scholarly journals Validation of the mutant selection window hypothesis with fosfomycin against Escherichia coli and Pseudomonas aeruginosa: an in vitro and in vivo comparative study

2016 ◽  
Vol 70 (2) ◽  
pp. 166-173 ◽  
Author(s):  
Ai-jun Pan ◽  
Qing Mei ◽  
Ying Ye ◽  
Hong-ru Li ◽  
Bao Liu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Comparative Study ◽  
Mutant Selection ◽  
Selection Window

scholarly journals Biological Characterization of Endotoxins Released from Antibiotic-Treated Pseudomonas aeruginosa and Escherichia coli

1998 ◽  
Vol 42 (5) ◽  
pp. 1015-1021 ◽  
Author(s):  
Teruo Kirikae ◽  
Fumiko Kirikae ◽  
Shinji Saito ◽  
Kaoru Tominaga ◽  
Hirohi Tamura ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Lipid A ◽  
Biological Activities ◽  
Polymyxin B ◽  
Mitogen Activated Protein Kinase ◽  
No Production ◽  
Endotoxic Activity

ABSTRACT The supernatants taken from Pseudomonas aeruginosa andEscherichia coli cultures in human sera or chemically defined M9 medium in the presence of ceftazidime (CAZ) contained high levels of endotoxin, while those taken from the same cultures in the presence of imipenem (IPM) yielded a very low level of endotoxin. The biological activities of endotoxin in the supernatants were compared with those of phenol water-extracted lipopolysaccharide (LPS). The endotoxin released from the organisms as a result of CAZ treatment (CAZ-released endotoxin) contained a large amount of protein. The protein, however, lacked endotoxic activity, since the endotoxin did not show any in vivo toxic effects in LPS-hyporesponsive C3H/HeJ mice sensitized with d-(+)-galactosamine (GalN) or any activation of C3H/HeJ mouse macrophages in vitro. The activities of CAZ- and IPM-released endotoxin (as assessed by a chromogenicLimulus test) were fundamentally the same as those ofP. aeruginosa LPS, since their regression lines were parallel. The CAZ-released endotoxin was similar to purified LPS with respect to the following biological activities in LPS-responsive C3H/HeN mice and LPS-hyporesponsive C3H/HeJ mice: lethal toxicity in GalN-sensitized mice, in vitro induction of tumor necrosis factor- and NO production by macrophages, and mitogen-activated protein kinase activation in macrophages. The macrophage activation by CAZ-released endotoxin as well as LPS was mainly dependent on the presence of serum factor and CD14 antigen. Polymyxin B blocked the activity. These findings indicate that the endotoxic activity of CAZ-released endotoxin is due primarily to LPS (lipid A).

scholarly journals Influence of Inoculum Size on the Selection of Resistant Mutants of Escherichia coli in Relation to Mutant Prevention Concentrations of Marbofloxacin

2007 ◽  
Vol 51 (11) ◽  
pp. 4163-4166 ◽  
Author(s):  
Aude Ferran ◽  
Véronique Dupouy ◽  
Pierre-Louis Toutain ◽  
Alain Bousquet-Mélou
Keyword(s):  
Escherichia Coli ◽  
Bacterial Population ◽  
Inoculum Size ◽  
Pharmacodynamic Model ◽  
Initial Size ◽  
Mutant Selection ◽  
Selection Window ◽  
Resistant Mutants ◽  
Selection Of

ABSTRACT We demonstrate using an in vitro pharmacodynamic model that the likelihood of selection of Escherichia coli mutants resistant to a fluoroquinolone was increased when the initial size of the bacterial population, exposed to fluoroquinolone concentrations within the mutant selection window, was increased.

scholarly journals Comparative study of the effects of four cephalosporins against Escherichia coli in vitro and in vivo.

1990 ◽  
Vol 34 (10) ◽  
pp. 1932-1937 ◽  
Author(s):  
M L van Ogtrop ◽  
H Mattie ◽  
H F Guiot ◽  
E van Strijen ◽  
A M Hazekamp-van Dokkum ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Comparative Study

Évaluation de l’activité antibactérienne (in vitro) et l’activité antipyrétique (in vivo) de trois organes de Juniperus phoenicea L. de l’Ouest algérien

2019 ◽  
Author(s):  
Y. Soltani ◽  
M.A. Bouzidi ◽  
F. Toumi ◽  
A. Benyamina
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Juniperus Phoenicea ◽  
Toxicité Aiguë ◽  
Effet Antibactérien

L’objectif de cette étude est d’évaluer l’activité antibactérienne (in vitro) et antipyrétique (in vivo) des extraits hydroalcooliques de trois organes (feuilles, rameaux et baies) de Juniperus phoenicea L. Le test de la sensibilité des souches bactériennes (Escherichia coli ATCC25922, Pseudomonas aeruginosa ATCC27853, Staphylococcus aureus ATCC25923, Staphylococcus aureus subsp. aureus ATCC43300) a été évalué vis-à-vis de nos extraits par la méthode de diffusion en milieu gélosé. La toxicité aiguë a été déterminée par la méthode de Lorke. L’hyperthermie chez les souris a été induite par la levure de bière à 20 %. Les résultats montrent que les extraits des feuilles et des rameaux présentent un remarquable effet antibactérien sur les bactéries à Gram+. Le texte de toxicité aiguë révèle que les extraits de trois organes sont considérés comme des substances faiblement toxiques, l’administration intrapéritonéale des extraits hydroalcooliques de trois organes, à différentes doses, réduit significativement l’hyperthermie. Ces résultats supportent, du moins partiellement, certaines indications thérapeutiques traditionnelles de la plante.

scholarly journals In vitro and in vivo activities of LB10522, a new catecholic cephalosporin.

1996 ◽  
Vol 40 (8) ◽  
pp. 1825-1831 ◽  
Author(s):  
M Y Kim ◽  
J I Oh ◽  
K S Paek ◽  
Y Z Kim ◽  
I C Kim ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Proteus Mirabilis ◽  
Klebsiella Oxytoca ◽  
Acinetobacter Calcoaceticus ◽  
Beta Lactamase ◽  
Salmonella Spp

In vitro activity of LB10522 was compared with those of cefpirome, ceftazidime, ceftriaxone, and cefoperazone against clinical isolates. Against gram-positive bacteria, LB10522 was most active among the compounds tested. It was fourfold more active than cefpirome against methicillin-susceptible Staphylococcus aureus and Enterococcus faecalis. LB10522 was highly effective against most members of the family Enterobacteriaceae tested. Ninety percent of isolates of Escherichia coli, Klebsiella oxytoca, Proteus vulgaris, Proteus mirabilis, and Salmonella spp. were inhibited at a concentration of < or = 0.5 micrograms/ml. These activities were comparable to those of cefpirome. Against Pseudomonas aeruginosa, LB10522 with a MIC at which 90% of the isolates are inhibited of 2 micrograms/ml was 16- and 32-fold more active than ceftazidime and ceftazidime against systemic infections caused by Staphylococcus aureus giorgio, Streptococcus pneumoniae III, Pseudomonas aeruginosa 1912E, Escherichia coli 851E, Proteus mirabilis 1315E, Serratia marcescens 1826E, and Acinetobacter calcoaceticus Ac-54. LB10522 was very resistant to hydrolysis by various beta-lactamases such as TEM-3, TEM-7, SHV-1, FEC-1, and P-99. LB10522 did not induce beta-lactamase in Enterobacter cloacae 1194E, although most of the reference cephalosporins acted as inducers of beta-lactamase in this strain. Time-kill study showed that LB10522, at concentrations of two or four times the MIC, had a rapid bactericidal activity against Staphylococcus aureus 6538p, Escherichia coli 851E, and Pseudomonas aeruginosa 1912E.

scholarly journals DL-α-Monofluoromethylputrescine is a potent irreversible inhibitor of Escherichia coli ornithine decarboxylase

1982 ◽  
Vol 204 (3) ◽  
pp. 771-775 ◽  
Author(s):  
A Kallio ◽  
P P McCann ◽  
P Bey
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Ornithine Decarboxylase ◽  
Half Life ◽  
Arginine Decarboxylase ◽  
Biosynthetic Enzyme ◽  
Irreversible Inhibitor ◽  
E Coli

DL-alpha-Monofluoromethylputrescine (compound R.M.I. 71864) is an enzyme-activated irreversible inhibitor of the biosynthetic enzyme ornithine decarboxylase from Escherichia coli. This compound, however, has much less effect in vitro on ornithine decarboxylase obtained from Pseudomonas aeruginosa. These findings are in contrast with those previously found with the substrate analogue DL-alpha-difluoromethylornithine (compound R.M.I. 71782). The K1 of the DL-alpha-monofluoromethylputrescine for the E. coli ornithine decarboxylase is 110 microM, and the half-life (t1/2) calculated for an infinite concentration of inhibitor is 2.1 min. When DL-alpha-monofluoromethylputrescine is used in combination with DL-alpha-difluoromethylarginine (R.M.I. 71897), an irreversible inhibitor of arginine decarboxylase, in vivo in E. coli, both decarboxylase activities are inhibited (greater than 95%) but putrescine levels are only decreased to about one-third of control values and spermidine levels are slightly increased.

scholarly journals Valutazione clinico/morfologica di Amukine Med® e Braunol®, su CVC in spisilicone

2018 ◽  
Vol 23 (2) ◽  
pp. 19-22
Author(s):  
M. Canzi ◽  
P. Coral ◽  
T. Roggio ◽  
L. De Filippo ◽  
G. Panarello
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Sono State ◽  
Sono Stati ◽  
Nello Studio

La gestione infermieristica riveste un ruolo importante per la sopravvivenza dell'accesso vascolare per emodialisi, soprattutto quando per la sua realizzazione sono stati utilizzati materiali protesici etcrologhi. Scopo di questo studio è di valutare in vitro e in vivo gli eventuali effetti collaterali e l'efficacia di due disinfettanti tra i più comunemente usati (ipoclorito di sodio allo 0,057 Amukine Med® e iodopovidone al 10% Braunol®,) per le medicazioni dei cateteri venosi centrali. Lo studio è stato effettuato da gennaio 2003 a gennaio 2004. In tale periodo abbiamo valutato in vitro mediante esame morfologico gli effetti sui cateteri incubati a breve e lungo termine nei 2 disinfettanti e in vivo l'incidenza di reazioni cutanee locali e la positività dell'esame colturale del tampone cutaneo, in 17 malati uremici con “Tesio cat®” Medcomp (spisilicone) come accesso vascolare per emodialisi. Non si sono notate differenze morfologiche significative nello studio in vitro tra i campioni trattati con i due disinfettanti. Il contatto prolungato dello spisilicone con Amukine Med e Braunol anche in ambiente libero non ha determinato alterazioni morfologiche della parete all'esame macro e microscopico. Nello studio in vivo, condotto su due gruppi composti da 10 pazienti nel gruppo Amukine Med e 7 pazienti in quello con Braunol, sono state effettuate 1088 medicazioni (640 con Amukine Med pari al 58,8% medicazioni totali e 448 con Braunol pari al 41,2% medicazioni totali) pari al 40,5% delle sedute dialitiche con ambo le tecniche di disinfezione. Dagli esami colturali (271 tamponi) in 71 casi è stata riportata crescita batterica; 68 Staphilococcus Epidermidis; 2 Escherichia Coli (gruppo Amuchina Med) 1 Pseudomonas Aeruginosa (gruppo Braunol). Negli ultimi 3 casi (1/68 mesi d'esposizione) era presente sepsi locale. Non si sono rilevate differenze nell'incidenza di infezioni locali o di effetti collaterali indotti dai due disinfettanti.

scholarly journals Mutant Selection Window in Levofloxacin and Moxifloxacin Treatments of Experimental Pneumococcal Pneumonia in a Rabbit Model of Human Therapy

2004 ◽  
Vol 48 (5) ◽  
pp. 1699-1707 ◽  
Author(s):  
Delphine Croisier ◽  
Manuel Etienne ◽  
Emilie Bergoin ◽  
Pierre-Emmanuel Charles ◽  
Catherine Lequeu ◽  
...  
Keyword(s):  
Rabbit Model ◽  
Wild Type ◽  
Bacterial Reduction ◽  
Time Curve ◽  
Mutant Selection ◽  
Drug Concentrations ◽  
Selection Window ◽  
Human Therapy

ABSTRACT For some pneumococci the fluoroquinolone MICs are low but the mutant prevention concentrations (MPCs) are high; this difference defines in vitro the mutant selection window (MSW). We investigated in vivo the bacterial reduction and the occurrence of resistant mutants with moxifloxacin (MFX; 400 mg once daily) or levofloxacin (LVX; 500 mg twice daily) in treatments similar to those in humans with experimental pneumonia due to pneumococci (expPP) exhibiting various MICs and MPCs. The MIC/MPC for MFX and LVX and genotypes were as follows: strain 16089, 0.125/0.125 and 0.5/0.5 (wild type); strain MS1A, 0.25/0.25 and 1/2 (efflux); strain MS2A, 0.25/4 and 1.75/28 (parC79); strain MR3B4, 0.25/4 and 2/32 (parC79); strain M16, 0.5/2 and 8/32 (parC83); strain Gyr-1207, 1.5/3 and 8/16 (gyrA); and strain MQ3A, 4/4 and 16/64 (parC and gyrA). Both drugs were efficient with wild type-expPP, but only MFX was efficient with efflux-expPP. No bacterial reduction was observed for parC-expPPs due to mutants observed in 18 to 100% of animals, depending on the strain and the drug tested. These mutants showed unbound area under the concentration-time curve and MICs of from 50 to 164 for MFX. The in vivo pharmacodynamic boundaries of the MSW were different for MFX and LVX. We conclude that, after LVX or MFX treatment, mutants occur in vivo if there is a preexisting parC mutation, since the drug concentrations fall below the MPCs of these strains. Since the MPC determination cannot be routinely determined, these phenotypes or genotypes should be detected by simple tests to guide the therapeutic options.

scholarly journals The transcription factor DNR from Pseudomonas aeruginosa specifically requires nitric oxide and haem for the activation of a target promoter in Escherichia coli

Microbiology ◽  
2009 ◽  
Vol 155 (9) ◽  
pp. 2838-2844 ◽  
Author(s):  
Nicoletta Castiglione ◽  
Serena Rinaldo ◽  
Giorgio Giardina ◽  
Francesca Cutruzzolà
Keyword(s):  
Nitric Oxide ◽  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Consensus Sequence ◽  
Signal Molecules ◽  
Reporter System ◽  
Nucleotide Substitutions ◽  
E Coli

Pseudomonas aeruginosa is a well-known pathogen in chronic respiratory diseases such as cystic fibrosis. Infectivity of P. aeruginosa is related to the ability to grow under oxygen-limited conditions using the anaerobic metabolism of denitrification, in which nitrate is reduced to dinitrogen via nitric oxide (NO). Denitrification is activated by a cascade of redox-sensitive transcription factors, among which is the DNR regulator, sensitive to nitrogen oxides. To gain further insight into the mechanism of NO-sensing by DNR, we have developed an Escherichia coli-based reporter system to investigate different aspects of DNR activity. In E. coli DNR responds to NO, as shown by its ability to transactivate the P. aeruginosa norCB promoter. The direct binding of DNR to the target DNA is required, since mutations in the helix–turn–helix domain of DNR and specific nucleotide substitutions in the consensus sequence of the norCB promoter abolish the transcriptional activity. Using an E. coli strain deficient in haem biosynthesis, we have also confirmed that haem is required in vivo for the NO-dependent DNR activity, in agreement with the property of DNR to bind haem in vitro. Finally, we have shown, we believe for the first time, that DNR is able to discriminate in vivo between different diatomic signal molecules, NO and CO, both ligands of the reduced haem iron in vitro, suggesting that DNR responds specifically to NO.

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