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1.
J Hazard Mater ; 443(Pt B): 130378, 2023 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-36444069

RESUMO

Here, a novel phosphate-solubilizing bacterium (PSB), Klebsiella aerogenes Wn was applied to develop an environmental-friendly method to simultaneously stabilize Pb and Cd. The maximum dissolved phosphate was up to 701.36 mg/L by the strain Wn. The high performance liquid chromatography (HPLC) and Pearson correlation analyses showed that the acetic acid produced by the strain Wn was significantly positively associated with the released phosphate. Moreover, 100% of 500 mg/L of Pb and 100 mg/L of Cd were simultaneously stabilized in the classical NBRIP medium and the major products were Pb5(PO4)3Cl, Ca7.7Cd0.8(PO4)8(H2O)2.4 and CdS, respectively. In addition, the bacterial genome and transcriptome analyses showed that the pentose phosphate pathway (PPP), pyruvate metabolism pathway, thiamine metabolic pathway, sulfate reduction and ammonium bio-transformation were coupled to promote releasing insoluble phosphate and stabilizing Pb and Cd. In the metabolism networks, the critical genes of gcd, aceE, thiE, thiS and cysH, etc. were significantly up-regulated. Our results are beneficial to deeper understand the molecular mechanisms of releasing insoluble inorganic phosphate by PSBs and develop a technology prototype to simultaneously stabilize Pb and Cd using the PSBs.


Assuntos
Compostos de Amônio , Enterobacter aerogenes , Sulfatos , Fosfatos , Cádmio , Chumbo , Compostos Orgânicos
2.
Artigo em Inglês | MEDLINE | ID: mdl-36430078

RESUMO

Gentamicin is an aminoglycoside antibiotic that is mostly used for the pediatric population. While the pediatric population is classified into neonates, infants, children, and adolescents based on developmental or maturational changes, infants are often overlooked in research. Three infant cases receiving gentamicin are presented to illustrate the pharmacokinetics and optimum dosage of gentamicin. Three infant patients received gentamicin (5.6-7.5 mg/kg/day) for urinary tract infections (UTIs) or bacteremia caused by Enterobacter aerogenes. The trough (Cmin) and peak (Cpeak) concentrations of gentamicin were 0.2-1.8 and 8.9 mg/L, respectively. The Cmin of a patient receiving gentamicin at 9.0 mg/kg/day was 3.3 mg/L, and the patient showed a decrease in urinary volume. The other two patients fully recovered from the infection and did not experience any adverse events. Additionally, we reviewed three studies regarding infant patients receiving gentamicin. The studies used gentamicin therapy for Gram-negative pathogen infections and UTIs caused by Escherichia coli and Enterococcus faecalis. The Cmin and Cpeak of patients receiving gentamicin at 2.2-7.5 mg/kg/day were 0.58-2.15 mg/kg and 4.67-8.88 mg/L, respectively. All patients were cured without any adverse events. Gentamicin dosages below 7.5 mg/kg/day may be effective and safe for use in infant patients. However, the optimal dosing regimen of gentamicin in infant patients is controversial, and limited data are available.


Assuntos
Bacteriemia , Enterobacter aerogenes , Infecções por Escherichia coli , Criança , Adolescente , Lactente , Recém-Nascido , Humanos , Gentamicinas/uso terapêutico , Antibacterianos/uso terapêutico , Bacteriemia/tratamento farmacológico , Escherichia coli
3.
J Biotechnol ; 358: 67-75, 2022 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-36087783

RESUMO

As a valuable platform chemical, 2,3-Butanediol (2,3-BDO) has a variety of industrial applications, and its microbial production is particularly attractive as an alternative to petroleum-based production. In this study, the regulation of intracellular carbon flux and NADH/NAD+ was used to increase the 2,3-BDO production of Enterobacter aerogenes. The genes encoding lactate dehydrogenase (ldh) and pyruvate formate lyase (pfl) were disrupted using the λ-Red recombination method and CRISPR-Cas9 to reduce the production of several byproducts and the consumption of NADH. Knockout of ldh or pfl increased intracellular NADH/NAD+ by 111 % and 113 %, respectively. Moreover, two important genes in the 2,3-BDO biosynthesis pathway, acetolactate synthase (budB) and acetoin reductase (budC), were overexpressed in E. aerogenes to further amply the metabolic flux toward 2,3-BDO production. And the overexpression of budB or budC increased intracellular NADH/NAD+ by 46 % and 57 %, respectively. In shake-flask cultivation with sucrose as carbon source, the 2,3-BDO titer of the IAM1183-LPBC was 3.55 times that of the wild type. In the 5-L fermenter, the maximal 2,3-BDO production produced by the IAM1183-LPBC was 2.88 times that of the original strain. This work offers new ideas for promoting the biosynthesis of 2,3-BDO for industrial applications.


Assuntos
Acetolactato Sintase , Enterobacter aerogenes , Liases , Petróleo , Acetolactato Sintase/metabolismo , Butileno Glicóis/metabolismo , Carbono/metabolismo , Ciclo do Carbono , Enterobacter aerogenes/genética , Enterobacter aerogenes/metabolismo , Fermentação , Formiatos , L-Lactato Desidrogenase/genética , Engenharia Metabólica/métodos , NAD/metabolismo , Piruvatos , Sacarose
4.
Sci Rep ; 12(1): 14402, 2022 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-36002561

RESUMO

A rapid rise in antibiotic resistance by bacterial pathogens is due to these pathogens adaptation to the changing environmental conditions. Antibiotic resistance infections can be reduced by a number of ways such as development of safe and effective vaccine. Klebsiella aerogene is a gram-negative, rod-shaped bacterium resistant to a variety of antibiotics and no commercial vaccine is available against the pathogen. Identifying antigens that can be easily evaluated experimentally would be crucial to successfully vaccine development. Reverse vaccinology (RV) was used to identify vaccine candidates based on complete pathogen proteomic information. The fully sequenced proteomes include 44,115 total proteins of which 43,316 are redundant and 799 are non-redundant. Subcellular localization showed that only 1 protein in extracellular matrix, 7 were found in outer-membrane proteins, and 27 in the periplasm space. A total of 3 proteins were found virulent. Next in the B-cell-derived T-cell epitopes mapping phase, the 3 proteins (Fe2+- enterobactin, ABC transporter substrate-binding protein, and fimbriae biogenesis outer membrane usher protein) were tested positive for antigenicity, toxicity, and solubility. GPGPG linkers were used to prepare a vaccine construct composed of 7 epitopes and an adjuvant of toxin B subunit (CTBS). Molecular docking of vaccine construct with major histocompatibility-I (MHC-I), major histocompatibility-II (MHC-II), and Toll-like receptor 4 (TLR4) revealed vaccine robust interactions and stable binding pose to the receptors. By using molecular dynamics simulations, the vaccine-receptors complexes unveiled stable dynamics and uniform root mean square deviation (rmsd). Further, binding energies of complex were computed that again depicted strong intermolecular bindings and formation of stable conformation.


Assuntos
Enterobacter aerogenes , Vacinas Bacterianas , Biologia Computacional , Epitopos , Epitopos de Linfócito T , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Proteômica , Vacinas de Subunidades
5.
BMC Infect Dis ; 22(1): 616, 2022 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-35840919

RESUMO

BACKGROUND: The early clinical diagnosis of spinal infections in elderly patients with recessive or atypical symptoms is difficult. Klebsiella aerogenes is a common opportunistic bacterium that can infect the respiratory tract, urinary tract, and even the central nervous system. However, whether it can infect the lumbar spine has not been previously described. CASE PRESENTATION: In this paper, we report the case of a 69-year-old female patient with osteoporosis who was initially diagnosed with hemolytic anemia. Later, she was diagnosed with K. aerogenes infection of the lumbar spine based on imaging combined with blood culture and metagenome next-generation sequencing (mNGS) detection. After precise medication, the lumbar degeneration was improved. CONCLUSIONS: Bacterial infection should therefore be considered in cases of lumbar degenerative disease in middle-aged and elderly patients.


Assuntos
Enterobacter aerogenes , Infecções por Klebsiella , Idoso , Feminino , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Humanos , Infecções por Klebsiella/diagnóstico , Vértebras Lombares , Metagenoma , Pessoa de Meia-Idade
6.
J Food Prot ; 85(10): 1452-1457, 2022 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-35880908

RESUMO

ABSTRACT: Fresh cucumbers have been linked to multistate outbreaks of salmonellosis in the United States. Cutting, slicing, shredding, or peeling can transfer pathogens from the surface of fresh produce to the edible flesh portion through tools or hands. Different nonpathogenic surrogates have been used in various intervention studies to predict Salmonella behavior. Little is known about the degree to which pathogens or their surrogates can transfer from the surface of fresh produce to edible flesh during peeling. This study quantifies the transfer of Salmonella Newport from the surface of cucumber to the edible flesh portion or peeler during peeling and evaluates Enterobacter aerogenes B199A, as well as native mesophilic microbiota, as surrogates for Salmonella transfer. Cucumbers were dip inoculated with Salmonella Newport or E. aerogenes at 7 log CFU per cucumber. Half of each inoculated cucumber was hand peeled by using a sterilized peeler, resulting in four separate samples (unpeeled half, edible flesh half, removed peel, and used peeler) to quantify bacterial transfer. Most (>95%) of inoculated E. aerogenes, Salmonella, or native mesophilic microbiota generally remained associated with the peel during peeling. E. aerogenes transfer to cucumber flesh ranged from 0.02 to 12.9%, while transfer to the peeler ranged from 0.01 to 6.6%. Salmonella to cucumber flesh ranged from 0 to 0.6%, while transfer to the peeler ranged from 0 to 2.2%. Native microflora transfer to cucumber flesh ranged from 0.02 to 3.7%, while transfer to the peeler ranged from 0.04 to 3.7%. The log percent transfer of E. aerogenes at 24 h, as well as several shorter times, was not significantly different (P > 0.05) from that of Salmonella transferred to the edible flesh portion or peeler during peeling. E. aerogenes B199A may be a useful surrogate for Salmonella in cross-contamination studies and may help guide future risk management efforts to reduce pathogen risk associated with fresh cucumbers.


Assuntos
Cucumis sativus , Enterobacter aerogenes , Contagem de Colônia Microbiana , Cucumis sativus/microbiologia , Microbiologia de Alimentos , Salmonella
8.
Pediatr Infect Dis J ; 41(7): 593-599, 2022 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-35421055

RESUMO

BACKGROUND: Yersiniabactin, a siderophore with a high affinity to iron, has been described as a potential virulence factor in Enterobacteriaceae. Klebsiella aerogenes is a Gram-negative rod known to cause invasive infection in very low birth weight infants but is an unusual pathogen to cause outbreaks in neonatal intensive care units (NICU). METHODS: We performed a retrospective analysis of all patients colonized with K. aerogenes in our NICU from September to December 2018. Each infant with an occurrence of K. aerogenes in any microbiological culture was defined as a case. Clinical data were taken from medical charts. K. aerogenes isolates were genotyped using whole-genome sequencing combined with core genome multilocus sequencing type analysis. Yersiniabactin production was evaluated by luciferase assay. RESULTS: In total 16 patients were colonized with K. aerogenes over the 3-month period and 13 patients remained asymptomatic or developed late-onset neonatal sepsis from another pathogen. Three patients developed necrotizing enterocolitis, 2 complicated by sepsis and 1 of them died. All symptomatic patients were premature infants with low birth weight. Genetic sequencing confirmed an outbreak with the same strain, all samples expressed the high-pathogenicity island, necessary for the production of yersiniabactin. Six exemplary cases were proven to produce yersiniabactin in vitro. CONCLUSION: This is the first report of an outbreak of a yersiniabactin-producing K. aerogenes strain causing invasive infection in preterm infants. We hypothesize that, due to improved iron uptake, this strain was associated with higher virulence than non-yersiniabactin-producing strains. Extended search for virulence factors and genetic sequencing could be pivotal in the management of NICU outbreaks in the future.


Assuntos
Infecção Hospitalar , Enterobacter aerogenes , Infecções por Klebsiella , Áustria , Infecção Hospitalar/microbiologia , Surtos de Doenças , Humanos , Lactente , Recém-Nascido , Recém-Nascido Prematuro , Unidades de Terapia Intensiva Neonatal , Ferro , Infecções por Klebsiella/epidemiologia , Infecções por Klebsiella/microbiologia , Klebsiella pneumoniae/genética , Fenóis , Estudos Retrospectivos , Tiazóis , beta-Lactamases
9.
Acta Trop ; 232: 106485, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35487296

RESUMO

The prevalence of multidrug-resistant Enterobacter aerogenes strains in UTIs is increasing. Therefore, the purpose of this study was to examine the mechanisms of resistance in Enterobacter aerogenes strains isolated from the urinary tract of infected patients. To achieve this goal, 786 urine samples from Shahrekord, Iran, were collected from June 2019 to February 2020. After isolating and identifying E. aerogenes samples, antibiotic susceptibility testing was done on the strains using Kirby-Bauer's disk diffusion method. The biofilm formation assays were performed to study the link between antibiotic resistance and biofilm formation and virulence genes. As a result, amongst the 786 urine samples, 50 strains were identified as E. aerogenes. The lowest rate of resistance was observed with imipenem (30%). This study also reports that all the strains of E. aerogenes are biofilm producers, with 50% of isolates producing a large amount, 30% a moderate amount, and 20% a small amount of biofilm. 42% were identified in the phenotypic study of ESBLs. In the PCR test, (64%) produced broad-spectrum beta-lactamases. Prevalence of qnrC, qnrB, qnrA, tetA, tet B, acc(3)IIa, acc(2)IIa, ant(2)Ia and Sul1 in strong producing isolates reported 100%, 80.95%,% 58.14, 87.5%, 81.58%, 86.67%, 82.14, 81.48% and 90% respectively. In the statistical analysis based on the chi-square test, a statistically significant relationship was reported between qnrA, qnrB, tetA, tetB, Sul1, ant(2)Ia, ant(3)I, aac(3)II, and biofilm formation. Resistance to cephalothin, ceftriaxone, cefotaxime and ceftazidime were reported 40%, 34%, 30% and 30%, respectively. Out of 50 Enterobacter aerogenes, 32 isolates (64%) were identified in the phenotypic study of ESBLS, prevalence of blaCTX-M, blaTEM and blaSHV reported 30%, 20% and 14% respectively. There is a significant relationship between resistance to ceftriaxone and blaCTX-M. Prevalence of csgA, ybtS, markD, rmpA, csgD and fimH in strong biofilm formation isolates reported 84%, 83.33%, 80%, 80%, 80% and 66% respectively. The chi-square test showed a statistically significant relationship between biofilm production and resistance genes fimH, csgA, csgD, ybtS, and mrkD. The findings of this study indicate that the ability to produce biofilms is associated with the increase of antibiotic resistance and virulence genes. These agents enable bacteria to produce biofilms that ultimately lead to colonization and bacterial survival in the body.


Assuntos
Enterobacter aerogenes , Infecções Urinárias , Antibacterianos/farmacologia , Ceftriaxona , Enterobacter aerogenes/genética , Humanos , Irã (Geográfico)/epidemiologia , Testes de Sensibilidade Microbiana , Infecções Urinárias/epidemiologia , Infecções Urinárias/microbiologia
10.
Genomics ; 114(2): 110321, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35218872

RESUMO

Klebsiella (nee Enterobacter) aerogenes is the first human gut commensal bacterium with a documented sensitivity to the pineal/gastrointestinal hormone melatonin. Exogenous melatonin specifically increases the size of macrocolonies on semisolid agar and synchronizes the circadian clock of K. aerogenes in a concentration dependent manner. However, the mechanisms driving these phenomena are unknown. In this study, we applied RNA sequencing to identify melatonin sensitive transcripts during culture maturation. This work demonstrates that the majority of melatonin sensitive genes are growth stage specific. Melatonin exposure induced differential gene expression of 81 transcripts during exponential growth and 30 during early stationary phase. This indole molecule affects genes related to biofilm formation, fimbria biogenesis, transcriptional regulators, carbohydrate transport and metabolism, phosphotransferase systems (PTS), stress response, metal ion binding and transport. Differential expression of biofilm and fimbria-related genes may be responsible for the observed differences in macrocolony area. These data suggest that melatonin enhances Klebsiella aerogenes host colonization.


Assuntos
Relógios Circadianos , Enterobacter aerogenes , Melatonina , Enterobacter aerogenes/genética , Enterobacter aerogenes/metabolismo , Humanos , Klebsiella/genética , Melatonina/metabolismo , Melatonina/farmacologia
11.
Int J Food Microbiol ; 362: 109459, 2022 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-34861562

RESUMO

Indonesian salted-boiled fish (pindang) is a popular traditional food in Indonesia, which is made from Scombroid fish such as tuna and mackerel. As with other traditionally prepared fish products, pindang has important economic and social values, especially for those living in the coastal areas of Indonesia. However, pindang is a major cause of histamine fish poisoning (HFP) for consumers. Klebsiella aerogenes T124, a relatively high histamine-producing isolate from pindang, was used to describe lag time (λ), growth rate (µmax), maximum population density (Nmax), and histamine production in histidine broth and artificially contaminated Grey mackerel. Broth was adjusted to 1.5, 6, 10 and 20% w/v NaCl; mackerel was treated with 6% w/w NaCl, a level common to Indonesian industry practice, or not treated with additional NaCl. Samples were incubated at 10, 15, 20 and 30 °C. In broth, µmax and Nmax were significantly affected by temperature and NaCl, respectively, with λ influenced by both parameters. In control fish, µmax was significantly affected by temperature and NaCl, except at 10 and 15 °C; for 6% NaCl treatment, growth was only observed at 20 and 30 °C. Under similar incubation conditions for broth and fish, histamine formation was markedly affected by NaCl concentration. In broth, -5.1 to -6.6 log µg of histamine was produced per CFU, versus -4.6 to -6.6 log µg per CFU in fish. This study demonstrated that mackerel treated with 6% NaCl and stored at 10-15 °C prevents growth of K. aerogenes strain TI24 and formation of toxic levels of histamine.


Assuntos
Enterobacter aerogenes , Histamina , Animais , Produtos Pesqueiros/análise , Indonésia , Atum
12.
J Craniofac Surg ; 33(3): e281-e283, 2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-34456285

RESUMO

ABSTRACT: Klebsiella aerogenes is a nosocomial and pathogenic bacterium that causes opportunistic infections including most types of infections. After rhinoplasty, the inserted costochondral graft could be a good material for bacterial growth due to less vascularization and difficult-to-reach antibiotics. The unusual bacterial infection should be considered for preventing poor aesthetic results including graft or implant loss when the surgical site infection is uncontrolled despite proper treatment and administration in aesthetic rhinoplasty surgery. The use of appropriate antibiotics for drug sensitivity may be necessary with bacterial culture tests. In this case, an unusual K. aerogenes infection on the costochondral graft of the nose and related treatment course was reported.


Assuntos
Implantes Dentários , Enterobacter aerogenes , Rinoplastia , Antibacterianos/uso terapêutico , Estética Dentária , Humanos , Nariz/cirurgia , Rinoplastia/métodos
13.
Environ Res ; 205: 112189, 2022 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-34627801

RESUMO

Effluents of textile industries caused serious environmental problem throughout the world. In this study, a total of 23 bacterial strains from five bacterial species were isolated from the dye effluent. Of these strains, a unique and novel Enterobacter aerogenes ES014 was utilized for dye decolourization and toxicity analysis. The selected strain could effectively decolourize three selected azo dyes. It showed the capability for decolourizing acid orange (82.3 ± 3.6%), methyl orange (78.2 ± 3.3%), and congo red (81.5 ± 3.2%). The selected bacterial strain significantly decolourized 100 mg/L acid orange at 35 °C, pH 7.5 with 6% sodium chloride concentration. Most of the tested nitrogen and carbon sources effectively enhanced decolourization process. It showed the ability to decolourize acid orange in the culture medium containing 1.5% glucose (100 ± 2.8%) and 0.8% beef extract (100 ± 3.1%). A laboratory-scale batch bioreactor was used to decolourize azo dye at optimized culture conditions. The decolourizing ability improved with 100 mL/h hydraulic retention time. The treated wastewater quality was improved due to sharp depletion of Total Dissolved Solids (TDS), pH, Chemical Oxygen Demand (COD), alkalinity and sulphate concentration. The selected bacteria has the potential to produce dye degrading laccase. Laccase was detected during fermentation process in batch bioreactor as a key enzyme for decolourization produced by E. aerogenes ES014. Phytotoxicity and acute toxicity analysis were performed using Arachis hypogaea (pea nut) seed and first instar larvae of Artemia parthenogenetica (brine shrimp). The seed germination rate of treated wastewater was improved (94.3 ± 1.8%) and enhanced survival rate (91.7 ± 2.9%) in the first instar Artemia larvae treated with wastewater after 24 h. Overall, E. aerogenes ES014, might be a promising bacterial strain for the treatment of textile effluents with high azo dye concentrations.


Assuntos
Enterobacter aerogenes , Águas Residuárias , Compostos Azo/toxicidade , Bactérias , Biodegradação Ambiental , Reatores Biológicos , Corantes/toxicidade , Águas Residuárias/microbiologia
14.
Chemosphere ; 293: 133453, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34971630

RESUMO

Resistant bacteria are potential natural materials for the bioremediation of soil metalloid pollution. A strain isolated from farmland soil chronically exposed to Sb was identified as K. aerogenes X with high antimonite [Sb(III)] tolerance and oxidation ability. The resistance mechanism of K. aerogenes X and its extracellular polymeric substances (EPS), antioxidant enzymes, and oxidation characteristics in Sb(III) stress were investigated in this study by stress incubation experiments and FTIR. The biotoxicity of Sb was limited by the binding of the organic compounds in EPS, and the anionic functional groups (e.g., amino, carboxyl and hydroxyl groups, etc.) present in the cell envelope were the components primarily responsible for the metalloid-binding capability of K. aerogenes X. The K. aerogenes X can oxidize Sb(III), and its metabolites induce changes in reactive oxygen species (ROS), catalase (CAT), total superoxide dismutase (SOD) and glutathione s-transferase (GSH-S) activity, indicating that the resistance mechanisms of K. aerogenes X are mediated by oxidative stress, EPS restriction and cell damage. Oxidation of Sb(III) is driven by interactions in intracellular oxidation, cell electron transport, extracellular metabolism including proteins and low molecular weight components (LMWs). LMWs (molecular weight <3 kDa) are the main driving factor of Sb(III) oxidation. In addition, Sb resistance genes arsA, arsB, arsC, arsD and acr3 and potential oxidation gene arsH were identified in K. aerogenes X. Owing to its natural origin, high tolerance and oxidation ability, K. aerogenes X could serve as a potential bioremediation material for the mitigation of Sb(III) in contaminated areas.


Assuntos
Enterobacter aerogenes , Biodegradação Ambiental , Oxirredução , Solo , Microbiologia do Solo
15.
Food Funct ; 12(20): 9932-9946, 2021 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-34492674

RESUMO

Atherosclerosis is the leading cause of cardiovascular diseases worldwide. Trimethylamine N-oxide (TMAO), a metabolite of intestinal flora from dietary quaternary amines, has been shown to be closely related to the development of atherosclerosis. Previous studies have shown that Enterobacter aerogenes ZDY01 significantly reduces the serum levels of TMAO and cecal trimethylamine (TMA) in Balb/c mice; however, its role in the inhibition of choline-induced atherosclerosis in ApoE-/- mice remains unclear. Here, we demonstrated that E. aerogenes ZDY01 inhibited choline-induced atherosclerosis in ApoE-/- mice fed with 1.3% choline by reducing cecal TMA and modulating CDCA-FXR/FGF15 axis. We observed that E. aerogenes ZDY01 decreased the cecal TMA and serum TMAO levels by utilizing cecal TMA as a nutrient, not by changing the expression of hepatic FMO3 and the composition of gut microbiota. Furthermore, E. aerogenes ZDY01 enhanced the expression of bile acid transporters and reduced the cecal CDCA levels, thereby attenuating the FXR/FGF15 pathway, upregulating the expression of Cyp7a1, promoting reverse cholesterol transport. Taken together, E. aerogenes ZDY01 attenuated choline-induced atherosclerosis in ApoE-/- mice by decreasing cecal TMA and promoting reverse cholesterol transport, implying that E. aerogenes ZDY01 treatment might have therapeutic potential in atherosclerosis.


Assuntos
Aterosclerose/tratamento farmacológico , Proteínas de Ciclo Celular/metabolismo , Enterobacter aerogenes , Fatores de Crescimento de Fibroblastos/metabolismo , Probióticos/farmacologia , Animais , Aterosclerose/metabolismo , Aterosclerose/microbiologia , Ceco/metabolismo , Colesterol 7-alfa-Hidroxilase/metabolismo , Colina/efeitos adversos , Dieta/métodos , Feminino , Microbioma Gastrointestinal/efeitos dos fármacos , Metilaminas/análise , Metilaminas/sangue , Camundongos , Camundongos Knockout para ApoE , Proteínas de Ligação a RNA/metabolismo
16.
Pol J Microbiol ; 70(3): 409-412, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34584536

RESUMO

Bronchoscopes have been linked to outbreaks of nosocomial infections. The phenotypic and genomic profiles of bronchoscope-associated Klebsiella aerogenes isolates are largely unknown. In this work, a total of 358 isolates and 13 isolates were recovered from samples after clinical procedures and samples after decontamination procedures, respectively, over the five months. Antimicrobial susceptibility testing found seven K. aerogenes isolates exhibiting a low-level resistance to antimicrobial agents. Among seven K. aerogenes isolates, we found five sequence types (STs) clustered into three main clades. Collectively, this study described for the first time the phenotypic and genomic characteristics of bronchoscope-associated K. aerogenes.


Assuntos
Broncoscópios , Enterobacter aerogenes , Genoma Bacteriano , Antibacterianos/farmacologia , Broncoscópios/microbiologia , Farmacorresistência Bacteriana , Enterobacter aerogenes/efeitos dos fármacos , Enterobacter aerogenes/genética , Enterobacter aerogenes/isolamento & purificação , Genômica
17.
Int J Antimicrob Agents ; 58(5): 106439, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34547421

RESUMO

We investigated the prevalence, resistance mechanisms and activity of ceftazidime/avibactam, meropenem/vaborbactam, imipenem/relebactam and comparator agents against carbapenem-resistant Enterobacterales (CRE) that did not carry carbapenemase genes. Among 304 CRE isolates collected in US hospitals during 2016-2018 (1.1% of the overall Enterobacterales), 45 (14.8%) isolates did not carry carbapenemases. These isolates were mainly Klebsiella aerogenes (n = 11), Enterobacter cloacae (n = 11) and Klebsiella pneumoniae (n = 10). Isolates harboured one to six ß-lactam resistance mechanisms (median, three mechanisms). Acquired ß-lactamase genes were detected in 21 isolates; blaCTX-M-15 was the most common acquired ß-lactamase gene found (14 isolates). All 11 K. aerogenes and 6 E. cloacae isolates overexpressed AmpC. Only one isolate belonging to these species carried acquired ß-lactamase genes. Disruptions or reduced expression of both outer membrane proteins (ompC/ompK36 and ompF/ompK35) were detected among 20 isolates. AcrAB-TolC was modestly expressed or overexpressed among 19 isolates from six species. One E. coli isolate produced a CTX-M-15 variant that displayed an increased meropenem minimum inhibitory concentration (MIC) when expressed in a clean background. Most ß-lactam agents had limited activity against CRE isolates that did not carry carbapenemases. Ceftazidime/avibactam inhibited all isolates, while imipenem/relebactam and meropenem/vaborbactam inhibited 93.0% (88.9% if Proteus mirabilis is included) and 93.3% of tested isolates at current breakpoints. The resistance mechanisms among CRE isolates that did not produce carbapenemases are complex; ß-lactam/ß-lactamase inhibitor combinations might have different activity against these isolates depending on their resistance mechanisms and the bacterial species.


Assuntos
Antibacterianos/farmacologia , Compostos Azabicíclicos/farmacologia , Ácidos Borônicos/farmacologia , Enterobacteriáceas Resistentes a Carbapenêmicos/efeitos dos fármacos , Ceftazidima/farmacologia , Compostos Heterocíclicos com 1 Anel/farmacologia , Imipenem/farmacologia , Meropeném/farmacologia , Inibidores de beta-Lactamases/farmacologia , Proteínas de Bactérias/metabolismo , Enterobacteriáceas Resistentes a Carbapenêmicos/genética , Enterobacteriáceas Resistentes a Carbapenêmicos/isolamento & purificação , Combinação de Medicamentos , Farmacorresistência Bacteriana Múltipla/genética , Enterobacter aerogenes/efeitos dos fármacos , Enterobacter aerogenes/isolamento & purificação , Enterobacter cloacae/efeitos dos fármacos , Enterobacter cloacae/isolamento & purificação , Escherichia coli/efeitos dos fármacos , Escherichia coli/isolamento & purificação , Humanos , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/isolamento & purificação , Testes de Sensibilidade Microbiana , Estados Unidos , beta-Lactamases/genética , beta-Lactamases/metabolismo
18.
mSphere ; 6(4): e0059221, 2021 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-34346701

RESUMO

Tigecycline is a last-resort antimicrobial against carbapenemase-producing Enterobacterales (CPE). However, mobile tigecycline resistance genes, tet(X) and tmexCD-toprJ, have emerged in China and have spread possibly worldwide. Tet(X) family proteins function as tigecycline-inactivating enzymes, and TMexCD-TOprJ complexes function as efflux pumps for tigecycline. Here, to the best of our knowledge we report a CPE isolate harboring both emerging tigecycline resistance factors for the first time. A carbapenem- and tigecycline-resistant Klebsiella aerogenes strain, NUITM-VK5, was isolated from an urban drainage in Vietnam in 2021, and a plasmid, pNUITM-VK5_mdr, cocarrying tet(X) and tmexCD3-toprJ3 along with the carbapenemase gene blaNDM-4 was identified in NUITM-VK5. pNUITM-VK5_mdr was transferred to Escherichia coli by conjugation and simultaneously conferred high-level resistance against multiple antimicrobials, including carbapenems and tigecycline. An efflux pump inhibitor reduced TMexCD3-TOprJ3-mediated tigecycline resistance, suggesting that both tigecycline resistance factors independently and additively contribute to the high-level resistance. The plasmid had the IncX3 and IncC replicons and was estimated to be a hybrid of plasmids with different backbones. Unlike IncX3 plasmids, IncC plasmids are stably maintained in an extremely broad range of bacterial hosts in humans, animals, and the environment. Thus, the future global spread of multidrug resistance plasmids such as pNUITM-VK5_mdr poses a public health crisis. IMPORTANCE Tigecycline is important as a last-resort antimicrobial and effective against antimicrobial-resistant bacteria, such as carbapenem-producing Enterobacterales (CPE), whose infections are difficult to treat with antimicrobials. Since 2019, mobile tigecycline resistance genes, tet(X) and tmexCD-toprJ, and their variants have been reported mainly from China, and it has become important to understand their epidemiological situation and detailed genetic mechanisms. In this study, we identified a bacterial isolate coharboring tet(X) and tmexCD-toprJ on the same plasmid. A Klebsiella aerogenes isolate in Vietnam carried both these tigecycline resistance genes on a transferable plasmid leading to high-level resistance to multiple clinically important antimicrobials, including carbapenem and tigecycline, and could actually transfer the plasmid to other bacteria. The spread of such a multidrug resistance plasmid among bacterial pathogens should be of great concern because there are few antimicrobials to combat bacteria that have acquired the plasmid.


Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Carbapenêmicos/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Enterobacter aerogenes/efeitos dos fármacos , Enterobacter aerogenes/genética , Plasmídeos/genética , Tigeciclina/farmacologia , beta-Lactamases/genética , China , Enterobacter aerogenes/enzimologia , Infecções por Escherichia coli/microbiologia , Humanos , Infecções por Klebsiella/microbiologia , Testes de Sensibilidade Microbiana
19.
World J Microbiol Biotechnol ; 37(6): 106, 2021 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-34037848

RESUMO

A novel esterase (EstKa) from marine Klebsiella aerogenes was characterized with hydrolytic activity against p-nitrophenyl caprylate (pNPC, C8) under optimum conditions (50 °C and pH 8.5). After two rounds of mutagenesis, two highly potential mutants (I6E9 and L7B11) were obtained with prominent activity, substrate affinity and thermostability. I6E9 (L90Q/P96T) and L7B11 (A37S/Q100L/S133G/R138C/Q156R) were 1.56- and 1.65-fold higher than EstKa in relative catalytic efficiency. The influence of each amino acid on enzyme activity was explored by site-directed mutation. The mutants Pro96Thr and Gln156Arg showed 1.29- and 1.48-fold increase in catalytic efficiency (Kcat/Km) and 54.4 and 36.2% decrease in substrate affinity (Km), respectively. The compound mutant Pro96Thr/Gln156Arg exhibited 68.9% decrease in Km and 1.41-fold increase in Kcat/Km relative to EstKa. Homology model structure analysis revealed that the replacement of Gln by hydrophilic Arg on the esterase surface improved the microenvironment stability and the activity. The replacement of Pro by Thr enabled the esterase enzyme to retain 90% relative activity after 3 h incubation at 45 °C. Structural analysis confirmed that the formation of a hydrogen bond leads to a notable increase of catalytic efficiency under high temperature conditions.


Assuntos
Enterobacter aerogenes/enzimologia , Esterases/genética , Esterases/metabolismo , Mutagênese Sítio-Dirigida/métodos , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Caprilatos/metabolismo , Catálise , Enterobacter aerogenes/genética , Estabilidade Enzimática , Esterases/química , Hidrólise , Homologia Estrutural de Proteína , Especificidade por Substrato
20.
J Glob Antimicrob Resist ; 25: 351-358, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33964492

RESUMO

OBJECTIVES: The genus Enterobacter is a common cause of nosocomial infections. Historically, the most frequent Enterobacter species were those of Enterobacter cloacae complex and Enterobacter aerogenes. In 2019, E. aerogenes was re-classified as Klebsiella aerogenes owing to its higher genotypic similarity with the genus Klebsiella. Our objective was to characterise and compare the clinical profiles of bacteraemia caused by E. cloacae and K. aerogenes. METHODS: This 3-year multicentre, prospective cohort study enrolled consecutive patients with bacteraemia by E. cloacae or K. aerogenes. Baseline characteristics, bacteraemia features (source, severity, treatment), antibiotic susceptibility, resistance mechanisms and mortality were analysed. RESULTS: The study included 285 patients with bacteraemia [196 (68.8%) E. cloacae and 89 (31.2%) K. aerogenes]. The groups showed no differences in age, sex, previous use of invasive devices, place of acquisition, sources or severity at onset. The Charlson score was higher among patients with E. cloacae bacteraemia [2 (1-4) vs. 1 (0.5-3); P = 0.018], and previous antibiotic therapy was more common in patients with K. aerogenes bacteraemia (57.3% vs. 41.3%; P = 0.01). Mortality was 19.4% for E. cloacae and 20.2% for K. aerogenes (P = 0.869). Antibiotic susceptibility was similar for both species, and the incidence of multidrug resistance or ESBL production was low (6% and 5.3%, respectively), with no differences between species. CONCLUSION: Bacteraemias caused by E. cloacae and K. aerogenes share similar patient profiles, presentation and prognosis. Patients with E. cloacae bacteraemia had more co-morbidities and those with K. aerogenes bacteraemia had received more antibiotics.


Assuntos
Bacteriemia , Enterobacter aerogenes , Infecções por Enterobacteriaceae , Bacteriemia/tratamento farmacológico , Enterobacter cloacae/genética , Infecções por Enterobacteriaceae/tratamento farmacológico , Infecções por Enterobacteriaceae/epidemiologia , Humanos , Estudos Prospectivos
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