Isolation and identification of a high-efficiency hexavalent uranium adsorption strain and preliminary study of the influencing factors and adsorption mechanism

In this study, a bacterial strain Chryseobacterium bernardetii WK-3 was isolated from the rhizosphere soil of a uranium tailings in Southern China. It can efficiently adsorb hexavalent uranium with an adsorption ratio of 92.3%. The influence of different environmental conditions on the adsorption ratio of Chryseobacterium bernardetii strain WK-3 was investigated, and the adsorption mechanism was preliminarily discussed by scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS). The results showed that the optimal adsorption conditions for U(VI) by Chryseobacterium bernardetii strain WK-3 were pH = 5, temperature 30 ℃, NaCl concentration 1%, and inoculation volume 10%. When the initial concentration of U was 50 ~ 150 mg/L, the adsorption capacity of Chryseobacterium bernardetii strain WK-3 to U(VI) reached the maximum and maintained the equilibrium at 44 h. SEM-EDS results showed that phosphorus in cells participates in the interaction of uranyl ions, which may indicate that phosphate was produced during cell metabolism and was further combined to form U(VI)-phosphate minerals. In summary, Chryseobacterium bernardetii strain WK-3 would be a promising alternative for environmental uranium contamination remediation.

nov

Strain Ran72T, a novel Gram-stain-negative, obligately aerobic, non-motile, and rod-shaped bacterium, was isolated from the faeces of the rhinoceros species Ceratotherium simum. The novel bacterial strain grew optimally in Reasoner's 2A medium under the following conditions: 0 % (w/v) NaCl, pH 7.5, and 30 °C. Based on phylogenetic analysis using 16S rRNA gene sequencing, strain Ran72T was found to be most closely related to Chryseobacterium faecale F4T (98.4 %), Kaistella soli DKR-2T (98.0 %), and Kaistella haifensis H38T (97.4 %). A comprehensive genome-level comparison between strain Ran72T with C. faecale F4T, K. soli DKR-2T, and K. haifensis H38T revealed average nucleotide identity, digital DNA-DNA hybridization, and average amino acid identity values of ≤74.9, ≤19.3, and ≤78.7 %, respectively. The major fatty acids were anteiso-C15 : 0 (22.3 %), with MK-6 being the predominant respiratory quinone. The major polar lipids of strain Ran72T were phosphatidylethanolamine, four unidentified aminolipids, and two unidentified lipids. Based on our chemotaxonomic, genotypic, and phenotype characterizations, strain Ran72T was identified as representing a novel species in the genus Kaistella, for which the name Kaistella rhinocerotis sp. nov. is proposed, with the type strain Ran72T (=KACC 23136T=JCM 36038T). Based on the outcomes of our phylogenomic study, Chryseobacterium faecale should be reclassified under the genus Kaistella as Kaistella faecalis comb. nov.

nov., a bacterium possessing metallophore activity towards rare earth elements

A polyphasic taxonomic study was carried out on strain ES2T, isolated from sediment of a wetland created to remediate acid drainage from a coal mine. The rod-shaped bacterium formed yellow/orange pigmented colonies and produced the pigment flexirubin. The 16S rRNA gene sequence results assigned the strain to Chryseobacterium, with 98.9 and 98.3 % similarity to Chryseobacterium vietnamense and Chryseobacterium cucumeris, respectively. Computation of the average nucleotide identity and digital DNA-DNA hybridization values with the closest phylogenetic neighbours of ES2T revealed genetic differences at the species level, which were further substantiated by differences in several physiological characteristics. The dominant fatty acids of strain ES2T were iso-C15 : 0, iso-C17 : 1 ω9c, iso C17 : 0 3-OH, and iso-C15 : 0 2-OH. The DNA G+C content was 35.5 mol%. The major polar lipid was phosphatidylethanolamine while menaquinone-6 was the only menaquinone found. This bacterium has been previously shown to possess metallophore activity towards rare earth elements, and based on genome sequencing, possesses all required genes for siderophore production/activity, possibly identifying the source of this unique ability. On the basis of the results obtained here, this bacterium is assigned to the genus Chryseobacterium as representing a new species with the name Chryseobacterium metallicongregator sp. nov., type strain ES2T (=NRRL B-65679T=KCTC 102120T).

isolated from a diabetic, non-catheterized patient

Chryseobacterium demonstrates a diverse environmental presence and a significant pathogenic potential across various ecosystems. This clinical case showcases a rare instance of bacterial infection in a 75-year-old male with untreated diabetes and recurrent urinary tract infections (UTIs). The patient presented symptoms of abdominal pain, burning urination, fever, and an elevated eosinophil count. A subsequent urine culture identified a Chryseobacterium-related bacterium as the causative agent, exhibiting sensitivity to piperacillin/tazobactam, trimethoprim/sulfamethoxazole, and nitrofurantoin, which led to successful treatment using oral nitrofurantoin. Analysis of the 16S rRNA gene sequence of APV-1T revealed a close relationship of 98.2% similarity to Chryseobacterium gambrini strain 5-1St1aT (AM232810). Furthermore, comparative genome analysis, incorporating Average Nucleotide Identity (ANI), Digital DNA-DNA Hybridization (dDDH) values, and comprehensive phylogenetic assessments utilizing 16S rRNA gene sequences, core genes, and amino acid sequences of core proteins, highlighted the unique phylogenetic positioning of APV-1T within the Chryseobacterium genus. Distinct carbon utilization and assimilation patterns, along with major fatty acid content, set APV-1T apart from C. gambrini strain 5-1St1aT. These findings, encompassing phenotypic, genotypic, and chemotaxonomic characteristics, strongly support the proposal of a novel species named Chryseobacterium urinae sp. nov., with APV-1T designated as the type strain (= MCC 50690 = JCM 36476). Despite its successful treatment, the strain displayed resistance to multiple antibiotics. Genomic analysis further unveiled core-conserved genes, strain-specific clusters, and genes associated with antibiotic resistance and virulence. This report underscores the vital importance of elucidating susceptibility patterns of rare pathogens like Chryseobacterium, particularly in immunocompromised individuals. It advocates for further analyses to understand the functional significance of identified genes and their implications in treatment and pathogenesis.

strain PMSZPI cells for efficient uranium removal

Uranium (U) contamination is hazardous to human health and the environment owing to its radiotoxicity and chemical toxicity and needs immediate attention. In this study, the immobilized biomass of Chryseobacterium sp. strain PMSZPI isolated from U enriched site, was investigated for U(VI) biomineralization in batch and column set-up. Under batch mode, the fresh or lyophilized cells successfully entrapped in calcium alginate beads demonstrated effectual U precipitation under acid and alkaline conditions. The maximum removal was detected at pH 7 wherein ∼98-99% of uranium was precipitated from 1 mM uranyl carbonate solution loading ∼350 mg U/g of biomass within 24 h in the presence of organic phosphate substrate. The resulting uranyl phosphate precipitates within immobilized biomass loaded beads were observed by SEM-EDX and TEM while the formation of U biomineral was confirmed by FTIR and XRD. Retention of phosphatase activity without any loss of uranium precipitation ability was observed for alginate beads with lyophilized biomass stored for 90 d at 4 °C. Continuous flow through experiment with PMSZPI biomass immobilized in polyacrylamide gel exhibited U loading of 0.8 g U/g of biomass at pH 7 using 1 l of 1 mM uranyl solution. This investigation established the feasibility for the application of immobilized PMSZPI biomass for field studies. ENVIRONMENTAL IMPLICATION: Uranium contamination is currently a serious environmental concern owing to anthropogenic activities and needs immediate attention. We have developed here a biotechnological method for successful uranium removal using immobilized cells of a uranium tolerant environmental bacterium, Chryseobacterium sp. strain PMSZPI isolated from U ore deposit via phosphatase enzyme mediated uranium precipitation. The ability of immobilized PMSZPI cells to precipitate U(VI) as long-term stable U phosphates under environmental conditions relevant for contaminated waters containing high concentrations of U that exerts toxicity for biological systems is explored here. The long term stability of the immobilized biomass without compromising its U removal capacity shows the relevance of the bioremediation strategy for uranium contamination proposed in this work.

The integrative and conjugative element ICECiPOL15 mediates horizontal transfer of β-lactam resistance gene in Chryseobacterium indoltheticum POL15

OBJECTIVES

The dissemination of antibiotic resistance genes (ARGs) from the environment, including agricultural sources, is of increasing concern. In this study, we examined the antibiotic resistance profile and genomic sequence of a strain of Chryseobacterium indoltheticum obtained from an agricultural location.

METHODS

The multidrug-resistant bacterial strain POL15 was isolated from the wastewater of a livestock farm in China. Whole-genome sequencing was performed followed by bioinformatics analyses to identify integrative and conjugative elements (ICEs) and ARGs. Mating assays were performed to analyse ICE transferability.

RESULTS

Whole-genome sequencing and annotation showed that the genome of POL15 encodes ARGs. Additionally, an ICE named ICECiPOL15, which carries a class C β-lactamase-encoding gene blaAQU, was identified in the POL15 genome. Genes encoding an integrase, an excisionase, a relaxase, a type IV coupling protein and conjugative transposon proteins involved in a type IV secretion system were also identified in ICECiPOL15. Sequence alignment revealed that ICECiPOL15 might have evolved from other Chryseobacterium species. The horizontal transferability of ICECiPOL15 was demonstrated by mating experiments between C. indoltheticum POL15 and Escherichia coli DL21.

CONCLUSIONS

This study represents the first characterization of a mobilizable antibiotic resistance ICE in a species of C. indoltheticum and provides evidence that C. indoltheticum strains could be important reservoirs and vehicles for ARGs on livestock farms.

Phenotypic and genomic characterization of a non-pathogenic Epilithonimonas ginsengisoli isolated from diseased farmed rainbow trout (Oncorhynchus mykiss) in Chile

Flavobacterial infection associated with diseased fish is caused by multiple bacterial species within the family Flavobacteriaceae. In the present study, the Chilean isolate FP99, from the gills of a diseased, farmed rainbow trout (Oncorhynchus mykiss), was characterized using phenotypic and genomic analyses. Additionally assessed was pathogenic activity. Phylogenetic analysis based on 16S rRNA gene sequencing confirmed that isolate FP99 belonged to the genus Epilithonimonas, an average nucleotide identity value of 100% was detected with the Chilean isolate identified as Epilithonimonas sp. FP211-J200. In silico genome analysis, mechanisms for toxins production, and superantigens, adhesion, or other genes associated with virulence were not detected. However, genes encoding proteins for antibiotic resistance were found, including the chrA gene and the nucleotide sequence that encodes for multiple antibiotic resistance MarC proteins. Furthermore, the blaESP-1 gene (87.85% aminoacidic sequence identity), encoding an extended-spectrum subclass B3 metallo-β-lactamase and conferring carbapenem-hydrolysing activity, and the tet(X) gene, which encodes a monooxygenase that catalyses the degradation of tetracycline-class antimicrobials were carried by this isolate. Phenotyping analyses also supported assignment as E. ginsengisoli. Challenge trials against healthy rainbow trout resulted in no observed pathogenic effect. Our findings identify for the first time the species E. ginsengisoli as associated with fish farming, suggesting that this isolate may be a component of the microbiota of the freshwater system. Notwithstanding, poor environmental conditions and any stressors associated with aquaculture situations or lesions caused by other pathogenic bacteria, such as F. psychrophilum, could favour the entry of E. ginsengisoli into rainbow trout.

nov., a keratinolytic bacterium isolated from a freshwater river

A Gram-stain-negative, aerobic, rod-shaped bacterial strain, designated MMS21-Ot14T, was isolated from a freshwater river, and shown to represent a novel species of the genus Chryseobacterium on the basis of the results from a polyphasic approach. The 16S rRNA gene sequence analysis revealed that MMS21-Ot14T represented a member of the genus Chryseobacterium of the family Weeksellaceae and was closely related to Chryseobacterium hagamense RHA2-9T (97.52 % sequence similarity), Chryseobacterium gwangjuense THG A18T (97.46 %) and Chryseobacterium gregarium P 461/12T (97.27 %). The optimal growth of MMS21-Ot14T occurred at 25-30 °C, pH 6.0-7.0 and in the absence of NaCl. MMS21-Ot14T was capable of hydrolysing casein, starch, DNA, Tween 20 and tyrosine. The strain also showed keratinolytic activity with keratin azure and decolourising activity with remazol brilliant blue R (RBBR), which indicated potential ability to degrade keratin and lignin. The main polar lipids of MMS21-Ot14T were phosphatidylethanolamine, unidentified aminophospholipids, unidentified aminolipids, an unidentified phospholipid and several unidentified lipids. The predominant fatty acids of MMS21-Ot14T were iso-C15 : 0 and iso-C17 : 0 3-OH, and the major isoprenoid quinone was menaquinone 6 (MK-6). The whole genome of MMS21-Ot14T was 5 062 016 bp in length with a DNA G+C content of 37.7 %. The average nucleotide identity and digital DNA-DNA hybridisation values between MMS21-Ot14T and phylogenetically related members of the genus Chryseobacterium were well below the threshold values for species delineation. It is evident from the results of this study that MMS21-Ot14T should be classified as representing a novel species of the genus Chryseobacterium, for which the name Chryseobacterium fluminis sp. nov. (type strain, MMS21-Ot14T = KCTC 92255T = LMG 32529T) is proposed.

Elizabethkingia meningoseptica Outbreak in NICU: An Observational Study on a Debilitating Neuroinfection in Neonates

BACKGROUND

Elizabethkingia meningoseptica is an emerging nosocomial pathogen implicated in neonatal sepsis with high mortality and morbidities. However, there is very limited data regarding the characteristics as well as outcomes following this infection, particularly in developing countries.

METHODS

We conducted a retrospective observational study of all infants with culture-positive Elizabethkingia sepsis as part of an outbreak, to study their clinical and epidemiological characteristics, as well as their antimicrobial susceptibility patterns, using a structured proforma from the neonatal intensive care unit database. Analysis was done using descriptive statistics and predictors of mortality and hydrocephalus were also identified.

RESULTS

Of the 21 neonates enrolled, 9 (42.9%) were male, with a mean gestational age and birth weight of 31.7 ± 3.4 weeks and 1320 ± 364 g, respectively. The median (interquartile range) age of onset of illness was 7 (5-12) days. The overall mortality rate was 23.8%, and among survivors, 50% had neurologic complications requiring intervention. Vancomycin and ciprofloxacin were the most used antibiotics for treatment in our series, with a median duration of 26 (17-38) days. On univariate analysis, shock at presentation was significantly associated with increased mortality (P = 0.04) while, seizures (P = 0.04) and elevated cerebrospinal fluid protein levels (P = 0 .01) at onset of illness predicted progressive hydrocephalus in surviving neonates.

CONCLUSION

E. meningoseptica sepsis is associated with high morbidity and mortality. Early diagnosis and prompt initiation of appropriate antibiotics are critical for improving survival and neurodevelopmental outcomes. Though isolation of the organism by environmental surveillance is always not possible, with proper infection control measures, the infection can be controlled.

Probability of outbreaks and cross-border dissemination of the emerging pathogen: a genomic survey of Elizabethkingia meningoseptica

IMPORTANCE

Elizabethkingia meningoseptica is an emerging infectious agent associated with life-threatening infections in immunocompromised individuals. However, there are limited data available on the genomic features of E. meningoseptica. This study aims to characterize the geographical distribution, phylogenetic evolution, pathogenesis, and transmission of this bacterium. A systematic analysis of the E. meningoseptica genome revealed that a common ancestor of this bacterium existed 90 years ago. The evolutionary history showed no significant relationship with the sample source, origin, or region, despite the presence of genetic diversity. Whole genome sequencing data also demonstrated that E. meningoseptica bacteria possess inherent resistance and pathogenicity, enabling them to spread within the same hospital and even across borders. This study highlights the potential for E. meningoseptica to cause severe nosocomial outbreaks and horizontal transmission between countries worldwide. The available evidence is crucial for the development of evidence-based public health policies to prevent global outbreaks caused by emerging pathogens.

B6 from wastewater sludge and application in co-contaminated soil

Safener mefenpyr-diethyl (MFD) was applied to cereal crops along with herbicides to improve herbicide selectivity for crops and weeds. However, the degradation mechanism of MFD in the environment remains unclear. One MFD-degrading bacterium, Chryseobacterium sp. B6, was isolated from activated sludge. According to Box-Behnken's optimal design, the degradation efficiency of MFD can reach 92% under conditions of pH 7.5, 30 °C, and a MFD concentration of 184 mg L-1. The degradation half-life experiment showed that a high concentration of MFD (300 mg L-1) inhibited the degradation ability of strain B6. Additionally, strain B6 was resistant to Ba2+, Cr3+, Li+, Zn2+, and Cu2+. The MFD degradation products of strain B6 were detected by GC/MS and its degradation pathway was proposed. MFD was first hydrolyzed by a hydrolase to an intermediate (RS)-1-(2,4-dichlorophenyl)-5-methyl-2-pyrazoline-5-carboxylic acid ethyl ester-3-carboxylic acid, and then further degraded by a decarboxylase to form the intermediate (RS)-1-(2,4-dichlorophenyl)-5-methyl-2-pyrazoline-5-carboxylic acid ethyl ester, finally, it is completely degraded by strain B6. Furthermore, strain B6 could effectively remove MFD from MFD-contaminated soil, and the half-life of MFD was also significantly reduced in MFD and Cu2+ co-contaminated soil after inoculating strain B6. To our knowledge, strain B6 was the first strain reported to degrade safener MFD, and this study provides a valuable candidate to remediate the co-contaminated soil with MFD and Cu2+.

nov., isolated from the rhizosphere soil of Pyrola calliantha H

A novel Gram-stain-negative, aerobic, non-motile, rod-shaped bacterium, designated pc2-12T, was isolated from the rhizosphere soil of the herb Pyrola calliantha collected from arid areas of Tibet. The strain grew most vigorously with 1 % (w/v) NaCl, at pH 7.0 and at 25 °C. According to the results of 16S rRNA gene sequence analysis, pc2-12T was closely related to the members of the genus Chryseobacterium, with highest levels of sequence similarity to Chryseobacterium viscerum 687B-08T (98.42 %), Chryseobacterium oncorhynchi 701B-08T (98.11 %) and Chryseobacterium ureilyticum DSM 18017T (97.98 %). The average nucleotide identity values between pc2-12T and C. viscerum 687B-08T, C. oncorhynchi 701B-08T and C. ureilyticum DSM 18017T were 79.71, 79.49 and 79.26 %, respectively. The in silico DNA-DNA hybridisation values between pc2-12T and C. viscerum 687B-08T, C. oncorhynchi 701B-08T and C. ureilyticum DSM 18017T were 23.30, 23.00 and 22.90 %, respectively. The draft genome sequence of pc2-12T was 4.64 Mb long, with DNA G+C content of 37.0 mol%. The fatty acids contained in the cells of pc2-12T were mainly composed of iso-C15 : 0, iso-C17 : 0 3-OH and summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c). The main polar lipid was phosphatidylethanolamine. MK-6 was the sole respiratory quinone. On the basis of the results of analysis of all the data described, pc2-12T is considered to represent a novel species of the genus Chryseobacterium, for which the name Chryseobacterium pyrolae sp. nov., is proposed. The type strain is pc2-12T (=GDMCC 1.3256T= JCM 35712T).

nov., isolated from a stick insect rearing cage

Two strains of Chryseobacterium identified from different experiments are proposed to represent new species. Strain WLa1L2M3T was isolated from the digestive tract of an Oryctes rhinoceros beetle larva. Strain 09-1422T was isolated from a cage housing the stick insect Eurycantha calcarata. Sequence analysis of the 16S rRNA and rpoB genes found both strains to be similar but not identical to other Chryseobacterium species. Whole-genome sequencing suggested the isolates represent new species, with average nucleotide identity values ranging from 74.6 to 80.5 %. Genome-to-genome distance calculations produced values below 25.3 %, and digital DNA-DNA hybridization values were 13.7-29.9 %, all suggesting they are distinct species. The genomic DNA G+C content of WLa1L2M3T is approximately 32.53 %, and of 09-1422T is approximately 35.89 %. The predominant cellular fatty acids of strain WLa1L2M3T are C15 : 0 iso, summed feature 9 (C16 : 0 10OH or C17 : 1 iso ω6c), C17 : 0 iso 3OH, summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c), C15 : 0 iso 3OH, C15 : 0 anteiso and C13 : 0 iso, and those of strain 09-1422T are C15 : 0 iso, summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c), C17 : 0 iso 3OH, C15 : 0 anteiso, C15 : 0 iso 3OH, C16 : 1 ω7c, C17 : 0 2OH and C18 : 0. In addition, physiological and biochemical tests revealed phenotypic differences from related Chryseobacterium type strains. These cumulative data indicate that the two strains represent novel species of the genus Chryseobacterium for which the names Chryseobacterium oryctis sp. nov. and Chryseobacterium kimseyorum sp. nov. are proposed with WLa1L2M3T (=BCRC 81350T=JCM 35215T=CIP 112035T) and 09-1422T (=UCDFST 09-1422T=BCRC 81359T=CIP 112165T), as type strains, respectively.

Enhanced biodegradation of thiamethoxam with a novel polyvinyl alcohol (PVA)/sodium alginate (SA)/biochar immobilized Chryseobacterium sp H5

Long-term and extensive usage of thiamethoxam, the second-generation neonicotinoid insecticide, has caused a serious threat to non-target organisms and ecological security. Efficient immobilized microorganism techniques are a sustainable solution for bioremediation of thiamethoxam contamination. A Gram-negative aerobic bacterium Chryseobacterium sp H5 with high thiamethoxam-degrading efficiencies was isolated from activated sludge. Then we developed a novel polyvinyl alcohol (PVA)/sodium alginate (SA)/biochar bead with this functional microbe immobilization to enhance the biodegradation and removal of thiamethoxam. Results indicated that the total removal and biodegradation rate of thiamethoxam with PVA/SA/biochar (0.7 %) beads with Chryseobacterium sp H5 immobilization at 30 °C and pH of 7.0 within 7 d reached about 90.47 % and 68.03 %, respectively, much higher than that using PVA/SA immobilized microbes (75.06 %, 56.05 %) and free microbes (61.72 %). Moreover, the PVA/SA/biochar (0.7 %) immobilized microbes showed increased tolerance to extreme conditions. Biodegradation metabolites of thiamethoxam were identified and two intermediates were first reported. Based on the identified biodegradation intermediates, cleavage of C-N between the 2-chlorothiazole ring and oxadiazine, dichlorination, nitrate reduction and condensation reaction would be the major biodegradation routes of thiamethoxam. Results of this work suggested the novel PVA/SA/biochar beads with Chryseobacterium sp H5 immobilization would be helpful for the effective bioremediation of thiamethoxam contamination.

DEMBc1 strain: characteristics and potential to assist phytoremediation and promote plant growth

The effectiveness of phytoremediation is closely related to the various interactions between pollutants, soil particles, rhizosphere microorganisms, and plants. Therefore, the object of current study was a cadmium-tolerant bacterium isolated from the rye rhizosphere, with a high degree of genetic similarity to the genus Chryseobacterium. Chryseobacterium sp. DEMBc1 was able to grow with 36 different BiologGN2 carbon sources and show the adaptation to stress factors such as Cd (100 μg ml^-1), low temperature (8 °C), and salinity (2% NaCl). Furthermore, it was shown that DEMBc1 had the characteristics of plant growth-promoting microorganisms: it was able to produce ammonia, indole acetic acid, 1-aminocyclopropane-1-carboxylic acid deaminase, and siderophores, as well as solubilize Ca₃(PO₄)₃. After inoculation with DEMBc1, a significant decrease in the concentration of Cd was observed in the roots of Festuca ovina grown in Cd-polluted soil, compared to the non-inoculated Cd-polluted soil. It was also noticed that DEMBc1 produced a large amount of extracellular polymeric substances that were significantly higher than the cellular biomass. These polymers can form a barrier to reduce the translocation of Cd from the growth medium to the plant roots. According to the current study, DEMBc1 has a stabilizing potential and can decrease the mobility of Cd in the F. ovina rhizosphere, bioaccumulate metals in plant tissues, and effectively improve the bioavailability of nutrients, especially Fe, N, and P in a polluted environments.

Nutrient and organic pollutants removal in synthetic wastewater by Pseudomonas aeruginosa and Chryseobacterium sp./biofilter systems

Nutrient and organic pollution raise serious problems for aquatic ecosystems through the accumulation of organic carbon, the reduction of light penetration, and the loss of submerged aquatic vegetation. The over-enrichment of water with nitrogen and phosphorus leads to an imbalance in nutrient ratios, creating favorable conditions for toxic algal blooms, formation of oxygen-depleted water, etc. Thus, developing new technological solutions to reduce their amount is imperative. The present study investigates the capacity of Pseudomonas aeruginosa and Chryseobacterium sp. bacterial strains to form biofilm on solid support (biofilter), both individually and in tandem, using various analytical techniques. Also, the biofilm/biofilter systems' efficiency in removing nutrients such as nitrate, nitrite, ammonium, and phosphate ions from municipal wastewaters is assessed. The results showed a reduction of nutrient pollution of up to 91%, 98%, 55%, and 71% for nitrite, nitrate, ammonium, and phosphate ions. A reduction of about 78% of COD was also observed. The results were obtained in the absence of an additional aeration process, thus having a great potential for reducing total costs of wastewater treatment and developing ecological systems for wastewater management.

Chryseobacterium indologenes Bacteraemia: A Potential Cause of Early-onset Neonatal Sepsis in a Full-term Baby

Chryseobacterium indologenes is considered as an emerging pathogen known to cause pneumonia, bacteremia, and meningitis in children. It has been reported previously, mainly from the Indian subcontinent, as a rare cause of early-onset neonatal infection, mostly affecting preterm infants. We report the first case in the United Kingdom in which C. indologenes was isolated from the blood culture of a term infant who was clinically suspected of having early-onset neonatal sepsis. Our case had a good outcome, but mortality has been reported in published literature. A positive neonatal blood culture of C. indologenes should not automatically be considered as a contaminant; and a joint discussion between neonatologists and microbiologists should determine the appropriate management and antibiotic regimen. Key Words: Early-onset neonatal sepsis, Bacteremia, Chryseobacterium indologenes, Contaminant, Antibiotics.

Abcès mésentérique du au Chryseobacterium meningosepticum révélant la maladie de Castleman à localisation mésentérique chez un jeune adulte immunocompétent

Un abcès mésentérique causé par le Chryseobacterium meningosepticum est une entité clinique extrêmement rare, le plus souvent retrouvé sur un terrain d´immunodéficience et la maladie de Castleman peut être révélée par un abcès mésentérique. Nous présentons le cas d´un patient de 23 ans admis pour péritonite aiguë généralisée évoluant depuis 2 semaines. L´échographie abdominale montrait une masse hypoéchogène dans les anses grêles sans donner des plus amples détails. A la laparotomie, du pus avait été retrouvé dans la grande cavité et un abcès mésentérique présent dans le mésentère jéjunal à 35 cm de l´angle de Treitz sans aucune ouverture de l´anse en regard mais également une adénopathie mésentérique en regard de l´abcès. La pyoculture a isolé le Chryseobacterium meningosepticum et l´adénopathie mésentérique enlevée a montré à l´analyse histologique des anomalies structurales évoquant le type vascularisation hyalinisée de la maladie de Castleman. Le traitement a consisté en une incision et drainage de l´abcès avec résection de la coque et un nettoyage de la cavité abdominale au sérum physiologique. La Ciprofloxacine était le seul antibiotique sensible au Chryseobacterium meningosepticum. Les suites post-opératoires étaient simples avec sortie du patient au 10^e jour post-opératoire. Un suivi clinique et paraclinique du patient pendant 12 mois n´a objectivé aucune autre adénopathie ni aucune récidive. Le but de cette publication est de présenter un cas extrêmement rare associant un abcès mésentérique à Chryseobacterium meningosepticum et une maladie de Castleman unicentrique à localisation mésentérique chez un immunocompétent ainsi que les modalités de cette prise en charge.

Secondary metabolites released by the rhizosphere bacteria Arthrobacter oxydans and Kocuria rosea enhance plant availability and soil-plant transfer of germanium (Ge) and rare earth elements (REEs)

Here, we explore effects of metallophore-producing rhizobacteria on the plant availability of germanium (Ge) and rare earth elements (REEs). Five isolates of the four species Rhodococcus erythropolis, Arthrobacter oxydans, Kocuria rosea and Chryseobacterium koreense were characterized regarding their production of element-chelators using genome-mining, LC-MS/MS analysis and solid CAS-assay. Additionally, a soil elution experiment was conducted in order to identify isolates that increase solubility of Ge and REEs in soil solution. A. oxydans ATW2 and K. rosea ATW4 released desferrioxamine-, bacillibactin- and surfactin-like compounds that mobilized Ge and REEs as well as P, Fe, Si and Ca in soil. Subsequently, oat, rapeseed and reed canary grass were cultivated on soil and sand and treated with cells and iron depleted culture supernatants of A. oxydans ATW2 and K. rosea ATW4. Inoculation increased plant yield and shoot phosphorus (P), manganese (Mn), Ge and REE concentrations. However, effects of the inoculation varied substantially between the growth substrates and plant species. On sand, A. oxydans ATW2 increased accumulation of REEs in all plant species and root-shoot translocation in rapeseed, while K. rosea ATW4 enhanced REE accumulation in rapeseed only, without effects on other plant species. Sand-cultured oat plants showed increased Ge accumulation and root-shoot translocation in presence of A. oxydans ATW2 cells and K. rosea ATW4 supernatant; however, there was no effect on other plant species, irrespective the growth substrate used. In contrast, soil-cultured rapeseed showed enhanced REE accumulation in presence of cells of A. oxydans ATW2 while there were no effects on other plant species and Ge. The processes involved are not yet fully understood. Nevertheless, we demonstrated that chemical microbe-soil-plant relationships influence plant availability of nutrients together with Ge and REEs, which has major implications on our understanding of biogeochemical element cycling and development of sustainable bioremediation and biomining technologies.

H1

Sludge reduction is considered a main target for sludge treatment and an urgent issue for wastewater treatment. In this study, two dominant sludge-degrading strains, identified as Chryseobacterium sp. B4 and Serratia sp. H1, were used for inoculation in swine wastewater treatment to investigate the enhancement of sludge reduction. The results showed the volatile suspended solid (VSS) removal rate in experimental groups inoculated with Chryseobacterium sp. B4, Serratia sp. H1, and a combination of the two strains improved by 49.4%, 11.0%, and 30.5%, compared with the control with no inoculation. Furthermore, microbial community structure and functional prediction analyses indicated Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria could play an essential role in sludge reduction, and the dominant sludge-degrading strains B4 and H1 enhanced sludge reduction by strengthening carbohydrate, nucleotide, amino acid, and lipid metabolism and membrane transport functions. This study provides new insights into sludge reduction during wastewater treatment with dominant sludge-degrading strains.

Survivor microbial populations in post-chlorinated wastewater are strongly associated with untreated hospital sewage and include ceftazidime and meropenem resistant populations

Wastewater treatment plant (WWTP) effluent has been implicated in the spread of antibiotic resistant bacteria (ARB), including pathogens, as the WWTP environment contains multiple selective pressures that may increase mutation rates, pathogen survivability, and induce gene transfer between bacteria. In WWTPs receiving hospital sewage, this selective effect may be more pronounced due to increased concentrations of antibiotics, ARB, and clinical pathogens from hospital sewage. To determine the extent to which hospital sewage contributes to the microbial community of disinfected wastewater which is released into the environment, we used 16S rRNA sequencing of hospital sewage, WWTP influent, primary effluent, Post-Chlorinated Effluent, and receiving sediments in a combined sewage system to track changes in microbial community composition. We also sequenced the culturable survivor community resistant to β-lactam antibiotics within disinfected effluent. Using molecular source tracking, we found that the hospital sewage microbiome contributes an average of 11.49% of the microbial community in Post-Chlorinated Effluents, suggesting microorganisms identified within hospital sewage can survive or are enriched by the chlorination disinfection process. Additionally, we identified 28 potential pathogens to the species level, seven of which remained detectable in Post-Chlorinated Effluent and environmental sediments. When Post-Chlorinated Effluents were cultured on media containing β-lactam antibiotics ceftazidime and meropenem, a diverse antibiotic resistant survivor community was identified including potential human pathogens Bacillus cereus, Bacillus pumilus, and Chryseobacterium indologenes. Together, these results indicate that although wastewater treatment does significantly reduce pathogenic loads and ARBs, their continual presence in disinfected wastewater and receiving sediments suggests additional treatment and microbial tracking systems are needed to reduce human and animal health risks.

Chryseobacterium arthrosphaerae ventriculitis: A case report

INTRODUCTION

Chryseobacterium arthrosphaerae is a gram-negative bacteria, known for its intrinsic multidrug resistance, which can lead to treatment difficulties.

PATIENT CONCERNS

A 56-year-old male had an indwelling external ventricular drainage catheter for 6 months and had been frequently treated with antibiotics for nosocomial infections. He showed cerebrospinal fluid pleocytosis and an abrupt fever during hospitalization.

DIAGNOSIS

He was diagnosed as a ventriculitis caused by Chryseobacterium arthrosphaerae (C arthrosphaerae).

INTERVENTION

Initially, we used ciprofloxacin as the backbone in combination with minocycline (and rifampin). However, fever and pleocytosis persisted, and improvement was slow. We then switched the minocycline and rifampin regiment to trimethoprim/sulfamethoxazole. Following this switch of antibiotics, the patient's pleocytosis rapidly improved, allowing the replacement of his external ventricular drainage catheters. C arthrospharae was no longer growing in cerebrospinal fluid and he was recovered from ventriculitis.

OUTCOMES

The patient remains alive without any incidence of C arthrosphaerae recurrence.

CONCLUSION

We propose trimethoprim/sulfamethoxazole alone or in combination with ciprofloxacin to be good candidates for the treatment of ventriculitis by C arthrosphaerae.

isolated from clinically affected fish in California, USA

Chryseobacterium spp. (Family Flavobacteriaceae) are emergent fish pathogens in Europe, Asia and North America. In 2016-2017, 7 bacterial isolates were recovered from posterior kidney or spleen of cultured diseased rainbow trout Oncorhynchus mykiss (n = 1), green sturgeon Acipenser medirostris (n = 1), white sturgeon A. transmontanus (n = 2), blue ram cichlid Mikrogeophagus ramirezi (n = 1), and returning fall Chinook salmon O. tshawytscha (n = 2) from different freshwater systems. Bacterial colonies were visible after 24-48 h incubation at 20°C on agar media. Isolates were Gram-negative, rod-shaped, catalase and oxidase positive. Amplification and partial sequence analysis of the 16S rRNA and gyrB genes allocated the microorganisms to the genus Chryseobacterium sharing 97.2-99.6% similarity to 6 described Chryseobacterium spp. at the 16S rRNA locus, and 87.8-99.1% similarity at gyrB. Phylogenetic analyses in conjunction with percent sequence identity suggest some of the recovered isolates may represent novel Chryseobacterium subspecies or species. The pathogenicity of 5 isolates was evaluated experimentally in rainbow trout (n = 60), brown trout Salmo trutta (n = 60) and white sturgeon (n = 36) in flow-through freshwater at 18°C. Approximately 107 CFU fish-1 was injected in the epaxial musculature of anesthetized animals. Limited mortality was observed and no bacteria were recovered from dead or moribund fish post-challenge. Thirty days post-challenge, survivors were euthanized and multiple tissues were collected and fixed for histological analysis. No consistent histopathological changes were observed in challenged or control fish. While results suggest the recovered Chryseobacterium spp. may be opportunistic pathogens, further research is warranted to better understand the role of these bacteria in fish disease.

Successful Management of Elizabethkingia meningoseptica Meningitis with Intraventricular Vancomycin

Elizabethkingia meningoseptica, formerly Chryseobacterium meningosepticum usually causes neonatal meningitis and is a rare cause of nosocomial meningitis in adults. E. meningoseptica is resistant to most antibiotics, and the use of inactive drugs as empirical therapy may contribute to poor outcome in many patients. Vancomycin, alone or in combination with rifampicin, has been successful in the treatment of meningitis in infants1. We present a case of E. meningoseptica meningitis in an adult who was treated initially with intravenous vancomycin and oral rifampicin, but did not respond to the treatment. Thereafter, intraventricular vancomycin was added which resulted in good treatment response.

Elizabethkingia meningoseptica and Contact Lens Use

A 47-year-old man presented to our emergency department complaining of acute ocular pain and redness of his left eye. Ophthalmological antecedents included use of semi-rigid contact lens and primary open-angle glaucoma. Slit-lamp examination revealed a small central corneal ulcer associated with stromal inflammatory infiltrate. Scraping from the corneal ulcer was positive for Elizabethkingia meningoseptica. He was empirically treated with topical 0.5% levofloxacin and 0.3% gentamicin, and five weeks later the infection had resolved. In this case report we describe the uncommon association between contact lens and Elizabethkingia meningoseptica. Despite possible serious complications associated with this atypical agent, prompt diagnosis and adequate treatment lead to good visual prognosis.

Development of a single-replicon miniBYV vector for co-expression of heterologous proteins

In planta production of recombinant proteins, including vaccine antigens and monoclonal antibodies, continues gaining acceptance. With the broadening range of target proteins, the need for vectors with higher performance is increasing. Here, we have developed a single-replicon vector based on beet yellows virus (BYV) that enables co-delivery of two target genes into the same host cell, resulting in transient expression of each target. This BYV vector maintained genetic stability during systemic spread throughout the host plant, Nicotiana benthamiana. Furthermore, we have engineered a miniBYV vector carrying the sequences encoding heavy and light chains of a monoclonal antibody (mAb) against protective antigen (PA) of Bacillius anthracis, and achieved the expression of the full-length functional anti-PA mAb at ~300 mg/kg of fresh leaf tissue. To demonstrate co-expression and functionality of two independent proteins, we cloned the sequences of the Pfs48/45 protein of Plasmodium falciparum and endoglycosidase F (PNGase F) from Flavobacterium meningosepticum into the miniBYV vector under the control of two subgenomic RNA promoters. Agroinfiltration of N. benthamiana with this miniBYV vector resulted in accumulation of biologically active Pfs48/45 that was devoid of N-linked glycosylation and had correct conformation and epitope display. Overall, our findings demonstrate that the new BYV-based vector is capable of co-expressing two functionally active recombinant proteins within the same host cell.

Is Chryseobacterium indologenes a shunt-lover bacterium? A case report and review of the literature

Chryseobacterium indologenes is a non-fermentative Gram-negative bacillus formerly belonging to the Flavobacterium genus. It is widely found in water and soil, also on wet surfaces of the hospital environment. It rarely causes infections and is usually associated with altered immune status or indwelling devices. We present a case of ventriculoperitoneal shunt infection caused by C. indologenes in a premature pediatric patient. A six-month-old male infant with congenital hydrocephalus and ventriculoperitoneal shunt was admitted with complaints of irritability, high fever and projectile vomiting. He was diagnosed as suffering from meningitis based on the clinical symptoms and laboratory findings of cerebrospinal fluid. The ventriculoperitoneal shunt was externalized and cerebrospinal fluid samples were sent for bacterial cultures. The isolated bacterium was identified as C. indologenes by conventional methods and the BD Phoenix™ 100 (Becton Dickinson, MD, USA) fully automated microbiology system. Antimicrobial susceptibility testing was performed by the microdilution method and Kirby-Bauer's disk diffusion method according to the Clinical and Laboratory Standards Institute guidelines. The isolate was found susceptible to ciprofloxacin, levofloxacin, cefoperazone and trimethoprim-sulfamethoxazole, while it was resistant to amikacin, aztreonam, cefepime, ceftazidime, gentamicin, imipenem and ticarcillin-clavulanic acid. The treatment was started with trimethoprim-sulfamethoxazole and cefoperazone-sulbactam The ventriculoperitoneal shunt was then removed. The patient was fully healed after two weeks and discharged. Central nervous system infection is a rare form of C. indologenes infections. The case presented herein may make a useful contribution to the existing literature.

Chryseobacterium meningosepticum sepsis complicated with retroperitoneal hematoma and pleural effusion in a diabetic patient

Intra-abdominal infection due to Chryseobacterium meningosepticum is rare, and bacteremia complicated with pleural effusion and retroperitoneal hematoma caused by C. meningosepticum has not been reported previously. A 57-year-old diabetic man presented with bacteremia with retroperitoneal abscess and pleural effusion caused by C. meningosepticum on the 12th day of hospitalization. His clinical condition improved after antimicrobial therapy with levofloxacin and rifampin, debridement of the retroperitoneal hematoma and left-side chest tube insertion. Antibiotics were administered for 1 month, and he was later transferred to a local respiratory care ward under afebrile condition. C. meningosepticum should be included in the list of suspected nosocomial infections, especially in patients with immunocompromised status. Administration of appropriate antibiotics, such as quinolone, minocycline, trimethoprim-sulfamethoxazole or rifampin, and treatment of local infection improve the clinical outcome of patients with C. meningosepticum infection.

Chryseobacterium respiratory tract infections in patients with cystic fibrosis

OBJECTIVES

To investigate the prevalence of infections by Chryseobacterium in a cohort of cystic fibrosis (CF) patients, to assess the antimicrobial susceptibility of these strains, to examine their DNA fingerprinting and to evaluate some clinical outcomes of patients infected by these bacteria.

METHODS

Patients (300) attending a Regional Cystic Fibrosis Unit were enrolled in this study over 4 years. Natural or induced sputum samples were processed for microscopic and cultural tests. For phenotypic identification, automated and manual systems were used. For chemosusceptibility test, an automatic broth microdilution test and a disk-diffusion test were used and strains underwent DNA fingerprinting by pulsed-field gel electrophoresis (PFGE).

RESULTS

Thirty-five strains of Chryseobacterium were isolated from 22 patients. These strains showed a broad-spectrum antimicrobial resistance, with activity only for trimethoprim-sulfamethoxazole and quinolones. PFGE profiles of all isolates were generally heterogeneous, suggesting independent circulation.

CONCLUSIONS

This is the first report about clinical isolates of Chryseobacterium spp from CF patients in an Italian Centre. The infection by Chryseobacterium was not associated to a deterioration of pulmonary function and mortality: therefore, all patients infected by Chryseobacterium were co-infected by Pseudomonas aeruginosa and 3 of these were also co-infected by Burkholderia cepacia complex.

Lumboperitonial shunt infection due to Chryseobacterium indologenes

Chryseobacterium indologenes central nervous system infection has not been reported. We present a case of lumboperitoneal shunt infection caused by C. indologenes successfully treated with trimethoprim-sulfamethoxazole and rifampin in a pediatric patient. Forty-three additional cases of C. indologenes non-central nervous system infections reported in the English medical literature were reviewed. Risk factors for C. indologenes infections include underlying medical illnesses, underlying immunocompromising conditions and presence of indwelling intravascular devices.

[First documented case of Chryseobacterium meningosepticum meningitis in Central African Republic]

Chryseobacterium meningosepdcum is a rare but well-known causative agent of bacterial meningitis and can be the source of epidemic outbreak in neonatal facilities. It has rarely been documented in Africa. The purpose of this report is to describe the first case of C. meningosepticum meningitis in Central African Republic. The case that remained isolated occurred after dystocic delivery with resuscitation in a neonatal unit. Despite intensive care and appropriate antibiotic treatment, the newborn died on day 19. Identification of this rare cause of meningitis underlines the important role of the bacteriologic laboratory in managing bacterial meningitis in Africa. The strain of C. meningosepticum involved in this case was resistant to the main antibiotics used for first-intention treatment of neonatal bacterial meningitis, i.e., third-generation cefalosporins, chioramphenicol, and aminosides. This case also underlines the importance of familiarizing the medical staff with the dangers of nosocomial meningitis and reinforcing hospital hygiene measures.