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At least 19 recordsLinked to original sources
PubMed1986

Enterobacter asburiae sp. nov., a new species found in clinical specimens, and reassignment of Erwinia dissolvens and Erwinia nimipressuralis to the genus Enterobacter as Enterobacter dissolvens comb. nov. and Enterobacter nimipressuralis comb. nov.

Enterobacter asburiae sp. nov. is a new species that was formerly referred to as Enteric Group 17 and that consists of 71 strains, 70 of which were isolated from humans. Enterobacter asburiae sp. nov. strains gave positive reactions in tests for methyl red, citrate utilization (Simmons and Christensen's), urea hydrolysis, L-ornithine decarboxylase, growth in KCN, acid and gas production from D-glucose, and acid production from L-arabinose, cellobiose, glycerol (negative in 1 to 2 days, positive in 3 to 7 days), lactose, D-mannitol, alpha-methyl-D-glucoside, salicin, D-sorbitol, sucrose, trehalose, and D-xylose. They gave negative reactions in the Voges-Proskauer test and in tests for indole, H2S production, phenylalanine, L-lysine decarboxylase, motility, gelatin, utilization of malonate, lipase, DNase, tyrosine clearing, acid production from adonitol, D-arabitol, dulcitol, erythritol, i(myo)-inositol, melibiose, and L-rhamnose. They gave variable reactions in tests for L-arginine dihydrolase (25% positive after 2 days) and acid production from raffinose (69% positive after 2 days). Thirty-four Enterobacter asburiae sp. nov. strains were tested for DNA relatedness by the hydroxyapatite method with 32PO4-labeled DNA from the designated type strain (1497-78, ATCC 35953). The strains were 69 to 100% related in 60 degrees C reactions and 63 to 100% related in 75 degrees C reactions. Divergence within related sequences was 0 to 2.5%. Relatedness of Enterobacter asburiae sp. nov. to 84 strains of members of the Enterobacteriaceae was 5 to 63%, with closest relatedness to strains of Enterobacter cloacae, Erwinia dissolvens, Enterobacter taylorae, Enterobacter agglomerans, Erwinia nimipressuralis, and Enterobacter gergoviae. All strains tested were susceptible to gentamicin and sulfdiazine, and most were susceptible to chloramphenicol, colistin, kanamycin, nalidixic acid, carbenicillin and streptomycin. All strains were resistant to ampicillan, cephalothin, and penicillin, and most were resistant or moderately resistant to tetracycline. Enterobacter asburiae sp. nov strains were isolated from a variety of human sources, most prevalent of which were urine (16 strains), respiratory sources (15 strains), stools (12 strains), wounds (11 strains), and blood (7 strains). The clinical significance of Enterobacter aburiae is not known. As a result of this and previous studies, proposals are made to transfer Erwinia dissolvens and Erwinia nimipressuralis to the genus Enterobacter as Enterobacter dissolvens comb. nov. and Enterobacter nimipressuralis comb. nov., respectively.

Adult↗
PubMed2005

Reassignment of enterobacter dissolvens to Enterobacter cloacae as E. cloacae subspecies dissolvens comb. nov. and emended description of Enterobacter asburiae and Enterobacter kobei.

The taxonomic position of Enterobacter dissolvens was re-evaluated based on the analysis of the type strain ATCC 23373T and three clinical isolates. The strains were assigned to the genetic cluster of the species by phylogenetic sequence analysis in the frame of a recent population genetic study. The relatedness of E. dissolves to the other species of the E. cloacae complex was analyzed by DNA-DNA hybridization studies based on melting profiles in microplates. The genetic cluster of E. dissolvens fell into the same DNA-relatedness group like E. cloacae with mean deltaTm-values of 3.9 degrees C confirming the hybridization results of three former studies. Phenotypic analysis of the E. cloacae and E. dissolvens strains, respectively, based on 115 biochemical reactions yielded the esculin test as the only one differentiating between them by being positive for E. dissolvens and negative for E. cloacae strains. The name E. cloacae subsp. dissolvens comb. nov. is proposed for the group of organisms formerly referred to as E. dissolvens, and the name E. cloacae subsp. cloacae comb. nov. for the group of organisms formerly referred to as E. cloacae. The species descriptions of Enterobacter kobei and Enterobacter asburiae were emended based on the data collected on 17 and 15 strains, respectively. The strains were assigned to the respective species by a combination of phylogenetic sequence analyzes and DNA-DNA hybridizations. Phenotypic analyzes of 115 reactions gave detailed species profiles with new differentiating phenotypic properties.

Bacterial Typing Techniques↗
PubMed2002

Natural antibiotic susceptibility of Enterobacter amnigenus, Enterobacter cancerogenus, Enterobacter gergoviae and Enterobacter sakazakii strains.

OBJECTIVE: To investigate the natural susceptibility to 69 antimicrobial agents of 107 Enterobacter strains comprising E. amnigenus (n = 18), E. cancerogenus (n = 26), E. gergoviae (n = 28) and E. sakazakii (n = 35). METHODS: Minimal inhibitory concentrations (MICs) were determined with a microdilution procedure in Isosensitest broth and cation-adjusted Mueller-Hinton broth. RESULTS: All the species were naturally sensitive or intermediate to tetracyclines, amino-glycosides, numerous beta-lactams (acylureidopenicillins, ticarcillin, ampicillin/sulbactam, several cephalosporins, carbapenems, aztreonam), quinolones, antifolates, chloramphenicol and nitrofurantoin. Natural resistance was found to penicillin G, oxacillin, several macrolides, lincosamides, streptogramins, glycopeptides, rifampicin and fusidic acid. Species-related differences in natural susceptibility were found to some beta-lactams, azithromycin and fosfomycin. Whereas E. gergoviae was the most susceptible species to azithromycin, E. cancerogenus was most susceptible to fosfomycin and was the only species showing natural resistance to amoxicillin, amoxicillin/clavulanic acid, cefaclor, cefazoline, loracarbef and cefoxitin. There were only minor medium-dependent differences in susceptibility to most antibiotics. CONCLUSIONS: The present study establishes a database concerning the natural susceptibility of recently established Enterobacter species to a wide range of antibiotics, which can be applied for the validation of routine susceptibility test results. beta-Lactam susceptibility patterns indicate the expression of species-specific beta-lactamases expressed at high or low levels in all the species except E. sakazakii.

Anti-Bacterial Agents↗
PubMed2002

Chromosomal ampC genes in Enterobacter species other than Enterobacter cloacae, and ancestral association of the ACT-1 plasmid-encoded cephalosporinase to Enterobacter asburiae.

The amplification and sequence of ampC genes in Enterobacter asburiae, Enterobacter cancerogenus, Enterobacter dissolvens, Enterobacter hormaechei and Enterobacter intermedius bring the number of known cephalosporinase sequences from the genus Enterobacter to seven. Expression in Escherichia coli of the ampC genes from E. asburiae, E. hormaechei and E. intermedius established the functional nature of these genes. ampC from E. asburiae shows 96.5% identity to bla(ACT-1) encoding a plasmid-borne cephalosporinase previously believed to derive from Enterobacter cloacae. The reassignment of ACT-1 ancestry to E. asburiae is confirmed by the 95.5% identity between ampR upstream of bla(ACT-1) and ampR from E. asburiae.

Anti-Bacterial Agents↗
PubMed2002

Natural antibiotic susceptibility of Enterobacter spp., with special reference to Enterobacter aerogenes and Enterobacter intermedius strains.

The natural susceptibility to 71 antibiotics of 44 strains of Enterobacter aerogenes and 12 strains of Enterobacter intermedius was examined using a microdilution procedure in Isosensitest broth (for all strains) and cation-adjusted Mueller Hinton broth (for some strains). Both species were naturally sensitive or sensitive and intermediate to tetracyclines, all tested aminoglycosides, several penicillins and cephalosporins, carbapenems, aztreonam, quinolones, folate-pathway inhibitors, chloramphenicol and nitrofurantoin. Uniform natural resistance was found to cefoxitin and to antibiotics to which most other Enterobacteriaceae are also intrinsically resistant, e.g. several macrolides, lincosamides, streptogramins and glycopeptides. Major species-specific differences in susceptibility affecting clinical assessment criteria were found with amoxycillin, amoxycillin-clavulanate, some narrow-spectrum cephalosporins and fosfomycin. With the exception of penicillin G, oxacillin and cefoxitin, E. intermedius was naturally sensitive or naturally sensitive and intermediate (azlocillin) to all beta-lactams tested. Natural antibiotic susceptibility patterns of E. aerogenes and E. intermedius were analyzed with regard to the underlying mechanisms. The data were compared with the results from two recent studies dealing with natural susceptibilities of other clinically-relevant Enterobacter spp. With reference to beta-lactam susceptibility patterns, it can be assumed that all human-affecting Enterobacter species examined produce species-specific, chromosomally-encoded beta-lactamases of the AmpC type. The naturally-expressed amount of enzyme depends on the species.

Anti-Bacterial Agents↗
PubMedDate not supplied

[Application of gas chromatography in the identification of Enterobacter cloacae, Enterobacter aerogenes, and Enterobacter agglomerans].

Enterobacter cloacae, Enterobacter aerogenes and Enterobacter agglomerans were identified using gas chromatography as a substitution of the traditional techniques. Their acid methyl esters profiles were determined using a gas chromatograph Hewlett Packard 5890A and a RSL-150 heliflex capillary column. A total of 120 samples were analyzed from reference strains (ATCC 13047, 13048, 27155) and environmental isolations, eleven fatty acids were included in the profiles from which cis-9, 10-methyleneoctadecanoic acid (peak 24), cis-9-hexadecenoic acid (peak 14), octadecanoic acid (peak 23) and dodecanoic acid (peak 3), were the most important for the differentiation of the three species analyzed.

Bacteriological Techniques↗
PubMed1989

Enterobacter cancerogenus (Urosević, 1966) Dickey and Zumoff 1988, a senior subjective synonym of Enterobacter taylorae Farmer et al. (1985).

Strains labelled Enterobacter cancerogenus (Erwinia cancerogena) and strains labelled Enterobacter taylorae were found to constitute a single DNA-relatedness group (S1 nuclease hybridization method). Furthermore, no phenotypic test among the conventional and nutritional tests performed could differentiate Enterobacter cancerogenus from Enterobacter taylorae. Therefore, Enterobacter cancerogenus (Urosević, 1966) Dickey and Zumoff, 1968, is a senior subjective synonym for Enterobacter taylorae Farmer et al., 1985.

DNA, Bacterial↗
PubMed2005

Description of Enterobacter ludwigii sp. nov., a novel Enterobacter species of clinical relevance.

A new species, Enterobacter ludwigii, is presented on the basis of the characteristics of 16 strains, which were isolated from clinical specimens. These bacteria form a distinct genetic cluster in phylogenetic analyses of the population structure of the Enterobacter cloacae complex. As determined by DNA-DNA cross-hybridization experiments in microplates, this genetic cluster can be delineated from the other species of the E. cloacae complex with deltaTm values equal to or above 5 degrees C with Enterobacter hormaechei being the closest relative. The bacteria are gram-negative, fermentative, motile rods with the general characteristics of the genus Enterobacter and the E. cloacae complex in particular. E. ludwigii can be differentiated from the other Enterobacter species by its growth on myo-inositol and 3-0-methyl-D-glucopyranose. The type strain is EN-119 (= DSM 16688T = CIP 108491T).

Bacterial Typing Techniques↗
PubMed1996

Enterobacter kobei sp. nov., a new species of the family Enterobacteriaceae resembling Enterobacter cloacae.

The name Enterobacter kobei sp. nov. is proposed for a group of organisms referred to as NIH Group 21 at the National Institute of Health, Tokyo. The members of this species are Gram-negative, motile rods conforming to the definition of the family Enterobacteriaceae. The DNA relatedness of 23 strains of NIH Group 21 to the representative proposed as the type strain of this species averaged 82% at 70 degrees C, whereas the relatedness to other species within the family Enterobacteriaceae was less than 42%. Because the phenotypic resemblance to Enterobacter cloacae is very close and the DNA relatedness (12-42%) is closer to species of the genus Enterobacter than to other species of the family, the members of NIH Group 21 were placed in the genus Enterobacter. Close phenotypic and genetic relationships were also found between NIH Group 21 and a member of a group of organisms referred to as Enteric Group 69 at the Centers for Disease Control and Prevention (CDC), Atlanta, Georgia, USA. It is suggested that the latter could be regarded as a subspecific rank of E. kobei, though this is subject to study of further strains. The majority of strains of E. kobei were isolated from clinical specimens. A culture of the type strain (NIH 1485-79) has been deposited in the Japan Collection of Microorganisms as JCM 8580.

Bacteriological Techniques↗
PubMed2000

Detection of extended-spectrum beta-lactamases in clinical isolates of Enterobacter cloacae and Enterobacter aerogenes.

The aim of the present study was to investigate the frequency of extended-spectrum beta-lactamases (ESBLs) in a consecutive collection of clinical isolates of Enterobacter spp. The abilities of various screening methods to detect ESBLs in enterobacters were simultaneously tested. Among the 68 consecutive isolates (56 Enterobacter cloacae and 12 Enterobacter aerogenes isolates) that were analyzed for beta-lactamase content, 21 (25 and 58%, respectively) possessed transferable ESBLs with pIs of 8.2 and phenotypic characteristics of SHV-type enzymes, 8 (14.3%) of the E. cloacae isolates produced a previously nondescribed, clavulanate-susceptible ESBL that exhibited a pI of 6.9 and that conferred a ceftazidime resistance phenotype on Escherichia coli transconjugants, and 2 E. cloacae isolates produced both of these enzymes. Among the total of 31 isolates that were considered ESBL producers, the Vitek ESBL detection test was positive for 2 (6.5%) strains, and the conventional double-disk synergy test (DDST) with amoxicillin-clavulanate and with expanded-spectrum cephalosporins and aztreonam was positive for 5 (16%) strains. Modifications of the DDST consisting of closer application of the disks (at 20 instead of 30 mm), the use of cefepime, and the use of both modifications increased the sensitivity of this test to 71, 61, and 90%, respectively. Of the 37 isolates for which isoelectric focusing failed to determine ESBLs, the Vitek test was false positive for 1 isolate and the various forms of DDSTs were false-positive for 3 isolates.

Bacterial Typing Techniques↗
PubMed2002

prbA, a gene coding for an esterase hydrolyzing parabens in enterobacter cloacae and Enterobacter gergoviae strains.

The new gene prbA encodes an esterase responsible for the hydrolysis of the ester bond of parabens in Enterobacter cloacae strain EM. This gene is located on the chromosome of strain EM and was cloned by several PCR approaches. The prbA gene codes for an immature protein of 533 amino acids, the first 31 of which represent a proposed signal peptide yielding a mature protein of a putative molecular mass of 54.6 kDa. This enzyme presents analogies with other type B carboxylesterases, mainly of eukaryotic origin. The cloning and expression of the prbA gene in a strain of Escherichia coli previously unable to hydrolyze parabens resulted in the acquisition of a hydrolytic capacity comparable to the original activity of strain EM, along with an increased resistance of the transformed strain to methyl paraben. The presence of homologues of prbA was tested in additional ubiquitous bacteria, which may be causative factors in opportunistic infections, including Enterobacter gergoviae, Enterobacter aerogenes, Pseudomonas agglomerans, E. coli, Pseudomonas aeruginosa, and Burkholderia cepacia. Among the 41 total strains tested, 2 strains of E. gergoviae and 1 strain of Burkholderia cepacia were able to degrade almost completely 800 mg of methyl paraben liter(-1). Two strains of E. gergoviae, named G1 and G12, contained a gene that showed high homology to the prbA gene of E. cloacae and demonstrated comparable paraben esterase activities. The significant geographical distance between the locations of the isolated E. cloacae and E. gergoviae strains suggests the possibility of an efficient transfer mechanism of the prbA gene, conferring additional resistance to parabens in ubiquitous bacteria that represent a common source of opportunistic infections.

Amino Acid Sequence↗
PubMed1994

Detection of resistance due to inducible beta-lactamase in Enterobacter aerogenes and Enterobacter cloacae.

Thirty-six of 36 strains of Enterobacter cloacae and E. aerogenes with inducible beta-lactamase developed resistance when cefoxitin (inducer) was added to cefuroxime disks. Constitutive beta-lactamase producers (n = 23) were all resistant to cefuroxime. Cefuroxime resistance correlated with the amount of induced or constitutive beta-lactamase. Cefuroxime was a better indicator of induced resistance than cefamandole, cefazolin, cephalothin, ceftriaxone, cefotaxime, ticarcillin with or without clavulanic acid, or cefotetan. Induction by addition of cefoxitin to disks occasionally reduced zone sizes but not enough to change interpretations for ceftazidime, ceftizoxime, aztreonam, cefoperazone with or without sulbactam, and piperacillin with or without tazobactam. Most enterobacters were resistant to cefmetazole. The cefoxitin inducer-cefuroxime indicator method can be used in routine clinical laboratories to detect latent resistance due to chromosomally mediated inducible beta-lactamase in enterobacters.

Cefuroxime↗
PubMedDate not supplied

DNA relatedness between Enterobacter sakazakii and other members of the genus Enterobacter.

A DNA-DNA hybridization study (nitrocellulose filter method) was carried out with 13 strains of Enterobacter sakazakii and 38 strains belonging to other Enterobacter species (E. cloacae, E. amnigenus, E. intermedium and E. gergoviae). E. sakazakii strains were highly related (mean relative binding ratio +/- standard deviation: 89% +/- 10) to the strain R 16-76 (labelled DNA). No close relationship was found with the other Enterobacter species. The low relative binding ratios were not due to a difference in genome size (as shown by reciprocal binding experiments).

DNA, Bacterial↗
PubMedDate not supplied

Molecular epidemiology of a nosocomial outbreak due to Enterobacter cloacae and Enterobacter agglomerans in Campinas, São Paulo, Brazil.

A total of 73 isolates (57 Enterobacter cloacae and 16 Enterobacter agglomerans), recovered during an outbreak of bacteremia in the Campinas area, São Paulo, Brazil, were studied. Of these isolates, 61 were from parenteral nutrition solutions, 9 from blood cultures, 2 from a sealed bottle of parenteral nutrition solution, and one was of unknown origin. Of the 57 E. cloacae isolates, 54 were biotype 26, two were biotype 66 and one was non-typable. Of 39 E. cloacae isolates submitted to ribotyping, 87.2% showed the same banding pattern after cleavage with EcoRI and BamHI. No important differences were observed in the antimicrobial susceptibility patterns among E. cloacae isolates exhibiting the same biotype, serotype and ribotype. All E. agglomerans isolates, irrespective of their origin, showed same patterns when cleaved with EcoRI and BamHI. The results of this investigation suggest an intrinsic contamination of parenteral nutrition solutions and incriminate these products as a vehicle of infection in this outbreak.

Bacterial Typing Techniques↗
PubMed1995

Self-transmissible nif plasmid (pEA9) of Enterobacter agglomerans 339: molecular cloning and evidence for the existence of similar nif clusters on dissimilar plasmids in Enterobacter strains.

A cosmid library was generated to the 200-kb self-transmissible nif plasmid pEA9 isolated from Enterobacter agglomerans 339. The cosmid clone identified to contain the complete nif cluster was used to determine the nif gene organization and the physical map. The restriction pattern and nif gene organization of this nif cluster showed remarkable similarities to the nif cluster identified on the 110-kb plasmid pEA3 of Enterobacter agglomerans 333. Nucleotide sequence of several randomly selected regions of the nif cluster of pEA9 showed 96% similarity when compared to the known sequences of the nif cluster of pEA3. However, the homology ended abruptly at the flanking regions of the nif clusters and no similarity could be detected with the rest of the DNA of these plasmids. This reveals the existence of similar nif clusters on dissimilar plasmids, implying the horizontal transfer of the entire nif gene cluster.

Bacterial Proteins↗
PubMed1994

Taxonomic notes: synonymy of Enterobacter cancerogenus (Urosević 1966) Dickey and Zumoff 1988 and Enterobacter taylorae Farmer et al. 1985 and resolution of an ambiguity in the biochemical profile.

The descriptions of Enterobacter taylorae and Enterobacter cancerogenus show differences in key reactions (ornithine decarboxylase and D-sorbitol fermentation) that have not received attention and are inconsistent with the synonymy proposed by Grimont and Ageron (P. A. D. Grimont and E. Ageron, Res. Microbiol. 140:459-465, 1989). A reassessment of the biochemical properties confirms that they are synonymous. We believe that the priority of E. cancerogenus should be maintained in diagnostic and clinical microbiology even if the epithet could be misunderstood in a clinical setting.

Enterobacter↗
PubMed1999

Comparative in vitro activities of ciprofloxacin, clinafloxacin, gatifloxacin, levofloxacin, moxifloxacin, and trovafloxacin against Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter cloacae, and Enterobacter aerogenes clinical isolates with alterations in GyrA and ParC proteins.

The in vitro activities of ciprofloxacin, clinafloxacin, gatifloxacin, levofloxacin, moxifloxacin, and trovafloxacin were tested against 72 ciprofloxacin-resistant and 28 ciprofloxacin-susceptible isolates of Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter cloacae, and Enterobacter aerogenes. Irrespective of the alterations in GyrA and ParC proteins, clinafloxacin exhibited greater activity than all other fluoroquinolones tested against K. pneumoniae and E. aerogenes.

Anti-Infective Agents↗