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PubMed2025

Clinical carbapenem-resistant Enterobacterales in a University Hospital in Dakar, Senegal: genomic insights into Enterobacter hormaechei ST182 strains carrying blaNDM-5 and blaOXA-48 genes .

Senegal has witnessed the emergence and spread of carbapenem-resistant Enterobacterales (CRE), which often cause deadly infections. Accordingly, this study aimed to determine the antimicrobial susceptibility and prevalence of carbapenemases, as well as to perform a whole-genome sequence analysis of clinical CRE isolates from a university hospital in Dakar, Senegal. MALDI-TOF MS and VITEK2 systems were used for bacterial identification and antimicrobial susceptibility testing (AST). Carbapenemase- and cephalosporinase-encoding genes were screened using simplex end-point polymerase chain reaction. Whole-genome sequencing (WGS) was performed using the Illumina MiSeq platform. The CRE isolates were resistant to almost all the 34 antimicrobials tested. Nevertheless, colistin and amikacin remained active, with susceptibility rates of 96% and 71%, respectively. Only the carbapenemase genes blaOXA-48 (53.8%; 15/28) and blaNDM (35.7%; 10/28) and the cephalosporinase gene blaCMY-1 (25%; 7/28) were identified. In this context, two extensively drug-resistant Enterobacter hormaechei isolates were subjected to WGS analysis. These isolates were assigned as sequence type (ST) 182 and carried several genes related to antimicrobial resistance (AMR), metal tolerance, and virulence. An IncL/M plasmid with 61,054 bp in length was identified as carrying the blaOXA-48 gene, whereas an IncFIB(pECLA)/IncFII(pECLA)/IncX3 mutireplicon plasmid with 217,745 bp in length was detected as harboring the blaNDM-5 gene and other genes related to AMR and metal tolerance. Our study presents the first landscape of clinical CRE circulating in Senegal, along with additional genomic analysis of E. hormaechei ST182 strains, which could be useful for mitigating the burden associated with CRE in this country.IMPORTANCEThe investigation of global critical priority CRE isolates has become crucial to reduce morbidity and mortality associated with AMR. This study revealed that colistin and amikacin can be considered good alternatives for treating CRE-associated infections in Dakar. In addition, the genomic approach revealed that the CRE isolates carried both a wide resistome and virulome. Moreover, the abundance of horizontal gene transfer regions in the genomes suggests the great implications of mobile genetic elements in the spread of AMR in Dakar. Furthermore, this study reported the complete sequences of chromosomes and blaOXA-48 and blaNDM-5-carrying plasmids. Our findings are of great importance because complete genome sequences are still rarely characterized in the West African region. Finally, this study highlights the importance of strengthening genomic surveillance of CRE in sub-Saharan African countries to mitigate the burden associated with these pathogens.

Senegal↗

PubMed2026

A rapid molecular assay for the detection of hypervirulent Klebsiella pneumoniae in the context of antimicrobial resistance surveillance.

Hypervirulent Klebsiella pneumoniae (hvKP) represents an emerging clinical and public-health concern, particularly as hypervirulence increasingly converges with multidrug resistance. Current diagnostic approaches rely on phenotypic assays, such as the string test, or on whole-genome sequencing (WGS), both of which have limitations in specificity, turnaround time, standardization, and feasibility for routine surveillance. To address this gap, we developed a multiplex real-time PCR assay targeting key hvKP-associated virulence loci, including siderophore systems, hypermucoviscosity regulators, and additional markers linked to invasive potential. The assay was evaluated on 110 K. pneumoniae clinical isolates and 9 positive blood cultures, using WGS and the string test as comparators. The molecular panel demonstrated high concordance with WGS for principal virulence determinants, correctly identifying all high-virulence (score 4) profiles, and most intermediate profiles. Against WGS, the assay yielded a sensitivity of 82% and a specificity of 73%; performance against the string test was 96% and 87%, respectively. Direct testing from blood culture pellets yielded results consistent with both WGS and DNA-based PCR for the limited number of targets detected, supporting the technical feasibility of this approach. However, broader validation is needed to confirm performance in this specimen type. Overall, this multiplex PCR assay provides a targeted molecular screening approach for the rapid identification of hvKP-associated virulence profiles. Its agreement with genomic data supports its potential utility as an accessible complement to WGS for hvKP surveillance, although further workflow optimization will be required before broader routine implementation.IMPORTANCEThe global emergence of hypervirulent and multidrug-resistant K. pneumoniae represents a major public-health threat, as the convergence of virulence and antimicrobial resistance dramatically limits therapeutic options and increases the likelihood of severe, invasive, and potentially untreatable infections. Rapid identification of essential virulence determinants is therefore critical for timely clinical management and for preventing onward transmission. However, current diagnostic approaches are either insufficiently sensitive or require substantial resources, limiting their routine use. By providing a rapid and targeted molecular assay capable of detecting the principal loci associated with hypervirulent K. pneumoniae and by demonstrating the preliminary feasibility of its use directly on blood culture pellets previously identified as Klebsiella spp. by MALDI-TOF MS, this work provides a pragmatic approach for early virulence profiling. Implementation of such assays can significantly enhance epidemiological surveillance, support tailored patient management, and reduce the spread of high-risk K. pneumoniae lineages in both community and healthcare environments.

Klebsiella pneumoniae↗

PubMed2026

Genomic Diversity and Extended-Spectrum β-Lactamase Gene Contexts of Community Resident-Carried Escherichia coli in Ecuador.

Community carriage of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli represents an important reservoir of antimicrobial resistance. However, the genomic diversity and population structure of ESBL-producing E. coli circulating in community settings remain poorly characterized. This study aimed to characterize ESBL-producing E. coli isolated from fecal samples of residents in Ecuador, with an emphasis on the diversity and genomic context of ESBL genes. ESBL-producing E. coli was isolated from fecal samples obtained from 55 residents using MacConkey agar supplemented with cefotaxime. Whole-genome sequencing of the isolates was performed using a hybrid approach combining long- and short-read platforms. Plasmids and β-lactamase genes were identified using DFAST and PlasmidFinder. Bacterial identification and antimicrobial susceptibility testing were conducted by MALDI-TOF MS and the broth microdilution method, respectively. ESBL-producing E. coli were isolated from 35 of 55 fecal samples (63.6%). Complete circular genomes were obtained from 31 isolates. All isolates harbored bla CTX-M genes, predominantly belonging to the bla CTX-M-1 group, whereas 65.7% carried bla TEM, mainly bla TEM-1, and related variants. Although β-lactamase genes were predominantly plasmid-borne, chromosomal integration was detected in 40% of the isolates. Notably, 87.5% of the isolates harbored IncF plasmids with multiple replicons. Conserved IS26-flanked transposons carrying bla CTX-M and bla TEM were frequently identified in the plasmids. Phylogenetic analysis revealed substantial genomic diversity across seven phylogroups, together with closely related isolates detected within and between households. These findings provide high-resolution genomic insights into the ESBL determinants circulating in community residents and reveal region-specific patterns of ESBL genomic diversity.

CTX-M β-lactamases↗

PubMed2026

Oxford Nanopore Sequencing of Clinical DNA for Identification and Comparative Genomic Analysis of Erysipelothrix piscisicarius.

The genus Erysipelothrix comprises facultative anaerobic, nonspore-forming, gram-positive bacteria that can cause skin infections and severe diseases such as septicemia and endocarditis in humans. Although E. rhusiopathiae is the primary pathogen, other species may also be involved, necessitating accurate identification. However, 16S rDNA sequencing lacks sufficient resolution to differentiate among Erysipelothrix species. In this study, we used Oxford Nanopore Technology (ONT) to directly sequence low-quality DNA extracted from heart valve tissue of a 66-year-old female patient with a fatal case of septicemia and aortic endocarditis. In contrast to 16S rDNA Illumina sequencing and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), which incorrectly identified the pathogen as E. rhusiopathiae, direct sequencing via ONT precisely identified E. piscisicarius as the cause of infection. About 1.47 Mb genome was retrieved from nanopore direct sequencing. Within the E. piscisicarius genome, we detected genes associated with virulence. Phylogenetic analysis showed that our strain clustered with a human-derived E. piscisicarius strain from China and swine-derived strains from Brazil. In conclusion, this study demonstrated that ONT can be used to sequence low-quality DNA extracted directly from patient specimens, obtain a draft bacterial genome, and reliably distinguish between pathogenic species.

Aged↗

PubMed2026

Achromobacter species in cystic fibrosis and chronic lung disease: a review of virulence, antibiotic resistance, diagnostic challenges, and emerging therapies.

Achromobacter species (spp) is an emerging opportunistic organism more frequently isolated from immunocompromised patients' and hospital settings. This bacterium was once considered an environmental bacterium, but now it is recognized as a serious cause of respiratory infections, bloodstream infections, and urinary tract infections, particularly among patients with cystic fibrosis (CF), chronic illnesses, and medical devices. The purpose of this review is to highlight Achromobacte's clinical significance, pathogenic mechanism, and recent approaches for diagnosis and treatment. By utilizing specific keywords relevant to Achromobacter spp., a comprehensive literature search was performed in PubMed and Google Scholar. To summarize existing knowledge and highlight gaps in the literature, peer-reviewed studies on clinical relevance, pathogenicity, antimicrobial resistance, and therapeutic approaches were gathered, screened, and narratively assembled. Among the 19 identified species, Achromobacter xylosoxidans (A. xylosoxidans) is the most prevalent and clinically relevant, especially in CF settings. This review explores the organism's microbiological characteristics, virulence strategies-including robust biofilm formation, motility, and secretion systems-and its alarming intrinsic and acquired resistance to antibiotics. Misidentification due to phenotypic overlap with other non-fermenting Gram-negative bacilli complicates diagnosis, while limited MALDI-TOF MS and database representation hinders species-level identification. Genotyping methods, including multi-locus sequence analysis and housekeeping gene sequencing, offer superior resolution but remain underutilized in clinical diagnostics. With rising resistance mediated by β-lactamases, efflux pumps, and adaptive genomic traits, Achromobacter spp presents a growing challenge for treatment and infection control. This review highlights the urgent need for improved diagnostic strategies, species-level clinical and microbiological data, and tailored therapeutic approaches to manage Achromobacter spp. infections effectively.

Humans↗

PubMed2025

Genomic and phenotypic insights into ST164 blaNDM-1-positive Acinetobacter baumannii from intestinal colonization in China.

BACKGROUND: Carbapenem-resistant Acinetobacter baumannii (CRAB) poses a critical global threat, especially in ICUs. Yet, reports on ST164 CRAB harboring blaNDM-1 remain scarce. This study investigates two clinical CRAB isolates, L4773hy and L4796hy, derived from intestinal colonization in Hangzhou, China, focusing on their phenotypic and genomic characteristics as well as the broader transmission of ST164 A. baumannii. METHODS: Bacterial identification was performed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) mass spectrometry. Antimicrobial susceptibility was assessed via agar and broth microdilution. Whole-genome sequencing employed Illumina NovaSeq 6000 and Oxford Nanopore platforms. Resistance genes, insertion elements, transposons, and integrons were detected using ResFinder, PlasmidFinder, VFDB, ISFinder, pdifFinder, and IntegronFinder. Strains were typed by MLST, and a phylogenetic tree was constructed with kSNP3.0. Genetic environment diagrams were generated using Easyfig 2.2.5. RESULTS: Two blaNDM-1-carrying A. baumannii isolates exhibiting extensive resistance to carbapenems, cephalosporins, and fluoroquinolones. Whole-genome sequencing and genetic environment analysis revealed the presence of a conserved structural sequence (ISAba14-ISAba14-aphA-ISAba125-blaNDM-1-bleMBL) on their chromosomes. Phylogenetic and clonal dissemination analysis showed that ST164 CRAB is primarily distributed in China and exhibits clonal spread. Pathogenicity studies indicated that blaNDM-1-positive ST164 strains have enhanced survival under immune pressure but do not display increased virulence in infection models. CONCLUSION: This study provides the genomic and phenotypic characterization of intestinally colonized ST164 blaNDM-1 positive CRAB in Hangzhou, China. The elucidation of the genetic environment of blaNDM-1 further confirms the clonal dissemination of ST164 isolates, highlighting the importance of enhanced surveillance and infection control measures to mitigate the spread of these multidrug-resistant pathogens.

Acinetobacter baumannii↗

PubMed2026

Whole-genome profiling of antimicrobial resistance and virulence determinants in extensively-drug resistant Pseudomonas aeruginosa isolates causing ventilator associated pneumonia in Egypt.

Among critically ill ICU patients under prolonged mechanical ventilation, Pseudomonas aeruginosa is one of the most common cause of ventilator-associated pneumonia (VAP), with antimicrobial pressure leading to emergence of multidrug, extensively drug and pandrug-resistant (PDR) strains. In Egypt, very little genomic data exist on P. aeruginosa associated with VAP. This study aimed at characterizing the antimicrobial resistance (AMR) determinants, virulence repertoire, MGEs, and sequence types of two highly drug-resistant Pseudomonas aeruginosa isolates, including one pandrug-resistant colistin-resistant isolate and one extensively drug-resistant colistin-susceptible isolate from respiratory tract of Egyptian ICU patients suffering from VAP. The two isolates were identified conventionally and confirmed to the species level using MALDI-TOF MS. Antibiotic susceptibility was assessed using the VITEK-2 Compact system and the broth microdilution method. Genome analysis was performed using PATRIC, ResFinder, CARD, and Mobile Element Finder. For both isolates, resistance was found to all antibiotics routinely tested, however, one isolate had high-level colistin resistance (MIC > 64 µg/mL), while the other isolate was still colistin susceptible. Whole-genome sequencing identified two rare sequence types, ST2023 and ST2685, both 6.5-7.6 Mb in size with a 66% GC content. The presence of 21 MGEs in the SRR36105565 genome shows that it has high genomic flexibility, including a broader resistome than other strains, such as blaVIM-2 and OXA variants, aminoglycoside-modifying enzymes, crpP, and disinfectant-resistance markers. Both isolates retained large virulence determinants including Type III and Type VI secretion systems, alginate regulation genes, quorum-sensing networks, and siderophore biosynthesis clusters. It also represents one of the first genomic studies of VAP associated PDR P. aeruginosa from Egypt. The combination of widespread AMR with intact virulence supports the potential value of future genomic surveillance efforts and improved antimicrobial stewardship in local ICUs.

Pneumonia, Ventilator-Associated↗

PubMed1996

N-linked sugar chain of 55-kDa royal jelly glycoprotein.

An N-linked sugar chain from 55-kDa royal jelly glycoprotein (RJGP), which maintains the high viability of rat liver primary cultured cell and is a different molecular species from 350-kDa RJGP [Kimura et al., Biosci. Biotech. Biochem., 59, 507-509 (1995)], has been identified. The sugar chains were released by hydrazinolysis followed by N-acetylation and pyridylamination. The structural analysis of the pyridylaminated sugar chain was done by a combination of sequential exo-mannosidase digestions, MALDI-TOF MS, and 500 MHz 1H-NMR. For the carbohydrate moiety of 55-kDa RJGP, only one N-linked sugar chain has been detected. The structure has been found to be Man alpha 1-->2Man alpha 1-->6(Man alpha 1--> 2Man alpha 1-->3)Man alpha 1-->6(Man alpha 1-->2Man alpha 1-->2Man alpha 1-->3)Man beta 1-->4GlcNAc beta 1-->4GlcNAc, which is a non-processed high mannose type structure.

Animals↗

PubMed1996

Purification and substrate specificity of an endo-beta-N-acetylglucosaminidase from pea (Pisum sativum) seeds.

An endo-beta-N-acetylglucosaminidase was purified to homogeneity from the seeds of pea (Pisum sativum). The molecular mass of the purified enzyme was estimated to be 41,669 Da by MALDI-TOF MS analysis and its isoelectric point to be 4.3 by isoelectric focusing. The enzyme was stable at pH 4-7 and at 25-50 degrees C, and had the highest activity toward Man6GlcNAc2-PA at pH around 7.0. Oligomannose type sugar chains (Man9-6GlcNAc2-PA) and a hybrid type sugar chain (GlcNAc1Man5GlcNAc2-PA) were most favored substrates followed by Man5GlcNAc2-PA, Man3GlcNAc2-PA, and GlcNAc2Man3GlcNAc2-PA, but xylose-containing sugar chains (Man4-3Xyl1GlcNAc2-PA and Man3Fuc1Xyl1GlcNAc2-PA) or a biantennary complex type sugar chain (Gal2GlcNAc2Man3GlcNAc2-PA) could not be hydrolyzed by the enzyme. The Km values of the enzyme for Man5GlcNAc2-PA, Man6GlcNAc2-PA, and Man9GlcNAc2-PA were 0.40 mM, 0.25 mM, and 0.32 mM, respectively.

Base Sequence↗

PubMed1997

Primary structure of 6.5k-arginine/glutamate-rich polypeptide from the seeds of sponge gourd (Luffa cylindrica).

The amino acid sequence of 6.5k-arginine/glutamate rich polypeptide (6.5k-AGRP) from the seeds of sponge gourd (Luffa cylindrica) has been determined. The 6.5k-AGRP consists of a 47-residue polypeptide chain containing two disulfide bonds, and a molecular mass calculated to be 5695 Da, which fully coincides with a value of [M+H]+ = m/zeta 5693.39 obtained by matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS). The mass spectrometric evidence indicated that 6.5k-AGRP is also present partially truncated at the C-terminus. In our preparations, approximately half of the polypeptide molecules have the C-terminal sequence Arg-Arg-Glu-Val-Asp; the other half lack Val-Asp and end with the glutamic acid, making a total of 45 residues in the polypeptide chain. The two disulfide bonds connect Cys12 to Cys33 and Cys16 to Cys29. Comparison of the amino acid sequence of 6.5k-AGRP with those of the other known proteins included in the PIR protein sequence database showed that it is related to the amino acid sequence of the N-terminal region encoded by the first exon of the cocoa (Theobroma cacao) and cotton seeds vicilin genes, sharing a characteristic two Cys-Xaa-Xaa-Xaa-Cys motif.

Amino Acid Sequence↗

PubMed2026

Deciphering the genomic landscape of novel Acinetobacter non-baumannii lineages causing neonatal septicemia: carbapenem resistance and virulence.

BACKGROUND: Acinetobacter non-baumannii (Anb) species are reported worldwide to cause infections in both adults and neonates, although less frequently than Acinetobacter baumannii. However, limited information is available on their genomic diversity, resistance mechanisms, and virulence potential. This study investigates novel Anb isolates causing neonatal septicemia in India to characterize their resistance and pathogenic traits. METHODS: Anb isolates from neonatal blood cultures (2007-2025) were identified by VITEK2 Compact system, MALDI-TOF MS, and Whole-genome sequencing (WGS). Antimicrobial susceptibility was tested by VITEK2. Genomic analysis included MLST, resistome, virulome, plasmid typing, integrons, and core-genome phylogeny analysis. In vitro and in vivo studies assessed pathogenic potential of Anb species. RESULTS: Anb infections were low (11%) among the neonates during the study period. WGS revealed 11 novel Sequence Types (STs) which include A. indicus, A. variabilis, A. schindleri, and A. bereziniae. Six out of these eleven Anbs harbored carbapenemases such as bla NDM-1 and/or bla OXA-58-like genes (bla OXA-58, bla OXA-420). bla NDM-1 was acquired via Tn125 transposon. ISAba125 was located upstream of bla NDM-1, and a conserved structure extending to IS91 family transposase was detected in bla NDM-1-harboring genomes. bla OXA-58-like genes were found to be associated with ISAba3. Most carbapenemases were likely located on chromosome. Class 1 integrons carrying multiple antimicrobial resistance genes (ARGs) and diverse plasmid replicase families were detected in Anbs. Core genome phylogeny showed that the study Anbs were not closely related to the global Anbs. In vitro virulence-associated assays (biofilm formation, surface motility, adherence/invasion, apoptosis) and in vivo lethality in murine infection model showed reduced pathogenicity, reinforcing earlier observations that Anb species are generally less virulent than A. baumannii. Several virulence factors (VFs) were detected; however, no clear correlation was observed between virulence genes, in vitro pathogenicity, and in vivo lethality. CONCLUSION: These results indicate the multifactorial nature of Anb pathogenicity and the current limitations of knowledge of its VFs. However, the presence of numerous VFs suggests a capacity to cause disease, particularly in vulnerable host populations such as neonates. Furthermore, the presence of multiple ARGs indicates a strong potential for persistence and dissemination in hospital environments with high antibiotic pressure. Overall, these findings underscore the importance of continued AMR surveillance, genome characterization and further investigations into Anb pathogenicity.

Acinetobacter non-baumannii↗

PubMed2026

Genomic insights into Aeromonas infections in diarrheal patients: high diversity, emerging resistance, and potential outbreak in Beijing.

BACKGROUND: Aeromonas species are ubiquitous aquatic bacteria that have emerged as significant foodborne enteric pathogens worldwide, yet their genomic landscape in clinical settings remains poorly delineated, particularly in Beijing. METHODS: To address this gap, we performed active surveillance for Aeromonas among 691 consecutive diarrheal outpatients in a Beijing district from January to December 2024. Isolates were recovered using enrichment culture coupled with PCR screening and identified by MALDI-TOF MS. Antimicrobial susceptibility was tested against 17 agents. Whole-genome sequencing was conducted on all isolates, enabling average nucleotide identity (ANI) analysis, comprehensive annotation of antimicrobial resistance and virulence genes, multilocus sequence typing (MLST), and core-genome SNP (cgSNP)-based phylogenetics. RESULTS: Aeromonas was detected in 3.3% (23/691) of patients, with Aeromonas veronii (56.52%, 13/23) and Aeromonas caviae (26.09%, 6/23) predominating. Co-infections with other enteric pathogens occurred in 65.2% of positive cases. Resistance rates were notably high for ampicillin/ampicillin-sulbactam (78.26%), nalidixic acid (56.52%), and ertapenem (21.73%), and 65.21% of isolates were multidrug-resistant. Genotypic-phenotypic concordance was robust, with β-lactamase genes ampS (60.87%) and blaCEPH-A3 (47.83%) being most prevalent. Strikingly, mcr-3.25 and mcr-3.3, which belong to the mcr family (originally described as mobile colistin resistance genes), were identified in 8.70% of isolates, exhibiting perfect correlation with phenotypic resistance. Plasmer analysis suggested both mcr genes to be chromosomally encoded. Comparative genomic analysis of virulence-associated genes revealed striking species-specific specialization: A. veronii predominantly carried complete T3SS clusters (61.5%), A. caviae and Aeromonas enteropelogenes were enriched in T6SS genes, and a single A. dhakensis isolate possessed an extensive arsenal including T3SS, T6SS, and a full RTX toxin cluster. MLST resolved the 23 isolates into 22 sequence types, 18 of which were novel. Phylogenetic reconstruction identified a tight monophyletic cluster of three A. veronii isolates (9-27 SNP differences) recovered within a 96-h window, suggestive of a potential cluster that warrants further epidemiological investigation. Comparative genomic analysis of the rare species Aeromonas allosaccharophila demonstrated that the Beijing clinical isolate S14 differs from the U.S. clinical strain ATCC 35942 by 42,099 SNPs, confirming its distinct genetic lineage. CONCLUSION: Collectively, this study delineates high genetic diversity, emerging chromosomal colistin resistance, and species-specific virulence specialization among Aeromonas isolates from diarrheal patients in Beijing. The detection of a potential outbreak cluster and a rare clinical isolate underscores the power of genomics-based surveillance for detecting and mitigating foodborne pathogen threats.

Aeromonas↗

PubMed2026

[Genes determining virulence factors of Escherichia coli strains isolated from prostate secretions patients with chronic bacterial prostatitis].

UNLABELLED: The aim of the work is to characterize virulence genes of E. coli strains isolated from prostate secretions patients with chronic bacterial prostatitis. MATERIALS AND METHODS: Escherichia coli were isolated from the prostate secretions of men of reproductive age (20-45 years) with chronic bacterial prostatitis using a generally accepted bacteriological method, the type was determined using MALDI-TOF mass spectrometry, virulence genes were PCR and sequencing. RESULTS: The genomes of the studied strains contain genes encoding groups of virulence factors: adhesins, toxins, capsule antigens, siderophores, invasins, and anti-immunity of the macroorganism. Itwas shown that the genes of adhesins, siderophores, and immune system counteraction factors prevailed in E. coli. CONCLUSION: Further studies of E. coli strains using genome-wide sequencing and proteomics technologies are needed. The accumulation of the obtained data will make it possible to use virulence genes as diagnostic markers in patients with chronic prostatitis, indicating the presence of infection.

Humans↗

PubMedDate not supplied

Mass spectrometric sequencing of synthetic peptides containing alpha, alpha-dialkylated amino acid residues by MALDI post-source decay analysis.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), a method well-suited for mass determination of biomolecules, has been used to analyze fragment ions generated by post-source decay (PSD) of synthetic peptaibols containing high proportions of the sterically hindered amino acids alpha-amino isobutyric acid (Aib) and isovaline (Iva). Since peptaibols do not have a free N-terminal amino group or side chains subject to protonation, the analyzed peptides saturnisporin SA III, trichotoxin A-50 and chrysospermin B were shown to provide preferred N-terminal and C-terminal a, b, and y fragments as sodium adduct. Additionally, a cleavage of the labile Aib-Probond was observed for all peptides investigated. The fragmentation pattern allowed confirmation of the primary structure and, therefore, demonstrated the usefulness of MALDI-PSD mass spectrometry for sequence analysis of the peptaibols.

Alkylation↗

PubMed1996

[Bacterial endotoxins--methods of structural analysis].

The modern structural methods used in the determination of lipopolysaccharides chemical structures were described. The combination of nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MALDI-TOF, FAB and EI) applied to structural analysis of lipopolysaccharides, with a few chosen examples of characteristic original spectra were presented.

Bacterial Toxins↗

PubMedDate not supplied

Capillary electrophoresis for purity estimation and in-process testing of recombinant GB virus-C proteins.

Protein purity estimation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) coupled with scanning densitometry is a critical component in the manufacture of recombinant proteins for commercial diagnostic assays. However, the procedure is time consuming and often difficult to reproduce because commercial dyes that are used for visualizing proteins do not bind in a stoichiometric fashion for all proteins. The present report describes the use of a rapid and dye-independent SDS polymer-filled capillary gel electrophoresis (CE-SDS) method to estimate protein purity. The CE-SDS method was used for in-process and final purity testing of GB virus-C (GBV-C) fusion proteins produced in E. coli, and was directly compared with the conventional SDS-PAGE method using purified Coomassie blue dye to reduce protein staining anomalies. The CE-SDS method may serve as an alternative or replacement method to the lengthy and tedious SDS-PAGE method. This study also demonstrates that the observed molecular weight of the fusion protein, determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), provides higher accuracy than values estimated by either CE-SDS or SDS-PAGE methods.

Cloning, Molecular↗

PubMed2026

Burkholderia arboris bacteremia initially identified as Burkholderia cepacia complex: a genome-based case report.

We report a bloodstream Burkholderia arboris isolate from a 75-year-old man without cystic fibrosis. The organism was recovered from both aerobic bottles of two separately collected blood-culture sets and was initially assigned to the Burkholderia cepacia complex (Bcc) by matrix-assisted laser desorption ionization-time-of-flight mass spectrometry. Whole-genome sequencing yielded three circular chromosomes and one circular plasmid. DFAST_QC identified B. arboris as the only type-strain match above the species threshold, with an average nucleotide identity of 99.48%; the next-highest match was B. seminalis at 93.33%. Multilocus sequence typing identified ST-2575, and ResFinder detected no acquired antimicrobial resistance genes. The patient improved after 14 days of meropenem therapy without recurrent B. arboris bacteremia. This report adds a clinically supported bloodstream infection, a complete genome resource, and detailed susceptibility data, while illustrating the importance of up-to-date reference genomes for species-level interpretation of unusual Bcc isolates.

Humans↗

PubMed2026

Development and validation of a serum peptidomic signature for early detection of asymptomatic ovarian cancer: A multi-center prospective study.

Early detection of asymptomatic ovarian cancer (asym-OC) remains a critical challenge, the failure of which underlies its high mortality. Performing serum peptidomic profiling of 843 participants in the cohort SOCFCP, we distill 1,081 initial features into a 7-marker panel for asym-OC detection via a biology-informed machine-learning (ML)-based feature selection strategy. Three markers significantly revert toward non-OC levels after surgery. Integrating the panel with age, CA125, and HE4, we develop and externally validate (n = 159) a LightGBM model, ProMS+. For early-stage OC detection, ProMS+ shows a specificity of 92.6% at 95.0% sensitivity, outperforming CA125 (44.7%), HE4 (11.2%), and Risk of Ovarian Malignancy Algorithm (ROMA) (24.0%), with an area under the curve (AUC) of 0.993. In a simulated high-risk population (n = 100,000; OC prevalence = 1%), ProMS+ yields a high AUC (0.983) and a higher positive predictive value than CA125, HE4, and Age + CA125 + HE4 combined model (0.201 vs. 0.027, 0.090, and 0.064). ProMS+ offers a promising, non-invasive, and interpretable approach for the early detection of asym-OC.

Humans↗