Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Enterobacter”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 415 records · Page 23Linked to original sources
PubMed2006

Ceftobiprole medocaril (BAL5788) treatment of experimental Haemophilus influenzae, Enterobacter cloacae, and Klebsiella pneumoniae murine pneumonia.

Ceftobiprole (BAL9141) is an investigational cephalosporin active against methicillin- and vancomycin-resistant staphylococci administered as a water-soluble prodrug, ceftobiprole medocaril (BAL5788). Using an immunocompetent murine pneumonia model of Haemophilus influenzae, Enterobacter cloacae, or extended-spectrum beta-lactamase (ESBL) nonproducing or producing Klebsiella pneumoniae pneumonia, we compared results of treatment with ceftobiprole medocaril (71 mg/kg, sc, qid), ceftriaxone (50 mg/kg, im, bid), or cefepime (50 mg/kg, ip, q.i.d.). Results were expressed as median and 25th to 75th percentile log10 colony forming units per gram of lung tissue. Ceftobiprole, ceftriaxone, and cefepime were each more active than was no treatment and were equally active for treatment of experimental H. influenzae, E. cloacae, or ESBL-nonproducing K. pneumoniae pneumonia. For ESBL-producing K. pneumoniae, no differences were detected between no treatment and treatment with ceftobiprole, ceftriaxone, or cefepime. Ceftobiprole is active against H. influenzae, E. cloacae, and ESBL-nonproducing K. pneumoniae in an immunocompetent experimental murine pneumonia model.

Animals↗
PubMed2004

Enterobacter aerogenes OmpX, a cation-selective channel mar- and osmo-regulated.

The ompX gene of Enterobacter aerogenes was cloned. Its overexpression induced a decrease in the major porin Omp36 production and consequently a beta-lactam resistance was noted. Purified outer membrane protein X (OmpX) was reconstituted into artificial membranes and formed ion channels with a conductance of 20 pS in 1 M NaCl and a cationic selectivity. Both MarA expression and high osmolarity induced a noticeable increase of the OmpX synthesis in the E. aerogenes ATCC 13048 strain. In addition, OmpX synthesis increased under conditions in which the expression of the E. aerogenes major non-specific porins, Omp36 and Omp35, decreased.

Amino Acid Sequence↗
PubMed2004

Transgenic ice nucleation-active Enterobacter cloacae reduces cold hardiness of corn borer and cotton bollworm larvae.

The ice nucleation (IN) gene iceA of Erwinia ananas 110 was integrated into the chromosomes of two Enterobacter cloacae strains (Enc1.2022 and Enc1.181). These two newly derived transgenic strains, designated Enc2022-I and Enc181-I, respectively, possessed ice nucleation activity at -2.5 degrees C, significantly higher than their parent strains (active at approx -10 degrees C or lower). After ingesting these transgenic bacteria, the mean supercooling points (SCPs) of corn borer and cotton bollworm larvae were -3 to -4 degrees C, significantly higher than those of untreated controls. The SCPs remained significantly elevated over the 9-day period after ingestion, which matched well with the efficient gut colonization of the bacteria during this period. All treated larvae froze and eventually died after exposure for 6 h to a temperature of -7 degrees C, and more than 95% died after 12 h at -5 degrees C. In contrast, few or none of the untreated control larvae froze and died under the same conditions. Furthermore, the growth ability of these transgenic ice nucleation-active (INA) En. cloacae strains on corn leaves was reduced, compared to that of wild-type epiphytic E. ananas, as revealed by pot tests conducted in both greenhouse and outdoor conditions. The stable colonization in insect guts and their lower affinity to plants would make these transgenic INA bacteria useful as a novel tool for biological control of insect pests in agricultural fields.

Agriculture↗
PubMed2005

Rapid detection of a gfp-marked Enterobacter aerogenes under anaerobic conditions by aerobic fluorescence recovery.

A gfp- and kanamycin-resistance gene-containing plasmid pUCGK was successfully constructed and transformed into Enterobacter aerogenes to develop a rapid GFP-based method for quantifying the bacterial concentration under anaerobic conditions for production of biohydrogen. Since the use of GFP as a molecular reporter is restricted by its requirement for oxygen in the development of the fluorophore, fluorescence detection for the fluorescent E. aerogenes grown anaerobically for hydrogen production was performed by developing a method of aerobic fluorescence recovery (AFR) of the anaerobically expressed GFP. By using this AFR method, rapid and non-disruptive cell quantification of E. aerogenes by fluorescence density was achieved for analyzing the hydrogen production process.

Aerobiosis↗
PubMed2006

In vivo selection of Enterobacter aerogenes with reduced susceptibility to cefepime and carbapenems associated with decreased expression of a 40 kDa outer membrane protein and hyperproduction of AmpC beta-lactamase.

The mechanism(s) of resistance or decreased susceptibility to cefepime (FEP) and/or imipenem (IMP) in three consecutive isolates of Enterobacter aerogenes (Ea1, Ea2 and Ea3) cultured from bronchial aspirates of the same patient after treatment with ceftriaxone and FEP were studied. Identification was performed with the VITEK 2 system. All three isolates showed identical pulsed-field gel electrophoresis patterns and were resistant (minimum inhibitory concentrations (MICs)) to cefoxitin (MIC, >1024 mg/L), cefotaxime (CTX; MIC, 32-128 mg/L) and ceftazidime (CAZ; MIC, 32-128 mg/L) but susceptible to meropenem (MIC, Glu. Three outer membrane proteins (OMPs) of 51 kDa, 40 kDa and 38 kDa were observed in the three isolates by sodium dodecylsulphate-polyacrylamide gel electrophoresis (SDS-PAGE) (10% polyacrylamide gels with 4 M urea), although expression of the 40 kDa OMP was reduced in Ea2. In conclusion, decreased susceptibility to FEP and IMP in Ea2 is related to reduced expression of a 40 kDa OMP and hyperproduction of AmpC, whereas resistance to FEP in Ea3 is associated with hyperproduction of an altered AmpC.

Anti-Bacterial Agents↗
PubMed2006

Chloroquinolines block antibiotic efflux pumps in antibiotic-resistant Enterobacter aerogenes isolates.

Efflux mechanisms protect bacterial cells by pumping out toxic compounds and actively contribute to bacterial multidrug resistance. Agents inhibiting efflux pumps are of interest for the control of multidrug-resistant bacterial infections. Herein we report the effects of new chloroquinoline derivatives that render resistant Enterobacter aerogenes isolates noticeably more susceptible to structurally unrelated antibiotics. In addition, some of these chloroquinolines increase the intracellular concentration of chloramphenicol. Some of the molecules tested in this work are able to inhibit the main efflux pump (AcrAB-TolC), which is involved in E. aerogenes antibiotic resistance.

Anti-Bacterial Agents↗
PubMed2005

An Enterobacter cloacae toxin able to generate oxidative stress and to provoke dose-dependent lysis of leukocytes.

We investigated an Enterobacter cloacae strain exhibiting high hemolytic and leukotoxic activity. Monomeric and polymeric forms of the toxin showed similar effects on blood cells, although the polymer was more active than the monomer. Fluorescence microscopy revealed that both forms of the FITC-labeled toxin interacted with leukocytes, principally with neutrophils. Prelytic concentrations of polymeric and monomeric toxin significantly increased the production of reactive oxygen species (ROS) in neutrophils. Conversely, lytic concentrations of both toxin forms showed an increase followed by a decrease of ROS due to neutrophil damage. Monocytes did not show oxidative stress at all the toxin concentrations assayed. The toxin-neutrophil interaction at prelytic concentrations of toxin-stimulated ROS production and led to oxidative stress with subsequent cell death by apoptosis. However, high concentrations of E. cloacae toxin damaged leukocytes, producing lysis before the trigger of apoptosis, which suggests that the toxic effect is concentration dependent. The inhibition of oxidative stress observed with genistein and chloroquine suggests a potential involvement of the tyrosine kinase and nitric oxide synthesis pathways in E. cloacae toxin-mediated elevation of ROS.

Apoptosis↗
PubMed2026

Functional identification of the key gene Eh-fadB in nicosulfuron degradation by Enterobacter hormaechei ES1 based on multi-omics and enzymatic characterization.

Nicosulfuron is a sulfonylurea herbicide with residues that pose ecological risks in agricultural soils. Here we elucidated the degradation mechanism of Enterobacter hormaechei ES1 through whole-genome sequencing, transcriptomics, metabolomics, gene knockout, heterologous expression, and soil bioremediation assays. Under nicosulfuron stress, ES1 upregulated antioxidant enzymes including SOD, POD, and CAT, along with glutathione synthesis, to scavenge excess reactive oxygen species. HPLC-TOF-MS identified degradation intermediates such as ADMP and ASDM, indicating initial cleavage of the sulfonylurea bridge. Integrated multi-omics prioritized Eh-fadB, encoding a fatty acid β-oxidation multifunctional enzyme, as a novel degradative gene. Targeted knockout of Eh-fadB reduced nicosulfuron degradation from 87.6% to 37.04%, while genetic complementation restored nearly full activity. Purified Eh-FadB directly converted nicosulfuron, with optimal performance at 30 °C and pH 5-6; its activity was enhanced by Na+ and Pb2+ but inhibited by Fe3+. Molecular docking and dynamics identified His-450 and Asn-427 as key residues for substrate binding. In contaminated soil, inoculation with ES1 reduced nicosulfuron content within 21 days and promoted recovery of dehydrogenase and urease activities. This study provides the first genetic and biochemical evidence that a FadB-type enzyme participates in nicosulfuron catabolism, supporting sulfonylurea bridge cleavage and its potential for soil bioremediation.

Eh-fadB↗
PubMed2004

Emergence of Enterobacter cloacae as a common pathogen in neonatal units: pulsed-field gel electrophoresis analysis.

In the first week of December 2002, three infants hospitalized in the neonatal department of our hospital had blood cultures positive with Enterobacter cloacae. Screening cultures and genotyping showed that 10 of 25 screened patients also carried E. cloacae and that nine isolates belonged to the same clone as that responsible for all three bacteraemias. This epidemic cluster was limited to one of the two units of the department. Surveillance of both units continued until the end of March 2003; 51 of 159 neonates screened were colonized with E. cloacae, 38 out of 80 (47.5%) in the premature unit (PU) and 13 out of 79 (16.4%) in the paediatric intensive care unit (PICU). Pulsed-field gel electrophoresis (PFGE) analysis of 130 available isolates revealed 30 different pulsotypes, including 24 unique pulsotypes from individual patients and six from multiple patients. Antibiotic (particularly beta-lactam) use did not significantly vary from 1999 to 2003. The consumption of alcohol-based hand rub (four-fold higher in the PICU than in the PU) and nurse-to-patient ratio (1:2 in the PICU and 1:4 in the PU) might explain the higher cross-transmission rate in the PU. Finally, despite an epidemiological survey, we failed to identify the causes of the emergence of E. cloacae in our neonatology units. However, improved hygiene practices combined with restriction of admission led to the progressive disappearance of the epidemic strain. The increasing importance of this type of unit and the dramatic consequences of infections emphasize the need for additional research on the constitution of the flora of newborns and the mode of acquisition Gram-negative multi-resistant bacteria.

Anti-Bacterial Agents↗
PubMed2004

Nosocomial and community-acquired Enterobacter cloacae bloodstream infection: risk factors for and prevalence of SHV-12 in multiresistant isolates in a medical centre.

In a medical centre in northern Taiwan, 60 patients had bloodstream infection caused by Enterobacter cloacae from 1 January 2002 to 30 April 2003. Forty (66.7%) were nosocomial and 26 were caused by multiresistant isolates. Twenty patients died due to the infection. Central venous catheterization and mechanical ventilation were relative risks for nosocomial E. cloacae infection. Age and mechanical ventilation were risk factors for multiresistant E. cloacae infection. Mortality was associated with multiresistant isolates and polymicrobial infection. Pulsed-field gel electrophoresis (PFGE) analysis showed, the 26 multiresistant isolates comprised 12 different types, with type A predominating (12 isolates). Excluding the patients infected with PFGE type A, central venous catheterization was a relative risk for infection, and polymicrobial infection was a risk factor for mortality. All but one of the 26 multiresistant isolates had the extended-spectrum beta-lactamase SHV-12. TEM-1 and ampC beta-lactamase genes were also detected in 25 of the 26 multiresistant isolates. Southern blotting indicated that the SHV-12 gene was located on plasmids. Eleven of the 26 multiresistant isolates had minimum inhibitory concentrations (MIC) > or =16 mg/L for cefepime, which was reduced by the addition of sulbactam for most isolates, resulting in susceptibility. The combination of cefepime and sulbactam may be effective in the treatment of multiresistant E. cloacae bloodstream infection.

Adolescent↗
PubMed2006

An outbreak of wound infection in cardiac surgery patients caused by Enterobacter cloacae arising from cardioplegia ice.

This paper describes an outbreak of postoperative sternal wound infections. A cardiac surgeon noted a cluster of serious infections leading to wound dehiscence, despite the fact that none of his colleagues had noticed a rise in infection rates. The infections were predominantly with Enterobacter cloacae, and molecular typing and serotyping showed these isolates to be indistinguishable. Observation of the surgeon's practice revealed nothing untoward, and there were no infections among his patients operated on in another hospital. There appeared to be no significant difference between the modes of operation of the different surgeons. The operating theatres were screened to exclude an environmental source, with samples cultured on CHROMagar Orientation, a selective/differential medium designed for urine samples. Further questioning revealed one difference between the practices of the different surgeons; this surgeon used semi-frozen Hartmann's solution to achieve cardioplegia. The freezer used for this was swabbed and yielded E. cloacae, indistinguishable from the clinical isolates. It is hypothesized that this organism contaminated the freezer, and that the contamination was passed on to the ice/slush solution, thus infecting the patients. There have been no more cases since the freezer was replaced, a rigorous cleaning schedule instituted, and steps taken to reduce the possibility of any further contamination.

Cardiovascular Surgical Procedures↗
PubMed2026

Gene transfer from NDM-5-producing and OXA-48-producing Enterobacter hormaechei ST79 on contaminated dicloxacillin capsules to other Enterobacterales in Europe, 2020-23: a retrospective, observational, molecular epidemiological study.

BACKGROUND: In February, 2023, an outbreak of Enterobacter hormaechei ST79 carrying blaNDM-5 and blaOXA-48 was linked to contaminated dicloxacillin capsules administered to approximately 79 000 individuals in Denmark. Initial clonal outbreak investigations identified 11 patients with the E hormaechei ST79 outbreak strain, which carried blaNDM-5 on a distinct IncX3 plasmid, and in nine cases, blaOXA-48 was on a distinct IncL plasmid. Interspecies plasmid transfer was observed in one patient, suggesting a potential plasmid-mediated outbreak involving other Enterobacterales. However, no studies have characterised the progression of a clonal outbreak originating from a contaminated medicine into plasmid-mediated dissemination of carbapenemase genes. Hence, we aimed to characterise the clonal and plasmid-mediated spread of carbapenemase genes in this outbreak. METHODS: We conducted a retrospective genomic and epidemiological investigation using existing short-read whole-genome sequencing data from all carbapenemase-producing Enterobacterales (CPE) from the Danish national surveillance, collected between Jan 1, 2014, and Oct 1, 2023. All confirmed CPE isolates were eligible for inclusion. Using in-silico screening for unique fragments of the two outbreak plasmids, we selected 160 isolates for long-read sequencing to obtain complete plasmid sequences for outbreak investigation. Analyses were descriptive and included comparison of sequence identity and coverage to define outbreak-associated plasmids and summary statistics of patient characteristics. FINDINGS: Data from 1829 isolates were obtained. We detected 16 of 53 isolates involved in the outbreak using conventional outbreak detection methods. The remaining 37 isolates were detected using plasmid-specific screening and long-read sequencing. 15 patients carried the outbreak E hormaechei strain, including the 11 patients previously reported. Three of the 15 patients presented with at least one additional bacterial species carrying one or both outbreak plasmids (pDcap_OXA-48 and pDcap_NDM-5). A further 24 patients, sampled between July 1, 2020, and Oct 1, 2023, presented with other Enterobacterales carrying one or both outbreak-associated plasmids but not the original E hormaechei ST79 strain. In four cases, outbreak-associated plasmids differed structurally from the original outbreak plasmid. INTERPRETATION: This study describes how a clonal CPE outbreak caused by a contaminated medicine evolved into a complex plasmid-mediated outbreak involving multiple Enterobacterales species. Most patients related to the outbreak did not present with the original E hormaechei ST79 outbreak strain and were therefore not identified using standard outbreak detection methods. These findings highlight the importance of using plasmid-focused approaches in outbreak investigations. FUNDING: The Danish Ministry of Health, SSI-Seq (cofunded by EU4Health).

Humans↗
PubMed2004

Accumulation of hexavalent chromium by an exopolysaccharide producing marine Enterobacter cloaceae.

An exopolysaccharide producing Enterobacter cloaceae (AK-I-MB-71a) was tested for its Cr (VI) tolerance. This isolate was not only resistant to this heavy metal but also showed enhanced growth and exopolysaccharide production in the presence of Cr (VI) at 25, 50 and 100 ppm concentrations. XRF analysis of both the biomass as well as the exopolysaccharide revealed that a sum total of about 60-70% chromium was accumulated by this bacterium. This indicated that this organism could prove to be a potential candidate in the field of bioremediation with respect to chromium removal.

Biomass↗
PubMed2004

[Outbreak of Enterobacter aerogenes in paediatric unit].

Within the framework of breast milk control the hygiene laboratory of Brest hospital isolates, on 3 January 1996 a strain of Enterobacter aerogenes secretory of cephalosporinase in the breast milk of a mother whose child was hospitalized in neonatalogy. On 15 April 1996 a new strain of E. aerogenes is isolated from another mother's breast milk. Until 18 August 1997, 21 samples of breast milk were tested positive to this bacteria. During the same period, E. aerogenes was isolated in 26 children under 1 year of age, 11 of which were infected and 15 colonized. The breast milk did not correspond to those of the mothers of the infected or colonized children. All the strains presented the same antibioresistance. The pulsed-field gel electrophoresis showed that the children's strains, those colonized or infected as well as those isolated in breast milk had the same restriction profile. The epidemiological study concerned the biberonnery-lactarium. The biberonnery's staff is the same as the staff of the lactarium. A portage was searched for among the members of the staff of these units, but without success. The search for E. aerogenes in the environment and in baby-food, others than breast milk was negative. Finally, we did not find any source for these contagions. The only hypothesis we have retained is that of a common source from the biberonnery-lactarium, but without being able to bring any proof to it. Following this epidemic, we have revised all the working modalities and practices with the staff of the biberonnery-lactarium.

Disease Outbreaks↗
PubMed2005

Pore formation, polymerization, hemolytic and leukotoxic effects of a new Enterobacter cloacae toxin neutralized by antiserum.

A new toxin of Enterobacter cloacae was purified and studied by SDS-PAGE electrophoresis with the purpose of investigating its ability to generate polymers and their molecular mass. Monomer of 13.3 kDa and structures of multimeric mass were detected. The toxin of 66 kDa was the most abundant form of toxin. This polymer and the monomer were selected to examine blood cells damage. Membrane pores caused by both toxin forms seemed to be of similar dimension (estimated in 3.6 nm by experiments with osmotic protectors) and were able to lyse erythrocytes and leukocytes. The results obtained indicate that polymerization and pore formation are involved in the molecular events that participate in the cytotoxic effects of E. cloacae toxin. Immunization of rabbits with 13.3kDa toxin generated antibody response capable of inhibiting oxidative stress as well as hemolytic and leukotoxic effects. Immunoblotting indicated that monomer and polymer reacted with antihemolysin serum. The importance of E. cloacae toxin "in vivo" was studied in animals by means of assays performed in peritoneum of rats, inoculated with the hemolytic strain (C1) and a non-hemolytic variant (C4). Both strains stimulated infiltration of leukocytes in peritoneum, but C1 caused cell death and lysis wheras assays with C4 maintained the viability of leukocytes even within 5 h after extraction of samples.

Animals↗
PubMed2005

Purification and characterization of thermoalkalophilic xylanase isolated from the Enterobacter sp. MTCC 5112.

Thermoalkalophilic Enterobacter sp. MTCC 5112 was isolated from a sediment sample collected from the Mandovi estuary on the west coast of India. This culture produced extracellular xylanase. The xylanase enzyme was isolated by ammonium sulfate (80%) fractionation and purified to homogeneity using size exclusion and ion exchange chromatography. The molecular mass of the xylanase was approximately 43 kDa. The optimal pH of the xylanase activity was 9, and at room temperature it showed 100% stability at pH 7, 8 and 9 for 3 h. The optimal temperature for the enzyme activity was 100 degrees C at pH 9.0. At 80 degrees C and pH 9, 90% of the enzyme activity was retained after 40 min. At 70 and 60 degrees C, the enzyme retained 64% and 85% of its activity after 18 h, respectively, while at 50 degrees C and pH 9 the enzyme remained stable for days. For xylan, the enzyme gave a K(m) value of 3.3 mg ml(-1) and a V(max) value of 5,000 micromol min(-1) mg(-1) when the reaction was carried out at 100 degrees C and pH 9. In the presence of metal ions such as Co(2+), Zn(2+), Fe(2+), Cu(2+), Mg(2+) and Ca(2+) the activity of the enzyme increased, whereas strong inhibition of enzyme activity was observed in the presence of Hg(2+) and EDTA. To the best of our knowledge, this is the first report on the production of xylanase by this bacterium.

Bacterial Proteins↗
PubMed2006

Use of flow cytometry for analysis of phage-mediated killing of Enterobacter aerogenes.

In this study, the use of flow cytometry to analyze phage-mediated killing of Enterobacter aerogenes under varying conditions of temperature and nutrient availability was assessed. Bacteriophage UZ1, specific for an E. aerogenes strain, was applied at a multiplicity of infection (MOI) of 1 and 1000 to a Teflon surface, artificially infected with its host at a level of 4.5 log cells. After incubation for 20 h, bacteriophages were quantified using the soft agar layer method. For the quantification of bacterial cells, plate counting and flow cytometric analysis of live/dead stained cells were performed in parallel. At an MOI of 1, phage treatment was successful only after incubation under nutrient-rich conditions at 37 degrees C: E. aerogenes cells were not detected and a tenfold increase in phage UZ1 was observed. At a MOI of 1000, no E. aerogenes cells could be cultured after incubation at 37 and 4 degrees C. However, flow cytometric analysis revealed that lysis did not occur at 4 degrees C but was achieved during subsequent plate culture. In conclusion, the use of flow cytometry enabled identification of culture-based bias during plate culture. The flow cytometric assay used in this study proved to be rapid, as this culture-independent method does not require lengthy incubation periods post-sampling. The bacteriophage-mediated killing of E. aerogenes cells on Teflon surfaces indicated that disinfection of E. aerogenes with bacteriophage UZ1 can be successful when high MOIs are achieved, while at low multiplicities of infection conditions favorable for phage replication are required.

Bacteriolysis↗
PubMed2005

Removal of selenium from river water by a microbial community enhanced with Enterobacter taylorae in organic carbon coated sand columns.

Discovering an effective means to remove selenium (Se) from Se-contaminated water is fundamental in minimizing environmental contamination and ensuring wildlife protection. In this study, Enterobacter taylorae attached to tryptic soy agar (TSA) coatings was used in sand columns to remove Se from a natural river water. During 80 days of the experiment, E. taylorae and indigenous Se(VI) reducers in the water used organic carbon coatings to effectively reduce Se(VI) to Se(0). About 95% and 70% of the influent Se (469 microg/L) was reduced to Se(0), respectively, in the columns with and without E. taylorae and 94--98% of the newly formed Se(0) was trapped in the columns. Analysis of Se species in effluent at the end of the experiment revealed that organic Se from the columns with E. taylorae was similar to that in influent (0.567 microg/L). This study indicates that using organic coatings attached with Se(VI) reducers in a biotreatment system may be a potentially feasible method to remove Se from Se-contaminated water in field.

Adsorption↗