Genome analysis and identification of gelatinase encoded gene in Enterobacter aerogenes

NASA Astrophysics Data System (ADS)

Shahimi, Safiyyah; Mutalib, Sahilah Abdul; Khalid, Rozida Abdul; Repin, Rul Aisyah Mat; Lamri, Mohd Fadly; Bakar, Mohd Faizal Abu; Isa, Mohd Noor Mat

2016-11-01

In this study, bioinformatic analysis towards genome sequence of E. aerogenes was done to determine gene encoded for gelatinase. Enterobacter aerogenes was isolated from hot spring water and gelatinase species-specific bacterium to porcine and fish gelatin. This bacterium offers the possibility of enzymes production which is specific to both species gelatine, respectively. Enterobacter aerogenes was partially genome sequenced resulting in 5.0 mega basepair (Mbp) total size of sequence. From pre-process pipeline, 87.6 Mbp of total reads, 68.8 Mbp of total high quality reads and 78.58 percent of high quality percentage was determined. Genome assembly produced 120 contigs with 67.5% of contigs over 1 kilo base pair (kbp), 124856 bp of N50 contig length and 55.17 % of GC base content percentage. About 4705 protein gene was identified from protein prediction analysis. Two candidate genes selected have highest similarity identity percentage against gelatinase enzyme available in Swiss-Prot and NCBI online database. They were NODE_9_length_26866_cov_148.013245_12 containing 1029 base pair (bp) sequence with 342 amino acid sequence and NODE_24_length_155103_cov_177.082458_62 which containing 717 bp sequence with 238 amino acid sequence, respectively. Thus, two paired of primers (forward and reverse) were designed, based on the open reading frame (ORF) of selected genes. Genome analysis of E. aerogenes resulting genes encoded gelatinase were identified.

The differential importance of mutations within AmpD in cephalosporin resistance of Enterobacter aerogenes and Enterobacter cloacae.

PubMed

Babouee Flury, Baharak; Ellington, Matthew J; Hopkins, Katie L; Turton, Jane F; Doumith, Michel; Woodford, Neil

2016-11-01

Mechanisms leading to carbapenem and cephalosporin resistance were sought in Enterobacter aerogenes isolates that were highly resistant to carbapenems but had no known carbapenemase. Results were compared with recent work examining carbapenem-resistant Enterobacter cloacae. Eighteen carbapenem-resistant E. aerogenes were screened for known β-lactamase and carbapenemase genes, and novel carbapenemases were sought in whole-genome sequencing (WGS) data of the three most resistant isolates. For all isolates, ampC, ampR, ampD and the porin genes omp35 and omp36 were investigated by Sanger sequencing or from available WGS data. Expression of ampC and porin genes was measured in comparison with cephalosporin- and carbapenem-susceptible control strains by reverse transcriptase PCR, with porin translation also detected by SDS-PAGE. Loss of Omp35, primarily due to decreased transcription (up to 250×), was observed in ertapenem-resistant isolates (MICs ≥ 2 mg/L), whereas meropenem resistance (MICs ≥ 4 mg/L) was observed in those isolates also showing decreased or no production of Omp36. Loss of Omp36 was due to combinations of premature translation termination or reduced transcription. In contrast to E. cloacae, cephalosporin resistance in E. aerogenes was not associated with lesions in AmpD. High-level cefepime resistance (MIC = 32 mg/L) was caused by a novel modification in the H-10 helix of AmpC in one isolate. The differential importance of AmpD lesions in cephalosporin resistance in E. cloacae and E. aerogenes underlines the differences between these contrasting members of the Enterobacter genus. Porin loss resulted in high-level carbapenem resistance with gradual loss of Omp36, which led to high-level meropenem resistance. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

Irreproducible and Uninterpretable Polymyxin B MICs for Enterobacter cloacae and Enterobacter aerogenes

PubMed Central

Landman, David; Salamera, Julius

2013-01-01

Carbapenem-resistant Enterobacter species are emerging nosocomial pathogens. As with most multidrug-resistant Gram-negative pathogens, the polymyxins are often the only therapeutic option. In this study involving clinical isolates of E. cloacae and E. aerogenes, susceptibility testing methods with polymyxin B were analyzed. All isolates underwent testing by the broth microdilution (in duplicate) and agar dilution (in duplicate) methods, and select isolates were examined by the Etest method. Selected isolates were also examined for heteroresistance by population analysis profiling. Using a susceptibility breakpoint of ≤2 μg/ml, categorical agreement by all four dilution tests (two broth microdilution and two agar dilution) was achieved in only 76/114 (67%) of E. cloacae isolates (65 susceptible, 11 resistant). Thirty-eight (33%) had either conflicting or uninterpretable results (multiple skip wells, i.e., wells that exhibit no growth although growth does occur at higher concentrations). Of the 11 consistently resistant isolates, five had susceptible MICs as determined by Etest. Heteroresistant subpopulations were detected in eight of eight isolates tested, with greater percentages in isolates with uninterpretable MICs. For E. aerogenes, categorical agreement between the four dilution tests was obtained in 48/56 (86%), with conflicting and/or uninterpretable results in 8/56 (14%). For polymyxin susceptibility testing of Enterobacter species, close attention must be paid to the presence of multiple skip wells, leading to uninterpretable results. Susceptibility also should not be assumed based on the results of a single test. Until the clinical relevance of skip wells is defined, interpretation of polymyxin susceptibility tests for Enterobacter species should be undertaken with extreme caution. PMID:24088860

Acanthamoeba castellanii of the T4 genotype is a potential environmental host for Enterobacter aerogenes and Aeromonas hydrophila

PubMed Central

2013-01-01

Background Acanthamoeba can interact with a wide range of microorganisms such as viruses, algae, yeasts, protists and bacteria including Legionella pneumophila, Pseudomonas aeruginosa, Vibrio cholerae, Helicobacter pylori, Listeria monocytogenes, Mycobacterium spp., and Escherichia coli. In this capacity, Acanthamoeba has been suggested as a vector in the transmission of bacterial pathogens to the susceptible hosts. Methods Here, we used a keratitis isolate of A. castellanii of the T4 genotype and studied its interactions with two bacterial genera which have not been tested before, Enterobacter aerogenes, and Aeromonas hydrophila, as well as E. coli. Assays were performed to determine bacterial association with and invasion of A. castellanii. Additionally, bacterial survival intracellular of A. castellanii trophozoites as well as cysts was determined. Results All three bacterial isolates tested, associated, invaded, and survived inside A. castellanii trophozoites as well as A. castellanii cysts. However, E. aerogenes and E. coli exhibited significantly reduced association with and invasion of A. castellanii as compared with A. hydrophila (P < 0.01 using paired T-test, one tail distribution). In the long term survival assays, all three bacterial isolates tested remained viable inside A. castellanii trophozoites, while amoeba remained intact; however A. hydrophila exhibited higher survival inside amoebae (14.54 ± 3.3 bacteria:amoeba ratio) compared with E. aerogenes (3.96 ± 0.7 bacteria:amoeba ratio) and E. coli (5.85 ± 1.1 bacteria:amoeba ratio). A. hydrophila, E. coli, and E. aerogenes remained viable during the encystment process and exhibited higher levels of recovery from mature cysts (14.13 ± 0.89 A. hydrophila:amoeba ratio, 10.13 ± 1.17 E. aerogenes:amoeba ratio, and 11.95 ± 0.7 E. coli:amoeba ratio). Conclusions A. hydrophila and E. aerogenes also joined the ranks of other bacteria that could benefit from A. castellanii

Acanthamoeba castellanii of the T4 genotype is a potential environmental host for Enterobacter aerogenes and Aeromonas hydrophila.

PubMed

Yousuf, Farzana Abubakar; Siddiqui, Ruqaiyyah; Khan, Naveed Ahmed

2013-06-07

Acanthamoeba can interact with a wide range of microorganisms such as viruses, algae, yeasts, protists and bacteria including Legionella pneumophila, Pseudomonas aeruginosa, Vibrio cholerae, Helicobacter pylori, Listeria monocytogenes, Mycobacterium spp., and Escherichia coli. In this capacity, Acanthamoeba has been suggested as a vector in the transmission of bacterial pathogens to the susceptible hosts. Here, we used a keratitis isolate of A. castellanii of the T4 genotype and studied its interactions with two bacterial genera which have not been tested before, Enterobacter aerogenes, and Aeromonas hydrophila, as well as E. coli. Assays were performed to determine bacterial association with and invasion of A. castellanii. Additionally, bacterial survival intracellular of A. castellanii trophozoites as well as cysts was determined. All three bacterial isolates tested, associated, invaded, and survived inside A. castellanii trophozoites as well as A. castellanii cysts. However, E. aerogenes and E. coli exhibited significantly reduced association with and invasion of A. castellanii as compared with A. hydrophila (P < 0.01 using paired T-test, one tail distribution). In the long term survival assays, all three bacterial isolates tested remained viable inside A. castellanii trophozoites, while amoeba remained intact; however A. hydrophila exhibited higher survival inside amoebae (14.54 ± 3.3 bacteria:amoeba ratio) compared with E. aerogenes (3.96 ± 0.7 bacteria:amoeba ratio) and E. coli (5.85 ± 1.1 bacteria:amoeba ratio). A. hydrophila, E. coli, and E. aerogenes remained viable during the encystment process and exhibited higher levels of recovery from mature cysts (14.13 ± 0.89 A. hydrophila:amoeba ratio, 10.13 ± 1.17 E. aerogenes:amoeba ratio, and 11.95 ± 0.7 E. coli:amoeba ratio). A. hydrophila and E. aerogenes also joined the ranks of other bacteria that could benefit from A. castellanii. Because cysts can be airborne, these

KPC-producing Enterobacter aerogenes infection.

PubMed

Tuon, Felipe F; Scharf, Camila; Rocha, Jaime L; Cieslinsk, Juliette; Becker, Guilherme Nardi; Arend, Lavinia N

2015-01-01

Enterobacter is a common nosocomial microorganism and its carbapenem's resistance has increased. The management of these cases is unclear. We evaluated 16 patients with KPC-producing Enterobacter aerogenes infections, detailing the site of infection, therapy, clinical and epidemiological data. A retrospective and descriptive study. Clinical data were revised and KPC-2 detection was by molecular methods. Risk factors associated with mortality were compared using appropriate tests according to variable type with a significance level of 0.05. The 30-day mortality rate was 37.5% with no association with inadequate treatment. Age (p=0.004) and Charlson score of comorbidities (p=0.048) were independent risk factors associated with death in the multivariate analysis. The odds ratio for age >43 years was 3.00 (95% CI: 1.02-9.32) and for Charlson score >3 was 2.00 (95% CI: 1.08-3.71). Five strains were pan-resistant based on automated susceptibility tests. All patients were treated with monotherapy. The clinician should be alert to carbapenem-resistant Enterobacteriaceae infection in older patients with comorbidities. The mortality is high and we believe that prompt and adequate therapy must be employed. Copyright © 2015 Elsevier Editora Ltda. All rights reserved.

TEM Derivative-Producing Enterobacter aerogenes Strains: Dissemination of a Prevalent Clone

PubMed Central

Dumarche, P.; De Champs, C.; Sirot, D.; Chanal, C.; Bonnet, R.; Sirot, J.

2002-01-01

TEM-24 (CAZ-6) extended-spectrum β-lactamase (ESBL) was detected in 1988 in Clermont-Ferrand, France, in Klebsiella pneumoniae (blaTEM-24) and Enterobacter aerogenes (blaTEM-24b), and since 1994, a TEM-24-producing E. aerogenes clonal strain has been observed elsewhere in the country. To determine if the spread of this clonal strain was restricted to TEM-24-producing E. aerogenes strains, 84 E. aerogenes strains (non-TEM/SHV-producing strains, TEM-1- or -2-producing strains, and different ESBL-producing strains), isolated from 1988 to 1999 in Clermont-Ferrand (n = 59) and in 11 other French hospitals in 1998 (n = 25), were studied. A clonal strain was found for TEM-24- but also for TEM-3- and TEM-1- or 2-producing isolates. This study shows that there is a clonal strain dependent on acquisition of the TEM-type enzyme (TEM-24 and other TEM types). PMID:11897606

Production of L-lactic acid from metabolically engineered strain of Enterobacter aerogenes ATCC 29007.

PubMed

Thapa, Laxmi Prasad; Lee, Sang Jun; Park, Chulhwan; Kim, Seung Wook

2017-07-01

In this study, L-lactic acid production was investigated from metabolically engineered strain of E. aerogenes ATCC 29007. The engineered strain E. aerogenes SUMI01 (Δpta) was generated by the deletion of phosphate acetyltransferase (pta) gene from the chromosome of E. aerogenes ATCC 29007 and deletion was confirmed by colony PCR. Under the optimized fermentation conditions, at 37°C and pH 6 for 84h, the L-lactic acid produced by engineered strain E. aerogenes SUMI01 (Δpta) in flask fermentation using 100g/L mannitol as the carbon source was 40.05g/L as compared to that of the wild type counterpart 20.70g/L. At the end of the batch fermentation in bioreactor the production of L-lactic acid reached to 46.02g/L and yield was 0.41g/g by utilizing 112.32g/L mannitol. This is the first report regarding the production of L-lactic acid from Enterobacter species. We believe that this result may provide valuable guidelines for further engineering Enterobacter strain for the improvement of L-lactic acid production. Copyright © 2017 Elsevier Inc. All rights reserved.

Study of the role of anaerobic metabolism in succinate production by Enterobacter aerogenes.

PubMed

Tajima, Yoshinori; Kaida, Kenichi; Hayakawa, Atsushi; Fukui, Keita; Nishio, Yousuke; Hashiguchi, Kenichi; Fudou, Ryosuke; Matsui, Kazuhiko; Usuda, Yoshihiro; Sode, Koji

2014-09-01

Succinate is a core biochemical building block; optimizing succinate production from biomass by microbial fermentation is a focus of basic and applied biotechnology research. Lowering pH in anaerobic succinate fermentation culture is a cost-effective and environmentally friendly approach to reducing the use of sub-raw materials such as alkali, which are needed for neutralization. To evaluate the potential of bacteria-based succinate fermentation under weak acidic (pH <6.2) and anaerobic conditions, we characterized the anaerobic metabolism of Enterobacter aerogenes AJ110637, which rapidly assimilates glucose at pH 5.0. Based on the profile of anaerobic products, we constructed single-gene knockout mutants to eliminate the main anaerobic metabolic pathways involved in NADH re-oxidation. These single-gene knockout studies showed that the ethanol synthesis pathway serves as the dominant NADH re-oxidation pathway in this organism. To generate a metabolically engineered strain for succinate production, we eliminated ethanol formation and introduced a heterogeneous carboxylation enzyme, yielding E. aerogenes strain ΔadhE/PCK. The strain produced succinate from glucose with a 60.5% yield (grams of succinate produced per gram of glucose consumed) at pH <6.2 and anaerobic conditions. Thus, we showed the potential of bacteria-based succinate fermentation under weak acidic conditions.

Sepsis resulting from Enterobacter aerogenes resistant to carbapenems after liver transplantation.

PubMed

Chen, Hao; Zhang, Ying; Chen, Ya-Gang; Yu, Yun-Song; Zheng, Shu-Sen; Li, Lan-Juan

2009-06-01

Sepsis due to Enterobacter aerogenes (E. aerogenes) is rare after liver transplantation but is also a serious infection that may cause liver abscess. The purpose of this case report is to relate an unusual presentation of liver transplantation to show how successive treatment can be an appropriate option in septic patients after liver transplantation. We report on a patient with liver transplantation who developed sepsis due to extended spectrum beta-lactamases and AmpC-producing E. aerogenes. A 39-year-old man had a biliary fistula and then was found to have multiple liver abscesses through abdominal ultrasound and an abdominal computed tomography scan, and carbapenem-sensitive E. aerogenes infection was confirmed. The patient was not successfully treated with conservative treatment consisting of intravenous carbapenems, percutaneous transhepatic cholangial drainage, and biliary stent placement by endoscopic retrograde cholangiopancreatography, so a second liver transplantation followed. Carbapenem-resistant E. aerogenes was detected in bile and blood after a five-week course of carbapenem therapy. The patient developed septic shock and multiple organ dysfunction syndrome. We first report an unusual case of sepsis caused by E. aerogenes after liver transplantation in China. Carbapenem-resistant E. aerogenes finally leads to uncontrolled sepsis with current antibiotics. We hypothesize that the infection developed as a result of biliary fistula and predisposing immunosuppressive agent therapy. Further research is progressing on the aspect of immunomodulation therapy.

Detection of New Delhi Metallo-Beta-Lactamase (Encoded by blaNDM-1 ) in Enterobacter aerogenes in China.

PubMed

Shen, Yong; Xiao, Wei-Qiang; Gong, Jiao-Mei; Pan, Jun; Xu, Qing-Xia

2017-03-01

The increase in bla NDM -1 in Enterobacteriaceae has become a major concern worldwide. In previous study, we investigated clonal dissemination and mechanisms of resistance to carbapenem in China. We carried out retrospective surveillance for bla NDM -1 among carbapenem-resistant enterobacter strains, which were isolated from patients at our hospital by bacterial strains selection, antimicrobial susceptibility testing, species identification, and molecular detection of resistance gene. We found three bla NDM -1 -positive isolates which were identified as Enterobacter aerogenes in clinical patients in China. The bla NDM -1 -positive Enterobacter aerogenes isolates were first found. It is important to mandate prudent usage of antibiotics and implement infection control measures to control the spread of these resistant bla NDM -1 -positive strains. © 2016 Wiley Periodicals, Inc.

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.

PubMed

Brisse, S; Milatovic, D; Fluit, A C; Verhoef, J; Martin, N; Scheuring, S; Köhrer, K; Schmitz, F J

1999-08-01

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.

Isolation of Enterobacter aerogenes carrying blaTEM-1 and blaKPC-3 genes recovered from a hospital Intensive Care Unit.

PubMed

Pulcrano, Giovanna; Pignanelli, Salvatore; Vollaro, Adriana; Esposito, Matilde; Iula, Vita Dora; Roscetto, Emanuela; Soriano, Amata Amy; Catania, Maria Rosaria

2016-06-01

Enterobacter aerogenes has recently emerged as an important hospital pathogen. In this study, we showed the emergence of E. aerogenes isolates carrying the blaKPC gene in patients colonized by carbapenem-resistant Klebsiella pneumoniae strains. Two multiresistant E. aerogenes isolates were recovered from bronchial aspirates of two patients hospitalized in the Intensive Care Unit at the "Santa Maria della Scaletta" Hospital, Imola. The antimicrobial susceptibility test showed the high resistance to carbapenems and double-disk synergy test confirmed the phenotype of KPC and AmpC production. Other investigation revealed that ESBL and blaKPC genes were carried on the conjugative pKpQIL plasmid. This is a relevant report in Italy that describes a nosocomial infection due to the production of KPC beta-lactamases by an E. aerogenes isolate in patients previously colonized by K. pneumoniae carbapenem-resistant. In conclusion, it's necessary a continuous monitoring of multidrug-resistant strains for the detection of any KPC-producing bacteria that could expand the circulation of carbapenem-resistant pathogens. © 2016 APMIS. Published by John Wiley & Sons Ltd.

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

PubMed Central

Brisse, Sylvain; Milatovic, Dana; Fluit, Ad C.; Verhoef, Jan; Martin, Nele; Scheuring, Sybille; Köhrer, Karl; Schmitz, Franz-Josef

1999-01-01

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. PMID:10428935

Partial purification and characterization of a novel histidine decarboxylase from Enterobacter aerogenes DL-1.

PubMed

Zou, Yu; Hu, Wenzhong; Jiang, Aili; Tian, Mixia

2015-08-18

Histidine decarboxylase (HDC) from Enterobacter aerogenes DL-1 was purified in a three-step procedure involving ammonium sulfate precipitation, Sephadex G-100, and DEAE-Sepharose column chromatography. The partially purified enzyme showed a single protein band of 52.4 kD on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The optimum pH for HDC activity was 6.5, and the enzyme was stable between pH 4 and 8. Enterobacter aerogenes HDC had optimal activity at 40°C and retained most of its activity between 4 and 50°C. HDC activity was reduced in the presence of numerous tested compounds. Particularly with SDS, it significantly (p < 0.01) inhibited enzyme activity. Conversely, Ca(2+) and Mn(2+) showed prominent activation effects (p < 0.01) with activity increasing to 117.20% and 123.42%, respectively. The Lineweaver-Burk plot showed that K m and V max values of the enzyme for L-histidine were 0.21 mM and 71.39 µmol/min, respectively. In comparison with most HDCs from other microorganisms and animals, HDC from E. aerogenes DL-1 displayed higher affinity and greater reaction velocity toward L-histidine.

Biotransformation of ferulic acid to 4-vinylguaiacol by Enterobacter soli and E. aerogenes.

PubMed

Hunter, William J; Manter, Daniel K; van der Lelie, Daniel

2012-12-01

We investigated the conversion of ferulic acid to 4-vinylguaiacol (4-VG), vanillin, vanillyl alcohol, and vanillic acid by five Enterobacter strains. These high-value chemicals are usually synthesized by chemical methods but biological synthesis adds market value. Ferulic acid, a relatively inexpensive component of agricultural crops, is plentiful in corn hulls, cereal bran, and sugar-beet pulp. Two Enterobacter strains, E. soli, and E. aerogenes, accumulated 550-600 ppm amounts of 4-VG when grown in media containing 1,000 ppm ferulic acid; no accumulations were observed with the other strains. Decreasing the amount of ferulic acid present in the media increased the conversion efficiency. When ferulic acid was supplied in 500, 250, or 125 ppm amounts E. aerogenes converted ~72 % of the ferulic acid present to 4-VG while E. soli converted ~100 % of the ferulic acid to 4-VG when supplied with 250 or 125 ppm amounts of ferulic acid. Also, lowering the pH improved the conversion efficiency. At pH 5.0 E. aerogenes converted ~84 % and E. soli converted ~100 % of 1,000 ppm ferulic acid to 4-VG. Only small, 1-5 ppm, accumulations of vanillin, vanillyl alcohol, and vanillic acid were observed. E. soli has a putative phenolic acid decarboxylase (PAD) that is 168 amino acids long and is similar to PADs in other enterobacteriales; this protein is likely involved in the bioconversion of ferulic acid to 4-VG. E. soli or E. aerogenes might be useful as a means of biotransforming ferulic acid to 4-VG.

Imipenem Resistance of Enterobacter aerogenes Mediated by Outer Membrane Permeability

PubMed Central

Bornet, Charléric; Davin-Regli, Anne; Bosi, Claude; Pages, Jean-Marie; Bollet, Claude

2000-01-01

Multidrug-resistant Enterobacter aerogenes strains are increasingly isolated in Europe and especially in France. Treatment leads to imipenem resistance, because of a lack of porin. We studied the evolution of resistance in 29 strains isolated from four patients during their clinical course. These strains belonged to the prevalent epidemiological type observed in France in previous studies (C. Bosi, et al., J. Clin. Microbiol. 37:2165–2169, 1999; A. Davin-Regli et al., J. Clin. Microbiol. 34:1474–1480, 1996). They also harbored a TEM-24 extended-spectrum β-lactamase-coding gene. Thirteen strains were susceptible to gentamicin and resistant to imipenem and cefepime. All of the patients showed E. aerogenes strains with this resistance after an imipenem treatment. One patient showed resistance to imipenem after a treatment with cefpirome. Twelve of these 13 strains showed a lack of porin. Cessation of treatment with imipenem for three patients was followed by reversion of susceptibility to this antibiotic and the reappearance of porins, except in one case. For one patient, we observed three times in the same day the coexistence of resistant strains lacking porin and susceptible strains possessing porin. The emergence of multidrug-resistant E. aerogenes strains is very disquieting. In our study, infection by E. aerogenes increased the severity of the patients' illnesses, causing a 100% fatality rate. PMID:10698994

Enterobacter aerogenes ZDY01 Attenuates Choline-Induced Trimethylamine N-Oxide Levels by Remodeling Gut Microbiota in Mice.

PubMed

Qiu, Liang; Yang, Dong; Tao, Xueying; Yu, Jun; Xiong, Hua; Wei, Hua

2017-08-28

Trimethylamine N -oxide (TMAO), which is transformed from trimethylamine (TMA) through hepatic flavin-containing monooxygenases, can promote atherosclerosis. TMA is produced from dietary carnitine, phosphatidylcholine, and choline via the gut microbes. Previous works have shown that some small molecules, such as allicin, resveratrol, and 3,3-dimethyl-1-butanol, are used to reduce circulating TMAO levels. However, the use of bacteria as an effective therapy to reduce TMAO levels has not been reported. In the present study, 82 isolates were screened from healthy Chinese fecal samples on a basal salt medium supplemented with TMA as the sole carbon source. The isolates belonged to the family Enterobacteriaceae, particularly to genera Klebsiella, Escherichia, Cronobacter , and Enterobacter . Serum TMAO and cecal TMA levels were significantly decreased in choline-fed mice treated with Enterobacter aerogenes ZDY01 compared with those in choline-fed mice treated with phosphate-buffered saline. The proportions of Bacteroidales family S24-7 were significantly increased, whereas the proportions of Helicobacteraceae and Prevotellaceae were significantly decreased through the administration of E. aerogenes ZDY01. Results indicated that the use of probiotics to act directly on the TMA in the gut might be an alternative approach to reduce serum TMAO levels and to prevent the development of atherosclerosis and "fish odor syndrome" through the effect of TMA on the gut microbiota.

Effect of nanocomposite packaging containing ZnO on growth of Bacillus subtilis and Enterobacter aerogenes.

PubMed

Esmailzadeh, Hakimeh; Sangpour, Parvaneh; Shahraz, Farzaneh; Hejazi, Jalal; Khaksar, Ramin

2016-01-01

Recent advances in nanotechnology have opened new windows in active food packaging. Nano-sized ZnO is an inexpensive material with potential antimicrobial properties. The aim of the present study is to evaluate the antibacterial effect of low density Polyethylene (LDPE) containing ZnO nanoparticles on Bacillus subtilis and Enterobacter aerogenes. ZnO nanoparticles have been synthesized by facil molten salt method and have been characterized by X-ray diffraction (XRD), and scanning electron microscopy (SEM). Nanocomposite films containing 2 and 4 wt.% ZnO nanoparticles were prepared by melt mixing in a twin-screw extruder. The growth of both microorganisms has decreased in the presence of ZnO containing nanocomposites compared with controls. Nanocomposites with 4 wt.% ZnO nanoparticles had stronger antibacterial effect against both bacteria in comparison with the 2 wt.% ZnO containing nanocomposites. B. subtilis as Gram-positive bacteria were more sensitive to ZnO containing nanocomposite films compared with E. aerogenes as Gram-negative bacteria. There were no significant differences between the migration of Zn ions from 2 and 4 wt.% ZnO containing nanocomposites and the released Zn ions were not significantly increased in both groups after 14 days compared with the first. Regarding the considerable antibacterial effects of ZnO nanoparticles, their application in active food packaging can be a suitable solution for extending the shelf life of food. Copyright © 2015. Published by Elsevier B.V.

Characterization of a novel qepA3 variant in Enterobacter aerogenes.

PubMed

Wang, Dongguo; Huang, Xitian; Chen, Jiayu; Mou, Yonghua; Qi, Yongxiao

2017-04-01

Five isolates harboring qepA were studied by polymerase chain reaction (PCR) amplification and relevant methods. One was determined to be a novel qepA3 from Enterobacter aerogenes, and four involved three qepA1 and one qepA2 determinants from Escherichia coli; the qepA3 changed five amino acids. These results characterized genetic structures A, B, C, D, and E. Copyright © 2016. Published by Elsevier B.V.

Isolation and characterization of a bacteriophage phiEap-2 infecting multidrug resistant Enterobacter aerogenes

PubMed Central

Li, Erna; Wei, Xiao; Ma, Yanyan; Yin, Zhe; Li, Huan; Lin, Weishi; Wang, Xuesong; Li, Chao; Shen, Zhiqiang; Zhao, Ruixiang; Yang, Huiying; Jiang, Aimin; Yang, Wenhui; Yuan, Jing; Zhao, Xiangna

2016-01-01

Enterobacter aerogenes (Enterobacteriaceae) is an important opportunistic pathogen that causes hospital-acquired pneumonia, bacteremia, and urinary tract infections. Recently, multidrug-resistant E. aerogenes have been a public health problem. To develop an effective antimicrobial agent, bacteriophage phiEap-2 was isolated from sewage and its genome was sequenced because of its ability to lyse the multidrug-resistant clinical E. aerogenes strain 3-SP. Morphological observations suggested that the phage belongs to the Siphoviridae family. Comparative genome analysis revealed that phage phiEap-2 is related to the Salmonella phage FSL SP-031 (KC139518). All of the structural gene products (except capsid protein) encoded by phiEap-2 had orthologous gene products in FSL SP-031 and Serratia phage Eta (KC460990). Here, we report the complete genome sequence of phiEap-2 and major findings from the genomic analysis. Knowledge of this phage might be helpful for developing therapeutic strategies against E. aerogenes. PMID:27320081

Isolation and characterization of a bacteriophage phiEap-2 infecting multidrug resistant Enterobacter aerogenes.

PubMed

Li, Erna; Wei, Xiao; Ma, Yanyan; Yin, Zhe; Li, Huan; Lin, Weishi; Wang, Xuesong; Li, Chao; Shen, Zhiqiang; Zhao, Ruixiang; Yang, Huiying; Jiang, Aimin; Yang, Wenhui; Yuan, Jing; Zhao, Xiangna

2016-06-20

Enterobacter aerogenes (Enterobacteriaceae) is an important opportunistic pathogen that causes hospital-acquired pneumonia, bacteremia, and urinary tract infections. Recently, multidrug-resistant E. aerogenes have been a public health problem. To develop an effective antimicrobial agent, bacteriophage phiEap-2 was isolated from sewage and its genome was sequenced because of its ability to lyse the multidrug-resistant clinical E. aerogenes strain 3-SP. Morphological observations suggested that the phage belongs to the Siphoviridae family. Comparative genome analysis revealed that phage phiEap-2 is related to the Salmonella phage FSL SP-031 (KC139518). All of the structural gene products (except capsid protein) encoded by phiEap-2 had orthologous gene products in FSL SP-031 and Serratia phage Eta (KC460990). Here, we report the complete genome sequence of phiEap-2 and major findings from the genomic analysis. Knowledge of this phage might be helpful for developing therapeutic strategies against E. aerogenes.

KPC-2 carbapenemase and DHA-1 AmpC determinants carried on the same plasmid in Enterobacter aerogenes.

PubMed

Kuai, Shougang; Shao, Haifeng; Huang, Lihua; Pei, Hao; Lu, Zhonghua; Wang, Weiping; Liu, Jun

2014-03-01

This study was conducted to analyse the presence of a plasmid-mediated carbapenem resistance mechanism in a clinical Enterobacter aerogenes isolate from a patient from Jiangsu province, People's Republic of China. PCR and sequencing confirmed that the isolate harboured Klebsiella pneumoniae carbapenemase (KPC)-2, DHA-1 and TEM-1 β-lactamase genes. Both the KPC-2 and DHA-1 genes were transferred to Escherichia coli C600 by transconjugation, and Southern blotting confirmed that these two genes were located on the same plasmid, which was of approximately 56 kb in size. The Enterobacter aerogenes isolate was resistant to carbapenems and other tested antimicrobial agents. The Escherichia coli transconjugant showed reduced susceptibility but not resistance to carbapenems and other β-lactams, indicating the presence of another, possibly permeability-related, resistance mechanism in the clinical isolate.

Outbreak of multidrug-resistant acute postoperative endophthalmitis due to Enterobacter aerogenes.

PubMed

Bhat, Shailaja S; Undrakonda, Vivekanand; Mukhopadhyay, Chiranjay; Parmar, Prachi Vikramsinh

2014-04-01

To report the clinical features, management, and outcome of 7 cases of culture-proven multidrug-resistant Enterobacter postoperative endophthalmitis following cataract surgery. Medical records of 7 cases of acute postoperative endophthalmitis after uneventful cataract surgery were reviewed. Details regarding age, gender, visual acuity and clinical features at presentation, microbiological profile, treatment interventions, and visual acuity and clinical features at 1 week, 1 month, and 3 months follow-up were collected. All patients reported decreased visual acuity and pain as presenting symptoms. All patients were resistant to intravitreal antibiotics such as vancomycin (1 mg/0.1 mL) and ceftazidime (2.25 mg/0.1 mL). Culture of aqueous and vitreous sample was positive for Enterobacter aerogenes and sensitive to co-trimoxazole, cefoperazone-sulbactam, imipenem-meropenem, and piperacillin-tazobactem. Two patients with panophthalmitis and no perception of light underwent evisceration. Three patients had visual acuity of ≥6/24 at the final follow-up. Multidrug-resistant Enterobacter acute postoperative endophthalmitis has a poor prognosis if not intercepted early.

Detection of Extended-Spectrum β-Lactamases in Clinical Isolates of Enterobacter cloacae and Enterobacter aerogenes

PubMed Central

Tzelepi, Eva; Giakkoupi, Panagiota; Sofianou, Danai; Loukova, Veneta; Kemeroglou, Anastassia; Tsakris, Athanassios

2000-01-01

The aim of the present study was to investigate the frequency of extended-spectrum β-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 β-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. PMID:10655342

Bioremediation of chromium by novel strains Enterobacter aerogenes T2 and Acinetobacter sp. PD 12 S2.

PubMed

Panda, Jigisha; Sarkar, Priyabrata

2012-06-01

This study had an objective to identify the most potent chromium-resistant bacteria isolated from tannery effluent and apply them for bioremediation of chromium in tannery effluents. Two such strains (previously characterized and identified by us)--Enterobacter aerogenes (NCBI GenBank USA Accession no. GU265554) and Acinetobacter sp. PD 12 (NCBI GenBank USA Accession no. GU084179)--showed powerful chromium resistivity and bioremediation capabilities among many stains isolated from tannery waste. Parameters such as pH, concentration of hexavalent chromium or Cr (VI), and inoculum volume were varied to observe optimum bioconversion and bioaccumulation of Cr (VI) when the said strains were grown in M9 minimal salt media. E. aerogenes was used to remediate chromium from tannery effluents in a laboratory level experiment. Observation by Scanning Electron Microscope and chromium peak in Energy Dispersive X-ray Spectroscopic microanalysis revealed that E. aerogenes helped remediate a moderate amount of Cr (VI) (8-16 mg L(-1)) over a wide range of pH values at 35-37°C (within 26.05 h). High inoculum percentage of Acinetobacter sp. PD 12 also enabled bioremediation of 8-16 mg L(-1) of Cr (VI) over a wide range of temperature (25-37°C), mainly at pH 7 (within 63.28 h). The experiment with real tannery effluent gave very encouraging results. The strain E. aerogenes can be used in bioremediation of Cr (VI) since it could work in actual environmental conditions with extraordinarily high capacity.

Most Enterobacter aerogenes Strains in France Belong to a Prevalent Clone

PubMed Central

Bosi, Claude; Davin-Regli, Anne; Bornet, Charleric; Mallea, Monique; Pages, Jean-Marie; Bollet, Claude

1999-01-01

The aim of this study was to determine the distribution in France of the Enterobacter aerogenes prevalent clone isolated in the hospitals of the Marseille area (A. Davin-Regli, D. Monnet, P. Saux, C. Bosi, R. Charrel, A. Barthelemy, and C. Bollet, J. Clin. Microbiol. 34:1474–1480, 1996). A total of 123 E. aerogenes isolates were collected from 23 hospital laboratories and analyzed by random amplification of polymorphic DNA and enterobacterial repetitive intergenic consensus-PCR to determine their epidemiological relatedness. Molecular typing revealed that 21 of the 23 laboratories had isolated this prevalent clone harboring the plasmid encoding for extended-spectrum β-lactamase of the TEM-24 type. Most isolates were susceptible only to imipenem and gentamicin. Their dissemination seems to be clonal and was probably the result of the general use of broad-spectrum cephalosporins and quinolones. Four isolates showed an alteration of their outer membrane proteins, causing decrease of susceptibility to third-generation cephalosporins and imipenem and leading to the critical situation of having no alternative therapeutic. The large dissemination of the E. aerogenes prevalent clone probably results from its good adaptation to the antibiotics administered in France and the hospital environment, particularly in intensive care units. PMID:10364580

Pathway engineering of Enterobacter aerogenes to improve acetoin production by reducing by-products formation.

PubMed

Jang, Ji-Woong; Jung, Hwi-Min; Im, Dae-Kyun; Jung, Moo-Young; Oh, Min-Kyu

2017-11-01

Enterobacter aerogenes was metabolically engineered for acetoin production. To remove the pathway enzymes that catalyzed the formation of by-products, the three genes encoding a lactate dehydrogenase (ldhA) and two 2,3-butanediol dehydrogenases (budC, and dhaD), respectively, were deleted from the genome. The acetoin production was higher under highly aerobic conditions. However, an extracellular glucose oxidative pathway in E. aerogenes was activated under the aerobic conditions, resulting in the accumulation of 2-ketogluconate. To decrease the accumulation of this by-product, the gene encoding a glucose dehydrogenase (gcd) was also deleted. The resulting strain did not produce 2-ketogluconate but produced significant amounts of acetoin, with concentration reaching 71.7g/L with 2.87g/L/h productivity in fed-batch fermentation. This result demonstrated the importance of blocking the glucose oxidative pathway under highly aerobic conditions for acetoin production using E. aerogenes. Copyright © 2017 Elsevier Inc. All rights reserved.

Occurrence of efflux mechanism and cephalosporinase variant in a population of Enterobacter aerogenes and Klebsiella pneumoniae isolates producing extended-spectrum beta-lactamases.

PubMed

Tran, Que-Tien; Dupont, Myrielle; Lavigne, Jean-Philippe; Chevalier, Jacqueline; Pagès, Jean-Marie; Sotto, Albert; Davin-Regli, Anne

2009-04-01

We investigated the occurrence of multidrug resistance in 44 Enterobacter aerogenes and Klebsiella pneumoniae clinical isolates. Efflux was involved in resistance in E. aerogenes isolates more frequently than in K. pneumoniae isolates (100 versus 38% of isolates) and was associated with the expression of phenylalanine arginine beta-naphthylamide-susceptible active efflux. AcrA-TolC overproduction in E. aerogenes isolates was noted. An analysis of four E. aerogenes isolates for which cefepime MICs were high revealed no modification in porin expression but a new specific mutation in the AmpC beta-lactamase.

The AcrAB-TolC pump is involved in macrolide resistance but not in telithromycin efflux in Enterobacter aerogenes and Escherichia coli.

PubMed

Chollet, Renaud; Chevalier, Jacqueline; Bryskier, André; Pagès, Jean-Marie

2004-09-01

The role of the AcrAB-TolC pump in macrolide and ketolide susceptibility in Escherichia coli and Enterobacter aerogenes was studied. Efflux pump inhibitor restored erythromycin, clarithromycin, and telithromycin susceptibilities to multidrug-resistant isolates. No modification of telithromycin accumulation was detected in E. aerogenes acrAB or tolC derivatives compared to that in the parental strain. Two independent efflux pumps, inhibited by phenylalanine arginine beta-naphthylamide, expel macrolides and telithromycin in E. aerogenes.

Cloning and characterization of the ddc homolog encoding L-2,4-diaminobutyrate decarboxylase in Enterobacter aerogenes.

PubMed

Yamamoto, S; Mutoh, N; Tsuzuki, D; Ikai, H; Nakao, H; Shinoda, S; Narimatsu, S; Miyoshi, S I

2000-05-01

L-2,4-diaminobutyrate decarboxylase (DABA DC) catalyzes the formation of 1,3-diaminopropane (DAP) from DABA. In the present study, the ddc gene encoding DABA DC from Enterobacter aerogenes ATCC 13048 was cloned and characterized. Determination of the nucleotide sequence revealed an open reading frame of 1470 bp encoding a 53659-Da protein of 490 amino acids, whose deduced NH2-terminal sequence was identical to that of purified DABA DC from E. aerogenes. The deduced amino acid sequence was highly similar to those of Acinetobacter baumannii and Haemophilus influenzae DABA DCs encoded by the ddc genes. The lysine-307 of the E. aerogenes DABA DC was identified as the pyridoxal 5'-phosphate binding residue by site-directed mutagenesis. Furthermore, PCR analysis revealed the distribution of E. aerogenes ddc homologs in some other species of Enterobacteriaceae. Such a relatively wide occurrence of the ddc homologs implies biological significance of DABA DC and its product DAP.

Development of Enterobacter aerogenes fuel cells: from in situ biohydrogen oxidization to direct electroactive biofilm.

PubMed

Zhuang, Li; Zhou, Shungui; Yuan, Yong; Liu, Tinglin; Wu, Zhifeng; Cheng, Jiong

2011-01-01

This study described an Enterobacter aerogenes-catalyzed microbial fuel cell (MFC) with a carbon-based anode that exhibited a maximum power density of 2.51 W/m(3) in the absence of artificial electron mediators. The MFC was started up rapidly, within hours, and the current generation in the early stage was demonstrated to result from in situ oxidation of biohydrogen produced by E. aerogenes during glucose fermentation. Over periodic replacement of substrate, both planktonic biomass in the culture liquid and hydrogen productivity decreased, while increased power density and coulombic efficiency and decreased internal resistance were unexpectedly observed. Using scanning electron microscopy and cyclic voltammetry, it was found that the enhanced MFC performance was associated with the development of electroactive biofilm on the anodic surface, proposed to involve an acclimation and selection process of E. aerogenes cells under electrochemical tension. The significant advantage of rapid start-up and the ability to develop an electroactive biofilm identifies E. aerogenes as a suitable biocatalyst for MFC applications. Copyright © 2010 Elsevier Ltd. All rights reserved.

Biological Conversion of Glycerol to Ethanol by Enterobacter aerogenes

NASA Astrophysics Data System (ADS)

Nwachukwu, Raymond E. S.

In a search to turn the economically and environmentally non-valuable "waste" streams of biodiesel production into a profitable byproduct, a mutant strain of Enterobacter aerogenes ATCC 13048 was developed by six-tube subculturing technique. This technique is based on the principle of adaptive evolution, and involved subculturing the bacterium in a tryptic soy broth without dextrose (TSB) containing specific glycerol and ethanol concentration for six consecutive times. Then, the six consecutive subculturing was repeated in a fresh TSB of higher glycerol and ethanol concentrations. A new mutant strain, E. aerogenes S012, which could withstand a combination of 200 g/l glycerol and 30 g/l ethanol concentrations, was developed. The wild and mutant strains were used for the fermentation of pure (P-) and recovered (R-) glycerol. Taguchi and full factorial methods of design of experiments were used to screen and optimize the important process factors that influence the microbial production of ethanol. A statistically sound regression model was used to establish the mathematical relationship between the process variables and ethanol production. Temperature of 38°C, agitation speed of 200 rpm, pH of 6.3-6.6, and microaerobic condition were the optimum process conditions. Different pretreatment methods to recover glycerol from the crude glycerol and the subsequent fermentation method showed that direct acidification using 85% H3PO4 was the best. The R-glycerol contained 51% pure glycerol and 21% methanol. The wild strain, E. aerogenes ATCC 13048, produced only 12 g/l and 12.8 g/l ethanol from 20 g/l P- and R-glycerol respectively, and could not utilize higher glycerol concentrations. The mutant, E. aerogenes S012, produced ethanol amount and yield of 43 g/l and 1.12 mol/mol-glycerol from P-glycerol, respectively within 96 h. It also produced ethanol amount and yield of 26.8 g/l and 1.07 mol/mol-glycerol, respectively, from R-glycerol within the same duration. In a

Isolation and characterization of a bacteriophage F20 virulent to Enterobacter aerogenes.

PubMed

Mishra, Charitra Kumar; Choi, Tae Jin; Kang, Sun Chul

2012-10-01

An aquatic phage, designated F20, was characterized and its physico-chemical characteristics studied. F20 was specifically virulent to only two strains of Enterobacter aerogenes (ATCC 13048 and the multi-drug-resistant strain K113) among other species tested (n = 15). It was classified in the family Siphoviridae of T1-like viruses and contained a linear dsDNA genome estimated to be 51.5 kbp enclosed by an isometric capsid of 50±2 nm in diameter and a tail of 150±3 nm in length. F20 was able to survive in a broad pH range between 4 and 11, showed potential for future animal trials using oral solution and resisted chloroform and ethanol. It exhibited remarkable stability between room temperature and 70 °C for up to 150 min, and even up to 6 months at room temperature. Knowledge of this phage belonging to the widespread T1-like viruses might be helpful for adopting therapeutic strategies against E. aerogenes.

Deletion of lactate dehydrogenase in Enterobacter aerogenes to enhance 2,3-butanediol production.

PubMed

Jung, Moo-Young; Ng, Chiam Yu; Song, Hyohak; Lee, Jinwon; Oh, Min-Kyu

2012-07-01

2,3-Butanediol is an important bio-based chemical product, because it can be converted into several C4 industrial chemicals. In this study, a lactate dehydrogenase-deleted mutant was constructed to improve 2,3-butanediol productivity in Enterobacter aerogenes. To delete the gene encoding lactate dehydrogenase, λ Red recombination method was successfully adapted for E. aerogenes. The resulting strain produced a very small amount of lactate and 16.7% more 2,3-butanediol than that of the wild-type strain in batch fermentation. The mutant and its parental strain were then cultured with six different carbon sources, and the mutant showed higher carbon source consumption and microbial growth rates in all media. The 2,3-butanediol titer reached 69.5 g/l in 54 h during fed-batch fermentation with the mutant,which was 27.4% higher than that with the parental strain.With further optimization of the medium and aeration conditions,118.05 g/l 2,3-butanediol was produced in 54 h during fed-batch fermentation with the mutant. This is by far the highest titer of 2,3-butanediol with E. aerogenes achieved by metabolic pathway engineering.

National Epidemiologic Surveys of Enterobacter aerogenes in Belgian Hospitals from 1996 to 1998

PubMed Central

De Gheldre, Y.; Struelens, M. J.; Glupczynski, Y.; De Mol, P.; Maes, N.; Nonhoff, C.; Chetoui, H.; Sion, C.; Ronveaux, O.; Vaneechoutte, M.

2001-01-01

Two national surveys were conducted to describe the incidence and prevalence of Enterobacter aerogenes in 21 Belgian hospitals in 1996 and 1997 and to characterize the genotypic diversity and the antimicrobial resistance profiles of clinical strains of E. aerogenes isolated from hospitalized patients in Belgium in 1997 and 1998. Twenty-nine hospitals collected 10 isolates of E. aerogenes, which were typed by arbitrarily primed PCR (AP-PCR) using two primers and pulsed-field gel electrophoresis. MICs of 10 antimicrobial agents were determined by the agar dilution method. Beta-lactamases were detected by the double-disk diffusion test and characterized by isoelectric point. The median incidence of E. aerogenes colonization or infection increased from 3.3 per 1,000 admissions in 1996 to 4.2 per 1000 admissions in the first half of 1997 (P < 0.01). E. aerogenes strains (n = 260) clustered in 25 AP-PCR types. Two major types, BE1 and BE2, included 36 and 38% of strains and were found in 21 and 25 hospitals, respectively. The BE1 type was indistinguishable from a previously described epidemic strain in France. Half of the strains produced an extended-spectrum beta-lactamase, either TEM-24 (in 86% of the strains) or TEM-3 (in 14% of the strains). Over 75% of the isolates were resistant to ceftazidime, piperacillin-tazobactam, and ciprofloxacin. Over 90% of the strains were susceptible to cefepime, carbapenems, and aminoglycosides. In conclusion, these data suggest a nationwide dissemination of two epidemic multiresistant E. aerogenes strains in Belgian hospitals. TEM-24 beta-lactamase was frequently harbored by one of these epidemic strains, which appeared to be genotypically related to a TEM-24-producing epidemic strain from France, suggesting international dissemination. PMID:11230400

Enhanced dark hydrogen fermentation by addition of ferric oxide nanoparticles using Enterobacter aerogenes.

PubMed

Lin, Richen; Cheng, Jun; Ding, Lingkan; Song, Wenlu; Liu, Min; Zhou, Junhu; Cen, Kefa

2016-05-01

Ferric oxide nanoparticles (FONPs) were used to facilitate dark hydrogen fermentation using Enterobacter aerogenes. The hydrogen yield of glucose increased from 164.5±2.29 to 192.4±1.14mL/g when FONPs concentration increased from 0 to 200mg/L. SEM images of E. aerogenes demonstrated the existence of bacterial nanowire among cells, suggesting FONPs served as electron conduits to enhance electron transfer. TEM showed cellular internalization of FONPs, indicating hydrogenase synthesis and activity was potentially promoted due to the released iron element. When further increasing FONPs concentration to 400mg/L, the hydrogen yield of glucose decreased to 147.2±2.54mL/g. Soluble metabolic products revealed FONPs enhanced acetate pathway of hydrogen production, but weakened ethanol pathway. This shift of metabolic pathways allowed more nicotinamide adenine dinucleotide for reducing proton to hydrogen. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of Sodium on the Transport and Utilization of Citric Acid by Aerobacter (Enterobacter) aerogenes

PubMed Central

Wilkerson, L. S.; Eagon, R. G.

1974-01-01

Sodium inhibited citrate uptake by two of the four strains of Aerobacter (Enterobacter) aerogenes used in these studies, had no effect on one strain, and stimulated citrate uptake by one strain. Two of the four strains grew well anaerobically on citrate in the presence of Na+, one grew poorly, and one grew not at all either in the presence or absence of Na+. Na+ stimulated the aerobic growth of one strain on citrate, increased the total growth but not the rate of growth of one strain, and prolonged the lag phase but not the rate of growth or total growth of two strains. The experimental data reported herein, therefore, indicate that there are appreciable physiological differences among strains of A. aerogenes. PMID:4418533

Draft Genome Assemblies of Enterobacter aerogenes CDC 6003-71, Enterobacter cloacae CDC 442-68, and Pantoea agglomerans UA 0804-01.

PubMed

Minogue, T D; Daligault, H E; Davenport, K W; Bishop-Lilly, K A; Bruce, D C; Chain, P S; Coyne, S R; Chertkov, O; Freitas, T; Frey, K G; Jaissle, J; Koroleva, G I; Ladner, J T; Palacios, G F; Redden, C L; Xu, Y; Johnson, S L

2014-10-23

The Enterobacteriaceae are environmental and enteric microbes. We sequenced the genomes of two Enterobacter reference strains, E. aerogenes CDC 6003-71 and E. cloacae CDC 442-68, as well as one near neighbor used as an exclusionary reference for diagnostics, Pantoea agglomerans CDC UA0804-01. The genome sizes range from 4.72 to 5.55 Mbp and have G+C contents from 54.6 to 55.1%. Copyright © 2014 Minogue et al.

Molecular Epidemiological Study of Nosocomial Enterobacter aerogenes Isolates in a Belgian Hospital

PubMed Central

Jalaluddin, Sheikh; Devaster, Jeanne-Marie; Scheen, Robert; Gerard, Michele; Butzler, Jean-Paul

1998-01-01

In 1995, the rate of isolation of Enterobacter aerogenes in the Saint-Pierre University Hospital in Brussels, Belgium, was higher than that in the preceding years. A total of 45 nosocomial E. aerogenes strains were collected from 33 patients of different units during that year, and they were isolated from 19 respiratory specimens, 13 pus specimens, 7 blood specimens, 4 urinary specimens, 1 catheter specimen, and 1 heparin vial. The strains were analyzed to determine their epidemiological relatedness and were characterized by their antibiotic resistance pattern determination, plasmid profiling, and genomic fingerprinting by macrorestriction analysis with pulsed-field gel electrophoresis (PFGE). The majority of the strains (82%) were multiply resistant to different commonly used antibiotics. Two major plasmid profiles were found: most strains (64%) harbored two plasmids of different sizes, whereas the others (20%) contained a single plasmid. PFGE with SpeI and/or XbaI restriction enzymes revealed that a single clone (80%) was responsible for causing infections or colonizations throughout the year, and this result was concordant with those obtained by plasmid profiling, with slight variations. By comparing the results of these three methods, PFGE and plasmid profiling were found to be the techniques best suited for investigating the epidemiological relatedness of E. aerogenes strains, and they are therefore proposed as useful tools for the investigation of nosocomial outbreaks caused by this organism. PMID:9650923

Draft Genome Sequences of blaKPC-Containing Enterobacter aerogenes, Citrobacter freundii, and Citrobacter koseri Strains

PubMed Central

Hazen, Tracy H.; Mettus, Roberta T.; McElheny, Christi L.; Bowler, Sarah L.

2018-01-01

ABSTRACT We report here the draft genome sequences of four blaKPC-containing bacteria identified as Klebsiella aerogenes, Citrobacter freundii, and Citrobacter koseri. Additionally, we report the draft genome sequence of a K. aerogenes strain that did not contain a blaKPC gene but was isolated from the patient who had the blaKPC-2-containing K. aerogenes strain. PMID:29472325

Engineered Enterobacter aerogenes for efficient utilization of sugarcane molasses in 2,3-butanediol production.

PubMed

Jung, Moo-Young; Park, Bu-Soo; Lee, Jinwon; Oh, Min-Kyu

2013-07-01

Sugarcane molasses is considered to be a good carbon source for biorefinery due to its high sugar content and low price. Sucrose occupies more than half of the sugar in the molasses. Enterobacter aerogenes is a good host strain for 2,3-butanediol production, but its utilization of sucrose is not very efficient. To improve sucrose utilization in E. aerogenes, a sucrose regulator (ScrR) was disrupted from the genomic DNA. The deletion mutation increased the sucrose consumption rate significantly when sucrose or sugarcane molasses was used as a carbon source. The 2,3-butanediol production from sugarcane molasses by the mutant was enhanced by 60% in batch fermentation compared to that by the wild type strain. In fed-batch fermentation, 98.69 g/L of 2,3-butanediol production was achieved at 36 h. Copyright © 2013 Elsevier Ltd. All rights reserved.

Purification and antibiofilm activity of AHL-lactonase from endophytic Enterobacter aerogenes VT66.

PubMed

Rajesh, P S; Rai, V Ravishankar

2015-11-01

The opportunistic pathogen Pseudomonas aeruginosa uses biofilm lifestyle to resist antibiotic treatment. In our study, endophytic bacterium Enterobacter aerogenes VT66 quenched the N-acyl homoserine lactone (AHL) molecules produced by P. aeruginosa PAO1. The quorum quenching activity was attributed to the presence of AHL-lactonase. The AHL-lactonase was purified using column chromatography and purified AHL-lactonase was applied for the control of biofilm formation in P. aeruginosa PAO1. The results showed that purified AHL-lactonase obtained with a molecular weight about 30kDa was able to inhibit more than 70% of biofilm in P. aeruginosa PAO1 (P<0.001). Antibiofilm activity of AHL-lactonase was correlated well with results from staining technique used to determine inhibition of biomass and viable cell activity. Therefore, results unambiguously confirm that the AHL-lactonase from E. aerogenes VT66 could be used as antibiofilm therapeutics in P. aeruginosa associated biomedical applications. Copyright © 2015 Elsevier B.V. All rights reserved.

Draft Genome Sequences of blaKPC-Containing Enterobacter aerogenes, Citrobacter freundii, and Citrobacter koseri Strains.

PubMed

Hazen, Tracy H; Mettus, Roberta T; McElheny, Christi L; Bowler, Sarah L; Doi, Yohei; Rasko, David A

2018-02-22

We report here the draft genome sequences of four bla KPC -containing bacteria identified as Klebsiella aerogenes , Citrobacter freundii , and Citrobacter koseri Additionally, we report the draft genome sequence of a K. aerogenes strain that did not contain a bla KPC gene but was isolated from the patient who had the bla KPC-2 -containing K. aerogenes strain. Copyright © 2018 Hazen et al.

Establishment of a Molecular Serotyping Scheme and a Multiplexed Luminex-Based Array for Enterobacter aerogenes

PubMed Central

Guo, Xi; Wang, Min; Wang, Lu; Wang, Yao; Chen, Tingting; Wu, Pan; Chen, Min; Liu, Bin; Feng, Lu

2018-01-01

Serotyping based on surface polysaccharide antigens is important for the clinical detection and epidemiological surveillance of pathogens. Polysaccharide gene clusters (PSgcs) are typically responsible for the diversity of bacterial surface polysaccharides. Through whole-genome sequencing and analysis, eight putative PSgc types were identified in 23 Enterobacter aerogenes strains from several geographic areas, allowing us to present the first molecular serotyping system for E. aerogenes. A conventional antigenic scheme was also established and correlated well with the molecular serotyping system that was based on PSgc genetic variation, indicating that PSgc-based molecular typing and immunological serology provide equally valid results. Further, a multiplex Luminex-based array was developed, and a double-blind test was conducted with 97 clinical specimens from Shanghai, China, to validate our array. The results of these analyses indicated that strains containing PSgc4 and PSgc7 comprised the predominant groups. We then examined 86 publicly available E. aerogenes strain genomes and identified an additional seven novel PSgc types, with PSgc10 being the most abundant type. In total, our study identified 15 PSgc types in E. aerogenes, providing the basis for a molecular serotyping scheme. From these results, differing epidemic patterns were identified between strains that were predominant in different regions. Our study highlights the feasibility and reliability of a serotyping system based on PSgc diversity, and for the first time, presents a molecular serotyping system, as well as an antigenic scheme for E. aerogenes, providing the basis for molecular diagnostics and epidemiological surveillance of this important emerging pathogen. PMID:29616012

Establishment of a Molecular Serotyping Scheme and a Multiplexed Luminex-Based Array for Enterobacter aerogenes.

PubMed

Guo, Xi; Wang, Min; Wang, Lu; Wang, Yao; Chen, Tingting; Wu, Pan; Chen, Min; Liu, Bin; Feng, Lu

2018-01-01

Serotyping based on surface polysaccharide antigens is important for the clinical detection and epidemiological surveillance of pathogens. Polysaccharide gene clusters (PSgcs) are typically responsible for the diversity of bacterial surface polysaccharides. Through whole-genome sequencing and analysis, eight putative PSgc types were identified in 23 Enterobacter aerogenes strains from several geographic areas, allowing us to present the first molecular serotyping system for E. aerogenes . A conventional antigenic scheme was also established and correlated well with the molecular serotyping system that was based on PSgc genetic variation, indicating that PSgc-based molecular typing and immunological serology provide equally valid results. Further, a multiplex Luminex-based array was developed, and a double-blind test was conducted with 97 clinical specimens from Shanghai, China, to validate our array. The results of these analyses indicated that strains containing PSgc4 and PSgc7 comprised the predominant groups. We then examined 86 publicly available E. aerogenes strain genomes and identified an additional seven novel PSgc types, with PSgc10 being the most abundant type. In total, our study identified 15 PSgc types in E. aerogenes , providing the basis for a molecular serotyping scheme. From these results, differing epidemic patterns were identified between strains that were predominant in different regions. Our study highlights the feasibility and reliability of a serotyping system based on PSgc diversity, and for the first time, presents a molecular serotyping system, as well as an antigenic scheme for E. aerogenes , providing the basis for molecular diagnostics and epidemiological surveillance of this important emerging pathogen.

An efficient ribitol-specific dehydrogenase from Enterobacter aerogenes.

PubMed

Singh, Ranjitha; Singh, Raushan; Kim, In-Won; Sigdel, Sujan; Kalia, Vipin C; Kang, Yun Chan; Lee, Jung-Kul

2015-05-01

An NAD(+)-dependent ribitol dehydrogenase from Enterobacter aerogenes KCTC 2190 (EaRDH) was cloned and successfully expressed in Escherichia coli. The complete 729-bp gene was amplified, cloned, expressed, and subsequently purified in an active soluble form using nickel affinity chromatography. The enzyme had an optimal pH and temperature of 11.0 and 45°C, respectively. Among various polyols, EaRDH exhibited activity only toward ribitol, with Km, Vmax, and kcat/Km values of 10.3mM, 185Umg(-1), and 30.9s(-1)mM(-1), respectively. The enzyme showed strong preference for NAD(+) and displayed no detectable activity with NADP(+). Homology modeling and sequence analysis of EaRDH, along with its biochemical properties, confirmed that EaRDH belongs to the family of NAD(+)-dependent ribitol dehydrogenases, a member of short-chain dehydrogenase/reductase (SCOR) family. EaRDH showed the highest activity and unique substrate specificity among all known RDHs. Homology modeling and docking analysis shed light on the molecular basis of its unusually high activity and substrate specificity. Copyright © 2015 Elsevier Inc. All rights reserved.

Clonal spread and accumulation of β-lactam resistance determinants in Enterobacter aerogenes and Enterobacter cloacae complex isolates from infection and colonization in patients at a public hospital in Recife, Pernambuco, Brazil.

PubMed

Cabral, Adriane Borges; Maciel, Maria Amélia Vieira; Barros, Josineide Ferreira; Antunes, Marcelo Maranhão; Barbosa de Castro, Célia Maria Machado; Lopes, Ana Catarina Souza

2017-01-01

Enterobacter aerogenes and Enterobacter cloacae complex are the two species of this genus most involved in healthcare-associated infections that are ESBL and carbapenemase producers. This study characterized, phenotypically and genotypically, 51 isolates of E. aerogenes and E. cloacae complex originating from infection or colonization in patients admitted to a public hospital in Recife, Pernambuco, Brazil, by antimicrobial susceptibility profile, analysis of β-lactamase genes (blaTEM, blaSHV, blaCTX-M, blaKPC, blaVIM, blaIMP and blaSPM), PCR and DNA sequencing, plasmid profile and ERIC-PCR. In both species, the genes blaTEM, blaCTX-M and blaKPC were detected. The DNA sequencing confirmed the variants blaTEM-1, blaCTX-M-15 and blaKPC-2 in isolates. More than one gene conferring resistance in the isolates, including the detection of the three previously cited genes in strains isolated from infection sites, was observed. The detection of blaCTX-M was more frequent in isolates from infection sites than from colonization. The gene blaKPC predominated in E. cloacae complex isolates obtained from infections; however, in E. aerogenes isolates, it predominated in samples obtained from colonization. A clonal relationship among all of E. aerogenes isolates was detected by ERIC-PCR. The majority of E. cloacae complex isolates presented the same ERIC-PCR pattern. Despite the clonal relation presented by the isolates using ERIC-PCR, different plasmid and resistance profiles and several resistance genes were observed. The clonal dissemination and the accumulation of β-lactam resistance determinants presented by the isolates demonstrated the ability of E. aerogenes and E. cloacae complex, obtained from colonization and infection, to acquire and maintain different resistance genes.

Biodegradation of 2-methylquinoline by Enterobacter aerogenes TJ-D isolated from activated sludge.

PubMed

Wang, Lin; Li, Yongmei; Duan, Jingyuan

2013-07-01

Bacterial strain Enterobacter aerogenes TJ-D capable of utilizing 2-methylquinoline as the sole carbon and energy source was isolated from acclimated activated sludge under denitrifying conditions. The ability to degrade 2-methylquinoline by E. aerogenes TJ-D was investigated under denitrifying conditions. Under optimal conditions of temperature (35 degrees C) and initial pH 7, 2-methylquinoline of 100 mg/L was degraded within 176 hr. The degradation of 2-methylquinoline by E. aerogenes TJ-D could be well described by the Haldane model (R2 > 0.91). During the degradation period of 2-methylquinoline (initial concentration 100 mg/L), nitrate was almost completely consumed (the removal efficiency was 98.5%), while nitrite remained at low concentration (< 0.62 mg/L) during the whole denitrification period. 1,2,3,4-Tetrahydro-2-methylquinoline, 4-ethyl-benzenamine, N-butyl-benzenamine, N-ethyl-benzenamine and 2,6-diethyl-benzenamine were metabolites produced during the degradation. The degradation pathway of 2-methylquinoline by E. aerogenes TJ-D was proposed. 2-Methylquinoline is initially hydroxylated at C-4 to form 2-methyl-4-hydroxy-quinoline, and then forms 2-methyl-4-quinolinol as a result of tautomerism. Hydrogenation of the heterocyclic ring at positions 2 and 3 produces 2,3-dihydro-2-methyl-4-quinolinol. The carbon-carbon bond at position 2 and 3 in the heterocyclic ring may cleave and form 2-ethyl-N-ethyl-benzenamine. Tautomerism may result in the formation of 2,6-diethyl-benzenamine and N-butyl-benzenamine. 4-Ethyl-benzenamine and N-ethyl-benzenamine were produced as a result of losing one ethyl group from the above molecules.

The purification, crystallization and preliminary diffraction of a glycerophosphodiesterase from Enterobacter aerogenes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jackson, Colin J.; Carr, Paul D.; Kim, Hye-Kyung

2006-07-01

The metallo-glycerophosphodiesterase from E. aerogenes (GpdQ) has been cloned, expressed in E. coli and purified. Initial screening of crystallization conditions for this enzyme resulted in the identification of needles from one condition in a sodium malonate grid screen. Removal of the metals from the enzyme and subsequent optimization of these conditions led to crystals. The metallo-glycerophosphodiesterase from Enterobacter aerogenes (GpdQ) has been cloned, expressed in Escherichia coli and purified. Initial screening of crystallization conditions for this enzyme resulted in the identification of needles from one condition in a sodium malonate grid screen. Removal of the metals from the enzyme andmore » subsequent optimization of these conditions led to crystals that diffracted to 2.9 Å and belonged to space group P2{sub 1}3, with unit-cell parameter a = 164.1 Å. Self-rotation function analysis and V{sub M} calculations indicated that the asymmetric unit contains two copies of the monomeric enzyme, corresponding to a solvent content of 79%. It is intended to determine the structure of this protein utilizing SAD phasing from transition metals or molecular replacement.« less

Porin Deficiency in Carbapenem-Resistant Enterobacter aerogenes Strains.

PubMed

Hao, Min; Ye, Meiping; Shen, Zhen; Hu, Fupin; Yang, Yang; Wu, Shi; Xu, Xiaogang; Zhu, Sihui; Qin, Xiaohua; Wang, Minggui

2018-03-13

The more frequent reports of carbapenem-resistant Enterobacteriaceae have raised the alarm for public health. Apart from the production of carbapenemases, deficiency (decreased or loss of expression) of outer membrane proteins (OMPs) has been proposed as a potentially important mechanism of carbapenem resistance. The aim of the present study was to evaluate the contribution of the major OMPs to carbapenem resistance in Enterobacter aerogenes (CREA) isolates and also investigate the role of small RNAs (sRNAs) in inducing porin-associated permeability defects. The differential expression of OMPs was analyzed in four clinical CREA isolates. omp35 and omp36 genes were further investigated by whole-genome sequencing, induction of meropenem resistance, sRNA overexpression, OMP complementation assays, and reverse transcription-quantitative PCR. All four isolates examined were deficient in omp35 and omp36. Functional restoration of these two genes confirmed their contribution to carbapenem resistance. The meropenem induction assay further revealed that porin deficiency plays a role in carbapenem resistance under antibiotic selection pressure. Single-point mutations in omp36 leading to premature stop codons were detected in two of the isolates. Elevated expression levels of the sRNAs micF and micC were detected in the other two porin-deficient isolates, which were predicted to be potential porin regulators from whole-genome sequencing. Overexpression of micF and micC downregulated the expression of Omp35 and Omp36, respectively. Porin deficiency plays an important role in carbapenem resistance among clinical E. aerogenes isolates under regulation of the sRNAs micC and micF. Furthermore, overexpression of micC and micF had a minor to no impact on carbapenem minimum inhibitory concentrations, and thus, the regulatory mechanism is likely to be complex.

An adaptive response of Enterobacter aerogenes to imipenem: regulation of porin balance in clinical isolates.

PubMed

Lavigne, Jean-Philippe; Sotto, Albert; Nicolas-Chanoine, Marie-Hélène; Bouziges, Nicole; Pagès, Jean-Marie; Davin-Regli, Anne

2013-02-01

Imipenem (IPM) is a carbapenem antibiotic frequently used in severe hospital infections. Several reports have mentioned the emergence of resistant isolates exhibiting membrane modifications. A study was conducted between September 2005 and August 2007 to survey infections due to Enterobacter aerogenes in patients hospitalised in a French university hospital. Resistant E. aerogenes clinical isolates obtained from patients treated with IPM and collected during the 3 months following initiation of treatment were phenotypically and molecularly characterised for β-lactamases, efflux pumps activity and outer membrane proteins. Among the 339 patients infected with E. aerogenes during the study period, 41 isolates (12.1%) were resistant to extended-spectrum cephalosporins and 17 patients (5.0%) were treated with IPM. The isolates from these 17 patients presented TEM-24 and basal efflux expression. Following IPM treatment, an IPM-intermediate-susceptible (IPM-I) isolate emerged in 11 patients and an IPM-resistant (IPM-R) isolate in 6 patients. A change in the porin balance (Omp35/Omp36) was observed in IPM-I isolates exhibiting ertapenem resistance. Finally, a porin deficiency (Omp35 and Omp36 absence) was detected in IPM-R isolates associated with efflux pump expression. This study indicates that the alteration in porin expression, including the shift of porin expression and lack of porins, contribute to the E. aerogenes adaptive response to IPM treatment. Copyright © 2012 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

Extended-Spectrum β-lactamase (ESBL) producing Enterobacter aerogenes phenotypically misidentified as Klebsiella pneumoniae or K. terrigena

PubMed Central

Claeys, Geert; De Baere, Thierry; Wauters, Georges; Vandecandelaere, Patricia; Verschraegen, Gerda; Muylaert, An; Vaneechoutte, Mario

2004-01-01

Background Enterobacter aerogenes and Klebsiella pneumoniae are common isolates in clinical microbiology and important as producers of extended spectrum β-lactamases (ESBL). The discrimination between both species, which is routinely based on biochemical characteristics, is generally accepted to be straightforward. Here we report that genotypically unrelated strains of E. aerogenes can be misidentified as K. pneumoniae by routine laboratories using standard biochemical identification and using identification automates. Results Ten clinical isolates, identified as K. pneumoniae or K. terrigena with the routinely used biochemical tests and with API-20E, were identified as E. aerogenes by tDNA-PCR – an identification that was confirmed by 16S rRNA gene sequencing for five of these isolates. Misidentification also occurred when using the automated identification systems Vitek 2 and Phoenix, and was due to delayed positivity for ornithine decarboxylase and motility. Subculture and prolonged incubation resulted in positive results for ornithine decarboxylase and for motility. It could be shown by RAPD-analysis that the E. aerogenes strains belonged to different genotypes. Conclusions Clinical E. aerogenes isolates can be easily misidentified as Klebsiella due to delayed positivity for ornithine decarboxylase and motility. The phenomenon may be widespread, since it was shown to occur among genotypically unrelated strains from different hospitals and different isolation dates. A useful clue for correct identification is the presence of an inducible β-lactamase, which is highly unusual for K. pneumoniae. In several instances, the use of genotypic techniques like tDNA-PCR may circumvent problems of phenotypic identification. PMID:15619329

Plasmid-Mediated Resistance to Expanded-Spectrum Cephalosporins among Enterobacter aerogenes Strains

PubMed Central

Pitout, Johann D. D.; Thomson, Kenneth S.; Hanson, Nancy D.; Ehrhardt, Anton F.; Coudron, Philip; Sanders, Christine C.

1998-01-01

Resistance to expanded-spectrum cephalosporins commonly develops in Enterobacter aerogenes during therapy due to selection of mutants producing high levels of the chromosomal Bush group 1 β-lactamase. Recently, resistant strains producing plasmid-mediated extended-spectrum β-lactamases (ESBLs) have been isolated as well. A study was designed to investigate ESBL production among 31 clinical isolates of E. aerogenes from Richmond, Va., with decreased susceptibility to expanded-spectrum cephalosporins and a positive double-disk potentiation test. Antibiotic susceptibility was determined by standard disk diffusion and agar dilution procedures. β-Lactamases were investigated by an isoelectric focusing overlay technique which simultaneously determined isoelectric points (pIs) and substrate or inhibitor profiles. Decreased susceptibility to cefotaxime, ceftazidime, and aztreonam (MIC range, 1 to 64 μg/ml) was detected and associated with resistance to gentamicin and trimethoprim-sulfamethoxazole. All strains produced an inducible Bush group 1 β-lactamase (pI 8.3). Twenty-nine of the 31 isolates also produced an enzyme similar to SHV-4 (pI 7.8), while 1 isolate each produced an enzyme similar to SHV-3 (pI 6.9) and to SHV-5 (pI 8.2). The three different SHV-derived ESBLs were transferred by transconjugation to Escherichia coli C600N and amplified by PCR. Plasmid profiles of the clinical isolates showed a variety of different large plasmids. Because of the linkage of resistance to aminoglycosides and trimethoprim-sulfamethoxazole with ESBL production, it is possible that the usage of these drugs was responsible for selecting plasmid-mediated resistance to extended-spectrum cephalosporins in E. aerogenes. Furthermore, it is important that strains such as these be recognized, because they can be responsible for institutional spread of resistance genes. PMID:9517938

Failure of the MicroScan WalkAway System To Detect Heteroresistance to Carbapenems in a Patient with Enterobacter aerogenes Bacteremia▿

PubMed Central

Gordon, N. C.; Wareham, D. W.

2009-01-01

We report the failure of the automated MicroScan WalkAway system to detect carbapenem heteroresistance in Enterobacter aerogenes. Carbapenem resistance has become an increasing concern in recent years, and robust surveillance is required to prevent dissemination of resistant strains. Reliance on automated systems may delay the detection of emerging resistance. PMID:19641071

Impact of an energy-conserving strategy on succinate production under weak acidic and anaerobic conditions in Enterobacter aerogenes.

PubMed

Tajima, Yoshinori; Yamamoto, Yoko; Fukui, Keita; Nishio, Yousuke; Hashiguchi, Kenichi; Usuda, Yoshihiro; Sode, Koji

2015-06-11

Succinate is an important C4 building block chemical, and its production via fermentative processes in bacteria has many practical applications in the biotechnology field. One of the major goals of optimizing the bacterium-based succinate production process is to lower the culture pH from the current neutral conditions, as this would reduce total production costs. In our previous studies, we selected Enterobacter aerogenes, a rapid glucose assimilator at pH 5.0, in order to construct a metabolically engineered strain that could produce succinate under weakly acidic conditions. This engineered strain produced succinate from glucose with a 72.7% (g/g) yield at pH 5.7, with a volumetric productivity of 0.23 g/L/h. Although this demonstrates proof-of-concept that bacterium-based succinate fermentation can be improved under weakly acidic conditions, several parameters still required further optimization. In this study, we genetically modified an E. aerogenes strain previously developed in our laboratory in order to increase the production of ATP during succinate synthesis, as we inferred that this would positively impact succinate biosynthesis. This led to the development of the ES08ΔptsG strain, which contains the following modifications: chromosomally expressed Actinobacillus succinogenes phosphoenolpyruvate carboxykinase, enhanced fumarate reductase, inactivated pyruvate formate lyase, pyruvate oxidase, and glucose-phosphotransferase permease (enzyme IIBC(Glc)). This strain produced 55.4 g/L succinate from glucose, with 1.8 g/L acetate as the major byproduct at pH 5.7 and anaerobic conditions. The succinate yield and volumetric productivity of this strain were 86.8% and 0.92 g/L/h, respectively. Focusing on increasing net ATP production during succinate synthesis leads to increased succinate yield and volumetric productivity in E. aerogenes. We propose that the metabolically engineered E. aerogenes ES08ΔptsG strain, which effectively produces succinate under weakly

Metabolic engineering of Enterobacter aerogenes for 2,3-butanediol production from sugarcane bagasse hydrolysate.

PubMed

Um, Jaeyong; Kim, Duck Gyun; Jung, Moo-Young; Saratale, Ganesh D; Oh, Min-Kyu

2017-12-01

The pathway engineering of Enterobacter aerogenes was attempted to improve its production capability of 2,3-butanediol from lignocellulosic biomass. In the medium containing glucose and xylose mixture as carbon sources, the gene deletion of pflB improved 2,3-butanediol carbon yield by 40%, while the deletion of ptsG increased xylose consumption rate significantly, improving the productivity at 12 hr by 70%. The constructed strain, EMY-22-galP, overexpressing glucose transporter (galP) in the triple gene knockout E. aerogenes, ldhA, pflB, and ptsG, provided the highest 2,3-butanediol titer and yield at 12 hr flask cultivation. Sugarcane bagasse was pretreated with green liquor, a solution containing Na 2 CO 3 and Na 2 SO 3 and was hydrolyzed by enzymes. The resulting hydrolysate was used as a carbon source for 2,3-butanediol production. After 72 hr in fermentation, the yield of 0.395g/g sugar was achieved, suggesting an economic production of 2,3-butanediol was possible from lignocellulosic biomass with the metabolically engineered strain. Copyright © 2017 Elsevier Ltd. All rights reserved.

Polygalacturonase production by calcium alginate immobilized Enterobacter aerogenes NBO2 cells.

PubMed

Darah, I; Nisha, M; Lim, Sheh-Hong

2015-03-01

Bacterial cells of Enterobacter aerogenes NBO2 were entrapped in calcium alginate beads in order to enhance polygalacturonase production compared to free cells. The optimized condition of 5 % (w/v) sodium alginate concentration, agitation speed of 250 rpm, and 15 beads of calcium alginate with inoculum size of 4 % (v/v; 5.4 × 10(7) cells/ml) produced 23.48 U/mL of polygalacturonase compared to free cells of 18.54 U/ml. There was about 26.6 % increment in polygalaturonase production. However, in this study, there was 296.6 % of increment in polygalacturonase production after improvement parameters compared to before improvement parameters of calcium alginate bead immobilization cells (5.92 U/ml). This research has indicated that optimized physical parameters of calcium alginate bead immobilization cells have significantly enhanced the production of polygalacturonase.

Identification of Ideal Multi-targeting Bioactive Compounds Against Mur Ligases of Enterobacter aerogenes and Its Binding Mechanism in Comparison with Chemical Inhibitors.

PubMed

Chakkyarath, Vijina; Natarajan, Jeyakumar

2017-10-31

Enterobacter aerogenes have been reported as important opportunistic and multi-resistant bacterial pathogens for humans during the last three decades in hospital wards. The emergence of drug-resistant E. aerogenes demands the need for developing new drugs. Peptidoglycan is an important component of the cell wall of bacteria and the peptidoglycan biochemical pathway is considered as the best source of antibacterial targets. Within this pathway, four Mur ligases MurC, MurD, MurE, and MurF are responsible for the successive additions of L-alanine and suitable targets for developing novel antibacterial drugs. As an inference from this fact, we modeled the three-dimensional structure of above Mur ligases using best template structures available in PDB and analyzed its common binding features. Structural refinement and energy minimization of the predicted Mur ligases models is also being done using molecular dynamics studies. The models of Mur ligases were further investigated for in silico docking studies using bioactive plant compounds from the literature. Interestingly, these results indicate that four plant compounds Isojuripidine, Atroviolacegenin, Porrigenin B, and Nummularogenin showing better docking results in terms of binding energy and number of hydrogen bonds. All these four compounds are spirostan-based compounds with differences in side chains and the amino acid such as ASN, LYS, THR, HIS, ARG (polar) and PHE, GLY, VAL, ALA, MET (non-polar) playing active role in binding site of all four Mur ligases. Overall, in the predicted model, the four plant compounds with its binding features could pave way to design novel multi-targeted antibacterial plant-based bioactive compounds specific to Mur ligases for the treatment of Enterobacter infections.

Evaluation of the Rapid Polymyxin NP Test for Polymyxin B Resistance Detection Using Enterobacter cloacae and Enterobacter aerogenes Isolates.

PubMed

Simar, Shelby; Sibley, Diane; Ashcraft, Deborah; Pankey, George

2017-10-01

Polymyxin resistance is an increasing problem worldwide. Currently, determining susceptibility to polymyxins is problematic and lengthy. Polymyxins diffuse poorly into agar, potentially giving inaccurate disk diffusion and Etest results. A rapid screening test (2 h) for the detection of polymyxin resistance in Enterobacteriaceae , developed by P. Nordmann and L. Poirel (rapid polymyxin NP test) in 2016, detects glucose metabolization in the presence of polymyxin E (PE) and PB via pH-induced color change. The sensitivity and specificity were 99.3 and 95.4%, respectively, with results obtained in ≤2 h. Our goal was to evaluate this test using PB against larger numbers of Enterobacter A total of 143 nonduplicate Enterobacter isolates (102 E. cloacae complex, 41 E. aerogenes ) were tested, including 136 collected from Ochsner Health System patients from March to May 2016 and 7 previously determined PB-resistant E. cloacae isolates from JMI Laboratories. MICs were determined via broth microdilution. For the rapid polymyxin NP test, a color change from orange to yellow is positive; a weak/no color change is deemed negative after 4 h. Of 143 Enterobacter isolates, 25 were determined to be PB resistant by broth microdilution (MIC > 2 μg/ml), including all 7 JMI isolates. Of these 25, 7 were positive by the rapid polymyxin NP test (included 3/7 JMI isolates). All 118 isolates determined to be PB susceptible by broth microdilution were NP test negative. The sensitivity and specificity for the rapid polymyxin NP test were 25 and 100%, respectively, compared to broth microdilution. Although the rapid polymyxin NP test is a much faster method (2 to 4 h) for polymyxin resistance determination compared to broth microdilution (16 to 20 h), our study indicates that it may be subject to limitations when testing Enterobacter . Copyright © 2017 American Society for Microbiology.

Changes in ciprofloxacin resistance levels in Enterobacter aerogenes isolates associated with variable expression of the aac(6')-Ib-cr gene.

PubMed

Ruiz, Elena; Ocampo-Sosa, Alain A; Alcoba-Flórez, Julia; Román, Elena; Arlet, Guillaume; Torres, Carmen; Martínez-Martínez, Luis

2012-02-01

Two closely related Enterobacter aerogenes isolates presented a new identical aac(6')-Ib-cr genetic environment, including IS26. One isolate showed lower MICs of ciprofloxacin, norfloxacin, tobramycin, and amikacin and decreased expression of aac(6')-Ib-cr, which might be related to a 12-bp deletion causing a displacement of the -10 box upstream of the aac(6')-Ib-cr gene.

Bioconversion of glycerol to ethanol by a mutant Enterobacter aerogenes

PubMed Central

2012-01-01

The main objective of this research is to develop, by adaptive evolution, mutant strains of Enterobacter aerogenes ATCC 13048 that are capable of withstanding high glycerol concentration as well as resisting ethanol-inhibition. The mutant will be used for high ethanol fermentation from glycerol feedstock. Ethanol production from pure (P-) and recovered (R-) glycerol using the stock was evaluated. A six-tube-subculture-generations method was used for developing the mutant. This involved subculturing the organism six consecutive times in tubes containing the same glycerol and ethanol concentrations at the same culture conditions. Then, the glycerol and/or ethanol concentration was increased and the six subculture generations were repeated. A strain capable of growing in 200 g/L glycerol and 30 g/L ethanol was obtained. The ability of this mutant, vis-à-vis the original strain, in utilizing glycerol in a high glycerol containing medium, with the concomitant ethanol yield, was assessed. Tryptic soy broth without dextrose (TSB) was used as the fermentation medium. Fermentation products were analyzed using HPLC. In a 20 g/L glycerol TSB, E. aerogenes ATCC 13048 converted 18.5 g/L P-glycerol and 17.8 g/L R-glycerol into 12 and 12.8 g/L ethanol, respectively. In a 50 g/L P-glycerol TSB, it utilized only 15.6 g/L glycerol; but the new strain used up 39 g/L, yielding 20 g/L ethanol after 120 h, an equivalence of 1.02 mol ethanol/mol-glycerol. This is the highest ethanol yield reported from glycerol bioconversion. The result of this P-glycerol fermentation can be duplicated using the R-glycerol from biodiesel production. PMID:22455837

Co-fermentation of carbon sources by Enterobacter aerogenes ATCC 29007 to enhance the production of bioethanol.

PubMed

Thapa, Laxmi Prasad; Lee, Sang Jun; Yang, Xiao Guang; Yoo, Hah Young; Kim, Sung Bong; Park, Chulhwan; Kim, Seung Wook

2014-06-01

We investigated the enhancement of bioethanol production in Enterobacter aerogenes ATCC 29007 by co-fermentation of carbon sources such as glycerol, glucose, galactose, sucrose, fructose, xylose, starch, mannitol and citric acid. Biofuel production increases with increasing growth rate of microorganisms; that is why we investigated the optimal growth rate of E. aerogenes ATCC 29007, using mixtures of different carbon sources with glycerol. E. aerogenes ATCC 29007 was incubated in media containing each carbon source and glycerol; growth rate and bioethanol production improved in all cases compared to those in medium containing glycerol alone. The growth rate and bioethanol production were highest with mannitol. Fermentation was carried out at 37 °C for 18 h, pH 7, using 50 mL defined production medium in 100 mL serum bottles at 200 rpm. Bioethanol production under optimized conditions in medium containing 16 g/L mannitol and 20 g/L glycerol increased sixfold (32.10 g/L) than that containing glycerol alone (5.23 g/L) as the carbon source in anaerobic conditions. Similarly, bioethanol production using free cells in continuous co-fermentation also improved (27.28 g/L) when 90.37 % of 16 g/L mannitol and 67.15 % of 20 g/L glycerol were used. Although naturally existing or engineered microorganisms can ferment mixed sugars sequentially, the preferential utilization of glucose to non-glucose sugars often results in lower overall yield and productivity of ethanol. Here, we present new findings in E. aerogenes ATCC 29007 that can be used to improve bioethanol production by simultaneous co-fermentation of glycerol and mannitol.

Draft genome sequence of a multidrug-resistant KPC-2-producing Enterobacter aerogenes isolated from a hospitalised patient in Brazil.

PubMed

Moura, Quézia; Fernandes, Miriam R; Cerdeira, Louise; Nhambe, Lúcia F; Ienne, Susan; Souza, Tiago A; Lincopan, Nilton

2017-09-01

Multidrug-resistant (MDR) Enterobacter aerogenes strains are frequently associated with nosocomial infections and high mortality rates, representing a serious public health problem. The aim of this study was to present the draft genome sequence of a MDR KPC-2-producing E. aerogenes isolated from a perineal swab of a hospitalised patient in Brazil. Genomic DNA was sequenced using an Illumina MiSeq platform. De novo genome assembly was carried out using the A5-Miseq pipeline, and whole-genome sequence analysis was performed using tools from the Center for Genomic Epidemiology. The strain harboured resistance genes to β-lactams, aminoglycosides, sulphonamides and trimethoprim in addition to genes encoding multidrug efflux system proteins, a quaternary ammonium transporter and heavy metal efflux system proteins. In addition, the strain harboured genes encoding diverse virulence factors. These data might allow a better understanding of the genetic basis of antimicrobial resistance and virulence in E. aerogenes strains. Copyright © 2017 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved.

The rhizome of the multidrug-resistant Enterobacter aerogenes genome reveals how new "killer bugs" are created because of a sympatric lifestyle.

PubMed

Diene, Seydina M; Merhej, Vicky; Henry, Mireille; El Filali, Adil; Roux, Véronique; Robert, Catherine; Azza, Saïd; Gavory, Frederick; Barbe, Valérie; La Scola, Bernard; Raoult, Didier; Rolain, Jean-Marc

2013-02-01

Here, we sequenced the 5,419,609 bp circular genome of an Enterobacter aerogenes clinical isolate that killed a patient and was resistant to almost all current antibiotics (except gentamicin) commonly used to treat Enterobacterial infections, including colistin. Genomic and phylogenetic analyses explain the discrepancies of this bacterium and show that its core genome originates from another genus, Klebsiella. Atypical characteristics of this bacterium (i.e., motility, presence of ornithine decarboxylase, and lack of urease activity) are attributed to genomic mosaicism, by acquisition of additional genes, such as the complete 60,582 bp flagellar assembly operon acquired "en bloc" from the genus Serratia. The genealogic tree of the 162,202 bp multidrug-resistant conjugative plasmid shows that it is a chimera of transposons and integrative conjugative elements from various bacterial origins, resembling a rhizome. Moreover, we demonstrate biologically that a G53S mutation in the pmrA gene results in colistin resistance. E. aerogenes has a large RNA population comprising 8 rRNA operons and 87 cognate tRNAs that have the ability to translate transferred genes that use different codons, as exemplified by the significantly different codon usage between genes from the core genome and the "mobilome." On the basis of our findings, the evolution of this bacterium to become a "killer bug" with new genomic repertoires was from three criteria that are "opportunity, power, and usage" to indicate a sympatric lifestyle: "opportunity" to meet other bacteria and exchange foreign sequences since this bacteria was similar to sympatric bacteria; "power" to integrate these foreign sequences such as the acquisition of several mobile genetic elements (plasmids, integrative conjugative element, prophages, transposons, flagellar assembly system, etc.) found in his genome; and "usage" to have the ability to translate these sequences including those from rare codons to serve as a translator of

Identification and evolution of drug efflux pump in clinical Enterobacter aerogenes strains isolated in 1995 and 2003.

PubMed

Chevalier, Jacqueline; Mulfinger, Céline; Garnotel, Eric; Nicolas, Pierre; Davin-Régli, Anne; Pagès, Jean-Marie

2008-09-12

The high mortality impact of infectious diseases will increase due to accelerated evolution of antibiotic resistance in important human pathogens. Development of antibiotic resistance is a evolutionary process inducing the erosion of the effectiveness of our arsenal of antibiotics. Resistance is not necessarily limited to a single class of antibacterial agents but may affect many unrelated compounds; this is termed 'multidrug resistance' (MDR). The major mechanism of MDR is the active expulsion of drugs by bacterial pumps; the treatment of gram negative bacterial infections is compromised due to resistance mechanisms including the expression of efflux pumps that actively expel various usual antibiotics (beta-lactams, quinolones, ...). Enterobacter aerogenes has emerged among Enterobacteriaceae associated hospital infections during the last twenty years due to its faculty of adaptation to antibiotic stresses. Clinical isolates of E. aerogenes belonging to two strain collections isolated in 1995 and 2003 respectively, were screened to assess the involvement of efflux pumps in antibiotic resistance. Drug susceptibility assays were performed on all bacterial isolates and an efflux pump inhibitor (PAbetaN) previously characterized allowed to decipher the role of efflux in the resistance. Accumulation of labelled chloramphenicol was monitored in the presence of an energy poison to determine the involvement of active efflux on the antibiotic intracellular concentrations. The presence of the PAbetaN-susceptible efflux system was also identified in resistant E. aerogenes strains. For the first time a noticeable increase in clinical isolates containing an efflux mechanism susceptible to pump inhibitor is report within an 8 year period. After the emergence of extended spectrum beta-lactamases in E. aerogenes and the recent characterisation of porin mutations in clinical isolates, this study describing an increase in inhibitor-susceptible efflux throws light on a new step in

Identification and Evolution of Drug Efflux Pump in Clinical Enterobacter aerogenes Strains Isolated in 1995 and 2003

PubMed Central

Garnotel, Eric; Nicolas, Pierre; Davin-Régli, Anne; Pagès, Jean-Marie

2008-01-01

Background The high mortality impact of infectious diseases will increase due to accelerated evolution of antibiotic resistance in important human pathogens. Development of antibiotic resistance is a evolutionary process inducing the erosion of the effectiveness of our arsenal of antibiotics. Resistance is not necessarily limited to a single class of antibacterial agents but may affect many unrelated compounds; this is termed ‘multidrug resistance’ (MDR). The major mechanism of MDR is the active expulsion of drugs by bacterial pumps; the treatment of Gram negative bacterial infections is compromised due to resistance mechanisms including the expression of efflux pumps that actively expel various usual antibiotics (ß-lactams, quinolones, …). Methodology/Principal Findings Enterobacter aerogenes has emerged among Enterobacteriaceae associated hospital infections during the last twenty years due to its faculty of adaptation to antibiotic stresses. Clinical isolates of E. aerogenes belonging to two strain collections isolated in 1995 and 2003 respectively, were screened to assess the involvement of efflux pumps in antibiotic resistance. Drug susceptibility assays were performed on all bacterial isolates and an efflux pump inhibitor (PAßN) previously characterized allowed to decipher the role of efflux in the resistance. Accumulation of labelled chloramphenicol was monitored in the presence of an energy poison to determine the involvement of active efflux on the antibiotic intracellular concentrations. The presence of the PAßN-susceptible efflux system was also identified in resistant E. aerogenes strains. Conclusions/Significance For the first time a noticeable increase in clinical isolates containing an efflux mechanism susceptible to pump inhibitor is report within an 8 year period. After the emergence of extended spectrum ß-lactamases in E. aerogenes and the recent characterisation of porin mutations in clinical isolates, this study describing an increase

Optimization of cultural conditions for conversion of glycerol to ethanol by Enterobacter aerogenes S012

PubMed Central

2013-01-01

The aim of this research is to optimize the cultural conditions for the conversion of glycerol to ethanol by Enterobacter aerogenes S012. Taguchi method was used to screen the cultural conditions based on their signal to noise ratio (SN). Temperature (°C), agitation speed (rpm) and time (h) were found to have the highest influence on both glycerol utilization and ethanol production by the organism while pH had the lowest. Full factorial design, statistical analysis, and regression model equation were used to optimize the selected cultural parameters for maximum ethanol production. The result showed that fermentation at 38°C and 200 rpm for 48 h would be ideal for the bacteria to produce maximum amount of ethanol from glycerol. At these optimum conditions, ethanol production, yield and productivity were 25.4 g/l, 0.53 g/l/h, and 1.12 mol/mol-glycerol, repectively. Ethanol production increased to 26.5 g/l while yield and productivity decreased to 1.04 mol/mol-glycerol and 0.37 g/l/h, respectively, after 72 h. Analysis of the fermentation products was performed using HPLC, while anaerobic condition was created by purging the fermentation vessel with nitrogen gas. PMID:23388539

Biohydrogen and polyhydroxyalkanoate co-production by Enterobacter aerogenes and Rhodobacter sphaeroides from Calophyllum inophyllum oil cake.

PubMed

Arumugam, A; Sandhya, M; Ponnusami, V

2014-07-01

The feasibility of coupled biohydrogen and polyhydroxyalkanoate production by Enterobacter aerogenes and Rhodobacter sphaeroides using Calophyllum inophyllum oil cake was studied under dark and photo fermentation conditions. The utilization of a non-edible acidic oil cake (C. inophyllum), and exploitation of a modified minimal salt media led to reduction in the cost of media. Cost of fermentation is reduced by implementation of alternate dark-photo fermentative periods and through the use of a co-culture consisting of a dark fermentative (E. aerogenes) and a photo fermentative (R. sphaeroides) bacterium. The biohydrogen and polyhydroxyalkanoate produced were 7.95 L H2/L media and 10.73 g/L media, respectively, under alternate dark and photo fermentation and were 3.23 L H2/L media and 5.6g/L media, respectively under complete dark fermentation. The characteristics of the oil cake and alternate dark (16 h) and photo (8h) fermentative conditions were found to be supportive in producing high biohydrogen and polyhydroxyalkanoate (PHA) yield. Copyright © 2014 Elsevier Ltd. All rights reserved.

Enhancing hydrogen production of Enterobacter aerogenes by heterologous expression of hydrogenase genes originated from Synechocystis sp.

PubMed

Song, Wenlu; Cheng, Jun; Zhao, Jinfang; Zhang, Chuanxi; Zhou, Junhu; Cen, Kefa

2016-09-01

The hydrogenase genes (hoxEFUYH) of Synechocystis sp. PCC 6803 were cloned and heterologously expressed in Enterobacter aerogenes ATCC13408 for the first time in this study, and the hydrogen yield was significantly enhanced using the recombinant strain. A recombinant plasmid containing the gene in-frame with Glutathione-S-Transferase (GST) gene was transformed into E. aerogenes ATCC13408 to produce a GST-fusion protein. SDS-PAGE and western blot analysis confirm the successful expression of the hox genes. The hydrogenase activity of the recombinant strain is 237.6±9.3ml/(g-DW·h), which is 152% higher than the wild strain. The hydrogen yield of the recombinant strain is 298.3ml/g-glucose, which is 88% higher than the wild strain. During hydrogen fermentation, the recombinant strain produces more acetate and butyrate, but less ethanol. This is corresponding to the NADH metabolism in the cell due to the higher hydrogenase activity with the heterologous expression of hox genes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Physiological characterisation of the efflux pump system of antibiotic-susceptible and multidrug-resistant Enterobacter aerogenes.

PubMed

Martins, A; Spengler, G; Martins, M; Rodrigues, L; Viveiros, M; Davin-Regli, A; Chevalier, J; Couto, I; Pagès, J M; Amaral, L

2010-10-01

Enterobacter aerogenes predominates amongst Enterobacteriaceae species that are increasingly reported as producers of extended-spectrum beta-lactamases. Although this mechanism of resistance to beta-lactams is important, other mechanisms bestowing a multidrug-resistant (MDR) phenotype in this species are now well documented. Amongst these mechanisms is the overexpression of efflux pumps that extrude structurally unrelated antibiotics prior to their reaching their targets. Interestingly, although knowledge of the genetic background behind efflux pumps is rapidly advancing, few studies assess the physiological nature of the overall efflux pump system of this, or for that matter any other, bacterium. The study reported here evaluates physiologically the efflux pump system of an E. aerogenes ATCC reference as well as two strains whose MDR phenotypes are mediated by overexpressed efflux pumps. The activities of the efflux pumps in these strains are modulated by pH and glucose, although the effects of the latter are essentially restricted to pH 8, suggesting the presence of two general efflux pump systems, i.e. proton-motive force-dependent and ABC transporter types, respectively. Copyright 2010 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

Biodegradation of acrylamide by Enterobacter aerogenes isolated from wastewater in Thailand.

PubMed

Buranasilp, Kanokhathai; Charoenpanich, Jittima

2011-01-01

A widespread use of acrylamide, probably a neurotoxicant and carcinogen, in various industrial processes has led to environmental contamination. Fortunately, some microorganisms are able to derive energy from acrylamide. In the present work, we reported the isolation and characterization of a novel acrylamide-degrading bacterium from domestic wastewater in Chonburi, Thailand. The strain grew well in the presence of acrylamide as 0.5% (W/V), at pH 6.0 to 9.0 and 25 degrees C. Identification based on biochemical characteristics and 16S rRNA gene sequence identified the strain as Enterobacter aerogenes. Degradation of acrylamide to acrylic acid started in the late logarithmic growth phase as a biomass-dependent pattern. Specificity of cell-free supernatant towards amides completely degraded butyramide and urea and 86% of lactamide. Moderate degradation took place in other amides with that by formamide > benzamide > acetamide > cyanoacetamide > propionamide. No degradation was detected in the reactions of N,N-methylene bisacrylamide, sodium azide, thioacetamide, and iodoacetamide. These results highlighted the potential of this bacterium in the cleanup of acrylamide/amide in the environment.

Formate and Nitrate Utilization in Enterobacter aerogenes for Semi-Anaerobic Production of Isobutanol.

PubMed

Jung, Hwi-Min; Kim, Yong Hwan; Oh, Min-Kyu

2017-11-01

Anaerobic bioprocessing is preferred because of its economic advantages. However, low productivity and decreased growth of the host strain have limited the use of the anaerobic process. Anaerobic respiration can be applied to anoxic processing using formate and nitrate metabolism to improve the productivity of value-added metabolites. A isobutanol-producing strains is constructed using Enterobacter aerogenes as a host strain by metabolic engineering approaches. The byproduct pathway (ldhA, budA, and pflB) is knocked out, and heterologous keto-acid decarboxylase (kivD) and alcohol dehydrogenase (adhA) are expressed along with the L-valine synthesis pathway (ilvCD and budB). The pyruvate formate-lyase mutant shows decreased growth rates when cultivated in semi-anaerobic conditions, which results in a decline in productivity. When formate and nitrate are supplied in the culture medium, the growth rates and amount of isobutanol production is restored (4.4 g L -1 , 0.23 g g -1 glucose, 0.18 g L -1  h -1 ). To determine the function of the formate and nitrate coupling reaction system, the mutant strains that could not utilize formate or nitrate is contructed. Decreased growth and productivity are observed in the nitrate reductase (narG) mutant strain. This is the first report of engineering isobutanol-producing E. aerogenes to increase strain fitness via augmentation of formate and nitrate metabolism during anaerobic cultivation. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Histamine production by Enterobacter aerogenes in sailfish and milkfish at various storage temperatures.

PubMed

Tsai, Yung-Hsiang; Chang, Shiou-Chung; Kung, Hsien-Feng; Wei, Cheng-I; Hwang, Deng-Fwu

2005-08-01

Enterobacter aerogenes was studied for its growth and ability to promote the formation of total volatile base nitrogen (TVBN) and histamine in sailfish (Istiophorus platypterus) and milkfish (Chanos chanos) stored at various temperatures from -20 to 37 degrees C. The optimal temperature for bacterial growth in both fish species was 25 degrees C, whereas the optimal temperature for histamine formation was 37 degrees C. The two fish species inoculated with E. aerogenes, when not properly stored at low temperatures such as 15 degrees C for 36 h, formed histamine at above the U.S. Food and Drug Administration hazardous guideline level of 50 mg/100 g. Milkfish was a better substrate than sailfish for histamine formation by bacterial histidine decarboxylation at elevated temperatures (> 15 degrees C). Although higher contents of TVBN were detected in the spiked sailfish than milkfish during the same storage time at temperatures above 15 degrees C, the use of the 30-mg/100 g level of TVBN as a determination index for fish quality and decomposition was not a good criterion for assessing potential histamine hazard for both fish species. Bacterial growth was controlled by cold storage of the fish at 4 degrees C or below, but histamine formation was stopped only by frozen storage. Once the frozen fish samples were thawed and stored at 25 degrees C, histamine started to accumulate rapidly and reached levels greater than the hazardous action level in 36 h.

Identification of EayjjPB encoding a dicarboxylate transporter important for succinate production under aerobic and anaerobic conditions in Enterobacter aerogenes.

PubMed

Fukui, Keita; Nanatani, Kei; Hara, Yoshihiko; Tokura, Mitsunori; Abe, Keietsu

2018-05-01

Enterobacter aerogenes, a gram-negative, rod-shaped bacterium, is an effective producer of succinate from glucose via the reductive tricarboxylic acid cycle under anaerobic conditions. However, to date, succinate-exporter genes have not been identified in E. aerogenes, although succinate exporters have a large impact on fermentative succinate production. Recently, we genetically identified yjjP and yjjB, as genes encoding a succinate transporter in Escherichia coli. Evaluation of the yjjPB homologs in E. aerogenes (EayjjPB genes) showed that succinate accumulation increased from 4.1 g L -1 to 9.1 g L -1 when the EayjjPB genes were expressed under aerobic conditions. Under anaerobic conditions, succinate yield increased from 53% to 60% by EayjjPB expression and decreased to 48% by deletion of EayjjPB. Furthermore, the production levels of fumarate and malate, which are intermediates of the succinate-biosynthesis pathway, were also increased by EayjjPB expression. A complementation assay conducted in Corynebacterium glutamicum strain AJ110655ΔsucE1 demonstrated that both EaYjjP and EaYjjB are required for the restoration of succinate production. Taken together, these results suggest that EaYjjPB function as a dicarboxylate transporter in E. aerogenes and that the products of both genes are required for dicarboxylate transport. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Hospital clonal dissemination of Enterobacter aerogenes producing carbapenemase KPC-2 in a Chinese teaching hospital.

PubMed

Qin, Xiaohua; Yang, Yang; Hu, Fupin; Zhu, Demei

2014-02-01

Carbapenems are first-line agents for the treatment of serious nosocomial infections caused by multidrug-resistant Enterobacteriaceae. However, resistance to carbapenems has increased dramatically among Enterobacteriaceae in our hospital. In this study, we report clonal dissemination caused by carbapenem-resistant Enterobacter aerogenes (CREA). In 2011, CREA was identified from 12 patients admitted to the neurosurgical ward. All 12 clinical isolates were non-susceptible to cefotaxime, ceftazidime, cefoxitin, ertapenem, imipenem or meropenem. All isolates carried the gene encoding Klebsiella pneumoniae carbapenemase-2 (KPC-2), except for the isolate E4. However, a remarkably lower expression level of the porin OmpF was detected in the non-KPC-2-producing isolate E4 on SDS-PAGE compared with the carbapenem-susceptible isolate. Epidemiological and molecular investigations showed that a single E. aerogenes strain (PFGE type A), including seven KPC-2-producing clinical isolates, was primarily responsible for the first isolation and subsequent dissemination. In a case-control study, we identified risk factors for infection/colonization with CREA. Mechanical ventilation, the changing of sickbeds and previous use of broad-spectrum antibiotics were identified as potential risk factors. Our findings suggest that further studies should focus on judicious use of available antibiotics, implementation of active antibiotic resistance surveillance and strict implementation of infection-control measures to avoid the rapid spread or clonal dissemination caused by carbapenem-resistant Enterobacteriaceae in healthcare facilities.

Epidemiology of Extended-Spectrum β-Lactamase-Producing Enterobacter Isolates in a Spanish Hospital during a 12-Year Period

PubMed Central

Cantón, Rafael; Oliver, Antonio; Coque, Teresa M.; Varela, María del Carmen; Pérez-Díaz, José Claudio; Baquero, Fernando

2002-01-01

Fifteen Enterobacter clinical isolates (11 Enterobacter cloacae isolates, 3 Enterobacter aerogenes isolates, and 1 Enterobacter gergoviae isolate), representing 0.4% of all Enterobacter isolates recovered in our hospital from 1989 to 2000, were suspected of harboring an extended-spectrum β-lactamase (ESBL). These isolates were recovered from 14 different patients. ESBLs were transferred by conjugation into an Escherichia coli recipient strain. Pulsed-field gel electrophoresis (PFGE) revealed a single clone of E. aerogenes and six different clones of E. cloacae. Four of these E. cloacae clonal types were represented by only one isolate each, but the other two were represented by three and four isolates, respectively. Isoelectric focusing, susceptibility phenotyping, PCR analysis, and sequencing demonstrated the presence of three different ESBLs. The most frequent was the recently characterized CTX-M-10 ESBL, which was found in the E. gergoviae isolate and in all but one of the E. cloacae isolates. The remaining E. cloacae isolate harbored a TEM-27 ESBL, and the three E. aerogenes isolates harbored a TEM-24 ESBL. PFGE revealed that our E. aerogenes strain was indistinguishable from the French TEM-24-producing E. aerogenes endemic clone. Although a low prevalence of ESBL-producing Enterobacter isolates was found in our institution over a 12-year period, a diversity of nonepidemic E. cloacae clones was detected, as was the persistence of the CTX-M-10 β-lactamase. The presence of the TEM-24-producing E. aerogenes French clone in our institution also demonstrates the intercountry dissemination of ESBL-producing isolates. PMID:11923338

Optimization of organosolv pretreatment of rice straw for enhanced biohydrogen production using Enterobacter aerogenes.

PubMed

Asadi, Nooshin; Zilouei, Hamid

2017-03-01

Ethanol organosolv pretreated rice straw was used to produce biohydrogen using Enterobacter aerogenes. The effect of temperature (120-180°C), residence time (30-90min), and ethanol concentration (45-75%v/v) on the hydrogen yield, residual biomass, and lignin recovery was investigated using RSM. In contrast to the residual solid and lignin recovery, no considerable trend could be observed for the changes in the hydrogen yield at different treatment severities. The maximum hydrogen yield of 19.73mlg -1 straw was obtained at the ethanol concentration of 45%v/v and 180°C for 30min. Furthermore, the potential amount of biohydrogen was estimated in the top ten rice producing nations using the experimental results. Approximately 355.8kt of hydrogen and 11.3Mt of lignin could globally be produced. Based on a Monte Carlo analysis, the production of biohydrogen from rice straw has the lowest risk in China and the highest in Japan. Copyright © 2016 Elsevier Ltd. All rights reserved.

Biohydrogen and Bioethanol Production from Biodiesel-Based Glycerol by Enterobacter aerogenes in a Continuous Stir Tank Reactor

PubMed Central

Jitrwung, Rujira; Yargeau, Viviane

2015-01-01

Crude glycerol from the biodiesel manufacturing process is being produced in increasing quantities due to the expanding number of biodiesel plants. It has been previously shown that, in batch mode, semi-anaerobic fermentation of crude glycerol by Enterobacter aerogenes can produce biohydrogen and bioethanol simultaneously. The present study demonstrated the possible scaling-up of this process from small batches performed in small bottles to a 3.6-L continuous stir tank reactor (CSTR). Fresh feed rate, liquid recycling, pH, mixing speed, glycerol concentration, and waste recycling were optimized for biohydrogen and bioethanol production. Results confirmed that E. aerogenes uses small amounts of oxygen under semi-anaerobic conditions for growth before using oxygen from decomposable salts, mainly NH4NO3, under anaerobic condition to produce hydrogen and ethanol. The optimal conditions were determined to be 500 rpm, pH 6.4, 18.5 g/L crude glycerol (15 g/L glycerol) and 33% liquid recycling for a fresh feed rate of 0.44 mL/min. Using these optimized conditions, the process ran at a lower media cost than previous studies, was stable after 7 days without further inoculation and resulted in yields of 0.86 mol H2/mol glycerol and 0.75 mol ethanol/mole glycerol. PMID:25970750

Biohydrogen and Bioethanol Production from Biodiesel-Based Glycerol by Enterobacter aerogenes in a Continuous Stir Tank Reactor.

PubMed

Jitrwung, Rujira; Yargeau, Viviane

2015-05-11

Crude glycerol from the biodiesel manufacturing process is being produced in increasing quantities due to the expanding number of biodiesel plants. It has been previously shown that, in batch mode, semi-anaerobic fermentation of crude glycerol by Enterobacter aerogenes can produce biohydrogen and bioethanol simultaneously. The present study demonstrated the possible scaling-up of this process from small batches performed in small bottles to a 3.6-L continuous stir tank reactor (CSTR). Fresh feed rate, liquid recycling, pH, mixing speed, glycerol concentration, and waste recycling were optimized for biohydrogen and bioethanol production. Results confirmed that E. aerogenes uses small amounts of oxygen under semi-anaerobic conditions for growth before using oxygen from decomposable salts, mainly NH4NO3, under anaerobic condition to produce hydrogen and ethanol. The optimal conditions were determined to be 500 rpm, pH 6.4, 18.5 g/L crude glycerol (15 g/L glycerol) and 33% liquid recycling for a fresh feed rate of 0.44 mL/min. Using these optimized conditions, the process ran at a lower media cost than previous studies, was stable after 7 days without further inoculation and resulted in yields of 0.86 mol H2/mol glycerol and 0.75 mol ethanol/mole glycerol.

Effect of crude glycerol-derived inhibitors on ethanol production by Enterobacter aerogenes.

PubMed

Lee, Sang Jun; Kim, Sung Bong; Kang, Seong Woo; Han, Sung Ok; Park, Chulhwan; Kim, Seung Wook

2012-01-01

In this study, ethanol production from pure and crude glycerol using Enterobacter aerogenes ATCC 29007 was evaluated under anaerobic culture conditions. Inhibitory effects of substrate concentrations, pH, and salt concentrations were investigated based on crude glycerol components. Ethanol production was performed with pure glycerol concentrations ranging from 5 to 30 g/L to evaluate the effects of substrate concentration and osmotic pressure. The consumed glycerol was 5-14.33 g/L, and the yield of ethanol was higher than 0.75 mol ethanol/mol glycerol after 24 h of cultivation. To evaluate the inhibitory effects of salts (NaCl and KCl), experiments were performed with 0-20 g/L of each salt. Inhibitory effects of salts were strongest at high salt concentrations. The inhibitory effect of pH was performed in the pH range 4-10, and cell growth and ethanol production were highest at pH 5-6. Also, ethanol production was slightly inhibited at low concentration of crude glycerol comparison with pure glycerol. However, significant inhibitory effects were not observed at 1.5 and 2% crude glycerol which showed higher ethanol production compared to pure glycerol.

Alleviation of carbon catabolite repression in Enterobacter aerogenes for efficient utilization of sugarcane molasses for 2,3-butanediol production.

PubMed

Jung, Moo-Young; Jung, Hwi-Min; Lee, Jinwon; Oh, Min-Kyu

2015-01-01

Due to its cost-effectiveness and rich sugar composition, sugarcane molasses is considered to be a promising carbon source for biorefinery. However, the sugar mixture in sugarcane molasses is not consumed as efficiently as glucose in microbial fermentation due to complex interactions among their utilizing pathways, such as carbon catabolite repression (CCR). In this study, 2,3-butanediol-producing Enterobacter aerogenes was engineered to alleviate CCR and improve sugar utilization by modulating its carbon preference. The gene encoding catabolite repressor/activator (Cra) was deleted in the genome of E. aerogenes to increase the fructose consumption rate. However, the deletion mutation repressed sucrose utilization, resulting in the accumulation of sucrose in the fermentation medium. Cra regulation on expression of the scrAB operon involved in sucrose catabolism was verified by reverse transcription and real-time PCR, and the efficiency of sucrose utilization was restored by disrupting the scrR gene and overexpressing the scrAB operon. In addition, overexpression of the ptsG gene involved in glucose utilization enhanced the glucose preference among mixed sugars, which relieved glucose accumulation in fed-batch fermentation. In fed-batch fermentation using sugarcane molasses, the maximum titer of 2,3-butanediol production by the mutant reached 140.0 g/L at 54 h, which was by far the highest titer of 2,3-butanediol with E. aerogenes achieved through genetic engineering. We have developed genetically engineered E. aerogenes as a 2,3-butanediol producer that efficiently utilizes sugarcane molasses. The fermentation efficiency was dramatically improved by the alleviation of CCR and modulation of carbon preference. These results offer a metabolic engineering approach for achieving highly efficient utilization of mixed sugars for the biorefinery industry.

Longer Contact Times Increase Cross-Contamination of Enterobacter aerogenes from Surfaces to Food.

PubMed

Miranda, Robyn C; Schaffner, Donald W

2016-11-01

Bacterial cross-contamination from surfaces to food can contribute to foodborne disease. The cross-contamination rate of Enterobacter aerogenes on household surfaces was evaluated by using scenarios that differed by surface type, food type, contact time (<1, 5, 30, and 300 s), and inoculum matrix (tryptic soy broth or peptone buffer). The surfaces used were stainless steel, tile, wood, and carpet. The food types were watermelon, bread, bread with butter, and gummy candy. Surfaces (25 cm 2 ) were spot inoculated with 1 ml of inoculum and allowed to dry for 5 h, yielding an approximate concentration of 10 7 CFU/surface. Foods (with a 16-cm 2 contact area) were dropped onto the surfaces from a height of 12.5 cm and left to rest as appropriate. Posttransfer, surfaces and foods were placed in sterile filter bags and homogenized or massaged, diluted, and plated on tryptic soy agar. The transfer rate was quantified as the log percent transfer from the surface to the food. Contact time, food, and surface type all had highly significant effects (P < 0.000001) on the log percent transfer of bacteria. The inoculum matrix (tryptic soy broth or peptone buffer) also had a significant effect on transfer (P = 0.013), and most interaction terms were significant. More bacteria transferred to watermelon (∼0.2 to 97%) than to any other food, while the least bacteria transferred to gummy candy (∼0.1 to 62%). Transfer of bacteria to bread (∼0.02 to 94%) was similar to transfer of bacteria to bread with butter (∼0.02 to 82%), and these transfer rates under a given set of conditions were more variable than with watermelon and gummy candy. The popular notion of the "five-second rule" is that food dropped on the floor and left there for <5 s is "safe" because bacteria need time to transfer. The rule has been explored by a single study in the published literature and on at least two television shows. Results from two academic laboratories have been shared through press releases but

Longer Contact Times Increase Cross-Contamination of Enterobacter aerogenes from Surfaces to Food

PubMed Central

Miranda, Robyn C.

2016-01-01

ABSTRACT Bacterial cross-contamination from surfaces to food can contribute to foodborne disease. The cross-contamination rate of Enterobacter aerogenes on household surfaces was evaluated by using scenarios that differed by surface type, food type, contact time (<1, 5, 30, and 300 s), and inoculum matrix (tryptic soy broth or peptone buffer). The surfaces used were stainless steel, tile, wood, and carpet. The food types were watermelon, bread, bread with butter, and gummy candy. Surfaces (25 cm2) were spot inoculated with 1 ml of inoculum and allowed to dry for 5 h, yielding an approximate concentration of 107 CFU/surface. Foods (with a 16-cm2 contact area) were dropped onto the surfaces from a height of 12.5 cm and left to rest as appropriate. Posttransfer, surfaces and foods were placed in sterile filter bags and homogenized or massaged, diluted, and plated on tryptic soy agar. The transfer rate was quantified as the log percent transfer from the surface to the food. Contact time, food, and surface type all had highly significant effects (P < 0.000001) on the log percent transfer of bacteria. The inoculum matrix (tryptic soy broth or peptone buffer) also had a significant effect on transfer (P = 0.013), and most interaction terms were significant. More bacteria transferred to watermelon (∼0.2 to 97%) than to any other food, while the least bacteria transferred to gummy candy (∼0.1 to 62%). Transfer of bacteria to bread (∼0.02 to 94%) was similar to transfer of bacteria to bread with butter (∼0.02 to 82%), and these transfer rates under a given set of conditions were more variable than with watermelon and gummy candy. IMPORTANCE The popular notion of the “five-second rule” is that food dropped on the floor and left there for <5 s is “safe” because bacteria need time to transfer. The rule has been explored by a single study in the published literature and on at least two television shows. Results from two academic laboratories have been shared

Quantitative analysis of the growth of Salmonella stanley during alfalfa sprouting and evaluation of Enterobacter aerogenes as its surrogate.

PubMed

Liu, Bin; Schaffner, Donald W

2007-02-01

Raw seed sprouts have been implicated in several food poisoning outbreaks in the last 10 years. Few studies have included investigations of factors influencing the effectiveness of testing spent irrigation water, and in no studies to date has a nonpathogenic surrogate been identified as suitable for large-scale irrigation water testing trials. Alfalfa seeds were inoculated with Salmonella Stanley or its presumptive surrogate (nalidixic acid-resistant Enterobacter aerogenes) at three concentrations (-3, -30, and -300 CFU/g) and were then transferred into either flasks or a bench top-scale sprouting chamber. Microbial concentrations were determined in seeds, sprouts, and irrigation water at various times during a 4-day sprouting process. Data were fit to logistic regression models, and growth rates and maximum concentrations were compared using the generalized linear model procedure of SAS. No significant differences in growth rates were observed among samples taken from flasks or the chamber. Microbial concentrations in irrigation water were not significantly different from concentrations in sprout samples obtaihed at the same time. E. aerogenes concentrations were similar to those of Salmonella Stanley at corresponding time points for all three inoculum concentrations. Growth rates were also constant regardless of inoculum concentration or strain, except that lower inoculum concentrations resulted in lower final concentrations proportional to their initial concentrations. This research demonstrated that a nonpathogenic easy-to-isolate surrogate (nalidixic acid-resistant E. aerogenes) provides results similar to those obtained with Salmonella Stanley, supporting the use of this surrogate in future large-scale experiments.

Biosensing and bioremediation of Cr(VI) by cell free extract of Enterobacter aerogenes T2.

PubMed

Panda, Jigisha; Sarkar, Priyabrata

2014-01-01

Hexavalent chromium or Cr(VI) enters the environment through several anthropogenic activities and it is highly toxic and carcinogenic. Hence it is required to be detected and remediated from the environment. In this study, low-cost and environment-friendly methods of biosensing and bioremediation of Cr(VI) have been proposed. Crude cell free extract (CFE) of previously isolated Enterobacter aerogenes T2 (GU265554; NII 1111) was prepared and exploited to develop a stable biosensor for direct estimation of Cr(VI) in waste water, by using three electrodes via cyclic voltammetry. For bioremediation studies, a homogeneous solution of commercially available sodium alginate and CFE was added dropwise in a continuously stirred calcium chloride solution. Biologically modified calcium alginate beads were produced and these were further utilized for bioremediation studies. The proposed sensor showed linear response in the range of 10-40 μg L(-1) Cr(VI) and the limit of detection was found to be 6.6 μg L(-1) Cr(VI). No interference was observed in presence of metal ions, e.g., lead, cadmium, arsenic, tin etc., except for insignificant interference with molybdenum and manganese. In bioremediation studies, modified calcium alginate beads showed encouraging removal rate 900 mg Cr(VI)/m(3) water per day with a removal efficiency of 90%, much above than reported in literature. The proposed sensing system could be a viable alternative to costly measurement procedures. Calcium alginate beads, modified with CFE of E. aerogenes, could be used in bioremediation of Cr(VI) since it could work in real conditions with extraordinarily high capacity.

Improved hydrogen production under microaerophilic conditions by overexpression of polyphosphate kinase in Enterobacter aerogenes.

PubMed

Lu, Yuan; Zhang, Chong; Lai, Qiheng; Zhao, Hongxin; Xing, Xin-Hui

2011-02-08

Effects of different microaerophilic conditions on cell growth, glucose consumption, hydrogen production and cellular metabolism of wild Enterobacter aerogenes strain and polyphosphate kinase (PPK) overexpressing strain were systematically studied in this paper, using NaH(2)PO(4) as the phosphate sources. Under different microaerophilic conditions, PPK-overexpressing strain showed better cell growth, glucose consumption and hydrogen production than the wild strain. In the presence of limited oxygen (2.1%) and by PPK overexpression, the hydrogen production per liter of culture, the hydrogen production per cell and the hydrogen yield per mol of glucose increased by 20.1%, 12.3% and 10.8%, respectively, compared with the wild strain under strict anaerobic conditions. Metabolic analysis showed that the increase of the total hydrogen yield was attributed to the improvement of NADH pathway. The result of more reductive cellular oxidation state balance also further demonstrated that, under proper initial microaerophilic conditions and by PPK overexpression, the cell could adjust the cellular redox states and make more energy flow into hydrogen production pathways. Copyright © 2010 Elsevier Inc. All rights reserved.

Improved production of isobutanol in pervaporation-coupled bioreactor using sugarcane bagasse hydrolysate in engineered Enterobacter aerogenes.

PubMed

Jung, Hwi-Min; Lee, Ju Yeon; Lee, Jung-Hyun; Oh, Min-Kyu

2018-07-01

A process of isobutanol production from sugarcane bagasse hydrolysates in Enterobacter aerogenes was developed here with a pervaporation-integrated procedure. Isobutanol pathway was overexpressed in a mutant strain with eliminated byproduct-forming enzymes (LdhA, BudA, and PflB). A glucose-and-xylose-coconsuming ptsG mutant was constructed for effective utilization of lignocellulosic biomass. Toxic effects of isobutanol were alleviated by in situ recovery via a pervaporation procedure. Compared to single-batch fermentation, cell growth and isobutanol titer were improved by 60% and 100%, respectively, in the pervaporation-integrated fermentation process. A lab-made cross-linked polydimethylsiloxane membrane was cast on polyvinylidene fluoride and used in the pervaporation process. The membrane-penetrating condensate contained 55-226 g m -2  h -1 isobutanol with 6-25 g L -1 ethanol after separation. This study offers improved fermentative production of isobutanol from lignocellulosic biomass with a pervaporation procedure. Copyright © 2018 Elsevier Ltd. All rights reserved.

Multidrug resistant bacteria are sensitive to Euphorbia prostrata and six others Cameroonian medicinal plants extracts.

PubMed

Voukeng, Igor K; Beng, Veronique P; Kuete, Victor

2017-07-25

Multidrug resistant (MDR) bacteria are responsible for therapeutic failure and there is an urgent need for novels compounds efficient on them. Eleven methanol extracts from seven Cameroonian medicinal plants were tested for their antibacterial activity using broth micro-dilution method against 36 MDR bacterial strains including Escherichia coli, Enterobacter aerogenes, Enterobacter cloacae, Klebsiella pneumoniae, Providencia stuartii, Pseudomonas aeruginosa and Staphylococcus aureus. Euphorbia prostrata extract was found active against all the 36 tested bacteria including Gram-negative phenotypes over-expressing efflux pumps such as P. aeruginosa PA124, E. aerogenes CM64 and E. coli AG102. E. prostrata had minimal inhibitory concentrations values between 128 and 256 µg/mL on 55.55% of the studied microorganisms. Other plants extract displayed selective antibacterial activity. Results obtained in this study highlight the antibacterial potential of the tested plants and the possible use of E. prostrata to combat bacterial infections including MDR phenotypes.

In Vivo Evolution of Bacterial Resistance in Two Cases of Enterobacter aerogenes Infections during Treatment with Imipenem

PubMed Central

Santini, Sébastien; Pinet, Elizabeth; Claverie, Jean-Michel; Davin-Régli, Anne-Véronique; Pagès, Jean-Marie; Masi, Muriel

2015-01-01

Infections caused by multidrug resistant (MDR) bacteria are a major concern worldwide. Changes in membrane permeability, including decreased influx and/or increased efflux of antibiotics, are known as key contributors of bacterial MDR. Therefore, it is of critical importance to understand molecular mechanisms that link membrane permeability to MDR in order to design new antimicrobial strategies. In this work, we describe genotype-phenotype correlations in Enterobacter aerogenes, a clinically problematic and antibiotic resistant bacterium. To do this, series of clinical isolates have been periodically collected from two patients during chemotherapy with imipenem. The isolates exhibited different levels of resistance towards multiple classes of antibiotics, consistently with the presence or the absence of porins and efflux pumps. Transport assays were used to characterize membrane permeability defects. Simultaneous genome-wide analysis allowed the identification of putative mutations responsible for MDR. The genome of the imipenem-susceptible isolate G7 was sequenced to closure and used as a reference for comparative genomics. This approach uncovered several loci that were specifically mutated in MDR isolates and whose products are known to control membrane permeability. These were omp35 and omp36, encoding the two major porins; rob, encoding a global AraC-type transcriptional activator; cpxA, phoQ and pmrB, encoding sensor kinases of the CpxRA, PhoPQ and PmrAB two-component regulatory systems, respectively. This report provides a comprehensive analysis of membrane alterations relative to mutational steps in the evolution of MDR of a recognized nosocomial pathogen. PMID:26398358

In Vivo Evolution of Bacterial Resistance in Two Cases of Enterobacter aerogenes Infections during Treatment with Imipenem.

PubMed

Philippe, Nadège; Maigre, Laure; Santini, Sébastien; Pinet, Elizabeth; Claverie, Jean-Michel; Davin-Régli, Anne-Véronique; Pagès, Jean-Marie; Masi, Muriel

2015-01-01

Infections caused by multidrug resistant (MDR) bacteria are a major concern worldwide. Changes in membrane permeability, including decreased influx and/or increased efflux of antibiotics, are known as key contributors of bacterial MDR. Therefore, it is of critical importance to understand molecular mechanisms that link membrane permeability to MDR in order to design new antimicrobial strategies. In this work, we describe genotype-phenotype correlations in Enterobacter aerogenes, a clinically problematic and antibiotic resistant bacterium. To do this, series of clinical isolates have been periodically collected from two patients during chemotherapy with imipenem. The isolates exhibited different levels of resistance towards multiple classes of antibiotics, consistently with the presence or the absence of porins and efflux pumps. Transport assays were used to characterize membrane permeability defects. Simultaneous genome-wide analysis allowed the identification of putative mutations responsible for MDR. The genome of the imipenem-susceptible isolate G7 was sequenced to closure and used as a reference for comparative genomics. This approach uncovered several loci that were specifically mutated in MDR isolates and whose products are known to control membrane permeability. These were omp35 and omp36, encoding the two major porins; rob, encoding a global AraC-type transcriptional activator; cpxA, phoQ and pmrB, encoding sensor kinases of the CpxRA, PhoPQ and PmrAB two-component regulatory systems, respectively. This report provides a comprehensive analysis of membrane alterations relative to mutational steps in the evolution of MDR of a recognized nosocomial pathogen.

Enterobacter aerogenes metabolites enhance Microcystis aeruginosa biomass recovery for sustainable bioflocculant and biohydrogen production.

PubMed

Xu, Liang; Zhou, Mo; Ju, Hanyu; Zhang, Zhenxing; Zhang, Jiquan; Sun, Caiyun

2018-09-01

We report a recycling bioresource involving harvesting of Microcystis aeruginosa using the bioflocculant (MBF-32) produced by Enterobacter aerogenes followed by the recovery of the harvested M. aeruginosa as the main substrate for the sustainable production of MBF-32 and biohydrogen. The experimental results indicate that the efficiency of bioflocculation exceeded 90% under optimal conditions. The harvested M. aeruginosa was further recycled as the main substrate for the supply of necessary elements. The highest yield (3.6±0.1g/L) of MBF-32 could be obtained from 20g/L of wet biomass of M. aeruginosa with an additional 20g/L of glucose as the extra carbon source. The highest yield of biohydrogen was 35mL of H 2 /g (dw) algal biomass, obtained from 20g/L of wet biomass of M. aeruginosa with an additional 10g/L of glycerol. Transcriptome analyses indicated that MBF-32 was mainly composed of polysaccharide and tyrosine/tryptophan proteins. Furthermore, NADH synthase and polysaccharide export-related genes were found to be up-regulated. Copyright © 2018 Elsevier B.V. All rights reserved.

Molecular identification of aiiA homologous gene from endophytic Enterobacter species and in silico analysis of putative tertiary structure of AHL-lactonase.

PubMed

Rajesh, P S; Rai, V Ravishankar

2014-01-03

The aiiA homologous gene known to encode AHL- lactonase enzyme which hydrolyze the N-acylhomoserine lactone (AHL) quorum sensing signaling molecules produced by Gram negative bacteria. In this study, the degradation of AHL molecules was determined by cell-free lysate of endophytic Enterobacter species. The percentage of quorum quenching was confirmed and quantified by HPLC method (p<0.0001). Amplification and sequence BLAST analysis showed the presence of aiiA homologous gene in endophytic Enterobacter asburiae VT65, Enterobacter aerogenes VT66 and Enterobacter ludwigii VT70 strains. Sequence alignment analysis revealed the presence of two zinc binding sites, "HXHXDH" motif as well as tyrosine residue at the position 194. Based on known template available at Swiss-Model, putative tertiary structure of AHL-lactonase was constructed. The result showed that novel endophytic strains of Enterobacter genera encode the novel aiiA homologous gene and its structural importance for future study. Copyright © 2013 Elsevier Inc. All rights reserved.

Risk factors and treatment outcomes of bloodstream infection caused by extended-spectrum cephalosporin-resistant Enterobacter species in adults with cancer.

PubMed

Huh, Kyungmin; Kang, Cheol-In; Kim, Jungok; Cho, Sun Young; Ha, Young Eun; Joo, Eun-Jeong; Chung, Doo Ryeon; Lee, Nam Yong; Peck, Kyong Ran; Song, Jae-Hoon

2014-02-01

Treatment of Enterobacter infection is complicated due to its intrinsic resistance to cephalosporins. Medical records of 192 adults with cancer who had Enterobacter bacteremia were analyzed retrospectively to evaluate the risk factors for and the treatment outcomes in extended-spectrum cephalosporin (ESC)-resistant Enterobacter bacteremia in adults with cancer. The main outcome measure was 30-day mortality. Of the 192 patients, 53 (27.6%) had bloodstream infections caused by ESC-resistant Enterobacter species. Recent use of a third-generation cephalosporin, older age, tumor progression at last evaluation, recent surgery, and nosocomial acquisition were associated with ESC-resistant Enterobacter bacteremia. The 30-day mortality rate was significantly higher in the resistant group. Multivariate analysis showed that respiratory tract infection, tumor progression, septic shock at presentation, Enterobacter aerogenes as the culprit pathogen, and diabetes mellitus were independent risk factors for mortality. ESC resistance was significantly associated with mortality in patients with E. aerogenes bacteremia, although not in the overall patient population. Copyright © 2014 Elsevier Inc. All rights reserved.

The Feasibility of Using Pyrolysis-Mass Spectrometry and Pyrolysis-MS/MS with Pattern Recognition for the Identification of Biological Materials.

DTIC Science & Technology

1987-01-07

Bacillus subtilis (2) (3) Enterobacter aerogenes (3) (3) Providencia alcalifaciens (3) (3) Streptococcus faecalis (0) (3) Streptococcus salivarius (0) (3...licheniformis i 5 10. Enterobacter aerogenes j 5 S 11. Streptococcus lactis k 5 12. Providencia alcalifaciens 1 5 13. Streptococcus faecalis m 5 14. Streptococcus...exclusively. In a study of killing methods, four species of bacteria, P. vulgaris, P. fluorescens, E. coli and E. aerogenes , were each subjected to five

Coexistence of SHV-4- and TEM-24-Producing Enterobacter aerogenes Strains before a Large Outbreak of TEM-24-Producing Strains in a French Hospital

PubMed Central

Mammeri, H.; Laurans, G.; Eveillard, M.; Castelain, S.; Eb, F.

2001-01-01

In 1996, a monitoring program was initiated at the teaching hospital of Amiens, France, and carried out for 3 years. All extended-spectrum β-lactamase (ESBL)-producing Enterobacter aerogenes isolates recovered from clinical specimens were collected for investigation of their epidemiological relatedness by pulsed-field gel electrophoresis and enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) and determination of the type of ESBL harbored by isoelectric focusing and DNA sequencing. Molecular typing revealed the endemic coexistence, during the first 2 years, of two clones expressing, respectively, SHV-4 and TEM-24 ESBLs, while an outbreak of the TEM-24-producing strain raged in the hospital during the third year, causing the infection or colonization of 165 patients. Furthermore, this strain was identified as the prevalent clone responsible for outbreaks in many French hospitals since 1996. This study shows that TEM-24-producing E. aerogenes is an epidemic clone that is well established in the hospital's ecology and able to spread throughout wards. The management of the outbreak at the teaching hospital of Amiens, which included the reinforcement of infection control measures, failed to obtain complete eradication of the clone, which has become an endemic pathogen. PMID:11376055

Assessment of Environmental Effects of Ordnance Compounds and their Transformation Products in Coastal Ecosystems

DTIC Science & Technology

2003-12-01

common sediment bacteria Enterobacter aerogenes, Pseudomonas fluorescens, Escherichia coli, Klebsiella sp. and Aeromonas sp. before and after... Pseudomonas fluorescens, Enterobacter aerogenes, Escherichia coli, Klebsiella sp. and Aeromonas sp. are known important decomposers in sediments and...including some compounds of environmental concern such as substituted azobenzenes or phenazines (Haderlein and Schwarzenbach 1995). Aminonitrotoluenes

Quantifying the effect of hand wash duration, soap use, ground beef debris, and drying methods on the removal of Enterobacter aerogenes on hands.

PubMed

Jensen, Dane A; Danyluk, Michelle D; Harris, Linda J; Schaffner, Donald W

2015-04-01

Hand washing is recognized as a crucial step in preventing foodborne disease transmission by mitigating crosscontamination among hands, surfaces, and foods. This research was undertaken to establish the importance of several keys factors (soap, soil, time, and drying method) in reducing microorganisms during hand washing. A nonpathogenic nalidixic acid-resistant Enterobacter aerogenes surrogate for Salmonella was used to assess the efficacy of using soap or no soap for 5 or 20 s on hands with or without ground beef debris and drying with paper towel or air. Each experiment consisted of 20 replicates, each from a different individual with ∼ 6 log CFU/ml E. aerogenes on their hands. A reduction of 1.0 ± 0.4 and 1.7 ± 0.8 log CFU of E. aerogenes was observed for a 5-s wash with no soap and a 20-s wash with soap, respectively. When there was no debris on the hands, there was no significant difference between washing with and without soap for 20 s (P > 0.05). Likewise, there was no significant difference in the reductions achieved when washing without soap, whether or not debris was on the hands (P > 0.05). A significantly greater reduction (P < 0.05) in E. aerogenes (0.5 log CFU greater reduction) was observed with soap when there was ground beef debris on the hands. The greatest difference (1.1 log CFU greater average reduction) in effectiveness occurred when ground beef debris was on the hands and a 20-s wash with water was compared with a 20-s wash with soap. Significantly greater (P < 0.05) reductions were observed with paper towel drying compared with air (0.5 log CFU greater reductions). Used paper towels may contain high bacterial levels (>4.0 log CFU per towel) when hands are highly contaminated. Our results support future quantitative microbial risk assessments needed to effectively manage risks of foodborne illness in which food workers' hands are a primary cause.

Impairment of NADH dehydrogenase and regulation of anaerobic metabolism by the small RNA RyhB and NadE for improved biohydrogen production in Enterobacter aerogenes.

PubMed

Wu, Yan; Hao, Yaqiao; Wei, Xuan; Shen, Qi; Ding, Xuanwei; Wang, Liyan; Zhao, Hongxin; Lu, Yuan

2017-01-01

Enterobacter aerogenes is a facultative anaerobe and is one of the most widely studied bacterial strains because of its ability to use a variety of substrates, to produce hydrogen at a high rate, and its high growth rate during dark fermentation. However, the rate of hydrogen production has not been optimized. In this present study, three strategies to improve hydrogen production in E. aerogenes , namely the disruption of nuoCDE , overexpression of the small RNA RyhB and of NadE to regulate global anaerobic metabolism, and the redistribution of metabolic flux. The goal of this study was to clarify the effect of nuoCDE , RyhB, and NadE on hydrogen production and how the perturbation of NADH influences the yield of hydrogen gas from E. aerogenes . NADH dehydrogenase activity was impaired by knocking out nuoCD or nuoCDE in E. aerogenes IAM1183 using the CRISPR-Cas9 system to explore the consequent effect on hydrogen production. The hydrogen yields from IAM1183-CD( ∆nuoC / ∆nuoD ) and IAM1183-CDE ( ∆nuoC / ∆nuoD / ∆nuoE ) increased, respectively, by 24.5 and 45.6% in batch culture (100 mL serum bottles). The hydrogen produced via the NADH pathway increased significantly in IAM1183-CDE, suggesting that nuoE plays an important role in regulating NADH concentration in E. aerogenes . Batch-cultivating experiments showed that by the overexpression of NadE (N), the hydrogen yields of IAM1183/N, IAM1183-CD/N, and IAM1183-CDE/N increased 1.06-, 1.35-, and 1.55-folds, respectively, compared with IAM1183. Particularly worth mentioning is that the strain IAM118-CDE/N reached 2.28 mol in H 2 yield, per mole of glucose consumed. IAN1183/R, IAM1183-CD/R, and IAM1183-CDE/R showed increasing H 2 yields in batch culture. Metabolic flux analysis indicated that increased expression of RyhB led to a significant shift in metabolic patterns. We further investigated IAM1183-CDE/N, which had the best hydrogen-producing traits, as a potential candidate for industry applications

Clonality, outer-membrane proteins profile and efflux pump in KPC- producing Enterobacter sp. in Brazil.

PubMed

Rosa, Juliana Ferraz; Rizek, Camila; Marchi, Ana Paula; Guimaraes, Thais; Miranda, Lourdes; Carrilho, Claudia; Levin, Anna S; Costa, Silvia F

2017-03-17

Carbapenems resistance in Enterobacter spp. has increased in the last decade, few studies, however, described the mechanisms of resistance in this bacterium. This study evaluated clonality and mechanisms of carbapenems resistance in clinical isolates of Enterobacter spp. identified in three hospitals in Brazil (Hospital A, B and C) over 7-year. Antibiotics sensitivity, pulsed-field gel electrophoresis (PFGE), PCR for carbapenemase and efflux pump genes were performed for all carbapenems-resistant isolates. Outer-membrane protein (OMP) was evaluated based on PFGE profile. A total of 130 isolates of Enterobacter spp were analyzed, 44/105 (41, 9%) E. aerogenes and 8/25 (32,0%) E. cloacae were resistant to carbapenems. All isolates were susceptible to fosfomycin, polymyxin B and tigecycline. KPC was present in 88.6% of E. aerogenes and in all E. cloacae resistant to carbapenems. The carbapenems-resistant E. aerogenes identified in hospital A belonged to six clones, however, a predominant clone was identified in this hospital over the study period. There is a predominant clone in Hospital B and Hospital C as well. The mechanisms of resistance to carbapenems differ among subtypes. Most of the isolates co-harbored blaKPC, blaTEM and /or blaCTX associated with decreased or lost of 35-36KDa and or 39 KDa OMP. The efflux pump AcrAB-TolC gene was only identified in carbapenems-resistant E. cloacae. There was a predominant clone in each hospital suggesting that cross-transmission of carbapenems-resistant Enterobacter spp. was frequent. The isolates presented multiple mechanisms of resistance to carbapenems including OMP alteration.

Physiological and biochemical role of the butanediol pathway in Aerobacter (Enterobacter) aerogenes.

PubMed Central

Johansen, L; Bryn, K; Stormer, F C

1975-01-01

Aerobacter (Enterobacter) aerogenes wild type and three mutants deficient in the formation of acetoin and 2,3-butanediol were grown in a glucose minimal medium. Culture densities, pH, and diacetyl, acetoin, and 2,3-butanediol levels were recorded. The pH in wild-type cultures dropped from 7.0 to 5.8, remained constant while acetoin and 2,3-butanediol were formed, and increased to pH 6.5 after exhaustion of the carbon source. More 2,3-butanediol than acetoin was formed initially, but after glucose exhaustion reoxidation to acetoin occurred. The three mutants differed from the wild type in yielding acid cultures (pH below 4.5). The wild type and one of the mutants were grown exponentially under aerobic and anaerobic conditions with the pH fixed at 7.0, 5.8, and 5.0, respectively. Growth rates decreased with decreasing pH values. Aerobically, this effect was weak, and the two strains were affected to the same degree. Under anaerobic conditions, the growth rates were markedly inhibited at a low pH, and the mutant was slightly more affected than the wild type. Levels of alcohol dehydrogenase were low under all conditions, indicating that the enzyme plays no role during exponential growth. The levels of diacetyl (acetoin) reductase, lactate dehydrogenase, and phosphotransacetylase were independent of the pH during aerobic growth of the two strains. Under anaerobic conditions, the formation of diacetyl (acetoin) reductase was pH dependent, with much higher levels of the enzyme at pH 5.0 than at pH 7.0. Lactate dehydrogenase and phosphotransacetylase revealed the same pattern of pH-dependent formation in the mutant, but not in the wild type. PMID:239921

Enterobacter aerogenes Hormaeche and Edwards 1960 (Approved Lists 1980) and Klebsiella mobilis Bascomb et al. 1971 (Approved Lists 1980) share the same nomenclatural type (ATCC 13048) on the Approved Lists and are homotypic synonyms, with consequences for the name Klebsiella mobilis Bascomb et al. 1971 (Approved Lists 1980).

PubMed

Tindall, B J; Sutton, G; Garrity, G M

2017-02-01

Enterobacter aerogenes Hormaeche and Edwards 1960 (Approved Lists 1980) and Klebsiella mobilis Bascomb et al. 1971 (Approved Lists 1980) were placed on the Approved Lists of Bacterial Names and were based on the same nomenclatural type, ATCC 13048. Consequently they are to be treated as homotypic synonyms. However, the names of homotypic synonyms at the rank of species normally are based on the same epithet. Examination of the Rules of the International Code of Nomenclature of Bacteria in force at the time indicates that the epithet mobilis in Klebsiella mobilis Bascomb et al. 1971 (Approved Lists 1980) was illegitimate at the time the Approved Lists were published and according to the Rules of the current International Code of Nomenclature of Prokaryotes continues to be illegitimate.

Ram locus is a key regulator to trigger multidrug resistance in Enterobacter aerogenes.

PubMed

Molitor, Alexander; James, Chloë E; Fanning, Séamus; Pagès, Jean-Marie; Davin-Regli, Anne

2018-02-01

Several genetic regulators belonging to AraC family are involved in the emergence of MDR isolates of E. aerogenes due to alterations in membrane permeability. Compared with the genetic regulator Mar, RamA may be more relevant towards the emergence of antibiotic resistance. Focusing on the global regulators, Mar and Ram, we compared the amino acid sequences of the Ram repressor in 59 clinical isolates and laboratory strains of E. aerogenes. Sequence types were associated with their corresponding multi-drug resistance phenotypes and membrane protein expression profiles using MIC and immunoblot assays. Quantitative gene expression analysis of the different regulators and their targets (porins and efflux pump components) were performed. In the majority of the MDR isolates tested, ramR and a region upstream of ramA were mutated but marR or marA were unchanged. Expression and cloning experiments highlighted the involvement of the ram locus in the modification of membrane permeability. Overexpression of RamA lead to decreased porin production and increased expression of efflux pump components, whereas overexpression of RamR had the opposite effects. Mutations or deletions in ramR, leading to the overexpression of RamA predominated in clinical MDR E. aerogenes isolates and were associated with a higher-level of expression of efflux pump components. It was hypothesised that mutations in ramR, and the self-regulating region proximal to ramA, probably altered the binding properties of the RamR repressor; thereby producing the MDR phenotype. Consequently, mutability of RamR may play a key role in predisposing E. aerogenes towards the emergence of a MDR phenotype.

[Cloning of Enterobacter aerogenes fh1A gene and overexpression of hydrogen production].

PubMed

Zhao, Jinfang; Song, Wenlu; Cheng, Jun; Zhang, Chuanxi

2010-06-01

We amplified and overexpressed the FHL activator (fh1A) in E. aerogenes ATCC13408 to enhance hydrogen production. By using universal primers and genome walking, we cloned the full open reading frame (ORF) of fh1A gene. We inserted it into the glutathion S-transferase (GST) fusion expression vector pGEX4T-2-Cat, and transformed the recombinant plasmid into E. aerogenes ATCC13408 via electroporation for expression. Then we measured the hydrogen production of the recombinant strain in a batch culture. We found that the ORF of fh1A was 2073 base pair in length, potential to encode a 690 amino acid peptide (GenBank accession GU188474). The Fh1A protein from E. aerogenes ATCC13408 shared high amino acid identities with those from other bacterial species. By using SDS-PAGE and Western blot analysis, we confirmed that the fh1A gene had successfully expressed in the strain. The hydrogen yield of the recombinant strain was increased from 1.23 to 1.48 mol H2/mol glucose. [ Conclusion ] Enhancement of hydrogen productivity was attained under anaerobic conditions with the recombinant strain.

Phenolic compounds: Strong inhibitors derived from lignocellulosic hydrolysate for 2,3-butanediol production by Enterobacter aerogenes.

PubMed

Lee, Sang Jun; Lee, Ju Hun; Yang, Xiaoguang; Kim, Sung Bong; Lee, Ja Hyun; Yoo, Hah Young; Park, Chulhwan; Kim, Seung Wook

2015-12-01

Lignocellulosic biomass are attractive feedstocks for 2,3-butanediol production due to their abundant supply and low price. During the hydrolysis of lignocellulosic biomass, various byproducts are formed and their effects on 2,3-butanediol production were not sufficiently studied compared to ethanol production. Therefore, the effects of compounds derived from lignocellulosic biomass (weak acids, furan derivatives and phenolics) on the cell growth, the 2,3-butanediol production and the enzymes activity involved in 2,3-butanediol production were evaluated using Enterobacter aerogenes ATCC 29007. The phenolic compounds showed the most toxic effects on cell growth, 2,3-butanediol production and enzyme activity, followed by furan derivatives and weak acids. The significant effects were not observed in the presence of acetic acid and formic acid. Also, feasibility of 2,3-butanediol production from lignocellulosic biomass was evaluated using Miscanthus as a feedstock. In the fermentation of Miscanthus hydrolysate, 11.00 g/L of 2,3-butanediol was obtained from 34.62 g/L of reducing sugar. However, 2,3-butanediol was not produced when the concentration of total phenolic compounds in the hydrolysate increased to more than 1.5 g/L. The present study provides useful information to develop strategies for biological production of 2,3-butanediol and to establish biorefinery for biochemicals from lignocellulosic biomass. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Genetic characterization of an extended-spectrum AmpC cephalosporinase with hydrolysing activity against fourth-generation cephalosporins in a clinical isolate of Enterobacter aerogenes selected in vivo.

PubMed

Rodríguez-Martínez, Jose M; Fernández-Echauri, Pedro; Fernández-Cuenca, Felipe; Diaz de Alba, Paula; Briales, Alejandra; Pascual, Alvaro

2012-01-01

Extended-spectrum AmpC cephalosporinases (ESACs) have been reported in Enterobacteriaceae, Pseudomonas aeruginosa and Acinetobacter baumannii. Here, we characterize a new AmpC variant presenting a broadened substrate activity towards fourth-generation cephalosporins, selected in vivo following cefepime treatment for Enterobacter aerogenes. Two consecutive clonally related isolates of E. aerogenes were evaluated. Screening for ESAC production was performed using plates containing 200 mg/L cloxacillin. MICs were determined by microdilution (CLSI guidelines). bla(AmpC) genes were cloned into a pCR-Blunt II-TOPO vector and expressed in Escherichia coli. The ampC genes were cloned into vector pGEX-6P-1 for protein purification. Isolate Ea595 was resistant to two fourth-generation cephalosporins, cefepime and cefpirome; using plates containing cloxacillin, susceptibility to ceftazidime and cefepime was restored, suggesting overproduction of the ESAC β-lactamase. Sequencing identified a new AmpC β-lactamase variant presenting one amino acid substitution, Val291Gly, inside the H-10 helix. Recombinant plasmids harbouring this ESAC β-lactamase conferred a broadened resistance profile to cefepime and cefpirome, with resistance levels increasing from 16- to 32-fold in E. coli. AmpC-Ea595 hydrolysed ceftazidime, cefepime and cefpirome at high levels, presenting a lower K(m) and enabling us to classify the enzyme as an ESAC. Homology modelling suggested that the size of the active site could have increased. We characterized an ESAC β-lactamase selected in vivo and conferring a high level of resistance to fourth-generation cephalosporins in E. aerogenes. The broadened spectrum was caused by a new modification to the H-10 helix, which modified the active site.

Enterobacter aerogenes Needle Stick Leads to Improved Biological Management System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johanson, Richard E.

2004-08-01

A laboratory worker who received a needle stick from a contaminated needle while working with a culture containing Enterobactor aerogenes developed a laboratory acquired infection. Although this organism has been shown to cause community and nosocomial infections, there have been no documented cases of a laboratory acquired infections. Lessons learned from the event led to corrective actions which included modification of lab procedures, development of a biological inventory tracking and risk identification system and the establishment of an effective biological safety program.

Prevalence and Antibiotic Resistance of Gram-Negative Pathogenic Bacteria Species Isolated from Periplaneta americana and Blattella germanica in Varanasi, India

PubMed Central

Wannigama, D Leshan; Dwivedi, Rishabh; Zahraei-Ramazani, Alireza

2014-01-01

Background Cockroaches are among the medically important pests found within the human habitations that cause serious public health problems. They may harbor a number of pathogenic bacteria on the external surface with antibiotic resistance. Hence, they are regarded as major microbial vectors. This study investigates the prevalence and antibiotic resistance of Gram-negative pathogenic bacteria species isolated from Periplaneta americana and Blattella germanica in Varanasi, India. Methods: Totally, 203 adult cockroaches were collected form 44 households and 52 food-handling establishments by trapping. Bacteriological examination of external surfaces of Pe. americana and Bl. germanica were carried out using standard method and antibiotics susceptibility profiles of the isolates were determined using Kirby-Bauer disc diffusion methods. Results: Among the places, we found that 54% had cockroache infestation in households and 77% in food- handling establishments. There was no significant different between the overall bacteria load of the external surface in Pe. americana (64.04%) and Bl. germanica (35.96%). However the predominant bacteria on cockroaches were Klebsiella pneumonia, Escherichia coli, Enterobacter aerogenes, and Pseudomonas aeruginosa. However, Kl. pneumoniae and Ps. aeruginosa were the most prevalent, drug-resistant strains were isolated from the cockroaches with 100% resistance to sulfamethoxazole/trimethoprim and ampicillin. For individual strains of bacteria, Escherichia coli was found to have multi-resistance to four antibiotic tested, Citrobacter freundii four, Enterobacter aerogenes and Proteus mirabilis to three. Conclusion: Cockroaches are uniformly distributed in domestic environment, which can be a possible vector for transmission of drug-resistant bacteria and food-borne diseases. PMID:25629061

Chemical composition and antibacterial activity of Lavandula coronopifolia essential oil against antibiotic-resistant bacteria.

PubMed

Ait Said, L; Zahlane, K; Ghalbane, I; El Messoussi, S; Romane, A; Cavaleiro, C; Salgueiro, L

2015-01-01

The aim of this study was to analyse the composition of the essential oil (EO) of Lavandula coronopifolia from Morocco and to evaluate its in vitro antibacterial activity against antibiotic-resistant bacteria isolated from clinical infections. The antimicrobial activity was assessed by a broth micro-well dilution method using multiresistant clinical isolates of 11 pathogenic bacteria: Klebsiella pneumoniae subsp. pneumoniae, Klebsiella ornithinolytica, Escherichia coli, Enterobacter cloacae, Enterobacter aerogenes, Providencia rettgeri, Citrobacter freundii, Hafnia alvei, Salmonella spp., Acinetobacter baumannii and methicillin-resistant Staphylococcus aureus. The main compounds of the oil were carvacrol (48.9%), E-caryophyllene (10.8%) and caryophyllene oxide (7.7%). The oil showed activity against all tested strains with minimal inhibitory concentration (MIC) values ranging between 1% and 4%. For most of the strains, the MIC value was equivalent to the minimal bactericidal concentration value, indicating a clear bactericidal effect of L. coronopifolia EO.

Disruption of lactate dehydrogenase and alcohol dehydrogenase for increased hydrogen production and its effect on metabolic flux in Enterobacter aerogenes.

PubMed

Zhao, Hongxin; Lu, Yuan; Wang, Liyan; Zhang, Chong; Yang, Cheng; Xing, Xinhui

2015-10-01

Hydrogen production by Enterobacter aerogenes from glucose was enhanced by deleting the targeted ldhA and adh genes responsible for two NADH-consuming pathways which consume most NADH generated from glycolysis. Compared with the wild-type, the hydrogen yield of IAM1183-ΔldhA increased 1.5 fold. Metabolic flux analysis showed both IAM1183-ΔldhA and IAM1183-Δadh exhibited significant changes in flux, including enhanced flux towards the hydrogen generation. The lactate production of IAM1183-ΔldhA significantly decreased by 91.42%, while the alcohol yield of IAM1183-Δadh decreased to 30%. The mutant IAM1183-ΔldhA with better hydrogen-producing performance was selected for further investigation in a 5-L fermentor. The hydrogen production of IAM1183-ΔldhA was 2.3 times higher than the wild-type. Further results from the fermentation process showed that the pH decreased to 5.39 levels, then gradually increased to 5.96, indicating that some acidic metabolites might be degraded or uptaken by cells. Copyright © 2015 Elsevier Ltd. All rights reserved.

NDM-1 encoded by a pNDM-BJ01-like plasmid p3SP-NDM in clinical Enterobacter aerogenes

PubMed Central

Chen, Zhenhong; Li, Hongxia; Feng, Jiao; Li, Yuxue; Chen, Xin; Guo, Xuemin; Chen, Weijun; Wang, Li; Lin, Lei; Yang, Huiying; Yang, Wenhui; Wang, Jie; Zhou, Dongsheng; Liu, Changting; Yin, Zhe

2015-01-01

A carbapenem-nonsusceptible Enterobacter aerogenes strain named 3-SP was isolated from a human case of pneumonia in a Chinese teaching hospital. NDM-1 carbapenemase is produced by a pNDM-BJ01-like conjugative plasmid designated p3SP-NDM to account for carbapenem resistance of 3-SP. p3SP-NDM was fully sequenced and compared with all publically available pNDM-BJ01-like plasmids. The genetic differences between p3SP-NDM and pNDM-BJ01 include only 18 single nucleotide polymorphisms, a 1 bp deletion and a 706 bp deletion. p3SP-NDM and pNDM-BJ01 harbor an identical Tn125 element organized as ISAba125, blaNDM−1, bleMBL, ΔtrpF, dsbC, cutA, ΔgroES, groEL, ISCR27, and ISAba125. The blaNDM−1 surrounding regions in these pNDM-BJ01-like plasmids have a conserved linear organization ISAba14-aphA6-Tn125-unknown IS, with considerable genetic differences identified within or immediately downstream of Tn125. All reported pNDM-BJ01-like plasmids are exclusively found in Acinetobacter, whereas this is the first report of identification of a pNDM-BJ01-like plasmid in Enterobacteriaceae. PMID:25926823

NDM-1 encoded by a pNDM-BJ01-like plasmid p3SP-NDM in clinical Enterobacter aerogenes.

PubMed

Chen, Zhenhong; Li, Hongxia; Feng, Jiao; Li, Yuxue; Chen, Xin; Guo, Xuemin; Chen, Weijun; Wang, Li; Lin, Lei; Yang, Huiying; Yang, Wenhui; Wang, Jie; Zhou, Dongsheng; Liu, Changting; Yin, Zhe

2015-01-01

A carbapenem-nonsusceptible Enterobacter aerogenes strain named 3-SP was isolated from a human case of pneumonia in a Chinese teaching hospital. NDM-1 carbapenemase is produced by a pNDM-BJ01-like conjugative plasmid designated p3SP-NDM to account for carbapenem resistance of 3-SP. p3SP-NDM was fully sequenced and compared with all publically available pNDM-BJ01-like plasmids. The genetic differences between p3SP-NDM and pNDM-BJ01 include only 18 single nucleotide polymorphisms, a 1 bp deletion and a 706 bp deletion. p3SP-NDM and pNDM-BJ01 harbor an identical Tn125 element organized as ISAba125, bla NDM-1, ble MBL, ΔtrpF, dsbC, cutA, ΔgroES, groEL, ISCR27, and ISAba125. The bla NDM-1 surrounding regions in these pNDM-BJ01-like plasmids have a conserved linear organization ISAba14-aphA6-Tn125-unknown IS, with considerable genetic differences identified within or immediately downstream of Tn125. All reported pNDM-BJ01-like plasmids are exclusively found in Acinetobacter, whereas this is the first report of identification of a pNDM-BJ01-like plasmid in Enterobacteriaceae.

Detection of New Delhi Metallo-β-Lactamase Variants NDM-4, NDM-5, and NDM-7 in Enterobacter aerogenes Isolated from a Neonatal Intensive Care Unit of a North India Hospital: A First Report.

PubMed

Ahmad, Nayeem; Ali, Syed Manazir; Khan, Asad U

2018-03-01

A total 402 Enterobacteriaceae isolates were recovered from blood and rectal swabs of 1,000 infants admitted to the Neonatal Intensive Care Unit (NICU) of the Jawaharlal Medical College and Hospital Aligarh, India. Carbapenamase producers were determined by Carba NP phenotype biochemical assay. Out of 402 isolates, it was the first time three of the isolates were identified as Enterobacter aerogenes carrying bla NDM-4, bla NDM-5, and bla NDM-7 genes. These genes were identified by polymerase chain reaction (PCR) and sequence analysis. The isolates were further characterized to know the plasmid type and genetic environment features, including integron and IS elements. All the three E. aerogenes isolates (AK-93, AK-95, and AK-96) were resistant to all β-lactams, including carbapenems. The β-lactamase genes bla OXA-1 , bla OXA-9, bla SHV-1 , and bla VIM-2 were also found to be coassociated with bla NDM-4 in AK-93, bla OXA-1 , bla OXA-9, and bla CMY-149 were found to be coexisted with bla NDM-5 in AK-95, and bla OXA-1; bla OXA-9, and bla CMY-145 were also found to be coassociated with bla NDM-7 in AK-96, identified by PCR analysis. Plasmid-based replicon typing revealed plasmids of different incompatibility in E. aerogenes in each of the isolates, AK-93 AK-95, and AK-96, respectively. ERIC-PCR was performed for the analysis of genetic relatedness of the strains. We found bla NDM-4 , bla NDM-5, and bla NDM-7 producing three E. aerogenes strains, which were not clonally related. Genetic environment analysis revealed the presence of bleomycin resistance gene (ble MBL ) to downstream of bla NDM and complete ISAba125 sequence were found upstream of bla NDM in all the three variants of these isolates. This is the first time we have identified bla NDM-4 , bla NDM-5, and bla NDM-7 in E. aerogenes species, isolated from the NICU of a tertiary care hospital in India.

Identification of Human Intestinal Bacteria that Promote or Inhibit Inflammation

DTIC Science & Technology

2012-11-01

Lactobacillus "acidophilus" Lactobacillus " plantarum " ProvidenCa"sp." Enterobacter"aerogenes" Lactobacillus "paraalimentarius" Salmonella"typhi...8217 indica3ve’of’the’poten3al’of’these’microbes’to’induce’intes3nal’inflamma3on.’ 0" 5" 10" 15" 20" 25" 30" 35" 40" 45" 50" no"bacteria" Lactobacillus "brevis" Escherichea"coli"(DH5a)" Klebsiella"pneumonia" Salmonella...only

Epidemiology and molecular characterization of extended-spectrum beta-lactamase-producing Enterobacter spp., Pantoea agglomerans, and Serratia marcescens isolates from a Bulgarian hospital.

PubMed

Markovska, Rumyana Donkova; Stoeva, Temenuga Jekova; Bojkova, Kalina Dineva; Mitov, Ivan Gergov

2014-04-01

Forty-two extended-spectrum beta-lactamase (ESBL)-producing isolates of Enterobacter aerogenes, Enterobacter cloacae, Pantoea agglomerans, and Serratia marcescens, collected consecutively during the period January-November 2011 from the University Hospital in Varna, Bulgaria, were studied to characterize their ESBLs by isoelectric focusing, group-specific PCR, and sequencing. The epidemiological relationship was evaluated by random amplified polymorphic DNA analysis (RAPD). Transferability of ESBL genes was determined by conjugation experiments. Plasmid analysis was done by replicon typing and PstI fingerprinting. The overall rate of ESBL production was 20%. The most widespread enzyme was CTX-M-3, found in 64%. It was dominant in E. aerogenes (100%) and S. marcescens (83%). SHV-12, CTX-M-3, and CTX-M-15 were found among E. cloacae isolates in 50%, 35%, and 45%, respectively. Three main CTX-M-3-producing epidemic clones of E. aerogenes and S. marcescens have been detected. Among E. cloacae isolates, six different RAPD profiles were discerned. The plasmids harboring blaCTX-M-3 belonged to IncL/M type and demonstrated similar PstI fingerprinting profiles. IncFII plasmids were detected in two CTX-M-15-producing E. cloacae isolates. Our results demonstrate wide intrahospital dissemination of clonal E. aerogenes and S. marcescens isolates, carrying IncL/M conjugative plasmids.

FIRST REPORT OF METALLO-β-LACTAMASES PRODUCING Enterobacter spp. STRAINS FROM VENEZUELA

PubMed Central

Martínez, Dianny; Rodulfo, Hectorina E.; Rodríguez, Lucy; Caña, Luisa E.; Medina, Belkis; Guzman, Militza; Carreño, Numirin; Marcano, Daniel; Donato, Marcos De

2014-01-01

Clinical strains of Enterobacter were isolated from Cumana's Central Hospital in Venezuela, and classified as E. cloacae (21), E. aerogenes (7), E. intermedium (1), E. sakazakii (1) and three unclassified. The strains showed high levels of resistance, especially to SXT (58.1%), CRO (48.8%), CAZ (46.6%), PIP (46.4%), CIP (45.2%) and ATM (43.3%). This is the first report for South America of bla VIM-2 in two E. cloacae and one Enterobacter sp., which also showed multiple mechanisms of resistance. Both E. cloacae showed bla TEM-1, but only one showed bla CTX-M-15 gene, while no bla SHV was detected. PMID:24553611

Isolation, Characterisation and Antagonistic Activity of Bacteria Symbionts Hardcoral Pavona sp. Isolated from Panjang Island, Jepara Against Infectious Multi-drug Resistant (MDR) Bacteria

NASA Astrophysics Data System (ADS)

Ayuningrum, D.; Kristiana, R.; Asagabaldan, M. A.; Sabdono, A.; Radjasa, O. K.; Nuryadi, H.; Trianto, A.

2017-02-01

Pavona sp. is highly spread over Indonesian waters including Panjang Island. Several studies showed that bacteria symbionts hardcoral were the big source of antibiotic product, but there was limited research of the bacteria symbionts with hardcoral Pavona sp. In this research bacteria symbionts from hardcoral Pavona sp. had been collected from Panjang Island, Jepara. Marine bacteria symbionts were isolated by serial dillution method, while antibacterial activity was performed by using overlay and agar block method. The total of 2 from 5 isolates were active to MDR bacteria such as Enterobacter aerogenes and Acinetobacter baumanii, the code were PHC 44/04 and PHC 44/05. Then both of them were identified by morphological and molecular DNA characterization using 16 S rRNA gene sequence. The result of 16 S rRNA identification shows PHC 44/04 has 99% similarities with Virgibacillus salarius strain sa-Vb 1, while PHC 44/05 shows 99% similarities with Pseudoalteromonas flavipulchra strain NCIMB 2033.

Intestinal bacteria in bioaerosols and factors affecting their survival in two oxidation ditch process municipal wastewater treatment plants located in different regions.

PubMed

Wang, Yanjie; Li, Lin; Han, Yunping; Liu, Junxin; Yang, Kaixiong

2018-06-15

Samples from two oxidation ditch process municipal wastewater treatment plants (MWTPs) (HJK and GXQ) in two regions of China were analysed for bacteria, particles, total organic carbon, and water-soluble ions in bioaerosols. Diversity and potential pathogen populations were evaluated by high-throughput sequencing. Bioaerosol sources, factors affecting intestinal bacterial survival, and the relationship between bioaerosols and water were analysed by Source tracker and partial least squares-discriminant, principal component, and canonical correspondence analyses. Culturable bacteria concentrations were 110-846 and 27-579 CFU/m 3 at HJK and GXQ, respectively. Intestinal bacteria constituted 6-33% of bacteria. Biochemical reaction tank, sludge dewatering house (SDH), and fine screen samples showed the greatest contribution to bioaerosol contamination. Enterobacter aerogenes was the main intestinal bacteria (> 99.5%) in HJK and detected at each sampling site. Enterobacter aerogenes (98.67% in SDH), Aeromonas sp. (76.3% in biochemical reaction tank), and Acinetobacter baumannii (99.89% in fine screens) were the main intestinal bacteria in GXQ. Total suspended particulate masses in SDH were 229.46 and 141.6 μg/m 3 in HJK and GXQ, respectively. Percentages of insoluble compounds in total suspended particulates decreased as height increased. The main soluble ions in bioaerosols were Ca 2+ , Na + , Cl - , and SO 4 2- , which ranged from 3.8 to 27.55 μg/m 3 in the MWTPs. Water was a main source of intestinal bacteria in bioaerosols from the MWTPs. Bioaerosols in HJK but not in GXQ were closely related. Relative humidity and some ions positively influenced intestinal bacteria in bioaerosols, while wind speed and solar illumination had a negative influence. Copyright © 2018 Elsevier Inc. All rights reserved.

Occurrence and analysis of irp2 virulence gene in isolates of Klebsiella pneumoniae and Enterobacter spp. from microbiota and hospital and community-acquired infections.

PubMed

Souza Lopes, Ana Catarina; Rodrigues, Juliana Falcão; Cabral, Adriane Borges; da Silva, Maíra Espíndola; Leal, Nilma Cintra; da Silveira, Vera Magalhães; de Morais Júnior, Marcos Antônio

2016-07-01

Eighty-five isolates of Klebsiella pneumoniae and Enterobacter spp., originating from hospital- and community-acquired infections and from oropharyngeal and faecal microbiota from patients in Recife-PE, Brazil, were analyzed regarding the presence of irp2 gene. This is a Yersinia typical gene involved in the synthesis of siderophore yersiniabactin. DNA sequencing confirmed the identity of irp2 gene in five K. pneumoniae, five Enterobacter aerogenes and one Enterobacter amnigenus isolates. To our knowledge in the current literature, this is the first report of the irp2 gene in E. amnigenus, a species considered an unusual human pathogen, and in K. pneumoniae and E. aerogenes isolates from the normal microbiota and from community infections, respectively. Additionally, the analyses of nucleotide and amino acid sequences suggest the irp2 genes derived from isolates used in this study are more closely related to that of Yersinia pestis P.CE882 than to that of Yersinia enterocolitica 8081. These data demonstrated that K. pneumoniae and Enterobacter spp. from normal microbiota and from community- and hospital-acquired infections possess virulence factors important for the establishment of extra-intestinal infections. Copyright © 2016 Elsevier Ltd. All rights reserved.

Digestion of rice straw and oil palm fronds by microflora from rumen and termite bacteria, in vitro.

PubMed

Ramin, M; Alimon, A R; Panandam, J M; Sijam, K; Javanmard, A; Abdullah, N

2008-02-15

The digestion and Volatile Fatty Acid (VFA) production from rice straw and oil palm fronds by cellulolytic bacteria isolated from the termite Coptotermes curvignathus were investigated. The bacteria were Acinetobacter strain Raminalimon, Enterobacter aerogenes strain Razmin C, Enterobacter cloacae strain Razmin B, Bacillus cereus strain Razmin A and Chryseobacterium kwangyangense strain Cb. Acinetobacter strain Raminalimon is an aerobic bacterium, while the other species are facultative anaerobes. There were significant differences (p<0.05) among the bacteria for Dry Matter (DM) lost and acetic acid production from rice straw and Acinetobacter strain Raminalimon showed the highest activity. The facultative bacteria C. kwangyangense strain Cb (cfu mL(-1) 231 x 10(-6), OD: 0.5), E. cloacae (cfu mL(-1) 68 x 10(-7), OD: 0.5) and E. aerogenes (cfu mL(-1) 33 x 10(-7), OD: 0.5) were used for digestion study with the rumen fluid microflora. The in vitro gas production technique was applied for the comparative study and the parameters measured were pH, gas (volume), dry matter lost, acetic acid, propionic acid and butyric acid concentrations. pH was not significantly (p<0.05) different among the five treatments. The bacterium C. kwangyangense strain Cb showed the highest activity (p<0.05) for DM lost, acetic acid, propionic acid and butyric acid production from rice straw when compared to the other bacterial activities. There was no significance (p<0.05) difference between the three bacteria for the dry matter lost of oil palm fronds but the production of Volatile Fatty Acids (VFA) was significantly (p<0.05) high in the treatment which was inoculated with C. kwangyangense strain Cb. The Gen Bank NCBI/EMBL accession numbers for the bacterial strains are EU332791, EU305608, EU305609, EU294508 and EU169201.

Alleviation of phytotoxic effects of cadmium on rice seedlings by cadmium resistant PGPR strain Enterobacter aerogenes MCC 3092.

PubMed

Pramanik, Krishnendu; Mitra, Soumik; Sarkar, Anumita; Maiti, Tushar Kanti

2018-06-05

Heavy metal resistant PGPR mediated bioremediation, phytostimulation and stress alleviation is an eco-friendly method for sustainable agriculture in the metal contaminated soil. The isolation of such PGPR is highly demanding to reduce heavy metals in contaminated cultivated fields for agricultural benefit. The present study was successful to isolate a potent multi-heavy metal resistant PGPR strain, identified as Enterobacter aerogenes strain K6 based on MALDI-TOF MS, FAME analysis and 16S rDNA sequence homology, from rice rhizosphere contaminated with a variety of heavy metals/metalloid near industrial area. The strain exhibited high degree of resistance to Cd 2+ , Pb 2+ and As 3+ upto 4000 μg/mL, 3800 μg/mL and 1500 μg/mL respectively. Intracellular Cd accumulation of this strain was evidenced by AAS-SEM-TEM-EDX-XRF studies. Moreover, it showed several important PGP traits like IAA production, nitrogen fixation, phosphate solubilization, ACC deaminase activity even under high Cd stress (upto 3000 μg/mL). The combined effect of Cd resistance and PGP activities of this strain was manifested to the significant (p < 0.05) growth promotion of rice seedling under Cd stress by reducing oxidative stress (through antioxidants), stress ethylene and Cd uptake in seedlings. Thus K6 strain conferred Cd-tolerance in rice seedlings and could be applied as PGPR in contaminated fields. Copyright © 2018 Elsevier B.V. All rights reserved.

Mutational analysis of the hyc-operon determining the relationship between hydrogenase-3 and NADH pathway in Enterobacter aerogenes.

PubMed

Pi, Jian; Jawed, Muhammad; Wang, Jun; Xu, Li; Yan, Yunjun

2016-01-01

In this study, the hydrogenase-3 gene cluster (hycDEFGH) was isolated and identified from Enterobacter aerogenes CCTCC AB91102. All gene products were highly homologous to the reported bacterial hydrogenase-3 (Hyd-3) proteins. The genes hycE, hycF, hycG encoding the subunits of hydrogenase-3 were targeted for genetic knockout to inhibit the FHL hydrogen production pathway via the Red recombination system, generating three mutant strains AB91102-E (ΔhycE), AB91102-F (ΔhycF) and AB91102-G (ΔhycG). Deletion of the three genes affected the integrity of hydrogenase-3. The hydrogen production experiments with the mutant strains showed that no hydrogen was detected compared with the wild type (0.886 mol/mol glucose), demonstrating that knocking out any of the three genes could inhibit NADH hydrogen production pathway. Meanwhile, the metabolites of the mutant strains were significantly changed in comparison with the wild type, indicating corresponding changes in metabolic flux by mutation. Additionally, the activity of NADH-mediated hydrogenase was found to be nil in the mutant strains. The chemostat experiments showed that the NADH/NAD(+) ratio of the mutant strains increased nearly 1.4-fold compared with the wild type. The NADH-mediated hydrogenase activity and NADH/NAD(+) ratio analysis both suggested that NADH pathway required the involvement of the electron transport chain of hydrogenase-3. Copyright © 2015 Elsevier Inc. All rights reserved.

Malonate-bound structure of the glycerophosphodiesterase from Enterobacter aerogenes (GpdQ) and characterization of the native Fe[superscript 2+] metal-ion preference

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jackson, Colin J.; Hadler, Kieran S.; Carr, Paul D.

2011-09-28

The structure of a malonate-bound form of the glycerophosphodiesterase from Enterobacter aerogenes, GpdQ, has been refined at a resolution of 2.2 {angstrom} to a final R factor of 17.1%. The structure was originally solved to 2.9 {angstrom} resolution using SAD phases from Zn{sup 2+} metal ions introduced into the active site of the apoenzyme [Jackson et al. (2007), J. Mol. Biol. 367, 1047-1062]. However, the 2.9 {angstrom} resolution was insufficient to discern significant details of the architecture of the binuclear metal centre that constitutes the active site. Furthermore, kinetic analysis revealed that the enzyme lost a significant amount of activitymore » in the presence of Zn2+, suggesting that it is unlikely to be a catalytically relevant metal ion. In this communication, a higher resolution structure of GpdQ is presented in which malonate is visibly coordinated in the active site and analysis of the native metal-ion preference is presented using atomic absorption spectroscopy and anomalous scattering. Catalytic implications of the structure and its Fe{sup 2+} metal-ion preference are discussed.« less

Malonate-bound structure of the glycerophosphodiesterase from Enterobacter aerogenes (GpdQ) and characterization of the native Fe[supscript 2+] metal-ion preference

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jackson, Colin J.; Hadler, Kieran S.; Carr, Paul D.

2010-09-20

The structure of a malonate-bound form of the glycerophosphodiesterase from Enterobacter aerogenes, GpdQ, has been refined at a resolution of 2.2 {angstrom} to a final R factor of 17.1%. The structure was originally solved to 2.9 {angstrom} resolution using SAD phases from Zn{sup 2+} metal ions introduced into the active site of the apoenzyme [Jackson et al. (2007), J. Mol. Biol. 367, 1047-1062]. However, the 2.9 {angstrom} resolution was insufficient to discern significant details of the architecture of the binuclear metal centre that constitutes the active site. Furthermore, kinetic analysis revealed that the enzyme lost a significant amount of activitymore » in the presence of Zn{sup 2+}, suggesting that it is unlikely to be a catalytically relevant metal ion. In this communication, a higher resolution structure of GpdQ is presented in which malonate is visibly coordinated in the active site and analysis of the native metal-ion preference is presented using atomic absorption spectroscopy and anomalous scattering. Catalytic implications of the structure and its Fe{sup 2+} metal-ion preference are discussed.« less

Biosurfactant-enhanced hydrogen production from organic fraction of municipal solid waste using co-culture of E. coli and Enterobacter aerogenes.

PubMed

Sharma, Preeti; Melkania, Uma

2017-11-01

The effect of biosurfactants (surfactin and saponin) on the hydrogen production from organic fraction of municipal solid waste (OFMSW) was investigated using co-culture of facultative anaerobes Enterobacter aerogenes and E. coli. The biosurfactants were applied in the concentration ranges of 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5 and 5.0% each. Cumulative hydrogen production (P), maximum hydrogen production rate (Rmax) and lag phases (λ) were analyzed using modified Gompertz model. Results revealed that both the biosurfactants were effective in hydrogen production enhancement. The maximum cumulative hydrogen production of 743.5±14.4ml and 675.6±12.1ml and volumetric hydrogen production of 2.12L H2 /L substrate and 1.93L H2 /L substrate was recorded at 3.5% surfactin and 3.0% saponin respectively. Corresponding highest hydrogen yields were 79.2mlH 2 /gCarbo initial and 72.0mlH 2 /gCarbo initial respectively. Lag phase decreased from 12.5±2.0h at control to a minimum of 9.0±2.8h and 9.5±2.1h at 3.5% surfactin and 3.0% saponin respectively. Volatile fatty acid generation was increased with biosurfactants addition. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Phenotypic and genotypic characterization of resistance to third-generation cephalosporins in Enterobacter spp].

PubMed

Bertona, E; Radice, M; Rodríguez, C H; Barberis, C; Vay, C; Famiglietti, A; Gutkind, G

2005-01-01

Enterobacter spp. are becoming increasingly frequent nosocomial pathogens with multiple resistance mechanism to beta-lactam antibiotics. We carried out the phenotypic and genotypic characterization of beta-lactamases in 27 Enterobacter spp. (25 Enterobacter cloacae y 2 Enterobacter aerogenes), as well as the ability of different extended spectrum-lactamase (ESBL) screening methods. Resistance to third generation cephalosporins was observed in 15/27 (63%) isolates. Twelve resistant isolates produced high level chromosomal encoded AmpC beta-lactamase; 6 of them were also producers of PER-2. Resistance to third generation cephalosporins in the remaining 3 isolates was due to the presence of ESBLs, PER-2 in 2 cases, and CTX-M-2 in the other. Only CTX-M-2 production was detected with all tested cephalosporins using difusion synergy tests, while cefepime improved ESBLs detection in 7/8 PER-2 producers, 4/8 in the inhibitor approximation test and 7/8 with double disk test using cefepime containing disk with and without clavulanic acid. Dilution method, including cephalosporins with and without the inhibitor detected 1/9 ESBLs producers.

Phagocytic and chemiluminescent responses of mouse peritoneal macrophages to living and killed Salmonella typhimurium and other bacteria

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tomita, T.; Blumenstock, E.; Kanegasaki, S.

1981-06-01

In the presence of luminol, resident as well as thioglycolate-induced and immunized macrophages emitted chemiluminescence more efficiently when the cells were exposed to living Salmonella typhimurium than when they were exposed to the same bacterium killed by ultraviolet light or heat. This phenomenon was observed whether or not the bacterium was opsonized. The different response to living and killed bacteria was also found with Escherichia coli, Pseudomonas aeruginosa, Proteus morganii, and Enterobacter aerogenes, but not with Shigella sonnei, Klebsiella pneumoniae, and Propionibacterium acnes. The results suggest that macrophages respond better to living, motile bacteria than to nonmotile or killed bacteria.more » The experimental results obtained with motility mutants of S. typhimurium, E. coli, and P. aeruginosa confirm that macrophages exposed to the motile bacteria emit chemiluminescence more efficiently and ingest the motile bacteria at a much faster rate than the nonmotile bacteria.« less

Heat resistance of histamine-producing bacteria in irradiated tuna loins.

PubMed

Enache, Elena; Kataoka, Ai; Black, D Glenn; Weddig, Lisa; Hayman, Melinda; Bjornsdottir-Butler, Kristin

2013-09-01

Consumption of foods high in biogenic amines leads to an illness known as histamine, or scombrotoxin, poisoning. The illness is commonly associated with consumption of fish with high levels of histamine ( $ 500 ppm). The objective of this study was to determine and compare the heat resistance of five histamine-producing bacteria in irradiated albacore tuna loins. Heat-resistance parameters (D- and z-values) were determined for Morganella morganii, Raoultella planticola, Hafnia alvei, and Enterobacter aerogenes. D- or z-values were not determined for Photobacterium damselae, which was the most heat-sensitive organism in this study. P. damselae declined > 5.9 log CFU/g after a heat treatment of 50°C for 10 min, 54°C for 3 min, and 56°C for 0.5 min. M. morganii was the most heat-resistant histamine-producing bacteria in albacore tuna loins, followed by E. aerogenes, H. alvei, and R. planticola. M. morganii and E. aerogenes had the highest D(50°C), 49.7 ± 17.57 and 51.8 ± 17.38 min, respectively. In addition, M. morganii had the highest D-values for all other temperatures (54, 56, and 58°C) tested. D- and zvalues were also determined for M. morganii in skipjack tuna. While no significant (P > 0.05) difference was observed between D(54°C) and D(56°C) of M. morganii in either albacore or skipjack tuna, the D(58°C) (0.4 ± 0.17 min) was significantly lower (P < 0.05) in skipjack than in albacore (0.9 ± 0.24 min). The z-values for all organisms tested were in the range of 3.2 to 3.8°C. This study suggests that heat treatment designed to control M. morganii in tuna loins is sufficient for controlling histamine-producing bacteria in canned-tuna processing environments.

Impact of furan derivatives and phenolic compounds on hydrogen production from organic fraction of municipal solid waste using co-culture of Enterobacter aerogenes and E. coli.

PubMed

Sharma, Preeti; Melkania, Uma

2017-09-01

In the present study, the effect of furan derivatives (furfural and 5-hydroxymethylfurfural) and phenolic compounds (vanillin and syringaldehyde) on hydrogen production from organic fraction of municipal solid waste (OFMSW) was investigated using co-culture of facultative anaerobes Enterobacter aerogenes and E. coli. The inhibitors were applied in the concentration ranges of 0.25, 0.5, 1, 2 and 5g/L each. Inhibition coefficients of phenolic compounds were higher than those of furan derivatives and vanillin exhibited maximum inhibition coefficients correspondingly lowest hydrogen yield among all inhibitors. Furfural and 5-hydroxymethylfurfural addition resulted in an average decrease of 26.99% and 37.16% in hydrogen yield respectively, while vanillin and syringaldehyde resulted in 49.40% and 42.26% average decrease in hydrogen yield respectively. Further analysis revealed that Furfural and 5-hydroxymethylfurfural were completely degraded up to concentrations of 1g/L, while vanillin and syringaldehyde were degraded completely up to the concentration of 0.5g/L. Volatile fatty acid generation decreased with inhibitors addition. Copyright © 2017 Elsevier Ltd. All rights reserved.

A biological method for in-situ synthesis of hydroxyapatite-coated magnetite nanoparticles using Enterobacter aerogenes: Characterization and acute toxicity assessments.

PubMed

Ahmadzadeh, Elham; Talebnia Rowshan, Farid; Hosseini, Morteza

2017-04-01

Hydroxyapatite (HA)-coated magnetite nanoparticles (MNPs) are being widely investigated for various applications in medical engineering and wastewater treatment. In this work, the MNPs were thoroughly coated by bacterial synthesized HA nanoparticles during biomineralization process using Enterobacter aerogenes. The resulting bacterial-induced precipitate was then calcined at 600°C and investigated with respect to structural characteristics, particle size and magnetic strength by XRD, FT-IR, SEM, EDS, TEM and VSM analyses. The effects of MNPs and HA-coated MNPs (HA-MNPs) on the viability of human MCF-7 cell lines were also investigated via mitochondrial activity test (MTT) and lactate dehydrogenase (LDH) assays. The powder characterization results showed appropriate structural properties for HA-MNPs samples. The particles diameter size of the MNPs and HA-MNPs were in the range of 3-25nm and 20-80nm, respectively. The biologically-synthesized HA-MNPs formed a stable suspension in water while keeping their magnetic property. The saturation magnetization (Ms) of HA-MNPs was measured at ~10emug -1 which was in good agreement with the structural composition of this sample. Finally, the results of the cell lines viability indicated that coating of toxic MNPs via biomineralization was a promising approach in order to synthesize bio-compatible magnetic nanoparticles with suitable physical and chemical structural characteristics. The toxicity level of MNPs was reduced by 10 fold when coated by bacterial-synthesized HA. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of Eliminating Pyruvate Node Pathways and of Coexpression of Heterogeneous Carboxylation Enzymes on Succinate Production by Enterobacter aerogenes

PubMed Central

Yamamoto, Yoko; Fukui, Keita; Nishio, Yousuke; Hashiguchi, Kenichi; Usuda, Yoshihiro; Sode, Koji

2014-01-01

Lowering the pH in bacterium-based succinate fermentation is considered a feasible approach to reduce total production costs. Newly isolated Enterobacter aerogenes strain AJ110637, a rapid carbon source assimilator under weakly acidic (pH 5.0) conditions, was selected as a platform for succinate production. Our previous work showed that the ΔadhE/PCK strain, developed from AJ110637 with inactivated ethanol dehydrogenase and introduced Actinobacillus succinogenes phosphoenolpyruvate carboxykinase (PCK), generated succinate as a major product of anaerobic mixed-acid fermentation from glucose under weakly acidic conditions (pH <6.2). To further improve the production of succinate by the ΔadhE/PCK strain, metabolically engineered strains were designed based on the elimination of pathways that produced undesirable products and the introduction of two carboxylation pathways from phosphoenolpyruvate and pyruvate to oxaloacetate. The highest production of succinate was observed with strain ES04/PCK+PYC, which had inactivated ethanol, lactate, acetate, and 2,3-butanediol pathways and coexpressed PCK and Corynebacterium glutamicum pyruvate carboxylase (PYC). This strain produced succinate from glucose with over 70% yield (gram per gram) without any measurable formation of ethanol, lactate, or 2,3-butanediol under weakly acidic conditions. The impact of lowering the pH from 7.0 to 5.5 on succinate production in this strain was evaluated under pH-controlled batch culture conditions and showed that the lower pH decreased the succinate titer but increased its yield. These findings can be applied to identify additional engineering targets to increase succinate production. PMID:25416770

High prevalence of non-clonal imipenem-nonsusceptible Enterobacter spp. isolates in Korea and their association with porin down-regulation.

PubMed

Lee, Ji-Young; Hong, Yoon-Kyoung; Lee, Haejeong; Ko, Kwan Soo

2017-01-01

We investigated the prevalence and clonal distribution of imipenem-nonsusceptible Enterobacter clinical isolates from hospitals in Korea and the contributions of various mechanisms to imipenem nonsusceptibility. The in vitro antimicrobial susceptibility to imipenem of 357 non-duplicated Enterobacter isolates obtained from eight geographically distant tertiary care hospitals in Korea was evaluated. Imipenem-nonsusceptible Enterobacter isolates were genotyped. Additionally, β-lactamase genes were screened using PCR, and the expression of efflux pump and porin genes was investigated using quantitative RT-PCR. A total of 31 isolates (8.7%) were not susceptible to imipenem. Clonal diversity of 17 imipenem-nonsusceptible E. cloacae isolates was demonstrated by multilocus sequence typing. Fourteen imipenem-nonsusceptible E. aerogenes isolates were found to be distantly genetically related by an ERIC-PCR analysis. Expression levels of porin ompD and ompK35 genes were decreased in all imipenem-nonsusceptible E. cloacae and E. aerogenes isolates. However, only two isolates were found positive for bla IMP and bla VIM genes, and expression of the efflux pump gene, acrB, was not associated with reduced imipenem susceptibility. Imipenem resistance seems to have occurred independently in most of the imipenem-nonsusceptible isolates in this study, and decreased porin expression was found to be the main mechanism underlying this reduced susceptibility to imipenem. Copyright © 2016 Elsevier Inc. All rights reserved.

Membrane permeability, a pivotal function involved in antibiotic resistance and virulence in Enterobacter aerogenes clinical isolates.

PubMed

Lavigne, J-P; Sotto, A; Nicolas-Chanoine, M-H; Bouziges, N; Bourg, G; Davin-Regli, A; Pagès, J-M

2012-06-01

Imipenem-susceptible E. aerogenes isolates exhibiting extended spectrum β-lactamases, target mutations and a basal efflux expression, were identified in five patients. After imipenem treatment, imipenem-intermediate susceptible (IMI-I) or resistant (IMI-R) isolates emerged in these patients. Alteration in porin synthesis and increase in efflux expression were observed in the IMI-I isolates whereas complete loss of the porins, LPS alteration and efflux overexpression were observed in the IMI-R isolates. Bacterial virulence of the strains was investigated by the Caenorhabditis elegans model. The IMI-R isolates were shown to be significantly less virulent than the IMI-susceptible or IMI-I isolates. The pleiotropic membrane alteration and its associated fitness burden exhibited by E. aerogenes isolates influence their antibiotic resistance and their virulence behaviour. These findings highlight the balance between the low permeability-related resistance and virulence and their relationships with the treatment of resistant pathogens. © 2011 The Authors. Clinical Microbiology and Infection © 2011 European Society of Clinical Microbiology and Infectious Diseases.

Biotransformation of Ferulic acid to 4-Vinylguaiacol by Enterobacter soli and E. aerogenes

USDA-ARS?s Scientific Manuscript database

We investigated the conversion of ferulic acid to 4-vinylguaiacol (4-VG), vanillin, vanillyl alcohol and vanillic acid by five Enterobacter strains. These high-value chemicals are usually synthesized using chemical methods but biological synthesis adds value. Ferulic acid, a relatively inexpensive...

Early Limnology of Dworshak Reservoir. Part 1. Limnology. Part 2. Impact of Log Leachates on Phytoplankton. Part 3. Fate of Phytoplankton and Zooplankton Dynamics. Part 4. Bacteriology.

DTIC Science & Technology

1977-01-01

Streptococcus faecalis var. liquefaciens, Enterobacter aerogenes , and a Salmonella sp. in filtered Dworshak water, 3 August 1973...4-52 * 35, Survival of Escherichia coli, Streptococcus faecalis ./ var. liquefaciens, Enterobacter aerogenes , and a_ _.__ _ _, Salmonella...after appropriate enrich- ment. The organisms and enrichments used were as follows: Escherichia coli, Enterobacter aerogenes and Salmonella; brain heart

Motuporamine Derivatives as Antimicrobial Agents and Antibiotic Enhancers against Resistant Gram-Negative Bacteria.

PubMed

Borselli, Diane; Blanchet, Marine; Bolla, Jean-Michel; Muth, Aaron; Skruber, Kristen; Phanstiel, Otto; Brunel, Jean Michel

2017-02-01

Dihydromotuporamine C and its derivatives were evaluated for their in vitro antimicrobial activities and antibiotic enhancement properties against Gram-negative bacteria and clinical isolates. The mechanism of action of one of these derivatives, MOTU-N44, was investigated against Enterobacter aerogenes by using fluorescent dyes to evaluate outer-membrane depolarization and permeabilization. Its efficiency correlated with inhibition of dye transport, thus suggesting that these molecules inhibit drug transporters by de-energization of the efflux pump rather than by direct interaction of the molecule with the pump. This suggests that depowering the efflux pump provides another strategy to address antibiotic resistance. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Effects of eliminating pyruvate node pathways and of coexpression of heterogeneous carboxylation enzymes on succinate production by Enterobacter aerogenes.

PubMed

Tajima, Yoshinori; Yamamoto, Yoko; Fukui, Keita; Nishio, Yousuke; Hashiguchi, Kenichi; Usuda, Yoshihiro; Sode, Koji

2015-02-01

Lowering the pH in bacterium-based succinate fermentation is considered a feasible approach to reduce total production costs. Newly isolated Enterobacter aerogenes strain AJ110637, a rapid carbon source assimilator under weakly acidic (pH 5.0) conditions, was selected as a platform for succinate production. Our previous work showed that the ΔadhE/PCK strain, developed from AJ110637 with inactivated ethanol dehydrogenase and introduced Actinobacillus succinogenes phosphoenolpyruvate carboxykinase (PCK), generated succinate as a major product of anaerobic mixed-acid fermentation from glucose under weakly acidic conditions (pH <6.2). To further improve the production of succinate by the ΔadhE/PCK strain, metabolically engineered strains were designed based on the elimination of pathways that produced undesirable products and the introduction of two carboxylation pathways from phosphoenolpyruvate and pyruvate to oxaloacetate. The highest production of succinate was observed with strain ES04/PCK+PYC, which had inactivated ethanol, lactate, acetate, and 2,3-butanediol pathways and coexpressed PCK and Corynebacterium glutamicum pyruvate carboxylase (PYC). This strain produced succinate from glucose with over 70% yield (gram per gram) without any measurable formation of ethanol, lactate, or 2,3-butanediol under weakly acidic conditions. The impact of lowering the pH from 7.0 to 5.5 on succinate production in this strain was evaluated under pH-controlled batch culture conditions and showed that the lower pH decreased the succinate titer but increased its yield. These findings can be applied to identify additional engineering targets to increase succinate production. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

A Simple Alternative to the IMViC Test in Microbiology.

ERIC Educational Resources Information Center

Benathen, Isaiah A.

1992-01-01

Presents a singular alternative to the Indole Methyl-red Voges-Proskauer Citrate (IMViC) test that uses bile-esculin agar to distinguish between the Escherichia coli and Enterobacter aerogenes bacteria. Includes materials and methods, results, and conclusions for the test. (MDH)

Molecular characteristics of extended-spectrum beta-lactamases and qnr determinants in Enterobacter species from Japan.

PubMed

Kanamori, Hajime; Yano, Hisakazu; Hirakata, Yoichi; Hirotani, Ayako; Arai, Kazuaki; Endo, Shiro; Ichimura, Sadahiro; Ogawa, Miho; Shimojima, Masahiro; Aoyagi, Tetsuji; Hatta, Masumitsu; Yamada, Mitsuhiro; Gu, Yoshiaki; Tokuda, Koichi; Kunishima, Hiroyuki; Kitagawa, Miho; Kaku, Mitsuo

2012-01-01

The incidence of extended-spectrum β-lactamases (ESBLs) has been increasing worldwide, but screening criteria for detection of ESBLs are not standardized for AmpC-producing Enterobacteriaceae such as Enterobacter species. In this study, we investigated the prevalence of ESBLs and/or AmpC β-lactamases in Japanese clinical isolates of Enterobacter spp. and the association of plasmid-mediated quinolone resistance (PMQR) determinants with ESBL producers. A total of 364 clinical isolates of Enterobacter spp. collected throughout Japan between November 2009 and January 2010 were studied. ESBL-producing strains were assessed by the CLSI confirmatory test and the boronic acid disk test. PCR and sequencing were performed to detect CTX-M, TEM, and SHV type ESBLs and PMQR determinants. For ESBL-producing Enterobacter spp., pulsed-field gel electrophoresis (PFGE) was performed using XbaI restriction enzyme. Of the 364 isolates, 22 (6.0%) were ESBL producers. Seven isolates of Enterobacter cloacae produced CTX-M-3, followed by two isolates producing SHV-12. Two isolates of Enterobacter aerogenes produced CTX-M-2. Of the 22 ESBL producers, 21 had the AmpC enzyme, and six met the criteria for ESBL production in the boronic acid test. We found a significant association of qnrS with CTX-M-3-producing E. cloacae. The 11 ESBL-producing Enterobacter spp. possessing bla(CTX-M), bla(SHV), or bla(TEM) were divided into six unique PFGE types. This is the first report about the prevalence of qnr determinants among ESBL-producing Enterobacter spp. from Japan. Our results suggest that ESBL-producing Enterobacter spp. with qnr determinants are spreading in Japan.

Molecular Characteristics of Extended-Spectrum Beta-Lactamases and qnr Determinants in Enterobacter Species from Japan

PubMed Central

Hirakata, Yoichi; Hirotani, Ayako; Arai, Kazuaki; Endo, Shiro; Ichimura, Sadahiro; Ogawa, Miho; Shimojima, Masahiro; Aoyagi, Tetsuji; Hatta, Masumitsu; Yamada, Mitsuhiro; Gu, Yoshiaki; Tokuda, Koichi; Kunishima, Hiroyuki; Kitagawa, Miho; Kaku, Mitsuo

2012-01-01

The incidence of extended-spectrum β-lactamases (ESBLs) has been increasing worldwide, but screening criteria for detection of ESBLs are not standardized for AmpC-producing Enterobacteriaceae such as Enterobacter species. In this study, we investigated the prevalence of ESBLs and/or AmpC β-lactamases in Japanese clinical isolates of Enterobacter spp. and the association of plasmid-mediated quinolone resistance (PMQR) determinants with ESBL producers. A total of 364 clinical isolates of Enterobacter spp. collected throughout Japan between November 2009 and January 2010 were studied. ESBL-producing strains were assessed by the CLSI confirmatory test and the boronic acid disk test. PCR and sequencing were performed to detect CTX-M, TEM, and SHV type ESBLs and PMQR determinants. For ESBL-producing Enterobacter spp., pulsed-field gel electrophoresis (PFGE) was performed using XbaI restriction enzyme. Of the 364 isolates, 22 (6.0%) were ESBL producers. Seven isolates of Enterobacter cloacae produced CTX-M-3, followed by two isolates producing SHV-12. Two isolates of Enterobacter aerogenes produced CTX-M-2. Of the 22 ESBL producers, 21 had the AmpC enzyme, and six met the criteria for ESBL production in the boronic acid test. We found a significant association of qnrS with CTX-M-3-producing E. cloacae. The 11 ESBL-producing Enterobacter spp. possessing bla CTX-M, bla SHV, or bla TEM were divided into six unique PFGE types. This is the first report about the prevalence of qnr determinants among ESBL-producing Enterobacter spp. from Japan. Our results suggest that ESBL-producing Enterobacter spp. with qnr determinants are spreading in Japan. PMID:22719857

Computational-based structural, functional and phylogenetic analysis of Enterobacter phytases.

PubMed

Pramanik, Krishnendu; Kundu, Shreyasi; Banerjee, Sandipan; Ghosh, Pallab Kumar; Maiti, Tushar Kanti

2018-06-01

Myo-inositol hexakisphosphate phosphohydrolases (i.e., phytases) are known to be a very important enzyme responsible for solubilization of insoluble phosphates. In the present study, Enterobacter phytases have characterized by different phylogenetic, structural and functional parameters using some standard bio-computational tools. Results showed that majority of the Enterobacter phytases are acidic in nature as most of the isoelectric points were under 7.0. The aliphatic indices predicted for the selected proteins were below 40 indicating their thermostable nature. The average molecular weight of the proteins was 48 kDa. The lower values of GRAVY of the said proteins implied that they have better interactions with water. Secondary structure prediction revealed that alpha-helical content was highest among the other forms such as sheets, coils, etc. Moreover, the predicted 3D structure of Enterobacter phytases divulged that the proteins consisted of four monomeric polypeptide chains i.e., it was a tetrameric protein. The predicted tertiary model of E. aerogenes (A0A0M3HCJ2) was deposited in Protein Model Database (Acc. No.: PM0080561) for further utilization after a thorough quality check from QMEAN and SAVES server. Functional analysis supported their classification as histidine acid phosphatases. Besides, multiple sequence alignment revealed that "DG-DP-LG" was the most highly conserved residues within the Enterobacter phytases. Thus, the present study will be useful in selecting suitable phytase-producing microbe exclusively for using in the animal food industry as a food additive.

Impact of heavy metals on hydrogen production from organic fraction of municipal solid waste using co-culture of Enterobacter aerogenes and E. Coli.

PubMed

Sharma, Preeti; Melkania, Uma

2018-05-01

In the present study, the effect of heavy metals (lead, mercury, copper, and chromium) on the hydrogen production from the organic fraction of municipal solid waste (OFMSW) was investigated using co-culture of facultative anaerobes Enterobacter aerogenes and E. coli. Heavy metals were applied at concentration range of 0.5, 1, 2, 5, 10, 20, 50 and 100 mg/L. The results revealed that lead, mercury, and chromium negatively affected hydrogen production for the range of concentrations applied. Application of copper slightly enhanced hydrogen production at low concentration and resulted in the hydrogen yield of 36.0 mLH 2 /gCarbo initial with 10 mg/L copper supplementation as compared to 24.2 mLH 2 /gCarbo initial in control. However, the higher concentration of copper (>10 mg/L) declined hydrogen production. Hydrogen production inhibition potential of heavy metals can be arranged in the following increasing order: Cu 2+  < Cr 6+  < Pb 2+  < Hg 2+ . COD removal rate and volatile fatty acid generation efficiencies were also significantly affected by heavy metal addition. Thus, the present study reveals that the presence of heavy metals in the feedstock is detrimental for the hydrogen production. Therefore, it is essential to remove the toxic heavy metals prior to anaerobic digestion. Copyright © 2018 Elsevier Ltd. All rights reserved.

Evaluation of the methods for enumerating coliform bacteria from water samples using precise reference standards.

PubMed

Wohlsen, T; Bates, J; Vesey, G; Robinson, W A; Katouli, M

2006-04-01

To use BioBall cultures as a precise reference standard to evaluate methods for enumeration of Escherichia coli and other coliform bacteria in water samples. Eight methods were evaluated including membrane filtration, standard plate count (pour and spread plate methods), defined substrate technology methods (Colilert and Colisure), the most probable number method and the Petrifilm disposable plate method. Escherichia coli and Enterobacter aerogenes BioBall cultures containing 30 organisms each were used. All tests were performed using 10 replicates. The mean recovery of both bacteria varied with the different methods employed. The best and most consistent results were obtained with Petrifilm and the pour plate method. Other methods either yielded a low recovery or showed significantly high variability between replicates. The BioBall is a very suitable quality control tool for evaluating the efficiency of methods for bacterial enumeration in water samples.

Stimulating effects of two plant growth-promoting bacteria, Enterobacter ludwigii Ez-185-17 and Raoultella terrigena Ez-555-6, on flax culture

NASA Astrophysics Data System (ADS)

Sarron, Elodie; Clément, Nathalie; Pawlicki-Jullian, Nathalie; Gaillard, Isabelle; Boitel-Conti, Michèle

2018-04-01

Two bacteria, Enterobacter ludwigii Ez-185-17 and Raoultella terrigena Ez-555-6, isolated from root nodules of Medicago lupulina from the Chernobyl exclusion zone, were identified in a previous study and shown not to disturb plant growth. The main goal of this work is to elucidate the relationships between these bacteria and flax, in particular whether they display activities such as plant growth promoting bacteria (PGPB) properties or modulation hairy root development. In order to better understand their role in plants, some known PGPB properties were determined in comparison with several control bacteria. The influence of these bacteria on Linum usitatissimum growth under hydroponic conditions was also investigated. Our study shows that both bacteria belong to PGPB since they were able to increase considerably the root surface area of flax, especially Raoultella terrigena Ez-555-6. Significant IAA production and phosphate solubilization of Enterobacter ludwigii Ez-185-17 were highlighted, which enabled these biochemical PGPB properties to be correlated with their effects on flax growth. However, Raoultella terrigena Ez-555-6 did not express high biochemical activities, suggesting that other PGPB abilities should be studied in order to establish the link with flax growth improvement.

Characterization of In40 of Enterobacter aerogenes BM2688, a Class 1 Integron with Two New Gene Cassettes, cmlA2 and qacF

PubMed Central

Ploy, Marie-Cécile; Courvalin, Patrice; Lambert, Thierry

1998-01-01

Enterobacter aerogenes BM2688, which is resistant to multiple antibiotics, and its aminoglycoside-susceptible derivative BM2688-1 were isolated from the same clinical sample. Strain BM2688 harbored plasmid pIP833, which carries a class 1 integron, In40, containing (in addition to qacEΔ1 and sul1, which are characteristic of class 1 integrons) four gene cassettes: aac(6′)-Ib, qacF, cmlA2, and oxa-9. The cmlA2 gene had 83.7% identity with the previously described nonenzymatic chloramphenicol resistance cmlA1 gene. The qacF gene conferred resistance to quaternary ammonium compounds and displayed a high degree of similarity with qacE (67.8% identity) which, however, has been found as part of a cassette with a very different 59-base element. The oxa-9 gene was not expressed due to a lack of promoter sequences. Study of the antibiotic-susceptible derivative BM2688-1 indicated that a 3,148-bp deletion between the 3′ end of the aac(6′)-Ib gene and the 3′ conserved segment of In40 was responsible for the loss of resistance. The occurrence of this DNA rearrangement, which did not involve homologous sequences, suggests that the In40 integrase could promote recombination at secondary sites. PMID:9756755

Optimization of L-asparaginase production from novel Enterobacter sp., by submerged fermentation using response surface methodology.

PubMed

Erva, Rajeswara Reddy; Goswami, Ajgebi Nath; Suman, Priyanka; Vedanabhatla, Ravali; Rajulapati, Satish Babu

2017-03-16

The culture conditions and nutritional rations influencing the production of extra cellular antileukemic enzyme by novel Enterobacter aerogenes KCTC2190/MTCC111 were optimized in shake-flask culture. Process variables like pH, temperature, incubation time, carbon and nitrogen sources, inducer concentration, and inoculum size were taken into account. In the present study, finest enzyme activity achieved by traditional one variable at a time method was 7.6 IU/mL which was a 2.6-fold increase compared to the initial value. Further, the L-asparaginase production was optimized using response surface methodology, and validated experimental result at optimized process variables gave 18.35 IU/mL of L-asparaginase activity, which is 2.4-times higher than the traditional optimization approach. The study explored the E. aerogenes MTCC111 as a potent and potential bacterial source for high yield of antileukemic drug.

Mechanistic Insight from Calorimetric Measurements of the Assembly of the Binuclear Metal Active Site of Glycerophosphodiesterase (GpdQ) from Enterobacter aerogenes.

PubMed

Pedroso, Marcelo M; Ely, Fernanda; Carpenter, Margaret C; Mitić, Nataša; Gahan, Lawrence R; Ollis, David L; Wilcox, Dean E; Schenk, Gerhard

2017-07-05

Glycerophosphodiesterase (GpdQ) from Enterobacter aerogenes is a binuclear metallohydrolase with a high affinity for metal ions at its α site but a lower affinity at its β site in the absence of a substrate. Isothermal titration calorimetry (ITC) has been used to quantify the Co(II) and Mn(II) binding affinities and thermodynamics of the two sites in wild-type GpdQ and two mutants, both in the absence and in the presence of phosphate. Metal ions bind to the six-coordinate α site in an entropically driven process with loss of a proton, while binding at the β site is not detected by ITC. Phosphate enhances the metal affinity of the α site by increasing the binding entropy and the metal affinity of the β site by enthalpic (Co) or entropic (Mn) contributions, but no additional loss of protons. Mutations of first- and second-coordination sphere residues at the β site increase the metal affinity of both sites by enhancing the binding enthalpy. In particular, loss of the hydrogen bond from second-sphere Ser127 to the metal-coordinating Asn80 has a significant effect on the metal binding thermodynamics that result in a resting binuclear active site with high catalytic activity. While structural and spectroscopic data with excess metal ions have indicated a bridging hydroxide in the binuclear GpdQ site, analysis of ITC data here reveals the loss of a single proton in the assembly of this site, indicating that the metal-bound hydroxide nucleophile is formed in the resting inactive mononuclear form, which becomes catalytically competent upon binding the second metal ion.

Development and Evaluation of Integrity Assessment Tests for Polymeric Hermetic Seals

DTIC Science & Technology

2006-02-19

Knoxville, the wires were pulled from the seals and then the packages were dipped in the microorganism Enterobacter aerogene . The polytrays were exposed for...inoculated) 5 samples Total Polytrays 80 Microorganism Washes 1. Prepare Cultures of Enterobacter aerogenes a. 5 tubes (10 mL each) in...initial number – 6 log CFU/mL a. Add two tubes (20 mL) of Enterobacter aerogenes culture to 5 gallons of water with sodium thiosulfate b. Ca. 9 log CFU

[Post-marketing surveillance of antibacterial activities of cefozopran against various clinical isolates--II. Gram-negative bacteria].

PubMed

Igari, Jun; Oguri, Toyoko; Hiramatsu, Nobuyoshi; Akiyama, Kazumitsu; Koyama, Tsuneo

2002-02-01

As a post-marketing surveillance, the in vitro antibacterial activities of cefozopran (CZOP), an agent of cephems, against various clinical isolates were yearly evaluated and compared with those of other cephems, oxacephems, penicillins, monobactams, and carbapenems. Changes in CZOP susceptibility for the bacteria were also evaluated with the bacterial resistance ratio calculated with the breakpoint MIC. Twenty-five species (3,362 strains) of Gram-negative bacteria were isolated from the clinical materials annually collected from 1996 to 2000, and consisted of Moraxella (Branhamella) catarrhalis (n = 136), Haemophilus influenzae (n = 289), Escherichia coli (n = 276), Klebsiella pneumoniae (n = 192), Klebsiella oxytoca (n = 157), Enterobacter cloacae (n = 189), Enterobacter aerogenes (n = 93), Serratia marcescens (n = 172), Serratia liquefaciens (n = 24), Citrobacter freundii (n = 177), Citrobacter koseri (n = 70), Proteus mirabilis (n = 113), Proteus vulgaris (n = 89), Morganella morganii (n = 116), Providencia spp. (n = 41), Pseudomonas aeruginosa (n = 290), Pseudomonas fluorescens (n = 56), Pseudomonas putida (n = 63), Acinetobacter baumannii (n = 146), Acinetobacter lwoffii (n = 34), Burkholderia cepacia (n = 101), Stenotrophomonas maltophilia (n = 169), Bacteroides fragilis group (n = 196), and Prevotella/Porphyromonas (n = 173). An antibacterial activity of CZOP against E. coli, K. pneumoniae, K. oxytoca, and S. marcescens was potent and consistent with or more preferable than the study results obtained until the new drug application approval. MIC90 of CZOP against M.(B.) catarrhalis, C. koseri, and P. aeruginosa was not considerably changed and consistent with the study results obtained until the new drug application approval. MIC90 of CZOP against E. cloacae, E. aerogenes, and P. mirabilis increased year by year. The increase in MIC90 of CZOP against E. aerogenes and P. mirabilis, however, was not considered to be an obvious decline in susceptibility. In

Emergence of extended-spectrum β-lactamase producing Enterobacter spp. in patients with bacteremia in a tertiary hospital in southern Brazil.

PubMed

Nogueira, Keite da Silva; Paganini, Maria Cristina; Conte, Andréia; Cogo, Laura Lúcia; Taborda de Messias Reason, Iara; da Silva, Márcio José; Dalla-Costa, Libera Maria

2014-02-01

Extended-spectrum β-lactamases (ESBLs) are increasingly prevalent in Enterobacter spp., posing a challenge to the treatment of infections caused by this microorganism. The purpose of this retrospective study was to evaluate the prevalence, risk factors, and clinical outcomes of inpatients with bacteremia caused by ESBL and non ESBL-producing Enterobacter spp. in a tertiary hospital over the period 2004-2008. The presence of blaCTX-M, blaTEM, blaSHV, and blaPER genes was detected by polymerase chain reaction (PCR) and nucleotide sequence analysis. Genetic similarity between strains was defined by pulsed-field gel electrophoresis (PFGE). Enterobacter spp. was identified in 205 of 4907 of the patients who had positive blood cultures during hospitalization. Of those cases, 41 (20%) were ESBL-producing Enterobacter spp. Nosocomial pneumonia was the main source of bacteremia caused by ESBL-producing Enterobacter spp. The presence of this microorganism was associated with longer hospital stays. The ESBL genes detected were: CTX-M-2 (23), CTX-M-59 (10), CTX-M-15 (1), SHV-12 (5), and PER-2 (2). While Enterobacter aerogenes strains showed mainly a clonal profile, Enterobacter cloacae strains were polyclonal. Although no difference in clinical outcomes was observed between patients with infections by ESBL-producing and non-ESBL-producing strains, the detection of ESBL in Enterobacter spp. resulted in the change of antimicrobials in 75% of cases, having important implications in the decision-making regarding adequate antimicrobial therapy. Copyright © 2012 Elsevier España, S.L. All rights reserved.

The spread of bla OXA-48 and bla OXA-244 carbapenemase genes among Klebsiella pneumoniae, Proteus mirabilis and Enterobacter spp. isolated in Moscow, Russia.

PubMed

Fursova, Nadezhda K; Astashkin, Eugeny I; Knyazeva, Anastasia I; Kartsev, Nikolay N; Leonova, Ekaterina S; Ershova, Olga N; Alexandrova, Irina A; Kurdyumova, Natalia V; Sazikina, Svetlana Yu; Volozhantsev, Nikolay V; Svetoch, Edward A; Dyatlov, Ivan A

2015-11-02

The spread of carbapenemase-producing Enterobacteriaceae (CPE) is a great problem of healthcare worldwide. Study of the spread for bla OXA-48-like genes coding epidemically significant carbapenemases among hospital pathogens is important for the regional and global epidemiology of antimicrobial resistance. Antibacterial resistant isolates of Klebsiella pneumoniae (n = 95) from 54 patients, P. mirabilis (n = 32) from 20 patients, Enterobacter aerogenes (n = 6) from four patients, and Enterobacter cloacae (n = 4) from four patients were collected from January, 2013 to October, 2014 in neurosurgical intensive care unit (ICU) of the Burdenko Neurosurgery Institute, Moscow. Characteristics of the isolates were done using susceptibility tests, PCR detection of the resistance genes, genotyping, conjugation, DNA sequencing, and bioinformatic analysis. Major strains under study were multi drug resistant (MDR), resistant to three or more functional classes of drugs simultaneously-98.9 % K. pneumoniae, 100 % P. mirabilis, one E. aerogenes isolate, and one E. cloacae isolate. Molecular-genetic mechanism of MDR in K. pneumoniae and P. mirabilis isolates were based on carrying of epidemic extended-spectrum beta-lactamase bla CTX-M-15 gene (87.2 and 90.6 % accordingly), carbapenemase bla OXA-48-like gene (55.3 and 23.3 % accordingly), and class 1 (54.8 and 31.3 % accordingly) and class 2 (90.6 % P. mirabilis) integrons. The bla OXA-48-like-positive K. pneumoniae were collected during whole two-year surveillance period, while P. mirabilis and Enterobacter spp. carrying bla OXA-48-like genes were detected only after four and 18 months after the research start, respectively. The bla OXA-48-like gene acquisition was shown for P. mirabilis isolates collected from five patients and for E. cloacae isolate collected from one patient during their stay in the ICU, presumably from bla OXA-48-like-positive K. pneumoniae. The source of the bla OXA-244 gene acquired by E. aerogenes

Detection of Staphylococcus Aureus Enterotoxin A and B Genes with PCR-EIA and a Hand-Held Electrochemical Sensor

DTIC Science & Technology

2004-06-11

Streptococcus pneumoniae 33400 Enterobacter cloaceae 49141 S. pyogenes 19615 E. aerogenes m10822 Vibrio cholerae N16961 Enterococcus durans 6056 Yersinia...identified. Thus the sensitivity for both assays was 100%. Of the 56 samples that lacked sea or seb genes, two false positives ( Enterobacter aerogenes ...Comanonas, Enterobacter , Enterococcus, Escherichia, Francisella, Haemophilus, Klebsiella, Listeria, Moraxella, Neisseria, Proteus, Pseudomonas, Salmonella

In Vitro antibacterial efficacy of 21 Indian timber-yielding plants against multidrug-resistant bacteria causing urinary tract infection.

PubMed

Mishra, Monali P; Padhy, Rabindra N

2013-12-01

To screen methanolic leaf extracts of 21 timber-yielding plants for antibacterial activity against nine species of uropathogenic bacteria isolated from clinical samples of a hospital (Enterococcus faecalis, Staphylococcus aureus, Acinetobacter baumannii, Citrobacter freundii, Enterobacter aerogenes, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, and Pseudomonas aeruginosa). Bacterial strains were subjected to antibiotic sensitivity tests by the Kirby-Bauer's disc diffusion method. The antibacterial potentiality of leaf extracts was monitored by the agar-well diffusion method with multidrug-resistant (MDR) strains of nine uropathogens. Two Gram-positive isolates, E. faecalis and S. aureus, were resistant to 14 of the 18 antibiotics used. Gram-negative isolates A. baumannii, C. freundii, E. aerogenes, E. coli, K. pneumoniae, P. mirabilis, and P. aeruginosa were resistant to 10, 12, 9, 11, 11, 10, and 11 antibiotics, respectively, of the 14 antibiotics used. Methanolic leaf extracts of Anogeissus acuminata had the maximum zone of inhibition size-29 mm against S. aureus and 28 mm against E. faecalis and P. aeruginosa. Cassia tora had 29 mm as the zone of inhibition size for E. faecalis, E. aerogenes, and P. aeruginosa. Based on the minimum inhibitory concentration and minimum bactericidal concentration values, the most effective 10 plants against uropathogens could be arranged in decreasing order as follows: C. tora > A. acuminata > Schleichera oleosa > Pterocarpus santalinus > Eugenia jambolana > Bridelia retusa > Mimusops elengi > Stereospermum kunthianum > Tectona grandis > Anthocephalus cadamba. The following eight plants had moderate control capacity: Artocarpus heterophyllus, Azadirachta indica, Dalbergia latifolia, Eucalyptus citriodora, Gmelina arborea, Pongamia pinnata, Pterocarpus marsupium, and Shorea robusta. E. coli, followed by A. baumannii, C. freundii, E. aerogenes, P. mirabilis, and P. aeruginosa were controlled by

In Vitro Antibacterial Efficacy of 21 Indian Timber-Yielding Plants Against Multidrug-Resistant Bacteria Causing Urinary Tract Infection

PubMed Central

Mishra, Monali P.; Padhy, Rabindra N.

2013-01-01

Objectives To screen methanolic leaf extracts of 21 timber-yielding plants for antibacterial activity against nine species of uropathogenic bacteria isolated from clinical samples of a hospital (Enterococcus faecalis, Staphylococcus aureus, Acinetobacter baumannii, Citrobacter freundii, Enterobacter aerogenes, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, and Pseudomonas aeruginosa). Methods Bacterial strains were subjected to antibiotic sensitivity tests by the Kirby–Bauer's disc diffusion method. The antibacterial potentiality of leaf extracts was monitored by the agar-well diffusion method with multidrug-resistant (MDR) strains of nine uropathogens. Results Two Gram-positive isolates, E. faecalis and S. aureus, were resistant to 14 of the 18 antibiotics used. Gram-negative isolates A. baumannii, C. freundii, E. aerogenes, E. coli, K. pneumoniae, P. mirabilis, and P. aeruginosa were resistant to 10, 12, 9, 11, 11, 10, and 11 antibiotics, respectively, of the 14 antibiotics used. Methanolic leaf extracts of Anogeissus acuminata had the maximum zone of inhibition size—29 mm against S. aureus and 28 mm against E. faecalis and P. aeruginosa. Cassia tora had 29 mm as the zone of inhibition size for E. faecalis, E. aerogenes, and P. aeruginosa. Based on the minimum inhibitory concentration and minimum bactericidal concentration values, the most effective 10 plants against uropathogens could be arranged in decreasing order as follows: C. tora > A. acuminata > Schleichera oleosa > Pterocarpus santalinus > Eugenia jambolana > Bridelia retusa > Mimusops elengi > Stereospermum kunthianum > Tectona grandis > Anthocephalus cadamba. The following eight plants had moderate control capacity: Artocarpus heterophyllus, Azadirachta indica, Dalbergia latifolia, Eucalyptus citriodora, Gmelina arborea, Pongamia pinnata, Pterocarpus marsupium, and Shorea robusta. E. coli, followed by A. baumannii, C. freundii, E. aerogenes, P. mirabilis, and P

Infection rate in adult patients with open fractures treated at the emergency hospital and at the ULBRA university hospital in Canoas, Rio Grande do Sul, Brazil.

PubMed

Guerra, Marcelo Teodoro Ezequiel; Gregio, Fernando Machado; Bernardi, Adriane; Castro, Cyntia Cordeiro de

2017-01-01

To identify the infection rate in adult patients with open fractures treated at two tertiary hospitals in the city of Canoas, Rio Grande do Sul, Brazil. This quantitative descriptive study was conducted at Hospital de Pronto Socorro de Canoas. Eligible participants were adults aged 18-60 years with open fractures who were admitted to the orthopedic trauma service from January to May 2014 and followed-up for one year. A total of 133 patients with open fractures were included; most were men (92.48%), with a mean age of 36 years. There was a predominance of Gustilo-Anderson type III fractures. The infection rate was 18.80%, being more frequent in Gustilo-Anderson type III fractures (72.00%). The most commonly observed bacteria were Staphylococcus aureus and Enterobacter aerogenes . The infection rate in open fractures of patients initially treated at the emergency department of HPSC was 18.8%. The infections occurred predominantly in Gustilo-Anderson type III fractures. The bacteria with the highest incidence in infections were Staphylococcus aureus and Enterobacter aerogenes .

Comprehensive Genome Analysis of Carbapenemase-Producing Enterobacter spp.: New Insights into Phylogeny, Population Structure, and Resistance Mechanisms

PubMed Central

Chavda, Kalyan D.; Chen, Liang; Fouts, Derrick E.; Sutton, Granger; Brinkac, Lauren; Jenkins, Stephen G.; Bonomo, Robert A.

2016-01-01

ABSTRACT Knowledge regarding the genomic structure of Enterobacter spp., the second most prevalent carbapenemase-producing Enterobacteriaceae, remains limited. Here we sequenced 97 clinical Enterobacter species isolates that were both carbapenem susceptible and resistant from various geographic regions to decipher the molecular origins of carbapenem resistance and to understand the changing phylogeny of these emerging and drug-resistant pathogens. Of the carbapenem-resistant isolates, 30 possessed blaKPC-2, 40 had blaKPC-3, 2 had blaKPC-4, and 2 had blaNDM-1. Twenty-three isolates were carbapenem susceptible. Six genomes were sequenced to completion, and their sizes ranged from 4.6 to 5.1 Mbp. Phylogenomic analysis placed 96 of these genomes, 351 additional Enterobacter genomes downloaded from NCBI GenBank, and six newly sequenced type strains into 19 phylogenomic groups—18 groups (A to R) in the Enterobacter cloacae complex and Enterobacter aerogenes. Diverse mechanisms underlying the molecular evolutionary trajectory of these drug-resistant Enterobacter spp. were revealed, including the acquisition of an antibiotic resistance plasmid, followed by clonal spread, horizontal transfer of blaKPC-harboring plasmids between different phylogenomic groups, and repeated transposition of the blaKPC gene among different plasmid backbones. Group A, which comprises multilocus sequence type 171 (ST171), was the most commonly identified (23% of isolates). Genomic analysis showed that ST171 isolates evolved from a common ancestor and formed two different major clusters; each acquiring unique blaKPC-harboring plasmids, followed by clonal expansion. The data presented here represent the first comprehensive study of phylogenomic interrogation and the relationship between antibiotic resistance and plasmid discrimination among carbapenem-resistant Enterobacter spp., demonstrating the genetic diversity and complexity of the molecular mechanisms driving antibiotic resistance in this

Heat Resistance of Histidine Decarboxylase from Gram-Negative Histamine-Producing Bacteria in Seafood.

PubMed

Bjornsdottir-Butler, K; Bencsath, F A; McCarthy, S; Benner, R A

2017-08-01

Precooking of tuna is a potential critical control point (CCP) in the commercial manufacturing of canned tuna. To assess the efficacy of precooking as a CCP, an understanding of the thermal properties of histamine-producing bacteria (HPB) and their histidine decarboxylase (HDC) enzymes is required. The thermal properties of many HPB have been determined, but the thermal resistances of the HDC enzymes are unknown. The purpose of this study was to determine the D- and z-values of selected HDC enzymes to evaluate the CCP of precooking during the canning process and provide scientific data to support U.S. Food and Drug Administration guidelines. HDC (hdc) genes from three strains each of Morganella morganii, Enterobacter aerogenes, Raoultella planticola, and Photobacterium damselae were cloned, expressed, and purified using the Champion pET Directional TOPO Expression System, pET100 cloning vector, and HisPur Cobalt resin. The heat resistances of all enzymes were compared at 50°C, and the D- and z-values from one strain of each HPB were determined at 50 to 60°C. To evaluate the heat inactivation of HDC enzymes during canned tuna processing, tuna tissue was inoculated with HDCs and heated to 60°C in a water bath set at 65 and 100°C. The D-values for the HDC enzymes from M. morganii, E. aerogenes, R. planticola, and P. damselae ranged from 1.6 to 4.1, 1.6 to 6.3, 1.9 to 4.3, and 1.6 to 2.9 min, respectively, at 50 to 60°C. The z-values for M. morganii, E. aerogenes, R. planticola, and P. damselae were 19.2, 18.0, 22.0, and 13.3°C, respectively. The HDCs from all HPB except E. aerogenes showed no significant activity after being heated to 60°C. The data generated in this study will help refine current guidelines for the thermal destruction of the HDC enzymes.

Surveillance of multidrug resistant uropathogenic bacteria in hospitalized patients in Indian

PubMed Central

Mishra, Monali Priyadarsini; Debata, Nagen Kumar; Padhy, Rabindra Nath

2013-01-01

Objective To record surveillance, antibiotic resistance of uropathogens of hospitalized patients over a period of 18 months. Methods Urine samples from wards and cabins were used for isolating urinary tract infection (UTI)-causing bacteria that were cultured on suitable selective media and identified by biochemical tests; and their antibiograms were ascertained by Kirby-Bauer's disc diffusion method, in each 6-month interval of the study period, using 18 antibiotics of five different classes. Results From wards and cabins, 1 245 samples were collected, from which 996 strains of bacteria belonging to 11 species were isolated, during April 2011 to September 2012. Two Gram-positive, Staphylococcus aureus (S. aureus) and Enterococcus faecalis (E. faecalis), and nine Gram-negative bacteria, Acinetobacter baumannii, Citrobacter sp., Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, Klebsiella oxytoca, Proteus mirabilis, Proteus vulgaris and Pseudomonas aeruginosa were isolated. Both S. aureus and E. faecalis were vancomycin resistant, and resistant-strains of all pathogens increased in each 6-month period of study. Particularly, all Gram-negatives were resistant to nitrofurantoin and co-trimoxazole, the most preferred antibiotics of empiric therapy for UTI. Conclusions Antibiograms of 11 UTI-causing bacteria recorded in this study indicated moderately higher numbers of strains resistant to each antibiotic studied, generating the fear of precipitating fervent episodes in public health particularly with bacteria, Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae and S. aureus. Moreover, vancomycin resistance in strains of S. aureus and E. faecalis is a matter of concern. PMID:23620859

Comprehensive Genome Analysis of Carbapenemase-Producing Enterobacter spp.: New Insights into Phylogeny, Population Structure, and Resistance Mechanisms.

PubMed

Chavda, Kalyan D; Chen, Liang; Fouts, Derrick E; Sutton, Granger; Brinkac, Lauren; Jenkins, Stephen G; Bonomo, Robert A; Adams, Mark D; Kreiswirth, Barry N

2016-12-13

Knowledge regarding the genomic structure of Enterobacter spp., the second most prevalent carbapenemase-producing Enterobacteriaceae, remains limited. Here we sequenced 97 clinical Enterobacter species isolates that were both carbapenem susceptible and resistant from various geographic regions to decipher the molecular origins of carbapenem resistance and to understand the changing phylogeny of these emerging and drug-resistant pathogens. Of the carbapenem-resistant isolates, 30 possessed bla KPC-2 , 40 had bla KPC-3 , 2 had bla KPC-4 , and 2 had bla NDM-1 Twenty-three isolates were carbapenem susceptible. Six genomes were sequenced to completion, and their sizes ranged from 4.6 to 5.1 Mbp. Phylogenomic analysis placed 96 of these genomes, 351 additional Enterobacter genomes downloaded from NCBI GenBank, and six newly sequenced type strains into 19 phylogenomic groups-18 groups (A to R) in the Enterobacter cloacae complex and Enterobacter aerogenes Diverse mechanisms underlying the molecular evolutionary trajectory of these drug-resistant Enterobacter spp. were revealed, including the acquisition of an antibiotic resistance plasmid, followed by clonal spread, horizontal transfer of bla KPC -harboring plasmids between different phylogenomic groups, and repeated transposition of the bla KPC gene among different plasmid backbones. Group A, which comprises multilocus sequence type 171 (ST171), was the most commonly identified (23% of isolates). Genomic analysis showed that ST171 isolates evolved from a common ancestor and formed two different major clusters; each acquiring unique bla KPC -harboring plasmids, followed by clonal expansion. The data presented here represent the first comprehensive study of phylogenomic interrogation and the relationship between antibiotic resistance and plasmid discrimination among carbapenem-resistant Enterobacter spp., demonstrating the genetic diversity and complexity of the molecular mechanisms driving antibiotic resistance in this

SEM study of the effects of bacteria and yeasts on wood decay by brown and white-rot fungi. [Enterobacter, Cryptococcus Pichia, and Saccharomyces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blanchette, R.A.; Shaw, C.G.; Cohen, A.L.

The scanning electron microscope was used to 1) examine the associations among microorganisms during wood decay and 2) observe the effect of these organisms on degradation of cell wall components. Bacteria (Enterobacter) and yeasts (Cryptococcus Pichia, and Saccharomyces) were found to have a mutualistic association with a white-rot fungus during decay of coniferous wood. Coriolus (Polyporus versicolar) degraded cell wall components in a typical ''erosion trough'' manner (i.e., by lysing zones around fungal hyphae). Bacteria and yeasts were seen only in these lysed zones. Typical gross decay patterns caused by the white-rot fungus were unaltered by bacteria and yeasts. Themore » SEM study suggests that the decay process is enhanced when these organisms are associated. In contrast, the same bacteria and yeasts were inhibitory when combined with a brown-rot fungus.« less

Plant growth promoting potential and phylogenetic characteristics of a lichenized nitrogen fixing bacterium, Enterobacter cloacae.

PubMed

Swamy, Chidanandamurthy Thippeswamy; Gayathri, Devaraja; Devaraja, Thimmalapura Neelakantaiah; Bandekar, Mandar; D'Souza, Stecy Elvira; Meena, Ram Murti; Ramaiah, Nagappa

2016-12-01

Lichens are complex symbiotic association of mycobionts, photobionts, and bacteriobionts, including chemolithotropic bacteria. In the present study, 46 lichenized bacteria were isolated by conventional and enrichment culture methods on nitrogen-free bromothymol blue (NFb) medium. Only 11 of the 46 isolates fixed nitrogen on NFb and had reduced acetylene. All these 11 isolates had also produced siderophore and 10 of them the IAA. Further, ammonia production was recorded from nine of these nitrogen fixers (NF). On molecular characterization, 16 S rRNA sequencing recorded that, nine NF belonged to Proteobacteria, within Gammaproteobacteria, and were closely related to Enterobacter sp. with a maximum similarity to Enterobacter cloacae. Each one of our NF isolates was aligned closely to Enterobacter pulveris strain E443, Cronobacter sakazakii strain PNP8 and Providencia rettgeri strain ALK058. Notably, a few strains we examined found to possess plant growth promoting properties. This is the first report of Enterobacter sp. from lichens which may be inhabit lichen thalli extrinsically or intrinsically. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Incidence of multiple antibiotic resistant Gram-negative bacteria isolated from surface and underground water sources in south western region of Nigeria.

PubMed

Oluyege, J O; Dada, A C; Odeyemi, A T

2009-01-01

In most rural and urban settlements, particularly in Nigeria, wells, spring, streams or rivers and lakes serves as major sources of water supply for drinking and other domestic purposes. Unfortunately, many of the available water sources are not potable without some form of treatment which is seldom available in most settings. The use of untreated surface water sources for drinking and for domestic purposes remains a major threat to public health as these could serve as reservoirs the for transfer of antibiotic resistant pathogens. The incidence of resistant bacteria isolated from surface and underground water in six rural settlements in Ekiti State Nigeria was thus investigated. Gram-negative bacteria were isolated from wells, streams and boreholes in six rural settlements in Ekiti State Nigeria between January and April, 2006 and the prevalence of organisms exhibiting multiple antibiotic resistance to tetracycline, amoxicillin, cotrimoxazole, nitofurantoin, gentamicin, nalidixic acid and ofloxacin was observed. Gram-negative bacterial isolates comprised Escherichia coli (22.7%), Enterobacter aerogenes (2.5%), Salmonella spp. (13.3%), Shigella spp. (19.3%), Proteus spp. (18.5%), Klebsiella spp. (19.3%) and Pseudomonas aeruginosa (4.2%). Over 10% of the bacteria were resistant to four or more antibiotic. Antibiotic resistance was highest in members of the genera Enterobacter, Pseudomonas, and Proteus. Given the prevalence of appalling sanitary facilities and inappropriate public antibiotic use, the possibility of antibiotic resistance selection, faecal dissemination and subsequent contamination of local water sources available for rural residents of the developing world is highlighted. The implication for clinical practice of infections caused by antibiotic resistant strains especially among immunodeficient individuals is also discussed.

Mathematical modeling and assessment of microbial migration during the sprouting of alfalfa in trays in a nonuniformly contaminated seed batch using Enterobacter aerogenes as a surrogate for Salmonella Stanley.

PubMed

Liu, Bin; Schaffner, Donald W

2007-11-01

Raw seed sprouts have been implicated in several food poisoning outbreaks in the past 10 years. The U.S. Food and Drug Administration recommends that sprout growers use interventions (such as testing of spent irrigation water) to control the presence of pathogens in the finished product. During the sprouting process, initially low concentrations of pathogen may increase, and contamination may spread within a batch of sprouting seeds. A model of pathogen growth as a function of time and distance from the contamination spot during the sprouting of alfalfa in trays has been developed with Enterobacter aerogenes. The probability of detecting contamination was assessed by logistic regression at various time points and distances by sampling from sprouts or irrigation water. Our results demonstrate that microbial populations and possibility of detection were greatly reduced at distances of > or = 20 cm from the point of contamination in a seed batch during tray sprouting; however, the probability of detecting microbial contamination at distances less than 10 cm from the point of inoculation was almost 100% at the end of the sprouting process. Our results also show that sampling irrigation water, especially large volumes of water, is highly effective at detecting contamination: by collecting 100 ml of irrigation water for membrane filtration, the probability of detection was increased by three to four times during the first 6 h of seed germination. Our findings have quantified the degree to which a small level of contamination will spread throughout a tray of sprouting alfalfa seeds and subsequently be detected by either sprout or irrigation water sampling.

An Enterobacter Plasmid as a New Genetic Background for the Transposon Tn1331

DTIC Science & Technology

2011-11-25

determined to be 99% similar to E. cloacae by both 16S rDNA and Phoenix analysis and was designated Enterobacter sp W001. Enterobacter sp W001 was...adolescents. JAMA. 2002;287(23):3096–3102. 9. Foster TJ. Plasmid- determined resistance to antimicrobial drugs and toxic metal ions in bacteria. Microbiol...mediated type II dihydrofolate reductase gene among trimethoprim -resistant urinary pathogens in Greek hospitals. J Antimicrob Chemother. 1992;29

Sanitary and bacteriological aspects of sewage treatment.

PubMed

Filipkowska, Zofia

2003-01-01

A study into the removal of contamination load and indicator bacteria was carried out in 1992-1996 in the mechanical, biological and chemical waste-water treatment plant WTP in Lezany, in the County of Reszel, in the Province of Warmia and Mazury in Poland. The results of chemical analyses found a high efficiency of removal of carbon compounds, COD (90%) and BOD (98%), in the process of purification of household sewage. In addition, a high effectiveness of total nitrogen, on average 71%, and unsatisfactory removal of ammonia nitrogen and phosphorus compounds were found. The results of microbiological analyses confirmed the high efficiency of removal of indicator bacteria in the process of sewage treatment from 94 to 97%. In the sewage after the final phase of purification in stabilization ponds, the following pathogenic bacteria were identified with the use of the EPL 21tests: Escherichia coli, Enterobacter agglomerans, Enterobacter aerogenes, Enterobacter cloacae, Enterobacter georgoriae, Citrobacter freundii, Klebsiella pnemoniae, Klebsiella oxytoca, Klebsiella ozaenae, Ervinia herbicola, Edwardsiella tarda, Serratia odoriefra, Serratia marcescens, Providencia alcalifaciens, Hafnia alvei, Yersina pestis, Yersina pseudotuberculosis, Yersinia fredericksenii, Salmonella spp., Shigella dysenteriae, Aeromons hydrophila, Pseudomonas aerulginosa. The obtained results show that although the sewage purification system is efficient and reduces the contamination load to the level required by the regulations (Ministry of Environmental Protection, Natural Resources and Forestry from 20 September 1991) and removes a great percentage of indicator bacteria, the purified sewage may be a source of pathogenic bacteria in inland waters.

Formation of methyl mercury by bacteria

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hamdy, M.K.; Noyes, O.R.

1975-09-01

Twenty-three Hg/sup 2 +/-resistant cultures were isolated from sediment of the Savannah River in Georgia; of these, 14 were gram-negative short rods belonging to the genera Escherichia and Enterobacter, six were gram-positive cocci (three Staphylococcus sp. and three Streptococcus sp.) and three were Bacillus sp. All the Escherichia, Enterobacter, and the Bacillus strain were more resistant to Hg/sup 2 +/ than the strains of staphylococci and streptococci. Adaptation using serial dilutions and concentration gradient agar plant techniques showed that it was possible to select a Hg/sup 2 +/-resistant strain from a parent culture identified as Enterobacter aerogenes. This culture resistedmore » 1200 ..mu..g of Hg/sup 2 +/ per ml of medium and produced methyl mercury from HgCl/sub 2/, but was unable to convert Hg/sup 2 +/ to volatile elemental mercury (Hg/sup 0/). Under constant aeration (i.e., submerged culture), slightly more methyl mercury was formed than in the absence of aeration. Production of methyl mercury was cyclic in nature and slightly decreased if DL-homocysteine was present in media, but increased with methylcobalamine. It is concluded that the bacterial production of methyl mercury may be a means of resistance and detoxification against mercurials in which inorganic Hg/sup 2 +/ is converted to organic form and secreted into the environment. 39 references, 5 figures, 3 tables.« less

Formation of methyl mercury by bacteria

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hamdy, M.K.; Noyes, O.R.

1975-09-01

Twenty-three Hg/sup 2 +/-resistant cultures were isolated from sediment of the Savannah River in Georgia; of these, 14 were gram-negative short rods belonging to the genera Escherichia and Enterobacter, six were gram-positive cocci (three Staphylococcus sp. and three Streptococcus sp.) and three were Bacillus sp. All the Escherichia, Enterobacter, and the Bacillus strain were more resistant to Hg/sup 2 +/ than the strains of staphylococci and streptococci. Adaptation using serial dilutions and concentration gradient agar plate techniques showed that it was possible to select a Hg/sup 2 +/-resistant strain from a parent culture identified as Enterobacter aerogenes. This culture resistedmore » 1,200 ..mu..g of Hg/sup 2 +/ per ml of medium and produced methyl mercury from HgCl/sub 2/, but was unable to convert Hg/sup 2 +/ to volatile elemental mercury (Hg/sup 0/). Under constant aeration (i.e., submerged culture), slightly more methyl mercury was formed than in the absence of aeration. Production of methyl mercury was cycle in nature and slightly decreased if DL-homocysteine was present in media, but increased with methylcobalamine. It is concluded that the bacterial production of methyl mercury may be a means of resistance and detoxification against mercurials in which inorganic Hg/sup 2 +/ is converted to organic form and secreted into the environment.« less

Inoculation of hybrid poplar with the endophytic bacterium Enterobacter sp. 638 increases biomass but does not impact leaf level physiology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rogers, A.; McDonald, K.; Muehlbauer, M. F.

Endophytic bacteria have been shown to provide several advantages to their host, including enhanced growth. Inoculating biofuel species with endophytic bacteria is therefore an attractive option to increase the productivity of biofuel feedstocks. Here, we investigated the effect of inoculating hard wood cuttings of Populus deltoides Bartr. x Populus. nigra L. clone OP367 with Enterobacter sp. 638. After 17 weeks, plants inoculated with Enterobacter sp. 638 had 55% greater total biomass than un-inoculated control plants. Study of gas exchange and fluorescence in developing and mature leaves over a diurnal cycle and over a 5 week measurement campaign revealed no effectsmore » of inoculation on photosynthesis, stomatal conductance, photosynthetic water use efficiency or the maximum and operating efficiency of photosystem II. However, plants inoculated with Enterobacter sp. 638 had a canopy that was 39% larger than control plants indicating that the enhanced growth was fueled by increased leaf area, not by improved physiology. Leaf nitrogen content was determined at two stages over the 5 week measurement period. No effect of Enterobacter sp. 638 on leaf nitrogen content was found indicating that the larger plants were acquiring sufficient nitrogen. Enterobacter sp. 638 lacks the genes for N{sub 2} fixation, therefore the increased availability of nitrogen likely resulted from enhanced nitrogen acquisition by the 84% larger root system. These data show that Enterobacter sp. 638 has the potential to dramatically increase productivity in poplar. If fully realized in the production environment, these results indicate that an increase in the environmental and economic viability of poplar as a biofuel feedstock is possible when inoculated with endophytic bacteria like Enterobacter sp. 638.« less

Rapid identification of Enterobacter hormaechei and Enterobacter cloacae genetic cluster III.

PubMed

Ohad, S; Block, C; Kravitz, V; Farber, A; Pilo, S; Breuer, R; Rorman, E

2014-05-01

Enterobacter cloacae complex bacteria are of both clinical and environmental importance. Phenotypic methods are unable to distinguish between some of the species in this complex, which often renders their identification incomplete. The goal of this study was to develop molecular assays to identify Enterobacter hormaechei and Ent. cloacae genetic cluster III which are relatively frequently encountered in clinical material. The molecular assays developed in this study are qPCR technology based and served to identify both Ent. hormaechei and Ent. cloacae genetic cluster III. qPCR results were compared to hsp60 sequence analysis. Most clinical isolates were assigned to Ent. hormaechei subsp. steigerwaltii and Ent. cloacae genetic cluster III. The latter was proportionately more frequently isolated from bloodstream infections than from other material (P < 0·05). The qPCR assays detecting Ent. hormaechei and Ent. cloacae genetic cluster III demonstrated high sensitivity and specificity. The presented qPCR assays allow accurate and rapid identification of clinical isolates of the Ent. cloacae complex. The improved identifications obtained can specifically assist analysis of Ent. hormaechei and Ent. cloacae genetic cluster III in nosocomial outbreaks and can promote rapid environmental monitoring. An association was observed between Ent. cloacae cluster III and systemic infection that deserves further attention. © 2014 The Society for Applied Microbiology.

Volatiles produced by soil-borne endophytic bacteria increase plant pathogen resistance and affect tritrophic interactions

PubMed Central

Ton, Jurriaan; Brandenburg, Anna; Karlen, Danielle; Zopfi, Jakob; Turlings, Ted C. J.

2014-01-01

Volatile organic compounds (VOCs) released by soil microorganisms influence plant growth and pathogen resistance. Yet, very little is known about their influence on herbivores and higher trophic levels. We studied the origin and role of a major bacterial VOC, 2,3-butanediol (2,3-BD), on plant growth, pathogen and herbivore resistance, and the attraction of natural enemies in maize. One of the major contributors to 2,3-BD in the headspace of soil-grown maize seedlings was identified as Enterobacter aerogenes, an endophytic bacterium that colonizes the plants. The production of 2,3-BD by E. aerogenes rendered maize plants more resistant against the Northern corn leaf blight fungus Setosphaeria turcica. On the contrary, E. aerogenes-inoculated plants were less resistant against the caterpillar Spodoptera littoralis. The effect of 2,3-BD on the attraction of the parasitoid Cotesia marginiventris was more variable: 2,3-BD application to the headspace of the plants had no effect on the parasitoids, but application to the soil increased parasitoid attraction. Furthermore, inoculation of seeds with E. aerogenes decreased plant attractiveness, whereas inoculation of soil with a total extract of soil microbes increased parasitoid attraction, suggesting that the effect of 2,3-BD on the parasitoid is indirect and depends on the composition of the microbial community. PMID:24127750

Biogenic amine content, histamine-forming bacteria, and adulteration of pork in tuna sausage products.

PubMed

Kung, Hsien-Feng; Tsai, Yung-Hsiang; Chang, Shih-Chih; Hong, Tang-Yao

2012-10-01

Twenty-five tuna sausage products were purchased from retail markets in Taiwan. The rates of occurrence of biogenic amines, histamine-forming bacteria, and adulteration by pork and poultry were determined. The average content of various biogenic amines in all tested samples was less than 2.0 mg/100 g (<0.05 to 1.85 mg/100 g). Thirteen histamine-producing bacterial strains isolated from tested samples produced 12.1 to 1,261 ppm of histamine in Trypticase soy broth supplemented with 1.0% L-histidine. Among them, Raoultella ornithinolytica (one strain), Enterobacter aerogenes (one strain), and Staphylococcus pasteuri (two strains) were identified as prolific histamine formers. PCR assay revealed that the adulteration rates were 80% (20 of 25) and 4% (1 of 25) for pork and poultry, respectively, in tuna sausage. The fish species in the tuna sausage samples were identified as Thunnus albacares for 22 samples (88%), Thunnus alalunga for 1 sample (4%), and Thunnus thynnus for 1 sample (4%), whereas the remaining sample was identified as Makaira nigricans (blue marlin).

Characterization of the Origin of DNA Replication of the Coxiella burnetii Chromosome

DTIC Science & Technology

1990-01-26

chromosomal DNAs (FIG. IB): the 19.4-kb EcoR I fragment of Salmonella typhimurium DNA (lane 4),9 the 17.5-kb Sal I fragment of Enterobacter aerogenes ...IacZYA-argF) U 1694680d IacZAM15 Salmonella typhimurium Wild type WVUd Kiebsiella pneumoniae Wild type WVUd Enterobacter aero genes Wild type WVUd... aerogenes and K. pneumoniae were digested with appropriate restriction enzymes. The restriction fragments were separated on a 0.9% agarose gel, transferred to

Evaluation of the MicroScan ESBL plus confirmation panel for detection of extended-spectrum beta-lactamases in clinical isolates of oxyimino-cephalosporin-resistant Gram-negative bacteria.

PubMed

Stürenburg, Enno; Lang, Melanie; Horstkotte, Matthias A; Laufs, Rainer; Mack, Dietrich

2004-11-01

We aimed to assess the performance of the MicroScan ESBL plus confirmation panel using a series of 87 oxyimino-cephalosporin-resistant Gram-negative bacilli of various species. Organisms tested included 57 extended-spectrum beta-lactamase (ESBL) strains comprising Enterobacter aerogenes (3), Enterobacter cloacae (10), Escherichia coli (11), Klebsiella pneumoniae (26), Klebsiella oxytoca (3) and Proteus mirabilis (4). Also included were 30 strains resistant to oxyimino cephalosporins but lacking ESBLs, which were characterized with other resistance mechanisms, such as inherent clavulanate susceptibility in Acinetobacter spp. (4), hyperproduction of AmpC enzyme in Citrobacter freundii (2), E. aerogenes (3), E. cloacae (3), E. coli (4), Hafnia alvei (1) and Morganella morganii (1), production of plasmid-mediated AmpC beta-lactamase in K. pneumoniae (3) and E. coli (3) or hyperproduction of K1 enzyme in K. oxytoca (6). The MicroScan MIC-based clavulanate synergy correctly classified 50 of 57 ESBL strains as ESBL-positive and 23 of 30 non-ESBL strains as ESBL-negative (yielding a sensitivity of 88% and a specificity of 76.7%, respectively). False negatives among ESBL producers were highest with Enterobacter spp. due to masking interactions between ESBL and AmpC beta-lactamases. False-positive classifications occurred in two Acinetobacter spp., one E. coli producing plasmid-mediated AmpC beta-lactamase and two K. oxytoca hyperproducing their chromosomal K1 beta-lactamase. The MicroScan clavulanate synergy test proved to be a valuable tool for ESBL confirmation. However, this test has limitations in detecting ESBLs in Enterobacter spp. and in discriminating ESBL-related resistance from the K1 enzyme and from inherent clavulanate susceptibility in Acinetobacter spp.

Antimicrobial Properties of Garlic Oil against Human Enteric Bacteria: Evaluation of Methodologies and Comparisons with Garlic Oil Sulfides and Garlic Powder

PubMed Central

Ross, Z. M.; O'Gara, E. A.; Hill, D. J.; Sleightholme, H. V.; Maslin, D. J.

2001-01-01

The antimicrobial effects of aqueous garlic extracts are well established but those of garlic oil (GO) are little known. Methodologies for estimating the antimicrobial activity of GO were assessed and GO, GO sulfide constituents, and garlic powder (GP) were compared in tests against human enteric bacteria. Test methodologies were identified as capable of producing underestimates of GO activity. Antimicrobial activity was greater in media lacking tryptone or cysteine, suggesting that, as for allicin, GO effects may involve sulfhydryl reactivity. All bacteria tested, which included both gram-negative and -positive bacteria and pathogenic forms, were susceptible to garlic materials. On a weight-of-product basis, 24 h MICs for GO (0.02 to 5.5 mg/ml, 62 enteric isolates) and dimethyl trisulfide (0.02 to 0.31 mg/ml, 6 enteric isolates) were lower than those for a mixture of diallyl sulfides (0.63 to 25 mg/ml, 6 enteric isolates) and for GP, which also exhibited a smaller MIC range (6.25 to 12.5 mg/ml, 29 enteric isolates). Viability time studies of GO and GP against Enterobacter aerogenes showed time- and dose-dependent effects. Based upon its thiosulfinate content, GP was more active than GO against most bacteria, although some properties of GO are identified as offering greater therapeutic potential. Further exploration of the potential of GP and GO in enteric disease control appears warranted. PMID:11133485

Proteolytic and antimicrobial activity of lactic acid bacteria grown in goat milk.

PubMed

Atanasova, Jivka; Moncheva, Penka; Ivanova, Iskra

2014-11-02

We examined 62 strains and 21 trade starter cultures from the collection of LB Bulgaricum PLC for proteolytic and antimicrobial activity of lactic acid bacteria (LAB) grown in goat milk. The aim of this study was to investigate the fermentation of caseins, α-lactalbumin and β-lactoglobulin by LAB, using the o -phthaldialdehyde (OPA) spectrophotometric assay and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The proteolysis targeted mainly caseins, especially β-casein. Whey proteins were proteolyzed, essentially β-lactoglobulin. The proteolytic activity of Lactococcus lactis l598, Streptococcus thermophilus t3D1, Dt1, Lactobacillus lactis 1043 and L. delbrueckii subsp. bulgaricus b38, b122 and b24 was notably high. The proteolysis process gave rise to medium-sized peptide populations. Most of the examined strains showed antimicrobial activity against some food pathogens, such as Escherichia coli , Staphylococcus aureus , Salmonella cholere enteridis , Listeria monocytogenes , Listeria innocua and Enterobacter aerogenes . The most active producers of antimicrobial-active peptides were strains of L. delbrueckii subsp. bulgaricus and S. thermophilus , which are of practical importance. The starter cultures containing the examined species showed high proteolytic and antimicrobial activity in skimmed goat milk. The greatest antimicrobial activity of the cultures was detected against E. aerogenes . The obtained results demonstrated the significant proteolytic potential of the examined strains in goat milk and their potential for application in the production of dairy products from goat's milk. The present results could be considered as the first data on the proteolytic capacity of strains and starter cultures in goat milk for the purposes of trade interest of LB Bulgaricum PLC.

Purification and characterization of a GH43 β-xylosidase from Enterobacter sp. identified and cloned from forest soil bacteria.

PubMed

Campos, Eleonora; Negro Alvarez, María José; Sabarís di Lorenzo, Gonzalo; Gonzalez, Sergio; Rorig, Marcela; Talia, Paola; Grasso, Daniel H; Sáez, Felicia; Manzanares Secades, Paloma; Ballesteros Perdices, Mercedes; Cataldi, Angel A

2014-01-01

The use of lignocellulosic biomass for second generation biofuels requires optimization of enzymatic breakdown of plant cell walls. In this work, cellulolytic bacteria were isolated from a native and two cultivated forest soil samples. Amplification of glycosyl hydrolases was attempted by using a low stringency-degenerate primer PCR strategy, using total soil DNA and bulk DNA pooled from positive colonies as template. A set of primers was designed based on Acidothermus cellulolyticus genome, by search of conserved domains of glycosyl hydrolases (GH) families of interest. Using this approach, a fragment containing an open reading frame (ORF) with 98% identity to a putative GH43 beta-xylosidase coding gene from Enterobacter cloacae was amplified and cloned. The full protein was expressed in Escherichia coli as N-terminal or C-terminal His-tagged fusions and purified under native conditions. Only N-terminal fusion protein, His-Xyl43, presented beta-xylosidase activity. On pNPX, optimal activity was achieved at pH 6 and 40 °C and Km and Kcat values were 2.92 mM and 1.32 seg(-1), respectively. Activity was also demonstrated on xylobiose (X2), with Km 17.8 mM and Kcat 380 s(-1). These results demonstrated that Xyl43 is a functional beta-xylosidase and it is the first evidence of this activity for Enterobacter sp. Copyright © 2013 Elsevier GmbH. All rights reserved.

Biohydrogen production by dark fermentation of glycerol using Enterobacter and Citrobacter Sp.

PubMed

Maru, Biniam T; Constanti, Magda; Stchigel, Alberto M; Medina, Francesc; Sueiras, Jesus E

2013-01-01

Glycerol is an attractive substrate for biohydrogen production because, in theory, it can produce 3 mol of hydrogen per mol of glycerol. Moreover, glycerol is produced in substantial amounts as a byproduct of producing biodiesel, the demand for which has increased in recent years. Therefore, hydrogen production from glycerol was studied by dark fermentation using three strains of bacteria: namely, Enterobacter spH1, Enterobacter spH2, and Citrobacter freundii H3 and a mixture thereof (1:1:1). It was found that, when an initial concentration of 20 g/L of glycerol was used, all three strains and their mixture produced substantial amounts of hydrogen ranging from 2400 to 3500 mL/L, being highest for C. freundii H3 (3547 mL/L) and Enterobacter spH1 (3506 mL/L). The main nongaseous fermentation products were ethanol and acetate, albeit in different ratios. For Enterobacter spH1, Enterobacter spH2, C. freundii H3, and the mixture (1:1:1), the ethanol yields (in mol EtOH/mol glycerol consumed) were 0.96, 0.67, 0.31, and 0.66, respectively. Compared to the individual strains, the mixture (1:1:1) did not show a significantly higher hydrogen level, indicating that there was no synergistic effect. Enterobacter spH1 was selected for further investigation because of its higher yield of hydrogen and ethanol. Copyright © 2012 American Institute of Chemical Engineers (AIChE).

Combined physico-chemical treatments based on enterocin AS-48 for inactivation of Gram-negative bacteria in soybean sprouts.

PubMed

Cobo Molinos, Antonio; Abriouel, Hikmate; López, Rosario Lucas; Valdivia, Eva; Omar, Nabil Ben; Gálvez, Antonio

2008-08-01

Enterocin AS-48 was tested for decontamination of soybean sprouts against Gram-negative bacteria. Although treatment with bacteriocin alone had no effect on Salmonella enterica, a synergistic antimicrobial effect was detected at pH 9.0 and in combination with moderate heat treatment. Greatest inactivation was achieved for sprouts heated for 5 min at 65 degrees C in an alkaline (pH 9.0) enterocin AS-48 solution of 25 microg/ml. Bactericidal activity against S. enterica increased greatly when enterocin AS-48 was used in washing solutions in combination with several chemical compounds: EDTA, lactic acid, peracetic acid, polyphosphoric acid, sodium hypochlorite, hexadecylpyridinium chloride, propyl-p-hydroxybenzoate, and hydrocinnamic acid. The combined treatment of enterocin AS-48 and polyphosphoric acid was tested against several other Gram-negative bacteria inoculated on sprouts. The bacteria tested showed great differences in sensitivity to polyphosphoric acid, but synergism with enterocin AS-48 was confirmed in all cases. Combinations of enterocin AS-48 (25 microg/ml) and polyphosphoric acid in a concentration range of 0.1 to 2.0% significantly reduced or inhibited growth of the populations of S. enterica, Escherichia coli O157:H7, Shigella spp., Enterobacter aerogenes, Yersinia enterocolitica, Aeromonas hydrophila and Pseudomonas fluorescens in sprout samples stored at 6 degrees C and 15 degrees C. The combined treatment could therefore be applied to reduce the risks of Gram-negative pathogenic as well as spoilage bacteria on sprouts.

An Enterobacter plasmid as a new genetic background for the transposon Tn1331

PubMed Central

Alavi, Mohammad R; Antonic, Vlado; Ravizee, Adrien; Weina, Peter J; Izadjoo, Mina; Stojadinovic, Alexander

2011-01-01

Background Genus Enterobacter includes important opportunistic nosocomial pathogens that could infect complex wounds. The presence of antibiotic resistance genes in these microorganisms represents a challenging clinical problem in the treatment of these wounds. In the authors’ screening of antibiotic-resistant bacteria from complex wounds, an Enterobacter species was isolated that harbors antibiotic-resistant plasmids conferring resistance to Escherichia coli. The aim of this study was to identify the resistance genes carried by one of these plasmids. Methods The plasmids from the Enterobacter isolate were propagated in E. coli and one of the plasmids, designated as pR23, was sequenced by the Sanger method using fluorescent dyeterminator chemistry on a genetic analyzer. The assembled sequence was annotated by search of the GenBank database. Results Plasmid pR23 is composed of the transposon Tn1331 and a backbone plasmid that is identical to the plasmid pPIGDM1 from Enterobacter agglomerans. The multidrug-resistance transposon Tn1331, which confers resistance to aminoglycoside and beta lactam antibiotics, has been previously isolated only from Klebsiella. The Enterobacter plasmid pPIGDM1, which carries a ColE1-like origin of replication and has no apparent selective marker, appears to provide a backbone for propagation of Tn1331 in Enterobacter. The recognition sequence of Tn1331 transposase for insertion into pPIGDM1 is the pentanucleotide TATTA, which occurs only once throughout the length of this plasmid. Conclusion Transposition of Tn1331 into the Enterobacter plasmid pPIGDM1 enables this transposon to propagate in this Enterobacter. Since Tn1331 was previously isolated only from Klebsiella, this report suggests horizontal transfer of this transposon between the two bacterial genera. PMID:22259249

Phenotypic and molecular characterization of antimicrobial resistance in Enterobacter spp. isolates from companion animals in Japan

PubMed Central

Harada, Kazuki; Shimizu, Takae; Mukai, Yujiro; Kuwajima, Ken; Sato, Tomomi; Kajino, Akari; Usui, Masaru; Tamura, Yutaka; Kimura, Yui; Miyamoto, Tadashi; Tsuyuki, Yuzo; Ohki, Asami; Kataoka, Yasushi

2017-01-01

The emergence of antimicrobial resistance among Enterobacter spp., including resistance to extended-spectrum cephalosporins (ESC), is of great concern in both human and veterinary medicine. In this study, we investigated the prevalence of antimicrobial resistance among 60 isolates of Enterobacter spp., including E. cloacae (n = 44), E. aerogenes (n = 10), and E. asburiae (n = 6), from clinical specimens of dogs and cats from 15 prefectures in Japan. Furthermore, we characterized the resistance mechanisms harbored by these isolates, including extended-spectrum β-lactamases (ESBLs) and plasmid-mediated quinolone resistance (PMQR); and assessed the genetic relatedness of ESC-resistant Enterobacter spp. strains by multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). Antimicrobial susceptibility testing demonstrated the resistance rates to ampicillin (93.3%), amoxicillin-clavulanic acid (93.3%), cefmetazole (93.3%), chloramphenicol (46.7%), ciprofloxacin (43.3%), tetracycline (40.0%), ceftazidime (33.3%), cefotaxime (33.3%), trimethoprim/sulfamethoxazole (28.3%), gentamicin (23.3%), and meropenem (0%). Phenotypic testing detected ESBLs in 16 of 18 ESC-resistant E. cloacae isolates but not in the other species. The most frequent ESBL was CTX-M-15 (n = 8), followed by SHV-12 (n = 7), and CTX-M-3 (n = 1). As for AmpC β-lactamases, CMY-2 (n = 2) and DHA-1 (n = 2) were identified in ESC-resistant E. cloacae strains with or without ESBLs. All of the ESC-resistant E. cloacae strains also harbored one or two PMQRs, including qnrB (n = 15), aac(6’)-Ib-cr (n = 8), and qnrS (n = 2). Based on MLST and PFGE analysis, E. cloacae clones of ST591-SHV-12, ST171-CTX-M-15, and ST121-CTX-M-15 were detected in one or several hospitals. These results suggested intra- and inter-hospital dissemination of E. cloacae clones co-harboring ESBLs and PMQRs among companion animals. This is the first report on the large-scale monitoring of antimicrobial-resistant isolates

Phenotypic and molecular characterization of antimicrobial resistance in Enterobacter spp. isolates from companion animals in Japan.

PubMed

Harada, Kazuki; Shimizu, Takae; Mukai, Yujiro; Kuwajima, Ken; Sato, Tomomi; Kajino, Akari; Usui, Masaru; Tamura, Yutaka; Kimura, Yui; Miyamoto, Tadashi; Tsuyuki, Yuzo; Ohki, Asami; Kataoka, Yasushi

2017-01-01

The emergence of antimicrobial resistance among Enterobacter spp., including resistance to extended-spectrum cephalosporins (ESC), is of great concern in both human and veterinary medicine. In this study, we investigated the prevalence of antimicrobial resistance among 60 isolates of Enterobacter spp., including E. cloacae (n = 44), E. aerogenes (n = 10), and E. asburiae (n = 6), from clinical specimens of dogs and cats from 15 prefectures in Japan. Furthermore, we characterized the resistance mechanisms harbored by these isolates, including extended-spectrum β-lactamases (ESBLs) and plasmid-mediated quinolone resistance (PMQR); and assessed the genetic relatedness of ESC-resistant Enterobacter spp. strains by multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). Antimicrobial susceptibility testing demonstrated the resistance rates to ampicillin (93.3%), amoxicillin-clavulanic acid (93.3%), cefmetazole (93.3%), chloramphenicol (46.7%), ciprofloxacin (43.3%), tetracycline (40.0%), ceftazidime (33.3%), cefotaxime (33.3%), trimethoprim/sulfamethoxazole (28.3%), gentamicin (23.3%), and meropenem (0%). Phenotypic testing detected ESBLs in 16 of 18 ESC-resistant E. cloacae isolates but not in the other species. The most frequent ESBL was CTX-M-15 (n = 8), followed by SHV-12 (n = 7), and CTX-M-3 (n = 1). As for AmpC β-lactamases, CMY-2 (n = 2) and DHA-1 (n = 2) were identified in ESC-resistant E. cloacae strains with or without ESBLs. All of the ESC-resistant E. cloacae strains also harbored one or two PMQRs, including qnrB (n = 15), aac(6')-Ib-cr (n = 8), and qnrS (n = 2). Based on MLST and PFGE analysis, E. cloacae clones of ST591-SHV-12, ST171-CTX-M-15, and ST121-CTX-M-15 were detected in one or several hospitals. These results suggested intra- and inter-hospital dissemination of E. cloacae clones co-harboring ESBLs and PMQRs among companion animals. This is the first report on the large-scale monitoring of antimicrobial-resistant isolates

Pasteurella aerogenes as an Asymptomatic Bacteriuria Agent.

PubMed

Alaygut, Demet; Engin, Aynur

2018-02-01

'Asymptomatic bacteriuria' (ASB) is isolation of a specified quantitative count of bacteria in an appropriately collected urine specimen obtained from a person without symptoms or signs referable to urinary infection. Catheterized specimens are less likely to be contaminated compared with voided specimens; therefore, positive cultures of catheterized specimens are more likely to reflect true bladder bacteriuria even with low colony counts. The common pathogens for ASB are Escherichia coli, Klebsiella and Streptococcus spp. Pasteurella spp. was not previously reported as an ASB agent. ASB is important for pregnant women, children, individuals with obstructive uropathy, chronic renal failure and neutropenia, before the urologic procedures and after renal transplantation. Treatment of ASB is required for above situations. We report an 11-year-old-girl with neurogenic bladder who made clean intermittent catheterization and had Pasteurella aerogenes as an ASB agent. © The Author [2017]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Prevalence and Characterization of High Histamine-Producing Bacteria in Gulf of Mexico Fish Species.

PubMed

Bjornsdottir-Butler, Kristin; Bowers, John C; Benner, Ronald A

2015-07-01

Recent developments in detection and enumeration of histamine-producing bacteria (HPB) have created powerful molecular-based tools to better understand the presence of spoilage bacteria and conditions, resulting in increased risk of scombrotoxin fish poisoning. We examined 235 scombrotoxin-forming fish from the Gulf of Mexico for the presence of high HPB. Photobacterium damselae subsp. damselae was the most prevalent HPB (49%), followed by Morganella morganii (14%), Enterobacter aerogenes (4%), and Raoultella planticola (3%). The growth characteristics and histamine production capabilities of the two most prevalent HPB were further examined. M. morganii and P. damselae had optimum growth at 35°C and 30 to 35°C and 0 to 2% and 1 to 3% NaCl, respectively. P. damselae produced significantly (P < 0.001) higher histamine than M. morganii in inoculated mahimahi and Spanish mackerel incubated at 30°C for 24 h, but histamine production was not significantly different between the two HPB in inoculated tuna, possibly due to differences in muscle composition and salt content. Results in this study showed that P. damselae was the most prevalent high HPB in Gulf of Mexico fish. In addition, previously reported results using the traditional Niven's method may underreport the prevalence of P. damselae. Molecular-based methods should be used in addition to culture-based methods to enhance detection and enumeration of HPB.

Enterobacter mori sp. nov., associated with bacterial wilt on Morus alba L.

PubMed

Zhu, Bo; Lou, Miao-Miao; Xie, Guan-Lin; Wang, Guo-Fen; Zhou, Qin; Wang, Fang; Fang, Yuan; Su, Ting; Li, Bin; Duan, Yong-Pin

2011-11-01

Two isolates of mulberry-pathogenic bacteria isolated from diseased mulberry roots were investigated in a polyphasic taxonomic study. Comparative 16S rRNA gene sequence analysis combined with rpoB gene sequence analysis allocated strains R18-2(T) and R3-3 to the genus Enterobacter, with Enterobacter asburiae, E. amnigenus, E. cancerogenus, E. cloacae subsp. cloacae, E. cloacae subsp. dissolvens and E. nimipressuralis as their closest relatives. Cells of the isolates were Gram-negative, facultatively anaerobic rods, 0.3-1.0 µm wide and 0.8-2.0 µm long, with peritrichous flagella, showing a DNA G+C content of 55.1 ± 0.5 mol%. Calculation of a similarity index based on phenotypic features and fatty acid methyl ester (FAME) analysis suggested that these isolates are members of E. cancerogenus or E. asburiae or a closely related species. Biochemical data revealed that the isolates could be differentiated from their nearest neighbours by the presence of lysine decarboxylase activity and their ability to utilize d-arabitol. DNA-DNA relatedness also distinguished the two isolates from phylogenetically closely related Enterobacter strains. Based on these data, it is proposed that the isolates represent a novel species of the genus Enterobacter, named Enterobacter mori sp. nov. The type strain is R18-2(T) ( = CGMCC 1.10322(T) = LMG 25706(T)).

Cellulose synthesized by Enterobacter sp. FY-07 under aerobic and anaerobic conditions.

PubMed

Ma, Ting; Ji, Kaihua; Wang, Wei; Wang, Jinghong; Li, Zhaoyu; Ran, Haitao; Liu, Bin; Li, Guoqiang

2012-12-01

Enterobacter sp. FY-07 can produce bacterial cellulose (BC) under aerobic and anaerobic conditions. In static cultivation at 30 °C for 72 h under anoxic, oxygen-limited and aerated conditions, cellulose production exceeded 5 g/l, which indicated that oxygen was not essential for production of BC by Enterobacter sp. FY-07. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) analysis showed that the microstructure of the BC was similar to that produced by aerobic bacteria such as Gluconacetobacter xylinum BCRC12335 and Acetobacter sp. V6. The crystallinity index of the BC was 63.3%. Water-holding capacity (approximately 11000%) and rehydration ratio (24.4%) were superior to those reported for BC produced by the aerobic bacteria G. xylinum BCRC12335 and Acetobacter sp. V6. These results will facilitate static submerged fermentation for the production of BC. Copyright © 2012 Elsevier Ltd. All rights reserved.

My 40-Year History with Cronobacter/Enterobacter sakazakii – Lessons Learned, Myths Debunked, and Recommendations

PubMed Central

Farmer, John J.

2015-01-01

Much has been learned about organism in the Cronobacter/Enterobacter sakazakii complex since I first named and described Enterobacter sakazakii in 1980. However, there are still wide knowledge gaps. One of the most serious is that are still many uncertainties associated with assessing the public health risk posed by these bacteria, particularly in neonatal meningitis. Over the last few decades, Cronobacter contamination of commercial powdered infant formula products has apparently been reduced, but it is still an ongoing problem. The powdered infant formula industry still cannot produce powdered formula that is free of bacterial contamination with Cronobacter, other Enterobacteriaceae, other pathogenic bacteria, and other microorganisms. Until this happens, infants and other will be at risk of becoming infected when they ingest contaminated formula. PMID:26640778

Prevalence and characterization of multidrug-resistant zoonotic Enterobacter spp. in poultry of Bangladesh.

PubMed

Nandi, Shuvro Prokash; Sultana, Munawar; Hossain, M Anwar

2013-05-01

Poultry and poultry products are major contributors of zoonotic pathogens. Limited data are available on Enterobacter spp. as a potent zoonotic pathogen in poultry. The present study is a first endeavor on the emergence of multidrug-resistant zoonotic Enterobacter spp. and its prevalence arising from poultry in Bangladesh. Cloacal swabs from poultry samples of five different farms at Savar, Dhaka, Bangladesh were collected and from 106 isolates, 18 presumptive Enterobacter spp. were obtained. Antibiogram using 19 used antibiotics belonging to 15 major groups revealed that all of the 18 isolates were completely resistant to penicillin and rifampicin, but differed in their drug resistance pattern against ampicillin (94.4%), clindamycin (94.4%), erythromycin (94.4%), vancomycin (88.9%), sulfonamides (72.2%), imipenem (66.6%), streptomycin (55.6%), nitrofurantoin (33.3%), doxycycline (33.3%), tetracyclines (33.3%), cefepime (11.1%), and gentamicin (5.6%). All Enterobacter spp. were found to be plasmid free, implying that multidrug-resistant properties are chromosomal borne. The vanA and sulI were detected by polymerase chain reaction assay in 17 and 13 isolates, respectively. Amplified ribosomal DNA restriction analysis and randomly amplified polymorphic DNA distributed the 18 multidrug-resistant Enterobacter spp. into three genotypes. Phylogenetic analysis of the representatives of the three genotypes using partial 16S rRNA gene sequence (approximately 900 bp) showed that the genotypically diverse groups belonged to Enterobacter hormaechei, E. cloacae, and E. cancerogenus, respectively. The clinical significance of the close relative Enterobacter spp. is indicative of their zoonotic potential. Therefore, urgent intervention is required to limit the emergence and spread of these bacteria in poultry feed as well as prudent use of antibiotics among poultry farmers in Bangladesh.

Antimicrobial properties of black grape (Vitis vinifera L.) peel extracts against antibiotic-resistant pathogenic bacteria and toxin producing molds.

PubMed

Yadav, Devbrat; Kumar, Arvind; Kumar, Pramod; Mishra, Diwaker

2015-01-01

Black grape peel possesses a substantial amount of polyphenolic antimicrobial compounds that can be used for controlling the growth of pathogenic microorganisms. The purpose of this study was to assess antibacterial and antifungal activity of black grape peel extracts against antibiotic-resistant pathogenic bacteria and toxin producing molds, respectively. Peel of grape was subjected to polyphenolic extraction using different solvents viz., water, ethanol, acetone, and methanol. Antibiotic-resistant strains of Staphylococcus aureus, Enterococcus faecalis, Enterobacter aerogenes, Salmonella typhimurium, and Escherichia coli were screened for the antibacterial activity of different grape extracts. Antibacterial activity was analyzed using agar well diffusion method. Penicillium chrysogenum, Penicillium expansum, Aspergillus niger and Aspergillus versicolor were screened for the antifungal activity. Antifungal activity was determined by counting nongerminated spores in the presence of peel extracts. As compared to other solvent extracts, methanol extracts possessed high antibacterial and antifungal activity. S. typhimurium and E. coli showed complete resistance against antibacterial action at screened concentrations of grape peel extracts. Maximum zone of inhibition was found in case of S. aureus, i.e., 22 mm followed by E. faecalis and E. aerogenes, i.e., 18 and 21 mm, respectively, at 1080 mg tannic acid equivalent (TAE)/ml. The maximum and minimum percent of growth inhibition was shown by P. expansum and A. niger as 73% and 15% at 1080 TAE/ml concentration of grape peel extract, respectively. Except S. typhimurium and E. coli, growth of all bacterial and mold species were found to be significantly (P < 0.05) inhibited by all the solvent extracts.

Bioprospecting of lipolytic microorganisms obtained from industrial effluents.

PubMed

Peil, Greice H S; Kuss, Anelise V; Rave, Andrés F G; Villarreal, José P V; Hernandes, Yohana M L; Nascente, Patrícia S

2016-01-01

The lipases have ability to catalyze diverse reactions and are important in different biotechnological applications. The aim of this work was to isolate and characterize microorganisms that produce lipases, from different food industry effluents localized in Pelotas, RS/Brazil. Bacteria were identified using Gram stain and biochemical tests (Vitek 2(r)). Fungi were identified according to macro and micromorphology characteristics. The extracellular lipase production was evaluated using the Rhodamine B test and the enzymatic activity by titration. Twenty-one bacteria were isolated and identified as Klebsiella pneumoniae ssp. pneumoniae, Serratia marcescens, Enterobacter aerogenes, Raoultella ornithinolytica and Raoultella planticola. Were characterized isolated filamentous fungi by the following genera: Alternaria sp., Fusarium sp., Geotrichum sp., Gliocladium sp., Mucor sp., Paecilomyces sp. and Trichoderma sp. Extracellular lipase production was observed in 71.43% of the bacteria and 57.14% of the fungi. The bacterium that presented better promising enzymatic activity was E. aerogenes (1.54 U/ml) however between fungi there was not significant difference between the four isolates. This study indicated that microorganisms lipase producers are present in the industrial effluents, as well as these enzymes have potential of biodegradation of lipid compounds.

Synthesis and antimicrobial evaluation of ester-linked 1,4-disubstituted 1,2,3-triazoles with a furyl/thienyl moiety.

PubMed

Kaushik, C P; Luxmi, Raj; Singh, Dharmendra; Kumar, Ashwani

2017-02-01

Twenty ester-linked 1,4-disubstituted 1,2,3-triazoles having a furyl/thienyl moiety have been synthesized from heteroaryl prop-2-yn-1-yl carboxylate and aromatic azides via a Cu(I) catalyzed 1,3-dipolar cycloaddition. All the synthesized compounds were characterized by FTIR, [Formula: see text]H NMR, [Formula: see text]C NMR spectroscopy and HRMS. Synthesized triazoles were tested in vitro for antimicrobial evaluation against Gram-negative bacteria-Escherichia coli, Enterobacter aerogenes and Klebsiella pneumoniae; Gram-positive bacteria-Staphylococcus aureus and two fungal strains-Candida albicans and Aspergillus niger, reflecting moderate to good activity. The structure of compound 6f was also confirmed by X-ray crystallography (CCDC 1469326).

KPC and VIM producing Enterobacter cloacae strain from a hospital in northeastern Venezuela.

PubMed

Martínez, Dianny; Marcano, Daniel; Rodulfo, Hectorina; Salgado, Nurys; Cuaical, Nirvia; Rodriguez, Lucy; Caña, Luisa; Medina, Belkis; Guzman, Militza; De Donato, Marcos

2015-06-01

An 83-year-old male patient is admitted to the central hospital in Cumana, Venezuela with severe urinary infection, history of hospitalizaions and prolonged antimicrobial treatments. A strain of Enterobacter cloacae was isolated showing resistance to multiple types of antibiotics (only sensitive to gentamicin), with phenotype of serine- and metallo-carbapenemases. Both, bla(VIM-2) and bla(KPC) genes were detected in the isolate. This is the first report of an Enterobacteriaceae species producing both KPC carbapenemase and VIM metallo carbapenemase in Venezuela. This finding has a great clinical and epidemiological impact in the region, because of the feasibility of transferring these genes, through mobile elements to other strains of Enterobacter and to other infection-causing species of bacteria.

Antibacterial activities of the methanol extracts of Albizia adianthifolia, Alchornea laxiflora, Laportea ovalifolia and three other Cameroonian plants against multi-drug resistant Gram-negative bacteria.

PubMed

Tchinda, Cedric F; Voukeng, Igor K; Beng, Veronique P; Kuete, Victor

2017-05-01

In the last 10 years, resistance in Gram-negative bacteria has been increasing. The present study was designed to evaluate the in vitro antibacterial activities of the methanol extracts of six Cameroonian medicinal plants Albizia adianthifolia , Alchornea laxiflora , Boerhavia diffusa , Combretum hispidum , Laportea ovalifolia and Scoparia dulcis against a panel of 15 multidrug resistant Gram-negative bacterial strains. The broth microdilution was used to determine the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of the extracts. The preliminary phytochemical screening of the extracts was conducted according to the reference qualitative phytochemical methods. Results showed that all extracts contained compounds belonging to the classes of polyphenols and triterpenes, other classes of chemicals being selectively distributed. The best antibacterial activities were recorded with bark and root extracts of A. adianthifolia as well as with L. ovalifolia extract, with MIC values ranging from 64 to 1024 μg/mL on 93.3% of the fifteen tested bacteria. The lowest MIC value of 64 μg/mL was recorded with A. laxiflora bark extract against Enterobacter aerogenes EA289. Finally, the results of this study provide evidence of the antibacterial activity of the tested plants and suggest their possible use in the control of multidrug resistant phenotypes.

Genome Sequence of the Plant Growth Promoting Endophytic Bacterium Enterobacter sp. 638

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taghavi, S.; van der Lelie, D.; Hoffman, A.

2010-05-13

exploited to improve establishment and sustainable production of poplar as an energy feedstock on marginal, non-agricultural soils using endophytic bacteria as growth promoting agents. Poplar is considered as the model tree species for the production of lignocellulosic biomass destined for biofuel production. The plant growth promoting endophytic bacterium Enterobacter sp. 638 can improve the growth of poplar on marginal soils by as much as 40%. This prompted us to sequence the genome of this strain and, via comparative genomics, identify functions essential for the successful colonization and endophytic association with its poplar host. Analysis of the genome sequence, combined with metabolite analysis and quantitative PCR, pointed to a remarkable interaction between Enterobacter sp. 638 and its poplar host with the endophyte responsible for the production of a phytohormone, and a precursor for another that poplar is unable to synthesize, and where the production of the plant growth promoting compounds depended on the presence of plant synthesized compounds, such as sucrose, in the growth medium. Our results provide the basis to better understanding the synergistic interactions between poplar and Enterobacter sp. 638. This information can be further exploited to improve establishment and sustainable production of poplar on marginal, non-agricultural soils using endophytic bacteria such as Enterobacter sp. 638 as growth promoting agents.« less

Enterobacter Strains Might Promote Colon Cancer.

PubMed

Yurdakul, Dilşad; Yazgan-Karataş, Ayten; Şahin, Fikrettin

2015-09-01

Many studies have been performed to determine the interaction between bacterial species and cancer. However, there has been no attempts to demonstrate a possible relationship between Enterobacter spp. and colon cancer so far. Therefore, in the present study, it is aimed to investigate the effects of Enterobacter strains on colon cancer. Bacterial proteins were isolated from 11 Enterobacter spp., one Morganella morganii, and one Escherichia coli strains, and applied onto NCM460 (Incell) and CRL1790 (ATCC) cell lines. Cell viability and proliferation were determined in MTS assay. Flow Cytometry was used to detect CD24 level and apoptosis. Real-Time PCR studies were performed to determine NFKB and Bcl2 expression. Graphpad Software was used for statistical analysis. The results showed that proteins, isolated from the Enterobacter spp., have significantly increased cell viability and proliferation, while decreasing the apoptosis of the cell lines tested. The data in the present study indicated that Enterobacter strains might promote colon cancer. Moreover, Enterobacter spp. could be a clinically important factor for colon cancer initiation and progression. Studies can be extended on animal models in order to develop new strategies for treatment.

Two symbiotic bacteria of the entomopathogenic nematode Heterorhabditis spp. against Galleria mellonella.

PubMed

Liao, Chunli; Gao, Along; Li, Bingbing; Wang, Mengjun; Shan, Linna

2017-03-01

The entomopathogenic nematode Heterorhabditis spp. is considered a promising agent in the biocontrol of injurious insects of agriculture. However, different symbiotic bacteria associated with the nematode usually have different specificity and virulence toward their own host. In this study, two symbiotic bacteria, LY2W and NK, were isolated from the intestinal canals of two entomopathogenic nematode Heterorhabditis megidis 90 (PDSj1 and PDSj2) from Galleria mellonela, separately. To determine their species classification, we carried out some investigations on morphology, culture, biochemistry, especially 16S rDNA sequence analyses. As a result, both of them belong to Enterobacter spp., showing the closest relatedness with Enterobacter gergoviae (LY2W) and Enterobacter cloacae (NK), respectively. Moreover, the toxicity to Galleria mellonella was examined using both the metabolites and washed cells (primary and secondary) of these two strains. The results indicated both metabolites and cells of the primary-type bacteria could cause high mortalities (up to 97%) to Galleria mellonella, while those of the primary-type bacteria only killed 20%. These findings would provide new symbiotic bacteria and further references for biological control of the agricultural pest. Copyright © 2016 Elsevier Ltd. All rights reserved.

Enterobacter and Klebsiella species isolated from fresh vegetables marketed in Valencia (Spain) and their clinically relevant resistances to chemotherapeutic agents.

PubMed

Falomir, María Pilar; Rico, Hortensia; Gozalbo, Daniel

2013-12-01

Occurrence of antibiotic-resistant pathogenic or commensal enterobacteria in marketed agricultural foodstuffs may contribute to their incorporation into the food chain and constitutes an additional food safety concern. In this work, we have determined the clinically relevant resistances to 11 common chemotherapeutic agents in Enterobacter and Klebsiella isolates from fresh vegetables from various sources (supermarkets and greengrocers' shops in Valencia, Spain). A total of 96 isolates were obtained from 160 vegetables analyzed (50% positive samples): 68 Enterobacter isolates (59 E. cloacae, two E. aerogenes, two E. cancerogenus, one E. gergoviae, and four E. sakazakii, currently Cronobacter spp.), and 28 Klebsiella isolates (19 K. oxytoca and 9 K. pneumoniae). Only seven isolates were susceptible to all agents tested, and no resistances to ceftazidime, ciprofloxacin, gentamicin, and chloramphenicol were detected. Most isolates were resistant to amoxicillin/clavulanic acid (74 [58 Enterobacter and 16 Klebsiella]) or to ampicillin (80 [55/25]). Other resistances were less frequent: nitrofurantoin (13 isolates [12/1]), tetracycline (6 [5/1]), co-trimoxazole (3 [3/0]), cefotaxime (1 [1/0]), and streptomycin (2 [1/1]). Multiresistant isolates to two (56 [41/15]), three (10 E. cloacae isolates), four (one E. cloacae and one K. pneumoniae isolate), and five (two E. cloacae isolates) chemotherapeutic agents were also detected. The presence of potential pathogens points to marketed fresh produce, which often is eaten raw, as a risk factor for consumer health. In addition, these results support the usefulness of these bacterial species as indicators of the spreading of antibiotic resistances into the environment, particularly in the food chain, and suggest their role as carriers of resistance determinants from farms to consumers, which may constitute an additional "silent" food safety concern. Therefore, there is a need to improve the hygienic quality of marketed fresh

[Post-marketing surveillance of antibacterial activities of cefozopran against various clinical isolates--II. Gram-negative bacteria].

PubMed

Igari, Jun; Oguri, Toyoko; Hiramatsu, Nobuyoshi; Akiyama, Kazumitsu; Koyama, Tsuneo

2003-10-01

As a post-marketing surveillance, the in vitro antibacterial activities of cefozopran (CZOP), an agent of cephems, against various clinical isolates were yearly evaluated and compared with those of other cephems, oxacephems, carbapenems, monobactams, and penicillins. Changes in CZOP susceptibility among bacteria were also evaluated with the bacterial resistance ratio calculated from the breakpoint MIC. Twenty-five species (4,154 strains) of Gram-negative bacteria were isolated from the clinical materials annually collected from 1996 to 2001, and consisted of Moraxella (Branhamella) catarrhalis, Haemophilus influenzae, Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter cloacae, Enterobacter aerogenes, Serratia marcescens, Serratia liquefaciens, Citrobacter freundii, Citrobacter koseri, Proteus mirabilis, Proteus vulgaris, Morganella morganii, Providencia spp., Pseudomonas aeruginosa, Pseudomonas fluorescens, Pseudomonas putida, Acinetobacter baumannii, Acinetobacter Iwoffii, Burkholderia cepacia, Stenotrophomonas maltophilia, Bacteroides fragilis group, and Prevotella/Porphyromonas. CZOP preserved its antibacterial activity against M. (B.) catarrhalis (MIC90: 4 micrograms/mL) and showed comparable activity to carbapenems against H. influenzae (MIC90: 1 microgram/mL). The antibacterial activity of CZOP against E. coli was preferable (MIC90: 0.125 microgram/mL) and comparable to those of cefpirome (CPR), cefepime (CFPM), and imipenem (IPM). The MIC90 of CZOP against K. pneumoniae and K. oxytoca was 1 and 0.25 microgram/mL, respectively. The MIC90 of CZOP against E. cloacae increased during 6 years (32 to 128 micrograms/mL). The antibacterial activity of CZOP against E. aerogenes was preferable (MIC90: 1 microgram/mL). The antibacterial activities of CZOP against S. marcescens and S. liquefaciens were relatively potent (MIC90: 0.5 and 0.25 microgram/mL) and comparable to those of CPR, CFPM, and carumonam. CZOP preserved comparable antibacterial

Phenotypic changes contributing to Enterobacter gergoviae biocide resistance.

PubMed

Périamé, M; Philippe, N; Condell, O; Fanning, S; Pagès, J-M; Davin-Regli, A

2015-08-01

Enterobacter gergoviae is a recurrent contaminant of cosmetic and hygiene products. To understand how this bacterium adapts to biocides, we studied Ent. gergoviae CIP 76.01 and its triclosan and Methylisothiazolinone-chloromethylisothiazolinone (MIT-CMIT) tolerant isogenic mutants. They were compared with others also isolated from contaminated cosmetics. Phenotypic differences were noted and these included changes in the bacterial envelope and flagella along with differences in motility, and biofilm growth rates. Triclosan and MIT-CMIT derivatives expressed flagella and other MIT-CMIT derivatives exhibited some external appendages. Those bacteria expressing a high-level minimal inhibitory concentration to MIT-CMIT, expressed a strong biofilm formation. No differential phenotypes were noted for carbon source utilisation. Enterobacter gergoviae demonstrated a diverse response to both of these preservatives contained in cosmetic preparations, depending on their concentrations. Interestingly, this adaptive response is associated with modifications of filament structure-related proteins contributing to increase the organism motility and the production of biofilm. Recurrent contaminations of cosmetics products by Ent. gergoviae, needed a better understanding concerning the bacterial adaptation to preservative agents, with particular concern to triclosan and MIT-CMIT. We demonstrated that bacteria response is associated to various mechanisms represented by expression of external appendages (pili or fimbriae) that control cell motility and biofilm formation and evolving as the concentration of biocides adaptation increased. Such mechanisms which are not chemical specific can also promote a cross-resistance to other biocidal agents. The characterization of Ent. gergoviae adaptability to biocides allows industry to adjust the ranges of concentrations and composition of preservatives in formula. © 2015 The Society for Applied Microbiology.

Detection of Plasmid-Mediated Quinolone Resistance Genes in Clinical Isolates of Enterobacter spp. in Spain ▿

PubMed Central

Cano, M. E.; Rodríguez-Martínez, J. M.; Agüero, J.; Pascual, A.; Calvo, J.; García-Lobo, J. M.; Velasco, C.; Francia, M. V.; Martínez-Martínez, L.

2009-01-01

We have studied by PCR and DNA sequencing the presence of the qnrA, qnrB, qnrS, aac(6′)-Ib-cr, qepA, intI1, and ISCR1 genes in 200 clinical isolates of Enterobacter cloacae (n = 153) and E. aerogenes (n = 47) consecutively collected between January 2004 and October 2005 in two hospitals located in Santander (northern Spain) and Seville (southern Spain). Mutations in the quinolone resistance-determining region of gyrA and parC also were investigated in organisms containing plasmid-mediated quinolone resistance genes. The isolates had different resistant phenotypes, including AmpC hyperproduction, extended-spectrum β-lactamase production, resistance or decreased susceptibility to quinolones, and/or resistance to aminoglycosides. Among the 116 E. cloacae isolates from Santander, qnrS1, qnrB5, qnrB2, and aac(6′)-Ib-cr were detected in 22 (19%), 1 (0.9%), 1 (0.9%), and 3 (2.6%) isolates, respectively. Twenty-one, 17, and 2 qnrS1-positive isolates also contained blaLAP-1, intI1, and ISCR1, respectively. A qnrB7-like gene was detected in one E. aerogenes isolate from Santander. No plasmid-mediated quinolone resistance gene was detected in the isolates from Seville. The qnrS1-containing isolates corresponded to four pulsed-field gel electrophoresis patterns and showed various levels of resistance to quinolones. Six isolates were susceptible to nalidixic acid and presented reduced susceptibility to ciprofloxacin. The qnrS1 gene was contained in a conjugative plasmid of ca. 110 kb, and when the plasmid was transferred to recipient strains that did not have a specific mechanism of quinolone resistance, the ciprofloxacin MICs ranged from 0.047 to 0.125 μg/ml. PMID:19386836

Interspecific reconstitution of maltose transport and chemotaxis in Escherichia coli with maltose-binding protein from various enteric bacteria.

PubMed Central

Dahl, M K; Manson, M D

1985-01-01

In Escherichia coli, the periplasmic maltose-binding protein (MBP), the product of the malE gene, is the primary recognition component of the transport system for maltose and maltodextrins. It is also the maltose chemoreceptor, in which capacity it interacts with the signal transducer Tar (taxis to aspartate and some repellents). In studies of the maltose system in other members of the family Enterobacteriaceae, we found that MBP is produced by Salmonella typhimurium, Klebsiella pneumoniae, Enterobacter aerogenes, and Serratia marcescens. MBP from all of these species cross-reacted with antibody against the E. coli protein and had a similar molecular weight (about 40,000). The Shigella flexneri and Proteus mirabilis strains we examined did not synthesize MBP. The isoelectric points of MBP from different species varied from the acid extreme of E. coli (4.8) to the basic extreme of E. aerogenes (8.9). All species with MBP transported maltose with high affinity, although the Vmax for K. pneumoniae was severalfold lower than that for the other species. Maltose chemotaxis was observed only in E. coli and E. aerogenes. In S. typhimurium LT2, Tar was completely inactive in maltose taxis, although it signaled normally in response to aspartate. MBP isolated from all five species could be used to reconstitute maltose transport and taxis in a delta malE strain of E. coli after permeabilization of the outer membrane with calcium. Images PMID:3905762

Bacteria in midguts of field-collected Anopheles albimanus block Plasmodium vivax sporogonic development.

PubMed

Gonzalez-Ceron, Lilia; Santillan, Frida; Rodriguez, Mario H; Mendez, Domingo; Hernandez-Avila, Juan E

2003-05-01

Bacterial infections were investigated in midguts of insectary and field-collected Anopheles albimanus Weidemann from southern Mexico. Serratia marcescens, Enterobacter cloacae and Enterobacter amnigenus 2, Enterobacter sp., and Serratia sp. were isolated in field samples obtained in 1998, but only Enterobacter sp. was recovered in field samples of 1997 and no bacteria were isolated from insectary specimens. These bacteria were offered along with Plasmodium vivax infected blood to aseptic insectary An. albimanus, and the number of infected mosquitoes as well as the oocyst densities assessed after 7d. Plasmodium vivax infections in mosquitoes co-infected with En. amnigenus 2, En. cloacae, and S. marcensces were 53, 17, and 210 times, respectively, lower than in control mosquitoes, and the mean oocyst density in mosquitoes co-infected with En. cloacae was 2.5 times lower than in controls. Mortality was 13 times higher in S. marcensces-infected mosquitoes compared with controls. The overall midgut bacterial infection in mosquito field populations may influence P. vivax transmission, and could contribute to explain the annual variations in malaria incidence observed in the area.

High frequency of silver resistance genes in invasive isolates of Enterobacter and Klebsiella species.

PubMed

Sütterlin, S; Dahlö, M; Tellgren-Roth, C; Schaal, W; Melhus, Å

2017-07-01

Silver-based products have been marketed as an alternative to antibiotics, and their consumption has increased. Bacteria may, however, develop resistance to silver. To study the presence of genes encoding silver resistance (silE, silP, silS) over time in three clinically important Enterobacteriaceae genera. Using polymerase chain reaction (PCR), 752 bloodstream isolates from the years 1990-2010 were investigated. Age, gender, and ward of patients were registered, and the susceptibility to antibiotics and silver nitrate was tested. Clonality and single nucleotide polymorphism were assessed with repetitive element sequence-based PCR, multi-locus sequence typing, and whole-genome sequencing. Genes encoding silver resistance were detected most frequently in Enterobacter spp. (48%), followed by Klebsiella spp. (41%) and Escherichia coli 4%. Phenotypical resistance to silver nitrate was found in Enterobacter (13%) and Klebsiella (3%) isolates. The lowest carriage rate of sil genes was observed in blood isolates from the neonatology ward (24%), and the highest in blood isolates from the oncology/haematology wards (66%). Presence of sil genes was observed in international high-risk clones. Sequences of the sil and pco clusters indicated that a single mutational event in the silS gene could have caused the phenotypic resistance. Despite a restricted consumption of silver-based products in Swedish health care, silver resistance genes are widely represented in clinical isolates of Enterobacter and Klebsiella species. To avoid further selection and spread of silver-resistant bacteria with a high potential for healthcare-associated infections, the use of silver-based products needs to be controlled and the silver resistance monitored. Copyright © 2017 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Enterobacter cloacae complex: clinical impact and emerging antibiotic resistance.

PubMed

Mezzatesta, Maria Lina; Gona, Floriana; Stefani, Stefania

2012-07-01

Species of the Enterobacter cloacae complex are widely encountered in nature, but they can act as pathogens. The biochemical and molecular studies on E. cloacae have shown genomic heterogeneity, comprising six species: Enterobacter cloacae, Enterobacter asburiae, Enterobacter hormaechei, Enterobacter kobei, Enterobacter ludwigii and Enterobacter nimipressuralis, E. cloacae and E. hormaechei are the most frequently isolated in human clinical specimens. Phenotypic identification of all species belonging to this taxon is usually difficult and not always reliable; therefore, molecular methods are often used. Although the E. cloacae complex strains are among the most common Enterobacter spp. causing nosocomial bloodstream infections in the last decade, little is known about their virulence-associated properties. By contrast, much has been published on the antibiotic-resistance features of these microorganisms. In fact, they are capable of overproducing AmpC β-lactamases by derepression of a chromosomal gene or by the acquisition of a transferable ampC gene on plasmids conferring the antibiotic resistance. Many other resistance determinants that are able to render ineffective almost all antibiotic families have been recently acquired. Most studies on antimicrobial susceptibility are focused on E. cloacae, E. hormaechei and E. asburiae; these studies reported small variations between the species, and the only significant differences had no discriminating features.

Multidrug-Resistant CTX-M-(15, 9, 2)- and KPC-2-Producing Enterobacter hormaechei and Enterobacter asburiae Isolates Possessed a Set of Acquired Heavy Metal Tolerance Genes Including a Chromosomal sil Operon (for Acquired Silver Resistance).

PubMed

Andrade, Leonardo N; Siqueira, Thiago E S; Martinez, Roberto; Darini, Ana Lucia C

2018-01-01

Bacterial resistance to antibiotics is concern in healthcare-associated infections. On the other hand, bacterial tolerance to other antimicrobials, like heavy metals, has been neglected and underestimated in hospital pathogens. Silver has long been used as an antimicrobial agent and it seems to be an important indicator of heavy metal tolerance. To explore this perspective, we searched for the presence of acquired silver resistance genes ( sil operon: silE, silS, silR, silC, silF, silB, silA , and silP ) and acquired extended-spectrum cephalosporin and carbapenem resistance genes ( bla CTX-M and bla KPC ) in Enterobacter cloacae Complex (EcC) ( n = 27) and Enterobacter aerogenes ( n = 8) isolated from inpatients at a general hospital. Moreover, the genetic background of the silA (silver-efflux pump) and the presence of other acquired heavy metal tolerance genes, pcoD (copper-efflux pump), arsB (arsenite-efflux pump), terF (tellurite resistance protein), and merA (mercuric reductase) were also investigated. Outstandingly, 21/27 (78%) EcC isolates harbored silA gene located in the chromosome. Complete sil operon was found in 19/21 silA -positive EcC isolates. Interestingly, 8/20 (40%) E. hormaechei and 5/6 (83%) E. asburiae co-harbored silA/pcoD genes and bla CTX-M-(15,2,or9) and/or bla KPC-2 genes. Frequent occurrences of arsB, terF , and merA genes were detected, especially in silA/pcoD -positive, multidrug-resistant (MDR) and/or CTX-M-producing isolates. Our study showed co-presence of antibiotic and heavy metal tolerance genes in MDR EcC isolates. In our viewpoint, there are few studies regarding to bacterial heavy metal tolerance and we call attention for more investigations and discussion about this issue in different hospital pathogens.

Multidrug-Resistant CTX-M-(15, 9, 2)- and KPC-2-Producing Enterobacter hormaechei and Enterobacter asburiae Isolates Possessed a Set of Acquired Heavy Metal Tolerance Genes Including a Chromosomal sil Operon (for Acquired Silver Resistance)

PubMed Central

Andrade, Leonardo N.; Siqueira, Thiago E. S.; Martinez, Roberto; Darini, Ana Lucia C.

2018-01-01

Bacterial resistance to antibiotics is concern in healthcare-associated infections. On the other hand, bacterial tolerance to other antimicrobials, like heavy metals, has been neglected and underestimated in hospital pathogens. Silver has long been used as an antimicrobial agent and it seems to be an important indicator of heavy metal tolerance. To explore this perspective, we searched for the presence of acquired silver resistance genes (sil operon: silE, silS, silR, silC, silF, silB, silA, and silP) and acquired extended-spectrum cephalosporin and carbapenem resistance genes (blaCTX−M and blaKPC) in Enterobacter cloacae Complex (EcC) (n = 27) and Enterobacter aerogenes (n = 8) isolated from inpatients at a general hospital. Moreover, the genetic background of the silA (silver-efflux pump) and the presence of other acquired heavy metal tolerance genes, pcoD (copper-efflux pump), arsB (arsenite-efflux pump), terF (tellurite resistance protein), and merA (mercuric reductase) were also investigated. Outstandingly, 21/27 (78%) EcC isolates harbored silA gene located in the chromosome. Complete sil operon was found in 19/21 silA-positive EcC isolates. Interestingly, 8/20 (40%) E. hormaechei and 5/6 (83%) E. asburiae co-harbored silA/pcoD genes and blaCTX−M−(15,2,or9) and/or blaKPC−2 genes. Frequent occurrences of arsB, terF, and merA genes were detected, especially in silA/pcoD-positive, multidrug-resistant (MDR) and/or CTX-M-producing isolates. Our study showed co-presence of antibiotic and heavy metal tolerance genes in MDR EcC isolates. In our viewpoint, there are few studies regarding to bacterial heavy metal tolerance and we call attention for more investigations and discussion about this issue in different hospital pathogens. PMID:29628916

How β-Lactam Antibiotics Enter Bacteria: A Dialogue with the Porins

PubMed Central

Molitor, Alexander; Bolla, Jean-Michel; Bessonov, Andrey N.; Winterhalter, Mathias; Pagès, Jean-Marie

2009-01-01

Background Multi-drug resistant (MDR) infections have become a major concern in hospitals worldwide. This study investigates membrane translocation, which is the first step required for drug action on internal bacterial targets. β-lactams, a major antibiotic class, use porins to pass through the outer membrane barrier of Gram-negative bacteria. Clinical reports have linked the MDR phenotype to altered membrane permeability including porin modification and efflux pump expression. Methodology/Principal Findings Here influx of β-lactams through the major Enterobacter aerogenes porin Omp36 is characterized. Conductance measurements through a single Omp36 trimer reconstituted into a planar lipid bilayer allowed us to count the passage of single β-lactam molecules. Statistical analysis of each transport event yielded the kinetic parameters of antibiotic travel through Omp36 and distinguishable translocation properties of β-lactams were quantified for ertapenem and cefepime. Expression of Omp36 in an otherwise porin-null bacterial strain is shown to confer increases in the killing rate of these antibiotics and in the corresponding bacterial susceptibility. Conclusions/Significance We propose the idea of a molecular “passport” that allows rapid transport of substrates through porins. Deciphering antibiotic translocation provides new insights for the design of novel drugs that may be highly effective at passing through the porin constriction zone. Such data may hold the key for the next generation of antibiotics capable of rapid intracellular accumulation to circumvent the further development MDR infections. PMID:19434239

Acid Pretreatment of Sago Wastewater for Biohydrogen Production

NASA Astrophysics Data System (ADS)

Illi Mohamad Puad, Noor; Rahim, Nurainin Farhan Abd; Suhaida Azmi, Azlin

2018-03-01

Biohydrogen has been recognized to be one of the future renewable energy sources and has the potential in solving the greenhouse effects. In this study, Enterobacter aerogenes (E. aerogenes) was used as the biohydrogen producer via dark fermentation process using sago wastewater as the substrate. However, pretreatment of sago wastewater is required since it consists of complex sugars that cannot be utilized directly by the bacteria. This study aimed to use acid pretreatment method to produce high amount of glucose from sago wastewater. Three different types of acid: sulfuric acid (H2SO4); hydrochloric acid (HCl) and nitric acid (HNO3) were screened for the best acid in producing a maximum amount of glucose. H2SO4 gave the highest amount of glucose which was 9.406 g/L. Design of experiment was done using Face-centred Central Composite Design (FCCCD) tool under Response Surface Methodology (RSM) in Design Expert 9 software. The maximum glucose (9.138 g/L) was recorded using 1 M H2SO4 at 100 °C for 60 min. A batch dark fermentation using E. aerogenes was carried out and it was found that pretreated sago wastewater gave a higher hydrogen concentration (1700 ppm) compared to the raw wastewater (410 ppm).

The new species Enterobacter oryziphilus sp. nov. and Enterobacter oryzendophyticus sp. nov. are key inhabitants of the endosphere of rice

PubMed Central

2013-01-01

Background Six independent Gram-negative, facultatively anaerobic, non-spore-forming, nitrogen-fixing rod-shaped isolates were obtained from the root endosphere of rice grown at the International Rice Research Institute (IRRI) and investigated in a polyphasic taxonomic study. Results The strains produced fatty acid patterns typical for members of the family Enterobacteriaceae. Comparative sequence analyses of the 16S rRNA as well as rpoB genes allocated the strains to two well-defined groups within the genus Enterobacter, family Enterobacteriaceae. The analyses indicated Enterobacter radicincitans, Enterobacter arachidis and Enterobacter oryzae to be the closest related species. An RpoB (translated) protein comparison supported the placement in the genus Enterobacter and the relatedness of our isolates to the aforementioned species. Genomic DNA:DNA hybridization analyses and biochemical analyses provided further evidence that the novel strains belong to two new species within the genus Enterobacter. The two species can be differentiated from each other and from existing enteric species by acid production from L-rhamnose and D-melibiose, decarboxylation of ornithine and utilization of D-alanine, D-raffinose L-proline and L-aspartic acid, among other characteristics. Members of both species revealed capacities to colonise rice roots, including plant-growth-promoting capabilities such as an active supply of fixed nitrogen to the plant and solubilisation of inorganic phosphorus, next to traits allowing adaptation to the plant. Conclusions Two novel proposed enterobacterial species, denominated Enterobacter oryziphilus sp. nov. (type strain REICA_142T=LMG 26429T=NCCB 100393T) and Enterobacter oryzendophyticus sp. nov. (type strain REICA_082T=LMG 26432T =NCCB 100390T) were isolated from rice roots. Both species are capable of promoting rice growth by supplying nitrogen and phosphorus. PMID:23865888

Preflight and postflight microbiological results from 25 space shuttle crews

NASA Technical Reports Server (NTRS)

Pierson, Duane L.; Bassinger, Virginia J.; Molina, Thomas C.; Gunter, Emelie G.; Groves, Theron O.; Cioletti, Louis J.; Mishra, S. K.

1993-01-01

Clinical-microbiological investigations are an important aspect of the crew health stabilization program. To ensure that space crews have neither active nor latent infections, clinical specimens, including throat and nasal swabs and urine samples, are collected at 10 days (L-10) and 2days (L-2) before launch, and immediately after landing (L+0). All samples are examined for the presence of bacteria and fungi. In addition, fecal samples are collected at L-10 and examined for bacteria, fungi and parasites. This paper describes clinical-microbiological findings from 144 astronauts participating in 25 Space Shuttle missions spanning Space Transportation System (STS)-26 to STS-50. The spectrum of microbiological findings from the specimens included 25 bacterial and 11 fungal species. Among the bacteria isolated most frequently were Staphylococcus aureus, Enterobacter aerogenes, Enterococcus faecalis, Escherichia coli, Proteus mirabilis and Streptococcus agalactiae. Candida albicans was the most frequently isolated fungal pathogen.

Spondylodiscitis Caused by Enterobacter agglomerans

PubMed Central

Kothalawala, Mahen; Devakanthan, Balachandran; Arunan, Sinnappoo; Galgamuwa, Dinithi; Rathnayake, Manori

2016-01-01

All over the globe, the incidence of vertebral infection is rising. Nowadays, compared to tuberculous variety, pyogenic spondylodiscitis incidence is high. The increase in the susceptible population and improved diagnostics summatively contributed to this. In clinical grounds, differentiation of pyogenic and tuberculous spondylodiscitis is well defined. Enterobacter agglomerans is a hospital contaminant and associated with infections in immunocompromised individuals and intravenous lines. It causes a wide array of infections. Enterobacter agglomerans spondylodiscitis is unusual and there are, around the globe, only less than 31 suspected cases that have been previously reported. Enterobacter agglomerans histology mimics tuberculous rather than pyogenic spondylodiscitis. A 65-year-old farming lady, while being in hospital, developed sudden onset spastic paraparesis with hyperreflexia. Later blood culture revealed Enterobacter agglomerans with 41-hour incubation in 99.9% probability from Ramel identification system. Her initial ESR was 120 mm/first hour. Isolate was susceptible to ciprofloxacin and intravenous followed with oral therapy shows a drastic ESR fall and improved clinical response. Differentiation of tuberculous and pyogenic spondylodiscitis is very much important in management point of view. Therefore, blood culture has a role in diagnosis of spondylodiscitis. ESR can be used as important inflammatory marker in monitoring the response to treatment. Retrospectively, ESR would aid in reaching a definitive diagnosis. PMID:28127480

Carbene-aerogen bonds: an ab initio study

NASA Astrophysics Data System (ADS)

Esrafili, Mehdi D.; Sabouri, Ayda

2017-04-01

Through the use of ab initio calculations, the possibility of formation of σ-hole interaction between ZO3 (Z = Ar, Kr and Xe) and carbene species is investigated. Since singlet carbenes show a negative electrostatic potential on their divalent carbon atom, they can favourably interact with the positive electrostatic potential generated by the σ-hole of Z atom of ZO3. The characteristic of this interaction, termed as 'carbene-aerogen' bond, is analysed in terms of geometric, interaction energies and electronic features. The energy decomposition analysis indicates that for all complexes analysed here, the electrostatic energy is more negative than the polarisation or dispersion energy term. According to the electron density analysis, some partial covalent character can be ascribed to XeṡṡṡC interactions. In addition, the carbene-aerogen bond exhibits cooperative effects with the HṡṡṡO hydrogen-bonding interaction in ternary complexes where both interactions coexist. For a given carbene, the amount of these cooperative effects increases with the size of the Z atom. The results obtained in this work may be helpful for the extension and future application of σ-hole intermolecular interactions as well as coordination chemistry.

Genetic characterisation of tigecycline-resistant Enterobacter spp. in blood isolates causing bacteraemia.

PubMed

Cha, Min Kyeong; Kang, Cheol-In; Park, Ga Eun; Kim, So Hyun; Chung, Doo Ryeon; Peck, Kyong Ran; Song, Jae-Hoon

2018-01-05

Tigecycline (TIG) is one of the most important antimicrobial agents used to treat infections by multidrug-resistant bacteria. However, rates of TIG-resistant pathogens have increased recently. This study was conducted to identify the antimicrobial susceptibility profiles and to investigate the role of efflux pumps in high-level TIG-resistant Enterobacter spp. isolates causing bacteraemia. A total of 323 Enterobacter spp. causing bacteraemia were collected from eight hospitals in various regions of South Korea. Minimum inhibitory concentrations (MICs) were determined by the broth microdilution method and Etest. Expression levels of the efflux pump gene acrA and its regulators (ramA and rarA) were examined by quantitative real-time PCR. Isolate relatedness was determined by multilocus sequence typing (MLST). Among the 323 clinical isolates included in this study, 37 (11.5%) were TIG-non-susceptible, of which 8 isolates were highly resistant to TIG with MICs of 8mg/L (4 isolates) or 16mg/L (4 isolates). All high-level TIG-resistant isolates showed increased expression of acrA (0.93-13.3-fold) and ramA (1.4-8.2-fold). Isolates with a tigecycline MIC of 16mg/L also showed overexpression of rarA compared with TIG-susceptible isolates. In this study, overexpression of acrA, ramA and rarA was observed in high-level TIG-resistant Enterobacter spp. isolates. We suggest that rarA might be involved in the regulation of acrA overexpression in high-level TIG-resistant Enterobacter spp. isolates. Efflux pump-mediated resistance should be closely monitored because it could be indirectly attributed to the use of other antibiotics transported by the same efflux pump. Copyright © 2017. Published by Elsevier Ltd.

Microbial Colonization in a New Intensive Care Burn Unit. A Prospective Cohort Study

DTIC Science & Technology

1985-02-01

after transfer to the convalescent ward were added to the Total 0 1 ICU patients and presented as a total. Analysis of fre- Enterobacter aerogenes ...ProvIdencia stuartil 0 4 ICU 4 4 Enterobacter agglomerons 3 0 Total 7 9• "•"".’-,••Pseudomonas putida 0 3 t’•••P*ICU indicates Intensive care unit...Staphylococcus aureus Klebsiela pneumonias 1 2 ICU 14 19 Total 18 20 Enterobacter cloacae 0 2 nt.c ussce- Streptococcus pneurnonlae 0 2"".Enterococcus peciesi

Oxidation/Biodegradation of Solid Propellants Used in Legacy Chemical Rounds

DTIC Science & Technology

2007-08-01

Bioreactor Sample Source Sample Number Similarity Index Genus Species ICB M28-1 Sample 1A 0.771 Kluyvera cryocrescenes 0.704 Enterobacter cloacae...0.678 Photorhabdus luminencent 0.676 Entrobacter aerogenes Sample 1B 0.901 Alcaligenes faecalis Sample 2 0.894 Pseudomonas stutzeri 0.807 Pseudomonas...et. al. 13 has also described the role of Enterobacter cloacae NADH in the degradation of nitro aromatic compounds. Paracoccus denitrificans, commonly

Antibacterial activity of BMS-180680, a new catechol-containing monobactam.

PubMed Central

Fung-Tomc, J; Bush, K; Minassian, B; Kolek, B; Flamm, R; Gradelski, E; Bonner, D

1997-01-01

The in vitro activities of a new catechol-containing monobactam, BMS-180680 (SQ 84,100), were compared to those of aztreonam, ceftazidime, imipenem, piperacillin-tazobactam, ciprofloxacin, amikacin, and trimethoprim-sulfamethoxazole. BMS-180680 was often the most active compound against many species of the family Enterobacteriaceae, with MICs at which 90% of the isolates were inhibited (MIC90s) of < or = 0.5 microg/ml for Escherichia coli, Klebsiella spp., Citrobacter diversus, Enterobacter aerogenes, Serratia marcescens, Proteus spp., and Providencia spp. BMS-180680 had moderate activities (MIC90s of 2 to 8 microg/ml) against Citrobacter freundii, Morganella morganii, Shigella spp., and non-E. aerogenes Enterobacter spp. BMS-180680 was the only antibiotic evaluated that was active against >90% of the Pseudomonas aeruginosa (MIC90, 0.25 microg/ml), Burkholderia cepacia, and Stenotrophomonas maltophilia (MIC90s, 1 microg/ml) strains tested. BMS-180680 was inactive against most strains of Pseudomonas fluorescens, Pseudomonas stutzeri, Pseudomonas diminuta, and Burkholderia pickettii. BMS-180680 was moderately active (MIC90s of 4 to 8 microg/ml) against Alcaligenes spp. and Acinetobacter lwoffii and less active (MIC90, 16 microg/ml) against Acinetobacter calcoaceticus-Acinetobacter baumanii complex. BMS-180680 lacked activity against gram-positive bacteria and anaerobic bacteria. Both tonB and cir fiu double mutants of E. coli had greatly decreased susceptibility to BMS-180680. Of the TEM, PSE, and chromosomal-encoded beta-lactamases tested, only the K1 enzyme hydrolyzed BMS-180680 to any measurable extent. Like aztreonam, BMS-180680 bound preferentially to penicillin-binding protein 3. The MICs of BMS-180680 were not influenced by the presence of hematin or 5% sheep blood in the test medium or with incubation in an atmosphere containing 5% CO2. BMS-180680 MICs obtained under strict anaerobic conditions were significantly higher than those obtained in ambient air

Evidence supporting dissimilatory and assimilatory lignin degradation in Enterobacter lignolyticus SCF1

DOE Office of Scientific and Technical Information (OSTI.GOV)

DeAngelis, Kristen M.; Sharma, Deepak; Varney, Rebecca

2013-08-29

The anaerobic isolate Enterobacter lignolyticus SCF1 was initially cultivated based on anaerobic growth on lignin as sole carbon source. The source of the isolated bacteria was from tropical forest soils that decompose litter rapidly with low and fluctuating redox potentials, making it likely that bacteria using oxygen-independent enzymes play an important role in decomposition. We have examined differential expression of the anaerobic isolate Enterobacter lignolyticus SCF1 during growth on lignin. After 48 hours of growth, we used transcriptomics and proteomics to define the enzymes and other regulatory machinery that these organisms use to degrade lignin, as well as metabolomics tomore » measure lignin degradation and monitor the use of lignin and iron as terminal electron acceptors that facilitate more efficient use of carbon. Proteomics revealed accelerated xylose uptake and metabolism under lignin-amended growth, and lignin degradation via the 4-hydroxyphenylacetate degradation pathway, catalase/peroxidase enzymes, and the glutathione biosynthesis and glutathione S-transferase proteins. We also observed increased production of NADH-quinone oxidoreductase, other electron transport chain proteins, and ATP synthase and ATP-binding cassette (ABC) transporters. Our data shows the advantages of a multi-omics approach, where incomplete pathways identified by genomics were completed, and new observations made on coping with poor carbon availability. The fast growth, high efficiency and specificity of enzymes employed in bacterial anaerobic litter deconstruction makes these soils useful templates for improving biofuel production.« less

Coliform inhibition by bacteriocin-like substances in drinking water distribution systems.

PubMed Central

Means, E G; Olson, B H

1981-01-01

Bacterial isolates from an unchlorinated potable groundwater system and a chlorinated surface water system were screened by an agar overlay method for the ability to produce bacteriocin-like substances (BLS) inhibitory to the growth of Escherichia coli, Klebsiella sp., and Enterobacter aerogenes. The production of coliform-specific BLS by noncoliform bacteria varied with the site and date of isolation as well as the genus of the producer strain. A total of 448 bacterial isolates were screened from the chlorinated system, and 22.1% produced BLS specific for at least one of the three coliforms. In the unchlorinated system, 7.9% (n = 696) possessed this ability. Flavobacterium/Moraxella comprised 57.1% of all bacteria (from both systems) producing BLS. The possibility that BLS interfere with coliform detection in standard bacteriological water quality tests is discussed. Images PMID:7027953

Discovery and biological characterization of geranylated RNA in bacteria.

PubMed

Dumelin, Christoph E; Chen, Yiyun; Leconte, Aaron M; Chen, Y Grace; Liu, David R

2012-11-01

A general MS-based screen for unusually hydrophobic cellular small molecule-RNA conjugates revealed geranylated RNA in Escherichia coli, Enterobacter aerogenes, Pseudomonas aeruginosa and Salmonella enterica var. Typhimurium. The geranyl group is conjugated to the sulfur atom in two 5-methylaminomethyl-2-thiouridine nucleotides. These geranylated nucleotides occur in the first anticodon position of tRNA(Glu)(UUC), tRNA(Lys)(UUU) and tRNA(Gln)(UUG) at a frequency of up to 6.7% (~400 geranylated nucleotides per cell). RNA geranylation can be increased or abolished by mutation or deletion of the selU (ybbB) gene in E. coli, and purified SelU protein in the presence of geranyl pyrophosphate and tRNA can produce geranylated tRNA. The presence or absence of the geranyl group in tRNA(Glu)(UUC), tRNA(Lys)(UUU) and tRNA(Gln)(UUG) affects codon bias and frameshifting during translation. These RNAs represent the first reported examples of oligoisoprenylated cellular nucleic acids.

Reclassification of Enterobacter oryziphilus and Enterobacter oryzendophyticus as Kosakonia oryziphila comb. nov. and Kosakonia oryzendophytica comb. nov.

PubMed

Li, Chun Yan; Zhou, Yuan Liang; Ji, Jing; Gu, Chun Tao

2016-08-01

The taxonomic positions of Enterobacter oryziphilus and Enterobacter oryzendophyticus were re-examined on the basis of concatenated partial rpoB, atpD, gyrB and infB gene sequence analysis. The reconstructed phylogenetic tree based upon concatenated partial rpoB, atpD, gyrB and infB gene sequences clearly showed that E. oryziphilus and E. oryzendophyticus and all defined species of the genus Kosakonia form a clade separate from other genera of the family Enterobacteriaceae, and, therefore, these species of the genus Enterobacter should be transferred to the genus Kosakonia. E. oryziphilus and E. oryzendophyticus are reclassified as K. oryziphila comb. nov. (type strain REICA_142T=LMG 26429T=NCCB 100393T) and K. oryzendophytica comb. nov. (type strain REICA_082T=LMG 26432T=NCCB 100390T), respectively.

Non-thiolate ligation of nickel by nucleotide-free UreG of Klebsiella aerogenes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin-Diaconescu, Vlad; Joseph, Crisjoe A.; Boer, Jodi L.

Nickel-dependent ureases are activated by a multiprotein complex that includes the GTPase UreG. Prior studies showed that nucleotide-free UreG from Klebsiella aerogenes is monomeric and binds one nickel or zinc ion with near-equivalent affinity using an undefined binding site, whereas nucleotide-free UreG from Helicobacter pylori selectively binds one zinc ion per dimer via a universally conserved Cys-Pro-His motif in each protomer. Iodoacetamide-treated K. aerogenes UreG was nearly unaffected in nickel binding compared to non-treated sample, suggesting the absence of thiolate ligands to the metal. X-ray absorption spectroscopy of nickel-bound UreG showed the metal possessed four-coordinate geometry with all O/N donormore » ligands including one imidazole, thus confirming the absence of thiolate ligation. The nickel site in Strep-tag II-modified protein possessed six-coordinate geometry, again with all O/N donor ligands, but now including two or three imidazoles. An identical site was noted for the Strep-tag II-modified H74A variant, substituted in the Cys-Pro-His motif, ruling out coordination by this His residue. These results are consistent with metal binding to both His6 and a His residue of the fusion peptide in Strep-tagged K. aerogenes UreG. We conclude that the nickel- and zinc-binding site in nucleotide-free K. aerogenes UreG is distinct from that of nucleotide-free H. pylori UreG and does not involve the Cys-Pro-His motif. Further, we show the Strep-tag II can perturb metal coordination of this protein.« less

Colistin Heteroresistance in Enterobacter cloacae Is Associated with Cross-Resistance to the Host Antimicrobial Lysozyme

PubMed Central

Napier, Brooke A.; Band, Victor

2014-01-01

Here, we describe the first identification of colistin-heteroresistant Enterobacter cloacae in the United States. Treatment of this isolate with colistin increased the frequency of the resistant subpopulation and induced cross-resistance to the host antimicrobial lysozyme. This is the first description of heteroresistance conferring cross-resistance to a host antimicrobial and suggests that clinical treatment with colistin may inadvertently select for bacteria that are resistant to components of the host innate immune system. PMID:24982068

Enterobacter xiangfangensis sp. nov., isolated from Chinese traditional sourdough, and reclassification of Enterobacter sacchari Zhu et al. 2013 as Kosakonia sacchari comb. nov.

PubMed

Gu, Chun Tao; Li, Chun Yan; Yang, Li Jie; Huo, Gui Cheng

2014-08-01

A Gram-stain-negative bacterial strain, 10-17(T), was isolated from traditional sourdough in Heilongjiang Province, China. The bacterium was characterized by a polyphasic approach, including 16S rRNA gene sequence analysis, RNA polymerase β subunit (rpoB) gene sequence analysis, DNA gyrase (gyrB) gene sequence analysis, initiation translation factor 2 (infB) gene sequence analysis, ATP synthase β subunit (atpD) gene sequence analysis, fatty acid methyl ester analysis, determination of DNA G+C content, DNA-DNA hybridization and an analysis of phenotypic features. Strain 10-17(T) was phylogenetically related to Enterobacter hormaechei CIP 103441(T), Enterobacter cancerogenus LMG 2693(T), Enterobacter asburiae JCM 6051(T), Enterobacter mori LMG 25706(T), Enterobacter ludwigii EN-119(T) and Leclercia adecarboxylata LMG 2803(T), having 99.5%, 99.3%, 98.7%, 98.5%, 98.4% and 98.4% 16S rRNA gene sequence similarity, respectively. On the basis of polyphasic characterization data obtained in the present study, a novel species, Enterobacter xiangfangensis sp. nov., is proposed and the type strain is 10-17(T) ( = LMG 27195(T) = NCIMB 14836(T) = CCUG 62994(T)). Enterobacter sacchari Zhu et al. 2013 was reclassified as Kosakonia sacchari comb. nov. on the basis of 16S rRNA, rpoB, gyrB, infB and atpD gene sequence analysis and the type strain is strain SP1(T)( = CGMCC 1.12102(T) = LMG 26783(T)). © 2014 IUMS.

Genome Sequence of the Plant Growth Promoting Endophytic Bacterium Enterobacter sp. 638

PubMed Central

Taghavi, Safiyh; van der Lelie, Daniel; Hoffman, Adam; Zhang, Yian-Biao; Walla, Michael D.; Vangronsveld, Jaco; Newman, Lee; Monchy, Sébastien

2010-01-01

Enterobacter sp. 638 is an endophytic plant growth promoting gamma-proteobacterium that was isolated from the stem of poplar (Populus trichocarpa×deltoides cv. H11-11), a potentially important biofuel feed stock plant. The Enterobacter sp. 638 genome sequence reveals the presence of a 4,518,712 bp chromosome and a 157,749 bp plasmid (pENT638-1). Genome annotation and comparative genomics allowed the identification of an extended set of genes specific to the plant niche adaptation of this bacterium. This includes genes that code for putative proteins involved in survival in the rhizosphere (to cope with oxidative stress or uptake of nutrients released by plant roots), root adhesion (pili, adhesion, hemagglutinin, cellulose biosynthesis), colonization/establishment inside the plant (chemiotaxis, flagella, cellobiose phosphorylase), plant protection against fungal and bacterial infections (siderophore production and synthesis of the antimicrobial compounds 4-hydroxybenzoate and 2-phenylethanol), and improved poplar growth and development through the production of the phytohormones indole acetic acid, acetoin, and 2,3-butanediol. Metabolite analysis confirmed by quantitative RT–PCR showed that, the production of acetoin and 2,3-butanediol is induced by the presence of sucrose in the growth medium. Interestingly, both the genetic determinants required for sucrose metabolism and the synthesis of acetoin and 2,3-butanediol are clustered on a genomic island. These findings point to a close interaction between Enterobacter sp. 638 and its poplar host, where the availability of sucrose, a major plant sugar, affects the synthesis of plant growth promoting phytohormones by the endophytic bacterium. The availability of the genome sequence, combined with metabolome and transcriptome analysis, will provide a better understanding of the synergistic interactions between poplar and its growth promoting endophyte Enterobacter sp. 638. This information can be further exploited to

Enumeration of Enterobacter cloacae after chloramine exposure.

PubMed Central

Watters, S K; Pyle, B H; LeChevallier, M W; McFeters, G A

1989-01-01

Growth of Enterobacter cloacae on various media was compared after disinfection. This was done to examine the effects of monochloramine and chlorine on the enumeration of coliforms. The media used were TLY (nonselective; 5.5% tryptic soy broth, 0.3% yeast extract, 1.0% lactose, and 1.5% Bacto-Agar), m-T7 (selective; developed to recover injured coliforms), m-Endo (selective; contains sodium sulfite), TLYS (TLY with sodium sulfite), and m-T7S (m-T7 with sodium sulfite). Sodium sulfite in any medium improved the recovery of chloramine-treated E. cloacae. However, sodium sulfite in TLYS and m-T7S did not significantly improve the detection of chlorine-treated E. cloacae, and m-Endo was the least effective medium for recovering chlorinated bacteria. Differences in recovery of chlorine- and chloramine-treated E. cloacae are consistent with mechanistic differences between the disinfectants. PMID:2619309

Re-examination of the taxonomic status of Enterobacter helveticus, Enterobacter pulveris and Enterobacter turicensis as members of the genus Cronobacter and their reclassification in the genera Franconibacter gen. nov. and Siccibacter gen. nov. as Franconibacter helveticus comb. nov., Franconibacter pulveris comb. nov. and Siccibacter turicensis comb. nov., respectively.

PubMed

Stephan, Roger; Grim, Christopher J; Gopinath, Gopal R; Mammel, Mark K; Sathyamoorthy, Venugopal; Trach, Larisa H; Chase, Hannah R; Fanning, Séamus; Tall, Ben D

2014-10-01

Recently, a taxonomical re-evaluation of the genus Enterobacter, based on multi-locus sequence typing (MLST) analysis, has led to the proposal that the species Enterobacter pulveris, Enterobacter helveticus and Enterobacter turicensis should be reclassified as novel species of the genus Cronobacter. In the present work, new genome-scale analyses, including average nucleotide identity, genome-scale phylogeny and k-mer analysis, coupled with previously reported DNA-DNA hybridization values and biochemical characterization strongly indicate that these three species of the genus Enterobacter are not members of the genus Cronobacter, nor do they belong to the re-evaluated genus Enterobacter. Furthermore, data from this polyphasic study indicated that all three species constitute two new genera. We propose reclassifying Enterobacter pulveris and Enterobacter helveticus in the genus Franconibacter gen. nov. as Franconibacter pulveris comb. nov. (type strain 601/05(T) = LMG 24057(T) = DSM 19144(T)) and Franconibacter helveticus comb. nov. (type strain 513/05(T) = LMG 23732(T) = DSM 18396(T)), respectively, and Enterobacter turicensis in the genus Siccibacter gen. nov. as Siccibacter turicensis comb. nov. (type strain 508/05(T) = LMG 23730(T) = DSM 18397(T)).

Re-examination of the taxonomic status of Enterobacter helveticus, Enterobacter pulveris and Enterobacter turicensis as members of the genus Cronobacter and their reclassification in the genera Franconibacter gen. nov. and Siccibacter gen. nov. as Franconibacter helveticus comb. nov., Franconibacter pulveris comb. nov. and Siccibacter turicensis comb. nov., respectively

PubMed Central

Grim, Christopher J.; Gopinath, Gopal R.; Mammel, Mark K.; Sathyamoorthy, Venugopal; Trach, Larisa H.; Chase, Hannah R.; Fanning, Séamus; Tall, Ben D.

2014-01-01

Recently, a taxonomical re-evaluation of the genus Enterobacter, based on multi-locus sequence typing (MLST) analysis, has led to the proposal that the species Enterobacter pulveris, Enterobacter helveticus and Enterobacter turicensis should be reclassified as novel species of the genus Cronobacter. In the present work, new genome-scale analyses, including average nucleotide identity, genome-scale phylogeny and k-mer analysis, coupled with previously reported DNA–DNA hybridization values and biochemical characterization strongly indicate that these three species of the genus Enterobacter are not members of the genus Cronobacter, nor do they belong to the re-evaluated genus Enterobacter. Furthermore, data from this polyphasic study indicated that all three species constitute two new genera. We propose reclassifying Enterobacter pulveris and Enterobacter helveticus in the genus Franconibacter gen. nov. as Franconibacter pulveris comb. nov. (type strain 601/05T = LMG 24057T = DSM 19144T) and Franconibacter helveticus comb. nov. (type strain 513/05T = LMG 23732T = DSM 18396T), respectively, and Enterobacter turicensis in the genus Siccibacter gen. nov. as Siccibacter turicensis comb. nov. (type strain 508/05T = LMG 23730T = DSM 18397T). PMID:25028159

Biological properties of the Chilean native moss Sphagnum magellanicum.

PubMed

Montenegro, Gloria; Portaluppi, Mariana C; Salas, Francisco A; Díaz, María F

2009-01-01

An ethanol extract prepared from the gametophyte Chilean native moss Sphagnum magellanicum was dried out, weighed and dissolved in distilled water. This extract was then assayed for its antibacterial activity against the G(-) bacteria Azotobacter vinelandii, Erwinia carotovora subsp. carotovora, Enterobacter aerogenes, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, Vibrio cholerae, and the G(+) bacteria Staphylococcus aureus subsp. aureus, and Streptococcus type beta. The growth of the cultures of E. carotovora subsp. carotovora, and V. cholerae was inhibited at a concentration of 581 microg/ml of extract, while the cultures of E. coli, S. typhi and Streptococcus type beta were inhibited at a concentration of 1.16 microg/mL of extract. The concentration of phenolic compounds was 4.294 mg/mL; the presence of vanillic, chlorogenic, syringic, caffeic, gallic, 3-4 hydrozybenzoic, p-coumaric and salicylic acids was identified using RP- High Pressure Liquid Chromatography.

RELATIONSHIP BETWEEN CELL SURFACE PROPERTIES AND TRANSPORT OF BACTERIA THROUGH SOIL

EPA Science Inventory

A study was conducted to relate the properties of Enterobacter, Pseudomonas, Bacillus, Achromobacter, Flavobacterium, and Arthrobacter strains to their transport with water moving through soil. the bacteria differed markedly in their extent of transport; their hydrophobicity, as...

Enterobacter muelleri sp. nov., isolated from the rhizosphere of Zea mays.

PubMed

Kämpfer, Peter; McInroy, John A; Glaeser, Stefanie P

2015-11-01

A beige-pigmented, oxidase-negative bacterial strain (JM-458T), isolated from a rhizosphere sample, was studied using a polyphasic taxonomic approach. Cells of the isolate were rod-shaped and stained Gram-negative. A comparison of the 16S rRNA gene sequence of strain JM-458T with sequences of the type strains of closely related species of the genus Enterobacter showed that it shared highest sequence similarity with Enterobacter mori (98.7 %), Enterobacter hormaechei (98.3 %), Enterobacter cloacae subsp. dissolvens, Enterobacter ludwigii and Enterobacter asburiae (all 98.2 %). 16S rRNA gene sequence similarities to all other Enterobacter species were below 98 %. Multilocus sequence analysis based on concatenated partial rpoB, gyrB, infB and atpD gene sequences showed a clear distinction of strain JM-458T from its closest related type strains. The fatty acid profile of the strain consisted of C16 : 0, C17 : 0 cyclo, iso-C15 : 0 2-OH/C16 : 1ω7c and C18 : 1ω7c as major components. DNA-DNA hybridizations between strain JM-458T and the type strains of E. mori, E. hormaechei and E. ludwigii resulted in relatedness values of 29 % (reciprocal 25 %), 24 % (reciprocal 43 %) and 16 % (reciprocal 17 %), respectively. DNA-DNA hybridization results together with multilocus sequence analysis results and differential biochemical and chemotaxonomic properties showed that strain JM-458T represents a novel species of the genus Enterobacter, for which the name Enterobacter muelleri sp. nov. is proposed. The type strain is JM-458T ( = DSM 29346T = CIP 110826T = LMG 28480T = CCM 8546T).

Q-PCR Based Culture-Independent Enumeration and Detection of Enterobacter: An Emerging Environmental Human Pathogen in Riverine Systems and Potable Water

PubMed Central

Patel, Chandra B.; Shanker, Rishi; Gupta, Vijai K.; Upadhyay, Ram S.

2016-01-01

The availability of safe and pristine water is a global challenge when large numbers of natural and anthropogenic water resources are being depleted with faster rate. The remaining water resources are severely contaminated with various kinds of contaminants including microorganisms. Enterobacter is one of the fecal coliform bacteria of family Enterobacteriaceae. Enterobacter was earlier used as an indicator bacterium along with other fecal Coliforms namely Escherichia coli, Citrobacter, and Klebsiella, but it is now known to cause various diseases in human beings. In this study, we have collected 55 samples from potable water and riverine system and proved their presence using their conserved sequences of 16S rRNA and 23S rRNA genes with the help of SYBR green real-time PCR, which showed very high specificity for the detection of Enterobacter. The Enterobacter counts in potable water were found to 1290 ± 32.89 to 1460 ± 39.42 cfu/100 ml. The Enterobacter levels in surface water were 1.76 × 104 ± 492, 1.33 × 104 ± 334, 1.15 × 104 ± 308, 2.56 × 104 ± 802, 2.89 × 104 ± 962, 8.16 × 104 ± 3443 cfu/100 ml; the levels of Enterobacter contamination associated with hydrophytes were 4.80 × 104 ± 1804, 3.48 × 104 ± 856, 8.50 × 104 ± 2074, 8.09 × 104 ± 1724, 6.30 × 104 ± 1738, 3.68 × 104 ± 949 cfu/10 g and the Enterobacter counts in sediments of the river, were 2.36 × 104 ± 703, 1.98 × 104 ± 530, 9.92 × 104 ± 3839, 6.80 × 104 ± 2230, 8.76 × 104 ± 3066 and 2.34 × 104 ± 732 cfu/10 g at the sampling Site #1, Site #2, Site #3, Site #4, Site #5, and Site #6, respectively. The assay could be used for the regular monitoring of potable water and other water reservoirs to check waterborne outbreaks. PMID:26925044

Enterobacter nimipressuralis as a cause of pseudobacteremia

PubMed Central

2010-01-01

Background The clinical significance of the Enterobacter nimipressuralis as human pathogens remains unclear. Case presentations The microbiologic culture monitoring system of sterile body fluids revealed on an episode of Enterobacter cloacae and Enterobacter amnigenus in blood culture results on the same day; the antibiotic sensitivity and MIC were nearly the same for both species. First patient was a healthy woman with postmenopausal syndrome, while second patient with herpes zoster. Both patients had febrile sensations without signs of bacteremia. E. amnigenus was also cultured from the unused package of salined cotton in the container through epidemiologic investigation. The cultured Enterobacter species were all identified as E. nimipressuralis through hsp60 gene sequencing and infrequent-restriction-site PCR (IRS-PCR). Conclusion When an unusual microorganisms such as E. nimipressuralis is isolated from blood of a patient with no clinical signs of sepsis, a pseudobacteremia should be suspected. When the antibiogram and MIC test results of bacterial cultures from two or more patients are nearly the same, although the species involved may appear different, it may be necessary to prove that they are the same species through molecular methods. The microbiologic cultures monitoring system will probably help to detect pseudobacteremia and other pseudo infections through reliable and fast identification. PMID:21029473

Characterization of Exoelectrogenic Bacteria Enterobacter Strains Isolated from a Microbial Fuel Cell Exposed to Copper Shock Load

PubMed Central

Feng, Cuijie; Li, Jiangwei; Qin, Dan; Chen, Lixiang; Zhao, Feng; Chen, Shaohua; Hu, Hongbo; Yu, Chang-Ping

2014-01-01

Microorganisms capable of generating electricity in microbial fuel cells (MFCs) have gained increasing interest. Here fourteen exoelectrogenic bacterial strains were isolated from the anodic biofilm in an MFC before and after copper (Cu) shock load by Hungate roll-tube technique with solid ferric (III) oxide as an electron acceptor and acetate as an electron donor. Phylogenetic analysis of the 16S rRNA gene sequences revealed that they were all closely related to Enterobacter ludwigii DSM 16688T within the Enterobacteriaceae family, although these isolated bacteria showed slightly different morphology before and after Cu shock load. Two representative strains R2B1 (before Cu shock load) and B4B2 (after Cu shock load) were chosen for further analysis. B4B2 is resistant to 200 mg L−1 of Cu(II) while R2B1 is not, which indicated the potential selection of the Cu shock load. Raman analysis revealed that both R2B1 and B4B2 contained c-type cytochromes. Cyclic voltammetry measurements revealed that strain R2B1 had the capacity to transfer electrons to electrodes. The experimental results demonstrated that strain R2B1 was capable of utilizing a wide range of substrates, including Luria-Bertani (LB) broth, cellulose, acetate, citrate, glucose, sucrose, glycerol and lactose to generate electricity, with the highest current density of 440 mA·m−2 generated from LB-fed MFC. Further experiments indicated that the bacterial cell density had potential correlation with the current density. PMID:25412475

Inorganic phosphate accumulation and cadmium detoxification in Klebsiella aerogenes NCTC 418 growing in continuous culture

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aiking, H.; Stijnman, A.; van Garderen, C.

1984-02-01

Klebsiella aerogenes NCTC-418, growing in the presence of cadmium under glucose-, sulfate-, or phosphate-limited conditions in continuous culture, exhibits two different cadmium detoxifying mechanisms. In addition to sulfide formation, increased accumulation of P/sub i/ is demonstrated as a novel mechanism. Intracellular cadmium is always quantitatively counterbalanced by a concerted increase in both inorganic sulfide and P/sub i/ contents of the cells. This led to the conclusion that production of sulfide and accumulation of P/sub i/ are detoxification mechanisms present in K. aerogenes but that their relative importance is crucially dependent on the strain and the growth conditions employed.

Pneumonia due to Enterobacter cancerogenus infection.

PubMed

Demir, Tülin; Baran, Gamze; Buyukguclu, Tuncay; Sezgin, Fikriye Milletli; Kaymaz, Haci

2014-11-01

Enterobacter cancerogenus (formerly known as CDC Enteric Group 19; synonym with Enterobacter taylorae) has rarely been associated with human infections, and little is known regarding the epidemiology and clinical significance of this organism. We describe a community-acquired pneumonia case in a 44-year-old female due to E. cancerogenus. Identification and antimicrobial susceptibility of the microorganism was performed by the automatized VITEK 2 Compact system (bioMerieux, France). The clinical case suggests that E. cancerogenus is a potentially pathogenic microorganism in determined circumstances; underlying diseases such as bronchial asthma, empiric antibiotic treatment, wounds, diagnostic, or therapeutic instruments.

Metal Accumulation and Vanadium-Induced Multidrug Resistance by Environmental Isolates of Escherichia hermannii and Enterobacter cloacae

PubMed Central

Hernández, Alicia; Mellado, Rafael P.; Martínez, José L.

1998-01-01

Contaminated soils from an oil refinery were screened for the presence of microorganisms capable of accumulating either nickel, vanadium, or both metals. Three strains of bacteria that belonged to the family Enterobacteriaceae were selected. Two of them were Escherichia hermannii strains, and outer membrane profile (OMP) analysis showed that they were similar to a strain of clinical origin; the other one was an Enterobacter cloacae strain that differed from clinical isolates. The selected bacteria accumulated both nickel and vanadium. Growth in the presence of vanadium induced multidrug resistance phenotypes in E. hermannii and E. cloacae. Incubation with this metal changed the OMP profile of E. hermannii but did not produce variations in the expression of the major OMPs of E. cloacae. PMID:9797283

Tomato ethylene sensitivity determines interaction with plant growth-promoting bacteria.

PubMed

Ibort, Pablo; Molina, Sonia; Núñez, Rafael; Zamarreño, Ángel María; García-Mina, José María; Ruiz-Lozano, Juan Manuel; Orozco-Mosqueda, Maria Del Carmen; Glick, Bernard R; Aroca, Ricardo

2017-07-01

Plant growth-promoting bacteria (PGPB) are soil micro-organisms able to interact with plants and stimulate their growth, positively affecting plant physiology and development. Although ethylene plays a key role in plant growth, little is known about the involvement of ethylene sensitivity in bacterial inoculation effects on plant physiology. Thus, the present study was pursued to establish whether ethylene perception is critical for plant-bacteria interaction and growth induction by two different PGPB strains, and to assess the physiological effects of these strains in juvenile and mature tomato ( Solanum lycopersicum ) plants. An experiment was performed with the ethylene-insensitive tomato never ripe and its isogenic wild-type line in which these two strains were inoculated with either Bacillus megaterium or Enterobacter sp. C7. Plants were grown until juvenile and mature stages, when biomass, stomatal conductance, photosynthesis as well as nutritional, hormonal and metabolic statuses were analysed. Bacillus megaterium promoted growth only in mature wild type plants. However, Enterobacter C7 PGPB activity affected both wild-type and never ripe plants. Furthermore, PGPB inoculation affected physiological parameters and root metabolite levels in juvenile plants; meanwhile plant nutrition was highly dependent on ethylene sensitivity and was altered at the mature stage. Bacillus megaterium inoculation improved carbon assimilation in wild-type plants. However, insensitivity to ethylene compromised B. megaterium PGPB activity, affecting photosynthetic efficiency, plant nutrition and the root sugar content. Nevertheless, Enterobacter C7 inoculation modified the root amino acid content in addition to stomatal conductance and plant nutrition. Insensitivity to ethylene severely impaired B. megaterium interaction with tomato plants, resulting in physiological modifications and loss of PGPB activity. In contrast, Enterobacter C7 inoculation stimulated growth independently of

Differentiation of bacterial colonies and temporal growth patterns using hyperspectral imaging

NASA Astrophysics Data System (ADS)

Mehrübeoglu, Mehrube; Buck, Gregory W.; Livingston, Daniel W.

2014-09-01

Detection and identification of bacteria are important for health and safety. Hyperspectral imaging offers the potential to capture unique spectral patterns and spatial information from bacteria which can then be used to detect and differentiate bacterial species. Here, hyperspectral imaging has been used to characterize different bacterial colonies and investigate their growth over time. Six bacterial species (Pseudomonas fluorescens, Escherichia coli, Serratia marcescens, Salmonella enterica, Staphylococcus aureus, Enterobacter aerogenes) were grown on tryptic soy agar plates. Hyperspectral data were acquired immediately after, 24 hours after, and 96 hours after incubation. Spectral signatures from bacterial colonies demonstrated repeatable measurements for five out of six species. Spatial variations as well as changes in spectral signatures were observed across temporal measurements within and among species at multiple wavelengths due to strengthening or weakening reflectance signals from growing bacterial colonies based on their pigmentation. Between-class differences and within-class similarities were the most prominent in hyperspectral data collected 96 hours after incubation.

A food additive with prebiotic properties of an α-d-glucan from lactobacillus plantarum DM5.

PubMed

Das, Deeplina; Baruah, Rwivoo; Goyal, Arun

2014-08-01

An α-d-glucan produced by Lactobacillus plantarum DM5 was explored for in vitro prebiotic activities. Glucan-DM5 demonstrated 21.6% solubility, 316.9% water holding capacity, 86.2% flocculation activity, 71.4% emulsification activity and a degradation temperature (Td) of 292.2°C. Glucan-DM5 exhibited lowest digestibility of 0.54% by artificial gastric juice, 0.21% by intestinal fluid and 0.32% by α-amylase whereas the standard prebiotic inulin, showed 25.23%, 5.97% and 19.13%, hydrolysis, respectively. Prebiotic activity assay of glucan-DM5 displayed increased growth of probiotic bacteria such as Bifidobacterium infantis and Lactobacillus acidophilus, but did not support the growth of non-probiotic bacteria such as Escherichia coli and Enterobacter aerogenes. The overall findings indicated that glucan from L. plantarum DM5 can serve as a potential prebiotic additive for food products. Copyright © 2014 Elsevier B.V. All rights reserved.

Temporal Trends in Enterobacter Species Bloodstream Infection: A Population-Based Study, 1998-2007

PubMed Central

Al-Hasan, Majdi N.; Lahr, Brian D.; Eckel-Passow, Jeanette E.; Baddour, Larry M.

2010-01-01

Enterobacter species are the fourth most common cause of gram-negative bloodstream infection (BSI). We examined temporal changes and seasonal variation in the incidence rate of Enterobacter spp. BSI, estimated 28-day and 1-year mortality, and determined in vitro antimicrobial resistance rates of Enterobacter spp. bloodstream isolates in Olmsted County, Minnesota, from 1/1/1998 to 12/31/2007. Multivariable Poisson regression was used to examine temporal changes and seasonal variation in incidence rate and Kaplan-Meier method to estimate 28-day and 1-year mortality. The median age of patients with Enterobacter spp. BSI was 58 years and 53% were female. The overall age- and gender-adjusted incidence rate of Enterobacter spp. BSI was 3.3/100,000 person-years (95% confidence interval [CI]: 2.3-4.4). There was a linear trend of increasing incidence rate from 0.8 (95% CI: 0-1.9) to 6.2 (95% CI: 3.0-9.3) per 100,000 person-years between 1998 and 2007 (p=0.002). There was no significant difference in the incidence rate of Enterobacter spp. BSI during the warmest four months compared to the remainder of the year (incidence rate ratio 1.06 [95% CI: 0.47-2.01]). The overall 28-day and 1-year mortality rates of Enterobacter spp. BSI were 21% (95% CI: 8-34%) and 38% (95% CI: 22-53%), respectively. Up to 13% of Enterobacter spp. bloodstream isolates were resistant to third-generation cephalosporins. To our knowledge, this is the first population-based study to describe the epidemiology and outcome of Enterobacter spp. BSI. The increase in incidence rate of Enterobacter spp. BSI over the past decade, coupled with its associated antimicrobial resistance, dictate more investigation of this syndrome. PMID:20518795

Production of biogenic amines by lactic acid bacteria and enterobacteria isolated from fresh pork sausages packaged in different atmospheres and kept under refrigeration.

PubMed

Curiel, J A; Ruiz-Capillas, C; de Las Rivas, B; Carrascosa, A V; Jiménez-Colmenero, F; Muñoz, R

2011-07-01

The occurrence of in vitro amino acid activity in bacterial strains associated with fresh pork sausages packaged in different atmospheres and kept in refrigeration was studied. The presence of biogenic amines in decarboxylase broth was confirmed by ion-exchange chromatography and by the presence of the corresponding decarboxylase genes by PCR. From the 93 lactic acid bacteria and 100 enterobacteria strains analysed, the decarboxylase medium underestimates the number of biogenic amine-producer strains. 28% of the lactic acid bacteria produced tyramine and presented the tdc gene. All the tyramine-producer strains were molecularly identified as Carnobacterium divergens. Differences on the relative abundance of C. divergens were observed among the different packaging atmospheres assayed. After 28 days of storage, the presence of argon seems to inhibit C. divergens growth, while packing under vacuum seems to favour it. Among enterobacteria, putrescine was the amine more frequently produced (87%), followed by cadaverine (85%); agmatine and tyramine were only produced by 13 and 1%, respectively, of the strains analysed. Packing under vacuum or in an atmosphere containing nitrogen seems to inhibit the growth of enterobacteria which produce simultaneously putrescine, cadaverine, and agmatine. Contrarily, over-wrapping or packing in an atmosphere containing argon seems to favour the growth of agmatine producer-enterobacteria. The production of putrescine and cadaverine was associated with the presence of the corresponding amino acid decarboxylase genes. The biogenic amine-producer strains were included in a wide range of enterobacterial species, including Kluyvera intermedia, Enterobacter aerogenes, Yersinia kristensenii, Serratia grimesii, Serratia ficaria, Yersinia rodhei, Providencia vermicola and Obesumbacterium proteus. Copyright © 2011 Elsevier Ltd. All rights reserved.

Association of Enterobacter cloacae and other bacteria with onion bulb rot in the Columbia Basin of Washington and Oregon, USA

USDA-ARS?s Scientific Manuscript database

Approximately 1.6 million metric tons of onion bulbs are produced annually in the Pacific Northwest USA. Bulb decay can be a major problem and is caused by a variety of plant pathogens. Onion bulbs exhibiting symptoms of bacterial rot were sampled to determine the causal agents. Enterobacter cloacae...

Isolation of phosphate solubilizing bacteria and their potential for lead immobilization in soil.

PubMed

Park, Jin Hee; Bolan, Nanthi; Megharaj, Mallavarapu; Naidu, Ravi

2011-01-30

Lead (Pb), a highly toxic heavy metal forms stable compounds with phosphate (P). The potential of phosphate solubilizing bacteria (PSB) to immobilize Pb by enhancing solubilization of insoluble P compounds was tested in this research. Eighteen different PSB strains isolated from P amended and Pb contaminated soils were screened for their efficiency in P solubilization. The PSB isolated from P amended soils solubilized 217-479 mg/L of P while the PSB from Pb contaminated soil solubilized 31-293 mg/L of P. Stepwise multiple regression analysis and P solubility kinetics indicated that the major mechanism of P solubilization by PSB is the pH reduction through the release of organic acids. From the isolated bacteria, two PSB were chosen for Pb immobilization and these bacteria were identified as Pantoea sp. and Enterobacter sp., respectively. The PSB significantly increased P solubilization by 25.0% and 49.9% in the case of Pantoea sp., and 63.3% and 88.6% in the case of Enterobacter sp. for 200 and 800 mg/kg of rock phosphate (RP) addition, respectively, thereby enhancing the immobilization of Pb by 8.25-13.7% in the case of Pantoea sp. and 14.7-26.4% in the case of Enterobacter sp. The ability of PSB to solubilize P, promote plant growth, and immobilize Pb can be used for phytostabilization of Pb contaminated soils. Copyright © 2010 Elsevier B.V. All rights reserved.

Growth and heavy metal removal by Klebsiella aerogenes at different pH and temperature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Al-Shahwani, M.F.; Jazrawi, S.F.; Al-Rawi, E.H.

1984-01-01

A strain of Klebsiella aerogenes isolated from Rustamiyah Station for treatment of wastewater was examined for its ability to grow in a media supplemented with maximum tolerance concentrations of Pb/sup + +/, Zn/sup + +/, Ni/sup + +/, and Cd/sup + +/, separately, at different temperatures and initial pH. The results indicated that at 28/sup 0/C during the first 24 hr, Pb/sup + +/ and Ni/sup + +/ had no effect on the growth of the bacteria, while the presence of Zn/sup + +/ and Cd/sup + +/ decreased the cell count. The growth reached a maximum level after themore » second day and started to decrease gradually. The bacterial count at 37/sup 0/C was less than that at 28/sup 0/C. No bacterial multiplication occurred at 44/sup 0/C. There was little difference between heavy metal removal at 28 and 37/sup 0/C. At 44/sup 0/C, little removal took place. In general, slightly acidic or neutral medium was better for both bacterial growth and metal removal.« less

Production of hydrogen and volatile fatty acid by Enterobacter sp. T4384 using organic waste materials.

PubMed

Kim, Byung-Chun; Deshpande, Tushar R; Chun, Jongsik; Yi, Sung Chul; Kim, Hyunook; Um, Youngsoon; Sang, Byoung-In

2013-02-01

In a study of hydrogen-producing bacteria, strain T4384 was isolated from rice field samples in the Republic of Korea. The isolate was identified as Enterobacter sp. T4384 by phylogenetic analysis of 16S rRNA and rpoB gene sequences. Enterobacter sp. T4384 grew at a temperature range of 10-45 degrees C and at an initial pH range of 4.5-9.5. Strain T4384 produced hydrogen at 0-6% NaCl by using glucose, fructose, and mannose. In serum bottle cultures using a complete medium, Enterobacter sp. T4384 produced 1,098 ml/l H2, 4.0 g/l ethanol, and 1.0 g/l acetic acid. In a pH-regulated jar fermenter culture with the biogas removed, 2,202 ml/l H2, 6.2 g/l ethanol, and 1.0 g/l acetic acid were produced, and the lag-phase time was 4.8 h. Strain T4384 metabolized the hydrolysate of organic waste for the production of hydrogen and volatile fatty acid. The strain T4384 produced 947 ml/l H2, 3.2 g/l ethanol, and 0.2 g/l acetic acid from 6% (w/v) food waste hydrolysate; 738 ml/l H2, 4.2 g/l ethanol, and 0.8 g/l acetic acid from Miscanthus sinensis hydrolysate; and 805 ml/l H2, 5.0 g/l ethanol, and 0.7 g/l acetic acid from Sorghum bicolor hydrolysate.

Regulation of tyramine oxidase synthesis in Klebsiella aerogenes.

PubMed Central

Okamura, H; Murooka, Y; Harada, T

1976-01-01

Tyramine oxidase in Klebsiella aerogenes is highly specific for tyramine, dopamine, octopamine, and norepinephrine, and its synthesis is induced specifically by these compounds. The enzyme is present in a membrane-bound form. The Km value for tyramine is 9 X 10(-4) M. Tyramine oxidase synthesis was subjected to catabolite repression by glucose in the presence of ammonium salts. Addition of cyclic adenosine 3',5'-monophosphate (cAMP) overcame the catabolite repression. A mutant strain, K711, which can produce a high level of beta-galactosidase in the presence of glucose and ammonium chloride, can also synthesize tyramine oxidase and histidase in the presence of inducer in glucose ammonium medium. Catabolite repression of tyramine oxidase synthesis was relieved when the cells were grown under conditions of nitrogen limitation, whereas beta-galactosidase was strongly repressed under these conditions. A cAMP-requiring mutant, MK54, synthesized tyramine oxidase rapidly when tyramine was used as the sole source of nitrogen in the absence of cAMP. However, a glutamine synthetase-constitutive mutant, MK94, failed to synthesize tyramine oxidase in the presence of glucose and ammonium chloride, although it synthesized histidase rapidly under these conditions. These results suggest that catabolite repression of tyramine oxidase synthesis in K. aerogenes is regulated by the intracellular level of cAMP and an unknown cytoplasmic factor that acts independently of cAMP and is formed under conditions of nitrogen limitation. PMID:179974

Population Screening Using Sewage Reveals Pan-Resistant Bacteria in Hospital and Community Samples.

PubMed

Meir-Gruber, Lital; Manor, Yossi; Gefen-Halevi, Shiraz; Hindiyeh, Musa Y; Mileguir, Fernando; Azar, Roberto; Smollan, Gill; Belausov, Natasha; Rahav, Galia; Shamiss, Ari; Mendelson, Ella; Keller, Nathan

2016-01-01

The presence of pan-resistant bacteria worldwide possesses a threat to global health. It is difficult to evaluate the extent of carriage of resistant bacteria in the population. Sewage sampling is a possible way to monitor populations. We evaluated the presence of pan-resistant bacteria in Israeli sewage collected from all over Israel, by modifying the pour plate method for heterotrophic plate count technique using commercial selective agar plates. This method enables convenient and fast sewage sampling and detection. We found that sewage in Israel contains multiple pan-resistant bacteria including carbapenemase resistant Enterobacteriacae carrying blaKPC and blaNDM-1, MRSA and VRE. blaKPC carrying Klebsiella pneumonia and Enterobacter cloacae were the most common Enterobacteriacae drug resistant bacteria found in the sewage locations we sampled. Klebsiella pneumonia, Enterobacter spp., Escherichia coli and Citrobacter spp. were the 4 main CRE isolated from Israeli sewage and also from clinical samples in our clinical microbiology laboratory. Hospitals and Community sewage had similar percentage of positive samplings for blaKPC and blaNDM-1. VRE was found to be more abundant in sewage in Israel than MRSA but there were more locations positive for MRSA and VRE bacteria in Hospital sewage than in the Community. Therefore, our upgrade of the pour plate method for heterotrophic plate count technique using commercial selective agar plates can be a useful tool for routine screening and monitoring of the population for pan-resistant bacteria using sewage.

Population Screening Using Sewage Reveals Pan-Resistant Bacteria in Hospital and Community Samples

PubMed Central

Mileguir, Fernando; Azar, Roberto; Smollan, Gill; Belausov, Natasha; Rahav, Galia; Shamiss, Ari; Mendelson, Ella; Keller, Nathan

2016-01-01

The presence of pan-resistant bacteria worldwide possesses a threat to global health. It is difficult to evaluate the extent of carriage of resistant bacteria in the population. Sewage sampling is a possible way to monitor populations. We evaluated the presence of pan-resistant bacteria in Israeli sewage collected from all over Israel, by modifying the pour plate method for heterotrophic plate count technique using commercial selective agar plates. This method enables convenient and fast sewage sampling and detection. We found that sewage in Israel contains multiple pan-resistant bacteria including carbapenemase resistant Enterobacteriacae carrying blaKPC and blaNDM-1, MRSA and VRE. blaKPC carrying Klebsiella pneumonia and Enterobacter cloacae were the most common Enterobacteriacae drug resistant bacteria found in the sewage locations we sampled. Klebsiella pneumonia, Enterobacter spp., Escherichia coli and Citrobacter spp. were the 4 main CRE isolated from Israeli sewage and also from clinical samples in our clinical microbiology laboratory. Hospitals and Community sewage had similar percentage of positive samplings for blaKPC and blaNDM-1. VRE was found to be more abundant in sewage in Israel than MRSA but there were more locations positive for MRSA and VRE bacteria in Hospital sewage than in the Community. Therefore, our upgrade of the pour plate method for heterotrophic plate count technique using commercial selective agar plates can be a useful tool for routine screening and monitoring of the population for pan-resistant bacteria using sewage. PMID:27780222

Inactivation of Enterobacter sakazakii, Bacillus cereus, and Salmonella typhimurium in powdered weaning food by electron-beam irradiation

NASA Astrophysics Data System (ADS)

Hong, Yun-Hee; Park, Ji-Yong; Park, Jong-Hyun; Chung, Myong-Soo; Kwon, Ki-Sung; Chung, Kyungsook; Won, Misun; Song, Kyung-Bin

2008-09-01

Inactivation of Enterobacter sakazakii, Bacillus cereus, and Salmonella typhimurium were evaluated in powdered weaning food using electron-beam irradiation. E. sakazakii, B. cereus, and S. typhimurium were eliminated by irradiation at 16, 8, and 8 kGy, respectively. The D10-vlaues of E. sakazakii, B. cereus, and S. typhimurium inoculated on powdered weaning food were 4.83, 1.22, and 0.98 kGy, respectively. The results suggest that electron-beam irradiation should inhibit the growth of pathogenic bacteria on baby food without impairing qualities.

Two Pathways of Glutamate Fermentation by Anaerobic Bacteria

PubMed Central

Buckel, Wolfgang; Barker, H. A.

1974-01-01

Two pathways are involved in the fermentation of glutamate to acetate, butyrate, carbon dioxide, and ammonia—the methylaspartate and the hydroxyglutarate pathways which are used by Clostridium tetanomorphum and Peptococcus aerogenes, respectively. Although these pathways give rise to the same products, they are easily distinguished by different labeling patterns of the butyrate when [4-14C]glutamate is used as substrate. Schmidt degradation of the radioactive butyrate from C. tetanomorphum yielded equally labeled propionate and carbon dioxide, whereas nearly all the radioactivity of the butyrate from P. aerogenes was recovered in the corresponding propionate. This procedure was used as a test for the pathway of glutamate fermentation by 15 strains (9 species) of anaerobic bacteria. The labeling patterns of the butyrate indicate that glutamate is fermented via the methylaspartate pathway by C. tetani, C. cochlearium, and C. saccarobutyricum, and via the hydroxyglutarate pathway by Acidaminococcus fermentans, C. microsporum, Fusobacterium nucleatum, and F. fusiformis. Enzymes specific for each pathway were assayed in crude extracts of the above organisms. 3-Methylaspartase was found only in clostridia which use the methylaspartate pathway, including Clostridium SB4 and C. sticklandii, which probably degrade glutamate to acetate and carbon dioxide by using a second amino acid as hydrogen acceptor. High levels of 2-hydroxyglutarate dehydrogenase were found exclusively in organisms that use the hydroxyglutarate pathway. The data indicate that only two pathways are involved in the fermentation of glutamate by the bacteria analyzed. The methylaspartate pathway appears to be used only by species of Clostridium, whereas the hydroxyglutarate pathway is used by representatives of several genera. PMID:4813895

Biochemical basis of mercury remediation and bioaccumulation by Enterobacter sp. EMB21.

PubMed

Sinha, Arvind; Kumar, Sumit; Khare, Sunil Kumar

2013-01-01

The aims of this study were to isolate metal bioaccumulating bacterial strains and to study their applications in removal of environmental problematic heavy metals like mercury. Five bacterial strains belonging to genera Enterobacter, Bacillus, and Pseudomonas were isolated from oil-spilled soil. Among these, one of the strains Enterobacter sp. EMB21 showed mercury bioaccumulation inside the cells simultaneous to its bioremediation. The bioaccumulation of remediated mercury was confirmed by transmission electron microscopy and energy dispersive X-ray. The mercury-resistant loci in the Enterobacter sp. EMB21 cells were plasmid-mediated as confirmed by transformation of mercury-sensitive Escherichia coli DH5α by Enterobacter sp. EMB21 plasmid. Effect of different culture parameters viz-a-viz inoculum size, pH, carbon, and nitrogen source revealed that alkaline pH and presence of dextrose and yeast extract favored better remediation. The results indicated the usefulness of Enterobacter sp. EMB21 for the effective remediation of mercury in bioaccumulated form. The Enterobacter sp. EMB21 seems promising for heavy metal remediation wherein the remediated metal can be trapped inside the cells. The process can further be developed for the synthesis of valuable high-end functional alloy, nanoparticles, or metal conjugates from the metal being remediated.

Distribution, genetic diversity and antibiotic resistance of clinically important bacteria from the environment of a tertiary hospital.

PubMed

Phoon, Hannah Y P; Hussin, Hazilawati; Hussain, Baizurah Mohd; Lim, Shu Yong; Woon, Jia Jie; Er, Yi Xian; Thong, Kwai Lin

2018-03-11

Hospital environments are potential reservoirs of bacteria associated with nosocomial infections. Here, we determined the distribution of cultivable environmental bacteria of clinical importance from a Malaysian tertiary hospital and to investigate their resistotypes and genotypes. Swab and fluid samples (n=358) from healthcare workers' hands, frequently touched surfaces, medical equipment, patients' immediate surroundings, ward sinks and toilets and solutions or fluids of 12 selected wards were collected. Biochemical tests, PCR and 16S rRNA sequencing were used for identification after isolation from CHROMagar TM Orientation medium. Clinically important bacteria such as Enterococcus spp., Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter spp., Pseudomonas aeruginosa, and Enterobacter spp. were further characterised by disk diffusion method and REP-PCR. The 32 Gram negative and 21 Gram positive bacteria species identified were widely distributed in the hospital environment. Staphylococci were predominant followed by Bacillus spp., and P. aeruginosa. Frequently touched surfaces, medical equipment and ward sinks and toilets were the top three sources of bacterial species. Nine S. aureus, four Acinetobacter spp., one K. pneumoniae, and one Enterobacter spp., were multidrug resistant (MDR). The ESKAPE organisms were genetically diverse and widely dispersed across the hospital wards. An MDR MRSA clone was detected in a surgical ward isolation room. The large variety of cultivable, clinically important bacteria, especially the genetically related MDR S. aureus, K. pneumoniae, Acinetobacter spp., and Enterobacter spp. from various sampling sites indicated that the surfaces and fomites in the hospital were potential exogenous sources of nosocomial infections in the hospital. Copyright © 2018 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved.

A multiple antibiotic-resistant enterobacter cloacae strain isolated from a bioethanol fermentation facility.

PubMed

Murphree, Colin A; Li, Qing; Heist, E Patrick; Moe, Luke A

2014-09-17

An Enterobacter cloacae strain (E. cloacae F3S3) that was collected as part of a project to assess antibiotic resistance among bacteria isolated from bioethanol fermentation facilities demonstrated high levels of resistance to antibiotics added prophylactically to bioethanol fermentors. PCR assays revealed the presence of canonical genes encoding resistance to penicillin (ampC) and erythromycin (ermG). Assays measuring biofilm formation under antibiotic stress indicated that erythromycin induced biofilm formation in E. cloacae F3S3. Planktonic growth and biofilm formation were observed at a high ethanol content, indicating E. cloacae F3S3 can persist in a bioethanol fermentor under the highly variable environmental conditions found in fermentors.

Effect of Several Clay Minerals and Humic Acid on the Survival of Klebsiella aerogenes Exposed to Ultraviolet Irradiation1

PubMed Central

Bitton, Gabriel; Henis, Y.; Lahav, N.

1972-01-01

The effect of various clay minerals and humic acid on the survival of Klebsiella aerogenes exposed to ultraviolet (UV) irradiation was investigated. A protective effect was observed and found to depend on the specific light absorption and light scattering properties of the clay minerals and the humic acid used. The higher the specific absorption, the better was the survival of K. aerogenes after UV irradiation. Bacterial survival was lower in clays saturated with divalent cations (Ca, Zn) than in those homoionic to monovalent cations (K). PMID:5031559

Treatment outcomes in patients with third-generation cephalosporin-resistant Enterobacter bacteremia.

PubMed

O'Neal, Catherine S; O'Neal, Hollis R; Daniels, Titus L; Talbot, Thomas R

2012-10-01

Infections with resistant Enterobacter spp. are increasingly described, yet data on outcomes associated with these infections are limited. A retrospective cohort study was conducted to investigate outcomes of hospitalized patients with third-generation cephalosporin-resistant (CR) Enterobacter bacteremia. Cephalosporin resistance was detected using cefotaxime and cefpodoxime. Patients with Enterobacter spp. bacteremia from January 2006 through February 2008 defined the population. We defined cases as those with CR isolates; controls were patients with bacteremia due to non-CR isolates. Treatment failure was defined as persistence of the presenting signs of infection 72 h after initial culture collection. Of the 95 Enterobacter cases identified, 31 (33%) were CR. CR cases were significantly associated with treatment failure (odds ratio (OR) 2.81, 95% confidence interval (CI) 1.14-6.94). This association was not seen after adjustment for age, simplified acute physiology score (SAPS II), and inappropriate empiric antibiotic therapy. Inappropriate empiric therapy (adjusted OR 3.86, 95% CI 1.32-11.31) and SAPS II score (adjusted OR 1.09, 95% CI 1.02-1.16) were significantly associated with treatment failure in the multivariate analysis. Third-generation cephalosporin-resistant Enterobacter bacteremia is associated with treatment failure due to receipt of inappropriate empiric antibiotic therapy and severity of illness.

Efficacy of imipenem/cilastatin in endocarditis.

PubMed

Dickinson, G; Rodriguez, K; Arcey, S; Alea, A; Greenman, R

1985-06-07

Imipenem, a potent new beta-lactam antibiotic, which is bactericidal against most pathogenic bacteria, and cilastatin, a dehydropeptidase inhibitor combined with imipenem to prevent the metabolism of imipenem in the kidney, were evaluated in the treatment of bacterial endocarditis. Seventeen patients, including 14 who used intravenous drugs, were treated with imipenem/cilastatin in a dose of 500 mg each infused over 30 minutes every six hours. The mean duration of treatment was 29 days with a range of 21 to 56 days. Causative bacteria were Staphylococcus aureus in 10 patients, S. aureus plus group B Streptococcus in one, viridans group Streptococcus in two, Neisseria subflava, Eikenella corrodens, and group G Streptococcus in one patient, and Staphylococcus epidermidis, Hemophilus aphrophilus, and Enterobacter aerogenes in one patient each. The minimal bactericidal concentration of imipenem against 16 of 18 isolates tested was 0.04 micrograms/ml, 1 microgram/ml against H. aphrophilus, and 0.4 micrograms/ml against E. aerogenes. The site of infection was the right side of the heart in 11 patients, the left side in five, and both sides in one. The mean number of days to defervescence was 9.7. All patients were cured, and none required cardiac surgery. Adverse effects were few and interrupted treatment occurred in only one patient who had acute dyspnea during an infusion on Day 26 of therapy. Imipenem/cilastatin appears to be a relatively safe and highly effective treatment of staphylococcal endocarditis in intravenous drug users; too few patients with endocarditis caused by other bacteria were treated to allow a firm statement about efficacy in non-staphylococcal endocarditis.

Enterobacter tabaci sp. nov., a novel member of the genus Enterobacter isolated from a tobacco stem.

PubMed

Duan, Yan-Qing; Zhou, Xing-Kui; Di-Yan, Li; Li, Qing-Qing; Dang, Li-Zhi; Zhang, Yong-Guang; Qiu, Li-Hong; Nimaichand, Salam; Li, Wen-Jun

2015-11-01

A Gram-stain negative, motile, rod-shaped bacterium, designated strain YIM Hb-3(T), was isolated from the stem of a tobacco plant. The strain was observed to form convex, circular and yellow-colored colonies. The predominant respiratory quinone was identified as Q-8. The major fatty acids (>5%) detected were C(16:1)ω7c and/or C(16:1)ω6c (summed feature 3), C(16:0), C(17:0)cyclo, C(18:1)ω7c and/or C(18:1)ω6c (summed feature 8), C(14:0)3-OH and/or iso-C(16:1)I (summed feature 2), C(14:0) and C(12:0). The genomic DNA G+C content was determined to be 54.8 mol%. Phylogenetic trees based on 16S rRNA gene sequences and multilocus sequence analysis showed that strain YIM Hb-3(T) had the closest phylogenetic relationship with Enterobacter mori LMG 25706(T). DNA-DNA relatedness value between strain YIM Hb-3(T) and E. mori LMG 25706(T) was 46.9 ± 3.8%. On the basis of phenotypic and chemotaxonomic data, phylogenetic analysis, and DNA-DNA relatedness value, strain YIM Hb-3(T) is considered to represent a novel species of the genus Enterobacter, for which the name Enterobacter tabaci sp. nov. is proposed. The type strain is YIM Hb-3(T) (=KACC 17832(T) =KCTC 42694(T)).

Extreme furfural tolerance of a soil bacterium Enterobacter cloacae GGT036.

PubMed

Choi, Sun Young; Gong, Gyeongtaek; Park, Hong-Sil; Um, Youngsoon; Sim, Sang Jun; Woo, Han Min

2015-01-10

Detoxification process of cellular inhibitors including furfural is essential for production of bio-based chemicals from lignocellulosic biomass. Here we isolated an extreme furfural-tolerant bacterium Enterobacter cloacae GGT036 from soil sample collected in Mt. Gwanak, Republic of Korea. Among isolated bacteria, only E. cloacae GGT036 showed cell growth with 35 mM furfural under aerobic culture. Compared to the maximal half inhibitory concentration (IC50) of well-known industrial strains Escherichia coli (24.9 mM furfural) and Corynebacterium glutamicum (10 mM furfural) based on the cell density, IC50 of E. cloacae GGT036 (47.7 mM) was significantly higher after 24 h, compared to E. coli and C. glutamicum. Since bacterial cell growth was exponentially inhibited depending on linearly increased furfural concentrations in the medium, we concluded that E. cloacae GGT036 is an extreme furfural-tolerant bacterium. Recently, the complete genome sequence of E. cloacae GGT036 was announced and this could provide an insight for engineering of E. cloacae GGT036 itself or other industrially relevant bacteria. Copyright © 2014 Elsevier B.V. All rights reserved.

Complete genome sequence of “Enterobacter lignolyticus” SCF1

DOE Office of Scientific and Technical Information (OSTI.GOV)

DeAngelis, Kristen M.; D'Haeseleer, Patrik; Chivian, Dylan

2011-09-23

In an effort to discover anaerobic bacteria capable of lignin degradation, we isolated 'Ente-robacter lignolyticus' SCF1 on minimal media with alkali lignin as the sole source of carbon. This organism was isolated anaerobically from tropical forest soils collected from the Short Cloud Forest site in the El Yunque National Forest in Puerto Rico, USA, part of the Luquillo Long-Term Ecological Research Station. At this site, the soils experience strong fluctuations in redox potential and are net methane producers. Because of its ability to grow on lignin anae-robically, we sequenced the genome. The genome of 'E. lignolyticus' SCF1 is 4.81 Mbpmore » with no detected plasmids, and includes a relatively small arsenal of lignocellulolytic carbohy-drate active enzymes. Lignin degradation was observed in culture, and the genome revealed two putative laccases, a putative peroxidase, and a complete 4-hydroxyphenylacetate degra-dation pathway encoded in a single gene cluster.« less

Comparative Genome Analysis of Enterobacter cloacae

PubMed Central

Liu, Wing-Yee; Wong, Chi-Fat; Chung, Karl Ming-Kar; Jiang, Jing-Wei; Leung, Frederick Chi-Ching

2013-01-01

The Enterobacter cloacae species includes an extremely diverse group of bacteria that are associated with plants, soil and humans. Publication of the complete genome sequence of the plant growth-promoting endophytic E. cloacae subsp. cloacae ENHKU01 provided an opportunity to perform the first comparative genome analysis between strains of this dynamic species. Examination of the pan-genome of E. cloacae showed that the conserved core genome retains the general physiological and survival genes of the species, while genomic factors in plasmids and variable regions determine the virulence of the human pathogenic E. cloacae strain; additionally, the diversity of fimbriae contributes to variation in colonization and host determination of different E. cloacae strains. Comparative genome analysis further illustrated that E. cloacae strains possess multiple mechanisms for antagonistic action against other microorganisms, which involve the production of siderophores and various antimicrobial compounds, such as bacteriocins, chitinases and antibiotic resistance proteins. The presence of Type VI secretion systems is expected to provide further fitness advantages for E. cloacae in microbial competition, thus allowing it to survive in different environments. Competition assays were performed to support our observations in genomic analysis, where E. cloacae subsp. cloacae ENHKU01 demonstrated antagonistic activities against a wide range of plant pathogenic fungal and bacterial species. PMID:24069314

Improvement of plant growth and seed yield in Jatropha curcas by a novel nitrogen-fixing root associated Enterobacter species

PubMed Central

2013-01-01

Background Jatropha curcas L. is an oil seed producing non-leguminous tropical shrub that has good potential to be a fuel plant that can be cultivated on marginal land. Due to the low nutrient content of the targeted plantation area, the requirement for fertilizer is expected to be higher than other plants. This factor severely affects the commercial viability of J. curcas. Results We explored the feasibility to use endophytic nitrogen-fixing bacteria that are native to J. curcas to improve plant growth, biomass and seed productivity. We demonstrated that a novel N-fixing endophyte, Enterobacter sp. R4-368, was able to colonize in root and stem tissues and significantly promoted early plant growth and seed productivity of J. curcas in sterilized and non-sterilized soil. Inoculation of young seedling led to an approximately 57.2% increase in seedling vigour over a six week period. At 90 days after planting, inoculated plants showed an average increase of 25.3%, 77.7%, 27.5%, 45.8% in plant height, leaf number, chlorophyll content and stem volume, respectively. Notably, inoculation of the strain led to a 49.0% increase in the average seed number per plant and 20% increase in the average single seed weight when plants were maintained for 1.5 years in non-sterilized soil in pots in the open air. Enterobacter sp. R4-368 cells were able to colonize root tissues and moved systemically to stem tissues. However, no bacteria were found in leaves. Promotion of plant growth and leaf nitrogen content by the strain was partially lost in nifH, nifD, nifK knockout mutants, suggesting the presence of other growth promoting factors that are associated with this bacterium strain. Conclusion Our results showed that Enterobacter sp. R4-368 significantly promoted growth and seed yield of J. curcas. The application of the strains is likely to significantly improve the commercial viability of J. curcas due to the reduced fertilizer cost and improved oil yield. PMID:24083555

Enrichment and characterization of hydrocarbon-degrading bacteria from petroleum refinery waste as potent bioaugmentation agent for in situ bioremediation.

PubMed

Sarkar, Poulomi; Roy, Ajoy; Pal, Siddhartha; Mohapatra, Balaram; Kazy, Sufia K; Maiti, Mrinal K; Sar, Pinaki

2017-10-01

Intrinsic biodegradation potential of bacteria from petroleum refinery waste was investigated through isolation of cultivable strains and their characterization. Pseudomonas and Bacillus spp. populated the normal cultivable taxa while prolonged enrichment with hydrocarbons and crude oil yielded hydrocarbonoclastic bacteria of genera Burkholderia, Enterobacter, Kocuria, Pandoraea, etc. Strains isolated through enrichment showed assemblages of superior metabolic properties: utilization of aliphatic (C6-C22) and polyaromatic compounds, anaerobic growth with multiple terminal electron acceptors and higher biosurfactant production. Biodegradation of dodecane was studied thoroughly by GC-MS along with detection of gene encoding alkane hydroxylase (alkB). Microcosms bioaugmented with Enterobacter, Pandoraea and Burkholderia strains showed efficient biodegradation (98% TPH removal) well fitted in first order kinetic model with low rate constants and decreased half-life. This study proves that catabolically efficient bacteria resides naturally in complex petroleum refinery wastes and those can be useful for bioaugmentation based bioremediation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Microbiological Features of KPC-Producing Enterobacter Isolates Identified in a U.S. Hospital System

PubMed Central

Ahn, Chulsoo; Syed, Alveena; Hu, Fupin; O’Hara, Jessica A.; Rivera, Jesabel I.; Doi, Yohei

2014-01-01

Microbiological data regarding KPC-producing Enterobacter spp. are scarce. In this study, 11 unique KPC-producing Enterobacter isolates were identified among 44 ertapenem-non-susceptible Enterobacter isolates collected between 2009 and 2013 at a hospital system in Western Pennsylvania. All cases were healthcare-associated and occurred in medically complex patients. While pulsed-field gel electrophoresis (PFGE) showed diverse restriction patterns overall, multilocus sequence typing (MLST) identified Enterobacter cloacae isolates with sequence types (STs) 93 and 171 from two hospitals each. The levels of carbapenem minimum inhibitory concentrations were highly variable. All isolates remained susceptible to colistin, tigecycline, and the majority to amikacin and doxycycline. A blaKPC-carrying IncN plasmid conferring trimethoprim-sulfamethoxazole resistance was identified in three of the isolates. Spread of blaKPC in Enterobacter spp. appears to be due to a combination of plasmid-mediated and clonal processes. PMID:25053203

Exploring the dynamics of fluorescence staining of bacteria with cyanine dyes for the development of kinetic assays

NASA Astrophysics Data System (ADS)

Thomas, Marlon Sheldon

Bacterial infections continue to be one of the major health risks in the United States. The common occurrence of such infection is one of the major contributors to the high cost of health care and significant patient mortality. The work presented in this thesis describes spectroscopic studies that will contribute to the development of a fluorescent assay that may allow the rapid identification of bacterial species. Herein, the optical interactions between six bacterial species and a series of thiacyanine dyes are investigated. The interactions between the dyes and the bacterial species are hypothesized to be species-specific. For this thesis, two Gram-negative strains, Escherichia coli (E. coli) TOP10 and Enterobacter aerogenes; two Gram-positive bacterial strains, Bacillus sphaericus and Bacillus subtilis; and two Bacillus endospores, B. globigii and B. thuringiensis, were used to test the proposed hypothesis. A series of three thiacyanine dyes---3,3'-diethylthiacyanine iodide (THIA), 3,3'-diethylthiacarbocyanine iodide (THC) and thiazole orange (THO)---were used as fluorescent probes. The basis of our spectroscopic study was to explore the bacterium-induced interactions of the bacterial cells with the individual thiacyanine dyes or with a mixture of the three dyes. Steady-state absorption spectroscopy revealed that the different bacterial species altered the absorption properties of the dyes. Mixed-dye solutions gave unique absorption patterns for each bacteria tested, with competitive binding observed between the bacteria and spectrophotometric probes (thiacyanine dyes). Emission spectroscopy recorded changes in the emission spectra of THIA following the introduction of bacterial cells. Experimental results revealed that the emission enhancement of the dyes resulted from increases in the emission quantum yield of the thiacyanine dyes upon binding to the bacteria cellular components. The recorded emission enhancement data were fitted to an exponential (mono

A halotolerant Enterobacter sp. displaying ACC deaminase activity promotes rice seedling growth under salt stress.

PubMed

Sarkar, Anumita; Ghosh, Pallab Kumar; Pramanik, Krishnendu; Mitra, Soumik; Soren, Tithi; Pandey, Sanjeev; Mondal, Monohar Hossain; Maiti, Tushar Kanti

2018-01-01

Agricultural productivity is proven to be hampered by the synthesis of reactive oxygen species (ROS) and production of stress-induced ethylene under salinity stress. One-aminocyclopropane-1-carboxylic acid (ACC) is the direct precursor of ethylene synthesized by plants. Bacteria possessing ACC deaminase activity can use ACC as a nitrogen source preventing ethylene production. Several salt-tolerant bacterial strains displaying ACC deaminase activity were isolated from rice fields, and their plant growth-promoting (PGP) properties were determined. Among them, strain P23, identified as an Enterobacter sp. based on phenotypic characteristics, matrix-assisted laser desorption ionization-time of flight mass spectrometry data and the 16S rDNA sequence, was selected as the best-performing isolate for several PGP traits, including phosphate solubilization, IAA production, siderophore production, HCN production, etc. Enterobacter sp. P23 was shown to promote rice seedling growth under salt stress, and this effect was correlated with a decrease in antioxidant enzymes and stress-induced ethylene. Isolation of an acdS mutant strain enabled concluding that the reduction in stress-induced ethylene content after inoculation of strain P23 was linked to ACC deaminase activity. Copyright © 2017 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Isolation, identification, characterization, and evaluation of cadmium removal capacity of Enterobacter species.

PubMed

Abbas, Syed Zaghum; Rafatullah, Mohd; Ismail, Norli; Lalung, Japareng

2014-12-01

This study focused on the isolation and characterization of high cadmium-resistant bacterial strains, possible exploitation of its cadmium-accumulation and cadmium-induced proteins. Cadmium-resistant bacterial strains designated as RZ1 and RZ2 were isolated from industrial wastewater of Penang, Malaysia. These isolates were identified as Enterobacter mori and Enterobacter sp. WS12 on the basis of phenotypic, biochemical and 16S rDNA sequence based molecular phylogenetic characteristics. Both isolates were Gram negative, cocci, and growing well in Lauria-Bertani broth medium at 35 °C temperature and pH 7.0. Results also indicated that Enterobacter mori and Enterobacter sp. WS12are capable to remove 87.75 and 85.11% of the cadmium from 100 µg ml(-1) concentration, respectively. This study indicates that these strains can be useful as an inexpensive and efficient bioremediation technology to remove and recover the cadmium from wastewater. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Antibiotic failure mediated by a resistant subpopulation in Enterobacter cloacae

PubMed Central

Band, Victor I.; Crispell, Emily K.; Napier, Brooke A.; Herrera, Carmen M.; Tharp, Greg K.; Vavikolanu, Kranthi; Pohl, Jan; Read, Timothy D.; Bosinger, Steven E.; Trent, M. Stephen; Burd, Eileen M.; Weiss, David S.

2016-01-01

Antibiotic resistance is a major public health threat, further complicated by unexplained treatment failures caused by bacteria that appear antibiotic susceptible. We describe an Enterobacter cloacae isolate harbouring a minor subpopulation that is highly resistant to the last-line antibiotic colistin. This subpopulation was distinct from persisters, became predominant in colistin, returned to baseline after colistin removal and was dependent on the histidine kinase PhoQ. During murine infection, but in the absence of colistin, innate immune defences led to an increased frequency of the resistant subpopulation, leading to inefficacy of subsequent colistin therapy. An isolate with a lower-frequency colistin-resistant subpopulation similarly caused treatment failure but was misclassified as susceptible by current diagnostics once cultured outside the host. These data demonstrate the ability of low-frequency bacterial subpopulations to contribute to clinically relevant antibiotic resistance, elucidating an enigmatic cause of antibiotic treatment failure and highlighting the critical need for more sensitive diagnostics. PMID:27572838

Rapid identification of ESKAPE bacterial strains using an autonomous microfluidic device.

PubMed

Ho, Jack Y; Cira, Nate J; Crooks, John A; Baeza, Josue; Weibel, Douglas B

2012-01-01

This article describes Bacteria ID Chips ('BacChips'): an inexpensive, portable, and autonomous microfluidic platform for identifying pathogenic strains of bacteria. BacChips consist of a set of microchambers and channels molded in the elastomeric polymer, poly(dimethylsiloxane) (PDMS). Each microchamber is preloaded with mono-, di-, or trisaccharides and dried. Pressing the layer of PDMS into contact with a glass coverslip forms the device; the footprint of the device in this article is ∼6 cm(2). After assembly, BacChips are degased under large negative pressure and are stored in vacuum-sealed plastic bags. To use the device, the bag is opened, a sample containing bacteria is introduced at the inlet of the device, and the degased PDMS draws the sample into the central channel and chambers. After the liquid at the inlet is consumed, air is drawn into the BacChip via the inlet and provides a physical barrier that separates the liquid samples in adjacent microchambers. A pH indicator is admixed with the samples prior to their loading, enabling the metabolism of the dissolved saccharides in the microchambers to be visualized. Importantly, BacChips operate without external equipment or instruments. By visually detecting the growth of bacteria using ambient light after ∼4 h, we demonstrate that BacChips with ten microchambers containing different saccharides can reproducibly detect the ESKAPE panel of pathogens, including strains of: Enterococcus faecalis, Enteroccocus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter aerogenes, and Enterobacter cloacae. This article describes a BacChip for point-of-care detection of ESKAPE pathogens and a starting point for designing multiplexed assays that identify bacterial strains from clinical samples and simultaneously determine their susceptibility to antibiotics.

Rapid Identification of ESKAPE Bacterial Strains Using an Autonomous Microfluidic Device

PubMed Central

Ho, Jack Y.; Cira, Nate J.; Crooks, John A.; Baeza, Josue; Weibel, Douglas B.

2012-01-01

This article describes Bacteria ID Chips (‘BacChips’): an inexpensive, portable, and autonomous microfluidic platform for identifying pathogenic strains of bacteria. BacChips consist of a set of microchambers and channels molded in the elastomeric polymer, poly(dimethylsiloxane) (PDMS). Each microchamber is preloaded with mono-, di-, or trisaccharides and dried. Pressing the layer of PDMS into contact with a glass coverslip forms the device; the footprint of the device in this article is ∼6 cm2. After assembly, BacChips are degased under large negative pressure and are stored in vacuum-sealed plastic bags. To use the device, the bag is opened, a sample containing bacteria is introduced at the inlet of the device, and the degased PDMS draws the sample into the central channel and chambers. After the liquid at the inlet is consumed, air is drawn into the BacChip via the inlet and provides a physical barrier that separates the liquid samples in adjacent microchambers. A pH indicator is admixed with the samples prior to their loading, enabling the metabolism of the dissolved saccharides in the microchambers to be visualized. Importantly, BacChips operate without external equipment or instruments. By visually detecting the growth of bacteria using ambient light after ∼4 h, we demonstrate that BacChips with ten microchambers containing different saccharides can reproducibly detect the ESKAPE panel of pathogens, including strains of: Enterococcus faecalis, Enteroccocus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter aerogenes, and Enterobacter cloacae. This article describes a BacChip for point-of-care detection of ESKAPE pathogens and a starting point for designing multiplexed assays that identify bacterial strains from clinical samples and simultaneously determine their susceptibility to antibiotics. PMID:22848451

Geraniol Restores Antibiotic Activities against Multidrug-Resistant Isolates from Gram-Negative Species▿ †

PubMed Central

Lorenzi, Vannina; Muselli, Alain; Bernardini, Antoine François; Berti, Liliane; Pagès, Jean-Marie; Amaral, Leonard; Bolla, Jean-Michel

2009-01-01

The essential oil of Helichrysum italicum significantly reduces the multidrug resistance of Enterobacter aerogenes, Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii. Combinations of the two most active fractions of the essential oil with each other or with phenylalanine arginine β-naphthylamide yield synergistic activity. Geraniol, a component of one fraction, significantly increased the efficacy of β-lactams, quinolones, and chloramphenicol. PMID:19258278

Enterobacter siamensis sp. nov., a transglutaminase-producing bacterium isolated from seafood processing wastewater in Thailand.

PubMed

Khunthongpan, Suwannee; Bourneow, Chaiwut; H-Kittikun, Aran; Tanasupawat, Somboon; Benjakul, Soottawat; Sumpavapol, Punnanee

2013-01-01

A novel strain of Enterobacter, C2361(T), a Gram-negative, non-spore-forming, rod-shaped and facultative anaerobic bacterium with the capability to produce transglutaminase, was isolated from seafood processing wastewater collected from a treatment pond of a seafood factory in Songkhla Province, Thailand. Phylogenetic analyses and phenotypic characteristics, including chemotaxonomic characteristics, showed that the strain was a member of the genus Enterobacter. The 16S rRNA gene sequence similarities between strain C2361(T) and Enterobacter cloacae subsp. cloacae ATCC 13047(T) and Enterobacter cloacae subsp. dissolvens LMG 2683(T) were 97.5 and 97.5%, respectively. Strain C2361(T) showed a low DNA-DNA relatedness with the above-mentioned species. The major fatty acids were C16:0, C17:0cyclo and C14:0. The DNA G+C content was 53.0 mol%. On the basis of the polyphasic evidence gathered in this study, it should be classified as a novel species of the genus Enterobacter for which the name Enterobacter siamensis sp. nov. is proposed. The type strain is C2361(T) (= KCTC 23282(T) = NBRC 107138(T)).

Numerical taxonomy and ecology of petroleum-degrading bacteria

DOE Office of Scientific and Technical Information (OSTI.GOV)

Austin, B.; Calomiris, J.J.; Walker, J.D.

1977-07-01

A total of 99 strains of petroleum-degrading bacteria isolated from Chesapeake Bay water and sediment were identified by using numerical taxonomy procedures. The isolates, together with 33 reference cultures, were examined for 48 biochemical, cultural, morphological, and physiological characters. The data were analyzed by computer, using both the simple matching and the Jaccard coefficients. Clustering was achieved by the unweighted average linkage method. From the sorted similarity matrix and dendrogram, 14 phenetic groups, comprising 85 of the petroleum-degrading bacteria, were defined at the 80 to 85% similarity level. These groups were identified as actinomycetes (mycelial forms, four clusters), coryneforms, Enterobacteriaceae,more » Klebsiella aerogenes, Micrococcus spp. (two clusters), Nocardia species (two clusters), Pseudomonas spp. (two clusters), and Sphaerotilus natans. It is concluded that the degradation of petroleum is accomplished by a diverse range of bacterial taxa, some of which were isolated only at given sampling stations and, more specifically, from sediment collected at a given station.« less

Numerical taxonomy and ecology of petroleum-degrading bacteria.

PubMed Central

Austin, B; Calomiris, J J; Walker, J D; Colwell, R R

1977-01-01

A total of 99 strains of petroleum-degrading bacteria isolated from Chesapeake Bay water and sediment were identified by using numerical taxonomy procedures. The isolates, together with 33 reference cultures, were examined for 48 biochemical, cultural, morphological, and physiological characters. The data were analyzed by computer, using both the simple matching and the Jaccard coefficients. Clustering was achieved by the unweighted average linkage method. From the sorted similarity matrix and dendrogram, 14 phenetic groups, comprising 85 of the petroleum-degrading bacteria, were defined at the 80 to 85% similarity level. These groups were identified as actinomycetes (mycelial forms, four clusters), coryneforms, Enterobacteriaceae, Klebsiella aerogenes, Micrococcus spp. (two clusters), Nocardia species (two clusters), Pseudomonas spp. (two clusters), and Sphaerotilus natans. It is concluded that the degradation of petroleum is accomplished by a diverse range of bacterial taxa, some of which were isolated only at given sampling stations and, more specifically, from sediment collected at a given station. PMID:889329

Comparative study of thermostability and ester synthesis ability of free and immobilized lipases on cross linked silica gel.

PubMed

Kumari, Annapurna; Mahapatra, Paramita; Kumar, Garlapati Vijay; Banerjee, Rintu

2008-06-01

A novel support has been utilized for immobilization of lipase, which was prepared by amination of silica with ethanolamine followed by cross linking with glutaraldehyde. Lipases from Rhizopus oryzae 3562 and Enterobacter aerogenes were immobilized on activated silica gel, where they retained 60 and 50% of respective original activity. The thermal stability of the immobilized lipases was significantly improved in comparison to the free forms while the pH stability remained unchanged. E. aerogenes and R. oryzae 3562 lipases retained 75 and 97% of respective initial activity on incubation at 90 degrees C, whereas both the free forms became inactive at this temperature. The conversion yield of isoamyl acetate was found to be higher with the immobilized fungal (90 vs. 21%) and bacterial lipases (64 vs. 18%) than the respective free forms. Immobilized R. oryzae 3562 lipases retained 50% activity for isoamyl acetate synthesis up to ten cycles whereas it was eight cycles for E. aerogenes.

Enumeration and Identification of Coliform Bacteria Injured by Chlorine or Fungicide Mixed with Agricultural Water.

PubMed

Izumi, Hidemi; Nakata, Yuji; Inoue, Ayano

2016-10-01

Chemical sanitizers may induce no injury (bacteria survive), sublethal injury (bacteria are injured), or lethal injury (bacteria die). The proportion of coliform bacteria that were injured sublethally by chlorine and fungicide mixed with agricultural water (pond water), which was used to dilute the pesticide solution, was evaluated using the thin agar layer (TAL) method. In pure cultures of Enterobacter cloacae , Escherichia coli , and E. coli O157:H7 (representing a human pathogen), the percentage of chlorine-injured cells was 69 to 77% for dilute electrolyzed water containing an available chlorine level of 2 ppm. When agricultural water was mixed with electrolyzed water, the percentage of injured coliforms in agricultural water was 75%. The isolation and identification of bacteria on TAL and selective media suggested that the chlorine stress caused injury to Enterobacter kobei . Of the four fungicide products tested, diluted to their recommended concentrations, Topsin-M, Sumilex, and Oxirane caused injury to coliform bacteria in pure cultures and in agricultural water following their mixture with each pesticide, whereas Streptomycin did not induce any injury to the bacteria. The percentage of injury was 45 to 97% for Topsin-M, 80 to 87% for Sumilex, and 50 to 97% for Oxirane. A comparison of the coliforms isolated from the pesticide solutions and then grown on either TAL or selective media indicated the possibility of fungicide-injured Rahnella aquatilis , Yersinia mollaretii , and E. coli . These results suggest the importance of selecting a suitable sanitizer and the necessity of adjusting the sanitizer concentration to a level that will kill the coliforms rather than cause sanitizer-induced cell injury that can result in the recovery of the coliforms.

Biosynthesis, characterization and antimicrobial activity of copper oxide nanoparticles (CONPs) produced using brown alga extract ( Bifurcaria bifurcata)

NASA Astrophysics Data System (ADS)

Abboud, Y.; Saffaj, T.; Chagraoui, A.; El Bouari, A.; Brouzi, K.; Tanane, O.; Ihssane, B.

2014-06-01

Recently, biosynthesis of nanoparticles has attracted scientists' attention because of the necessity to develop new clean, cost-effective and efficient synthesis techniques. In particular, metal oxide nanoparticles are receiving increasing attention in a large variety of applications. However, up to now, the reports on the biopreparation and characterization of nanocrystalline copper oxide are relatively few compared to some other metal oxides. In this paper, we report for the first time the use of brown alga ( Bifurcaria bifurcata) in the biosynthesis of copper oxide nanoparticles of dimensions 5-45 nm. The synthesized nanomaterial is characterized by UV-visible absorption spectroscopy and Fourier transform infrared spectrum analysis. X-ray diffraction confirms the formation and the crystalline nature of copper oxide nanomaterial. Further, these nanoparticles were found to exhibit high antibacterial activity against two different strains of bacteria Enterobacter aerogenes (Gram negative) and Staphylococcus aureus (Gram positive).

Bacterial cellulose synthesis mechanism of facultative anaerobe Enterobacter sp. FY-07.

PubMed

Ji, Kaihua; Wang, Wei; Zeng, Bing; Chen, Sibin; Zhao, Qianqian; Chen, Yueqing; Li, Guoqiang; Ma, Ting

2016-02-25

Enterobacter sp. FY-07 can produce bacterial cellulose (BC) under aerobic and anaerobic conditions. Three potential BC synthesis gene clusters (bcsI, bcsII and bcsIII) of Enterobacter sp. FY-07 have been predicted using genome sequencing and comparative genome analysis, in which bcsIII was confirmed as the main contributor to BC synthesis by gene knockout and functional reconstitution methods. Protein homology, gene arrangement and gene constitution analysis indicated that bcsIII had high identity to the bcsI operon of Enterobacter sp. 638; however, its arrangement and composition were same as those of BC synthesizing operon of G. xylinum ATCC53582 except for the flanking sequences. According to the BC biosynthesizing process, oxygen is not directly involved in the reactions of BC synthesis, however, energy is required to activate intermediate metabolites and synthesize the activator, c-di-GMP. Comparative transcriptome and metabolite quantitative analysis demonstrated that under anaerobic conditions genes involved in the TCA cycle were downregulated, however, genes in the nitrate reduction and gluconeogenesis pathways were upregulated, especially, genes in three pyruvate metabolism pathways. These results suggested that Enterobacter sp. FY-07 could produce energy efficiently under anaerobic conditions to meet the requirement of BC biosynthesis.

Bacterial cellulose synthesis mechanism of facultative anaerobe Enterobacter sp. FY-07

PubMed Central

Ji, Kaihua; Wang, Wei; Zeng, Bing; Chen, Sibin; Zhao, Qianqian; Chen, Yueqing; Li, Guoqiang; Ma, Ting

2016-01-01

Enterobacter sp. FY-07 can produce bacterial cellulose (BC) under aerobic and anaerobic conditions. Three potential BC synthesis gene clusters (bcsI, bcsII and bcsIII) of Enterobacter sp. FY-07 have been predicted using genome sequencing and comparative genome analysis, in which bcsIII was confirmed as the main contributor to BC synthesis by gene knockout and functional reconstitution methods. Protein homology, gene arrangement and gene constitution analysis indicated that bcsIII had high identity to the bcsI operon of Enterobacter sp. 638; however, its arrangement and composition were same as those of BC synthesizing operon of G. xylinum ATCC53582 except for the flanking sequences. According to the BC biosynthesizing process, oxygen is not directly involved in the reactions of BC synthesis, however, energy is required to activate intermediate metabolites and synthesize the activator, c-di-GMP. Comparative transcriptome and metabolite quantitative analysis demonstrated that under anaerobic conditions genes involved in the TCA cycle were downregulated, however, genes in the nitrate reduction and gluconeogenesis pathways were upregulated, especially, genes in three pyruvate metabolism pathways. These results suggested that Enterobacter sp. FY-07 could produce energy efficiently under anaerobic conditions to meet the requirement of BC biosynthesis. PMID:26911736

Characterization of Fe (III)-reducing enrichment culture and isolation of Fe (III)-reducing bacterium Enterobacter sp. L6 from marine sediment.

PubMed

Liu, Hongyan; Wang, Hongyu

2016-07-01

To enrich the Fe (III)-reducing bacteria, sludge from marine sediment was inoculated into the medium using Fe (OH)3 as the sole electron acceptor. Efficiency of Fe (III) reduction and composition of Fe (III)-reducing enrichment culture were analyzed. The results indicated that the Fe (III)-reducing enrichment culture with the dominant bacteria relating to Clostridium and Enterobacter sp. had high Fe (III) reduction of (2.73 ± 0.13) mmol/L-Fe (II). A new Fe (III)-reducing bacterium was isolated from the Fe (III)-reducing enrichment culture and identified as Enterobacter sp. L6 by 16S rRNA gene sequence analysis. The Fe (III)-reducing ability of strain L6 under different culture conditions was investigated. The results indicated that strain L6 had high Fe (III)-reducing activity using glucose and pyruvate as carbon sources. Strain L6 could reduce Fe (III) at the range of NaCl concentrations tested and had the highest Fe (III) reduction of (4.63 ± 0.27) mmol/L Fe (II) at the NaCl concentration of 4 g/L. This strain L6 could reduce Fe (III) with unique properties in adaptability to salt variation, which indicated that it can be used as a model organism to study Fe (III)-reducing activity isolated from marine environment. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Outbreak of a novel Enterobacter sp. carrying blaCTX-M-15 in a neonatal unit of a tertiary care hospital in Tanzania.

PubMed

Mshana, Stephen E; Gerwing, Lisa; Minde, Mercy; Hain, Torsten; Domann, Eugen; Lyamuya, Eligius; Chakraborty, Trinad; Imirzalioglu, Can

2011-09-01

Enterobacter hormaechei and Cronobacter sakazakii are amongst the most important causes of outbreaks of neonatal sepsis associated with powdered milk. In this study, we report for the first time an outbreak of a novel Enterobacter sp. harbouring bla(CTX-M-15) in a neonatal unit in Tanzania. Seventeen Gram-negative enteric isolates from neonatal blood cultures were studied. Antibiotic susceptibility was assessed by disc diffusion testing, and the presence of the bla(CTX-M-15) gene was established by polymerase chain reaction (PCR) and sequencing. Isolates were typed by pulsed-field gel electrophoresis (PFGE). Identification by biochemical profiling was followed by nucleotide sequencing of 16S ribosomal DNA (rDNA), rpoB and hsp60 alleles. Environmental sampling was done and control measures were established. Isolates were initially misidentified based on their fermentation characteristics and agglutination as Salmonella enterica serotype Paratyphi. All isolates were resistant to multiple antibiotics, except for ciprofloxacin and carbapenems, and were found to harbour bla(CTX-M-15) on a 291-kb narrow-range plasmid. PFGE analysis indicated the clonal outbreak of a single strain, infecting 17 neonates with a case fatality rate of 35%. The same strain was isolated from a milk bucket. Phylogenetic analysis using 16S rDNA, rpoB and hsp60 sequences permitted no definitive identification, clustering the strains in the Enterobacter cloacae complex with similarities of 92-98.8%. The data describe an outbreak of a novel bla(CTX-M-15)-positive, multiresistant Enterobacter strain in an African neonatal unit that can easily be misidentified taxonomically. These data highlight the need for constant surveillance of bacteria harbouring extended-spectrum β-lactamases as well as improvements in hygiene measures in developing countries. Copyright © 2011 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

Long Chain N-acyl Homoserine Lactone Production by Enterobacter sp. Isolated from Human Tongue Surfaces

PubMed Central

Yin, Wai-Fong; Purmal, Kathiravan; Chin, Shenyang; Chan, Xin-Yue; Chan, Kok-Gan

2012-01-01

We report the isolation of N-acyl homoserine lactone-producing Enterobacter sp. isolate T1-1 from the posterior dorsal surfaces of the tongue of a healthy individual. Spent supernatants extract from Enterobacter sp. isolate T1-1 activated the biosensor Agrobacterium tumefaciens NTL4(pZLR4), suggesting production of long chain AHLs by these isolates. High resolution mass spectrometry analysis of these extracts confirmed that Enterobacter sp. isolate T1-1 produced a long chain N-acyl homoserine lactone, namely N-dodecanoyl-homoserine lactone (C12-HSL). To the best of our knowledge, this is the first isolation of Enterobacter sp., strain T1-1 from the posterior dorsal surface of the human tongue and N-acyl homoserine lactones production by this bacterium. PMID:23202161

Polyhexamethylene guanidine hydrochloride shows bactericidal advantages over chlorhexidine digluconate against ESKAPE bacteria.

PubMed

Zhou, Zhongxin; Wei, Dafu; Lu, Yanhua

2015-01-01

More information regarding the bactericidal properties of polyhexamethylene guanidine hydrochloride (PHMG) against clinically important antibiotic-resistant ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogens needs to be provided for its uses in infection control. The bactericidal properties of PHMG and chlorhexidine digluconate (CHG) were compared based on their minimum inhibitory concentrations (MICs), minimum bactericidal concentrations, and time-course-killing curves against clinically important antibiotic-susceptible and antibiotic-resistant ESKAPE pathogens. Results showed that PHMG exhibited significantly higher bactericidal activities against methicillin-resistant Staphylococcus aureus, carbapenem-resistant Klebsiella pneumoniae, and ceftazidime-resistant Enterobacter spp. than CHG. A slight bactericidal advantage over CHG was obtained against vancomycin-resistant Enterococcus faecium, ciprofloxacin- and levofloxacin-resistant Acinetobacter spp., and multidrug-resistant Pseudomonas aeruginosa. In previous reports, PHMG had higher antimicrobial activity against almost all tested Gram-negative bacteria and several Gram-positive bacteria than CHG using MIC test. These studies support the further development of covalently bound PHMG in sterile-surface materials and the incorporation of PHMG in novel disinfectant formulas. © 2014 International Union of Biochemistry and Molecular Biology, Inc.

Kinetic model for microbial growth and desulphurisation with Enterobacter sp.

PubMed

Liu, Long; Guo, Zhiguo; Lu, Jianjiang; Xu, Xiaolin

2015-02-01

Biodesulphurisation was investigated by using Enterobacter sp. D4, which can selectively desulphurise and convert dibenzothiophene into 2-hydroxybiphenyl (2-HBP). The experimental values of growth, substrate consumption and product generation were obtained at 95 % confidence level of the fitted values using three models: Hinshelwood equation, Luedeking-Piret and Luedeking-Piret-like equations. The average error values between experimental values and fitted values were less than 10 %. These kinetic models describe all the experimental data with good statistical parameters. The production of 2-HBP in Enterobacter sp. was by "coupled growth".

Eight-Year Surveillance of Antimicrobial Resistance among Enterobacter Cloacae Isolated in the First Bethune Hospital

NASA Astrophysics Data System (ADS)

Zhou, Qi; Zhang, Man; Wang, Ailin; Xu, Jiancheng; Yuan, Ye

This study was to investigate the antimicrobial resistance of Enterobacter cloacae isolated in 8 consecutive years in the First Bethune Hospital. Disk diffusion test was used to study the antimicrobial resistance. The data were analyzed by WHONET 5 software according to Clinical and Laboratory Standards Institute (CLSI). Most of 683 strains of Enterobacter cloacae were collected from sputum 410 (60.0%), secretions and pus 105 (15.4%), urine 69 (10.1%) during the past 8 years. No Enterobacter cloacae was resistant to imipenem and meropenem in the First Bethune Hospital. The antimicrobial resistance of Enterobacter cloacae had increased in recent 8 years. The change of the antimicrobial resistance should be investigated in order to direct rational drug usage in the clinic and prevent bacterial strain of drug resistance from b eing transmitted.

Identification and Antibacterial Activity of Bacteria Isolated from Marine Sponge Haliclona (Reniera) sp. against Multi-Drug Resistant Human Pathogen

NASA Astrophysics Data System (ADS)

Ardhanu Asagabaldan, Meezan; Ayuningrum, D.; Kristiana, R.; Sabdono, A.; Radjasa, O. K.; Trianto, A.

2017-02-01

The marine sponge Haliclona (Reniera) sp. was a potential source of natural bioactive compounds. This sponge widely distributed along the coast of Panjang Island, Jepara, Indonesia. The aims of this research were to isolate the associated bacteria with Haliclona (Reniera) sp. and to screen the antibacterial activity against Multi-Drug Resistant (MDR) bacteria. Amount five bacteria were isolated using media selective for bacteria. The antibacterial activities of bacteria were performed by overlay methods. The bacteria strain PSP. 39-04 had the best activity against Pseudomonas aeruginosa, Staphylococcus aureus, Acinetobacter baumannii, and Enterobacter cloaceae. Based on colony morphology and phylogenetic characterization using 16S rRNA gene sequencing, PSP 39-04 was closely related with Chromohalobacter salixigens strain DSM3043.

Herbivore Oral Secreted Bacteria Trigger Distinct Defense Responses in Preferred and Non-Preferred Host Plants.

PubMed

Wang, Jie; Chung, Seung Ho; Peiffer, Michelle; Rosa, Cristina; Hoover, Kelli; Zeng, Rensen; Felton, Gary W

2016-06-01

Insect symbiotic bacteria affect host physiology and mediate plant-insect interactions, yet there are few clear examples of symbiotic bacteria regulating defense responses in different host plants. We hypothesized that plants would induce distinct defense responses to herbivore- associated bacteria. We evaluated whether preferred hosts (horsenettle) or non-preferred hosts (tomato) respond similarly to oral secretions (OS) from the false potato beetle (FPB, Leptinotarsa juncta), and whether the induced defense triggered by OS was due to the presence of symbiotic bacteria in OS. Both horsenettle and tomato damaged by antibiotic (AB) treated larvae showed higher polyphenol oxidase (PPO) activity than those damaged by non-AB treated larvae. In addition, application of OS from AB treated larvae induced higher PPO activity compared with OS from non-AB treated larvae or water treatment. False potato beetles harbor bacteria that may provide abundant cues that can be recognized by plants and thus mediate corresponding defense responses. Among all tested bacterial isolates, the genera Pantoea, Acinetobacter, Enterobacter, and Serratia were found to suppress PPO activity in tomato, while only Pantoea sp. among these four isolates was observed to suppress PPO activity in horsenettle. The distinct PPO suppression caused by symbiotic bacteria in different plants was similar to the pattern of induced defense-related gene expression. Pantoea inoculated FPB suppressed JA-responsive genes and triggered a SA-responsive gene in both tomato and horsenettle. However, Enterobacter inoculated FPB eliminated JA-regulated gene expression and elevated SA-regulated gene expression in tomato, but did not show evident effects on the expression levels of horsenettle defense-related genes. These results indicate that suppression of plant defenses by the bacteria found in the oral secretions of herbivores may be a more widespread phenomenon than previously indicated.

Aerogenic Vaccination With a Burkholderia mallei Auxotroph Protects Against Aerosol-Initiated Glanders in Mice

DTIC Science & Technology

2005-03-14

Vaccine 23 (2005) 1986–1992 Aerogenic vaccination with a Burkholderia mallei auxotroph protects against aerosol-initiated glanders in mice Ricky L...October 2004 Available online 11 November 2004 Abstract Burkholderia mallei is an obligate mammalian pathogen that causes the zoonotic disease glanders ... Burkholderia mallei , the causative agent of glanders , is gram-negative bacillus. It is a highly adapted parasite of quines and cannot persist in nature

In situ studies of microbial inactivation during high pressure processing

NASA Astrophysics Data System (ADS)

Maldonado, Jose Antonio; Schaffner, Donald W.; Cuitiño, Alberto M.; Karwe, Mukund V.

2016-01-01

High pressure processing (HPP) has been shown to reduce microbial concentration in foods. The mechanisms of microbial inactivation by HPP have been associated with damage to cell membranes. The real-time response of bacteria to HPP was measured to elucidate the mechanisms of inactivation, which can aid in designing more effective processes. Different pressure cycling conditions were used to expose Enterobacter aerogenes cells to HPP. Propidium iodide (PI) was used as a probe, which fluoresces after penetrating cells with damaged membranes and binding with nucleic acids. A HPP vessel with sapphire windows was used for measuring fluorescence in situ. Membrane damage was detected during pressurization and hold time, but not during depressurization. The drop in fluorescence was larger than expected after pressure cycles at higher pressure and longer times. This indicated possible reversible disassociation of ribosomes resulting in additional binding of PI to exposed RNA under pressure and its release after depressurization.

Study of dynamical process of heat denaturation in optically trapped single microorganisms by near-infrared Raman spectroscopy

NASA Astrophysics Data System (ADS)

Xie, Changan; Li, Yong-qing; Tang, Wei; Newton, Ronald J.

2003-11-01

The development of laser traps has made it possible to investigate single cells and record real-time Raman spectra during a heat-denaturation process when the temperature of the surrounding medium is increased. Large changes in the phenylalanine band (1004 cm-1) of near-infrared spectra between living and heat-treated cells were observed in yeast and Escerichia coli and Enterobacter aerogenes bacteria. This change appears to reflect the change in environment of phenylalanine as proteins within the cells unfold as a result of increasing temperatures. As a comparison, we measured Raman spectra of native and heat-denatured solutions of bovine serum albumin proteins, and a similar change in the phenylalanine band of spectra was observed. In addition, we measured Raman spectra of native and heat-treated solutions of pure phenylalanine molecules; no observable difference in vibrational spectra was observed. These findings may make it possible to study conformational changes in proteins within single cells.

Synthesis and characterization of a series of transition metal complexes with a new symmetrical polyoxaaza macroacyclic Schiff base ligand: X-ray crystal structure of cobalt(II) and nickel(II) complexes and their antibacterial properties

NASA Astrophysics Data System (ADS)

Keypour, Hassan; Shayesteh, Maryam; Rezaeivala, Majid; Chalabian, Firoozeh; Valencia, Laura

2013-01-01

A new symmetrical [N4O2] hexadentate Schiff base ligand, (E)-N-(pyridin-2-ylmethylene)-2-(3-(2-((E)-pyridin-2-lmethyleneamino)phenoxy)naphthalen-2-yloxy)benzenamine, abbreviated to L, and its complexes of Ni(II), Cu(II), Zn(II), Co(II), Cd(II) and Mn(II) have been synthesized in the presence of metal ions. The complexes were structurally characterized by elemental analyses, IR, UV-Vis, NMR and molar conductivity. The crystal structures of two complexes, [NiL(ONO2)2]·2H2O and [CoLCl2]CH3OH·0.5H2O, have been determined by a single crystal X-ray diffraction study. In these complexes, the ligand is coordinated in a neutral form via pyridine and azomethine nitrogen atoms. The metal ions complete their six coordination with two coordinated nitrate or chloride ions, forming a distorted octahedral geometry. The synthesized compounds have antibacterial activity against the three Gram-positive bacteria: Enterococcus faecalis, Bacillus cereus and Staphylococcus epid and also against the three Gram-negative bacteria: Citrobacter freundii, Enterobacter aerogenes and Salmonella typhi. The activity data show that the complexes are more potent antibacterials than the parent Schiff base.

Antibacterial abietane-type diterpenoid, taxodone from Metasequoia glyptostroboides Miki ex Hu.

PubMed

Bajpai, Vivek K; Kang, Sun Chul

2010-12-01

In an attempt to isolate bioactive constituents, ethyl acetate cone extract of Metasequoia glyptostroboides was subjected to a column chromatographic analysis that resulted in isolation of an abietane-type diterpenoid, taxodone. Its structure was elucidated by spectroscopic means. Further, taxodone showed potential antibacterial effect as diameters of zones of inhibition against foodborne pathogenic bacteria, such as Listeria monocytogenes ATCC 19166, Salmonella typhimurium KCTC 2515, S. enteritidis KCTC 2021, Escherichia coli ATCC 8739, E. coli O157:H7 ATCC 43888, Enterobacter aerogenes KCTC 2190, Staphylococcus aureus ATCC 6538 and S. aureus KCTC 1916, were found in the range of 9.4 to 14.2 mm. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of taxodone against the employed bacterial pathogens were found in the range of 250 to 1000 and 250 to less than 2000 microg/ml, respectively. Also the compound had a strong antibacterial effect on the viable counts of the tested bacteria. These findings indicate that the bioactive compound taxodone present in M. glyptostroboides could be used as an antibacterial agent in food industry to inhibit the growth of certain important foodborne pathogens.

Management of risk of microbial cross-contamination from uncooked frozen hamburgers by alcohol-based hand sanitizer.

PubMed

Schaffner, Donald W; Schaffner, Kristin M

2007-01-01

This research was undertaken to determine the effectiveness of an alcohol-based hand sanitizer on hands contaminated with a nonpathogen surrogate for Escherichia coli O157:H7, where the source of the contamination was frozen hamburger patties. A nonpathogenic nalidixic acid-resistant food-grade strain of Enterobacter aerogenes was used to inoculate frozen hamburger patties composed of 76% lean beef and 24% fat. Thirty-two individuals participated to produce the data used in this study. Each participant handled nine patties at least three times, a sample for microbiological analysis was collected from the surface of one hand, the participant sanitized both hands, and a sample was collected from the other hand. Burger handling created perceptible and visible food debris on the hands of most participants. Computer simulations also were used to perform a variety of risk calculations. The average reduction in bacteria from the use of sanitizer on hands contaminated by frozen burgers containing E. aerogenes was 2.6 +/- 0.7 log CFU per hand. An experiment designed to simultaneously test the effect of sanitizer on E. aerogenes and E. coli O157:H7 also revealed no significant difference in sanitizer effectiveness against the two organisms. The results of the real-world risk estimation calculations (using the actual prevalence and concentration of E. coli O157:H7 in ground beef) predict that once in 1 million trials, a single pathogen cell will be transferred to a single lettuce piece. The effectiveness of this sanitizer intervention was similar to that for hand washing and glove use previously reported. The person-to-person microbial reduction variability from sanitizer use is similar to published data for glove use and was less variable than published data on hand washing effectiveness.

Clinical analysis of Enterobacter bacteremia in pediatric patients: a 10-year study.

PubMed

Chen, Hui-Lan; Lu, Jen-Her; Wang, Hsin-Hui; Chen, Shu-Jen; Chen, Chun-Jen; Wu, Keh-Gong; Tang, Ren-Bin

2014-10-01

Enterobacter species has emerged as an important pathogen of nosocomial bacteremia. The purpose of this study is to review the clinical characteristics of bacteremia in pediatric patients. We reviewed retrospectively the medical records of patients (under the age of 18 years) having Enterobacter bacteremia who were treated at Taipei the Veterans General Hospital from January 2001 to June 2011. In total, 853 positive blood cultures were obtained from 620 patients during the study period. Among them, 96 episodes of Enterobacter bacteremia were found in 83 patients, accounting for 11.3% of all bacteremia. Eighty-two cases (98.8%) were nosocomial infections. Most of the cases were neonates (62 cases, 74.7%) and premature infants (51 cases, 61.5%). The common sources of bacteremia were the respiratory tract (53.0%), followed by intravascular catheter (10.8%), multiple sources (10.8%), and the gastrointestinal tract (8.4%). The overall case fatality rate was 18.1%, with the highest rate being reported among premature infants. The factors responsible for the deaths were leukocytosis and a higher median number of underlying diseases. Based on the findings of the present study, it can be concluded that Enterobacter species are probably an important pathogen of nosocomial bacteremia in premature neonates. The number of underlying diseases should be considered a major factor influencing the prognosis. Copyright © 2013. Published by Elsevier B.V.

Phytate degradation by fungi and bacteria that inhabit sawdust and coffee residue composts.

PubMed

Fathallh Eida, Mohamed; Nagaoka, Toshinori; Wasaki, Jun; Kouno, Kenji

2013-01-01

Phytate is the primary source of organic phosphorus, but it cannot be directly utilized by plants and is strongly adsorbed by the soil, reducing bioavailability. Composting is a process used to improve the bioavailability of phytate in organic wastes through degradation by microorganisms. In this study, we aimed to investigate the phytate-degrading ability of fungi and bacteria that inhabit sawdust compost and coffee residue compost, and their contribution to the composting process. In the plate assay, the fungi that formed clear zones around their colonies belonged to the genera Mucor, Penicillium, Galactomyces, Coniochaeta, Aspergillus, and Fusarium, while the bacteria belonged to the genera Pseudomonas, Enterobacter, Chitinophaga, and Rahnella. Eight fungal isolates (genera Mucor, Penicillium, Galactomyces, and Coniochaeta) and four bacterial isolates (genera Pseudomonas, Enterobacter, and Rahnella) were selected to evaluate phytase activity in their liquid culture and their ability to degrade phytate in organic materials composed of mushroom media residue and rice bran. The selected fungi degraded phytate in organic materials to varying degrees. Penicillium isolates showed the highest degradation ability and Coniochaeta isolate exhibited relatively high degradation ability. The clear zone diameters of these fungal isolates displayed significantly positive and negative correlations with inorganic and phytate phosphorus contents in the organic materials after incubation, respectively; however, none of the selected bacteria reduced phytate phosphorus in organic materials. It is therefore possible that fungi are major contributors to phytate degradation during composting.

Phytate Degradation by Fungi and Bacteria that Inhabit Sawdust and Coffee Residue Composts

PubMed Central

Eida, Mohamed Fathallh; Nagaoka, Toshinori; Wasaki, Jun; Kouno, Kenji

2013-01-01

Phytate is the primary source of organic phosphorus, but it cannot be directly utilized by plants and is strongly adsorbed by the soil, reducing bioavailability. Composting is a process used to improve the bioavailability of phytate in organic wastes through degradation by microorganisms. In this study, we aimed to investigate the phytate-degrading ability of fungi and bacteria that inhabit sawdust compost and coffee residue compost, and their contribution to the composting process. In the plate assay, the fungi that formed clear zones around their colonies belonged to the genera Mucor, Penicillium, Galactomyces, Coniochaeta, Aspergillus, and Fusarium, while the bacteria belonged to the genera Pseudomonas, Enterobacter, Chitinophaga, and Rahnella. Eight fungal isolates (genera Mucor, Penicillium, Galactomyces, and Coniochaeta) and four bacterial isolates (genera Pseudomonas, Enterobacter, and Rahnella) were selected to evaluate phytase activity in their liquid culture and their ability to degrade phytate in organic materials composed of mushroom media residue and rice bran. The selected fungi degraded phytate in organic materials to varying degrees. Penicillium isolates showed the highest degradation ability and Coniochaeta isolate exhibited relatively high degradation ability. The clear zone diameters of these fungal isolates displayed significantly positive and negative correlations with inorganic and phytate phosphorus contents in the organic materials after incubation, respectively; however, none of the selected bacteria reduced phytate phosphorus in organic materials. It is therefore possible that fungi are major contributors to phytate degradation during composting. PMID:23100024

The preliminary assessment of anti-microbial activity of HPLC separated components of Kirkia wilmsii.

PubMed

Chigayo, K; Mojapelo, P E L; Bessong, P; Gumbo, J R

2014-01-01

Most communities in developing countries rely on traditional medicines for the treatment of diseases. In South Africa, the Limpopo province, within the Lebowakgomo district, uses tuberous roots of Kirkia wilmsii, after infusion in water for the treatment of a wide range of diseases by Sotho communities. The main objective of the study was to assess the anti-microbial activity of separated aqueous components of the Kirkia wilmsii tuberous roots. The clear aqueous extracts that were obtained after a 0.45 µm membrane filtration (Millipore Millex-HV Hydrophillic PVDF filter), were then injected into a preparative high performance liquid chromatography instrument in which pure components, as shown by peaks, were collected and evaluated for anti-microbial activity against a range of microorganisms. The eight separated components were obtained, out of which four components showed anti-microbial activity (AMA). The freeze dried components were re-dissolved in deionised water and then evaluated for AMA against Vibrio cholerae, Shigella dysenteriae, Aeromonas hydrophilia, Salmonella typhi Proteus mirabilis, Escherichia coli, Staphylococcus aureus, Candida albicans and Enterobacter aerogenes. Component one exhibited antimicrobial activity against Shigella dysenteriae, Aeromonas hydrophilia, Salmonella typhi, Proteus mirabilis, Escherichia coli and Staphylococcus aureus with a minimum inhibitory concentration (MIC), of 3.445 mg/ml. Component five was only active against Proteus mirabilis with a MIC of 0.08 mg/ml. Component 7, was active against Shigella dysenteriae, Staphylococcus aureus and Escherichia coli with a MIC of 0.365 mg/ml against both Shigella dysenteriae and Staphylococcus aureus and 0.091 mg/ml against Escherichia coli. Component 8, was active against Shigella, Aeromonas hydrophilia, Salmonella, Proteus mirabilis, Escherichia coli with a MIC of 155 mg/ml. Only four out of eight aqueous extracts showed AMA against both gram negative and positive bacteria and

Detection of extended-spectrum β-lactamase in Enterobacter spp.--evaluation of six phenotypic tests.

PubMed

Nogueira-Miranda, Keite da Silva; Palmeiro, Jussara Kasuko; Conte, Danieli; Maia, Fernanda Valverde; Reason, Iara Taborda de Messias; Monteiro, Cristina Leise; Dalla-Costa, Libera Maria

2012-02-01

Extended-spectrum β-lactamases (ESBL) are plasmid-mediated enzymes that hydrolyze cephalosporins and monobactams. The lack of a standard method to detect ESBL in Enterobacter spp. has led to underestimating its frequency. The aim of this study was to evaluate ESBL detection in Enterobacter spp. By the double-disk synergy test (DDST) and combined disk test (CDT) assay using cefepime, cefotaxime, and ceftazime as substrates for ESBL, plus AmpC inhibitors in different associations. A total of 83 Enterobacter spp. ESBL and 31 non-ESBL Enterobacter spp. were tested, and a cutoff point ≥3 mm was defined using a receiver operating characteristic (ROC) curve for combined disc methods. All tests showed 100% specificity. The sensitivity was 89.2% for DDST and CDT without AmpC inibitor, 90.4% in the combined disc test in Mueller-Hinton agar containing phenylboronic acid (CDT-PBAA), and 94% in the combined disc test in Mueller-Hinton agar containing cloxacillin (CDT-CLXA). Cefepime was the best substrate, mainly when AmpC inhibitors were not used. However, superior results were achieved when all cephalosporins were evaluated together. In conclusion, to improve ESBL detection in Enterobacter spp., some modifications in phenotypic tests are needed, such as to reduce the distance between the discs to 20 mm in DDST, to use a cutoff point for ≥3 mm on the CDT, and to include a cefepime disk or an inhibitor of AmpC in all tests.

Risk Factors for Emergence of Resistance to Broad-Spectrum Cephalosporins among Enterobacter spp.

PubMed Central

Kaye, Keith S.; Cosgrove, Sara; Harris, Anthony; Eliopoulos, George M.; Carmeli, Yehuda

2001-01-01

Among 477 patients with susceptible Enterobacter spp., 49 subsequently harbored third-generation cephalosporin-resistant Enterobacter spp. Broad-spectrum cephalosporins were independent risk factors for resistance (relative risk [OR] = 2.3, P = 0.01); quinolone therapy was protective (OR = 0.4, P = 0.03). There were trends toward decreased risk for resistance among patients receiving broad-spectrum cephalosporins and either aminoglycosides or imipenem. Of the patients receiving broad-spectrum cephalosporins, 19% developed resistance. PMID:11502540

Fermentation of polysaccharides by Klebsiella and other facultative bacilli

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ochuba, G.U.; Von Riesen, V.L.

1980-05-01

Fermentations of 10 polysaccharides by species of the family Enterobacteriaceae were examined. Algin, guar, karaya, xanthan, and xylan were not fermented by any of the strains tested. Most of the activity was found in the tribe Klebsielleae. Klebseilla oxytoca fermented amylopectin (97% of the strains studied), carrageenan (100%), inulin (68%), polypectate (100%), and tragacanth (100%). Klebsiella pneumoniae fermented amylopectin (91%), carrageenan (100%), and tragacanth (86%). Carraggeenan was also fermented by Enterobacter aerogenes (100%), Enterobacter agglomerans (63%), Enterobacter cloacae (95%), and pectobacterium (38%). pectobacterium shared polypectate fermentation (100%) with K. oxytoca. With one exception, Serratia strains were negative on all polysaccharides.more » These results, along with other evidence, indicate that (i) the genus Klebsiella is biochemically the most versatile genus of the tribe, (ii) because of its distinct characteristics, K. oxytoca warrants species designation separate from K. pneumoniae, and (iii) some food additives generally considered indigestible can be metabolized by a few species of facultative bacilli, whereas others appear to be resistant.« less

UV light tolerance and reactivation potential of tetracycline-resistant bacteria from secondary effluents of a wastewater treatment plant.

PubMed

Huang, Jing-Jing; Xi, Jinying; Hu, Hong-Ying; Li, Yi; Lu, Sun-Qin; Tang, Fang; Pang, Yu-Chen

2016-03-01

Tetracycline-resistant bacteria (TRB) are of concern as emerging microbial contaminants in reclaimed water. To understand the effects of UV disinfection on TRB, both inactivation and reactivation profiles of TRB, as well as 16 tetracycline-resistant isolates from secondary effluent, were characterized in this study. The inactivation ratio of TRB was significantly lower (3.0-log) than that of heterotrophic bacteria (>4.0-log) in the secondary effluent. Additionally, the proportion of TRB significantly increased from 1.65% to 15.51% under 20mJ/cm(2) ultraviolet (UV) exposure. The inactivation rates of tetracycline-resistant isolates ranged from 0.57/s to 1.04/s, of which tetracycline-resistant Enterobacter-1 was the most tolerant to UV light. The reactivation of TRB, tetracycline-resistant isolated strains, as well as heterotrophic bacteria commonly occurred in the secondary effluent even after 20mJ/cm(2) UV exposure. The colony forming ability of TRB and heterotrophic bacteria reached 3.2-log and 3.0-log under 20mJ/cm(2) UV exposure after 22hr incubation. The final inactivation ratio of tetracycline-resistant Enterobacter-1 was 1.18-log under 20mJ/cm(2) UV exposure after 22hr incubation, which is similar to those of TRB (1.18-log) and heterotrophic bacteria (1.19-log). The increased proportion of TRB and the reactivation of tetracycline-resistant enterobacteria in reclaimed water could induce a microbial health risk during wastewater reuse. Copyright © 2015. Published by Elsevier B.V.

Prevalence of bovine subclinical mastitis, its etiology and diagnosis of antibiotic resistance of dairy farms in four municipalities of a tropical region of Mexico.

PubMed

Olivares-Pérez, Jaime; Kholif, Ahmed Eid; Rojas-Hernández, Saul; Elghandour, Mona Mohamed Mohamed Yasseen; Salem, Abdelfattah Zeidan Mohamed; Bastida, Adrian Zaragoza; Velázquez-Reynoso, David; Cipriano-Salazar, Moisés; Camacho-Díaz, Luis Miguel; Alonso-Fresán, María Uxúa; DiLorenzo, Nicolas

2015-12-01

A region-wide survey was conducted in the tropical area of Tierra Caliente, State of Guerrero, Mexico to estimate the prevalence of subclinical bovine mastitis (SCM), distribution of mastitis pathogens, and in vitro antimicrobial susceptibility of different mastitis pathogens in dairy farms. In total, 1036 quarter milk samples were obtained from 259 cows at 87 different dairy farms. Collected quarter milk samples were submitted for California Mastitis Test (CMT), bacteriological examination, and testing for antimicrobial susceptibility. Overall prevalence of SCM in the studied area was 20.5 %. Prevalence in the different regions was as follows: 28 % in Arcelia municipality, 21 % in Tlalchapa municipality, 19.4 % in Pungarabato municipality, and 14.3 % in Finch Cutzamala municipality. Of all positive isolates, 97.5 % were Gram-negative bacteria. Moreover, of all positive isolates, 37.5 % were Proteus vulgaris, 25 % Salmonella spp., 12.5 % Enterobacter aerogenes, and 10 % Escherichia coli. Klebsiella pneumonia and E. coli were sensitive for netilmicin antimicrobial. However, E. coli was sensitive for pefloxacin and gentamicin with a sensitivity for pefloxacin for E. aerogenes, while Staphylococci were sensitive for gentamicin and dicloxacillin. It could be concluded that practices such as the implementation of mastitis control programs, improved milking hygiene together with an intramammary treatment with netilmicin, pefloxacin, and gentamicin antimicrobials should be considered for mastitis prevention in the study area of Tierra Caliente, in the tropical area of Guerrero, Mexico.

Identity and Behavior of Xylem-Residing Bacteria in Rough Lemon Roots of Florida Citrus Trees †

PubMed Central

Gardner, John M.; Feldman, Albert W.; Zablotowicz, Robert M.

1982-01-01

An aseptic vacuum extraction technique was used to obtain xylem fluid from the roots of rough lemon (Citrus jambhiri Lush.) rootstock of Florida citrus trees. Bacteria were consistently isolated from vascular fluid of both healthy and young tree decline-affected trees. Thirteen genera of bacteria were found, the most frequently occurring genera being Pseudomonas (40%), Enterobacter (18%), Bacillus, Corynebacterium, and other gram-positive bacteria (16%), and Serratia (6%). Xylem bacterial counts fluctuated seasonally. Bacterial populations ranged from 0.1 to 22 per mm3 of root tissue (about 102 to 2 × 104 bacteria per g of xylem) when bacterial counts were made on vascular fluid, but these numbers were 10- to 1,000-fold greater when aseptically homogenized xylem tissue was examined similarly. Some of the resident bacteria (4%) are potentially phytopathogenic. It is proposed that xylem bacteria have an important role in the physiology of citrus. PMID:16346030

A computational study on the strength and nature of bifurcated aerogen bonds

NASA Astrophysics Data System (ADS)

Esrafili, Mehdi D.; Sadr-Mousavi, Asma

2018-04-01

A quantum chemical study is performed to unveil the strength and bonding properties of bifurcated aerogen-bonding (BAB) interactions in complexes formed between ZO3 molecules (Z = Ar, Kr and Xe) and 1,2-dihydroxybenzene derivatives. The interaction energies of the resulting complexes are between -7.70 and -15.59 kcal/mol. The nature of BAB interactions is identified by the molecular electrostatic potential, quantum theory of atoms in molecules, noncovalent interaction index and natural bond orbital analyses. The mutual influence between the BAB and a halogen, chalcogen, pnicogen or tetrel bonding interaction is also studied in systems where these interactions coexist.

Characterisation of manganese peroxidase and laccase producing bacteria capable for degradation of sucrose glutamic acid-Maillard reaction products at different nutritional and environmental conditions.

PubMed

Kumar, Vineet; Chandra, Ram

2018-02-02

Maillard reactions products (MRPs) are a major colorant of distillery effluent. It is major source of environmental pollution due to its complex structure and recalcitrant nature. This study has revealed that sucrose glutamic acid-Maillard reaction products (SGA-MRPs) showed many absorption peaks between 200 and 450 nm. The absorption maximum peak was noted at 250 nm in spectrophotometric detection. This indicated the formation of variable molecular weight Maillard products during the SGA-MRPs formation at high temperature. The identified aerobic bacterial consortium consisting Klebsiella pneumoniae (KU726953), Salmonella enterica (KU726954), Enterobacter aerogenes (KU726955), Enterobacter cloaceae (KU726957) showed optimum production of MnP and laccase at 120 and 144 h of growth, respectively. The potential bacterial consortium showed decolourisation of Maillard product up to 70% in presence of glucose (1%), peptone (0.1%) at optimum pH (8.1), temperature (37 °C) and shaking speed (180 rpm) within 192 h of incubation. The reduction of colour of Maillard product correlated with shifting of absorption peaks in UV-Vis spectrophotometry analysis. Further, the changing of functional group in FT-IR data showed appearance of new peaks and GC-MS analysis of degraded sample revealed the depolymerisation of complex MRPs. The toxicity evaluation using seed of Phaseolus mungo L. showed reduction of toxicity of MRPs after bacterial treatment. Hence, this study concluded that developed bacterial consortium have capability for decolourisation of MRPs due to high content of MnP and laccase.

The Complex Epidemiology of Carbapenem-Resistant Enterobacter Infections: A Multicenter Descriptive Analysis.

PubMed

Lazarovitch, Tsilia; Amity, Keren; Coyle, Joseph R; Ackerman, Benjamin; Tal-Jasper, Ruthy; Ofer-Friedman, Hadas; Hayakawa, Kayoko; Bogan, Christopher; Lephart, Paul R; Kaplansky, Tamir; Maskit, Moran; Azouri, Tal; Zaidenstein, Ronit; Perez, Federico; Bonomo, Robert A; Kaye, Keith S; Marchaim, Dror

2015-11-01

The pandemic of carbapenem-resistant Enterobacteriaceae (CRE) was primarily due to clonal spread of bla KPC producing Klebsiella pneumoniae. Thus, thoroughly studied CRE cohorts have consisted mostly of K. pneumoniae. To conduct an extensive epidemiologic analysis of carbapenem-resistant Enterobacter spp. (CREn) from 2 endemic and geographically distinct centers. CREn were investigated at an Israeli center (Assaf Harofeh Medical Center, January 2007 to July 2012) and at a US center (Detroit Medical Center, September 2008 to September 2009). bla KPC genes were queried by polymerase chain reaction. Repetitive extragenic palindromic polymerase chain reaction and pulsed-field gel electrophoresis were used to determine genetic relatedness. In this analysis, 68 unique patients with CREn were enrolled. Sixteen isolates (24%) were from wounds, and 33 (48%) represented colonization only. All isolates exhibited a positive Modified Hodge Test, but only 93% (27 of 29) contained bla KPC. Forty-three isolates (63%) were from elderly adults, and 5 (7.4%) were from neonates. Twenty-seven patients died in hospital (40.3% of infected patients). Enterobacter strains consisted of 4 separate clones from Assaf Harofeh Medical Center and of 4 distinct clones from Detroit Medical Center. In this study conducted at 2 distinct CRE endemic regions, there were unique epidemiologic features to CREn: (i) polyclonality, (ii) neonates accounting for more than 7% of cohort, and (iii) high rate of colonization (almost one-half of all cases represented colonization). Since false-positive Modified Hodge Tests in Enterobacter spp. are common, close monitoring of carbapenem resistance mechanisms (particularly carbapenemase production) among Enterobacter spp. is important.

Seed-vectored endophytic bacteria modulate development of rice seedlings.

PubMed

Verma, S K; Kingsley, K; Irizarry, I; Bergen, M; Kharwar, R N; White, J F

2017-06-01

The aim of the present study was to evaluate the effects of the removal of indigenous bacteria from rice seeds on seedling growth and development. Here we report the presence of three indigenous endophytic bacteria in rice seeds that play important roles in modulating seedling development (shoot and root lengths, and formation of root hairs and secondary roots) and defence against pathogens. Seed-associated bacteria were removed using surface sterilization with NaOCl (bleach) followed by antibiotic treatment. When bacteria were absent, growth of seedlings in terms of root hair development and overall seedling size was less than that of seedlings that contained bacteria. Reactive oxygen staining of seedlings showed that endophytic bacteria became intracellular in root parenchyma cells and root hairs. Roots containing endophytic bacteria were seen to stain densely for reactive oxygen, while roots free of bacteria stained lightly for reactive oxygen. Bacteria were isolated and identified as Enterobacter asburiae (VWB1), Pantoea dispersa (VWB2) and Pseudomonas putida (VWB3) by 16S rDNA sequencing. Bacteria were found to produce indole acetic acid (auxins), inhibited the pathogen Fusarium oxysporum and solubilized phosphate. Reinoculation of bacteria onto seedlings derived from surface-disinfected rice and Bermuda grass seeds significantly restored seedling growth and development. Rice seeds harbour indigenous bacterial endophytes that greatly influence seedling growth and development, including root and shoot lengths, root hair formation and disease susceptibility of rice seedlings. This study shows that seeds of rice naturally harbour bacterial endophytes that play key roles in modulation of seedling development. © 2017 The Society for Applied Microbiology.

Antimicrobial activity of Schinus lentiscifolius (Anacardiaceae).

PubMed

Gehrke, Ilaine T S; Neto, Alexandre T; Pedroso, Marcelo; Mostardeiro, Clarice P; Da Cruz, Ivana B M; Silva, Ubiratan F; Ilha, Vinicius; Dalcol, Ionara I; Morel, Ademir F

2013-07-09

Schinus lentiscifolius Marchand (syn. Schinus weinmannifolius Engl) is a plant native to Rio Grande do Sul (Southern Brazil) and has been used in Brazilian traditional medicine as antiseptic and antimicrobial for the treatment of many different health problems as well as to treat leucorrhea and to assist in ulcer and wound healing. Although it is a plant widely used by the population, there are no studies proving this popular use. The crude aqueous extract, the crude neutral methanol extract, fractions prepared from this extract (n-hexane, ethyl acetate, and n-butanol), pure compounds isolated from these fractions, and derivatives were investigated in vitro for antimicrobial activities against five Gram positive bacteria: Bacillus subtilis, Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus saprophyticus, Streptococcus pyogenes, three Gram negative bacteria: Escherichia coli, Pseudomonas aeruginosa, and Shigella sonnei, and four yeasts: Candida albicans, Candida tropicalis, Cryptococcus neoformans, and Saccharomyces cerevisiae. The isolated compound moronic acid, which is the most active, was tested against a range of other bacteria such as two Gram positive bacteria, namely, Bacillus cereus, Enterococcus spp, and six Gram negative bacteria, namely, Burkholderia cepacia, Providencia stuartii, Morganella morganii, Enterobacter cloacae, Enterobacter aerogenes, and Proteus mirabilis. The leaf aqueous extract (decoction) of Schinus lentiscifolius showed a broad spectrum of antibacterial activity, ranging from 125 to 250 μg/ml (MIC) against the tested bacteria and fungi. The n-hexane extract, despite being very little active against bacteria, showed an excellent antifungal activity, especially against Candida albicans (MIC=25 μg/ml), Candida tropicalis (MIC=15.5 μg/ml), and Cryptococcus neoformans, (MIC=15.5 μg/ml). From the acetate fraction (the most active against bacteria), compounds 1-6 were isolated: nonadecanol (1), moronic acid (2), gallic acid

Biodegradation of dichlorodiphenyltrichloroethane: intermediates in dichlorodiphenylacetic acid metabolism by aerobacter aerogenes

USGS Publications Warehouse

Wedemeyer, Gary

1967-01-01

The final product of dichlorodiphenyltrichloroethane (DDT) degradation by vertebrates is commonly considered to be dichlorodiphenylacetic acid, DDA. Recently, certain organisms have been found to degrade further DDA to dichlorobenzophenone (DBP), but the possibility that such degradation was due to microbial action could not be excluded. Significantly, dichlorobenzhydrol (DBH), dichlorophenylmethane (DPM), and dichlorodiphenylethylene (DDE) have been tentatively identified in rats fed DDA. Since DDA as well as DDT is degraded by the ubiquitous microorganism Aerobacter aerogenes, it seemed reasonable that the intestinal microflora might be involved in DBP formation, DPM and DBH being intermediates in its pathway from DDA. Since DDA is a (3,y-unsaturated acid, ketone formation via an alkene and an alcohol would be expected.

Adequate Hand Washing and Glove Use Are Necessary To Reduce Cross-Contamination from Hands with High Bacterial Loads.

PubMed

Robinson, Andrew L; Lee, Hyun Jung; Kwon, Junehee; Todd, Ewen; Rodriguez, Fernando Perez; Ryu, Dojin

2016-02-01

Hand washing and glove use are the main methods for reducing bacterial cross-contamination from hands to ready-to-eat food in a food service setting. However, bacterial transfer from hands to gloves is poorly understood, as is the effect of different durations of soap rubbing on bacterial reduction. To assess bacterial transfer from hands to gloves and to compare bacterial transfer rates to food after different soap washing times and glove use, participants' hands were artificially contaminated with Enterobacter aerogenes B199A at ∼9 log CFU. Different soap rubbing times (0, 3, and 20 s), glove use, and tomato dicing activities followed. The bacterial counts in diced tomatoes and on participants' hands and gloves were then analyzed. Different soap rubbing times did not significantly change the amount of bacteria recovered from participants' hands. Dicing tomatoes with bare hands after 20 s of soap rubbing transferred significantly less bacteria (P < 0.01) to tomatoes than did dicing with bare hands after 0 s of soap rubbing. Wearing gloves while dicing greatly reduced the incidence of contaminated tomato samples compared with dicing with bare hands. Increasing soap washing time decreased the incidence of bacteria recovered from outside glove surfaces (P < 0.05). These results highlight that both glove use and adequate hand washing are necessary to reduce bacterial cross-contamination in food service environments.

[Expression and characterization of a neutral Enterobacter cloacae GX-3 invertase].

PubMed

Zhao, Yingli; Wu, Qianqian; Zhang, Zhikai; Wang, Zilong; Wei, Yutuo; Huang, Ribo; Du, Liqin

2015-04-04

To characterize a neutral invertase from Enterobacter cloacae GX-3. By searching GenBank database, we found the genes encoding invertase from the same genus Enterobacter. These sequences were aligned and analyzed. Then, a gene encoding neutral invertase was amplified by PCR. The recombinant plasmid pQE-Einv was constructed. We purified the expressed protein Einv with nickel-nitrilotriacetic acid chromatography. At last, the characterics of the recombinant protein Einv were studied in detail. A gene encoding neutral invertase was discovered and cloned from E. cloacae GX-3. The recombinant enzyme Einv was characterized. Einv had an optimum pH of 6.5 and an optimum temperature of 40 degrees C. The results of sodium dodecyl sulfate polyacrylamide gel electropheresis (SDS-PAGE) and gel permeation chromatography ( GPC) showed that Einv was a homo-dimer protein. Einv retained 80% activity at sucrose concentrations up to 1170 mmol/L. But, Einv had no transglycosylation activity at high sucrose concentration. It could hydrolyze raffinose, 1-kestose, nystose, fructofuranosylnystose and stachyose. It is first reported that an invertase from Enterobacter cloacae is a beta-fructofuranosidase at neutral pH range. It only has hydrolysis activity without tranglycosylation activity. These characteristics indicate that the neutral invertase Einv has important applications in food industry.

The waaL gene mutation compromised the inhabitation of Enterobacter sp. Ag1 in the mosquito gut environment.

PubMed

Pei, Dong; Jiang, Jinjin; Yu, Wanqin; Kukutla, Phanidhar; Uentillie, Alejandro; Xu, Jiannong

2015-08-27

The mosquito gut harbors a variety of bacteria that are dynamically associated with mosquitoes in various contexts. However, little is known about bacterial factors that affect bacterial inhabitation in the gut microbial community. Enterobacter sp. Ag1 is a predominant Gram negative bacterium in the mosquito midgut. In a mutant library that was generated using transposon Tn5-mediated mutagenesis, a mutant was identified, in which the gene waaL was disrupted by the Tn5 insertion. The waaL encodes O antigen ligase, which is required for the attachment of O antigen to the outer core oligosaccharide of the lipopolysaccharide (LPS). The waaL(-) mutation caused the O antigen repeat missing in the LPS. The normal LPS structure was restored when the mutant was complemented with a plasmid containing waaL gene. The waaL(-) mutation did not affect bacterial proliferation in LB culture, the mutant cells grew at a rate the same as the wildtype (wt) cells. However, when waaL(-) strain were co-cultured with the wt strain or complemented strain, the mutant cells proliferated with a slower rate, indicating that the mutants were less competitive than wt cells in a community setting. Similarly, in a co-feeding assay, when fluorescently tagged wt strain and waaL(-) strain were orally co-introduced into the gut of Anopheles stephensi mosquitoes, the mutant cells were less prevalent in both sugar-fed and blood-fed guts. The data suggest that the mutation compromised the bacterial inhabitation in the gut community. Besides, the mutant was more sensitive to oxidative stress, demonstrated by lower survival rate upon exposure to 20 mM H₂O₂. Lack of the O antigen structure in LPS of Enterobacter compromised the effective growth in co-culture and co-feeding assays. In addition, O-antigen was involved in protection against oxidative stress. The findings suggest that intact LPS is crucial for the bacteria to steadily stay in the gut microbial community.

Metabolism of the /sup 18/O-methoxy substituent of 3-methoxybenzoic acid and other unlabeled methoxybenzoic acids by anaerobic bacteria. [Eubacterium limosum; Acetobacterium woodil; Syntrophococcus; Clostridium; Desulfotomaculum; Enterobacter

DOE Office of Scientific and Technical Information (OSTI.GOV)

DeWeerd, J.A.; Saxena, A.; Nagle, D.P. Jr.

1988-05-01

The mechanism of the bioconversion of methoxylated benzoic acids to the hydroxylated derivatives was investigated with a model substrate and cultures of one anaerobic consortium, eight strict anaerobic bacteria, and one facultative anaerobic microorganism. We found that a haloaromatic dehalogenating consortium, a dehalogenating isolate from that consortium, Eubacterium, limosum, and a strain of Acetobacterium woodii metabolized 3-(methoxy-/sup 18/O)methoxybenzoic acid (3-anisic acid) to 3-(hydroxy-/sup 18/O)hydroxybenzoic acid stoichiometrically at rates of 1.5, 3.2, 52.4, and 36.7 nmol/min per mg of protein, respectively. A different strain of Acetobacterium and strains of Syntrophococcus, Clostridium Desulfotomaculum, Enterobacter, and an anaerobic bacterium, strain TH-001, were unablemore » to transform this compound. The O-demethylating ability of E. limosum was induced only with appropriate methoxylated benzoates but not with D-glucose, lactate, isoleucine, or methanol. Cross-acclimation and growth experiments with E. limosum showed a rate of metabolism that was an order of magnitude slower and showed no growth with either 4-methoxysalicylic acid (2-hydroxy-4-methoxybenzoic acid) or 4-anisic acid (4-methoxybenzoic acid) when adapted to 3-anisic acid. However, A. woodii NZva-16 showed slower rates and no growth with 3- or 4-methoxysalicylic acid when adapted to 3-anisic acid in similar experiments.« less

Cefepime vs other antibacterial agents for the treatment of Enterobacter species bacteremia.

PubMed

Siedner, Mark J; Galar, Alicia; Guzmán-Suarez, Belisa B; Kubiak, David W; Baghdady, Nour; Ferraro, Mary Jane; Hooper, David C; O'Brien, Thomas F; Marty, Francisco M

2014-06-01

Carbapenems are recommended for treatment of Enterobacter infections with AmpC phenotypes. Although isolates are typically susceptible to cefepime in vitro, there are few data supporting its clinical efficacy. We reviewed all cases of Enterobacter species bacteremia at 2 academic hospitals from 2005 to 2011. Outcomes of interest were (1) persistent bacteremia ≥1 calendar day and (2) in-hospital mortality. We fit logistic regression models, adjusting for clinical risk factors and Pitt bacteremia score and performed propensity score analyses to compare the efficacy of cefepime and carbapenems. Three hundred sixty-eight patients experienced Enterobacter species bacteremia and received at least 1 antimicrobial agent, of whom 52 (14%) died during hospitalization. Median age was 59 years; 19% were neutropenic, and 22% were in an intensive care unit on the day of bacteremia. Twenty-nine (11%) patients had persistent bacteremia for ≥1 day after antibacterial initiation. None of the 36 patients who received single-agent cefepime (0%) had persistent bacteremia, as opposed to 4 of 16 (25%) of those who received single-agent carbapenem (P < .01). In multivariable models, there was no association between carbapenem use and persistent bacteremia (adjusted odds ratio [aOR], 1.52; 95% CI, .58-3.98; P = .39), and a nonsignificant lower odds ratio with cefepime use (aOR, 0.52; 95% CI, .19-1.40; P = .19). In-hospital mortality was similar for use of cefepime and carbapenems in adjusted regression models and propensity-score matched analyses. Cefepime has a similar efficacy as carbapenems for the treatment of Enterobacter species bacteremia. Its use should be further explored as a carbapenem-sparing agent in this clinical scenario.

Identification of gram-negative and gram-positive bacteria by fluorescence studies

NASA Astrophysics Data System (ADS)

Demchak, Jonathan; Calabrese, Joseph; Tzolov, Marian

2011-03-01

Several type strains of bacteria including Vibrio fischeri, Azotobacter vinelandii, Enterobacter cloacae, and Corynebacterium xerosis, were cultured in the laboratory following standard diagnostic protocol based on their individual metabolic strategies. The bacterial cultures were not further treated and they were studied in their pristine state (pure culture - axenic). The fluorescent studies were applied using a continuous wave and a pulsed excitation light sources. Emission and excitation spectra were recorded for the continuous wave excitation and they all show similar spectral features with the exception of the gram positive bacteria showing vibronic structures. The vibrational modes involved in these vibronic bands have energy typical for carbon-carbon vibrations. The fluorescence is quenched in addition of water, even a very thin layer, which confirms that the observed spectral features originate from the outer parts of the bacteria. These results allow to conclude that the fluorescence spectroscopy can be used as a method for studying the membranes of the bacteria and eventually to discriminate between gram positive and gram negative bacteria. The pulsed experiments show that the fluorescence lifetime is in the sub-microsecond range. The results indicate that the observed spectra are superposition of the emission with different lifetimes.

Antimicrobial Activities of Bacteria Associated with the Brown Alga Padina pavonica

PubMed Central

Ismail, Amel; Ktari, Leila; Ahmed, Mehboob; Bolhuis, Henk; Boudabbous, Abdellatif; Stal, Lucas J.; Cretoiu, Mariana Silvia; El Bour, Monia

2016-01-01

Macroalgae belonging to the genus Padina are known to produce antibacterial compounds that may inhibit growth of human- and animal pathogens. Hitherto, it was unclear whether this antibacterial activity is produced by the macroalga itself or by secondary metabolite producing epiphytic bacteria. Here we report antibacterial activities of epiphytic bacteria isolated from Padina pavonica (Peacocks tail) located on northern coast of Tunisia. Eighteen isolates were obtained in pure culture and tested for antimicrobial activities. Based on the 16S rRNA gene sequences the isolates were closely related to Proteobacteria (12 isolates; 2 Alpha- and 10 Gammaproteobacteria), Firmicutes (4 isolates) and Actinobacteria (2 isolates). The antimicrobial activity was assessed as inhibition of growth of 12 species of pathogenic bacteria (Aeromonas salmonicida, A. hydrophila, Enterobacter xiangfangensis, Enterococcus faecium, Escherichia coli, Micrococcus sp., Salmonella typhimurium, Staphylococcus aureus, Streptococcus sp., Vibrio alginoliticus, V. proteolyticus, V. vulnificus) and one pathogenic yeast (Candida albicans). Among the Firmicutes, isolate P8, which is closely related to Bacillus pumilus, displayed the largest spectrum of growth inhibition of the pathogenic bacteria tested. The results emphasize the potential use of P. pavonica associated antagonistic bacteria as producers of novel antibacterial compounds. PMID:27462308

Detection of multiple potentially pathogenic bacteria in Matang mangrove estuaries, Malaysia.

PubMed

Ghaderpour, Aziz; Mohd Nasori, Khairul Nazrin; Chew, Li Lee; Chong, Ving Ching; Thong, Kwai Lin; Chai, Lay Ching

2014-06-15

The deltaic estuarine system of the Matang Mangrove Forest Reserve of Malaysia is a site where several human settlements and brackish water aquaculture have been established. Here, we evaluated the level of fecal indicator bacteria (FIB) and the presence of potentially pathogenic bacteria in the surface water and sediments. Higher levels of FIB were detected at downstream sampling sites from the fishing village, indicating it as a possible source of anthropogenic pollution to the estuary. Enterococci levels in the estuarine sediments were higher than in the surface water, while total coliforms and E. coli in the estuarine sediments were not detected in all samples. Also, various types of potentially pathogenic bacteria, including Klebsiella pneumoniae, Serratia marcescens and Enterobacter cloacae were isolated. The results indicate that the Matang estuarine system is contaminated with various types of potential human bacterial pathogens which might pose a health risk to the public. Copyright © 2014 Elsevier Ltd. All rights reserved.

Pathogen prevalence and influence of composted dairy manure application on antimicrobial resistance profiles of commensal soil bacteria.

PubMed

Edrington, Tom S; Fox, William E; Callaway, Todd R; Anderson, Robin C; Hoffman, Dennis W; Nisbet, David J

2009-03-01

Composting manure, if done properly, should kill pathogenic bacteria such as Salmonella and Escherichia coli O157:H7, providing for an environmentally safe product. Over a 3-year period, samples of composted dairy manure, representing 11 composting operations (two to six samples per producer; 100 total samples), were screened for Salmonella and E. coli O157:H7 and were all culture negative. Nonpathogenic bacteria were cultured from these compost samples that could theoretically facilitate the spread of antimicrobial resistance from the dairy to compost application sites. Therefore, we collected soil samples (three samples per plot; 10 plots/treatment; 90 total samples) from rangeland that received either composted dairy manure (CP), commercial fertilizer (F), or no treatment (control, CON). Two collections were made appoximately 2 and 7 months following treatment application. Soil samples were cultured for Pseudomonas and Enterobacter and confirmed isolates subjected to antimicrobial susceptibility testing. Three species of Enterobacter (cloacae, 27 isolates; aeroginosa, two isolates; sakazakii, one isolate) and two species of Pseudomonas (aeruginosa, 11 isolates; putida, seven isolates) were identified. Five Enterobacter isolates were resistant to ampicillin and one isolate was resistant to spectinomycin. All Pseudomonas isolates were resistant to ampicillin, ceftiofur, florfenicol, sulphachloropyridazine, sulphadimethoxine, and trimethoprim/sulfamethoxazole and most isolates were resistant to chlortetracycline and spectinomycin. Pseudomonas isolates were resistant to an average of 8.6, 7.9, and 8 antibiotics for CON, CP, and F treatments, respectively. No treatment differences were observed in antimicrobial resistance patterns in any of the soil isolates examined. Results reported herein support the use of composted dairy manure as an environmentally friendly soil amendment.

The status of the species Enterobacter siamensisKhunthongpan et al. 2014. Request for an Opinion.

PubMed

Kämpfer, Peter; Doijad, Swapnil; Chakraborty, Trinad; Glaeser, Stefanie P

2016-01-01

In the course of a taxonomic study describing novel species of the genus Enterobacter it was found that the 16S rRNA gene sequence of the type strain of Enterobacter siamensis, obtained both directly from the authors of the publication on Enterobacter siamensis and from the Korean Collection for Type Cultures (C2361T and KCTC 23282T, respectively), was not congruent with the 16S rRNA gene sequence deposited in the GenBank database under the accession number HQ888848, which was applied for phylogenetic analysis in the species proposal. The remaining deposit in the Japanese type culture collection, NBRC 107138T, showed an identical 16S rRNA gene sequence to the other two cultures and overall, this sequence differed at 35 positions in comparison with the 1429 bp sequence published under the accession number HQ888848.Therefore, the type strain of this species cannot be included in any further scientific comparative study. It is proposed that the Judicial Commission of the International Committee on Systematics of Prokaryotes place the name Enterobacter siamensis on the list of rejected names, if a suitable replacement for the type strain is not found or a neotype strain is not proposed within two years following the publication of this Request for an Opinion.

Studies of the Acetate Kinase-Phosphotransacetylase and the Butanediol-Forming Systems in Aerobacter aerogenes

PubMed Central

Brown, T. D. K.; Pereira, C. R. S.; Størmer, F. C.

1972-01-01

Mutants of Aerobacter aerogenes devoid of acetate kinase and phosphotransacetylase activities were isolated by selection for resistance to fluoroacetate on lactate medium. The mutants were used to study the role of the acetate kinase-phosphotransacetylase system in growth on acetate and glucose. Acetate kinase-negative and phosphotransacetylase-negative mutants were unable to grow on acetate minimal medium. Their growth rates on glucose minimal medium were identical with that of the parent strain under aerobic conditions, but lower growth rates were observed in the mutant strains during anaerobic growth on glucose medium. The mutants were unable to incorporate [2-14C]-acetate rapidly while growing on glycerol. Variations in acetate kinase and phosphotransacetylase levels during growth on glucose were studied. The specific activities of the enzymes increased approximately fivefold during aerobic growth on glucose in batch culture. The enzyme levels were also studied during anaerobic growth on glucose at constant pH (pH 5.8 and 7.0). Smaller increases in specific activities were found under these conditions. The role of acetate in the induction of the diacetyl (acetoin) reductase was investigated using a mutant deficient in both acetate kinase and phosphotransacetylase. The effect of pH on the induction of this enzyme during growth on glucose under anaerobic conditions was tested. The data support the idea that free acetic acid is the inducer for the enzymes of the butanediol-forming pathway in A. aerogenes. PMID:4640502

Structure of the exopolysaccharide produced by Enterobacter amnigenus.

PubMed

Cescutti, Paola; Kallioinen, Anne; Impallomeni, Giuseppe; Toffanin, Renato; Pollesello, Piero; Leisola, Matti; Eerikäinen, Tero

2005-02-28

The bacterial species Enterobacter amnigenus was isolated from sugar beets harvested in Finland. It produced an exopolysaccharide rich in l-fucose, which gave viscous water solutions. Its primary structure was determined mainly by NMR spectroscopy and ESIMS of oligosaccharides and a polysaccharide with decreased molecular weight, obtained by Smith degradation of the O-deacetylated native polymer [carbohydrate structure: see text

Catecholamines and in vitro growth of pathogenic bacteria: enhancement of growth varies greatly among bacterial species

NASA Technical Reports Server (NTRS)

Belay, Tesfaye; Aviles, Hernan; Vance, Monique; Fountain, Kimberly; Sonnenfeld, Gerald

2003-01-01

The purpose of this study was to examine the effects of catecholamines on in vitro growth of a range of bacterial species, including anaerobes. Bacteria tested included: Porphyromonas gingivalis, Bacteriodes fragilis, Shigella boydii, Shigella sonnie, Enterobacter Sp, and Salmonella choleraesuis. The results of the current study indicated that supplementation of bacterial cultures in minimal medium with norepinephrine or epinephrine did not result in increased growth of bacteria. Positive controls involving treatment of Escherichia coli with catecholamines did result in increased growth of that bacterial species. The results of the present study extend previous observations that showed differential capability of catecholamines to enhance bacterial growth in vitro.

Confirmation of aerogenic strains of Shigella boydii 13 and further study of Shigella serotypes by DNA relatedness.

PubMed Central

Brenner, D J; Steigerwalt, A G; Wathen, H G; Gross, R J; Rowe, B

1982-01-01

Shigella boydii 13 strains are separable from other Shigella and Escherichia coli strains on the basis of DNA relatedness. From this observation, it was possible to confirm the existence of aerogenic S. boydii 13 strains. DNA relatedness studies also showed that strains of E. coli and strains representing all other serotypes of Shigella, including provisional strains, belong to the same genetic species. PMID:6752183

Antimicrobial assay and genetic screening of selected freshwater Cyanobacteria and identification of a biomolecule dihydro-2H-pyran-2-one derivative.

PubMed

Srivastava, A; Singh, V K; Patnaik, S; Tripathi, J; Singh, P; Nath, G; Asthana, R K

2017-04-01

Explorations of freshwater Cyanobacteria as antimicrobial (bacteria, fungi and methicillin-resistant Staphylococcus aureus (MRSA) strains) drug resource using bioassay, NRPS (non-ribosomal polypeptide synthetase) and PKS (polyketide synthase) genes, as well as in silico approach. We have bioassayed the extracts of Phormidium CCC727, Geitlerinema CCC728, Arthrospira CCC729, Leptolyngbya CCC732, Phormidium CCC730, Phormidium CCC731 against six pathogenic bacteria comprising Gram (+ve): S. aureus including seven clinical MRSA and Enterococcus faecalis, Gram (-ve): Escherichia coli, Salmonella Typhimurium, Klebsiella pneumoniae and Shigella boydii along with non-pathogenic Enterobacter aerogenes as well as fungal strains (Cryptococcus neoformans and Candida albicans, C. krusei, C. tropicalis and Aspergillus niger) exhibiting antimicrobial potential. The NRPS and PKS genes of the target strains were also amplified and sequenced. The putative protein structures were predicted using bioinformatics approach. PKS gene expression indicated β keto-acyl synthase as one of the important active domains in the biomolecules related to antitumour and antifungal group. The simultaneous identification of the biomolecule (dihydro-2H-pyran-2-one derivative) was also inferred spectroscopically. Freshwater Cyanobacteria are prolific producers of secondary metabolite(s) that may act as the antimicrobial drug resource in addition to their much explored marine counterpart. © 2016 The Society for Applied Microbiology.

Determination of Antibacterial and Antioxidant Potential of Some Medicinal Plants from Saurashtra Region, India

PubMed Central

Kaneria, M.; Baravalia, Y.; Vaghasiya, Y.; Chanda, S.

2009-01-01

Many plants used in Saurashtra folk medicine have been reported to exhibit high antibacterial and antioxidant activities. In the present study, some parts of five plants, Guazuma ulmifolia L., Manilkara zapota L., Melia azedarach L., Syzygium cumini L. and Wrightia tomentosa R.& S., were evaluated for their antibacterial activity, total phenol content, flavonoid content, 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity and phytochemical analysis, using successive extraction by cold percolation method with petroleum ether, ethyl acetate, methanol and water. In vitro antibacterial activity was evaluated against five bacterial strains viz. Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella typhimurium and Enterobacter aerogenes by agar well diffusion method. Among the plants screened, W. tomentosa leaf and fruit showed the best antibacterial activity. The Gram-positive bacteria were more susceptible than Gram-negative bacteria. Methanol extract of M. zapota showed the best 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity. Highest total phenol content was shown by M. zapota and S. cumini in methanol extract, while highest flavonoid content was shown by W. tomentosa stem in petroleum ether extract and ethyl acetate extract. In all the plants, cardiac glycosides and triterpenes were more as compared to other phytoconstituents. PMID:20502546

Synthesis, spectral characterization, structural investigation and antimicrobial studies of mononuclear Cu(II), Ni(II), Co(II), Zn(II) and Cd(II) complexes of a new potentially hexadentate N2O4 Schiff base ligand derived from salicylaldehyde

NASA Astrophysics Data System (ADS)

Keypour, Hassan; Shayesteh, Maryam; Rezaeivala, Majid; Chalabian, Firoozeh; Elerman, Yalcin; Buyukgungor, Orhan

2013-01-01

A new potentially hexadentate N2O4 Schiff base ligand, H2L derived from condensation reaction of an aromatic diamine and salicylaldehyde, and its metal complexes were characterized by elemental analyses, IR, UV-Vis, EI-MS, 1H and 13C NMR spectra, as well as conductance measurements. It has been originated that the Schiff base ligand with Cu(II), Ni(II), Co(II), Cd(II) and Zn(II) ions form mononuclear complexes on 1:1 (metal:ligand) stoichiometry. The conductivity data confirm the non-electrolytic nature of the complexes. Also the crystal structures of the complexes [ZnL] and [CoL] have also been determined by using X-ray crystallographic technique. The Zn(II) and Co(II) complexes show a tetrahedral configuration. Electronic absorption spectra of the Cu(II) and Ni(II) complexes suggest a square-planar geometry around the central metal ion. The synthesized compounds have antibacterial activity against the three Gram-positive bacteria: Bacillus cereus, Enterococcus faecalis and Listeria monocytogenes and also against the three Gram-negative bacteria: Salmonella paraB, Citrobacter freundii and Enterobacter aerogenes. The results showed that in some cases the antibacterial activity of complexes were more than nalidixic acid and amoxicillin as standards.

The role of bioactive substances in controlling foodborne pathogens derived from Metasequoia glyptostroboides Miki ex Hu.

PubMed

Bajpai, Vivek K; Na, Minkyun; Kang, Sun Chul

2010-07-01

In an attempt to isolate bioactive substances, ethyl acetate cone extract of Metasequoia glyptostroboides was subjected to a column chromatographic analysis that resulted in isolation of an abietane type diterpenoid, taxoquinone. Its structure was elucidated by spectroscopic means. In further, taxoquinone showed potential antibacterial effect as diameters of zones of inhibition against foodborne pathogenic bacteria such as Listeria monocytogenes ATCC 19166, Salmonella typhimurium KCTC 2515, Salmonella enteritidis KCTC 2021, Escherichia coli ATCC 8739, E. coli O157:H7 ATCC 43888, Enterobacter aerogenes KCTC2190, Staphylococcus aureus ATCC 6538 and S. aureus KCTC 1916, which were found in the range of 10.6-15.8mm. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of taxoquinone against the employed bacterial pathogens were found in the range of 62.5-250 and 125-500 microg/ml. Also the compound had strong antibacterial effect on the viable counts of the tested bacteria. Further, scanning electron microscopic study demonstrated potential detrimental effect of taxoquinone on the morphology of E. coli ATCC 8739. These findings indicate that bioactive compound taxoquinone present in M. glyptostroboides could be used as a promising antibacterial agent in food industry to inhibit the growth of certain important foodborne pathogens. 2010 Elsevier Ltd. All rights reserved.

Stereoselective synthesis, spectral and antimicrobial studies of some cyanoacetyl hydrazones of 3-alkyl-2,6-diarylpiperidin-4-ones

NASA Astrophysics Data System (ADS)

Velayutham Pillai, M.; Rajeswari, K.; Vidhyasagar, T.

2014-11-01

A series of novel cyanoacetyl hydrazones of 3-alkyl-2,6-diarylpiperidin-4-ones were synthesized stereoselectively and characterized by IR, Mass, 1H NMR, 13C NMR, 1H-1H COSY and 1H-13C COSY spectra. The stereochemistry of the synthesized compounds was established using NMR spectra. Antimicrobial screening of the synthesized compounds revealed their antibacterial and antifungal potencies. Growth inhibition of Enterobacter Aerogenes by compound 15 was found to be superior to the standard drug.

Acanthamoeba and bacteria produce antimicrobials to target their counterpart

PubMed Central

2014-01-01

Background In the microbial ecosystem, microbes compete for space and nutrients. Consequently, some have developed the ability to kill or inhibit the growth of other competing microbes by producing antimicrobial substances. As the ‘producer’ species are generally immune to these substances, their compounds act on the competing microbial species and give the producer more space and access to nutrients for growth. Many currently used antibiotics were developed by exploiting this potential of certain microbes. Findings Here, the free-living amoeba, Acanthamoeba castellanii, was investigated for its antibacterial activity against representative Gram positive and Gram negative bacteria, while bacterial isolates were tested for their anti-amoebic properties. Conditioned medium from A. castellanii showed remarkable bactericidal properties against methicillin-resistant Staphylococcus aureus (MRSA) exhibiting almost 100% kill rate, but had limited effect against Acinetobacter sp., Pseudomonas aeruginosa and vancomycin-resistant Enterococcus faecalis (VRE). Similarly, the conditioned medium of E. coli K1 and Enterobacter sp., exhibited potent anti-Acanthamoebic effects in a concentration-dependent manner. Conditioned media of Acanthamoeba, E. coli K1 and Enterobacter sp. showed no cytotoxicity in vitro when tested against human brain microvascular endothelial cells. Active molecule/s in aforementioned amoebic and two bacterial conditioned media were 5 – 10 kDa, and <5 kDa respectively. Conclusions A. castellanii conditioned medium showed potent bactericidal properties against MRSA. The active molecule(s) are heat- and pronase-resistant, and in the 5 to 10 kDa molecular mass range. Contrary to this, E. coli K1 and Enterobacter sp., conditioned medium showed anti-amoebic effects that are <5 kDa in molecular mass, suggestive of active metabolites. PMID:24479709

Cefepime vs Other Antibacterial Agents for the Treatment of Enterobacter Species Bacteremia

PubMed Central

Siedner, Mark J.; Galar, Alicia; Guzmán-Suarez, Belisa B.; Kubiak, David W.; Baghdady, Nour; Ferraro, Mary Jane; Hooper, David C.; O'Brien, Thomas F.; Marty, Francisco M.

2014-01-01

Background. Carbapenems are recommended for treatment of Enterobacter infections with AmpC phenotypes. Although isolates are typically susceptible to cefepime in vitro, there are few data supporting its clinical efficacy. Methods. We reviewed all cases of Enterobacter species bacteremia at 2 academic hospitals from 2005 to 2011. Outcomes of interest were (1) persistent bacteremia ≥1 calendar day and (2) in-hospital mortality. We fit logistic regression models, adjusting for clinical risk factors and Pitt bacteremia score and performed propensity score analyses to compare the efficacy of cefepime and carbapenems. Results. Three hundred sixty-eight patients experienced Enterobacter species bacteremia and received at least 1 antimicrobial agent, of whom 52 (14%) died during hospitalization. Median age was 59 years; 19% were neutropenic, and 22% were in an intensive care unit on the day of bacteremia. Twenty-nine (11%) patients had persistent bacteremia for ≥1 day after antibacterial initiation. None of the 36 patients who received single-agent cefepime (0%) had persistent bacteremia, as opposed to 4 of 16 (25%) of those who received single-agent carbapenem (P < .01). In multivariable models, there was no association between carbapenem use and persistent bacteremia (adjusted odds ratio [aOR], 1.52; 95% CI, .58–3.98; P = .39), and a nonsignificant lower odds ratio with cefepime use (aOR, 0.52; 95% CI, .19–1.40; P = .19). In-hospital mortality was similar for use of cefepime and carbapenems in adjusted regression models and propensity-score matched analyses. Conclusions. Cefepime has a similar efficacy as carbapenems for the treatment of Enterobacter species bacteremia. Its use should be further explored as a carbapenem-sparing agent in this clinical scenario. PMID:24647022

Effects of Cd, Pb, Zn, Cu-resistant endophytic Enterobacter sr CBSB1 and Rhodotorula sp. CBSB79 on the growth and phytoextraction of Brassica plants in multimetal contaminated soils.

PubMed

Wang, Wenfeng; Deng, Zujun; Tan, Hongming; Cao, Lixiang

2013-01-01

To survey the effects of endophytic Enterobacter sp. CBSB1 and Rhodotorula sp. CBSB79 resistant to Cd2+, Pb2+, Zn2+, and Cu2+ on the growth and phytoextraction of Brassica, the endophytes were isolated by surface- sterilized methods and characterized. The CBSB1 significantly increased 44.2% of the dry weight of Brassica napus in the multimetal contaminated soil (P < 0.05) and showed no effect or declined the dry weight of B. alboglabra, B. campestris ssp. chinensis var. cummunis, B. campestris ssp. chinensis var. utilis cv. Youqing12, B. campestris ssp. chinensis var. utilis cv. Lvbao701 plants. The dry weights of B. napus, B. campestris ssp. chinensis var. utilis, and B. alboglabra showed a significant increase when the CBSB79 was inoculated (P < 0.05). In general, inoculation with bacteria and yeast did not greatly alter the metal concentration in plant tissues. Compared to Enterobacter sp. CBSB1, the yeast Rhodotorula sp CBSB79 showed higher potentials to improve extraction efficacy of Cd, Pb, Zn, and Cu by Brassica seedlings in the field.

In vitro activity and beta-lactamase stability of a new difluoro oxacephem, 6315-S.

PubMed Central

Neu, H C; Chin, N X

1986-01-01

6315-S, a novel difluoromethyl thioacetamido oxacephem, had in vitro activity comparable to that of cefotaxime and moxalactam against Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Klebsiella oxytoca, Citrobacter diversus, Salmonella spp., and Shigella spp., inhibiting 90% at less than or equal to 0.25 microgram/ml. It inhibited piperacillin- and cefoperazone-resistant isolates in these species. 6315-S did not inhibit cefotaxime- or moxalactam-resistant Citrobacter freundii, Enterobacter aerogenes, or Enterobacter cloacae (MICs for 90% of the strains tested were greater than or equal to 16 micrograms/ml). Proteus vulgaris resistant to cefotaxime was inhibited. Pseudomonas species and Acinetobacter species were resistant (MICs greater than 64 micrograms/ml). MICs for 90% of the Staphylococcus aureus and S. epidermidis isolates were 4 micrograms/ml. 6315-S was highly active against anaerobic species of Clostridium, Fusobacterium, Bacteroides, and peptostreptococci and was superior to other agents against these organisms. 6315-S was not hydrolyzed by the major plasmid and chromosomal beta-lactamases, but it induced chromosomal beta-lactamases in Enterobacter cloacae and Pseudomonas aeruginosa. PMID:3492172

Synthesis and characterization of 3-aminoquinoline derivatives and studies of photophysicochemical behaviour and antimicrobial activities

NASA Astrophysics Data System (ADS)

Zengin, Gulay; Nafea Al Kawaz, Ali Muayad; Zengin, Huseyin; Mert, Adem; Kucuk, Bedia

2016-01-01

A series of 3-aminoquinoline derivatives were synthesized, where their chemical structures were confirmed by various analytical techniques, such as, Elemental Analysis, Nuclear Magnetic Resonance Spectroscopy (1H and 13C NMR), Liquid Chromatography-Mass-Mass Spectroscopy (LC-MS-MS), Ultraviolet-Visible Spectroscopy (UV-Vis), Fourier Transform Infrared Spectroscopy (FTIR) and Photoluminescence (PL). The quinoline ring core, typical of aminoquinolines, and a naphthalene group was combined to devise (4-alkyl-1-naphthyl)-quinolin-3-ylamide derivatives. These derivatives were designed and synthesized in light of the chemical and biological profiles of these important subunits. All the compounds were evaluated for their in vitro antibacterial and antifungal activities by the paper disc diffusion method with Gram-positive Bacillus subtilis, Bacillus megaterium and Staphylococcus aureus, Gram-negative Enterobacter aerogenes, Eschericha coli, Klebsiella pneumoniae and Pseudomonas aeruginosa and yeasts Candida albicans, Saccharomyces cerevisiae and Yarrovia lipolytica. These compounds showed antimicrobial activities against Gram-positive and Gram-negative bacteria and several yeasts, and thus their activity was not restricted to any particular type of microorganism.

Presence, distribution and molecular epidemiology of multi-drug-resistant Gram-negative bacilli from medical personnel of intensive care units in Tianjin, China, 2007-2015.

PubMed

Liu, H; Fei, C N; Zhang, Y; Liu, G W; Liu, J; Dong, J

2017-06-01

Multi-drug-resistant Gram-negative bacteria (MDRGNB) have become an important cause of nosocomial infection in intensive care units (ICUs). To investigate the molecular epidemiology of MDRGNB isolated from medical personnel (MP) and non-medical personnel (NMP) at 69 ICUs in Tianjin, China. From April 2007 to October 2015, 2636 nasal and hand swab samples from 1185 MP and 133 NMP were cultured for GNB (including MDRGNB), meticillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE). The susceptibilities of GNB to 14 antimicrobial agents were determined, and 80 MDRGNB were characterized using pulsed-field gel electrophoresis (PFGE) and dendrogram analysis. In total, 301 GNB were identified in 269 MP, including 109 MDRGNB isolates in 104 MP. Forty-two GNB were isolated from 39 NMP, which included 20 NMP with MDRGNB. Overall, 8.8% of MP were colonized with MDRGNB, which greatly exceeded colonization rates with MRSA (0.9%) and VRE (0.1%). Three pairs of Klebsiella pneumoniae and one pair of Enterobacter aerogenes were indistinguishable from each other, but the majority of isolate tests had distinct PFGE profiles. The prevalence of MDRGNB was high among ICU MP in Tianjin, and greatly exceeded that of VRE and MRSA. There was no difference in the rates of nasal carriage of MDRGNB between MP and NMP, but NMP were significantly more likely to have hand colonization with MDRGNB. PFGE profiles showed that there was only limited sharing of strains of MDR E. aerogenes and K. pneumoniae between personnel. Copyright © 2017 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Metagenomics workflow analysis of endophytic bacteria from oil palm fruits

NASA Astrophysics Data System (ADS)

Tanjung, Z. A.; Aditama, R.; Sudania, W. M.; Utomo, C.; Liwang, T.

2017-05-01

Next-Generation Sequencing (NGS) has become a powerful sequencing tool for microbial study especially to lead the establishment of the field area of metagenomics. This study described a workflow to analyze metagenomics data of a Sequence Read Archive (SRA) file under accession ERP004286 deposited by University of Sao Paulo. It was a direct sequencing data generated by 454 pyrosequencing platform originated from oil palm fruits endophytic bacteria which were cultured using oil-palm enriched medium. This workflow used SortMeRNA to split ribosomal reads sequence, Newbler (GS Assembler and GS Mapper) to assemble and map reads into genome reference, BLAST package to identify and annotate contigs sequence, and QualiMap for statistical analysis. Eight bacterial species were identified in this study. Enterobacter cloacae was the most abundant species followed by Citrobacter koseri, Seratia marcescens, Latococcus lactis subsp. lactis, Klebsiella pneumoniae, Citrobacter amalonaticus, Achromobacter xylosoxidans, and Pseudomonas sp. respectively. All of these species have been reported as endophyte bacteria in various plant species and each has potential as plant growth promoting bacteria or another application in agricultural industries.

Halotolerance and survival kinetics of lactic acid bacteria isolated from jalapeño pepper (Capsicum annuum L.) fermentation.

PubMed

González-Quijano, Génesis Karendash; Dorantes-Alvarez, Lidia; Hernández-Sánchez, Humberto; Jaramillo-Flores, María Eugenia; de Jesús Perea-Flores, María; Vera-Ponce de León, Arturo; Hernández-Rodríguez, César

2014-08-01

The microbiota associated with spontaneous fermentation of vegetables in a saline substrate may represent an important group of bacteria in the food industry. In this work, the lactic acid bacteria (LAB) Weissella cibaria, Lactobacillus plantarum, Lactobacillus paraplantarum, and Leuconostoc citreum were identified by partial 16S rRNA gene sequence analysis. In addition, entophytic bacteria such as Pantoea eucalypti, Pantoea anthophila, Enterobacter cowanii, and Enterobacter asburiae were detected, but they were irrelevant for the fermentation process and were inhibited after 12 h of fermentation when the pH decreased from 6.5 to 4.9. Moreover, 2 species of yeast were isolated and identified as Hanseniaspora pseudoguilliermondii and Kodamaea ohmeri by their partial 26S rRNA gene sequence. The growth of LAB was evaluated at different sodium chloride contents. L. citreum was the most halotolerant species followed by L. plantarum and W. cibaria with a concentration index to obtain a 50% population reduction (IC(50)) of 7.2%, 6.6%, and 5.2%, respectively. Furthermore, the growth of LAB and Escherichia coli O157:H7 was evaluated in the presence of the main phenylpropanoids from chilli peppers such as p-coumaric and ferulic acid. It was determined that LAB can grow in both acids at 4 mM, unlike E. coli O157:H7, whose growth is inhibited in the presence of these acids. © 2014 Institute of Food Technologists®

Coliform Bacteria for Bioremediation of Waste Hydrocarbons

PubMed Central

2017-01-01

Raw, domestic sewage of Kuwait City contained about 106 ml−1 colony forming units of Enterobacter hormaechei subsp. oharae (56.6%), Klebsiella spp. (36%), and Escherichia coli (7.4%), as characterized by their 16S rRNA-gene sequences. The isolated coliforms grew successfully on a mineral medium with crude oil vapor as a sole source of carbon and energy. Those strains also grew, albeit to different degrees, on individual n-alkanes with carbon chains between C9 and C36 and on the individual aromatic hydrocarbons, toluene, naphthalene, phenanthrene, and biphenyl as sole sources of carbon and energy. These results imply that coliforms, like other hydrocarbonoclastic microorganisms, oxidize hydrocarbons to the corresponding alcohols and then to aldehydes and fatty acids which are biodegraded by β-oxidation to acetyl CoA. The latter is a well-known key intermediate in cell material and energy production. E. coli cells grown in the presence of n-hexadecane (but not in its absence) exhibited typical intracellular hydrocarbon inclusions, as revealed by transmission electron microscopy. Raw sewage samples amended with crude oil, n-hexadecane, or phenanthrene lost these hydrocarbons gradually with time. Meanwhile, the numbers of total and individual coliforms, particularly Enterobacter, increased. It was concluded that coliform bacteria in domestic sewage, probably in other environmental materials too, are effective hydrocarbon-biodegrading microorganisms. PMID:29082238

Genome Sequence of the Enterobacter mori Type Strain, LMG 25706, a Pathogenic Bacterium of Morus alba L. ▿

PubMed Central

Zhu, Bo; Zhang, Guo-Qing; Lou, Miao-Miao; Tian, Wen-Xiao; Li, Bin; Zhou, Xue-Ping; Wang, Guo-Feng; Liu, He; Xie, Guan-Lin; Jin, Gu-Lei

2011-01-01

Enterobacter mori is a plant-pathogenic enterobacterium responsible for the bacterial wilt of Morus alba L. Here we present the draft genome sequence of the type strain, LMG 25706. To the best of our knowledge, this is the first genome sequence of a plant-pathogenic bacterium in the genus Enterobacter. PMID:21602328

Partial hydrolysis of dieldrin by Aerobacter aerogenes

USGS Publications Warehouse

Wedemeyer, Gary

1968-01-01

Although dieldrin (1,2,3,4,10,10-hexachloro- 6,7-epoxy-1 ,4 ,4a ,5 ,6 ,7 ,8, 8a-octahydro-1 ,4-endo, exo-5, 8-dimethanonaphthalene) metabolism by mammals (F. Korte and H. Arent, Life Sci. 4:2017, 1965) and insects (D. F. Heath and M. Vanderkar, Brit. J. Ind. Med. 21:269, 1964) has been reported, little is known about the degradation of this important pesticide by microorganisms. Korte et al. (Ann. Chem. Liebigs 656:135, 1962) and Chacko et al. (Science 154: 893, 1966) reported that a number of ubiquitous microorganisms were incapable of degrading dieldrin; however, more recently Matsumura and Boush (Science 156:959, 1967) isolated several species of Pseudomonas and Bacillus which could degrade dieldrin, from a number of soil samples having similar activity. They did not specifically attempt to identify the dieldrin metabolites formed, but they did suggest, on the basis of an identical RF value with an authentic control that 6,7-trans-dihydroxydihydroaldrin (aldrin diol) might be a major product. Work carried out concurrently in this laboratory has shown that another ubiquitous bacterium, Aerobacter aerogenes, converts dieldrin in vitro to a compound chromatographically similar to 6,7-trans-dihydroxydihydroaldrin.

Bacteria associated with Amblyomma cajennense tick eggs

PubMed Central

Machado-Ferreira, Erik; Vizzoni, Vinicius Figueiredo; Piesman, Joseph; Gazeta, Gilberto Salles; Soares, Carlos Augusto Gomes

2015-01-01

Abstract Ticks represent a large group of pathogen vectors that blood feed on a diversity of hosts. In the Americas, the Ixodidae ticks Amblyomma cajennense are responsible for severe impact on livestock and public health. In the present work, we present the isolation and molecular identification of a group of culturable bacteria associated with A. cajennense eggs from females sampled in distinct geographical sites in southeastern Brazil. Additional comparative analysis of the culturable bacteria from Anocentor nitens, Rhipicephalus sanguineus and Ixodes scapularis tick eggs were also performed. 16S rRNA gene sequence analyses identified 17 different bacterial types identified as Serratia marcescens, Stenotrophomonas maltophilia, Pseudomonas fluorescens, Enterobacter spp., Micrococcus luteus, Ochrobactrum anthropi, Bacillus cereus and Staphylococcus spp., distributed in 12 phylogroups. Staphylococcus spp., especially S. sciuri, was the most prevalent bacteria associated with A. cajennense eggs, occurring in 65% of the samples and also frequently observed infecting A. nitens eggs. S. maltophilia, S. marcescens and B. cereus occurred infecting eggs derived from specific sampling sites, but in all cases rising almost as pure cultures from infected A. cajennense eggs. The potential role of these bacterial associations is discussed and they possibly represent new targets for biological control strategies of ticks and tick borne diseases. PMID:26537602

Antibiotic resistance in bacteria isolated from vegetables with regards to the marketing stage (farm vs. supermarket).

PubMed

Schwaiger, Karin; Helmke, Katharina; Hölzel, Christina Susanne; Bauer, Johann

2011-08-15

The aim of this study was to elucidate whether and to what extent fresh produce from Germany plays a role as a carrier and reservoir of antibiotic resistant bacteria. For this purpose, 1001 vegetables (fruit, root, bulbous vegetables, salads and cereals) were collected from 13 farms and 11 supermarkets in Germany and examined bacteriologically. Phenotypic resistance of Enterobacter cloacae (n=172); Enterobacter gergoviae (n=92); Pantoea agglomerans (n=96); Pseudomonas aeruginosa (n=295); Pseudomonas putida (n=106) and Enterococcus faecalis (n=100) against up to 30 antibiotics was determined by using the microdilution method. Resistance to ß-lactams was most frequently expressed by P. agglomerans and E. gergoviae against cefaclor (41% and 29%). Relatively high resistance rates were also observed for doxycycline (23%), erythromycin (21%) and rifampicin (65%) in E. faecalis, for spectinomycin (28%) and mezlocillin (12%) in E. cloacae, as well as for streptomycin (19%) in P. putida. In P. aeruginosa, relatively low resistance rates were observed for the aminoglycosides amikacin, apramicin, gentamicin, neomycin, netilmicin and tobramycin (<4%); 11% was resistant to streptomycin. No glycopeptide-resistant enterococci were observed. Resistance rates of bacteria isolated from farm samples were higher than those of the retail markets whenever significant differences were observed. This suggests that expressing resistance is at the expense of bacterial viability, since vegetables purchased directly at the farm are probably fresher than at the supermarket, and they have not been exposed to stress factors. However, this should not keep the customer from buying directly at the farm, since the overall resistance rates were not higher than observed in bacteria from human or animal origin. Instead, peeling or washing vegetables before eating them raw is highly recommended, since it reduces not only the risk of contact with pathogens, but also that of ingesting and spreading

Clinical and molecular epidemiology of chromosome-mediated resistance to third-generation cephalosporins in Enterobacter isolates in eastern France.

PubMed

Talon, D; Bailly, P; Bertrand, X; Thouverez, M; Mulin, B

2000-07-01

To determine both the prevalence of group I beta-lactamase-related resistance and the clinical setting in which resistance to expanded-spectrum cephalosporins occurs. Isolates of Enterobacter spp. were sensitivity tested to a range of antibiotics, and selected isolates were DNA fingerprinted by pulsed-field gel electrophoresis. The medical records of all patients with positive cultures for Enterobacter spp. were reviewed to determine the effect of previous antibiotic treatment on the susceptibility profile of these organisms. The crude incidence of colonization/infection (n = 315) was 0.51 per 100 patients and 0.73 per 1000 days of hospitalization. The 4-day and 7-day Kaplan-Meier rates of colonization/infection with Enterobacter were estimated to be 7.57% (standard deviation (SD = 3.26%) and 4.16% (SD = 2.88%)), respectively. The time lag to colonization/infection with isolates producing large amounts of Bush group 1 beta-lactamase (HLBL) (27.35 +/- 27.30 days) was significantly different from that to colonization/infection with wild-type isolates (13.59 +/- 17.93 days) (P = 0.036). Ninety-six isolates (30.5%) demonstrated acquired resistance to expanded-spectrum cephalosporins: 34 isolates (10.8%) produced extended-spectrum beta-lactamase, and 62 isolates (19.7%) produced HLBL. The 89 Enterobacter isolates susceptible to third-generation cephalosporins yielded 84 major DNA patterns, and the 45 HLBL isolates yielded 38 major DNA patterns. The risk of colonization/infection with HLBL-producing Enterobacter was higher in cases of antimicrobial treatment with third-generation cephalosporins or a fluoroquinolone, and in cases of urinary tract colonization/infection. The judicious use in hospitals of both expanded-spectrum cephalosporins and other antibiotics such as fluoroquinolones is necessary to curtail the emergence of resistance in Enterobacter spp.

Genomic Epidemiology of Global Carbapenemase-Producing Enterobacter spp., 2008-2014.

PubMed

Peirano, Gisele; Matsumura, Yasufumi; Adams, Mark D; Bradford, Patricia; Motyl, Mary; Chen, Liang; Kreiswirth, Barry N; Pitout, Johann D D

2018-06-01

We performed whole-genome sequencing on 170 clinical carbapenemase-producing Enterobacter spp. isolates collected globally during 2008-2014. The most common carbapenemase was VIM, followed by New Delhi metallo-β-lactamase (NDM), Klebsiella pneumoniae carbapenemase, oxacillin 48, and IMP. The isolates were of predominantly 2 species (E. xiangfangensis and E. hormaechei subsp. steigerwaltii) and 4 global clones (sequence type [ST] 114, ST93, ST90, and ST78) with different clades within ST114 and ST90. Particular genetic structures surrounding carbapenemase genes were circulating locally in various institutions within the same or between different STs in Greece, Guatemala, Italy, Spain, Serbia, and Vietnam. We found a common NDM genetic structure (NDM-GE-U.S.), previously described on pNDM-U.S. from Klebsiella pneumoniae ATCC BAA-214, in 14 different clones obtained from 6 countries spanning 4 continents. Our study highlights the importance of surveillance programs using whole-genome sequencing in providing insight into the molecular epidemiology of carbapenemase-producing Enterobacter spp.

Antimicrobial resistant coliform bacteria in the Gomti river water and determination of their tolerance level.

PubMed

Akhter, Asma; Imran, Mohd; Akhter, Firoz

2014-01-01

The distribution of resistance to ampicillin, chloramphenicol, sulfonamides, tetracycline, and streptomycin among coliform in the Gomti river water samples was investigated. The coliform populations were isolated on Mac Conky and eosin methylene blue (EMB) agar plates supplemented with antibiotics. The incidence of resistance among the coliform population varied considerably in different drug and water sampling sites. Coliform bacteria showed lower drug resistant viable count in sampling site-III (receiving treated wastewater) as compared to more polluted site-I and site-II. Viable count of coliform population obtained on both medium was recorded higher against erythromycin from sampling site-III. Lower viable count of coliforms was recorded against tetracycline in site-II and III. Similar resistance pattern was obtained in the frequency of E. coli and Enterobacter species from all the three sampling sites. Percentage of antibiotic resistant E. coli was observed higher than Enterobacter spp among the total coliforms against all antibiotics tested without Erythromycin and penicillin in site-I and II respectively. Isolates of E. coli and Enterobacter spp. showed their tolerance level (MIC) in the range of 2-100 against the antibiotics tested. Maximum number of isolates of both genus exhibited their MICs at lower concentration range 2-5µg/ml against ciprofloxacin, tetracyclin and amoxycillin. EMB - Eosin methylene blue, IMViC tests - Indole, Methyl Red, Voges Proskauer and Citrate Utilization Tests, MIC - Minimum inhibitory concentration.

Antimicrobial resistant coliform bacteria in the Gomti river water and determination of their tolerance level

PubMed Central

Akhter, Asma; Imran, Mohd; Akhter, Firoz

2014-01-01

The distribution of resistance to ampicillin, chloramphenicol, sulfonamides, tetracycline, and streptomycin among coliform in the Gomti river water samples was investigated. The coliform populations were isolated on Mac Conky and eosin methylene blue (EMB) agar plates supplemented with antibiotics. The incidence of resistance among the coliform population varied considerably in different drug and water sampling sites. Coliform bacteria showed lower drug resistant viable count in sampling site-III (receiving treated wastewater) as compared to more polluted site-I and site-II. Viable count of coliform population obtained on both medium was recorded higher against erythromycin from sampling site-III. Lower viable count of coliforms was recorded against tetracycline in site-II and III. Similar resistance pattern was obtained in the frequency of E. coli and Enterobacter species from all the three sampling sites. Percentage of antibiotic resistant E. coli was observed higher than Enterobacter spp among the total coliforms against all antibiotics tested without Erythromycin and penicillin in site-I and II respectively. Isolates of E. coli and Enterobacter spp. showed their tolerance level (MIC) in the range of 2-100 against the antibiotics tested. Maximum number of isolates of both genus exhibited their MICs at lower concentration range 2-5µg/ml against ciprofloxacin, tetracyclin and amoxycillin. Abbreviations EMB - Eosin methylene blue, IMViC tests - Indole, Methyl Red, Voges Proskauer and Citrate Utilization Tests, MIC - Minimum inhibitory concentration. PMID:24966515

Study of antagonistic effects of Lactobacillus strains as probiotics on multi drug resistant (MDR) bacteria isolated from urinary tract infections (UTIs).

PubMed

Naderi, Atiyeh; Kasra-Kermanshahi, Roha; Gharavi, Sara; Imani Fooladi, Abbas Ali; Abdollahpour Alitappeh, Meghdad; Saffarian, Parvaneh

2014-03-01

Urinary tract infection (UTI) caused by bacteria is one of the most frequent infections in human population. Inappropriate use of antibiotics, often leads to appearance of drug resistance in bacteria. However, use of probiotic bacteria has been suggested as a partial replacement. This study was aimed to assess the antagonistic effects of Lactobacillus standard strains against bacteria isolated from UTI infections. Among 600 samples; those with ≥10,000 cfu/ml were selected as UTI positive samples. Enterococcus sp., Klebsiella pneumoniae, Enterobacter sp., and Escherichia coli were found the most prevalent UTI causative agents. All isolates were screened for multi drug resistance and subjected to the antimicrobial effects of three Lactobacillus strains by using microplate technique and the MICs amounts were determined. In order to verify the origin of antibiotic resistance of isolates, plasmid curing using ethidium bromide and acridine orange was carried out. No antagonistic activity in Lactobacilli suspension was detected against test on Enterococcus and Enterobacter strains and K. pneumoniae, which were resistant to most antibiotics. However, an inhibitory effect was observed for E. coli which were resistant to 8-9 antibiotics. In addition, L. casei was determined to be the most effective probiotic. RESULTS from replica plating suggested one of the plasmids could be related to the gene responsible for ampicillin resistance. Treatment of E. coli with probiotic suspension was not effective on inhibition of the plasmid carrying hypothetical ampicillin resistant gene. Moreover, the plasmid profiles obtained from probiotic-treated isolates were identical to untreated isolates.

Occurrence of yeasts, enterococci and other enteric bacteria in subgingival biofilm of HIV-positive patients with chronic gingivitis and necrotizing periodontitis

PubMed Central

Gaetti-Jardim Júnior, Elerson; Nakano, Viviane; Wahasugui, Thais C.; Cabral, Fátima C.; Gamba, Rosa; Avila-Campos, Mario Julio

2008-01-01

The purpose of this study was to determine the prevalence of enteric bacteria and yeasts in biofilm of 80 HIV-positive patients with plaque-associated gingivitis or necrotizing periodontitis. Patients were subjected to extra, intra oral and radiographic examinations. The oral hygiene, bleeding on probing, gingival conditions, and attachment loss were evaluated. Clinical specimens were collected from gingival crevices or periodontal pockets, transferred to VMGA III, diluted and transferred to Sabouraud Dextrose agar with 100 μg/ml of chloramphenicol, peptone water, EVA broth, EMB agar, SS agar, Bile esculin agar and Brilliant green agar. Isolation of yeasts was carried out at room temperature, for 3-7 days; and for the isolation of enteric microorganisms plates were incubated at 37°C, for 24-48 h. The yeasts identification was performed according to the carbon and nitrogen assimilation, fermentation of carbohydrates and germ tube formation. Bacteria were identified according to their colonial and cellular morphologies and biochemical tests. Yeasts were identified as Candida albicans and its occurrence was more common in patients with CD4+ below 200/mm3 and was affected by the extension of periodontal involvement (P = 0.0345). Enteric bacteria recovered from clinical specimens were identified as Enterobacter sakazakii, Enterobacter cloacae, Serratia liquefaciens, Klebsiella oxytoca and Enterococcus sp. Enterobacteriaceae and enterococci were detected in 32.5% of clinical samples from patients with necrotizing periodontitis. In conclusion, non-oral pathogenic bacteria and C. albicans were more prevalent in periodontal sites of HIV-positive patients with necrotizing periodontitis and chronic gingivitis. PMID:24031212

In vitro susceptibility and resistance phenotypes in contemporary Enterobacter isolates in a university hospital in Crete, Greece.

PubMed

Maraki, Sofia; Vardakas, Konstantinos Z; Samonis, George; Perdikis, Dimitrios; Mavromanolaki, Viktoria Eirini; Kofteridis, Diamantis P; Falagas, Matthew E

2017-06-01

To study the evolution in the susceptibility of Enterobacter spp. in Crete, Greece from 2010 to 2015. Non-duplicate isolates were studied using automated systems. Phenotypic confirmatory tests were applied. A total of 939 Enterobacter isolates were included. Colistin was the most active antibiotic (97.9%) followed by imipenem (96.1%), gentamicin (95.7%), tigecycline (91.8%), cefepime (89.4%), chloramphenicol (85.8%), fosfomycin (85.5%), trimethoprim/sulfamethoxazole (83.3%) and piperacillin/tazobactam (73.3%). Antibiotic resistance did not increase during the study period for most antibiotics. Lower susceptibility was observed among multidrug-resistant strains and carbapenem-nonsusceptible isolates. AmpC was the most common resistant mechanism (21%); carbapenemases (3.7%) and aminoglycoside-modifying enzymes (6.5%) were also detected. A significant proportion of Enterobacter spp. was resistant to several antibiotics, most notably β-lactams.

Integrated evaluation of aerogenic pollution by air-transported heavy metals (Pb, Cd, Ni, Zn, Mn and Cu) in the analysis of the main deposit media.

PubMed

Baltrėnaitė, Edita; Baltrėnas, Pranas; Lietuvninkas, Arvydas; Serevičienė, Vaida; Zuokaitė, Eglė

2014-01-01

The composition of the ambient air is constantly changing; therefore, the monitoring of ambient air quality to detect the changes caused by aerogenic pollutants makes the essential part of general environmental monitoring. To achieve more effective improvement of the ambient air quality, the Directive 2008/50/EC on 'Ambient Air Quality and Cleaner Air for Europe' was adopted by the European Parliament and the European Council. It informed the public and enterprises about a negative effect of pollution on humans, animals and plants, as well as about the need for monitoring aerogenic pollutants not only at the continuous monitoring stations but also by using indicator methods, i.e. by analysing natural deposit media. The problem of determining the relationship between the accumulation level of pollutants by a deposit medium and the level of air pollution and its risks is constantly growing in importance. The paper presents a comprehensive analysis of the response of the main four deposit media, i.e. snow cover, soil, pine bark and epigeic mosses, to the long-term pollution by aerogenic pollutants which can be observed in the area of oil refinery influence. Based on the quantitative expressions of the amounts of the accumulated pollutants in the deposit media, the territory of the oil refinery investigated in this paper has been referred to the areas of mild or moderate pollution.

Improvement of cadmium phytoremediation by Centella asiatica L. after soil inoculation with cadmium-resistant Enterobacter sp. FM-1.

PubMed

Li, Yi; Liu, Kehui; Wang, Yang; Zhou, Zhenming; Chen, Chaoshu; Ye, Panhua; Yu, Fangming

2018-07-01

This study examined the potential of a cadmium-resistant Enterobacter sp. FM-1 to promote plant growth and assist in cadmium accumulation in both mine-type C. asiatica L. and non-mine type C. asiatica L. tissues in highly cadmium-polluted soils. The results indicated that Enterobacter sp. FM-1 significantly promoted growth and alleviated metal toxicity in both types of C. asiatica L. Meanwhile, inoculation with Enterobacter sp. FM-1 in contaminated soil can increased cadmium bioavailability in soil. Furthermore, it will increase plant uptake and the accumulation of cadmium in C. asiatica L. leaves, stems and roots compared to that in an uninoculated plant. However, mine-type C. asiatica L. had better cadmium tolerance than the non mine-type C. asiatica L. Because of its native metal-tolerant ability, which could easily grow and proliferate, and had a better performance under cadmium-contamination conditions. Additionally, inoculation with Enterobacter sp. FM-1 significantly enhanced the bioaccumulation factor (BAF) and the translocation factor (TF) values in both types of C. asiatica L. even under high cadmium concentration soil condition. Hence, based on higher BAF and TF values and strong cadmium accumulation in the leaves and stems, we concluded that inoculation with Enterobacter sp. FM-1 is potentially useful for the phytoremediation of cadmium-contaminated sites by Centella asiatica L. Copyright © 2018 Elsevier Ltd. All rights reserved.

Synergistic action between sisomicin and mezlocillin against gram-negative bacteria and Staphylococcus aureus.

PubMed

Soares, L A; Trabulsi, L R

1979-01-01

The combined effect of sisomicin and 6-[(R)-2-[3-methylsulfonyl-2-oxo-imidazolidine-1-carboxamido]-2-phenyl-acetamido-a1-penicillanic acid sodium salt (mezlocillin, Baypen) was studied against 50 bacterial strains, including Pseudomonas aeruginosa, Proteus spp. Klebsiella-Enterobacter, E. coli and Staphylococcus aureus. No antagonism or indifference was detected with the strains studied. Both antibiotics were synergistic against 62% of the strains, and partially synergistic against 38%. Out of the bacteria studied, Staphylococcus aureus was the most susceptible to the combined action of sisomicin and mezlocillin.

Microarray-based Comparative Genomic Indexing of the Cronobacter genus (Enterobacter sakazakii)

USDA-ARS?s Scientific Manuscript database

Cronobacter is a recently defined genus synonymous with Enterobacter sakazakii. This new genus currently comprises 6 genomospecies. To extend our understanding of the genetic relationship between Cronobacter sakazakii BAA-894 and the other species of this genus, microarray-based comparative genomi...

Enterobacter sp. LU1 as a novel succinic acid producer - co-utilization of glycerol and lactose.

PubMed

Podleśny, Marcin; Jarocki, Piotr; Wyrostek, Jakub; Czernecki, Tomasz; Kucharska, Jagoda; Nowak, Anna; Targoński, Zdzisław

2017-03-01

Succinic acid is an important C4-building chemical platform for many applications. A novel succinic acid-producing bacterial strain was isolated from goat rumen. Phylogenetic analysis based on the 16S rRNA sequence and physiological analysis indicated that the strain belongs to the genus Enterobacter. This is the first report of a wild bacterial strain from the genus Enterobacter that is capable of efficient succinic acid production. Co-fermentation of glycerol and lactose significantly improved glycerol utilization under anaerobic conditions, debottlenecking the utilization pathway of this valuable biodiesel waste product. Succinic acid production reached 35 g l -1 when Enterobacter sp. LU1 was cultured in medium containing 50 g l -1 of glycerol and 25 g l -1 of lactose as carbon sources. © 2016 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Aerobic and heterotrophic nitrogen removal by Enterobacter cloacae CF-S27 with efficient utilization of hydroxylamine.

PubMed

Padhi, Soumesh Kumar; Tripathy, Swetaleena; Mohanty, Sriprakash; Maiti, Nikhil Kumar

2017-05-01

Heterotrophic bacterium, Enterobacter cloacae CF-S27 exhibited simultaneous nitrification and aerobic denitrification in presence of high concentration of hydroxylamine. With the initial nitrogen concentration of 100mgL -1 h -1 , ammonium, nitrate and nitrite removal efficiencies were 81%, 99.9% and 92.8%, while the corresponding maximum removal rates reached as high as 11.6, 15.1 and 11.2mgL -1 h -1 respectively. Quantitative amplification by real time PCR and enzyme assay demonstrated that hydroxylamine reductase gene (hao) is actively involved in hetrotrophic nitrification and aerobic denitrification process of Enterobacter cloacae CF-S27. PCR primers were designed targeting amplification of hao gene from diversified environmental soil DNA. The strain Enterobacter cloacae CF-S27 significantly maintained the undetectable amount of dissolved nitrogen throughout 60days of zero water exchange fish culture experiment in domestic wastewater. Copyright © 2017 Elsevier Ltd. All rights reserved.

Clinical characteristics and outcomes of spontaneous bacterial peritonitis caused by Enterobacter species versus Escherichia coli: a matched case-control study.

PubMed

Bae, Seongman; Kim, Taeeun; Kim, Min-Chul; Chong, Yong Pil; Kim, Sung-Han; Sung, Heungsup; Lim, Young-Suk; Lee, Sang-Oh; Kim, Mi-Na; Kim, Yang Soo; Woo, Jun Hee; Choi, Sang-Ho

2016-06-07

Enterobacter species are important nosocomial pathogens, and there is growing concern about their ability to develop resistance during antimicrobial therapy. However, few data are available on the clinical characteristics and outcomes of Enterobacter spontaneous bacterial peritonitis (SBP). We retrospectively identified all patients with SBP caused by Enterobacter species admitted to a tertiary care hospital between January 1997 and December 2013. Each case was age- and sex-matched with four patients with Escherichia coli SBP. A total of 32 cases with Enterobacter SBP and 128 controls with E. coli SBP were included. Twenty-one (65.6 %) cases and 111 (86.7 %) controls had Child-Pugh class C (P = 0.006). Cases were significantly more likely to have hepatocellular carcinoma (65.6 % vs. 37.5 %, P = 0.004) and upper gastrointestinal bleeding (28.1 % vs. 9.4 %, P = 0.005). The initial response to empirical therapy (81.3 % vs. 81.2 %, P = 0.995) and the 30-day mortality (37.5 % vs. 28.9 %, P = 0.35) were not significantly different between the groups. Drug resistance emerged in one case and in no controls (4.3 % [1/23] vs. 0 % [0/98], P = 0.19). Compared with E. coli SBP, patients with Enterobacter SBP more frequently had hepatocellular carcinoma and upper gastrointestinal bleeding, yet clinical outcomes were comparable. Development of resistance during third-generation cephalosporin therapy was infrequent in patients with Enterobacter SBP.

Meningoencephalitis and Compartmentalization of the Cerebral Ventricles Caused by Enterobacter sakazakii

PubMed Central

Kleiman, Martin B.; Allen, Stephen D.; Neal, Patricia; Reynolds, Janet

1981-01-01

A necrotizing meningoencephalitis complicated by ventricular compartmentalization and abscess formation caused by Enterobacter sakazakii in a previously healthy 5-week-old female is described. A detailed description of the isolate is presented. This communication firmly establishes the pathogenicity of E. sakazakii. PMID:7287892

Genome Survey and Characterization of Endophytic Bacteria Exhibiting a Beneficial Effect on Growth and Development of Poplar Trees ▿ †

PubMed Central

Taghavi, Safiyh; Garafola, Craig; Monchy, Sébastien; Newman, Lee; Hoffman, Adam; Weyens, Nele; Barac, Tanja; Vangronsveld, Jaco; van der Lelie, Daniel

2009-01-01

The association of endophytic bacteria with their plant hosts has a beneficial effect for many different plant species. Our goal is to identify endophytic bacteria that improve the biomass production and the carbon sequestration potential of poplar trees (Populus spp.) when grown in marginal soil and to gain an insight in the mechanisms underlying plant growth promotion. Members of the Gammaproteobacteria dominated a collection of 78 bacterial endophytes isolated from poplar and willow trees. As representatives for the dominant genera of endophytic gammaproteobacteria, we selected Enterobacter sp. strain 638, Stenotrophomonas maltophilia R551-3, Pseudomonas putida W619, and Serratia proteamaculans 568 for genome sequencing and analysis of their plant growth-promoting effects, including root development. Derivatives of these endophytes, labeled with gfp, were also used to study the colonization of their poplar hosts. In greenhouse studies, poplar cuttings (Populus deltoides × Populus nigra DN-34) inoculated with Enterobacter sp. strain 638 repeatedly showed the highest increase in biomass production compared to cuttings of noninoculated control plants. Sequence data combined with the analysis of their metabolic properties resulted in the identification of many putative mechanisms, including carbon source utilization, that help these endophytes to thrive within a plant environment and to potentially affect the growth and development of their plant hosts. Understanding the interactions between endophytic bacteria and their host plants should ultimately result in the design of strategies for improved poplar biomass production on marginal soils as a feedstock for biofuels. PMID:19060168

Antibacterial and antifungal activities from Siamese crocodile blood.

PubMed

Leelawongtawon, Ratree; Siruntawineti, Jindawan; Chaeychomsri, Win; Sattaponpan, Chisanucha

2010-12-01

To evaluate the in vitro antimicrobial activity of the Siamese crocodile blood against bacteria and fungi. Thirty Siamese crocodile blood samples including freeze dried whole blood (FDWB), fresh serum (FS), and freeze dried serum (FDS) were evaluated for antimicrobial susceptibility and MIC values against ATCC-registered strains of nine bacterial species and two fungal species and one fungus isolated from a clinical specimen, by using the standard broth microdilution method and a modified resazurin microtiter plate assay. The result showed that FS (80 mg/ml) and FDS (100 mg/ml) inhibited Gram negative bacteria including Enterobacter aerogenes ATCC 13048, Escherichia coli ATCC 25922, Klebsiella pneumoniae ATCC 27736, Salmonella typhimurium ATCC 13311 and Pseudomonas aeruginosa ATCC 27853 with the susceptibility rate at 23.30%, 10.00%, 40.00%, 70.00%, and 86.67%, respectively for FS, and 30.00%, 10.00%, 43.33%, 76.67% and 90.00%, respectively for FDS. The MIC and MBC were in the range of 12.50-100.00 mg/ml and 25.00-100.00 mg/m1 respectively. FS and FDS also inhibited Cryptococcus neoformans 250309 and Aspergillus niger with the susceptibility rate at 90.00% and 80.00%, respectively for FS and 100.00% and 83.33%, respectively for FDS. The MIC was in the range of 25.00-100.00 mg/ml. However, FS and FDS did not inhibit Gram positive bacteria and did not kill fungi. FDWB (100 mg/ml) could neither inhibit bacteria nor fungi. FS and FDS from Siamese crocodile exhibited potential antibacterial and antifungal activities.

Kinetics of biological decolorisation of anthraquinone based Reactive Blue 19 using an isolated strain of Enterobacter sp.F NCIM 5545.

PubMed

Holkar, Chandrakant R; Pandit, Aniruddha B; Pinjari, Dipak V

2014-12-01

In the present study, an attempt was made to evaluate the bacterial decolorisation of Reactive Blue 19 by an Enterobacter sp.F which was isolated from a mixed culture from anaerobic digester for biogas production. Phenotypic characterization and phylogenetic analysis based on DNA sequencing comparisons indicate that Enterobacter sp.F was 99.7% similar to Enterobacter cloacae ATCC13047. The kinetics of Reactive Blue 19 dye decolorisation by bacterium had been estimated. Effects of substrate concentration, oxygen, temperature, pH, glucose and glucose to microbe weight ratio on the rate of decolorisation were investigated to understand key factor that determines the performance of dye decolorisation. The maximum decolorisation efficiency of Reactive Blue 19 was 90% over period of 24 h for optimized parameter. To the best of our knowledge, this research study is the report where Enterobacter sp.F has been reported with about 90% decolorizing ability against anthraquinone based Reactive Blue 19 dye. Copyright © 2014 Elsevier Ltd. All rights reserved.

Impact of glycerol and nitrogen concentration on Enterobacter A47 growth and exopolysaccharide production.

PubMed

Torres, Cristiana A V; Marques, Rodolfo; Ferreira, Ana R V; Antunes, Sílvia; Grandfils, Christian; Freitas, Filomena; Reis, Maria A M

2014-11-01

Enterobacter A47 produces a fucose-containing exopolysaccharide (EPS) by cultivation in mineral medium supplemented with glycerol. EPS synthesis by Enterobacter A47 was shown to be influenced by both the initial glycerol and nitrogen concentrations and by the nutrients' feeding rate during the fed-batch phase. Initial nitrogen concentrations above 1.05g/L were detrimental for EPS synthesis: the productivity was reduced to 0.35-0.62g/Ld (compared to 1.89-2.04g/Ld under lower nitrogen concentrations) and the polymer had lower fucose content (14-17%mol, compared to 36-38%mol under lower nitrogen concentrations). On the other hand, EPS productivity was improved to 5.66g/Ld by increasing the glycerol and nitrogen feeding rates during the fed-batch phase. However, the EPS thus obtained had lower fucose (26%mol) and higher galactose (34%mol) contents, as well as lower average molecular weight (7.2×10(5)). The ability of Enterobacter A47 to synthesize EPS with different physico-chemical characteristics may be useful for the generation of biopolymers with distinct functional properties suitable for different applications. Copyright © 2014 Elsevier B.V. All rights reserved.

Phylogenetic diversity of carbohydrate degrading culturable bacteria from Mandovi and Zuari estuaries, Goa, west coast of India

NASA Astrophysics Data System (ADS)

Khandeparker, Rakhee; Verma, Preeti; Meena, Ram M.; Deobagkar, Deepti D.

2011-12-01

Coastal and estuarine waters are highly productive and dynamic ecosystems. The complex carbohydrate composition of the ecosystem would lead to colonisation of microbial communities with abilities to produce an array of complex carbohydrate degrading enzymes. We have examined the abundance and phylogenetic diversity of culturable bacteria with abilities to produce complex carbohydrate degrading enzymes in the Mondovi and Zuari eustauri. It was interesting to note that 65% of isolated bacteria could produce complex carbohydrate degrading enzymes. A majority of these bacteria belonged to Bacillus genera followed by Vibrio, Marinobacter, Exiquinobacterium, Alteromonas, Enterobacter and Aeromonas. Most abundant bacterial genus to degrade hemicellulose and cellulose were Bacillus and Vibrio respectively. Most abundant bacterial genus to degrade hemicellulose and cellulose were Bacillus and Vibrio respectively. It was seen that 46% of Bacillus had ability to degrade both the substrate while only 14% of Vibrio had bifunctionality.

Global transcriptome response to ionic liquid by a tropical rain forest soil bacterium, Enterobacter lignolyticus.

PubMed

Khudyakov, Jane I; D'haeseleer, Patrik; Borglin, Sharon E; Deangelis, Kristen M; Woo, Hannah; Lindquist, Erika A; Hazen, Terry C; Simmons, Blake A; Thelen, Michael P

2012-08-07

To process plant-based renewable biofuels, pretreatment of plant feedstock with ionic liquids has significant advantages over current methods for deconstruction of lignocellulosic feedstocks. However, ionic liquids are often toxic to the microorganisms used subsequently for biomass saccharification and fermentation. We previously isolated Enterobacter lignolyticus strain SCF1, a lignocellulolytic bacterium from tropical rain forest soil, and report here that it can grow in the presence of 0.5 M 1-ethyl-3-methylimidazolium chloride, a commonly used ionic liquid. We investigated molecular mechanisms of SCF1 ionic liquid tolerance using a combination of phenotypic growth assays, phospholipid fatty acid analysis, and RNA sequencing technologies. Potential modes of resistance to 1-ethyl-3-methylimidazolium chloride include an increase in cyclopropane fatty acids in the cell membrane, scavenging of compatible solutes, up-regulation of osmoprotectant transporters and drug efflux pumps, and down-regulation of membrane porins. These findings represent an important first step in understanding mechanisms of ionic liquid resistance in bacteria and provide a basis for engineering microbial tolerance.

Structural differences in gut bacteria communities in developmental stages of natural populations of Lutzomyia evansi from Colombia's Caribbean coast.

PubMed

Vivero, Rafael José; Jaramillo, Natalia Gil; Cadavid-Restrepo, Gloria; Soto, Sandra I Uribe; Herrera, Claudia Ximena Moreno

2016-09-13

Lutzomyia evansi, a phlebotomine insect endemic to Colombia's Caribbean coast, is considered to be the main vector of visceral and cutaneous leishmaniasis in the region. Although insects of this species can harbor pathogenic and non-pathogenic microorganisms in their intestinal microbiota, there is little information available about the diversity of gut bacteria present in Lutzomyia evansi. In this study, conventional microbiological methods and molecular tools were used to assess the composition of bacterial communities associated with Lutzomyia evansi guts in immature and adult stages of natural populations from the department of Sucre (Caribbean coast of Colombia). Sand flies were collected from two locations (peri-urban and jungle biotype) in the Department of Sucre (Caribbean coast of Colombia). A total of 752 Lutzomyia evansi intestines were dissected. In this study, 125 bacterial strains were isolated from different culture media (LB Agar, MacConkey Agar). Different methods were used for bacterial identification, including ribosomal intergenic spacer analysis (RISA) and analysis of the 16S rRNA and gyrB gene sequences. The genetic profiles of the bacterial populations were generated and temporal temperature gradient gel electrophoresis (TTGE) was used to compare them with total gut DNA. We also used PCR and DNA sequence analysis to determine the presence of Wolbachia endosymbiont bacteria and Leishmania parasites. The culture-dependent technique showed that the dominant intestinal bacteria isolated belong to Acinetobacter, Enterobacter, Pseudomonas, Ochrobactrum, Shinella and Paenibacillus in the larval stage; Lysobacter, Microbacterium, Streptomyces, Bacillus and Rummeliibacillus in the pupal stage; and Staphylococcus, Streptomyces, Brevibacterium, Acinetobacter, Enterobacter and Pantoea in the adult stage. Statistical analysis revealed significant differences between the fingerprint patterns of the PCR-TTGE bands in bacterial communities from immature and

Multiresistant Enterobacter cloacae outbreak in an intensive care unit associated with therapeutic beds

PubMed Central

van der Mee-Marquet, Nathalie; Girard, Sophie; Lagarrigue, François; Leroux, Isabelle; Voyer, Isabelle; Bloc, Daniel; Besnier, Jean-Marc; Quentin, Roland

2006-01-01

We report a multiresistant Enterobacter cloacae outbreak in an intensive care unit, associated with mattresses and with antibacterial-treated and vapour-permeable polyurethane synthetic mattress covers of therapeutic beds. PMID:16542475

Method for Phenotypic Detection of Extended-Spectrum Beta-Lactamases in Enterobacter Species in the Routine Clinical Setting ▿

PubMed Central

Stuart, James Cohen; Diederen, Bram; al Naiemi, Nashwan; Fluit, Ad; Arents, Niek; Thijsen, Steven; Vlaminckx, Bart; Mouton, Johan W.; Leverstein-van Hall, Maurine

2011-01-01

In 271 Enterobacter blood culture isolates from 12 hospitals, extended-spectrum beta-lactamase (ESBL) prevalence varied between 0% and 30% per hospital. High prevalence was associated with dissemination, indicating the potential relevance of infection control measures. Screening with cefepime or Vitek 2, followed by a cefepime/cefepime-clavulanate Etest, was an accurate strategy for ESBL detection in Enterobacter isolates (positive predictive value, 100%; negative predictive value, 99%). PMID:21562100

Isolation and characterization of a glyphosate-degrading rhizosphere strain, Enterobacter cloacae K7.

PubMed

Kryuchkova, Yelena V; Burygin, Gennady L; Gogoleva, Natalia E; Gogolev, Yuri V; Chernyshova, Marina P; Makarov, Oleg E; Fedorov, Evgenii E; Turkovskaya, Olga V

2014-01-20

Plant-growth-promoting rhizobacteria exert beneficial effects on plants through their capacity for nitrogen fixation, phytohormone production, phosphate solubilization, and improvement of the water and mineral status of plants. We suggested that these bacteria may also have the potential to express degradative activity toward glyphosate, a commonly used organophosphorus herbicide. In this study, 10 strains resistant to a 10 mM concentration of glyphosate were isolated from the rhizoplane of various plants. Five of these strains--Alcaligenes sp. K1, Comamonas sp. K4, Azomonas sp. K5, Pseudomonas sp. K3, and Enterobacter cloacae K7--possessed a number of associative traits, including fixation of atmospheric nitrogen, solubilization of phosphates, and synthesis of the phytohormone indole-3-acetic acid. One strain, E. cloacae K7, could utilize glyphosate as a source of P. Gas-liquid chromatography showed that E. cloacae growth correlated with a decline in herbicide content in the culture medium (40% of the initial 5mM content), with no glyphosate accumulating inside the cells. Thin-layer chromatography analysis of the intermediate metabolites of glyphosate degradation found that E. cloacae K7 had a C-P lyase activity and degraded glyphosate to give sarcosine, which was then oxidized to glycine. In addition, strain K7 colonized the roots of common sunflower (Helianthus annuus L.) and sugar sorghum (Sorghum saccharatum Pers.), promoting the growth and development of sunflower seedlings. Our findings extend current knowledge of glyphosate-degrading rhizosphere bacteria and may be useful for developing a biotechnology for the cleanup and restoration of glyphosate-polluted soils. Copyright © 2013 Elsevier GmbH. All rights reserved.

Determination of histamine in milkfish stick implicated in food-borne poisoning.

PubMed

Lee, Yi-Chen; Kung, Hsien-Feng; Wu, Chien-Hui; Hsu, Hui-Mei; Chen, Hwi-Chang; Huang, Tzou-Chi; Tsai, Yung-Hsiang

2016-01-01

An incident of food-borne poisoning causing illness in 37 victims due to ingestion of fried fish sticks occurred in September 2014, in Tainan city, southern Taiwan. Leftovers of the victims' fried fish sticks and 16 other raw fish stick samples from retail stores were collected and tested to determine the occurrence of histamine and histamine-forming bacteria. Two suspected fried fish samples contained 86.6 mg/100 g and 235.0 mg/100 g histamine; levels that are greater than the potential hazard action level (50 mg/100 g) in most illness cases. Given the allergy-like symptoms of the victims and the high histamine content in the suspected fried fish samples, this food-borne poisoning was strongly suspected to be caused by histamine intoxication. Moreover, the fish species of suspected samples was identified as milkfish (Chanos chanos), using polymerase chain reaction direct sequence analysis. In addition, four of the 16 commercial raw milkfish stick samples (25%) had histamine levels greater than the US Food & Drug Administration guideline of 5.0 mg/100 g for scombroid fish and/or products. Ten histamine-producing bacterial strains, capable of producing 373-1261 ppm of histamine in trypticase soy broth supplemented with 1.0% L-histidine, were identified as Enterobacter aerogenes (4 strains), Enterobacter cloacae (1 strain), Morganella morganii (2 strains), Serratia marcescens (1 strain), Hafnia alvei (1 strain), and Raoultella orithinolytica (1 strain), by 16S ribosomal DNA sequencing with polymerase chain reaction amplification. Copyright © 2015. Published by Elsevier B.V.

Evidence supporting dissimilatory and assimilatory lignin degradation in Enterobacter lignolyticus SCF1

PubMed Central

DeAngelis, Kristen M.; Sharma, Deepak; Varney, Rebecca; Simmons, Blake; Isern, Nancy G.; Markilllie, Lye Meng; Nicora, Carrie; Norbeck, Angela D.; Taylor, Ronald C.; Aldrich, Joshua T.; Robinson, Errol W.

2013-01-01

Lignocellulosic biofuels are promising as sustainable alternative fuels, but lignin inhibits access of enzymes to cellulose, and by-products of lignin degradation can be toxic to cells. The fast growth, high efficiency and specificity of enzymes employed in the anaerobic litter deconstruction carried out by tropical soil bacteria make these organisms useful templates for improving biofuel production. The facultative anaerobe Enterobacter lignolyticus SCF1 was initially cultivated from Cloud Forest soils in the Luquillo Experimental Forest in Puerto Rico, based on anaerobic growth on lignin as sole carbon source. The source of the isolate was tropical forest soils that decompose litter rapidly with low and fluctuating redox potentials, where bacteria using oxygen-independent enzymes likely play an important role in decomposition. We have used transcriptomics and proteomics to examine the observed increased growth of SCF1 grown on media amended with lignin compared to unamended growth. Proteomics suggested accelerated xylose uptake and metabolism under lignin-amended growth, with up-regulation of proteins involved in lignin degradation via the 4-hydroxyphenylacetate degradation pathway, catalase/peroxidase enzymes, and the glutathione biosynthesis and glutathione S-transferase (GST) proteins. We also observed increased production of NADH-quinone oxidoreductase, other electron transport chain proteins, and ATP synthase and ATP-binding cassette (ABC) transporters. This suggested the use of lignin as terminal electron acceptor. We detected significant lignin degradation over time by absorbance, and also used metabolomics to demonstrate moderately significant decreased xylose concentrations as well as increased metabolic products acetate and formate in stationary phase in lignin-amended compared to unamended growth conditions. Our data show the advantages of a multi-omics approach toward providing insights as to how lignin may be used in nature by microorganisms coping

Evidence supporting dissimilatory and assimilatory lignin degradation in Enterobacter lignolyticus SCF1.

PubMed

Deangelis, Kristen M; Sharma, Deepak; Varney, Rebecca; Simmons, Blake; Isern, Nancy G; Markilllie, Lye Meng; Nicora, Carrie; Norbeck, Angela D; Taylor, Ronald C; Aldrich, Joshua T; Robinson, Errol W

2013-01-01

Lignocellulosic biofuels are promising as sustainable alternative fuels, but lignin inhibits access of enzymes to cellulose, and by-products of lignin degradation can be toxic to cells. The fast growth, high efficiency and specificity of enzymes employed in the anaerobic litter deconstruction carried out by tropical soil bacteria make these organisms useful templates for improving biofuel production. The facultative anaerobe Enterobacter lignolyticus SCF1 was initially cultivated from Cloud Forest soils in the Luquillo Experimental Forest in Puerto Rico, based on anaerobic growth on lignin as sole carbon source. The source of the isolate was tropical forest soils that decompose litter rapidly with low and fluctuating redox potentials, where bacteria using oxygen-independent enzymes likely play an important role in decomposition. We have used transcriptomics and proteomics to examine the observed increased growth of SCF1 grown on media amended with lignin compared to unamended growth. Proteomics suggested accelerated xylose uptake and metabolism under lignin-amended growth, with up-regulation of proteins involved in lignin degradation via the 4-hydroxyphenylacetate degradation pathway, catalase/peroxidase enzymes, and the glutathione biosynthesis and glutathione S-transferase (GST) proteins. We also observed increased production of NADH-quinone oxidoreductase, other electron transport chain proteins, and ATP synthase and ATP-binding cassette (ABC) transporters. This suggested the use of lignin as terminal electron acceptor. We detected significant lignin degradation over time by absorbance, and also used metabolomics to demonstrate moderately significant decreased xylose concentrations as well as increased metabolic products acetate and formate in stationary phase in lignin-amended compared to unamended growth conditions. Our data show the advantages of a multi-omics approach toward providing insights as to how lignin may be used in nature by microorganisms coping

In vitro effects of inulin and soya bean oligosaccharide on skatole production and the intestinal microbiota in broilers.

PubMed

Liu, H Y; Hou, R; Yang, G Q; Zhao, F; Dong, W G

2018-06-01

The experiment was conducted to investigate the in vitro effects of inulin and soya bean oligosaccharide (SBO) on the metabolism of L-tryptophan (L-try) to skatole production, and the intestinal microbiota in broilers. Treatments were as follows: caecal microbiota control (Cc), Cc + inulin, Cc + SBO, rectal microbiota control (Rc), Rc + inulin and Rc + SBO. Microbial suspensions were anaerobically incubated at 38°C for 24 hr. The results showed that concentrations of skatole and acetic acid were significantly lower in caecal microbiota fermentation broth (MFB) than those in rectal MFB (p < .05). Addition of inulin or SBO significantly decreased the concentrations of indole and skatole and rate of L-try degradation (p < .05). Inulin groups had lower indole than SBO groups (p < .05). PCR-DGGE analysis revealed that addition of inulin or SBO decreased the microbiota richness (p < .05), but no significant differences in Shannon index (p > .05). Four distinct bands were detected in inulin and SBO groups, which were related to two of Bacteroides, one of Firmicutes and Bifidobacteria. Six bands were detected only in control groups, which represented uncultured Rikenellaceae, Roseburia, Escherichia/Shigella dysenteriae, Bacteroides uniformis (T), Parabacteroides distasonis and Enterobacter aerogenes. Populations of Lactobacilli, Bifidobacteria and total bacteria in inulin groups were higher than those in control groups (p < .05). For SBO groups, only population of total bacteria increased (p < .05). However, there were no significant differences in Escherichia coli population among treatments (p > .05). These results suggest that reduced concentrations of skatole and indole in the presence of inulin and SBO may be caused by decrease in L-try degradation rate, which were caused by change in microbial ecosystem and pH value. Uncultured B. uniformis (T) and E. aerogenes may be responsible for degradation of L-try to skatole. © 2017 Blackwell

[Selective-differential nutrient medium "Shewanella IRHLS agar" for isolation of Shewanella genus bacteria].

PubMed

Sivolodsky, E P

2015-01-01

Development of a selective-differential nutrient medium for isolation of Shewanella genus bacteria. 73 strains of Shewanella bacteria (S. algae--3, S. baltica--26, S. putrefaciens--44) and 80 strains of 22 other bacteria genera were used. Shewanella species were identified by methods and criteria proposed by Nozue H. et al., 1992; Khashe S. et al., 1998. Nutrient media "Shewanella IRHLS Agar" for shewanella isolation was developed. Medium selective factors: irgazan DP-300 (I). 0.14-0.2 g/l and rifampicin (R) 0.0005-0.001 g/l. Shevanella colonies were detected by the production of hydrogen sulfide (H), lipase presence (L), lack of sorbitol fermentation (S). The medium suppressed the growth of hydrogen sulfide producers (Salmonella, Proteus) and blocked hydrogen sulfide production by Citrobacter. Growth of Escherichia, Enterobacter, Klebsiella, Shigella, Staphylococcus, Bacillus was also suppressed, Analytical sensitivity of the medium was 1-2 CFU/ml for Shewanella and Stenotrophomonas, Aerombnas, Serratia genera bacteria. 72 strains of Shewanella were isolated from water of Neva river in this medium, 91.7 ± 3.2% of those produced H2S. 1 strain of S. algae was isolated from clinical material. The developed media allows to use it in a complex for Stenotrophomo- nas sp., Aeromonas sp., Serratia sp., Citrobactersp. and Shewanella bacteria isolation.

[The frequency of bacteria in human gallstones].

PubMed

Lévay, Bernadett; Szabó, Györgyi; Szijártó, Attila; Gamal, Eldin Mohamed

2013-12-01

Complications caused by lost gallstones within the abdominal cavity are well known. Abscesses, perforation of the gastro-intestinal tract were all described in the literature, but gallstones were found in hernial sac, or even in sputum after it penetrated through the diaphragm into the respiratory tract. These complications can develop between several weeks to several years postoperatively. Most complications can be treated surgically only. Fifty gallstones and bile samples were collected from 50 patients who underwent cholecystectomy (36 female / 14 male, avarge age: 60.8 ± 6.8 years). All samples were sent for microbiological examination. bacterial colonization of the gallstone and the bile were found in 16 cases. Four of them showed acute inflammation in the gallbladder while pathological signs of chronic inflammation in the gallbladder wall were detected in eight cases. Empyema was found in four cases. Bacteria from enteral origin (Esherichia coli, Enterococcus faecalis, Enterobacter cloacae) was detected in 13 cases, while non-enteral (Klebsiella penumoniae, Streptococcus alfa-haemoliticus) colony were detected in three cases. Positive bacterial cultures were identified in twelve female and fourmale patients. Different types of bacteria can be found in the gallstones, which may cause various complications.

Deterioration to extinction of wastewater bacteria by non-thermal atmospheric pressure air plasma as assessed by 16S rDNA-DGGE fingerprinting

PubMed Central

El-Sayed, Wael S.; Ouf, Salama A.; Mohamed, Abdel-Aleam H.

2015-01-01

The use of cold plasma jets for inactivation of a variety of microorganisms has recently been evaluated via culture-based methods. Accordingly, elucidation of the role of cold plasma in decontamination would be inaccurate because most microbial populations within a system remain unexplored owing to the high amount of yet uncultured bacteria. The impact of cold atmospheric plasma on the bacterial community structure of wastewater from two different industries was investigated by metagenomic-based polymerase chain reaction-denaturing gradient gel electrophoresis (DGGE) utilizing 16S rRNA genes. Three doses of atmospheric pressure dielectric barrier discharge plasma were applied to wastewater samples on different time scales. DGGE revealed that the bacterial community gradually changed and overall abundance decreased to extinction upon plasma treatment. The bacterial community in food processing wastewater contained 11 key operational taxonomic units that remained almost completely unchanged when exposed to plasma irradiation at 75.5 mA for 30 or 60 s. However, when exposure time was extended to 90 s, only Escherichia coli, Coliforms, Aeromonas sp., Vibrio sp., and Pseudomonas putida survived. Only E. coli, Aeromonas sp., Vibrio sp., and P. putida survived treatment at 81.94 mA for 90 s. Conversely, all bacterial groups were completely eliminated by treatment at 85.34 mA for either 60 or 90 s. Dominant bacterial groups in leather processing wastewater also changed greatly upon exposure to plasma at 75.5 mA for 30 or 60 s, with Enterobacter aerogenes, Klebsiella sp., Pseudomonas stutzeri, and Acidithiobacillus ferrooxidans being sensitive to and eliminated from the community. At 90 s of exposure, all groups were affected except for Pseudomonas sp. and Citrobacter freundii. The same trend was observed for treatment at 81.94 mA. The variability in bacterial community response to different plasma treatment protocols revealed that plasma had a selective impact on bacterial

Molecular identification of coliform bacteria isolated from drinking water reservoirs with traditional methods and the Colilert-18 system.

PubMed

Kämpfer, Peter; Nienhüser, Anita; Packroff, Gabriele; Wernicke, Frank; Mehling, Arnd; Nixdorf, Katja; Fiedler, Stefanie; Kolauch, Claudia; Esser, Michael

2008-07-01

The accuracy of a traditional method (lactose utilization with acid and gas production) for the detection of coliform bacteria and E. coli was tested in comparison with method ISO 9308-1 (based on acid formation from lactose) and the Colilert-18 system (detection of beta-galactosidase). A total of 345 isolates were identified after isolation from water samples using API 20E strips. The Colilert-18 led to the highest number of positive findings (95% of the isolates were assigned to coliforms), whereas the ISO-9308-1 method resulted only in 29% coliform findings. With the traditional method only 15% were rated positive. Most of the isolates were identified by the API 20E system as Enterobacter spp. (species of the Enterobacter cloacae complex), Serratia spp., Citrobacter spp.and Klebsiella spp.; but species identification remained vague in several cases. A more detailed identification of 126 pure cultures by using 16S rRNA gene sequence analysis and analysis of the hsp60 gene resulted in the identification of Enterobacter nimipressuralis, E. amnigenus, E. asburiae, E. hormaechei, and Serratia fonticola as predominat coliforms. These species are beta-galactosidase positive, but show acid formation from lactose often after a prolonged incubation time. They are often not of fecal origin and may interfere with the ability to accurately detect coliforms of fecal origin.

Effect of Plant Growth Promoting Bacteria Associated with Halophytic Weed (Psoralea corylifolia L) on Germination and Seedling Growth of Wheat Under Saline Conditions.

PubMed

Sorty, Ajay M; Meena, Kamlesh K; Choudhary, Khushboo; Bitla, Utkarsh M; Minhas, P S; Krishnani, K K

2016-11-01

Halotolerant bacteria associated with Psoralea corylifolia L., a luxuriantly growing annual weed in salinity-affected semi-arid regions of western Maharashtra, India were evaluated for their plant growth-promoting activity in wheat. A total of 79 bacteria associated with different parts viz., root, shoot and nodule endophytes, rhizosphere, rhizoplane, and leaf epiphytes, were isolated and grouped based on their habitat. Twelve bacteria isolated for their potential in plant growth promotion were further selected for in vitro studies. Molecular identification showed the presence of the genera Bacillus, Pantoea, Marinobacterium, Acinetobacter, Enterobacter, Pseudomonas, Rhizobium, and Sinorhizobium (LC027447-53; LC027455; LC027457, LC027459, and LC128410). The phylogenetic studies along with carbon source utilization profiles using the Biolog® indicated the presence of novel species and the in planta studies revealed promising results under salinity stress. Whereas the nodule endophytes had minute plant growth-promoting (PGP) activity, the cell free culture filtrates of these strains enhanced seed germination of wheat (Triticum aestivum L). The maximum vigor index was monitored in isolate Y7 (Enterobacter sp strain NIASMVII). Indole acetic acid (IAA) production by the isolates ranged between 0.22 and 25.58 μg mL -1 . This signifies the need of exploration of their individual metabolites for developing next-generation bio-inoculants through co-inoculation with other compatible microbes. This study has potential in utilization of the weed-associated microbiome in terms of alleviation of salinity stress in crop plants.

NDM-1 encoded by a pNDM-HN380-like plasmid pNDM-BJ03 in clinical Enterobacter cloacae.

PubMed

Lü, Yang; Liu, Wei; Liang, Hui; Zhao, Shulong; Zhang, Wei; Liu, Jia; Jin, Cheng; Hu, Hongyan

2018-02-01

A carbapenemase-producing Enterobacter cloacae hhy03 with a bla NDM-1 and bla SHV-12 -coharboring plasmid was isolated from a sputum specimen of a patient. This is the third nucleotide sequence report of bla NDM-1 -harboring plasmid from Enterobacter cloacae that have caused lethal infections in China, indicating the spread of NDM-1 by IncX3 plasmid between Enterobacteriaceae. Copyright © 2017. Published by Elsevier Inc.

Severe community-acquired Enterobacter pneumonia: a plea for greater awareness of the concept of health-care-associated pneumonia

PubMed Central

2011-01-01

Background Patients with Enterobacter community-acquired pneumonia (EnCAP) were admitted to our intensive care unit (ICU). Our primary aim was to describe them as few data are available on EnCAP. A comparison with CAP due to common and typical bacteria was performed. Methods Baseline clinical, biological and radiographic characteristics, criteria for health-care-associated pneumonia (HCAP) were compared between each case of EnCAP and thirty age-matched typical CAP cases. A univariate and multivariate logistic regression analysis was performed to determine factors independently associated with ENCAP. Their outcome was also compared. Results In comparison with CAP due to common bacteria, a lower leukocytosis and constant HCAP criteria were associated with EnCAP. Empiric antibiotic therapy was less effective in EnCAP (20%) than in typical CAP (97%) (p < 0.01). A delay in the initiation of appropriate antibiotic therapy (3.3 ± 1.6 vs. 1.2 ± 0.6 days; p < 0.01) and an increase in duration of mechanical ventilation (8.4 ± 5.2 vs. 4.0 ± 4.3 days; p = 0.01) and ICU stay were observed in EnCAP patients. Conclusions EnCAP is a severe infection which is more consistent with HCAP than with typical CAP. This retrospectively suggests that the application of HCAP guidelines should have improved EnCAP management. PMID:21569334

Reduction of selenite to elemental selenium by Enterobacter cloacae SLD1a-1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dungan, R.S.; Frankenberger, W.T. Jr.

1998-11-01

The facultative anaerobic bacterium Enterobacter cloacae strain SLD1a-1 was studied in washed cell suspensions to assess optimal conditions required for the reduction of selenite (SeO{sub 3}{sup 2{minus}}) to elemental selenium (Se{sup 0}). Enterobacter cloacae using glucose (1.4 mM) as an electron donor removed 79% of the added SeO{sub 3}{sup 2{minus}} from solution in 2.5 h. Optimal SeO{sub 3}{sup 2{minus}} reduction occurred at a pH of 6.5 and a temperature of 40 C. Carbohydrate sources arabinose, xylose, and sorbose were found to significantly enhance SeO{sub 3}{sup 2{minus}} reduction over that of glucose. The reduction of SeO{sub 3}{sup 2{minus}} at 7.9 {micro}Mmore » was inhibited by nitrate of levels 1 to 100 times greater, nitrite at levels 5 and 10 times greater, while sulfite at levels of two to four times greater was found to stimulate the reduction of SeO{sub 3}{sup 2{minus}}. Enterobacter cloacae grows on anaerobically incubated plates containing NO{sub 3}{sup {minus}} as the sole terminal electron acceptor and acetate as the electron donor. Use of SeO{sub 3}{sup 2{minus}} as the terminal electron acceptor during anaerobic respiration did not support growth and could only be reduced to Se{sup 0} when NO{sub 3}{sup {minus}} was present.« less

Isolation of the opdE gene that encodes for a new hydrolase of Enterobacter sp. capable of degrading organophosphorus pesticides.

PubMed

Chino-Flores, Concepción; Dantán-González, Edgar; Vázquez-Ramos, Alejandra; Tinoco-Valencia, Raunel; Díaz-Méndez, Rafael; Sánchez-Salinas, Enrique; Castrejón-Godínez, Maria Luisa; Ramos-Quintana, Fernando; Ortiz-Hernández, Maria Laura

2012-06-01

Microbial enzymes that can hydrolyze organophosphorus compounds have been isolated, identified and characterized from different microbial species in order to use them in biodegradation of organophosphorus compounds. We isolated a bacterial strain Cons002 from an agricultural soil bacterial consortium, which can hydrolyze methyl-parathion (MP) and other organophosphate pesticides. HPLC analysis showed that strain Cons002 is capable of degrading pesticides MP, parathion and phorate. Pulsed-field gel electrophoresis and 16S rRNA amplification were performed for strain characterization and identification, respectively, showing that the strain Cons002 is related to the genus Enterobacter sp. which has a single chromosome of 4.6 Mb and has no plasmids. Genomic library was constructed from DNA of Enterobacter sp. Cons002. A gene called opdE (Organophosphate Degradation from Enterobacter) consists of 753 bp and encodes a protein of 25 kDa, which was isolated using activity methods. This gene opdE had no similarity to any genes reported to degrade organophosphates. When kanamycin-resistance cassette was placed in the gene opdE, hydrolase activity was suppressed and Enterobacter sp. Cons002 had no growth with MP as a nutrients source.

The filter-feeding ciliates Colpidium striatum and Tetrahymena pyriformis display selective feeding behaviours in the presence of mixed, equally-sized, bacterial prey.

PubMed

Thurman, Jill; Parry, Jacqueline D; Hill, Philip J; Laybourn-Parry, Johanna

2010-10-01

This study examined whether two ciliates could discriminate between equally-sized bacterial prey in mixture and if so, how selectivity might benefit the ciliate population. Live Klebsiella aerogenes, K. ozaenae and Escherichia coli, expressing different coloured fluorescent proteins, were cultured in such a way as to provide populations containing equally-sized cells (to prevent size-selective grazing taking place) and these prey were fed to each ciliate in 50:50 mixtures. Colpidium striatum selected K. aerogenes over K. ozaenae which itself was selected over E. coli. Tetrahymena pyriformis showed no selectivity between K. aerogenes and E. coli but K. aerogenes was selected over K. ozaenae while E. coli was not. This apparent selection of K. aerogenes over K. ozaenae was sustained in ciliate populations with different feeding histories and when K. aerogenes comprised only 20% of the prey mixture, suggesting possible optimal foraging behaviour. The metabolic benefits for selecting K. aerogenes were identified as possibly being an increase in cell biovolume and yield for C. striatum and T. pyriformis, respectively. The mechanism by which these ciliates selected specific bacterial cells in mixture is currently unknown but the use of live fluorescent bacteria, in prey mixtures, offers an exciting avenue for further investigation of selective feeding by protozoa. Copyright 2010 Elsevier Ltd. All rights reserved.

Comparison of Chromogenic Selective Media for the Detection of Cronobacter spp. (Enterobacter sakazakii).

PubMed

Teramura, Hajime; Fukuda, Noriko; Okada, Yumiko; Ogihara, Hirokazu

2018-01-01

　The four types of chromogenic selective media that are commercially available in Japan were compared for establishing a Japanese standard method for detecting Cronobacter spp. based on ISO/TS 22964:2006. When assessed using 9 standard Cronobacter spp. strains and 29 non-Cronobacter strains, Enterobacter sakazakii isolation agar, Chromocult TM Enterobacter sakazakii agar, CHROMagar TM E. sakazakii, and XM-sakazakii agar demonstrated excellent inclusivity and exclusivity. Using the ISO/TS 22964:2006 method, the recovered numbers of 38 Cronobacter spp. strains, including 29 C. sakazakii isolates obtained from each medium, were equivalent, indicating that there was no significant difference (p > 0.05) among the four types of chromogenic selective media. Thus, we demonstrated that these four chromogenic selective media are suitable alternatives when using the standard method for detecting Cronobacter spp. in Japan, based on the ISO/TS 22964:2006.

Antimicrobial isothiocyanates from the seeds of Moringa oleifera Lam.

PubMed

Padla, Eleanor P; Solis, Ludivina T; Levida, Ruel M; Shen, Chien-Chang; Ragasa, Consolacion Y

2012-01-01

4-(alpha-L-Rhamnosyloxy)benzyl isothiocyanate (1) and 4-(4'-O-acetyl-alpha-L-rhamnosyloxy)-benzyl isothiocyanate (2) isolated from Moringa oleifera seeds were screened for their antibacterial activities against Staphylococcus aureus, Staphylococcus epidermidis, Bacillus subtilis, Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, and Pseudomonas aeruginosa, and for their antifungal activities against Candida albicans, Trichophyton rubrum, and Epidermophyton floccosum using the disk diffusion method. Isothiocyanates 1 and 2 were found active at the lowest inhibitory concentration of 1 mg/ml against all Gram-positive bacteria tested (S. aureus, S. epidermidis, B. subtilis) and against the dermatophytic fungi E. floccosum and T. rubrum. Statistically significant differences were found between the mean inhibition zones (IZ) of 1 and 2 and the standard drugs, ofloxacin and clotrimazole. The minimum inhibitory concentration (MIC) values confirmed the good antimicrobial activity of 1 and 2 against S. aureus, good to moderate activity against S. epidermidis, moderate activity against B. subtilis, and weak activity against E. floccosum and T. rubrum. The in vitro bactericidal effect of 1 and 2 against the Gram-positive bacterial strains tested is suggested by MBC:MIC ratios of 2:1.

Antibacterial, anti-inflammatory and probiotic potential of Enterococcus hirae isolated from the rumen of Bos primigenius.

PubMed

Arokiyaraj, Selvaraj; Hairul Islam, Villianur Ibrahim; Bharanidharan, R; Raveendar, Sebastian; Lee, Jinwook; Kim, Do Hyung; Oh, Young Kyoon; Kim, Eun-Kyung; Kim, Kyoung Hoon

2014-07-01

In the present study bacterial strains were isolated from the rumen fluids of Bos primigenius and investigated their in vitro probiotic properties with potent antibacterial activity and anti-inflammatory effects. 9 g positive bacterial isolates were obtained and three isolates could able to tolerate gastric conditions, high bile salt concentrations and exhibited significant bactericidal effect against the enteric pathogens Vibrio cholera, Enterococcus faecalis, Enterobacter aerogens, Pseudomonas aeruginosa, Escherichia coli and Salmonella typhi. Moreover it showed above 70% cell surface hydrophobicity, significant low-invasion ability and potential adherence capacity in Caco-2 cells when compared with the control. The proinflammatory cytokines (TNF-α) was greatly reduced in rumen bacteria treatment and ARBS-1 modulate the immune response by activating the IL-4 secretion in parallel to TNF-α suppression. The 16s rRNA gene sequence of the active isolates were identified as Enterococcus hirae (ARBS-1), Pediococcus acidilactici (ARBS-4) and Bacillus licheniformis (ARBS-7). This study revealed the probiotic bactericidal properties of E. hirae obtained from the rumen of B. primigenius with potential antibacterial and anti-inflammatory effects. Future studies with the strains may yield some novel probiotic product for livestock's.

Antibacterial and Antimycotic Activity of Cotton Fabrics, Impregnated with Silver and Binary Silver/Copper Nanoparticles

NASA Astrophysics Data System (ADS)

Eremenko, A. M.; Petrik, I. S.; Smirnova, N. P.; Rudenko, A. V.; Marikvas, Y. S.

2016-01-01

Effective method of obtaining of the bactericidal bandage materials by impregnation of cotton fabric by aqueous solutions of silver and copper salts followed by a certain regime of heat treatment is developed. The study of obtained materials by methods of optical spectroscopy, electron microscopy, and X-ray phase analysis showed the formation of crystalline silver nanoparticles (NPs) and bimetallic Ag/Cu composites with the corresponding surface plasmon resonance (SPR) bands in the absorption spectra. High antimicrobial and antimycotic properties of tissues with low concentrations of Ag and Ag/Cu nanoparticles (Ag/Cu NPs) (in the range 0.06-0.25 weight percent (wt%) for Ag and 0.015-0.13 wt% for Ag/Cu) is confirmed in experiments with a wide range of multidrug-resistant bacteria and fungi: Escherichia coli, Enterobacter aerogenes, Proteus mirabilis, Klebsiella pneumoniae, Candida albicans yeasts, and micromycetes . Textile materials with Ag NPs demonstrate high antibacterial activity, while fabrics doped with bimetallic composite Ag/Cu have pronounced antimycotic properties. Bactericidal and antifungal properties of the obtained materials do not change after a washing. Production of such materials is extremely fast, convenient, and cost-effective.

[Bile-resistant Gram-negative bacteria effect of different kinds of root decoction pieces].

PubMed

Deng, Yan; Wang, Ya-Ke; Han, Xiao-Yu; Wang, Ya-Qi; Jiang, Zhen-Yu; Yu, Zhi-Jun; Deng, Hai-Ying

2017-11-01

To investigate the microbial contamination in Chinese herbal decoction pieces with different functional types by studying the total aerobic microbial count (TAMC), and total yeast and mould count (TYMC) in 40 samples of 8 types of root decoction pieces; further evaluate the contamination load of bile-resistant Gram-negative bacteria, and identify the Gram-negative bacteria by using biochemical identification system for Gram-negative bacteria. Our results showed that the TAMC value was more than 1 000 CFU•g⁻¹ in 85% (34/40) samples, and was more than 100 CFU•g⁻¹ in 30% (12/40) samples; the contamination of bile-resistant Gram-negative bacteria was detected in 45% (18/40) of the samples. The bile-resistant Gram-negative bacteria load of seven batches of samples was N>1 000 MPN•g⁻¹. Sixteen bacterium strains including Serratia plymouthensis, Cedecea neteri, Escherichia vulneris, Klebsiella oxytoca, Enterobacter amnigenus, E. cloacae, E. sakazakii, Proteus penneri and E. gergoviae were obtained and identified. E. cloacae was the predominant bacterium that was isolated from Salviae Miltiorrhizae Radix et Rhizoma, while E. amnigenus, Yersinia pseudotuberculosis was the typical bacterium of Ophiopogonis Radix and Codonopsis Radix, respectively. All these suggested that the contamination of bile-resistant Gram-negative bacteria was severe for the root decoction pieces in Wuhan city. Microbial species have certain selection specificity for medicinal ingredients, so the type and limit of control bacteria for detection should be formulated according to the pollution type and quantity of bile-resistant Gram-negative bacteria. Copyright© by the Chinese Pharmaceutical Association.

The Effectiveness of Heterotrophic Bacteria Isolated from Dumai Marine Waters of Riau, Used as Antibacterial against Pathogens in Fish Culture

NASA Astrophysics Data System (ADS)

Feliatra, F.; Nursyirwani; Tanjung, A.; Adithiya, DS; Susanna, M.; Lukystyowati, I.

2018-02-01

Heterotrophic bacteria have an important role as decomposer of organic compounds (mineralization) derived from industrial waste, decomposition of unconsumed feed, faecal, excretion of fish, and have the ability to inhibit the growth of pathogenic bacteria. We investigated the role of heterotrophic bacteria used as antibacterial against pathogens in fish culture.This research was conducted from January until March 2017. The phylogenitic of the isolated bacterial was determined by 16S rDNA sequences analysis. Antagonism test showed that the bacteria had the ability to inhibit the growth of pathogenic bacteria (Vibrio alginolyticus, Aeromonas hydrophila and Pseudomonas sp.) Three isolates (Dm5, Dm6 and Dm4) indicated high inhibition zones which were classified into strong category with the average from 10.5 to 11.8 mm toward V. alginolitycus. Other isolates were classified into medium and weak category. Based on DNA analysis of heterotrophic bacteria isolated from marine waters of industrial area and low salinity of estuarine waters twelve strains of bacteria were identified, and all had highest level of homology to Bacillus sp.,one isolates has similarity to Enterobacter cloacae, other isolates to Clostridium cetobutylicum. Most of isolated bacteria obtained from the waters of industrial area due to it received much of nutrients that very influenced the growth of bacteria.

Evolution of granulomas in lungs of mice infected aerogenically with Mycobacterium tuberculosis.

PubMed

Cardona, P J; Llatjós, R; Gordillo, S; Díaz, J; Ojanguren, I; Ariza, A; Ausina, V

2000-08-01

Aerogenous infection of C57Bl/6 mice with a virulent strain of Mycobacterium tuberculosis (CL 511) leads to the formation of primary granulomas in the lung where neutrophils, macrophages and subsequently, lymphocytes accumulate progressively around an initial cluster of infected macrophages. The spread of infection through the lung parenchyma gives rise to secondary granulomas featuring numerous lymphocytes that surround a small number of infected macrophages. Afterwards, foamy macrophages add an outer layer to the granulomas, which characteristically respect the pulmonary interstitium and remain confined within the alveolar spaces. This feature, in conjunction with the constant presence of M. tuberculosis in the products of broncho-alveolar lavage, suggests that the upward bronchial migration of infected macrophages may contribute significantly to pulmonary dissemination of mycobacterial infection. The latter would be in agreement with the persistence of chronic pulmonary infection in spite of a concomitant strong T helper 1 cell response.

Cadmium and cadmium-tolerant soil bacteria in cacao crops from northeastern Colombia.

PubMed

Bravo, D; Pardo-Díaz, S; Benavides-Erazo, J; Rengifo-Estrada, G; Braissant, O; Leon-Moreno, C

2018-05-01

This research aims to assess total-cadmium soil content and microbiological aspects to understand the dynamics of culturable cadmium-tolerant bacteria (CdtB) in cacao soils from northeastern Colombia. An integration of inverted dish plating, Cd determination and a microcalorimetry assay (IMC) was carried out. A farm in Boyacá showed the highest level of total soil Cd (3·74 mg kg -1 ) followed by farms in Santander and Arauca (2·76 and 1·16 mg kg -1 , respectively). Coefficient of determination between total soil Cd and CFU of CdtB was high (R 2  = 0·83) for the farm in Boyacá. Moreover, a pool of 129 CdtB was isolated, and phylogeny of 21 CdtB was discussed. Among CdtB strains isolated, Enterobacter sp. CdDB41 showed major Cd immobilization capacity (Q max of 2·21 and 2·32 J at 6 and 24 mg l -1 of CdCl 2 ), with an immobilization rate of 0·220 mg kg -1  h -1 . Among CdtB strains isolated, Enterobacter sp. CdDB41 showed major Cd immobilization capacity (Q max of 2·21 and 2·32 J at 6 and 24 mg l -1 of CdCl 2 ), with an immobilization rate of 0·220 mg kg -1  h -1 . Nothing is known about soil CdtB in cacao. Our data showed that CdtB such as Enterobacter sp. has high immobilization capacity. Furthermore, the otavite found in situ might be mineralized due to the bacterial metabolic activity of CdtB. © 2018 The Society for Applied Microbiology.

Thin-layer chromatographic technique for rapid detection of bacterial phospholipases.

PubMed

Legakis, N J; Papavassiliou, J

1975-11-01

Silica gel thin-layer chromatography was employed to detect lecithinase activity induced from bacterial resting cell preparations induced from bacterial resting cell preparations incubated at 37 C for 4 h in the presence of purified egg yolk lecithin. Bacillus subtilis, Bacillus cereus, Serratia marcescens, and Pseudomonas aeruginosa hydrolyzed lecithin with the formation of free fatty acids as the sole lipid-soluble product. In none of the Escherichia coli and Citrobacter freundii strains tested could lecithinase activity be detected. Four among eight strains of Enterobacter aerogenes and one among 12 strains of Proteus tested produced negligible amounts of free fatty acid.

Antimicrobial activity of essential oil from Schinus molle Linn.

PubMed

Gundidza, M

1993-11-01

The essential oil from the fresh leaves of Schinus molle isolated by hydrodistillation was tested for antibacterial activity using the hole plate diffusion method and for antifungal activity using the mycelium or single cell growth inhibition method. Results obtained showed that the volatile oil exhibited significant activity against the following bacterial species: Klebsiella pneumoniae, Alcaligenes faecalis, Pseudomonas aeruginosa, Leuconostoc cremoris, Enterobacter aerogenes, Proteus vulgaris, Clostridium sporogenes, Acinetobacter calcoacetica, Escherichia coli, Beneckea natriegens, Citrobacter freundii, Serratia marcescens, Bacillus subtilis and Brochothrix thermosphacata. The fungal species Aspergillus ochraceus, Aspergillus parasiticus, Fusarium culmorum and Alternaria alternata exhibited significant sensitivity to the volatile oil.

Bioethanol production from mannitol by a newly isolated bacterium, Enterobacter sp. JMP3.

PubMed

Wang, Jing; Kim, Young Mi; Rhee, Hong Soon; Lee, Min Woo; Park, Jong Moon

2013-05-01

In this study a new bacterium capable of growing on brown seaweed Laminaria japonica, Enterobacter sp. JMP3 was isolated from the gut of turban shell, Batillus cornutus. In anaerobic condition, it produced high yields of ethanol (1.15 mol-EtOH mol-mannitol(-1)) as well as organic acids from mannitol, the major carbohydrate component of L. japonica. Based on carbon distribution and metabolic flux analysis, it was revealed that mannitol was more favorable than glucose for ethanol production due to their different redox states. This indicates that L. japonica is one of the promising feedstock for bioethanol production. Additionally, the mannitol dehydrogenation pathway in Enterobacter sp. JMP3 was examined and verified. Finally, an attempt was made to explore the possibility of controlling ethanol production by altering the redox potential via addition of external NADH in mannitol fermentation. Copyright © 2012 Elsevier Ltd. All rights reserved.

Diversity of microflora in the gut and casts of tropical composting earthworms reared on different substrates.

PubMed

Parthasarathi, K; Ranganathan, L S; Anandi, V; Zeyer, Josef

2007-01-01

The diversity of fungi, bacteria, yeast, actinomycetes and protozoa were analysed in the gut and casts of Eudrilus eugeniae, Lampito mauritii, Eisenia fetida and Perionyx excavatus, both qualitatively and quantitatively as influenced by different feed substrates like clay loam soil, cowdung and pressmud. While actinomycetes (Streptomyces albus, S. somaliensis, Nocardia asteroides, N. caviae and Saccharomonosporia) were not digested by any of these species of worms, protozoa (Amoeba proteus, A. terricola, Paramecium trichium, Euglena viridis, E. orientalis, Vorticella picta and Trichomonas hominis) and yeast (Candida tropicalis, C. krusei C. albicans and Cryptococcus neoformans) were totally digested. Certain species of fungi (Saksenae vasiformis, Mucor plumbeus, Cladosporium carrionii, C. herbacium, Alternaria sp., Cunninghamella echinulata, Mycetia sterila, Syncephalostrum racemosum, Curvalaria lunata, C. geniculata and Geotrichum candidum) and bacteria (Pseudomonas aeruginosa, Bacterium antitratum, Mima polymorpha, Enterobacter aerogenes, E. cloacae, Proteus vulgaris, P. mirabilis, P. rettgeri, Escherichia coli, Staphylococus citreus, Bacillus subtilis, B. cereus, Enterococci and Micrococci) were completely digested. Certain other species were not digested fungi like Aspergillus fumigatus, A. flavus, A. ochraceous, Trichoderma koningii (except by Eeugeniae), Fusarium moniliforme (except by E. eugeniae) and Rhizopus sp., and bacteria like Klebsiella pneumoniae and Morganella morganii) and these were multiplied during the transit of the organic residues through the gut of worms. The microbial proliferation was more in the casts, due to the environment prevailing--rich in nutrient supply and large surface area available for growth and reproduction of the microbes that lead to enhanced microbial activity and humic acid contents in the casts.

Microbial diversity and dynamics during the production of May bryndza cheese.

PubMed

Pangallo, Domenico; Saková, Nikoleta; Koreňová, Janka; Puškárová, Andrea; Kraková, Lucia; Valík, Lubomír; Kuchta, Tomáš

2014-01-17

Diversity and dynamics of microbial cultures were studied during the production of May bryndza cheese, a traditional Slovak cheese produced from unpasteurized ewes' milk. Quantitative culture-based data were obtained for lactobacilli, lactococci, total mesophilic aerobic counts, coliforms, E. coli, staphylococci, coagulase-positive staphylococci, yeasts, fungi and Geotrichum spp. in ewes' milk, curd produced from it and ripened for 0 - 10 days, and in bryndza cheese produced from the curd, in three consecutive batches. Diversity of prokaryotes and eukaryotes in selected stages of the production was studied by non-culture approach based on amplification of 16S rDNA and internal transcribed spacer region, coupled to denaturing gradient gel electrophoresis and sequencing. The culture-based data demonstrated an overall trend of growth of the microbial population contributing to lactic acid production and to ripening of the cheese, lactobacilli, lactococci and Geotrichum spp. growing up to densities of 10(8) CFU/g, 10(9) CFU/g and 10(5) CFU/g, respectively, in all three consecutive batches of bryndza cheese. The diversity of bacteria encompassed Acinetobacter calcoaceticus, Acinetobacter guillouiae, Acinetobacter sp., Acinetobacter johnsonii, Citrobacter braakii, Clostridium bartlettii, Corynebacterium callunae, Corynebacterium maris, Enterobacter aerogenes, Enterobacter asburiae, Enterobacter hormaechei, Enterococcus faecium, Enterococcus pallens, Escherichia coli, Haemophilus haemolyticus, Hafnia alvei, Kluyvera cryocrescens, Lactobacillus helveticus, Lactococcus garvieae, Lc. lactis subsp. cremoris, Lc. lactis subsp. lactis, "Leuconostoc garlicum", Mannheimia glucosida, Mannheimia haemolytica, Pseudomonas sp., Ps. fluorescens, "Ps. reactans", Raoultella ornithinolytica, R. terrigena, "Rothia arfidiae", Staphylococcus aureus, Staph. epidermidis, Staph. felis, Staph. pasteuri, Staph. sciuri, Staph. xylosus, Streptococcus parauberis, Str. thermophilus and Variovorax

Plant growth promotion and root colonization by EPS producing Enterobacter sp. RZS5 under heavy metal contaminated soil.

PubMed

Sayyed, R Z; Patel, P R; Shaikh, S S

2015-02-01

The heavy metal resistant bacterium isolated from field soil and identified as Enterobacter sp. RZS5 tolerates a high concentration (100-2000 μM) of various heavy metal ions such as Mn2+, Ni2+, Zn2+, Cu2+, CO2+ and Fe2+ when grown in such environment and produces exopolysaccharides (EPS). Here, we have demonstrated EPS production by Enterobacter sp. RZS5 during 60 h of growth in yeast extract mannitol broth (YEMB). The yield increased by two fold after the addition of 60 μM of Ca2+; 50 μM of Fe2+ and 60 μM of Mg2+ ions in YEMB, and the optimization of physico-chemical parameters. EPS was extracted with 30% (v/v) of isopropanol as against the commonly used 50% (v/v) isopropanol method. EPS-rich broth promoted seed germination, shoot height, root length, number of leaves and chlorophyll content of wheat (Triticum aestivum) seed and peanut (Arachis hypogaea) seed. The higher colony-forming unit of Enterobacter sp. in soil inoculated with EPS rich broth of Enterobacter sp. indicated the root colonizing potential and rhizosphere competence of the isolate. The FTIR spectra of the EPS extract confirmed the presence of the functional group characteristics of EPS known to exhibit a high binding affinity towards certain metal ions. This overall growth and vigour in plants along with the effective root colonization, reflected the potential of the isolate as an efficient bio-inoculant in bioremediation.

Bioremediation of heavy metal-contaminated effluent using optimized activated sludge bacteria

NASA Astrophysics Data System (ADS)

Bestawy, Ebtesam El.; Helmy, Shacker; Hussien, Hany; Fahmy, Mohamed; Amer, Ranya

2013-03-01

Removal of heavy metals from contaminated domestic-industrial effluent using eight resistant indigenous bacteria isolated from acclimatized activated sludge was investigated. Molecular identification using 16S rDNA amplification revealed that all strains were Gram-negative among which two were resistant to each of copper, cadmium and cobalt while one was resistant to each of chromium and the heavy metal mixture. They were identified as Enterobacter sp. (Cu1), Enterobacter sp. (Cu2), Stenotrophomonas sp. (Cd1), Providencia sp. (Cd2), Chryseobacterium sp. (Co1), Comamonas sp. (Co2), Ochrobactrum sp. (Cr) and Delftia sp. (M1) according to their resistance pattern. Strains Cu1, Cd1, Co2 and Cr were able to resist 275 mg Cu/l, 320 mg Cd/l, 140 mg Co/l and 29 mg Cr/l respectively. The four resistant strains were used as a mixture to remove heavy metals (elevated concentrations) and reduce the organic load of wastewater effluent. Results revealed that using the proposed activated sludge with the resistant bacterial mixture was more efficient for heavy metal removal compared to the activated sludge alone. It is therefore recommended that the proposed activated sludge system augmented with the acclimatized strains is the best choice to ensure high treatment efficiency and performance under metal stresses especially when industrial effluents are involved.

Alterations in the response of pigs to Salmonella typhimurium when provided Enterobacter cloacae

USDA-ARS?s Scientific Manuscript database

Weanling pigs are at risk of succumbing to illness due to an immature immune system and insufficient supply of available energy at the time of weaning. Recent evidence has suggested that providing pigs with Enterobacter cloacae can increase the concentration of circulating triglycerides (TAGs) and t...

Frequency and antimicrobial susceptibility of gram-negative bacteria isolated from 2 hospitals in Makkah, Saudi Arabia.

PubMed

Asghar, Atif H; Faidah, Hani S

2009-08-01

To estimate the prevalence and antibiotic susceptibility of the gram-negative bacteria isolated from 2 hospitals in Makkah. This study was undertaken in 2 main tertiary care hospitals namely; Al-Noor Specialist Hospital, and Hera Hospital in Makkah, Kingdom of Saudi Arabia from October 2005 to March 2006. A total of 1137 gram-negative bacteria were identified in non-duplicate clinical specimens obtained from 965 patients of various body sites infections. Demographic data, identity of microorganisms, and antimicrobial susceptibilities were obtained from medical and laboratory records. The most prevalent gram-negative bacteria were Escherichia coli (31.6%), and Pseudomonas aeruginosa (31.2%), followed by Acinetobacter baumannii (10.8%), Klebsiella pneumoniae (8.3%), Klebsiella sp. (6.2%), Haemophilus influenzae (3.7%), Proteus sp. (3.3%), and Enterobacter sp. (1.9%). Results demonstrated that gram-negative bacteria have a high rate of resistance to commonly used antibiotics. Furthermore, multi-drug resistance was also common in this study. Our data showed a high rate of resistance among gram-negative pathogens in comparison with other countries in the world. The implementation of monitoring programs is an important part of the prevention strategy against the development of antibiotic resistance in hospitals.

[Occupational exposure to airborne fungi and bacteria in a household recycled container sorting plant ].

PubMed

Solans, Xavier; Alonso, Rosa María; Constans, Angelina; Mansilla, Alfonso

2007-06-01

Several studies have showed an association between the work in waste treatment plants and occupational health problems such as irritation of skin, eyes and mucous membranes, pulmonary diseases, gastrointestinal problems and symptoms of organic dust toxic syndrome (ODTS). These symptoms have been related to bioaerosol exposure. The aim of this study was to investigate the occupational exposure to biological agents in a plant sorting source-separated packages (plastics materials, ferric and non-ferric metals) household waste. Airborne samples were collected with M Air T Millipore sampler. The concentration of total fungi and bacteria and gram-negative bacteria were determined and the most abundant genera were identified. The results shown that the predominant airborne microorganisms were fungi, with counts greater than 12,000 cfu/m(3) and gram-negative bacteria, with a environmental concentration between 1,395 and 5,280 cfu/m(3). In both cases, these concentrations were higher than levels obtained outside of the sorting plant. Among the fungi, the predominant genera were Penicillium and Cladosporium, whereas the predominant genera of gram-negative bacteria were Escherichia, Enterobacter, Klebsiella and Serratia. The present study shows that the workers at sorting source-separated packages (plastics materials, ferric and non-ferric metals) domestic waste plant may be exposed to airborne biological agents, especially fungi and gram-negative bacteria.

Determination for Enterobacter cloacae based on a europium ternary complex labeled DNA probe

NASA Astrophysics Data System (ADS)

He, Hui; Niu, Cheng-Gang; Zeng, Guang-Ming; Ruan, Min; Qin, Pin-Zhu; Liu, Jing

2011-11-01

The fast detection and accurate diagnosis of the prevalent pathogenic bacteria is very important for the treatment of disease. Nowadays, fluorescence techniques are important tools for diagnosis. A two-probe tandem DNA hybridization assay was designed for the detection of Enterobacter cloacae based on time-resolved fluorescence. In this work, the authors synthesized a novel europium ternary complex Eu(TTA) 3(5-NH 2-phen) with intense luminescence, high fluorescence quantum yield and long lifetime before. We developed a method based on this europium complex for the specific detection of original extracted DNA from E. cloacae. In the hybridization assay format, the reporter probe was labeled with Eu(TTA) 3(5-NH 2-phen) on the 5'-terminus, and the capture probe capture probe was covalent immobilized on the surface of the glutaraldehyde treated glass slides. The original extracted DNA of samples was directly used without any DNA purification and amplification. The detection was conducted by monitoring the fluorescence intensity from the glass surface after DNA hybridization. The detection limit of the DNA was 5 × 10 -10 mol L -1. The results of the present work proved that this new approach was easy to operate with high sensitivity and specificity. It could be conducted as a powerful tool for the detection of pathogen microorganisms in the environment.

Multifarious beneficial traits and plant growth promoting potential of Serratia marcescens KiSII and Enterobacter sp. RNF 267 isolated from the rhizosphere of coconut palms (Cocos nucifera L.).

PubMed

George, Priya; Gupta, Alka; Gopal, Murali; Thomas, Litty; Thomas, George V

2013-01-01

Two plant growth promoting bacteria designated as KiSII and RNF 267 isolated from the rhizosphere of coconut palms were identified as Serratia marcescens and Enterobacter sp. based on their phenotypic features, BIOLOG studies and 16S rRNA gene sequence analysis. Both bacteria exhibited phosphate solubilization, ammonification, and production of indole acetic acid, β-1, 3 glucanase activities and 1-aminocyclopropane-1-carboxylate-deaminase activity. They could also tolerate a range of pH conditions, low temperature and salinity (NaCl). In addition, S. marcescens KiSII exhibited N- fixation potential, chitinase activity, siderophore production and antibiotics production. Seed bacterization with these bacteria increased the growth parameters of test plants such as paddy and cowpea over uninoculated control in green house assay. In coconut seedlings, significant increase in growth and nutrient uptake accompanied with higher populations of plant beneficial microorganisms in their rhizospheres were recorded on inoculation with both the PGPRs. The present study clearly revealed that PGPRs can aid in production of healthy and vigorous seedlings of coconut palm which are hardy perennial crops. They offer a scope to be developed into novel PGPR based bioinoculants for production of elite seedlings that can benefit the coconut farming community and the coconut based ecology.

Evaluating Hawaii-Grown Papaya for Resistance to Internal Yellowing Disease Caused by Enterobacter cloacae

USDA-ARS?s Scientific Manuscript database

Papaya (Carica papaya L.) cultivars and breeding lines were evaluated for resistance to Enterobacter cloacae (Jordan) Hormaeche & Edwards, the bacterial causal agent of internal yellowing disease (IY), using a range of concentrations of the bacterium. Linear regression analysis was performed and IY ...

Comparison of methods for determining the numbers and species distribution of coliform bacteria in well water samples.

PubMed

Niemi, R M; Heikkilä, M P; Lahti, K; Kalso, S; Niemelä, S I

2001-06-01

Enumeration of coliform bacteria and Escherichia coli is the most widely used method in the estimation of hygienic quality of drinking water. The yield of target bacteria and the species composition of different populations of coliform bacteria may depend on the method.Three methods were compared. Three membrane filtration methods were used for the enumeration of coliform bacteria in shallow well waters. The yield of confirmed coliform bacteria was highest on Differential Coliform agar, followed by LES Endo agar. Differential Coliform agar had the highest proportion of typical colonies, of which 74% were confirmed as belonging to the Enterobacteriaceae. Of the typical colonies on Lactose Tergitol 7 TTC agar, 75% were confirmed as Enterobacteriaceae, whereas 92% of typical colonies on LES Endo agar belonged to the Enterobacteriaceae. LES Endo agar yielded many Serratia strains, Lactose Tergitol 7 TTC agar yielded numerous strains of Rahnella aquatilis and Enterobacter, whereas Differential Coliform agar yielded the widest range of species. The yield of coliform bacteria varied between methods. Each method compared had a characteristic species distribution of target bacteria and a typical level of interference of non-target bacteria. Identification with routine physiological tests to distinct species was hampered by the slight differences between species. High yield and sufficient selectivity are difficult to achieve simultaneously, especially if the target group is diverse. The results showed that several aspects of method performance should be considered, and that the target group must be distinctly defined to enable method comparisons.

Identification and production of bioflocculants by Enterobacter sp. and Bacillus sp. and their characterization studies.

PubMed

Muthulakshmi, L; Nellaiah, H; Kathiresan, T; Rajini, N; Christopher, Fenila

2017-05-28

In this work, two bioflocculants, namely, EB-EPS and B1-EPS, were derived from Enterobacter sp. and Bacillus sp., respectively, and analyzed with regard to their production and characterization. About 0.9 and 0.16 g of purified EB and B1 were obtained from I L of fermentation broth. Chemical analysis showed the contents of purified EB and B1 mainly as 88.7 and 92.8% (w/w) of carbohydrate, and 11.3 and 21.8% (w/w) protein, respectively. Fourier-transform infrared spectrometry analysis revealed the presence of hydroxyl, amide, and carboxyl groups in the identified bioflocculant. Thermogravimetric analysis (TGA) results exhibited enhanced thermal stability with a minimum mass loss of 50% while 25% were found to have occurred at higher temperatures (>400°C) for microbe-derived compounds EB and B1 leading to the possibility of using these compounds as fillers or for fabricating composite films for high-temperature applications. Further, the compounds from both the bacteria exhibited good antibacterial characteristics against pathogenic Escherichia coli. Degradability study of bioflocculant-embedded composite films shows the possibility of attaining eco-friendly bioremediation. Accordingly, experimental results revealed the suitability of developed composite films as a suitable alternative for food packaging and biomedical applications.

Exopolysaccharide produced by Enterobacter sp. YG4 reduces uranium induced nephrotoxicity.

PubMed

K, Nagaraj; Devasya, Rekha Punchapady; Bhagwath, Arun Ananthapadmanabha

2016-01-01

Uranium nephrotoxicity is a health concern with very few treatment options. Bacterial exopolysaccharides (EPS) possess multiple biological activities and appear as prospective candidates for treating uranium nephrotoxicity. This study focuses on the ability of an EPS produced by a bacterial strain Enterobacter sp. YG4 to reduce uranium nephrotoxicity in vivo. This bacterium was isolated from the gut contents of a slug Laevicaulis alte (Férussac). Based on the aniline blue staining reaction and infrared spectral analysis, the EPS was identified as β-glucan and its molecular weight was 11.99×10(6)Da. The EPS showed hydroxyl radical scavenging ability and total antioxidant capacity in vitro. To assess the protection provided by the EPS against uranium nephrotoxicity, a single dose of 2mg/kg uranyl nitrate was injected intraperitoneally to albino Wistar rats. As intervention, the EPS was administered orally (100mg/kg/day) for 4 consecutive days. The rats were sacrificed on the fifth day and analyses were conducted. Increased serum creatinine and urea nitrogen levels and histopathological alterations in kidneys were observed in uranyl nitrate treated animals. All these alterations were reduced with the administration of Enterobacter sp. YG4 EPS, emphasizing a novel approach in treating uranium nephrotoxicity. Copyright © 2015 Elsevier B.V. All rights reserved.

Conserved regulatory elements of the promoter sequence of the gene rpoH of enteric bacteria

PubMed Central

Ramírez-Santos, Jesús; Collado-Vides, Julio; García-Varela, Martin; Gómez-Eichelmann, M. Carmen

2001-01-01

The rpoH regulatory region of different members of the enteric bacteria family was sequenced or downloaded from GenBank and compared. In addition, the transcriptional start sites of rpoH of Yersinia frederiksenii and Proteus mirabilis, two distant members of this family, were determined. Sequences similar to the σ70 promoters P1, P4 and P5, to the σE promoter P3 and to boxes DnaA1, DnaA2, cAMP receptor protein (CRP) boxes CRP1, CRP2 and box CytR present in Escherichia coli K12, were identified in sequences of closely related bacteria such as: E.coli, Shigella flexneri, Salmonella enterica serovar Typhimurium, Citrobacter freundii, Enterobacter cloacae and Klebsiella pneumoniae. In more distant bacteria, Y.frederiksenii and P.mirabilis, the rpoH regulatory region has a distal P1-like σ70 promoter and two proximal promoters: a heat-induced σE-like promoter and a σ70 promoter. Sequences similar to the regulatory boxes were not identified in these bacteria. This study suggests that the general pattern of transcription of the rpoH gene in enteric bacteria includes a distal σ70 promoter, >200 nt upstream of the initiation codon, and two proximal promoters: a heat-induced σE-like promoter and a σ70 promoter. A second proximal σ70 promoter under catabolite-regulation is probably present only in bacteria closely related to E.coli. PMID:11139607

Smartphone-based rapid quantification of viable bacteria by single-cell microdroplet turbidity imaging.

PubMed

Cui, Xiaonan; Ren, Lihui; Shan, Yufei; Wang, Xixian; Yang, Zhenlong; Li, Chunyu; Xu, Jian; Ma, Bo

2018-05-18

Standard plate count (SPC) has been recognized as the golden standard for the quantification of viable bacteria. However, SPC usually takes one to several days to grow individual cells into a visible colony, which greatly hampers its application in rapid bacteria enumeration. Here we present a microdroplet turbidity imaging based digital standard plate count (dSPC) method to overcome this hurdle. Instead of cultivating on agar plates, bacteria are encapsulated in monodisperse microdroplets for single-cell cultivation. Proliferation of the encapsulated bacterial cell produced a detectable change in microdroplet turbidity, which allowed, after just a few bacterial doubling cycles (i.e., a few hours), enumeration of viable bacteria by visible-light imaging. Furthermore, a dSPC platform integrating a power-free droplet generator with smartphone-based turbidity imaging was established. As proof-of-concept demonstrations, a series of Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Bacillus subtilis) samples were quantified via the smartphone dSPC accurately within 6 hours, representing a detection sensitivity of 100 CFU ml-1 and at least 3 times faster. In addition, Enterobacter sakazakii (E. sakazakii) in infant milk powder as a real sample was enumerated within 6 hours, in contrast to the 24 hours needed in traditional SPC. Results with high accuracy and reproducibility were achieved, with no difference in counts found between dSPC and SPC. By enabling label-free, rapid, portable and low-cost enumeration and cultivation of viable bacteria onsite, smartphone dSPC forms the basis for a temporally and geographically trackable network for surveying live microbes globally where every citizen with a cellphone can contribute anytime and anywhere.

Entericidin is required for a probiotic treatment (Enterobacter sp. strain C6-6) to protect trout from cold-water disease challenge.

PubMed

Schubiger, Carla B; Orfe, Lisa H; Sudheesh, Ponnerassery S; Cain, Kenneth D; Shah, Devendra H; Call, Douglas R

2015-01-01

Flavobacterium psychrophilum causes bacterial cold-water disease in multiple fish species, including salmonids. An autochthonous Enterobacter strain (C6-6) inhibits the in vitro growth of F. psychrophilum, and when ingested as a putative probiotic, it provides protection against injection challenge with F. psychrophilum in rainbow trout. In this study, low-molecular-mass (≤3 kDa) fractions from both Enterobacter C6-6 and Escherichia coli K-12 culture supernatants inhibited the growth of F. psychrophilum. The ≤3-kDa fraction from Enterobacter C6-6 was analyzed by SDS-PAGE, and subsequent tandem mass spectroscopy identified EcnB, which is a small membrane lipoprotein that is a putative pore-forming toxin. Agar plate diffusion assays demonstrated that ecnAB knockout strains of both Enterobacter C6-6 and E. coli K-12 no longer inhibited F. psychrophilum (P < 0.001), while ecnAB-complemented knockout strains recovered the inhibitory phenotype (P < 0.001). In fish experiments, the engineered strains (C6-6 ΔecnAB and C6-6 ΔecnAB) and the wild-type strain (C6-6) were added to the fish diet every day for 38 days. On day 11, the fish were challenged by injection with a virulent strain of F. psychrophilum (CSF 259-93). Fish that were fed C6-6 had significantly longer survival than fish fed the ecnAB knockout strain (P < 0.0001), while fish fed the complemented knockout strain recovered the probiotic phenotype (P = 0.61). This entericidin is responsible for the probiotic activity of Enterobacter C6-6, and it may present new opportunities for therapeutic and prophylactic treatments against similarly susceptible pathogens. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Entericidin Is Required for a Probiotic Treatment (Enterobacter sp. Strain C6-6) To Protect Trout from Cold-Water Disease Challenge

PubMed Central

Schubiger, Carla B.; Orfe, Lisa H.; Sudheesh, Ponnerassery S.; Cain, Kenneth D.; Shah, Devendra H.

2014-01-01

Flavobacterium psychrophilum causes bacterial cold-water disease in multiple fish species, including salmonids. An autochthonous Enterobacter strain (C6-6) inhibits the in vitro growth of F. psychrophilum, and when ingested as a putative probiotic, it provides protection against injection challenge with F. psychrophilum in rainbow trout. In this study, low-molecular-mass (≤3 kDa) fractions from both Enterobacter C6-6 and Escherichia coli K-12 culture supernatants inhibited the growth of F. psychrophilum. The ≤3-kDa fraction from Enterobacter C6-6 was analyzed by SDS-PAGE, and subsequent tandem mass spectroscopy identified EcnB, which is a small membrane lipoprotein that is a putative pore-forming toxin. Agar plate diffusion assays demonstrated that ecnAB knockout strains of both Enterobacter C6-6 and E. coli K-12 no longer inhibited F. psychrophilum (P < 0.001), while ecnAB-complemented knockout strains recovered the inhibitory phenotype (P < 0.001). In fish experiments, the engineered strains (C6-6 ΔecnAB and C6-6 ΔecnAB) and the wild-type strain (C6-6) were added to the fish diet every day for 38 days. On day 11, the fish were challenged by injection with a virulent strain of F. psychrophilum (CSF 259-93). Fish that were fed C6-6 had significantly longer survival than fish fed the ecnAB knockout strain (P < 0.0001), while fish fed the complemented knockout strain recovered the probiotic phenotype (P = 0.61). This entericidin is responsible for the probiotic activity of Enterobacter C6-6, and it may present new opportunities for therapeutic and prophylactic treatments against similarly susceptible pathogens. PMID:25381243

Removal enactment of organo-phosphorous pesticide using bacteria isolated from domestic sewage.

PubMed

Shabbir, Md; Singh, Mukesh; Maiti, Swati; Kumar, Sunil; Saha, Samar K

2018-05-01

Three bacteria (MS I, II and III) i.e., Pseudomonas aeruginosa (KY781886), Enterobactor ludwigii (KX881423) and Enterobacter cloacae (KX881513) isolated from domestic sewage were identified on the basis of 16S rDNA sequencing and are capable to growth in the presence of organo-phosphorous pesticide (chlorpyrifos). The mega plasmid size >23 kb was found in MS I and III. Biosurfactants of the significant amount were produced by three isolates. The ability of the isolates to degrade pesticide over 3 days in the presence of pesticides containing chlorpyrifos as the active component was estimated. Results of UV-visible, FTIR spectroscopy and GC-MS studies confirmed the removal of chlorpyrifos rather than degradation. Pesticide uptake results showed chlorpyrifos in intracellular components and bound to the cell surface in its native state. Removal of pesticide from soil was also recorded by these bacteria. Microbial treated pesticide did not have any effect on Vigna radita seedlings and goat erythrocytes. Copyright © 2018 Elsevier Ltd. All rights reserved.

Stimulation of the growth of Jatropha curcas by the plant growth promoting bacterium Enterobacter cancerogenus MSA2.

PubMed

Jha, Chaitanya Kumar; Patel, Baldev; Saraf, Meenu

2012-03-01

A novel Enterobacter cancerogenus MSA2 is a plant growth promoting gamma-proteobacterium that was isolated from the rhizosphere of Jatropha cucas a potentially important biofuel feed stock plant. Based on phenotypic, physiological, biochemical and phylogenetic studies, strain MSA2 could be classified as a member of E. cancerogenus. However, comparisons of characteristics with other known species of the genus Enterobacter suggested that strain MSA2 could be a novel PGPB strain. In vitro studies were carried for the plant growth promoting attribute of this culture. It tested positive for ACC (1-aminocyclopropane-1-carboxylic acid) deaminase production, phytase, phosphate solubilization, IAA (Indole acetic acid) production, siderophore, and ammonia production. The isolate was then used as a inoculant for the vegetative study of Jatropha curcas plant. Enterobacter cancerogenus MSA2 supplemented with 1% carboxymethylcellulose showed overall plant growth promotion effect resulting in enhanced root length (124.14%), fresh root mass (81%), fresh shoot mass (120.02%), dry root mass (124%), dry shoot mass (105.54%), number of leaf (30.72%), chlorophyll content (50.41%), and biomass (87.20%) over control under the days of experimental observation. This study was designed for 120 days and was in triplicate and the data was collected at every 30 days.

Prevalence and impact of extended-spectrum β-lactamase production on clinical outcomes in cancer patients with Enterobacter species bacteremia

PubMed Central

Kim, Sun Jong; Park, Ki-Ho; Chung, Jin-Won; Sung, Heungsup; Choi, Sang-Ho

2014-01-01

Background/Aims We examined the prevalence of extended-spectrum β-lactamase (ESBL) production and the impact of ESBL on clinical outcomes in cancer patients with Enterobacter spp. bacteremia. Methods Using prospective cohort data on Enterobacter bacteremia obtained between January 2005 and November 2008 from a tertiary care center, the prevalence and clinical impact of ESBL production were evaluated. Results Two-hundred and three episodes of Enterobacter spp. bacteremia were identified. Thirty-one blood isolates (15.3%, 31/203) scored positive by the double-disk synergy test. Among 17 isolates in which ESBL genes were detected by polymerase chain reaction and sequencing, CTX-M (n = 12), SHV-12 (n = 11), and TEM (n = 4) were the most prevalent ESBL types. Prior usage of antimicrobial agents (77.4% vs. 54.0%, p = 0.02) and inappropriate empirical antimicrobial therapy (22.6% vs. 3.0%, p < 0.001) were more commonly encountered in the ESBL-positive group than in the extended-spectrum cephalosporin-susceptible ESBL-negative group, respectively. Clinical outcomes did not differ significantly between the two groups (30-day mortality rate, 19.4% vs. 17.0%, p = 0.76; median length of hospital stay, 24.0 days vs. 30.5 days, p = 0.97). Initial presentation of severe sepsis/septic shock, pneumonia, and intra-abdominal infection were independently associated with 30-day mortality. Conclusions The prevalence of ESBL-producing isolates was 15.3% in cancer patients with Enterobacter bacteremia. Although inappropriate empirical therapy was more common in the ESBL-positive group, ESBL production was not associated with poorer outcomes. PMID:25228840

Prevalence and impact of extended-spectrum β-lactamase production on clinical outcomes in cancer patients with Enterobacter species bacteremia.

PubMed

Kim, Sun Jong; Park, Ki-Ho; Chung, Jin-Won; Sung, Heungsup; Choi, Seong-Ho; Choi, Sang-Ho

2014-09-01

We examined the prevalence of extended-spectrum β-lactamase (ESBL) production and the impact of ESBL on clinical outcomes in cancer patients with Enterobacter spp. bacteremia. Using prospective cohort data on Enterobacter bacteremia obtained between January 2005 and November 2008 from a tertiary care center, the prevalence and clinical impact of ESBL production were evaluated. Two-hundred and three episodes of Enterobacter spp. bacteremia were identified. Thirty-one blood isolates (15.3%, 31/203) scored positive by the double-disk synergy test. Among 17 isolates in which ESBL genes were detected by polymerase chain reaction and sequencing, CTX-M (n = 12), SHV-12 (n = 11), and TEM (n = 4) were the most prevalent ESBL types. Prior usage of antimicrobial agents (77.4% vs. 54.0%, p = 0.02) and inappropriate empirical antimicrobial therapy (22.6% vs. 3.0%, p < 0.001) were more commonly encountered in the ESBL-positive group than in the extended-spectrum cephalosporin-susceptible ESBL-negative group, respectively. Clinical outcomes did not differ significantly between the two groups (30-day mortality rate, 19.4% vs. 17.0%, p = 0.76; median length of hospital stay, 24.0 days vs. 30.5 days, p = 0.97). Initial presentation of severe sepsis/septic shock, pneumonia, and intra-abdominal infection were independently associated with 30-day mortality. The prevalence of ESBL-producing isolates was 15.3% in cancer patients with Enterobacter bacteremia. Although inappropriate empirical therapy was more common in the ESBL-positive group, ESBL production was not associated with poorer outcomes.

Cadmium and zinc sensitivity and tolerance in Klebsiella (aerobacter) aerogenes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pickett, A.W.; Dean, A.C.R.

1976-01-01

The resistance of strains of K. aerogenes NCIB 418 'trained' to Cd/sup 2 +/ or Zn/sup 2 +/ in liquid medium is graded to the training concentration. Training to Cd/sup 2 +/ increased the sensitivity to Zn/sup 2 +/ but training to Zn/sup 2 +/ reduced the sensitivity to Cd/sup 2 +/. The trained organisms, particularly those trained to Cd/sup 2 +/, grow slowly in medium containing the metals and the growth rates after 20 and 200 subcultures were not significantly different. The survival of untrained organisms on Cd/sup 2 +/ agar decreased progressively as the Cd/sup 2 +/ concentrationmore » was increased, but a threshold concentration of Zn/sup 2 +/ was necessary before any decrease set in. Very low concentrations of Zn/sup 2 +/ potentiated the lethal action of Cd/sup 2 +/ and vice versa, whereas chelating the metal ions with citrate, aspartate or gluconate eliminated it. Nutrient-limitation, as might occur in natural environments, also had a profound effect. Mg/sup 2 +/-limited organisms were particularly resistant to both metals whereas glucose-, NH/sub 4//sup +/ and PO/sub 4//sup 3 -/-limited organisms were very sensitive to Cd/sup 2 +/, and glucose- and K/sup +/-limited organisms to Zn/sup 2 +/.« less

Comparative evaluation of chromogenic agar CM1046 and mFC agar for detection of E. coli and thermotolerant coliform bacteria from water samples.

PubMed

Wohlsen, T D

2011-08-01

The equivalence of Oxoid (CM 1046) Brilliance((TM)) E. coli/coliform selective agar to mFC agar, as used in the Australian/New Zealand Standard Method to detect thermotolerant coliforms and Escherichia coli in water samples, was assessed. A total of 244 water samples were analysed in parallel over a 5-month period. Sewage effluent samples (n = 131, sites = 43), freshwater (n = 62, sites = 18) and marine/brackish water samples (n = 51, sites = 23) were analysed. The Wilcoxon matched-pairs signed-ranks test showed a varying degree of statistical difference between the two methods. All matrices had a higher recovery in the trial method. Enterococci faecalis, Aeromonas spp. and Vibrio spp. did not grow on the CM1046 agar, and Pseudomonas aeruginosa and Enterobacter aerogenes were inhibited. The use of CM 1046 for the detection and enumeration of E. coli and thermotolerant coliforms in water samples is a suitable alternative to the AS/NZS Standard Method. The use of CM1046 agar was less labour intensive and time consuming, as no secondary confirmation steps were required. Confirmed results could be reported within 24 h of sample analysis, as compared to 48 h with the reference method. Public health concerns can be addressed in a more efficient manner. © 2011 Unitywater. Letters in Applied Microbiology © 2011 The Society for Applied Microbiology.

Zero-magnetic field effect in pathogen bacteria

NASA Astrophysics Data System (ADS)

Creanga, D. E.; Poiata, A.; Morariu, V. V.; Tupu, P.

2004-05-01

Two lots of Gram-negative bacterial strains were tested for antibiotic drug resistance after exposure to zero-magnetic field. We found that the magneto-sensitive strains represent half of the analyzed samples (three Pseudomonas and five Enterobacter strains), some of them presenting two-three times modified resistance to antibiotic, while others revealed eight or 16 times changed resistance. Pseudomonas strain magnetic sensitivity is revealed better by ampicillin and tetracycline, while Enterobacter strain magnetic sensitivity is revealed better by ampicillin, kanamycin and ofloxacin.

Specificity of the high-mannose recognition site between Enterobacter cloacae pili adhesin and HT-29 cell membranes.

PubMed Central

Pan, Y T; Xu, B; Rice, K; Smith, S; Jackson, R; Elbein, A D

1997-01-01

Enterobacter cloacae has been implicated as one of the causative agents in neonatal infection and causes a septicemia thought to be initiated via the gastrointestinal tract. The adhesion of radiolabeled E. cloacae to HT-29 cells was concentration and temperature dependent and was effectively blocked by unlabeled bacteria or by millimolar concentrations of alpha-mannosides and micromolar concentrations of high-mannose oligosaccharides. A variety of well-characterized mannose oligosaccharides were tested as inhibitors of adhesion. The best inhibitor was the Man9(GlcNAc)2-tyrosinamide, which was considerably better than other tyrosinamide-linked oligosaccharides such as Man7(GlcNAc)2, Man6(GlcNAc)2 or Man5(GlcNAc)2. Further evidence that the bacteria preferred Man9(GlcNAc)2 structures was obtained by growing HT-29 cells in the presence of glycoprotein processing inhibitors that block mannosidase I and increase the amount of protein-bound Man9(GlcNAc)2 at the cell surface. Such cells bound 1.5- to 2-fold more bacteria than did control cells. The adhesin involved in binding to high-mannose structures was purified from isolated pili. On sodium dodecyl sulfate-gels, a 35-kDa protein was identified by its specific binding to a mannose-containing biotinylated albumin. The amino acid sequences of several peptides from the 35-kDa subunit showed over 85% identity to FimH, the mannose-specific adhesin of Salmonella typhimurium. Pili were labeled with 125I and examined for the ability to bind to HT-29 cells. Binding showed saturation kinetics and was inhibited by the addition of Man9(GlcNAc)2-tyrosinamide but not by oligosaccharides with fewer mannose residues. Polyclonal antibody against this 35-kDa protein also effectively blocked adhesion of pili or E. cloacae, but no effect was observed with nonspecific antibody. These studies demonstrate that the 35-kDa pilus subunit is a lectin whose specificity is directed toward Man, (GlcNAc)2 oligosaccharides. PMID:9317027

Effect of white mustard essential oil on the growth of foodborne pathogens and spoilage microorganisms and the effect of food components on its efficacy.

PubMed

Monu, Emefa A; David, Jairus R D; Schmidt, Marcel; Davidson, P Michael

2014-12-01

Antimicrobial preservative compounds are added to foods to target specific pathogens and spoilage organisms. White mustard essential oil (WMEO) is an extract that contains 4-hydroxybenzyl isothiocyanate, a compound which has been demonstrated to have antimicrobial activity in limited studies. The objective of this research was to determine the in vitro antimicrobial activity of WMEO against gram-positive and gram-negative spoilage and pathogenic bacteria and determine the effect of food components on the antimicrobial activity. The bacteria Escherichia coli, Salmonella enterica serovar Enteritidis, Enterobacter aerogenes, Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, and Lactobacillus fermentum, as well as the acid- and preservative-resistant yeast Schizosaccharomyces pombe, were evaluated. All microorganisms were inhibited by WMEO at 8.3 g/liter (equivalent to 1,000 mg/liter 4-hydroxybenzyl isothiocyanate). In general, WMEO was more effective against gram-negative than against gram-positive bacteria. Salmonella Enteritidis and S. pombe were the most sensitive, with inhibition at as low as 2.1 g/liter. The effects on growth profiles varied but included increased lag phases and lethality, indicating both bacteriostatic and bactericidal activity. Soybean oil had a negative effect on the efficacy of WMEO against L. monocytogenes, and at 5% soybean oil, the antimicrobial activity against Salmonella Enteritidis was eliminated after 48 h. Sodium caseinate at 1% also negated the antimicrobial effect of WMEO against Salmonella Enteritidis and decreased its effectiveness against L. monocytogenes. The presence of starch had no significant effect on the antimicrobial activity of WMEO against L. monocytogenes and Salmonella Enteritidis. Thus, WMEO is effective against a wide range of microorganisms and has potential to be used in foods, depending upon the target microorganism and food components present.

Decreasing Enterobacter sakazakii (Cronobacter spp.) food contamination level with bacteriophages: prospects and problems

PubMed Central

Zuber, Sophie; Boissin‐Delaporte, Catherine; Michot, Lise; Iversen, Carol; Diep, Benjamin; Brüssow, Harald; Breeuwer, Pieter

2008-01-01

Summary Enterobacter sakazakii (Cronobacter spp.) is an opportunistic pathogen, which can cause rare, but life‐threatening infections in neonates and infants through feeding of a contaminated milk formula. We isolated 67 phages from environmental samples and tested their lytic host range on a representative collection of 40 E. sakazakii strains. A cocktail of five phages prevented the outgrowth of 35 out of 40 test strains in artificially contaminated infant formula. Two E. sakazakii phages represented prolate head Myoviridae. Molecular tests identified them as close relatives of Escherichia coli phage T4. The remaining three phages represented isometric head Myoviridae with large genome size of 140 and 200 kb, respectively, which belonged to two different DNA hybridization groups. A high dose of 108 pfu ml−1 of phage could effectively sterilize a broth contaminated with both high and low pathogen counts (106 and 102 cfu ml−1). In contrast, broth inoculated with 104 phage and 102 bacteria per ml first showed normal bacterial growth until reaching a cell titre of 105 cfu ml−1. Only when crossing this threshold, phage replication started, but it could not reduce the contamination level below 100 cfu ml−1. Phages could be produced with titres of 1010 pfu ml−1 in broth culture, but they were not stable upon freeze‐drying. Addition of trehalose or milk formula stabilized the phage preparation, which then showed excellent storage stability even at elevated temperature. PMID:21261874

Use of bile-esculin agar for rapid differentiation of Enterobacteriaceae.

PubMed Central

Lindell, S S; Quinn, P

1975-01-01

Bile-esculin agar has been used for several years for the presumptive identification of group D streptococci. All members of the Enterobacteriaceae family will also grow on this medium, but only certain ones can hydrolyze esculin to 6,7-dihydroxycoumarin, which reacts with iron to produce a characteristic blackening of the medium. One thousand and six cultures from clinical specimens representing 20 genera were isolated and identified. Heavy inocula from fresh pure culture isolates on heart infusion agar were placed on bile-esculin agar slants and incubated at 35 C. The slants were examined at 4 h and again at 18 h for esculin hydrolysis. Shigella, Salmonella, Arizona, Proteus mirabilis, Proteus morganii, Providencia alcalifaciens, and Providencia stuartii all produced negative results. Klebsiella pneumoniae, Enterobacter aerogenes, Serratia marcescens, and Serratia rubidaea produced a positive reaction in 4 h. The other remaining eight genera exhibited varying results. The use of this medium in conjunction with triple sugar iron-lysine iron agar has been of great value in differentiating the Klebsiella-Enterobacter-Serratia group from other Enterobacteriaceae. PMID:1176613

Presence of antimicrobial resistance in coliform bacteria from hatching broiler eggs with emphasis on ESBL/AmpC-producing bacteria.

PubMed

Mezhoud, H; Chantziaras, I; Iguer-Ouada, M; Moula, N; Garmyn, A; Martel, A; Touati, A; Smet, A; Haesebrouck, F; Boyen, F

2016-08-01

Antimicrobial resistance is recognized as one of the most important global health challenges. Broilers are an important reservoir of antimicrobial resistant bacteria in general and, more particularly, extended-spectrum β-lactamases (ESBL)/AmpC-producing Enterobacteriaceae. Since contamination of 1-day-old chicks is a potential risk factor for the introduction of antimicrobial resistant Enterobacteriaceae in the broiler production chain, the presence of antimicrobial resistant coliform bacteria in broiler hatching eggs was explored in the present study. Samples from 186 hatching eggs, collected from 11 broiler breeder farms, were inoculated on MacConkey agar with or without ceftiofur and investigated for the presence of antimicrobial resistant lactose-positive Enterobacteriaceae, particularly, ESBL/AmpC-producers. Escherichia coli and Enterobacter cloacae were obtained from the eggshells in 10 out of 11 (10/11) sampled farms. The majority of the isolates were recovered from crushed eggshells after external decontamination suggesting that these bacteria are concealed from the disinfectants in the egg shell pores. Antimicrobial resistance testing revealed that approximately 30% of the isolates showed resistance to ampicillin, tetracycline, trimethoprim and sulphonamides, while the majority of isolates were susceptible to amoxicillin-clavulanic acid, nitrofurantoin, aminoglycosides, florfenicol, neomycin and apramycin. Resistance to extended-spectrum cephalosporins was detected in eight Enterobacteriaceae isolates from five different broiler breeder farms. The ESBL phenotype was confirmed by the double disk synergy test and blaSHV-12, blaTEM-52 and blaACT-39 resistance genes were detected by PCR. This report is the first to present broiler hatching eggs as carriers and a potential source of ESBL/AmpC-producing Enterobacteriaceae for broiler chicks.

Discrimination of selected species of pathogenic bacteria using near-infrared Raman spectroscopy and principal components analysis

NASA Astrophysics Data System (ADS)

de Siqueira e Oliveira, Fernanda SantAna; Giana, Hector Enrique; Silveira, Landulfo

2012-10-01

A method, based on Raman spectroscopy, for identification of different microorganisms involved in bacterial urinary tract infections has been proposed. Spectra were collected from different bacterial colonies (Gram-negative: Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa and Enterobacter cloacae, and Gram-positive: Staphylococcus aureus and Enterococcus spp.), grown on culture medium (agar), using a Raman spectrometer with a fiber Raman probe (830 nm). Colonies were scraped from the agar surface and placed on an aluminum foil for Raman measurements. After preprocessing, spectra were submitted to a principal component analysis and Mahalanobis distance (PCA/MD) discrimination algorithm. We found that the mean Raman spectra of different bacterial species show similar bands, and S. aureus was well characterized by strong bands related to carotenoids. PCA/MD could discriminate Gram-positive bacteria with sensitivity and specificity of 100% and Gram-negative bacteria with sensitivity ranging from 58 to 88% and specificity ranging from 87% to 99%.

Antimicrobial, wound healing and antioxidant activity of Plagiochasma appendiculatum Lehm. et Lind.

PubMed

Singh, Meenakshi; Govindarajan, Raghavan; Nath, Virendra; Rawat, Ajay Kumar Singh; Mehrotra, Shanta

2006-08-11

Plagiochasma appendiculatum (Aytoniaceae) of the order Marchantiales is widely used in the form of paste ethnomedicinally by Gaddi tribe in Kangra valley for treating skin diseases. In this context, antimicrobical potential of Plagiochasma appendiculatum against a wide range of microorganisms was studied. To validate the ethnotherapeutic claims of the plant in skin diseases, wound healing activity was studied, besides antioxidant activity to understand the mechanism of wound healing activity. The plant (alchoholic and aqueous extract) showed significant antibacterial and antifungal activity against almost all the organisms: Micrococcus luteus, Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, Streptococcus pneumoniae, Enterobacter aerogenes, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Salmonella typhimurium, and eight fungi Candida albicans and Cryptococcus albidus-dimorphic fungi, Trichophyton rubrum-dermatophyte fungi, Aspergillus niger, Aspergillus flavus, Aspergillus spinulosus, Aspergillus terreus and Aspergillus nidulans-systemic fungi, with especially good activity against the dermatophyte (Trichophyton rubrum) and some infectious bacteria (Escherichia coli, Proteus mirabilis and Salmonella typhimurium) with an MIC of 2.5 microg/disc. The results show that Plagiochasma appendiculatum extract has potent wound healing capacity as evident from the wound contraction and increased tensile strength. The results also indicated that Plagiochasma appendiculatum extract possesses potent antioxidant activity by inhibiting lipid peroxidation and increase in the superoxide dismutase (SOD) and Catalase activity.

Jacaranda cuspidifolia Mart. (Bignoniaceae) as an antibacterial agent.

PubMed

Arruda, Ana Lúcia A; Vieira, Carla J B; Sousa, Daniella G; Oliveira, Regilene F; Castilho, Rachel O

2011-12-01

This study evaluated, in vitro, the antimicrobial activity of the hexane extract (JCHE), methanol extract (JCME), and chloroform fraction (JCCF) of bark from Jacaranda cuspidifolia Mart. (Family Bignoniaceae), a Brazilian medicinal plant, traditionally used as anti-syphilis and anti-gonorrhea treatment. The antimicrobial activity was evaluated using the disc diffusion method followed by the determination of minimum inhibitory concentration (MIC) values. JCHE was not active against the bacteria evaluated. JCME presented antibacterial activity against Streptococcus pyogenes, Staphylococcus aureus, and Neisseria gonorrhoeae with MIC values of 16.3 mg/mL, 9.1 mg/mL, and 25.2 mg/mL, respectively. JCCF was active against Staphylococcus epidermidis, S. aureus, Proteus mirabilis, Serratia marcescens, S. pyogenes, Enterobacter aerogenes, and N. gonorrhoeae with MIC values of 18.3 mg/mL, 9.3 mg/mL, 6.3 mg/mL, 6.1 mg/mL, 9.2 mg/mL, 6.2 mg/mL, and 25.2 mg/mL, respectively. Phytochemical analysis of JCME and JCCF gave positive results for saponins, coumarins, flavonoids, tannins, quinones, alkaloids, triterpenes, and steroids. Verbascoside was isolated and identified as a major peak in JCME and JCCF high-performance liquid chromatography fingerprints and might contribute to the observed antimicrobial activity.

Synthesis, characterization and molecular weight monitoring of a novel Schiff base polymer containing phenol group: Thermal stability, conductivity and antimicrobial properties

NASA Astrophysics Data System (ADS)

Yılmaz Baran, Nuray; Saçak, Mehmet

2017-10-01

A novel Schiff base polymer containing phenol group, Poly(3-[[4-(dimethylamino)benzylidene]amino]phenol) P(3-DBAP), was prepared by oxidative polycondensation reaction of 3-[[4-(dimethylamino)benzylidene]amino]phenol (3-DBAP) using NaOCl, H2O2, O2 oxidants in aqueous alkaline medium. Yield and molecular weight distribution of P(3-DBAP) were monitored depending on oxidant types and concentration, monomer concentration and as well as polymerization temperature and time. UV-Vis, FTIR and 1HNMR techniques were used to identify the structures of Schiff base monomer and polymer. Thermal behavior of P(3-DBAP), which was determined to be thermally stable up to 1200 °C via TG-DTG techniques, was illuminated by Thermo-IR spectra recorded in the temperature range of 25-800 °C. It was determined that the electrical conductivity value of the P(3-DBAP) increased 108 fold after doped with iodine for 24 h at 60 °C according to undoped form and it was measured 4.6 × 10-4 S/cm. Also, antibacterial and antifungal activities of the monomer and polymer were assayed against Sarcina lutea, Enterobacter aerogenes, Escherichia coli, Enterococcus Feacalis, Klebsiella pneumoniae, Bacillus subtilis bacteria, and Candida albicans, Saccharomyces cerevisiae fungi.

Phylogenetic Network Analysis Revealed the Occurrence of Horizontal Gene Transfer of 16S rRNA in the Genus Enterobacter

PubMed Central

Sato, Mitsuharu; Miyazaki, Kentaro

2017-01-01

Horizontal gene transfer (HGT) is a ubiquitous genetic event in bacterial evolution, but it seldom occurs for genes involved in highly complex supramolecules (or biosystems), which consist of many gene products. The ribosome is one such supramolecule, but several bacteria harbor dissimilar and/or chimeric 16S rRNAs in their genomes, suggesting the occurrence of HGT of this gene. However, we know little about whether the genes actually experience HGT and, if so, the frequency of such a transfer. This is primarily because the methods currently employed for phylogenetic analysis (e.g., neighbor-joining, maximum likelihood, and maximum parsimony) of 16S rRNA genes assume point mutation-driven tree-shape evolution as an evolutionary model, which is intrinsically inappropriate to decipher the evolutionary history for genes driven by recombination. To address this issue, we applied a phylogenetic network analysis, which has been used previously for detection of genetic recombination in homologous alleles, to the 16S rRNA gene. We focused on the genus Enterobacter, whose phylogenetic relationships inferred by multi-locus sequence alignment analysis and 16S rRNA sequences are incompatible. All 10 complete genomic sequences were retrieved from the NCBI database, in which 71 16S rRNA genes were included. Neighbor-joining analysis demonstrated that the genes residing in the same genomes clustered, indicating the occurrence of intragenomic recombination. However, as suggested by the low bootstrap values, evolutionary relationships between the clusters were uncertain. We then applied phylogenetic network analysis to representative sequences from each cluster. We found three ancestral 16S rRNA groups; the others were likely created through recursive recombination between the ancestors and chimeric descendants. Despite the large sequence changes caused by the recombination events, the RNA secondary structures were conserved. Successive intergenomic and intragenomic recombination

Hybrid modeling of microbial exopolysaccharide (EPS) production: The case of Enterobacter A47.

PubMed

Marques, Rodolfo; von Stosch, Moritz; Portela, Rui M C; Torres, Cristiana A V; Antunes, Sílvia; Freitas, Filomena; Reis, Maria A M; Oliveira, Rui

2017-03-20

Enterobacter A47 is a bacterium that produces high amounts of a fucose-rich exopolysaccharide (EPS) from glycerol residue of the biodiesel industry. The fed-batch process is characterized by complex non-linear dynamics with highly viscous pseudo-plastic rheology due to the accumulation of EPS in the culture medium. In this paper, we study hybrid modeling as a methodology to increase the predictive power of models for EPS production optimization. We compare six hybrid structures that explore different levels of knowledge-based and machine-learning model components. Knowledge-based components consist of macroscopic material balances, Monod type kinetics, cardinal temperature and pH (CTP) dependency and power-law viscosity models. Unknown dependencies are set to be identified by a feedforward artificial neural network (ANN). A semiparametric identification schema is applied resorting to a data set of 13 independent fed-batch experiments. A parsimonious hybrid model was identified that describes the dynamics of the 13 experiments with the same parameterization. The final model is specific to Enterobacter A47 but can be easily extended to other microbial EPS processes. Copyright © 2017 Elsevier B.V. All rights reserved.

Mercury bioremediation by mercury accumulating Enterobacter sp. cells and its alginate immobilized application.

PubMed

Sinha, Arvind; Khare, Sunil Kumar

2012-02-01

The effective microbial remediation of the mercury necessitates the mercury to be trapped within the cells without being recycled back to the environment. The study describes a mercury bioaccumulating strain of Enterobacter sp., which remediated mercury from the medium simultaneous to its growth. The transmission electron micrographs and electron dispersive X-ray analysis revealed the accumulation of remediated mercury as nano-size particles in the cytoplasm as well as on the cell wall. The Enterobacter sp. in the present work was able to accumulate mercury, without being engineered in its native form. The possibility of recovering the accumulated mercury from the cells is also indicated. The applicability of the alginate immobilized cells in removing mercury from synthetic and complex industrial effluent in a batch mode was amply demonstrated. The initial load of 7.3 mg l(-1) mercury in the industrial effluent was completely removed in 72 h. The cells immobilized in calcium alginate were similarly effective in the complete removal of 5 mg l(-1) HgCl(2) of mercury from the synthetic effluent in less than 72 h. The immobilized cells could be reused for multiple cycles.

Occurrence of Enterobacter hormaechei carrying blaNDM-1 and blaKPC-2 in China.

PubMed

Yang, Biwei; Feng, Yu; McNally, Alan; Zong, Zhiyong

2018-02-01

Three carbapenem-resistant clinical isolates of the Enterobacter cloacae complex (ECC) were recovered from different patients in a hospital. All 3 isolates carried 2 carbapenemase genes bla KPC-2 and bla NDM-1 . A study was performed to characterize their relatedness and to investigate possible links among the patients. Whole genome sequencing revealed that the isolates were Enterobacter hormaechei and belonged to ST177 of the ECC. There were 19-142 single nucleotide polymorphisms (SNPs) between the isolates, suggesting that the isolates were likely from a central reservoir, which might have existed for some time. bla KPC-2 and bla NDM-1 were carried on 2 different IncF-type plasmids in the isolates. The 3 bla NDM-1 -carrying plasmids were almost identical and were self-transmissible, while the bla KPC-2 -carrying plasmids were only transmissible in the presence of the bla NDM-1 -carrying plasmid. The source of and direct links among them were not identified, suggesting a hospital transmission of a common multidrug resistant strain. Copyright © 2017 Elsevier Inc. All rights reserved.

Transcriptional Responses to Sucrose Mimic the Plant-Associated Life Style of the Plant Growth Promoting Endophyte Enterobacter sp. 638

DOE PAGES

Taghavi, Safiyh; Wu, Xiao; Ouyang, Liming; ...

2015-01-21

Growth in sucrose medium was previously found to trigger the expression of functions involved in the plant associated life style of the endophytic bacterium Enterobacter sp. 638. Therefore, comparative transcriptome analysis between cultures grown in sucrose or lactate medium was used to gain insights in the expression levels of bacterial functions involved in the endophytic life style of strain 638. Growth on sucrose as a carbon source resulted in major changes in cell physiology, including a shift from a planktonic life style to the formation of bacterial aggregates. This shift was accompanied by a decrease in transcription of genes involvedmore » in motility (e.g. flagella biosynthesis) and an increase in the transcription of genes involved in colonization, adhesion and biofilm formation. The transcription levels of functions previously suggested as being involved in endophytic behavior and functions responsible for plant growth promoting properties, including the synthesis of indole-acetic acid, acetoin and 2,3-butanediol, also increased significantly for cultures grown in sucrose medium. Interestingly, despite an abundance of essential nutrients transcription levels of functions related to uptake and processing of nitrogen and iron became increased for cultures grown on sucrose as sole carbon source. Transcriptome data were also used to analyze putative regulatory relationships. In addition to the small RNA csrABCD regulon, which seems to play a role in the physiological adaptation and possibly the shift between free-living and plant-associated endophytic life style of Enterobacter sp. 638, our results also pointed to the involvement of rcsAB in controlling responses by Enterobacter sp. 638 to a plant-associated life style. Lastly, targeted mutagenesis was used to confirm this role and showed that compared to wild-type Enterobacter sp. 638 a ΔrcsB mutant was affected in its plant growth promoting ability.« less

Transcriptional Responses to Sucrose Mimic the Plant-Associated Life Style of the Plant Growth Promoting Endophyte Enterobacter sp. 638

PubMed Central

Taghavi, Safiyh; Wu, Xiao; Ouyang, Liming; Stadler, Andrea; McCorkle, Sean; Zhu, Wei; Maslov, Sergei; van der Lelie, Daniel

2015-01-01

Growth in sucrose medium was previously found to trigger the expression of functions involved in the plant associated life style of the endophytic bacterium Enterobacter sp. 638. Therefore, comparative transcriptome analysis between cultures grown in sucrose or lactate medium was used to gain insights in the expression levels of bacterial functions involved in the endophytic life style of strain 638. Growth on sucrose as a carbon source resulted in major changes in cell physiology, including a shift from a planktonic life style to the formation of bacterial aggregates. This shift was accompanied by a decrease in transcription of genes involved in motility (e.g. flagella biosynthesis) and an increase in the transcription of genes involved in colonization, adhesion and biofilm formation. The transcription levels of functions previously suggested as being involved in endophytic behavior and functions responsible for plant growth promoting properties, including the synthesis of indole-acetic acid, acetoin and 2,3-butanediol, also increased significantly for cultures grown in sucrose medium. Interestingly, despite an abundance of essential nutrients transcription levels of functions related to uptake and processing of nitrogen and iron became increased for cultures grown on sucrose as sole carbon source. Transcriptome data were also used to analyze putative regulatory relationships. In addition to the small RNA csrABCD regulon, which seems to play a role in the physiological adaptation and possibly the shift between free-living and plant-associated endophytic life style of Enterobacter sp. 638, our results also pointed to the involvement of rcsAB in controlling responses by Enterobacter sp. 638 to a plant-associated life style. Targeted mutagenesis was used to confirm this role and showed that compared to wild-type Enterobacter sp. 638 a ΔrcsB mutant was affected in its plant growth promoting ability. PMID:25607953

Transcriptional responses to sucrose mimic the plant-associated life style of the plant growth promoting endophyte Enterobacter sp. 638.

PubMed

Taghavi, Safiyh; Wu, Xiao; Ouyang, Liming; Zhang, Yian Biao; Stadler, Andrea; McCorkle, Sean; Zhu, Wei; Maslov, Sergei; van der Lelie, Daniel

2015-01-01

Growth in sucrose medium was previously found to trigger the expression of functions involved in the plant associated life style of the endophytic bacterium Enterobacter sp. 638. Therefore, comparative transcriptome analysis between cultures grown in sucrose or lactate medium was used to gain insights in the expression levels of bacterial functions involved in the endophytic life style of strain 638. Growth on sucrose as a carbon source resulted in major changes in cell physiology, including a shift from a planktonic life style to the formation of bacterial aggregates. This shift was accompanied by a decrease in transcription of genes involved in motility (e.g., flagella biosynthesis) and an increase in the transcription of genes involved in colonization, adhesion and biofilm formation. The transcription levels of functions previously suggested as being involved in endophytic behavior and functions responsible for plant growth promoting properties, including the synthesis of indole-acetic acid, acetoin and 2,3-butanediol, also increased significantly for cultures grown in sucrose medium. Interestingly, despite an abundance of essential nutrients transcription levels of functions related to uptake and processing of nitrogen and iron became increased for cultures grown on sucrose as sole carbon source. Transcriptome data were also used to analyze putative regulatory relationships. In addition to the small RNA csrABCD regulon, which seems to play a role in the physiological adaptation and possibly the shift between free-living and plant-associated endophytic life style of Enterobacter sp. 638, our results also pointed to the involvement of rcsAB in controlling responses by Enterobacter sp. 638 to a plant-associated life style. Targeted mutagenesis was used to confirm this role and showed that compared to wild-type Enterobacter sp. 638 a ΔrcsB mutant was affected in its plant growth promoting ability.

Transcriptional Responses to Sucrose Mimic the Plant-Associated Life Style of the Plant Growth Promoting Endophyte Enterobacter sp. 638

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taghavi, Safiyh; Wu, Xiao; Ouyang, Liming

Growth in sucrose medium was previously found to trigger the expression of functions involved in the plant associated life style of the endophytic bacterium Enterobacter sp. 638. Therefore, comparative transcriptome analysis between cultures grown in sucrose or lactate medium was used to gain insights in the expression levels of bacterial functions involved in the endophytic life style of strain 638. Growth on sucrose as a carbon source resulted in major changes in cell physiology, including a shift from a planktonic life style to the formation of bacterial aggregates. This shift was accompanied by a decrease in transcription of genes involvedmore » in motility (e.g. flagella biosynthesis) and an increase in the transcription of genes involved in colonization, adhesion and biofilm formation. The transcription levels of functions previously suggested as being involved in endophytic behavior and functions responsible for plant growth promoting properties, including the synthesis of indole-acetic acid, acetoin and 2,3-butanediol, also increased significantly for cultures grown in sucrose medium. Interestingly, despite an abundance of essential nutrients transcription levels of functions related to uptake and processing of nitrogen and iron became increased for cultures grown on sucrose as sole carbon source. Transcriptome data were also used to analyze putative regulatory relationships. In addition to the small RNA csrABCD regulon, which seems to play a role in the physiological adaptation and possibly the shift between free-living and plant-associated endophytic life style of Enterobacter sp. 638, our results also pointed to the involvement of rcsAB in controlling responses by Enterobacter sp. 638 to a plant-associated life style. Lastly, targeted mutagenesis was used to confirm this role and showed that compared to wild-type Enterobacter sp. 638 a ΔrcsB mutant was affected in its plant growth promoting ability.« less

[The importance of endotoxin producing bacterias for practical purposes

PubMed

Schimmel, Dietrich

1994-01-01

Lipopolysaccharides (endotoxin) cause according to resorption out of the intestinal tract or aerogenic inhalation or by a septic infection clinical signs. The clinical reactions are praeshock symptoms, acute forms of shock and death. The experimental intratracheally administration of lipopolysaccharides into calves caused pneumonic lesions without bacterial experimental infection.

Alleviation of salt stress by enterobacter sp. EJ01 in tomato and Arabidopsis is accompanied by up-regulation of conserved salinity responsive factors in plants.

PubMed

Kim, Kangmin; Jang, Ye-Jin; Lee, Sang-Myeong; Oh, Byung-Taek; Chae, Jong-Chan; Lee, Kui-Jae

2014-02-01

Microbiota in the niches of the rhizosphere zones can affect plant growth and responses to environmental stress conditions via mutualistic interactions with host plants. Specifically, some beneficial bacteria, collectively referred to as Plant Growth Promoting Rhizobacteria (PGPRs), increase plant biomass and innate immunity potential. Here, we report that Enterobacter sp. EJ01, a bacterium isolated from sea china pink (Dianthus japonicus thunb) in reclaimed land of Gyehwa-do in Korea, improved the vegetative growth and alleviated salt stress in tomato and Arabidopsis. EJ01 was capable of producing 1-aminocy-clopropane-1-carboxylate (ACC) deaminase and also exhibited indole-3-acetic acid (IAA) production. The isolate EJ01 conferred increases in fresh weight, dry weight, and plant height of tomato and Arabidopsis under both normal and high salinity conditions. At the molecular level, short-term treatment with EJ01 increased the expression of salt stress responsive genes such as DREB2b, RD29A, RD29B, and RAB18 in Arabidopsis. The expression of proline biosynthetic genes (i.e. P5CS1 and P5CS2) and of genes related to priming processes (i.e. MPK3 and MPK6) were also up-regulated. In addition, reactive oxygen species scavenging activities were enhanced in tomatoes treated with EJ01 in stressed conditions. GFP-tagged EJ01 displayed colonization in the rhizosphere and endosphere in the roots of Arabidopsis. In conclusion, the newly isolated Enterobacter sp. EJ01 is a likely PGPR and alleviates salt stress in host plants through multiple mechanisms, including the rapid up-regulation of conserved plant salt stress responsive signaling pathways.

Alleviation of Salt Stress by Enterobacter sp. EJ01 in Tomato and Arabidopsis Is Accompanied by Up-Regulation of Conserved Salinity Responsive Factors in Plants

PubMed Central

Kim, Kangmin; Jang, Ye-Jin; Lee, Sang-Myeong; Oh, Byung-Taek; Chae, Jong-Chan; Lee, Kui-Jae

2014-01-01

Microbiota in the niches of the rhizosphere zones can affect plant growth and responses to environmental stress conditions via mutualistic interactions with host plants. Specifically, some beneficial bacteria, collectively referred to as Plant Growth Promoting Rhizobacteria (PGPRs), increase plant biomass and innate immunity potential. Here, we report that Enterobacter sp. EJ01, a bacterium isolated from sea china pink (Dianthus japonicus thunb) in reclaimed land of Gyehwa-do in Korea, improved the vegetative growth and alleviated salt stress in tomato and Arabidopsis. EJ01 was capable of producing 1-aminocy-clopropane-1-carboxylate (ACC) deaminase and also exhibited indole-3-acetic acid (IAA) production. The isolate EJ01 conferred increases in fresh weight, dry weight, and plant height of tomato and Arabidopsis under both normal and high salinity conditions. At the molecular level, short-term treatment with EJ01 increased the expression of salt stress responsive genes such as DREB2b, RD29A, RD29B, and RAB18 in Arabidopsis. The expression of proline biosynthetic genes (i.e. P5CS1 and P5CS2) and of genes related to priming processes (i.e. MPK3 and MPK6) were also up-regulated. In addition, reactive oxygen species scavenging activities were enhanced in tomatoes treated with EJ01 in stressed conditions. GFP-tagged EJ01 displayed colonization in the rhizosphere and endosphere in the roots of Arabidopsis. In conclusion, the newly isolated Enterobacter sp. EJ01 is a likely PGPR and alleviates salt stress in host plants through multiple mechanisms, including the rapid up-regulation of conserved plant salt stress responsive signaling pathways. PMID:24598995

Aerogenic vaccination with a Burkholderia mallei auxotroph protects against aerosol-initiated glanders in mice.

PubMed

Ulrich, Ricky L; Amemiya, Kei; Waag, David M; Roy, Chad J; DeShazer, David

2005-03-14

Burkholderia mallei is an obligate mammalian pathogen that causes the zoonotic disease glanders. Two live attenuated B. mallei strains, a capsule mutant and a branched-chain amino acid auxotroph, were evaluated for use as vaccines against aerosol-initiated glanders in mice. Animals were aerogenically vaccinated and serum samples were obtained before aerosol challenge with a high-dose (>300 times the LD50) of B. mallei ATCC 23344. Mice vaccinated with the capsule mutant developed a Th2-like Ig subclass antibody response and none survived beyond 5 days. In comparison, the auxotrophic mutant elicited a Th1-like Ig subclass antibody response and 25% of the animals survived for 1 month postchallenge. After a low-dose (5 times the LD50) aerosol challenge, the survival rates of auxotroph-vaccinated and unvaccinated animals were 50 and 0%, respectively. Thus, live attenuated strains that promote a Th1-like Ig response may serve as promising vaccine candidates against aerosol infection with B. mallei.

Temperature and pH effect on glucose production from pretreated bagasse by a novel species of Citrobacter and other bacteria.

PubMed

Jones, Jamila A D; Kerr, R G; Haltli, B A; Tinto, Winston F

2018-06-01

Cellulolytic bacteria that produce cellulases, which are active over a range of pH and temperatures, can be used to catalyze hydrolysis of pretreated lignocellulosic material. This is important in the production of second generation biofuels among other biotechnological applications. In this investigation, bacteria isolated from sugarcane bagasse were identified as strains of Enterobacter xiangfangensis , Serratia rubidaea , Klebsiella pneumoniae and a novel species of Citrobacter designated Citrobacter sp. UWIBGS10. The glucose production potential of these strains was studied on thermally and solvent pretreated sugarcane bagasse. This was performed at 24-hour intervals up to 168 hours in the range of pH 5-9 and temperature range 25-40 °C. Maximal concentrations of glucose for Citrobacter sp. UWIBGS10 occurred at pH 6 and 25 °C. For E. xiangfangensis , S. rubidaea , K. pneumoniae glucose concentrations were consistent across the pH and temperature ranges examined. From these results it could be concluded that the bacteria demonstrated ability for lignocellulolytic hydrolysis for the production of glucose and could be further explored for the characterization of commercial cellulolytic enzymes.

Occurrence of bacteriophages infecting Aeromonas, Enterobacter, and Klebsiella in water and association with contamination sources in Thailand.

PubMed

Wangkahad, Bencharong; Bosup, Suchada; Mongkolsuk, Skorn; Sirikanchana, Kwanrawee

2015-06-01

The co-residence of bacteriophages and their bacterial hosts in humans, animals, and environmental sources directed the use of bacteriophages to track the origins of the pathogenic bacteria that can be found in contaminated water. The objective of this study was to enumerate bacteriophages of Aeromonas caviae (AecaKS148), Enterobacter sp. (EnspKS513), and Klebsiella pneumoniae (KlpnKS648) in water and evaluate their association with contamination sources (human vs. animals). Bacterial host strains were isolated from untreated wastewater in Bangkok, Thailand. A double-layer agar technique was used to detect bacteriophages. All three bacteriophages were detected in polluted canal samples, with likely contamination from human wastewater, whereas none was found in non-polluted river samples. AecaKS148 was found to be associated with human fecal sources, while EnspKS513 and KlpnKS648 seemed to be equally prevalent in both human and animal fecal sources. Both bacteriophages were also present in polluted canals that could receive contamination from other fecal sources or the environment. In conclusion, all three bacteriophages were successfully monitored in Bangkok, Thailand. This study provided an example of bacteriophages for potential use as source identifiers of pathogen contamination. The results from this study will assist in controlling sources of pathogen contamination, especially in developing countries.

Cultivable endophytic bacteria from leaf bases of Agave tequilana and their role as plant growth promoters

PubMed Central

Martínez-Rodríguez, Julia del C.; la Mora-Amutio, Marcela De; Plascencia-Correa, Luis A.; Audelo-Regalado, Esmeralda; Guardado, Francisco R.; Hernández-Sánchez, Elías; Peña-Ramírez, Yuri J.; Escalante, Adelfo; Beltrán-García, Miguel J.; Ogura, Tetsuya

2014-01-01

Agave tequilana Weber var. ‘Azul’ is grown for the production of tequila, inulin and syrup. Diverse bacteria inhabit plant tissues and play a crucial role for plant health and growth. In this study culturable endophytic bacteria were extracted from leaf bases of 100 healthy Agave tequilana plants. In plant tissue bacteria occurred at mean population densities of 3 million CFU/g of fresh plant tissue. Three hundred endophytic strains were isolated and 16s rDNA sequences grouped the bacteria into eight different taxa that shared high homology with other known sequences. Bacterial endophytes were identified as Acinectobacter sp., A. baumanii, A. bereziniae, Cronobacter sakazakii, Enterobacter hormaechei, Bacillus sp. Klebsiella oxytoca, Pseudomonas sp., Enterococcus casseliflavus, Leuconostoc mesenteroides subsp. mesenteroides and Gluconobacter oxydans. Isolates were confirmed to be plant growth promoting bacteria (PGPB) by their capacities for nitrogen fixation, auxin production, phosphate solubilization, or antagonism against Fusarium oxysporum AC132. E. casseliflavus JM47 and K. oxytoca JM26 secreted the highest concentrations of IAA. The endophyte Acinectobacter sp. JM58 exhibited the maximum values for nitrogen fixation and phosphate solubilization index (PSI). Inhibition of fungi was found in Pseudomonas sp. JM9p and K. oxytoca JM26. Bacterial endophytes show promise for use as bio-inoculants for agave cultivation. Use of endophytes to enhance cultivation of agave may be particularly important for plants produced by micropropagation techniques, where native endophytes may have been lost. PMID:25763038

Cultivable endophytic bacteria from leaf bases of Agave tequilana and their role as plant growth promoters.

PubMed

Martínez-Rodríguez, Julia del C; De la Mora-Amutio, Marcela; Plascencia-Correa, Luis A; Audelo-Regalado, Esmeralda; Guardado, Francisco R; Hernández-Sánchez, Elías; Peña-Ramírez, Yuri J; Escalante, Adelfo; Beltrán-García, Miguel J; Ogura, Tetsuya

2014-01-01

Agave tequilana Weber var. 'Azul' is grown for the production of tequila, inulin and syrup. Diverse bacteria inhabit plant tissues and play a crucial role for plant health and growth. In this study culturable endophytic bacteria were extracted from leaf bases of 100 healthy Agave tequilana plants. In plant tissue bacteria occurred at mean population densities of 3 million CFU/g of fresh plant tissue. Three hundred endophytic strains were isolated and 16s rDNA sequences grouped the bacteria into eight different taxa that shared high homology with other known sequences. Bacterial endophytes were identified as Acinectobacter sp., A. baumanii, A. bereziniae, Cronobacter sakazakii, Enterobacter hormaechei, Bacillus sp. Klebsiella oxytoca, Pseudomonas sp., Enterococcus casseliflavus, Leuconostoc mesenteroides subsp. mesenteroides and Gluconobacter oxydans. Isolates were confirmed to be plant growth promoting bacteria (PGPB) by their capacities for nitrogen fixation, auxin production, phosphate solubilization, or antagonism against Fusarium oxysporum AC132. E. casseliflavus JM47 and K. oxytoca JM26 secreted the highest concentrations of IAA. The endophyte Acinectobacter sp. JM58 exhibited the maximum values for nitrogen fixation and phosphate solubilization index (PSI). Inhibition of fungi was found in Pseudomonas sp. JM9p and K. oxytoca JM26. Bacterial endophytes show promise for use as bio-inoculants for agave cultivation. Use of endophytes to enhance cultivation of agave may be particularly important for plants produced by micropropagation techniques, where native endophytes may have been lost.

The First Report of Drug Resistant Bacteria Isolated from the Brown-Banded Cockroach, Supella longipalpa, in Ahvaz, South-western Iran

PubMed Central

Vazirianzadeh, Babak; Dehghani, Rouhullah; Mehdinejad, Manijeh; Sharififard, Mona; Nasirabadi, Nersi

2014-01-01

Background The brown-banded cockroach, Supella longipalpa is known as a carrier of pathogenic bacteria in urban environments, but its role is not well documented regarding the carriage of antibiotic-resistant pathogenic bacteria in Iran. The aim of this study was to determine the resistance bacteria isolated from the brown-banded cockroach in Ahvaz, south west of Iran. Methods: Totally 39 cockroaches were collected from kitchen area of houses and identified. All specimens were cultured to isolate the bacterial agents on blood agar and MacConky agar media. The microorganisms were identified using necessary differential and biochemical tests. Antimicrobial susceptibility tests were performed for isolated organisms by Kirby-Bauer’s disk diffusion according to NCLI guideline, using 18 antibiotics. Results: From the 39 collected S. langipalpa, 179 bacterial agents were isolated, 92 of alimentary ducts and 87 of external body surfaces. Isolated bacteria from cockroaches were identified as Enterobacter spp., Klebsiella spp., Citrobacter spp., Escherichia coli, Salmonella spp., Proteus spp., coagulase negative staphylococci, Serratia marcescens, Staphylococcus aureus, and Bacillus species. The pattern resistance rates were determined for gram negative bacilli and gram positive cocci regarding 18 antibiotics. Conclusion: The brown-banded cockroach can be involved in the spread of drug resistant bacteria and increases the possibility of contacting human environment to drug resistant bacteria. Therefore, the potential of removing this insect should be improved. This is the first original report of drug resistant bacteria isolated from the brown-banded cockroach of Iran. PMID:25629065

Dechlorination of 1,1,1-Trichloro-2,2-bis(p-chlorophenyl)ethane by Aerobacter aerogenes

USGS Publications Warehouse

Wedemeyer, Gary

1967-01-01

Whole cells or cell-free extracts of Aerobacter aerogenes catalyze the degradation of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) in vitro to at least seven metabolites: 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE); 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (DDD); 1-chloro-2,2-bis(p-chlorophenyl)ethylene (DDMU); 1-chloro-2,2-bis(p-chlorophenyl)ethane (DDMS); unsym-bis(p-chlorophenyl)ethylene (DDNU); 2,2-bis(p-chlorophenyl)acetate (DDA); and 4,4′-dichlorobenzophenone (DBP). The use of metabolic inhibitors together with pH and temperature studies indicated that discrete enzymes are involved. By use of the technique of sequential analysis, the metabolic pathway was shown to be: DDT → DDD →DDMU →DDMS → DDNU → DDA → DBP, or DDT → DDE. Dechlorination was marginally enhanced by light-activated flavin mononucleotide.

Alimentary Tract Bacteria Isolated and Identified with API-20E and Molecular Cloning Techniques from Australian Tropical Fruit Flies, Bactrocera cacuminata and B. tryoni

PubMed Central

Thaochan, N.; Drew, R. A. I.; Hughes, J. M.; Vijaysegaran, S.; Chinajariyawong, A.

2010-01-01

Bacteria were isolated from the crop and midgut of field collected Bactrocera cacuminata (Hering) and Bactrocera tryoni (Froggatt) (Diptera: Tephritidae). Two methods were used, firstly isolation onto two types of bacteriological culture media (PYEA and TSA) and identification using the API-20E diagnostic kit, and secondly, analysis of samples using the 16S rRNA gene molecular diagnostic method. Using the API-20E method, 10 genera and 17 species of bacteria in the family Enterobacteriaceae were identified from cultures growing on the nutrient agar. The dominant species in both the crop and midgut were Citrobacter freundii, Enterobacter cloacae and Klebsiella oxytoca. Providencia rettgeri, Klebsiella pneumoniae ssp ozaenae and Serratia marcescens were isolated from B. tryoni only. Using the molecular cloning technique that is based on 16S rRNA gene sequences, five bacteria classes were dignosed — Alpha-, Beta-, Gamma- and Delta- Proteobacteria and Firmicutes — including five families, Leuconostocaceae, Enterococcaceae, Acetobacteriaceae, Comamonadaceae and Enterobacteriaceae. The bacteria affiliated with Firmicutes were found mainly in the crop while the Gammaproteobacteria, especially the family Enterobacteriaceae, was dominant in the midgut. This paper presents results from the first known application of molecular cloning techniques to study bacteria within tephritid species and the first record of Firmicutes bacteria in these flies. PMID:20883132

Enhancing the culturability of bacteria from the gastrointestinal tract of farmed adult turbot Scophthalmus maximus

NASA Astrophysics Data System (ADS)

Xing, Mengxin; Hou, Zhanhui; Qu, Yanmei; Liu, Bin

2014-03-01

Eighteen agar media were tested for the culture of gut-associated bacteria from farmed adult turbot ( Scophthalmus maximus), including 16 agar media with or without 1% gastrointestinal (GI) supernatant, or with 2% or 4% GI supernatant. A total of 1 711 colonies were analyzed and 24 operational taxonomic units (OTUs) were identified. The greatest bacterial diversity was isolated on Zobell 2216E/Zobell 2216E+ agar media, whereas MRS/MRS+ agar media produced a low diversity of colonies. Agar media with GI supernatant (1%, 2%, or 4%) showed increased diversity and yielded different profiles of OTUs from the corresponding original media, suggesting that GI supernatant provides substances that enhance the culture efficiency of bacteria from the turbot GI tract. The large majority of the colonies (82%) were γ-Proteobacteria, whereas 15.6% and 2.4% of colonies were Firmicutes and Actinobacteria, respectively. At the genus level, 49.4% of all colonies were assigned to Vibrio. Other potential pathogens, including Pseudomonas, Photobacterium, and Enterobacter, and potential probiotics, including Bacillus, Paenibacillus, and Pseudomonas, were also isolated on agar media. Most cultured bacteria belonged to species that were first described in the turbot GI tract. The impact of these species on turbot physiology and health should be investigated further.

Assessment of microbiological quality of sachet-packaged drinking water in Western Nigeria and its public health significance.

PubMed

Olaoye, O A; Onilude, A A

2009-11-01

To assess the microbiological quality of sachet-packaged drinking water in Western Nigeria and its impact on public health. Cross-sectional microbiological testing. Ninety-two sachet-packaged water samples were analysed for microbiological and metal qualities. Total bacterial and coliform counts were determined, and the presence of Escherichia coli, an important water quality indicator, was tested. The level of conformity of the water processors with the guidelines of Nigeria's quality regulatory agency was also determined. Varying levels of microbial contamination were recorded in samples from the different sampling locations. The total bacteria count ranged between 2.86 and 3.45log colony-forming units (cfu)/ml. The highest coliform count recorded was 1.62log cfu/ml. Faecal coliform E. coli was detected in one sample from Oke-Iho and one sample from Okaka, representing 2.2% of total samples. Lead and manganese were not found in any of the samples. However, iron was detected and the highest iron concentration (0.10mg/l) was detected in samples from Ikorodu. The bacteria that were identified from the water samples included E. coli, Pseudomonas aeruginosa, Enterobacter aerogenes, Klebsiella sp., Proteus vulgaris, Alcaligenes faecalis, Bacillus cereus, Staphylococcus aureus, Streptococcus lactis, Aeromonas sp. and Micrococcus luteum. Many of the water processors did not comply with the guidelines of the quality regulatory agency. Some of the sachet-packaged samples of drinking water were of poor quality. The results indicate a need for Nigeria's quality regulatory agency to take appropriate measures in safeguarding public health.

Occurrence of yeasts, pseudomonads and enteric bacteria in the oral cavity of patients undergoing head and neck radiotherapy

PubMed Central

Gaetti-Jardim, Elerson; Ciesielski, Francisco Isaak Nicolas; de Sousa, Fátima Regina Nunes; Nwaokorie, Francisca; Schweitzer, Christiane Marie; Avila-Campos, Mario Júlio

2011-01-01

The aim of this study was to evaluate the occurrence of yeasts, pseudomonads and enteric bacteria in the oral cavity of patients undergoing radiotherapy (RT) for treatment of head and neck cancer. Fifty patients receiving RT were examined before, during and 30 days after RT. Saliva, mucosa, and biofilm samples were collected and microorganisms were detected by culture and polymerase chain reaction (PCR). The most prevalent yeasts in patients submitted to RT were Candida albicans, C. tropicalis, C. krusei, C. glabrata and C. parapsilosis. Citrobacter, Enterobacter, Enterococcus, Klebsiella, Proteus, and Pseudomonas were the most frequently cultivated bacteria. Before RT, targeted bacteria were cultivated from 22.2% of edentulous patients and 16.6% of dentate patients; 30 days after RT, these microorganisms were recovered from 77.8% edentulous and 46.8% dentate patients. By PCR, these microorganisms were detected from all edentulous patients, 78.1% of dentate patients. The presence of Gram-negative enteric roads and fungi was particularly frequent in patients presenting mucositis level III or IV. Modifications in the oral environment due to RT treatment seem to facilitate the colonization of oral cavity by members of family Enterobacteriaceae, genera Enterococcus and Candida. PMID:24031721

Kinetic characterization of a novel acid ectophosphatase from Enterobacter asburiae.

PubMed

Sato, Vanessa Sayuri; Galdiano Júnior, Renato F; Rodrigues, Gisele Regina; Lemos, Eliana G M; Pizauro Junior, João Martins

2016-02-01

Expression of acid ectophosphatase by Enterobacter asburiae, isolated from Cattleya walkeriana (Orchidaceae) roots and identified by the 16S rRNA gene sequencing analysis, was strictly regulated by phosphorus ions, with its optimal activity being observed at an inorganic phosphate concentration of 7 mM. At the optimum pH 3.5, intact cells released p-nitrophenol at a rate of 350.76 ± 13.53 nmol of p-nitrophenolate (pNP)/min/10(8) cells. The membrane-bound enzyme was obtained by centrifugation at 100,000 × g for 1 h at 4 °C. p-Nitrophenylphosphate (pNPP) hydrolysis by the enzyme follows "Michaelis-Menten" kinetics with V = 61.2 U/mg and K0.5 = 60 μM, while ATP hydrolysis showed V = 19.7 U/mg, K0.5 = 110 μM, and nH = 1.6 and pyrophosphate hydrolysis showed V = 29.7 U/mg, K0.5 = 84 μM, and nH = 2.3. Arsenate and phosphate were competitive inhibitors with K i = 0.6 mM and K i = 1.8 mM, respectively. p-Nitrophenyl phosphatase (pNPPase) activity was inhibited by vanadate, while p-hydroxymercuribenzoate, EDTA, calcium, copper, and cobalt had no inhibitory effects. Magnesium ions were stimulatory (K0.5 = 2.2 mM and nH = 0.5). Production of an acid ectophosphatase can be a mechanism for the solubilization of mineral phosphates by microorganisms such as Enterobacter asburiae that are versatile in the solubilization of insoluble minerals, which, in turn, increases the availability of nutrients for plants, particularly in soils that are poor in phosphorus.

Enterobacter cloacae Complex Isolates Harboring blaNMC-A or blaIMI-Type Class A Carbapenemase Genes on Novel Chromosomal Integrative Elements and Plasmids

PubMed Central

Boyd, David A.; Mataseje, Laura F.; Davidson, Ross; Delport, Johannes A.; Fuller, Jeff; Hoang, Linda; Lefebvre, Brigitte; Levett, Paul N.; Roscoe, Diane L.; Willey, Barbara M.

2017-01-01

ABSTRACT Carbapenem-resistant Enterobacter cloacae complex isolates submitted to a reference laboratory from 2010 to 2015 were screened by PCR for seven common carbapenemase gene groups, namely, KPC, NDM, OXA-48, VIM, IMP, GES, and NMC-A/IMI. Nineteen of the submitted isolates (1.7%) were found to harbor Ambler class A blaNMC-A or blaIMI-type carbapenemases. All 19 isolates were resistant to at least one carbapenem but susceptible to aminoglycosides, trimethoprim-sulfamethoxazole, tigecycline, and ciprofloxacin. Most isolates (17/19) gave positive results with the Carba-NP test for phenotypic carbapenemase detection. Isolates were genetically diverse by pulsed-field gel electrophoresis macrorestriction analysis, multilocus sequence typing, and hsp60 gene analysis. The genes were found in various Enterobacter cloacae complex species; however, blaNMC-A was highly associated with Enterobacter ludwigii. Whole-genome sequencing and bioinformatics analysis revealed that all NMC-A (n = 10), IMI-1 (n = 5), and IMI-9 (n = 2) producers harbored the carbapenemase gene on EludIMEX-1-like integrative mobile elements (EcloIMEXs) located in the identical chromosomal locus. Two novel genes, blaIMI-5 and blaIMI-6, were harbored on different IncFII-type plasmids. Enterobacter cloacae complex isolates harboring blaNMC-A/IMI-type carbapenemases are relatively rare in Canada. Though mostly found integrated into the chromosome, some variants are located on plasmids that may enhance their mobility potential. PMID:28223374

Enterobacter cloacae Complex Isolates Harboring blaNMC-A or blaIMI-Type Class A Carbapenemase Genes on Novel Chromosomal Integrative Elements and Plasmids.

PubMed

Boyd, David A; Mataseje, Laura F; Davidson, Ross; Delport, Johannes A; Fuller, Jeff; Hoang, Linda; Lefebvre, Brigitte; Levett, Paul N; Roscoe, Diane L; Willey, Barbara M; Mulvey, Michael R

2017-05-01

Carbapenem-resistant Enterobacter cloacae complex isolates submitted to a reference laboratory from 2010 to 2015 were screened by PCR for seven common carbapenemase gene groups, namely, KPC, NDM, OXA-48, VIM, IMP, GES, and NMC-A/IMI. Nineteen of the submitted isolates (1.7%) were found to harbor Ambler class A bla NMC-A or bla IMI -type carbapenemases. All 19 isolates were resistant to at least one carbapenem but susceptible to aminoglycosides, trimethoprim-sulfamethoxazole, tigecycline, and ciprofloxacin. Most isolates (17/19) gave positive results with the Carba-NP test for phenotypic carbapenemase detection. Isolates were genetically diverse by pulsed-field gel electrophoresis macrorestriction analysis, multilocus sequence typing, and hsp60 gene analysis. The genes were found in various Enterobacter cloacae complex species; however, bla NMC-A was highly associated with Enterobacter ludwigii Whole-genome sequencing and bioinformatics analysis revealed that all NMC-A ( n = 10), IMI-1 ( n = 5), and IMI-9 ( n = 2) producers harbored the carbapenemase gene on EludIMEX-1-like integrative mobile elements (EcloIMEXs) located in the identical chromosomal locus. Two novel genes, bla IMI-5 and bla IMI-6 , were harbored on different IncFII-type plasmids. Enterobacter cloacae complex isolates harboring bla NMC-A/IMI -type carbapenemases are relatively rare in Canada. Though mostly found integrated into the chromosome, some variants are located on plasmids that may enhance their mobility potential. © Crown copyright 2017.

Effects of the culture media optimization on pectinase production by Enterobacter sp. PSTB-1.

PubMed

Reddy, M Purna Chandra; Saritha, K V

2016-12-01

In the present study, media composition for high production of pectinase by Enterobacter sp. PSTB-1 in submerged fermentation was optimized using response surface methodology (RSM). Mango fruit processing industrial waste (MIW) was used as substrate (carbon source) as it contains high amount of pectin. Enterobacter sp. PSTB-1 used in present study has given pectin clear zone (PCZ) of 34 mm is higher than other isolates. The experimental results made by statistical design for high pectinase production revealed that the suitable media components: NaNO 3 2.0 g/l, KCl 0.50 g/l, KH 2 PO 4 1.0 g/l, MgSO 4 ·7H 2 O 0.50 g/l, Yeast extract 1.0 g/l, mango industrial waste powder 5.0 g/l. The actual pectinase activity was 75.23 % correlated with the predicted pectinase activity where the model (CCD) was significant. Response surface modelling applied effectively to optimize the production of pectinase in submerged fermentation to make the process low cost-effective by using powdered mango industrial waste as substrate.

Enhancement of the catalytic activity of ferulic acid decarboxylase from Enterobacter sp. Px6-4 through random and site-directed mutagenesis.

PubMed

Lee, Hyunji; Park, Jiyoung; Jung, Chaewon; Han, Dongfei; Seo, Jiyoung; Ahn, Joong-Hoon; Chong, Youhoon; Hur, Hor-Gil

2015-11-01

The enzyme ferulic acid decarboxylase (FADase) from Enterobacter sp. Px6-4 catalyzes the decarboxylation reaction of lignin monomers and phenolic compounds such as p-coumaric acid, caffeic acid, and ferulic acid into their corresponding 4-vinyl derivatives, that is, 4-vinylphenol, 4-vinylcatechol, and 4-vinylguaiacol, respectively. Among various ferulic acid decarboxylase enzymes, we chose the FADase from Enterobacter sp. Px6-4, whose crystal structure is known, and produced mutants to enhance its catalytic activity by random and site-directed mutagenesis. After three rounds of sequential mutations, FADase(F95L/D112N/V151I) showed approximately 34-fold higher catalytic activity than wild-type for the production of 4-vinylguaiacol from ferulic acid. Docking analyses suggested that the increased activity of FADase(F95L/D112N/V151I) could be due to formation of compact active site compared with that of the wild-type FADase. Considering the amount of phenolic compounds such as lignin monomers in the biomass components, successfully bioengineered FADase(F95L/D112N/V151I) from Enterobacter sp. Px6-4 could provide an ecofriendly biocatalytic tool for producing diverse styrene derivatives from biomass.

Phosphatase synthesis in Klebsiella (Aerobacter) aerogenes growing in continuous culture

PubMed Central

Bolton, P. G.; Dean, A. C. R.

1972-01-01

1. Phosphatase synthesis was studied in Klebsiella aerogenes grown in a wide range of continuous-culture systems. 2. Maximum acid phosphatase synthesis was associated with nutrient-limited, particularly carbohydrate-limited, growth at a relatively low rate, glucose-limited cells exhibiting the highest activity. Compared with glucose as the carbon-limiting growth material, other sugars not only altered the activity but also changed the pH–activity profile of the enzyme(s). 3. The affinity of the acid phosphatase in glucose-limited cells towards p-nitrophenyl phosphate (Km 0.25–0.43mm) was similar to that of staphylococcal acid phosphatase but was ten times greater than that of the Escherichia coli enzyme. 4. PO43−-limitation derepressed alkaline phosphatase synthesis but the amounts of activity were largely independent of the carbon source used for growth. 5. The enzymes were further differentiated by the effect of adding inhibitors (F−, PO43−) and sugars to the reaction mixture during the assays. In particular, it was shown that adding glucose, but not other sugars, stimulated the rate of hydrolysis of p-nitrophenyl phosphate by the acid phosphatase in carbohydrate-limited cells at low pH values (<4.6) but inhibited it at high pH values (>4.6). Alkaline phosphatase activity was unaffected. 6. The function of phosphatases in general is discussed and possible mechanisms for the glucose effect are outlined. PMID:4342213

The distribution of carbapenem- and colistin-resistance in Gram-negative bacteria from the Tamil Nadu region in India.

PubMed

Manohar, Prasanth; Shanthini, Thamaraiselvan; Ayyanar, Ramankannan; Bozdogan, Bulent; Wilson, Aruni; Tamhankar, Ashok J; Nachimuthu, Ramesh; Lopes, Bruno S

2017-07-01

The occurrence of carbapenem- and colistin-resistance among Gram-negative bacteria is increasing worldwide. The aim of this study was to understand the distribution of carbapenem- and colistin-resistance in two areas in Tamil Nadu, India. The clinical isolates (n=89) used in this study were collected from two diagnostic centres in Tamil Nadu, India. The bacterial isolates were screened for meropenem- and colistin-resistance. Further, resistance genes blaNDM-1, blaOXA-48-like, blaIMP, blaVIM, blaKPC, mcr-1 and mcr-2 and integrons were studied. The synergistic effect of meropenem in combination with colistin was assessed. A total of 89 bacterial isolates were studied which included Escherichia coli (n=43), Klebsiella pneumoniae (n=18), Pseudomonas aeruginosa (n=10), Enterobacter cloacae (n=6), Acinetobacter baumannii (n=5), Klebsiella oxytoca (n=4), Proteus mirabilis (n=2) and Salmonella paratyphi (n=1). MIC testing showed that 58/89 (65 %) and 29/89 (32 %) isolates were resistant to meropenem and colistin, respectively, whereas 27/89 (30 %) isolates were resistant to both antibiotics. Escherichia coli, K. pneumoniae, K. oxytoca, Pseudomonas aeruginosa, and Enterobacter cloacae isolates were blaNDM-1-positive (n=20). Some strains of Escherichia coli, K. pneumoniae and K. oxytoca were blaOXA-181-positive (n=4). Class 1, 2 and 3 integrons were found in 24, 20 and 3 isolates, respectively. Nine NDM-1-positive Escherichia coli strains could transfer carbapenem resistance via plasmids to susceptible Escherichia coli AB1157. Meropenem and colistin showed synergy in 10/20 (50 %) isolates by 24 h time-kill studies. Our results highlight the distribution of carbapenem- and colistin-resistance in Gram-negative bacteria isolated from the Tamil Nadu region in South India.

Widespread Fosfomycin Resistance in Gram-Negative Bacteria Attributable to the Chromosomal fosA Gene

PubMed Central

Ito, Ryota; Tomich, Adam D.; Callaghan, Jake D.; McElheny, Christi L.; Mettus, Roberta T.; Sluis-Cremer, Nicolas

2017-01-01

ABSTRACT Fosfomycin is a decades-old antibiotic which is being revisited because of its perceived activity against many extensively drug-resistant Gram-negative pathogens. FosA proteins are Mn2+ and K+-dependent glutathione S-transferases which confer fosfomycin resistance in Gram-negative bacteria by conjugation of glutathione to the antibiotic. Plasmid-borne fosA variants have been reported in fosfomycin-resistant Escherichia coli strains. However, the prevalence and distribution of fosA in other Gram-negative bacteria are not known. We systematically surveyed the presence of fosA in Gram-negative bacteria in over 18,000 published genomes from 18 Gram-negative species and investigated their contribution to fosfomycin resistance. We show that FosA homologues are present in the majority of genomes in some species (e.g., Klebsiella spp., Enterobacter spp., Serratia marcescens, and Pseudomonas aeruginosa), whereas they are largely absent in others (e.g., E. coli, Acinetobacter baumannii, and Burkholderia cepacia). FosA proteins in different bacterial pathogens are highly divergent, but key amino acid residues in the active site are conserved. Chromosomal fosA genes conferred high-level fosfomycin resistance when expressed in E. coli, and deletion of chromosomal fosA in S. marcescens eliminated fosfomycin resistance. Our results indicate that FosA is encoded by clinically relevant Gram-negative species and contributes to intrinsic fosfomycin resistance. PMID:28851843

Effect of cadmium on lake water bacteria as determined by the luciferase assay of adenosine triphosphate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seyfried, P.L.; Horgan, C.B.L.

1981-10-01

A firefly luciferase assay of bacterial adenosine triphosphate (ATP) was developed to measure the toxic effects of cadmium ions on aquatic organisms. Toxicity was monitored using intracellular (I/C) ATP (in micrograms per litre) as well as plate counts (colony-forming units per millilitre). The bacteria, which belonged mainly to the families Enterobacteriaceae and Pseudomonadaceae, exhibited varying degrees of resistance to up to 100 ppm cadmium when grown in a glucose-salts medium at pH 6.8. Among the organisms tested, cadmium resistance decreased in the following order: Pseudomonas vesicularis > P. aeruginosa > Enterobacter sp. > P. fluorescens > Chromobacter sp. > Serratiamore » sp. A rise in the pH of the growth medium from 5 to 7 resulted in increased toxicity of cadmium.« less

Bacterial contaminants from frozen puff pastry production process and their growth inhibition by antimicrobial substances from lactic acid bacteria.

PubMed

Rumjuankiat, Kittaporn; Keawsompong, Suttipun; Nitisinprasert, Sunee

2017-05-01

Seventy-five bacterial contaminants which still persisted to cleaning system from three puff pastry production lines (dough forming, layer and filling forming, and shock freezing) were identified using 16S rDNA as seven genera of Bacillus , Corynebacterium , Dermacoccus , Enterobacter , Klebsiella, Pseudomonas , and Staphylococcus with detection frequencies of 24.00, 2.66, 1.33, 37.33, 1.33, 2.66, and 30.66, respectively. Seventeen species were discovered while only 11 species Bacillus cereus, B. subtilis, B. pumilus, Corynebacterium striatum , Dermacoccus barathri , Enterobacter asburiae, Staphylococcus kloosii, S. haemolyticus, S. hominis, S. warneri , and S. aureus were detected at the end of production. Based on their abundance, the highest abundance of E. asburiae could be used as a biomarker for product quality. While a low abundance of the mesophile pathogen C. striatum , which causes respiratory and nervous infection and appeared only at the shock freezing step was firstly reported for its detection in bakery product. Six antimicrobial substances (AMSs) from lactic acid bacteria, FF1-4, FF1-7, PFUR-242, PFUR-255, PP-174, and nisin A were tested for their inhibition activities against the contaminants. The three most effective were FF1-7, PP-174, and nisin A exhibiting wide inhibition spectra of 88.00%, 85.33%, and 86.66%, respectively. The potential of a disinfectant solution containing 800 AU/ml of PP-174 and nisin A against the most resistant strains of Enterobacter , Staphylococcus , Bacillus and Klebsiella was determined on artificially contaminated conveyor belt coupons at 0, 4, 8, 12, and 16 hr. The survival levels of the test strains were below 1 log CFU/coupon at 0 hr. The results suggested that a combined solution of PP-174 and nisin A may be beneficial as a sanitizer to inhibit bacterial contaminants in the frozen puff pastry industry.

Genotypic and Phenotypic Detection of AmpC β-lactamases in Enterobacter spp. Isolated from a Teaching Hospital in Malaysia.

PubMed

Mohd Khari, Fatin Izzati; Karunakaran, Rina; Rosli, Roshalina; Tee Tay, Sun

2016-01-01

The objective of this study was to determine the occurrence of chromosomal and plasmid-mediated β-lactamases (AmpC) genes in a collection of Malaysian isolates of Enterobacter species. Several phenotypic tests for detection of AmpC production of Enterobacter spp. were evaluated and the agreements between tests were determined. Antimicrobial susceptibility profiles for 117 Enterobacter clinical isolates obtained from the Medical Microbiology Diagnostic Laboratory, University Malaya Medical Centre, Malaysia, from November 2012-February 2014 were determined in accordance to CLSI guidelines. AmpC genes were detected using a multiplex PCR assay targeting the MIR/ACT gene (closely related to chromosomal EBC family gene) and other plasmid-mediated genes, including DHA, MOX, CMY, ACC, and FOX. The AmpC β-lactamase production of the isolates was assessed using cefoxitin disk screening test, D69C AmpC detection set, cefoxitin-cloxacillin double disk synergy test (CC-DDS) and AmpC induction test. Among the Enterobacter isolates in this study, 39.3% were resistant to cefotaxime and ceftriaxone and 23.9% were resistant to ceftazidime. Ten (8.5%) of the isolates were resistant to cefepime, and one isolate was resistant to meropenem. Chromosomal EBC family gene was amplified from 36 (47.4%) E. cloacae and three (25%) E. asburiae. A novel blaDHA type plasmid-mediated AmpC gene was identified for the first time from an E. cloacae isolate. AmpC β-lactamase production was detected in 99 (89.2%) of 111 potential AmpC β-lactamase producers (positive in cefoxitin disk screening) using D69C AmpC detection set. The detection rates were lower with CC-DDS (80.2%) and AmpC induction tests (50.5%). There was low agreement between the D69C AmpC detection set and the other two phenotypic tests. Of the 40 isolates with AmpC genes detected in this study, 87.5%, 77.5% and 50.0% of these isolates were positive by the D69C AmpC detection set, CC-DDS and AmpC induction tests, respectively

Genotypic and Phenotypic Detection of AmpC β-lactamases in Enterobacter spp. Isolated from a Teaching Hospital in Malaysia

PubMed Central

Mohd Khari, Fatin Izzati; Karunakaran, Rina; Rosli, Roshalina; Tee Tay, Sun

2016-01-01

Objectives The objective of this study was to determine the occurrence of chromosomal and plasmid-mediated β-lactamases (AmpC) genes in a collection of Malaysian isolates of Enterobacter species. Several phenotypic tests for detection of AmpC production of Enterobacter spp. were evaluated and the agreements between tests were determined. Methods Antimicrobial susceptibility profiles for 117 Enterobacter clinical isolates obtained from the Medical Microbiology Diagnostic Laboratory, University Malaya Medical Centre, Malaysia, from November 2012—February 2014 were determined in accordance to CLSI guidelines. AmpC genes were detected using a multiplex PCR assay targeting the MIR/ACT gene (closely related to chromosomal EBC family gene) and other plasmid-mediated genes, including DHA, MOX, CMY, ACC, and FOX. The AmpC β-lactamase production of the isolates was assessed using cefoxitin disk screening test, D69C AmpC detection set, cefoxitin-cloxacillin double disk synergy test (CC-DDS) and AmpC induction test. Results Among the Enterobacter isolates in this study, 39.3% were resistant to cefotaxime and ceftriaxone and 23.9% were resistant to ceftazidime. Ten (8.5%) of the isolates were resistant to cefepime, and one isolate was resistant to meropenem. Chromosomal EBC family gene was amplified from 36 (47.4%) E. cloacae and three (25%) E. asburiae. A novel blaDHA type plasmid-mediated AmpC gene was identified for the first time from an E. cloacae isolate. AmpC β-lactamase production was detected in 99 (89.2%) of 111 potential AmpC β-lactamase producers (positive in cefoxitin disk screening) using D69C AmpC detection set. The detection rates were lower with CC-DDS (80.2%) and AmpC induction tests (50.5%). There was low agreement between the D69C AmpC detection set and the other two phenotypic tests. Of the 40 isolates with AmpC genes detected in this study, 87.5%, 77.5% and 50.0% of these isolates were positive by the D69C AmpC detection set, CC-DDS and Amp

Antibiogram of bacteria isolated from automated teller machines in Hamadan, West Iran

PubMed Central

Mahmoudi, Hassan; Arabestani, Mohammad Reza; Alikhani, Mohammad Yousef; Sedighi, Iraj; Kohan, Hamed Farhadi; Molavi, Mohammad

2017-01-01

Aim: Bacteria are ubiquitous in the environment. In keeping with the continued expansion of urbanization and the growing population, an increasing number of people use automated banking, i.e. automated teller machines (ATMs). The aim of this study was to investigate the bacterial contamination and its antibiotic sensitivity on computer keyboards located at ATMs in Hamadan province, Iran. Method: Out of 360 ATMs at four locations in Hamadan, 96 were randomly selected for this study. The antibiotic susceptibility pattern of all isolates was determined by the agar disk diffusion method using gentamicin (10 µg), vancomycin (30 µg), trimethoprim/sulfamethoxazole (25 µg), amikacin (30 µg), tobramycin (10 µg), cephalotin (30 µg), norfloxacin (5 µg), and ceftizoxim (30 µg) disks. Results: Melli and Saderat Banks had the most frequently contaminated ATMS, with 18 (27.7%) and 12 (18.5%), respectively. The most frequently isolated bacteria were Staphylococcus epidermidis in 12 (18.5%) ATMs, Pseudomonas aeruginosa in 12 (18.5%), Bacillus subtilis in 11 (16.9%), Escherichia coli in 6 (9.2%), Klebsiella spp. in 8 (12.3%), Enterobacter spp. in 2 (3.1%), Bacillus cereus in 6 (9.2%), Staphylococcus aureus in 3 (4.6%), and Micrococcaceae spp. in 5 (7.69%) cases. All isolated bacteria were susceptible to gentamicin, cephalotin, tobramycin, amikacin, norfloxacin, and vancomycin. The S. aureus resistance rate to trimethoprim/sulfamethoxazole was 50%. Conclusion: All tested ATM keyboards were contaminated with at least one species of bacteria. Based on these findings, it is recommendable to disinfect the hands after entering one’s own apartment, work area or a hospital, in order to hinder the spread of critical pathogens in the personal environment or in the hospital. PMID:28197394

Incidence of multidrug-resistant, extensively drug-resistant and pan-drug-resistant bacteria in children hospitalized at Dr. Hasan Sadikin general hospital Bandung Indonesia

NASA Astrophysics Data System (ADS)

Adrizain, R.; Suryaningrat, F.; Alam, A.; Setiabudi, D.

2018-03-01

Antibiotic resistance has become a global issue, with 700,000 deaths attributable to multidrug-resistance (MDR) occurring each year. Centers for Disease Control and Prevention (CDC) show rapidly increasing rates of infection due to antibiotic-resistant bacteria. The aim of the study isto describe the incidence of MDR, extensively drug-resistant (XDR) and pan drug-resistant (PDR) in Enterococcus spp., Staphylococcus aureus, K. pneumonia, Acinetobacter baumanii, P. aeruginosin, and Enterobacter spp. (ESKAPE) pathogens in children admitted to Dr. Hasan Sadikin Hospital. All pediatric patients having blood culture drawn from January 2015 to December 2016 were retrospectively studied. Data include the number of drawn blood culture, number of positive results, type of bacteria, sensitivity pattern. International standard definitions for acquired resistance by ECDC and CDC was used as definitions for MDR, XDR and PDR bacteria. From January 2015 to December 2016, 299 from 2.542 (11.7%) blood culture was positive, with Staphylococcus aureus, Enterococcus spp., Enterobacteriaceae, Pseudomonas aeruginosa, Acinetobacter spp., respectively 5, 6, 24, 5, 20 with total 60 (20%). The MDR and XDR pathogen found were 47 and 13 patients, respectively.

Synthesis and structure-activity relationship of novel bisindole amidines active against MDR Gram-positive and Gram-negative bacteria.

PubMed

Liu, Yonghua; Hu, Xinxin; Wu, Yanbin; Zhang, Weixing; Chen, Xiaofang; You, Xuefu; Hu, Laixing

2018-04-25

A series of novel diamidines with N-substituents on an amidine N-atom were synthesized and evaluated for their cytotoxicity and in vitro antibacterial activity against a range of Gram-positive and Gram-negative bacterial strains. Based on structure-activity relationship, N-substituents with a branched chain and a shorter carbon chain on the amidine N-atom exhibited more promising activity against Gram-negative and MDR-Gram-positive bacteria; compounds 5c and 5i were the most powerful candidate compounds. Compound 5c showed greater efficacy than levofloxacin against most drug-resistant Gram-positive bacteria and exhibited broad-spectrum antibacterial activity against Gram-negative bacteria, with MIC values in the range of 2-16 μg/mL. Slightly more potent antibacterial activity against Klebsiella pneumoniae, Acinetobacter calcoaceticus, Enterobacter cloacae, and Proteus mirabilis was observed for 5i in comparison with 5c. Compound 5i also showed remarkable antibacterial activity against NDM-1-producing Gram-negative bacteria, with MIC values in the range of 2-4 μg/mL, and was superior to the reference drugs meropenem and levofloxacin. Effective antibacterial activity of 5i was also shown in vivo in a mouse model of Staphylococcus aureus MRSA strain, with an ED 50 values of 2.62 mg/kg. Copyright © 2018. Published by Elsevier Masson SAS.

Optimization of biodegradable plastic production on sugar cane molasses in Enterobacter sp. SEL2

PubMed Central

Naheed, Nighat; Jamil, Nazia

2014-01-01

Contaminated environments have a large number of bacteria which can accumulate PHA as their energy reserves. Out of 54 isolated bacterial strains from three groups of contaminated sites 48 were found PHA positive. The sites were grouped on the basis of the type of carbon sources i.e. sugars, fatty acids and much diverse type. Strains MFD5, MFD11, UML3, USL2, SEL2, SEL3, SEL10 and PFW1 produced 69.9 ± 0.29, 75.27 ± 0.45, 65.43 ± 0.1, 72.54 ± 0.27, 76.61 ± 0.28, 61.81 ± 0.05, 71.16 ± 0.09 and 74.92 ± 0.5 percent of PHA to their constant cell weight (CCW) respectively in PHA detection media supplemented with 2% glucose. Molasses, whey, crumbs hydrolysate and palm oil were checked as inexpensive carbon sources. Molasses alone could supply the required nutrients for growth and PHA production. Strain SEL2 produced 47.36 ± 0.45% PHA using 2% molasses at 37 °C and pH 7.0. Upon production optimization the best accumulation (80.95 ± 0.01%) was observed in PHA detection media with 0.2% nitrogen source, 3% molasses, pH 5.0 and 37 °C by the strain SEL2. The overall effect of the presence of increased molasses concentration in the media was positive it increased the accumulation period till 72 h. Enterobacter sp. SEL2 (JF901810) is first time being reported for PHA production. PMID:25242924

Biodegradation of ichlorodiphenyltrichloroe-thane: Intermediates in dichlorodiphenylacetic acid metabolism by Aerobacter aerogenes

USGS Publications Warehouse

1967-01-01

The final product of dichlorodiphenyltrichloroethane (DDT) degradation by vertebrates is commonly considered to be dichlorodiphenylacetic acid, DDA (J. E. Peterson and W. H. Robison, Toxicol. Appl. Pharmacol. 6:321, 1964). Recently, certain organisms (A. S. Perry, S. Miller, and A. J. Buckner. J. Agr. Food Chem. 11:457, 1963; J. D. Pinto, M. N. Comien, and M. S. Dunn. J. Biol. Chem. 240:2148, 1965) have been found to degrade further DDA to dichlorobenzophenone (DBP), but the possibility that such degradation was due to microbial action could not be excluded. Significantly, dichlorobenzhydrol (DBH), dichlorophenylmethane (DPM), and dichlorodiphenylethylene (DDE) have been tentatively identified in rats fed DDA (Pinto et al., J. Biol. Chem. 240:2148, 1965). Since DDA as well as DDT is degraded by the ubiquitous microorganism Aerobacter aerogenes (G. Wedemeyer, Appl. Microbiol. 15:569, 1967; J. L. Mendel, and M. S. Walton, Science 151:1527, 1966), it seemed reasonable that the intestinal microflora might be involved in DBP formation, DPM and DBH being intermediates in its pathway from DDA. Since DDA is a (3,y-unsaturated acid, ketone formation via an alkene and an alcohol would be expected (S. G. Waley, Mechanisms of Organic and Enzymatic Reactions, Oxford University Press, London, England 1962).

Identification of regulated genes conferring resistance to high concentrations of glyphosate in a new strain of Enterobacter.

PubMed

Fei, Yun-Yan; Gai, Jun-Yi; Zhao, Tuan-Jie

2013-12-01

Glyphosate is a widely used herbicide that inhibits 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) activity. Most plants and microbes are sensitive to glyphosate. However, transgenic-resistant crops that contain a modified epsps obtained from the resistant microbes have been commercially successful and therefore, new resistance genes and their adaptive regulatory mechanisms are of great interest. In this study, a soil-borne, glyphosate-resistant bacterium was selected and identified as Enterobacter. The EPSPS in this strain was found to have been altered to a resistant one. A total of 42 differentially expressed genes (DEGs) in the glyphosate were screened using microarray techniques. Under treatment, argF, sdhA, ivbL, rrfA-H were downregulated, whereas the transcripts of speA, osmY, pflB, ahpC, fusA, deoA, uxaC, rpoD and a few ribosomal protein genes were upregulated. Data were verified by quantitative real-time PCR on selected genes. All transcriptional changes appeared to protect the bacteria from glyphosate and associated osmotic, acidic and oxidative stresses. Many DEGs may have the potential to confer resistance to glyphosate alone, and some may be closely related to the shikimate pathway, reflecting the complex gene interaction network for glyphosate resistance. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Antimicrobial peptide gene induction, involvement of Toll and IMD pathways and defense against bacteria in the red flour beetle, Tribolium castaneum.

PubMed

Yokoi, Kakeru; Koyama, Hiroaki; Minakuchi, Chieka; Tanaka, Toshiharu; Miura, Ken

2012-01-01

Using Tribolium castaneum, we quantitatively investigated the induction of nine antimicrobial peptide (AMP) genes by live gram-negative bacteria (Escherichia coli and Enterobacter cloacae), gram-positive bacteria (Micrococcus luteus and Bacillus subtilis) and the budding yeast (Saccharomyces cerevisiae). Then, five representative AMP genes were selected, and the involvement of the Toll and IMD pathways in their induction by E. coli, M. luteus and S. cerevisiae was examined by utilizing RNA interference of either MyD88 or IMD. Results indicated: Robust and acute induction of three genes by the two bacterial species was mediated mainly by the IMD pathway; slow and sustained induction of one gene by the two bacteria was mediated mainly by the Toll pathway; induction of the remaining one gene by the two bacteria was mediated by both pathways; induction of the five genes by the yeast was mediated by the Toll and/or IMD pathways depending on respective genes. These results suggest that more promiscuous activation and usage of the two pathways may occur in T. castaneum than in Drosophila melanogaster. In addition, the IMD pathway was revealed to dominantly contribute to defense against two bacterial species, gram-negative E. cloacae and gram-positive B. subtilis that possesses DAP-type peptidoglycan.

ENTEROPATHOGENS DETECTED IN A DAYCARE CENTER, SOUTHEASTERN BRAZIL: BACTERIA, VIRUS, AND PARASITE RESEARCH

PubMed Central

Castro, Edna Donizetti Rossi; Germini, Marcela Cristina Braga Yassaka; Mascarenhas, Joana D'Arc Pereira; Gabbay, Yvone Benchimol; de Lima, Ian Carlos Gomes; Lobo, Patrícia dos Santos; Fraga, Valéria Daltibari; Conceição, Luciana Moran; Machado, Ricardo Luiz Dantas; Rossit, Andréa Regina Baptista

2015-01-01

Introduction: The objective of this study was to determine the prevalence and etiological profile of enteropathogens in children from a daycare center. Methods: From October 2010 to February 2011 stool samples from 100 children enrolled in a government daycare center in the municipality of São José do Rio Preto, in the state of São Paulo, were collected and analyzed. Results: A total of 246 bacteria were isolated in 99% of the fecal samples; 129 were in the diarrheal group and 117 in the non-diarrheal group. Seventy-three strains of Escherichia coli were isolated, 19 of Enterobacter, one of Alcaligenes and one of Proteus. There were 14 cases of mixed colonization with Enterobacter and E. coli. Norovirus and Astrovirus were detected in children with clinical signs suggestive of diarrhea. These viruses were detected exclusively among children residing in urban areas. All fecal samples were negative for the presence of the rotavirus species A and C. The presence of Giardia lamblia, Entamoeba coli, Endolimax nana and hookworm was observed. A significant association was found between food consumption outside home and daycare center and the presence of intestinal parasites. Conclusions: For children of this daycare center, intestinal infection due to pathogens does not seem to have contributed to the occurrence of diarrhea or other intestinal symptoms. The observed differences may be due to the wide diversity of geographical, social and economic characteristics and the climate of Brazil, all of which have been reported as critical factors in the modulation of the frequency of different enteropathogens. PMID:25651323