Search

Simple Summary: Alcaligenes faecalis, a Gram-negative, aerobic bacterium commonly found in environmental settings and the human intestinal flora, can act as an opportunistic pathogen, particularly in immunocompromised individuals. This study presents a case involving a 3-month-old male German giant rabbit that succumbed to a severe, generalized infection caused by A. faecalis. The infection led to a severe infection and eventual death despite broad-spectrum antibiotic treatment. The isolated strain of A. faecalis demonstrated resistance to all tested antibiotics, complicating treatment efforts. This case underscores the significant challenges in managing A. faecalis infections due to their inherent antibiotic resistance and highlights the need for prompt identification and tailored therapeutic strategies. The findings emphasize the importance of continued surveillance and research into effective antimicrobial treatments for such multidrug-resistant pathogens. Alcaligenes faecalis is a Gram-negative, obligate aerobic bacillus commonly found in environmental settings, particularly in soil and water, as well as within the intestinal microbiota of humans and various animal species. This bacterium has the potential to act as an opportunistic pathogen, capable of causing severe infections in both humans and animals, which can sometimes result in fatal outcomes. Notably, A. faecalis is often characterized by a high degree of antibiotic resistance, complicating treatment efforts. In the current study, we present a case involving a 3-month-old male rabbit that developed a generalized infection, ultimately leading to the animal's death. Despite the administration of broad-spectrum systemic antibiotics, the treatment was ineffective in salvaging the animal's health. The isolated strain of A. faecalis demonstrated resistance to all tested antibiotics, underscoring the challenges associated with managing infections caused by this pathogen. This case highlights the significant impact of A. faecalis as an emerging threat in veterinary medicine, where its inherent antibiotic resistance further exacerbates the difficulty of effective treatment. [ABSTRACT FROM AUTHOR]

Keratinases are enzymes that catalyze the degradation of keratin, a resilient protein found in various biological materials such as: feathers, hair, and fish scales. Two isolates identified from previous work as Alcaligenes faecalis (SCA A1) and Pseudomonas aeruginosa (FSA A2) was used for keratinase production. The enzyme produced were purified using dialysis, ion exchange chromatography and gel filtration chromatography and the purified enzyme was characterized and used to check for keratin substrate specificity. Fermentation studies revealed that A. faecalis (SCA A1) displayed optimal growth at pH 9.5 and 10.5, particularly at higher temperatures (48°C, 58°C, and 68°C) when using Mackerel fish scales as the substrate. In contrast, P. aeruginosa (FSA A2) demonstrated better growth at pH 7.5 and 8.5, with the highest growth observed at 28°C and 38°C using both Mackerel and Elephant fish scales. Enzyme activity profiles showed that A. faecalis exhibited higher activity with Mackerel scales (65.7 U/ml), while P. aeruginosa showed greater activity using Elephant scales (68.1 U/ml). Purification of the keratinase enzymes from both isolates resulted in a 7-fold increase in specific activity, reaching 35.16 U/mg for A. faecalis and 37.80 U/mg for P. aeruginosa. Characterization of the purified enzymes revealed that both exhibited optimal activity at 70°C, with P. aeruginosa displaying slightly higher activity. The enzymes also shows good activity over a wide pH range, with optima at pH 7.3 and 6.3 for A. faecalis and P. aeruginosa, respectively. Substrate specificity analysis indicated that both enzymes had the highest activity towards Mackerel fish scales, followed by Casein, Human Hair, Chicken feathers, and Elephant fish scales. These findings highlight the potential of A. faecalis and P. aeruginosa for the biodegradation of fish scale waste, offering a sustainable solution for waste management and the production of valuable bioproducts. These results suggest that these keratinolytic bacteria could be utilized in the development of bioremediation strategies for fish processing waste. Additionally, the keratinase enzymes produced by these isolates could be utilized in various industrial applications, such as the production of animal feed supplements, leather processing, and the development of cosmetic and pharmaceutical products. [ABSTRACT FROM AUTHOR]

Wastewater treatment plants (WWTPs) at pig farms are significant environmental reservoirs of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs). In particular, contamination by multidrug-resistant Alcaligenes faecalis (MDR-AF) poses an increasingly severe threat to human health. However, no safe and effective method is currently available to hinder its dissemination in the environment. In this study, two hitherto unreported bacteriophages were screened. In addition, qPCR experiments demonstrated that applying these bacteriophage preparations to wastewater significantly eradicates MDR-AF and reduces ARGs by 0.7–2.5 orders of magnitude (P < 0.05), thereby substantially diminishing the risk of antibiotic resistance transmission. Furthermore, various characterizations, bacteriophage genomic analysis, and microbial community analysis indicated that these bacteriophage preparations possess safety, specificity, and high resilience, rendering them an efficient and eco-friendly biological control measure. [Display omitted] • Bacteriophages CASP1 & CASP2 isolated to target multidrug-resistant (MDR) bacteria. • CASP1 & CASP2 reduce MRD Alcaligenes faecalis & antibiotic resistance genes (ARGs). • Monotypes cause more inactivation than mixed phages owing to competitive inhibition. • Mixed phages decrease ARGs more effectively than monotypic phages. • Both bacteriophages are confirmed as environmentally friendly, safe, and efficient. [ABSTRACT FROM AUTHOR]

For successful management of pollution problems, the use of bacteria is now a popular and widespread technique. Alcaligenes faecalis, an inhabitant of the natural environment, is equipped with machinery for cleaning up different types of contaminants, including heavy metals and xenobiotics. A. faecalis, a gram‐negative, flagellated, nonfermentive, aerobic member of the subgroup proteobacteria, often shows anaerobic respiration using nitrate or nitrite as terminal electron acceptors. It is also gifted with the power of nitrogen fixation and thereby could be used as a biofertilizer. The bacterium also has the unique ability to act as a probiotic and can often be used as a biocontrol agent due to its antimicrobial properties. Hence, for sustainable management of the environment, various strains of this bacterium as active bio‐remediators, bio‐pesticides, biofertilizers, and probiotics are being increasingly applied. [ABSTRACT FROM AUTHOR]

Heterotrophic nitrification-aerobic denitrification (HN-AD) bacteria are the key functional microorganisms needed to achieve simultaneous nitrification and denitrification (SND). In this study, 25 strains of HN-AD bacteria were successfully isolated from a stable landfill leachate biochemical treatment system, of which 10 strains belonged to Firmicutes and 15 strains belonged to Proteobacteria. Bacillus subtilis F4 and Alcaligenes faecalis P4 displayed good tolerance at a wide range of ammonia nitrogen (NH4+-N) concentrations. When the C/N ratio was 20, the removal rates of ammonia nitrogen were 90.1% and 89.5%, and the chemical oxygen demand (COD) removal rates were 92.4% and 93.9%, respectively. The napA gene encoding periplasmic nitrate reductase (Nap) and the nirS gene encoding nitrite reductase (Nir) were detected, and nitrogen balance showed assimilation and HN-AD was the main nitrogen metabolism mode in both strains. The use of immobilization materials could increase removal rate of ammonia nitrogen by 21.1% and 29.6%, respectively. The research results of this work can provide theoretical basis and technical support for the practical application of HN-AD bacteria to enhance the treatment of high ammonia nitrogen wastewater with high efficiency and low consumption. [ABSTRACT FROM AUTHOR]

Alcaligenes faecalis is a Gram-negative, rod-shaped bacterium that is common in the environment and has been reported to have various bioactive metabolites of industrial potential applications, including antifungal, antibacterial, antimycobacterial, antiparasitic, anticancer, antioxidant activities. In this review, we highlighted and discussed the respective metabolites, pointing out their chemical diversities, purification, current challenges, and future directions. A. faecalis has an industrial role in biodegradation, biosurfactants, and different enzyme production. In this review, the up-to-date various Response Surface Methodology methods (RSM) that can be employed for statistical optimization of the bioactive secondary metabolites have been discussed and highlighted, pointing out the optimal use of each method, current challenges, and future directions.

Alcaligenes faecalis is a Gram-negative, obligate aerobic bacillus commonly found in environmental settings, particularly in soil and water, as well as within the intestinal microbiota of humans and various animal species. This bacterium has the potential to act as an opportunistic pathogen, capable of causing severe infections in both humans and animals, which can sometimes result in fatal outcomes. Notably, A. faecalis is often characterized by a high degree of antibiotic resistance, complicating treatment efforts. In the current study, we present a case involving a 3-month-old male rabbit that developed a generalized infection, ultimately leading to the animal’s death. Despite the administration of broad-spectrum systemic antibiotics, the treatment was ineffective in salvaging the animal’s health. The isolated strain of A. faecalis demonstrated resistance to all tested antibiotics, underscoring the challenges associated with managing infections caused by this pathogen. This case highlights the significant impact of A. faecalis as an emerging threat in veterinary medicine, where its inherent antibiotic resistance further exacerbates the difficulty of effective treatment.

Foot ulcers are common among diabetic patients and can lead to severe bacterial infection. The aim of the study was to determine the antibacterial activity of Andrographis paniculata root extracts on clinical pathogens isolated from foot ulcers of diabetic patients. A total of 5 typed strains comprising of Acinetobacter johnsonii strain JUQ303 Pseudomonas rhodesiae strain YHBT5, Alcaligenes faecalis strain 2, Alcaligenes faecalis strain N148 and Alcaligenes faecalis strain 3 were isolated from patients attending clinics at the National Orthopedic Hospital, Enugu. Roots of Andrographis paniculata were obtained from a local garden in Anaocha local government area of Anambra State. They were pulverized and extracted using ethanol, acetone and water solvents. These crude extracts were reconstituted using 5ml of Dimethyl sulfoxide (DMSO) to obtain concentrations of 200, 100, 50, 25, 12.5, 6.25, 3.125 and1.56mg/ml. The isolates were screened for sensitivity to the plant extracts using agar well diffusion method. Antibiotic susceptibility pattern of these isolates was analyzed using Kirby-Bauer disc diffusion method. The aqueous extract showed highest zone of inhibition of 12mm on Acinetobacter johnsonii, 11mm on Psedomonasrhodesiae, 10mm on Alcaigenes faecalis strain 2, 9mm on Alcaligenes faecalis strain N148 and 7mm on Alcaligenes faecalis strain 3, respectively at the concentration of 200mg/ml. At lower concentrations of 12.5mg/ml, 6.25mg/ml, 3.125mg/ml and 1.56mg/ml, the aqueous extracts showed no inhibition on tested isolates. The MIC of the ethanol root extract of Andrographis paniculata were recorded at 12.5mg/ml,25mg/ml, 50mg/ml, 50mg/ml and 12.5mg/ml on Acinetobacter johnsonii strain JUQ303, Pseudomonas rhodesiae strain YHBT5, Alcaligenes faecalis strain 2, Alcaligenes faecalis strain N148 and Alcaligenes faecalis strain 3, respectively. The MIC of the acetone root extract were recorded at 25mg/ml, 100mg/ml, 50mg/ml, 25mg/ml and 100mg/ml on Acinetobacter johnsonii, Psedomonasrhodesiae, Alcaligenes faecalis strain 2,Alcaligenesfaecalis strain, Alcaligenes faecalis strain 3 respectively while the MIC of the aqueous root extract were recorded at100mg/ml, 200mg/ml, 200mg/ml, 100mg/ml and 200mg/ml Acinetobacter johnsonii, Psedomonasrhodesiae, Alcaligenes faecalis strain 2, Alcaligenes faecalis strain, Alcaligenes faecalis strain 3 respectively. The aqueous extract showed no bactericidal effect on tested isolates. From the study, ethanol extract of A. paniculataroots showed the highest antibacterial potency on clinical pathogens isolated from diabetic foot ulcers than the acetone and aqueous extracts. Andrographis paniculata plant is easily accessible, potent, economical and safe to man, therefore, this study encourages the use of plant extracts in the treatment of human diseases caused by these pathogens. [ABSTRACT FROM AUTHOR]

In recent years, bio-reinforced composite materials have occupied an important class among the materials of mass use in our daily lives thanks to their potential advantages such as lightness, low cost, ease of implementation, and in particular biodegradation. The latter has been the objective of several studies focusing particularly on poorly biodegradable polymers, among these polymers we find polyamide 6 (PA6). It is a semi-crystalline polymer, distinguished by its good mechanical properties, excellent chemical and thermal stability, and low price compared to other polyamides. In this research, we investigated the impact of reinforcing PA6 with peanut shell powder (PSP), olive pomace powder (OPP), and plaster (PL) on its biodegradation process. Our objective was to determine whether the incorporation of these reinforcements accelerates, delays, or has no effect on PA6 biodegradation. To achieve this, we conducted degradation experiments using the bacterium Alcaligenes faecalis (AF), isolated from the public landfill of Meknes, Morocco. Our findings revealed intriguing insights into the biodegradation behavior of the PA6 composites. Specifically, the incorporation of PSP significantly enhanced PA6 biodegradation, resulting in a notable 38 % weight loss. Conversely, the inclusion of OPP led to a delay in biodegradation, with only a 19 % weight loss observed. Interestingly, the addition of plaster exhibited a biodegradation pattern similar to that of raw PA6. Furthermore, we utilized FTIR and SEM coupled with EDS elemental analysis to confirm the biodegradation of the composites. These techniques provided valuable insights into the structural, morphological, and elemental changes undergone by the composites during the biodegradation process. Overall, our study contributes novel insights into the biodegradation dynamics of PA6 composites reinforced with natural materials. By elucidating the effects of reinforcement on biodegradation, our research paves the way for the development of sustainable and eco-friendly composite materials.

Octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propanoate (ODHP) was extracted in a previous study from the culture broth of soil isolate Alcaligenes faecalis MT332429 and showed a promising antimycotic activity. This study was aimed to formulate ODHP loaded β-cyclodextrins (CD) nanosponge (NS) hydrogel (HG) to control skin fungal ailments since nanosponges augment the retention of tested agents in the skin. Box-Behnken design was used to produce the optimized NS formulation, where entrapment efficiency percent (EE%), polydispersity index (PDI), and particle size (PS) were assigned as dependent parameters, while the independent process parameters were polyvinyl alcohol % (w/v %), polymer-linker ratio, homogenization time, and speed. The carbopol 940 hydrogel was then created by incorporating the nanosponges. The hydrogel fit Higuchi's kinetic release model the best, according to in vitro drug release. Stability and photodegradation studies revealed that the NS-HG remained stable under tested conditions. The formulation also showed higher in vitro antifungal activity against Candida albicans compared to the control fluconazole. In vivo study showed that ODHP-NS-HG increased survival rates, wound contraction, and healing of wound gap and inhibited the inflammation process compared to the other control groups. The histopathological examinations and Masson's trichrome staining showed improved healing and higher records of collagen deposition. Moreover, the permeability of ODHP-NS-HG was higher through rats' skin by 1.5-folds compared to the control isoconazole 1%. Therefore, based on these results, NS-HG formulation is a potential carrier for enhanced and improved topical delivery of ODHP. Our study is a pioneering research on the development of a formulation for ODHP produced naturally from soil bacteria. Key points: • Octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propanoate was successfully formulated as a nanosponge hydrogel and statistically optimized. • The new formula exhibited in vitro good stability, drug release, and higher antifungal activity against C. albicans as compared to the fluconazole. • Ex vivo showed enhanced skin permeability, and in vivo analysis showed high antifungal activity as evidenced by measurement of various biochemical parameters and histopathological examination. [ABSTRACT FROM AUTHOR]

The removals of emerging contaminants (EC) through adsorption and biodegradation by Alcaligenes faecalis no.4 (A. faecalis no.4) and its combination with heterotrophic microorganisms presented in acclimated activated sludge were evaluated. The studied EC included bisphenols (BPA), di-n-butyl phthalate (DBP), and bis-2-ethyl hexyl phthalate (DEHP). Improved removals of those compounds under the presence of A. faecalis no.4 were observed. Batch experiments carried out in the absence of autotrophic nitrifying activities revealed that heterotrophic nitrification significantly contributed to the compound degradation process. Integration of mixed sludge was found effectively applied to leachate in which A. faecalis no.4 posed a higher growth rate than other acclimated heterotrophic bacteria.

The disposal of human faecal sludge (FS) is one of the biggest environmental problems. It can be solved by using FS as an agricultural fertilizer. However, this is hampered by the presence of pathogenic microflora and high organic matter content in FS. This paper proposes a novel treatment approach for FS to address these issues. It consists of the preliminary aerobic incubation of FS with the bioaugmentation of bacterial culture Alcaligenes faecalis DOS7. A. faecalis has been shown to inhibit the growth of various microorganisms, including coliforms (Escherichia coli). For the treatment of FS, three tanks with a volume of 1 m3 each, equipped with a mixing and aeration system, were used. A. faecalis culture was introduced into two experimental tanks at a concentration of 106 and 6.5 × 106 cells/mL. The 11-day incubation in the experimental tanks resulted in the decomposition of organic matter in the FS that was several times faster than in the control (p < 0.05). Total suspended solids decreased 2.5–5-fold, chemical oxygen demand decreased 1.8-fold, 5-day biochemical oxygen demand decreased 1.5–2-fold. At the same time, after 4 days of incubation, no coliforms were detected in the experimental tanks, and in the control, coliforms accounted for 13.9% of the total number of cells after 11 days of incubation. The proposed method of FS pretreatment is a real alternative to the existing ones and can be used both individually and in combination with other methods, for example, composting. [ABSTRACT FROM AUTHOR]

The conduct of a field trial in the 2021-2022 cropping season assessed the economic feasibility and effect of using locally produced microbial biofertilizers on the growth and yield traits of wheat (Triticum aestivum L.). The manures of Providencia vermicola, Alcaligenes faecalis, and Raoultella planticola served as sample treatments in the study. The research was in a randomized complete block design at the Agricultural Experiment and Research Station (31°20'19"N 45°17'20"E), College of Agriculture, Al-Muthanna University, Iraq. Microbial fertilizers were the first factor, with the second factor comprising two levels of mineral fertilizers, i.e., a) no chemical fertilizer and b) using half of the recommended chemical fertilizer, addressing the interactions between biofertilizers and chemical fertilizers, having a two-factor experiment. Field results showed that triple biofertilization consisting of A. faecalis, R. planticola, and P. vermicola proved superior based on grain yield and biomass using half of the recommended fertilizer (P7) (8.038 t ha-1 and 24.938 t ha-1). In turn, the economic analysis results were consistent with the technical outcomes, as treatment P7 recorded the highest profit amounting to USD 483.625 ha-1. In addition to recording the highest revenue per ha at the rate of 6.2477, treatment P7 for the level of fertilization F1 recorded the maximum level, amounting to about USD 144.284, 165,298.65, and 48,362.5 ha-1 for the criteria of the invested USD return, productive profitability, and added value, respectively. [ABSTRACT FROM AUTHOR]

Indole is a nitrogenous heterocyclic aromatic pollutant often detected in various environments. An efficient indole degrading bacterium strain IITR89 was isolated from River Cauvery, India, and identified as Alcaligenes faecalis subsp. phenolicus. The bacterium was found to degrade ~ 95% of 2.5 mM (293.75 mg/L) of indole within 18 h utilizing it as a sole carbon and energy source. Based on metabolite identification, the metabolic route of indole degradation is indole → (indoxyl) → isatin → (anthranilate) → salicylic acid → (catechol) → (Acetyl-CoA) → and further entering into TCA cycle. Genome sequencing of IITR89 revealed the presence of gene cluster dmpKLMNOP, encoding multicomponent phenol hydroxylase; andAbcd gene cluster, encoding anthranilate 1,2-dioxygenase ferredoxin subunit (andAb), anthranilate 1,2-dioxygenase large subunit (andAc), and anthranilate 1,2-dioxygenase small subunit (andAd); nahG, salicylate hydroxylase; catA, catechol 1,2-dioxygenase; catB, cis, cis-muconate cycloisomerase; and catC, muconolactone D-isomerase which play an active role in indole degradation. The findings strongly support the degradation potential of strain IITR89 and its possible application for indole biodegradation. [ABSTRACT FROM AUTHOR]

Background and Objectives: Sustainability in agricultural systems without compromising the environmental quality and conservation is one of the major concerns of today's world. The excessive use of agrochemicals is posing serious threats to the environment. Therefore identification of efficient plant growth promoting (PGP) bacteria as an alternative to chemically synthesized fertilizers is of great interest. Materials and Methods: In the present investigation, forest soil samples collected were used for isolation of efficient plant growth promoting bacteria. Results: Total of 14 bacteria were isolated, and tested for various PGP properties. Out of the 14 isolates, four isolates labelled as BKOU-1, BKOU-8, BKOU-13 and BKOU-14 showed significant plant growth promoting traits, hydrolytic enzyme production and effectively restricted the mycelial development of phyto-pathogenic fungi (Fusarium oxysporum and Macrophomina phaseolina). 16 S rRNA gene sequences of the bacterial isolates BKOU-1, BKOU-8, BKOU-13 and BKOU-14 were found to have maximum identity with Bacillus aerius, Bacillus infantis, Alcaligenes faecalis and Klebsiella Oxytoca respectively. All four bacterial isolates nucleotide sequences were submitted to GenBank and NCBI accession numbers were generated as follows: OL721916, OL721918, OL721919 and OL721926. Conclusion: According to the findings of the study, these PGPR could be employed as biofertilizers/ biopesticides to boost crop yield of different crops in sustainable manner. [ABSTRACT FROM AUTHOR]

Introduction: Diabetes is a non-contagious disease, but it can cause various complications. One of the most common complications of diabetes is diabetic ulcers. Diabetic ulcers are infections that occur in the legs of diabetics due to the destruction of the deepest skin tissue. Recent studies have reported the presence of Alcaligenes faecalis with extensive drug resistance (XDR) properties as a cause of diabetic ulcers. Bacteriophages are known to have the ability to infect bacteria specifically so that they can be used as an alternative solution for treating diabetic ulcers. The purpose of this study was to determine the characteristics of bacteriophages capable of infecting Alcaligenes faecalis bacteria. Material and methods: The method used is the spot test method, host range, and identification of nucleic acid types. Results: The results showed that the 6 bacteriophages isolated, namely AFaV1, AFaV2, AFaV3, AFaV4, AFaV5, and AFaV6, had cloudy plaques with a diameter of ±3 mm. AFaV1, AFaV2, and AFaV4 isolates could infect all bacteria used; they were Klebsiella pneumoniae, Escherichia coli, and Staphylococcus aureus. Meanwhile, bacteriophage isolates AFaV3, AFaV5, and AFaV6 could infect Klebsiella pneumoniae and Staphylococcus aureus bacteria only. The nucleic acid types of the 6 bacteriophage samples were dsDNA with band length > 1 Kb. Conclusions: The 6 isolates that were isolated had the ability to infect by forming a prophage that could inhibit the growth of Alcaligenes faecalis and other pathogenic bacteria in diabetic ulcers. [ABSTRACT FROM AUTHOR]

Abstract Background Drug-resistant bacteria are important carriers of antibiotic-resistant genes (ARGs). This fact is crucial for the development of precise clinical drug treatment strategies. Long-read sequencing platforms such as the Oxford Nanopore sequencer can improve genome assembly efficiency particularly when they are combined with short-read sequencing data. Results Alcaligenes faecalis PGB1 was isolated and identified with resistance to penicillin and three other antibiotics. After being sequenced by Nanopore MinION and Illumina sequencer, its entire genome was hybrid-assembled. One chromosome and one plasmid was assembled and annotated with 4,433 genes (including 91 RNA genes). Function annotation and comparison between strains were performed. A phylogenetic analysis revealed that it was closest to A. faecalis ZD02. Resistome related sequences was explored, including ARGs, Insert sequence, phage. Two plasmid aminoglycoside genes were determined to be acquired ARGs. The main ARG category was antibiotic efflux resistance and β-lactamase (EC 3.5.2.6) of PGB1 was assigned to Class A, Subclass A1b, and Cluster LSBL3. Conclusions The present study identified the newly isolated bacterium A. faecalis PGB1 and systematically annotated its genome sequence and ARGs.

Background and Objectives: Sustainability in agricultural systems without compromising the environmental quality and conservation is one of the major concerns of today’s world. The excessive use of agrochemicals is posing serious threats to the environment. Therefore identification of efficient plant growth promoting (PGP) bacteria as an alternative to chemically synthesized fertilizers is of great interest. Materials and Methods: In the present investigation, forest soil samples collected were used for isolation of efficient plant growth promoting bacteria. Results: Total of 14 bacteria were isolated, and tested for various PGP properties. Out of the 14 isolates, four isolates labelled as BKOU-1, BKOU-8, BKOU-13 and BKOU-14 showed significant plant growth promoting traits, hydrolytic enzyme production and effectively restricted the mycelial development of phyto-pathogenic fungi (Fusarium oxysporum and Macrophomina phaseolina). 16 S rRNA gene sequences of the bacterial isolates BKOU-1, BKOU-8, BKOU-13 and BKOU-14 were found to have maximum identity with Bacillus aerius, Bacillus infantis, Alcaligenes faecalis and Klebsiella Oxytoca respectively. All four bacterial isolates nucleotide sequences were submitted to GenBank and NCBI accession numbers were generated as follows: OL721916, OL721918, OL721919 and OL721926. Conclusion: According to the findings of the study, these PGPR could be employed as biofertilizers/ biopesticides to boost crop yield of different crops in sustainable manner.

We conducted a series of column experiments on tailing heap samples from the Picacho mine in California to determine the ability of the native Gram-negative bacteria, Alcaligenes faecalis, to leach gold. To mimic heap leaching using our technique, unprocessed and unsorted tailings of mixed grain sizes were placed into columns and leached for three weeks with four treatments: (1) deionized water, (2) bacteria, (3) NaCN by bacteria and (4) NaCN. In all of the experimental runs, the total Au (mg) recovered from the columns treated with A. faecalis and NaCN followed by A. faecalis yielded gold amounts that were higher than those from the deionized water control, and lower than the columns treated with cyanide. However, the total yields were variable across runs, which we attribute to the inherent heterogeneity of gold distribution in the samples. Statistical tests show that the yields from the treatments employing bacteria and/or cyanide were different from those that employed deionized water alone. Our results support previous studies that showed that exudates of A faecalis promoted reduction of Au3+, catalyzing extracellular Au0 particles under alkaline conditions. We propose that A. faecalis is a possible novel alternative to cyanide treatment for recovering Au from mine tailings, and recommend optimization of the method. [ABSTRACT FROM AUTHOR]

Nitrification by heterotrophic microorganisms is an important part of the nitrogen cycle in the environment. The enzyme responsible for the core function of heterotrophic nitrification is pyruvic oxime dioxygenase (POD). POD is a non-heme, Fe(II)-dependent enzyme that catalyzes the dioxygenation of pyruvic oxime to produce pyruvate and nitrite. To analyze the catalytic mechanism of POD, the crystal structure of POD from Alcaligenes faecalis (AfPOD) was determined at 1.76 Å resolution. The enzyme is a homotetramer, and the subunit structure is homologous to those of class II aldolases, in particular, a zinc-dependent L-fuculose-1-phosphate aldolase. The active site of the subunit is located at the bottom of a cleft formed with an adjacent subunit. The iron ion at the active site is coordinated by three histidines and three water molecules in an octahedral geometry. The putative oxygen tunnel was connected between the active site and the central cavity of the tetramer. The N-terminal region of AfPOD, which is essential for catalytic activity, is disordered in the crystal. Structure prediction with AlphaFold2 combined with mutational experiments suggested that the disordered N-terminal region adopts an α-helix conformation and participates in the formation of the active site. The catalytic mechanism of the dioxygenase reaction by POD is discussed on the basis of the molecular docking model.IMPORTANCEOur knowledge of nitrification has increased considerably in recent decades with the discovery of new nitrifying microorganisms and the characterization of their biochemical processes. Some heterotrophic bacteria and fungi are known to show nitrification activities, but the molecular mechanisms have been poorly understood. Here, we performed a structural characterization of pyruvic oxime dioxygenase (POD), a key enzyme in heterotrophic nitrification that produces nitrite from ammonia using pyruvic oxime as an intermediate. Structural and enzymatic analyses revealed that POD is a unique dioxygenase with features such as an aldolase backbone, an N-terminal α-helix, and an oxygen tunnel. Our results provide insights not only into the molecular mechanisms but also into the design of specific inhibitors of heterotrophic nitrification., Competing Interests: The authors declare no conflict of interest.

L-arginase is one of the enzymes that have been used as therapy for cancer treatment. L-arginase catabolise L-arginine and reduce tumour growth by making them susceptible to other anti-cancer drugs. Previous works have focused on the use of radiotherapy and chemotherapy for the treatment of metastatic cells. However, both radiotherapy and chemotherapy have been reported to have severe side effects. This necessitates the development of other agents such as enzymes with minimal side effects. This study therefore examined the production of L-arginase and determination of the optimum fermentation conditions. Isolated bacteria were screened using rapid plate assay in order to determine their ability to produce L-arginase. Medium component includes L-arginine and relevant salts. Enzyme activity was determined using calorimetric assay. The promising isolate was selected and primed for identification using molecular technique. The highest zone of colour change was produced by Alcaligenes faecalis. The optimum incubation period was 60 hours. Optimum agitation rate was 150 revolution per minute. Enzyme yield was 163±0.78 U/mL when optimum fermentation conditions were used for enzyme production. The molecular weight of L-arginase determined was 120 kilodalton. Alcaligenes faecalis isolated during this work can be taken as a promising isolate for the large-scale production of L-arginase. There should be further search for other microorganisms with the potential to produce other industrially important enzymes. [ABSTRACT FROM AUTHOR]

Using chemical fertilizers in agriculture increases production and improves the quality of the product; however, their higher usage globally has brought forth damage to ecosystems. Using biofertilizers is a better strategy to reduce the use of chemical fertilizers and ultimately increase soil fertility. This study aimed to isolate, identify, and characterize bacteria from the soil rhizosphere of medicinal plants (Rumex tuberosus L. and Verbascum sp.) for in vivo screening. Nitrogen fixation, phosphate solubilization, HCN, ammonia levels, Lipase, protease, catalase and siderophore production biochemical tests were also conducted. The two isolates that gave positive results from the biochemical tests were chosen out of 25 for further experiments. Based on 16S rRNA sequencing analysis the isolated organisms were identified as Alcaligenes faecalis Go1 (Accession No. OP001725) and Bacillus subtilis T11 (Accession No. OP218376). The compound fertilizer NPK was used as the positive control for field experiments, while selected stains were individually and in-combination were tested on potato crops as inoculum, over two successive cropping seasons. Plant height, number of tubers per plant, chlorophyll content, and tuber weight all increased for both isolated bacterial strains. The quality of the potato tubers was checked through visual observation for the presence or absence of disease symptoms. The treated tubers exhibited excellent quality, remaining free from any signs of disease, however, the control tubers showed infections with (Streptomyces scabiei, Fusarium sp., F. solani and Erwinia amylovora). The soil analyzed after harvesting both bacteria increased percentages of P, Ca2+, Mg2+, Na+, K+, SO4, total nitrogen content and total organic matter. The findings showed that the tested bacterial isolates could replace the use of chemical fertilizers in the production of potatoes. • Alcaligenes faecalis and Bacillus subtilis boosted plant growth significantly. • Treated potatoes showed higher quality and remained disease-free. • Application of these bacteria improved soil fertility by increasing essential nutrient levels. [ABSTRACT FROM AUTHOR]

Simple Summary: Every year, more than a million tons of fecal sludge (FS) containing biocides based on quaternary ammonium compounds and guanidine derivatives, which are widely used for FS deodorization and control of microbial activity, are generated in the environmentally safe toilet complexes of Russian Railways trains. Higher disposal costs for such biocide-contaminated FS due to activated sludge toxicity increases pressure on sanitary equipment servicing companies («Ecotol Service» LLC) to more efficiently discharge FS to wastewater treatment plants. In this work, we have developed a new environmentally friendly approach to reducing the toxicity of FS, based on the use of biological products from biocide-resistant bacterial strains isolated from FS. Our approach has proven to be effective in a series of FS biodegradation experiments, biological oxygen demand tests, and a newly developed disk-diffusion bioassay. Toxic shock caused by the discharge of biocide-contaminated fecal sludge (FS) from chemical toilets to conventional wastewater treatment plants (WWTP) can be a major problem in activated sludge operation. It is necessary to develop new environmental approaches to mitigate the toxicity of biocides in order to avoid degrading the performance of WWTP. "Latrina", a chemical toilet additive containing didecyldimethylammonium chloride and polyhexamethylene guanidine, is widely used in environmentally safe toilet complexes (ESTC) on Russian railway trains to deodorize FS and control microbial activity. In this work, seven biocide-resistant bacterial strains were isolated and identified from the FS of ESTC. The values of the minimum inhibitory and bactericidal concentrations of biocides for the isolated strains were 4.5–10 times higher than for the collection microorganisms. The bacterium Alcaligenes faecalis DOS7 was found to be particularly resistant to "Latrina", the minimum inhibitory concentration of which was almost 30 times higher than recommended for ESTC. Biological products based on isolated bacterial strains proved to be effective for FS biodegradation under both aerobic and anaerobic conditions. The results of the biochemical oxygen demand test and the newly developed disk-diffusion bioassay confirmed that isolated strains contribute to reducing toxicity of biocidal agents in FS. Hyper-resistance, non-pathogenicity, and potential plant growth-promoting ability make A. faecalis DOS7 promising for use in various biological products for wastewater treatment and bioremediation of soils contaminated with biocides, as well as in agriculture to increase plant productivity. [ABSTRACT FROM AUTHOR]

Simple Summary: The body of an average person weighing 70 kg contains approximately 39 trillion bacterial cells, which densely inhabit the gastrointestinal tract, skin, mucous membranes, etc. Bacteria respond to the signaling molecules in the human body, regulate the expression of the necessary genes, and thus adapt to the physiology of the host. Signaling molecules include hormones, neurotransmitters, immune system molecules, as well as natriuretic peptides, which are involved in the regulation of the circulatory system, water and electrolyte metabolism, and adipose tissue metabolism. Brain natriuretic peptide (BNP) is secreted by the ventricles during congestion and signals heart failure. This study showed that the presence of BNP in the growth medium of human symbiont bacteria affects their growth characteristics, survival, and stress resistance, including antibiotic resistance. It was concluded that bacterial populations that develop in a healthy person at a BNP level of up to 250 pg/mL will be more stress resistant than in a person suffering from heart failure. Our findings are promising to be used both in clinical medical practice and in the production of bacterial preparations for cosmetology, agriculture, and waste management. Brain natriuretic peptide (BNP) is secreted by the ventricles of the heart during overload to signal heart failure. Slight bilateral skin itching induced by BNP has been associated with response activity of the skin microbiota. In this work, we studied the effect of 25–250,000 pg BNP/mL on the growth, long-term survival, and stress (H2O2, antibiotics, salinity, heat and pH shock) resistance of human symbiont bacteria: Gram-positive Micrococcus luteus C01 and Gram-negative Alcaligenes faecalis DOS7. The effect of BNP turned out to be dose-dependent. Up to 250 pg BNP/mL made bacteria more stress resistant. At 2500 pg BNP/mL (heart failure) the thermosensitivity of the bacteria increased. Almost all considered BNP concentrations increased the resistance of bacteria to the action of tetracycline and ciprofloxacin. Both bacteria survived 1.3–1.7 times better during long-term (up to 4 months) storage. Our findings are important both for clinical medical practice and for practical application in other areas. For example, BNP can be used to obtain stress-resistant bacteria, which is important in the collection of microorganisms, as well as for the production of bacterial preparations and probiotics for cosmetology, agriculture, and waste management. [ABSTRACT FROM AUTHOR]

Acrylates/acrylic-containing chemicals are components of paints. During industrial production and applications, the acrylates and acrylic-containing compounds could contaminate/accumulate in water bodies and soil systems, hence the need for bioremediation. This study aimed to investigate the in vitro biodegradation of acrylic based paint; using an indigenous bacterial isolate namely; Alcaligenes faecalis and optimization of its activity in shake cultures. The bacterial isolate; A. faecalis (2 % v/v) was able to grow and effectively degrade 68 % of acrylic paints (1 %)-mended mineral salt medium after 14 d of incubation. The rate of biodegradation was significantly (p< 0.05) increased with increasing the medium concentration, inoculum size, agitation speed and nitrogen sources. The most significant biodegradation efficiencies were obtained at a pH of 7.2, temperature of 37 °C, an agitation speed of 200 rpm, an inoculum concentration of 10 %, paint concentration of 2 %; when yeast extract (10 %) was used as a major nitrogen source. Accordingly, this work provides baseline data for optimum biodegradation of acrylate by A. faecalis, and thus could be possibly exploited as an effective bioremediation agent for acrylic paint polluted sites.

Hospital wastewaters are produced in large volumes in Pakistan (∼362–745 L/bed.day) and are discharged without proper treatment. They are widely used by farmers for crop irrigation and induce a phytotoxic effect on plant growth. The study was conducted to evaluate the effect of untreated and treated hospital wastewater on seed germination of a fodder crop Trifolium alexandrinum (Berseem clover) and a food crop Solanum lycopersicum (tomato). A bacterial consortium was formed with three bacterial strains, i.e., Alcaligenes faecalis and Bacillus paramycoides spp., which were individually proven efficient in previous studies. The concentrations of untreated and treated hospital wastewater (25, 50, 75 and 100%) were used to irrigate these crop seeds. To assess the efficiency of treatment, the germination percentage, delay index, germination index, stress tolerance indices, seedling vigour index and phytotoxicity index were calculated and were statistically proven significant. The seeds grown in treated wastewater concentrations showed negative values of phytotoxicity indices (tomato: −0.36, −0.47, −0.78 and −1.11; Berseem clover: −0.23) which indicate a stimulatory or non-toxic effect on seedling growth. Our work proposes that this bacterial consortium is efficient for hospital wastewater treatment before crop irrigation. HIGHLIGHTS Bacterial consortia proficiently used for hospital wastewater treatment.; Novel combination of Alcaligenes faecalis and Bacillus paramycoides spp. promotes the efficiency of hospital wastewater treatment.; Consortium proved to be capable of phytotoxicity reduction in two crop plants, Trifolium alexandrinum (Berseem clover) and Solanum lycopersicum (tomato), irrigated with treated hospital wastewater concentrations.;

Farmers near towns and cities are using a wide range of highly polluted wastewaters for crop irrigation in Pakistan due to severe freshwater shortage. The present study aimed to promote indigenous bacterial strains isolated from domestic, hospital, textile, pharmaceutical and mixed wastewaters to remove contaminants and colour and render these wastewaters safer for irrigation. Thirty seven bacterial strains were isolated from five wastewater samples collected from different sites in Lahore, Pakistan. Under optimal growth conditions, three isolates (D6, D7 and P1) showed >93% decolourisation potential in the treatment of hospital wastewater. 16S rDNA sequencing identified two of these isolates (D6 and D7) as showing 100% and 99.86% homology to Bacillus paramycoides spp. – novel strains from B. cereus group. Isolate P1 showed 97.47% homology to Alcaligenes faecalis. GCMS analysis of the untreated hospital wastewater revealed the presence of pharmaceutic pollutants, i.e. Phenol (876 µg/L), Salicylic acid (48 µg/L), Caffeine (7 µg/L), Naproxen (23 µg/L), Octadecene (185 µg/L) and Diazepam (14 µg/L). The analysis of treated hospital wastewaters showed percentage degradation of pharmaceutic pollutants (100%–43%) and significant reduction in the BOD5 (91%–68%), COD (89%–52%) and heavy metals concentrations. These strains therefore can represent a low-cost and low-tech alternative to bioremediate complex matrices of hospital wastewater prior to crop irrigation to support the achievement of clean re-usable water in developing countries like Pakistan. [ABSTRACT FROM AUTHOR]

Background: Drug-resistant bacteria are important carriers of antibiotic-resistant genes (ARGs). This fact is crucial for the development of precise clinical drug treatment strategies. Long-read sequencing platforms such as the Oxford Nanopore sequencer can improve genome assembly efficiency particularly when they are combined with short-read sequencing data. Results: Alcaligenes faecalis PGB1 was isolated and identified with resistance to penicillin and three other antibiotics. After being sequenced by Nanopore MinION and Illumina sequencer, its entire genome was hybrid-assembled. One chromosome and one plasmid was assembled and annotated with 4,433 genes (including 91 RNA genes). Function annotation and comparison between strains were performed. A phylogenetic analysis revealed that it was closest to A. faecalis ZD02. Resistome related sequences was explored, including ARGs, Insert sequence, phage. Two plasmid aminoglycoside genes were determined to be acquired ARGs. The main ARG category was antibiotic efflux resistance and β-lactamase (EC 3.5.2.6) of PGB1 was assigned to Class A, Subclass A1b, and Cluster LSBL3. Conclusions: The present study identified the newly isolated bacterium A. faecalis PGB1 and systematically annotated its genome sequence and ARGs. [ABSTRACT FROM AUTHOR]

Ammonia oxidation is an important process in both the natural nitrogen cycle and nitrogen removal from engineered ecosystems. Recently, a new ammonia oxidation pathway termed Dirammox (direct ammonia oxidation, NH3→NH2OH→N2) has been identified in Alcaligenes ammonioxydans. However, whether Dirammox is present in other microbes, as well as its genetic regulation, remains unknown. In this study, it was found that the metabolically versatile bacterium Alcaligenes faecalis strain JQ135 could efficiently convert ammonia into N2 via NH2OH under aerobic conditions. Genetic deletion and complementation results suggest that dnfABC is responsible for the ammonia oxidation to N2 in this strain. Strain JQ135 also employs aerobic denitrification, mainly producing N2O and trace amounts of N2, with nitrite as the sole nitrogen source. Deletion of the nirK and nosZ genes, which are essential for denitrification, did not impair the capability of JQ135 to oxidize ammonia to N2 (i.e., Dirammox is independent of denitrification). Furthermore, it was also demonstrated that pod (which encodes pyruvic oxime dioxygenase) was not involved in Dirammox and that AFA_16745 (which was previously annotated as ammonia monooxygenase and is widespread in heterotrophic bacteria) was not an ammonia monooxygenase. The MocR-family transcriptional regulator DnfR was characterized as an activator of the dnfABC operon with the binding motif 5′-TGGTCTGT-3′ in the promoter region. A bioinformatic survey showed that homologs of dnf genes are widely distributed in heterotrophic bacteria. In conclusion, this work demonstrates that, besides A. ammonioxydans, Dirammox occurs in other bacteria and is regulated by the MocR-family transcriptional regulator DnfR. [ABSTRACT FROM AUTHOR]

This study involved therapeutic targets mining for the extremely drug-resistant bacterial species called Alcaligenes faecalis, which is known to infect humans. The infections caused by this species in different parts of the human body have been linked with a higher degree of resistance to several classes of antibiotics. Meanwhile, alternate therapeutic options are needed to treat these bacterial infections in clinical settings. In the current study, a subtractive proteomics approach was adapted to annotate the whole proteome of Alcaligenes faecalis and prioritize target proteins for vaccine-related therapeutics design. This was followed by targeted protein-specific immune epitope prediction and prioritization. The shortlisted epitopes were further subjected to structural design and in silico validation of putative vaccines against Alcaligenes faecalis. The final vaccine designs were also evaluated for potential interaction analysis with human TLR-2 through molecular docking. Finally, the putative vaccines were subjected to in silico cloning and immune simulation approaches to ensure the feasibility of the target-specific vaccine constructs in further experimental designs. [ABSTRACT FROM AUTHOR]

Quinolinic acid (QA) is a pyridine derivative that can be found in many organisms and is widely used in the chemical industry. However, QA possesses excitotoxic properties. To date, the catabolism of QA mediated by microorganisms has rarely been reported. In this study, a QA-degrading strain (JQ191) was isolated from sewage sludge. Based on phenotypic and 16S rRNA gene phylogenetic analysis, the strain was identified as Alcaligenes faecalis. Strain JQ191 was able to utilize QA as the sole source of carbon and nitrogen for growth. QA-cultured cells of JQ191 completely degrade 200 mg/L QA within 2 days in a mineral salt medium, whereas the LB-cultured cells experienced a 2-day lag period before degrading QA, indicating that the catabolic enzymes involved in QA degradation were induced by QA. 6-Hydroxypicolinic acid (6HPA) was identified as an intermediate of QA degradation by strain JQ191. A 6HPA monooxygenase gene picB was cloned, genetically disrupted, and heterologously expressed, and the results show that picB was responsible for catalyzing 6HPA to 3,6DHPA in JQ191. A new QA mineralization pathway was proposed. This study identifies a new bacterium candidate that has a potential application prospect in the bioremediation of QA-polluted environment, as well as provides new insights into the bacterial catabolism of QA. [ABSTRACT FROM AUTHOR]

Microbial immobilization is considered as one of the effective denitrification techniques in the treatment of high load wastewater. In this study, the immobilized cells consisting of polyvinyl alcohol (PVA), sodium alginate (SA), and calcium chloride (CaCl2) were inoculated with Alcaligenes faecalis strain WT14 to treat wastewater with high nitrate-nitrogen ( NO 3 − -N) concentrations. After 48 h of wastewater treatment, 26.2–89.4% of total nitrogen (TN) was removed by the immobilized Alcaligenes faecalis strain WT14. The response surface methodology revealed the highest TN removal efficiency by Alcaligenes faecalis strain WT14 occurred at the immobilized ratio of 9.3% of PVA, 2.2% of SA and 1.9% of CaCl2. Under the optimal ratio of PVA, SA, and CaCl2, the conditions for the maximum denitrification efficiency and TN removal were pH of 7, temperature of 40°C, and shaking speed of 60 rpm·min−1. Compared to the free cells, the immobilization cells had no obvious negative effect on denitrification efficiency, additionally reduced the nitrite accumulation, and thus improved the TN removal. Furthermore, the immobilized cells still maintained 95.4% of NO 3 − -N removal after the eighth cycle reuse. These results demonstrated the immobilized Alcaligenes faecalis strain WT14 can remove TN effectively and additionally reduce nitrite accumulation in treating high strength NO 3 − -N wastewater. [ABSTRACT FROM AUTHOR]

A strain of Alcaligenes faecalis A12C (A. faecalis A12C) isolated from Argyrosomus regius is a probiotic in fish. Previous experiments showed that A. faecalis A12C had inhibitory effects on the growth of multidrug-resistant bacteria. We aimed to confirm whether A. faecalis A12C is safe and has adequate intestinal colonization in experimental rats, and evaluate its efficacy in an animal model of peritonitis. We used 30 male rats, randomly divided into 6 groups (n = 5): three groups (HA7, HA15, HA30) received A. faecalis A12C in drinking water (6 × 108 CFU/mL) for 7 days, and three control groups received drinking water only. All groups were evaluated at 7, 15, and 30 days. Survival after A. faecalis A12C administration was 100% in all groups. Mild eosinophilia (1.5%, p < 0.01) and increased aspartate aminotransferase (86 IU/L, p < 0.05) were observed in HA7, followed by progressive normalization. No histological signs of organ injury were found. We observed significant E. coli decline in faeces, parallel to an increase in A. faecalis A12C at 7 days. E. coli had a tendency to recover initial values, while A. faecalis A12C disappeared from the intestinal microbiota at 30 days. To evaluate its efficacy against peritonitis, we studied two additional groups of animals: IA group pretreated with A. faecalis A12C before E. coli intra-abdominal inoculation, and IC group inoculated with no A. faecalis A12C. We found an increase in C-reactive protein, alanine aminotransferase, urea, and eosinophils in IC animals when compared with IA. Peritonitis was more evident in IC than in IA animals. Our findings suggest that A. faecalis A12C altered clinically relevant parameters in sepsis and was associated with a lesser spread of infection. [ABSTRACT FROM AUTHOR]

The copious compatible solute dimethylsulfoniopropionate (DMSP) plays significant roles in marine ecosystems. The DMSP degradation pathways in strain Alcaligenes faecalis M3A have been comprehensively studied, in which DMSP was cleaved into dimethyl sulphide (DMS) and acrylate. However, the transcriptional regulatory mechanism of DMSP degradation is not fully elucidated. In this study, the TetR/AcrR family transcriptional regulator DdaR repressing acuI operon in strain M3A was investigated. The transcription start sites and promoters of the acuI and ddaR operons was identified. DdaR bound to both the acuI and ddaR promoter regions in EMSA experiment. Two binding sites of DdaR shared conserved motif 5′-CNNCGTNACGNNG-3′ which was essential for the DdaR binding. DdaR was inhibited from binding to the acuI promoter region by acrylate, which acted as a ligand of DdaR. Site-directed mutagenesis was used to investigate the impact of four key amino acid residues (Y61, K67, E135, and I169) in DdaR, revealing their essential roles in the functioning of DdaR. The findings of this study unveil a negative transcriptional regulation mechanism of DMSP degradation in A. faecalis M3A by DdaR and provide a new understanding of the TetR/AcrR-type transcriptional regulators. • The DdaR-binding region in acuI and ddaR operons' promoter were identified. • The transcription start site and promoter of the acuI and ddaR operons were identified. • Acrylate acting as the possible substrates for DdaR. • The role of four key amino acid residues of DdaR were identified. [ABSTRACT FROM AUTHOR]

A total of 24 morphologically distinct salt-tolerant bacteria were isolated from the tomato rhizosphere soil and tested in vitro against Pythium aphanidermatum, causing damping-off disease in tomato. Among them, five bacterial isolates viz., BTR1.0, BTR1.1, BTR4.4, BTR7.0 and BTR8.6 were found to inhibit the mycelial growth of P. aphanidermatum. The maximum antagonistic effect was shown by BTR1.0 followed by BTR7.0 and BTR1.1. Based on the MALDI Biotyper analysis, these bacterial isolates were identified as Serratia marcescens (BTR1.0 and BTR1.1), Pseudomonas aeruginosa (BTR7.0 and BTR8.6) and Alcaligenes faecalis (BTR4.4). Analysis of plant growth stimulating activity of bacterial strains revealed that A. faecalis BTR4.4 recorded the highest vigour index followed by S. marcescens BTR1.0. The biocontrol activity of bacterial antagonists against tomato damping-off was tested under salt-water irrigation. Among the bacterial strains tested, S. marcescens BTR1.1 was found to be highly effective under non-saline water irrigation, which suppressed the disease by 68% compared to infected control. However, at 50 mM NaCl concentration, S. marcescens strain BTR1.0, P. aeruginosa strain BTR7.0 and A. faecalis BTR4.4 provided a significant level of control of the disease. At 100 mM NaCl concentration, no significant effect of the bacterial strains on the disease incidence was observed.

One hundred and fifty six native bacterial strains with different morphological characters were isolated from water and soil samples collected from textile wastewater effluent sites, Sri Lanka. Three isolated bacterial strains were more effective on decolorization of CI Direct Blue 201 textile dye and 16s rRNA analysis reveals that the bacterial strains were Alcaligenes faecalis (MK166784), Micrococcus luteus (MK166783) and Staphylococcus warneri (MK256311). A. faecalis, M. luteus and S. warneri showed complete decolorization of CI Direct Blue 201 textile dye within 60, 64, and 72 h of incubation time respectively under the static conditions at 28 oC. Decolorization was effective at a temperature range from 24 oC to 40 oC and pH range from 7 to 9. The presence of tryptone, peptone or yeast in the Mineral Salt Medium enhanced the decolorization of the dye. Phytotoxicity assay based on the seed germination percentages of Oryza sativa and Vigna radiate showed that the detoxification of CI Direct Blue 201 textile dye after the bacterial treatment was effective signifying the potential applicability of the A. faecalis, M. luteus and S. warneri to develop a green application to treat textile wastewater.

Alcaligenes spp., including A. faecalis, is a gram-negative facultative bacterium uniquely residing inside the Peyer’s patches. We previously showed that A. faecalis-derived lipopolysaccharides (Alcaligenes LPS) acts as a weak agonist of toll-like receptor 4 to activate dendritic cells and shows adjuvant activity by enhancing IgG and Th17 responses to systemic vaccination. Here, we examined the efficacy of Alcaligenes LPS as a nasal vaccine adjuvant. Nasal immunization with ovalbumin (OVA) plus Alcaligenes LPS induced follicular T helper cells and germinal center formation in the nasopharynx-associated lymphoid tissue (NALT) and cervical lymph nodes (CLNs), and consequently enhanced OVA-specific IgA and IgG responses in the respiratory tract and serum. In addition, nasal immunization with OVA plus Alcaligenes LPS induced OVA-specific T cells producing IL-17 and/or IL-10, whereas nasal immunization with OVA plus cholera toxin (CT) induced OVA-specific T cells producing IFN-γ and IL-17, which are recognized as pathogenic type of Th17 cells. In addition, CT, but not Alcaligenes LPS, promoted the production of TNF-α and IL-5 by T cells. Nasal immunization with OVA plus CT, but not Alcaligenes LPS, led to increased numbers of neutrophils and eosinophils in the nasal cavity. Together, these findings indicate that the benign nature of Alcaligenes LPS is an effective nasal vaccine adjuvant that induces antigen-specific mucosal and systemic immune responses without activation of inflammatory cascade after nasal administration.

Alcaligenes spp., including A. faecalis , is a gram-negative facultative bacterium uniquely residing inside the Peyer's patches. We previously showed that A. faecalis -derived lipopolysaccharides (Alcaligenes LPS) acts as a weak agonist of toll-like receptor 4 to activate dendritic cells and shows adjuvant activity by enhancing IgG and Th17 responses to systemic vaccination. Here, we examined the efficacy of Alcaligenes LPS as a nasal vaccine adjuvant. Nasal immunization with ovalbumin (OVA) plus Alcaligenes LPS induced follicular T helper cells and germinal center formation in the nasopharynx-associated lymphoid tissue (NALT) and cervical lymph nodes (CLNs), and consequently enhanced OVA-specific IgA and IgG responses in the respiratory tract and serum. In addition, nasal immunization with OVA plus Alcaligenes LPS induced OVA-specific T cells producing IL-17 and/or IL-10, whereas nasal immunization with OVA plus cholera toxin (CT) induced OVA-specific T cells producing IFN-γ and IL-17, which are recognized as pathogenic type of Th17 cells. In addition, CT, but not Alcaligenes LPS, promoted the production of TNF-α and IL-5 by T cells. Nasal immunization with OVA plus CT, but not Alcaligenes LPS, led to increased numbers of neutrophils and eosinophils in the nasal cavity. Together, these findings indicate that the benign nature of Alcaligenes LPS is an effective nasal vaccine adjuvant that induces antigen-specific mucosal and systemic immune responses without activation of inflammatory cascade after nasal administration. [ABSTRACT FROM AUTHOR]

BACKGROUND: Drosophila suzukii (Matsumura, 1931) (spotted wing drosophila), an invasive species, has recently become a significant global pest of soft-skinned fruits such as berries. Unlike other Drosophila species, female D. suzukii have evolved a specialized sharp, serrated ovipositor that pierces and penetrates ripe and ripening fruits, causing them to lose commercial value and preventing their sale. A first step for the development of biological control agents for pest management may be achieved through the identification of microbes infectious for D. suzukii in the wild. RESULTS: We first determined that D. suzukii is susceptible to chemicals commonly used to rear Drosophilids in the laboratory and established a diet able to sustain healthy D. suzukii growth. Using this diet, we demonstrated that of 25 species of culturable bacteria and fungi isolated from field-collected D. suzukii, eight microbes decreased host survival when injected. Three of the eight bacteria (Alcaligenes faecalis, Achromobacter spanius and Serratia marcescens) were acutely pathogenic to both D. suzukii and Drosophila melanogaster adults by injection. Feeding of these bacteria resulted in susceptibility only in larvae. CONCLUSION: We successfully identified multiple microbes from field-collected D. suzukii that are pathogenic to both larvae and adults through different routes of infection, some of which could be candidates for biocontrol of this species. [ABSTRACT FROM AUTHOR]

Probiotics are being developed as water additives to stimulate the immune system of fish, and to improve water quality by affecting the microbial communities in the fish and the culture environment. In the present study, the effect of the probiotics Bacillus cereus NY5 and Alcaligenes faecalis Y311 on water quality and microbiota in Nile tilapia tanks, and on the fish themselves, were investigated. The probiotics (1.0 × 104 colony-forming units /mL) were added separately to the experimental tanks every 7 days over a 3-month period. The water quality, environmental and fish microbiota, and immune enzyme activities in the intestine, skin, and gill of tilapia were analyzed. Both probiotics significantly decreased the total phosphorus levels in tank water compared with the control (P

Chlorpyrifos (Chlp), one of the major organophosphates is extensively used in agriculture to control pests. With a half-life of 7–120 d, it may persist for up to one year in soil depending on the soil conditions and affect the soil microflora. Chlp degradation by soil microbes proves to be an effective and environment friendly method to remove it from the soil. This study aims to identify and characterize Chlp degrading soil microbes. Total 173 bacteria isolated from different soil samples were screened for Chlp degradation. Characterization of 10 selected samples showed that all the strains produced excessive exo-polysaccharides (EPSs), which positively correlated with the Chlp degradation under in vitro conditions. Among these 10 bacterial strains, the most potent Chlp degrading bacteria was identified to be Alcaligenes faecalis (NBRI OSS2-5) which paired with the Chlp degrading Pseudomonas in the phylogenetic tree. The strain was shown to possess opd gene reported for Chlp degradation. From the study, it was concluded that EPS production may be a common feature of Chlp degrading microbes which may have some role in the Chlp biodegradation process and the pesticide-contaminated fields may not necessarily be the ideal source of isolating pesticide degrading microbes. [ABSTRACT FROM AUTHOR]

In this study, simultaneous removal of ammonium plus phenol could be achieved by Alcaligenes faecalis strain WY-01 with the addition of acetate, although acetate delayed the phenol degradation, probably due to the delayed expression of phenol hydroxylase gene under the presence of acetate. Moreover, the successful expression of key enzyme genes in strain WY-01 provided some evidence to illustrate its metabolic pathways of ammonium and phenol under aerobic conditions. Furthermore, SEM was used to clarify the role of acetate in resisting phenol toxicity, and these results demonstrated that strain WY-01 has the ability to form cell flocs when sodium acetate is used as co-substrate for a high concentration of phenol, and these flocs could protect cells against the toxicity of phenol, further enhancing phenol degradation in a high concentration of phenol. All these will provide further insights into the efficacy of strain WY-01 for treating wastewater cocontaminated by ammonium and phenol. [ABSTRACT FROM AUTHOR]