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Microbiology Spectrum Feb 2023The genus includes opportunistic pathogens that can cause chronic infections in immunocompromised patients, especially in people with cystic fibrosis (CF). Treatment of...
The genus includes opportunistic pathogens that can cause chronic infections in immunocompromised patients, especially in people with cystic fibrosis (CF). Treatment of infections is complicated by antimicrobial resistance. In this study, a collection of clinical isolates, from CF and non-CF sources, was investigated for polymyxin B (PmB) resistance. Additionally, the effect of PmB challenge in a subset of isolates was examined and the presence of PmB-resistant subpopulations within the isolates was described. Further, chemical and mass spectrometry analyses of the lipid A of clinical isolates enabled the determination of the most common structures and showed that PmB challenge was associated with lipid A modifications that included the addition of glucosamine and palmitoylation and the concomitant loss of the free phosphate at the C-1 position. This study demonstrates that lipid A modifications associated with PmB resistance are prevalent in and that subresistant populations displaying the addition of positively charged residues and additional acyl chains to lipid A can be selected for and isolated from PmB-sensitive clinical isolates. species can cause chronic and potentially severe infections in immunocompromised patients, especially in those with cystic fibrosis. Bacteria cannot be eradicated due to 's intrinsic multidrug resistance. We report that intrinsic resistance to polymyxin B (PmB), a last-resort antimicrobial peptide used to treat infections by multiresistant bacteria, is prevalent in clinical isolates; many isolates also display increased resistance upon PmB challenge. Analysis of the lipopolysaccharide lipid A moiety of several species reveals a penta-acylated lipid A, which in the PmB-resistant isolates was modified by the incorporation of glucosamine residues, an additional acyl chain, loss of phosphates, and hydroxylation of acyl chains, all of which can enhance PmB resistance in other bacteria. We conclude that PmB resistance, particularly in isolates from chronic respiratory infections, is a common phenomenon, and that lipid A displays modifications that may confer increased resistance to polymyxins and potentially other antimicrobial peptides.
Topics: Humans; Polymyxins; Achromobacter; Polymyxin B; Lipid A; Lipopolysaccharides; Cystic Fibrosis; Anti-Bacterial Agents; Microbial Sensitivity Tests
PubMed: 36519943
DOI: 10.1128/spectrum.03729-22 -
Pathogens (Basel, Switzerland) Jan 2022is an opportunistic pathogen that mainly causes chronic lung infections in cystic fibrosis (CF) patients and is associated with increased mortality. Little is known...
is an opportunistic pathogen that mainly causes chronic lung infections in cystic fibrosis (CF) patients and is associated with increased mortality. Little is known about spp. in the lung transplant recipient (LTXr) population. We aimed at describing rates of spp. infection in LTXr prior to, in relation to, and after transplantation, as well as all-cause mortality proportion in infected and uninfected LTXr. We included 288 adult LTXr who underwent lung transplantation (LTX) between 1 January 2010 and 31 December 2019 in Denmark. Bronchoalveolar lavage was performed at regular intervals starting two weeks after transplantation. Positive cultures of spp. were identified in nationwide microbiology registries, and infections were categorized as persistent or transient, according to the proportion of positive cultures. A total of 11 of the 288 LTXr had transient ( = 7) or persistent ( = 4) spp. infection after LTX; CF was the underlying disease in 9 out of 11 LTXr. Three out of the four patients, with persistent infection after LTX, also had persistent infection before LTX. The cumulative incidence of the first episode of infection one year after LTX was 3.8% (95% CI: 1.6-6.0). The incidence rates of transient and persistent infection in the first year after LTX were 27 (12-53) and 15 (5-37) per 1000 person-years of follow-up, respectively. The all-cause mortality proportion one year after LTX was 27% in the spp. infected patients and 12% in the uninfected patients ( = 0.114). spp. mainly affected LTXr with CF as the underlying disease and was rare in non-CF LTXr. Larger studies are needed to assess long-term outcomes of spp. in LTXr.
PubMed: 35215124
DOI: 10.3390/pathogens11020181 -
Pediatric Pulmonology Mar 2022The prevalence of Achromobacter spp. in cystic fibrosis (CF) has increased while its significance remains controversial. Our aim was to investigate the impact of...
BACKGROUND
The prevalence of Achromobacter spp. in cystic fibrosis (CF) has increased while its significance remains controversial. Our aim was to investigate the impact of Achromobacter spp. isolation on clinical outcomes in children with CF.
METHODS
Children with Achromobacter spp. isolation were retrospectively included from the CF database of our center. Control groups of children with CF, who had never been infected by Achromobacter spp., were individually case-matched by age, sex, and Pseudomonas aeruginosa isolation status. Pulmonary function and exacerbation frequency were compared between groups during follow-up.
RESULTS
Thirty-seven children had at least one respiratory specimen positive for Achromobacter spp. Achromobacter spp. were chronically isolated from 15 (40.5%) and intermittently from 22 (59.5%) of these 37 children. Although the baseline forced expiratory volume in 1 s (FEV1) z-score was similar between the Achromobacter spp.-infected and -uninfected groups (-0.65 ± 2.22 vs. -0.15 ± 1.30, respectively; p = 0.318), children infected by Achromobacter spp. had a lower FEV1 z-score compared to the control group by the end of the first year (-1.37 ± 2.17 vs. -0.14 ± 1.65, respectively; p = 0.025). In addition, the FEV1 decline in 1 year was significantly greater in the group infected by Achromobacter spp. compared to the uninfected group (-1.18%/year vs. -9.07%/year, respectively; p = 0.043). Furthermore, the cumulative numbers of exacerbations observed in the Achromobacter spp.-infected group were higher compared to the control group by the end of the second year (4 [0-17] versus 3 [0-9], respectively; p = 0.001).
CONCLUSIONS
Achromobacter spp. isolation is associated with more accelerated decline in lung function parameters and frequent exacerbations in children with CF.
Topics: Achromobacter; Child; Cystic Fibrosis; Forced Expiratory Volume; Humans; Respiratory Function Tests; Retrospective Studies
PubMed: 34918495
DOI: 10.1002/ppul.25793 -
Journal of Environmental Science and... 2022Halogenated carbazoles are a new class of persistent organic pollutants with dioxin-like toxicity, and this study focused on the microbial degradation of...
Halogenated carbazoles are a new class of persistent organic pollutants with dioxin-like toxicity, and this study focused on the microbial degradation of 1,3,6,8-tetrabromocarbazole. In this study, a novel 1,3,6,8-tetrabromocarbazole (1,3,6,8-TBCZ) degrading strain TB-1 was isolated from contaminated soil and identified as sp. based on its 16S rRNA gene sequence analysis, morphological, physiological, and biochemical characteristics. The soil sample was collected from a pharmaceutical factory in Suzhou, China. The strain was able to effectively degrade 1 mg L 1,3,6,8-TBCZ in 7 d at pH 7.0 and 30 °C with 80% degradation rate. During the process, the intermediate metabolites were identified as Tribromocarbazole, dibromocarbazole and bromocarbazole via gas chromatography mass spectrometry (GC-MS). The results indicated that strain TB-1 may contribute to the bioremediation of polyhalogenated carbazoles (PHCs) in contaminated environment.
Topics: Achromobacter; Biodegradation, Environmental; Carbazoles; RNA, Ribosomal, 16S; Soil; Soil Microbiology; Soil Pollutants
PubMed: 35615782
DOI: 10.1080/10934529.2022.2079339 -
Microbial Genomics Jul 2020Several members of the Gram-negative environmental bacterial genus are associated with serious infections, with being the most common. Despite their pathogenic...
Several members of the Gram-negative environmental bacterial genus are associated with serious infections, with being the most common. Despite their pathogenic potential, little is understood about these intrinsically drug-resistant bacteria and their role in disease, leading to suboptimal diagnosis and management. Here, we performed comparative genomics for 158 spp. genomes to robustly identify species boundaries, reassign several incorrectly speciated taxa and identify genetic sequences specific for the genus and for . Next, we developed a Black Hole Quencher probe-based duplex real-time PCR assay, Ac-Ax, for the rapid and simultaneous detection of spp. and from both purified colonies and polymicrobial clinical specimens. Ac-Ax was tested on 119 isolates identified as spp. using phenotypic or genotypic methods. In comparison to these routine diagnostic methods, the duplex assay showed superior identification of spp. and , with five isolates failing to amplify with Ac-Ax confirmed to be different genera according to 16S rRNA gene sequencing. Ac-Ax quantified both spp. and down to ~110 genome equivalents and detected down to ~12 and ~1 genome equivalent(s), respectively. Extensive analysis, and laboratory testing of 34 non- isolates and 38 adult cystic fibrosis sputa, confirmed duplex assay specificity and sensitivity. We demonstrate that the Ac-Ax duplex assay provides a robust, sensitive and cost-effective method for the simultaneous detection of all spp. and and will facilitate the rapid and accurate diagnosis of this important group of pathogens.
Topics: Achromobacter; Achromobacter denitrificans; Cystic Fibrosis; Early Diagnosis; Genomics; Gram-Negative Bacterial Infections; Humans; Multilocus Sequence Typing; Phenotype; Phylogeny; RNA, Ribosomal, 16S; Real-Time Polymerase Chain Reaction; Sequence Analysis, DNA; Sputum
PubMed: 32667877
DOI: 10.1099/mgen.0.000406 -
Current Microbiology Jan 2021A novel strain KS-M25 was isolated from estuary water in South Korea. Strain KS-M25 was Gram-staining-negative, strictly aerobic, motile rods-shaped bacterium and showed...
A novel strain KS-M25 was isolated from estuary water in South Korea. Strain KS-M25 was Gram-staining-negative, strictly aerobic, motile rods-shaped bacterium and showed oxidase- and catalase-positive reactions. Growth of strain KS-M25 was observed at 10-25 °C (optimum, 20 °C), at pH 5.5-9.0 (optimum, pH 7.5), and with 0-6.0% (w/v) NaCl (optimum, 1%). Ubiquinone-8 was identified as the sole isoprenoid quinone and the major fatty acids were C cyclo-C and sum in feature 3 (comprising C ω7c and/or C ω6c). The G+C content values based on genome sequences was 62.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain KS-M25 formed a clear cluster within the genus Achromobacter. Strain KS-M25 was most closely related to Achromobacter anxifer LMG 26857, Achromobacter dolens LMG 26840, and Achromobacter xylosoxidans NBRC 15126 with 97.8%, 97.8%, and 97.7% 16S rRNA gene sequence similarities, respectively. Based on phenotypic, chemotaxonomic, and phylogenetic analysis, strain KS-M25 represents a novel species of the genes Achromobacter, for which the name Achromobacter aestuarii sp. nov. is proposed. The type strain is KS-M25 (= KACC 21219 = JCM 33329).
Topics: Achromobacter; Bacterial Typing Techniques; DNA, Bacterial; Estuaries; Fatty Acids; Phospholipids; Phylogeny; RNA, Ribosomal, 16S; Republic of Korea; Sequence Analysis, DNA
PubMed: 33033853
DOI: 10.1007/s00284-020-02231-9 -
Access Microbiology 2023is a Gram-negative, motile, obligate aerobic and non-fermentative bacterium. It is an emerging pathogen in the hospital environment as it is frequently found in various...
INTRODUCTION
is a Gram-negative, motile, obligate aerobic and non-fermentative bacterium. It is an emerging pathogen in the hospital environment as it is frequently found in various solutions.
HYPOTHESIS/GAP STATEMENT
Information about the incidence and risk factors of bacteremia from India is limited.
AIM
We conducted this study to identify the risk factors and underlying conditions predisposing to bacteremia by spp. and analyse the antibiotic resistance pattern of the isolates.
METHODOLOGY
We performed a retrospective observational study where automated blood cultures positive for spp. were assessed for clinical characteristics and antibiotic susceptibility patterns from January 2022 to December 2022 in the microbiology laboratory of a tertiary care centre in Northern India.
RESULTS
A total of 14 cases (14/2435, 0.57 %) of spp. were identified from bloodstream infections in one year. The mean age of the patients was 37.59±23.17 years with a male predominance (8/14, 57.1 %). All patients were managed on intravenous antibiotics and intravenous access as peripheral line catheters and only 5(5/14, 35.7 %) patients were managed on central line catheters. The isolates were found highly susceptible to ticarcillin-clavulanic acid (14/14, 100.0 %) followed by fluoroquinolones (12/14, 85.72 %) and trimethoprim-sulphamethoxazole (12/14, 85.72 %). Only 57.14 % (8/14, 57.14 %) of the patients were susceptible to piperacillin-tazobactam. The all-cause 40 day mortality was observed in 35.7 % (5/14, 35.7 %) with two deaths that were directly attributable to sepsis.
CONCLUSION
This study provides insight into the incidence of bacteremia at our centre and the necessary antibiotic therapy to combat it.
PubMed: 37841106
DOI: 10.1099/acmi.0.000588.v3 -
Journal of Cystic Fibrosis : Official... Mar 2023Achromobacter species are emerging pathogens isolated from respiratory samples of Patients with cystic fibrosis (pwCF) causing growing concerns in the CF community. The...
BACKGROUND
Achromobacter species are emerging pathogens isolated from respiratory samples of Patients with cystic fibrosis (pwCF) causing growing concerns in the CF community. The epidemiology and the clinical impact of Achromobacter in CF is unclear since data are restricted to small case control studies or selected populations.
AIM
To characterize the effect of Achromobacter respiratory infection on CF lung disease.
METHODS
European CF Society Patient Registry data was analysed for association between Achromobacter infection and demographic/clinical characteristics and outcomes of pwCF.
RESULTS
Of eligible 38,795 patients, Achromobacter infection was reported in 2,093 (prevalence (95% CI) of 5.40% (5.17 - 5.62). The prevalence varied significantly between the countries and increased with age peaking at the age 20-30. Achromobacter infection was more prevalent in pwCF carrying class minimal function mutations, having worse nutrition or lower pulmonary function, and more patients inhaled antibiotics against P. aeruginosa. Patient infected with Achromobacter had similar pulmonary function and BMI to patients infected with P. aeruginosa at all age groups. Being infected with both bacteria was associated with significantly lower pulmonary function and BMI at all age groups.
CONCLUSIONS
Achromobacter infection was associated with disease severity similar to infection with P. aeruginosa. Being infected with both bacteria is associated with even more severe disease. This suggests to study if eradication will improve the outcome of pwCF.
Topics: Humans; Young Adult; Adult; Cystic Fibrosis; Achromobacter; Gram-Negative Bacterial Infections; Lung; Respiratory Tract Infections; Pseudomonas aeruginosa
PubMed: 36418214
DOI: 10.1016/j.jcf.2022.11.001 -
Frontiers in Microbiology 2022genus (including , the most prevalent species in patients with cystic fibrosis) is poorly susceptible to most conventional antibiotics. Contribution of efflux by...
genus (including , the most prevalent species in patients with cystic fibrosis) is poorly susceptible to most conventional antibiotics. Contribution of efflux by AxyABM, AxyXY-OprZ, and AxyEF-OprN and of target mutations were studied in clinical isolates of and Forty-one isolates longitudinally collected from 21 patients with CF were studied by whole-genome sequencing (WGS)-typing, determination of minimum inhibitory concentrations (MICs) of β-lactams, aminoglycosides, colistin, azithromycin, ciprofloxacin, chloramphenicol, and doxycycline, and expression (quantitative RT-PCR) and function (measure of the uptake of a fluorescent substrate) of efflux pumps. WGS-based typing resulted in 10 clusters comprising 2 or 3 isolates and 20 singletons. The efflux activity was high in strains with elevated MICs for amikacin or azithromycin. This work sheds a new light on the impact of efflux and target mutations in resistance of to several drugs.
PubMed: 35418957
DOI: 10.3389/fmicb.2022.762307 -
Environmental Research Mar 2023In order to solve nitrogen pollution in environmental water, two heterotrophic nitrifying and aerobic denitrifying strains isolated from acid paddy soil were identified...
In order to solve nitrogen pollution in environmental water, two heterotrophic nitrifying and aerobic denitrifying strains isolated from acid paddy soil were identified as Achromobacter sp. strain HNDS-1 and Enterobacter sp. strain HNDS-6 respectively. Strain HNDS-1 and strain HNDS-6 exhibited amazing ability to nitrogen removal. When (NH)SO, KNO, NaNO were used as nitrogen resource respectively, the NH-N, NO-N, NO-N removal efficiencies of strain HNDS-1 were 93.31%, 89.47%, and 100% respectively, while those of strain HNDS-6 were 82.39%, 96.92%, and 100%. And both of them could remove mixed nitrogen effectively in low C/N (C/N = 5). Strain HNDS-1 could remove 76.86% NH-N and 75.13% NO-N. And strain HNDS-6 can remove 65.07% NH-N and 78.21% NO-N. A putative ammonia monooxygenase, nitrite reductase, nitrate reductase, assimilatory nitrate reductase, nitrate/nitrite transport protein and nitric oxide reductase of strain HNDS-1, while hydroxylamine reductase, nitrite reductase, nitrate reductase, assimilatory nitrate reductase, nitrate/nitrite transport protein, and nitric oxide reductase of strain HNDS-6 were identified by genomic analysis. DNA-SIP analysis showed that genes Nxr, narG, nirK, norB, nosZ were involved in nitrogen removal pathway, which indicates that the denitrification pathway of strain HNDS-1 and strain HNDS-6 was NO→NO→NO→NO→N during NH-N removal process. And the nitrification pathway of strain HNDS-1 and strain HNDS-6 was NO→NO, but the nitrification pathway of NH→ NO needs further studies.
Topics: Achromobacter; Aerobiosis; Denitrification; Enterobacter; Nitrates; Nitrification; Nitrite Reductases; Nitrites; Nitrogen; Nitrogen Dioxide
PubMed: 36621544
DOI: 10.1016/j.envres.2023.115240