Transcriptome analysis of the degradation process of organic nitrogen by two heterotrophic nitrifying and aerobic denitrifying bacteria.

The heterotrophic nitrification aerobic denitrification bacteria (HNDS) can perform nitrification and denitrification at the same time. Two HNDS strains, Achromobacter sp. HNDS-1 and Enterobacter sp. HNDS-6 which exhibited an amazing ability to solution nitrogen (N) removal have been successfully isolated from paddy soil in our lab. When peptone or ammonium sulfate as sole N source, no significant difference in gene expression related to nitrification and denitrification of the strains was found according to the transcriptome analysis. The expression of phosphomethylpyrimidine synthase (thiC), ABC transporter substrate-binding protein, branched-chain amino acid ABC transporter substrate-binding protein, and RNA polymerase (rpoE) in HNDS-1 were significantly upregulated when used peptone as N source, while the expression of exopolysaccharide production protein (yjbE), RNA polymerase (rpoC), glutamate synthase (gltD) and ABC-type branched-chain amino acid transport systems in HNDS-6 were significantly upregulated. This indicated that these two strains are capable of using organic N and converting it into NH4+-N, then utilizing NH4+-N to synthesize amino acids and proteins for their own growth, and strain HNDS-6 can also remove NH4+-N through nitrification and denitrification.

Cefiderocol susceptibility of Achromobacter spp.: study of an accurately identified collection of 230 strains.

BACKGROUND: Achromobacter spp. are opportunistic pathogens, mostly infecting immunocompromised patients and patients with cystic fibrosis (CF) and considered as difficult-to-treat pathogens due to both intrinsic resistance and the possibility of acquired antimicrobial resistance. Species identification remains challenging leading to imprecise descriptions of resistance in each taxon. Cefiderocol is a broad-spectrum siderophore cephalosporin increasingly used in the management of Achromobacter infections for which susceptibility data remain scarce. We aimed to describe the susceptibility to cefiderocol of a collection of Achromobacter strains encompassing different species and isolation sources from CF or non-CF (NCF) patients. METHODS: We studied 230 Achromobacter strains (67 from CF, 163 from NCF patients) identified by nrdA gene-based analysis, with available susceptibility data for piperacillin-tazobactam, meropenem and trimethoprim-sulfamethoxazole. Minimal inhibitory concentrations (MICs) of cefiderocol were determined using the broth microdilution reference method according to EUCAST guidelines. RESULTS: Strains belonged to 15 species. A. xylosoxidans represented the main species (71.3%). MICs ranged from ≤ 0.015 to 16 mg/L with MIC50/90 of ≤ 0.015/0.5 mg/L overall and 0.125/2 mg/L against 27 (11.7%) meropenem-non-susceptible strains. Cefiderocol MICs were not related to CF/NCF origin or species although A. xylosoxidans MICs were statistically lower than those of other species considered as a whole. Considering the EUCAST non-species related breakpoint (2 mg/L), 228 strains (99.1%) were susceptible to cefiderocol. The two cefiderocol-resistant strains (A. xylosoxidans from CF patients) represented 3.7% of meropenem-non-susceptible strains and 12.5% of MDR strains. CONCLUSIONS: Cefiderocol exhibited excellent in vitro activity against a large collection of accurately identified Achromobacter strains, irrespective of species and origin.

Achromobacter veterisilvae sp. nov., from a mixed hydrogen-oxidizing bacteria enrichment reactor for microbial protein production.

Strain LMG 30378T was isolated from a hydrogen-oxidizing bacteria enrichment reactor inoculated with forest soil. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that this strain belonged to the genus Achromobacter. Multilocus sequence analysis combined with sequence analysis of a 765 bp nrd A gene fragment both showed Achromobacter agilis LMG 3411T and Achromobacter denitrificans LMG 1231T to be the closest-related neighbours to strain LMG 30378T. Genome sequence analysis revealed a draft genome of 6.81 Mb with a G+C content of 67.2 mol%. In silico DNA-DNA hybridization with A. denitrificans LMG 1231T and A. agilis LMG 3411T showed 42.7 and 42.5% similarity, respectively, confirming that strain LMG 30378T represented a novel Achromobacter species. Phenotypic and metabolic characterization revealed acid phosphatase activity and the absence of phosphoamidase activity as distinctive features. The draft genome composes all necessary metabolic components to fix carbon dioxide and to oxidize molecular hydrogen, suggesting that strain LMG 30378T is a key organism in the enrichment reactor. Together, these data demonstrate that strain LMG 30378T represents a novel species of the genus Achromobacter, for which the name Achromobacter veterisilvae sp. nov. is proposed. The type strain is LMG 30378T (=CCUG 71558T).

Diversity of Achromobacter species recovered from patients with cystic fibrosis, in Argentina.

Different phenotype-based techniques and molecular tools were used to describe the distribution of different Achromobacter species in patients with cystic fibrosis (CF) in Argentina, and to evaluate their antibiotic resistance profile. Phenotypic identification was performed by conventional biochemical tests, commercial galleries and MALDI-TOF MS. Genetic approaches included the detection of A. xylosoxidans specific marker blaoxa-114, the amplification and sequencing of the 16S rRNA gene, nrdA and blaOXA complete sequence, and MLST analysis. Phenotypic approaches, even MALDI-TOF, rendered inconclusive or misleading results. On the contrary, concordant results were achieved with the nrdA sequencing or sequence type (ST) analysis, and the complete blaOXA sequencing, allowing a reliable discrimination of different Achromobacter species. A. xylosoxidans accounted for 63% of Achromobacter infections and A. ruhlandii accounted for 17%. The remaining species corresponded to A. insuavis, A. dolens, A. marplatensis and A. pulmonis. Antimicrobial susceptibilities were determined by the agar dilution method according to CLSI guidelines. Piperacillin, piperacillin/tazobactam and carbapenems were the most active antibiotics. However, the emergence of carbapenem-resistant isolates was detected. In conclusion, prompt and accurate identification tools were necessary to determine that different Achromobacter species may colonize/infect the airways of patients with CF. Moreover, antimicrobial therapy should be administered based on the susceptibility profile of individual Achromobacter sp. isolates.

Cystic fibrosis pathogens survive for extended periods within cough-generated droplet nuclei.

The airborne route is a potential pathway in the person-to-person transmission of bacterial strains among cystic fibrosis (CF) populations. In this cross-sectional study, we investigate the physical properties and survival of common non-Pseudomonas aeruginosa CF pathogens generated during coughing. We conclude that Gram-negative bacteria and Staphylococcus aureus are aerosolised during coughing, can travel up to 4 m and remain viable within droplet nuclei for up to 45 min. These results suggest that airborne person-to-person transmission is plausible for the CF pathogens we measured.

Achromobacter spp. healthcare associated infections in the French West Indies: a longitudinal study from 2006 to 2016.

BACKGROUND: Bacteria of the Achromobacter genus, more particularly xylosoxidans species, are responsible for various healthcare associated infections (HAI) which are increasingly described since the last decade. Cystic fibrosis (CF) patients are considered as potential reservoirs in hospitals. We performed a retrospective study to estimate the frequencies of Achromobacter spp. HAI among patients from French West Indies, to determine characteristics of infected patients and establish a possible link between CF and infections. METHODS: All adults with at least one Achromobacter spp. positive sample and infection criteria in accordance with European official definitions of HAI, hospitalized in University Hospital of Martinique from 2006 to 2016 for more than 48 h, were included. Patient clinical features, immune status and underlying diseases were obtained from medical files. A list of CF patients was given by clinicians. Antibiotic-susceptibility profiles of the strains were determined using an automated method. RESULTS: Mean incidence density was 0.038/1000 days of hospitalization. Achromobacter spp. HAI evolved as an endemic situation with a low but pretty much stable incidence rate over the 11-year observation period. An epidemic peak was noticed in 2013. Among the 66 included patients, 56.1% were immunocompetent and no one had CF. Pneumonia and bacteraemia were the two main HAI. Among the 79 isolated strains, 92.4% were resistant to at least 1 major antibiotic and 16.4% met the definition of multidrug-resistant bacteria. CONCLUSIONS: This microorganism, little known in our country because of the scarcity of CF patients, represents a threat for both immunosuppressed and immunocompetent patients and a therapeutic challenge because of its high resistance.

The Curious Case of Achromobacter eurydice, a Gram-Variable Pleomorphic Bacterium Associated with European Foulbrood Disease in Honeybees.

Honeybees are prone to parasite and pathogen infestations/infections due to their social colony life. Bacterial pathogens in particular lead to destructive infections of the brood. European foulbrood is caused by the bacterium Melissococcus plutonius in combination with several other Gram-positive bacteria (Achromobacter eurydice, Bacillus pumilus, Brevibacillus laterosporus, Enterococcus faecalis, Paenibacillus alvei, Paenibacillus dendritiformis) involved as secondary invaders following the initial infection. More than a century ago, A. eurydice was discovered to be associated with European foulbrood and morphologically and biochemically characterized. However, since the 1950s-1960s, only a few studies are known covering the biological relevance of this bacterium. Here, we review the biology, ecology, morphology, and biochemistry and discuss the still unclear systematic classification of A. eurydice.

Impact of High Diversity of Achromobacter Populations within Cystic Fibrosis Sputum Samples on Antimicrobial Susceptibility Testing.

Chronic colonization by opportunistic environmental bacteria is frequent in the airways of cystic fibrosis (CF) patients. Studies of Pseudomonas aeruginosa evolution during persistence have highlighted the emergence of pathoadaptive genotypes and phenotypes, leading to complex and diversified inpatient colonizing populations also observed at the intraspecimen level. Such diversity, including heterogeneity in resistance profiles, has been considered an adaptive strategy devoted to host persistence. Longitudinal genomic diversity has been shown for the emergent opportunistic pathogen Achromobacter, but phenotypic and genomic diversity has not yet been studied within a simple CF sputum sample. Here, we studied the genomic diversity and antimicrobial resistance heterogeneity of 132 Achromobacter species strains (8 to 27 strains of identical or distinct colonial morphotypes per specimen) recovered from the sputum samples of 9 chronically colonized CF patients. We highlighted the high within-sample and within-morphotype diversity of antimicrobial resistance (disk diffusion) and genomic (pulsed-field gel electrophoresis) profiles. No sputum sample included strains with identical pulsotypes or antibiotic susceptibility patterns. Differences in clinical categorization were observed for the 9 patients and concerned 3 to 11 antibiotics, including antibiotics recommended for use against Achromobacter Within-sample antimicrobial resistance heterogeneity, not predictable from colonial morphology, suggested that it may represent a selective advantage against antibiotics in an Achromobacter persisting population and potentially compromise the antibiotic management of CF airway infections.

Prevalence and Outcomes of Achromobacter Species Infections in Adults with Cystic Fibrosis: a North American Cohort Study.

Achromobacter species are increasingly being detected in cystic fibrosis (CF) patients, with an unclear epidemiology and impact. We studied a cohort of patients attending a Canadian adult CF clinic who had positive sputum cultures for Achromobacter species in the period from 1984 to 2013. Infection was categorized as transient or persistent (≥50% positive cultures for 1 year). Those with persistent infection were matched 2:1 with age-, sex-, and time-matched controls without a history of Achromobacter infection, and mixed-effects models were used to assess pulmonary exacerbation (PEx) frequency and lung function decline. Isolates from a biobank were retrospectively assessed, identified to the species level by nrdA sequencing, and genotyped using pulsed-field gel electrophoresis (PFGE). Thirty-four patients (11% of those in our clinic), with a median age of 24 years (interquartile range [IQR], 20.3 to 29.8 years), developed Achromobacter infection. Ten patients (29%) developed persistent infection. Persistence did not denote permanence, as most patients ultimately cleared infection, often after years. Patients were more likely to experience PEx at incident isolation than at prior or subsequent visits (odds ratio [OR], 2.7 [95% confidence interval {CI}, 1.2 to 6.7]; P = 0.03). Following persistent infection, there was no difference in annual lung function decline (-1.08% [95% CI, -2.73 to 0.57%] versus -2.74% [95% CI, -4.02 to 1.46%]; P = 0.12) or the odds of PEx (OR, 1.21 [95% CI, 0.45 to 3.28]; P = 0.70). Differential virulence among Achromobacter species was not observed, and no cases of transmission occurred. We demonstrated that incident Achromobacter infection was associated with a greater risk of PEx; however, neither transient nor chronic infection was associated with a worsened long-term prognosis. Large, multicenter studies are needed to clarify the clinical impact, natural history, and transmissibility of Achromobacter.

Achromobacter aloeverae sp. nov., isolated from the root of Aloe vera (L.) Burm.f.

Two Gram-staining-negative, strictly aerobic, rod-shaped bacteria, designated strains AVA-1T and AVA-2, were isolated from the root of Aloe vera (L.) Brum.f. derived from Chachoengsao Province, Thailand. The strains contained cytochrome oxidase and catalase activities. They grew in 4 % (w/v) NaCl, at a pH range of 6.0-9.0 (optimally at pH 7) and at 20-42 °C (optimally at 30-37 °C). The major isoprenoid quinone was ubiquinone with eight isoprene units (Q-8). The major fatty acids were C16 : 0 and C17 : 0 cyclo. On the basis of 16S rRNA gene sequence analysis, the strains represent a species belonging to the genus Achromobacter and are closely related to Achromobacter xylosoxidans NBRC 15126T (98.80 %), Achromobacter insolitus LMG 6003T (98.64 %), Achromobacter aminicus LMG 26690T (98.59 %), Achromobacter pulmonis LMG 26696T (98.58 %) and Achromobacter insuavis LMG 26845T (98.58 %). The DNA G+C content of strain AVA-1T was 66.5 mol%. The novel strains had low DNA-DNA relatedness values with related type strains. On the basis of the phenotypic and genotypic data obtained, the strains clearly represent a novel species, for which the name Achromobacter aloeverae sp. nov. is proposed. The type strain is strain AVA-1T (=LMG 29108T=NBRC 111463T=PCU 352T=TISTR 2383T).

Patterns of virulence factor expression and antimicrobial resistance in Achromobacter xylosoxidans and Achromobacter ruhlandii isolates from patients with cystic fibrosis.

Achromobacter spp. are opportunistic pathogens increasingly recovered from adult patients with cystic fibrosis (CF). We report the characterization of 122 Achromobacter spp. isolates recovered from 39 CF patients by multilocus sequence typing, virulence traits, and susceptibility to antimicrobials. Two species, A. xylosoxidans (77%) and A. ruhlandii (23%) were identified. All isolates showed a similar biofilm formation ability, and a positive swimming phenotype. By contrast, 4·3% and 44·4% of A. xylosoxidans and A. ruhlandii, respectively, exhibited a negative swarming phenotype, making the swimming and swarming abilities of A. xylosoxidans significantly higher than those of A. ruhlandii. A. xylosoxidans isolates from an outbreak clone also exhibited significantly higher motility. Both species were generally susceptible to ceftazidime, ciprofloxacin, imipenem and trimethoprim/sulphamethoxazole and there was no significant difference in susceptibility between isolates from chronic or sporadic infection. However, A. xylosoxidans isolates from chronic and sporadic cases were significantly more resistant to imipenem and ceftazidime than isolates of the outbreak clone.

Biodegradation of the Herbicide 2,4-Dichlorophenoxyacetic Acid by a New Isolated Strain of Achromobacter sp. LZ35.

In this study, a bacterial strain of Achromobacter sp. LZ35, which was capable of utilizing 2,4-dichlorophenoxyacetic acid (2,4-D) and 2-methyl-4-chlorophenoxy acetic acid (MCPA) as the sole sources of carbon and energy for growth, was isolated from the soil in a disused pesticide factory in Suzhou, China. The optimal 2,4-D degradation by strain LZ35 occurred at 30 °C and pH 8.0 when the initial 2,4-D concentration was 200 mg L-1. Strain LZ35 harbored the conserved 2,4-D/alpha-ketoglutarate dioxygenase (96%) and 2,4-dichlorophenol hydroxylase (99%), and catabolized 2,4-D via the intermediate 2,4-dichlorophenol. The inoculation of 7.8 × 106 CFU g-1 soil of strain LZ35 cells to 2,4-D-contaminated soil could efficiently remove over 75 and 90% of 100 and 50 mg L-1 2,4-D in 12 days and significantly released the phytotoxicity of maize caused by the 2,4-D residue. This is the first report of an Achromobacter sp. strain that was capable of mineralizing both 2,4-D and MCPA. This study provides us a promising candidate for its application in the bioremediation of 2,4-D- or MCPA-contaminated sites.

Biodegradation of 5-chloro-2-picolinic acid by novel identified co-metabolizing degrader Achromobacter sp. f1.

Several bacteria have been isolated to degrade 4-chloronitrobenzene. Degradation of 4-chloronitrobenzene by Cupriavidus sp. D4 produces 5-chloro-2-picolinic acid as a dead-end by-product, a potential pollutant. To date, no bacterium that degrades 5-chloro-2-picolinic acid has been reported. Strain f1, isolated from a soil polluted by 4-chloronitrobenzene, was able to co-metabolize 5-chloro-2-picolinic acid in the presence of ethanol or other appropriate carbon sources. The strain was identified as Achromobacter sp. based on its physiological, biochemical characteristics, and 16S rRNA gene sequence analysis. The organism completely degraded 50, 100 and 200 mg L-1 of 5-chloro-2-picolinic acid within 48, 60, and 72 h, respectively. During the degradation of 5-chloro-2-picolinic acid, Cl- was released. The initial metabolic product of 5-chloro-2-picolinic acid was identified as 6-hydroxy-5-chloro-2-picolinic acid by LC-MS and NMR. Using a mixed culture of Achromobacter sp. f1 and Cupriavidus sp. D4 for degradation of 4-chloronitrobenzen, 5-chloro-2-picolinic acid did not accumulate. Results infer that Achromobacter sp. f1 can be used for complete biodegradation of 4-chloronitrobenzene in remedial applications.

Effect of High-Dose Antimicrobials on Biofilm Growth of Achromobacter Species Isolated from Cystic Fibrosis Patients.

MICs and biofilm inhibitory concentrations (BICs) were measured for 68 cystic fibrosis (CF) Achromobacter isolates for amikacin, aztreonam, colistin, levofloxacin, and tobramycin. With the exception of colistin and levofloxacin, the remaining antibiotics had MIC90s, BICs at which 50% of the isolates were susceptible (BIC50s), and BICs at which 90% of the isolates were susceptible (BIC90s) equal to or above the highest concentrations tested. In a biofilm model, tobramycin was able to significantly increase killing of bacterial cells compared to controls, for intermediate-resistant strains only, at concentrations of 1,000 and 2,000 µg/ml.

Key high molecular weight PAH-degrading bacteria in a soil consortium enriched using a sand-in-liquid microcosm system.

A novel biphasic system containing mineral medium and sand coated with a biologically weathered creosote-PAH mixture was developed to specifically enrich the high molecular weight polycyclic aromatic hydrocarbon (HMW PAH)-degrading community from a creosote-polluted soil. This consortium (UBHP) removed 70% of the total HMW PAHs and their alkyl-derivatives in 12 weeks. Based on a combined culture-dependent/independent approach, including clone library analysis, detection of catabolic genes, metabolomic profiles, and characterization of bacterial isolates, 10 phylotypes corresponding to five major genera (Sphingobium, Sphingomonas, Achromobacter, Pseudomonas, and Mycobacterium) were pointed out as key players within the community. In response to exposure to different single PAHs, members of sphingomonads were associated to the utilization of phenanthrene, fluoranthene, benzo[a]anthracene, and chrysene, while the degradation of pyrene was mainly associated to low-abundance mycobacteria. In addition to them, a number of uncultured phylotypes were detected, being of special relevance a group of Gammaproteobacteria closely related to a group previously associated with pyrene degradation that were here related to benzo(a)anthracene degradation. The overall environmental relevance of these phylotypes was confirmed by pyrosequencing analysis of the microbial community shift in the creosote-polluted soil during a lab-scale biostimulation.

Draft genome sequences of four Achromobacter ruhlandii strains isolated from cystic fibrosis patients.

Achromobacter species are being increasingly isolated from the respiratory tract of cystic fibrosis patients. Recent reports indicate that Achromobacter ruhlandii is a potential human pathogen in cystic fibrosis-related infections. Here we report the draft genome of four A. ruhlandii strains isolated from cystic fibrosis patients in Brazil. This report describes A. ruhlandii as a potential opportunistic pathogen in cystic fibrosis and provides a framework to for additional enquires into potential virulence factors and resistance mechanisms within this species.

Quinoline-degrading strain Pseudomonas aeruginosa KDQ4 isolated from coking activated sludge is capable of the simultaneous removal of phenol in a dual substrate system.

Quinoline is a refractory organic compound in the treatment of coking wastewater. The isolation of high efficiency quinoline-degrading bacteria from activated sludge and the evaluation of their degradation characteristics in the presence of phenol or in the actual coking wastewater are important for the improvement of effluent quality. The novel bacterial strain Pseudomonas aeruginosa KDQ4 was isolated from a quinoline enrichment culture obtained from the activated sludge of a coking wastewater treatment plant. The optimum temperature and initial pH for quinoline degradation were 33-38°C and 8-9, respectively. KDQ4 completely degraded 400 mg/L of quinoline within 24 h and 800 mg/L of phenol within 30 h. In the dual-substrate system, the removal efficiencies of quinoline and phenol at the same initial concentration (200 mg/L) by KDQ4 were 89% and 100% within 24 h, respectively, indicating that KDQ4 could simultaneously and quickly degrade quinoline and phenol in a coexistence system. Moreover, KDQ4 was able to adapt to actual coking wastewater containing high quinoline and phenol concentrations and rapidly remove them. KDQ4 also exhibited heterotrophic nitrification and aerobic denitrification potential under aerobic conditions. These results suggested a potential bioaugmentation role for KDQ4 in the removal of nitrogen-heterocyclic compounds and phenolics from coking wastewater.

Characterization of Achromobacter Species in Cystic Fibrosis Patients: Comparison of bla(OXA-114) PCR Amplification, Multilocus Sequence Typing, and Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry.

Molecular methodologies were used to identify 28 Achromobacter spp. from patients with cystic fibrosis (CF). Multilocus sequence typing (MLST) identified 17 Achromobacter xylosoxidans isolates (all bla(OXA-114) positive), nine Achromobacter ruhlandii isolates (all bla(OXA-114) positive), one Achromobacter dolens isolate, and one Achromobacter insuavis isolate. All less common species were misidentified as A. xylosoxidans by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Chronic colonization by clonally related A. ruhlandii isolates was demonstrated.

Pseudomonas aeruginosa and Achromobacter sp. clonal selection leads to successive waves of contamination of water in dental care units.

Dental care unit waterlines (DCUWs) consist of complex networks of thin tubes that facilitate the formation of microbial biofilms. Due to the predilection toward a wet environment, strong adhesion, biofilm formation, and resistance to biocides, Pseudomonas aeruginosa, a major human opportunistic pathogen, is adapted to DCUW colonization. Other nonfermentative Gram-negative bacilli, such as members of the genus Achromobacter, are emerging pathogens found in water networks. We reported the 6.5-year dynamics of bacterial contamination of waterlines in a dental health care center with 61 dental care units (DCUs) connected to the same water supply system. The conditions allowed the selection and the emergence of clones of Achromobacter sp. and P. aeruginosa characterized by multilocus sequence typing, multiplex repetitive elements-based PCR, and restriction fragment length polymorphism in pulsed-field gel electrophoresis, biofilm formation, and antimicrobial susceptibility. One clone of P. aeruginosa and 2 clones of Achromobacter sp. colonized successively all of the DCUWs: the last colonization by P. aeruginosa ST309 led to the closing of the dental care center. Successive dominance of species and clones was linked to biocide treatments. Achromobacter strains were weak biofilm producers compared to P. aeruginosa ST309, but the coculture of P. aeruginosa and Achromobacter enhanced P. aeruginosa ST309 biofilm formation. Intraclonal genomic microevolution was observed in the isolates of P. aeruginosa ST309 collected chronologically and in Achromobacter sp. clone A. The contamination control was achieved by a complete reorganization of the dental health care center by removing the connecting tubes between DCUs.

Achromobacter sediminum sp. nov., isolated from deep subseafloor sediment of South Pacific Gyre.

A Gram-stain-negative, facultatively anaerobic, rod-shaped, motile bacterium with a subpolar or lateral flagellum, designated strain XH089(T), was isolated from deep-sea sediment sample collected from the South Pacific Gyre (41°51' S 153°06' W) during the Integrated Ocean Drilling Program (IODP) Expedition 329. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain XH089(T) belonged to the genus Achromobacter and showed the highest 16S rRNA gene sequence similarities with Achromobacter ruhlandii ATCC 15749(T) (96.95%), Achromobacter denitrificans DSM 30026(T) (96.70%) and Achromobacter marplatensis B2(T) (96.66%). The DNA G+C content of strain XH089(T) was 66.5 mol%. The major fatty acids were C16: 0 and C17: 0 cyclo. The major polar lipids were phosphatidylethanolamine, phosphatidylmonomethylethanolamine, diphosphatidylglycerol, three unknown phospholipids and four unknown polar lipids. On the basis of data from the polyphasic analysis, strain XH089(T) is considered to represent a novel species of the genus Achromobacter, for which the name Achromobacter sediminum sp. nov. is proposed. The type strain is XH089(T) ( = DSM 27279(T) = JCM 19223(T)).