scholarly journals Štúidium rastu a produkcie biogénnych amínov niektorými mikroorganizmami za modelových podmienok

1999 ◽  
Vol 17 (No. 1) ◽  
pp. 15-21 ◽  
Author(s):  
G. Greif ◽  
M. Greifova ◽  
J. Dvoran ◽  
J. Karovicova ◽  
V. Buchtova
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Klebsiella Pneumoniae ◽  
Specific Growth ◽  
Growth Curves ◽  
Enterobacter Aerogenes ◽  
Lag Phase ◽  
E Coli ◽  
The Family ◽  
Cell Densities

The study was aimed at the growth of selected strains from the family Enterobacteriaceae (Escherichia coli,  Enterobacter aerogenes and Klebsiella pneumoniae) in meat-peptone (MPB) broth and cabbage juice at different cultivation temperatures, and at the production of biogenic amines (cadaverine, putrescine, histamine). Bacterial growth was evaluated on the basis of specific growth rate (IJm) and lag phase (A.) calculated from growth curves. Cadaverine was produced as the first amine in MPB and cabbage juice by all studied st rains at the cultivation temperatures and at Jiving cell densities 10 6 KTJ/cm3. Putrescine was produced by E. coli only in both substrates at the cultivation temperatures. Histamine was produced by E. coli at 18 °C in cabbage juice and by Enterobacter aerogenes  in both substrates at the cultivation temperatures.

Антимікробна резистентність провідних збудників інфекцій сечових шляхів у Києві (Україна)

2017 ◽  
Vol 1 (2) ◽  
pp. 48-60
Author(s):  
A.G. Salmanov ◽  
A.V. Rudenko
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Klebsiella Pneumoniae ◽  
Staphylococcus Epidermidis ◽  
Klebsiella Oxytoca ◽  
Enterobacter Aerogenes ◽  
Enterobacter Cloacae ◽  
Proteus Vulgaris ◽  
Providencia Rettgeri ◽  
E Coli

Мета роботи — вивчити резистентність до антибіотиків бактеріальних збудників інфекцій сечових шляхів (ІСШ), виділених у пацієнтів урологічного стаціонару в м. Києві. Матеріали і методи. Досліджено 1612 штамів бактерій, виділених із сечі хворих з ІСШ (цистит, уретрит, пієлонефрит), госпіталізованих в урологічне відділення ДУ «Інститут урології НАМН України» у м. Києві протягом 2016 р. Серед пацієнтів переважали жінки — 1201 (74,5 %). Вік хворих становив від 17 до 74 років. Для збору даних використано медичну документацію лікарні. Мікробіологічні дослідження виконано у лабораторії мікробіології ДУ «Інститут урології НАМН України». Аналізували результати культурального дослідження зразків сечі, зібраних за наявності клінічних ознак ІСШ. Дослідження клінічного матеріалу та інтерпретацію отриманих результатів проводили загальноприйнятими методами. Вивчено чутливість уропатогенів до 31 антибіотика дискодифузійним методом відповідно до рекомендацій Інституту клінічних та лабораторних стандартів США (Clinical and Laboratory Standards Institute (CLSI)). Результати та обговорення. Аналіз мікробного спектра сечі виявив домінування серед уропатогенів штамів Escherichia coli (32,0 %), Enterococcus faecalis (19,5 %), Klebsiella pneumoniae (10,9 %), Staphylococcus epidermidis (8,9 %), S. haemolyticus (6,5 %) та Pseudomonas aeruginosa (6,4 %). Частка Enterococcus faecium, Enterobacter aerogenes і Streptococcus viridans становила відповідно 2,5, 2,2 і 1,6 %, Enterobacter cloacae, Klebsiella oxytoca, Acinetobacter baumannii, Proteus vulgaris та Providencia rettgeri — менше 1,0 %. У більшості випадків (69,7 %) мікроорганізми виділено у монокультурі, у решті випадків — у мікробних асоціа- ціях. Високу резистентність до тестованих антибіотиків виявили штами E. aerogenes (45,1 %), E. cloacae (45,7 %), E. faecium (40,9 %), E. faecalis (40,7 %), E. coli (39,9 %), P. aeruginosa (34,0 %), K. pneumoniae (28,6 %). Найбільш активними до уропатогенів були іміпенем (E. coli — 87,6 %, P. aeruginosa — 75,7 %, E. cloacae — 67,3 %, E. aerogenes — 72,6 %, K. pneumoniae — 93,2 %), меропенем (E. coli — 89,1 %, P. aeruginosa — 76,7 %, K. pneumoniae — 82,6 %), лефлоцин (E. coli — 74,5 %, ентерококи — 78,7 %, P. aeruginosa — 76,7 %, E. cloacae — 73,9 %, E. aerogenes — 80,4 %, K. pneumoniae — 83,5 %), амоксицилін/клавуланат (ентерококи — 84,6 %), фурагін (ентерококи — 82,6 %), цефоперазон (K. pneumoniae — 89,2 %, P. aeruginosa — 73,8 %), цефтріаксон (K. pneumoniae — 80,1 %). Висновки. Антибіотикорезистентність збудників ІСШ — важлива терапевтична проблема. Найбільшою активністю до уропатогенів характеризуються іміпенем, меропенем, лефлоцин, амоксицилін/ клавуланат, фурагін, цефоперазон, цефтріаксон, які можна розглядати як препарат вибору для призначення стартової терапії ІСШ. Необхідно здійснювати постійний моніторинг за резистентністю до дії антибіотиків. Політику використання антибіотиків у кожному стаціонарі слід визначати залежно від локальних даних щодо резистентності до протимікробних препаратів.

Shellac Formulations To Reduce Epiphytic Survival of Coliform Bacteria on Citrus Fruit Postharvest†

2001 ◽  
Vol 64 (11) ◽  
pp. 1756-1760 ◽  
Author(s):  
RAYMOND G. McGUIRE ◽  
ROBERT D. HAGENMAIER
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Limit Of Detection ◽  
Citrus Fruit ◽  
Enterobacter Aerogenes ◽  
Coliform Bacteria ◽  
Undetectable Level ◽  
Neutral Solution ◽  
E Coli ◽  
Epiphytic Survival

Survival of the coliform bacteria Enterobacter aerogenes and Escherichia coli was monitored in a neutral carboxyme-thylcellulose formulation and in shellac formulations with various pH and concentrations of ethanol and the preservative paraben; populations were subsequently measured from the surface of citrus fruit coated with these formulations. Numbers of the two bacteria increased over 24 h from 106 CFU/ml to approximately 108 CFU/ml in the carboxymethylcellulose solution, but over this time numbers remained little changed in the neutral solution of shellac. The Enterobacter was more tolerant of alcohol over a 3-h period; although its numbers in a shellac solution with 10% ethanol dropped from more than 106 CFU/ml to just over 103 CFU/ml, E. coli and a third species, Klebsiella pneumoniae, declined toward the limit of detection (5 CFU/ml) during this time. The addition of morpholine to increase the formulation pH to 9.0 caused numbers of bacteria to plummet to an undetectable level within 30 to 60 min. On Ruby Red grapefruit and Valencia oranges in storage at 13°C numbers of E. aerogenes and E. coli declined over 2 weeks from 105 CFU/cm2 to less than 2.5 × 101, but most of the loss in numbers occurred within 1 day. Numbers remained significantly less on shellacked fruit compared with those applied in the carboxymethylcellulose coating, and a shellac coating prepared from a pH 9 solution was more toxic to these species than one in which 12% ethanol had been added to the neutral formulation. The addition of the preservative paraben in the basic shellac was further inhibitory.

Comparison of VRB and VRB-2 Agars for Recovery of Stressed Coliforms From Stored Acidified Half-and-Half1

1982 ◽  
Vol 45 (7) ◽  
pp. 584-585 ◽  
Author(s):  
C. L. REBER ◽  
R. T. MARSHALL
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Enterobacter Aerogenes ◽  
Coliform Bacteria ◽  
E Coli ◽  
Culture Viability

Half-and-half was acidified with delta-gluconolactone, inoculated with three species of coliform bacteria, stored for 31 days at 5 °C, and examined for numbers of viable coliforms on VRB and VRB-2 agars. Loss of culture viability was logarithmic with recovery of 50 and 10% of initial numbers on days 7 and 30, respectively. Escherichia coli had significantly more recoverable injured cells than did Enterobacter aerogenes or Klebsiella pneumoniae. As time of storage increased, the proportion of injured to noninjured cells also increased. However, the maximal number of injured cells was on the thirteenth day of storage of E. coli-inoculated product. VRB-2 agar averaged 20% higher in productivity than VRB agar.

scholarly journals Nationwide Study of the Prevalence, Characteristics, and Molecular Epidemiology of Extended-Spectrum-β-Lactamase-Producing Enterobacteriaceae in France

2007 ◽  
Vol 52 (2) ◽  
pp. 786-789 ◽  
Author(s):  
Muriel Galas ◽  
Jean-Winoc Decousser ◽  
Nelly Breton ◽  
Thierry Godard ◽  
Pierre Yves Allouch ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Molecular Epidemiology ◽  
Molecular Analysis ◽  
Enterobacter Aerogenes ◽  
Nationwide Study ◽  
E Coli ◽  
Extended Spectrum ◽  
Prevalent Species

ABSTRACT Among 10,872 isolates of Enterobacteriaceae from a nationwide study of 88 French hospitals in 2005, 169 (1.7%) expressed an extended-spectrum β-lactamase. The most prevalent species were Escherichia coli (48.5%), Enterobacter aerogenes (23.7%), and Klebsiella pneumoniae (14.8%). Molecular analysis underlined the polyclonal spread of CTX-M-expressing E. coli, primarily isolates of the CTX-M-1 subgroup.

Chromosomal replication origins (oriC) of Enterobacter aerogenes and Klebsiella pneumoniae are functional in Escherichia coli

1982 ◽  
Vol 152 (3) ◽  
pp. 983-993
Author(s):  
N E Harding ◽  
J M Cleary ◽  
D W Smith ◽  
J J Michon ◽  
W S Brusilow ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Enterobacter Aerogenes ◽  
Replication Origins ◽  
Chromosomal Dna ◽  
Protein Activity ◽  
Chromosomal Replication ◽  
E Coli ◽  
Dna Replication Origins ◽  
Unc Operon

The chromosomal DNA replication origins (oriC) from two members of the family Enterobacteriaceae, Enterobacter aerogenes and Klebsiella pneumoniae, have been isolated as functional replication origins in Escherichia coli. The origins in the SalI restriction fragments of 17.5 and 10.2 kilobase pairs, cloned from E. aerogenes and K. pneumoniae, respectively, were found to be between the asnA and uncB genes, as are the origins of the E. coli and Salmonella typhimurium chromosomes. Plasmids containing oriC from E aerogenes, K. pneumoniae, and S. typhimurium replicate in the E. coli cell-free enzyme system (Fuller, et al., Proc. Natl. Acad. Sci. U.S.A. 78:7370--7374, 1981), and this replication is dependent on dnaA protein activity. These SalI fragments from E. aerogenes and K. pneumoniae carry a region which is lethal to E. coli when many copies are present. We show that this region is also carried on the E. coli 9.0-kilobase-pair EcoRI restriction fragment containing oriC. The F0 genes of the atp or unc operon, when linked to the unc operon promoter, are apparently responsible for the lethality.

Specific growth rate and not cell density controls the general stress response in Escherichia coli

Microbiology ◽  
2004 ◽  
Vol 150 (6) ◽  
pp. 1637-1648 ◽  
Author(s):  
Julian Ihssen ◽  
Thomas Egli
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Stress Response ◽  
Specific Growth Rate ◽  
Cell Density ◽  
Specific Growth ◽  
Batch Cultures ◽  
General Stress Response ◽  
E Coli ◽  
Density Effects

In batch cultures of Escherichia coli, the intracellular concentration of the general stress response sigma factor RpoS typically increases during the transition from the exponential to the stationary growth phase. However, because this transition is accompanied by complex physico-chemical and biological changes, which signals predominantly elicit this induction is still the subject of debate. Careful design of the growth environment in chemostat and batch cultures allowed the separate study of individual factors affecting RpoS. Specific growth rate, and not cell density or the nature of the growth-limiting nutrient, controlled RpoS expression and RpoS-dependent hydroperoxidase activity. Furthermore, it was demonstrated that the standard E. coli minimal medium A (MMA) is not suitable for high-cell-density cultivation because it lacks trace elements. Previously reported cell-density effects in chemostat cultures of E. coli can be explained by a hidden, secondary nutrient limitation, which points to the importance of medium design and appropriate experimental set-up for studying cell-density effects.

Quantitative relationships for specific growth rates and macromolecular compositions of Mycobacterium tuberculosis, Streptomyces coelicolor A3(2) and Escherichia coli B/r: an integrative theoretical approach

Microbiology ◽  
2004 ◽  
Vol 150 (5) ◽  
pp. 1413-1426 ◽  
Author(s):  
Robert A. Cox
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Mycobacterium Tuberculosis ◽  
Growth Rates ◽  
Specific Growth ◽  
Streptomyces Coelicolor ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
E Coli ◽  
Specific Growth Rates

Further understanding of the physiological states of Mycobacterium tuberculosis and other mycobacteria was sought through comparisons with the genomic properties and macromolecular compositions of Streptomyces coelicolor A3(2), grown at 30 °C, and Escherichia coli B/r, grown at 37 °C. A frame of reference was established based on quantitative relationships observed between specific growth rates (μ) of cells and their macromolecular compositions. The concept of a schematic cell based on transcription/translation coupling, average genes and average proteins was developed to provide an instantaneous view of macromolecular synthesis carried out by cells growing at their maximum rate. It was inferred that the ultra-fast growth of E. coli results from its ability to increase the average number of rRNA (rrn) operons per cell through polyploidy, thereby increasing its capacity for ribosome synthesis. The maximum growth rate of E. coli was deduced to be limited by the rate of uptake and consumption of nutrients providing energy. Three characteristic properties of S. coelicolor A3(2) growing optimally (μ=0·30 h−1) were identified. First, the rate of DNA replication was found to approach the rate reported for E. coli (μ=1·73 h−1); secondly, all rrn operons were calculated to be fully engaged in precursor-rRNA synthesis; thirdly, compared with E. coli, protein synthesis was found to depend on higher concentrations of ribosomes and lower concentrations of aminoacyl-tRNA and EF-Tu. An equation was derived for E. coli B/r relating μ to the number of rrn operons per genome. Values of μ=0·69 h−1 and μ=1·00 h−1 were obtained respectively for cells with one or two rrn operons per genome. Using the author's equation relating the number of rrn operons per genome to maximum growth rate, it is expected that M. tuberculosis with one rrn operon should be capable of growing much faster than it actually does. Therefore, it is suggested that the high number of insertion sequences in this species attenuates growth rate to still lower values.

scholarly journals Optimized expression of Hfq protein increases Escherichia coli growth

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Phuong N. L. VO ◽  
Hyang-Mi LEE ◽  
Jun REN ◽  
Dokyun NA
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Stress Responses ◽  
Bacterial Species ◽  
Expression Level ◽  
Rna Seq ◽  
E Coli ◽  
Network Analyses ◽  
Metabolic Genes ◽  
Cell Densities

AbstractEscherichia coli is a widely used platform for metabolic engineering due to its fast growth and well-established engineering techniques. However, there has been a demand for faster-growing E. coli for higher production of desired substances. Here, to increase the growth of E. coli cells, we optimized the expression level of Hfq protein, which plays an essential role in stress responses. Six variants of the hfq gene with a different ribosome binding site sequence and thereby a different expression level were constructed. When the Hfq expression level was optimized in DH5α, its growth rate was increased by 12.1% and its cell density was also increased by 4.5%. RNA-seq and network analyses revealed the upregulation of stress response genes and metabolic genes, which increases the tolerance against pH changes. When the same strategy was applied to five other E. coli strains (BL21 (DE3), JM109, TOP10, W3110, and MG1655), all their growth rates were increased by 18–94% but not all their densities were increased (− 12 − + 32%). In conclusion, the Hfq expression optimization can increase cell growth rate and probably their cell densities as well. Since the hfq gene is highly conserved across bacterial species, the same strategy could be applied to other bacterial species to construct faster-growing strains.

scholarly journals Four Carbapenem-Resistant Gram-Negative Species Carrying Distinct Carbapenemases in a Single Patient

2014 ◽  
Vol 53 (3) ◽  
pp. 1031-1033 ◽  
Author(s):  
Baixing Ding ◽  
Fupin Hu ◽  
Yang Yang ◽  
Qinglan Guo ◽  
Jinwei Huang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Acinetobacter Baumannii ◽  
Enterobacter Aerogenes ◽  
Single Patient ◽  
Gram Negative ◽  
Content Type ◽  
E Coli ◽  
Carbapenem Resistant

Carbapenem-resistantEscherichia coli,Klebsiella pneumoniae,Enterobacter aerogenes, andAcinetobacter baumanniiwere isolated from a single patient, each producing different carbapenemases (NDM-1, KPC-2, IMP, and OXA-23, respectively). The NDM-1-producingE. colistrain was preceded by a clonally related carbapenem-susceptible strain a month earlier, suggestingin vivoacquisition ofblaNDM-1.

Proteome reallocation in Escherichia coli with increasing specific growth rate

2015 ◽  
Vol 11 (4) ◽  
pp. 1184-1193 ◽  
Author(s):  
Karl Peebo ◽  
Kaspar Valgepea ◽  
Andres Maser ◽  
Ranno Nahku ◽  
Kaarel Adamberg ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Protein Expression ◽  
Specific Growth Rate ◽  
Specific Growth ◽  
Rich Medium ◽  
Metabolic Processes ◽  
E Coli ◽  
Fast Growing

Allocation of protein expression costs between metabolic processes in slow and fast growingE. coliin defined rich medium.

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