALDI-TOF mass spectrometry. Clin Microbiol Infect 2015; 22:161.e1-161.e7. [PMID: 26482268 DOI: 10.1016/j.cmi.2015.10.009] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 09/28/2015] [Accepted: 10/05/2015] [Indexed: 11/28/2022]
Abstract
Early identification of methicillin-resistant Staphylococcus aureus (MRSA) dominant clones involved in infection and initiation of adequate infection control measures are essential to limit MRSA spread and understand MRSA population dynamics. In this study we evaluated the use of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF/MS) for the automated discrimination of the major MRSA lineages (clonal complexes, CC) identified in our hospital during a 20-year period (1990-2009). A collection of 82 well-characterized MRSA isolates belonging to the four main CCs (CC5, CC8, CC22 and CC398) was split into a reference set (n = 36) and a validation set (n = 46) to generate pattern recognition models using the ClinProTools software for the identification of MALDI-TOF/MS biomarker peaks. The supervised neural network (SNN) model showed the best performance compared with two other models, with sensitivity and specificity values of 100% and 99.11%, respectively. Eleven peaks (m/z range: 3278-6592) with the highest separation power were identified and used to differentiate all four CCs. Validation of the SNN model using ClinProTools resulted in a positive predictive value (PPV) of 99.6%. The specific contribution of each peak to the model was used to generate subtyping reference signatures for automated subtyping using the BioTyper software, which successfully classified MRSA isolates into their corresponding CCs with a PPV of 98.9%. In conclusion, we find this novel automated MALDI-TOF/MS approach to be a promising, powerful and reliable tool for S. aureus typing.
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Polymorphisms in checkpoint kinase 2 may contribute to lymph node metastasis from esophageal cancer. Int J Clin Exp Med 2015; 8:13883-13886. [PMID: 26550343 PMCID: PMC4613028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2015] [Accepted: 08/06/2015] [Indexed: 06/05/2023]
Abstract
Esophageal cancer, which is commonly accompanied by lymph node metastasis, is among the deadliest of cancers and carries a grim prognosis. We investigated the association between genetic variation in checkpoint kinase 2 (CHEK2), which has been linked to metastasis in other cancers, and the risk of developing lymph node metastasis from esophageal cancer. CHEK2-122 G/C genotypes were determined by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) in 296 subjects with esophageal cancer (67 cases with and 229 cases without lymph node metastasis). The associations between CHEK2 genotypes and the risk of lymph node metastasis from esophageal cancer were estimated by computing odds ratios (OR) and their 95% confidence intervals (CI). The CHEK2 GG, GC, and CC genotype frequencies in patients with and without lymph node metastasis were 47.8%, 40.3%, and 11.9% and 31.0%, 50.7%, and 18.3% respectively, and were statistically significant (χ(2) =6.591, P=0.037). Logistic regression analyses revealed that the CHEK2-122 GC genotype significantly reduced the risk of lymph node metastasis (adjusted OR=0.54, 95% CI=0.29-0.93, P=0.028) compared to the GG genotype. Subsequently, we propose that the CHEK2-122 G/C polymorphism may play a protective role in preventing lymph node metastasis from esophageal cancer, and may also provide insight toward determining patient prognosis without the use of surgery.
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Delta-toxin production deficiency in Staphylococcus aureus: a diagnostic marker of bone and joint infection chronicity linked with osteoblast invasion and biofilm formation. Clin Microbiol Infect 2015; 21:568.e1-11. [PMID: 25677632 DOI: 10.1016/j.cmi.2015.01.026] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2014] [Revised: 01/21/2015] [Accepted: 01/24/2015] [Indexed: 11/29/2022]
Abstract
Biofilm formation, intra-osteoblastic persistence, small-colony variants (SCVs) and the dysregulation of agr, the major virulence regulon, are possibly involved in staphylococcal bone and joint infection (BJI) pathogenesis. We aimed to investigate the contributions of these mechanisms among a collection of 95 Staphylococcus aureus clinical isolates from 64 acute (67.4%) and 31 chronic (32.6%) first episodes of BJI. The included isolates were compared for internalization rate, cell damage and SCV intracellular emergence using an ex vivo model of human osteoblast infection. Biofilm formation was assessed in a microbead immobilization assay (BioFilm Ring test). Virulence gene profiles were assessed by DNA microarray. Seventeen different clonal complexes were identified among the screened collection. The staphylococcal internalization rate in osteoblasts was significantly higher for chronic than acute BJI isolates, regardless of the genetic background. Conversely, no differences regarding cytotoxicity, SCV emergence, biofilm formation and virulence gene distribution were observed. Additionally, agr dysfunction, detected by the lack of delta-toxin production using whole-cell matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) analysis (n = 15; 15.8%), was significantly associated with BJI chronicity, osteoblast invasion and biofilm formation. These findings provide new insights into MSSA BJI pathogenesis, suggesting the correlation between chronicity and staphylococcal osteoblast invasion. This adaptive mechanism, along with biofilm formation, is associated with agr dysfunction, which can be routinely assessed by delta-toxin detection using MALDI-TOF spectrum analysis, possibly providing clinicians with a diagnostic marker of BJI chronicity at the time of diagnosis.
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Matrix-assisted laser desorption ionization time-of-flight mass spectrometry for the rapid identification of yeasts causing bloodstream infections. Clin Microbiol Infect 2014; 21:372-8. [PMID: 25658527 DOI: 10.1016/j.cmi.2014.11.009] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 11/07/2014] [Accepted: 11/11/2014] [Indexed: 11/28/2022]
Abstract
Few studies have systematically standardised and evaluated matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) for identification of yeasts from bloodstream infections. This is rapidly becoming pertinent for early identification of yeasts and appropriate antifungal therapy. We used 354 yeast strains identified by polymerase chain reaction (PCR) sequencing for standardisation and 367 blind clinical strains for validation of our MALDI-TOF MS protocols. We also evaluated different sample preparation methods and found the on-plate formic acid extraction method as most cost- and time-efficient. The MALDI-TOF assay correctly identified 98.9% of PCR-sequenced yeasts. Novel main spectrum projections (MSP) were developed for Candida auris, C. viswanathii and Kodamaea ohmeri, which were missing from the Bruker MALDI-TOF MS database. Spectral cut-offs computed by receiver operating characteristics (ROC) analysis showed 99.4% to 100% accuracy at a log score of ≥ 1.70 for C. tropicalis, C. parapsilosis, C. pelliculosa, C. orthopsilosis, C. albicans, C. rugosa, C. guilliermondii, C. lipolytica, C. metapsilosis, C. nivariensis. The differences in the species-specific scores of our standardisation and blind validation strains were not statistically significant, implying the optimal performance of our test protocol. The MSPs of the three new species also were validated. We conclude that MALDI-TOF MS is a rapid, accurate and reliable tool for identification of bloodstream yeasts. With proper standardisation, validation and regular database expansion, its efficiency can be further enhanced.
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Identification of urinary biomarkers for type 2 diabetes using bead-based proteomic approach. Diabetes Res Clin Pract 2013; 101:187-93. [PMID: 23769013 DOI: 10.1016/j.diabres.2013.05.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 04/23/2013] [Accepted: 05/17/2013] [Indexed: 02/05/2023]
Abstract
AIMS To seek urinary peptides as biomarkers distinguishing type 2 diabetes mellitus (T2DM) patients from healthy controls. METHODS Random urine samples obtained from 28 patients with T2DM and 29 healthy individuals were analyzed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) after purification using weak cationic-exchange magnetic beads (MB-WCX). Then the generated mass spectra of peptides were analyzed by ClinProTools2.1 bioinformatics software. Subsequently, the amino acid sequences of differently expressed peptides were identified by a nano-liquid chromatography-tandem mass spectrometry and a Sequest search found the corresponding protein name. RESULTS Three differently expressed peptides and their mass to charge ratios (m/z) were found. Compared with healthy controls, the peak areas of the three differently expressed peptides were all reduced in T2DM, and the m/z were 1056.1 (m/z), 1963.5 (m/z), 2123.5 (m/z), respectively. The above-mentioned peptides were further identified as fragments of histidine triad nucleotide-binding protein 1 (HINT1), bifunctional aminoacyl-tRNA synthetase (EPRS), and clusterin precursor protein (CLU). CONCLUSIONS Histidine triad nucleotide-binding protein 1, bifunctional aminoacyl-tRNA synthetase, and clusterin precursor protein may serve as potential biomarkers distinguishing type 2 diabetes mellitus patients from healthy controls.
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Proteomics-based identification of novel proteins in temporal tendons of patients with masticatory muscle tendon--aponeurosis hyperplasia. Int J Oral Maxillofac Surg 2013; 43:113-9. [PMID: 23870541 DOI: 10.1016/j.ijom.2013.06.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Revised: 06/02/2013] [Accepted: 06/06/2013] [Indexed: 11/26/2022]
Abstract
Masticatory muscle tendon-aponeurosis hyperplasia (MMTAH) is a new disease associated with limited mouth opening that is often misdiagnosed as a temporomandibular disorder; subsequently, patients are mistakenly treated with irreversible operations. Due to the poor presentation and characterization of symptoms, the underlying pathological conditions remain unclear. We have previously conducted a proteomic analysis of tendons derived from one MMTAH subject and one facial deformity subject using two-dimensional fluorescence difference gel electrophoresis and liquid chromatography coupled with tandem mass spectrometry. However, the results were obtained for only one subject. The aim of the present study was to confirm the expression of specific molecules in tendon tissues from multiple subjects with MMTAH by applying two-dimensional polyacrylamide gel electrophoresis with matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Of the 19 proteins identified in tendons from both MMTAH and facial deformity patients, fibrinogen fragment D and beta-crystallin A4 were up-regulated, whereas myosin light chain 4 was down-regulated in MMTAH. We also found fibrinogen to be expressed robustly in tendon tissues of MMTAH patients. Our data provide the possibility that the distinctive expression of these novel proteins is associated with the pathology of MMTAH.
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