Moraxella nonliquefaciens and M. osloensis Are Important Moraxella Species That Cause Ocular Infections

Intratumoral microbiome of adenoid cystic carcinomas and comparison with other head and neck cancers

Adenoid cystic carcinoma (ACC) is a rare, usually slow-growing yet aggressive head and neck malignancy. Despite its clinical significance, our understanding of the cellular evolution and microenvironment in ACC remains limited. We investigated the intratumoral microbiomes of 50 ACC tumor tissues and 33 adjacent normal tissues using 16S rRNA gene sequencing. This allowed us to characterize the bacterial communities within the ACC and explore potential associations between the bacterial community structure, patient clinical characteristics, and tumor molecular features obtained through RNA sequencing. The bacterial composition in the ACC was significantly different from that in adjacent normal salivary tissue, and the ACC exhibited diverse levels of species richness. We identified two main microbial subtypes within the ACC: oral-like and gut-like. Oral-like microbiomes, characterized by increased diversity and abundance of Neisseria, Leptotrichia, Actinomyces, Streptococcus, Rothia, and Veillonella (commonly found in healthy oral cavities), were associated with a less aggressive ACC-II molecular subtype and improved patient outcomes. Notably, we identified the same oral genera in oral cancer and head and neck squamous cell carcinomas. In both cancers, they were part of shared oral communities associated with a more diverse microbiome, less aggressive tumor phenotype, and better survival that reveal the genera as potential pancancer biomarkers for favorable microbiomes in ACC and other head and neck cancers. Conversely, gut-like intratumoral microbiomes, which feature low diversity and colonization by gut mucus layer-degrading species, such as Bacteroides, Akkermansia, Blautia, Bifidobacterium, and Enterococcus, were associated with poorer outcomes. Elevated levels of Bacteroides thetaiotaomicron were independently associated with significantly worse survival and positively correlated with tumor cell biosynthesis of glycan-based cell membrane components.

Association between Moraxella keratitis and advanced glycation end products

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.

A computational quest for identifying potential vaccine candidates against Moraxella lacunata: a multi-pronged approach

Moraxella lacunata is an emerging gram-negative bacterium that is responsible for multiple nosocomial infections. The bacterium is evolving resistance to several antibiotics, and currently, no effective licensed vaccines are available, which warrants the search for new therapeutics. A multi-epitope-based vaccine has been designed for M. lacunata. The complete proteome of M. lacunata contains 10,110 core proteins. Subcellular localization analysis revealed the presence of five proteins in the extracellular matrix, while 19 proteins were predicted to be located in the outer membrane, and 21 proteins were predicted to be located in the periplasmic region. Only two proteins, the type VI secretion system tube protein (Hcp) and the transporter substrate-binding domain-containing protein, were selected for epitope prediction as they fulfilled all the criteria for being potential vaccine candidates. Shortlisted epitopes from the selected proteins were fused together using "GPGPG" linkers to overcome the limitations of single-epitope vaccines. Next, the cholera toxin-B adjuvant was attached to the peptide epitope using an EAAAK linker. Docking analysis was performed to examine the interaction between the vaccine and immune cell receptors, revealing robust intermolecular interactions and a stable binding conformation. Molecular dynamics simulation findings revealed no drastic changes in the binding conformation of complexes during the simulation period. The net binding free energy of vaccine-receptor complexes was estimated using the molecular mechanics energies combined with the Poisson-Boltzmann and surface area continuum solvation (MM-PBSA) method. The reported values were -586.38 kcal/mol, -283.74 kcal/mol, and -296.88 kcal/mol for the TLR-4-vaccine complex, MHC-I-vaccine complex, and MHC-II-vaccine complex, respectively. Furthermore, the molecular mechanics energies combined with the generalized Born and surface area continuum solvation (MM-GBSA) analysis predicted binding free energies of -596.69 kcal/mol, -287.39 kcal/mol, and -298.28 kcal/mol for the TLR-4-vaccine complex, MHC-I-vaccine complex, and MHC-II-vaccine complex, respectively. The theoretical vaccine design proposed in the study could potentially serve as a powerful therapeutic against targeted pathogens, subject to validation through experimental studies.Communicated by Ramaswamy H. Sarma.

Characterisation of a capsular polysaccharide from Moraxella nonliquefaciens CCUG 348T

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.

Dupilumab-associated ocular surface disease is characterized by a shift from Th2/Th17 toward Th1/Th17 inflammation

BACKGROUND

Dupilumab is used for the treatment of atopic dermatitis (AD). Approximately one third of AD patients develop a dupilumab-associated ocular surface disease (DAOSD), of which the pathomechanism is poorly understood. This study aimed at investigating inflammatory markers in tear fluids of patients on dupilumab therapy.

METHODS

Tear fluids were collected from AD patients with DAOSD (ADwDAOSD), AD patients without DAOSD (ADw/oDAOSD), and non-AD patients before and during dupilumab therapy, and analyzed using a specialized proteomic approach quantifying inflammatory markers. The ocular surface microbiome was determined by next generation sequencing technology.

RESULTS

Upon dupilumab therapy, an upregulation of 31 inflammatory markers was observed in DAOSD tear fluids compared to baseline in AD patients. While IL-12B was upregulated in both ADwDAOSD and ADw/oDAOSD groups, the pattern of inflammatory markers significantly differed between groups and over time. In the ADwDAOSD group, a shift from a mixed Th2/Th17 pattern at baseline toward a Th1/Th17 profile under dupilumab was observed. Furthermore, an upregulation of remodeling and fibrosis markers was seen in DAOSD. Semantic map and hierarchical cluster analyses of baseline marker expression revealed four clusters distinguishing between AD and non-AD as well as ADwDAOSD and ADw/oDAOSD patient groups. In a pilot study, dupilumab therapy was associated with a decrease in richness of the ocular surface microbiome.

CONCLUSIONS

DAOSD is characterized by a Th1/Th17 cytokine profile and an upregulation of markers known to promote remodeling and fibrosis. The expression pattern of inflammatory markers in tear fluids at baseline might serve as a prognostic factor for DAOSD.

Moraxella nasibovis sp. nov., Isolated from a Cow with Respiratory Disease

Strain ZY190618T, isolated from the nasal cavity of a cow with respiratory disease, was subjected to taxonomic characterization. Cells of the strain were Gram-stain-negative, aerobic and coccus-shaped. Phylogenetic analysis based on 16 S rRNA gene sequences indicated that the strain belonged to the genus Moraxella with the highest similarity of 98.1% to Moraxella nasovis CCUG 75922T. Phylogenomic analysis based on 810 single-copy genes revealed that the strain was a member of the genus Moraxella and formed a deep and separated clade within the genus. The strain showed the highest orthologous average nucleotide identity (OrthoANI) value of 77.1% with Moraxella ovis CCUG 354T and digital DNA-DNA hybridization (dDDH) value of 24.7% with Moraxella equi NCTC 11012T, respectively. The DNA G + C content was 46.5 mol%. The strain optimally grew at 37 °C (temperature range, 24-42 °C), at pH 8.0 (pH range, 6.0-9.0) and with 1.5% (w/v) NaCl (NaCl range, 0.5-3.0%). The strain contained C18:1 ω9c as the sole predominant fatty acid (> 5 %) and CoQ-8 as the major respiratory quinone. The major polar lipids included phosphatidylglycerol, phosphatidylethanolamine, cardiolipin, monolysocardiolipin and hemibismonoacylglycerophosphate. Based on these data, strain ZY190618T clearly represents a novel species in the genus Moraxella, for which the name Moraxella nasibovis sp. nov. (The type strain ZY190618T = CCUG 75921T = CCTCC AB 2021472T) is proposed.

Ocular Bacterial Infections: A Ten-Year Survey and Review of Causative Organisms Based on the Oklahoma Experience

Ocular infections can be medical emergencies that result in permanent visual impairment or blindness and loss of quality of life. Bacteria are a major cause of ocular infections. Effective treatment of ocular infections requires knowledge of which bacteria are the likely cause of the infection. This survey of ocular bacterial isolates and review of ocular pathogens is based on a survey of a collection of isolates banked over a ten-year span at the Dean McGee Eye Institute in Oklahoma. These findings illustrate the diversity of bacteria isolated from the eye, ranging from common species to rare and unique species. At all sampled sites, staphylococci were the predominant bacteria isolated. Pseudomonads were the most common Gram-negative bacterial isolate, except in vitreous, where Serratia was the most common Gram-negative bacterial isolate. Here, we discuss the range of ocular infections that these species have been documented to cause and treatment options for these infections. Although a highly diverse spectrum of species has been isolated from the eye, the majority of infections are caused by Gram-positive species, and in most infections, empiric treatments are effective.

Moraxella nonliquefaciens-associated infectious scleritis

Infectious scleritis is a rare disease entity with potentially devastating visual sequelae. Here we present the clinical history, work-up and aetiology of an unusual case of infectious scleritis.

Late-Onset Bleb-Related Endophthalmitis Caused by Moraxella nonliquefaciens: A Case Report

Moraxella 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, Moraxella nonliquefaciens 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 M. nonliquefaciens 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 M. nonliquefaciens should be considered in patients who underwent glaucoma filtering surgery with antifibrotic agents.

Moraxella nasicaprae sp. nov., Isolated from a Goat with Respiratory Disease

A novel Gram-stain-negative, aerobic, irregular coccus designated as ZY201224^T, was isolated from the nasal cavity of a goat with respiratory disease in a goat farm, located at Jianshui, Yunnan Province, PR China and its taxonomic position was clarified using a polyphasic approach. The strain grew optimally at 37 °C, at pH 8.0 and in the presence of 1% NaCl. Phylogenetic analysis based on 16S rRNA gene sequence and phylogenomic analysis based on 808 single-copy genes revealed that the strain is affiliated to the genus Moraxella and is distinct from the recognized species of the genus. The 16S rRNA gene sequence similarity analysis indicated that the strain is most closely related to Moraxella caviae CCUG 355^T with sequence similarity of 98.1%. The genomic OrthoANI and digital DNA-DNA hybridization (dDDH) values between the strain and the type strains of Moraxella species were no higher than 74.7% (Moraxella pluranimalium CCUG 54913^T) and 26.0% (Moraxella oblonga NBRC 102422^T), respectively. The G + C content of the complete genome sequence was 43.6 mol%. The strain contained CoQ-8 as the major respiratory quinone, and C_18:1ω9c, C17:1ω8c, C16:0 and summed feature 3 (C_16:1 ω7c and/ or C_16:1ω6c) as the predominant fatty acids (> 5%). The major polar lipids comprised phosphatidylglycerol (PG), cardiolipin (CL), monolysocardiolipin (MLCL), phosphatidylethanolamine (PE) and lysophosphatidylglycerol (LPG). Based on these taxonomic characterizations, strain ZY201224^T represents a novel species of the genus Moraxella, for which the name Moraxella nasicaprae sp. nov. is proposed. The type strain is ZY201224^T (= CCTCC AB 2021474^T = NBRC 115473^T).

The conjunctival microbiome before and after azithromycin mass drug administration for trachoma control in a cohort of Tanzanian children

Background

Trachoma, caused by ocular infection with Chlamydia trachomatis, is a neglected tropical disease that can lead to blinding pathology. Current trachoma control programmes have successfully used mass drug administration (MDA) with azithromycin to clear C. trachomatis infection and reduce transmission, alongside promoting facial cleanliness for better personal hygiene and environmental improvement. In areas of low-trachoma endemicity, the relationship between C. trachomatis infection and trachomatous disease weakens, and non-chlamydial bacteria have been associated with disease signs.

Methods

We enrolled a cohort of children aged 6-10 years from three adjacent trachoma endemic villages in Kilimanjaro and Arusha regions, Northern Tanzania. Children were divided into four clinical groups based on the presence or absence of ocular C. trachomatis infection and clinical signs of trachomatous papillary inflammation (TP). To determine the impact of treatment on the ocular microbiome in these clinical groups, we performed V4-16S rRNA sequencing of conjunctival DNA from children 3-9 months pre-MDA (n = 269) and 3 months post-MDA (n = 79).

Results

Chlamydia trachomatis PCR-negative, no TP children had the highest pre-MDA ocular microbiome alpha diversity, which was reduced in C. trachomatis infected children and further decreased in those with TP. Pre-MDA, Haemophilus and Staphylococcus were associated with C. trachomatis infection with and without concurrent TP, while Helicobacter was increased in those with TP in the absence of current C. trachomatis infection. Post-MDA, none of the studied children had ocular C. trachomatis infection or TP. MDA increased ocular microbiome diversity in all clinical groups, the change was of greater magnitude in children with pre-MDA TP. MDA effectively reduced the prevalence of disease causing pathogenic non-chlamydial bacteria, and promoted restoration of a normal, healthy conjunctival microbiome.

Conclusion

We identified Helicobacter as a non-chlamydial bacterium associated with the clinical signs of TP. Further investigation to determine its relevance in other low-endemicity communities is required. MDA was shown to be effective at clearing C. trachomatis infection and other non-chlamydial ocular pathogens, without any detrimental longitudinal effects on the ocular microbiome. These findings suggest that azithromycin MDA may be valuable in trachoma control even in populations where the relationship between clinical signs of trachoma and the prevalence of current ocular C. trachomatis infection has become dissociated.

Integrated identification of growth pattern and taxon of bacterium in gut microbiota via confocal fluorescence imaging-oriented single-cell sequencing

Despite the fast progress in our understanding of the complex functions of gut microbiota, it is still challenging to directly investigate the in vivo microbial activities and processes on an individual cell basis. To gain knowledge of the indigenous growth/division patterns of the diverse mouse gut bacteria with a relatively high throughput, here, we propose an integrative strategy, which combines the use of fluorescent probe labeling, confocal imaging with single-cell sorting, and sequencing. Mouse gut bacteria sequentially labeled by two fluorescent d-amino acid probes in vivo were first imaged by confocal microscopy to visualize their growth patterns, which can be unveiled by the distribution of the two fluorescence signals on each bacterium. Bacterial cells of interest on the imaging slide were then sorted using a laser ejection equipment, and the collected cells were then sequenced individually to identify their taxa. Our strategy allows integrated acquirement of the growth pattern knowledge of a variety of gut bacteria and their genomic information on a single-cell basis, which should also have great potential in studying many other complex bacterial systems.

Nasopharyngeal metatranscriptome profiles of infants with bronchiolitis and risk of childhood asthma: a multicentre prospective study

BACKGROUND

Bronchiolitis is not only the leading cause of hospitalisation in US infants but also a major risk factor for asthma development. Growing evidence supports clinical heterogeneity within bronchiolitis. Our objectives were to identify metatranscriptome profiles of infant bronchiolitis, and to examine their relationship with the host transcriptome and subsequent asthma development.

METHODS

As part of a multicentre prospective cohort study of infants (age <1 year) hospitalised for bronchiolitis, we integrated virus and nasopharyngeal metatranscriptome (species-level taxonomy and function) data measured at hospitalisation. We applied network-based clustering approaches to identify metatranscriptome profiles. We then examined their association with the host transcriptome at hospitalisation and risk for developing asthma.

RESULTS

We identified five metatranscriptome profiles of bronchiolitis (n=244): profile A: virusRSVmicrobiomecommensals; profile B: virusRSV/RV-Amicrobiome H.influenzae ; profile C: virusRSVmicrobiome S.pneumoniae ; profile D: virusRSVmicrobiome M.nonliquefaciens ; and profile E: virusRSV/RV-Cmicrobiome M.catarrhalis . Compared with profile A, profile B infants were characterised by a high proportion of eczema, Haemophilus influenzae abundance and enriched virulence related to antibiotic resistance. These profile B infants also had upregulated T-helper 17 and downregulated type I interferon pathways (false discovery rate (FDR) <0.005), and significantly higher risk for developing asthma (17.9% versus 38.9%; adjusted OR 2.81, 95% CI 1.11-7.26). Likewise, profile C infants were characterised by a high proportion of parental asthma, Streptococcus pneumoniae dominance, and enriched glycerolipid and glycerophospholipid metabolism of the microbiome. These profile C infants had an upregulated RAGE signalling pathway (FDR <0.005) and higher risk of asthma (17.9% versus 35.6%; adjusted OR 2.49, 95% CI 1.10-5.87).

CONCLUSIONS

Metatranscriptome and clustering analysis identified biologically distinct metatranscriptome profiles that have differential risks of asthma.

Microbial community origin and fate through a rural wastewater treatment plant

Conventional wastewater treatment relies on a complex microbiota; however, much of this community is still to be characterised. To better understand the origin, dynamics and fate of bacteria within a wastewater treatment plant: untreated primary wastewater, activated sludge, and post-treatment effluent were characterised. From 3,163 Exact Sequence Variants (ESVs), 860 were annotated to species-level. In primary wastewater, 28% of ESVs were putative bacterial species previously associated with humans, 14% with animals and 5% as common to the environment. Differential abundance analysis revealed significant relative reductions in ESVs from potentially humans-associated species from primary wastewater to activated sludge, and significant increases in ESVs from species associated with nutrient cycling. Between primary wastewater and effluent, 51% of ESVs from human-associated species did not significantly differ, and species such as Bacteroides massiliensis and Bacteroides dorei increased. These findings illustrate that activated sludge increased extracellular protease and urease-producing species, ammonia and nitrite oxidizers, denitrifiers and specific phosphorus accumulators. Although many human-associated species declined, some persisted in effluent, including strains of potential health or environmental concern. Species-level microbial assessment may be useful for understanding variation in wastewater treatment efficiency as well as for monitoring the release of microbes into surface water and the wider ecosystem. This article is protected by copyright. All rights reserved.

Moraxella nonliquefaciens-Associated Ecthyma Gangrenosum in a Pediatric Patient With Cancer

ABSTRACT

In this brief report, we describe a 16-year-old patient with pre-B-cell acute lymphoblastic leukemia on chemotherapy who presented to the emergency department with a fever and "bruise-like" area on his left forearm. Empiric antibiotic therapy was initiated, and initial tissue biopsy demonstrated findings consistent with ecthyma gangrenosum. On day 4 of admission, initial blood cultures grew Moraxella nonliquefaciens, and targeted antibiotic therapy was initiated and continued for a total of 21 days. The patient was discharged after 6 days of in-patient therapy and made a full recovery. M. nonliquefaciens has been reported to be associated with multiple types of infection, but no cases of M. nonliquefaciens-associated ecthyma gangrenosum were identified in the literature review for this report. Given this unique case and the empiric risks and broad differential associated with cutaneous manifestations in immunocompromised patients, obtaining a skin biopsy for histological examination is imperative for diagnostic workup.

Biological Control of Pest Non-Marine Molluscs: A Pacific Perspective on Risks to Non-Target Organisms

Simple Summary

As malacologists long concerned with conservation of molluscs, we present empirical evidence supporting the proposition that biological control of nonmarine mollusc pests has generally not been demonstrated to be safe and effective, which are the basic measures of success. Yet claims of success often accompany contemporary biological control programs, although without rigorous evaluations. Failed molluscan biocontrol programs include well known classical control efforts that continue to devastate native biodiversity, especially on Pacific islands, as well as more contemporary programs that claim to be safer, with minimal non-target impacts. We do not condemn all biological control programs as ineffective, unsafe, and poorly evaluated, but emphasize the need for programs targeting non-marine molluscs to incorporate the lessons learned from past failures, and to do a better job of defining and measuring success both pre- and post-release of biocontrol agents. Most importantly, we call for the biocontrol community not to rely on entomologists with backgrounds in use of host-specific agents, who yet promote generalist parasites/predators for mollusc control, but to engage more actively with those knowledgeable in molluscan biology, particularly conservation. In doing so, maybe some programs targeting molluscan pests can become safe and effective.

Abstract

Classic biological control of pest non-marine molluscs has a long history of disastrous outcomes, and despite claims to the contrary, few advances have been made to ensure that contemporary biocontrol efforts targeting molluscs are safe and effective. For more than half a century, malacologists have warned of the dangers in applying practices developed in the field of insect biological control, where biocontrol agents are often highly host-specific, to the use of generalist predators and parasites against non-marine mollusc pests. Unfortunately, many of the lessons that should have been learned from these failed biocontrol programs have not been rigorously applied to contemporary efforts. Here, we briefly review the failures of past non-marine mollusc biocontrol efforts in the Pacific islands and their adverse environmental impacts that continue to reverberate across ecosystems. We highlight the fact that none of these past programs has ever been demonstrated to be effective against targeted species, and at least two (the snails Euglandina spp. and the flatworm Platydemus manokwari) are implicated in the extinction of hundreds of snail species endemic to Pacific islands. We also highlight other recent efforts, including the proposed use of sarcophagid flies and nematodes in the genus Phasmarhabditis, that clearly illustrate the false claims that past bad practices are not being repeated. We are not making the claim that biocontrol programs can never be safe and effective. Instead, we hope that in highlighting the need for robust controls, clear and measurable definitions of success, and a broader understanding of ecosystem level interactions within a rigorous scientific framework are all necessary before claims of success can be made by biocontrol advocates. Without such amendments to contemporary biocontrol programs, it will be impossible to avoid repeating the failures of non-marine mollusc biocontrol programs to date.

Applying Concepts of Causal Inference to Infectious Bovine Keratoconjunctivitis

Establishing causation, otherwise known as causal assessment, is a difficult task, made more difficult by the variety of causal assessment frameworks available to consider. In this article, Bradford Hill viewpoints are used to discuss the evidence base for Moraxella bovis and Moraxella bovoculi being component causes of infectious bovine keratoconjunctivitis. Each of the nine Bradford Hill viewpoints are introduced and explained: strength, consistency, specificity, temporality, biologic gradient, plausibility, coherence, experiment, and analogy. Examples of how the viewpoints have been applied for other causal relations are provided, and then the evidence base for M bovis and M bovoculi is discussed.

Speciation and Antibiotic Susceptibilities of Coagulase Negative Staphylococci Isolated from Ocular Infections

Coagulase-negative staphylococci (CoNS) are frequently occurring ocular opportunistic pathogens that are not easily identifiable to the species level. The goal of this study was to speciate CoNS and document antibiotic susceptibilities from cases of endophthalmitis (n = 50), keratitis (n = 50), and conjunctivitis/blepharitis (n = 50) for empiric therapy. All 150 isolates of CoNS were speciated using (1) API Staph (biochemical system), (2) Biolog GEN III Microplates (phenotypic substrate system), and (3) DNA sequencing of the sodA gene. Disk diffusion antibiotic susceptibilities for topical and intravitreal treatment were determined based on serum standards. CoNS identification to the species level by all three methods indicated that S. epidermidis was the predominant species of CoNS isolated from cases of endophthalmitis (84-90%), keratitis (80-86%), and conjunctivitis/blepharitis (62-68%). Identifications indicated different distributions of CoNS species among endophthalmitis (6), keratitis (10), and conjunctivitis/blepharitis (13). Antibiotic susceptibility profiles support empiric treatment of endophthalmitis with vancomycin, and keratitis treatment with cefazolin or vancomycin. There was no clear antibiotic choice for conjunctivitis/blepharitis. S. epidermidis was the most frequently found CoNS ocular pathogen, and infection by other CoNS appears to be less specific and random. Antibiotic resistance does not appear to be a serious problem associated with CoNS.

Integrated omics endotyping of infants with respiratory syncytial virus bronchiolitis and risk of childhood asthma

Respiratory syncytial virus (RSV) bronchiolitis is not only the leading cause of hospitalization in U.S. infants, but also a major risk factor for asthma development. While emerging evidence suggests clinical heterogeneity within RSV bronchiolitis, little is known about its biologically-distinct endotypes. Here, we integrated clinical, virus, airway microbiome (species-level), transcriptome, and metabolome data of 221 infants hospitalized with RSV bronchiolitis in a multicentre prospective cohort study. We identified four biologically- and clinically-meaningful endotypes: A) clinicalclassicmicrobiomeM. nonliquefaciensinflammationIFN-intermediate, B) clinicalatopicmicrobiomeS. pneumoniae/M. catarrhalisinflammationIFN-high, C) clinicalseveremicrobiomemixedinflammationIFN-low, and D) clinicalnon-atopicmicrobiomeM.catarrhalisinflammationIL-6. Particularly, compared with endotype A infants, endotype B infants-who are characterized by a high proportion of IgE sensitization and rhinovirus coinfection, S. pneumoniae/M. catarrhalis codominance, and high IFN-α and -γ response-had a significantly higher risk for developing asthma (9% vs. 38%; OR, 6.00: 95%CI, 2.08-21.9; P = 0.002). Our findings provide an evidence base for the early identification of high-risk children during a critical period of airway development.

Moraxella Bacteremia in Cancer Patients

Moraxella is a gram-negative bacterium part of the Moraxellaceae family. It is a pathogen that is commonly found in the upper respiratory tract of humans. It is a rare cause of community-acquired pneumonia and can be found in immunocompromised individuals, especially those with impaired humoral immunity such as hypogammaglobulinemia and those with lung diseases.

We present three cases of Moraxella infections at the Moffitt Cancer Center between the years 2011 and 2017. We performed a literature review of Moraxella bacteremia in cancer patients and included three patients, two with a history of multiple myeloma and one undergoing radiation therapy for non-small cell lung carcinoma. None of the patients died as a result of the infection. Moraxella infections can result in a range of severity with increasing resistance to antibiotic therapy.

Moraxella nonliquefaciens superinfecting herpes simplex keratitis

INTRODUCTION

Moraxella nonliquefaciens (M. nonliquefaciens) is a low pathogenicity microorganism, which rarely causes ocular infections, unless there is a predisposing factor. The main clinical manifestation of M. nonliquefaciens ocular infections is endophthalmitis and only five cases of corneal infection have been reported. This work shows an update in M. nonliquefaciens corneal infections, and the first reported case of keratitis due to M. nonliquefaciens superinfecting herpes simplex infection.

CASE REPORT

A 84-year old woman with worsening of her herpes simplex keratitis, diagnosed, and treated 2 days before. The slit lamp showed deep paracentral infiltrate and hypopyon. A corneal sample was collected for culture prior to initiation of empiric antibiotic therapy with vancomycin and ceftazidime fortified, oral acyclovir, and cyclopentolate. The strain was identified as M. nonliquefaciens and topical antibiotic therapy was adjusted to ciprofloxacin and ceftazidime. After 2 weeks, the epithelial defect and the infiltrate were resolved and prednisolone was added to the regimen. As the corneal oedema and neovascularization decreased, acyclovir, and prednisolone were slowly tapered. About 4 months later, the visual outcome was 20/50 and the ophthalmic examination showed a clear cornea with a paracentral leucoma.

CONCLUSION

Keratitis due to M. nonliquefaciens is rare and should be suspected in patients with local predisposing factors such as corneal damage or previous corneal infection. Prompt and appropriate combined treatment for the predisposing lesions and the keratitis may improve the prognosis and avoid a more aggressive approach.

Moraxella osloensis infection among adults and children: A pediatric case and literature review

Moraxella osloensis has been reported in the literature as a human pathogen, particularly among immunocompromised adults. In contrast to the adult population, most pediatric cases are among patients with no underlying immunological defect; however, no patient underwent further investigation and no data about the long-term follow-up are available. We report the case of a 2-month-old previously healthy girl infected with Moraxella osloensis. Here, we review case reports and case series of children and adults with Moraxella osloensis infection and compare them with our experience. On the basis of our findings, we recommend further investigations (immunological or other underlying diseases) when a child is found to be infected with these bacteria.

Atypical Microbiological Feature of Infectious Endophthalmitis on Jeju Island: A 10-Year Study at a Single Tertiary Referral Center

Background

To analyze the microbiological causes of infectious endophthalmitis on an isolated island over ten years.

Methods

A retrospective review of the medical records of 49 eyes clinically diagnosed with infectious endophthalmitis between January 2009 and December 2018 was done. The subjects were recruited from a single tertiary referral center on Jeju Island. The baseline characteristics of all subjects were investigated, and a culture examination was performed. The isolated pathogens were analyzed to determine how their microbiological features differed from those in regions with different geographical conditions.

Results

Of the 49 eyes, causative microorganisms were identified in 27 eyes (55.1%). Bacteria were found in 24 cases and fungi in 3 cases. Among the exogenous causes, Staphylococcus species (Staphylococcus aureus, S. epidermidis, and S. hominis) were the most common pathogens (7 cases). Achromobacter xylosoxidans was the second most common causative pathogen (4 cases) followed by Moraxella species (3 cases). The most frequent endogenous origin was due to Klebsiella pneumoniae (6 cases). The subjects were divided into two groups according to the treatment results and analyzed for predisposing factors related to visual outcomes. The presence of diabetes mellitus (P = 0.038) and initial visual acuity (P ≤ 0.001) were significant predisposing factors for visual outcomes.

Conclusion

The causative microorganisms of endogenous endophthalmitis on Jeju Island were not different from those reported previously. However, isolated exogenous microorganisms were different from those reported in other studies from inland areas. A high incidence and atypical clinical features of Achromobacter xylosoxidans and Moraxella in exogenous endophthalmitis were observed, reflective of the distinct climatic features of Jeju Island: high humidity and temperature. Therefore, considering the causative microorganisms of exogenous endophthalmitis, it may be assumed that the causative microorganisms of exogenous endophthalmitis and its clinical manifestations differ according to the region.

Low prevalence of Moraxella catarrhalis in the patients who suffered from conjunctivitis in the southwest of Iran

Objective

Moraxella catarrhalis is a non-motile Gram-negative diplococcus bacterium that contributed to several human infections including conjunctivitis. This study aimed to reveal the prevalence of M. catarrhalis in patients who suffered from conjunctivitis in Ahvaz city, southwest of Iran.

Results

Out of 100 conjunctiva swab specimens, M. catarrhalis was isolated only from one (1%) conjunctivitis cases using the culture method. This strain was isolated from a 34 years old female patient. Also, the results of the polymerase chain reaction (PCR) were in agreement with the culture method, and the specimen that showed positive culture was also positive for specific gene of M. catarrhalis. The remaining 99 specimens did not show positive results with any of the culture and PCR methods.

Bacterial keratitis due to Moraxella nonliquefaciens

Moraxella keratitis can lead to important complications. Moraxella nonliquefaciens(M. nonliquefaciens) has the worst prognosis. Only three cases of corneal infections due to M. nonliquefaciens have been published. The case is presented of a 79-year-old man with bullous keratopathy, recently affected with severe infectious keratitis. Dense, deep, and central stromal infiltrates and hyphaema were detected. After the identification of M. nonliquefaciens in the culture, and given the progression of the condition, the initial empirical treatment was modified to topical ciprofloxacin and ceftazidime in accordance with the antibiogram, combining oral ciprofloxacin and amoxicillin-clavulanate. After 27 days, there was total resolution of the lesion, with central residual leucoma. Keratitis caused by M. nonliquefaciens is rare and must be suspected in elderly patients with local predisposing factors, such as corneal damage or previous eye surgery. Early antibiogram-guided treatment and close monitoring are important to avoid complications and poor compliance.

Delayed-onset bleb-related endophthalmitis caused by Moraxella nonliquefaciens

Bleb-related endophthalmitis is rare and appears months or years after surgery. The causative agents are usually streptococci or gram-negative bacteria. There are few cases in the literature of endophthalmitis caused by Moraxella nonliquefaciens, and most are delayed-onset associated with blebitis after glaucoma filtration surgery. The case is presented of a 90-year-old patient with endophthalmitis in the right eye due to Moraxella nonliquefaciens associated with blebitis 10 years after glaucoma surgery. After treatment, disappearance of blebitis is observed 2weeks later and resolution of vitritis 29 days later, with recovery of vision to previous values (20/200). Endophthalmitis due to Moraxella nonliquefaciens is rare, and is associated with late onset blebitis after glaucoma filtration surgery. Despite the virulence of the clinical symptoms, the visual prognosis is usually favourable.

Occurrence of potentially pathogenic bacteria on shared bicycles

BACKGROUND

Shared bicycles offer the potential to be sources for interindividual bacterial community transfer. However, the overall ecology of the bacterial community persisting on the shared bicycles is still unknown.

METHODS

We used 16S rRNA sequencing techniques in combination with multiple bioinformatic analyses to profile bacterial communities on shared bicycle handles and saddles in selected five locations in a metropolitan area (Chengdu, China). Samples of air around shared bicycles were collected as a control.

RESULTS

We demonstrate that the species richness and diversity of samples from shared bicycles are significantly higher than those of surrounding air samples. Taxonomical composition indicates that community structure of shared bicycle handles and saddles are also different. Additionally, high occurrence of pathogenic or potentially pathogenic genera is found on the surfaces of shared bicycles, including Sphingomonas, Acinetobacter, Staphylococcus, and Cutibacterium. Moreover, PICRUSt (Phylogenetic Investigation of Communities by Reconstruction of Unobserved States) further verifies that bacteria involved in signaling pathways related to human diseases are at significantly higher levels in shared bicycle samples, while bacteria associated with environmental information processing pathways are at significantly higher levels in the air samples.

CONCLUSION

Our results reveal the profiles of bacterial communities on shared bicycles, and suggest that potentially pathogenic bacteria may impair human health through shared bicycles, especially in susceptible individuals. Notably, this investigation will prompt the public to pay more attention to the management of bicycle sharing programs worldwide, and it also provides research basis for the government to formulate corresponding public health policies.

Endophytic Bacteria Potentially Promote Plant Growth by Synthesizing Different Metabolites and their Phenotypic/Physiological Profiles in the Biolog GEN III MicroPlateTM Test

Endophytic bacteria, as the most promising components of effective, biofertilizers biostimulating and biocontrol preparations, should be very intensively obtained from various plants and studied in terms of the conditions determining the potential ability to promote plant growth. For this reason, endophytic bacteria have been isolated from both stems and roots of up to six systematically distant species of vascular plants: one species belonging to the seedless vascular plants (Monilophyta), and five seed plants (Spermatophyta). The 23 isolated strains represented nine genera: Delftia, Stenotrophomonas, Rhizobium, Brevundimonas, Variovorax, Achromobacter, Novosphingobium, Comamonas and Collimonas, notably which were closely related—belonging to the phylum Proteobacteria. Stenotrophomonas sp. strains showed the greatest ability to synthesize indole-3-acetic acid (IAA)-like compounds, while Achromobacter sp. strains produced the highest levels of siderophores. The presence of the nifH gene and nitrogen binding activity was demonstrated for 95% of the strains tested. Stenotrophomonas maltophila (ES2 strain) showed the highest metabolic activity based on Biolog GEN III test. The ability to solubilize phosphate was determined only for three tested strains from genus: Delftia, Rhizobium and Novosphingobium. The presented work demonstrated that the metabolic and phenotypic properties of plant growth-promoting endophytes are correlated with the genus of bacteria and are not correlated with the host plant species or part of plant (stem, root).