Impact of Ultrafiltration on the Physicochemical Properties of Bovine Lactoferrin: Insights into Molecular Mass, Surface Morphology, and Elemental Composition.

The large-scale isolation of bovine lactoferrin (bLF) typically involves using large amounts of concentrated eluents, which might introduce impurities to the final product. Sometimes, protein pre-concentration is required for the greater accuracy of experimental results. In this research, the supplied bLF sample was subjected to additional ultrafiltration (UF) to eliminate possible small impurities, such as salts and peptides of bLF. Beforehand, the basic characterization of native bLF, including surface-charge properties and the structural sensitivity to the various pH conditions, was performed. The study aimed to evaluate the difference in molecular mass, primary structure, surface morphology, and elemental composition of the protein before and after UF. The research was provided by application of spectroscopic, spectrometric, electrophoretic, and microscopic techniques. The evident changes in the surface morphology of bLF were observed after UF, while the molecular masses of both proteins were comparable. According to MALDI-TOF/MS results, UF had a positive impact on the bLF sample representation, improving the identification parameters, such as sequence coverage and intensity coverage.

Expansion of MALDI-TOF MS database as a strategy for identification of Haemophilus species other than H. influenzae.

OBJECTIVES: This study aimed to evaluate an expanded matrix-assisted laser desorption-ionization-time of flight mass spectrometry (MALDI-TOF MS) database for the identification of Haemophilus species other than H. influenzae (Hi). METHODS: A total of 144 Haemophilus species, cultured from respiratory samples from people (living) with cystic fibrosis, were identified with MALDI-TOF MS and 16S rRNA sequencing. Of these, 99 Haemophilus strains showed >99% similarity with the best matching strain in the National Center for Biotechnology Information (NCBI) database and were assigned to a single Haemophilus subspecies using both MALDI-TOF MS and 16S rRNA sequencing. The MS profiles of a subset of strains (n = 58/99) were added to the Bruker MALDI-TOF MS database. Subsequently, 270 different strains that were analyzed previously in a routine setting were re-analyzed. RESULTS: 16S rRNA sequencing reliably identified 99/144 Haemophilus strains (>99% similarity). H. haemolyticus 16S rRNA identification was suboptimal since only 3/21 H. haemolyticus strains attained a similarity of >99% with H. haemolyticus 16S rRNA sequence in the NCBI database. Expansion of the MALDI-TOF MS database improved the number of reliable identifications only moderately for H. haemolyticus, H. influenzae and H. paraphrohaemolyticus (<10%). By contrast, improved identification was more outspoken for H. parahaemolyticus, H. parainfluenzae, H. sputorum and H. pittmaniae (>85%). CONCLUSION: 16S rRNA sequencing is a valuable method for the identification of Haemophilus sp. other than Hi. Expansion of the MALDI-TOF MS database, based on 16S rRNA sequencing results, increased the proportion of reliable identifications and in this study resulted in an increase of 10% of Haemophilus sp. other than Hi strain identifications.

Modelling the rapid detection of Carbapenemase-resistant Klebsiella pneumoniae based on machine learning and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

In this study, 80 carbapenem-resistant Klebsiella pneumoniae (CR-KP) and 160 carbapenem-susceptible Klebsiella pneumoniae (CS-KP) strains detected in the clinic were selected and their matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) peaks were collected. K-means clustering was performed on the MS peak data to obtain the best "feature peaks", and four different machine learning models were built to compare the area under the ROC curve, specificity, sensitivity, test set score, and ten-fold cross-validation score of the models. By adjusting the model parameters, the test efficacy of the model is increased on the basis of reducing model overfitting. The area under the ROC curve of the Random Forest, Support Vector Machine, Logistic Regression, and Xgboost models used in this study are 0.99, 0.97, 0.96, and 0.97, respectively; the model scores on the test set are 0.94, 0.91, 0.90, and 0.93, respectively; and the results of the ten-fold cross-validation are 0.84, 0.81, 0.81, and 0.85, respectively. Based on the machine learning algorithms and MALDI-TOF MS assay data can realize rapid detection of CR-KP, shorten the in-laboratory reporting time, and provide fast and reliable identification results of CR-KP and CS-KP.

Integrating multi-wet laboratory diagnostics to study staphylococci in animals in Uganda.

BACKGROUND: Several diagnostic environments in Uganda lack real-time, robust and high-throughput technologies for comprehensive typing of microbes, which is a setback to infectious disease surveillance. This study combined various wet laboratory diagnostics to understand the epidemiology of pathogenic staphylococci isolated from animals in Uganda and the implications for global health security priorities. METHODS: A retrospective study was conducted employing records and pathogenic staphylococci (from animals) archived at the Central Diagnostic Laboratory (CDL), Makerere University, Uganda, between January 2012 and December 2019. The bacteria were speciated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and tested for virulence factors [beta lactamases, lecithinase, deoxyribonuclease (DNase), haemolysins] and resistance to ten antimicrobials of clinical and veterinary relevance. Tetracycline and methicillin resistance genes were also tested. RESULTS: The prevalent diseases were mastitis in cattle and skin infections in dogs. Of the 111 staphylococci tested by MALDI-TOF MS, 79 (71.2%) were Staphylococcus aureus, 27 (24.3%) were Staphylococcus pseudintermedius and 5 (4.5%) were Staphylococcus schleiferi. All these strains expressed haemolysins. The prevalence of strains with lecithinase, penicillinase, cephalosporinase and DNase was 35.9% (14/39), 89.7% (35/39), 0.0% (0/39) and 87.2% (34/39), respectively. Staphylococci were primarily resistant to early penicillins (over 80%), tetracycline (57.7%), and chloramphenicol (46.2%). Minimal resistance was noted with cloxacillin (0.0%), ciprofloxacin (9.6%), and cefoxitin (3.8%). The prevalence of multidrug resistance (MDR) was 78.8% for general staphylococci, 82.2% for S. aureus, 73.1% for S. pseudintermedius, and 60.0% for S. schleiferi. Multidrug resistant staphylococci were significantly more prevalent in the cattle isolates than in the dog isolates (P < 0.05). The prevalence of methicillin-resistant staphylococci (MRS) tested by resistance to cefoxitin and mecA carriage was 3.8%. These four strains were all isolated from dog skin infections. The tetK gene was the most predominant (35.4%), followed by tetM (25.0%). CONCLUSION: In resource-constrained settings, the approach of integrated diagnostics promises sustainable disease surveillance and the addressing of current capacity gaps. The emergence of MRS (zoonotic bacteria) in companion animals creates a likelihood of reduced treatment options for related human infections, a threat to global health.

Enhanced diagnosis of pulmonary tuberculosis through nucleotide MALDI-TOF MS analysis of BALF: a retrospective clinical study.

To evaluate the diagnostic accuracy of matrix-assisted laser desorption ionization time-of-flight mass spectrometry based on nucleotide (nucleotide MALDI-TOF MS) on bronchoalveolar lavage fluid (BALF) from suspected pulmonary tuberculosis (PTB) patients. A retrospective study was conducted on suspected PTB patients (total of 960) admitted to Chongqing Public Health Medical Center between May 2021 and January 2022. The sensitivity, specificity, positive predictive value, negative predictive value (NPV) and area under the curve values of nucleotide MALDI-TOF MS as well as smear microscopy, Mycobacterium Growth Indicator Tube 960 culture (MGIT culture), and Xpert MTB/RIF were calculated and compared. Total of 343 presumed PTB cases were enrolled. Overall, using the clinical diagnosis as reference, the sensitivity and NPV of nucleotide MALDI-TOF MS was 71.5% and 43.1%, respectively, significantly higher than smear microscopy (22.6%, 23.2%), MGIT culture (40.6%, 18.9%), Xpert MTB/RIF (40.8%, 27.9%). Furthermore, nucleotide MALDI-TOF MS also outperformed over Xpert MTB/RIF and MGIT culture on smear-negative BALFs. Approximately 50% and 30% of patients benefited from nucleotide MALDI-TOF MS compared with smear and MGIT culture or Xpert MTB/RIF, respectively. This study demonstrated that the analysis of BALF with nucleotide MALDI-TOF MS provided an accurate and promising tool for the early diagnosis of PTB.

The first case of urosepsis caused by Corynebacterium aurimucosum in an immunocompetent patient.

Non-diphtheroid Corynebacterium sepsis is rare and has affected only immunocompromised or particularly predisposed patients so far. We present the first case of urosepsis caused by Corynebacterium aurimucosum in a 67-year-old woman, without any known immunodeficiencies and in absence of any immunosuppressive therapy, admitted to the hospital for fever and acute dyspnea. This work suggests a new approach in evaluating the isolation of Corynebacteria, especially if isolated from blood. In particular, it highlights the potential infectious role of C. aurimucosum (often considered a contaminant and only rarely identified as an etiological agent of infections) and its clinical consequences, detailing also interesting aspects about its microbiological diagnosis and relative therapy and clarifying contrasting data of literature.

[Box: see text].

Predicting Pseudomonas aeruginosa drug resistance using artificial intelligence and clinical MALDI-TOF mass spectra.

Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) is widely used in clinical microbiology laboratories for bacterial identification but its use for detection of antimicrobial resistance (AMR) remains limited. Here, we used MALDI-TOF MS with artificial intelligence (AI) approaches to successfully predict AMR in Pseudomonas aeruginosa, a priority pathogen with complex AMR mechanisms. The highest performance was achieved for modern ß-lactam/ß-lactamase inhibitor drugs, namely, ceftazidime/avibactam and ceftolozane/tazobactam. For these drugs, the model demonstrated area under the receiver operating characteristic curve (AUROC) of 0.869 and 0.856, specificity of 0.925 and 0.897, and sensitivity of 0.731 and 0.714, respectively. As part of this work, we developed dynamic binning, a feature engineering technique that effectively reduces the high-dimensional feature set and has wide-ranging applicability to MALDI-TOF MS data. Compared to conventional feature engineering approaches, the dynamic binning method yielded highest performance in 7 of 10 antimicrobials. Moreover, we showcased the efficacy of transfer learning in enhancing the AUROC performance for 8 of 11 antimicrobials. By assessing the contribution of features to the model's prediction, we identified proteins that may contribute to AMR mechanisms. Our findings demonstrate the potential of combining AI with MALDI-TOF MS as a rapid AMR diagnostic tool for Pseudomonas aeruginosa.IMPORTANCEPseudomonas aeruginosa is a key bacterial pathogen that causes significant global morbidity and mortality. Antimicrobial resistance (AMR) emerges rapidly in P. aeruginosa and is driven by complex mechanisms. Drug-resistant P. aeruginosa is a major challenge in clinical settings due to limited treatment options. Early detection of AMR can guide antibiotic choices, improve patient outcomes, and avoid unnecessary antibiotic use. Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) is widely used for rapid species identification in clinical microbiology. In this study, we repurposed mass spectra generated by MALDI-TOF and used them as inputs for artificial intelligence approaches to successfully predict AMR in P. aeruginosa for multiple key antibiotic classes. This work represents an important advance toward using MALDI-TOF as a rapid AMR diagnostic for P. aeruginosa in clinical settings.

A Case Report of a Rare Pulmonary Opportunistic Infection in an Infant Caused by Tsukamurella tyrosinosolvens.

This case report describes the case of a female infant hospitalized for severe pneumonia. During the treatment process, various antibiotics are used to treat and prevent further infection. The child had a weak physical condition, combined with neuroblastoma, paraneoplastic syndrome, and low immune function, leading to Tsukamurella tyrosinosolvens infection. The treatment was eventually abandoned owing to poor prognosis. This study aims to through the medium, dyeing, electron microscope observation, 16s rRNA and high-throughput sequencing investigated the morphological characteristics, staining properties, electron microscope morphology, antibiotic resistance, and genomic characteristics of Tsukamurella tyrosinosolvens. The aim of the study is to provide data reference for clinical laboratory staff in bacteria identification research, and to provide relevant help for clinicians in diagnosis and treatment.

In silico-driven identification and experimental confirmation of antifungal proteins (AFPs) against Candidaalbicans.

Mycoses infect millions of people annually across the world. The most common mycosis agent, Candida albicans is responsible for a great deal of illness and death. C. albicans infection is becoming more widespread and the current antifungals polyenes, triazoles, and echinocandins are less efficient against it. Investigating antifungal peptides (AFPs) as therapeutic is gaining momentum. Therefore, we used MALDI-TOF/MS analysis to identify AFPs and protein-protein docking to analyze their interactions with the C. albicans target protein. Some microorganisms with strong antifungal action against C. albicans were selected for the isolation of AFPs. Using MALDI-TOF/MS, we identified 3 AFPs Chitin binding protein (ACW83017.1; Bacillus licheniformis), the bifunctional protein GlmU (BBQ13478.1; Stenotrophomonas maltophilia), and zinc metalloproteinase aureolysin (BBA25172.1; Staphylococcus aureus). These AFPs showed robust interactions with C. albicans target protein Sap5. We deciphered some important residues in identified APFs and highlighted interaction with Sap5 through hydrogen bonds, protein-protein interactions, and salt bridges using protein-protein docking and MD simulations. The three discovered AFPs-Sap5 complexes exhibit different levels of stability, as seen by the RMSD analysis and interaction patterns. Among protein-protein interactions, the remarkable stability of the BBQ25172.1-2QZX complex highlights the role of salt bridges and hydrogen bonds. Identified AFPs could be further studied for developing successful antifungal candidates and peptide-based new antifungal therapeutic strategies as fresh insights into addressing antifungal resistance also.

Flavonifractor plautii Bacteremia With Generalized Peritonitis: A Case Report and Literature Review.

Flavonifractor plautii is an obligate anaerobic rod bacterium that is part of the human gut microbiota. We describe a case of bacteremia caused by F. plautii in a mildly immunocompromised patient with acute generalized peritonitis. The patient is an 83-year-old male, with a history of stage III hepatocellular carcinoma 11 months prior, stage I gastric cancer, and cerebral infarction three months prior. He visited the emergency room of our hospital with a chief complaint of right-sided abdominal pain. A partial resection of the colon was performed due to stenosis of the transverse colon. Due to increasing abdominal pain, the patient underwent surgery for acute generalized peritonitis on the 11th postoperative day. F. plautii was detected in blood cultures collected prior to surgery, and the patient was treated with piperacillin/tazobactam 2.25 g four times a day for 11 days. The patient resumed eating and was discharged with no recurrence. This species may also stain gram-negative, and caution should be exercised in reporting results due to the potential impact on initial antimicrobial therapy. Gram staining showed variation in the length of the bacterium, which is considered a characteristic of this species. Appropriate antimicrobial therapy for F. plautii has yet to be established, and further accumulation of cases is needed to understand the resistance mechanism and confirm the effectiveness of different antimicrobials.

Comparison of Vaginal microbiota in HPV-negative and HPV-positive pregnant women using a culture-based approach.

The purpose of this study was to conduct a comparative analysis of the composition of the dominant groups of vaginal microorganisms in healthy pregnant women and pregnant women infected with HPV using a microbiological culture-based method. The MALDI TOF MS method and 16S rRNA gene fragment sequencing were used to identify microorganisms isolated from healthy pregnant women (n=32) and pregnant women infected with HPV (n=24). It was found that vaginal secretion samples from both groups contained bacteria of 4 phyla: Bacillota, Actinomycetota, Pseudomonadota, Bacteroidota, and Ascomycota fungi. The most common microbial community in healthy pregnant women being CST I (p=0.0007), and CST V in pregnant women infected with HPV (p=0.0001). At the genus level, a total of 25 taxa were found in all samples, with Lactobacillus being the dominant genus overall. Escherichia (p<0.0001) and Prevotella (p=0.0001) concentrations were higher in HPV infected patients. When calculating the Pearson correlation coefficient for the phyla, it was found that Bacillota correlated negatively with HPV genotypes 16 and 51 (p≤0.05), but positively with HPV genotype 59 (p≤0.05), just like Actinomycetota (p≤0.05). Bacteroidota correlated positively with HPV genotype 56 (0.001

Rapid detection of ceftriaxone-resistant Salmonella by matrix-assisted laser desorption-ionization time-of-flight mass spectrometry combined with the ratio of optical density.

BACKGROUND: The increased resistance rate of Salmonella to third-generation cephalosporins represented by ceftriaxone (CRO) may result in the failure of the empirical use of third-generation cephalosporins for the treatment of Salmonella infection in children. The present study was conducted to evaluate a novel method for the rapid detection of CRO-resistant Salmonella (CRS). METHODS: We introduced the concept of the ratio of optical density (ROD) with and without CRO and combined it with matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS) to establish a new protocol for the rapid detection of CRS. RESULTS: The optimal incubation time and CRO concentration determined by the model strain test were 2 h and 8 µg/ml, respectively. We then conducted confirmatory tests on 120 clinical strains. According to the receiver operating characteristic curve analysis, the ROD cutoff value for distinguishing CRS and non-CRS strains was 0.818 [area under the curve: 1.000; 95% confidence interval: 0.970-1.000; sensitivity: 100.00%; specificity: 100%; P < 10- 3]. CONCLUSIONS: In conclusion, the protocol for the combined ROD and MALDI-TOF MS represents a rapid, accurate, and economical method for the detection of CRS.

Discovery, identification and mechanism of chemosensitivity-relate biomarker inter-α-trypsin inhibitor heavy chain 4 in metastatic colorectal cancer.

Predictive biomarkers of response to chemotherapy in patients with metastatic colorectal cancer (mCRC) are needed to better characterize tumors and enable more tailored therapies. Here we used serum proteomics to screen for chemotherapy predictive markers. We found that higher baseline serum inter-α-trypsin inhibitor Heavy Chain 4 (ITIH4) expression in newly diagnosed mCRC patients was associated with poorer response to standard first-line chemotherapy. In addition, the higher expression of ITIH4 in CRC tissue also suggested poorer prognosis mCRC patients. Moreover, the overexpression of ITIH4 could promote the proliferation of CRC cells and reduce the sensitivity of CRC cells to 5-fluorouracil (5-FU) by inhibiting apoptosis in vivo and vitro. Through RNA-seq combined with bioinformatics analysis, we speculated that ITIH4 may activate phosphatidyl 3-kinase-protein kinase B (PI3K-AKT) pathway to inhibit apoptosis, thereby reducing the sensitivity of CRC cells to 5-FU. In conclusion, our findings unveil that ITIH4 is associated with CRC resistance to 5-FU, and may serve as a potential predictive biomarker for the sensitivity of advanced CRC patients to standard first-line chemotherapy regimens, and also provide a potential therapeutic target to render 5-FU resistance in CRC patients.

Invasive Fusarium solani infection diagnosed by traditional microbial detection methods and metagenomic next-generation sequencing in a pediatric patient: a case report and literature review.

Fusarium solani, as an opportunistic pathogen, can infect individuals with immunosuppression, neutropenia, hematopoietic stem cell transplantation (HSCT), or other high-risk factors, leading to invasive or localized infections. Particularly in patients following allogeneic HSCT, Fusarium solani is more likely to cause invasive or disseminated infections. This study focuses on a pediatric patient who underwent HSCT for severe aplastic anemia. Although initial blood cultures were negative, an abnormality was detected in the 1,3-ß-D-glucan test (G test) post-transplantation. To determine the causative agent, blood samples were subjected to metagenomic next-generation sequencing (mNGS) and blood cultures simultaneously. Surprisingly, the results of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and mNGS differed slightly, with mNGS identifying Nectria haematonectria, while MALDI-TOF MS based on culture showed Fusarium solani. To clarify the results, Sanger sequencing was performed for further detection, and the results were consistent with those of MALDI-TOF MS. Since the accuracy of Sanger sequencing is higher than that of mNGS, the diagnosis was revised to invasive Fusarium solani infection. With advancements in technology, various detection methods for invasive fungi have been developed in recent years, such as mNGS, which has high sensitivity. While traditional methods may be time-consuming, they are important due to their high specificity. Therefore, in clinical practice, it is essential to utilize both traditional and novel detection methods in a complementary manner to enhance the diagnosis of invasive fungal infections.

Iron-binding biomolecules in the soluble hepatic fraction of the northern pike (Esox lucius): two-dimensional chromatographic separation with mass spectrometry detection.

Iron plays vital roles in important biological processes in fish, but can be toxic in high concentrations. The information on metalloproteins that participate in maintenance of Fe homeostasis in an esocid fish, the northern pike, as an important freshwater bioindicator species, are rather scarce. The aim of this study was to identify main cytosolic constituents that sequester Fe in the northern pike liver. The method applied consisted of two-dimensional HPLC separation of Fe-binding biomolecules, based on anion-exchange followed by size-exclusion fractionation. Apparent molecular masses of two main Fe-metalloproteins isolated by this procedure were ~360 kDa and ~50 kDa, with the former having more acidic pI, and indicated presence of ferritin and hemoglobin, respectively. MALDI-TOF-MS provided confirmation of ferritin subunit with a m/z peak at 20.65 kDa, and hemoglobin with spectra containing main m/z peak at 16.1 kDa, and smaller peaks at 32.1, 48.2, and 7.95 kDa (single-charged Hb-monomer, dimer, and trimer, and double-charged monomer, respectively). LC-MS/MS with subsequent MASCOT database search confirmed the presence of Hb-ß subunits and pointed to close relation between esocid and salmonid fishes. Further efforts should be directed towards optimization of the conditions for metalloprotein analysis by mass spectrometry, to extend the knowledge on intracellular metal-handling mechanisms.

Candida albicans in the oral cavities of pets: biofilm formation, putative virulence, antifungal resistance profiles and classification of the isolates.

The study aimed to investigate Candida albicans presence, antifungal resistance, biofilm formation, putative virulence genes, and molecular characterization in oral samples of dogs and cats. A total of 239 oral samples were collected from cats and dogs of various breeds and ages at Erciyes University, Faculty of Veterinary Medicine Clinics, between May 2017 and April 2018. Among 216 isolates obtained, 15 (6.95%) were identified as C. albicans, while 8 (3.7%) were non-albicans Candida species. Antifungal susceptibility testing revealed sensitivities to caspofungin, fluconazole, and flucytosine in varying proportions. Molecular analysis indicated the presence of fluconazole and caspofungin resistance genes in all C. albicans isolates. Additionally, virulence genes ALS1, HWP1, and HSP90 showed variable presence. Biofilm formation varied among isolates, with 46.7% strong, 33.3% moderate, and 20% weak producers. PCA analysis categorized isolates into two main clusters, with some dog isolates grouped separately. The findings underscore the significance of oral care and protective measures in pets due to C. albicans prevalence, biofilm formation, virulence factors, and antifungal resistance in their oral cavity, thereby aiding clinical diagnosis and treatment in veterinary medicine.

Formic acid sandwich method is well-suited for filamentous fungi identification and improves turn around time using Zybio EXS2600 mass spectrometry.

OBJECTIVES: Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is extensively employed for the identification of filamentous fungi on MALDI Biotyper (Bruker Daltonics) and Vitek MS (biomerieux), but the performance of fungi identification on new EXS2600 (Zybio) is still unknow. Our study aims to evaluate the new EXS2600 system's (Zybio) ability to rapidly identify filamentous fungi and determine its effect on turnaround time (TAT) in our laboratory. METHODS: We tested 117 filamentous fungi using two pretreatment methods: the formic acid sandwich (FA-sandwich) and a commercial mold extraction kit (MEK, Zybio). All isolates were confirmed via sequence analysis. Laboratory data were extracted from our laboratory information system over two 9-month periods: pre-EXS (April to December 2022) and post-EXS (April to December 2023), respectively. RESULTS: The total correct identification (at the species, genus, or complex/group level) rate of fungi was high, FA-sandwich (95.73%, 112/117), followed by MEK (94.02%, 110/117). Excluding 6 isolates not in the database, species-level identification accuracy was 92.79% (103/111) for FA-sandwich and 91.89% (102/111) for MEK; genus-level accuracy was 97.29% (108/111) and 96.39% (107/111), respectively. Both methods attained a 100% correct identification rate for Aspergillus, Lichtheimia, Rhizopus Mucor and Talaromyces species, and were able to differentiate between Fusarium verticillioides and Fusarium proliferatum within the Fusarium fujikuroi species complex. Notably, high confidence was observed in the species-level identification of uncommon fungi such as Trichothecium roseum and Geotrichum candidum. The TAT for all positive cultures decreased from pre EXS2600 to post (108.379 VS 102.438, P < 0.05), and the TAT for tissue decreased most (451.538 VS 222.304, P < 0.001). CONCLUSIONS: The FA-sandwich method is more efficient and accurate for identifying filamentous fungi with EXS2600 than the MEK. Our study firstly evaluated the performance of fungi identification on EXS2600 and showed it is suitable for clinical microbiology laboratories use.

A case of Aspergillus quadrilineatus pulmonary infection in China.

A 91-year-old Chinese male was hospitalized on June 28, 2021, due to a sudden fever. The patient had a long history of smoking, a 10-year history of type 2 diabetes, a family history of hypertension, and a history of coronary heart disease and lower extremity arterial occlusive disease. He presented with cough, sputum, and dry and wet rales in both lungs. A computed tomography scan revealed multiple infectious lesions in both lungs and a small pleural effusion. His procalcitonin level was 1.75 ng/mL. Microscopic examination of the sputum revealed abundant fungal spores and hyphae. Sputum culture results revealed Aspergillus quadrilineatus, which was confirmed by matrix-assisted laser desorption/ionization time-of-flight and internal transcribed spacer gene sequencing. Fungal drug sensitivity testing revealed that azoles (excluding fluconazole) and echinocandins exhibited high activity against Aspergillus quadrilineatus. The patient's condition improved following intravenous voriconazole treatment for 2 weeks, after which he was discharged. Subsequently, the patient was hospitalized six times for pulmonary infections, with the most recent hospitalization being on March 8, 2024. The symptoms improved, and the patient was discharged on March 15, 2024.

Automated classification of group B Streptococcus into different clonal complexes using MALDI-TOF mass spectrometry.

Objectives: To evaluate the performance of Matrix-Assisted Laser Desorption/Ionization Time-of Flight Mass Spectra (MALDI-TOF MS) for automated classification of GBS (Group B Streptococcus) into five major CCs (clonal complexes) during routine GBS identification. Methods: MALDI-TOF MS of 167 GBS strains belonging to five major CCs (CC10, CC12, CC17, CC19, CC23) were grouped into a reference set (n = 67) and a validation set (n = 100) for the creation and evaluation with GBS CCs subtyping main spectrum (MSP) and MSP-M using MALDI BioTyper and ClinProTools. GBS CCs subtyping MSPs-M was generated by resetting the discriminative peaks of GBS CCs subtyping MSP according to the informative peaks from the optimal classification model of five major CCs and the contribution of each peak to the model created by ClinProTools. Results: The PPV for the GBS CCs subtyping MSP-M was greater than the subtyping MSP for CC10 (99.21% vs. 93.65%), but similar for CC12 (79.55% vs. 81.06%), CC17 (93.55% vs. 94.09%), and CC19 (92.59% vs. 95.37%), and lower for CC23 (66.67% vs. 83.33%). Conclusion: MALDI-TOF MS could be a promising tool for the automated categorization of GBS into 5 CCs by both CCs subtyping MSP and MSP-M, GBS CCs subtyping MSP-M is preferred for the accurate prediction of CCs with highly discriminative peaks.

Characterization of Synthetic Peptides by Mass Spectrometry.

In the quality control of synthetic peptides, mass spectroscopy (MS) serves as an optimal method for evaluating authenticity and integrity. Typically, the sequence of a synthetic peptide is already established, thereby directing the focus of analysis towards validating its identity and purity. This chapter outlines straightforward methodologies for conducting MS analyses specifically tailored for synthetic peptides.