Genera Achromobacter Research Articles

ШТАММ ACHROMOBACTER SP 36P ‒ ДЕСТРУКТОР 2,4,5-ТРИХЛОРФЕНОКСИУКСУСНОЙ КИСЛОТЫ

A natural strain isolated from a soil sample from an industrial zone in Ufa was identified. Based on the results of analysis of physiological and biochemical data and the 16S rDNA gene sequence, the taxonomic position of the isolate was determined to the genus Achromobacter. The strain was designated Achromobacter sp 36P. The substrate activity of the culture in relation to 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) was studied. The isolate utilized 2,4,5-T at a concentration of 100 mg/l for 5 days, and a decrease in the amount of substrate by 73% of the initial value was observed.

Bleached Coral Supports High Diversity and Heterogeneity of Bacterial Communities: Following the Rule of the ‘Anna Karenina Principle’

Coral-associated bacteria are sensitive to the health status of coral and proven biomarker(s) of the coral bleaching. However, whether coral specificity or health status play a key role when coral-associated bacteria responding to coral bleaching is not known. Therefore, the bacterial communities of five species of healthy and bleached corals, Acropora millepora, Favites abdita, Galaxea fascicularis, Dipsastraea speciosa and Pocillopora damicornis, were collected along the coast of Sanya, South China Sea and targeted for associated bacterial studies. The relative abundance of the dominant class Gammaproteobacteria tended to be higher in healthy corals, while Alphaproteobacteria were more abundant in bleached corals. Dominant genus Achromobacter demonstrated higher relative abundance in healthy corals (0.675) than in bleached corals (0.151). Most of the bleached corals had high α diversity, β dispersion, heterogeneity and complexity of the co-occurrence network of bacterial communities, which support the ‘Anna Karenina Principle (AKP)’ of diverse in threatened objects and conserved in healthy ones. The bacterial communities in the bleached corals were mostly involved in the selection process, and communities in the healthy corals were involved in the undominated process, which is obtained based on the null model test of β nearest-taxon-index (βNTI) and Bray–Curtis-based Raup–Crick (RCBray). This evidence further confirmed the AKP and revealed that the bacterial communities in the bleached corals were driven by deterministic factors. These findings provide valuable insights into the connection between bacterial and coral status, and the application of the AKP in the changing patterns of bacterial communities during coral bleaching.

Glyphosate-Induced Phosphonatase Operons in Soil Bacteria of the Genus Achromobacter.

Achromobacter insolitus and Achromobacter aegrifaciens, bacterial degraders of the herbicide glyphosate, were found to induce phosphonatase (phosphonoacetaldehyde hydrolase, EC 3.11.1.1) when grown on minimal media with glyphosate as the sole source of phosphorus. The phosphonatases of the strains were purified to an electrophoretically homogeneous state and characterized. The enzymes differed in their kinetic characteristics and some other parameters from the previously described phosphonatases. The phosphonatase of A. insolitus was first revealed to separate into two stable forms, which had similar kinetic characteristics but interacted differently with affinity and ion-exchange resins. The genomes of the investigated bacteria were sequenced. The phosphonatase genes were identified, and their context was determined: the bacteria were shown to have gene clusters, which, besides the phosphonatase operon, included genes for LysR-type transcription activator (substrate sensor) and putative iron-containing oxygenase PhnHD homologous to monooxygenases PhnY and TmpB of marine organophosphonate degraders. Genes of 2-aminoethylphosphonate aminotransferase (PhnW, EC 2.6.1.37) were absent in the achromobacterial phosphonatase operons; instead, we revealed the presence of genes encoding the putative flavin oxidase HpnW. In silico simulation showed 1-hydroxy-2-aminoethylphosphonate to be the most likely substrate of the new monooxygenase, and a number of glycine derivatives structurally similar to glyphosate to be substrates of flavin oxidase.

Achromobacter seleniivolatilans sp. nov. and Buttiauxella selenatireducens sp. nov., isolated from the rhizosphere of selenium hyperaccumulator Cardamine hupingshanesis.

Two Gram-stain-negative bacterial strains, R39T and R73T, were isolated from the rhizosphere soil of the selenium hyperaccumulator Cardamine hupingshanesis in China. Strain R39T transformed selenite into elemental and volatile selenium, whereas strain R73T transformed both selenate and selenite into elemental selenium. Phylogenetic and phylogenomic analyses indicated that strain R39T belonged to the genus Achromobacter, while strain R73T belonged to the genus Buttiauxella. Strain R39T (genome size, 6.68 Mb; G+C content, 61.6 mol%) showed the closest relationship to Achromobacter marplatensis LMG 26219T and Achromobacter kerstersii LMG 3441T, with average nucleotide identity (ANI) values of 83.6 and 83.4 %, respectively. Strain R73T (genome size, 5.22 Mb; G+C content, 50.3 mol%) was most closely related to Buttiauxella ferragutiae ATCC 51602T with an ANI value of 86.4 %. Furthermore, strain A111 from the GenBank database was found to cluster with strain R73T within the genus Buttiauxella through phylogenomic analyses. The ANI and digital DNA-DNA hybridization values between strains R73T and A111 were 97.5 and 80.0% respectively, indicating that they belong to the same species. Phenotypic characteristics also differentiated strain R39T and strain R73T from their closely related species. Based on the polyphasic analyses, strain R39T and strain R73T represent novel species of the genera Achromobacter and Buttiauxella, respectively, for which the names Achromobacter seleniivolatilans sp. nov. (type strain R39T=GDMCC 1.3843T=JCM 36009T) and Buttiauxella selenatireducens sp. nov. (type strain R73T=GDMCC 1.3636T=JCM 35850T) are proposed.

Analysis of the Influence of Oil Pollution on the Bacterial Component of Groundwater in a Karst Region on the Territory of a Long-term Developed Oil Field

The influence of oil pollution of groundwater in a karst region onto the bacterial component was studied. It has been established that bacteria are present in groundwater in an amount of 103–106 cells/ml. Representatives of the genus Arthobacter, Microbacterium, Rhodococcus, Williamsia (phylum Actinobacteria), Achromobacter and Pseudomonas (phylum Proteobacteria), Bacillus and Brevibacteria (phylum Firmicutes) were revealed. The state of the microbial component of the studied groundwater was analyzed according to the scale of environmental modifications. It was concluded that, with the exception of the release of groundwater at a site 320 m away from the oil field facilities, bacteriocenoses are in a state of "anthropogenic ecological stress".

Effects of common artificial sweeteners at environmentally relevant concentrations on soil springtails and their gut microbiota

Artificial sweeteners (AS) are extensively utilized as sugar substitutes and have been recognized as emerging environmental contaminants. While the effect of AS on aquatic organisms has garnered recent attention, their effects on soil invertebrates and gut microbial communities remain unclear. To address this knowledge gap, we exposed springtails (Folsomia candida) to both single and combined treatments of four typical AS (sucralose [SUC], saccharin [SAC], cyclamate [CYC], and acesulfame [ACE]) at environmentally relevant concentrations of 0.01, 0.1 and 1 mg kg−1 in soil. Following the first-generational exposure, the reproduction of juveniles showed a significant increase under all the AS treatments of 0.1 mg kg−1. The transcriptomic analysis revealed significant enrichment of several Kyoto Encyclopedia of Gene and Genome pathways (e.g., glycolysis/gluconeogenesis, pentose and glucuronate interconversions, amino sugar, and nucleotide sugar metabolism, ribosome, and lysosome) in springtails under all AS treatments. Analysis of gut bacterial microbiota indicated that three AS (SUC, CYC, and ACE) significantly decreased alpha diversity, and all AS treatments increased the abundance of the genus Achromobacter. After the sixth-generational exposure to CYC, weight increased, but reproduction was inhibited. The pathways that changed significantly (e.g., extracellular matrix-receptor interaction, amino sugar and nucleotide sugar metabolism, lysosome) were generally similar to those altered in first-generational exposure, but with opposite regulation directions. Furthermore, the effect on the alpha diversity of gut microbiota was contrary to that after first-generational exposure, and more noticeable disturbances in microbiota composition were observed. These findings underscore the ecological risk of AS in soils and improve our understanding of the toxicity effects of AS on living organisms.

Phosphonatase Operons of Organophosphonate-Degrading Soil Bacteria of the Genus Achromobacter

Phosphonatase Operons of Organophosphonate-Degrading Soil Bacteria of the Genus Achromobacter

Identification and characterization of a novel β-lactamase gene, blaAMZ-1, from Achromobacter mucicolens.

Achromobacter is a genus of gram-negative bacteria that can act as opportunistic pathogens. Recent studies have revealed that some species of Achromobacter show inherent resistance to β-lactams, but the resistance mechanisms of Achromobacter mucicolens have rarely been reported. The bacterium was isolated using standard laboratory procedures. The agar dilution method was used to determine the minimum inhibitory concentrations (MICs). Genome sequencing was performed using the PacBio RS II and Illumina HiSeq 2500 platforms, and the Comprehensive Antibiotic Resistance Database (CARD) was used to annotate the drug resistance genes. The localization of the novel β-lactamase AMZ-1 was determined, and its characteristics were determined via molecular cloning and enzyme kinetic analysis. The phylogenetic relationship and comparative genomic analysis of the resistance gene-related sequences were also analyzed. Achromobacter mucicolens Y3, isolated from a goose on a farm in Wenzhou, showed resistance to multiple antibiotics, including penicillins and cephalosporins. BlaAMZ-1 showed resistance to amoxicillin, penicillin G, ampicillin, cephalothin and cefoxitin, and the resistance activity could be inhibited by β-lactamase inhibitors. Enzyme kinetic analysis results showed that AMZ-1 has hydrolytic activity against a wide range of substrates, including cephalothin, amoxicillin, penicillin G, and cefoxitin but not ampicillin. The hydrolytic activity of AMZ-1 was greatly inhibited by avibactam but much more weakly inhibited by tazobactam. Mobile genetic elements could not be found around the blaAMZ-1-like genes, which are conserved on the chromosomes of bacteria of the genus Achromobacter. In this study, a novel AmpC gene, blaAMZ-1, from the animal-origin bacterium A. mucicolens Y3 was identified and characterized. It conferred resistance to some penicillins and first- and second-generation cephalosporins. The identification of this novel resistance gene will be beneficial for the selection of effective antimicrobials to treat associated infections.

Achromobacter denitrificans blood stream infection in adult patients: Clinical and microbiological features from a tertiary care centre in North India

Genus Achromobacter is ubiquitous, opportunistic pathogen. Treating Achromobacter infections are a challenge as the bacterium is intrinsically resistant to several empirically used antibiotics. There is a dearth of data on this organism so; the present prospective study was undertaken to understand various aspects of this uncommon organism.

The Achromobacter type 3 secretion system drives pyroptosis and immunopathology via independent activation of NLRC4 and NLRP3 inflammasomes

How the opportunistic Gram-negative pathogens of the genus Achromobacter interact with the innate immune system is poorly understood. Using three Achromobacter clinical isolates from two species, we show that the type 3 secretion system (T3SS) is required to induce cell death in human macrophages by inflammasome-dependent pyroptosis. Macrophages deficient in the inflammasome sensors NLRC4 or NLRP3 undergo pyroptosis upon bacterial internalization, but those deficient in both NLRC4 and NLRP3 do not, suggesting either sensor mediates pyroptosis in a T3SS-dependent manner. Detailed analysis of the intracellular trafficking of one isolate indicates that the intracellular bacteria reside in a late phagolysosome. Using an intranasal mouse infection model, we observe that Achromobacter damages lung structure and causes severe illness, contingent on a functional T3SS. Together, we demonstrate that Achromobacter species can survive phagocytosis by promoting macrophage cell death and inflammation by redundant mechanisms of pyroptosis induction in a T3SS-dependent manner.

Sequencing of the Whole Genome of a Bacterium of the Genus Achromobacter Reveals Its Potential for Xenobiotics Biodegradation

The isolation of new bacterial strains from the natural environment can lead to the detection of microorganisms of potential practical importance. The characterization of such microorganisms can be carried out using classical microbiological and molecular biology methods. Currently, studies of newly detected microorganisms are based on sequencing techniques. Sequencing of the full genome can provide information about the origin of the strain, its taxonomic status, and phenotypic characteristics. The studies were conducted using the bacteria Achromobacter sp. 77Bb1 isolated from the maize crop rhizosphere. The bacterial genome was sequenced using Illumina 2 × 150 nt technology. The obtained sequences were analyzed using bioinformatics methods, resulting in 57 contigs and genome containing 6,651,432 nt. Phylogenetic analysis based on 16S rRNA gene sequences enabled the assignment of the analyzed bacteria to the genus Achromobacter. The obtained genome contained genes for 4855 proteins with functional assignment. Some of these genes were connected with xenobiotics biodegradation and metabolisms. All genes for aminobenzoate degradation and almost all for benzoate and styrene degradation were found in the analyzed genome, suggesting that the isolated strain has the potential to be used in natural bioremediation methods.

P236 Siderophore production by the emerging cystic fibrosis pathogens of the genus Achromobacter

Achromobacter are opportunistic pathogens increasingly isolated in patients with cystic fibrosis (CF). Despite recent advances, their virulence factors remain incompletely studied. Particularly, ironchelating molecules called siderophores have not yet been studied in CF Achromobacter isolates although being major bacterial virulence factors. The aims of our study were: I) to characterize the production of siderophores by Achromobacter spp. isolated from CF patients, II) to compare results to strains from non-CF patients to search for specific virulence characteristics that may be observed in the CF context.

Achromobacter xylosoxidans as emerging pathogen in healthcare settings: A mini review

Microorganisms of the genus Achromobacter have been mentioned as a cause of opportunistic infections, mainly in patients with cystic fibrosis or pulmonary lymphoma, with the species Achromobacter xylosoxidans being identified to a large extent. A. xylosoxidans was first described in 1971 and is an opportunistic pathogen. However, it been reported to cause chronic purulent otitis, meningitis, pneumonia, peritonitis and urinary tract infections, chronic obstructive pulmonary disease and other infections. The present literature review aims to analyze and synthesize the state of the art on A. xylosoxidans and its potential as an emerging pathogen in the healthcare settings. We discuss A. xylosoxidans as an emerging opportunistic pathogen that is associated with healthcare infections. This review further discusses the prevalence of A. xylosoxidans in healthcare settings, the types of infections it can cause, and the risk factors for acquiring an A. xylosoxidans infection. The review also covers the challenges in treating A. xylosoxidans infections, including its potential for drug resistance and the lack of specific treatments. Strategies for preventing and controlling A. xylosoxidans infections in healthcare settings were also discussed.

Characterization of the Achromobacter xylosoxidans Type VI Secretion System and Its Implication in Cystic Fibrosis.

Bacteria of the genus Achromobacter are environmental germs, with an unknown reservoir. It can become opportunistic pathogens in immunocompromised patients, causing bacteremia, meningitis, pneumonia, or peritonitis. In recent years, Achromobacter xylosoxidans has emerged with increasing incidence in patients with cystic fibrosis (CF). Recent studies showed that A. xylosoxidans is involved in the degradation of the respiratory function of patients with CF. The respiratory ecosystem of patients with CF is colonized by bacterial species that constantly fight for space and access to nutrients. The type VI secretion system (T6SS) empowers this constant bacterial antagonism, and it is used as a virulence factor in several pathogenic bacteria. This study aimed to investigate the prevalence of the T6SS genes in A. xylosoxidans isolated in patients with CF. We also evaluated clinical and molecular characteristics of T6SS-positive A. xylosoxidans strains. We showed that A. xylosoxidans possesses a T6SS gene cluster and that some environmental and clinical isolates assemble a functional T6SS nanomachine. A. xylosoxidans T6SS is used to target competing bacteria, including other CF-specific pathogens. Finally, we demonstrated the importance of the T6SS in the internalization of A. xylosoxidans in lung epithelial cells and that the T6SS protein Hcp is detected in the sputum of patients with CF. Altogether, these results suggest for the first time a role of T6SS in CF-lung colonization by A. xylosoxidans and opens promising perspective to target this virulence determinant as innovative theranostic options for CF management.

Microplastics impact the accumulation of metals in earthworms by changing the gut bacterial communities

Microplastics (MPs) are defined as plastic debris with particle size smaller than 5 mm, which have been frequently detected in environments. In this study, earthworms (Eisenia foetida) were exposed to three different sized polystyrene (PS; 0.1, 10 and 100 μm) at 10 and 100 mg per kg soil for 21 days. We examined the contents of metals (Cu, Zn, Ni and Pb) and gut microbial communities in earthworms exposed to MPs. Results showed that MPs reduced the accumulation of Ni and Pb in earthworms on the 21st day. The composition of gut bacterial communities was altered in earthworms exposed to MPs, especially 10 μm MPs, featuring a higher relative abundance of Proteobacteria (44.5%) and Bacteroidetes (27.1%) than the control group. Additionally, gut microorganisms including genus Paenibacillus and Achromobacter in earthworms were expected to be potential biomarkers for Cu and Zn. The microbial community networks showed that MPs affected bacterial community connections by size effect, and MPs with smaller size increased the complexity of earthworm microbial community networks. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that metabolism was the main difference in the bacterial communities in different treatments, especially carbohydrate metabolism and amino acid metabolism, which was relevant to the survival and growth of bacteria. This study provides insight into the environmental risks of MPs on terrestrial organisms.

Infecciones por microorganismos del grupo HACEK y otros bacilos gramnegativos infrecuentes

There are a multitude of uncommon Gram-negative bacilli (GNB) capable of causing various infections in human beings; it is an extremely heterogeneous group of pathogens. Of note are those known as HACEK (Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, and Kingella) group GNB. They are slow-growing bacteria that are an infrequent cause of infective endocarditis with a subacute course and embolic complications. The majority are oral flora, causing infection following dental procedures. New microbiological techniques such as better culture media, MALDI-TOF, or molecular techniques such as DNA sequencing or the use of 16S rRNA PCR represent advances in their diagnosis. Treatment for them varies; amoxicillin-clavulanic acid or third-generation cephalosporins tend to be used. Of the uncommon non-HACEK GNB, the majority are ubiquitous bacteria that contaminate water and hospital surfaces, giving rise to nosocomial outbreaks of infections, including pneumonias, catheter-associated bacteremias, and other device-related infections. Of note are the genera Achromobacter, Alcaligenes, Chryseobacterium, and Elizabethkingia. Some genera, such as Actinobacillus, Aeromonas, or Chromobacterium, can give rise to infections following exposure to dirty water. Capnocytophaga and Pasteurella can produce infections following animal bites. Their treatment varies and tends to be based on beta-lactams with beta-lactamase inhibitors.

Микробиологический мониторинг хронической инфекции легких, вызванной Achromobacter spp., у пациентов с муковисцидозом

Objective. To provide a rationale for microbiological monitoring of chronic lung infection caused by Achromobacter spp. in patients with cystic fibrosis (CF) to develop an adequate preventive and therapeutic strategy. Materials and methods. This study included 142 Achromobacter strains isolated from 55 children and 35 adults with CF during their follow-up. In this study, classical microbiological (culture) and modern molecular genetic methods (polymerase chain reaction (PCR), multilocus sequence typing (MLST) and whole-genome sequencing (WGS)), and MALDI-TOF-MS were used. Results. Among the examined patients with chronic lung infection caused by bacteria from the genus Achromobacter, monoinfection was detected in 5.8% of patients. In other cases, associations of Achromobacter spp. with other bacterial species were observed. A. ruhlandii (76%) and A. xylosoxidans (7.2%) were the most frequently isolated species. It was shown that the microbiota in CF patients with chronic lung infection caused by Achromobacter spp. is characterized by variability and is related to long-term circulation of both one genotype with different subpopulation phenotypes and circulation of 2 or more genotypes or species of Achromobacter spp., which has clinical and epidemiological significance. Conclusion. Successful prevention and treatment of Achromobacter spp.-associated infections in CF patients require continuous microbiological monitoring of chronic infection, including that of phenotypic and genotypic properties of Achromobacter spp. strains isolated from patients. Key words: chronic lung infection, Achromobacter sp., microbiological monitoring, genotypic and phenotypic heterogeneity, sensitivity to antibiotics

In Vitro Activity of 22 Antibiotics against Achromobacter Isolates from People with Cystic Fibrosis. Are There New Therapeutic Options?

Bacteria belonging to the genus Achromobacter are increasingly isolated from respiratory samples of people with cystic fibrosis (PWCF). The management of this multidrug-resistant genus is challenging and characterised by a lack of international recommendations, therapeutic guidelines and data concerning antibiotic susceptibility, especially concerning the newer antibiotics. The objective of this study was to describe the antibiotic susceptibility of Achromobacter isolates from PWCF, including susceptibility to new antibiotics. The minimum inhibitory concentrations (MICs) of 22 antibiotics were determined for a panel of 23 Achromobacter isolates from 19 respiratory samples of PWCF. Two microdilution MIC plates were used: EUMDROXF® plate (Sensititre) and Micronaut-S Pseudomonas MIC® plate (Merlin) and completed by a third method if necessary (E-test® or UMIC®). Among usual antimicrobial agents, the most active was imipenem (70% susceptibility). Trimethoprim-sulfamethoxazole, piperacillin and tigecycline (65%, 56% and 52% susceptibility, respectively) were still useful for the treatment of Achromobacter infections. Among new therapeutic options, β-lactams combined with a β-lactamase-inhibitor did not bring benefits compared to β-lactam alone. On the other hand, cefiderocol appeared as a promising therapeutic alternative for managing Achromobacter infections in PWCF. This study provides the first results on the susceptibility of clinical Achromobacter isolates concerning new antibiotics. More microbiological and clinical data are required to establish the optimal treatment of Achromobacter infections.

Arsenite-oxidizing bacteria isolated from an abandoned realgar mining area: Characterization and the influence on arsenic accumulation in rice seedlings

Rice consumption is the main route of human exposure to arsenic (As) contamination. Oxidation of more toxic arsenite [As(III)] to less toxic arsenate [As(V)] is considered as a potential strategy to alleviate As contamination in rice plant. In this study, two As(III)-oxidizing bacterial strains SMS06 and SMS11 were isolated from the As-contaminated soils collected from an abandoned realgar mining area in Shimen County, China. According to the 16S rRNA gene sequences, SMS06 and SMS11 were affiliated with genera Achromobacter and Pseudomonas, respectively. The aioA gene was amplified in both strains while the arsB and arsM genes were not detected, indicating that the detoxification of As(III) in the strains was mainly through oxidation process governed by the aioA gene. Under aerobic condition, strains SMS06 and SMS11 could completely oxidize 600 and 450 mg/L of As(III) to As(V), respectively. The oxidation process was dependent on the bacterial growth rate. Reduction of As accumulation was observed in the rice seedlings inoculated with strain SMS06 or SMS11. The total As concentrations in the rice seedlings inoculated with the strains were decreased up to 42.0% compared to that without bacteria inoculation. The results indicated these microorganisms as potential candidates for remediation of As(III) contamination in the environment.

Biodegradation performance and diversity of enriched bacterial consortia capable of degrading high-molecular-weight polycyclic aromatic hydrocarbons

ABSTRACT Polycyclic aromatic hydrocarbons (PAHs) are key organic pollutants in the environment that pose threats to the ecosystem and human health. The degradation of high molecular weight (HMW) PAHs by enriched bacterial consortia has been previously studied, while the involved metabolisms and microbial communities are still unclear and warrant further investigations. In this study, five bacterial consortia capable of utilizing different PAHs (naphthalene, anthracene, and pyrene) as the sole carbon and energy sources were enriched from PAH-contaminated soil samples. Among the five consortia, consortium TC exhibited the highest pyrene degradation efficiency (91%) after 19 d of incubation. The degradation efficiency was further enhanced up to 99% by supplementing yeast extract. Besides, consortium TC showed tolerances to high concentrations of pyrene (up to 1000 mg/L) and different heavy metal stresses (including Zn2+, Cd2+, and Pb2+). The dominant genus in consortium TC, GS, and PL showing relatively higher degradation efficiency for anthracene and pyrene was Pseudomonas, whereas consortium PG and GD were predominated by genus Achromobacter and class Enterobacteriaceae, respectively. Consortium TC, as a highly efficient HMW PAH-degrading consortium, could be applied for synergistic biodegradation of HMW PAHs and in situ bioremediation of the sites contaminated with both PAHs and heavy metals.