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Scientific Reports Apr 2024Diabetes mellitus is recognized as a major predisposing factor for Moraxella keratitis. However, how diabetes mellitus contributes to Moraxella keratitis remains...
Diabetes mellitus is recognized as a major predisposing factor for Moraxella keratitis. However, how diabetes mellitus contributes to Moraxella keratitis remains unclear. In this study, we examined Moraxella keratitis; based on the findings, we investigated the impact of advanced glycation end products (AGEs) deposition in the cornea of individuals with diabetic mellitus on the adhesion of Moraxella isolates to the cornea. A retrospective analysis of 27 culture-proven cases of Moraxella keratitis at Ehime University Hospital (March 2006 to February 2022) was performed. Moraxella isolates were identified using matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Among the patients, 30.4% had diabetes mellitus and 22.2% had the predominant ocular condition of using steroid eye drops. The species identified were Moraxella nonliquefaciens in 59.3% and Moraxella lacunata in 40.7% of patients. To investigate the underlying mechanisms, we assessed the effects of M. nonliquefaciens adherence to simian virus 40-immortalized human corneal epithelial cells (HCECs) with or without AGEs. The results demonstrated the number of M. nonliquefaciens adhering to HCECs was significantly increased by adding AGEs compared with that in controls (p < 0.01). Furthermore, in the corneas of streptozotocin-induced diabetic C57BL/6 mice treated with or without pyridoxamine, an AGE inhibitor, the number of M. nonliquefaciens adhering to the corneas of diabetic mice was significantly reduced by pyridoxamine treatment (p < 0.05). In conclusion, the development of Moraxella keratitis may be significantly influenced by the deposition of AGEs on the corneal epithelium of patients with diabetes mellitus.
Topics: Humans; Animals; Mice; Retrospective Studies; Diabetes Mellitus, Experimental; Pyridoxamine; Mice, Inbred C57BL; Keratitis; Moraxella; Cornea; Glycation End Products, Advanced
PubMed: 38580798
DOI: 10.1038/s41598-024-58659-7 -
Carbohydrate Research Apr 2024Moraxella nonliquefaciens is a commensal of the human upper respiratory tract (URT) but on rare occasions is recovered in cases of ocular, septic and pulmonary...
Moraxella nonliquefaciens is a commensal of the human upper respiratory tract (URT) but on rare occasions is recovered in cases of ocular, septic and pulmonary infections. Hence there is interest in the pathogenic determinants of M. nonliquefaciens, of which outer membrane (OM) structures such as fimbriae and two capsular polysaccharide (CPS) structures, →3)-β-D-GalpNAc-(1→5)-β-Kdop-(2→ and →8)-α-NeuAc-(2→, have been reported in the literature. To further characterise its surface virulence factors, we isolated a novel CPS from M. nonliquefaciens type strain CCUG 348T. This structure was elucidated using NMR data obtained from CPS samples that were subjected to various degrees of mild acid hydrolysis. Together with GLC-MS data, the structure was resolved as a linear polymer composed of two GalfNAc residues consecutively added to Kdo, →3)-β-D-GalfNAc-(1→3)-α-D-GalfNAc-(1→5)-α-(8-OAc)Kdop-(2→. Supporting evidence for this material being CPS was drawn from the proposed CPS biosynthetic locus which encoded a potential GalfNAc transferase, a UDP-GalpNAc mutase for UDP-GalfNAc production and a putative CPS polymerase with predicted GalfNAc and Kdo transferase domains. This study describes a unique CPS composition reported in Moraxella spp. and offers genetic insights into the synthesis and expression of GalfNAc residues, which are rare in bacterial OM glycans.
Topics: Humans; Polysaccharides; Moraxella; Transferases; Uridine Diphosphate; Bacterial Capsules; Polysaccharides, Bacterial
PubMed: 38507941
DOI: 10.1016/j.carres.2024.109095 -
Frontiers in Immunology 2024Bronchiolitis, a viral lower respiratory infection, is the leading cause of infant hospitalization, which is associated with an increased risk for developing asthma...
Bronchiolitis, a viral lower respiratory infection, is the leading cause of infant hospitalization, which is associated with an increased risk for developing asthma later in life. Bronchiolitis can be caused by several respiratory viruses, such as respiratory syncytial virus (RSV), rhinovirus (RV), and others. It can also be caused by a solo infection (e.g., RSV- or RV-only bronchiolitis) or co-infection with two or more viruses. Studies have shown viral etiology-related differences between RSV- and RV-only bronchiolitis in the immune response, human microRNA (miRNA) profiles, and dominance of certain airway microbiome constituents. Here, we identified bacterial small RNAs (sRNAs), the prokaryotic equivalent to eukaryotic miRNAs, that differ between infants of the 35 Multicenter Airway Research Collaboration (MARC-35) cohort with RSV- versus RV-only bronchiolitis. We first derived reference sRNA datasets from cultures of four bacteria known to be associated with bronchiolitis (i.e., , , , and ). Using these reference sRNA datasets, we found several sRNAs associated with RSV- and RV-only bronchiolitis in our human nasal RNA-Seq MARC-35 data. We also determined potential human transcript targets of the bacterial sRNAs and compared expression of the sRNAs between RSV- and RV-only cases. sRNAs are known to downregulate their mRNA target, we found that, compared to those associated with RV-only bronchiolitis, sRNAs associated with RSV-only bronchiolitis may relatively activate the IL-6 and IL-8 pathways and relatively inhibit the IL-17A pathway. These data support that bacteria may be contributing to inflammation differences seen in RSV- and RV-only bronchiolitis, and for the first time indicate that the potential mechanism in doing so may be through bacterial sRNAs.
Topics: Infant; Humans; Rhinovirus; RNA, Bacterial; Bronchiolitis; Respiratory Syncytial Virus, Human; Respiratory Syncytial Virus Infections; Viruses; MicroRNAs; Enterovirus Infections; Immunity
PubMed: 38410509
DOI: 10.3389/fimmu.2024.1330991 -
JPMA. the Journal of the Pakistan... Dec 2023To detect mutation in cases having haemoglobin A2 level >7% on high performance liquid chromatography.
OBJECTIVE
To detect mutation in cases having haemoglobin A2 level >7% on high performance liquid chromatography.
METHODS
The cross-sectional, descriptive study was conducted from July 2017 to December 2018 at the Department of Haematology and Human Genetics and Molecular Biology, University of Health Sciences, Lahore, Pakistan, and comprised patients of either gender with haemoglobin A2 ≥7%. The samples were collected from different cities of Punjab in collaboration with the Punjab Thalassemia Prevention Programme, Lahore. The samples were subjected to complete blood count and high performance liquid chromatography using automated haematology analysers and variant-II beta thalassemia short programme, respectively. To analyse haemoglobin E mutations at the molecular level, polymerase chain reaction-restriction fragment length polymorphism (PCR_RFLP) was performed using a type IIS restriction endonuclease known as Mnl1 (derived from Moraxella nonliquefaciens) to cleave DNA at specific sites and the results were further confirmed on randomly selected samples using Sanger sequencing. Data was analysed using SPSS 25.
RESULTS
Of the 39 patients, 15(38.5%) were males and 24(61.5%) were females. The overall median age was 14 (23) years. There were 29 (74.4%) patients with thalassemia family history, and 22(56.4%) had a positive family history of transfusion related to thalassemia, while no patient had a family history of iron therapy. The median haemoglobin A, haemoglobin A2 and haemoglobin F levels were 72.2 (65.2-79.1) %, 26.6 (19.1-34.0) % and 0.9 (-0.8-2.6) %, respectively. After molecular investigation, HbAE mutation was found in 23(59%) patients, while wild type HbAA genotype was found in 16(41%). The heterozygous HbE mutation was present in 23(59%) patients.
CONCLUSIONS
Frequently missed/undiagnosed cases of haemoglobin E that co-elute with haemoglobin A2 in the same high performance liquid chromatography window were detected among those with haemoglobin A2 ≥7%.
Topics: Male; Female; Humans; Adolescent; Hemoglobin E; Hemoglobin A2; Cross-Sectional Studies; Genotype; beta-Thalassemia; Thalassemia; Mutation
PubMed: 38083912
DOI: 10.47391/JPMA.7138 -
Antibiotics (Basel, Switzerland) Mar 2023species are Gram-negative coccobacilli that typically colonize the flora of the human upper respiratory tract and have low pathogenic potential. There are limited case...
species are Gram-negative coccobacilli that typically colonize the flora of the human upper respiratory tract and have low pathogenic potential. There are limited case reports implicating the organisms as the cause of endocarditis, bacteremia, septic arthritis, ocular infection, and meningitis. In cases of keratitis and conjunctivitis, is not commonly isolated from the ocular surface. We present a case of a diabetic patient who developed late-onset bleb-related endophthalmitis caused by 4 years after glaucoma filtering surgery. Within one day, the patient presented with an acutely fulminant course with sudden visual loss, redness, and ocular pain. Appropriate antibiotic treatment and early vitrectomy resulted in a favorable final visual acuity of 20/100, which was his vision prior to infection. The use of Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass spectrometry (MALDI-TOF MS) enabled the rapid identification of the organism. Endophthalmitis caused by should be considered in patients who underwent glaucoma filtering surgery with antifibrotic agents.
PubMed: 36978474
DOI: 10.3390/antibiotics12030607 -
Scientific Reports Nov 2022Nasal decolonization procedures against the opportunistic pathogen Staphylococcus aureus rely on topical antimicrobial drug usage, whose impact on the nasal microbiota...
Nasal decolonization procedures against the opportunistic pathogen Staphylococcus aureus rely on topical antimicrobial drug usage, whose impact on the nasal microbiota is poorly understood. We examined this impact in healthy S. aureus carriers and noncarriers. This is a prospective interventional cohort study of 8 S. aureus carriers and 8 noncarriers treated with nasal mupirocin and chlorhexidine baths. Sequential nasal swabs were taken over 6 months. S. aureus was detected by quantitative culture and genotyped using spa typing. RNA-based 16S species-level metabarcoding was used to assess the living microbial diversity. The species Dolosigranulum pigrum, Moraxella nonliquefaciens and Corynebacterium propinquum correlated negatively with S. aureus carriage. Mupirocin treatment effectively eliminated S. aureus, D. pigrum and M. nonliquefaciens, but not corynebacteria. S. aureus recolonization in carriers occurred more rapidly than recolonization by the dominant species in noncarriers (median 3 vs. 6 months, respectively). Most recolonizing S. aureus isolates had the same spa type as the initial isolate. The impact of mupirocin-chlorhexidine treatment on the nasal microbiota was still detectable after 6 months. S. aureus recolonization predated microbiota recovery, emphasizing the strong adaptation of this pathogen to the nasal niche and the transient efficacy of the decolonization procedure.
Topics: Humans; Mupirocin; Staphylococcus aureus; Chlorhexidine; Prospective Studies; Cohort Studies; Carrier State; Staphylococcal Infections; Microbiota
PubMed: 36396730
DOI: 10.1038/s41598-022-21453-4 -
Revista Argentina de Microbiologia 2023This is the first study of the genetic diversity of Moraxella spp. Isolates were detected in an Eye Hospital in the City of Buenos Aires. Due to the high frequency of...
This is the first study of the genetic diversity of Moraxella spp. Isolates were detected in an Eye Hospital in the City of Buenos Aires. Due to the high frequency of Moraxella spp. observed in corneal abscesses, we decided to validate their identification at the species level, determine their drug susceptibility and perform molecular subtyping. Seventeen (17) isolates obtained from corneal abscesses were evaluated. The identification was carried out using a combination of biochemical tests and MALDI-TOF mass spectrometry. Of these isolates, 88.2% were identified as Moraxella lacunata, and 11.8% as Moraxella nonliquefaciens. Molecular subtyping was performed using the pulsed-field gel electrophoresis (PFGE) technique. All isolates were typable and thirteen digestion patterns were identified. Based on the obtained results, the PFGE technique using the SmaI enzyme can be used for epidemiological studies of strains of these species.
Topics: Humans; Abscess; Moraxella; Electrophoresis, Gel, Pulsed-Field; Genetic Variation
PubMed: 35915013
DOI: 10.1016/j.ram.2022.03.004 -
IDCases 2021A 2-year-old, previously healthy, male presented with an insidious history of intermittent left knee pain and edema who had been evaluated in the emergency department on...
A 2-year-old, previously healthy, male presented with an insidious history of intermittent left knee pain and edema who had been evaluated in the emergency department on multiple occasions with unremarkable imaging and normal laboratory results. On the day of presentation, he had mild edema of the left knee and inability to bear weight. Synovial fluid analysis showed an elevated white cell count with neutrophil predominance and mildly elevated inflammatory markers, consistent with septic arthritis. He underwent knee arthrotomy with irrigation and debridement and was initiated on broad spectrum antibiotics. Cultures were negative, polymerase chain reaction for MRSA and were negative. He was started on a fifth-generation cephalosporin with resolution of symptoms, marked clinical improvement and normalization of inflammatory markers. The identification of the etiologic agent was possible due to detection of bacterial 16S rRNA gene amplification by PCR for in the synovial fluid. He completed a course of 3 weeks of parenteral antibiotics at home with full recovery.
PubMed: 34026535
DOI: 10.1016/j.idcr.2021.e01145 -
Japanese Journal of Infectious Diseases Sep 2021To improve our current understanding of normal flora in children, we investigated bacterial isolates from the pharynx and nasopharynx of 173 and 233 healthy children,...
To improve our current understanding of normal flora in children, we investigated bacterial isolates from the pharynx and nasopharynx of 173 and 233 healthy children, respectively. The bacterial isolation rates were compared among three age groups: infants (<1 year), toddlers (1-5 years), and school-aged children (6-15 years). Gram-positive cocci were the predominant bacteria in the pharynx (Streptococcus mitis/oralis, 87.3%; Streptococcus salivarius, 54.3%; Rothia mucilaginosa, 41.6%; Staphylococcus aureus, 39.3%). Among infants, S. salivarius and Neisseria subflava, which are related to the development of teeth, were significantly lower than in the other age groups (P <0.0001, S. salivarius; P <0.01, N. subflava). With the exception of Corynebacterium pseudodiphtheriticum (44.2%, gram-positive rods), gram-negative rods largely predominated the nasopharynx (Moraxella catarrhalis, 32.1%; Moraxella nonliquefaciens, 28.3%). Among toddlers, M. catarrhalis and Streptococcus pneumoniae, which are the most common pathogens in acute otitis media, were significantly higher than in the infant group (P <0.05). Among the bacterial species implicated in pediatric respiratory infections, Streptococcus pyogenes was isolated in 3.5% of the pharyngeal samples. S. pneumoniae and Haemophilus influenzae were isolated in 22.3% and 17.2% of the nasopharyngeal samples, respectively. In conclusion, the normal flora of the respiratory tract differs not only by the sampling site but also by the age group.
Topics: Adolescent; Bacterial Infections; Child; Child, Preschool; Female; Gram-Negative Aerobic Rods and Cocci; Gram-Positive Cocci; Haemophilus influenzae; Humans; Infant; Male; Moraxella; Moraxella catarrhalis; Nasopharynx; Pharynx; Pneumococcal Infections; Streptococcus pneumoniae; Streptococcus pyogenes
PubMed: 33642434
DOI: 10.7883/yoken.JJID.2020.824 -
Scientific Reports Nov 2020Nasopharyngeal colonization by bacteria is a prerequisite for progression to respiratory disease and an important source of horizontal spread within communities. We...
Nasopharyngeal colonization by bacteria is a prerequisite for progression to respiratory disease and an important source of horizontal spread within communities. We aimed to perform quantitative analysis of the bacterial cells and reveal the microbiota of the nasal discharge in children at the species level based on highly accurate 16S rRNA gene sequencing. This study enrolled 40 pediatric patients with rhinorrhea. The bacterial cells in the nasal discharge were counted by epifluorescence microscopic analysis. The microbiota was analyzed by using the 16S rRNA gene clone library sequencing method. We demonstrated that a high abundance (median 2.2 × 10 cells/mL) of bacteria was contained in the nasal discharge of children. Of the 40 samples, 37 (92.5%) were dominated by OTUs corresponding to Haemophilus aegyptius/influenzae, Moraxella catarrhalis/nonliquefaciens, or Streptococcus pneumoniae. These samples showed higher cell abundance and lower alpha diversity than the remaining three samples in which the other bacteria coexisted. In addition, 12 sequences with low homology to type strains were considered as previously unknown bacterial lineages. In conclusion, the nasal discharge of most young children contains a large amount of respiratory pathogens and several unknown bacteria, which could not only cause endogenous infection but also be a source of transmission to others.
Topics: Child; Child, Preschool; Female; Haemophilus; Haemophilus influenzae; Humans; Infant; Male; Moraxella; Nasopharynx; RNA, Ribosomal, 16S; Respiratory Tract Infections; Rhinorrhea; Sequence Analysis, RNA; Streptococcus pneumoniae
PubMed: 33214657
DOI: 10.1038/s41598-020-77271-z