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.

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

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...

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 ...

Infective endocarditis due to Enterobacter cloacae resistant to third- and fourth-generation cephalosporins.

PubMed

Yoshino, Yusuke; Okugawa, Shu; Kimura, Satoshi; Makita, Eiko; Seo, Kazunori; Koga, Ichiro; Matsunaga, Naohisa; Kitazawa, Takatoshi; Ota, Yasuo

2015-04-01

We report the case of using a long-term combination of meropenem and amikacin to treat infective endocarditis caused by Enterobacter cloacae resistant to third- and fourth-generation cephalosporins. Multi-drug resistant Gram-negative bacilli, such as the E. cloacae in our study, may become possible pathogens of infective endocarditis. Our experience with this case indicates that long-term use of a combination of β-lactam and aminoglycosides might represent a suitable management option for future infective endocarditis cases due to non-Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella spp. (HACEK group) Gram-negative bacilli such as ours. Copyright © 2012. Published by Elsevier B.V.

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.

Enterobacter cloacae administration induces hepatic damage and subcutaneous fat accumulation in high-fat diet fed mice.

PubMed

Keskitalo, Anniina; Munukka, Eveliina; Toivonen, Raine; Hollmén, Maija; Kainulainen, Heikki; Huovinen, Pentti; Jalkanen, Sirpa; Pekkala, Satu

2018-01-01

Accumulating evidence indicates that gut microbiota plays a significant role in obesity, insulin resistance and associated liver disorders. Family Enterobacteriaceae and especially Enterobacter cloacae strain B29 have been previously linked to obesity and hepatic damage. The underlying mechanisms, however, remain unclear. Therefore, we comprehensively examined the effects of E. cloacae subsp. cloacae (ATCC® 13047™) administration on host metabolism of mice fed with high-fat diet (HFD). C57BL/6N mice were randomly divided into HFD control, chow control, and E. cloacae treatment groups. The E. cloacae treatment group received live bacterial cells in PBS intragastrically twice a week, every other week for 13 weeks. Both control groups received PBS intragastrically. After the 13-week treatment period, the mice were sacrificed for gene and protein expression and functional analyses. Our results show that E. cloacae administration increased subcutaneous fat mass and the relative proportion of hypertrophic adipocytes. Both subcutaneous and visceral fat had signs of decreased insulin signaling and elevated lipolysis that was reflected in higher serum glycerol levels. In addition, E. cloacae -treated mice had significantly higher hepatic AST and AST/ALT ratio, and their liver histology indicated fibrosis, demonstrating that E. cloacae subsp. cloacae administration promotes hepatic damage in HFD fed mice.

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.

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

Draft genome sequence of Enterobacter cloacae HBY, a ST128 clinical strain co-producing KPC-2 and NDM-1 carbapenemases.

PubMed

Li, Xi; Zhu, Yongze; Shen, Mengyuan; Du, Jing; Zhang, Lei; Wang, Dairong

2018-03-01

Enterobacter cloacae is one of the major pathogens responsible for a variety of human infections. Here we report the draft genome sequence of multidrug-resistant E. cloacae strain HBY isolated from a female patient in China. Whole genomic DNA of E. cloacae strain HBY was extracted and was sequenced using an Illumina HiSeq™ 2000 platform. The generated sequence reads were assembled using CLC Genomics Workbench. The draft genome was annotated using Rapid Annotations using Subsystems Technology (RAST), and the presence of antimicrobial resistance genes was identified. The 5799439-bp genome contains various antimicrobial resistance genes conferring resistance to aminoglycosides, β-lactams, fosfomycin, macrolides, sulphonamides and fluoroquinolones. Notably, the strain was identified to carry two main carbapenemase genes (bla KPC-2 and bla NDM-1 ). The genome sequence reported in this study will provide valuable information to understand antibiotic resistance mechanisms in this strain. It is important to monitor the spread strains of Enterobacter sp. encoding both of these carbapenemase genes. Copyright © 2017 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved.

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.

Particular Distribution of Enterobacter cloacae Strains Isolated from Urinary Tract Infection within Clonal Complexes.

PubMed

Akbari, Majid; Bakhshi, Bita; Najar Peerayeh, Shahin

2016-01-01

Based on biochemical properties, Enterobacter cloacae represents a large complex of at least 13 variant species, subspecies, and genotypes that progressively identified as the most species causing hospital-acquired infections. The aim of this study was to determine the relevance between phylogenetically related strains within the E. cloacae complex and the frequency of urinary tract infection caused by them. A 268-bp fragment was obtained from hsp60 gene for 50 clinical E. cloacae isolates from urine cultures of inpatients that admitted to six hospitals in Tehran, Iran during December 2012 to November 2013. The 107 nucleotide sequences were analyzed and the evolutionary distances of sequences were computed and neighbor-joining tree was calculated. It showed that all of the genetic clusters have not an equal involvement in pathogenesis of urinary tract infections. Three superior clusters were found, together representing more than two third (80%) of the isolates (cluster VI with 25 members; clusters III and VIII with 9 and 6 members, respectively) and some genetic clusters were absent (IV, X, XII, and xiii), some of which are supposed to be associated with plants and no human infection has been reported. This study, for the first time, reports the unequal contribution of E. cloacae complex subspecies and clusters in urinary tract infections in Iran and together with studies from other countries suggest that the subspecies of E.hormaechei subsp. Oharae is the most prevalent E. cloacae complex subspecies regardless of country under study.

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.

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.

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

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.

Fluoroquinolone Resistance Mechanisms and population structure of Enterobacter cloacae non-susceptible to Ertapenem in North-Eastern France

PubMed Central

Guillard, Thomas; Cholley, Pascal; Limelette, Anne; Hocquet, Didier; Matton, Lucie; Guyeux, Christophe; Lebreil, Anne-Laure; Bajolet, Odile; Brasme, Lucien; Madoux, Janick; Vernet-Garnier, Véronique; Barbe, Coralie; Bertrand, Xavier; de Champs on behalf of CarbaFrEst Group, Christophe

2015-01-01

Fluoroquinolone (FQ) agents are a potential resort to treat infection due to Enterobacteriaceae producing extended spectrum β-lactamase and susceptible to FQ. In a context of increase of non-susceptibility to carbapenems among Enterobacteriaceae, we characterized FQ resistance mechanisms in 75 Enterobacter cloacae isolates non-susceptible to ertapenem in North-Eastern France in 2012 and describe the population structure by pulsed field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). Among them, 14.7% (12/75) carried a carbapenemase-encoding gene. Except one isolate producing VIM-1, the carbapenemase-producing isolates carried the well-known IncL/M pOXA48a plasmid. Most of the isolates (59/75) harbored at least a FQ-R determinant. qnr genes were predominant (40%, 30/75). The MLST study revealed that E. cloacae isolates’ clonality was wide [24 different sequence types (STs)]. The more widespread STs were ST74, ST101, ST110, ST114, and ST133. Carbapenem MICs were higher for E. cloacae ST74 than for other E. cloacae isolates. Plasmid-mediated quinolone resistance determinants were more often observed in E. cloacae ST74 isolates. These findings showed that (i) pOXA-48a is spreading in North-Eastern France, (ii) qnr is preponderant in E. cloacae, (iii) E. cloacae comprised a large amount of lineages spreading in North-Eastern France, and (iv) FQ as an alternative to β-lactams to treat ertapenem non-susceptible Enterobacteriaceae are compromised. PMID:26557115

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

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.

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...

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.

Galleria mellonella as an in vivo model for assessing the efficacy of antimicrobial agents against Enterobacter cloacae infection.

PubMed

Yang, Hai-Fei; Pan, Ai-Jun; Hu, Li-Fen; Liu, Yan-Yan; Cheng, Jun; Ye, Ying; Li, Jia-Bin

2017-02-01

Enterobacter cloacae is a well-recognized nosocomial pathogen. Use of a rapid, in vivo infection model for E. cloacae that can determine the efficacy of antibiotic therapies could help facilitate screening for new treatments. Nonmammalian model systems of infection, such as Galleria mellonella, have significant logistical and ethical advantages over mammalian models. We utilized G. mellonella larvae to determine the utility of this infection model to study antibacterial efficacy. G. mellonella killing with heat-killed or live clinical isolates (E. cloacae GN1059 and GN0791) was tested. We also investigated the effect of postinoculation incubation temperature on the survival of infected larvae. The protection of administration of antibiotics to infected larvae was investigated. Finally, we determined the G. mellonella hemolymph burden of E. cloacae after administration of different antibiotics. With live bacterial inocula, G. mellonella killing was significantly dependent on the number of E. cloacae cells injected in a dose-dependent manner. Further, we observed that survival was reduced with increasing the postinoculation temperature. Treatment of a lethal E. cloacae infection with antibiotics that had in vitro activity significantly prolonged the survival of larvae compared with treatment with antibiotics to which the bacteria were resistant. The therapeutic benefit arising from administration of antibiotic correlated with a reduced burden of E. cloacae cells in the hemolymph. The G. mellonella infection model has the potential to be used to facilitate the in vivo study of host-pathogen interactions in E. cloacae and the efficacy of antibacterial agents. Copyright © 2014. Published by Elsevier B.V.

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

Optimization of Enterobacter cloacae (KU923381) for diesel oil degradation using response surface methodology (RSM).

PubMed

Ramasamy, Sugumar; Arumugam, Arumugam; Chandran, Preethy

2017-02-01

Efficiency of Enterobacter cloacae KU923381 isolated from petroleum hydrocarbon contaminated soil was evaluated in batch culture and bioreactor mode. The isolate were screened for biofilm formation using qualitative and quantitative assays. Response surface methodology (RSM) was used to study the effect of pH, temperature, glucose concentration, and sodium chloride on diesel degradation. The predicted values for diesel oil degradation efficiency by the statistical designs are in a close agreement with experimental data (R 2 = 99.66%). Degradation efficiency is increased by 36.78% at pH = 7, temperature = 35°C, glucose = 5%, and sodium chloride concentration = 5%. Under the optimized conditions, the experiments were performed for diesel oil degradation by gas chromatographic mass spectrometric analysis (GC-MS). GC-MS analysis confirmed that E. cloacae had highly degrade hexadecane, heptadecane, tridecane, and docosane by 99.71%, 99.23%, 99.66%, and 98.34% respectively. This study shows that rapid bioremoval of hydrocarbons in diesel oil is acheived by E. cloacae with abet of biofilm formation. The potential use of the biofilms for preparing trickling filters (gravel particles) for the degradation of hydrocarbons from petroleum wastes before their disposal in the open environment is highly suggested. This is the first successful attempt for artificially establishing petroleum hydrocarbon degrading bacterial biofilm on solid substrates in bioreactor.

Effects of Enterobacter cloacae on boar sperm quality during liquid storage at 17°C.

PubMed

Prieto-Martínez, Noelia; Bussalleu, Eva; Garcia-Bonavila, Estela; Bonet, Sergi; Yeste, Marc

2014-07-01

Contamination of fresh and extended boar sperm often occurs in farms and artificial insemination (AI) centres during semen collection, processing and storage. The presence of bacteria produces detrimental effects on boar sperm quality, which may cause economic losses in reproductive centres. The present study has evaluated for the first time how the presence of Enterobacter cloacae affects the preservation of boar spermatozoa in liquid storage at 15-17 °C for an 11-day period. With this purpose, extended semen samples from seven healthy post-pubertal boars were artificially contaminated with different sperm:bacterium ratios (2:1; 1:1; 1:5 and 1:10) of E. cloacae. The 1:0 ratio (non-inoculated) served as a negative control. The most infective ratios (i.e. 1:5 and 1:10) significantly damaged sperm motility and membrane integrity, increased sperm agglutination, and decreased the osmotic resistance of spermatozoa. In contrast, the negative impact that the lowest bacterial concentration (2:1) had on boar sperm quality was clearly lower. In addition, other parameters such as pH were also more affected at the highest infective ratios (i.e. 1:5 and 1:10), despite no damage being observed on sperm morphology. In conclusion, the present work shows that damage inflicted by the presence of E. cloacae in boar sperm during liquid storage at 15-17 °C compromises the longevity and fertilising ability of seminal doses when bacterial concentration is higher than a 1:1 ratio. Further research is warranted to address by which mechanism E. cloacae impairs boar sperm quality. Copyright © 2014 Elsevier B.V. All rights reserved.

Aerobic Degradation of 2,4,6-Trinitrotoluene by Enterobacter cloacae PB2 and by Pentaerythritol Tetranitrate Reductase

PubMed Central

French, Christopher E.; Nicklin, Stephen; Bruce, Neil C.

1998-01-01

Enterobacter cloacae PB2 was originally isolated on the basis of its ability to utilize nitrate esters, such as pentaerythritol tetranitrate (PETN) and glycerol trinitrate, as the sole nitrogen source for growth. The enzyme responsible is an NADPH-dependent reductase designated PETN reductase. E. cloacae PB2 was found to be capable of slow aerobic growth with 2,4,6-trinitrotoluene (TNT) as the sole nitrogen source. Dinitrotoluenes were not produced and could not be used as nitrogen sources. Purified PETN reductase was found to reduce TNT to its hydride-Meisenheimer complex, which was further reduced to the dihydride-Meisenheimer complex. Purified PETN reductase and recombinant Escherichia coli expressing PETN reductase were able to liberate nitrogen as nitrite from TNT. The ability to remove nitrogen from TNT suggests that PB2 or recombinant organisms expressing PETN reductase may be useful for bioremediation of TNT-contaminated soil and water. PMID:9687442

Kinetics and modeling of hexavalent chromium reduction in Enterobacter cloacae

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

Yamamoto, Koji; Kato, Junichi; Yano, Takuo

1993-01-05

Kinetics of bacterial reduction of toxic hexavalent chromium (chromate: CrO[sub 4][sup [minus]2]) was investigated using batch and fed-batch cultures of Enterobacter cloacae strain HO1. In fed-batch cultures, the CrO[sub 4][sup [minus]2] feed was controlled on the basis of the rate of pH change. This control strategy has proven to be useful for avoiding toxic CrO[sub 3][sup [minus]2] overload. A simple mathematical model was developed to describe the bacterial process of CrO[sub 4][sup [minus]2] reduction. In this model, two types of bacterial cells were considered: induced, CrO[sub 4][sup [minus]2]-resistant cells and uninduced, sensitive ones. Only resistant cells were assumed to bemore » able to reduce CrO[sub 4][sup [minus]2]. These fundamental ideas were supported by the model predictions which well approximated all experimental data. In a simulation study, the model was also used to optimize fed-batch cultures, instead of lengthy and expensive laboratory experiments.« less

Epidemiological typing of Enterobacter aerogenes.

PubMed Central

Gaston, M A; Strickland, M A; Ayling-Smith, B A; Pitt, T L

1989-01-01

The applicability of Enterobacter cloacae and Klebsiella typing reagents for classifying clinical strains of Enterobacter aerogenes was evaluated. Of 75 strains, none were agglutinated by E. cloacae O antisera or were sensitive to E. cloacae bacteriophages. In contrast, 70 strains reacted with Klebsiella capsular antisera. Two-thirds of the strains were lysed by Klebsiella typing phages. A set of five E. aerogenes bacteriocin producers classified 92% of strains into 15 sensitivity types. In conclusion, E. aerogenes may be typed with Klebsiella reagents, and the simple bacteriocin test provides further discrimination between strains. The limited number of capsular antigens in the species and their apparent similarity to Klebsiella capsular antigens warrant further investigation. PMID:2715326

Molecular and epidemiological characterization of IMP-type metallo-β-lactamase-producing Enterobacter cloacae in a Large tertiary care hospital in Japan.

PubMed

Hayakawa, Kayoko; Miyoshi-Akiyama, Tohru; Kirikae, Teruo; Nagamatsu, Maki; Shimada, Kayo; Mezaki, Kazuhisa; Sugiki, Yuko; Kuroda, Emi; Kubota, Shiho; Takeshita, Nozomi; Kutsuna, Satoshi; Tojo, Masayoshi; Ohmagari, Norio

2014-06-01

IMP-type metallo-β-lactamase enzymes have been reported in different geographical areas and in various Gram-negative bacteria. However, the risk factors and epidemiology pertaining to IMP-type metallo-β-lactamase-producing Enterobacter cloacae (IMP-producing E. cloacae) have not been systematically evaluated. We conducted a retrospective, matched case-control study of patients from whom IMP-producing E. cloacae isolates were obtained, in addition to performing thorough molecular analyses of the clinically obtained IMP-producing E. cloacae isolates. Unique cases with IMP-producing E. cloacae isolation were included. Patients with IMP-producing E. cloacae were matched to uninfected controls at a ratio of 1 to 3. Fifteen IMP-producing E. cloacae cases were identified, with five of the isolates being obtained from blood, and they were matched to 45 uninfected controls. All (100%) patients from whom IMP-producing E. cloacae isolates were obtained had indwelling devices at the time of isolation, compared with one (2.2%) uninfected control. Independent predictors for isolation of IMP-producing E. cloacae were identified as cephalosporin exposure and invasive procedures within 3 months. Although in-hospital mortality rates were similar between cases and controls (14.3% versus 13.3%), the in-hospital mortality of patients with IMP-producing E. cloacae-caused bacteremia was significantly higher (40%) than the rate in controls. IMP-producing E. cloacae isolates were frequently positive for other resistance determinants. The MICs of meropenem and imipenem were not elevated; 10 (67%) and 12 (80%) of the 15 IMP-producing E. cloacae isolates had a MIC of ≤ 1 μg/ml. A phylogenetic tree showed a close relationship among the IMP-producing E. cloacae samples. Indwelling devices, exposure to cephalosporin, and a history of invasive procedures were associated with isolation of IMP-producing E. cloacae. Screening for carbapenemase production is important in order to apply

Enterobacter cloacae with a novel variant of ACT AmpC beta-lactamase originating from glaucous gull (Larus hyperboreus) in Svalbard.

PubMed

Literak, Ivan; Manga, Ivan; Wojczulanis-Jakubas, Katarzyna; Chroma, Magdalena; Jamborova, Ivana; Dobiasova, Hana; Sedlakova, Miroslava Htoutou; Cizek, Alois

2014-07-16

We aimed at Escherichia coli and Enterobacter cloacae isolates resistant to cephalosporins and fluoroquinolones and Salmonella isolates in wild birds in Arctic Svalbard, Norway. Cloacal swabs of little auks (Alle alle, n=215) and samples of faeces of glaucous gulls (Larus hyperboreus, n=15) were examined. Inducible production of AmpC enzyme was detected in E. cloacae KW218 isolate. Sequence analysis of the 1146 bp PCR product of the ampC gene from this isolate revealed 99% sequence homology with the blaACT-14 and blaACT-5 AmpC beta-lactamase genes. Four, respectively six of the identified single nucleotide polymorphisms generated amino acid substitutions in the amino acid chain. As the ampC sequence polymorphism in the investigated E. cloacae strain was identified as unique, we revealed a novel variant of the ampC beta-lactamase gene blaACT-23. Copyright © 2014 Elsevier B.V. All rights reserved.

Efficacy of BRL 25000 against Serratia marcescens, Enterobacter cloacae, and Citrobacter freundii in urinary tract infections.

PubMed Central

Nakazawa, H; Hashimoto, T; Nishiura, T; Mitsuhashi, S

1983-01-01

Synergism between amoxicillin and clavulanic acid was not expected against cephalosporinase-producing bacterial strains because clavulanic acid has little inhibitory action on cephalosporinases. However, in a clinical trial of BRL 25000 (amoxicillin-clavulanic acid), excellent results were obtained in complicated urinary tract infections caused by Serratia marcescens, Enterobacter cloacae, and Citrobacter freundii strains which produced cephalosporinase and were highly resistant to amoxicillin alone. The good clinical efficacy of BRL 25000 in such urinary tract infections was probably due to the fact that the urinary concentration of clavulanic acid was higher than its minimal inhibitory concentrations for these strains. PMID:6357078

Aerobic degradation of 2,4,6-trinitrotoluene by Enterobacter cloacae PB2 and by pentaerythritol tetranitrate reductase

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

French, C.E.; Bruce, N.C.; Nicklin, S.

1998-08-01

Enterobacter cloacae PB2 was originally isolated on the basis of its ability to utilize nitrate esters, such as pentaerythritol tetranitrate (PETN) and glycerol trinitrate, as the sole nitrogen source for growth. The enzyme responsible is an NADPH-dependent reductase designated PETN reductase. E. cloacae PB2 was found to be capable of slow aerobic growth with 2,4,6-trinitrotoluene (TNT) as the sole nitrogen source. Dinitrotoluenes were not produced and could not be used as nitrogen sources. Purified PETN reductase was found to reduce TNT to its hydride-Meisenheimer complex, which was further reduced to the dihydride-Meisenheimer complex. Purified PETN reductase and recombinant Escherichia colimore » expressing PETN reductase were able to liberate nitrogen as nitrite from TNT. The ability to remove nitrogen from TNT suggests that PB2 or recombinant organisms expressing PETN reductase may be useful for bioremediation of TNT-contaminated soil and water.« less

Clonal Dissemination of Enterobacter cloacae Harboring blaKPC-3 in the Upper Midwestern United States

PubMed Central

Hargreaves, Melissa L.; Shaw, Kristin M.; Dobbins, Ginette; Snippes Vagnone, Paula M.; Harper, Jane E.; Boxrud, Dave; Lynfield, Ruth; Aziz, Maliha; Price, Lance B.; Silverstein, Kevin A. T.; Danzeisen, Jessica L.; Youmans, Bonnie; Case, Kyle; Sreevatsan, Srinand

2015-01-01

Carbapenemase-producing, carbapenem-resistant Enterobacteriaceae, or CP-CRE, are an emerging threat to human and animal health, because they are resistant to many of the last-line antimicrobials available for disease treatment. Carbapenemase-producing Enterobacter cloacae harboring blaKPC-3 recently was reported in the upper midwestern United States and implicated in a hospital outbreak in Fargo, North Dakota (L. M. Kiedrowski, D. M. Guerrero, F. Perez, R. A. Viau, L. J. Rojas, M. F. Mojica, S. D. Rudin, A. M. Hujer, S. H. Marshall, and R. A. Bonomo, Emerg Infect Dis 20:1583–1585, 2014, http://dx.doi.org/10.3201/eid2009.140344). In early 2009, the Minnesota Department of Health began collecting and screening CP-CRE from patients throughout Minnesota. Here, we analyzed a retrospective group of CP-E. cloacae isolates (n = 34) collected between 2009 and 2013. Whole-genome sequencing and analysis revealed that 32 of the strains were clonal, belonging to the ST171 clonal complex and differing collectively by 211 single-nucleotide polymorphisms, and it revealed a dynamic clone under positive selection. The phylogeography of these strains suggests that this clone existed in eastern North Dakota and western Minnesota prior to 2009 and subsequently was identified in the Minneapolis and St. Paul metropolitan area. All strains harbored identical IncFIA-like plasmids conferring a CP-CRE phenotype and an additional IncX3 plasmid. In a single patient with multiple isolates submitted over several months, we found evidence that these plasmids had transferred from the E. cloacae clone to an Escherichia coli ST131 bacterium, rendering it as a CP-CRE. The spread of this clone throughout the upper midwestern United States is unprecedented for E. cloacae and highlights the importance of continued surveillance to identify such threats to human health. PMID:26438492

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.

Recurrent FUO due to intermittent Enterobacter cloacae bacteremias from an infected pacemaker lead diagnosed by gallium scan.

PubMed

Cunha, Burke A; Jimada, Ismail

2018-01-01

Fever of unknown origin (FUO) refers to fevers of ≥101° F that persist for ≥3 weeks and remain undiagnosed after a focused inpatient or outpatient workup. FUO may be due to infectious, malignant/neoplastic, rheumatic/inflammatory, or miscellaneous disorders. Recurrent FUOs are due to the same causes of classical FUOs. Recurrent FUOs may have continuous or intermittent fevers and are particularly difficult to diagnose. With intermittent fever, recurrent FUO diagnostic tests are best obtained during fever episodes. With recurrent FUOs, the periodicity of febrile episodes is unpredictable. We present a case of a 70-year-old male who presented with recurrent FUO. Multiple extensive FUO workups failed to determine the source of his fever. During his last two episodes of fever/chills, blood cultures were positive for Enterobacter cloacae. Episodic E. cloacae bacteremias suggested a device-related infection, and the patient had a penile implant and permanent pacemaker (PPM). Following febrile episodes, he was treated with multiple courses of appropriate antibiotics, but subsequently fever/chills recurred. Since a device-associated infection was suspected, indium and PET scans were done, but were negative. The source of his intermittent E. cloacae bacteremias was finally demonstrated by gallium scan showing enhanced uptake on a cardiac lead, but not the penile implant or PPM. Gallium scanning remains useful in workup of FUOs, particularly when false-negative indium or PET scans are suspected. The involved pacemaker lead was explanted, grew E. cloacae and the patient has since remained fever free.

Characterization of the plant growth promoting bacterium, Enterobacter cloacae MSR1, isolated from roots of non-nodulating Medicago sativa

PubMed Central

Khalifa, Ashraf Y.Z.; Alsyeeh, Abdel-Moneium; Almalki, Mohammed A.; Saleh, Farag A.

2015-01-01

The aim of the present study was to characterize the endophytic bacterial strain designated MSR1 that was isolated from inside the non-nodulating roots of Medicago sativa after surface-sterilization. MSR1 was identified as Enterobacter cloacae using both 16S rDNA gene sequence analysis and API20E biochemical identification system (Biomerieux, France). Furthermore, this bacterium was characterized using API50CH kit (Biomerieux, France) and tested for antibacterial activities against some food borne pathogens. The results showed that E. cloacae consumed certain carbohydrates such as glycerol, d-xylose, d-maltose and esculin melibiose as a sole carbon source and certain amino acids such as arginine, tryptophan ornithine as nitrogen source. Furthermore, MSR1 possessed multiple plant-growth promoting characteristics; phosphate solubility, production of phytohormones acetoin and bioactive compounds. Inoculation of Pisum sativum with MSR1 significantly improved the growth parameters (the length and dry weight) of this economically important grain legume compared to the non-treated plants. To our knowledge, this is the first report addressing E. cloacae which exist in roots of alfalfa growing in Al-Ahsaa region. The results confirmed that E. cloacae exhibited traits for plant growth promoting and could be developed as an eco-friendly biofertilizer for P. sativum and probably for other important plant species in future. PMID:26858542

Improved antimicrobial activity of DU-6859a, a new fluoroquinolone, against quinolone-resistant Klebsiella pneumoniae and Enterobacter cloacae isolates with alterations in GyrA and ParC proteins.

PubMed Central

Deguchi, T; Yasuda, M; KawamuraT; Nakano, M; Ozeki, S; Kanematsu, E; Nishino, Y; Kawada, Y

1997-01-01

MICs of DU-6859a, a novel fluoroquinolone, for 18 Klebsiella pneumoniae isolates and 21 Enterobacter cloacae isolates with altered GyrA or altered GyrA and ParC ranged from < or =0.025 to 6.25 microg/ml and from 0.1 to 3.13 microg/ml, respectively. Based on the MICs at which 90% of the isolates were inhibited for these strains of K. pneumoniae and E. cloacae, DU-6859a exhibited 16- to 256-fold-greater activity than currently available fluoroquinolones. PMID:9371364

Improved antimicrobial activity of DU-6859a, a new fluoroquinolone, against quinolone-resistant Klebsiella pneumoniae and Enterobacter cloacae isolates with alterations in GyrA and ParC proteins.

PubMed

Deguchi, T; Yasuda, M; KawamuraT; Nakano, M; Ozeki, S; Kanematsu, E; Nishino, Y; Kawada, Y

1997-11-01

MICs of DU-6859a, a novel fluoroquinolone, for 18 Klebsiella pneumoniae isolates and 21 Enterobacter cloacae isolates with altered GyrA or altered GyrA and ParC ranged from < or =0.025 to 6.25 microg/ml and from 0.1 to 3.13 microg/ml, respectively. Based on the MICs at which 90% of the isolates were inhibited for these strains of K. pneumoniae and E. cloacae, DU-6859a exhibited 16- to 256-fold-greater activity than currently available fluoroquinolones.

Outbreak of IMI-1 Carbapenemase-producing colistin-resistant Enterobacter cloacae on the French island of Mayotte (Indian Ocean).

PubMed

Miltgen, Guillaume; Bonnin, Rémy A; Avril, Catherine; Benoit-Cattin, Thierry; Martak, Daniel; Leclaire, Alexandre; Traversier, Nicolas; Roquebert, Bénédicte; Jaffar-Bandjee, Marie-Christine; Lugagne, Nathalie; Filleul, Laurent; Subiros, Marion; de Montera, Anne-Marie; Cholley, Pascal; Thouverez, Michelle; Dortet, Laurent; Bertrand, Xavier; Naas, Thierry; Hocquet, Didier; Belmonte, Olivier

2018-05-25

The spread of carbapenemase-producing Enterobacteriaceae (CPE) in the Southwest Indian Ocean islands is poorly known. We describe here an outbreak of colistin-resistant Enterobacter cloacae harboring bla IMI-1 in the French overseas department of Mayotte. Between October 2015 and January 2017, all isolates of imipenem-non-susceptible E. cloacae at the Mayotte Medical Center and University Hospital of Reunion Island were screened for carbapenemase production. Positive isolates were typed by pulsed-field gel electrophoresis and WGS-based MLST and all β-lactamase genes identified by PCR and sequencing. The resistance profiles were determined by agar diffusion and E-tests. Genetic support of the bla IMI-1 gene was determined by WGS. We detected 18 isolates of E.cloacae harboring the bla IMI-1 gene in 17 patients from Mayotte. PFGE analysis showed 16 of the 18 strains to be clonally-related and belonging to sequence type ST820. Based on clinical data, this outbreak most likely had a community origin. The bla IMI-1 gene in the 18 isolates was carried by a new variant of an integrative mobile element involving the Xer recombinases, called EcloIMEX-8. The mcr-1 to mcr-5 genes were absent from the collection. These isolates belong to E. cloacae cluster XI, known to be colistin heteroresistant. We report here the first outbreak of IMI-1-producing Enterobacteriaceae. IMI-1 producers may be under-detected in microbiology laboratories because of their unusual antibiotic resistance profile (resistant to imipenem, but with intermediate resistance to ertapenem and susceptible to extended-spectrum cephalosporins) and the absence of bla IMI-1 in the panel of genes targeted by molecular diagnostic kits. Copyright © 2018. Published by Elsevier B.V.

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

Dominance of IMP-4-Producing Enterobacter cloacae among Carbapenemase-Producing Enterobacteriaceae in Australia

PubMed Central

Townell, Nicola; Nimmo, Graeme R.; George, Narelle M.; Robson, Jennifer; Vohra, Renu; Davis, Louise; Heney, Claire; Paterson, David L.

2015-01-01

The prevalence of carbapenemase-producing Enterobacteriaceae (CPE) has been increasing worldwide. blaIMP has been reported to be the predominant carbapenemase-encoding gene within Enterobacteriaceae in Australia. However, there are limited data currently available on CPE from Queensland, Australia. A total of 58 CPE isolates were isolated between July 2009 and March 2014 from Queensland hospitals. The clonality of isolates was determined by Diversilab repetitive sequence-based PCR. The isolates were investigated for the resistance mechanisms carbapenemase, extended-spectrum β-lactamase, and AmpC β-lactamase and for aminoglycoside resistance and plasmid-mediated quinolone resistance genes by PCR. The plasmid types associated with carbapenemase-encoding genes were characterized. The majority of the CPE were Enterobacter cloacae (n = 29). The majority of Queensland CPE isolates were IMP producers and comprised 11 species (n = 48). Nine NDM-producing Enterobacteriaceae were identified. One NDM-producing Klebsiella pneumoniae isolate coproduced OXA-48. One K. pneumoniae isolate was an OXA-181 producer. The incidence of IMP producers increased significantly in 2013. blaIMP-4 was found in all IMP-producing isolates. blaTEM, qnrB, and aacA4 were common among IMP-4 producers. The HI2 (67%) and L/M (21%) replicons were associated with blaIMP-4. All HI2 plasmids were of sequence type 1 (ST1). All but one of the NDM producers possessed blaCTX-M-15. The 16S rRNA methylase genes found among NDM producers were armA, rmtB, rmtC, and rmtF. The substantial increase in the prevalence of CPE in Queensland has been associated mainly with the emergence E. cloacae strains possessing HI2 plasmids carrying blaIMP-4 over the past 2 years. The importation of NDM producers and/or OXA-48-like producers in patients also contributed to the increased emergence of CPE. PMID:25918153

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

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)).

Se(VI) Reduction and the Precipitation of Se(0) Precipitation by the Facultative Bacterium Enterobacter Cloacae SLD1a-1 is Regulated by FNR

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

Yee,N.; Ma, J.; Dalia, A.

2007-01-01

The fate of selenium in the environment is controlled, in part, by microbial selenium oxyanion reduction and Se(0) precipitation. In this study, we identified a genetic regulator that controls selenate reductase activity in the Se-reducing bacterium Enterobacter cloacae SLD1a-1. Heterologous expression of the global anaerobic regulatory gene fnr (fumarate nitrate reduction regulator) from E. cloacae in the non-Se-reducing strain Escherichia coli S17-1 activated the ability to reduce Se(VI) and precipitate insoluble Se(0) particles. Se(VI) reduction by E. coli S17-1 containing the fnr gene occurred at rates similar to those for E. cloacae, with first-order reaction constants of k = 2.07more » x 10{sup -2} h{sup -1} and k = 3.36 x 10{sup -2} h{sup -1}, respectively, and produced elemental selenium particles with identical morphologies and short-range atomic orders. Mutation of the fnr gene in E. cloacae SLD1a-1 resulted in derivative strains that were deficient in selenate reductase activity and unable to precipitate elemental selenium. Complementation by the wild-type fnr sequence restored the ability of mutant strains to reduce Se(VI). Our findings suggest that Se(VI) reduction and the precipitation of Se(0) by facultative anaerobes are regulated by oxygen-sensing transcription factors and occur under suboxic conditions.« less

Synthesis of novel galactose containing chemicals by beta-galactosidase from Enterobacter cloacae B5.

PubMed

Lu, Lili; Xu, Xiaodong; Gu, Guofeng; Jin, Lan; Xiao, Min; Wang, Fengshan

2010-09-01

The beta-galactosidase from Enterobacter cloacae B5 was employed to synthesize novel galactose containing chemicals (GCCs) using mannitol, sorbose, and salicin as acceptors in the presence of o-nitrophenyl-beta-d-galactopyranoside (oNPGal) as donor. The influences of the process parameters on GCC synthesis using mannitol as an acceptor, including effects of variations in initial substrate concentration, reaction time, and temperature, were studied in detail. The mannitol derivative reached a yield of 14.6% when the enzyme was used in the presence of 30 mM oNPGal and 60mM mannitol at 50 degrees C for 10 min. The sorbose and salicin derivatives reached yields of 19.4% and 25.2%, respectively, under the same conditions except for acceptor concentrations. Through analysis of ESI-MS and NMR spectroscopy, the three derivatives were identified to be beta-D-galactopyranosyl-(1-->1')-D-mannitol, beta-D-galactopyranosyl-(1-->1')-l-sorbose, and 2-(hydroxymethyl) phenyl beta-D-galactopyranosyl-(1-->6')-beta-D-glucopyranoside. (c) 2010 Elsevier Ltd. All rights reserved.

Cefepime and amikacin synergy in vitro and in vivo against a ceftazidime-resistant strain of Enterobacter cloacae.

PubMed

Mimoz, O; Jacolot, A; Padoin, C; Tod, M; Samii, K; Petitjean, O

1998-03-01

The activities of cefepime and amikacin alone or in combination against an isogenic pair of Enterobacter cloacae strains (wild type and stably derepressed, ceftazidime-resistant mutant) were compared using an experimental model of pneumonia in non-leucopenic rats. Animals were infected by administering 8.4 log10 cfu of E. cloacae intratracheally, and therapy was initiated 12 h later. At that time, the animals' lungs showed bilateral pneumonia and contained more than 7 log10 E. cloacae cfu/g tissue. Because rats eliminate amikacin and cefepime much more rapidly than humans, renal impairment was induced in all animals to simulate the pharmacokinetic parameters of humans. In-vitro susceptibilities showed an inoculum effect with cefepime proportional to the bacterial titre against the two strains, but more pronounced with the stably derepressed mutant strain, whereas with bacterial concentrations of up to 7 log10 cfu/mL, no inoculum effect was observed with amikacin. In-vitro killing indicated that antibiotic combinations were synergic only at intermediate concentrations. At peak concentrations, the combination was merely as effective as amikacin alone. At trough concentrations, a non-significant trend towards the superiority of the combination over each antibiotic alone was noted. Moreover, cefepime was either bacteriostatic or permitted regrowth of the organisms in the range of antibiotic concentrations tested. Although each antibiotic alone failed to decrease bacterial counts in the lungs, regardless of the susceptibility of the strain used, the combination of both antibiotics was synergic and induced a significant decrease in the lung bacterial count 24 h after starting therapy when compared with tissue bacterial numbers in untreated animals or animals treated with either antibiotic alone. No resistant clones emerged during treatment with any of the antibiotic regimens studied.

Harnessing the bio-mineralization ability of urease producing Serratia marcescens and Enterobacter cloacae EMB19 for remediation of heavy metal cadmium (II).

PubMed

Bhattacharya, Amrik; Naik, S N; Khare, S K

2018-06-01

In the present study, urease positive Serratia marcescens (NCIM2919) and Enterobacter cloacae EMB19 (MTCC10649) were individually evaluated for remediation of cadmium (II) using ureolysis-induced calcium carbonate precipitation. Both the cultures were observed to efficiently remove cadmium from the media through co-precipitation of Cd (II) and Ca (II). S. marcescens and E. cloacae EMB19, respectively showed 96 and 98% removal of initial 5.0 mg L -1 soluble Cd (II) from the urea and CaCl 2 laden media at 96 h of incubation period. At higher Cd (II) concentrations of 10 and 15 mg L -1 , cadmium removal efficiency was much higher in case of E. cloacae EMB19 compared to S. marcescens. In-vitro cadmium (II) remediation study using urease containing cell-free culture supernatant of S. marcescens and E. cloacae EMB19 showed respective 98 and 53% removal of initial 50 mg L -1  Cd (II) from the reaction mixtures in co-presence of Ca (II). While in sole presence of Cd (II), only 16 and 8% removal of Cd (II) were detected for S. marcescens and E. cloacae EMB19, respectively. The elemental analysis of the co-precipitated mineral products using Energy Dispersive X-ray spectroscopy (EDX) clearly showed the prevalence of Ca and Cd ions. The morphology Cd-Ca composites formed with respect to both the cultures were observed to be of different shape and size as revealed through Scanning Electron Microscopy (SEM). Entire study hence comes out with a sustainable bioremediation option which could be effectively used to tackle Cd (II) or other heavy metal pollution. Copyright © 2018 Elsevier Ltd. All rights reserved.

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)).

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.

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

MALDI-TOF MS as a Tool To Detect a Nosocomial Outbreak of Extended-Spectrum-β-Lactamase- and ArmA Methyltransferase-Producing Enterobacter cloacae Clinical Isolates in Algeria

PubMed Central

Khennouchi, Nour Chems el Houda; Loucif, Lotfi; Boutefnouchet, Nafissa; Allag, Hamoudi

2015-01-01

Enterobacter cloacae is among the most important pathogens responsible for nosocomial infections and outbreaks. In this study, 77 Enterobacter isolates were collected: 27 isolates from Algerian hospitals (in Constantine, Annaba, and Skikda) and 50 isolates from Marseille, France. All strains were identified by matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS). Antibiotic susceptibility testing was performed by the disk diffusion method. PCR was used to detect extended-spectrum-beta-lactamase (ESBL)-encoding, fluoroquinolone resistance-encoding, and aminoglycoside-modifying enzyme (AME) genes. Epidemiological typing was performed using MALDI-TOF MS with data mining approaches, along with multilocus sequence typing (MLST). Sixty-eight isolates (27 from Algeria, 41 from Marseille) were identified by MALDI-TOF MS as E. cloacae. Resistance to antibiotics in the Algerian isolates was significantly higher than that in the strains from Marseille, especially for beta-lactams and aminoglycosides. Eighteen of the 27 Algerian isolates and 11 of the 41 Marseille isolates possessed at least one ESBL-encoding gene: blaCTX-M and/or blaTEM. AME genes were detected in 20 of the 27 Algerian isolates and 8 of the 41 Marseille isolates [ant(2″)-Ia, aac(6′)-Ib-cr, aadA1, aadA2, and armA]. Conjugation experiments showed that armA was carried on a transferable plasmid. MALDI-TOF typing showed three separate clusters according to the geographical distribution and species level. An MLST-based phylogenetic tree showed a clade of 14 E. cloacae isolates from a urology unit clustering together in the MALDI-TOF dendrogram, suggesting the occurrence of an outbreak in this unit. In conclusion, the ability of MALDI-TOF to biotype strains was confirmed, and surveillance measures should be implemented, especially for Algerian patients hospitalized in France. PMID:26239991

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

Structure-Function Studies of Ser-289 in the Class C β-Lactamase from Enterobacter cloacae P99

PubMed Central

Trépanier, Sonia; Knox, James R.; Clairoux, Natalie; Sanschagrin, François; Levesque, Roger C.; Huletsky, Ann

1999-01-01

Site-directed mutagenesis of Ser-289 of the class C β-lactamase from Enterobacter cloacae P99 was performed to investigate the role of this residue in β-lactam hydrolysis. This amino acid lies near the active site of the enzyme, where it can interact with the C-3 substituent of cephalosporins. Kinetic analysis of six mutant β-lactamases with five cephalosporins showed that Ser-289 can be substituted by amino acids with nonpolar or polar uncharged side chains without altering the catalytic efficiency of the enzyme. These data suggest that Ser-289 is not essential in the binding or hydrolytic mechanism of AmpC β-lactamase. However, replacement by Lys or Arg decreased by two- to threefold the kcat of four of the five β-lactams tested, particularly cefoperazone, cephaloridine, and cephalothin. Three-dimensional models of the mutant β-lactamases revealed that the length and positive charge of the side chain of Lys and Arg could create an electrostatic linkage to the C-4 carboxylic acid group of the dihydrothiazine ring of the acyl intermediate which could slow the deacylation step or hinder release of the product. PMID:10049265

KPC-4 Is Encoded within a Truncated Tn4401 in an IncL/M Plasmid, pNE1280, Isolated from Enterobacter cloacae and Serratia marcescens

PubMed Central

Bryant, Kendall A.; Van Schooneveld, Trevor C.; Thapa, Ishwor; Bastola, Dhundy; Williams, Laurina O.; Safranek, Thomas J.; Hinrichs, Steven H.; Rupp, Mark E.

2013-01-01

We describe the transfer of blaKPC-4 from Enterobacter cloacae to Serratia marcescens in a single patient. DNA sequencing revealed that KPC-4 was encoded on an IncL/M plasmid, pNE1280, closely related to pCTX-M360. Further analysis found that KPC-4 was encoded within a novel Tn4401 element (Tn4401f) containing a truncated tnpA and lacking tnpR, ISKpn7 left, and Tn4401 IRL-1, which are conserved in other Tn4401 transposons. This study highlights the continued evolution of Tn4401 transposons and movement to multiple plasmid backbones that results in acquisition by multiple species of Gram-negative bacilli. PMID:23070154

New Monoclonal Antibodies against a Novel Subtype of Shiga Toxin 1 Produced by Enterobacter cloacae and Their Use in Analysis of Human Serum

PubMed Central

Skinner, Craig; Patfield, Stephanie; Khalil, Rowaida; Kong, Qiulian

2016-01-01

ABSTRACT Shiga toxin (Stx) is a major virulence factor of several bacterial pathogens that cause potentially fatal illness, including Escherichia coli and Shigella spp. The continual emergence of new subtypes of Stxs presents challenges for the clinical diagnosis of infections caused by Stx-producing organisms. Here, we report the development of four new monoclonal antibodies (MAbs) against Stx1e, a novel subtype of Stx1 that was produced by an Enterobacter cloacae strain and had limited reactivity with existing anti-Stx1 antibodies. Western blot analysis indicates that these MAbs were Stx1 specific, bound to the A subunit, and had distinct preferences for subtypes of Stx1. Of the four MAbs, Stx1e-2 was capable of partially neutralizing cytotoxicities derived from Stx1e in Vero cells. Enzyme-linked immunosorbent assays assembled with these high-affinity MAbs detected Stx1e at concentrations as low as 4.8 pg/ml in phosphate-buffered saline and 53.6 pg/ml in spiked human serum samples and were also capable of distinguishing Stx1e-producing strains in enriched cultures. These assays may therefore have clinical value in diagnosing Stx1e-producing bacterial infection. Additionally, characteristics of Stx1e, such as the origin of stx1e genes, conditions for toxin expression, receptor binding, and cytotoxicity, were investigated with the new antibodies developed in this study. This information should be useful for further understanding the clinical significance and prevalence of Stx1e-harboring E. cloacae and other organisms. IMPORTANCE Stxs are among the most clinically important virulence factors of Shigella and enterohemorrhagic Escherichia coli. There are many varieties of Stx, and although Stx1a and Stx2a are the most common and widely distributed types of Stx, new variants of Stx are continually emerging. These new variants of Stx can be challenging to detect, since most Stx detection kits are optimized for the detection of Stx1a and Stx2a. Stx1e, recently

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

Synergistic activity and mechanism of action of ceftazidime and apigenin combination against ceftazidime-resistant Enterobacter cloacae.

PubMed

Eumkeb, Griangsak; Chukrathok, Somnuk

2013-02-15

The purpose of this investigation was to examine the antibacterial and synergistic effect of naturally occurring flavonoids, apigenin, quercetin, naringenin and ceftazidime when use singly and in combination against ceftazidime-resistant Enterobacter cloacae strains by minimum inhibitory concentration (MIC), checkerboard and viable count methods. The mode of actions were also studied by electronmicoscopy, enzyme assay, outer and inner membrane permeabilisation. The results showed that these strains were positive in the ESBL-ampC genes combination by multiplex PCR. These findings were confirmed by MICs that these strains were resistant to ceftazidime, cefepime and flomoxef at >1024, 16-24, >256 μg/ml respectively, while susceptible to imipenem at 1-2 μg/ml. The synergistic activity was observed at ceftazidime plus either apigenin or naringenin combinations with FIC indixes between <0.01 and <0.27 against these strains, whereas ceftazidime plus clavulanic acid or quercetin did not exhibit synergy. The modulation of ceftazidime-resistance by apigenin or narigenin significantly enhanced the activities of ceftazidime. The 5,7-OH group of A ring and one 4'-OH group of the B ring in apigenin and naringenin are important for synergistic activity. Viable counts showed that the killing of ceftazidime-resistant E. cloacae DMST 21394 (CREC) cells by 3 μg/ml ceftazidime was potentiated by 3 μg/ml apigenin to low levels (10(3) cfu/ml) over 6h. Electronmicroscopy clearly showed that ceftazidime 3 μg/ml in combination with 3 μg/ml of apigenin also caused marked morphological damage of cell wall, cell shape and plasma membrane of this strain. Enzymes assays indicated that apigenin showed marked inhibitory activity against penicillinase type IV from E. cloacae. The results for outer membrane (OM) permeabilization in both nitrocefin (NCF) assay and crystal violet uptake showed that the combination of ceftazidime plus apigenin significantly altered OM permeabilisation of CREC

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.

Bacillus subtilis and Enterobacter cloacae endophytes from healthy Theobroma cacao L. trees can systemically colonize seedlings and promote growth.

PubMed

Leite, Hianna Almeida Câmara; Silva, Anderson Barbosa; Gomes, Fábio Pinto; Gramacho, Karina Peres; Faria, José Cláudio; de Souza, Jorge Teodoro; Loguercio, Leandro Lopes

2013-03-01

Clonal genotypes resistant to fungal diseases are an important component of the cocoa production system in southeastern Bahia state (Brazil), so that technologies for faster production of stronger and healthier plantlets are highly desirable. In this study, the effects of inoculated bacterial endophytes isolated from healthy adult cacao plants on seedlings, and aspects related to inoculation methods, colonization patterns, and photosynthesis were investigated. Sequencing of 16S rRNA, hsp-60, and rpo-B genes placed the wild-type isolates within the species Enterobacter cloacae (isolates 341 and 344) and Bacillus subtilis (isolate 629). Spontaneous rifampicin-resistant (rif(R)) variants for 344 were also produced and tested. Endophytic application was either by immersion of surface sterilized seeds in bacterial suspensions or direct inoculation into soil, 20 days after planting non-inoculated seeds into pots. Results from in vitro recovery of inoculated isolates showed that the wild-type endophytes and rif(R) variants systemically colonized the entire cacao seedlings in 15-20 days, regardless of the inoculation method. Some endophytic treatments showed significant increases in seedlings' height, number of leaves, and dry matter. Inoculation methods affected the combined application of endophytes, which maintained the growth-promotion effects, but not in the same manner as in single applications. Interestingly, the 344-3.2 rif(R) variant showed improved performance in relation to both the wild type and another related variant. Photosynthetic rates and stomatal conductance increased significantly for some endophytic treatments, being partially associated with effects on growth and affected by the inoculation method. The results suggest that E. cloacae and B. subtilis endophytes from healthy adult plants (not transmitted by seeds) were able to promote vegetative growth on cacao seedlings. The development of products for large-scale use in seedlings

Bioremoval of lead using Pennisetum purpureum augmented with Enterobacter cloacae-VITPASJ1: A pot culture approach.

PubMed

Das, Anamika; Belgaonkar, Priyanka; Raman, Aditya S; Banu, Sofia; Osborne, Jabez W

2017-06-01

Lead is a toxic heavy metal discharged into the ecosystem from various industries. Biological remediation strategies have been effective in the bioremoval of lead. In our current study, a phytobacterial system using Pennisetum purpureum along with lead-resistant bacterium (LRB) was employed for the uptake of lead. The LRB was obtained from lead-contaminated sites. The isolate VITPASJ1 was found to be highly tolerant to lead and was identified as an effective plant growth-promoting bacterium. The 16S rRNA sequencing revealed VITPASJ1 to be the closest neighbour of Enterobacter cloacae. The lead-resistant gene pbrA in the plant and the bacterium were amplified using a specific primer. The uptake of lead was studied by phytoremediation and rhizoremediation set-ups where the soil was supplemented with various concentrations of lead (50, 100, 150 mg/kg). The plants were uprooted at regular intervals, and the translocation of lead into the plant was determined by atomic absorption spectroscopy. The root length, shoot height and chlorophyll content were found to be higher in the rhizoremediation set-up when compared to the phytoremediation set-up. The scanning electron microscopic micrographs gave a clear picture of increased tissue damage in the root and shoot of the phytoremediation set-up as compared to the rhizoremediation set-up with LRB.

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

Osteoarticular Infections Following Open or Penetrating Trauma in Children in the Post-Community-Acquired Methicillin-Resistant Staphylococcus aureus Era: The Impact of Enterobacter cloacae.

PubMed

McNeil, J Chase; Vallejo, Jesus G; Hulten, Kristina G; Kaplan, Sheldon L

2018-03-21

Most cases of pediatric osteoarticular infections (OAI) are hematogenous in nature and caused by Staphylococcus aureus. OAI in children can also occur through direct inoculation of microorganisms secondary to penetrating or open trauma. No studies in the US have evaluated the microbiology or outcomes of trauma-related OAI (TROAI) in children in the era of community-acquired MRSA (CA-MRSA). Cases were identified from the inpatient infectious diseases consultation database at Texas Children's Hospital from Jan 2011-Dec 2016. TROAI cases were those in which OAI developed following a clear history of penetrating trauma, open fracture, crush injury or traumatic amputation. Only cases with radiographic evidence of bone abscess, gross appearance of infection at time of surgery and/or positive cultures from bone or joint were included. Complications included recurrence of infection, pathologic fracture or chronic osteomyelitis. During the study period, 692 consultations for OAI were performed, with 34 meeting inclusion criteria. In 68% at least one organism was isolated and the most commonly isolated organisms were S. aureus (32% overall, 21% MRSA) and Enterobacter cloacae (24%). Polymicrobial infections occurred in 38% of patients. 85% of patients had at least one surgical procedure and 38% underwent ≥2 procedures. 82% of patients were discharged on oral therapy. Complications developed in 15% of patients and were more commonly associated with E. cloacae (80% vs. 14%, p=0.007) and fungi (p=0.03). TROAI are relatively uncommon in children but cause significant morbidity. While MRSA contributes substantially to TROAI, the highly diverse microbiology emphasizes the importance of obtaining cultures for microbiologic diagnosis and management. Clinicians should be aware of the frequency of E. cloacae in TROAI and its high risk for sequelae.

Phage-mediated Shiga toxin (Stx) horizontal gene transfer and expression in non-Shiga toxigenic Enterobacter and Escherichia coli strains

USDA-ARS?s Scientific Manuscript database

M12X01451, an Enterobacter cloacae strain recently identified from a clinical specimen, produces a new Stx1e that was not neutralized by existing anti-Stx1 monoclonal antibodies. Acquisition of stx by Ent. cloacae is rare and information regarding the origin and stability of the stx1e in M12X01451 i...

Validation of the Accuracy and Reliability of Culturing Intravascular Catheter Segments

DTIC Science & Technology

1992-11-24

Pseudomonas aeruginosa 2 2 - Staphylococcus haemolyticus 2 2 - Other:(Bacillus spp.(1), 7 4 - Enterobacter Cloacae(l), Beta-strep(2), Staph spp.(3) (not further identified)) 20 ...tabulation, each organism from multiply colonized catheters was designated separately. Coagulase negative staphylococcus was the most commonly isolated... staphylococcus (10 of 21 organisms). Bedside plated cultures identified infection with yeast (2), pseudomonas aeruginosa (2), staphylococcus aureus

Analysis of etiology and drug resistance of biliary infections.

PubMed

Wang, Xin; Li, Qiu; Zou, Shengquan; Sun, Ziyong; Zhu, Feng

2004-01-01

The bile was collected from fro patients with biliary infections, with the bacterium isolated to study the sensitivity of each kind of the bacterium to several antibiotics in common use. Except G- bacterium, we also found some kinds of G+ bacterium in infection bile. G- bacterium were not sensitive to Clindamycin, G+ bacterium were sensitive to Ciprofloxacin. Escherichia coli, Xanthomonas maltophilia, Enterobacter cloacae, Pseudomonas aeruginosa were sensitive to Ampicillin. G+ bacterium were not sensitive to Azactam. Enterococcus faecalis, Enterococcus faecium, Enterobacter cloacae were not sensitive to Ceftazidime. Enterococcus faecalis, Staphylococcus coagulase negative, Staphylococcus epidermidis, Pseudomonas aeruginosa were not sensitive to Ceftriaxone Sodium. We didn't found any bacterium resistance Imipenem. The possibility of the existence of G+ bacterium as well as drug resistance should be considered n patients with biliary infections. The value of susceptibility test should be respected to avoid drug abuse of antibiotics.

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

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

Biological characterization of lead-enhanced exopolysaccharide produced by a lead resistant Enterobacter cloacae strain P2B.

PubMed

Naik, Milind Mohan; Pandey, Anju; Dubey, Santosh Kumar

2012-09-01

A lead resistant bacterial strain isolated from effluent of lead battery manufacturing company of Goa, India has been identified as Enterobacter cloacae strain P2B based on morphological, biochemical characters, FAME profile and 16S rDNA sequence data. This bacterial strain could resist lead nitrate up to 1.6 mM. Significant increase in exopolysaccharide (EPS) production was observed as the production increased from 28 to 108 mg/L dry weight when exposed to 1.6 mM lead nitrate in Tris buffered minimal medium. Fourier-transformed infrared spectroscopy of this EPS revealed presence of several functional groups involved in metal binding viz. carboxyl, hydroxyl and amide groups along with glucuronic acid. Gas chromatography coupled with mass spectrometry analysis of alditol-acetate derivatives of acid hydrolysed EPS produced in presence of 1.6 mM lead nitrate demonstrated presence of several neutral sugars such as rhamnose, arabinose, xylose, mannose, galactose and glucose, which contribute to lead binding hydroxyl groups. Scanning electron microscope coupled with energy dispersive X-ray spectrometric analysis of this lead resistant strain exposed to 1.6 mM lead nitrate interestingly revealed mucous EPS surrounding bacterial cells which sequestered 17 % lead (as weight %) extracellularly and protected the bacterial cells from toxic effects of lead. This lead resistant strain also showed multidrug resistance. Thus these results significantly contribute to better understanding of structure, function and environmental application of lead-enhanced EPSs produced by bacteria. This lead-enhanced biopolymer can play a very important role in bioremediation of several heavy metals including lead.

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.

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

Antibacterial activity of Zuccagnia punctata Cav. ethanolic extracts.

PubMed

Zampini, Iris C; Vattuone, Marta A; Isla, Maria I

2005-12-01

The present study was conducted to investigate antibacterial activity of Zuccagnia punctata ethanolic extract against 47 strains of antibiotic-resistant Gram-negative bacteria and to identify bioactive compounds. Inhibition of bacterial growth was investigated using agar diffusion, agar macrodilution, broth microdilution and bioautographic methods. Zuccagnia punctata extract was active against all assayed bacteria (Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Enterobacter cloacae, Serratia marcescens, Morganella morganii, Acinetobacter baumannii, Pseudomonas aeruginosa, Stenotrophomonas maltophilia) with minimal inhibitory concentration (MIC) values ranging from 25 to 200 microg/mL. Minimal bactericidal concentration (MBC) values were identical or two-fold higher than the corresponding MIC values. Contact bioautography, indicated that Zuccagnia punctata extracts possess one major antibacterial component against Pseudomonas aeruginosa and at least three components against. Klebsiella pneumoniae and Escherichia coli. Activity-guided fractionation of 1he ethanol extract on a silica gel column yielded a compound (2',4'-dihydroxychalcone), which exhibited strong antibacterial activity with MIC values between 0.10 and 1.00 microg/mL for Proteus mirabilis, Enterobacter cloacae, Serratia marcescens, Morganella morganii, Acinetobacter baumannii, Pseudomonas aeruginosa, Stenotrophomonas maltophilia. These values are lower than imipenem (0.25-16 microg/mL). Zuccagnia punctata might provide promising therapeutic agents against infections with multi-resistant Gram-negative bacteria.

Enterobacter cloacae as biosurfactant producing bacterium: differentiating its effects on interfacial tension and wettability alteration Mechanisms for oil recovery during MEOR process.

PubMed

Sarafzadeh, Pegah; Hezave, Ali Zeinolabedini; Ravanbakhsh, Moosa; Niazi, Ali; Ayatollahi, Shahab

2013-05-01

Microbial enhanced oil recovery (MEOR) process utilizes microorganisms or their metabolites to mobilize the trapped oil in the oil formation after primary and secondary oil recovery stages. MEOR technique is considered as more environmentally friendly and low cost process. There are several identified mechanisms for more oil recovery using MEOR processes however; wettability alteration and interfacial tension (IFT) reduction are the important ones. Enterobacter Cloacae, a facultative bio-surfactant producer bacterium, was selected as a bacterial formulation due to its known performance on IFT reduction and wettability alteration. To quantify the effects of these two mechanisms, different tests including oil spreading, in situ and ex situ core flooding, wettability measurement (Amott), IFT, viscosity and pH measurements were performed. The obtained results revealed that the experimental procedure used in this study was able to quantitatively identify the individual effects of both mechanisms on the ultimate microbial oil recovery. The results demonstrated considerable effects of both mechanisms on the tertiary oil recovery; however after a proper shut in time period, more tertiary oil was recovered because of wettability alteration mechanism. Finally, SEM images taken from the treated cores showed biofilm formation on the rock pore surfaces, which is responsible for rock surface wettability alteration. Copyright © 2013 Elsevier B.V. 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.

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).

[Combined effect of sulbactam/cefoperazone and other antibiotics against clinical isolates of multi-resistant strains. II. In vitro combined effects of sulbactam/cefoperazone with imipenem/cilastatin, cefuzonam, flomoxef, amikacin or tobramycin].

PubMed

Kouda, M; Kumagai, I; Kobayashi, J; Sugai, R; Matsuzaki, H

1991-02-01

We evaluated combined effects of sulbactam/cefoperazone (SBT/CPZ) with each of imipenem/cilastatin (IPM), cefuzonam, flomoxef, amikacin (AMK) and tobramycin (TOB) against 324 clinical strains. Through this study, we obtained the following results. 1. Against Serratia marcescens and Enterobacter cloacae, good synergism was obtained by combining SBT/CPZ with IPM, AMK, or TOB. 2. Against Pseudomonas aeruginosa, good synergism was obtained by combining SBT/CPZ with AMK or TOB. 3. When SBT/CPZ was used in combination with IPM, antagonism was observed among about 45% of strains of P. aeruginosa.

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

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.

In vitro antibacterial activity and beta-lactamase stability of CP-70,429 a new penem antibiotic.

PubMed

Minamimura, M; Taniyama, Y; Inoue, E; Mitsuhashi, S

1993-07-01

In in vitro susceptibility tests, the new penem CP-70,429 showed potent antibacterial activity against gram-positive and gram-negative bacteria except Pseudomonas aeruginosa and Xanthomonas maltophilia. CP-70,429 was stable to various types of beta-lactamases except for the enzyme from X. maltophilia and was 16- to 128-fold more active than the other compounds against beta-lactamase-producing strains of Enterobacter cloacae and Citrobacter freundii.

In vitro antibacterial activity and beta-lactamase stability of CP-70,429 a new penem antibiotic.

PubMed Central

Minamimura, M; Taniyama, Y; Inoue, E; Mitsuhashi, S

1993-01-01

In in vitro susceptibility tests, the new penem CP-70,429 showed potent antibacterial activity against gram-positive and gram-negative bacteria except Pseudomonas aeruginosa and Xanthomonas maltophilia. CP-70,429 was stable to various types of beta-lactamases except for the enzyme from X. maltophilia and was 16- to 128-fold more active than the other compounds against beta-lactamase-producing strains of Enterobacter cloacae and Citrobacter freundii. PMID:8363389

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.

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.

Draft Genome Sequences of Pseudomonas aeruginosa Isolates from Wounded Military Personnel.

PubMed

Arivett, Brock A; Ream, Dave C; Fiester, Steven E; Kidane, Destaalem; Actis, Luis A

2016-08-11

Pseudomonas aeruginosa, a Gram-negative bacterium that causes severe hospital-acquired infections, is grouped as an ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) pathogen because of its extensive drug resistance phenotypes and effects on human health worldwide. Five multidrug resistant P. aeruginosa strains isolated from wounded military personnel were sequenced and annotated in this work. Copyright © 2016 Arivett et al.

Chemical compositions and antibacterial activities of the essential oils from aerial parts and corollas of Origanum acutidens (Hand.-Mazz.) Ietswaart, an endemic species to Turkey.

PubMed

Cosge, Belgin; Turker, Arzu; Ipek, Arif; Gurbuz, Bilal

2009-04-30

Essential oils extracted by hydrodistillation from the aerial parts and corollas of Origanum acutidens (Hand.-Mazz.) Ietswaart, an endemic Turkish flora species, were analyzed by GC-MS. The amounts of essential oil obtained from the aerial parts and the corollas were 0.73% and 0.93%, respectively. Twenty-five components in both the aerial parts oil and the corolla oil, representing 95.11% and 93.88%, respectively, were identified. The aerial parts and corolla oils were characterized by the predominance of two components: p-cymene (9.43% and 17.51%) and carvacrol (67.51% and 52.33%), respectively. The essential oils were also evaluated for their antimicrobial activity against ten bacteria by the disc diffusion assay. Our findings showed the following order in the sensitivity to the essential oils, as indicated by the corresponding inhibition zones: Proteus vulgaris > Salmonella typhimurium > Enterobacter cloacae > Klebsiella pneumonia > Escherichia coli > Serratia marcescens > Pseudomonas aeruginosa for the aerial parts essential oil, and Salmonella typhimurium > Proteus vulgaris > Enterobacter cloacae > Escherichia coli > Klebsiella pneumoniae > Serratia marcescens > Pseudomonas aeruginosa for the corolla essential oil. The studied essential oils thus exhibited a broad-spectrum of activity against both Gram-positive and Gram-negative bacteria, whereas the tested Gram-positive bacteria were more susceptible to the essential oil samples.

Pathology of cloaca anomalies with case correlation.

PubMed

Gupta, Anita; Bischoff, Andrea

2016-04-01

During the fourth week of human embryo development, a transient common channel known as a cloaca is formed from which three cavities with three external orifices arises. Cloaca anomalies occur when there is failure of separation of the rectum, vagina, and urethra channel resulting in a single drain into the perineum. In our previous institutional studies, Runck et al. compared human and mouse cloaca development and found early mis-patterning of the embryonic cloaca deranged hedgehog and bone morphogenetic proteins (BMP) signaling. Also, our group reported the embryological correlation of the epithelial and stromal histology found in step sections of the common channel in 14 cloaca malformations in humans. In this review, we present the pathology of a 4-year-old female with a cloaca and VACTERL complex, and summarize our current knowledge of cloaca pathology. Furthermore, we suggest that careful pathological examination of cloaca specimens in conjunction with surgical orientation may result in a better understanding of the etiology of this condition. Published by Elsevier Inc.

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.

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.

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.

Evaluation of High-Resolution Melting Curve Analysis of Ligation-Mediated Real-Time PCR, a Rapid Method for Epidemiological Typing of ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter Species) Pathogens

PubMed Central

Ryberg, Anna; Billström, Hanna; Hällgren, Anita; Nilsson, Lennart E.; Marklund, Britt-Inger; Olsson-Liljequist, Barbro; Schön, Thomas

2014-01-01

A single-tube method, ligation-mediated real-time PCR high-resolution melt analysis (LMqPCR HRMA), was modified for the rapid typing of Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp. (ESKAPE) pathogens. A 97% agreement (60/62 isolates) was achieved in comparison to pulsed-field gel electrophoresis (PFGE) results, which indicates that LMqPCR HRMA is a rapid and accurate screening tool for monitoring nosocomial outbreaks. PMID:25232168

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

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

Biochemical Characterization of CTX-M-15 from Enterobacter cloacae and Designing a Novel Non-β-Lactam-β-Lactamase Inhibitor

PubMed Central

Danishuddin, Mohd; Khan, Asad U.

2013-01-01

The worldwide dissemination of CTX-M type β-lactamases is a threat to human health. Previously, we have reported the spread of bla CTX-M-15 gene in different clinical strains of Enterobacteriaceae from the hospital settings of Aligarh in north India. In view of the varying resistance pattern against cephalosporins and other β-lactam antibiotics, we intended to understand the correlation between MICs and catalytic activity of CTX-M-15. In this study, steady-state kinetic parameters and MICs were determined on E. coli DH5α transformed with bla CTX-M-15 gene that was cloned from Enterobacter cloacae (EC-15) strain of clinical background. The effect of conventional β-lactamase inhibitors (clavulanic acid, sulbactam and tazobactam) on CTX-M-15 was also studied. We have found that tazobactam is the best among these inhibitors against CTX-M-15. The inhibition characteristic of tazobactam is defined by its very low IC50 value (6 nM), high affinity (K i = 0.017 µM) and better acylation efficiency (k +2/K′ = 0.44 µM−1s−1). It forms an acyl-enzyme covalent complex, which is quite stable (k +3 = 0.0057 s−1). Since increasing resistance has been reported against conventional β-lactam antibiotic-inhibitor combinations, we aspire to design a non-β-lactam core containing β-lactamase inhibitor. For this, we screened ZINC database and performed molecular docking to identify a potential non-β-lactam based inhibitor (ZINC03787097). The MICs of cephalosporin antibiotics in combination with this inhibitor gave promising results. Steady-state kinetics and molecular docking studies showed that ZINC03787097 is a reversible inhibitor which binds non-covalently to the active site of the enzyme through hydrogen bonds and hydrophobic interactions. Though, it’s IC50 (180 nM) is much higher than tazobactam, it has good affinity for CTX-M-15 (K i = 0.388 µM). This study concludes that ZINC03787097 compound can be used as seed molecule to design more efficient

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.

Human Salivary Protein Histatin 5 Has Potent Bactericidal Activity against ESKAPE Pathogens

PubMed Central

Du, Han; Puri, Sumant; McCall, Andrew; Norris, Hannah L.; Russo, Thomas; Edgerton, Mira

2017-01-01

ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumanni, Pseudomonas aeruginosa, and Enterobacter species) pathogens have characteristic multiple-drug resistance and cause an increasing number of nosocomial infections worldwide. Peptide-based therapeutics to treat ESKAPE infections might be an alternative to conventional antibiotics. Histatin 5 (Hst 5) is a salivary cationic histidine-rich peptide produced only in humans and higher primates. It has high antifungal activity against Candida albicans through an energy-dependent, non-lytic process; but its bactericidal effects are less known. We found Hst 5 has bactericidal activity against S. aureus (60–70% killing) and A. baumannii (85–90% killing) in 10 and 100 mM sodium phosphate buffer (NaPB), while killing of >99% of P. aeruginosa, 60–80% E. cloacae and 20–60% of E. faecium was found in 10 mM NaPB. Hst 5 killed 60% of biofilm cells of P. aeruginosa, but had reduced activity against biofilms of S. aureus and A. baumannii. Hst 5 killed 20% of K. pneumonia biofilm cells but not planktonic cells. Binding and uptake studies using FITC-labeled Hst 5 showed E. faecium and E. cloacae killing required Hst 5 internalization and was energy dependent, while bactericidal activity was rapid against P. aeruginosa and A. baumannii suggesting membrane disruption. Hst 5-mediated killing of S. aureus was both non-lytic and energy independent. Additionally, we found that spermidine conjugated Hst 5 (Hst5-Spd) had improved killing activity against E. faecium, E. cloacae, and A. baumannii. Hst 5 or its derivative has antibacterial activity against five out of six ESKAPE pathogens and may be an alternative treatment for these infections. PMID:28261570

Human Salivary Protein Histatin 5 Has Potent Bactericidal Activity against ESKAPE Pathogens.

PubMed

Du, Han; Puri, Sumant; McCall, Andrew; Norris, Hannah L; Russo, Thomas; Edgerton, Mira

2017-01-01

ESKAPE ( Enterococcus faecium , Staphylococcus aureus , Klebsiella pneumoniae , Acinetobacter baumanni , Pseudomonas aeruginosa , and Enterobacter species) pathogens have characteristic multiple-drug resistance and cause an increasing number of nosocomial infections worldwide. Peptide-based therapeutics to treat ESKAPE infections might be an alternative to conventional antibiotics. Histatin 5 (Hst 5) is a salivary cationic histidine-rich peptide produced only in humans and higher primates. It has high antifungal activity against Candida albicans through an energy-dependent, non-lytic process; but its bactericidal effects are less known. We found Hst 5 has bactericidal activity against S. aureus (60-70% killing) and A. baumannii (85-90% killing) in 10 and 100 mM sodium phosphate buffer (NaPB), while killing of >99% of P. aeruginosa , 60-80% E. cloacae and 20-60% of E. faecium was found in 10 mM NaPB. Hst 5 killed 60% of biofilm cells of P. aeruginosa , but had reduced activity against biofilms of S. aureus and A. baumannii . Hst 5 killed 20% of K. pneumonia biofilm cells but not planktonic cells. Binding and uptake studies using FITC-labeled Hst 5 showed E. faecium and E. cloacae killing required Hst 5 internalization and was energy dependent, while bactericidal activity was rapid against P. aeruginosa and A. baumannii suggesting membrane disruption. Hst 5-mediated killing of S. aureus was both non-lytic and energy independent. Additionally, we found that spermidine conjugated Hst 5 (Hst5-Spd) had improved killing activity against E. faecium, E. cloacae , and A. baumannii . Hst 5 or its derivative has antibacterial activity against five out of six ESKAPE pathogens and may be an alternative treatment for these infections.

Evaluation of high-resolution melting curve analysis of ligation-mediated real-time PCR, a rapid method for epidemiological typing of ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter Species) pathogens.

PubMed

Woksepp, Hanna; Ryberg, Anna; Billström, Hanna; Hällgren, Anita; Nilsson, Lennart E; Marklund, Britt-Inger; Olsson-Liljequist, Barbro; Schön, Thomas

2014-12-01

A single-tube method, ligation-mediated real-time PCR high-resolution melt analysis (LMqPCR HRMA), was modified for the rapid typing of Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp. (ESKAPE) pathogens. A 97% agreement (60/62 isolates) was achieved in comparison to pulsed-field gel electrophoresis (PFGE) results, which indicates that LMqPCR HRMA is a rapid and accurate screening tool for monitoring nosocomial outbreaks. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Whole genome sequence of Enterobacter ludwigii type strain EN-119T, isolated from clinical specimens.

PubMed

Li, Gengmi; Hu, Zonghai; Zeng, Ping; Zhu, Bing; Wu, Lijuan

2015-04-01

Enterobacter ludwigii strain EN-119(T) is the type strain of E. ludwigii, which belongs to the E. cloacae complex (Ecc). This strain was first reported and nominated in 2005 and later been found in many hospitals. In this paper, the whole genome sequencing of this strain was carried out. The total genome size of EN-119(T) is 4952,770 bp with 4578 coding sequences, 88 tRNAs and 10 rRNAs. The genome sequence of EN-119(T) is the first whole genome sequence of E. ludwigii, which will further our understanding of Ecc. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

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

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

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

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.

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

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.

Antibacterial effects of the essential oils of commonly consumed medicinal herbs using an in vitro model.

PubMed

Soković, Marina; Glamočlija, Jasmina; Marin, Petar D; Brkić, Dejan; van Griensven, Leo J L D

2010-10-27

The chemical composition and antibacterial activity of essential oils from 10 commonly consumed herbs: Citrus aurantium, C. limon, Lavandula angustifolia, Matricaria chamomilla, Mentha piperita, M. spicata, Ocimum basilicum, Origanum vulgare, Thymus vulgaris and Salvia officinalis have been determined. The antibacterial activity of these oils and their main components; i.e. camphor, carvacrol, 1,8-cineole, linalool, linalyl acetate, limonene, menthol, a-pinene, b-pinene, and thymol were assayed against the human pathogenic bacteria Bacillus subtilis, Enterobacter cloacae, Escherichia coli O157:H7, Micrococcus flavus, Proteus mirabilis, Pseudomonas aeruginosa, Salmonella enteritidis, S. epidermidis, S. typhimurium, and Staphylococcus aureus. The highest and broadest activity was shown by O. vulgare oil. Carvacrol had the highest antibacterial activity among the tested components.

Defining the molecular pathologies in cloaca malformation: similarities between mouse and human

PubMed Central

Runck, Laura A.; Method, Anna; Bischoff, Andrea; Levitt, Marc; Peña, Alberto; Collins, Margaret H.; Gupta, Anita; Shanmukhappa, Shiva; Wells, James M.; Guasch, Géraldine

2014-01-01

Anorectal malformations are congenital anomalies that form a spectrum of disorders, from the most benign type with excellent functional prognosis, to very complex, such as cloaca malformation in females in which the rectum, vagina and urethra fail to develop separately and instead drain via a single common channel into the perineum. The severity of this phenotype suggests that the defect occurs in the early stages of embryonic development of the organs derived from the cloaca. Owing to the inability to directly investigate human embryonic cloaca development, current research has relied on the use of mouse models of anorectal malformations. However, even studies of mouse embryos lack analysis of the earliest stages of cloaca patterning and morphogenesis. Here we compared human and mouse cloaca development and retrospectively identified that early mis-patterning of the embryonic cloaca might underlie the most severe forms of anorectal malformation in humans. In mouse, we identified that defective sonic hedgehog (Shh) signaling results in early dorsal-ventral epithelial abnormalities prior to the reported defects in septation. This is manifested by the absence of Sox2 and aberrant expression of keratins in the embryonic cloaca of Shh knockout mice. Shh knockout embryos additionally develop a hypervascular stroma, which is defective in BMP signaling. These epithelial and stromal defects persist later, creating an indeterminate epithelium with molecular alterations in the common channel. We then used these animals to perform a broad comparison with patients with mild-to-severe forms of anorectal malformations including cloaca malformation. We found striking parallels with the Shh mouse model, including nearly identical defective molecular identity of the epithelium and surrounding stroma. Our work strongly suggests that early embryonic cloacal epithelial differentiation defects might be the underlying cause of severe forms of anorectal malformations in humans. Moreover

Analysis of the spectrum and antibiotic resistance of uropathogens in outpatients at a tertiary hospital.

PubMed

Yang, Bo; Yang, Fujia; Wang, Shanmei; Wang, Qian; Liu, Zhirui; Feng, Wei; Sun, Fengjun; Xia, Peiyuan

2018-05-01

The objective of this study was to analyse the distribution and antimicrobial resistance of bacterial uropathogens isolated from outpatients at Henan Provincial People's Hospital. A total of 1419 samples from 823 newly diagnosed and 596 recurrent UTI outpatients culture positive. Escherichia coli was the most common uropathogen. Compared with the recurrent group, the newly diagnosed group had a higher isolation rate of E. coli and Enterobacter cloacae but a lower isolation rate of Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter spp. Except for P. aeruginosa, the resistance of Gram-negative bacteria to most antibiotics was less than 30%. All Enterococcus and Staphylococcus spp. were sensitive to linezolid, vancomycin and teicoplanin. Both Gram-negative and -positive bacteria exhibited high susceptibility to fosfomycin. Uropathogens isolated from recurrent outpatients had higher resistance rates than did those isolated from newly diagnosed outpatients. Our study indicated that fosfomycin might be an excellent treatment option for outpatients with UTIs.

Characterization of extended-spectrum β-lactamase (ESBL)-producing Klebsiella, Enterobacter, and Citrobacter obtained in environmental samples of a Tunisian hospital.

PubMed

Dziri, Raoudha; Klibi, Naouel; Alonso, Carla Andrea; Said, Leila Ben; Bellaaj, Ridha; Slama, Karim Ben; Boudabous, Abdellatif; Torres, Carmen

2016-10-01

The assessment of the hospital environment as a reservoir of ESBL-producing Enterobacteriaceae in Tunisian hospitals is scarcely analyzed, except for Escherichia coli. The aim of this study was to evaluate the presence of ESBL-producing non-E. coli Enterobacteriaceae (ESBL-EbNoEc) in 300 samples of abiotic surfaces and the hands of patients and staff of a Tunisian Hospital, and to characterize the ESBL genes of the recovered isolates. ESBL-EbNoEc were recovered in 28 of 300 (9.3%) analyzed samples and were identified as Klebsiella pneumoniae (n= 11), Enterobacter cloacae (n=11), Citrobacter freundii (n=4) and Klebsiella oxytoca (n=2). The bla genes identified by PCR and sequencing among the strains were as follows: 11 K.pneumoniae strains [blaCTX-M-15+ blaTEM-1+ blaSHV-11 (n=6); blaCTX-M-15+ blaTEM-1+ blaSHV-28 (n=3); blaCTX-M-15+ blaTEM-1+ blaSHV-1 (n=2)], 11 E. cloacae strains [blaCTX-M-15 (n=6); blaCTX-M-15+ blaTEM-1b (n=2); blaCTX-M-15+ blaTEM-1b+ blaOXA-1 (n=1);blaCTX-M-15+ blaOXA-1 (n=1);blaSHV-12 (n=1)], 4 C. freundii strains [blaCTX-M-15] and 2 K. oxytoca strains [blaCTX-M-15 (n=1); blaSHV-12 (n=1)]. The ISEcp1 and orf477 sequences were identified upstream and downstream of the blaCTX-M-15 gene, respectively, in 3 K. pneumoniae and 3 E. cloacae isolates. The PFGE analysis demonstrated three unrelated pulsotypes in K. pneumoniae strains and five pulsotypes in E. cloacae. The uncontrolled dissemination of ESBL-producing bacteria, even in the hospital environment, has become a real problem and new strategies and hygienic rules are needed to stop this bacterial dissemination. Copyright © 2016 Elsevier Inc. All rights reserved.

Improvement of Gram-negative Susceptibility to Fluoroquinolones After Implementation of a Pre-Authorization Policy for Fluoroquinolone Use: A Decade-Long Experience

PubMed Central

Lee, Rachael A; Scully, Morgan; Kunz, Danielle F; Jones, T Aaron; Camins, Bernard; McCarty, Todd P; Moser, Stephen; Hoesley, Craig J; Pappas, Peter G

2017-01-01

Abstract Background Antibiotic use is a well-known risk factor for acquisition of drug-resistant bacteria and community antibiotic prescribing can drive high rates of resistance within the hospital setting. Owing to concerns over increasing fluoroquinolone (FQ) resistance among Gram-negative organisms at UAB Hospital, our stewardship program implemented a pre-authorization policy. The goal of this study was to assess the relationship between hospital fluoroquinolone use and antibiotic resistance. Methods In 2006, the inpatient formulary was consolidated to only ciprofloxacin and moxifloxacin with implementation of guidelines for use to limit inpatient prescribing. Any use outside of these guidelines required approval from an infectious diseases physician. Organism-specific data were obtained from the clinical microbiology database and FQ use was obtained from the hospital database. Correlations were calculated using Pearson’s coefficient. Results From 1998 to 2004, FQ use peaked at 173 days of therapy (DOT)/1,000 patient-days, but has remained below 60 DOT/1,000 patient-days since restriction implementation (Figure 1). FQ susceptibility was documented for five common Gram-negative isolates, P. aeruginosa, Acinetobacter spp., Enterobacter cloacae, E. coli, and K. pneumoniae, over an 18-year period (1998–2016). Common hospital acquired pathogens, including Pseudomonas aeruginosa, Acinetobacter spp. and Enterobacter cloacae improved in their susceptibilities to fluoroquinolones. Acinetobacter went from 35% to over 50% susceptible in the preceding 10 years after the policy. Pseudomonas improved from 50% susceptible to over 70% and Enterobacter improved from less than 50% to over 90% susceptible. Interestingly this improvement was not seen for E. coli which continued to show a decline in susceptibility from over 90% to near 60% in 2016. Conclusion In a large academic hospital setting, FQ susceptibility for common hospital-acquired GNRS improved significantly

Antibiotics involved in the occurrence of antibiotic-resistant bacteria: a nationwide multilevel study suggests differences within antibiotic classes.

PubMed

Gbaguidi-Haore, Houssein; Dumartin, Catherine; L'Hériteau, François; Péfau, Muriel; Hocquet, Didier; Rogues, Anne-Marie; Bertrand, Xavier

2013-02-01

To identify the antibiotics potentially the most involved in the occurrence of antibiotic-resistant bacteria from an ecological perspective in French healthcare facilities (HCFs). This study was based on data from the French antimicrobial surveillance network (ATB-RAISIN, 2007-09). Antibiotics were expressed in defined daily doses per 1000 patient-days. Antibiotic-resistant bacteria were considered as count data adjusted for patient-days. These were third-generation cephalosporin (3GC)- and ciprofloxacin-resistant Escherichia coli, cefotaxime-resistant Enterobacter cloacae, methicillin-resistant Staphylococcus aureus and ceftazidime-, imipenem- and ciprofloxacin-resistant Pseudomonas aeruginosa. Three-level negative binomial regression models were built to take into account the hierarchical structure of data: level 1, repeated measures each year (count outcome, time, antibiotics); level 2, HCFs (type and size); and level 3, regions (geographical area). A total of 701 HCFs from 20 French regions and up to 1339 HCF-years were analysed. The use of ceftriaxone, but not of cefotaxime, was positively correlated with incidence rates of 3GC- and ciprofloxacin-resistant E. coli. In contrast, both 3GCs were positively correlated with the incidence rate of cefotaxime-resistant E. cloacae. Higher levels of use of ciprofloxacin and/or ofloxacin, but not of levofloxacin, were associated with higher incidence rates of 3GC- and ciprofloxacin-resistant E. coli, cefotaxime-resistant E. cloacae, methicillin-resistant S. aureus and ceftazidime- and ciprofloxacin-resistant P. aeruginosa. Our study suggests differences within antibiotic classes in promoting antibiotic resistance. We identified ceftriaxone, ciprofloxacin and ofloxacin as priority targets in public health strategies designed to reduce antibiotic use and antibiotic-resistant bacteria in French HCFs.

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.

Novel depsides as potential anti-inflammatory agents with potent inhibitory activity against Escherichia coli-induced interleukin-8 production.

PubMed

Lv, Peng-Cheng; Xiong, Jing; Chen, Jin; Wang, Kai-Rui; Mao, Wen-Jun; Zhu, Hai-Liang

2010-08-01

Sixteen novel depsides were synthesized for the first time. Their chemical structures were clearly determined by (1)H NMR, ESI mass spectra, and elemental analyses. All the compounds were assayed for antibacterial activities against three Gram-positive bacterial strains (Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 6538, and Streptococcus faecalis ATCC 9790) and three Gram-negative bacterial strains (Escherichia coli ATCC 35218, Pseudomonas aeruginosa ATCC 13525, and Enterobacter cloacae ATCC 13047) by the MTT method. Compound 2-(2-methoxy-2-oxoethyl)phenyl 5-bromonicotinate (5) exhibited significant antibacterial activities against E. coli ATCC 35218 with an MIC of 0.78 microg/mL, which was superior to the positive control kanamycin B. In addition, compound 5 showed potent inhibitory activity against E. coli-induced interleukin-8 production.

Phage-mediated Shiga toxin (Stx) horizontal gene transfer and expression in non-Shiga toxigenic Enterobacter and Escherichia coli strains.

PubMed

Khalil, Rowaida K S; Skinner, Craig; Patfield, Stephanie; He, Xiaohua

2016-07-01

Enterobacter cloacae M12X01451 strain recently identified from a clinical specimen produces a new Stx1 subtype (Stx1e) that was not neutralized by existing anti-Stx1 monoclonal antibodies. Acquisition of stx by Ent. cloacae is rare and origin/stability of stx1e in M12X01451 is not known. In this study, we confirmed the ability of Stx1a- and Stx1e-converting phages from an Escherichia coli O157:H7 strain RM8530 and M12X01451 respectively to infect several E. coli and Ent. cloacae strains. stx1e was detected in 97.5% and 72.5% of progenies of strains lysogenized by stx1e phage after 10 (T10) and 20 (T20) subcultures, versus 65% and 17.5% for stx1a gene. Infection of M12X01451 and RM8530 with each other's phages generated double lysogens containing both phages. stx1a was lost after T10, whereas the stx1e was maintained even after T20 in M12X01451 lysogens. In RM8530 lysogens, the acquired stx1e was retained with no mutations, but 20% of stx1a was lost after T20 ELISA and western blot analyses demonstrated that Stx1e was produced in all strains lysogenized by stx1e phage; however, Stx1a was not detected in any lysogenized strain. The study results highlight the potential risks of emerging Stx-producing strains via bacteriophages either in the human gastrointestinal tract or in food production environments, which are matters of great concern and may have serious impacts on human health. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Single molecule sequencing to track plasmid diversity of hospital-associated carbapenemase-producing Enterobacteriaceae

PubMed Central

Conlan, Sean; Thomas, Pamela J.; Deming, Clayton; Park, Morgan; Lau, Anna F.; Dekker, John P.; Snitkin, Evan S.; Clark, Tyson A.; Luong, Khai; Song, Yi; Tsai, Yu-Chih; Boitano, Matthew; Gupta, Jyoti; Brooks, Shelise Y.; Schmidt, Brian; Young, Alice C.; Thomas, James W.; Bouffard, Gerard G.; Blakesley, Robert W.; Mullikin, James C.; Korlach, Jonas; Henderson, David K.; Frank, Karen M.; Palmore, Tara N.; Segre, Julia A.

2014-01-01

Public health officials have raised concerns that plasmid transfer between Enterobacteriaceae species may spread resistance to carbapenems, an antibiotic class of last resort, thereby rendering common healthcare-associated infections nearly impossible to treat. We performed comprehensive surveillance and genomic sequencing to identify carbapenem-resistant Enterobacteriaceae in the NIH Clinical Center patient population and hospital environment in order to to articulate the diversity of carbapenemase-encoding plasmids and survey the mobility of and assess the mobility of these plasmids between bacterial species. We isolated a repertoire of carbapenemase-encoding Enterobacteriaceae, including multiple strains of Klebsiella pneumoniae, Klebsiella oxytoca, Escherichia coli, Enterobacter cloacae, Citrobacter freundii, and Pantoea species. Long-read genome sequencing with full end-to-end assembly revealed that these organisms carry the carbapenem-resistance genes on a wide array of plasmids. Klebsiella pneumoniae and Enterobacter cloacae isolated simultaneously from a single patient harbored two different carbapenemase-encoding plasmids, overriding the epidemiological scenario of plasmid transfer between organisms within this patient. We did, however, find evidence supporting horizontal transfer of carbapenemase-encoding plasmids between Klebsiella pneumoniae, Enterobacter cloacae and Citrobacter freundii in the hospital environment. Our comprehensive sequence data, with full plasmid identification, challenges assumptions about horizontal gene transfer events within patients and identified wider possible connections between patients and the hospital environment. In addition, we identified a new carbapenemase-encoding plasmid of potentially high clinical impact carried by Klebsiella pneumoniae, Escherichia coli, Enterobacter cloacae and Pantoea species, from unrelated patients and the hospital environment. PMID:25232178

Chemical Kinetic and Molecular Genetic Study of Selenium Oxyanion Reduction by Enterobactor cloacae SLD1a-1

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

Ma,J.; Kobayashi, D.; Yee, N.

2007-01-01

Microbial processes play an important role in the redox transformations of toxic selenium oxyanions. In this study, we employed chemical kinetic and molecular genetic techniques to investigate the mechanisms of Se(IV) and Se(VI) reduction by the facultative anaerobe Enterobacter cloacae SLD1a-1. The rates of microbial selenium oxyanion reduction were measured as a function of initial selenium oxyanion concentration (0-1.0 mM) and temperature (10-40 C), and mutagenesis studies were performed to identify the genes involved in the selenium oxyanion reduction pathway. The results indicate that Se(IV) reduction is significantly more rapid than the reduction of Se(VI). The kinetics of the reductionmore » reactions were successfully quantified using the Michaelis-Menten kinetic equation. Both the rates of Se(VI) and Se(IV) reduction displayed strong temperature-dependence with Ea values of 121 and 71.2 kJ/mol, respectively. X-ray absorption near-edge spectra collected for the precipitates formed by Se(VI) and Se(IV) reduction confirmed the formation of Se(0). A miniTn5 transposon mutant of E. cloacae SLD1a-1 was isolated that had lost the ability to reduce Se(VI) but was not affected in Se(IV) reduction activity. Nucleotide sequence analysis revealed the transposon was inserted within a tatC gene, which encodes for a central protein in the twin arginine translocation system. Complementation by the wild-type tatC sequence restored the ability of mutant strains to reduce Se(VI). The results suggest that Se(VI) reduction activity is dependent on enzyme export across the cytoplasmic membrane and that reduction of Se(VI) and Se(IV) are catalyzed by different enzymatic systems.« 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.

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.

Preparation of melt-spun antimicrobially modified LDH/polyolefin nanocomposite fibers.

PubMed

Kutlu, Burak; Schröttner, Percy; Leuteritz, Andreas; Boldt, Regine; Jacobs, Enno; Heinrich, Gert

2014-08-01

Layered double hydroxide (LDH) was synthesized and organically modified with camphorsulfonic acid (CSA) and ciprofloxacin. The thermal stability of CSA was improved remarkably under LDH shielding. A minimal inhibitory concentration of free CSA against tested bacteria was determined in order to define the essential quantity in LDH modification. The modified LDHs were melt-compounded with high density polyethylene and the prepared nanocomposites were further melt-spun using a piston-type spinning device. The melt-spun fibers were tested for their antimicrobial activity against Escherichia coli, Proteus vulgaris, Pseudomonas aeruginosa, Enterobacter cloacae, Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus pyogenes. CSA integrated fibers show susceptibility against Gram-positive bacteria and ciprofloxacin integrated fibers showed activity against both Gram-positive and Gram-negative bacteria. Copyright © 2014 Elsevier B.V. All rights reserved.

The Disinfecting Potential of Contact Lens Soutions used by Sultan Qaboos University Students

PubMed Central

Nzeako, B. C.; Al-Sumri, Sara H.

2011-01-01

Objectives: This study aimed to determine the disinfecting potential of some contact lens solutions used by some university students in Oman. Methods: This work was carried out from January to June 2010 in the Department of Microbiology & Immunology, College of Medicine and Health Sciences, Sultan Qaboos University, Oman. Fifty disinfecting solutions, in which contact lenses were disinfected according to the manufacturers’ instructions, were collected from the students and plated on various microbiological culture media. Bacterial isolates were identified by API-20E, API-20NE and Phoenix automated systems while fungi were identified by their cultural characteristics and biochemistry. Results: From 98 isolates, Pseudomonas aeruginosa was 23.5%; Penicillium, 13%; Candida species, 9.2%; coagulase negative staphylococci, 9.2%; Serratia marcescens, 6.1%; Bacillus, 5.1%; Aspergillus flavus, 5.1%; Serratia liquefaciens, Pseudomonas fluorescens, Enterobacter cloacae and Aspergillus niger, 4.1% each; Chryseomonas luteola and Chryseomonas indologenes, 3.1% each; Stenotrophomonas maltophilia, Serratia odorifera, 2.0% each; Enterobacter aerogenes and Klebsiella pneumoniae, 1% each. Most isolates (65%) came from polyhexanide containing solutions. Conclusion: Contact lens disinfecting solutions with the same formulations, but manufactured by different companies, possessed different disinfecting potentials. PMID:21969898

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

Influence of culture site-specific MIC distributions on the pharmacokinetic and pharmacodynamic properties of piperacillin/tazobactam and piperacillin: a data analysis.

PubMed

Frei, Christopher R; Hampton, Shanna L; Burgess, David S

2006-07-01

Investigators who perform pharmacokinetic/pharmacodynamic (PK-PD) modeling with Monte Carlo simulation have historically not stratified microbiological data by culture site. This lack of stratification might be problematic if susceptibility patterns differ among sites and might lead to differences in PK-PD. This study compared the PK-PD of 2 antimicrobial regimens against 5 gram-negative bacterial species form 3 culture sites. This data analysis was performed at the Department of Pharmacology, The University of Texas Health Science Center, San Antonio, Texas. Blood, pulmonary (ie, bronchial, endotracheal, lung, respiratory, sputum, and tracheal secretions), and wound distributions of MICs were extracted from the 2002 Intensive Care Unit Surveillance System database. Bacteria included Acinetobacter baumannii, Enterobacter cloacae, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The PK properties of piperacillin/tazobactam (3.375 g every 4 hours) and piperacillin (3 g every 4 hours) were obtained from studies in healthy volunteers. Monte Carlo simulation was used in 10,000 patients for each antimicrobial-bacteria-culture site combination. The cumulative fraction of response (CFR) for a free percentage time above the MIC of > or =50% was determined for each combination, and a clinically significant difference was defined a priori as > or =10%. Data from 2408 pulmonary, 490 blood, and 242 wound isolates were included. For piperacillin/tazobactam, the CFR varied <10% by culture site in all 5 bacterial species. Site-specific differences were noted in MIC50 for piperacillin versus E cloacae and E coli and MIC90 for piperacillin/tazobactam versus K pneumoniae and P aeruginosa. Likewise, for piperacillin, the CFR was similar among the 3 culture sites for P aeruginosa. However, the CFR for piperacillin varied by > or =10% for A baumannii (blood > wound), E cloacae (pulmonary > blood), E coli (pulmonary and blood > wound), and K pneumoniae (wound > blood

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

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

Long-Term, Low-Frequency Cluster of a German-Imipenemase-1-Producing Enterobacter hormaechei ssp. steigerwaltii ST89 in a Tertiary Care Hospital in Germany.

PubMed

Wendel, Andreas F; Meyer, Sebastian; Deenen, René; Köhrer, Karl; Kolbe-Busch, Susanne; Pfeffer, Klaus; Willmann, Matthias; Kaasch, Achim J; MacKenzie, Colin R

2018-05-11

Enterobacter cloacae complex is a common cause of hospital outbreaks. A retrospective and prospective molecular analysis of carbapenem-resistant clinical isolates in a tertiary care center demonstrated an outbreak of a German-imipenemase-1 (GIM-1) metallo-beta-lactamase-producing Enterobacter hormaechei ssp. steigerwaltii affecting 23 patients between 2009 and 2016. Thirty-three isolates were sequence type 89 by conventional multilocus sequence typing (MLST) and displayed a maximum difference of 49 out of 3,643 targets in the ad-hoc core-genome MLST (cgMLST) scheme (SeqSphere+ software; Ridom, Münster, Germany). The relatedness of all isolates was confirmed by further maximum-likelihood phylogeny. One clonal complex of highly related isolates (≤15 allele difference in cgMLST) contained 17 patients, but epidemiological data only suggested five transmission events. The bla GIM-1 -gene was embedded in a class-1-integron (In770) and the Tn21-subgroup transposon Tn6216 (KC511628) on a 25-kb plasmid. Environmental screening detected one colonized sink trap in a service room. The outbreak was self-limited as no further bla GIM-1 -positive E. hormaechei has been isolated since 2016. Routine molecular screening of carbapenem-nonsusceptible gram-negative isolates detected a long-term, low-frequency outbreak of a GIM-1-producing E. hormaechei ssp. steigerwaltii clone. This highlights the necessity of molecular surveillance.

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

Single-stage operation without temporary colostomy for persistent cloaca with a short common channel.

PubMed

Masuko, T; Higashimoto, Y; Iwai, J

2005-11-01

Colorectal decompression with a catheter was performed for evacuation of stool before definitive surgery in two patients with a persistent cloaca. Two newborn female infants with persistent cloaca received placement of a silicone balloon-tipped catheter in the rectum via the cloacal orifice under fluoroscopic guidance at the time of diagnosis. The length of the cloaca was 2 and 1.5 cm, respectively. The diameter of the catheter was matched to the patients' rectal size and the open end was wrapped in a diaper to allow continuous drainage of stool. The infants underwent bowel irrigation with warm saline thrice a day, at home. Total urogenital mobilization was carried out in the infants at the age of 7 and 8 months, respectively. Both infants had no abdominal distension, colorectal dilatation, or urinary tract infection while the catheter was in situ. The postoperative course was uneventful, except for minimal wound dehiscence in one patient. At present, both infants can void spontaneously without any urological problems. In infants with a persistent cloaca less than 3 cm long and normal urinary tract function, adequate evacuation of stool may be achieved by colorectal decompression with a catheter, thus avoiding the need for a colostomy.

Subpubic sinus: a remnant of cloaca.

PubMed

Chou, T D; Chu, C C; Diau, G Y; Chiang, J H

1995-05-01

A 14-month-old girl had purulent discharge from a sinus over the subpubic region for 2 weeks. Radiography and voiding cystourethrography revealed a 4.5 cm. long fistula extending to the retropubic region without any connection to the lower urinary tract. The fistula was excised. Histological findings revealed that the fistula had 3 different types of epithelium: stratified squamous, transitional and columnar. Clinical and pathological findings indicated that the sinus was most likely a remnant of the cloaca.

[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

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.

[Clinical observation of the effects of FE combined enzymes on the infection of the granulation burn wound during late post burns stage].

PubMed

Zheng, Ji; Liu, Xu-sheng; Huang, Yue-sheng; Liu, Chun-yu

2006-02-01

To observe the effects of combined FE enzymes on the infection of the granulation burn wound during late postburn stage in controlling burn wound infection caused by common antibiotic resistant bacteria. Thirty patients in our burn ward were enrolled and were randomly divided into A [treated with combined FE enzymes (50 ml dissolved in 0-150 ml normal saline to reach the final concentration of 1-3 U/ml)] and B (treated with gentamicin) groups, with 15 patients in each group. Several layers of gauze, either soaked with combined FE enzyme in A or gentamicin in B group, were used to cover the burn wounds once to twice a day. Bacterial culture from the burn wound exudation before and after drug administration was done before the application of the agents. The bacteria in the burn wounds and their susceptibility to antibiotics were identified. The healing time of the burn wounds was recorded. Furthermore, the healing rate of the burn wound was recorded on the 3rd, 5th, 8th, 10th and 12th post skin grafting days (PSGD). The dominating bacteria in the burn wounds in both groups were Pseudomonas aeruginosa, Escherichia coli, Enterobacter cloacae and MRSA. The susceptibility rate of bacteria ( MRSA, Staphylococcus epidermidis, Staphylococcus saprophyte, Pseudomonas aeruginosa, Escherichia coli and Enterobacter cloacae) to combined FE enzyme was 93.8%, 100.0%, 100.0%, 100.0%, 100.0% and 95.0% respectively, which were much higher than those in B group (17.6%, 31.3%, 28.6%, 44.0%, 33.3%, 28.0% respectively, P < 0.1. The wound healing time after skin grafting in A group (10.6 +/- 1.5 days) was significantly shorter than that in B group (15.3 +/- 1.7 days, P < 0.01). The wound healing rate on 10 PSGD in A group was (85.4 +/- 2.4)%, and which was only (51.3 +/- 1.5% in B group (P < 0.01) Combined FE enzyme can effectively control burn wound infection, so that the interval between skin grafting and wound healing can be shortened and success rate of skin grafting be improved.

Inhibition of Fosfomycin Resistance Protein FosA by Phosphonoformate (Foscarnet) in Multidrug-Resistant Gram-Negative Pathogens

PubMed Central

Ito, Ryota; Tomich, Adam D.; McElheny, Christi L.; Mettus, Roberta T.; Sluis-Cremer, Nicolas

2017-01-01

ABSTRACT FosA proteins confer fosfomycin resistance to Gram-negative pathogens via glutathione-mediated modification of the antibiotic. In this study, we assessed whether inhibition of FosA by sodium phosphonoformate (PPF) (foscarnet), a clinically approved antiviral agent, would reverse fosfomycin resistance in representative Gram-negative pathogens. The inhibitory activity of PPF against purified recombinant FosA from Escherichia coli (FosA3), Klebsiella pneumoniae (FosAKP), Enterobacter cloacae (FosAEC), and Pseudomonas aeruginosa (FosAPA) was determined by steady-state kinetic measurements. The antibacterial activity of PPF against FosA in clinical strains of these species was evaluated by susceptibility testing and time-kill assays. PPF increased the Michaelis constant (Km) for fosfomycin in a dose-dependent manner, without affecting the maximum rate (Vmax) of the reaction, for all four FosA enzymes tested, indicating a competitive mechanism of inhibition. Inhibitory constant (Ki) values were 22.6, 35.8, 24.4, and 56.3 μM for FosAKP, FosAEC, FosAPA, and FosA3, respectively. Addition of clinically achievable concentrations of PPF (∼667 μM) reduced the fosfomycin MICs by ≥4-fold among 52% of the K. pneumoniae, E. cloacae, and P. aeruginosa clinical strains tested and led to a bacteriostatic or bactericidal effect in time-kill assays among representative strains. PPF inhibits FosA activity across Gram-negative species and can potentiate fosfomycin activity against the majority of strains with chromosomally encoded fosA. These data suggest that PPF may be repurposed as an adjuvant for fosfomycin to treat infections caused by some FosA-producing, multidrug-resistant, Gram-negative pathogens. PMID:28993329

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.

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

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

Bio-reduction of Cr(VI) by exopolysaccharides (EPS) from indigenous bacterial species of Sukinda chromite mine, India.

PubMed

Harish, R; Samuel, Jastin; Mishra, R; Chandrasekaran, N; Mukherjee, A

2012-07-01

Chrome mining activity has contributed intensively towards pollution of hexavalent chromium around Sukinda Valley, Orissa, India. In an attempt to study the specific contribution of exopolysaccharides (EPS) extracted from indigenous isolates towards Cr(VI) reduction, three chromium (VI) tolerant strains were isolated from the effluent mining sludge. Based on the tolerance towards Cr(VI) and EPS production capacity, one of them was selected for further work. The taxonomic identity of the selected strain was confirmed to be Enterobacter cloacae (showing 98% similarity in BLAST search to E. cloacae) through 16S rRNA analysis. The EPS production was observed to increase with increasing Cr(VI) concentration in the growth medium, highest being 0.078 at 100 mg/l Cr(VI). The extracted EPS from Enterobacter cloacae SUKCr1D was able to reduce 31.7% of Cr(VI) at 10 mg/l concentration, which was relevant to the prevailing natural concentrations at Sukinda mine effluent sludge. The FT-IR spectral studies confirmed the surface chemical interactions of hexavalent chromium with EPS.

Integration of Pseudomonas aeruginosa and Legionella pneumophila in drinking water biofilms grown on domestic plumbing materials.

PubMed

Moritz, Miriam M; Flemming, Hans-Curt; Wingender, Jost

2010-06-01

Drinking water biofilms were grown on coupons of plumbing materials, including ethylene-propylene-diene-monomer (EPDM) rubber, silane cross-linked polyethylene (PE-X b), electron-ray cross-linked PE (PE-X c) and copper under constant flow-through of cold tap water. After 14 days, the biofilms were spiked with Pseudomonas aeruginosa, Legionella pneumophila and Enterobacter nimipressuralis (10(6) cells/mL each). The test bacteria were environmental isolates from contamination events in drinking water systems. After static incubation for 24 h, water flow was resumed and continued for 4 weeks. Total cell count and heterotrophic plate count (HPC) of biofilms were monitored, and P. aeruginosa, L. pneumophila and E. nimipressuralis were quantified, using standard culture-based methods or culture-independent fluorescence in situ hybridization (FISH). After 14 days total cell counts and HPC values were highest on EPDM followed by the plastic materials and copper. P. aeruginosa and L. pneumophila became incorporated into drinking water biofilms and were capable to persist in biofilms on EPDM and PE-X materials for several weeks, while copper biofilms were colonized only by L. pneumophila in low culturable numbers. E. nimipressuralis was not detected in any of the biofilms. Application of the FISH method often yielded orders of magnitude higher levels of P. aeruginosa and L. pneumophila than culture methods. These observations indicate that drinking water biofilms grown under cold water conditions on domestic plumbing materials, especially EPDM and PE-X in the present study, can be a reservoir for P. aeruginosa and L. pneumophila that persist in these habitats mostly in a viable but non-culturable state.

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%.

Synergistic antibacterial activity of Salvia officinalis and Cichorium intybus extracts and antibiotics.

PubMed

Stefanović, Olgica D; Stanojević, Dragana D; Comić, Ljiljana R

2012-01-01

Synergistic activity of Salvia officinalis and Cichorium intybus extracts and commonly used antibiotics, amoxicillin and chloramphenicol, were evaluated. Interactions between plant extracts and antibiotics were tested by checkerboard method and interpreted as FIC index. Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853 and clinical isolates Staphylococcus aureus, Bacillus subtilis, Enterobacter cloacae, Klebsiella pneumoniae, Escherichia coli and Proteus mirabilis were used. Salvia officinalis showed better synergistic capacity than Cichorium intybus. Synergistic interactions were observed between amoxicillin and acetone or ethyl acetate extract of Salvia officinalis and between chloramphenicol and ethyl acetate extract of Salvia officinalis. In the presence of sub-inhibitory concentration (1/4 MIC to 1/32 MIC) of sage extracts, the MIC values of antibiotics were decreased by 2- to 10-fold. Synergism was observed against all test bacteria, except Escherichia coli. The combinations of acetone and ethyl acetate extract from Cichorium intybus and antibiotics resulted in additive and indifferent effects against tested bacteria.

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.

[Antibacterial activity of sulopenem, a new parenteral penem antibiotic].

PubMed

Inoue, E; Komoto, E; Taniyama, Y; Mitsuhashi, S

1996-04-01

Sulopenem, a new penem antibiotic, was compared with other antibiotics with regard to in vitro antibacterial and bactericidal activities, stabilization against beta-lactamases, and effect on the release of lipopolysaccharide from Gram-negative bacteria. The results are summarized as follows. 1. Sulopenem showed more potent activities than other antibiotics against both Gram-positive and Gram-negative bacteria except Pseudomonas aeruginosa. 2. Sulopenem showed potent bactericidal activities (MIC/MBC) against both Gram-positive and Gram-negative bacteria. Time kill studies against Staphylococcus aureus, Escherichia coli, Enterobacter cloacae and Citrobacter freundii showed potent bactericidal activities of sulopenem. 3. Sulopenem was found to possess a stronger activity than other antibiotics against beta-lactamase-producing strains except P. aeruginosa and Stenotrophomonas maltophilia. 4. In particular, sulopenem was found to be more stable to the hydrolysis by various beta-lactamases produced by Gram-negative bacteria than any other antibiotics tested. Vmax/Km values of sulopenem were smaller than those of cefotiam for all tested beta-lactamases, which reflected a broad antibacterial spectrum of sulopenem. 5. E. coli ML4707 exposed to sulopenem and imipenem released less endotoxin than did controls at all concentration ranges tested. In contrast, the strain exposed to ceftazidime at bacteriostatic concentrations released a large amount of endotoxin.

[Antimicrobial susceptibility of uropathogens from uncomplicated urinary tract infection in a pediatric hospital].

PubMed

López-Martínez, Briceida; Calderón-Jaimes, Ernesto; Olivar-López, Víctor; Parra-Ortega, Israel; Alcázar-López, Virginia; Castellanos-Cruz, María Del Carmen; de la Garza-López, Alicia

Urinary tract infection in children is well recognized as a cause of acute morbidity and chronic medical conditions. As a result, appropriate use of antimicrobial agents, however, increases antibiotic resistance and complicates its treatment due to increased patient morbidity, costs, rates of hospitalization, and use of broader-spectrum antibiotics. The goal of this study was to determine antibiotic susceptibility to commonly used agents for urinary tract infection against recent urinary isolates. A total of 457 consecutive children attending the emergency room at the Hospital Infantil de México Federico Gómez with symptoms of uncomplicated lower urinary tract infection were eligible for inclusion. Patients who had had symptoms for≥7 days and those who had had previous episodes of urinary tract infection, received antibiotics or other complicated factors were excluded. Midstream and catheter urine specimens were collected. All isolates were identified and the in vitro activities of antimicrobials were determined. The most frequently isolated urinary pathogens were as follows: Escherichia coli (E. coli) (312, 68.3%), Enterococcus spp. (42, 11%), Klebsiella pneumoniae (K. pneumoniae) (40, 8.7%), Pseudomonas aeruginosa (P. aeruginosa) (34, 7.5%), Proteus mirabilis (P. mirabilis) (21, 4.5%), Enterobacter cloacae (8, 1.7%). The resistance to trimetoprim/sulfametoxazol (%) was 73.7, 62.2, 100, 52, and 50, respectively, for E. coli, K. pneumoniae, P. aeruginosa, P. mirabilis and Enterobacter spp., 92.5 for Enterococcus faecalis (E. faecalis) and 49.9 for Enterococcus faecium (E. faecium). Ampicillin was 86.3, 45, 100, 47.9, and 66.6% for the same strains, ciprofloxacin 33.8, 9, 18.8, 0, 0%, nitrofurantoin 4.4, 13, 97.7, 70, 0%; to E. faecalis 0% and 16.7% to E. faecium. Frequently prescribed empirical agents for uncomplicated urinary tract infection demonstrate lowered in vitro susceptibilities when tested against recent clinical isolates. Copyright © 2014 Hospital

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

Head-cloaca controlled current stunning: assessment of brain and heart activity and meat quality.

PubMed

Lambooij, E; Reimert, H G M; Workel, L D; Hindle, V A

2012-01-01

1. Behavioural and neural responses of 65 broilers to head-to-cloaca electrical stunning were evaluated and meat quality was assessed on two groups of 25 broilers stunned either head to cloaca, or in a conventional water bath method. 2. On the EEG recordings, a general epileptiform insult was observed when applying a current of 100 mA (100 Hz) or 70 mA (70 Hz) for 1·5 s. This general epileptiform insult shows a tonic, clonic and exhaustion phase followed by spikes of alpha, beta, theta and delta waves with duration of on average 34 ± 12 s and 39 ± 23 s respectively. These birds may have been unconscious for 20 s or longer, according to the correlation dimension analyses. 3. The heart rate decreased significantly (P < 0·05) after stunning and recovered after 60 s. 4. Within a confidence limit of 95%, taking into account the number of animals with a reliable EEG, the chance of an effective stun of all broilers lies between 0·9 and 1·0 with a current of 70 mA (100 Hz for 1·5 s; n = 28) and with 100 mA (100 Hz for 1·5 s; n = 27). 5. The shear force of breast fillets was slightly lower (P < 0·01) 4 d post mortem compared with the conventional water bath stunned group (set at 100 mA, 100 Hz for 10 s). The percentage of fillets and legs without blood splashes was higher, and the percentage with severe blood splashes lower-to-none, for carcases stunned head-cloaca. 6. It can be concluded that broilers are effectively stunned with the head-cloaca method by using a controlled current of 70 mA or 100 mA for 1·5 s. The fillets and legs of bird stunned head-cloaca showed fewer blood splashes in the muscles compared with birds stunned in a conventional water bath.

Genetic Identification of an Enzymatic Se(VI) Reduction Pathway

NASA Astrophysics Data System (ADS)

Yee, N.; Kobayashi, D. Y.

2006-12-01

Enterobacter cloacae is a biofilm-forming organism that colonizes the subterranean portions of plants. Because of its ability to catalyze the reduction of selenium oxyanions, this bacterium plays an important role in Se(0) biomineralization and Se cycling in soils. Identification of the genes that regulate selenate reductase activity is needed to elucidate the mechanisms employed by this organism to reduce Se(VI). However, the genes in E. cloacae involved in selenium reduction are currently unknown. In this study, transposon mutagenesis and direct cloning techniques were used to identify genetic regions in E. cloacae SLD1a-1 associated with selenate reductase activity. The mini-Tn5 transposon system was used to produce mutants that have lost the ability to reduce selenate. E. cloacae mutants and genomic library clones heterologously expressed in E. coli S17-1 were screened for activity on LB agar supplemented with sodium selenate. The rate of selenate reduction by the clones was measured in liquid minimal media, and the Se(0) minerals formed by the clones were examined using EXAFS, TEM, and XRD. The transposon mutagenesis experiments revealed that mutation of menaquinone biosynthesis genes inhibits selenate reduction. The direct cloning experiments showed that heterologous expression of the global anaerobic regulatory gene fnr from Enterobacter cloacae in the non Se-reducing strain E. coli S17-1 activated selenate reductase activity and the ability to precipitate Se(0) particles. Se(VI) reduction by E. coli S17-1 containing the fnr gene occurred at similar rates as E. cloacae and produced elemental selenium particles with identical morphologies and short range atomic order. These findings indicate that Se(VI) reduction by facultative anaerobes is regulated by anaerobic electron carriers and oxygen sensing transcription factors.

Physiological responses of Microcystis aeruginosa against the algicidal bacterium Pseudomonas aeruginosa.

PubMed

Zhou, Su; Yin, Hua; Tang, Shaoyu; Peng, Hui; Yin, Donggao; Yang, Yixuan; Liu, Zehua; Dang, Zhi

2016-05-01

Proliferation of cyanobacteria in aquatic ecosystems has caused water security problems throughout the world. Our preliminary study has showed that Pseudomonas aeruginosa can inhibit the growth of cyanobacterium, Microcystis aeruginosa. In order to explore the inhibitory mechanism of P. aeruginosa on the cell growth and synthesis of intracellular substances of M. aeruginosa, concentrations of Chlorophyll-a, intracellular protein, carbohydrate, enzyme activities and ion metabolism of M. aeruginosa, were investigated. The results indicated that 83.84% algicidal efficiency of P. aeruginosa was achieved after treatment for 7 days. The strain inhibited the reproduction of M. aeruginosa by impeding the synthesis of intracellular protein and carbohydrate of cyanobacterium, and only a very small part of intracellular protein and carbohydrate was detected after exposure to P. aeruginosa for 5 days. P. aeruginosa caused the alteration of intracellular antioxidant enzyme activity of M. aeruginosa, such as catalase, peroxidase. The accumulation of malondialdehyde aggravated membrane injury after treatment for 3 days. P. aeruginosa also affected the ion metabolism of cyanobacteria. The release of Na(+) and Cl(-) was significantly enhanced while the uptake of K(+), Ca(2+), Mg(2+), NO3(-) and SO4(2)(-) decreased. Surface morphology and intracellular structure of cyanobacteria and bacterial cells changed dramatically over time as evidenced by electron microscope (SEM) and transmission electron microscope (TEM) analysis. These results revealed that the algicidal activity of P. aeruginosa was primarily due to the fermentation liquid of P. aeruginosa that impeded the synthesis of intracellular protein and carbohydrate, and damaged the cell membrane through membrane lipid peroxidation. Copyright © 2016 Elsevier Inc. All rights reserved.

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.

Comparative in vitro activity of CGP 31608, a new penem antibiotic.

PubMed Central

Eliopoulos, G M; Wennersten, C; Reiszner, E; Moellering, R C

1987-01-01

The in vitro activity of a new penem antimicrobial agent, CGP 31608, was compared with those of imipenem, SCH 34343, and several other antimicrobial agents against approximately 600 bacterial isolates. CGP 31608 was active against gram-positive organisms, including methicillin-susceptible Staphylococcus aureus (MIC for 90% of the isolates [MIC90], 0.25 microgram/ml) and penicillin-susceptible streptococci (MIC90s, less than or equal to 2 micrograms/ml). Penicillin-resistant streptococci (including enterococci) and methicillin-resistant S. aureus were more resistant to the penem. Activities of CGP 31608 against members of the family Enterobacteriaceae were remarkably uniform, with MIC90s of 8 to 16 micrograms/ml. CGP 31608 was at least as active as imipenem and ceftazidime and more active than piperacillin against Pseudomonas aeruginosa. Drug activity was not influenced by the presence of any of 10 plasmid-mediated beta-lactamases. Against strains of Serratia marcescens, Enterobacter cloacae, and P. aeruginosa with derepressible chromosomally mediated beta-lactamases, the presence of cefoxitin did not induce increased resistance to CGP 31608. The new drug was also active against anaerobes (MIC90s, 0.25 to 8 micrograms/ml), Haemophilus influenzae (MIC90s, 0.5 to 1.0 micrograms/ml), and Legionella spp. (MIC90, 2 micrograms/ml). CGP 31608 showed an antibacterial spectrum similar to those of imipenem and SCH 34343 (except that the latter is not active against P. aeruginosa) but was generally less potent than these drugs. However, CGP 31608 demonstrated more activity (MIC90) than imipenem against P. aeruginosa, Pseudomonas cepacia, and methicillin-resistant Staphylococcus epidermidis and S. aureus. PMID:3498437

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

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.

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.

Phenomenon of resistance to Augmentin associated with sensitivity to ampicillin: occurrence and explanation.

PubMed Central

Brumfitt, W; Hamilton-Miller, J M; Dixson, S; Gargan, R A; Gooding, A

1983-01-01

Ampicillin was found to be some tenfold more active than amoxycillin against Enterobacter cloacae. This finding explains the observation that some Ent cloacae strains are sensitive to ampicillin in the disc test but resistant to Augmentin. Ampicillin was also found to be more active than amoxycillin against Citrobacter freundii and Serratia marcescens. In view of these findings, the practice of using ampicillin discs to predict sensitivity to amoxycillin should be reconsidered. The use of both ampicillin and amoxycillin discs is appropriate if errors are to be avoided. Images PMID:6343436

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)).

Global Molecular Epidemiology of IMP-Producing Enterobacteriaceae

PubMed Central

Peirano, Gisele; Motyl, Mary R.; Adams, Mark D.; Chen, Liang; Kreiswirth, Barry; DeVinney, Rebekah

2017-01-01

ABSTRACT International data on the molecular epidemiology of Enterobacteriaceae with IMP carbapenemases are lacking. We performed short-read (Illumina) whole-genome sequencing on a global collection of 38 IMP-producing clinical Enterobacteriaceae (2008 to 2014). IMP-producing Enterobacteriaceae (7 varieties within 11 class 1 integrons) were mainly present in the South Pacific and Asia. Specific blaIMP-containing integrons (In809 with blaIMP-4, In722 with blaIMP-6, and In687 with blaIMP-14) were circulating among different bacteria in countries such as Australia, Japan, and Thailand. In1312 with blaIMP-1 was present in Klebsiella pneumoniae from Japan and Citrobacter freundii from Brazil. Klebsiella pneumoniae (n = 22) was the most common species; clonal complex 14 (CC14) from Philippines and Japan was the most common clone and contained In1310 with blaIMP-26 and In1321 with blaIMP-6. The Enterobacter cloacae complex (n = 9) consisted of Enterobacter hormaechei and E. cloacae cluster III. CC78 (from Taiwan) containing In73 with blaIMP-8 was the most common clone among the E. cloacae complex. This study highlights the importance of surveillance programs using the latest molecular techniques for providing insight into the characteristics and global distribution of Enterobacteriaceae with blaIMP genes. PMID:28167555

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).

In vitro activity of tigecycline and comparator agents against a global collection of Gram-negative and Gram-positive organisms: tigecycline Evaluation and Surveillance Trial 2004 to 2007.

PubMed

Garrison, Mark W; Mutters, Reinier; Dowzicky, Michael J

2009-11-01

The Tigecycline Evaluation and Surveillance Trial began in 2004 to monitor the in vitro activity of tigecycline and comparator agents against a global collection of Gram-negative and Gram-positive pathogens. Against Gram negatives (n = 63 699), tigecycline MIC(90)'s ranged from 0.25 to 2 mg/L for Escherichia coli, Haemophilus influenzae, Acinetobacter baumannii, Klebsiella oxytoca, Enterobacter cloacae, Klebsiella pneumoniae, and Serratia marcescens (but was > or =32 for Pseudomonas aeruginosa). Against Gram-positive organisms (n = 32 218), tigecycline MIC(90)'s were between 0.06 and 0.25 mg/L for Streptococcus pneumoniae, Enterococcus faecium, Streptococcus agalactiae, Staphylococcus aureus, and Enterococcus faecalis. The in vitro activity of tigecycline was maintained against resistant phenotypes, including multidrug-resistant A. baumannii (9.2% of isolates), extended-spectrum beta-lactamase-producing E. coli (7.0%) and K. pneumoniae (14.0%), beta-lactamase-producing H. influenzae (22.2%), methicillin-resistant S. aureus (44.5%), vancomycin-resistant E. faecium (45.9%) and E. faecalis (2.8%), and penicillin-resistant S. pneumoniae (13.8%). Tigecycline represents a welcome addition to the armamentarium against difficult to treat organisms.

In vitro antimicrobial effects of a novel Pentaherbs concoction for atopic dermatitis.

PubMed

Hon, Kam Lun; Ip, Margaret; Wong, Chun Kwok; Chan, Ben Chung Lap; Leung, Ping Chung; Leung, Ting Fan

2018-05-01

In a series of bench and clinical trials, our group has determined the immunologic effects and clinical efficacy of a concoction of five herbal ingredients (PentaHerbs Formula, PHF) in treating children with atopic eczema (AE). This study investigates the antimicrobial effects that may be induced with PHF treatment. We investigated the effects of PHF on the minimal inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of Staphylococcus aureus and various bacteria that are commonly present on the skin of patients with AE. Staphylococcus aureus ATCC 25923, Methicllin resistant Staphylococcus aureus (MRSA) ATCC BAA-43, Enterococcus faecalis ATCC 29212, Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922, Enterobacter cloacae ATCC 13047, Proteus vulgaris ATCC 6380, and Acinetobacter baumannii ATCC 19606 were tested. PHF was more effective against Staphylococcus aureus ATCC 25923 and Methicllin resistant Staphylococcus aureus (MRSA) ATCC BAA-43. MIC and MBC were 1 and 25 mg/mL, respectively. PHF was more effective against Staphylococcus aureus ATCC 25923 and Methicllin resistant Staphylococcus aureus (MRSA) ATCC BAA-43t. PHF may be developed into a Staphylococcus aureus targeting topical application.

In Vitro Screening of an FDA-Approved Library Against ESKAPE Pathogens

PubMed Central

Younis, Waleed; AbdelKhalek, Ahmed; Mayhoub, Abdelrahman S.; Seleem, Mohamed N.

2017-01-01

Bacterial resistance to conventional antibiotics is an increasingly serious threat to public health worldwide that requires immediate exploration and the development of novel antimicrobial compounds. Drug repurposing is an inexpensive and untapped source of new antimicrobial leads, and it holds many attractive features warranting further attention for antimicrobial drug discovery. In an effort to repurpose drugs and explore new leads in the field of antimicrobial drug discovery, we performed a whole-cell screening assay of 1,600 Food and Drug Administration (FDA) approved drugs against Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter cloacae (ESKAPE) pathogens. The in vitro screening identified 49 non-antimicrobial drugs that were active against at least one species of ESKAPE pathogen. Although some of these drugs were known to have antibacterial activity, many have never been reported before. In particular, sulfonamide-containing structures represent a novel drug scaffold that should be investigated further. The characteristics of these drugs as antimicrobial agents may offer a safe, effective, and quick supplement to current approaches to treating bacterial infections. PMID:28190396

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.

Bactericidal efficacy of molybdenum oxide nanoparticles against antimicrobial-resistant pathogens.

PubMed

Lopes, E; Piçarra, S; Almeida, P L; de Lencastre, H; Aires-de-Sousa, M

2018-06-25

Multidrug-resistant bacteria pose a major threat to effective antibiotics and alternatives to fight multidrug-resistant pathogens are needed. We synthetized molybdenum oxide (MoO3) nanoparticles (NP) and determined their antibacterial activity against 39 isolates: (i) eight Staphylococcus aureus, including representatives of methicillin-resistant S. aureus epidemic clones; (ii) six enterococci, including vancomycin-resistant isolates; and (iii) 25 Gram-negative isolates (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, Enterobacter cloacae), including extended spectrum beta-lactamases and carbapenemases producers. All isolates showed a MoO3 NP MIC of 700-800 mg l -1 . MoO3 NP produced a clear inhibition zone for S. aureus and all Gram-negative isolates at concentrations ≥25 mg ml -1 and ≥50 mg ml -1 for enterococci. When the NP solutions were adjusted to pH ~7, the biocidal activity was completely abolished. MoO3 NP create an acidic pH and show a universal antimicrobial activity against susceptible and resistant isolates belonging to the most relevant bacterial species responsible for hospital-acquired infections.

Superinfections in herpes simplex keratitis.

PubMed

Boisjoly, H M; Pavan-Langston, D; Kenyon, K R; Baker, A S

1983-09-01

We reviewed 15 cases of culture-proven corneal superinfections in 15 patients (eight men and seven women ranging in age from 41 to 86 years) with recurrent herpes simplex keratitis. The factors that appeared to increase the risk of superinfection were the presence of an epithelial defect (found in all 15 cases), a history of recurrent herpetic keratouveitis (found in ten cases), and the use of topical corticosteroids (found in 13 cases). Eight of the 15 patients were taking antibiotics at the time the superinfections were diagnosed, indicating that topical antibiotics do not provide sufficient protection. Gram-negative rods were found in six cases (Proteus mirabilis, Pseudomonas aeruginosa, Serratia marcescens, Klebsiella oxytoca, Enterobacter cloacae, and Achromobacter sp.). Gram-positive organisms, often in association with another infecting agent, were found in six cases (Staphylococcus epidermidis, three cases; S. aureus, two cases; and Streptococcus sp., two cases). Fungal superinfections were found in three cases (Cephalosporium acremonium, Candida albicans, and Aspergillus fumigatus, one case each). Mycobacterium cheloni was found in two cases.

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.

Global Molecular Epidemiology of IMP-Producing Enterobacteriaceae.

PubMed

Matsumura, Yasufumi; Peirano, Gisele; Motyl, Mary R; Adams, Mark D; Chen, Liang; Kreiswirth, Barry; DeVinney, Rebekah; Pitout, Johann D D

2017-04-01

International data on the molecular epidemiology of Enterobacteriaceae with IMP carbapenemases are lacking. We performed short-read (Illumina) whole-genome sequencing on a global collection of 38 IMP-producing clinical Enterobacteriaceae (2008 to 2014). IMP-producing Enterobacteriaceae (7 varieties within 11 class 1 integrons) were mainly present in the South Pacific and Asia. Specific bla IMP -containing integrons (In809 with bla IMP-4 , In722 with bla IMP-6 , and In687 with bla IMP-14 ) were circulating among different bacteria in countries such as Australia, Japan, and Thailand. In1312 with bla IMP-1 was present in Klebsiella pneumoniae from Japan and Citrobacter freundii from Brazil. Klebsiella pneumoniae ( n = 22) was the most common species; clonal complex 14 (CC14) from Philippines and Japan was the most common clone and contained In1310 with bla IMP-26 and In1321 with bla IMP-6 The Enterobacter cloacae complex ( n = 9) consisted of Enterobacter hormaechei and E. cloacae cluster III. CC78 (from Taiwan) containing In73 with bla IMP-8 was the most common clone among the E. cloacae complex. This study highlights the importance of surveillance programs using the latest molecular techniques for providing insight into the characteristics and global distribution of Enterobacteriaceae with bla IMP genes. Copyright © 2017 American Society for Microbiology.

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.

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

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.

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

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".

Clonal Transmission of Gram-Negative Bacteria with Carbapenemases NDM-1, VIM-1, and OXA-23/72 in a Bulgarian Hospital.

PubMed

Pfeifer, Yvonne; Trifonova, Angelina; Pietsch, Michael; Brunner, Magdalena; Todorova, Iva; Gergova, Ivanka; Wilharm, Gottfried; Werner, Guido; Savov, Encho

2017-04-01

We characterized 72 isolates with reduced susceptibility to carbapenems (50 Acinetobacter spp., 13 Proteus mirabilis, five Escherichia coli, one Morganella morganii, one Enterobacter cloacae, one Providencia rettgeri, and one Pseudomonas aeruginosa) from a hospital in Sofia, Bulgaria. Different β-lactamase genes were identified by polymerase chain reaction and sequencing. Bacterial strain typing was performed by enzymatic macrorestriction and pulsed-field gel electrophoresis (PFGE) typing as well as multilocus sequence typing for selected isolates. The majority of Acinetobacter baumannii (46/50) and one Acinetobacter pittii isolate harbored carbapenemase genes bla OXA-23 or bla OXA-72 ; two A. baumannii contained both genes. PFGE typing of all A. baumannii showed the presence of nine different clones belonging to eight sequence types ST350, ST208, ST436, ST437, ST449, ST231, ST502, and ST579. Molecular characterization of the remaining isolates confirmed the presence of one NDM-1-producing E. coli-ST101 clone (five isolates) and one P. mirabilis clone (13 isolates) with VIM-1 and CMY-99. Furthermore, NDM-1 was identified in P. rettgeri and M. morganii and VIM-2 in the P. aeruginosa isolate. The permanent introduction of OXA-23/72 carbapenemase-producing A. baumannii clones into the hospital and the repeated occurrence of one VIM-1-producing P. mirabilis and one NDM-1-producing E. coli-ST101 clone over a period of more than 1 year is of concern and requires intensified investigations.

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.

Effect of pH, application technique, and chlorine-to-nitrogen ratio on disinfectant activity of inorganic chloramines with pure culture bacteria.

PubMed Central

Ward, N R; Wolfe, R L; Olson, B H

1984-01-01

The influence of pH, application technique, and chlorine-to-nitrogen weight ratio on the bactericidal activity of inorganic chloramine compounds was determined with stock and environmental strains of Escherichia coli, Salmonella spp., Pseudomonas aeruginosa, Klebsiella pneumoniae, and Enterobacter cloacae. The rate of inactivation increased from 1.5 to 2 times as the chlorine-to-nitrogen weight ratio was adjusted from 2:1 to 5:1, 5 to 6 times as the pH was decreased from 8 to 6, and 5 to 6 times as the concentration was increased from 1 to 5 mg/liter. Separate additions of free chlorine and ammonia (concurrent addition and preammoniation) into seeded water at or below pH 7.5 resulted in killing comparable to that observed with free chlorine (99% inactivation in less than 20 s). At pH 8, inactivation by separate additions was considerably slower and was comparable to that by prereacted chloramine compounds (99% inactivation in 25 to 26 min). Determination of the effectiveness of inorganic chloramine compounds as primary disinfectants for drinking water must consider the method of application, pH and concentrations of chlorine and ammonia. PMID:6437328

In Vitro Screening of an FDA-Approved Library Against ESKAPE Pathogens.

PubMed

Younis, Waleed; AbdelKhalek, Ahmed; Mayhoub, Abdelrahman S; Seleem, Mohamed N

2017-01-01

Bacterial resistance to conventional antibiotics is an increasingly serious threat to public health worldwide that requires immediate exploration and the development of novel antimicrobial compounds. Drug repurposing is an inexpensive and untapped source of new antimicrobial leads, and it holds many attractive features warranting further attention for antimicrobial drug discovery. In an effort to repurpose drugs and explore new leads in the field of antimicrobial drug discovery, we performed a whole-cell screening assay of 1,600 Food and Drug Administration (FDA) approved drugs against Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter cloacae (ESKAPE) pathogens. The in vitro screening identified 49 non-antimicrobial drugs that were active against at least one species of ESKAPE pathogen. Although some of these drugs were known to have antibacterial activity, many have never been reported before. In particular, sulfonamide-containing structures represent a novel drug scaffold that should be investigated further. The characteristics of these drugs as antimicrobial agents may offer a safe, effective, and quick supplement to current approaches to treating bacterial infections. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Eliciting antibiotics active against the ESKAPE pathogens in a collection of actinomycetes isolated from mountain soils.

PubMed

Zhu, Hua; Swierstra, Jasper; Wu, Changsheng; Girard, Geneviève; Choi, Young Hae; van Wamel, Willem; Sandiford, Stephanie K; van Wezel, Gilles P

2014-08-01

The rapid emergence of multidrug-resistant (MDR) bacterial pathogens poses a major threat for human health. In recent years, genome sequencing has unveiled many poorly expressed antibiotic clusters in actinomycetes. Here, we report a well-defined ecological collection of >800 actinomycetes obtained from sites in the Himalaya and Qinling mountains, and we used these in a concept study to see how efficiently antibiotics can be elicited against MDR pathogens isolated recently from the clinic. Using 40 different growth conditions, 96 actinomycetes were identified - predominantly Streptomyces - that produced antibiotics with efficacy against the MDR clinical isolates referred to as ESKAPE pathogens: Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and/or Enterobacter cloacae. Antimicrobial activities that fluctuated strongly with growth conditions were correlated with specific compounds, including borrelidin, resistomycin, carbomethoxy-phenazine, and 6,7,8- and 5,6,8-trimethoxy-3-methylisocoumarin, of which the latter was not described previously. Our work provided insights into the potential of actinomycetes as producers of drugs with efficacy against clinical isolates that have emerged recently and also underlined the importance of targeting a specific pathogen. © 2014 The Authors.

Preliminary survey of local bacteriophages with lytic activity against multi-drug resistant bacteria.

PubMed

Latz, Simone; Wahida, Adam; Arif, Assuda; Häfner, Helga; Hoß, Mareike; Ritter, Klaus; Horz, Hans-Peter

2016-10-01

Bacteriophages (phages) represent a potential alternative for combating multi-drug resistant bacteria. Because of their narrow host range and the ever emergence of novel pathogen variants the continued search for phages is a prerequisite for optimal treatment of bacterial infections. Here we performed an ad hoc survey in the surroundings of a University hospital for the presence of phages with therapeutic potential. To this end, 16 aquatic samples of different origins and locations were tested simultaneously for the presence of phages with lytic activity against five current, but distinct strains each from the ESKAPE-group (i.e., Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter cloacae). Phages could be isolated for 70% of strains, covering all bacterial species except S. aureus. Apart from samples from two lakes, freshwater samples were largely devoid of phages. By contrast, one liter of hospital effluent collected at a single time point already contained phages active against two-thirds of tested strains. In conclusion, phages with lytic activity against nosocomial pathogens are unevenly distributed across environments with the prime source being the immediate hospital vicinity. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bacteriological quality of the wastewater used for irrigation at the vegetable farms in Korle-bu Teaching Hospital, Accra Metropolis, Ghana.

PubMed

Pesewu, George A; Bentum, Daniel; Olu-Taiwo, Michael A; Glover, Kathreen K; Yirenya-Tawiah, Dzidzo R

2017-01-01

Many developing countries, including Ghana, are water stressed. As such, farmers, particularly those in urban areas, have adopted the use of wastewater for irrigation. This study evaluated the bacteriological water quality of the wastewater used for irrigation in the vegetable farms at Korle-Bu Teaching Hospital (KBTH), Accra Metropolis, Ghana. In all, 40 wastewater samples were collected and analysed bacteriologically using the total aerobic plate count method. The isolated bacteria were identified biochemically using Bergey's manual for determinative bacteriology. Mean total bacterial colony count values in the range of 2.75-4.44 × 10 5 CFU/100 mL were isolated which far exceeds values of 1 × 10 3 /100 mL recommended by the World Health Organization (WHO) for unrestricted irrigation of crops likely to be eaten raw. Enterobacter cloacae (51.4%), Klebsiella sp. (24.1%), Pseudomonas aeruginosa (11.3%), Salmonella typhi (10.6%), Escherichia coli (2.2%) and Proteus sp. (0.4%) were the predominant bacteria isolated. Growers should use treated wastewater for farming while processors and consumers should minimize contamination risks of produce from the vegetable farms/garden to the plate. © The Author(s) 2016.

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.

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-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.

Genomic epidemiology of global VIM-producing Enterobacteriaceae.

PubMed

Matsumura, Yasufumi; Peirano, Gisele; Devinney, Rebekah; Bradford, Patricia A; Motyl, Mary R; Adams, Mark D; Chen, Liang; Kreiswirth, Barry; Pitout, Johann D D

2017-08-01

International data on the molecular epidemiology of Enterobacteriaceae with VIM carbapenemases are limited. We performed short read (Illumina) WGS on a global collection of 89 VIM-producing clinical Enterobacteriaceae (2008-14). VIM-producing (11 varieties within 21 different integrons) isolates were mostly obtained from Europe. Certain integrons with bla VIM were specific to a country in different species and clonal complexes (CCs) (In 87 , In 624 , In 916 and In 1323 ), while others had spread globally among various Enterobacteriaceae species (In 110 and In 1209 ). Klebsiella pneumoniae was the most common species ( n  = 45); CC147 from Greece was the most prevalent clone and contained In 590 -like integrons with four different bla VIM s. Enterobacter cloacae complex was the second most common species and mainly consisted of Enterobacter hormaechei ( Enterobacter xiangfangensis , subsp. steigerwaltii and Hoffmann cluster III). CC200 (from Croatia and Turkey), CC114 (Croatia, Greece, Italy and the USA) and CC78 (from Greece, Italy and Spain) containing bla VIM-1 were the most common clones among the E. cloacae complex. This study highlights the importance of surveillance programmes using the latest molecular techniques in providing insight into the characteristics and global distribution of Enterobacteriaceae with bla VIM s. © The Author 2017. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

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

Enterobacter sp. 638 is an endophytic plant growth promoting gamma-proteobacterium that was isolated from the stem of poplar (Populus trichocarpa x 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 plantmore » 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

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.

Two Novel Algicidal Isolates Kill Chlorella pyrenoidosa by Inhibiting their Host Antioxidase Activities.

PubMed

Liao, Chunli; Liu, Xiaobo; Liu, Ruifang; Shan, Linna

2015-09-01

In the biocontrol of harmful algal blooms, there has been considerable interest about the role of algicidal bacteria in algicidal activity. In this experiment, two novel algicidal bacteria (strains NP23 and AM11) against Chlorella pyrenoidosa were isolated from the Baiguishan reservoir in China. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strains NP23 and AM11 belonged to Enterobacter cloacae and Gibberella moniliformis, respectively. To further understand the algicidal activities, five parameters including the chlorophyll a content, cell survival rate, superoxide dismutase (SOD) peroxide dismutase (POD), and catalase (CAT) were tested in the C. pyrenoidosa cells after inoculation with the algicidal bacteria Enterobacter cloacae NP23 and Gibberella moniliformis AM11. As a result, the growth of the treated C. pyrenoidosa was significantly restrained with a great decline of chlorophyll a content. Meanwhile, three antioxidase activities of the treated C. pyrenoidosa were initially stimulated from day 1 to day 3 but then dramatically inhibited at low level. These results induced that the oxidative imbalance (i.e., inhibition of antioxidase activities) caused by algicidal bacteria could be the killing agent of the C. pyrenoidosa cells.

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

New Mouse Model for Chronic Infections by Gram-Negative Bacteria Enabling the Study of Anti-Infective Efficacy and Host-Microbe Interactions

PubMed Central

Pletzer, Daniel; Mansour, Sarah C.; Wuerth, Kelli; Rahanjam, Negin

2017-01-01

ABSTRACT Only a few, relatively cumbersome animal models enable long-term Gram-negative bacterial infections that mimic human situations, where untreated infections can last for weeks. Here, we describe a simple murine cutaneous abscess model that enables chronic or progressive infections, depending on the subcutaneously injected bacterial strain. In this model, Pseudomonas aeruginosa cystic fibrosis epidemic isolate LESB58 caused localized high-density skin and soft tissue infections and necrotic skin lesions for up to 10 days but did not disseminate in either CD-1 or C57BL/6 mice. The model was adapted for use with four major Gram-negative nosocomial pathogens, Acinetobacter baumannii, Klebsiella pneumoniae, Enterobacter cloacae, and Escherichia coli. This model enabled noninvasive imaging and tracking of lux-tagged bacteria, the influx of activated neutrophils, and production of reactive oxygen-nitrogen species at the infection site. Screening antimicrobials against high-density infections showed that local but not intravenous administration of gentamicin, ciprofloxacin, and meropenem significantly but incompletely reduced bacterial counts and superficial tissue dermonecrosis. Bacterial RNA isolated from the abscess tissue revealed that Pseudomonas genes involved in iron uptake, toxin production, surface lipopolysaccharide regulation, adherence, and lipase production were highly upregulated whereas phenazine production and expression of global activator gacA were downregulated. The model was validated for studying virulence using mutants of more-virulent P. aeruginosa strain PA14. Thus, mutants defective in flagella or motility, type III secretion, or siderophore biosynthesis were noninvasive and suppressed dermal necrosis in mice, while a strain with a mutation in the bfiS gene encoding a sensor kinase showed enhanced invasiveness and mortality in mice compared to controls infected with wild-type P. aeruginosa PA14. PMID:28246361

Complete genome sequence of Enterobacter aerogenes KCTC 2190.

PubMed

Shin, Sang Heum; Kim, Sewhan; Kim, Jae Young; Lee, Soojin; Um, Youngsoon; Oh, Min-Kyu; Kim, Young-Rok; Lee, Jinwon; Yang, Kap-Seok

2012-05-01

This is the first complete genome sequence of the Enterobacter aerogenes species. Here we present the genome sequence of E. aerogenes KCTC 2190, which contains 5,280,350 bp with a G + C content of 54.8 mol%, 4,912 protein-coding genes, and 109 structural RNAs.

Transmission of Enterobacter aerogenes septicemia in healthcare workers.

PubMed

Jha, Piyush; Kim, Choon-Mee; Kim, Dong-Min; Chung, Jong-Hoon; Yoon, Na-Ra; Jha, Babita; Kim, Seok Won; Jang, Sook Jin; Ahn, Young-Joon; Chung, Jae Keun; Jeon, Doo Young

2016-01-01

Enterobacter aerogenes is recognized as an important bacterial pathogen in hospital-acquired infections. This report describes two unusual cases of septicemia caused by E. aerogenes in immunocompetent healthcare workers. E. aerogenes was isolated from blood cultures of the two patients experiencing septicemia. The clinical isolates were initially identified as E. aerogenes using a VITEK II automated system and 16S rRNA sequence analysis, and; both isolates involved in the outbreak shared a common pulse-field gel electrophoresis pattern. The similarities between the two cases included the simultaneous development of gastroenteritis symptoms, severe sepsis and thrombocytopenia after taking intravenous injections of ketorolac tromethamine. A common source of normal saline, a 100 mL bottle, was used for diluting the analgesic in both cases. In addition to the general population, healthcare workers, especially those who are also intravenous drug abusers, should be considered subjects that could cause a transmission of Enterobacter infection.

Antibacterial potential of silver nanoparticles against isolated urinary tract infectious bacterial pathogens

NASA Astrophysics Data System (ADS)

Jacob Inbaneson, Samuel; Ravikumar, Sundaram; Manikandan, Nachiappan

2011-12-01

The silver nanoparticles were synthesized by chemical reduction method and the nanoparticles were characterized using ultraviolet-visible (UV-Vis) absorption spectroscopy and X-ray diffraction (XRD) studies. The synthesized silver nanoparticles were investigated to evaluate the antibacterial activity against urinary tract infectious (UTIs) bacterial pathogens. Thirty-two bacteria were isolated from mid urine samples of 25 male and 25 female patients from Thondi, Ramanathapuram District, Tamil Nadu, India and identified by conventional methods. Escherichia coli was predominant (47%) followed by Pseudomonas aeruginosa (22%), Klebsiella pneumoniae (19%), Enterobacter sp. (6%), Proteus morganii (3%) and Staphylococcus aureus (3%). The antibacterial activity of silver nanoparticles was evaluated by disc diffusion assay. P. aeruginosa showed maximum sensitivity (11 ± 0.58 mm) followed by Enterobacter sp. (8 ± 0.49 mm) at a concentration of 20 μg disc-1 and the sensitivity was highly comparable with the positive control kanamycin and tetracycline. K. pneumoniae, E. coli, P. morganii and S. aureus showed no sensitivity against all the tested concentrations of silver nanoparticles. The results provided evidence that, the silver nanoparticles might indeed be the potential sources to treat urinary tract infections caused by P. aeruginosa and Enterobacter sp.

Surveillance of Wisconsin Antibacterial Susceptibility Patterns.

PubMed

Munson, Erik; Block, Timothy K; Bowles, Erin J; Costello, Michael; Dern, Richard; Fritsche, Thomas R; Helgesen, Michael A; Kropp, Joshua L; Podzorski, Raymond P; Siebers, Karen; Simmons, Brian; Smith, Mary A; Spray, Frances; Van, Tam T; Warshauer, David M

2016-02-01

Antimicrobial resistance presents a threat to quality patient care. Knowledge of localantibacterial susceptibility patterns can guide clinicians in empiric antibacterial administration andassist pharmacists and infectious disease physicians in development of appropriate therapeutic pathways. To characterize Wisconsin antibacterial susceptibility patterns and elucidate geographicor temporal variation in antibacterial resistance, a retrospective, observational analysis of antibiogram data was performed. Seventy-two members of the Wisconsin Clinical Laboratory Network(WCLN) submitted antibiograms describing clinically significant isolates tested in calendar year 2013 to the WCLN Laboratory Technical Advisory Group. In the context of commonly reported antibacterial agents, data were compiled for approximately 75,800 isolates of Escherichia coi; 13,300 Klebsiella pneumoniae; 6300 Proteus mirobilis;2800 Enterobacter cloacae; 8400 Pseudomonas aeruginosa; 30,000 S aureus; 11,200 coagulase-negative Staphylococcus spp; and 13,800 Enterococcus spp. P mirobilis isolates from northern Wisconsin were more likely to demonstrate resistance than those in the southern region. In contrast, P aeruginosa isolates from southern Wisconsin had decreased susceptibility to a number ofagents when compared to other regions. Temporal trending in decreased E coli and P mirabilis susceptibility to fluoroquinolones and trimethoprimsulfamethoxazole was observed. Increased methicillin-resistant Staphylococcus oureus (MRSA) rates were observed in northwest and southeastWisconsin. In general, northeast Wisconsin exhibited less frequency of antibacterial resistance. Geographic variation exists with respect to antibacterial resistance, particularly inareas of Wisconsin adjacent to large population centers of neighboring states. Antibacterial surveillance in Wisconsin is indicated on a regular basis to assess emerging trends in antibacterial resistance. Existing WCLN infrastructure allows for such

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.

In vitro activity and stability against novel beta-lactamases of investigational beta-lactams (cefepime, cefpirome, flomoxef, SCE2787 and piperacillin plus tazobactam) in comparison with established compounds (cefotaxime, latamoxef and piperacillin).

PubMed

Bauernfeind, A; Schweighart, S; Eberlein, E; Jungwirth, R

1991-01-01

The therapeutic perspectives of flomoxef, SCE 2787, cefpirome, cefepime, latamoxef, cefotaxime and of piperacillin plus tazobactam were comparatively evaluated by their in vitro activity against 1119 clinical isolates of 83 bacterial species. Escherichia coli, Klebsiella spp. Enterobacter sakazakii, Proteus spp. and Shigella spp. were about equally susceptible to the cephalosporins (MIC90: 0.06 to 0.5 mg/l), while the MIC90 for piperacillin plus tazobactam was between 2 and 16 mg/l. Enterobacter cloacae, Enterobacter aerogenes and Serratia spp. were most susceptible to SCE 2787, cefpirome and cefepime (MIC90: 0.06 to 2 mg/l) followed by latamoxef, cefotaxime, flomoxef and piperacillin plus tazobactam. For Citrobacter spp., Providencia spp. and Yersinia enterocolitica MIC90 were between 0.06 and 0.5 mg/l. Flomoxef was between 2 to 4 log2 less active against these species but more active than piperacillin plus tazobactam (MIC90: 2 and 8 mg/l). Morganella morganii and Hafnia alvei were most susceptible to cefepime, cefpirome and latamoxef (MIC90: 0.13 to 0.5 mg/l) while cefotaxime (MIC90: 8 mg/l) and piperacillin plus tazobactam (MIC90: 8 and greater than 64 mg/l) were the least active compounds. SCE 2787, cefepime and cefpirome were the most potent beta-lactams against the majority of the 13 species of non-fermentative bacilli (NFB) investigated (MIC90: 0.5 to 16 mg/l). The oxacephems were the least active compounds against NFB. Cefepime was the most active of the compounds included against Pseudomonas aeruginosa (MIC90: 16 mg/l). Haemophilus spp., Neisseria gonorrhoeae and Bordetella pertussis were most susceptible to cefotaxime (MIC90: 0.03 to 0.06 mg/l). Latamoxef had the lowest activity of all compounds against gram-positive cocci. Flomoxef was the most active compound against penicillinase producing Staphylococcus aureus and about equally active as the other betalactams against methicillin susceptible staphylococci of other staphylococcal species

[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

In vitro activity of imipenem/relebactam against Gram-negative ESKAPE pathogens isolated in 17 European countries: 2015 SMART surveillance programme.

PubMed

Karlowsky, James A; Lob, Sibylle H; Kazmierczak, Krystyna M; Hawser, Stephen P; Magnet, Sophie; Young, Katherine; Motyl, Mary R; Sahm, Daniel F

2018-04-11

Relebactam is an inhibitor of class A β-lactamases, including KPC β-lactamases, and class C β-lactamases, and is currently under clinical development in combination with imipenem. The objective of the current study was to evaluate the in vitro activity of imipenem/relebactam against Gram-negative ESKAPE pathogens (Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp.) submitted by clinical laboratories in 17 European countries to the Study for Monitoring Antimicrobial Resistance Trends (SMART) global surveillance programme in 2015. MICs were determined using the CLSI standard broth microdilution method and interpreted using EUCAST clinical breakpoints. Relebactam was tested at a fixed concentration of 4 mg/L in combination with doubling dilutions of imipenem. Imipenem/relebactam MICs were interpreted using breakpoints for imipenem. Rates of susceptibility to imipenem and imipenem/relebactam for isolates of P. aeruginosa (n = 1705), K. pneumoniae (n = 1591) and Enterobacter spp. (n = 772) were 72.0/94.7%, 88.7/94.8% and 95.6/96.8%, respectively. Relebactam restored imipenem susceptibility to 81.1%, 54.2% and 26.5% of imipenem-non-susceptible isolates of P. aeruginosa (n = 477), K. pneumoniae (n = 179) and Enterobacter spp. (n = 34). Most imipenem/relebactam-non-susceptible isolates carried MBLs, OXA-48 or GES carbapenemases. Relebactam did not increase the number of isolates of A. baumannii (n = 486) susceptible to imipenem. Relebactam restored susceptibility to imipenem for the majority of imipenem-non-susceptible isolates of P. aeruginosa and K. pneumoniae tested as well as some isolates of imipenem-non-susceptible Enterobacter spp. Based on our results, imipenem/relebactam appears to be a promising therapeutic option for treating patients with infections caused by antimicrobial-resistant Gram-negative bacilli.

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.

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.

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

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

Medicinal Plants Used by a Mbyá-Guarani Tribe Against Infections: Activity on KPC-Producing Isolates and Biofilm-Forming Bacteria.

PubMed

Brandelli, Clara Lia Costa; Ribeiro, Vanessa Bley; Zimmer, Karine Rigon; Barth, Afonso Luís; Tasca, Tiana; Macedo, Alexandre José

2015-11-01

The traditional use of medicinal plants for treatment of infectious diseases by an indigenous Mbyá-Guarani tribe from South Brazil was assessed by evaluating the antibiotic and antibiofilm activities against relevant bacterial pathogens. Aqueous extracts from 10 medicinal plants were prepared according to indigenous Mbyá-Guarani traditional uses. To evaluate antibiotic (OD600) and antibiofilm (crystal violet method) activities, Pseudomonas aeruginosa ATCC 27853, Staphylococcus epidermidis ATCC 35984 and seven multi-drug resistant Klebsiella pneumoniae carbapenemase (KPC)-producing bacterial clinical isolates were challenged with the extracts. Furthermore, the susceptibility profile of KPC-producing bacteria and the ability of these isolates to form biofilm were evaluated. The plants Campomanesia xanthocarpa, Maytenus ilicifolia, Bidens pilosa and Verbena sp. showed the best activity against bacterial growth and biofilm formation. The majority of KPC-producing isolates, which showed strong ability to form biofilm and a multidrug resistance profile, was inhibited by more than 50% by some extracts. The Enterobacter cloacae (KPC 05) clinical isolate was the only one resistant to all extracts. This study confirms the importance of indigenous traditional medicinal knowledge and describes for the first time the ability of these plants to inhibit biofilm formation and/or bacterial growth of multi-drug resistant KPC-producing isolates.

Kombucha fermentation and its antimicrobial activity.

PubMed

Sreeramulu, G; Zhu, Y; Knol, W

2000-06-01

Kombucha was prepared in a tea broth (0.5% w/v) supplemented with sucrose (10% w/v) by using a commercially available starter culture. The pH decreased steadily from 5 to 2.5 during the fermentation while the weight of the "tea fungus" and the OD of the tea broth increased through 4 days of the fermentation and remained fairly constant thereafter. The counts of acetic acid-producing bacteria and yeasts in the broth increased up to 4 days of fermentation and decreased afterward. The antimicrobial activity of Kombucha was investigated against a number of pathogenic microorganisms. Staphylococcus aureus, Shigella sonnei, Escherichia coli, Aeromonas hydrophila, Yersinia enterolitica, Pseudomonas aeruginosa, Enterobacter cloacae, Staphylococcus epidermis, Campylobacter jejuni, Salmonella enteritidis, Salmonella typhimurium, Bacillus cereus, Helicobacterpylori, and Listeria monocytogenes were found to be sensitive to Kombucha. According to the literature on Kombucha, acetic acid is considered to be responsible for the inhibitory effect toward a number of microbes tested, and this is also valid in the present study. However, in this study, Kombucha proved to exert antimicrobial activities against E. coli, Sh. sonnei, Sal. typhimurium, Sal. enteritidis, and Cm. jejuni, even at neutral pH and after thermal denaturation. This finding suggests the presence of antimicrobial compounds other than acetic acid and large proteins in Kombucha.

Characterization and purification of a bacteriocin from Lactobacillus paracasei subsp. paracasei BMK2005, an intestinal isolate active against multidrug-resistant pathogens.

PubMed

Bendjeddou, Kamel; Fons, Michel; Strocker, Pierre; Sadoun, Djamila

2012-04-01

A strain of Lactobacillus paracasei subsp. paracasei BMK2005 isolated from healthy infant faeces has shown a remarkable antibacterial activity against 32 bacterial pathogenic strains of human clinical isolates. Among them, 13 strains belonging to species of Escherichia coli, Citrobacter freundii, Citrobacter diversus, Klebsiella oxytoca, Enterobacter cloacae and Pseudomonas aeruginosa were resistant to Cefotaxime (CTX) and Ceftazidime (CAZ), and 4 strains of Staphylococcus aureus were resistant to Methicillin (MRSA). This antibacterial activity was attributed to a bacteriocin designated as Paracaseicin A. It was heat-stable up to 120°C for 5 min and active within the pH range of 2-5. Its activity was lost when treated with proteases, which reveals its proteinaceous nature. This bacteriocin was successfully purified only by two steps of reversed phase chromatography. Its molecular mass, determined by mass spectrometry analysis, was 2,462.5 Da. To our knowledge, the present study is the first report on characterization and purification of a bacteriocin, produced by a L. paracasei subsp. paracasei strain exhibiting an antibacterial activity against various multidrug-resistant species of Gram-positive and Gram-negative bacteria, which reveals its potential for use in prevention or treatment of infections caused by multidrug-resistant species especially in cases of antibiotics-associated diarrhea (AAD).

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

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.

Streptosporangium minutum sp. nov., isolated from garden soil exposed to microwave radiation.

PubMed

Le Roes-Hill, Marilize; Durrell, Kim; Prins, Alaric; Meyers, Paul R

2018-06-01

The actinobacterium, strain M26 T , was isolated from garden soil that was pre-treated with microwave radiation. The soil sample was collected in Roodepoort, Gauteng Province, South Africa as part of an antibiotic-screening programme. The isolate produced branched vegetative mycelium with sporangiophores bearing small sporangia ranging from 3 to 6 μm in diameter. Rapid genus identification revealed that the isolate belongs to the genus Streptosporangium. To confirm this result, the strain was subjected to polyphasic taxonomic characterisation. Chemotaxonomic characteristics were as follows: meso-DAP in the peptidoglycan, the whole-cell hydrolysate yielded madurose, predominant menaquinones were MK9 (21%), MK9(H 2 ) (40%), MK9(H 4 ) (31%) and MK9(H 6 ) (3%); the polar lipid profile included an aminolipid, phosphoglycolipids, phosphatidylethanolamine, and phosphatidylmonomethylethanolamine. In addition, the fatty acid profile showed the presence of C 16:0 (12.8%), C 17:1 ω8c (14.2%), and 10-methyl-C 17:0 (15.8%). Furthermore, 16S rRNA gene sequence phylogenetic analysis showed that the strain is closely related to members of the genus Streptosporangium, which supports its classification within the family Streptosporangiaceae. Strain M26 T exhibited antibiosis against a range of pathogenic bacteria, including, but not limited to Acinetobacter baumannii ATCC 19606 T , Enterobacter cloacae subsp. cloacae ATCC BAA-1143, Enterococcus faecalis ATCC 51299 (vancomycin resistant), Escherichia coli ATCC 25922, Listeria monocytogenes ATCC 19111, Mycobacterium tuberculosis H37Rv T , Pseudomonas aeruginosa ATCC 27853, Salmonella enterica subsp. arizonae ATCC 13314 T , and the methicillin-resistant Staphylococcus aureus subsp. aureus ATCC 33591 (MRSA). The name Streptosporangium minutum is proposed with the type strain M26 T (=LMG 28850 T =NRRL B-65295 T ).

Pseudomonas aeruginosa Trent and zinc homeostasis.

PubMed

Davies, Corey B; Harrison, Mark D; Huygens, Flavia

2017-09-01

Pseudomonas aeruginosa is a Gram-negative pathogen and the major cause of mortality in patients with cystic fibrosis. The mechanisms that P. aeruginosa strains use to regulate intracellular zinc have an effect on infection, antibiotic resistance and the propensity to form biofilms. However, zinc homeostasis in P. aeruginosa strains of variable infectivity has not been compared. In this study, zinc homeostasis in P. aeruginosa Trent, a highly infectious clinical strain, was compared to that of a laboratory P. aeruginosa strain, ATCC27853. Trent was able to tolerate higher concentrations of additional zinc in rich media than ATCC27853. Further, pre-adaptation to additional zinc enhanced the growth of Trent at non-inhibitory concentrations but the impact of pre-adaption on the growth of ATCC27853 under the same conditions was minimal. The results establish clear differences in zinc-induced responses in Trent and ATCC27853, and how zinc homeostasis can be a promising target for the development of novel antimicrobial strategies for P. aeruginosa infection in cystic fibrosis patients. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

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

The occurrence of CTX-M-25-producing Enterobacteriaceae in day-old broiler chicks in Japan.

PubMed

Yossapol, Montira; Sugiyama, Michiyo; Asai, Tetsuo

2017-10-07

Day-old chicks from 3 hatcheries were placed on bedding paper and brought to a commercial broiler farm between January and July 2016. Sixty-six samples of the paper, which were stained with meconium droppings of the chicks, were collected and examined for isolation of cephalosporin-resistant Enterobacteriaceae. Cefotaxime (CTX)-resistant Klebsiella pneumoniae (1 isolate) and Enterobacter cloacae (4 isolates) were isolated from 5 (7.58%) of the 66 samples. Conjugation experiments revealed that the bla CTX-M-25 gene conferring CTX resistance was transferred from the K. pneumoniae isolate and 2 of the 4 E. cloacae isolates to Escherichia coli DH5α via IncA/C plasmids carrying the gene. Our results suggested that the bla CTX-M-25 gene originating from chicks may be spread among commercial broiler farms.

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.

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

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.

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.

Multiyear, Multinational Survey of the Incidence and Global Distribution of Metallo-β-Lactamase-Producing Enterobacteriaceae and Pseudomonas aeruginosa.

PubMed

Kazmierczak, Krystyna M; Rabine, Sharon; Hackel, Meredith; McLaughlin, Robert E; Biedenbach, Douglas J; Bouchillon, Samuel K; Sahm, Daniel F; Bradford, Patricia A

2016-02-01

Metallo-β-lactamases (MBLs) hydrolyze all classes of β-lactams except monobactams and are not inhibited by classic serine β-lactamase inhibitors. Gram-negative pathogens isolated from patient infections were collected from 202 medical centers in 40 countries as part of a global surveillance study from 2012 to 2014. Carbapenem-nonsusceptible Enterobacteriaceae and Pseudomonas aeruginosa were characterized for bla genes encoding VIM, IMP, NDM, SPM, and GIM variants using PCR and sequencing. A total of 471 MBL-positive isolates included the following species (numbers of isolates are in parentheses): P. aeruginosa (308), Klebsiella spp. (85), Enterobacter spp. (39), Proteeae (16), Citrobacter freundii (12), Escherichia coli (6), and Serratia marcescens (5) and were submitted by sites from 34 countries. Of these, 69.6% were collected in 9 countries (numbers of isolates are in parentheses): Russia (72), Greece (61), Philippines (54), Venezuela (29), and Kuwait, Nigeria, Romania, South Africa, and Thailand (20 to 25 isolates each). Thirty-two different MBL variants were detected (14 VIM, 14 IMP, and 4 NDM enzymes). Seven novel MBL variants were encountered in the study, each differing from a previously reported variant by one amino acid substitution: VIM-42 (VIM-1 [V223I]), VIM-43 (VIM-4 [A24V]), VIM-44 (VIM-2 [K257N]), VIM-45 (VIM-2 [T35I]), IMP-48 (IMP-14 [I69T]), IMP-49 (IMP-18 [V49F]), and NDM-16 (NDM-1 [R264H]). The in vitro activities of all tested antibiotics against MBL-positive Enterobacteriaceae were significantly reduced with the exception of that of aztreonam-avibactam (MIC90, 0.5 to 1 μg/ml), whereas colistin was the most effective agent against MBL-positive P. aeruginosa isolates (>97% susceptible). Although the global percentage of isolates encoding MBLs remains relatively low, their detection in 12 species, 34 countries, and all regions participating in this surveillance study is concerning. Copyright © 2016, American Society for Microbiology. All

Multiyear, Multinational Survey of the Incidence and Global Distribution of Metallo-β-Lactamase-Producing Enterobacteriaceae and Pseudomonas aeruginosa

PubMed Central

Rabine, Sharon; Hackel, Meredith; McLaughlin, Robert E.; Biedenbach, Douglas J.; Bouchillon, Samuel K.; Sahm, Daniel F.; Bradford, Patricia A.

2015-01-01

Metallo-β-lactamases (MBLs) hydrolyze all classes of β-lactams except monobactams and are not inhibited by classic serine β-lactamase inhibitors. Gram-negative pathogens isolated from patient infections were collected from 202 medical centers in 40 countries as part of a global surveillance study from 2012 to 2014. Carbapenem-nonsusceptible Enterobacteriaceae and Pseudomonas aeruginosa were characterized for bla genes encoding VIM, IMP, NDM, SPM, and GIM variants using PCR and sequencing. A total of 471 MBL-positive isolates included the following species (numbers of isolates are in parentheses): P. aeruginosa (308), Klebsiella spp. (85), Enterobacter spp. (39), Proteeae (16), Citrobacter freundii (12), Escherichia coli (6), and Serratia marcescens (5) and were submitted by sites from 34 countries. Of these, 69.6% were collected in 9 countries (numbers of isolates are in parentheses): Russia (72), Greece (61), Philippines (54), Venezuela (29), and Kuwait, Nigeria, Romania, South Africa, and Thailand (20 to 25 isolates each). Thirty-two different MBL variants were detected (14 VIM, 14 IMP, and 4 NDM enzymes). Seven novel MBL variants were encountered in the study, each differing from a previously reported variant by one amino acid substitution: VIM-42 (VIM-1 [V223I]), VIM-43 (VIM-4 [A24V]), VIM-44 (VIM-2 [K257N]), VIM-45 (VIM-2 [T35I]), IMP-48 (IMP-14 [I69T]), IMP-49 (IMP-18 [V49F]), and NDM-16 (NDM-1 [R264H]). The in vitro activities of all tested antibiotics against MBL-positive Enterobacteriaceae were significantly reduced with the exception of that of aztreonam-avibactam (MIC90, 0.5 to 1 μg/ml), whereas colistin was the most effective agent against MBL-positive P. aeruginosa isolates (>97% susceptible). Although the global percentage of isolates encoding MBLs remains relatively low, their detection in 12 species, 34 countries, and all regions participating in this surveillance study is concerning. PMID:26643349

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.

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.

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.

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.

mar Operon Involved in Multidrug Resistance of Enterobacter aerogenes

PubMed Central

Chollet, Renaud; Bollet, Claude; Chevalier, Jacqueline; Malléa, Monique; Pagès, Jean-Marie; Davin-Regli, Anne

2002-01-01

We determined the sequence of the entire marRAB operon in Enterobacter aerogenes. It is functionally and structurally analogous to the Escherichia coli operon. The overexpression of E. aerogenes MarA induces a multidrug resistance phenotype in a susceptible strain, demonstrated by a noticeable resistance to various antibiotics, a decrease in immunodetected porins, and active efflux of norfloxacin. PMID:11897595

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

Intraoperative vancomycin use in spinal surgery: single institution experience and microbial trends.

PubMed

Ghobrial, George M; Thakkar, Vismay; Andrews, Edward; Lang, Michael; Chitale, Ameet; Oppenlander, Mark E; Maulucci, Christopher M; Sharan, Ashwini D; Heller, Joshua; Harrop, James S; Jallo, Jack; Prasad, Srinivas

2014-04-01

Retrospective case series. To demonstrate the microbial trends of spinal surgical site infections in patients who had previously received crystallized vancomycin in the operative bed. Prior large, case control series demonstrate the significant decrease in surgical site infection with the administration of vancomycin in the wound bed. A single institution, electronic database search was conducted for all patients who underwent spinal surgery who had received prophylactic crystalline vancomycin powder in the wound bed. Patients with a prior history of wound infection, intrathecal pumps, or spinal stimulators were excluded. A total of 981 consecutive patients (494 males, 487 females; mean age, 59.4 yr; range, 16-95 yr) were identified from January 2011 to June 2013. The average dose of vancomycin powder was 1.13 g (range, 1-6 g). Sixty-six patients (6.71%) were diagnosed with a surgical site infection, of which 51 patients had positive wound cultures (5.2%). Of the 51 positive cultures, the most common organism was Staphylococcus aureus. The average dose of vancomycin was 1.3 g in the 38 cases where a gram-positive organism was cultured. A number of gram-negative infections were encountered such as Serratia marcescens, Enterobacter aerogenes, Bacteroides fragilis, Enterobacter cloacae, Citrobacter koseri, and Pseudomonas aeruginosa. The average dose of vancomycin was 1.2 g in 23 cases where a gram-negative infection was cultured. Fifteen of the 51 positive cultures (29.4%) were polymicrobial. Eight (53%) of these 15 polymicrobial cultures contained 3 or more distinct organisms. Prophylactic intraoperative vancomycin use in the wound bed in spinal surgery may increase the incidence of gram-negative or polymicrobial spinal infections. The use of intraoperative vancomycin may correlate with postoperative seromas, due to the high incidence of nonpositive cultures. Large, randomized, prospective trials are needed to demonstrate causation and dose-response relationship.

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

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

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.

Novel Ambler class A beta-lactamase LAP-1 and its association with the plasmid-mediated quinolone resistance determinant QnrS1.

PubMed

Poirel, Laurent; Cattoir, Vincent; Soares, Ana; Soussy, Claude-James; Nordmann, Patrice

2007-02-01

The plasmid-mediated quinolone resistance determinant QnrS1 was identified in non-clonally related Enterobacter cloacae isolates in association with a transferable narrow-spectrum beta-lactam resistance marker. Cloning experiments allowed the identification of a novel Ambler class A beta-lactamase, named LAP-1. It shares 62 and 61% amino acid identity with the most closely related beta-lactamases, TEM-1 and SHV-1, respectively. It has a narrow-spectrum hydrolysis of beta-lactams and is strongly inhibited by clavulanic acid and sulbactam and, to a lesser extent, by tazobactam. Association of the blaLAP-1 gene with the qnrS1 gene was identified in E. cloacae isolates from France and Vietnam. These genes were plasmid located and associated with similar insertion sequences but were not associated with sul1-type class 1 integrons, as opposed to the qnrA genes.

[Antimicrobial activity of fosfomycin under various conditions against standard strains, beta-lactam resistant strains, and multidrug efflux system mutants].

PubMed

Mikuniya, Takeshi; Hiraishi, Toru; Maebashi, Kazunori; Ida, Takashi; Takata, Toshihiko; Hikida, Muneo; Yamada, Sakuo; Gotoh, Naomasa; Nishino, Takeshi

2005-04-01

The purpose of this study was to evaluate the possible benefit of fosfomycin (FOM) as prophylactic antibiotic in terms of antimicrobial activity and the potential of inducibility of beta-lactamase, compared with cefazolin, cefotiam, cefmetazole, and piperacillin that are commonly used as perioperative agents. The in vitro activity of FOM against aerobic Gram-negative bacteria using Mueller-Hinton agar or nutrient agar supplemented with glucose-6-phosphate (G6P) as tested medium increased within a range from 2 to 256 times the activity in the medium without G6P. However, the susceptibility of Gram-positive bacteria to FOM remained largely unchanged with or without G6P. There was no aerobic- or anaerobic-bacteria which changed susceptibility against beta-lactam antibiotics under various tested medium conditions. FOM demonstrated strong bactericidal activity against Escherichia coli and Pseudomonas aeruginosa in a dose dependent manner, and decreased viable cell counts of Staphylococcus aureus. In the case of P. aeruginosa, transmission electron micrographs study revealed that numerous lysed cells were present 2 hours after treatment with FOM at four times the MIC. First and second generation cephalosporins induced AmpC-type beta-lactamase in a dose dependent manner among beta-lactamase inducible strains of P. aeruginosa and Enterobacter cloacae. On the other hand, inducible activity of FOM on beta-lactamase production was less than 1/25 to 1/65 compared with those of cephalosporins. In addition, FOM maintained strong antimicrobial activity for over then 20 years after marketing, because of the excellent stability against various types of beta-lactamase produced by plasmid-carrying bacteria and clinical isolates. FOM was not extruded by four types of efflux systems, such as MexAB-OprM, MexCD-OprJ, MexXY/ OprM and MexEF-OprN, however beta-lactam antibiotics were substrates of MexAB-OprM and MexCD-OprJ. In conclusion, FOM provides adequate coverage for both aerobic Gram

Pseudomonas aeruginosa in premise plumbing of large buildings.

PubMed

Bédard, Emilie; Prévost, Michèle; Déziel, Eric

2016-12-01

Pseudomonas aeruginosa is an opportunistic bacterial pathogen that is widely occurring in the environment and is recognized for its capacity to form or join biofilms. The present review consolidates current knowledge on P. aeruginosa ecology and its implication in healthcare facilities premise plumbing. The adaptability of P. aeruginosa and its capacity to integrate the biofilm from the faucet and the drain highlight the role premise plumbing devices can play in promoting growth and persistence. A meta-analysis of P. aeruginosa prevalence in faucets (manual and electronic) and drains reveals the large variation in device positivity reported and suggest the high variability in the sampling approach and context as the main reason for this variation. The effects of the operating conditions that prevail within water distribution systems (disinfection, temperature, and hydraulic regime) on the persistence of P. aeruginosa are summarized. As a result from the review, recommendations for proactive control measures of water contamination by P. aeruginosa are presented. A better understanding of the ecology of P. aeruginosa and key influencing factors in premise plumbing are essential to identify culprit areas and implement effective control measures. © 2016 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

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

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

Effects of patterned topography on biofilm formation

NASA Astrophysics Data System (ADS)

Vasudevan, Ravikumar

2011-12-01

Bacterial biofilms are a population of bacteria attached to each other and irreversibly to a surface, enclosed in a matrix of self-secreted polymers, among others polysaccharides, proteins, DNA. Biofilms cause persisting infections associated with implanted medical devices and hospital acquired (nosocomial) infections. Catheter-associated urinary tract infections (CAUTIs) are the most common type of nosocomial infections accounting for up to 40% of all hospital acquired infections. Several different strategies, including use of antibacterial agents and genetic cues, quorum sensing, have been adopted for inhibiting biofilm formation relevant to CAUTI surfaces. Each of these methods pertains to certain types of bacteria, processes and has shortcomings. Based on eukaryotic cell topography interaction studies and Ulva linza spore studies, topographical surfaces were suggested as a benign control method for biofilm formation. However, topographies tested so far have not included a systematic variation of size across basic topography shapes. In this study patterned topography was systematically varied in size and shape according to two approaches 1) confinement and 2) wetting. For the confinement approach, using scanning electron microscopy and confocal microscopy, orienting effects of tested topography based on staphylococcus aureus (s. aureus) (SH1000) and enterobacter cloacae (e. cloacae) (ATCC 700258) bacterial models were identified on features of up to 10 times the size of the bacterium. Psuedomonas aeruginosa (p. aeruginosa) (PAO1) did not show any orientational effects, under the test conditions. Another important factor in medical biofilms is the identification and quantification of phenotypic state which has not been discussed in the literature concerning bacteria topography characterizations. This was done based on antibiotic susceptibility evaluation and also based on gene expression analysis. Although orientational effects occur, phenotypically no difference

Microbiology and Injury Characteristics in Severe Open Tibia Fractures from Combat

DTIC Science & Technology

2012-01-01

cloacae 17 18.3 Klebsiella pneumoniae 13 14 Enterococcus faecium 13 14 Pseudomonas aeruginosa 13 14 Staphylococcus epidermidis 6 6.5 Infection cultures 57...baumannii 10 19.6 Staphylococcus epidermidis 10 19.6 Klebsiella pneumoniae 6 11.8 Enterococcus faecium 4 7.8 Burns et al. J Trauma Volume 72, Number 4 © 2012

Emergence and Spread of Epidemic Multidrug-Resistant Pseudomonas aeruginosa.

PubMed

Miyoshi-Akiyama, Tohru; Tada, Tatsuya; Ohmagari, Norio; Viet Hung, Nguyen; Tharavichitkul, Prasit; Pokhrel, Bharat Mani; Gniadkowski, Marek; Shimojima, Masahiro; Kirikae, Teruo

2017-12-01

Pseudomonas aeruginosa (P. aeruginosa) is one of the most common nosocomial pathogens worldwide. Although the emergence of multidrug-resistant (MDR) P. aeruginosa is a critical problem in medical practice, the key features involved in the emergence and spread of MDR P. aeruginosa remain unknown. This study utilized whole genome sequence (WGS) analyses to define the population structure of 185 P. aeruginosa clinical isolates from several countries. Of these 185 isolates, 136 were categorized into sequence type (ST) 235, one of the most common types worldwide. Phylogenetic analysis showed that these isolates fell within seven subclades. Each subclade harbors characteristic drug resistance genes and a characteristic genetic background confined to a geographic location, suggesting that clonal expansion following antibiotic exposure is the driving force in generating the population structure of MDR P. aeruginosa. WGS analyses also showed that the substitution rate was markedly higher in ST235 MDR P. aeruginosa than in other strains. Notably, almost all ST235 isolates harbor the specific type IV secretion system and very few or none harbor the CRISPR/CAS system. These findings may help explain the mechanism underlying the emergence and spread of ST235 P. aeruginosa as the predominant MDR lineage. © The Author(s) 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

An antimicrobial peptide from the skin secretions of the mountain chicken frog Leptodactylus fallax (Anura:Leptodactylidae).

PubMed

Rollins-Smith, Louise A; King, Jay D; Nielsen, Per F; Sonnevend, Agnes; Conlon, J Michael

2005-01-15

A 25 amino-acid-residue, C-terminally alpha-amidated peptide with antimicrobial activity, which has been termed fallaxin, was isolated in high yield from the norepinephrine-stimulated skin secretions of the mountain chicken frog Leptodactylus fallax (Anura:Leptodactylidae). The amino acid sequence of the peptide (Gly-Val-Val-Asp-Ile-Leu-Lys-Gly-Ala-Ala-Lys-Asp-Ile-Ala-Gly-His-Leu-Ala-Ser-Lys-Val-Met-Asn-Lys-Leu.NH2) shows structural similarity with members of the ranatuerin-2 family previously isolated from the skins of frogs of the genus Rana that are only distantly related to the Leptodactylidae. This observation is consistent with the hypothesis that many frog skin antimicrobial peptides are related evolutionarily, having arisen from multiple duplications of an ancestral gene that existed before the radiation of the different families. Fallaxin inhibited the growth of reference strains of Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Enterobacter cloacae, Klebsiella pneumoniae) but with relatively low potency (MIC> or =20 microM) and was inactive against the Gram-positive bacterium (Staphylococcus aureus) and the yeast Candida albicans. The hemolytic activity of fallaxin was very low (HC50>200 microM). A second peptide, comprising residues (1-22) of fallaxin, was also isolated from the skin secretions but this component was inactive against the microorganisms tested.

[Antibibiotic resistance by nosocomial infections' causal agents].

PubMed

Salazar-Holguín, Héctor Daniel; Cisneros-Robledo, María Elena

2016-01-01

The antibibiotic resistance by nosocomial infections (NI) causal agents constitutes a seriously global problematic that involves the Mexican Institute of Social Security's Regional General Hospital 1 in Chihuahua, Mexico; although with special features that required to be specified and evaluated, in order to concrete an effective therapy. Observational, descriptive and prospective study; by means of active vigilance all along 2014 in order to detect the nosocomial infections, for epidemiologic study, culture and antibiogram to identify its causal agents and antibiotics resistance and sensitivity. Among 13527 hospital discharges, 1079 displayed NI (8 %), standed out: the related on vascular lines, of surgical site, pneumonia and urinal track; they added up two thirds of the total. We carried out culture and antibiogram about 300 of them (27.8 %); identifying 31 bacterian species, mainly seven of those (77.9 %): Escherichia coli, Staphylococcus aureus and epidermidis, Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae and Enterobacter cloacae; showing multiresistance to 34 tested antibiotics, except in seven with low or without resistance at all: vancomycin, teicoplanin, linezolid, quinupristin-dalfopristin, piperacilin-tazobactam, amikacin and carbapenems. When we contrasted those results with the recommendations in the clinical practice guides, it aroused several contradictions; so they must be taken with reserves and has to be tested in each hospital, by means of cultures and antibiograms in practically every case of nosocomial infection.

In Vitro Assessment of the Antimicrobial Efficacy of Optimized Nitroglycerin-Citrate-Ethanol as a Nonantibiotic, Antimicrobial Catheter Lock Solution for Prevention of Central Line-Associated Bloodstream Infections

PubMed Central

Reitzel, Ruth A.; Hirsh-Ginsberg, Cheryl; Murray, Kimberly; Chaftari, Anne-Marie; Hachem, Ray; Raad, Issam

2016-01-01

The rapid, broad-spectrum, biofilm-eradicating activity of the combination of 0.01% nitroglycerin, 7% citrate, and 20% ethanol and its potential as a nonantibiotic, antimicrobial catheter lock solution (ACLS) were previously reported. Here, a nitroglycerin-citrate-ethanol (NiCE) ACLS optimized for clinical assessment was developed by reducing the nitroglycerin and citrate concentrations and increasing the ethanol concentration. Biofilm-eradicating activity was sustained when the ethanol concentration was increased from 20 to 22% which fully compensated for reducing the citrate concentration from 7% to 4% as well as the nitroglycerin concentration from 0.01% to 0.0015% or 0.003%. The optimized formulations demonstrated complete and rapid (2 h) eradication of methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-intermediate Staphylococcus aureus (VISA), methicillin-resistant Staphylococcus epidermidis (MRSE), vancomycin-resistant enterococci (VRE), multidrug-resistant (MDR) Pseudomonas aeruginosa, MDR Klebsiella pneumoniae, MDR Enterobacter cloacae, MDR Acinetobacter baumannii, MDR Escherichia coli, MDR Stenotrophomonas maltophilia, Candida albicans, and Candida glabrata biofilms. The optimized NiCE lock solutions demonstrated anticoagulant activities comparable to those of heparin lock solutions. NiCE lock solution was significantly more effective than taurolidine-citrate-heparin lock solution in eradicating biofilms of Staphylococcus aureus and Candida glabrata. The optimized, nonantibiotic, heparin-free NiCE lock solution demonstrates rapid broad-spectrum biofilm eradication as well as effective anticoagulant activity, making NiCE a high-quality ACLS candidate for clinical assessment. PMID:27297475

Pseudomonas aeruginosa Promotes Escherichia coli Biofilm Formation in Nutrient-Limited Medium

PubMed Central

Culotti, Alessandro; Packman, Aaron I.

2014-01-01

Biofilms have been implicated as an important reservoir for pathogens and commensal enteric bacteria such as Escherichia coli in natural and engineered water systems. However, the processes that regulate the survival of E. coli in aquatic biofilms have not been thoroughly studied. We examined the effects of hydrodynamic shear and nutrient concentrations on E. coli colonization of pre-established Pseudomonas aeruginosa biofilms, co-inoculation of E. coli and P. aeruginosa biofilms, and P. aeruginosa colonization of pre-established E. coli biofilms. In nutritionally-limited R2A medium, E. coli dominated biofilms when co-inoculated with P. aeruginosa, and successfully colonized and overgrew pre-established P. aeruginosa biofilms. In more enriched media, P. aeruginosa formed larger clusters, but E. coli still extensively overgrew and colonized the interior of P. aeruginosa clusters. In mono-culture, E. coli formed sparse and discontinuous biofilms. After P. aeruginosa was introduced to these biofilms, E. coli growth increased substantially, resulting in patterns of biofilm colonization similar to those observed under other sequences of organism introduction, i.e., E. coli overgrew P. aeruginosa and colonized the interior of P. aeruginosa clusters. These results demonstrate that E. coli not only persists in aquatic biofilms under depleted nutritional conditions, but interactions with P. aeruginosa can greatly increase E. coli growth in biofilms under these experimental conditions. PMID:25198725

Effect of Hydrazines on Substrate Utilization by a Strain of Enterobacter Cloacae

DTIC Science & Technology

1983-01-01

UDMH) to a strain of soil bacteria to be comparable to that observed in other biological systems. A subsequent study by MANTEL & LONDON (1980) suggested...metabolites derived from lysed cells were being metabolized . This observation in conjunction with reports on the effects of Hz intoxication on...carbohydrate metabolism (UNDERHILL & HOGAN 1915, IZUME & LEWIS 1926-1927, SMITH 1965, TAYLOR 1966, GEORGE & BACK 1977) prompted an investigation of the effects

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.

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.

[Effect of Pseudomonas aeruginosa melanin on antibiotic activity].

PubMed

Rozhavin, M A

1978-08-01

The properties of microbial melanines are very diverse. Melanine of P. aeruginosa is little studied. The pigment was isolated from a strain of P. aeruginosa possessing all characteristic properties of the species. Interaction of P. aeruginosa melanine with various antibiotics was determined by the method of serial dilutions in beaf-peptone broth, using Staph. aureus 209 as a test-microbe, which was added to the medium in an amount of 10(6) cells to each tube. It was found that P. aeruginosa melanine differed from DOPA-melanine in a concentration of 1 mg/ml and did not change the activity of penicillin, tetracycline, oleandomycin, kanamycin and gentamicin with respect to Staph. aureus.

Indomethacin-associated neutropenia with subsequent Gram-negative sepsis in a preterm infant. Cause or coincidence?

PubMed

Bengtsson, B-O S; Milstein, J M; Sherman, M P

2006-06-01

A preterm male infant with a patent ductus arteriosus developed neutropenia during treatment with indomethacin. Afterward, the mother described her own history of indomethacin-associated neutropenia. During the recovery from the neutropenia, the infant became septic with bacteremia caused by Enterobacter cloacae. Although indomethacin-related neutropenia has been described in adults, no case in a neonate has been reported. If neutropenia occurs after indomethacin therapy in a neonate, a familial history of indomethacin-associated neutropenia should be sought and the increased risk of infection should be considered.

First Report of German Cockroaches (Blattella germanica) as Reservoirs of CTX-M-15 Extended-Spectrum-β-Lactamase- and OXA-48 Carbapenemase-Producing Enterobacteriaceae in Batna University Hospital, Algeria

PubMed Central

Loucif, Lotfi; Gacemi-Kirane, Djamila; Cherak, Zineb; Chamlal, Naima; Grainat, Nadia

2016-01-01

Here we report the isolation of extended-spectrum β-lactamase (ESBL)- and carbapenemase-producing Enterobacteriaceae from German cockroaches caught in the burn unit of Batna University Hospital in Algeria. Nine of 12 isolates harbored the blaCTX-M-15 ESBL gene. One Enterobacter cloacae isolate belonging to sequence type 528 coexpressed the blaOXA-48, blaCTX-M-15, and blaTEM genes. Our findings indicate that cockroaches may be one of the most dangerous reservoirs for ESBL and carbapenemase producers in hospitals. PMID:27458214

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.

Risk assessment of Pseudomonas aeruginosa in water.

PubMed

Mena, Kristina D; Gerba, Charles P

2009-01-01

P. aeruginosa is part of a large group of free-living bacteria that are ubiquitous in the environment. This organism is often found in natural waters such as lakes and rivers in concentrations of 10/100 mL to >1,000/100 mL. However, it is not often found in drinking water. Usually it is found in 2% of samples, or less, and at concentrations up to 2,300 mL(-1) (Allen and Geldreich 1975) or more often at 3-4 CFU/mL. Its occurrence in drinking water is probably related more to its ability to colonize biofilms in plumbing fixtures (i.e., faucets, showerheads, etc.) than its presence in the distribution system or treated drinking water. P. aeruginosa can survive in deionized or distilled water (van der Jooij et al. 1982; Warburton et al. 1994). Hence, it may be found in low nutrient or oligotrophic environments, as well as in high nutrient environments such as in sewage and in the human body. P. aeruginosa can cause a wide range of infections, and is a leading cause of illness in immunocompromised individuals. In particular, it can be a serious pathogen in hospitals (Dembry et al. 1998). It can cause endocarditis, osteomyelitis, pneumonia, urinary tract infections, gastrointestinal infections, and meningitis, and is a leading cause of septicemia. P. aeruginosa is also a major cause of folliculitis and ear infections acquired by exposure to recreational waters containing the bacterium. In addition, it has been recognized as a serious cause of keratitis, especially in patients wearing contact lenses. P. aeruginosa is also a major pathogen in burn and cystic fibrosis (CF) patients and causes a high mortality rate in both populations (MOlina et al. 1991; Pollack 1995). P. aeruginosa is frequently found in whirlpools and hot tubs, sometimes in 94-100% of those tested at concenrations of <1 to 2,400 CFU/mL. The high concentrations found probably result from the relatively high temperatures of whirlpools, which favor the growth of P. aeruginosa, and the aeration which also

Pseudomonas aeruginosa inhibits the growth of Cryptococcus species.

PubMed

Rella, Antonella; Yang, Mo Wei; Gruber, Jordon; Montagna, Maria Teresa; Luberto, Chiara; Zhang, Yong-Mei; Del Poeta, Maurizio

2012-06-01

Pseudomonas aeruginosa is a ubiquitous and opportunistic bacterium that inhibits the growth of different microorganisms, including Gram-positive bacteria and fungi such as Candida spp. and Aspergillus fumigatus. In this study, we investigated the interaction between P. aeruginosa and Cryptococcus spp. We found that P. aeruginosa PA14 and, to a lesser extent, PAO1 significantly inhibited the growth of Cryptococcus spp. The inhibition of growth was observed on solid medium by the visualization of a zone of inhibition of yeast growth and in liquid culture by viable cell counting. Interestingly, such inhibition was only observed when P. aeruginosa and Cryptococcus were co-cultured. Minimal inhibition was observed when cell-cell contact was prevented using a separation membrane, suggesting that cell contact is required for inhibition. Using mutant strains of Pseudomonas quinoline signaling, we showed that P. aeruginosa inhibited the growth of Cryptococcus spp. by producing antifungal molecules pyocyanin, a redox-active phenazine, and 2-heptyl-3,4-dihydroxyquinoline (PQS), an extracellular quorum-sensing signal. Because both P. aeruginosa and Cryptococcus neoformans are commonly found in lung infections of immunocompromised patients, this study may have important implication for the interaction of these microbes in both an ecological and a clinical point of view.

Introduction of Pseudomonas aeruginosa into a Hospital via Vegetables

PubMed Central

Kominos, Spyros D.; Copeland, Charles E.; Grosiak, Barbara; Postic, Bosko

1972-01-01

Pseudomonas aeruginosa was isolated from tomatoes, radishes, celery, carrots, endive, cabbage, cucumbers, onions, and lettuce obtained from the kitchen of a general hospital, with tomatoes yielding both highest frequencies of isolation and highest counts. Presence of P. aeruginosa on the hands of kitchen personnel and cutting boards and knives which they used suggests acquisition of the organism through contact with these vegetables. It is estimated that a patient consuming an average portion of tomato salad might ingest as many as 5 × 103 colony-forming units of P. aeruginosa. Pyocine types of P. aeruginosa isolated from clinical specimens were frequently identical to those recovered from vegetables, thus implicating tomatoes and other vegetables as an important source and vehicle by which P. aeruginosa colonizes the intestinal tract of patients. PMID:4628795

In Vitro Activity of Imipenem-Relebactam against Gram-Negative ESKAPE Pathogens Isolated by Clinical Laboratories in the United States in 2015 (Results from the SMART Global Surveillance Program).

PubMed

Lob, Sibylle H; Hackel, Meredith A; Kazmierczak, Krystyna M; Young, Katherine; Motyl, Mary R; Karlowsky, James A; Sahm, Daniel F

2017-06-01

Relebactam (formerly MK-7655) is an inhibitor of class A and C β-lactamases, including Klebsiella pneumoniae carbapenemase (KPC), and is currently in clinical development in combination with imipenem-cilastatin. Using Clinical and Laboratory Standards Institute (CLSI)-defined broth microdilution methodology, we evaluated the in vitro activities of imipenem-relebactam, imipenem, and seven routinely tested parenteral antimicrobial agents against Gram-negative ESKAPE pathogens (including Klebsiella pneumoniae , n = 689; Acinetobacter baumannii , n = 72; Pseudomonas aeruginosa , n = 845; and Enterobacter spp., n = 399) submitted by 21 clinical laboratories in the United States in 2015 as part of the SMART (Study for Monitoring Antimicrobial Resistance Trends) global surveillance program. Relebactam was tested at a fixed concentration of 4 μg/ml in combination with doubling dilutions of imipenem. Imipenem-relebactam MICs were interpreted using CLSI imipenem breakpoints. The respective rates of susceptibility to imipenem-relebactam and imipenem were 94.2% (796/845) and 70.3% (594/845) for P. aeruginosa , 99.0% (682/689) and 96.1% (662/689) for K. pneumoniae , and 100% (399/399) and 98.0% (391/399) for Enterobacter spp. Relebactam restored imipenem susceptibility to 80.5% (202/251), 74.1% (20/27), and 100% (8/8) of isolates of imipenem-nonsusceptible P. aeruginosa , K. pneumoniae , and Enterobacter spp. Relebactam did not increase the number of isolates of Acinetobacter spp. susceptible to imipenem, and the rates of resistance to all of the agents tested against this pathogen were >30%. Further development of imipenem-relebactam is warranted given the demonstrated ability of relebactam to restore the activity of imipenem against current clinical isolates of Enterobacteriaceae and P. aeruginosa that are nonsusceptible to carbapenems and its potential as a therapy for treating patients with antimicrobial-resistant Gram-negative infections. Copyright © 2017 American

In Vitro Activity of Imipenem-Relebactam against Gram-Negative ESKAPE Pathogens Isolated by Clinical Laboratories in the United States in 2015 (Results from the SMART Global Surveillance Program)

PubMed Central

Hackel, Meredith A.; Kazmierczak, Krystyna M.; Young, Katherine; Motyl, Mary R.; Karlowsky, James A.; Sahm, Daniel F.

2017-01-01

ABSTRACT Relebactam (formerly MK-7655) is an inhibitor of class A and C β-lactamases, including Klebsiella pneumoniae carbapenemase (KPC), and is currently in clinical development in combination with imipenem-cilastatin. Using Clinical and Laboratory Standards Institute (CLSI)-defined broth microdilution methodology, we evaluated the in vitro activities of imipenem-relebactam, imipenem, and seven routinely tested parenteral antimicrobial agents against Gram-negative ESKAPE pathogens (including Klebsiella pneumoniae, n = 689; Acinetobacter baumannii, n = 72; Pseudomonas aeruginosa, n = 845; and Enterobacter spp., n = 399) submitted by 21 clinical laboratories in the United States in 2015 as part of the SMART (Study for Monitoring Antimicrobial Resistance Trends) global surveillance program. Relebactam was tested at a fixed concentration of 4 μg/ml in combination with doubling dilutions of imipenem. Imipenem-relebactam MICs were interpreted using CLSI imipenem breakpoints. The respective rates of susceptibility to imipenem-relebactam and imipenem were 94.2% (796/845) and 70.3% (594/845) for P. aeruginosa, 99.0% (682/689) and 96.1% (662/689) for K. pneumoniae, and 100% (399/399) and 98.0% (391/399) for Enterobacter spp. Relebactam restored imipenem susceptibility to 80.5% (202/251), 74.1% (20/27), and 100% (8/8) of isolates of imipenem-nonsusceptible P. aeruginosa, K. pneumoniae, and Enterobacter spp. Relebactam did not increase the number of isolates of Acinetobacter spp. susceptible to imipenem, and the rates of resistance to all of the agents tested against this pathogen were >30%. Further development of imipenem-relebactam is warranted given the demonstrated ability of relebactam to restore the activity of imipenem against current clinical isolates of Enterobacteriaceae and P. aeruginosa that are nonsusceptible to carbapenems and its potential as a therapy for treating patients with antimicrobial-resistant Gram-negative infections. PMID:28320716

Pseudomonas aeruginosa essentials: an update on investigation of essential genes.

PubMed

Juhas, Mario

2015-11-01

Pseudomonas aeruginosa is the leading cause of nosocomial infections, particularly in immunocompromised, cancer, burn and cystic fibrosis patients. Development of novel antimicrobials against P. aeruginosa is therefore of the highest importance. Although the first reports on P. aeruginosa essential genes date back to the early 2000s, a number of more sensitive genomic approaches have been used recently to better define essential genes in this organism. These analyses highlight the evolution of the definition of an 'essential' gene from the traditional to the context-dependent. Essential genes, particularly those indispensable under the clinically relevant conditions, are considered to be promising targets of novel antibiotics against P. aeruginosa. This review provides an update on the investigation of P. aeruginosa essential genes. Special focus is on recently identified P. aeruginosa essential genes and their exploitation for the development of antimicrobials.

Pseudomonas aeruginosa facilitates Campylobacter jejuni growth in biofilms under oxic flow conditions.

PubMed

Culotti, Alessandro; Packman, Aaron I

2015-12-01

We investigated the growth of Campylobacter jejuni in biofilms with Pseudomonas aeruginosa under oxic flow conditions. We observed the growth of C. jejuni in mono-culture, deposited on pre-established P. aeruginosa biofilms, and co-inoculated with P. aeruginosa. In mono-culture, C. jejuni was unable to form biofilms. However, deposited C. jejuni continuously grew on pre-established P. aeruginosa biofilms for a period of 3 days. The growth of scattered C. jejuni clusters was strictly limited to the P. aeruginosa biofilm surface, and no intergrowth was observed. Co-culturing of C. jejuni and P. aeruginosa also enabled the growth of both organisms in biofilms, with C. jejuni clusters developing on the surface of the P. aeruginosa biofilm. Dissolved oxygen (DO) measurements in the medium showed that P. aeruginosa biofilms depleted the effluent DO from 9.0 to 0.5 mg L(-1) 24 hours after inoculation. The localized microaerophilic environment generated by P. aeruginosa promoted the persistence and growth of C. jejuni. Our findings show that P. aeruginosa not only prolongs the survival of C. jejuni under oxic conditions, but also enables the growth of C. jejuni on the surface of P. aeruginosa biofilms. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Feasibility of biohydrogen production from industrial wastes using defined microbial co-culture.

PubMed

Chen, Peng; Wang, Yuxia; Yan, Lei; Wang, Yiqing; Li, Suyue; Yan, Xiaojuan; Wang, Ningbo; Liang, Ning; Li, Hongyu

2015-05-06

The development of clean or novel alternative energy has become a global trend that will shape the future of energy. In the present study, 3 microbial strains with different oxygen requirements, including Clostridium acetobutylicum ATCC 824, Enterobacter cloacae ATCC 13047 and Kluyveromyces marxianus 15D, were used to construct a hydrogen production system that was composed of a mixed aerobic-facultative anaerobic-anaerobic consortium. The effects of metal ions, organic acids and carbohydrate substrates on this system were analyzed and compared using electrochemical and kinetic assays. It was then tested using small-scale experiments to evaluate its ability to convert starch in 5 L of organic wastewater into hydrogen. For the one-step biohydrogen production experiment, H1 medium (nutrient broth and potato dextrose broth) was mixed directly with GAM broth to generate H2 medium (H1 medium and GAM broth). Finally, Clostridium acetobutylicum ATCC 824, Enterobacter cloacae ATCC 13047 and Kluyveromyces marxianus 15D of three species microbial co-culture to produce hydrogen under anaerobic conditions. For the two-step biohydrogen production experiment, the H1 medium, after cultured the microbial strains Enterobacter cloacae ATCC 13047 and Kluyveromyces marxianus 15D, was centrifuged to remove the microbial cells and then mixed with GAM broth (H2 medium). Afterward, the bacterial strain Clostridium acetobutylicum ATCC 824 was inoculated into the H2 medium to produce hydrogen by anaerobic fermentation. The experimental results demonstrated that the optimum conditions for the small-scale fermentative hydrogen production system were at pH 7.0, 35°C, a mixed medium, including H1 medium and H2 medium with 0.50 mol/L ferrous chloride, 0.50 mol/L magnesium sulfate, 0.50 mol/L potassium chloride, 1% w/v citric acid, 5% w/v fructose and 5% w/v glucose. The overall hydrogen production efficiency in the shake flask fermentation group was 33.7 mL/h(-1).L(-1), and those the two

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...

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.

Pseudomonas aeruginosa infections of intact skin.

PubMed

Agger, W A; Mardan, A

1995-02-01

Pseudomonas aeruginosa infections of healthy skin are uncommon. We report four cases of P. aeruginosa infections of intact skin. These cases illustrate the clinical spectrum of these cutaneous infections: localized, mild epidermal infections (the green nail syndrome and webbed space infections), moderately serious infections (cutaneous folliculitis and otitis externa), and, in immunocompromised patients, extremely serious infections (malignant otitis externa, perirectal infection, and ecthyma gangrenosum).

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.

Gallium-Protoporphyrin IX Inhibits Pseudomonas aeruginosa Growth by Targeting Cytochromes.

PubMed

Hijazi, Sarah; Visca, Paolo; Frangipani, Emanuela

2017-01-01

Pseudomonas aeruginosa is a challenging pathogen due to both innate and acquired resistance to antibiotics. It is capable of causing a variety of infections, including chronic lung infection in cystic fibrosis (CF) patients. Given the importance of iron in bacterial physiology and pathogenicity, iron-uptake and metabolism have become attractive targets for the development of new antibacterial compounds. P. aeruginosa can acquire iron from a variety of sources to fulfill its nutritional requirements both in the environment and in the infected host. The adaptation of P. aeruginosa to heme iron acquisition in the CF lung makes heme utilization pathways a promising target for the development of new anti- Pseudomonas drugs. Gallium [Ga(III)] is an iron mimetic metal which inhibits P. aeruginosa growth by interfering with iron-dependent metabolism. The Ga(III) complex of the heme precursor protoporphyrin IX (GaPPIX) showed enhanced antibacterial activity against several bacterial species, although no inhibitory effect has been reported on P. aeruginosa . Here, we demonstrate that GaPPIX is indeed capable of inhibiting the growth of clinical P. aeruginosa strains under iron-deplete conditions, as those encountered by bacteria during infection, and that GaPPIX inhibition is reversed by iron. Using P. aeruginosa PAO1 as model organism, we show that GaPPIX enters cells through both the heme-uptake systems has and phu , primarily via the PhuR receptor which plays a crucial role in P. aeruginosa adaptation to the CF lung. We also demonstrate that intracellular GaPPIX inhibits the aerobic growth of P. aeruginosa by targeting cytochromes, thus interfering with cellular respiration.

Detection of Metallo-Beta Lactamases Among Carbapenem-Resistant Pseudomonas aeruginosa.

PubMed

Farajzadeh Sheikh, Ahmad; Rostami, Soodabeh; Jolodar, Abbas; Tabatabaiefar, Mohammad Amin; Khorvash, Farzin; Saki, Azadeh; Shoja, Saeed; Sheikhi, Raheleh

2014-11-01

Carbapenems are important drugs used for the treatment of Pseudomonas aeruginosa infections, however metallo-β-lactamases (MBL) are able to efficiently hydrolyze these classes of drugs. Immediate detection of the MBL-producing P. aeruginosa is necessary in order to accurately treat infections caused by this organism. To determine the prevalence of MBL producing P. aeruginosa in burn and non-burn patients by two phenotypic tests and polymerase chain reaction (PCR) and to compare phenotypic tests with PCR. A total of 223 non-duplicate strains of P. aeruginosa were collected from three teaching hospitals of Ahvaz, Iran. Antimicrobial susceptibility and minimum inhibitory concentrations (MICs) of carbapenems (imipenem, meropenem, doripenem and ertapenem) were determined by the Kirby-Bauer and E-test methods. Combined disk (CD) test, MBL E-test and PCR were performed for carbapenem-resistant P. aeruginosa isolates. Amongst all the P. aeruginosa isolates, 58.7% were resistant to imipenem while 31.8%, 13.5% and 74.4% were resistant to meropenem, doripenem and ertapenem, respectively. Amongst all the P. aeruginosa isolates, 44.4% were multidrug resistant and 13.45% were resistant to all of the carbapenems. The CD test with doripenem disk / 750 μg ethylene diamine tetra acetic acid (EDTA) had the highest efficiency compared to the other phenotypic tests. bla IMP and bla VIM genes were detected in 11.7% and 0.4% of isolates, respectively. bla SPM and bla NDM genes were not observed. Epidemiological and regional evaluation of MBL-producing P. aeruginosa through simple and inexpensive methods should be considered for effective treatment of carbapenem-resistant P. aeruginosa infections.

Mechanisms of phagocytosis and host clearance of Pseudomonas aeruginosa

PubMed Central

Lovewell, Rustin R.; Patankar, Yash R.

2014-01-01

Pseudomonas aeruginosa is an opportunistic bacterial pathogen responsible for a high incidence of acute and chronic pulmonary infection. These infections are particularly prevalent in patients with chronic obstructive pulmonary disease and cystic fibrosis: much of the morbidity and pathophysiology associated with these diseases is due to a hypersusceptibility to bacterial infection. Innate immunity, primarily through inflammatory cytokine production, cellular recruitment, and phagocytic clearance by neutrophils and macrophages, is the key to endogenous control of P. aeruginosa infection. In this review, we highlight recent advances toward understanding the innate immune response to P. aeruginosa, with a focus on the role of phagocytes in control of P. aeruginosa infection. Specifically, we summarize the cellular and molecular mechanisms of phagocytic recognition and uptake of P. aeruginosa, and how current animal models of P. aeruginosa infection reflect clinical observations in the context of phagocytic clearance of the bacteria. Several notable phenotypic changes to the bacteria are consistently observed during chronic pulmonary infections, including changes to mucoidy and flagellar motility, that likely enable or reflect their ability to persist. These traits are likewise examined in the context of how the bacteria avoid phagocytic clearance, inflammation, and sterilizing immunity. PMID:24464809

Mechanisms of phagocytosis and host clearance of Pseudomonas aeruginosa.

PubMed

Lovewell, Rustin R; Patankar, Yash R; Berwin, Brent

2014-04-01

Pseudomonas aeruginosa is an opportunistic bacterial pathogen responsible for a high incidence of acute and chronic pulmonary infection. These infections are particularly prevalent in patients with chronic obstructive pulmonary disease and cystic fibrosis: much of the morbidity and pathophysiology associated with these diseases is due to a hypersusceptibility to bacterial infection. Innate immunity, primarily through inflammatory cytokine production, cellular recruitment, and phagocytic clearance by neutrophils and macrophages, is the key to endogenous control of P. aeruginosa infection. In this review, we highlight recent advances toward understanding the innate immune response to P. aeruginosa, with a focus on the role of phagocytes in control of P. aeruginosa infection. Specifically, we summarize the cellular and molecular mechanisms of phagocytic recognition and uptake of P. aeruginosa, and how current animal models of P. aeruginosa infection reflect clinical observations in the context of phagocytic clearance of the bacteria. Several notable phenotypic changes to the bacteria are consistently observed during chronic pulmonary infections, including changes to mucoidy and flagellar motility, that likely enable or reflect their ability to persist. These traits are likewise examined in the context of how the bacteria avoid phagocytic clearance, inflammation, and sterilizing immunity.

Increased cefepime MIC for enterobacteriacae clinical isolates.

PubMed

Najafi, Narges; Alikhani, Ahmad; Babamahmoudi, Farhang; Davoudi, Alireza; Ghasemiyan, Roya; Aliyan, Shahriar; Shoujaiifar, Arman

2013-01-01

Background : Cefepime was used as empirical treatment in ventilator-associated pneumonia (VAP) induced by gram-negative and gram-positive bacteria. This study aimed to determine the antimicrobial susceptibility pattern of cefepime against microorganism causing VAP in Mazandaran, North of Iran. This study was performed on VAP patients diagnosed with clinical pulmonary infection score (CPIS) scores in ICU of two hospitals. For each patient suspected of having VAP, quantitative culture of endotracheal aspiration (QEA) was performed and MIC was determined by micro dilution test. Data were collected and analyzed. Thirty- five cases of enterobacteriaceae were isolated orderly including E coli 13, P. aeruginosa 11, Enterobacter 7 and K. pneumonia 4 cases. All the isolated E. coli, Enterobacter and Klebsiella, 54.5% of P. aeruginosa isolated were fully resistant to cefepime. The results of this study show that cefepime is not a reasonable choice for empirical treatment of nosocomial pneumonia and VAP.

Single-cell protein from methanol with Enterobacter aerogenes

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

Gnan, S.O.; Abodreheba, A.O.

1987-02-20

An identified Enterobacter aerogenes utilizing methanol as a sole carbon source was studied for the optimization of biomass production and the reduction of its nucleic acid content. Results indicated that the highest yield and conversion were obtained at 0.5% methanol. The addition of seawater as a source of trace elements has an adverse effect. However, the addition of urea as source of nitrogen enhanced the growth of E. aerogenes. Heat shock at 60 degrees C for one minute followed by incubation at 50 degrees C for 2 hours caused 72.6% reduction in the nucleic acid. 12 references.

Comparison of UVB and UVC irradiation disinfection efficacies on Pseudomonas Aeruginosa (P. aeruginosa) biofilm

NASA Astrophysics Data System (ADS)

Argyraki, A.; Markvart, M.; Nielsen, Anne; Bjarnsholt, T.; Bjørndal, L.; Petersen, P. M.

2016-04-01

Disinfection routines are important in all clinical applications. The uprising problem of antibiotic resistance has driven major research efforts towards alternative disinfection approaches, involving light-based solutions. Pseudomonas aeruginosa (P. aeruginosa) is a common bacterium that can cause skin, soft tissue, lungs, kidney and urinary tract infections. Moreover, it can be found on and in medical equipment causing often cross infections in hospitals. The objective of this study was to test the efficiency, of two different light-based disinfection treatments, namely UVB and UVC irradiation, on P. aeruginosa biofilms at different growth stages. In our experiments a new type of UV light emitting diodes (LEDs) were used to deliver UV irradiation on the biofilms, in the UVB (296nm) and UVC (266nm) region. The killing rate was studied as a function of dose for 24h grown biofilms. The dose was ramped from 72J/m2 to 10000J/m2. It was shown that UVB irradiation was more effective than UVC irradiation in inactivating P. aeruginosa biofilms. No colony forming units (CFU) were observed for the UVB treated biofilms when the dose was 10000 J/m2 (CFU in control sample: 7.5 x 104). UVB irradiation at a dose of 20000J/m2 on mature biofilms (72h grown) resulted in a 3.9 log killing efficacy. The fact that the wavelength of 296nm exists in daylight and has such disinfection ability on biofilms gives new perspectives for applications within disinfection at hospitals.

T lymphocyte-mediated protection against Pseudomonas aeruginosa infection in granulocytopenic mice.

PubMed Central

Powderly, W G; Pier, G B; Markham, R B

1986-01-01

BALB/c mice immunized with Pseudomonas aeruginosa immunotype 1 polysaccharide develop protective T cell immunity to bacterial challenge. In vitro, T cells from immunized mice kill P. aeruginosa by production of a bactericidal lymphokine. The present study demonstrates that adoptive transfer of T cells from immunized BALB/c mice to granulocytopenic mice resulted in 97% survival on challenge with P. aeruginosa, compared with 17% survival with adoptive transfer of T cells from nonimmune BALB/c mice. This protection is specifically elicited by reexposure to the original immunizing antigen; adoptive recipients cannot withstand challenge with immunotype 3 P. aeruginosa. However, the adoptive recipients do survive simultaneous infection with both P. aeruginosa immunotypes 1 and 3. Adoptive transfer of T cells from the congenic CB.20 mice, which are unable to kill P. aeruginosa in vitro, provides only 20% protection to granulocytopenic mice. These studies indicate that transfer of specific immune T lymphocytes can significantly enhance the resistance to P. aeruginosa infection in granulocytopenic mice. PMID:2426306

Unusual association of NDM-1 with KPC-2 and armA among Brazilian Enterobacteriaceae isolates

PubMed Central

Quiles, M.G.; Rocchetti, T.T.; Fehlberg, L.C.; Kusano, E.J.U.; Chebabo, A.; Pereira, R.M.G.; Gales, A.C.; Pignatari, A.C.C.

2014-01-01

We report the microbiological characterization of four New Delhi metallo-β-lactamase-1 (bla NDM-1)-producing Enterobacteriaceae isolated in Rio de Janeiro, Brazil. bla NDM-1 was located on a conjugative plasmid and was associated with Klebsiella pneumoniae carbapenemase-2 (bla KPC-2) or aminoglycoside-resistance methylase (armA), a 16S rRNA methylase not previously reported in Brazil, in two distinct strains of Enterobacter cloacae. Our results suggested that the introduction of bla NDM-1 in Brazil has been accompanied by rapid spread, since our isolates showed no genetic relationship. PMID:25466163

Current therapies for pseudomonas aeruginosa.

PubMed

Giamarellou, Helen; Kanellakopoulou, Kyriaki

2008-04-01

Based on the worldwide prevalence of multidrug-resistant strains of Pseudomas aeruginosa and the fact that no newer antipseudomonal agents are available, this article aims to investigate therapeutic solutions for combating infections caused by P aeruginosa, including multidrug-resistant strains. The article focuses mainly on colistin, the re-emerging old antibiotic that possesses prominent antipseudomonal activity in vitro and on doripenem, a newer carbapenem that seems to be close to its global marketing. Regarding older antipseudomonal antibiotics that have been reviewed extensively, only newer aspects on their use are considered in this article.

Dissecting the machinery that introduces disulfide bonds in Pseudomonas aeruginosa.

PubMed

Arts, Isabelle S; Ball, Geneviève; Leverrier, Pauline; Garvis, Steven; Nicolaes, Valérie; Vertommen, Didier; Ize, Bérengère; Tamu Dufe, Veronica; Messens, Joris; Voulhoux, Romé; Collet, Jean-François

2013-12-10

Disulfide bond formation is required for the folding of many bacterial virulence factors. However, whereas the Escherichia coli disulfide bond-forming system is well characterized, not much is known on the pathways that oxidatively fold proteins in pathogenic bacteria. Here, we report the detailed unraveling of the pathway that introduces disulfide bonds in the periplasm of the human pathogen Pseudomonas aeruginosa. The genome of P. aeruginosa uniquely encodes two DsbA proteins (P. aeruginosa DsbA1 [PaDsbA1] and PaDsbA2) and two DsbB proteins (PaDsbB1 and PaDsbB2). We found that PaDsbA1, the primary donor of disulfide bonds to secreted proteins, is maintained oxidized in vivo by both PaDsbB1 and PaDsbB2. In vitro reconstitution of the pathway confirms that both PaDsbB1 and PaDsbB2 shuttle electrons from PaDsbA1 to membrane-bound quinones. Accordingly, deletion of both P. aeruginosa dsbB1 (PadsbB1) and PadsbB2 is required to prevent the folding of several P. aeruginosa virulence factors and to lead to a significant decrease in pathogenicity. Using a high-throughput proteomic approach, we also analyzed the impact of PadsbA1 deletion on the global periplasmic proteome of P. aeruginosa, which allowed us to identify more than 20 new potential substrates of this major oxidoreductase. Finally, we report the biochemical and structural characterization of PaDsbA2, a highly oxidizing oxidoreductase, which seems to be expressed under specific conditions. By fully dissecting the machinery that introduces disulfide bonds in P. aeruginosa, our work opens the way to the design of novel antibacterial molecules able to disarm this pathogen by preventing the proper assembly of its arsenal of virulence factors. The human pathogen Pseudomonas aeruginosa causes life-threatening infections in immunodepressed and cystic fibrosis patients. The emergence of P. aeruginosa strains resistant to all of the available antibacterial agents calls for the urgent development of new antibiotics

Gallium-Protoporphyrin IX Inhibits Pseudomonas aeruginosa Growth by Targeting Cytochromes

PubMed Central

Hijazi, Sarah; Visca, Paolo; Frangipani, Emanuela

2017-01-01

Pseudomonas aeruginosa is a challenging pathogen due to both innate and acquired resistance to antibiotics. It is capable of causing a variety of infections, including chronic lung infection in cystic fibrosis (CF) patients. Given the importance of iron in bacterial physiology and pathogenicity, iron-uptake and metabolism have become attractive targets for the development of new antibacterial compounds. P. aeruginosa can acquire iron from a variety of sources to fulfill its nutritional requirements both in the environment and in the infected host. The adaptation of P. aeruginosa to heme iron acquisition in the CF lung makes heme utilization pathways a promising target for the development of new anti-Pseudomonas drugs. Gallium [Ga(III)] is an iron mimetic metal which inhibits P. aeruginosa growth by interfering with iron-dependent metabolism. The Ga(III) complex of the heme precursor protoporphyrin IX (GaPPIX) showed enhanced antibacterial activity against several bacterial species, although no inhibitory effect has been reported on P. aeruginosa. Here, we demonstrate that GaPPIX is indeed capable of inhibiting the growth of clinical P. aeruginosa strains under iron-deplete conditions, as those encountered by bacteria during infection, and that GaPPIX inhibition is reversed by iron. Using P. aeruginosa PAO1 as model organism, we show that GaPPIX enters cells through both the heme-uptake systems has and phu, primarily via the PhuR receptor which plays a crucial role in P. aeruginosa adaptation to the CF lung. We also demonstrate that intracellular GaPPIX inhibits the aerobic growth of P. aeruginosa by targeting cytochromes, thus interfering with cellular respiration. PMID:28184354

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.

Pseudomonas aeruginosa Population Structure Revisited

PubMed Central

Pirnay, Jean-Paul; Bilocq, Florence; Pot, Bruno; Cornelis, Pierre; Zizi, Martin; Van Eldere, Johan; Deschaght, Pieter; Vaneechoutte, Mario; Jennes, Serge; Pitt, Tyrone; De Vos, Daniel

2009-01-01

At present there are strong indications that Pseudomonas aeruginosa exhibits an epidemic population structure; clinical isolates are indistinguishable from environmental isolates, and they do not exhibit a specific (disease) habitat selection. However, some important issues, such as the worldwide emergence of highly transmissible P. aeruginosa clones among cystic fibrosis (CF) patients and the spread and persistence of multidrug resistant (MDR) strains in hospital wards with high antibiotic pressure, remain contentious. To further investigate the population structure of P. aeruginosa, eight parameters were analyzed and combined for 328 unrelated isolates, collected over the last 125 years from 69 localities in 30 countries on five continents, from diverse clinical (human and animal) and environmental habitats. The analysed parameters were: i) O serotype, ii) Fluorescent Amplified-Fragment Length Polymorphism (FALFP) pattern, nucleotide sequences of outer membrane protein genes, iii) oprI, iv) oprL, v) oprD, vi) pyoverdine receptor gene profile (fpvA type and fpvB prevalence), and prevalence of vii) exoenzyme genes exoS and exoU and viii) group I pilin glycosyltransferase gene tfpO. These traits were combined and analysed using biological data analysis software and visualized in the form of a minimum spanning tree (MST). We revealed a network of relationships between all analyzed parameters and non-congruence between experiments. At the same time we observed several conserved clones, characterized by an almost identical data set. These observations confirm the nonclonal epidemic population structure of P. aeruginosa, a superficially clonal structure with frequent recombinations, in which occasionally highly successful epidemic clones arise. One of these clones is the renown and widespread MDR serotype O12 clone. On the other hand, we found no evidence for a widespread CF transmissible clone. All but one of the 43 analysed CF strains belonged to a ubiquitous P

Pseudomonas aeruginosa Dose-Response and Bathing Water Infection

EPA Science Inventory

Pseudomonas aeruginosa is the most commonly identified opportunistic pathogen associated with pool acquired bather disease. To better understand why this microorganism poses this protracted problem we recently appraised P. aeruginosa pool risk management. Much is known about the ...

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.

Antibacterial Activity Of ternary semiconductor compounds AgInSe2 Nanoparticles Synthesized by Simple Chemical Method

NASA Astrophysics Data System (ADS)

Shehab, A. A.; Fadaam, S. A.; Abd, A. N.; Mustafa, M. H.

2018-05-01

In this objective AgInSe2Nanoparticles (AgInSe2 NPs) were prepared by a simple chemical method (SCM). The optica structural l and morphological properties of the synthesized AgInSe2 NPs swere investigated by using UVVI absorption atomic force microscopy AFMmf, Fourier Transform Infrared Spectroscopy and x-ray diffraction. The resistance of bacteria represents a trouble and the outlook for the use of antibiotics in the future until now uncertain. Measures must be taken to decrease this problem. Antibacterial activity of the AgInSe2 nanoparticles were exposed against several pathogenic bacteriaa including Klebsiella pneumonia KPa, Staphylococcus aureus, Bacillus subtili, Enterobacter Cloacae and Esherichia Coliby. Using a good spread method the results showed that AgInSe2 NPs had inhibitory effect versus some pathogenic bacteria with suppression area 18, 14 and 17 mm for SAgInSe2 NPs had an inhibitory effect against S Bacillus Subtilis 11 mm K EnterobactercCloacae 12 mm.

Drug resistance, AmpC-β-lactamase and extended-spectrum β-lactamase-producing Enterobacteriaceae isolated from fish and shrimp

PubMed Central

de Almeida, Marília Viana Albuquerque; Cangussú, Ítalo Mendes; de Carvalho, Antonia Leonadia Siqueira; Brito, Izabelly Linhares Ponte; Costa, Renata Albuquerque

2017-01-01

ABSTRACT The present study aims to detect the production of extended-spectrum beta-lactamases (ESBL) by enterobacteria isolated from samples of fresh shrimp and fish obtained from the retail trade of the city of Sobral, Ceará State, Brazil. All bacterial isolates were submitted to identification and antimicrobial susceptibility testing using aminopenicillin, beta-lactamase inhibitors, carbapenem, 1st, 2nd, 3rd and 4th generation cephalosporins, and monobactam. Three types of beta-lactamases - ESBL, AmpC and KPC - were investigated. 103 strains were identified, and the most frequent species in shrimp and fish samples was Enterobacter cloacae (n = 54). All the strains were resistant to penicillin and more than 50% of the isolates were resistant to ampicillin and cephalothin. Resistance to three 3rd generation cephalosporins (cefotaxime, ceftriaxone and ceftazidime) and one fourth generation cephalosporin (cefepime) was detected in two isolates of E. cloacae from shrimp samples. Phenotypic detection of AmpC was confirmed in seven strains. The ESBL was detected in two strains of E. cloacae from shrimp samples. No strain showed KPC production. These data can be considered alarming, since food (shrimp and fish) may be carriers of enterobacteria resistant to drugs of clinical interest. PMID:29116290

[Application of recombinase polymerase amplification in the detection of Pseudomonas aeruginosa].

PubMed

Jin, X J; Gong, Y L; Yang, L; Mo, B H; Peng, Y Z; He, P; Zhao, J N; Li, X L

2018-04-20

Objective: To establish an optimized method of recombinase polymerase amplification (RPA) to rapidly detect Pseudomonas aeruginosa in clinic. Methods: (1) The DNA templates of one standard Pseudomonas aeruginosa strain was extracted and detected by polymerase chain reaction (PCR), real-time fluorescence quantitative PCR and RPA. Time of sample loading, time of amplification, and time of detection of the three methods were recorded. (2) One standard Pseudomonas aeruginosa strain was diluted in 7 concentrations of 1×10(7,) 1×10(6,) 1×10(5,) 1×10(4,) 1×10(3,) 1×10(2,) and 1×10(1) colony forming unit (CFU)/mL after recovery and cultivation. The DNA templates of Pseudomonas aeruginosa and negative control strain Pseudomonas putida were extracted and detected by PCR, real-time fluorescence quantitative PCR, and RPA separately. The sensitivity of the three methods in detecting Pseudomonas aeruginosa was analyzed. (3) The DNA templates of one standard Pseudomonas aeruginosa strain and four negative control strains ( Staphylococcus aureus, Acinetobacter baumanii, Candida albicans, and Pseudomonas putida ) were extracted separately, and then they were detected by PCR, real-time fluorescence quantitative PCR, and RPA. The specificity of the three methods in detecting Pseudomonas aeruginosa was analyzed. (4) The DNA templates of 28 clinical strains of Pseudomonas aeruginosa preserved in glycerin, 1 clinical strain of which was taken by cotton swab, and negative control strain Pseudomonas putida were extracted separately, and then they were detected by RPA. Positive amplification signals of the clinical strains were observed, and the detection rate was calculated. All experiments were repeated for 3 times. Sensitivity results were analyzed by GraphPad Prism 5.01 statistical software. Results: (1) The loading time of RPA, PCR, and real-time fluorescence quantitative PCR for detecting Pseudomonas aeruginosa were all 20 minutes. In PCR, time of amplification was 98 minutes

Quorum quenching activity in cell-free lysate of endophytic bacteria isolated from Pterocarpus santalinus Linn., and its effect on quorum sensing regulated biofilm in Pseudomonas aeruginosa PAO1.

PubMed

Rajesh, P S; Ravishankar Rai, V

2014-01-01

Quorum sensing mechanism allows the microorganisms to resist the antibiotic treatment by forming biofilms. Quorum quenching is one of the mechanisms to control the development of drug resistance in microbes. Endophyte bacteria are beneficial to plant growth as they support the immune system against the pathogen attack. The endophytic bacteria present in Pterocarpus santalinus were screened for the presence of N-acyl homoserine lactones (AHLs) degrading bacteria using biosensor strains and further confirmed by quantifying the violacein production. Cell-free lysate of endophytic bacteria, Bacillus firmus PT18 and Enterobacter asburiae PT39 exhibited potent AHL degrading ability by inhibiting about 80% violacein production in biosensor strain. Furthermore, when the cell-free lysate was applied to Pseudomonas aeruginosa PAO1 and PAO1-JP2 biofilm it resulted in significant (p<0.01) inhibition of biofilm formation. The biofilm inhibition was confirmed by visualization of biofilm slides under fluorescence microscopy, which showed decrease in total biomass formation in treated slides. Isolation and amplification of the gene (aiiA) indicated that the presence of AHL lactonase in cell-free lysate and sequence alignment indicated that AiiA contains a "HXHXDH" zinc-binding motif that is being conserved in several groups of metallohydrolases. Therefore, the study shows the potential of AHLs degradation by AHL lactonase present in cell-free lysate of isolated endophytic bacteria and inhibition of quorum sensing regulated biofilm formation in P. aeruginosa PAO1. Copyright © 2013 Elsevier GmbH. All rights reserved.

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.

Genetic and Functional Diversity of Pseudomonas aeruginosa Lipopolysaccharide

PubMed Central

Lam, Joseph S.; Taylor, Véronique L.; Islam, Salim T.; Hao, Youai; Kocíncová, Dana

2011-01-01

Lipopolysccharide (LPS) is an integral component of the Pseudomonas aeruginosa cell envelope, occupying the outer leaflet of the outer membrane in this Gram-negative opportunistic pathogen. It is important for bacterium–host interactions and has been shown to be a major virulence factor for this organism. Structurally, P. aeruginosa LPS is composed of three domains, namely, lipid A, core oligosaccharide, and the distal O antigen (O-Ag). Most P. aeruginosa strains produce two distinct forms of O-Ag, one a homopolymer of D-rhamnose that is a common polysaccharide antigen (CPA, formerly termed A band), and the other a heteropolymer of three to five distinct (and often unique dideoxy) sugars in its repeat units, known as O-specific antigen (OSA, formerly termed B band). Compositional differences in the O units among the OSA from different strains form the basis of the International Antigenic Typing Scheme for classification via serotyping of different strains of P. aeruginosa. The focus of this review is to provide state-of-the-art knowledge on the genetic and resultant functional diversity of LPS produced by P. aeruginosa. The underlying factors contributing to this diversity will be thoroughly discussed and presented in the context of its contributions to host–pathogen interactions and the control/prevention of infection. PMID:21687428

Pseudomonas Aeruginosa: Resistance to the Max

PubMed Central

Poole, Keith

2011-01-01

Pseudomonas aeruginosa is intrinsically resistant to a variety of antimicrobials and can develop resistance during anti-pseudomonal chemotherapy both of which compromise treatment of infections caused by this organism. Resistance to multiple classes of antimicrobials (multidrug resistance) in particular is increasingly common in P. aeruginosa, with a number of reports of pan-resistant isolates treatable with a single agent, colistin. Acquired resistance in this organism is multifactorial and attributable to chromosomal mutations and the acquisition of resistance genes via horizontal gene transfer. Mutational changes impacting resistance include upregulation of multidrug efflux systems to promote antimicrobial expulsion, derepression of ampC, AmpC alterations that expand the enzyme's substrate specificity (i.e., extended-spectrum AmpC), alterations to outer membrane permeability to limit antimicrobial entry and alterations to antimicrobial targets. Acquired mechanisms contributing to resistance in P. aeruginosa include β-lactamases, notably the extended-spectrum β-lactamases and the carbapenemases that hydrolyze most β-lactams, aminoglycoside-modifying enzymes, and 16S rRNA methylases that provide high-level pan-aminoglycoside resistance. The organism's propensity to grow in vivo as antimicrobial-tolerant biofilms and the occurrence of hypermutator strains that yield antimicrobial resistant mutants at higher frequency also compromise anti-pseudomonal chemotherapy. With limited therapeutic options and increasing resistance will the untreatable P. aeruginosa infection soon be upon us? PMID:21747788

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

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.

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

Carbapenem Susceptibility and Multidrug-Resistance in Pseudomonas aeruginosa Isolates in Egypt

PubMed Central

Hashem, Hany; Hanora, Amro; Abdalla, Salah; Shawky, Alaa; Saad, Alaa

2016-01-01

Background Resistant Pseudomonas aeruginosa is a serious concern for antimicrobial therapy, as the common isolates exhibit variable grades of resistance, involving beta-lactamase enzymes, beside native defense mechanisms. Objectives The present study was designed to determine the occurrence of Metallo-β- Lactamases (MBL) and Amp C harboring P. aeruginosa isolates from Suez Canal university hospital in Ismailia, Egypt. Methods A total of 147 P. aeruginosa isolates, recovered from 311 patients during a 10-month period, were collected between May 2013 and February 2014; the isolates were collected from urine, wound and sputum. Minimum inhibitory concentration (MIC) determined by agar dilution methods was ≥2 μg/mL for meropenem and imipenem. Identification of P. aeruginosa was confirmed using API 20NE. Metallo-β- Lactamases and Amp C were detected based on different phenotypic methods. Results Overall, 26.5% of P. aeruginosa isolates (39/147) were carbapenem resistant isolates. Furthermore, 64.1% (25/39) were MBL producers, these isolates were screened by the combined disc and disc diffusion methods to determine the ability of MBL production. Both MBL and Amp C harbored P. aeruginosa isolates were 28% (7/25). Sixty-four percent of P. aeruginosa isolates were multidrug resistant (MDR) (16/25). The sensitivity toward polymyxin, imipenem, norfloxacin, piperacillin-tazobactam and gentamicin was 99%, 91%, 88%, 82% and 78%, respectively. The resistance rate towards cefotaxime, ceftazidime, cefepime, aztreonam and meropenem was 98.6%, 86%, 71.4%, 34% and 30%, respectively. Conclusions Multidrug resistance was significantly associated with MBL production in P. aeruginosa. Early detection of MBL-producing P. aeruginosa and hospital antibiotic policy prescription helps proper antimicrobial therapy and avoidance of dissemination of these multidrug resistance isolates. PMID:28138370

Carbapenem Susceptibility and Multidrug-Resistance in Pseudomonas aeruginosa Isolates in Egypt.

PubMed

Hashem, Hany; Hanora, Amro; Abdalla, Salah; Shawky, Alaa; Saad, Alaa

2016-11-01

Resistant Pseudomonas aeruginosa is a serious concern for antimicrobial therapy, as the common isolates exhibit variable grades of resistance, involving beta-lactamase enzymes, beside native defense mechanisms. The present study was designed to determine the occurrence of Metallo-β- Lactamases (MBL) and Amp C harboring P. aeruginosa isolates from Suez Canal university hospital in Ismailia, Egypt. A total of 147 P. aeruginosa isolates, recovered from 311 patients during a 10-month period, were collected between May 2013 and February 2014; the isolates were collected from urine, wound and sputum. Minimum inhibitory concentration (MIC) determined by agar dilution methods was ≥2 μg/mL for meropenem and imipenem. Identification of P. aeruginosa was confirmed using API 20NE. Metallo-β- Lactamases and Amp C were detected based on different phenotypic methods. Overall, 26.5% of P. aeruginosa isolates (39/147) were carbapenem resistant isolates. Furthermore, 64.1% (25/39) were MBL producers, these isolates were screened by the combined disc and disc diffusion methods to determine the ability of MBL production. Both MBL and Amp C harbored P. aeruginosa isolates were 28% (7/25). Sixty-four percent of P. aeruginosa isolates were multidrug resistant (MDR) (16/25). The sensitivity toward polymyxin, imipenem, norfloxacin, piperacillin-tazobactam and gentamicin was 99%, 91%, 88%, 82% and 78%, respectively. The resistance rate towards cefotaxime, ceftazidime, cefepime, aztreonam and meropenem was 98.6%, 86%, 71.4%, 34% and 30%, respectively. Multidrug resistance was significantly associated with MBL production in P. aeruginosa . Early detection of MBL-producing P. aeruginosa and hospital antibiotic policy prescription helps proper antimicrobial therapy and avoidance of dissemination of these multidrug resistance isolates.

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.

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.

[Prostate histopathology of NIH category IV prostatitis detected by sextant prostate needle biopsy from the patients with high prostatic specific antigen].

PubMed

Shimomura, Tatsuya; Kiyota, Hiroshi; Takahashi, Hiroyuki; Madarame, Jun; Kimura, Takahiro; Onodera, Shouichi

2003-08-01

Asymptomatic prostatitis is classified as category IV in NIH classification of prostatitis syndrome (1999). No report concerning this category has been present. We investigated this category histopathologically and clinically, in order to clarify the histopathological distribution and its correlation to the clinical features, in this study. Among 785 patients who were suspected prostate cancer because of their high prostatic specific antigen (PSA) values and to have a sextant prostate needle biopsy was performed between January, 1996 and December, 2000, 88 patients (11.2%) were diagnosed as NIH category IV prostatitis (asymptomatic prostatitis). We observed all pathological specimens stained with Hematoxylin-Eosine, and classified them into subtypes according to the classification criteria for prostatitis defined by True et al. (1999). We also investigated the relationship between histopathological distribution and clinical features such as PSA values, PSA density, the incidence of pyuria or bacteriuria. In the histopathological study, grade distributions were 12.5% (11/88) in mild, 71.6% (63/88) in moderate, and 15.9% (14/88) in severe. Location distributions were 2.3% (2/88) in glandular, 68.2% (60/88) in periglandular, and 29.5% (26/88) in stromal. No relationship between these subtypes and clinical features was recognized statistically. However, 7 patients (7.95%) were diagnosed as prostate cancers, later. Pyuria was found in 29.1% (23/79). Bacteriuria was present in 14.3% (11/77). Isolated bacteria were 4 strains of Enterococcus faccalis, 2 strains of each of Pseudomonas aeruginosa and Staphylococcus aureus, and one strain of each of Escherichia coli, Klebsiella oxytoca, Enterobacter cloacae, Enterobacter aerogenes, Staphylococcus haemolyticus, and Staphylococcus epidermidis. Gram positive rod, and Candida sp. No relationship between these subtypes and bacterial species was recognized. These results indicated that the incidence of NIII category IV prostatits

Why Does the Healthy Cornea Resist Pseudomonas aeruginosa Infection?

PubMed Central

Evans, David J.; Fleiszig, Suzanne M. J.

2013-01-01

Purpose To provide our perspective on why the cornea is resistant to infection based on our research results with Pseudomonas aeruginosa. Perspective We focus on our current understanding of the interplay between bacteria, tear fluid and the corneal epithelium that determine health as the usual outcome, and propose a theoretical model for how contact lens wear might change those interactions to enable susceptibility to P. aeruginosa infection. Methods Use of “null-infection” in vivo models, cultured human corneal epithelial cells, contact lens-wearing animal models, and bacterial genetics help to elucidate mechanisms by which P. aeruginosa survive at the ocular surface, adheres, and traverses multilayered corneal epithelia. These models also help elucidate the molecular mechanisms of corneal epithelial innate defense. Results and Discussion Tear fluid and the corneal epithelium combine to make a formidable defense against P. aeruginosa infection of the cornea. Part of that defense involves the expression of antimicrobials such as β-defensins, the cathelicidin LL-37, cytokeratin-derived antimicrobial peptides, and RNase7. Immunomodulators such as SP-D and ST2 also contribute. Innate defenses of the cornea depend in part on MyD88, a key adaptor protein of TLR and IL-1R signaling, but the basal lamina represents the final barrier to bacterial penetration. Overcoming these defenses involves P. aeruginosa adaptation, expression of the type three secretion system, proteases, and P. aeruginosa biofilm formation on contact lenses. Conclusion After more than two decades of research focused on understanding how contact lens wear predisposes to P. aeruginosa infection, our working hypothesis places blame for microbial keratitis on bacterial adaptation to ocular surface defenses, combined with changes to the biochemistry of the corneal surface caused by trapping bacteria and tear fluid against the cornea under the lens. PMID:23601656

Chromosomally Encoded mcr-5 in Colistin non-susceptible Pseudomonas aeruginosa.

PubMed

Snesrud, Erik; Maybank, Rosslyn; Kwak, Yoon I; Jones, Anthony R; Hinkle, Mary K; Mc Gann, Patrick

2018-05-29

Whole genome sequencing (WGS) of historical Pseudomonas aeruginosa clinical isolates identified a chromosomal copy of mcr-5 within a Tn 3 -like transposon in P. aeruginosa MRSN 12280. The isolate was non-susceptible to colistin by broth microdilution and genome analysis revealed no mutations known to confer colistin resistance. To the best of our knowledge, this is the first report of mcr in colistin non-susceptible P. aeruginosa .

The Genomic Basis of Evolutionary Innovation in Pseudomonas aeruginosa

PubMed Central

Wagner, Andreas; MacLean, R. Craig

2016-01-01

Novel traits play a key role in evolution, but their origins remain poorly understood. Here we address this problem by using experimental evolution to study bacterial innovation in real time. We allowed 380 populations of Pseudomonas aeruginosa to adapt to 95 different carbon sources that challenged bacteria with either evolving novel metabolic traits or optimizing existing traits. Whole genome sequencing of more than 80 clones revealed profound differences in the genetic basis of innovation and optimization. Innovation was associated with the rapid acquisition of mutations in genes involved in transcription and metabolism. Mutations in pre-existing duplicate genes in the P. aeruginosa genome were common during innovation, but not optimization. These duplicate genes may have been acquired by P. aeruginosa due to either spontaneous gene amplification or horizontal gene transfer. High throughput phenotype assays revealed that novelty was associated with increased pleiotropic costs that are likely to constrain innovation. However, mutations in duplicate genes with close homologs in the P. aeruginosa genome were associated with low pleiotropic costs compared to mutations in duplicate genes with distant homologs in the P. aeruginosa genome, suggesting that functional redundancy between duplicates facilitates innovation by buffering pleiotropic costs. PMID:27149698

[Inhibition effects of Houttuynia cordata Thunb. on Microcystis aeruginosa].

PubMed

Liu, Lu; Li, Cheng; Xia, Wentong; Yang, Xiaohui; Zhang, Tingting

2014-05-01

To research the inhibitory effect of Houttuynia cordata Thunb. on Microcystis aeruginosa. M. aeruginosat were treated respectively by H. cordata leaching solution or H. cordata extracts. H. cordata leaching solution extracted by water and the H. cordata extracts extracted by organic solvent (acetone, ethyl acetate, petroleum ether and ethanol, respectively). The inhibition ratios were calculated according to the M. aeruginosa densities, and the allelochemicals of the extract that had the best inhibitiory effect on M. aeruginosa were identified by GC-MS analysis. It was proved that leaching solution of H. cordata and four crude extracts had good inhibitory effect on M. aeruginosa. The inhibitory effects of the four crude extracts were the fraction extracted by ethyl acetate, the fraction extracted by ethanol, the fraction extracted by acetone and the fraction extracted by petroleum ether form strong to weak in turn. Then, the allelochemicals of the fraction extracted by ethyl acetate were indentified, mainly including acetonyldimethylcarbinol, 2,2-dimethyl-3-hexanone, 6-chlorohexanoic and 4-cyanophenyl ester. H. cordata has strong inhibitory effect on water-blooming cyanobacteria and the potential to develop into an ecological M. aeruginosa inhibiting agent.

In Vitro Assessment of the Antimicrobial Efficacy of Optimized Nitroglycerin-Citrate-Ethanol as a Nonantibiotic, Antimicrobial Catheter Lock Solution for Prevention of Central Line-Associated Bloodstream Infections.

PubMed

Reitzel, Ruth A; Rosenblatt, Joel; Hirsh-Ginsberg, Cheryl; Murray, Kimberly; Chaftari, Anne-Marie; Hachem, Ray; Raad, Issam

2016-09-01

The rapid, broad-spectrum, biofilm-eradicating activity of the combination of 0.01% nitroglycerin, 7% citrate, and 20% ethanol and its potential as a nonantibiotic, antimicrobial catheter lock solution (ACLS) were previously reported. Here, a nitroglycerin-citrate-ethanol (NiCE) ACLS optimized for clinical assessment was developed by reducing the nitroglycerin and citrate concentrations and increasing the ethanol concentration. Biofilm-eradicating activity was sustained when the ethanol concentration was increased from 20 to 22% which fully compensated for reducing the citrate concentration from 7% to 4% as well as the nitroglycerin concentration from 0.01% to 0.0015% or 0.003%. The optimized formulations demonstrated complete and rapid (2 h) eradication of methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-intermediate Staphylococcus aureus (VISA), methicillin-resistant Staphylococcus epidermidis (MRSE), vancomycin-resistant enterococci (VRE), multidrug-resistant (MDR) Pseudomonas aeruginosa, MDR Klebsiella pneumoniae, MDR Enterobacter cloacae, MDR Acinetobacter baumannii, MDR Escherichia coli, MDR Stenotrophomonas maltophilia, Candida albicans, and Candida glabrata biofilms. The optimized NiCE lock solutions demonstrated anticoagulant activities comparable to those of heparin lock solutions. NiCE lock solution was significantly more effective than taurolidine-citrate-heparin lock solution in eradicating biofilms of Staphylococcus aureus and Candida glabrata The optimized, nonantibiotic, heparin-free NiCE lock solution demonstrates rapid broad-spectrum biofilm eradication as well as effective anticoagulant activity, making NiCE a high-quality ACLS candidate for clinical assessment. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Antimicrobial activity of octenidine against multidrug-resistant Gram-negative pathogens.

PubMed

Alvarez-Marin, R; Aires-de-Sousa, M; Nordmann, P; Kieffer, N; Poirel, L

2017-12-01

Multidrug-resistant (MR) Gram-negative (GN) pathogens pose a major and growing threat for healthcare systems, as therapy of infections is often limited due to the lack of available systemic antibiotics. Well-tolerated antiseptics, such as octenidine dihydrochloride (OCT), may be a very useful tool in infection control to reduce the dissemination of MRGN. This study aimed to investigate the bactericidal activity of OCT against international epidemic clones of MRGN. A set of five different species (Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Acinetobacter baumannii, and Pseudomonas aeruginosa) was studied to prove OCT efficacy without organic load, under "clean conditions" (0.3 g/L albumin) and under "dirty conditions" (3 g/L albumin + 3 mL/L defibrinated sheep blood), according to an official test norm (EN13727). We used five clonally unrelated isolates per species, including a susceptible wild-type strain, and four MRGN isolates, corresponding to either the 3MRGN or 4MRGN definition of multidrug resistance. A contact time of 1 min was fully effective for all isolates by using different OCT concentrations (0.01% and 0.05%), with a bacterial reduction factor of >5 log 10 systematically observed. Growth kinetics were determined with two different wild-type strains (A. baumannii and K. pneumoniae), proving a time-dependent efficacy of OCT. These results highlight that OCT may be extremely useful to eradicate emerging highly resistant Gram-negative pathogens associated with nosocomial infections.

Chronic Pseudomonas aeruginosa infection and respiratory muscle impairment in cystic fibrosis.

PubMed

Dassios, Theodore G; Katelari, Anna; Doudounakis, Stavros; Dimitriou, Gabriel

2014-03-01

Chronic infection with Pseudomonas aeruginosa in patients with cystic fibrosis (CF) is associated with increased morbidity. Chronic infection can cause limb and respiratory muscle compromise. Respiratory muscle function can be assessed via maximal inspiratory pressure (PImax), maximal expiratory pressure (PEmax), and the pressure-time index of the respiratory muscles (PTImus). We studied the effect of chronic P. aeruginosa infection on respiratory muscle function in patients with CF. This cross-sectional study assessed PImax, PEmax, PTImus, FEV1, FVC, maximum expiratory flow during the middle half of the FVC maneuver, body mass index, and upper arm muscle area in 122 subjects with CF, in 4 subgroups matched for age and sex at different stages of P. aeruginosa infection, according to the Leeds criteria. We compared respiratory muscle function in the subgroups according to P. aeruginosa infection state. Median PImax was significantly lower in CF subjects with chronic P. aeruginosa infection (PImax = 62 cm H2O), compared to subjects who were never infected (PImax = 86 cm H2O, P = .02), free of infection (PImax = 74 cm H2O, P = .01), or intermittently infected (PImax = 72 cm H2O, P = .02). Median PTImus was significantly increased in CF subjects with chronic P. aeruginosa infection (PTImus = .142), compared to subjects who were free of infection (PTImus = .102, P = .006). Median upper-arm muscle area was significantly lower in CF subjects with chronic P. aeruginosa infection (upper-arm muscle area = 2,219 mm(2)), compared to subjects who were never infected (2,754 mm(2), P = .03), free of infection (2,678 mm(2), P = .01), or intermittently infected (2,603 mm(2), P = .04). Multivariate logistic regression revealed P. aeruginosa state of infection as a significant determinant of PTImus (P = .03) independently of sex, upper-arm muscle area, and FEV1. CF subjects with chronic P. aeruginosa infection exhibited impaired respiratory muscle function and decreased inspiratory

[In vitro antibacterial activity of a new parenteral penem, sulopenem].

PubMed

Yoshida, T; Tateda, E; Hiramatsu, K; Yokota, T

1996-04-01

Eighty percent minimum inhibitory concentrations (MIC80) of sulopenem against clinically isolated 12 to 80 strains of each of different bacteria were as follows: methicillin-susceptible Staphylococcus aureus (MSSA): 0.20 micrograms/ml, methicillin-resistant S. aureus (MRSA): 50 micrograms/ml, coagulase-negative staphylococci: 3.13 micrograms/ml, Streptococcus pyogenes: < or = 0.013 microgram/ml, Streptococcus pneumoniae: < or = 0.013 microgram/ml, beta-streptococci: 0.05 microgram/ml, Enterococcus faecalis: 12.5 micrograms/ml, Enterococcus faecium: > 100 micrograms/ml, Escherichia coli CS2(R+): 0.10 microgram/ml, Klebsiella pneumoniae: 0.05 microgram/ml, Proteus mirabilis: 0.10 microgram/ml, Proteus vulgaris: 0.20 microgram/ml, Morganella morganii: 0.39 micrograms/ml, Providencia rettgeri: 3.13 micrograms/ml, Citrobacter freundii: 0.20 microgram/ml, Enterobacter cloacae: 0.39 microgram/ml, Serratia marcescens: 1.56 micrograms/ml, Pseudomonas aeruginosa: 50 micrograms/ml, Pseudomonas cepacia: 3.13 micrograms/ml, Xanthomonas maltophilia: > 100 micrograms/ml, Acinetobacter calcoaceticus: 1.56 micrograms/ml, ampicillin-resistant Haemophilus influenzae: 0.39 microgram/ml and Bacteroides fragil is: 0.20 microgram/ml, respectively. Sulopenem possesses a stronger activity than flomoxef or cefuzonam against Gram-positive bacteria, the strongest activity among the antibiotics tested against Gram-negative bacteria except P. aeruginosa. Sulopenem has stronger affinities than imipenem to all fractions of PBPs of S. aureus, E. coli, P. vulgaris, S. marcescens, even of P. aeruginosa. Affinities of sulopenem to PBPs-1 and -3 of S. aureus, PBP-2 of E. coli were much stronger than those of imipenem (IPM). Sulopenem generally has small Ki values to all types of beta-lactamases and also has stronger permanent inactivation effect to Ia and IIb types of beta-lactamases than IPM. No synergistic bactericidal activity of sulopenem was apparent with serum complement. However, synergism of

Influence of host seed on metabolic activity by Enterobacter cloacae in the spermosphere

USDA-ARS?s Scientific Manuscript database

Little is known regarding the influences of nutrients released from plants on the metabolic activity of colonizing microbes. To gain a better understanding of these influences, we used bioluminescence- and oxygen consumption-based methods to compare bacterial metabolic activity expressed during col...

Network-assisted investigation of virulence and antibiotic-resistance systems in Pseudomonas aeruginosa

NASA Astrophysics Data System (ADS)

Hwang, Sohyun; Kim, Chan Yeong; Ji, Sun-Gou; Go, Junhyeok; Kim, Hanhae; Yang, Sunmo; Kim, Hye Jin; Cho, Ara; Yoon, Sang Sun; Lee, Insuk

2016-05-01

Pseudomonas aeruginosa is a Gram-negative bacterium of clinical significance. Although the genome of PAO1, a prototype strain of P. aeruginosa, has been extensively studied, approximately one-third of the functional genome remains unknown. With the emergence of antibiotic-resistant strains of P. aeruginosa, there is an urgent need to develop novel antibiotic and anti-virulence strategies, which may be facilitated by an approach that explores P. aeruginosa gene function in systems-level models. Here, we present a genome-wide functional network of P. aeruginosa genes, PseudomonasNet, which covers 98% of the coding genome, and a companion web server to generate functional hypotheses using various network-search algorithms. We demonstrate that PseudomonasNet-assisted predictions can effectively identify novel genes involved in virulence and antibiotic resistance. Moreover, an antibiotic-resistance network based on PseudomonasNet reveals that P. aeruginosa has common modular genetic organisations that confer increased or decreased resistance to diverse antibiotics, which accounts for the pervasiveness of cross-resistance across multiple drugs. The same network also suggests that P. aeruginosa has developed mechanism of trade-off in resistance across drugs by altering genetic interactions. Taken together, these results clearly demonstrate the usefulness of a genome-scale functional network to investigate pathogenic systems in P. aeruginosa.

Expansion of Antibacterial Spectrum of Muraymycins toward Pseudomonas aeruginosa.

PubMed

Takeoka, Yusuke; Tanino, Tetsuya; Sekiguchi, Mitsuaki; Yonezawa, Shuji; Sakagami, Masahiro; Takahashi, Fumiyo; Togame, Hiroko; Tanaka, Yoshikazu; Takemoto, Hiroshi; Ichikawa, Satoshi; Matsuda, Akira

2014-05-08

It is urgent to develop novel anti-Pseudomonas agents that should also be active against multidrug resistant P. aeruginosa. Expanding the antibacterial spectrum of muraymycins toward P. aeruginosa was investigated by the systematic structure-activity relationship study. It was revealed that two functional groups, a lipophilic side chain and a guanidino group, at the accessory moiety of muraymycins were important for the anti-Pseudomonas activity, and analogue 29 exhibited antibacterial activity against a range of P. aeruginosa strains with the minimum inhibitory concentration values of 4-8 μg/mL.

Expansion of Antibacterial Spectrum of Muraymycins toward Pseudomonas aeruginosa

PubMed Central

2014-01-01

It is urgent to develop novel anti-Pseudomonas agents that should also be active against multidrug resistant P. aeruginosa. Expanding the antibacterial spectrum of muraymycins toward P. aeruginosa was investigated by the systematic structure–activity relationship study. It was revealed that two functional groups, a lipophilic side chain and a guanidino group, at the accessory moiety of muraymycins were important for the anti-Pseudomonas activity, and analogue 29 exhibited antibacterial activity against a range of P. aeruginosa strains with the minimum inhibitory concentration values of 4–8 μg/mL. PMID:24900879

Gallbladder microbiota variability in Colombian gallstones patients.

PubMed

Arteta, Ariel Antonio; Carvajal-Restrepo, Hernan; Sánchez-Jiménez, Miryan Margot; Diaz-Rodriguez, Sergio; Cardona-Castro, Nora

2017-03-31

Gallbladder stones are a very frequently occurring condition. Despite bile bactericidal activity, many bacteria have been detected inside the gallbladder, and gallstones facilitate their presence. Between 3% and 5% of the patients with Salmonella spp. infection develop the carrier stage, with the bacteria persisting inside the gallbladder, shedding bacteria in their feces without signs of infection. The aim of this study was to isolate bacteria from Colombian patients with gallstones, using standard culturing methods, and to identify Salmonella spp. carriers by molecular techniques. A total of 149 patients (120 female and 29 male) diagnosed with gallstones who underwent cholecystectomy and who did not have symptoms of acute inflammation were included. Gallbladder tissue and bile were cultured and used for DNA extraction and Salmonella spp. hilA gene detection. Of the 149 patients 28 (19%) had positive cultures. Twenty-one (75%) patients with positive cultures were from Medellin's metropolitan area. In this geographical location, the most frequent isolations were Pseudomonas spp. (38%), Klebsiella spp. (23%), and Proteus spp. (9%) in addition to unique cases of other bacteria. In Apartado, the isolates found were Enterobacter cloacae (50%), Raoultella terrigena (32%), and both Enterobacter cloacae and Raoultella terrigena were isolated in one (18%) male patient. Five (3.3%) of the 149 patients had positive polymerase chain reaction (PCR) results for the hilA gene of Salmonella spp., all of whom were female and residents of the Medellín metropolitan area. The gallbladder microbiota variability found could be related to geographical, ethnic, and environmental conditions.

Geographical differences in first acquisition of Pseudomonas aeruginosa in cystic fibrosis.

PubMed

Ranganathan, Sarath C; Skoric, Billy; Ramsay, Kay A; Carzino, Rosemary; Gibson, Anne-Marie; Hart, Emily; Harrison, Jo; Bell, Scott C; Kidd, Timothy J

2013-04-01

Risk of infection with Pseudomonas aeruginosa in cystic fibrosis (CF) may be associated with environmental factors. To determine whether residential location is associated with risk of first acquisition of P. aeruginosa. We performed bronchoalveolar lavage and upper airway cultures in children newly diagnosed with CF to identify infection with P. aeruginosa during infancy and early childhood. Children were assessed according to their residence in a regional or metropolitan area. Multilocus sequence typing was used to determine P. aeruginosa genotype. An environmental questionnaire was also administered. A total of 105 of 120 (87.5%) infants diagnosed with CF were included in this study. Diagnosis in 65 infants (61.9%) followed newborn screening at mean age of 4.6 weeks. Sixty subjects (57.1%) were homozygous ΔF508, and 47 (44.8%) were female. Fifty-five (52.3%) infants were regional, of whom 26 (47.3%), compared with 9 of 50 (18.0%) metropolitan children, acquired infection with P. aeruginosa (odds ratio, 4.084; 95% confidence interval, 1.55-11.30). Age at acquisition was similar (regional: median, 2.31 yr; range, 0.27-5.96 yr; metropolitan: median, 3.10 yr, range, 0.89-3.70 yr). Strain typing identified P. aeruginosa genotypes often encountered in different ecological settings and little evidence of cross-infection. Ninety questionnaires (85.7%) were completed. Those who acquired P. aeruginosa were more likely to be living in a household that used water sprinkler systems (P = 0.032), but no differences were identified to explain increased risk of acquisition of P. aeruginosa in regional children. Geographical difference in residence of children with CF was associated with increased risk of first acquisition of P. aeruginosa, usually with strains associated with the environment rather than with cross-infection.

Relevance of multidrug-resistant Pseudomonas aeruginosa infections in cystic fibrosis.

PubMed

Stefani, S; Campana, S; Cariani, L; Carnovale, V; Colombo, C; Lleo, M M; Iula, V D; Minicucci, L; Morelli, P; Pizzamiglio, G; Taccetti, G

2017-09-01

Multidrug-resistant (MDR) Pseudomonas aeruginosa is an important issue for physicians who take care of patients with cystic fibrosis (CF). Here, we review the latest research on how P. aeruginosa infection causes lung function to decline and how several factors contribute to the emergence of antibiotic resistance in P. aeruginosa strains and influence the course of the infection course. However, many aspects of the practical management of patients with CF infected with MDR P. aeruginosa are still to be established. Less is known about the exact role of susceptibility testing in clinical strategies for dealing with resistant infections, and there is an urgent need to find a tool to assist in choosing the best therapeutic strategy for MDR P. aeruginosa infection. One current perception is that the selection of antibiotic therapy according to antibiogram results is an important component of the decision-making process, but other patient factors, such as previous infection history and antibiotic courses, also need to be evaluated. On the basis of the known issues and the best current data on respiratory infections caused by MDR P. aeruginosa, this review provides practical suggestions to optimize the diagnostic and therapeutic management of patients with CF who are infected with these pathogens. Copyright © 2017 Elsevier GmbH. All rights reserved.

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.

Engineering waterborne Pseudomonas aeruginosa out of a critical care unit.

PubMed

Garvey, Mark I; Bradley, Craig W; Wilkinson, Martyn A C; Bradley, Christina; Holden, Elisabeth

2017-08-01

To describe engineering and holistic interventions on water outlets contaminated with Pseudomonas aeruginosa and the observed impact on clinical P. aeruginosa patient isolates in a large Intensive Care Unit (ICU). Descriptive study. Queen Elizabeth Hospital Birmingham (QEHB), part of University Hospitals Birmingham (UHB) NHS Foundation Trust is a tertiary referral teaching hospital in Birmingham, UK and provides clinical services to nearly 1 million patients every year. Breakpoint models were used to detect any significant changes in the cumulative yearly rates of clinical P. aeruginosa patient isolates from August 2013-December 2016 across QEHB. Water sampling undertaken on the ICU indicated 30% of the outlets were positive for P. aeruginosa at any one time. Molecular typing of patient and water isolates via Pulsed Field Gel Electrophoresis suggested there was a 30% transmission rate of P. aeruginosa from the water to patients on the ICU. From, February 2014, QEHB implemented engineering interventions, consisting of new tap outlets and PALL point-of-use filters; as well as holistic measures, from February 2016 including a revised tap cleaning method and appropriate disposal of patient waste water. Breakpoint models indicated the engineering and holistic interventions resulted in a significant (p<0.001) 50% reduction in the number of P. aeruginosa clinical patient isolates over a year. Here we demonstrate that the role of waterborne transmission of P. aeruginosa in an ICU cannot be overlooked. We suggest both holistic and environmental factors are important in reducing transmission. Copyright © 2017 Elsevier GmbH. All rights reserved.

Transferable Drug Resistance in Pseudomonas aeruginosa1

PubMed Central

Bryan, L. E.; Elzen, H. M. Van Den; Tseng, Jui Teng

1972-01-01

Three strains of Pseudomonas aeruginosa were demonstrated to transfer double-drug resistance by conjugation to a P. aeruginosa recipient at frequencies of 10−4 to 10−2 per recipient cell. Two of the three strains also transferred to Escherichia coli at frequencies which were 103- to 105-fold lower, but the third strain could not be demonstrated to do so. The latter strain, however, conferred maleness on the Pseudomonas recipient. The transfer of streptomycin resistance was associated with the acquisition of streptomycin phosphorylase by both P. aeruginosa and E. coli recipients. Maximal broth mating frequencies were obtained with nonagitated cultures less than 1 mm in depth. A pyocine selection system based on donor sensitivity and recipient resistance is described and appears to have future value as a generalized selective device for use after matings. PMID:4207756

Pseudomonas aeruginosa Genotype Prevalence in Dutch Cystic Fibrosis Patients and Age Dependency of Colonization by Various P. aeruginosa Sequence Types ▿

PubMed Central

van Mansfeld, Rosa; Willems, Rob; Brimicombe, Roland; Heijerman, Harry; van Berkhout, Ferdinand Teding; Wolfs, Tom; van der Ent, Cornelis; Bonten, Marc

2009-01-01

The patient-to-patient transmission of highly prevalent Pseudomonas aeruginosa clones which are associated with enhanced disease progression has led to strict segregation policies for cystic fibrosis (CF) patients in many countries. However, little is known about the population structure of P. aeruginosa among CF patients. The aim of the present cross-sectional study was to determine the prevalence and genetic relatedness of P. aeruginosa isolates from CF patients who visited two major CF centers in The Netherlands in 2007 and 2008. These patients represented 45% of the Dutch CF population. P. aeruginosa carriage in the respiratory tract was determined by standard microbiological culture techniques, and all phenotypically different isolates in the first specimens recovered in 2007 and 2008 were genotyped by multilocus sequence typing. A total of 313 (57%) of 551 patients whose samples were cultured carried P. aeruginosa. Two sequence types (STs), ST406 and ST497, were found in 15% and 5% of the patients, respectively, and 60% of the patients harbored a strain that was also found in at least two other patients. The risk ratios for carrying ST406 and ST497 were 17.8 (95% confidence interval [CI], 7.2 to 43.6) for those aged between 15 and 24 years and 6 (95% CI, 1.4 to 26.1) for those aged >25 years. ST406 and ST497 were not genetically linked to previously described epidemic clones, which were also not found in this CF population. The population structure of P. aeruginosa in Dutch CF patients is characterized by the presence of two prevalent STs that are associated with certain age groups and that are not genetically linked to previously described epidemic clones. PMID:19828746

[Risk factors for Pseudomonas aeruginosa infections, resistant to carbapenem].

PubMed

Ghibu, Laura; Miftode, Egidia; Teodor, Andra; Bejan, Codrina; Dorobăţ, Carmen Mihaela

2010-01-01

Since their introduction in clinical practice,carbapenems have been among the most powerful antibiotics for treating serious infections cased by Gram-negative nosocomial pathogens, including Pseudomonas aeruginosa. The emergence of betalactamases with carbapenem-hydrolyzing activity is of major clinical concern. Pseudomonas aeruginosa is a leading cause of nosocomial infection. Risk factors for colonization with carbapenems-resistant Pseudomonas in hospital are: history of P. aeruginosa infection or colonization within the previous year, (length of hospital stay, being bedridden or in the ICU, mechanical ventilation, malignant disease, and history of chronic obstructive pulmonary disease have all been identified as independent risk factors for MDR P. aeruginosa infection. Long-term-care facilities are also reservoirs of resistant bacteria. Risk factors for colonization of LTCF residents with resistant bacteria included age > 86 years, antibiotic treatment in the previous 3 months, indwelling devices, chronic obstructive pulmonary disease, physical disability, and the particular LTCF unit.

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.

Screening, nutritional optimization and purification for phytase produced by Enterobacter aerogenes and its role in enhancement of hydrocarbons degradation and biofilm inhibition.

PubMed

Muslim, Sahira Nsayef; Mohammed Ali, Alaa Naseer; Al-Kadmy, Israa M S; Khazaal, Saba Saadoon; Ibrahim, Susan A; Al-Saryi, Nadal A; Al-Saadi, Luma Ghaeb; Muslim, Sraa Nsayef; Salman, Batool Kadham; Aziz, Sarah Naji

2018-02-01

In this study, a novel isolate of Enterobacter aerogenes isolated from contaminated soils with hydrocarbons had extracellular phytate-degrading activity. Enterobacter aerogenes isolates were identified by biochemical tests and confirmed by16S rRNA gene products (amplified size 211bp) for genotypic detection. The phytase activity was reached to maximum activity when this isolate was cultivated under the optimal conditions which consisted of using minimal salt medium containing 1%(w/v) rice bran as a sole source for carbon and 2% (w/v) yeast extract at pH 5.5 and temperature of 50°C for 48 h. The phytase had purified to homogeneity by 50% ammonium sulphate precipitation, ion exchange and gel filtration chromatography with 75.7 fold of purification and a yield of 30.35%. The purified phytase is a single peptide with approximate molecular mass of 42 kDa as assessed by SDS-PAGE. The highest degradative ability by Enterobacter aerogenes of black oil, white oil and used engine oil had observed after 72 h of incubation. Rapid degradation of black oil and used engine oil had also observed while slow degradation of white oilat all time of incubation. The purified phytase inhibited biofilm formation ability in a dose-dependent manner for all Gram-negative and Gram-positive biofilm-forming bacteria and a significant difference in cell surface hydrophobicity was observed after exposure of planktonic cells to phytase for hour. The hydrolyzing effect of phytase released by Enterobacter aerogenes for complex salts of phosphorus that are insoluble in the soil led to increase of phosphorus concentrations and enhanced the ability of Enterobacter aerogenes to degrade a specific hydrocarbon in contaminated soil so that the phytase has a promising application in bioremediation of contaminated soils with hydrocarbons. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pseudomonas aeruginosa uses T3SS to inhibit diabetic wound healing.

PubMed

Goldufsky, Josef; Wood, Stephen J; Jayaraman, Vijayakumar; Majdobeh, Omar; Chen, Lin; Qin, Shanshan; Zhang, Chunxiang; DiPietro, Luisa A; Shafikhani, Sasha H

2015-01-01

Diabetic foot ulcers are responsible for more hospitalizations than any other complication of diabetes. Bacterial infection is recognized as an important factor associated with impaired healing in diabetic ulcers. Pseudomonas aeruginosa is the most frequently detected Gram-negative pathogen in diabetic ulcers. P. aeruginosa infection has been shown to impair healing in diabetic wounds in a manner that correlates with its ability to form biofilm. While the majority of infections in diabetic ulcers are biofilm associated, 33% of infections are nonbiofilm in nature. P. aeruginosa is the most prevalent Gram-negative pathogen in all diabetic wound types, which suggests that the deleterious impact of P. aeruginosa on healing in diabetic wounds goes beyond its ability to form biofilm and likely involves other factors. The Type III Secretion System (T3SS) virulence structure is required for the pathogenesis of all P. aeruginosa clinical isolates, suggesting that it may also play a role in the inhibition of wound repair in diabetic skin ulcers. We evaluated the role of T3SS in mediating P. aeruginosa-induced tissue damage in the wounds of diabetic mice. Our data demonstrate that P. aeruginosa establishes a robust and persistent infection in diabetic wounds independent of its ability to form biofilm and causes severe wound damage in a manner that primarily depends on its T3SS. © 2015 by the Wound Healing Society.

Bacteriophage Infectivity Against Pseudomonas aeruginosa in Saline Conditions

PubMed Central

Scarascia, Giantommaso; Yap, Scott A.; Kaksonen, Anna H.; Hong, Pei-Ying

2018-01-01

Pseudomonas aeruginosa is a ubiquitous member of marine biofilm, and reduces thiosulfate to produce toxic hydrogen sulfide gas. In this study, lytic bacteriophages were isolated and applied to inhibit the growth of P. aeruginosa in planktonic mode at different temperature, pH, and salinity. Bacteriophages showed optimal infectivity at a multiplicity of infection of 10 in saline conditions, and demonstrated lytic abilities over all tested temperature (25, 30, 37, and 45°C) and pH 6–9. Planktonic P. aeruginosa exhibited significantly longer lag phase and lower specific growth rates upon exposure to bacteriophages. Bacteriophages were subsequently applied to P. aeruginosa-enriched biofilm and were determined to lower the relative abundance of Pseudomonas-related taxa from 0.17 to 5.58% in controls to 0.01–0.61% in treated microbial communities. The relative abundance of Alphaproteobacteria, Pseudoalteromonas, and Planococcaceae decreased, possibly due to the phage-induced disruption of the biofilm matrix. Lastly, when applied to mitigate biofouling of ultrafiltration membranes, bacteriophages were determined to reduce the transmembrane pressure increase by 18% when utilized alone, and by 49% when used in combination with citric acid. The combined treatment was more effective compared with the citric acid treatment alone, which reported ca. 30% transmembrane pressure reduction. Collectively, the findings demonstrated that bacteriophages can be used as a biocidal agent to mitigate undesirable P. aeruginosa-associated problems in seawater applications. PMID:29770130

[Susceptibility and resistence of Pseudomonas aeruginosa to antimicrobial agents].

PubMed

Gamero Delgado, M C; García-Mayorgas, A D; Rodríguez, F; Ibarra, A; Casal, M

2007-06-01

Pseudomonas aeruginosa is an opportunistic microorganism that is frequently the cause of nosocomial infections. Multiple mechanisms are involved in its natural and acquired resistance to many of the antimicrobial agents commonly used in clinical practice. The objective of this study was to assess the susceptibility and resistance patterns of P. aeruginosa strains isolated in Hospital Reina Sofia between 2000 and 2005, as well as to analyze the differences between intrahospital and extrahospital isolates in 2005 and to compare the results with those obtained in other studies. A total of 3,019 strains of P. aeruginosa from different hospitals and nonhospital settings were evaluated, taking into consideration their degree of sensitivity to different antibiotics. The MICs were determined by means of the Wider I automated system (Soria Melguizo), taking into consideration the criteria of susceptibility and resistance recommended by MENSURA. Results of the analysis showed that P. aeruginosa maintained similar levels of antimicrobial susceptibility during the period 2000-2005, with increased susceptibility to amikacin, gentamicin and tobramycin. There were also important differences in the degree of susceptibility between intrahospital and extrahospital strains, except for imipenem and fosfomycin. The intrahospital difference in susceptibility was also evaluated, emphasizing the importance of periodically studying susceptibility and resistance patterns of P. aeruginosa in each setting in order to evaluate different therapeutic guidelines, as it is not always advisable to extrapolate data from different regions. These differences can be explained by the different use of antibiotics in each center and the geographic variations of the resistance mechanisms of P. aeruginosa.

Molecular epidemiology of Pseudomonas aeruginosa.

PubMed

Speert, David P

2002-10-01

Pseudomonas aeruginosa is a serious opportunistic pathogen in certain compromised hosts, such as those with cystic fibrosis, thermal burns and cancer. It also causes less severe noninvasive disease, such as otitis externa and hot tub folliculitis, in normal hosts. P. aeruginosa is phenotypically very unstable, particularly in patients with chronic infection. Phenotypic typing techniques are useful for understanding the epidemiology of acute infections, but they are limited by their discriminatory power and by their inability to group isolates that are phenotypically unrelated but genetically homologous. Molecular typing techniques, developed over the past decade, are highly discriminatory and are useful for typing strains from patients with chronic infection where the bacterial phenotype is unstable; this is particularly true in cystic fibrosis, where patients often are infected with the same strain for several decades, but the bacteria undergo phenotypic alteration. Molecular typing techniques, which have proven useful in typing P. aeruginosa for epidemiological purposes, include pulsed field gel electrophoresis, restriction fragment length polymorphic DNA analysis, random amplified polymorphic DNA analysis, repetitive extrapalindromic PCR analysis, and multilocus sequence typing. These methods are generally only available in specialized laboratories, but they should be used when data from phenotypic typing analysis are ambiguous or when phenotypic methods are unreliable, such as in cystic fibrosis.

Intestinal contents of a late Pleistocene mastodont from midcontinental north America

NASA Astrophysics Data System (ADS)

Lepper, Bradley T.; Frolking, Tod A.; Fisher, Daniel C.; Goldstein, Gerald; Sanger, Jon E.; Wymer, Dee Anne; Ogden, J. Gordon; Hooge, Paul E.

1991-07-01

Salvage excavations of a nearly complete and remarkably well-preserved skeleton of an American mastodont ( Mammut americanum) in Licking County, Ohio, yielded a discrete, cylindrical mass of plant material found in association with articulated vertebrae and associated ribs. This material is interpreted as intestinal contents of the mastodont and paleobotanical analyses indicate that the mastodont diet included significant amounts of low, herbaceous vegetation. Enteric bacteria ( Enterobacter cloacae), isolated from a sample of this material, are believed to represent survivors or descendants of the intestinal microflora of the mastodont. This is the first report of the isolation of bacteria associated with late Pleistocene megafauna.

Spread of Plasmids Carrying Multiple GES Variants

PubMed Central

Cuzon, Gaelle; Bogaerts, Pierre; Bauraing, Caroline; Huang, Te-Din; Glupczynski, Youri

2016-01-01

Five GES-producing Enterobacteriaceae isolates that displayed an extended-spectrum β-lactamase (ESBL) phenotype harbored two GES variants: GES-7 ESBL and GES-6 carbapenemase. In all isolates, the two GES alleles were located on the same integron that was inserted into an 80-kb IncM1 self-conjugative plasmid. Whole-genome sequencing suggested in vivo horizontal gene transfer of the plasmid along with clonal diffusion of Enterobacter cloacae. To our knowledge, this is the first description in Europe of clustered Enterobacteriaceae isolates carrying two GES β-lactamases, of which one has extended activity toward carbapenems. PMID:27216071

[In vitro indirect pathogenesis of Pseudomonas aeruginosa against anti MRSA chemotherapy].

PubMed

Satoh, Naotake; Kondo, Shigemi; Yamada, Toshihiko; Saionji, Katsu; Oguri, Toyoko; Igari, Jun

2004-09-01

In the patient with a chronic respiratory disease, both Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA) are frequently detected from expectoration. Vancomycin (VCM) and arbekacin (ABK) are both recommended for the chemotherapy of MRSA infection in Japan. Minocycline (MINO) is also selected for the treatment of MRSA infection. While rifampicin (RFP) and a trimetoprim-sulfamethoxazole combination (ST) are also recommended in Europe and USA but not recommended in Japan for the chemotherapy of MRSA infection. It is pointed out that coexistence bacteria affect chemotherapy as an indirect pathogen. Not only an antibacterial action but the immunological action or the metabolic effect against chronic P. aeruginosa infection such as DPB is known by the administration of 14-membered ring macrolides including erythromycin (EM). We considered the influence of P. aeruginosa isolated with MRSA on the activity against anti-MRSA agents by the disk diffusion method with bilayer flat agar in vitro. Moreover, we also examined the influence of EM against the activity of the anti-MRSA agents when P. aeruginosa was coexistence. One strain of MRSA as an indicator strain and 100 strains of P. aeruginosa as test strains, which were obtained from clinical materials, were used for the following experiment. P. aeruginosa was streaked on to the Mueller-Hinton agar culture medium (MHA), and they incubated at 35 degrees C for 24 hours. Then, the blood agar plate was piled up, MRSA was streaked on the blood agar surface, the susceptibility test disks (VCM, ABK, MINO, RFP, ST) were put on it, and incubated at 35 degrees C for a further 24 hours. The diameter of the zone of inhibition around the susceptibility disks against MRSA was measured and compared with P. aeruginosa free experiments. The anti-MRSA activity of MINO, ST and ABK was reduced by coexistence of P. aeruginosa. In RFP and VCM, the anti-MRSA activity was reinforced by coexistence of P. aeruginosa

Activity of Imipenem with Relebactam against Gram-Negative Pathogens from New York City

PubMed Central

Lapuebla, Amabel; Abdallah, Marie; Olafisoye, Olawole; Cortes, Christopher; Urban, Carl; Landman, David

2015-01-01

Imipenem with relebactam was active against Escherichia coli, Klebsiella pneumoniae, and Enterobacter spp., including K. pneumoniae carbapenemase (KPC)-producing isolates. Loss of OmpK36 in KPC-producing K. pneumoniae isolates affected the susceptibility of this combination. Enhanced activity was evident against Pseudomonas aeruginosa, including isolates with depressed oprD and increased ampC expression. However, the addition of relebactam to imipenem did not provide added benefit against Acinetobacter baumannii. The combination of imipenem with relebactam demonstrated activity against KPC-producing Enterobacteriaceae and multidrug-resistant P. aeruginosa. PMID:26014931

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.

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.

Acute ileitis facilitates infection with multidrug resistant Pseudomonas aeruginosa in human microbiota-associated mice.

PubMed

von Klitzing, Eliane; Ekmekciu, Ira; Bereswill, Stefan; Heimesaat, Markus M

2017-01-01

The rising incidence of multidrug resistant (MDR) Gram-negative bacteria including Pseudomonas aeruginosa has become a serious issue in prevention of its spread particularly among hospitalized patients. It is, however, unclear whether distinct conditions such as acute intestinal inflammation facilitate P. aeruginosa infection of vertebrate hosts. To address this, we analysed P. aeruginosa infection in human microbiota-associated (hma) mice with acute ileitis induced by peroral Toxoplasma gondii challenge. When perorally infected with P. aeruginosa at day 3 post ileitis induction, hma mice displayed higher intestinal P. aeruginosa loads as compared to hma mice without ileitis. However, the overall intestinal microbiota composition was not disturbed by P. aeruginosa (except for lowered bifidobacterial populations), and the infection did not further enhance ileal immune cell responses. Pro-inflammatory cytokines including IFN-γ and IL-12p70 were similarly increased in ileum and mesenteric lymph nodes of P. aeruginosa infected and uninfected hma mice with ileitis. The anti-inflammatory cytokine IL-10 increased multifold upon ileitis induction, but interestingly more distinctly in P. aeruginosa infected as compared to uninfected controls. Immune responses were not restricted to the intestines as indicated by elevated pro-inflammatory cytokine levels in liver and kidney upon ileitis induction. However, except for hepatic TNF-α levels, P. aeruginosa infection did not result in more distinct pro-inflammatory cytokine secretion in liver and kidney of hma mice with ileitis. Whereas viable intestinal bacteria were more frequently detected in systemic compartments such as spleen and cardiac blood of P. aeruginosa infected than uninfected mice at day 7 following ileitis induction, P. aeruginosa infection did not exacerbate systemic pro-inflammatory sequelae, but resulted in lower IL-10 serum levels. Acute intestinal inflammation facilitates infection of the vertebrate host

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.

[Nosocomial infection caused by Pseudomonas aeruginosa in intensive care unit].

PubMed

Wu, Yu-Qi; Shan, Hong-Wei; Zhao, Xian-Yu; Yang, Xing-Yi

2011-02-01

To investigate the risk factors of nosocomial infection caused by Pseudomonas aeruginosa in intensive care unit (ICU), in order to provide reference for an effective measure of infection control. A retrospective study of cases of Pseudomonas aeruginosa infection occurring in ICU was made with multivariable Logistic regression analysis. The clinical data of 1 950 cases admitted from January 2002 to December 2006 were found to have nosocomial infection caused by Pseudomonas aeruginosa were analyzed in order to identify its independent risk factors. Sixty-four out of 1 950 patients were found to suffer from nosocomial infection caused by Pseudomonas aeruginosa, the morbidity rate was 3.3%. At the same time, and in the same department, 37 patients suffering from infection caused by Escherichia coli, served as control group. Univariate analysis showed that the risk factors for nosocomial infection caused by Pseudomonas aeruginosa were the use of corticosteroid, unconsciousness or craniocerebral trauma, abdominal surgery, thorax/abdomen drainage tube, mechanical ventilation, and tracheostomy [the use of corticosteroid: odds ratio (OR)=3.364, 95% confidence interval (95%CI) 1.445-7.830; unconsciousness or craniocerebral trauma: OR=4.026, 95%CI 1.545-10.490; abdominal surgery: OR=0.166, 95%CI 0.068-0.403; thorax/abdomen drainage tube: OR=0.350, 95%CI 0.150-0.818; tracheostomy: OR=4.095, 95%CI 1.638-10.740]. Multivariate analysis showed that the independent risk factors of nosocomial infection caused by Pseudomonas aeruginosa in ICU were: the use of corticosteroid and mechanical ventilation [the use of corticosteroid: OR=3.143, 95%CI 1.115-8.856; mechanical ventilation: OR=3.195, 95%CI 1.607-6.353, P<0.05 and P<0.01]. The independent risk factors of nosocomial infection caused by Pseudomonas aeruginosa in ICU are the use of corticosteroid and mechanical ventilation. Measures should be taken to take care of the risk factors in order to prevent nosocomial infection caused by

PAMDB: a comprehensive Pseudomonas aeruginosa metabolome database.

PubMed

Huang, Weiliang; Brewer, Luke K; Jones, Jace W; Nguyen, Angela T; Marcu, Ana; Wishart, David S; Oglesby-Sherrouse, Amanda G; Kane, Maureen A; Wilks, Angela

2018-01-04

The Pseudomonas aeruginosaMetabolome Database (PAMDB, http://pseudomonas.umaryland.edu) is a searchable, richly annotated metabolite database specific to P. aeruginosa. P. aeruginosa is a soil organism and significant opportunistic pathogen that adapts to its environment through a versatile energy metabolism network. Furthermore, P. aeruginosa is a model organism for the study of biofilm formation, quorum sensing, and bioremediation processes, each of which are dependent on unique pathways and metabolites. The PAMDB is modelled on the Escherichia coli (ECMDB), yeast (YMDB) and human (HMDB) metabolome databases and contains >4370 metabolites and 938 pathways with links to over 1260 genes and proteins. The database information was compiled from electronic databases, journal articles and mass spectrometry (MS) metabolomic data obtained in our laboratories. For each metabolite entered, we provide detailed compound descriptions, names and synonyms, structural and physiochemical information, nuclear magnetic resonance (NMR) and MS spectra, enzymes and pathway information, as well as gene and protein sequences. The database allows extensive searching via chemical names, structure and molecular weight, together with gene, protein and pathway relationships. The PAMBD and its future iterations will provide a valuable resource to biologists, natural product chemists and clinicians in identifying active compounds, potential biomarkers and clinical diagnostics. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Managing Pseudomonas aeruginosa respiratory infections in cystic fibrosis.

PubMed

Langan, Katherine M; Kotsimbos, Tom; Peleg, Anton Y

2015-12-01

The current guidelines and recent clinical research in the management of Pseudomonas aeruginosa respiratory infections in cystic fibrosis (CF) are reviewed. Areas where further research is required will also be highlighted. P. aeruginosa is a key respiratory pathogen in CF. Inhaled tobramycin or colistin is recommended for early eradication to prevent establishment of chronic infection. Other antibiotic options are currently being investigated. The long-term success of eradication strategies is also now being assessed. The use of inhaled antibiotics in the management of chronic P. aeruginosa infection is an area of active investigation. Acute pulmonary exacerbations are still a major cause of morbidity and mortality. Guidelines continue to recommend combination intravenous therapy but further research is required to clarify the advantage of this approach. Multidrug resistance is common and potentially more effective antipseudomonal antibiotics may soon become available. The management of P. aeruginosa respiratory infection in CF remains a challenging area, especially in the setting of multidrug resistance. The role of inhaled antibiotics continues to be expanded. Further research is required in the key areas of eradication and management of chronic infection and acute pulmonary exacerbations to identify those treatments that optimize long-term, clinical benefits.

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.

Quorum-sensing inhibition abrogates the deleterious impact of Pseudomonas aeruginosa on airway epithelial repair.

PubMed

Ruffin, Manon; Bilodeau, Claudia; Maillé, Émilie; LaFayette, Shantelle L; McKay, Geoffrey A; Trinh, Nguyen Thu Ngan; Beaudoin, Trevor; Desrosiers, Martin-Yvon; Rousseau, Simon; Nguyen, Dao; Brochiero, Emmanuelle

2016-09-01

Chronic Pseudomonas aeruginosa lung infections are associated with progressive epithelial damage and lung function decline. In addition to its role in tissue injury, the persistent presence of P. aeruginosa-secreted products may also affect epithelial repair ability, raising the need for new antivirulence therapies. The purpose of our study was to better understand the outcomes of P. aeruginosa exoproducts exposure on airway epithelial repair processes to identify a strategy to counteract their deleterious effect. We found that P. aeruginosa exoproducts significantly decreased wound healing, migration, and proliferation rates, and impaired the ability of directional migration of primary non-cystic fibrosis (CF) human airway epithelial cells. Impact of exoproducts was inhibited after mutations in P. aeruginosa genes that encoded for the quorum-sensing (QS) transcriptional regulator, LasR, and the elastase, LasB, whereas impact was restored by LasB induction in ΔlasR mutants. P. aeruginosa purified elastase also induced a significant decrease in non-CF epithelial repair, whereas protease inhibition with phosphoramidon prevented the effect of P. aeruginosa exoproducts. Furthermore, treatment of P. aeruginosa cultures with 4-hydroxy-2,5-dimethyl-3(2H)-furanone, a QS inhibitor, abrogated the negative impact of P. aeruginosa exoproducts on airway epithelial repair. Finally, we confirmed our findings in human airway epithelial cells from patients with CF, a disease featuring P. aeruginosa chronic respiratory infection. These data demonstrate that secreted proteases under the control of the LasR QS system impair airway epithelial repair and that QS inhibitors could be of benefit to counteract the deleterious effect of P. aeruginosa in infected patients.-Ruffin, M., Bilodeau, C., Maillé, É., LaFayette, S. L., McKay, G. A., Trinh, N. T. N., Beaudoin, T., Desrosiers, M.-Y., Rousseau, S., Nguyen, D., Brochiero, E. Quorum-sensing inhibition abrogates the deleterious impact

A Carbon-Neutral Photosynthetic Microbial Fuel Cell Powered by Microcystis aeruginosa.

PubMed

Ma, Meirong; Cao, Limin; Chen, Li; Ying, Xiaofang; Deng, Zongwu

2015-07-01

A photosynthetic microbial fuel cell (m-PMFC) is developed for generating electricity by harnessing solar energy using Microcystis aeruginosa. In this m-PMFC, commensal bacteria can consume the nutrients that Microcystis aeruginosa produces to generate electricity so that no net CO₂production occurs. A b-MFC is constructed to confirm the role of commensal bacteria in electric generation. An s-PMFC is constructed to confirm the contribution of Microcystis aeruginosa as substrates. The power outputs of m-PMFCs exhibit no significant difference in terms of different inoculation amount of Microcystis aeruginosa or light/dark cycles. The power density of m-PMFC exhibits similar response to bubbling of N₂and O₂as that of b-MFC, as confirmed by cyclic voltammetry analysis of m-PMFC and b-MFC. Scanning electron microscope images demonstrate that the biofilm of m-PMFC consists mainly of commensal bacteria. These results suggest that commensal bacteria act as the main biocatalysts and Microcystis aeruginosa as the anode substrates in the m-PMFC.

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.

Pseudomonas aeruginosa Lifestyle: A Paradigm for Adaptation, Survival, and Persistence

PubMed Central

Moradali, M. Fata; Ghods, Shirin; Rehm, Bernd H. A.

2017-01-01

Pseudomonas aeruginosa is an opportunistic pathogen affecting immunocompromised patients. It is known as the leading cause of morbidity and mortality in cystic fibrosis (CF) patients and as one of the leading causes of nosocomial infections. Due to a range of mechanisms for adaptation, survival and resistance to multiple classes of antibiotics, infections by P. aeruginosa strains can be life-threatening and it is emerging worldwide as public health threat. This review highlights the diversity of mechanisms by which P. aeruginosa promotes its survival and persistence in various environments and particularly at different stages of pathogenesis. We will review the importance and complexity of regulatory networks and genotypic-phenotypic variations known as adaptive radiation by which P. aeruginosa adjusts physiological processes for adaptation and survival in response to environmental cues and stresses. Accordingly, we will review the central regulatory role of quorum sensing and signaling systems by nucleotide-based second messengers resulting in different lifestyles of P. aeruginosa. Furthermore, various regulatory proteins will be discussed which form a plethora of controlling systems acting at transcriptional level for timely expression of genes enabling rapid responses to external stimuli and unfavorable conditions. Antibiotic resistance is a natural trait for P. aeruginosa and multiple mechanisms underlying different forms of antibiotic resistance will be discussed here. The importance of each mechanism in conferring resistance to various antipseudomonal antibiotics and their prevalence in clinical strains will be described. The underlying principles for acquiring resistance leading pan-drug resistant strains will be summarized. A future outlook emphasizes the need for collaborative international multidisciplinary efforts to translate current knowledge into strategies to prevent and treat P. aeruginosa infections while reducing the rate of antibiotic resistance

Effect of novel antibacterial gallium-carboxymethyl cellulose on Pseudomonas aeruginosa.

PubMed

Valappil, Sabeel P; Yiu, Humphrey H P; Bouffier, Laurent; Hope, Christopher K; Evans, Gary; Claridge, John B; Higham, Susan M; Rosseinsky, Matthew J

2013-02-07

Gallium has emerged as a new therapeutic agent due partly to the scarcity in development of new antibiotics. In this study, a novel antibacterial gallium exchanged carboxymethyl cellulose (Ga-CMC) has been developed and tested for the susceptibility on a common bacteria, Pseudomonas aeruginosa. The results show that an increase in average molecular weight (MW) from 90 k, 250 k to 700 k of Ga-CMC caused a decrease in antimicrobial activity against planktonic P. aeruginosa. Gallium loading of the Ga-CMC (250 k) samples was altered by varying the amount of functionality (0.7, 0.9 and 1.2 acid groups per mole of carbohydrate) which affected also its antimicrobial activity against planktonic P. aeruginosa. Further, the ability to prevent the growth of biofilms of P. aeruginosa was tested on MW = 250 k samples with 0.9 acid groups per mole of carbohydrate as this sample showed the most promising activity against planktonic P. aeruginosa. Gallium was found to reduce biofilm growth of P. aeruginosa with a maximum effect (0.85 log(10) CFU reduction compared to sodium-carboxymethyl cellulose, Na-CMC) after 24 h. Results of the solubility and ion exchange studies show that this compound is suitable for the controlled release of Ga(3+) upon their breakdown in the presence of bacteria. SEM EDX analysis confirmed that Ga(3+) ions are evenly exchanged on the cellulose surface and systematic controls were carried out to ensure that antibacterial activity is solely due to the presence of gallium as samples intrinsic acidity or nature of counterion did not affect the activity. The results presented here highlight that Ga-CMC may be useful in controlled drug delivery applications, to deliver gallium ions in order to prevent infections due to P. aeruginosa biofilms.

Inhibition of Pseudomonas aeruginosa biofilm formation by 2,2'-bipyridyl, lipoic, kojic and picolinic acids.

PubMed

Çevik, Kübra; Ulusoy, Seyhan

2015-08-01

The inhibitory effects of iron chelators, and FeCl3 chelation on biofilm formation and swarming motility were investigated against an opportunistic human pathogen Pseudomonas aeruginosa. The inhibitory activity of 2,2'-bipyridyl, lipoic acid, kojic acid and picolinic acid on biofilm formation of P. aeruginosa strain PAO1 and three clinical isolates (P. aeruginosa PAK01, P. aeruginosa PAK02 and P. aeruginosa PAK03) were investigated, based on crystal violet assay, and swarming motility test. The kojic, lipoic and picolinic acid inhibited biofilm formation by 5-33% in all tested P. aeruginosa isolates. When chelated iron was added, biofilm inhibition rates were determined to be 39-57%. Among the tested chelators against P. aeruginosa, lipoic acid (84%) and kojic acid (68%) presented the highest inhibition of swarming motility. This is the first study to report the inhibitory effect of lipoic acid on biofilm formation and swarming motility of P. aeruginosa. It is considered that lipoic and picolinic acids can serve as alternatives for the treatment of the P. aeruginosa infections by inhibiting biofilm formation.

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

Establishing the diagnosis of chronic colonization with Pseudomonas aeruginosa of cystic fibrosis patients: Comparison of the European consensus criteria with genotyping of P. aeruginosa isolates.

PubMed

Jonckheere, Leander; Schelstraete, Petra; Van Simaey, Leen; Van Braeckel, Eva; Willekens, Julie; Van Daele, Sabine; De Baets, Frans; Vaneechoutte, Mario

2018-04-11

After antibiotic eradication treatment for a first ever Pseudomonas aeruginosa isolation, the European consensus criteria (ECC) are widely used to assess colonization status with P. aeruginosa in CF-patients. We evaluated to what extent genotyping (GT) of subsequent P. aeruginosa isolates could predict/assess chronic colonization (CC), in comparison with the ECC. Over a 14-year period, sputa were cultured from 80 CF-patients (age range: 2-51 years), from a first ever isolation of P. aeruginosa onwards. Patients with a positive culture for P. aeruginosa received antibiotic eradication treatment. For the 40 patients for whom three or more P. aeruginosa isolates were available, these isolates were genotyped. According to the ECC, 27 out of the 40 patients (67.5%) became CC during the study period (ECC-positive patients). Genotyping confirmed persistence of the same genotype for 25 of these ECC-positive patients. Genotyping indicated persistence of the same genotype for at least two subsequent isolates for 5 out of 13 ECC-negative patients. Culture-positivity characteristics of the 27 ECC-positive patients corresponded well to those of the 30 GT-positive patients, with an overall higher number of positive cultures as well as a shorter interval in between first and second isolate compared to ECC-negative and GT-negative patients. Genotyping indicated persistence of the same genotype on average 9.3 months earlier than CC according to the ECC (P < 0.01). Genotyping of P. aeruginosa isolates confirmed CC for 25 out of 27 ECC-positive patients (92.6% specificity) and predicted CC 9.3 months earlier than the ECC. Copyright © 2018 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

The Effect of Strict Segregation on Pseudomonas aeruginosa in Cystic Fibrosis Patients

PubMed Central

van Mansfeld, Rosa; de Vrankrijker, Angelica; Brimicombe, Roland; Heijerman, Harry; Teding van Berkhout, Ferdinand; Spitoni, Cristian; Grave, Sanne; van der Ent, Cornelis; Wolfs, Tom; Willems, Rob; Bonten, Marc

2016-01-01

Introduction Segregation of patients with cystic fibrosis (CF) was implemented to prevent chronic infection with epidemic Pseudomonas aeruginosa strains with presumed detrimental clinical effects, but its effectiveness has not been carefully evaluated. Methods The effect of strict segregation on the incidence of P. aeruginosa infection in CF patients was investigated through longitudinal protocolized follow-up of respiratory tract infection before and after segregation. In two nested cross-sectional studies in 2007 and 2011 the P. aeruginosa population structure was investigated and clinical parameters were determined in patients with and without infection with the Dutch epidemic P. aeruginosa clone (ST406). Results Of 784 included patients 315 and 382 were at risk for acquiring chronic P. aeruginosa infection before and after segregation. Acquisition rates were, respectively, 0.14 and 0.05 per 1,000 days at risk (HR: 0.66, 95% CI [0.2548–1.541]; p = 0.28). An exploratory subgroup analysis indicated lower acquisition after segregation in children < 15 years of age (HR: 0.43, 95% CI[0.21–0.95]; p = 0.04). P. aeruginosa population structure did not change after segregation and ST406 was not associated with lung function decline, death or lung transplantation. Conclusions Strict segregation was not associated with a statistically significant lower acquisition of chronic P. aeruginosa infection and ST406 was not associated with adverse clinical outcome. After segregation there were no new acquisitions of ST406. In an unplanned exploratory analysis chronic acquisition of P. aeruginosa was lower after implementation of segregation in patients under 15 years of age. PMID:27280467

Pseudomonas aeruginosa isolates in severe chronic obstructive pulmonary disease: characterization and risk factors

PubMed Central

2014-01-01

Background Patients with severe chronic obstructive pulmonary disease (COPD) are at increased risk of infection by P. aeruginosa. The specific role of bronchiectasis in both infection and chronic colonization by this microorganism in COPD, however, remains ill defined. To evaluate the prevalence and risk factors for P. aeruginosa recovery from sputum in outpatients with severe COPD, characterizing P. aeruginosa isolates by pulsed-field gel electrophoresis (PFGE) and focusing on the influence of bronchiectasis on chronic colonization in these patients. Methods A case-cohort study of 118 patients with severe COPD attended at a Respiratory Day Unit for an acute infectious exacerbation and followed up over one year. High-resolution CT scans were performed during stability for bronchiectasis assessment and sputum cultures were obtained during exacerbation and stability in all patients. P. aeruginosa isolates were genotyped by PFGE. Determinants of the recovery of P. aeruginosa in sputum and chronic colonization by this microorganism were assessed by multivariate analysis. Results P. aeruginosa was isolated from 41 of the 118 patients studied (34.7%). Five of these 41 patients (12.2%) with P. aeruginosa recovery fulfilled criteria for chronic colonization. In the multivariate analysis, the extent of bronchiectasis (OR 9.8, 95% CI: 1.7 to 54.8) and the number of antibiotic courses (OR 1.7, 95% CI: 1.1 to 2.5) were independently associated with an increased risk of P. aeruginosa isolation. Chronic colonization was unrelated to the presence of bronchiectasis (p=0.75). In patients with chronic colonization the isolates of P. aeruginosa retrieved corresponded to the same clones during the follow-up, and most of the multidrug resistant isolates (19/21) were harbored by these patients. Conclusions The main risk factors for P. aeruginosa isolation in severe COPD were the extent of bronchiectasis and exposure to antibiotics. Over 10% of these patients fulfilled criteria for

Current State of Resistance to Antibiotics of Last-Resort in South Africa: A Review from a Public Health Perspective

PubMed Central

Osei Sekyere, John

2016-01-01

A review of the literature was undertaken to delineate the current level and mechanisms of resistance to carbapenems, colistin, and tigecycline in South Africa. Thirty-two English publications and 32 National Institute of Communicable Diseases communiqués identified between early January 2000 and 20 May, 2016 showed substantial reports of NDM (n = 860), OXA-48 (n = 584), VIM (n = 131), and IMP (n = 45) carbapenemases within this period, mainly in Klebsiella pneumoniae (n = 1138), Acinetobacter baumannii (n = 332), Enterobacter cloacae (n = 201), and Serratia marcescens (n = 108). Colistin and tigecycline resistance was prevalent among K. pneumoniae, A. baumannii, S. marcescens, and E. cloacae. The first mcr-1 colistin resistance gene to be detected in South Africa was reported in Escherichia coli from livestock as well as from hospitalized and outpatients. There are increasing reports of NDM and OXA-48 carbapenemases among Enterobacteriaceae and A. baumannii in South Africa. Mcr-1 is now present in South African patients and livestock. Resistance to carbapenems, colistin, and tigecycline restricts infection management options for clinicians. PMID:27747206

Leukoerythroblastosis in a Young Child with Severe Malaria and Superimposed Gram Negative Infection.

PubMed

Varo, Rosauro; Sitoe, Antonio; Cossa, Anelsio; Ordi, Jaume; Rozman, Maria; Bassat, Quique

2017-12-18

Leukoerythroblastosis, a non-specific and often short-lasting response of the bone marrow to different diseases such as malignancies or infections, is characterized by the presence in the peripheral blood of immature red and white cells. We present a case of leukoerythoblastosis occurring in a 24 months old Mozambican girl, in the context of a severe malaria episode and an associated urinary tract infection. Peripheral blood smear was used for diagnosis of malaria and leukoerythroblastosis. Enterobacter cloacae isolation and antibiotic susceptibility testing were performed by conventional microbiology. Peripheral blood smear was positive for Plasmodium falciparum and showed a leukoerythroblastosis with red cell anisopoikilocytosis and left shifted neutrophils. Urine culture confirmed the presence of a multi-resistant E. cloacae. Treatment of underlying conditions resolved the leukoerythroblastic reaction. Leukoerythroblastosis may be related to different infectious diseases and may also appear in the context of severe malaria. Bacterial superinfection needs to be investigated. © The Author(s) [2017]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Reduction of virulence factor pyocyanin production in multidrug-resistant Pseudomonas aeruginosa.

PubMed

Fuse, Katsuhiro; Fujimura, Shigeru; Kikuchi, Toshiaki; Gomi, Kazunori; Iida, Yasuhiro; Nukiwa, Toshihiro; Watanabe, Akira

2013-02-01

Nosocomial infections caused by metallo-β-lactamase (MBL)-producing multidrug-resistant (MDR) Pseudomonas aeruginosa have become a worldwide problem. Pyocyanin, a representative pigment produced by P. aeruginosa, is the major virulence factor of this organismThe aim of this study was to investigate the pyocyanin-producing ability of MBL-producing MDR P. aeruginosa. A total of 50 clinical isolates of P. aeruginosa, including 20 MDR strains, were collected at 18 general hospitals in Japan. The chromaticity and luminosity produced by pyocyanin in each isolate were measured. The quantity of pyocyanin and the expression of the phzM and phzS genes coding a pyocyanin synthesis enzyme were measured. MDR strains showed a bright yellow-green, while non-MDR strains tended to show a dark blue-green. The quantities of pyocyanin in MBL-producing strains and non-producing strains were 0.015 ± 0.002 and 0.41 ± 0.10 μg, respectively. The expression of the phzM and phzS genes in the MDR strains was 11 and 14 %, respectively, of the expression in the non-MDR strains. When the MBL gene was transduced into P. aeruginosa and it acquired multidrug resistance, it was shown that the pyocyanin-producing ability decreased. The pathogenicity of MBL-producing MDR P. aeruginosa may be lower than that of non-MDR strains. These MBL-producing MDR strains may be less pathogenic than non-MDR strains. This may explain why MDR-P. aeruginosa is unlikely to cause infection but, rather, causes subclinical colonization only.

Candida albicans Inhibits Pseudomonas aeruginosa Virulence through Suppression of Pyochelin and Pyoverdine Biosynthesis

PubMed Central

Lopez-Medina, Eduardo; Fan, Di; Coughlin, Laura A.; Ho, Evi X.; Lamont, Iain L.; Reimmann, Cornelia; Hooper, Lora V.; Koh, Andrew Y.

2015-01-01

Bacterial-fungal interactions have important physiologic and medical ramifications, but the mechanisms of these interactions are poorly understood. The gut is host to trillions of microorganisms, and bacterial-fungal interactions are likely to be important. Using a neutropenic mouse model of microbial gastrointestinal colonization and dissemination, we show that the fungus Candida albicans inhibits the virulence of the bacterium Pseudomonas aeruginosa by inhibiting P. aeruginosa pyochelin and pyoverdine gene expression, which plays a critical role in iron acquisition and virulence. Accordingly, deletion of both P. aeruginosa pyochelin and pyoverdine genes attenuates P. aeruginosa virulence. Heat-killed C. albicans has no effect on P. aeruginosa, whereas C. albicans secreted proteins directly suppress P. aeruginosa pyoverdine and pyochelin expression and inhibit P. aeruginosa virulence in mice. Interestingly, suppression or deletion of pyochelin and pyoverdine genes has no effect on P. aeruginosa’s ability to colonize the GI tract but does decrease P. aeruginosa’s cytotoxic effect on cultured colonocytes. Finally, oral iron supplementation restores P. aeruginosa virulence in P. aeruginosa and C. albicans colonized mice. Together, our findings provide insight into how a bacterial-fungal interaction can modulate bacterial virulence in the intestine. Previously described bacterial-fungal antagonistic interactions have focused on growth inhibition or colonization inhibition/modulation, yet here we describe a novel observation of fungal-inhibition of bacterial effectors critical for virulence but not important for colonization. These findings validate the use of a mammalian model system to explore the complexities of polymicrobial, polykingdom infections in order to identify new therapeutic targets for preventing microbial disease. PMID:26313907

Pseudomonas aeruginosa keratitis: outcomes and response to corticosteroid treatment.

PubMed

Sy, Aileen; Srinivasan, Muthiah; Mascarenhas, Jeena; Lalitha, Prajna; Rajaraman, Revathi; Ravindran, Meenakshi; Oldenburg, Catherine E; Ray, Kathryn J; Glidden, David; Zegans, Michael E; McLeod, Stephen D; Lietman, Thomas M; Acharya, Nisha R

2012-01-25

To compare the clinical course and effect of adjunctive corticosteroid therapy in Pseudomonas aeruginosa with those of all other strains of bacterial keratitis. Subanalyses were performed on data collected in the Steroids for Corneal Ulcers Trial (SCUT), a large randomized controlled trial in which patients were treated with moxifloxacin and were randomly assigned to 1 of 2 adjunctive treatment arms: corticosteroid or placebo (4 times a day with subsequent reduction). Multivariate analysis was used to determine the effect of predictors, organism, and treatment on outcomes, 3-month best-spectacle-corrected visual acuity (BSCVA), and infiltrate/scar size. The incidence of adverse events over a 3-month follow-up period was compared using Fisher's exact test. SCUT enrolled 500 patients. One hundred ten patients had P. aeruginosa ulcers; 99 of 110 (90%) enrolled patients returned for follow-up at 3 months. Patients with P. aeruginosa ulcers had significantly worse visual acuities than patients with other bacterial ulcers (P = 0.001) but showed significantly more improvement in 3-month BSCVA than those with other bacterial ulcers, adjusting for baseline characteristics (-0.14 logMAR; 95% confidence interval, -0.23 to -0.04; P = 0.004). There was no significant difference in adverse events between P. aeruginosa and other bacterial ulcers. There were no significant differences in BSCVA (P = 0.69), infiltrate/scar size (P = 0.17), and incidence of adverse events between patients with P. aeruginosa ulcers treated with adjunctive corticosteroids and patients given placebo. Although P. aeruginosa corneal ulcers have a more severe presentation, they appear to respond better to treatment than other bacterial ulcers. The authors did not find a significant benefit with corticosteroid treatment, but they also did not find any increase in adverse events. (ClinicalTrials.gov number, NCT00324168.).

Pseudomonas aeruginosa Keratitis: Outcomes and Response to Corticosteroid Treatment

PubMed Central

Sy, Aileen; Srinivasan, Muthiah; Mascarenhas, Jeena; Lalitha, Prajna; Rajaraman, Revathi; Ravindran, Meenakshi; Oldenburg, Catherine E.; Ray, Kathryn J.; Glidden, David; Zegans, Michael E.; McLeod, Stephen D.; Lietman, Thomas M.

2012-01-01

Purpose. To compare the clinical course and effect of adjunctive corticosteroid therapy in Pseudomonas aeruginosa with those of all other strains of bacterial keratitis. Methods. Subanalyses were performed on data collected in the Steroids for Corneal Ulcers Trial (SCUT), a large randomized controlled trial in which patients were treated with moxifloxacin and were randomly assigned to 1 of 2 adjunctive treatment arms: corticosteroid or placebo (4 times a day with subsequent reduction). Multivariate analysis was used to determine the effect of predictors, organism, and treatment on outcomes, 3-month best-spectacle-corrected visual acuity (BSCVA), and infiltrate/scar size. The incidence of adverse events over a 3-month follow-up period was compared using Fisher's exact test. Results. SCUT enrolled 500 patients. One hundred ten patients had P. aeruginosa ulcers; 99 of 110 (90%) enrolled patients returned for follow-up at 3 months. Patients with P. aeruginosa ulcers had significantly worse visual acuities than patients with other bacterial ulcers (P = 0.001) but showed significantly more improvement in 3-month BSCVA than those with other bacterial ulcers, adjusting for baseline characteristics (−0.14 logMAR; 95% confidence interval, −0.23 to −0.04; P = 0.004). There was no significant difference in adverse events between P. aeruginosa and other bacterial ulcers. There were no significant differences in BSCVA (P = 0.69), infiltrate/scar size (P = 0.17), and incidence of adverse events between patients with P. aeruginosa ulcers treated with adjunctive corticosteroids and patients given placebo. Conclusions. Although P. aeruginosa corneal ulcers have a more severe presentation, they appear to respond better to treatment than other bacterial ulcers. The authors did not find a significant benefit with corticosteroid treatment, but they also did not find any increase in adverse events. (ClinicalTrials.gov number, NCT00324168.) PMID:22159005

Bispecific antibody targets multiple Pseudomonas aeruginosa evasion mechanisms in the lung vasculature.

PubMed

Thanabalasuriar, Ajitha; Surewaard, Bas Gj; Willson, Michelle E; Neupane, Arpan S; Stover, Charles K; Warrener, Paul; Wilson, George; Keller, Ashley E; Sellman, Bret R; DiGiandomenico, Antonio; Kubes, Paul

2017-06-01

Pseudomonas aeruginosa is a major cause of severe infections that lead to bacteremia and high patient mortality. P. aeruginosa has evolved numerous evasion and subversion mechanisms that work in concert to overcome immune recognition and effector functions in hospitalized and immunosuppressed individuals. Here, we have used multilaser spinning-disk intravital microscopy to monitor the blood-borne stage in a murine bacteremic model of P. aeruginosa infection. P. aeruginosa adhered avidly to lung vasculature, where patrolling neutrophils and other immune cells were virtually blind to the pathogen's presence. This cloaking phenomenon was attributed to expression of Psl exopolysaccharide. Although an anti-Psl mAb activated complement and enhanced neutrophil recognition of P. aeruginosa, neutrophil-mediated clearance of the pathogen was suboptimal owing to a second subversion mechanism, namely the type 3 secretion (T3S) injectisome. Indeed, T3S prevented phagosome acidification and resisted killing inside these compartments. Antibody-mediated inhibition of the T3S protein PcrV did not enhance bacterial phagocytosis but did enhance killing of the few bacteria ingested by neutrophils. A bispecific mAb targeting both Psl and PcrV enhanced neutrophil uptake of P. aeruginosa and also greatly increased inhibition of T3S function, allowing for phagosome acidification and bacterial killing. These data highlight the need to block multiple evasion and subversion mechanisms in tandem to kill P. aeruginosa.

Flavobacterium cloacae sp. nov., isolated from waste water.

PubMed

Liu, Hongming; Lu, Peng; Zhu, Guoping

2017-04-01

A Gram-stain-negative, non-spore-forming, rod-shaped, non-motile bacterium, named wh15T, was isolated from the waste water of a municipal wastewater treatment plant in Wuhu, PR China. The taxonomic status of the strain was characterized using a polyphasic taxonomic approach. Growth occurred at 15-45 °C (optimum, 25-40 °C), at pH 5.0-8.0 (optimum, pH 7.0) and with 0-4 % NaCl (optimum, 1-2 %). Phylogenetic analyses based on 16S rRNA gene sequences revealed that wh15T represented a member of genus Flavobacterium and shared the highest similarity with Flavobacterium ummariense DS-12T (93.93 %), Flavobacterium ceti 454-2T (93.71 %) and Flavobacterium marinum SW105T (93.63 %). The major respiratory quinone of wh15T was MK-6 and major fatty acids were iso-C15 : 0, iso-C15 : 0 3-OH, iso-C17 : 0 3-OH, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and summed feature 9 (iso-C17 : 1ω9c and/or C16 : 0 10-methyl). The DNA G+C content of wh15T was 32.3 mol%. Phenotypic, phylogenetic and chemotaxonomic evidence indicated that wh15T represents a novel species of the genus Flavobacterium, the name Flavobacterium cloacae is proposed. The type strain is wh15T (=CCTCC AB 2015420T=JCM 31173T).

Isolation of an iron-binding compound from Pseudomonas aeruginosa.

PubMed Central

Cox, C D; Graham, R

1979-01-01

An iron-binding compound was isolated from ethyl acetate extracts of culture supernatant fluids of Pseudomonas aeruginosa and was purified by successive paper and thin-layer chromatographic procedures. The purified compound was characterized by UV, visible, infrared, and fluorescence spectroscopy. The compound possesses phenolic characteristics, with little or no similarity to dihydroxybenzoates and no indication of a hydroxamate group. P. aeruginosa synthesized the compound during active growth in culture media containing less than 5 X 10(-6) M added FeCl3. When added to iron-poor cultures of P. aeruginosa, the compound promoted the growth of the bacterium and also reversed growth inhibition by the iron chelator ethylenediamine-di-(o-hydroxyphenylacetic acid). PMID:104968

Application of distilled white vinegar in the cloaca to counter the increase in Campylobacter numbers on broiler skin during feather removal.

PubMed

Berrang, M E; Smith, D P; Hinton, A

2006-02-01

Because of the escape of highly contaminated gut contents from the cloaca of positive carcasses, Campylobacter numbers recovered from broiler carcass skin samples increase during automated feather removal. Vinegar is known to have antimicrobial action. The objective of this study was to determine the effect of vinegar placed in the cloaca prior to feather removal on the numbers of Campylobacter recovered from broiler breast skin. Broilers were stunned, killed, and bled in a pilot processing plant. Vinegar was placed in the colons of the chickens prior to scalding. Carcasses were scalded, and Campylobacter numbers were determined on breast skin before and after passage through a commercial-style feather-picking machine. Campylobacter numbers recovered from the breast skin of untreated control carcasses increased during feather removal from 1.3 log CFU per sample prior to defeathering to 4.2 log afterward. Placement of water in the colon before scalding had no effect on Campylobacter numbers. Campylobacter numbers recovered from the breast skin of carcasses treated with vinegar also increased during defeathering but to a significantly lesser extent. Treated carcasses experienced only a 1-log increase from 1.6 log CFU per sample before feather removal to 2.6 log CFU per sample afterward. Application of an effective food-grade antimicrobial in the colon prior to scald can limit the increase in Campylobacter contamination of broiler carcasses during defeathering.

Activation of the lectin pathway of complement in experimental human keratitis with Pseudomonas aeruginosa.

PubMed

Osthoff, Michael; Brown, Karl D; Kong, David C M; Daniell, Mark; Eisen, Damon P

2014-01-01

Pseudomonas aeruginosa (P. aeruginosa) microbial keratitis (MK) is a sight-threatening disease. Previous animal studies have identified an important contribution of the complement system to the clearance of P. aeruginosa infection of the cornea. Mannose-binding lectin (MBL), a pattern recognition receptor of the lectin pathway of complement, has been implicated in the host defense against P. aeruginosa. However, studies addressing the role of the lectin pathway in P. aeruginosa MK are lacking. Hence, we sought to determine the activity of the lectin pathway in human MK caused by P. aeruginosa. Primary human corneal epithelial cells (HCECs) from cadaveric donors were exposed to two different P. aeruginosa strains. Gene expression of interleukin (IL)-6, IL-8, MBL, and other complement proteins was determined by reverse transcription-polymerase chain reaction (RT-PCR) and MBL synthesis by enzyme-linked immunosorbent assay and intracellular flow cytometry. MBL gene expression was not detected in unchallenged HCECs. Exposure of HCECs to P. aeruginosa resulted in rapid induction of the transcriptional expression of MBL, IL-6, and IL-8. In addition, expression of several complement proteins of the classical and lectin pathways, but not the alternative pathway, were upregulated after 5 h of challenge, including MBL-associated serine protease 1. However, MBL protein secretion was not detectable 18 h after challenge with P. aeruginosa. MK due to P. aeruginosa triggers activation of MBL and the lectin pathway of complement. However, the physiologic relevance of this finding is unclear, as corresponding MBL oligomer production was not observed.

Activation of the lectin pathway of complement in experimental human keratitis with Pseudomonas aeruginosa

PubMed Central

Osthoff, Michael; Brown, Karl D.; Kong, David C.M.; Daniell, Mark

2014-01-01

Purpose Pseudomonas aeruginosa (P. aeruginosa) microbial keratitis (MK) is a sight-threatening disease. Previous animal studies have identified an important contribution of the complement system to the clearance of P. aeruginosa infection of the cornea. Mannose-binding lectin (MBL), a pattern recognition receptor of the lectin pathway of complement, has been implicated in the host defense against P. aeruginosa. However, studies addressing the role of the lectin pathway in P. aeruginosa MK are lacking. Hence, we sought to determine the activity of the lectin pathway in human MK caused by P. aeruginosa. Methods Primary human corneal epithelial cells (HCECs) from cadaveric donors were exposed to two different P. aeruginosa strains. Gene expression of interleukin (IL)-6, IL-8, MBL, and other complement proteins was determined by reverse transcription-polymerase chain reaction (RT–PCR) and MBL synthesis by enzyme-linked immunosorbent assay and intracellular flow cytometry. Results MBL gene expression was not detected in unchallenged HCECs. Exposure of HCECs to P. aeruginosa resulted in rapid induction of the transcriptional expression of MBL, IL-6, and IL-8. In addition, expression of several complement proteins of the classical and lectin pathways, but not the alternative pathway, were upregulated after 5 h of challenge, including MBL-associated serine protease 1. However, MBL protein secretion was not detectable 18 h after challenge with P. aeruginosa. Conclusions MK due to P. aeruginosa triggers activation of MBL and the lectin pathway of complement. However, the physiologic relevance of this finding is unclear, as corresponding MBL oligomer production was not observed. PMID:24426774

Physiological effects of the herbicide glyphosate on the cyanobacterium Microcystis aeruginosa.

PubMed

Wu, Liang; Qiu, Zhihao; Zhou, Ya; Du, Yuping; Liu, Chaonan; Ye, Jing; Hu, Xiaojun

2016-09-01

Glyphosate has been used extensively for weed control in agriculture in many countries. However, glyphosate can be transported into the aquatic environment and might cause adverse effects on aquatic life. This study investigated the physiological characteristics of cyanobacteria Microcystis aeruginosa (M. aeruginosa) after exposure to glyphosate, and the results showed that changes in cell density production, chlorophyll a and protein content are consistent. In M. aeruginosa, oxidative stress caused by glyphosate indicated that 48h of exposure increased the concentration of malondialdehyde (MDA) and enhanced the activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD). To further investigate the toxicity of glyphosate on M. aeruginosa, the viability of treated cells was monitored and the toxin release was determined. The results indicated that glyphosate induced apoptosis of and triggered toxin release in M. aeruginosa. These results are helpful for understanding the toxic effects of glyphosate on cyanobacteria, which is important for environmental assessment and protection. These results are also useful for guidance on the application of this type of herbicide in agricultural settings. Copyright © 2016 Elsevier B.V. All rights reserved.

Inhibition of Biofilm Formation by Esomeprazole in Pseudomonas aeruginosa and Staphylococcus aureus

PubMed Central

Singh, Vandana; Arora, Vaneet; Alam, M. Jahangir

2012-01-01

Staphylococcus aureus and Pseudomonas aeruginosa are common nosocomial pathogens responsible for biofilm-associated infections. Proton pump inhibitors (PPI), such as esomeprazole, may have novel antimicrobial properties. The objective of this study was to assess whether esomeprazole prevents sessile bacterial growth and biofilm formation and whether it may have synergistic killing effects with standard antibiotics. The antibiofilm activity of esomeprazole at 0.25 mM was tested against two strains each of S. aureus and P. aeruginosa. Bacterial biofilms were prepared using a commercially available 96-peg-plate Calgary biofilm device. Sessile bacterial CFU counts and biomass were assessed during 72 hours of esomeprazole exposure. The killing activities after an additional 24 hours of vancomycin (against S. aureus) and meropenem (against P. aeruginosa) treatment with or without preexposure to esomeprazole were also assessed by CFU and biomass analyses. P. aeruginosa and S. aureus strains exposed to esomeprazole displayed decreased sessile bacterial growth and biomass (P < 0.001, each parameter). After 72 h of exposure, there was a 1-log10 decrease in the CFU/ml of esomeprazole-exposed P. aeruginosa and S. aureus strains compared to controls (P < 0.001). After 72 h of exposure, measured absorbance was 100% greater in P. aeruginosa control strains than in esomeprazole-exposed strains (P < 0.001). Increased killing and decreased biomass were observed for esomeprazole-treated bacteria compared to untreated controls exposed to conventional antibiotics (P < 0.001, each parameter). Reduced biofilm growth after 24 h was visibly apparent by light micrographs for P. aeruginosa and S. aureus isolates exposed to esomeprazole compared to untreated controls. In conclusion, esomeprazole demonstrated an antibiofilm effect against biofilm-producing S. aureus and P. aeruginosa. PMID:22664967

A network biology approach to denitrification in Pseudomonas aeruginosa

DOE PAGES

Arat, Seda; Bullerjahn, George S.; Laubenbacher, Reinhard

2015-02-23

Pseudomonas aeruginosa is a metabolically flexible member of the Gammaproteobacteria. Under anaerobic conditions and the presence of nitrate, P. aeruginosa can perform (complete) denitrification, a respiratory process of dissimilatory nitrate reduction to nitrogen gas via nitrite (NO₂), nitric oxide (NO) and nitrous oxide (N₂O). This study focuses on understanding the influence of environmental conditions on bacterial denitrification performance, using a mathematical model of a metabolic network in P. aeruginosa. To our knowledge, this is the first mathematical model of denitrification for this bacterium. Analysis of the long-term behavior of the network under changing concentration levels of oxygen (O₂), nitrate (NO₃),more » and phosphate (PO₄) suggests that PO₄ concentration strongly affects denitrification performance. The model provides three predictions on denitrification activity of P. aeruginosa under various environmental conditions, and these predictions are either experimentally validated or supported by pertinent biological literature. One motivation for this study is to capture the effect of PO₄ on a denitrification metabolic network of P. aeruginosa in order to shed light on mechanisms for greenhouse gas N₂O accumulation during seasonal oxygen depletion in aquatic environments such as Lake Erie (Laurentian Great Lakes, USA). Simulating the microbial production of greenhouse gases in anaerobic aquatic systems such as Lake Erie allows a deeper understanding of the contributing environmental effects that will inform studies on, and remediation strategies for, other hypoxic sites worldwide.« less

Arsenate biotransformation by Microcystis aeruginosa under different nitrogen and phosphorus levels.

PubMed

Che, Feifei; Du, Miaomiao; Yan, Changzhou

2018-04-01

The arsenate (As(V)) biotransformation by Microcystis aeruginosa in a medium with different concentrations of nitrogen (N) and phosphorus (P) has been studied under laboratory conditions. When 15μg/L As(V) was added, N and P in the medium showed effective regulation on arsenic (As) metabolism in M. aeruginosa, resulting in significant differences in the algal growth among different N and P treatments. Under 0.2mg/L P treatment, increases in N concentration (4-20mg/L) significantly stimulated the cell growth and therefore indirectly enhanced the production of dimethylarsinic acid (DMA), the main As metabolite, accounting for 71%-79% of the total As in the medium. Meanwhile, 10-20mg/L N treatments accelerated the ability of As metabolization by M. aeruginosa, leading to higher contents of DMA per cell. However, As(V) uptake by M. aeruginosa was significantly impeded by 0.5-1.0mg/L P treatment, resulting in smaller rates of As transformation in M. aeruginosa as well as lower contents of As metabolites in the medium. Our data demonstrated that As(V) transformation by M. aeruginosa was significantly accelerated by increasing N levels, while it was inhibited by increasing P levels. Overall, both P and N play key roles in As(V) biotransformation processes. Copyright © 2017. Published by Elsevier B.V.

Pseudomonas aeruginosa uses T3SS to inhibit diabetic wound healing

PubMed Central

Goldufsky, Josef; Wood, Stephen J.; Jayaraman, Vijayakumar; Majdobeh, Omar; Chen, Lin; Qin, Shanshan; Zhang, Chunxiang; DiPietro, Luisa A.; Shafikhani, Sasha H.

2015-01-01

Diabetic foot ulcers are responsible for more hospitalizations than any other complication of diabetes. Bacterial infection is recognized as an important factor associated with impaired healing in diabetic ulcers. Pseudomonas aeruginosa is the most frequently detected Gram-negative pathogen in diabetic ulcers. P. aeruginosa infection has been shown to impair healing in diabetic wounds in a manner that correlates with its ability to form biofilm. While the majority of infections in diabetic ulcers are biofilm associated, 33% of infections are nonbiofilm in nature. P. aeruginosa is the most prevalent Gram-negative pathogen in all diabetic wound types, which suggests that the deleterious impact of P. aeruginosa on healing in diabetic wounds goes beyond its ability to form biofilm and likely involves other factors. The Type III Secretion System (T3SS) virulence structure is required for the pathogenesis of all P. aeruginosa clinical isolates, suggesting that it may also play a role in the inhibition of wound repair in diabetic skin ulcers. We evaluated the role of T3SS in mediating P. aeruginosa–induced tissue damage in the wounds of diabetic mice. Our data demonstrate that P. aeruginosa establishes a robust and persistent infection in diabetic wounds independent of its ability to form biofilm and causes severe wound damage in a manner that primarily depends on its T3SS. PMID:25912785

Metallo-Beta-Lactamase Producing Pseudomonas aeruginosa in a Healthcare Setting in Alexandria, Egypt.

PubMed

Abaza, Amani F; El Shazly, Soraya A; Selim, Heba S A; Aly, Gehan S A

2017-09-27

Pseudomonas aeruginosa has emerged as a major healthcare associated pathogen that creates a serious public health disaster in both developing and developed countries. In this work we aimed at studying the occurrence of metallo-beta-lactamase (MBL) producing P. aeruginosa in a healthcare setting in Alexandria, Egypt. This cross sectional study included 1583 clinical samples that were collected from patients admitted to Alexandria University Students' Hospital. P. aeruginosa isolates were identified using standard microbiological methods and were tested for their antimicrobial susceptibility patterns using single disc diffusion method according to the Clinical and Laboratory Standards Institute recommendations. Thirty P. aeruginosa isolates were randomly selected and tested for their MBL production by both phenotypic and genotypic methods. Diagnostic Epsilometer test was done to detect metallo-beta-lactamase enzyme producers and polymerase chain reaction test was done to detect imipenemase (IMP), Verona integron-encoded (VIM) and Sao Paulo metallo-beta-lactamase (IMP) encoding genes. Of the 1583 clinical samples, 175 (11.3%) P. aeruginosa isolates were identified. All the 30 (100%) selected P. aeruginosa isolates that were tested for MBL production by Epsilometer test were found to be positive; where 19 (63.3%) revealed blaSPM gene and 11 (36.7%) had blaIMP gene. blaVIM gene was not detected in any of the tested isolates. Isolates of MBL producing P. aeruginosa were highly susceptible to polymyxin B 26 (86.7%) and highly resistant to amikacin 26 (86.7%). MBL producers were detected phenotypically by Epsilometer test in both carbapenem susceptible and resistant P. aeruginosa isolates. blaSPM was the most commonly detected MBL gene in P. aeruginosa isolates.

Effects of sulfate on microcystin production, photosynthesis, and oxidative stress in Microcystis aeruginosa.

PubMed

Chen, Lei; Gin, Karina Y H; He, Yiliang

2016-02-01

Increasing sulfate in freshwater systems, caused by human activities and climate change, may have negative effects on aquatic organisms. Microcystis aeruginosa (M. aeruginosa) is both a major primary producer and a common toxic cyanobacterium, playing an important role in the aquatic environment. This study first investigated the effects of sulfate on M. aeruginosa. The experiment presented here aims at analyzing the effects of sulfate on physiological indices, molecular levels, and its influencing mechanism. The results of our experiment showed that sulfate (at 40, 80, and 300 mg L(-1)) inhibited M. aeruginosa growth, increased both intracellular and extracellular toxin contents, and enhanced the mcyD transcript level. Sulfate inhibited the photosynthesis of M. aeruginosa, based on the decrease in pigment content and the down-regulation of photosynthesis-related genes after sulfate exposure. Furthermore, sulfate decreased the maximum electron transport rate, causing the cell to accumulate surplus electrons and form reactive oxygen species (ROS). Sulfate also increased the malondialdehyde (MDA) content, which showed that sulfate damaged the cytomembrane. This damage contributed to the release of intracellular toxin to the culture medium. Although sulfate increased superoxide dismutase (SOD) activities, expression of sod, and total antioxidant capacity in M. aeruginosa, it still overwhelmed the antioxidant system since the ROS level simultaneously increased, and finally caused oxidative stress. Our results indicate that sulfate has direct effects on M. aeruginosa, inhibits photosynthesis, causes oxidative stress, increases toxin production, and affects the related genes expression in M. aeruginosa.

Antimicrobial activity and chemical composition of Brunfelsia uniflora flower oleoresin extracted by supercritical carbon dioxide.

PubMed

Thiesen, L C T; Sugauara, E Y Y; Tešević, V; Glamočlija, J; Soković, M; Gonçalves, J E; Gazim, Z C; Linde, G A; Colauto, N B

2017-04-13

Brunfelsia genus is traditionally utilized in popular medicine due to its antibacterial and antifungal properties to name but a few. However, studies on the antimicrobial activity of Brunfelsia uniflora flower oleoresin have not been found yet. This study aimed to evaluate the chemical composition and antimicrobial activity of B. uniflora flower oleoresin obtained by supercritical carbon dioxide. Oleoresin from the plant dried flowers was obtained by carbon dioxide, and the chemical composition was analyzed by gas chromatographic-mass spectrometry. The minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and minimum fungicidal concentration (MFC) of this oleoresin for seven bacteria and eight fungi were determined using 96-well microtiter plates. The oleoresin MBC for Bacillus cereus, Enterobacter cloacae, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella enterica, and Staphylococcus aureus ranged from 0.01 to 0.08 mg/mL, whereas the controls streptomycin and ampicillin varied from 0.1 and 0.5 mg/mL. The oleoresin MFC for Aspergillus fumigatus, Aspergillus niger, Aspergillus ochraceus, Aspergillus versicolor, Penicillium funiculosum, Penicillium ochrochloron, Penicillium verrucosum var. cyclopium, and Trichoderma viride varied from 0.01 to 0.08 mg/mL, whereas the controls bifonazole and ketoconazole ranged from 0.2 to 3.5 mg/mL. The oleoresin obtained by supercritical carbon dioxide presented bacteriostatic, bactericidal, fungistatic, and fungicidal activities that were higher than the positive controls streptomycin, ampicillin, bifonazole, and ketoconazole. The high antimicrobial activity was related to the high content of (E, E)-geranyllinalool that composes 21.0% of the oleoresin and a possible synergic action with fatty acid esters that made up 50.5% of the oleoresin. The oleoresin antimicrobial activity against common multiresistant bacteria in severe infectious processes as P. aeruginosa or against toxin

In vitro antibacterial and antitumor activities of some medicinal plant extracts, growing in Turkey.

PubMed

Yildirim, Arzu Birinci; Karakas, Fatma Pehlivan; Turker, Arzu Ucar

2013-08-01

To investigate antibacterial and antitumor activities of 51 different extracts prepared with 3 types of solvents (water, ethanol and methanol) of 16 different plant species (Ajuga reptans (A. reptans) L., Phlomis pungens (P. pungens) Willd., Marrubium astracanicum (M. astracanicum) Jacq., Nepeta nuda (N. nuda) L., Stachys annua (S. annua) L., Genista lydia (G. lydia) Boiss., Nuphar lutea (N. lutea) L., Nymphaea alba (N. alba) L., Vinca minor (V. minor) L., Stellaria media (S. media) L., Capsella bursa-pastoris (C. bursa-pastoris) L., Galium spurium (G. spurium) L., Onosma heterophyllum (O. heterophyllum) Griseb., Reseda luteola (R. luteola) L., Viburnum lantana (V. lantana) L. and Mercurialis annua (M. annua) L.) grown in Turkey was conducted. Antibacterial activity was evaluated with 10 bacteria including Streptococcus pyogenes (S. pyogenes), Staphylococcus aureus (S. aureus), Staphylococcus epidermidis (S. epidermidis), Escheria coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), Salmonella typhimurium (S. typhimurium), Serratia marcescens (S. marcescens), Proteus vulgaris (P. vulgaris), Enterobacter cloacae (E. cloacea), and Klebsiella pneumoniae (K. pneumoniae) by using disc diffusion method. Antitumor activity was evaluated with Agrobacterium tumefaciens (A. tumefaciens)-induced potato disc tumor assay. Best antibacterial activity was obtained with ethanolic extract of P. pungens against S. pyogenes. Ethanolic and methanolic extract of N. alba and ethanolic extract of G. lydia also showed strong antibacterial activities. Results indicated that alcoholic extracts especially ethanolic extracts exhibited strong antibacterial activity against both gram-positive and gram-negative bacteria. Best antitumor activity was obtained with methanolic extracts of N. alba and V. lantana (100% tumor inhibition). Ethanolic extract of N. alba, alcoholic extracts of N. lutea, A. reptans and V. minor flowers, methanolic extracts of G. lydia and O. heterophyllum and ethanolic

Biodegradation of Endocrine-Disrupting Chemicals and Residual Organic Pollutants of Pulp and Paper Mill Effluent by Biostimulation.

PubMed

Chandra, Ram; Sharma, Pooja; Yadav, Sangeeta; Tripathi, Sonam

2018-01-01

Effluent discharged from the pulp and paper industry contains various refractory and androgenic compounds, even after secondary treatment by activated processes. Detailed knowledge is not yet available regarding the properties of organic pollutants and methods for their bioremediation. This study focused on detecting residual organic pollutants of pulp and paper mill effluent after biological treatment and assessing their degradability by biostimulation. The major compounds identified in the effluent were 2,3,6-trimethylphenol, 2-methoxyphenol (guaiacol), 2,6-dimethoxyphenol (syringol), methoxycinnamic acid, pentadecane, octadecanoic acid, trimethylsilyl ester, cyclotetracosane, 5,8-dimethoxy-6-methyl-2,4-bis(phenylmethyl)napthalen-1-ol, and 1,2-benzendicarboxylic acid diisononyl ester. Most of these compounds are classified as endocrine-disrupting chemicals and environmental toxicants. Some compounds are lignin monomers that are metabolic products from secondary treatment of the discharged effluent. This indicated that the existing industrial process could not further degrade the effluent. Supplementation by carbon (glucose 1.0%) and nitrogen (peptone 0.5%) bio-stimulated the degradation process. The degraded sample after biostimulation showed either disappearance or generation of metabolic products under optimized conditions, i.e., a stirring rate of 150 rpm and temperature of 37 ± 1°C after 3 and 6 days of bacterial incubation. Isolated potential autochthonous bacteria were identified as Klebsiella pneumoniae IITRCP04 (KU715839), Enterobacter cloacae strain IITRCP11 (KU715840), Enterobacter cloacae IITRCP14 (KU715841), and Acinetobacter pittii strain IITRCP19 (KU715842). Lactic acid, benzoic acid, and vanillin, resulting from residual chlorolignin compounds, were generated as potential value-added products during the detoxification of effluent in the biostimulation process, supporting the commercial importance of this process.

Epidemiologic and Genotypic Review of Carbapenemase-Producing Organisms in British Columbia, Canada, between 2008 and 2014

PubMed Central

Sekirov, Inna; Croxen, Matthew A.; Ng, Corrinne; Azana, Robert; Chang, Yin; Mataseje, Laura; Boyd, David; Mangat, Chand; Mack, Benjamin; Tadros, Manal; Brodkin, Elizabeth; Kibsey, Pamela; Stefanovic, Aleksandra; Champagne, Sylvie; Mulvey, Michael R.

2015-01-01

Carbapenemase-producing organisms (CPOs) are a serious emerging problem for health care facilities worldwide. Owing to their resistance to most antimicrobial therapies, CPOs are difficult to treat and pose a challenge for infection prevention and control. Since 2010, lab-based surveillance for CPOs and PCR-based testing were implemented in British Columbia (BC), Canada. A review of CPOs in BC from 2008 to March 2014 was done to characterize the resistance mechanisms and possible clonal strain transmission and to compare pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and plasmid restriction fragment length polymorphism (RFLP) as molecular typing tools. During this study period, a total of 177 CPO cases were identified. Patient demographics and travel history were reviewed, and a descriptive analysis was carried out. PFGE profiles, MLST, and plasmid RFLP analysis for a subset of Escherichia coli, Klebsiella pneumoniae, and Enterobacter species isolates were obtained and analyzed. Our findings demonstrate that CPOs have been increasing in number in BC over time, from 1 isolate/year retrospectively identified in 2008 and 2009 to 82 isolates in 2013 and 30 isolates in the first quarter of 2014. Overall, K. pneumoniae isolates lack clonality, although some seemingly related clusters have been found. Plasmid analysis showed evidence of the spread of plasmids carrying carbapenemase-encoding genes between the examined isolates. Analysis of Enterobacter cloacae isolates revealed a more clonal nature of these CPOs in BC. The presence of related clusters provides evidence of interpatient organism transmission both within and between institutions. Although in our study, NDM-harboring E. cloacae isolates appeared to spread clonally, the spread of carbapenem resistance in K. pneumoniae seems to be plasmid mediated. PMID:26607987

Toxicogenomic response of Pseudomonas aeruginosa to ortho-phenylphenol

PubMed Central

Nde, Chantal W; Jang, Hyeung-Jin; Toghrol, Freshteh; Bentley, William E

2008-01-01

Background Pseudomonas aeruginosa (P. aeruginosa) is the most common opportunistic pathogen implicated in nosocomial infections and in chronic lung infections in cystic fibrosis patients. Ortho-phenylphenol (OPP) is an antimicrobial agent used as an active ingredient in several EPA registered disinfectants. Despite its widespread use, there is a paucity of information on its target molecular pathways and the cellular responses that it elucidates in bacteria in general and in P. aeruginosa in particular. An understanding of the OPP-driven gene regulation and cellular response it elicits will facilitate more effective utilization of this antimicrobial and possibly lead to the development of more effective disinfectant treatments. Results Herein, we performed a genome-wide transcriptome analysis of the cellular responses of P. aeruginosa exposed to 0.82 mM OPP for 20 and 60 minutes. Our data indicated that OPP upregulated the transcription of genes encoding ribosomal, virulence and membrane transport proteins after both treatment times. After 20 minutes of exposure to 0.82 mM OPP, genes involved in the exhibition of swarming motility and anaerobic respiration were upregulated. After 60 minutes of OPP treatment, the transcription of genes involved in amino acid and lipopolysaccharide biosynthesis were upregulated. Further, the transcription of the ribosome modulation factor (rmf) and an alternative sigma factor (rpoS) of RNA polymerase were downregulated after both treatment times. Conclusion Results from this study indicate that after 20 minutes of exposure to OPP, genes that have been linked to the exhibition of anaerobic respiration and swarming motility were upregulated. This study also suggests that the downregulation of the rmf and rpoS genes may be indicative of the mechanism by which OPP causes decreases in cell viability in P. aeruginosa. Consequently, a protective response involving the upregulation of translation leading to the increased synthesis of

[Antiseptic sensitivity of clinical strains of Pseudomonas aeruginosa].

PubMed

Adarchenko, A A; Krasil'nikov, A P; Sobeshchuk, O P

1989-12-01

MICs, the frequency of clinical and statistic resistance and the antiseptic activity index were studied in complex on out-of-hospital and hospital ecovars of P. aeruginosa. The forms resistant to a number of antiseptics, i.e. chloramine B, chlorhexidine, decamethoxine and dioxidine whose frequency eventually increased were shown to be widely distributed. The antiseptic sensitivity spectrum was more narrow and more heterogeneous than that of other bacteria, the heterogeneity level being dependent on the antiseptic type and bacterial ecovar. The activity of pervomur, phenol, resorcin and boric acid was higher against the clinical strains of P. aeruginosa while iodopyrin, sulfacetamide sodium and dioxidine were less active. The P. aeruginosa strains had natural resistance to cetylpyridinium chloride, rokkal, ethonium, sodium laurate and laurylsulfate and rivanol. It was recommended to assay antiseptic sensitivity of agents causing purulent inflammatory infections and to control circulation of antiseptic resistant variants of bacteria in hospitals.

Activity of Imipenem with Relebactam against Gram-Negative Pathogens from New York City.

PubMed

Lapuebla, Amabel; Abdallah, Marie; Olafisoye, Olawole; Cortes, Christopher; Urban, Carl; Landman, David; Quale, John

2015-08-01

Imipenem with relebactam was active against Escherichia coli, Klebsiella pneumoniae, and Enterobacter spp., including K. pneumoniae carbapenemase (KPC)-producing isolates. Loss of OmpK36 in KPC-producing K. pneumoniae isolates affected the susceptibility of this combination. Enhanced activity was evident against Pseudomonas aeruginosa, including isolates with depressed oprD and increased ampC expression. However, the addition of relebactam to imipenem did not provide added benefit against Acinetobacter baumannii. The combination of imipenem with relebactam demonstrated activity against KPC-producing Enterobacteriaceae and multidrug-resistant P. aeruginosa. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

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.

RAPD- and ERIC-Based Typing of Clinical and Environmental Pseudomonas aeruginosa Isolates.

PubMed

Auda, Ibtesam Ghadban; Al-Kadmy, Israa M S; Kareem, Sawsan Mohammed; Lafta, Aliaa Khyuon; A'Affus, Mustafa Hussein Obeid; Khit, Ibrahim Abd Aloahd; Al Kheraif, Abdulaziz Abdullah; Divakar, Darshan Devang; Ramakrishnaiah, Ravikumar

2017-03-01

Pseudomonas aeruginosa is a major cause of nosocomial infection in children and adults, resulting in significant morbidity and mortality due to its ability to acquire drug resistance. The ability of P. aeruginosa in the environment to cause infection in individuals has been reported previously; henceforth, surveillance of the emergence and transmission of P. aeruginosa strains among patients is important for infection control in a clinical setup. Various gene-typing methods have been used for epidemiological typing of P. aeruginosa isolates for the purpose of surveillance. In this work, the suitability and comparability of two typing methods, enterobacterial repetitive intergenic consensus (ERIC)-PCR and random amplification of polymorphic DNA (RAPD)-PCR fingerprinting, were studied to characterize P. aeruginosa strains isolated from clinical and environmental sources. Forty-four clinical and environmental bacterial isolates of P. aeruginosa were collected between October 2015 and January 2016. DNA extraction, ERIC-PCR and RAPD-PCR, agarose gel electrophoresis, and phylogenetic analyses were carried using the unweighted pair-group method with mean. RAPD typing revealed less clonality among clinical isolates, whereas the ERIC method showed greater similarity in comparison with RAPD. Environmental isolates, however, showed greater similarity using RAPD compared with ERIC typing. With only a few exceptions, most clinical isolates were distinct from environmental isolates, irrespective of the typing method. In conclusion, both the RAPD and ERIC typing methods proved to be good tools in understanding clonal diversity. The results also suggest that there is no relationship between clinical and environmental isolates. The absence of clonality among the clinical isolates may indicate that most P. aeruginosa infection cases could be endemic and not epidemic and that endemic infections may be due to nonclonal strains of P. aeruginosa.

Enterobactin-mediated iron transport in Pseudomonas aeruginosa.

PubMed Central

Poole, K; Young, L; Neshat, S

1990-01-01

A pyoverdine-deficient strain of Pseudomonas aeruginosa was unable to grow in an iron-deficient minimal medium in the presence of the nonmetabolizable iron chelator ethylene diamine-di(omega-hydroxyphenol acetic acid) (EDDHA), although addition of enterobactin to EDDHA-containing minimal media did restore growth of the pyoverdine-deficient P. aeruginosa. Consistent with the apparent ability of enterobactin to provide iron to P. aeruginosa, enterobactin-dependent 55Fe3+ uptake was observed in cells of P. aeruginosa previously grown in an iron-deficient medium containing enterobactin (or enterobactin-containing Escherichia coli culture supernatant). This uptake was energy dependent, was observable at low concentrations (60 nM) of FeCl3, and was absent in cells cultured without enterobactin. A novel protein with a molecular weight of approximately 80,000 was identified in the outer membranes of cells grown in iron-deficient minimal medium containing enterobactin, concomitant with the induction of enterobactin-dependent iron uptake. A Tn501 insertion mutant lacking this protein was isolated and shown to be deficient in enterobactin-mediated iron transport at 60 nM FeCl3, although it still exhibited enterobactin-dependent growth in iron-deficient medium containing EDDHA. It was subsequently observed that the mutant was, however, capable of enterobactin-mediated iron transport at much higher concentrations (600 nM) of FeCl3. Indeed, enterobactin-dependent iron uptake at this concentration of iron was observed in both the mutant and parent strains irrespective of whether they had been cultured in the presence of enterobactin.(ABSTRACT TRUNCATED AT 250 WORDS) Images PMID:2174865

Occurrence of Pseudomonas aeruginosa in waters: implications for patients with cystic fibrosis (CF).

PubMed

Caskey, S; Stirling, J; Moore, J E; Rendall, J C

2018-06-01

Chronic Pseudomonas aeruginosa infection is associated with increased morbidity and mortality in patients with cystic fibrosis (CF). Current understanding of risk factors for acquisition is limited and so the aim of this study was to examine a large sample of environmental waters from diverse sources. Environmental water samples (n = 7904) from jacuzzis, hydrants, swimming pools, hot tubs, plunge pools, bottled natural mineral water, taps, springs, ice machines, water coolers, bores and showers were examined for the presence of P. aeruginosa. Pseudomonas aeruginosa was detected in 524/7904 (6·6%) waters examined. Hot tubs (51/243; 20·9%), tap water (3/40; 8%) and jacuzzis (432/5811; 7·4%) were the most likely environments where P. aeruginosa was isolated. Pseudomonas aeruginosa was isolated from bottled water (2/67; 3%). Our study highlights the ubiquitous nature of P. aeruginosa in the environment. Given CF patients are frequently counselled to make lifestyle changes to minimize P. aeruginosa exposure, these results have important implications. In particular, the occurrence of P. aeruginosa in tap water highlights the need to disinfect the CF patients' nebulizer after each use. This study examined a large number of water sources (n = 7904) over a 9-year period for the presence of Pseudomonas aeruginosa. The study highlighted that jacuzzis (n = 5811; 7% positive) and hot tubs had the highest occurrence of this organism (n = 243, 21% positive). Patients with cystic fibrosis (CF) are interested in knowing what water environments are likely to be contaminated with this organism, as this bacterium is an important cause of increased morbidity and mortality in such patients. With such information, CF patients and parents may make informed decisions about lifestyle choice and water environment avoidance. © 2018 The Society for Applied Microbiology.

Dose-response algorithms for water-borne Pseudomonas aeruginosa folliculitis.

PubMed

Roser, D J; Van Den Akker, B; Boase, S; Haas, C N; Ashbolt, N J; Rice, S A

2015-05-01

We developed two dose-response algorithms for P. aeruginosa pool folliculitis using bacterial and lesion density estimates, associated with undetectable, significant, and almost certain folliculitis. Literature data were fitted to Furumoto & Mickey's equations, developed for plant epidermis-invading pathogens: N l = A ln(1 + BC) (log-linear model); P inf = 1-e(-r c C) (exponential model), where A and B are 2.51644 × 107 lesions/m2 and 2.28011 × 10-11 c.f.u./ml P. aeruginosa, respectively; C = pathogen density (c.f.u./ml), N l = folliculitis lesions/m2, P inf = probability of infection, and r C = 4·3 × 10-7 c.f.u./ml P. aeruginosa. Outbreak data indicates these algorithms apply to exposure durations of 41 ± 25 min. Typical water quality benchmarks (≈10-2 c.f.u./ml) appear conservative but still useful as the literature indicated repeated detection likely implies unstable control barriers and bacterial bloom potential. In future, culture-based outbreak testing should be supplemented with quantitative polymerase chain reaction and organic carbon assays, and quantification of folliculitis aetiology to better understand P. aeruginosa risks.

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.

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.

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.

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.

Molecular Characterization of OXA-198 Carbapenemase-Producing Pseudomonas aeruginosa Clinical Isolates.

PubMed

Bonnin, Rémy A; Bogaerts, Pierre; Girlich, Delphine; Huang, Te-Din; Dortet, Laurent; Glupczynski, Youri; Naas, Thierry

2018-06-01

Carbapenemase-producing Pseudomonadaceae have increasingly been reported worldwide, with an ever-increasing heterogeneity of carbapenem resistance mechanisms, depending on the bacterial species and the geographical location. OXA-198 is a plasmid-encoded class D β-lactamase involved in carbapenem resistance in one Pseudomonas aeruginosa isolate from Belgium. In the setting of a multicenter survey of carbapenem resistance in P. aeruginosa strains in Belgian hospitals in 2013, three additional OXA-198-producing P. aeruginosa isolates originating from patients hospitalized in one hospital were detected. To reveal the molecular mechanism underlying the reduced susceptibility to carbapenems, MIC determinations, whole-genome sequencing, and PCR analyses to confirm the genetic organization were performed. The plasmid harboring the bla OXA-198 gene was characterized, along with the genetic relatedness of the four P. aeruginosa isolates. The bla OXA-198 gene was harbored on a class 1 integron carried by an ∼49-kb IncP-type plasmid proposed as IncP-11. The same plasmid was present in all four P. aeruginosa isolates. Multilocus sequence typing revealed that the isolates all belonged to sequence type 446, and single-nucleotide polymorphism analysis revealed only a few differences between the isolates. This report describes the structure of a 49-kb plasmid harboring the bla OXA-198 gene and presents the first description of OXA-198-producing P. aeruginosa isolates associated with a hospital-associated cluster episode. Copyright © 2018 American Society for Microbiology.

Investigation of a pseudo-outbreak of orthopedic infections caused by Pseudomonas aeruginosa.

PubMed

Forman, W; Axelrod, P; St John, K; Kostman, J; Khater, C; Woodwell, J; Vitagliano, R; Truant, A; Satishchandran, V; Fekete, T

1994-10-01

To report a pseudoepidemic of Pseudomonas aeruginosa infections discovered during an investigation of postoperative joint infections. A retrospective review of case patients' hospital charts, operative reports, and laboratory data, as well as environmental culturing, polymerase chain reaction (PCR) ribotyping of outbreak isolates, and in vitro analysis of P aeruginosa growth characteristics. A 510-bed, university-affiliated adult tertiary care hospital. Between October 1 and December 1, 1992, seven postsurgical joint infections were diagnosed, including four caused by P aeruginosa. A bottle of "sterile" saline used to process tissue specimens was found to be contaminated with P aeruginosa. Further investigation revealed that P aeruginosa had grown from seven additional tissue cultures, all of which had been processed with the contaminated saline. PCR ribotypes of the contaminant matched those of the clinical isolates. In vitro, P aeruginosa strains were viable in commercial nonbacteriostatic saline, but never caused visible turbidity. Six patients received antibiotics for their presumed infections; four patients had peripherally inserted central catheters placed, and one experienced severe anaphylactic reactions to several antibiotics. Pseudoepidemics due to common organisms are often difficult to detect, and delayed recognition can result in substantial morbidity. This outbreak investigation illustrates the potential for contamination of diluents in the microbiology laboratory and emphasizes the need for meticulous quality control.

Anaerobic Corrosion of 304 Stainless Steel Caused by the Pseudomonas aeruginosa Biofilm

PubMed Central

Jia, Ru; Yang, Dongqing; Xu, Dake; Gu, Tingyue

2017-01-01

Pseudomonas aeruginosa is a ubiquitous bacterium capable of forming problematic biofilms in many environments. They cause biocorrosion of medical implants and industrial equipment and infrastructure. Aerobic corrosion of P. aeruginosa against stainless steels has been reported by some researchers while there is a lack of reports on anaerobic P. aeruginosa corrosion in the literature. In this work, the corrosion by a wild-type P. aeruginosa (strain PAO1) biofilm against 304 stainless steel (304 SS) was investigated under strictly anaerobic condition for up to 14 days. The anaerobic corrosion of 304 SS by P. aeruginosa was reported for the first time. Results showed that the average sessile cell counts on 304 SS coupons after 7- and 14-day incubations were 4.8 × 107 and 6.2 × 107 cells/cm2, respectively. Scanning electron microscopy and confocal laser scanning microscopy corroborated the sessile cell counts. The X-ray diffraction analysis identified the corrosion product as iron nitride, confirming that the corrosion was caused by the nitrate reducing biofilm. The largest pit depths on 304 SS surfaces after the 7- and 14-day incubations with P. aeruginosa were 3.9 and 7.4 μm, respectively. Electrochemical tests corroborated the pitting data. PMID:29230206

The Pseudomonas aeruginosa AlgZR two-component system coordinates multiple phenotypes

PubMed Central

Okkotsu, Yuta; Little, Alexander S.; Schurr, Michael J.

2014-01-01

Pseudomonas aeruginosa is an opportunistic pathogen that causes a multitude of infections. These infections can occur at almost any site in the body and are usually associated with a breach of the innate immune system. One of the prominent sites where P. aeruginosa causes chronic infections is within the lungs of cystic fibrosis patients. P. aeruginosa uses two-component systems that sense environmental changes to differentially express virulence factors that cause both acute and chronic infections. The P. aeruginosa AlgZR two component system is one of its global regulatory systems that affects the organism's fitness in a broad manner. This two-component system is absolutely required for two P. aeruginosa phenotypes: twitching motility and alginate production, indicating its importance in both chronic and acute infections. Additionally, global transcriptome analyses indicate that it regulates the expression of many different genes, including those associated with quorum sensing, type IV pili, type III secretion system, anaerobic metabolism, cyanide and rhamnolipid production. This review examines the complex AlgZR regulatory network, what is known about the structure and function of each protein, and how it relates to the organism's ability to cause infections. PMID:24999454

Natural History of Multi-Drug Resistant Organisms in a New Military Medical Facility

DTIC Science & Technology

2012-10-01

Enterobacter cloacae  Maternity Ward  05.312  Sink top  Micrococcus  luteus  Maternity Ward  05.312  Telephone  Pantoea agglomerans  Maternity Ward...Acinetobacter baumannii  Surgical Ward  06.316  Call box  Acinetobacter  baumannii/calcoaceticus complex  Surgical Ward  06.316  Sink top  Micrococcus  luteus...Medical Ward  07.216  Sink top  Micrococcus  luteus  Medical Ward  07.216  Room Sink  Staphylococcus sciuri  ICU  02.123  Toilet seat  Staphylococcus

Accelerated corrosion of 2205 duplex stainless steel caused by marine aerobic Pseudomonas aeruginosa biofilm.

PubMed

Xu, Dake; Xia, Jin; Zhou, Enze; Zhang, Dawei; Li, Huabing; Yang, Chunguang; Li, Qi; Lin, Hai; Li, Xiaogang; Yang, Ke

2017-02-01

Microbiologically influenced corrosion (MIC) of 2205 duplex stainless steel (DSS) in the presence of Pseudomonas aeruginosa was investigated through electrochemical and surface analyses. The electrochemical results showed that P. aeruginosa significantly reduced the corrosion resistance of 2205 DSS. Confocal laser scanning microscopy (CLSM) images showed that the depths of the largest pits on 2205 DSS with and without P. aeruginosa were 14.0 and 4.9μm, respectively, indicating that the pitting corrosion was accelerated by P. aeruginosa. X-ray photoelectron spectroscopy (XPS) results revealed that CrO 3 and CrN formed on the 2205 DSS surface in the presence of P. aeruginosa. Copyright © 2016 Elsevier B.V. All rights reserved.

[The description of an esculin-positive biovar of Pseudomonas aeruginosa].

PubMed

Sivolodskiĭ, E P

2000-01-01

In the study of 280 P. aeruginosa strains isolated in different hospitals of St. Petersburg for the first time 48 strains capable of hydrolyzing esculin have been detected. The hydrolysis of esculin is determined in plates with the use of the microvolume techniques the results were evaluated after 3-hour incubation at 37 degrees C. The data confirming the existence of the exculin-positive biovar of P. aeruginosa have been obtained; these data show the wide spread of esculin-positive strains in hospitals of different specialization (17.1 +/- 5.1% of P. aeruginosa strains), the characteristic combination of the sign of esculin hydrolysis with such signs as the absence of the smell of trimethylamine and the phenomenon of "iridescent lysis" of the colonies, the stability of the sign of esculin hydrolysis in strains, repeatedly isolated from patients, after the storage of the cultures and their treatment with plasmid-eliminating preparation. The name "esculinolytica" has been proposed for this biovar. The typing strain of biovar esculinolytica has been deposited in the culture collection of the Russian Research Institute of Agricultural Microbiology as P. aeruginosa ARRIAM 64-A. This biovar been found to be most widely spread in urological hospitals, where esculin-positive strains are isolated 3 times more frequently (32.2 +/- 5.1% of P. aeruginosa strains) than in surgical hospitals (10.7 +/- 2.2%).

Cloning and characterization of EF-Tu and EF-Ts from Pseudomonas aeruginosa.

PubMed

Palmer, Stephanie O; Rangel, Edna Y; Montalvo, Alberto E; Tran, Alexis T; Ferguson, Kate C; Bullard, James M

2013-01-01

We have cloned genes encoding elongation factors EF-Tu and EF-Ts from Pseudomonas aeruginosa and expressed and purified the proteins to greater than 95% homogeneity. Sequence analysis indicated that P. aeruginosa EF-Tu and EF-Ts are 84% and 55% identical to E. coli counterparts, respectively. P. aeruginosa EF-Tu was active when assayed in GDP exchange assays. Kinetic parameters for the interaction of EF-Tu with GDP in the absence of EF-Ts were observed to be K M = 33 μM, k cat (obs) = 0.003 s(-1), and the specificity constant k cat (obs)/K M was 0.1 × 10(-3) s(-1) μM(-1). In the presence of EF-Ts, these values were shifted to K M = 2 μM, k cat (obs) = 0.005 s(-1), and the specificity constant k(cat)(obs)/K M was 2.5 × 10(-3) s(-1) μM(-1). The equilibrium dissociation constants governing the binding of EF-Tu to GDP (K GDP) were 30-75 nM and to GTP (K GTP) were 125-200 nM. EF-Ts stimulated the exchange of GDP by EF-Tu 10-fold. P. aeruginosa EF-Tu was active in forming a ternary complex with GTP and aminoacylated tRNA and was functional in poly(U)-dependent binding of Phe-tRNA(Phe) at the A-site of P. aeruginosa ribosomes. P. aeruginosa EF-Tu was active in poly(U)-programmed polyphenylalanine protein synthesis system composed of all P. aeruginosa components.

Inhibition of Pseudomonas aeruginosa biofilm formation by 2,2’-bipyridyl, lipoic, kojic and picolinic acids

PubMed Central

Çevik, Kübra; Ulusoy, Seyhan

2015-01-01

Objective(s): The inhibitory effects of iron chelators, and FeCl3 chelation on biofilm formation and swarming motility were investigated against an opportunistic human pathogen Pseudomonas aeruginosa. Materials and Methods: The inhibitory activity of 2,2’-bipyridyl, lipoic acid, kojic acid and picolinic acid on biofilm formation of P. aeruginosa strain PAO1 and three clinical isolates (P. aeruginosa PAK01, P. aeruginosa PAK02 and P. aeruginosa PAK03) were investigated, based on crystal violet assay, and swarming motility test. Results: The kojic, lipoic and picolinic acid inhibited biofilm formation by 5-33% in all tested P. aeruginosa isolates. When chelated iron was added, biofilm inhibition rates were determined to be 39-57%. Among the tested chelators against P. aeruginosa, lipoic acid (84%) and kojic acid (68%) presented the highest inhibition of swarming motility. This is the first study to report the inhibitory effect of lipoic acid on biofilm formation and swarming motility of P. aeruginosa. Conclusion: It is considered that lipoic and picolinic acids can serve as alternatives for the treatment of the P. aeruginosa infections by inhibiting biofilm formation. PMID:26557964

Carbapenem-Nonsusceptible Enterobacteriaceae in Taiwan

PubMed Central

Wang, Jann-Tay; Wu, Un-In; Lauderdale, Tsai-Ling Yang; Chen, Mei-Chen; Li, Shu-Ying; Hsu, Le-Yin; Chang, Shan-Chwen

2015-01-01

A total of 1135 carbapenem-resistant (nonsusceptible) Enterobacteriaceae (CRE) isolates were recovered between November 2010 and July 2012 (517 from 2010-2011 and 618 from 2012) from 4 hospitals in Taiwan. Carbapenemase-producing Enterobacteriaceae (CPE) comprised 5.0% (57 isolates), including 17 KPC-2 (16 Klebsiella pneumoniae and 1 Escherichia coli), 1 NDM-1 (K. oxytoca), 37 IMP-8 (26 Enterobacter cloacae, 4 Citrobacter freundii, 4 Raoultella planticola, 1 K. pneumoniae, 1 E. coli and 1 K. oxytoca), and 2 VIM-1 (1 E. cloacae, 1 E. coli). The KPC-2-positive K. pneumoniae were highly clonal even in isolates from different hospitals, and all were ST11. IMP-8 positive E. cloacae from the same hospitals showed higher similarity in PFGE pattern than those from different hospitals. A total of 518 CRE isolates (45.6%) were positive for bla ESBL, while 704 (62.0%) isolates were bla AmpC-positive, 382 (33.6% overall) of which carried both bla ESBL and bla AmpC. CTX-M (414, 80.0%) was the most common bla ESBL, while DHA (497, 70.6%) and CMY (157, 22.3%) were the most common bla AmpC. Co-carriage of bla ESBL and bla AmpC was detected in 31 (54.4%) and 15 (26.3%) of the 57 CPE, respectively. KPC-2 was the most common carbapenemase detected in K. pneumoniae (2.8%), while IMP-8 was the most common in E. cloacae (9.7%). All KPC-2-positive CRE were resistant to all three tested carbapenems. However, fourteen of the 37 IMP-8-positive CRE were susceptible to both imipenem and meropenem in vitro. Intra- and inter-hospital spread of KPC-2-producing K. pneumoniae and IMP-8-producing E. cloacae likely occurred. Although the prevalence of CPE is still low, careful monitoring is urgently needed. Non-susceptibility to ertapenem might need to be considered as one criterion of definition for CRE in areas where IMP type carbapenemase is prevalent. PMID:25794144

Immunological Interrelationships Between Cholera Toxin and the Heat-Labile and Heat-Stable Enterotoxins of Coliform Bacteria

PubMed Central

Klipstein, Frederick A.; Engert, Richard F.

1977-01-01

Cholera toxin (CT) and the heat-labile (LT) toxin of Escherichia coli are known to share antigenic properties. The present study examined the immunological relationship of CT and the LT and heat-stable (ST) toxins of E. coli, Klebsiella pneumoniae, and Enterobacter cloacae. The neutralizing capacity of equine CT antiserum and of antiserum raised in rabbits to the LT toxin of the three species of coliform bacteria was evaluated by determining their capacity to inhibit the action of purified CT and semipurified ultrafiltration preparations of the coliform LT and ST toxins in inducing water secretion as assayed by the in vivo marker perfusion technique in the rat jejunum. One milliliter of antiserum to CT and to E. coli and Klebsiella LT completely neutralized the secretory action of each of these three toxins; effective serial dilutions of CT antiserum extended to 1 to 4, whereas those of the antisera to LT were limited to 1 to 2 in most instances. One milliliter of antiserum to E. cloacae LT partially neutralized each of the three coliform LT toxins; serial dilutions were inactive. Antiserum to E. cloacae LT did not neutralize CT. Antiserum to CT and to each of the three coliform LT toxins also had a weak neutralizing effect on the ST toxins of E. coli and Klebsiella, but they did not affect E. cloacae ST. Adsorption of the antiserum to CT and to each of the three LT toxins by incubation with a heat-inactivated preparation of either the homologous or a heterologous LT toxin completely abolished the neutralizing capacity of the antisera towards both LT and ST. These observations indicate that the immunological interrelationship of CT and E. coli LT extends to the LT toxins of Klebsiella and E. cloacae and, further, that these immunological properties are shared to a lesser extent by the ST toxins of E. coli and Klebsiella. PMID:332637

Anti-Pseudomonas aeruginosa IgY antibodies augment bacterial clearance in a murine pneumonia model.

PubMed

Thomsen, K; Christophersen, L; Bjarnsholt, T; Jensen, P Ø; Moser, C; Høiby, N

2016-03-01

Oral prophylactic therapy by gargling with pathogen-specific egg yolk immunoglobulins (IgY) may reduce the initial airway colonization with Pseudomonas aeruginosa in cystic fibrosis (CF) patients. IgY antibodies impart passive immunization and we investigated the effects of anti-P. aeruginosa IgY antibodies on bacterial eradication in a murine pneumonia model. P. aeruginosa pneumonia was established in Balb/c mice and the effects of prophylactic IgY administration on lung bacteriology, clinical parameters and subsequent inflammation were compared to controls. Prophylactic administration of IgY antibodies targeting P. aeruginosa significantly reduced the bacterial burden by 2-log 24h post-infection compared to controls and was accompanied by significantly reduced clinical symptom scores and successive inflammatory cytokine profile indicative of diminished lung inflammation. Passive immunization by anti-P. aeruginosa IgY therapy facilitates promptly bacterial clearance and moderates inflammation in P. aeruginosa lung infection and may serve as an adjunct to antibiotics in reducing early colonization. Copyright © 2015. Published by Elsevier B.V.

Glycolipid-Dependent, Protease Sensitive Internalization of Pseudomonas aeruginosa Into Cultured Human Respiratory Epithelial Cells

PubMed Central

Emam, Aufaugh; Carter, William G; Lingwood, Clifford

2010-01-01

Internalization of PAK strain Pseudomonas aeruginosa into human respiratory epithelial cell lines and HeLa cervical cancer cells in vitro was readily demonstrable via a gentamycin protection assay. Depletion of target cell glycosphingolipids (GSLs) using a glucosyl ceramide synthase inhibitor, P4, completely prevented P. aeruginosa internalization. In contrast, P4 treatment had no effect on the internalization of Salmonella typhimurium into HeLa cells. Internalized P. aeruginosa were within membrane vacuoles, often containing microvesicles, between the bacterium and the limiting membrane. P. aeruginosa internalization was markedly enhanced by target cell pretreatment with the exogenous GSL, deacetyl gangliotetraosyl ceramide (Gg4). Gg4 binds the lipid raft marker, GM1 ganglioside. Target cell pretreatment with TLCK, but not other (serine) protease inhibitors, prevented both P. aeruginosa host cell binding and internalization. NFkB inhibition also prevented internalization. A GSL-containing lipid-raft model of P. aeruginosa host cell binding/internalization is proposed PMID:21270937

Enterobacteriaceae in dehydrated powdered infant formula manufactured in Indonesia and Malaysia.

PubMed

Estuningsih, Sri; Kress, Claudia; Hassan, Abdulwahed A; Akineden, Omer; Schneider, Elisabeth; Usleber, Ewald

2006-12-01

To determine the occurrence of Salmonella and Shigella in infant formula from Southeast Asia, 74 packages of dehydrated powdered infant follow-on formula (recommended age, > 4 months) from five different manufacturers, four from Indonesia and one from Malaysia, were analyzed. None of the 25-g test portions yielded Salmonella or Shigella. However, further identification of colonies growing on selective media used for Salmonella and Shigella detection revealed the frequent occurrence of several other Enterobacteriaceae species. A total of 35 samples (47%) were positive for Enterobacteriaceae. Ten samples (13.5%) from two Indonesian manufacturers yielded Enterobacter sakazakii. Other Enterobacteriaceae isolated included Pantoea spp. (n = 12), Escherichia hermanii (n = 10), Enterobacter cloacae (n = 8), Klebsiella pneumoniae subsp. pneumoniae (n = 3), Citrobacter spp. (n = 2), Serratia spp. (n = 2), and Escherichia coli (n = 2). To our knowledge, this is the first report to describe the contamination of dehydrated powdered infant formula from Indonesia with E. sakazakii and several other Enterobacteriaceae that could be opportunistic pathogens. Improper preparation and conservation of these products could result in a health risk for infants in Indonesia.

Effects of hyperbaric oxygen on Pseudomonas aeruginosa susceptibility to imipenem and macrophages.

PubMed

Lima, Flavia Luna; Joazeiro, Paulo Pinto; Lancellotti, Marcelo; de Hollanda, Luciana Maria; de Araújo Lima, Bruna; Linares, Edlaine; Augusto, Ohara; Brocchi, Marcelo; Giorgio, Selma

2015-01-01

The seriousness to treat burn wounds infected with Pseudomonas aeruginosa led us to examine whether the effect of the carbapenem antibiotic imipenem is enhanced by hyperbaric oxygen (HBO). The effects of HBO (100% O2, 3 ATA, 5 h) in combination with imipenen on bacterial counts of six isolates of P. aeruginosa and bacterial ultrastructure were investigated. Infected macrophages were exposed to HBO (100% O2, 3 ATA, 90 min) and the production of reactive oxygen species monitored. HBO enhanced the effects of imipenen. HBO increased superoxide anion production by macrophages and likely kills bacteria by oxidative mechanisms. HBO in combination with imipenem can be used to kill P. aeruginosa in vitro and such treatment may be beneficial for the patients with injuries containing the P. aeruginosa.

Phylogenetic Distribution of CRISPR-Cas Systems in Antibiotic-Resistant Pseudomonas aeruginosa.

PubMed

van Belkum, Alex; Soriaga, Leah B; LaFave, Matthew C; Akella, Srividya; Veyrieras, Jean-Baptiste; Barbu, E Magda; Shortridge, Dee; Blanc, Bernadette; Hannum, Gregory; Zambardi, Gilles; Miller, Kristofer; Enright, Mark C; Mugnier, Nathalie; Brami, Daniel; Schicklin, Stéphane; Felderman, Martina; Schwartz, Ariel S; Richardson, Toby H; Peterson, Todd C; Hubby, Bolyn; Cady, Kyle C

2015-11-24

Pseudomonas aeruginosa is an antibiotic-refractory pathogen with a large genome and extensive genotypic diversity. Historically, P. aeruginosa has been a major model system for understanding the molecular mechanisms underlying type I clustered regularly interspaced short palindromic repeat (CRISPR) and CRISPR-associated protein (CRISPR-Cas)-based bacterial immune system function. However, little information on the phylogenetic distribution and potential role of these CRISPR-Cas systems in molding the P. aeruginosa accessory genome and antibiotic resistance elements is known. Computational approaches were used to identify and characterize CRISPR-Cas systems within 672 genomes, and in the process, we identified a previously unreported and putatively mobile type I-C P. aeruginosa CRISPR-Cas system. Furthermore, genomes harboring noninhibited type I-F and I-E CRISPR-Cas systems were on average ~300 kb smaller than those without a CRISPR-Cas system. In silico analysis demonstrated that the accessory genome (n = 22,036 genes) harbored the majority of identified CRISPR-Cas targets. We also assembled a global spacer library that aided the identification of difficult-to-characterize mobile genetic elements within next-generation sequencing (NGS) data and allowed CRISPR typing of a majority of P. aeruginosa strains. In summary, our analysis demonstrated that CRISPR-Cas systems play an important role in shaping the accessory genomes of globally distributed P. aeruginosa isolates. P. aeruginosa is both an antibiotic-refractory pathogen and an important model system for type I CRISPR-Cas bacterial immune systems. By combining the genome sequences of 672 newly and previously sequenced genomes, we were able to provide a global view of the phylogenetic distribution, conservation, and potential targets of these systems. This analysis identified a new and putatively mobile P. aeruginosa CRISPR-Cas subtype, characterized the diverse distribution of known CRISPR-inhibiting genes, and

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.

[Antimicrobial resistance in gram negative bacteria isolated from intensive care units of Colombian hospitals, WHONET 2003, 2004 and 2005].

PubMed

Miranda, María Consuelo; Pérez, Federico; Zuluaga, Tania; Olivera, María del Rosario; Correa, Adriana; Reyes, Sandra Lorena; Villegas, Maria Virginia

2006-09-01

Surveillance systems play a key role in the detection and control of bacterial resistance. It is necessary to constantly collect information from all institutions because the mechanisms of bacterial resistance can operate in different ways between countries, cities and even in hospitals in the same area. Therefore local information is important in order to learn about bacterial behaviour and design appropriate interventions for each institution. Between January 2003 and December 2004, the Centro Internacional de Entrenamiento e Investigaciones Médicas (CIDEIM) developed a surveillance project in 10 tertiary hospitals in 6 cities of Colombia. Describe the trends of antibiotic resistance among the isolates of Escherichia coli, Klebsiella pneumoniae, Pseudomona aeruginosa, Acinetobacter baumannii and Enterobacter cloacae, five of the most prevalent nosocomial Gram negative pathogens. The susceptibility tests were performed by automated methods in 9 hospitals and by Kirby Bauer in 1 hospital. Antibiotics with known activity against Gram negatives, according to the Clinical Laboratory Standards Institute guidelines, were selected. The laboratories performed internal and external quality controls. During the study period, the information was downloaded monthly from the databases of each microbiology laboratory and sent to CIDEIM where it was centralized in a database using the system WHONET 5.3. The high resistance rates reported especially for A. baumannii, evidenced the presence of multidrug resistant bacteria in both ICUs and wards at every studied institution. The creation of a national surveillance network to improve our capabilities to detect, follow up, and control the antibiotic resistance in Colombia is urgently needed.

A comparison of the bacteria found on the hands of ‘homemakers’ and neonatal intensive care unit nurses

PubMed Central

Aiello, A.E.; Cimiotti, J.; Della-Latta, P.; Larson, E.L.

2007-01-01

Summary This prevalence study was conducted to compare the counts, types and antimicrobial resistance profiles of bacterial flora on the hands of individuals in the community to that of nurses at a nearby university teaching hospital, with an intense hand hygiene regimen. Hand cultures were obtained from 204 individuals during a home visit and 119 nurses in two neonatal intensive care units (NICUs). The mean total log counts of organisms were 5.73 and 5.24 for the homemakers [defined as the person (usually the mother) who is the primary person responsible for arranging childcare, cooking, cleaning etc] and nurse hands, respectively (P < 0.0001). Significantly more homemakers had Acinetobacter lwoffii, Enterobacter cloacae, Klebsiella pneumoniae, Pseudomonas aeruginosa, P. fluorescens/putida, and Staphylococcus aureus on their hands compared with the nurses (all P < 0.05). However, significantly more nurses had Enterococcus faecalis, S. epidermidis, and S. warneri on their hands (P < 0.05). Of note, the hands of nurses harboured significantly more S. epidermidis strains resistant to amoxicillin/clavulanate, cefazolin, clindamycin, erythromycin, and oxacillin and S. warneri resistant to amoxicillin/clavulanate, cefazolin, clindamycin, and oxacillin (P < 0.05). Surprisingly, significantly more trimethoprim/sulfamethoxazole-resistant S. epidermidis and ciprofloxacin-resistant S. warneri was recovered from the hands of homemakers (P < 0.05). This study demonstrates differences in prevalence, bacterial composition and antimicrobial resistance of hand flora of hospital personnel compared with homemakers. Moreover, the hands of homemakers may serve as community reservoirs for antimicrobial resistant strains of clinical importance. PMID:12919763

PCR method based on the ogdH gene for the detection of Salmonella spp. from chicken meat samples.

PubMed

Jin, Un-Ho; Cho, Sung-Hak; Kim, Min-Gon; Ha, Sang-Do; Kim, Keun-Sung; Lee, Kyu-Ho; Kim, Kwang-Yup; Chung, Duck Hwa; Lee, Young-Choon; Kim, Cheorl-Ho

2004-09-01

In a previous paper, the ogdH gene that encodes 2-oxoglutarate dehydrogenase was isolated from Salmonella typhimurium. The catalytic N-terminal region in the enzyme was found to be very specific for the Salmonella species. Therefore, the aim of the present study was to detect S. typhimurium in food sources using primers designed for OGDH-1 and OGDH-2 which were based on the salmonella-specific region of the ogdH gene. A simple polymerase chain reaction (PCR) detection method was developed to detect low numbers of S. typhimurium in a chicken meat microbial consortium. Using the ogdH-specific primers under stringent amplification conditions and for gene probe analysis, fewer than 100 colony-forming units (CFUs) were detectable when pure cultures were employed. When the PCR assay was run on S. typhimurium-contaminated meat contents, only the positive meat samples containing as few as 200 CFUs reacted to the assay. The method employed for sample processing is simple and it was determined to provide a sensitive means of detecting trace amounts of S. typhimurium-specific sequences in the presence of mixed meat microbial populations. When compared with six representative intestinal gram-negative bacterial strains in foods, including Vibrio parahaemolyticus, V. vulnificus, Enterobacter cloacae, E. coli O157:H7, Pseudomonas aeruginosa, and Proteus sp., S. typhimurium had a unique and distinct PCR product (796 bp). In conclusion, the two OGDH primers were found to be rapid and sensitive detectors of Salmonella spp for the PCR method. Copyright 2004 The Microbiological Society of Korea

Antimicrobial effects of lysophosphatidylcholine on methicillin-resistant Staphylococcus aureus.

PubMed

Miyazaki, Haruko; Midorikawa, Naoko; Fujimoto, Saki; Miyoshi, Natsumi; Yoshida, Hideto; Matsumoto, Tetsuya

2017-07-01

Methicillin-resistant Staphylococcus aureus (MRSA) is an important health care-associated and community-associated pathogen and causes a large number of infections worldwide. For the purpose of application to topical treatment of MRSA infection, we examined the antimicrobial effects of lysophosphatidylcholine (LPC) on MRSA strains. We also investigated the combination effect of LPC and gentamicin on MRSA growth. The LPC minimum inhibitory concentrations (MIC) for Gram-positive ( S. aureus, Staphylococcus epidermidis , and Streptococcus pneumoniae ) and Gram-negative ( Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae , and Pseudomonas aeruginosa ) bacteria were measured by the broth microdilution method. The mechanism of LPC-mediated MRSA killing was investigated by membrane permeability analysis with DiSC3(5) fluorescence and growth curve analysis. Lastly, the effects of LPC on gentamicin-induced bactericidal activity were determined in combination treatment studies with 15 gentamicin-resistant MRSA isolates from the skin, nose, or ears. The LPC MIC for Gram-positive bacteria varied between 32 µg/ml and >2048 µg/ml, whereas that for all Gram-negative bacteria was >2048 µg/ml. Consistently, membrane permeability analysis showed that LPC was substantially more effective in inducing membrane permeability in Gram-positive bacteria than in Gram-negative counterparts. Growth curve analysis in cotreatment studies demonstrated that LPC has intrinsic bactericidal effects and can also potentiate gentamicin sensitivity in resistant MRSA strains. Our study demonstrates that LPC exhibits intrinsic antimicrobial effects and can enhance the antimicrobial effects of gentamicin for resistant MRSA strains, suggesting that LPC may be a beneficial additive in topical antibiotics for superficial skin infections.

Aspergillus fumigatus enhances elastase production in Pseudomonas aeruginosa co-cultures.

PubMed

Smith, Karen; Rajendran, Ranjith; Kerr, Stephen; Lappin, David F; Mackay, William G; Williams, Craig; Ramage, Gordon

2015-09-01

In the cystic fibrosis (CF) lung the presence of bacteria and fungi in the airways promotes an inflammatory response causing progressive lung damage, ultimately leading to high rates of morbidity and mortality. We hypothesized that polymicrobial interactions play an important role in promoting airway pathogenesis. We therefore examined the interplay between the most commonly isolated bacterial CF pathogen, Pseudomonas aeruginosa, and the most prevalent filamentous fungi, Aspergillus fumigatus, to test this. Co-culture experiments showed that in the presence of A. fumigatus the production of P. aeruginosa elastase was enhanced. This was confirmed by the presence of zones of clearance on Elastin-Congo Red (ECR) agar, which was identified as elastase by mass spectrometry. When P. aeruginosa were grown in a co-culture model with mature A. fumigatus biofilms, 60% of isolates produced significantly more elastase in the presence of the filamentous fungi than in its absence (P < .05). The expression of lasB also increased when P. aeruginosa isolates PA01 and PA14 were grown in co-culture with A. fumigatus. Supernatants from co-culture experiments were also significantly toxic to a human lung epithelial cell line (19-38% cell cytotoxicity) in comparison to supernatants from P. aeruginosa only cultures (P < .0001). Here we report that P. aeruginosa cytotoxic elastase is enhanced in the presence of the filamentous fungi A. fumigatus, suggesting that this may have a role to play in the damaging pathology associated with the lung tissue in this disease. This indicates that patients who have a co-colonisation with these two organisms may have a poorer prognosis. © The Author 2015. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Pseudomonas aeruginosa infection in cystic fibrosis: pathophysiological mechanisms and therapeutic approaches.

PubMed

Lund-Palau, Helena; Turnbull, Andrew R; Bush, Andrew; Bardin, Emmanuelle; Cameron, Loren; Soren, Odel; Wierre-Gore, Natasha; Alton, Eric W F W; Bundy, Jacob G; Connett, Gary; Faust, Saul N; Filloux, Alain; Freemont, Paul; Jones, Andy; Khoo, Valerie; Morales, Sandra; Murphy, Ronan; Pabary, Rishi; Simbo, Ameze; Schelenz, Silke; Takats, Zoltan; Webb, Jeremy; Williams, Huw D; Davies, Jane C

2016-06-01

Pseudomonas aeruginosa is a remarkably versatile environmental bacterium with an extraordinary capacity to infect the cystic fibrosis (CF) lung. Infection with P. aeruginosa occurs early, and although eradication can be achieved following early detection, chronic infection occurs in over 60% of adults with CF. Chronic infection is associated with accelerated disease progression and increased mortality. Extensive research has revealed complex mechanisms by which P. aeruginosa adapts to and persists within the CF airway. Yet knowledge gaps remain, and prevention and treatment strategies are limited by the lack of sensitive detection methods and by a narrow armoury of antibiotics. Further developments in this field are urgently needed in order to improve morbidity and mortality in people with CF. Here, we summarize current knowledge of pathophysiological mechanisms underlying P. aeruginosa infection in CF. Established treatments are discussed, and an overview is offered of novel detection methods and therapeutic strategies in development.

Trehalose 6-phosphate phosphatases of Pseudomonas aeruginosa.

PubMed

Cross, Megan; Biberacher, Sonja; Park, Suk-Youl; Rajan, Siji; Korhonen, Pasi; Gasser, Robin B; Kim, Jeong-Sun; Coster, Mark J; Hofmann, Andreas

2018-04-24

The opportunistic bacterium Pseudomonas aeruginosa has been recognized as an important pathogen of clinical relevance and is a leading cause of hospital-acquired infections. The presence of a glycolytic enzyme in Pseudomonas, which is known to be inhibited by trehalose 6-phosphate (T6P) in other organisms, suggests that these bacteria may be vulnerable to the detrimental effects of intracellular T6P accumulation. In the present study, we explored the structural and functional properties of trehalose 6-phosphate phosphatase (TPP) in P. aeruginosa in support of future target-based drug discovery. A survey of genomes revealed the existence of 2 TPP genes with either chromosomal or extrachromosomal location. Both TPPs were produced as recombinant proteins, and characterization of their enzymatic properties confirmed specific, magnesium-dependent catalytic hydrolysis of T6P. The 3-dimensional crystal structure of the chromosomal TPP revealed a protein dimer arising through β-sheet expansion of the individual monomers, which possess the overall fold of halo-acid dehydrogenases.-Cross, M., Biberacher, S., Park, S.-Y., Rajan, S., Korhonen, P., Gasser, R. B., Kim, J.-S., Coster, M. J., Hofmann, A. Trehalose 6-phosphate phosphatases of Pseudomonas aeruginosa.

Pseudomonas aeruginosa quorum sensing molecules correlate with clinical status in cystic fibrosis.

PubMed

Barr, Helen L; Halliday, Nigel; Cámara, Miguel; Barrett, David A; Williams, Paul; Forrester, Douglas L; Simms, Rebecca; Smyth, Alan R; Honeybourne, David; Whitehouse, Joanna L; Nash, Edward F; Dewar, Jane; Clayton, Andrew; Knox, Alan J; Fogarty, Andrew W

2015-10-01

Pseudomonas aeruginosa produces quorum sensing signal molecules that are potential biomarkers for infection.A prospective study of 60 cystic fibrosis patients with chronic P. aeruginosa, who required intravenous antibiotics for pulmonary exacerbations, was undertaken. Clinical measurements and biological samples were obtained at the start and end of the treatment period. Additional data were available for 29 of these patients when they were clinically stable.Cross-sectionally, quorum sensing signal molecules were detectable in the sputum, plasma and urine of 86%, 75% and 83% patients, respectively. They were positively correlated between the three biofluids. Positive correlations were observed for most quorum sensing signal molecules in sputum, plasma and urine, with quantitative measures of pulmonary P. aeruginosa load at the start of a pulmonary exacerbation. Plasma concentrations of 2-nonyl-4-hydroxy-quinoline (NHQ) were significantly higher at the start of a pulmonary exacerbation compared to clinical stability (p<0.01). Following the administration of systemic antibiotics, plasma 2-heptyl-4-hydroxyquinoline (p=0.02) and NHQ concentrations (p<0.01) decreased significantly.In conclusion, quorum sensing signal molecules are detectable in cystic fibrosis patients with pulmonary P. aeruginosa infection and are positively correlated with quantitative measures of P. aeruginosa. NHQ correlates with clinical status and has potential as a novel biomarker for P. aeruginosa infection. Copyright ©ERS 2015.

Interactions between Microcystis aeruginosa and coexisting amoxicillin contaminant at different phosphorus levels.

PubMed

Liu, Ying; Chen, Shi; Chen, Xiao; Zhang, Jian; Gao, Baoyu

2015-10-30

Microcystis aeruginosa was cultured with 0.05-5 mg L(-1) of phosphorus and exposed to 200-500 ng L(-1) of amoxicillin for seven days. Amoxicillin presented no significant effect (p>0.05) on the growth of M. aeruginosa at phosphorus levels of 0.05 and 0.2 mg L(-1), but stimulated algal growth as a hormesis effect at phosphorus levels of 1 and 5 mg L(-1). Phosphorus and amoxicillin affected the contents of chlorophyll-a, adenosine triphosphate (ATP) and malondialdehyde, the expression of psbA and rbcL, as well as the activities of adenosinetriphosphatase and glutathione S-transferase in similar manners, but regulated the production and release of microcystins and the activities of superoxide dismutase and peroxidase in different ways. Increased photosynthesis activity was related with the ATP consumption for the stress response to amoxicillin, and the stress response was enhanced as the phosphorus concentration increased. The biodegradation of amoxicillin by M. aeruginosa increased from 11.5% to 28.2% as the phosphorus concentration increased. Coexisting amoxicillin aggravated M. aeruginosa pollution by increasing cell density and concentration of microcystins, while M. aeruginosa alleviated amoxicillin pollution via biodegradation. The interactions between M. aeruginosa and amoxicillin were significantly regulated by phosphorus (p<0.05) and led to a complicated situation of combined pollution. Copyright © 2015 Elsevier B.V. All rights reserved.

Pseudomonas aeruginosa quorum sensing molecules correlate with clinical status in cystic fibrosis

PubMed Central

Halliday, Nigel; Cámara, Miguel; Barrett, David A.; Williams, Paul; Forrester, Douglas L.; Simms, Rebecca; Smyth, Alan R.; Honeybourne, David; Whitehouse, Joanna L.; Nash, Edward F.; Dewar, Jane; Clayton, Andrew; Knox, Alan J.; Fogarty, Andrew W.

2015-01-01

Pseudomonas aeruginosa produces quorum sensing signal molecules that are potential biomarkers for infection. A prospective study of 60 cystic fibrosis patients with chronic P. aeruginosa, who required intravenous antibiotics for pulmonary exacerbations, was undertaken. Clinical measurements and biological samples were obtained at the start and end of the treatment period. Additional data were available for 29 of these patients when they were clinically stable. Cross-sectionally, quorum sensing signal molecules were detectable in the sputum, plasma and urine of 86%, 75% and 83% patients, respectively. They were positively correlated between the three biofluids. Positive correlations were observed for most quorum sensing signal molecules in sputum, plasma and urine, with quantitative measures of pulmonary P. aeruginosa load at the start of a pulmonary exacerbation. Plasma concentrations of 2-nonyl-4-hydroxy-quinoline (NHQ) were significantly higher at the start of a pulmonary exacerbation compared to clinical stability (p<0.01). Following the administration of systemic antibiotics, plasma 2-heptyl-4-hydroxyquinoline (p=0.02) and NHQ concentrations (p<0.01) decreased significantly. In conclusion, quorum sensing signal molecules are detectable in cystic fibrosis patients with pulmonary P. aeruginosa infection and are positively correlated with quantitative measures of P. aeruginosa. NHQ correlates with clinical status and has potential as a novel biomarker for P. aeruginosa infection. PMID:26022946

Phylogenetic Distribution of CRISPR-Cas Systems in Antibiotic-Resistant Pseudomonas aeruginosa

PubMed Central

van Belkum, Alex; Soriaga, Leah B.; LaFave, Matthew C.; Akella, Srividya; Veyrieras, Jean-Baptiste; Barbu, E. Magda; Shortridge, Dee; Blanc, Bernadette; Hannum, Gregory; Zambardi, Gilles; Miller, Kristofer; Enright, Mark C.; Mugnier, Nathalie; Brami, Daniel; Schicklin, Stéphane; Felderman, Martina; Schwartz, Ariel S.; Richardson, Toby H.; Peterson, Todd C.; Hubby, Bolyn

2015-01-01

ABSTRACT Pseudomonas aeruginosa is an antibiotic-refractory pathogen with a large genome and extensive genotypic diversity. Historically, P. aeruginosa has been a major model system for understanding the molecular mechanisms underlying type I clustered regularly interspaced short palindromic repeat (CRISPR) and CRISPR-associated protein (CRISPR-Cas)-based bacterial immune system function. However, little information on the phylogenetic distribution and potential role of these CRISPR-Cas systems in molding the P. aeruginosa accessory genome and antibiotic resistance elements is known. Computational approaches were used to identify and characterize CRISPR-Cas systems within 672 genomes, and in the process, we identified a previously unreported and putatively mobile type I-C P. aeruginosa CRISPR-Cas system. Furthermore, genomes harboring noninhibited type I-F and I-E CRISPR-Cas systems were on average ~300 kb smaller than those without a CRISPR-Cas system. In silico analysis demonstrated that the accessory genome (n = 22,036 genes) harbored the majority of identified CRISPR-Cas targets. We also assembled a global spacer library that aided the identification of difficult-to-characterize mobile genetic elements within next-generation sequencing (NGS) data and allowed CRISPR typing of a majority of P. aeruginosa strains. In summary, our analysis demonstrated that CRISPR-Cas systems play an important role in shaping the accessory genomes of globally distributed P. aeruginosa isolates. PMID:26604259

Photodynamic antimicrobial therapy to inhibit pseudomonas aeruginosa of corneal isolates (Conference Presentation)

NASA Astrophysics Data System (ADS)

Durkee, Heather A.; Relhan, Nidhi; Arboleda, Alejandro; Halili, Francisco; De Freitas, Carolina; Alawa, Karam; Aguilar, Mariela C.; Amescua, Guillermo; Miller, Darlene; Parel, Jean-Marie

2016-03-01

Keratitis associated with Pseudomonas aeruginosa is difficult to manage. Treatment includes antibiotic eye drops, however, some strains of Pseudomonas aeruginosa are resistant. Current research efforts are focused on finding alternative and adjunct therapies to treat multi-drug resistant bacteria. One promising alternate technique is photodynamic therapy (PDT). The purpose of this study was to evaluate the effect of riboflavin- and rose bengal-mediated PDT on Pseudomonas aeruginosa keratitis isolates in vitro. Two isolates (S+U- and S-U+) of Pseudomonas aeruginosa were derived from keratitis patients and exposed to five experimental groups: (1) Control (dark, UV-A irradiation, 525nm irradiation); (2) 0.1% riboflavin (dark, UV-A irradiation); and (3) 0.1% rose bengal, (4) 0.05% rose bengal and (5) 0.01% rose bengal (dark, 525nm irradiation). Three days after treatment, in dark conditions of all concentration of riboflavin and rose bengal showed no inhibition in both S+U- and S-U+ strains of Pseudomonas aeruginosa. In 0.1% and 0.05% rose bengal irradiated groups, for both S+U- and S-U+ strains, there was complete inhibition of bacterial growth in the central 50mm zone corresponding to the diameter of the green light source. These in vitro results suggest that rose bengal photodynamic therapy may be an effective adjunct treatment for Pseudomonas aeruginosa keratitis.

Coexistence of metallo-beta-lactamase-encoding genes in Pseudomonas aeruginosa.

PubMed

Mohanam, Lavanya; Menon, Thangam

2017-07-01

The emergence and rapid spread of carbapenem resistance mediated by metallo-beta-lactamase (MBL) in Pseudomonas aeruginosa is of major concern due to limited therapeutic options. This study was aimed at detecting the presence of MBL and its association with integrons in imipenem-resistant P. aeruginosa isolates and to determine their genetic relatedness. A total of 213 P. aeruginosa isolates were collected from two tertiary care centres and tested against anti-pseudomonal antibiotics by antimicrobial susceptibility testing, followed by the detection of MBL production by combined disk method. Minimum inhibitory concentration (MIC) of meropenem was determined by E-test. Multiplex polymerase chain reaction (PCR) was performed for the detection of blaSPM, blaIMP, blaVIM, blaNDM, blaGIM and blaSIM. PCR was carried out to characterize the variable region of class 1 integron. Transcongujation assay was carried out for the confirmation of plasmid-mediated resistance. Enterobacterial repetitive intergenic consensus sequence (ERIC)-PCR was performed for determining the genetic relatedness among P. aeruginosa isolates. Of the 213 P. aeruginosa isolates, 22 (10%) were found to be carbapenem resistant and these were from pus 18 (82%), urine 2 (9%), sputum 1 (5%) and tracheal wash 1 (5%). Among 22 isolates, 18 (81.8%) were found to be MBL producers by phenotypic method and MIC range of meropenem was 8 to >32 μg/ml. PCR amplification showed that 20 (91%) isolates carried any one of the MBL genes tested: blaVIM and blaNDM in seven (32%) and six (27%) isolates, respectively; blaVIM and blaNDMin three (14%); blaIMP and blaNDM in two (9%); blaVIM and blaIMP in one (5%) isolate. The blaVIM, blaIMP and blaNDM were found to co-exist in one isolate. None of the isolates were positive for blaSPM, blaSIM and blaGIM. All 22 isolates carried class I integron. Of the 20 MBL-positive isolates, transconjugants were obtained for 15 isolates. ERIC-PCR analysis showed all isolates to be clonally

[The effect of biyuanshu oral liquid on the formation of Pseudomonas aeruginosa biofilms in vitro].

PubMed

Liu, Xiang; Chen, Haihong; Wang, Shengqing

2012-07-01

To observe the effect of biyuanshu oral liquid on the formation of pseudomonas aeruginosa biofilms in vitro. Pseudomonas aeruginosa biofilm was established by plate culture and detected by Scanning electron microscopy and AgNO3 staining. After treated with different dosages of biyuanshu oral liquid and erythromycin, the pseudomonas aeruginosa biofilms were observed by AgNO3 staining and the number of viable bacteria were measured by serial dilution. The pseudomonas aeruginosa biofilms could be detected by SEM at the seventh culture day and it was consistent with the detection of AgNO3 staining. The biyuanshu oral liquid and erythromycin have the effect on inhibiting the formation of pseudomonas aeruginosa biofilms. But with the already formed pseudomonas aeruginosa biofilms the inhibition was not significant. The serial dilution method showed that the viable counts of bacteria of biyuanshu oral liquid and erythromycin treated groups were significantly lower than those untreated groups (P < 0.05). The biyuanshu oral liquid and erythromycin can inhibit the formation of pseudomonas aeruginosa biofilms in vitro.

Molecular characterization of class b carbapenemases in advanced stage of dissemination and emergence of class d carbapenemases in Enterobacteriaceae from Croatia.

PubMed

Bedenić, Branka; Sardelić, Sanda; Luxner, Josefa; Bošnjak, Zrinka; Varda-Brkić, Dijana; Lukić-Grlić, Amarela; Mareković, Ivana; Frančula-Zaninović, Sonja; Krilanović, Marija; Šijak, Dorotea; Grisold, Andrea; Zarfel, Gernot

2016-09-01

Carbapenemases involved in acquired carbapenem resistance in Enterobacteriaceae belong to Ambler class A serin β-lactamases, class B metallo-β-lactamases (MBL) or class D OXA-48-like β-lactamases. The aim of the present study was to analyse the molecular epidemiology and the mechanisms and routes of spread of class B and class D carbapenemases in Croatia. In total 68 isolates were analyzed. Antibiotic susceptibility was determined by broth microdilution method. PCR was used to detect antibiotic-resistance genes. Genotyping was performed by rep-PCR and MLST. Sixty-five isolates were found to harbour VIM-1 carbapenemase, seven of which were positive also for NDM-1, while two strains harboured only NDM-1. OXA-48 was detected in three isolates, two of which coproduced VIM-1. Thirty-six strains possessed additional CTX-M-15 β-lactamase whereas 64 were positive for TEM-1. CMY was found in 18 Citrobacter freundii isolates and DHA-1 in one Enterobacter cloacae isolate. Four different plasmid-incompatibility groups were found: A/C, L/M, N and FIIAs. Unlike C. freundii and E. cloacae, Klebsiella pneumoniae showed high diversity of rep-PCR patterns. E. cloacae and C. freundii predominantly belonged to one large clone which was allocated to ST105 and ST24, respectively. Three different types of carbapenemases were identified showing the complexity of CRE in Croatia. Copyright © 2016 Elsevier B.V. All rights reserved.

Application of bacteriophages to selectively remove Pseudomonas aeruginosa in water and wastewater filtration systems.

PubMed

Zhang, Yanyan; Hunt, Heather K; Hu, Zhiqiang

2013-09-01

Water and wastewater filtration systems often house pathogenic bacteria, which must be removed to ensure clean, safe water. Here, we determine the persistence of the model bacterium Pseudomonas aeruginosa in two types of filtration systems, and use P. aeruginosa bacteriophages to determine their ability to selectively remove P. aeruginosa. These systems used beds of either anthracite or granular activated carbon (GAC), which were operated at an empty bed contact time (EBCT) of 45 min. The clean bed filtration systems were loaded with an instantaneous dose of P. aeruginosa at a total cell number of 2.3 (± 0.1 [standard deviation]) × 10(7) cells. An immediate dose of P. aeruginosa phages (1 mL of phage stock at the concentration of 2.7 × 10(7) PFU (Plaque Forming Units)/mL) resulted in a reduction of 50% (± 9%) and >99.9% in the effluent P. aeruginosa concentrations in the clean anthracite and GAC filters, respectively. To further evaluate the effects of P. aeruginosa phages, synthetic stormwater was run through anthracite and GAC biofilters where mixed-culture biofilms were present. Eighty five days after an instantaneous dose of P. aeruginosa (2.3 × 10(7) cells per filter) on day 1, 7.5 (± 2.8) × 10(7) and 1.1 (± 0.5) × 10(7) P. aeruginosa cells/g filter media were detected in the top layer (close to the influent port) of the anthracite and GAC biofilters, respectively, demonstrating the growth and persistence of pathogenic bacteria in the biofilters. A subsequent 1-h dose of phages, at the concentration of 5.1 × 10(6) PFU/mL and flow rate of 1.6 mL/min, removed the P. aeruginosa inside the GAC biofilters and the anthracite biofilters by 70% (± 5%) and 56% (± 1%), respectively, with no P. aeruginosa detected in the effluent, while not affecting ammonia oxidation or the ammonia-oxidizing bacterial community inside the biofilters. These results suggest that phage treatment can selectively remove pathogenic bacteria with minimal impact on beneficial

Pseudomonas aeruginosa isolation in patients with non-cystic fibrosis bronchiectasis: a retrospective study.

PubMed

Wang, Hong; Ji, Xiao-Bin; Mao, Bei; Li, Cheng-Wei; Lu, Hai-Wen; Xu, Jin-Fu

2018-03-14

Pseudomonas aeruginosa (P. aeruginosa) occupies an important niche in the pathogenic microbiome of bronchiectasis. The objective of this study is to evaluate the clinical characteristics and prognostic value of P. aeruginosa in Chinese adult patients with bronchiectasis. This retrospective and follow-up study enrolled 1188 patients diagnosed with bronchiectasis at Shanghai Pulmonary Hospital between January 2011 and December 2012. The patients' clinical data including anthropometry, clinical symptoms, serum biomarkers, radiographic manifestations and lung function indices were reviewed. The median follow-up duration (IQR) was 44 (40-54) months, during which 289 patients were lost to follow-up. Data from 899 patients were collected and analysed for the outcomes of mortality, annual exacerbation frequency and health-related quality of life. P. aeruginosa was isolated from 232 patients, alongside other pathogens such as Aspergillus (n=75) and Candida albicans (n=72). There were 74 deaths (12% of patients with P. aeruginosa , 7.3% of those without) over the course of the follow-up. The isolation of P. aeruginosa was a risk factor for all-cause mortality (HR, 3.07; 95% CI 1.32 to 7.15) and was associated with high rates of exacerbations (ie, ≥3 exacerbations per year of follow-up) (HR, 2.40; 95% CI 1.20 to 4.79). Patients with P. aeruginosa also had worse scores on the Hospital Anxiety and Depression Scale (anxiety, p=0.005; depression, p<0.001), the Leicester Cough Questionnaire (p=0.033) and the modified Medical Research Council scale (p=0.001) compared with those without P. aeruginosa . Isolation of P. aeruginosa in patients with bronchiectasis is a significant prognostic indicator and should be a major factor in the clinical management of the disease. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

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.

Strain- and Substrate-Dependent Redox Mediator and Electricity Production by Pseudomonas aeruginosa

PubMed Central

Bosire, Erick M.; Blank, Lars M.

2016-01-01

ABSTRACT Pseudomonas aeruginosa is an important, thriving member of microbial communities of microbial bioelectrochemical systems (BES) through the production of versatile phenazine redox mediators. Pure culture experiments with a model strain revealed synergistic interactions of P. aeruginosa with fermenting microorganisms whereby the synergism was mediated through the shared fermentation product 2,3-butanediol. Our work here shows that the behavior and efficiency of P. aeruginosa in mediated current production is strongly dependent on the strain of P. aeruginosa. We compared levels of phenazine production by the previously investigated model strain P. aeruginosa PA14, the alternative model strain P. aeruginosa PAO1, and the BES isolate Pseudomonas sp. strain KRP1 with glucose and the fermentation products 2,3-butanediol and ethanol as carbon substrates. We found significant differences in substrate-dependent phenazine production and resulting anodic current generation for the three strains, with the BES isolate KRP1 being overall the best current producer and showing the highest electrochemical activity with glucose as a substrate (19 μA cm−2 with ∼150 μg ml−1 phenazine carboxylic acid as a redox mediator). Surprisingly, P. aeruginosa PAO1 showed very low phenazine production and electrochemical activity under all tested conditions. IMPORTANCE Microbial fuel cells and other microbial bioelectrochemical systems hold great promise for environmental technologies such as wastewater treatment and bioremediation. While there is much emphasis on the development of materials and devices to realize such systems, the investigation and a deeper understanding of the underlying microbiology and ecology are lagging behind. Physiological investigations focus on microorganisms exhibiting direct electron transfer in pure culture systems. Meanwhile, mediated electron transfer with natural redox compounds produced by, for example, Pseudomonas aeruginosa might enable an

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

Strong incidence of Pseudomonas aeruginosa on bacterial rrs and ITS genetic structures of cystic fibrosis sputa

PubMed Central

Pages-Monteiro, Laurence; Marti, Romain; Commun, Carine; Alliot, Nolwenn; Bardel, Claire; Meugnier, Helene; Perouse-de-Montclos, Michele; Reix, Philippe; Durieu, Isabelle; Durupt, Stephane; Vandenesch, Francois; Freney, Jean; Cournoyer, Benoit; Doleans-Jordheim, Anne

2017-01-01

Cystic fibrosis (CF) lungs harbor a complex community of interacting microbes, including pathogens like Pseudomonas aeruginosa. Meta-taxogenomic analysis based on V5-V6 rrs PCR products of 52 P. aeruginosa-positive (Pp) and 52 P. aeruginosa-negative (Pn) pooled DNA extracts from CF sputa suggested positive associations between P. aeruginosa and Stenotrophomonas and Prevotella, but negative ones with Haemophilus, Neisseria and Burkholderia. Internal Transcribed Spacer analyses (RISA) from individual DNA extracts identified three significant genetic structures within the CF cohorts, and indicated an impact of P. aeruginosa. RISA clusters Ip and IIIp contained CF sputa with a P. aeruginosa prevalence above 93%, and of 24.2% in cluster IIp. Clusters Ip and IIIp showed lower RISA genetic diversity and richness than IIp. Highly similar cluster IIp RISA profiles were obtained from two patients harboring isolates of a same P. aeruginosa clone, suggesting convergent evolution in the structure of their microbiota. CF patients of cluster IIp had received significantly less antibiotics than patients of clusters Ip and IIIp but harbored the most resistant P. aeruginosa strains. Patients of cluster IIIp were older than those of Ip. The effects of P. aeruginosa on the RISA structures could not be fully dissociated from the above two confounding factors but several trends in these datasets support the conclusion of a strong incidence of P. aeruginosa on the genetic structure of CF lung microbiota. PMID:28282386

Pseudomonas aeruginosa adapts its iron uptake strategies in function of the type of infections

PubMed Central

Cornelis, Pierre; Dingemans, Jozef

2013-01-01

Pseudomonas aeruginosa is a Gram-negative γ-Proteobacterium which is known for its capacity to colonize various niches, including some invertebrate and vertebrate hosts, making it one of the most frequent bacteria causing opportunistic infections. P. aeruginosa is able to cause acute as well as chronic infections and it uses different colonization and virulence factors to do so. Infections range from septicemia, urinary infections, burn wound colonization, and chronic colonization of the lungs of cystic fibrosis patients. Like the vast majority of organisms, P. aeruginosa needs iron to sustain growth. P. aeruginosa utilizes different strategies to take up iron, depending on the type of infection it causes. Two siderophores are produced by this bacterium, pyoverdine and pyochelin, characterized by high and low affinities for iron respectively. P. aeruginosa is also able to utilize different siderophores from other microorganisms (siderophore piracy). It can also take up heme from hemoproteins via two different systems. Under microaerobic or anaerobic conditions, P. aeruginosa is also able to take up ferrous iron via its Feo system using redox-cycling phenazines. Depending on the type of infection, P. aeruginosa can therefore adapt by switching from one iron uptake system to another as we will describe in this short review. PMID:24294593

Swimming Motility Mediates the Formation of Neutrophil Extracellular Traps Induced by Flagellated Pseudomonas aeruginosa

PubMed Central

Sil, Payel; Chassaing, Benoit; Yoo, Dae-goon; Gewirtz, Andrew T.; Goldberg, Joanna B.; McCarter, Linda L.; Rada, Balázs

2016-01-01

Pseudomonas aeruginosa is an opportunistic pathogen causing severe infections often characterized by robust neutrophilic infiltration. Neutrophils provide the first line of defense against P. aeruginosa. Aside from their defense conferred by phagocytic activity, neutrophils also release neutrophil extracellular traps (NETs) to immobilize bacteria. Although NET formation is an important antimicrobial process, the details of its mechanism are largely unknown. The identity of the main components of P. aeruginosa responsible for triggering NET formation is unclear. In this study, our focus was to identify the main bacterial factors mediating NET formation and to gain insight into the underlying mechanism. We found that P. aeruginosa in its exponential growth phase promoted strong NET formation in human neutrophils while its NET-inducing ability dramatically decreased at later stages of bacterial growth. We identified the flagellum as the primary component of P. aeruginosa responsible for inducing NET extrusion as flagellum-deficient bacteria remained seriously impaired in triggering NET formation. Purified P. aeruginosa flagellin, the monomeric component of the flagellum, does not stimulate NET formation in human neutrophils. P. aeruginosa-induced NET formation is independent of the flagellum-sensing receptors TLR5 and NLRC4 in both human and mouse neutrophils. Interestingly, we found that flagellar motility, not flagellum binding to neutrophils per se, mediates NET release induced by flagellated bacteria. Immotile, flagellar motor-deficient bacterial strains producing paralyzed flagella did not induce NET formation. Forced contact between immotile P. aeruginosa and neutrophils restored their NET-inducing ability. Both the motAB and motCD genetic loci encoding flagellar motor genes contribute to maximal NET release; however the motCD genes play a more important role. Phagocytosis of P. aeruginosa and superoxide production by neutrophils were also largely dependent upon

Solar Disinfection of Pseudomonas aeruginosa in Harvested Rainwater: A Step towards Potability of Rainwater

PubMed Central

Amin, Muhammad T.; Nawaz, Mohsin; Amin, Muhammad N.; Han, Mooyoung

2014-01-01

Efficiency of solar based disinfection of Pseudomonas aeruginosa (P. aeruginosa) in rooftop harvested rainwater was evaluated aiming the potability of rainwater. The rainwater samples were exposed to direct sunlight for about 8–9 hours and the effects of water temperature (°C), sunlight irradiance (W/m2), different rear surfaces of polyethylene terephthalate bottles, variable microbial concentrations, pH and turbidity were observed on P. aeruginosa inactivation at different weathers. In simple solar disinfection (SODIS), the complete inactivation of P. aeruginosa was obtained only under sunny weather conditions (>50°C and >700 W/m2) with absorptive rear surface. Solar collector disinfection (SOCODIS) system, used to improve the efficiency of simple SODIS under mild and weak weather, completely inactivated the P. aeruginosa by enhancing the disinfection efficiency of about 20% only at mild weather. Both SODIS and SOCODIS systems, however, were found inefficient at weak weather. Different initial concentrations of P. aeruginosa and/or Escherichia coli had little effects on the disinfection efficiency except for the SODIS with highest initial concentrations. The inactivation of P. aeruginosa increased by about 10–15% by lowering the initial pH values from 10 to 3. A high initial turbidity, adjusted by adding kaolin, adversely affected the efficiency of both systems and a decrease, about 15–25%; in inactivation of P. aeruginosa was observed. The kinetics of this study was investigated by Geeraerd Model for highlighting the best disinfection system based on reaction rate constant. The unique detailed investigation of P. aeruginosa disinfection with sunlight based disinfection systems under different weather conditions and variable parameters will help researchers to understand and further improve the newly invented SOCODIS system. PMID:24595188

Anti-Quorum Sensing Activity of Forsythia suspense on Chromobacterium violaceum and Pseudomonas aeruginosa.

PubMed

Zhang, An; Chu, Wei-Hua

2017-01-01

Quorum sensing (QS) plays an important role in the production of virulence factors and pathogenicity in Pseudomonas aeruginosa , and the interruption of QS will be a hopeful pathway to combat bacterial infection. In this study, we selected Forsythia suspense (Thunb.) Vahl from traditional Chinese herbal medicines for its anti-QS activity. Anti-QS of F. suspense extracts (FSE) was monitored using the Chromobacterium violaceum 12472 bioassay. Standard methods were used to investigate the effects of FSE on QS-controlled virulence factors production, swimming motility, and biofilm establishment in P. aeruginosa PAO1. FSE could obviously inhibit the violacein production in C. violaceum 12472 and also could inhibit quorum sensing-regulated virulence factors production and biofilm formation in P. aeruginosa in a concentration-dependent manner. The elastase activity and pyocyanin production were inhibited at a maximum of 40.97 and 47.58% when P. aeruginosa was grown in the presence of 0.25 g/mL FSE, which can also inhibit swimming motility of P. aeruginosa . The biofilm formation ability was decreased about 72.45% when in PAO1 cultured with the 0.25 g/mL FSE. The results suggested that FSE may be used as an alternative drug to control and handle harmful infections caused by bacterial pathogens based on QS inhibition. Forsythia suspense water extract could obviously inhibit the purple pigment production in C. violaceum 12472 Forsythia suspense water extract could inhibit QS-regulated virulence factors production and biofilm formation in P. aeruginosa . Abbreviations used: QS: Quorum sensing, Pseudomonas aeruginosa P. aeruginosa , Forsythia suspense F. suspense , FSE: F. suspense extracts, Chromobacterium violaceum 12472 C. violaceum 12472, AIs: autoinducers, AHLs: N -acyl-homoserinelactones, LB: Luria-Bertani, MICs: Minimum inhibitory concentrations, CFU: Colony-Forming Units, ATCC: American Type Culture Collection, PBS: phosphate buffered saline.

Anti-Quorum Sensing Activity of Forsythia suspense on Chromobacterium violaceum and Pseudomonas aeruginosa

PubMed Central

Zhang, An; Chu, Wei-Hua

2017-01-01

Background: Quorum sensing (QS) plays an important role in the production of virulence factors and pathogenicity in Pseudomonas aeruginosa, and the interruption of QS will be a hopeful pathway to combat bacterial infection. Objective: In this study, we selected Forsythia suspense (Thunb.) Vahl from traditional Chinese herbal medicines for its anti-QS activity. Materials and Methods: Anti-QS of F. suspense extracts (FSE) was monitored using the Chromobacterium violaceum 12472 bioassay. Standard methods were used to investigate the effects of FSE on QS-controlled virulence factors production, swimming motility, and biofilm establishment in P. aeruginosa PAO1. Results: FSE could obviously inhibit the violacein production in C. violaceum 12472 and also could inhibit quorum sensing–regulated virulence factors production and biofilm formation in P. aeruginosa in a concentration-dependent manner. The elastase activity and pyocyanin production were inhibited at a maximum of 40.97 and 47.58% when P. aeruginosa was grown in the presence of 0.25 g/mL FSE, which can also inhibit swimming motility of P. aeruginosa. The biofilm formation ability was decreased about 72.45% when in PAO1 cultured with the 0.25 g/mL FSE. The results suggested that FSE may be used as an alternative drug to control and handle harmful infections caused by bacterial pathogens based on QS inhibition. SUMMARY Forsythia suspense water extract could obviously inhibit the purple pigment production in C. violaceum 12472Forsythia suspense water extract could inhibit QS-regulated virulence factors production and biofilm formation in P. aeruginosa. Abbreviations used: QS: Quorum sensing, Pseudomonas aeruginosa P. aeruginosa, Forsythia suspense F. suspense, FSE: F. suspense extracts, Chromobacterium violaceum 12472 C. violaceum 12472, AIs: autoinducers, AHLs: N-acyl-homoserinelactones, LB: Luria-Bertani, MICs: Minimum inhibitory concentrations, CFU: Colony-Forming Units, ATCC: American Type Culture Collection

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

2-Aminoacetophenone as a potential breath biomarker for Pseudomonas aeruginosa in the cystic fibrosis lung

PubMed Central

2010-01-01

Background Pseudomonas aeruginosa infections are associated with progressive life threatening decline of lung function in cystic fibrosis sufferers. Growth of Ps. aeruginosa releases a "grape-like" odour that has been identified as the microbial volatile organic compound 2-aminoacetophenone (2-AA). Methods We investigated 2-AA for its specificity to Ps. aeruginosa and its suitability as a potential breath biomarker of colonisation or infection by Solid Phase Micro Extraction and Gas Chromatography-Mass Spectrometry (GC/MS). Results Cultures of 20 clinical strains of Ps. aeruginosa but not other respiratory pathogens had high concentrations of 2-AA in the head space of in vitro cultures when analysed by GC/MS. 2-AA was stable for 6 hours in deactivated glass sampling bulbs but was not stable in Tedlar® bags. Optimisation of GC/MS allowed detection levels of 2-AA to low pico mol/mol range in breath. The 2-AA was detected in a significantly higher proportion of subjects colonised with Ps. aeruginosa 15/16 (93.7%) than both the healthy controls 5/17 (29%) (p < 0.0002) and CF patients not colonised with Ps. aeruginosa 4/13(30.7%) (p < 0.001). The sensitivity and specificity of the 2-AA breath test compared to isolation of Ps. aeruginosa in sputum and/or BALF was 93.8% (95% CI, 67-99) and 69.2% (95% CI, 38-89) respectively. The peak integration values for 2-AA analysis in the breath samples were significantly higher in Ps. aeruginosa colonised subjects (median 242, range 0-1243) than the healthy controls (median 0, range 0-161; p < 0.001) and CF subjects not colonised with Ps. aeruginosa (median 0, range 0-287; p < 0.003) Conclusions Our results report 2-AA as a promising breath biomarker for the detection of Ps. aeruginosa infections in the cystic fibrosis lung. PMID:21054900

The algicidal mechanism of prodigiosin from Hahella sp. KA22 against Microcystis aeruginosa.

PubMed

Yang, Ke; Chen, Qiuliang; Zhang, Danyang; Zhang, Huajun; Lei, Xueqian; Chen, Zhangran; Li, Yi; Hong, Yaling; Ma, Xiaohong; Zheng, Wei; Tian, Yun; Zheng, Tianling; Xu, Hong

2017-08-10

In recent years, Microcystis aeruginosa blooms have occurred throughout the world, causing huge economic losses and destroying aquatic ecosystems. It is necessary to develop effective and ecofriendly methods to control M. aeruginosa blooms. Here, we report a high algicidal activity of prodigiosin (PG) against M. aeruginosa as well as the algicidal mechanism. PG showed high algicidal activity against M. aeruginosa, with a 50% lethal dose (LD 50 ) of 5.87 μg/mL in 72 h. A combination of methods, including propidium iodide and Annexin V-fluorescein staining assays and light and electron microscopy indicated the existence of two modes of cell death with features similar to those in eukaryotic programmed cell death: necrotic-like and apoptotic-like. Biochemical and physiological analyses showed that PG generates reactive oxygen species (ROS), which induce lipid peroxidation, damage the membrane system and destroy the function of the photosystem. A proteomics analysis revealed that many proteins were differentially expressed in response to PG stress and that most of these proteins were involved in important metabolic processes, which may trigger necrotic-like or apoptotic-like cell death. The present study sheds light on the multiple toxicity mechanisms of PG on M. aeruginosa and its potential for controlling the occurrence of M. aeruginosa blooms in lakes.

[Effect of Pseudomonas aeruginosa exometabolites on planktonic and biofilm cultures of Escherichia coli].

PubMed

Kuznetsova, M V; Karpunina, T I; Maslennikova, I L; Nesterova, L Iu; Demakov, V A

2012-01-01

Study the effect of P. aeruginosa exometabolites on planktonic and biofilm cultures of bioluminescent E. coli strain. E. coli K12 TG1 (pF1 lux+ Ap(r)) recombinant bioluminescent strain, P. aeruginosa ATCC 27853 reference strain and 2 nosocomial isolates were used. Pyocyanin and pyoverdin content in supernatant of P. aeruginosa over-night cultures was evaluated according to E. Deziel et al. (2001). Planktonic and biofilm cultures of E. coli were obtained in 96-well plates (LB, statically, 37 degrees C), optical density of plankton, film biomass (OD600, OD580) and bioluminescence in plankton and biofilm were evaluated in microplate reader Infiniti M200 (Tecan, Austria). P. aeruginosa exometabolites increased the duration of lag-phase in E. coli, and short term exposition inhibited luminescence of planktonic cells. These effects are determined by bactericidal action ofpyocyanin and pyoverdin. Supernatants ofover-night cultures of P. aeruginosa inhibit formation of biofilm and disrupt the formed biofilm of E. coli. Effect of pyocyanin and pyoverdin on these processes is not established, other factors may have higher significance. Bioluminescence of E. coli K12 TGI that reflects the energetic status of the cell allows to evaluate and prognose the character of coexistence of P. aeruginosa in combined with E. coli planktonic and biofilm culture.

Current and future therapies for Pseudomonas aeruginosa infection in patients with cystic fibrosis.

PubMed

Smith, Wynne D; Bardin, Emmanuelle; Cameron, Loren; Edmondson, Claire L; Farrant, Katie V; Martin, Isaac; Murphy, Ronan A; Soren, Odel; Turnbull, Andrew R; Wierre-Gore, Natasha; Alton, Eric W; Bundy, Jacob G; Bush, Andrew; Connett, Gary J; Faust, Saul N; Filloux, Alain; Freemont, Paul S; Jones, Andrew L; Takats, Zoltan; Webb, Jeremy S; Williams, Huw D; Davies, Jane C

2017-08-01

Pseudomonas aeruginosa opportunistically infects the airways of patients with cystic fibrosis and causes significant morbidity and mortality. Initial infection can often be eradicated though requires prompt detection and adequate treatment. Intermittent and then chronic infection occurs in the majority of patients. Better detection of P. aeruginosa infection using biomarkers may enable more successful eradication before chronic infection is established. In chronic infection P. aeruginosa adapts to avoid immune clearance and resist antibiotics via efflux pumps, β-lactamase expression, reduced porins and switching to a biofilm lifestyle. The optimal treatment strategies for P. aeruginosa infection are still being established, and new antibiotic formulations such as liposomal amikacin, fosfomycin in combination with tobramycin and inhaled levofloxacin are being explored. Novel agents such as the alginate oligosaccharide OligoG, cysteamine, bacteriophage, nitric oxide, garlic oil and gallium may be useful as anti-pseudomonal strategies, and immunotherapy to prevent infection may have a role in the future. New treatments that target the primary defect in cystic fibrosis, recently licensed for use, have been associated with a fall in P. aeruginosa infection prevalence. Understanding the mechanisms for this could add further strategies for treating P. aeruginosa in future. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Role of Iron Uptake Systems in Pseudomonas aeruginosa Virulence and Airway Infection

PubMed Central

Minandri, Fabrizia; Imperi, Francesco; Frangipani, Emanuela; Bonchi, Carlo; Visaggio, Daniela; Facchini, Marcella; Pasquali, Paolo; Bragonzi, Alessandra

2016-01-01

Pseudomonas aeruginosa is a leading cause of hospital-acquired pneumonia and chronic lung infections in cystic fibrosis patients. Iron is essential for bacterial growth, and P. aeruginosa expresses multiple iron uptake systems, whose role in lung infection deserves further investigation. P. aeruginosa Fe3+ uptake systems include the pyoverdine and pyochelin siderophores and two systems for heme uptake, all of which are dependent on the TonB energy transducer. P. aeruginosa also has the FeoB transporter for Fe2+ acquisition. To assess the roles of individual iron uptake systems in P. aeruginosa lung infection, single and double deletion mutants were generated in P. aeruginosa PAO1 and characterized in vitro, using iron-poor media and human serum, and in vivo, using a mouse model of lung infection. The iron uptake-null mutant (tonB1 feoB) and the Fe3+ transport mutant (tonB1) did not grow aerobically under low-iron conditions and were avirulent in the mouse model. Conversely, the wild type and the feoB, hasR phuR (heme uptake), and pchD (pyochelin) mutants grew in vitro and caused 60 to 90% mortality in mice. The pyoverdine mutant (pvdA) and the siderophore-null mutant (pvdA pchD) grew aerobically in iron-poor media but not in human serum, and they caused low mortality in mice (10 to 20%). To differentiate the roles of pyoverdine in iron uptake and virulence regulation, a pvdA fpvR double mutant defective in pyoverdine production but expressing wild-type levels of pyoverdine-regulated virulence factors was generated. Deletion of fpvR in the pvdA background partially restored the lethal phenotype, indicating that pyoverdine contributes to the pathogenesis of P. aeruginosa lung infection by combining iron transport and virulence-inducing capabilities. PMID:27271740

Pseudomonas aeruginosa ExoU augments neutrophil transepithelial migration.

PubMed

Pazos, Michael A; Lanter, Bernard B; Yonker, Lael M; Eaton, Alex D; Pirzai, Waheed; Gronert, Karsten; Bonventre, Joseph V; Hurley, Bryan P

2017-08-01

Excessive neutrophil infiltration of the lungs is a common contributor to immune-related pathology in many pulmonary disease states. In response to pathogenic infection, airway epithelial cells produce hepoxilin A3 (HXA3), initiating neutrophil transepithelial migration. Migrated neutrophils amplify this recruitment by producing a secondary gradient of leukotriene B4 (LTB4). We sought to determine whether this two-step eicosanoid chemoattractant mechanism could be exploited by the pathogen Pseudomonas aeruginosa. ExoU, a P. aeruginosa cytotoxin, exhibits phospholipase A2 (PLA2) activity in eukaryotic hosts, an enzyme critical for generation of certain eicosanoids. Using in vitro and in vivo models of neutrophil transepithelial migration, we evaluated the impact of ExoU expression on eicosanoid generation and function. We conclude that ExoU, by virtue of its PLA2 activity, augments and compensates for endogenous host neutrophil cPLA2α function, leading to enhanced transepithelial migration. This suggests that ExoU expression in P. aeruginosa can circumvent immune regulation at key signaling checkpoints in the neutrophil, resulting in exacerbated neutrophil recruitment.

CHANGES IN THE MORPHOLOGY AND POLYSACCHARIDE CONTENT OF MICROCYSTIS AERUGINOSA (CYANOBACTERIA) DURING FLAGELLATE GRAZING(1).

PubMed

Yang, Zhou; Kong, Fanxiang; Shi, Xiaoli; Zhang, Min; Xing, Peng; Cao, Huansheng

2008-06-01

To investigate the changes in the morphology and polysaccharide content of Microcystis aeruginosa (Kütz.) Kütz. during flagellate grazing, cultures of M. aeruginosa were exposed to grazing Ochromonas sp. for a period of 9 d under controlled laboratory conditions. M. aeruginosa responded actively to flagellate grazing and formed colonies, most of which were made up of several or dozens of cells, suggesting that flagellate grazing may be one of the biotic factors responsible for colony formation in M. aeruginosa. When colonies were formed, the cell surface ultrastructure changed, and the polysaccharide layer on the surface of the cell wall became thicker. This change indicated that synthesis and secretion of extracellular polysaccharide (EPS) of M. aeruginosa cells increased under flagellate grazing pressure. The contents of soluble extracellular polysaccharide (sEPS), bound extracellular polysaccharide (bEPS), and total polysaccharide (TPS) in colonial cells of M. aeruginosa increased significantly compared with those in single cells. This finding suggested that the increased amount of EPS on the cell surface may play a role in keeping M. aeruginosa cells together to form colonies. © 2008 Phycological Society of America.

Direct evaluation of Pseudomonas aeruginosa biofilm mediators in a chronic infection model.

PubMed

Byrd, Matthew S; Pang, Bing; Hong, Wenzhou; Waligora, Elizabeth A; Juneau, Richard A; Armbruster, Chelsie E; Weimer, Kristen E D; Murrah, Kyle; Mann, Ethan E; Lu, Haiping; Sprinkle, April; Parsek, Matthew R; Kock, Nancy D; Wozniak, Daniel J; Swords, W Edward

2011-08-01

Biofilms contribute to Pseudomonas aeruginosa persistence in a variety of diseases, including cystic fibrosis, burn wounds, and chronic suppurative otitis media. However, few studies have directly addressed P. aeruginosa biofilms in vivo. We used a chinchilla model of otitis media, which has previously been used to study persistent Streptococcus pneumoniae and Haemophilus influenzae infections, to show that structures formed in vivo are biofilms of bacterial and host origin within a matrix that includes Psl, a P. aeruginosa biofilm polysaccharide. We evaluated three biofilm and/or virulence mediators of P. aeruginosa known to affect biofilm formation in vitro and pathogenesis in vivo--bis-(3',5')-cyclic dimeric GMP (c-di-GMP), flagella, and quorum sensing--in a chinchilla model. We show that c-di-GMP overproduction has a positive impact on bacterial persistence, while quorum sensing increases virulence. We found no difference in persistence attributed to flagella. We conclude from these studies that a chinchilla otitis media model provides a means to evaluate pathogenic mediators of P. aeruginosa and that in vitro phenotypes should be examined in multiple infection systems to fully understand their role in disease.

Pseudomonas aeruginosa Biofilm, a Programmed Bacterial Life for Fitness.

PubMed

Lee, Keehoon; Yoon, Sang Sun

2017-06-28

A biofilm is a community of microbes that typically inhabit on surfaces and are encased in an extracellular matrix. Biofilms display very dissimilar characteristics to their planktonic counterparts. Biofilms are ubiquitous in the environment and influence our lives tremendously in both positive and negative ways. Pseudomonas aeruginosa is a bacterium known to produce robust biofilms. P. aeruginosa biofilms cause severe problems in immunocompromised patients, including those with cystic fibrosis or wound infection. Moreover, the unique biofilm properties further complicate the eradication of the biofilm infection, leading to the development of chronic infections. In this review, we discuss the history of biofilm research and general characteristics of bacterial biofilms. Then, distinct features pertaining to each stage of P. aeruginosa biofilm development are highlighted. Furthermore, infections caused by biofilms on their own or in association with other bacterial species ( i.e. , multispecies biofilms) are discussed in detail.

Pseudomonas aeruginosa Airway Infection Recruits and Modulates Neutrophilic Myeloid-Derived Suppressor Cells

PubMed Central

Öz, Hasan H.; Zhou, Benyuan; Voss, Pina; Carevic, Melanie; Schroth, Carolin; Frey, Nina; Rieber, Nikolaus; Hector, Andreas; Hartl, Dominik

2016-01-01

Pseudomonas aeruginosa is an opportunistic pathogen that causes infections mainly in patients with cystic fibrosis (CF) lung disease. Despite innate and adaptive immune responses upon infection, P. aeruginosa is capable of efficiently escaping host defenses, but the underlying immune mechanisms remain poorly understood. Myeloid-derived suppressor cells (MDSCs) are innate immune cells that are functionally characterized by their potential to suppress T- and natural killer (NK)-cell responses. Here we demonstrate, using an airway in vivo infection model, that P. aeruginosa recruits and activates neutrophilic MDSCs, which functionally suppress T-cell responses. We further show that the CF gene defect (CF transmembrane conductance regulator, CFTR) modulates the functionality, but not the recruitment or generation of neutrophilic MDSCs. Collectively, we define a mechanism by which P. aeruginosa airway infection undermines host immunity by modulating neutrophilic MDSCs in vivo. PMID:27965936

Sepsis associated with hematological malignancies: prophylaxis of Pseudomonas aeruginosa sepsis.

PubMed

Sakamoto, M; Saruta, K; Nakazawa, Y; Shindo, N; Maezawa, H; Yoshikawa, K; Yoshida, M; Shiba, K; Sakai, O; Saito, A

1996-02-01

Underlying diseases, pathogenic bacteria, clinical background and outcome were studied during 91 febrile episodes complicated by sepsis in 55 patients with hematological malignancies, who had been admitted to our hospital (Jikei University Kashiwa Hospital) between January 1990 and December 1994. Particularly in patients with P. aeruginosa sepsis, we compared the prophylactic effect of ciprofloxacin (CPFX) alone with that of the combination of polymyxin B (PL-B) plus kanamycin (KM). The major underlying diseases were acute myelocytic leukemia and malignant lymphoma, followed by myelodysplastic syndrome, acute lymphocytic leukemia and chronic myelocytic leukemia. Nearly two-thirds of the pathogenic microorganisms isolated were gram-positive bacteria (including coagulase-negative staphylococci and Staphylococcus aureus); approximately one-quarter were gram-negative bacteria (such as Pseudomonas aeruginosa), and the remainder were fungi. These microorganisms usually induced sepsis when granulocyte counts were decreased. Sepsis was a direct cause of death in about 60% of the patients and P. aeruginosa sepsis had the worst outcome. Oral administration of CPFX was more effective than PL-B plus KM in preventing P. aeruginosa sepsis. The difference in effectiveness might depend on the absorption profile of the drugs.

Extracellular DNA Acidifies Biofilms and Induces Aminoglycoside Resistance in Pseudomonas aeruginosa.

PubMed

Wilton, Mike; Charron-Mazenod, Laetitia; Moore, Richard; Lewenza, Shawn

2016-01-01

Biofilms consist of surface-adhered bacterial communities encased in an extracellular matrix composed of DNA, exopolysaccharides, and proteins. Extracellular DNA (eDNA) has a structural role in the formation of biofilms, can bind and shield biofilms from aminoglycosides, and induces antimicrobial peptide resistance mechanisms. Here, we provide evidence that eDNA is responsible for the acidification of Pseudomonas aeruginosa planktonic cultures and biofilms. Further, we show that acidic pH and acidification via eDNA constitute a signal that is perceived by P. aeruginosa to induce the expression of genes regulated by the PhoPQ and PmrAB two-component regulatory systems. Planktonic P. aeruginosa cultured in exogenous 0.2% DNA or under acidic conditions demonstrates a 2- to 8-fold increase in aminoglycoside resistance. This resistance phenotype requires the aminoarabinose modification of lipid A and the production of spermidine on the bacterial outer membrane, which likely reduce the entry of aminoglycosides. Interestingly, the additions of the basic amino acid L-arginine and sodium bicarbonate neutralize the pH and restore P. aeruginosa susceptibility to aminoglycosides, even in the presence of eDNA. These data illustrate that the accumulation of eDNA in biofilms and infection sites can acidify the local environment and that acidic pH promotes the P. aeruginosa antibiotic resistance phenotype. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Enterobacter sp. I-3, a bio-herbicide inhibits gibberellins biosynthetic pathway and regulates abscisic acid and amino acids synthesis to control plant growth.

PubMed

Radhakrishnan, Ramalingam; Park, Jae-Man; Lee, In-Jung

2016-12-01

Very few bacterial species were identified as bio-herbicides for weed control. The present research was focused to elucidate the plant growth retardant properties of Enterobacter sp. I-3 during their interaction by determining the changes in endogenous photosynthetic pigments, plant hormones and amino acids. The two bacterial isolates I-4-5 and I-3 were used to select the superior bacterium for controlling weed seeds (Echinochloa crus-galli L. and Portulaca oleracea L.) germination. The post-inoculation of I-3 (Enterobacter sp. I-3) significantly inhibited the weeds seed germination than their controls. The mechanism of bacterium induced plant growth reduction was identified in lettuce treated with I-3 bacterium and compared their effects with known chemical herbicide, trinexapac-ethyl (TE). The treatment of I-3 and TE showed a significant inhibitory effect on shoot length, leaf number, leaf length, leaf width, shoot weight, root weight and chlorophyll content in lettuce seedlings. The endogenous gibberellins (GAs) and abscisic acid (ABA) analysis showed that Enterobacter sp. I-3 treated plants had lower levels of GAs (GA 12 , GA 19 , GA 20 and GA 8 ) and GAs/ABA ratio and then, the higher level of ABA when compared to their controls. Indeed, the individual amino acids ie., aspartic acid, glutamic acid, glycine, threonine, alanine, serine, leucine, isoleucine and tyrosine were declined in TE and I-3 exposed plants. Our results suggest that the utilization of Enterobacter sp. I-3 inhibits the GAs pathway and amino acids synthesis in weeds to control their growth can be an alternative to chemical herbicides. Copyright © 2016 Elsevier GmbH. All rights reserved.

Pseudomonas aeruginosa ventilator-associated pneumonia management.

PubMed

Ramírez-Estrada, Sergio; Borgatta, Bárbara; Rello, Jordi

2016-01-01

Ventilator-associated pneumonia is the most common infection in intensive care unit patients associated with high morbidity rates and elevated economic costs; Pseudomonas aeruginosa is one of the most frequent bacteria linked with this entity, with a high attributable mortality despite adequate treatment that is increased in the presence of multiresistant strains, a situation that is becoming more common in intensive care units. In this manuscript, we review the current management of ventilator-associated pneumonia due to P. aeruginosa, the most recent antipseudomonal agents, and new adjunctive therapies that are shifting the way we treat these infections. We support early initiation of broad-spectrum antipseudomonal antibiotics in present, followed by culture-guided monotherapy de-escalation when susceptibilities are available. Future management should be directed at blocking virulence; the role of alternative strategies such as new antibiotics, nebulized treatments, and vaccines is promising.

Tolerance of Pseudomonas aeruginosa in in-vitro biofilms to high-level peracetic acid disinfection.

PubMed

Akinbobola, A B; Sherry, L; Mckay, W G; Ramage, G; Williams, C

2017-10-01

Biofilm has been suggested as a cause of disinfection failures in flexible endoscopes where no lapses in the decontamination procedure can be identified. To test this theory, the activity of peracetic acid, one of the widely used disinfectants in the reprocessing of flexible endoscopes, was evaluated against both planktonic and sessile communities of Pseudomonas aeruginosa. To investigate the ability of P. aeruginosa biofilm to survive high-level peracetic acid disinfection. The susceptibility of planktonic cells of P. aeruginosa and biofilms aged 24, 48, 96, and 192 h to peracetic acid was evaluated by estimating their viability using resazurin viability and plate count methods. The biomass of the P. aeruginosa biofilms was also quantified using Crystal Violet assay. Planktonic cells of P. aeruginosa were treated with 5-30 ppm concentration of peracetic acid in the presence of 3.0 g/L of bovine serum albumin (BSA) for 5 min. Biofilms of P. aeruginosa were also treated with various peracetic acid concentrations (100-3000 ppm) for 5 min. Planktonic cells of P. aeruginosa were eradicated by 20 ppm of peracetic acid, whereas biofilms showed an age-dependent tolerance to peracetic acid, and 96 h biofilm was only eradicated at peracetic acid concentration of 2500 ppm. Ninety-six-hour P. aeruginosa biofilm survives 5 min treatment with 2000 ppm of peracetic acid, which is the working concentration used in some endoscope washer-disinfectors. This implies that disinfection failure of flexible endoscopes might occur when biofilms build up in the lumens of endoscopes. Copyright © 2017. Published by Elsevier Ltd.

Emergence of Carbapenem-Resistant Pseudomonas aeruginosa and Acinetobacter baumannii Clinical Isolates Collected from Some Libyan Hospitals.

PubMed

Mathlouthi, Najla; Areig, Zaynab; Al Bayssari, Charbel; Bakour, Sofiane; Ali El Salabi, Allaaeddin; Ben Gwierif, Salha; Zorgani, Abdulaziz A; Ben Slama, Karim; Chouchani, Chedly; Rolain, Jean-Marc

2015-06-01

The aim of the present study was to investigate the molecular mechanism of carbapenem resistance in Pseudomonas aeruginosa and Acinetobacter baumannii clinical isolates recovered from Libyan hospitals between April 2013 and April 2014. In total, 49 strains (24 P. aeruginosa and 25 A. baumannii) were isolated, including 21 P. aeruginosa and 22 A. baumannii isolates (87.75%) resistant to imipenem (minimum inhibitory concentrations ≥16 μg/ml). The blaVIM-2 gene was detected in 19 P. aeruginosa isolates. All imipenem-resistant P. aeruginosa isolates showed the presence of OprD mutations. Acquired OXA-carbapenemase-encoding genes were present in all A. baumannii isolates: blaOXA-23 (n=19) and blaOXA-24 (n=3). Finally, a total of 13 and 17 different sequence types were assigned to the 21 P. aeruginosa and the 22 A. baumannii carbapenem-resistant isolates, respectively. This study is the first report describing imipenem-resistant P. aeruginosa and A. baumannii isolated from patients in Libya. We report the first case of co-occurrence of blaVIM-2 with oprD porin loss in identical isolates of P. aeruginosa in Libya and demonstrate that these oprD mutations can be used as a tool to study the clonality in P. aeruginosa isolates. We also report the first identification of multidrug-resistant A. baumannii isolates harboring blaOXA-23-like, blaOXA-24-like, and blaOXA-48-like genes in Libya.

Strain- and Substrate-Dependent Redox Mediator and Electricity Production by Pseudomonas aeruginosa.

PubMed

Bosire, Erick M; Blank, Lars M; Rosenbaum, Miriam A

2016-08-15

Pseudomonas aeruginosa is an important, thriving member of microbial communities of microbial bioelectrochemical systems (BES) through the production of versatile phenazine redox mediators. Pure culture experiments with a model strain revealed synergistic interactions of P. aeruginosa with fermenting microorganisms whereby the synergism was mediated through the shared fermentation product 2,3-butanediol. Our work here shows that the behavior and efficiency of P. aeruginosa in mediated current production is strongly dependent on the strain of P. aeruginosa We compared levels of phenazine production by the previously investigated model strain P. aeruginosa PA14, the alternative model strain P. aeruginosa PAO1, and the BES isolate Pseudomonas sp. strain KRP1 with glucose and the fermentation products 2,3-butanediol and ethanol as carbon substrates. We found significant differences in substrate-dependent phenazine production and resulting anodic current generation for the three strains, with the BES isolate KRP1 being overall the best current producer and showing the highest electrochemical activity with glucose as a substrate (19 μA cm(-2) with ∼150 μg ml(-1) phenazine carboxylic acid as a redox mediator). Surprisingly, P. aeruginosa PAO1 showed very low phenazine production and electrochemical activity under all tested conditions. Microbial fuel cells and other microbial bioelectrochemical systems hold great promise for environmental technologies such as wastewater treatment and bioremediation. While there is much emphasis on the development of materials and devices to realize such systems, the investigation and a deeper understanding of the underlying microbiology and ecology are lagging behind. Physiological investigations focus on microorganisms exhibiting direct electron transfer in pure culture systems. Meanwhile, mediated electron transfer with natural redox compounds produced by, for example, Pseudomonas aeruginosa might enable an entire microbial

Glycan involvement in the adhesion of Pseudomonas aeruginosa to tears.

PubMed

Kautto, Liisa; Nguyen-Khuong, Terry; Everest-Dass, Arun; Leong, Andrea; Zhao, Zhenjun; Willcox, Mark D P; Packer, Nicolle H; Peterson, Robyn

2016-04-01

The human eye is constantly bathed by tears, which protect the ocular surface via a variety of mechanisms. The O-linked glycans of tear mucins have long been considered to play a role in binding to pathogens and facilitating their removal in the tear flow. Other conjugated glycans in tears could similarly contribute to pathogen binding and removal but have received less attention. In the work presented here we assessed the contribution of glycan moieties, in particular the protein attached N-glycans, presented by the broad complement of tear proteins to the adhesion of the opportunistic pathogen Pseudomonas aeruginosa, a leading cause of microbial keratitis and ulceration of the cornea. Our adhesion assay involved immobilising the macromolecular components of tears into the wells of a polyvinyl difluoride (PVDF) microtitre filter plate and probing the binding of fluorescently labelled bacteria. Three P. aeruginosa strains were studied: a cytotoxic strain (6206) and an invasive strain (6294) from eye infections, and an invasive strain (320) from a urinary tract infection (UTI). The ocular isolates adhered two to three times more to human tears than to human saliva or porcine gastric mucin, suggesting ocular niche-specific adaptation. Support for the role of the N-glycans carried by human tear proteins in the binding and removal of P. aeruginosa from the eye was shown by: 1) pre-incubation of the bacteria with free component sugars, galactose, mannose, fucose and sialyl lactose (or combination thereof) inhibiting adhesion of all the P. aeruginosa strains to the immobilised tear proteins, with the greatest inhibition of binding of the ocular cytotoxic 6206 and least for the invasive 6294 strain; 2) pre-incubation of the bacteria with N-glycans released from the commercially available human milk lactoferrin, an abundant protein that carries N-linked glycans in tears, inhibiting the adhesion to tears of the ocular bacteria by up to 70%, which was significantly more

Prevalence of genomic island PAPI-1 in clinical isolates of Pseudomonas aeruginosa in Iran.

PubMed

Sadeghifard, Nourkhoda; Rasaei, Seyedeh Zahra; Ghafourian, Sobhan; Zolfaghary, Mohammad Reza; Ranjbar, Reza; Raftari, Mohammad; Mohebi, Reza; Maleki, Abbas; Rahbar, Mohammad

2012-03-01

Pseudomonas aeruginosa, a gram-negative rod-shaped bacterium, is an opportunistic pathogen, which causes various serious diseases in humans and animals. The aims of this study were to evaluate of the presence of genomic island PAPI-1 in Pseudomonas aeruginosa isolated from Reference Laboratory of Ilam, Milad Hospital and Emam Khomeini Hospital, Iran and to study the frequency of extended spectrum beta-lactamases (ESBLs) among isolates. Forty-eight clinical isolates of P. aeruginosa were obtained during April to September 2010, and were evaluated for ESBLs by screening and confirmatory disk diffusion methods and PAPI-1 by PCR. Fifteen of 48 P. aeruginosa isolates were positive for ESBLs and 17 isolates positive for PAPI-1. This was first study of the prevalence of PAPI-1 in clinical isolates of P. aeruginosa in Iran, showing that most of PAPI-1 positive strains had high levels of antibiotic resistance and produced ESBLs.

LED array designing and its bactericidal effect researching on Pseudomonas aeruginosa in vitro

NASA Astrophysics Data System (ADS)

Fang, Jing; Xing, Jin; Gao, Liucun; Shen, Benjian; Kang, Hongxiang; Jie, Liang; Peng, Chen

2015-10-01

Lights with some special waveband and output power density have a bactericidal effect to some special bacteria. In this paper, the bactericidal effect of light at wavelength of 470 nm on P. aeruginosa (ATCC 27853) is researched with different irradiation dose. The light source is a LED array which is obtained by incoherent combine of 36 LEDs with emitting wavelength of 470 nm. The P. aeruginosa suspension is exposed with the LED array at the light power density of 100 mW/cm2 with exposures time of 0, 5, 10, 20, 40, and 80 min, respectively. The numbers of CFU are then determined by serial dilutions on LB agar plates. The bactericidal effect research results of 470 nm LED on P. aeruginosa show that the killing ratio increases with increasing of the exposure time. For the 80 min irradiation, as much as 92.4% reduction of P. aeruginosa is achieved. The results indicate that, in vitro, 470-nm lights produce dose dependent bactericidal effects on P. aeruginosa.

Pseudomonas aeruginosa genotypes acquired by children with cystic fibrosis by age 5-years.

PubMed

Kidd, Timothy J; Ramsay, Kay A; Vidmar, Suzanna; Carlin, John B; Bell, Scott C; Wainwright, Claire E; Grimwood, Keith

2015-05-01

We describe Pseudomonas aeruginosa acquisitions in children with cystic fibrosis (CF) aged ≤5-years, eradication treatment efficacy, and genotypic relationships between upper and lower airway isolates and strains from non-CF sources. Of 168 CF children aged ≤5-years in a bronchoalveolar lavage (BAL)-directed therapy trial, 155 had detailed microbiological results. Overall, 201/271 (74%) P. aeruginosa isolates from BAL and oropharyngeal cultures were available for genotyping, including those collected before and after eradication therapy. Eighty-two (53%) subjects acquired P. aeruginosa, of which most were unique strains. Initial eradication success rate was 90%, but 36 (44%) reacquired P. aeruginosa, with genotypic substitutions more common in BAL (12/14) than oropharyngeal (3/11) cultures. Moreover, oropharyngeal cultures did not predict BAL genotypes reliably. CF children acquire environmental P. aeruginosa strains frequently. However, discordance between BAL and oropharyngeal strains raises questions over upper airway reservoirs and how to best determine eradication in non-expectorating children. Copyright © 2014 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

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.

[Immunization with Bifidobacterium bifidum-vectored OprI vaccine of Pseudomonas aeruginosa enhances inhibitory effect on P. aeruginosa in mice].

PubMed

Liu, Xiao; Li, Wengui

2017-08-01

Objective To study the pulmonary bacterial loads, splenocyte proliferation, distributions of T cell subsets and cell apoptosis in mice immunized with Bifidobacterium bifidum-vectored OprI (Bb-OprI) vaccine of Pseudomonas aeruginosa and challenged with P. aeruginosa PA01 strain. Methods BALB/c mice were immunized with 5×10 9 CFUs of vaccine by intragastric administration, 3 times a week for 3 weeks, and challenged intranasally with 5×10 6 CFUs of PA01 strain at the fourth week after the first immunization. At the second week after the challenge, all mice were sacrificed to separate their lungs and spleens, and the pulmonary bacterial loads were counted. The proliferation of the splenocytes was determined by MTT assay. The splenic CD4 + , CD8 + T cell subsets and the apoptotic rate of splenocytes were detected by flow cytometry. Results The number of pulmonary bacterial colonies in the mice immunized with the vaccine and challenged with PA01 strain decreased, while the proliferation of splenocytes and the proportion of CD4 + T cells markedly increased, and the apoptosis of splenocytes was notably reduced. Conclusion The intragastric vaccination of recombinant Bb-OprI vaccine can increase the proportion of CD4 + T cells and enhance the inhibitory effect on P. aeruginosa.

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.

Inhaled Colistin in Patients with Bronchiectasis and Chronic Pseudomonas aeruginosa Infection

PubMed Central

Foweraker, Juliet E.; Wilkinson, Peter; Kenyon, Robert F.; Bilton, Diana

2014-01-01

Rationale: Chronic infection with Pseudomonas aeruginosa is associated with an increased exacerbation frequency, a more rapid decline in lung function, and increased mortality in patients with bronchiectasis. Objectives: To perform a randomized placebo-controlled study assessing the efficacy and safety of inhaled colistin in patients with bronchiectasis and chronic P. aeruginosa infection. Methods: Patients with bronchiectasis and chronic P. aeruginosa infection were enrolled within 21 days of completing a course of antipseudomonal antibiotics for an exacerbation. Participants were randomized to receive colistin (1 million IU; n = 73) or placebo (0.45% saline; n = 71) via the I-neb twice a day, for up to 6 months. Measurements and Main Results: The primary endpoint was time to exacerbation. Secondary endpoints included time to exacerbation based on adherence recorded by the I-neb, P. aeruginosa bacterial density, quality of life, and safety parameters. All analyses were on the intention-to-treat population. Median time (25% quartile) to exacerbation was 165 (42) versus 111 (52) days in the colistin and placebo groups, respectively (P = 0.11). In adherent patients (adherence quartiles 2–4), the median time to exacerbation was 168 (65) versus 103 (37) days in the colistin and placebo groups, respectively (P = 0.038). P. aeruginosa density was reduced after 4 (P = 0.001) and 12 weeks (P = 0.008) and the St. George’s Respiratory Questionnaire total score was improved after 26 weeks (P = 0.006) in the colistin versus placebo patients, respectively. There were no safety concerns. Conclusions: Although the primary endpoint was not reached, this study shows that inhaled colistin is a safe and effective treatment in adherent patients with bronchiectasis and chronic P. aeruginosa infection. Clinical trial registered with http://www.isrctn.org/ (ISRCTN49790596) PMID:24625200

Emerging role of lipid droplets in Aedes aegypti immune response against bacteria and Dengue virus

PubMed Central

Barletta, Ana Beatriz Ferreira; Alves, Liliane Rosa; Nascimento Silva, Maria Clara L.; Sim, Shuzhen; Dimopoulos, George; Liechocki, Sally; Maya-Monteiro, Clarissa M.; Sorgine, Marcos H. Ferreira

2016-01-01

In mammals, lipid droplets (LDs) are ubiquitous organelles that modulate immune and inflammatory responses through the production of lipid mediators. In insects, it is unknown whether LDs play any role during the development of immune responses. We show that Aedes aegypti Aag2 cells – an immune responsive cell lineage – accumulates LDs when challenged with Enterobacter cloacae, Sindbis, and Dengue viruses. Microarray analysis of Aag2 challenged with E.cloacae or infected with Dengue virus revealed high transcripts levels of genes associated with lipid storage and LDs biogenesis, correlating with the increased LDs numbers in those conditions. Similarly, in mosquitoes, LDs accumulate in midgut cells in response to Serratia marcescens and Sindbis virus or when the native microbiota proliferates, following a blood meal. Also, constitutive activation of Toll and IMD pathways by knocking-down their respective negative modulators (Cactus and Caspar) increases LDs numbers in the midgut. Our results show for the first time an infection-induced LDs accumulation in response to both bacterial and viral infections in Ae. Aegypti, and we propose a role for LDs in mosquito immunity. These findings open new venues for further studies in insect immune responses associated with lipid metabolism. PMID:26887863

Outbreak of Pseudomonas aeruginosa folliculitis associated with a swimming pool inflatable.

PubMed Central

Tate, D.; Mawer, S.; Newton, A.

2003-01-01

On 18 February 2002, the Communicable Disease Unit was notified by the local Public Health Service Laboratory of a child with a positive skin swab for Pseudomonas aeruginosa. This child had attended the local swimming pool and played on an inflatable, subsequently presenting to a Primary Care Nurse Practitioner with folliculitis. A total of 35 cases was identified during the outbreak. This paper describes a case-control study and microbiological sampling of the cases, the suspected inflatable and a survey of 10 swimming pool inflatables in the local area. The odds ratio for developing folliculitis following use of the inflatable was 12 (95% CI 1.05-136.80). The strain of P. aeruginosa found on the inflatable was identical to that obtained from skin swabs of cases. Nine of 10 (90%) of the inflatables sampled were colonized by P. aeruginosa. Attention should be given to the problem of routine decontamination of swimming pool inflatables. P. aeruginosa folliculitis needs to be considered in the differential diagnosis of skin rashes in children, especially in Primary Care. PMID:12729186

Molecular Epidemiology of a Pseudomonas aeruginosa Hospital Outbreak Driven by a Contaminated Disinfectant-Soap Dispenser

PubMed Central

Lanini, Simone; D'Arezzo, Silvia; Puro, Vincenzo; Martini, Lorena; Imperi, Francesco; Piselli, Pierluca; Montanaro, Marco; Paoletti, Simonetta; Visca, Paolo; Ippolito, Giuseppe

2011-01-01

Background and Objective Pseudomonas aeruginosa infection represents a main cause of morbidity and mortality among immunocompromised patients. This study describes a fatal epidemic of P. aeruginosa that occurred in a hematology unit in Italy. Methods Retrospective cohort study, prospective surveillance, auditing, extensive testing on healthcare workers and environmental investigation were performed to define the dynamics and potential causes of transmission. RAPD, macrorestriction analyses and sequence typing were used to define relationships between P. aeruginosa isolates. Results Eighteen cases of infection were identified in the different phases of the investigation. Of these, five constitute a significant molecular cluster of infection. A P. aeruginosa strain with the same genetic fingerprint and sequence type (ST175) as clinical isolates strain was also isolated from a heavily contaminated triclosan soap dispenser. Discussion and Conclusions Our results are consistent with the hypothesis that patients became indirectly infected, e.g., during central venous catheter handling through contaminated items, and that the triclosan soap dispenser acted as a common continuous source of P. aeruginosa infection. Since P. aeruginosa is intrinsically unsusceptible to triclosan, the use of triclosan-based disinfectant formulations should be avoided in those healthcare settings hosting patients at high risk of P. aeruginosa infection. PMID:21359222

Cloning and characterization of newly isolated lipase from Enterobacter sp. Bn12.

PubMed

Farrokh, Parisa; Yakhchali, Bagher; Karkhane, Ali Asghar

2014-01-01

A mesophilic Enterobacter sp. Bn12 producing an alkaline thermostable lipase was isolated from soil in Tehran, Iran. The lipase gene (ELBn12) was identified from a genomic library. Sequence analysis of the DNA fragment revealed an open reading frame of 879 bp encoding a lipase with a molecular mass of 31.3 kDa. The deduced amino acid sequence showed 96% identity with a lipase of Enterobacter sp. Ag1 and the identity of their DNA sequences was 88.9%. ELBn12 belongs to the lipase subfamily I.1 and its catalytic triad consists of Ser82, Asp237 and His259. The lipase was expressed in Escherichia coli (BL21) pLysS and partially purified by anion exchange chromatography. The maximum activity of ELBn12 was obtained at temperature of 60 °C and pH 8.0 towards tricaprylin (C8) and its specific activity was around 2900 U/mg. ELBn12 was stable within a broad pH range from 6.0 to 11.0. The enzyme showed high stability in both polar and nonpolar organic solvents at 50% (v/v). The lipase activity was enhanced in the presence of 10 mM of Ca(2+), Mg(2+) and K(+), while heavy metals (Fe(3+) and Zn(2+)) had strong inhibitory effect. ELBn12 showed high activity in the presence of 1% (w/v) nonionic surfactants, however ionic surfactants inhibited the lipolytic activity. ELBn12 characteristics show that it has a potential to be used in various industrial processes.

Cloning and characterization of newly isolated lipase from Enterobacter sp. Bn12

PubMed Central

Farrokh, Parisa; Yakhchali, Bagher; Karkhane, Ali Asghar

2014-01-01

A mesophilic Enterobacter sp. Bn12 producing an alkaline thermostable lipase was isolated from soil in Tehran, Iran. The lipase gene (ELBn12) was identified from a genomic library. Sequence analysis of the DNA fragment revealed an open reading frame of 879 bp encoding a lipase with a molecular mass of 31.3 kDa. The deduced amino acid sequence showed 96% identity with a lipase of Enterobacter sp. Ag1 and the identity of their DNA sequences was 88.9%. ELBn12 belongs to the lipase subfamily I.1 and its catalytic triad consists of Ser82, Asp237 and His259. The lipase was expressed in Escherichia coli (BL21) pLysS and partially purified by anion exchange chromatography. The maximum activity of ELBn12 was obtained at temperature of 60 °C and pH 8.0 towards tricaprylin (C8) and its specific activity was around 2900 U/mg. ELBn12 was stable within a broad pH range from 6.0 to 11.0. The enzyme showed high stability in both polar and nonpolar organic solvents at 50% (v/v). The lipase activity was enhanced in the presence of 10 mM of Ca2+, Mg2+ and K+, while heavy metals (Fe3+ and Zn2+) had strong inhibitory effect. ELBn12 showed high activity in the presence of 1% (w/v) nonionic surfactants, however ionic surfactants inhibited the lipolytic activity. ELBn12 characteristics show that it has a potential to be used in various industrial processes. PMID:25242958

Isolation and characterization of a novel 2-methyl-4-chlorophenoxyacetic acid-degrading Enterobacter sp. strain SE08.

PubMed

Tan, Lin; Hu, Qiulong; Xiong, Xingyao; Su, Xiaojun; Huang, Yanning; Jiang, Ziwei; Zhou, Qingming; Zhao, Songyi; Zeng, Wei-ai

2013-10-01

A bacterial strain (SE08) capable of utilizing 2-methyl-4-chlorophenoxy acetic acid (MCPA) as the sole carbon and energy source for growth was isolated by continuous enrichment culturing in minimal salt medium (MSM) from a long term MCPA exposed soil. This bacterial strain was identified as Enterobacter sp. based on morphological, physiological and biochemical tests, as well as 16S rRNA sequence analysis. Its ability to degrade MCPA was determined using high performance liquid chromatography. The strain SE08 can tolerate unusually high MCPA concentrations (125-2000mg/L). The influences of culturing factors (initial concentration, pH, and temperature) on the bacterial growth and substrate degradation were studied. The results showed that the optimal MCPA degradation occurred at an MCPA concentration of 500mg/L, 30°C and pH 6.0. Under these conditions, 68.5 percent of MCPA in MSM was degraded by SE08, and the OD600nm reached 0.64 after culturing for 72h. The degradation of MCPA could be enhanced by addition of both carbon and nitrogen sources. At an initial MCPA concentration of 500mg/L, when 5g/L glucose and 2.5g/L yeast extract were added into the MSM media, the MCPA degradation was significantly increased to 83.8 percent, and OD600nm was increased to 1.09 after incubation at 30°C and pH 6.0 for 72h. This is the first study showing that an Enterobacter sp. strain is capable of degrading MCPA, which might provide a new approach for the remediation of MCPA contaminated soil and contribute to the limited knowledge about the function of Enterobacter species. Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.