scholarly journals Conjugal transfer of plasmid DNA from Enterococcus faecalis to Escherichia coli in digestive tracts of gnotobiotic mice.

1992 ◽  
Vol 36 (2) ◽  
pp. 502-504 ◽  
Author(s):  
F Doucet-Populaire ◽  
P Trieu-Cuot ◽  
A Andremont ◽  
P Courvalin
Keyword(s):  
Escherichia Coli ◽  
Enterococcus Faecalis ◽  
Plasmid Dna ◽  
Conjugal Transfer ◽  
Gnotobiotic Mice

scholarly journals TEMPERATURE-SENSITIVE MUTANTS FOR THE REPLICATION OF PLASMIDS IN ESCHERICHIA COLI II. PROPERTIES OF HOST AND PLASMID MUTATIONS

Genetics ◽  
1973 ◽  
Vol 74 (1) ◽  
pp. 1-16
Author(s):  
David T Kingsbury ◽  
Donna G Sieckmann ◽  
Donald R Helinski
Keyword(s):  
Escherichia Coli ◽  
Dna Replication ◽  
Cell Growth ◽  
Dna Synthesis ◽  
Plasmid Dna ◽  
Recipient Cell ◽  
Conjugal Transfer ◽  
Temperature Sensitive ◽  
Permissive Temperature ◽  
Group I

ABSTRACT Host mutations in Escherichia coli K12 selected for the temperature-sensitive replication of the bacterial plasmid colicinogenic factor E1 (ColE1) exhibit a pleiotropic effect with respect to the effect of the mutation on other extrachromosomal elements. The mutations also vary with respect to the time of incubation of the cells at 43°C required for complete cessation of COlE1, DNA synthesis. While the synthesis of the bacterial chromosome appears unaffected, supercoiled ColE1 DNA replication stops immediately in some mutants and gradually decreases during several generations of cell growth before stopping in others. Mutations isolated in the ColE1 plasmid resulted in only a gradual cessation of ColE1 DNA synthesis over several generations of cell growth at 43°C. Conjugal transfer of the ColE1 and COlV factors occurs normally in the host mutants when the transfer is carried out at the permissive temperature; however, the presence of a group I mutation in the donor cell prohibited conjugal transfer of either plasmid DNA at 43°C to a normal recipient cell. Similarly, the presence of this mutation in the recipient prevented the establishment of COlE1 or COlV in the mutant recipient cell upon conjugation with a normal donor at 43°C. Various host COlE1, replication mutants carrying either ColE1 or ColE2 were also defective in the mitomycin Cinduced production of colicin E1 or colicin E2 at 43°C. The majority of the host mutations examined exhibited a temperature sensitivity to growth in deoxycholate in addition to the inhibition of plasmid DNA replication, suggesting a membrane alteration in these mutants when grown at the restrictive temperature.

Intergeneric conjugal transfer of plasmid DNA from Escherichia coli to Kitasatospora setae , a bafilomycin B 1 producer

2004 ◽  
Vol 181 (4) ◽  
pp. 294-298 ◽  
Author(s):  
Sun-Uk Choi ◽  
Chang-Kwon Lee ◽  
Yong-Il Hwang ◽  
Hiroshi Kinoshita ◽  
Takuya Nihira
Keyword(s):  
Escherichia Coli ◽  
Plasmid Dna ◽  
Conjugal Transfer

The In vitro Evaluation of the Antimicrobial Activity of Quercus robur L. Methanolic and Aqueous Leaves’ Extracts, from the Algerian High Plateaus Against some Uropathogenic Microbial Strains

2019 ◽  
Vol 18 (5) ◽  
pp. 262-274
Author(s):  
E. Benyagoub ◽  
N. Nabbou ◽  
S. Boukhalkhel ◽  
I. Dehini
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Candida Albicans ◽  
Enterococcus Faecalis ◽  
Fusidic Acid ◽  
Quercus Robur ◽  
Diffusion Method ◽  
Phytochemical Analysis ◽  
Microbial Strains

The medicinal value of the plants is due to their chemical components that bring a definite physiological action on the human body to prevent the diseases. In this work, we investigated the antimicrobial activity of leaves’ extracts of Quercus robur L., collected from the Algerian upper highlands, on ten bacterial strains and one fungal strain known to be pathogenic. First, we performed a qualitative phytochemical analysis, and second, antimicrobial activity tests performed by agar diffusion method (disc and well) with the determination of MIC by broth macro-dilution method. Given the results, it appears that obtained macerates of Quercus robur L. were rich in bioactive phytoconstituents such as alkaloids, anthraquinones, saponins, tannins, and other components. The yield of aqueous and methanolic macerates of leaves was 8.5 ± 1.41 and 22.4 ± 4.36%, respectively. The bacterial resistance was relatively important to several antibiotics, namely, ampicillin, amoxicillin + clavulanic acid for strains of Escherichia coli and Salmonella sp. However, Staphylococcus aureus strains were resistant to fusidic acid, penicillin, and oxacillin; while Enterococcus faecalis was resistant to fusidic acid, penicillin, oxacillin, and ticarcillin. The antibacterial activity of the macerates toward tested microbial strains showed that the aqueous and methanolic macerates of the leaves were proportional to the tested concentration and active not only against Gram-positive and Gram-negative bacteria but also on the fungal species Candida albicans. The estimated MIC for Escherichia coli, Enterococcus faecalis, and Staphylococcus aureus was in the order of 10 mg/mL, which seems more effective than toward Salmonella sp., Klebsiella pneumoniae, Pseudomonas aeruginosa, and Candida albicans which were in the order of 30 mg/mL. These preliminary results confirm that the part of the studied plant had a very good antimicrobial activity that was proportional to the serial concentrations of the tested extracts.

scholarly journals Urinary Excretion and Bactericidal Activities of Gemifloxacin and Ofloxacin after a Single Oral Dose in Healthy Volunteers

2001 ◽  
Vol 45 (12) ◽  
pp. 3524-3530 ◽  
Author(s):  
Christoph K. Naber ◽  
Michaela Hammer ◽  
Martina Kinzig-Schippers ◽  
Christian Sauber ◽  
Fritz Sörgel ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Urinary Tract ◽  
Urinary Excretion ◽  
Enterococcus Faecalis ◽  
Urinary Tract Infections ◽  
Parent Drug ◽  
Oral Dosage ◽  
Tract Infections ◽  
Cumulative Excretion

ABSTRACT In a randomized crossover study, 16 volunteers (8 men, 8 women) received single oral doses of 320 mg of gemifloxacin and 400 mg of ofloxacin on two separate occasions in the fasting state to assess the urinary excretion and urinary bactericidal titers (UBTs) at intervals for up to 144 h. Ofloxacin showed higher concentrations in urine compared with those of gemifloxacin. The median (range) cumulative excretion of gemifloxacin was 29.7% (8.4 to 48.7%) of the parent drug administered, and median (range) cumulative excretion of ofloxacin was 84.3% (46.5 to 95.2%) of the parent drug administered. The UBTs, i.e., the highest twofold dilutions (with antibiotic-free urine as the diluent) of urine that were still bactericidal, were determined for a reference strain and nine uropathogens for which the MICs of gemifloxacin and ofloxacin were as follows:Escherichia coli ATCC 25922, 0.016 and 0.06 μg/ml, respectively; Klebsiella pneumoniae, 0.03 and 0.06 μg/ml, respectively; Proteus mirabilis, 0.125 and 0.125 μg/ml, respectively; Escherichia coli, 0.06 and 0.5 μg/ml, respectively; Pseudomonas aeruginosa, 1 and 4 μg/ml, respectively; Staphylococcus aureus, 0.008 and 0.25 μg/ml, respectively; Enterococcus faecalis, 0.06 and 2 μg/ml, respectively;Staphylococcus aureus, 0.25 and 4 μg/ml, respectively;Enterococcus faecalis, 0.5 and 32 μg/ml, respectively; and Staphylococcus aureus, 2 and 32 μg/ml, respectively. Generally, the UBTs for gram-positive uropathogens were higher for gemifloxacin than for ofloxacin and the UBTs for gram-negative uropathogens were higher for ofloxacin than for gemifloxacin. According to the UBTs, ofloxacin-resistant uropathogens (MICs, ≥4 mg/liter) should also be considered gemifloxacin resistant. Although clinical trials have shown that gemifloxacin is effective for the treatment of uncomplicated urinary tract infections, whether an oral dosage of 320 mg of gemifloxacin once daily is also adequate for the treatment of complicated urinary tract infections has yet to be confirmed.

scholarly journals Plasmid DNA Supercoiling and Gyrase Activity in Escherichia coli Wild-Type and rpoS Stationary-Phase Cells

2003 ◽  
Vol 185 (3) ◽  
pp. 1097-1100 ◽  
Author(s):  
Yazmid Reyes-Domínguez ◽  
Gabriel Contreras-Ferrat ◽  
Jesús Ramírez-Santos ◽  
Jorge Membrillo-Hernández ◽  
M. Carmen Gómez-Eichelmann
Keyword(s):  
Escherichia Coli ◽  
Stationary Phase ◽  
Plasmid Dna ◽  
Bimodal Distribution ◽  
Dna Supercoiling ◽  
Wild Type

ABSTRACT Stationary-phase cells displayed a distribution of relaxed plasmids and had the ability to recover plasmid supercoiling as soon as nutrients became available. Preexisting gyrase molecules in these cells were responsible for this recovery. Stationary-phase rpoS cells showed a bimodal distribution of plasmids and failed to supercoil plasmids after the addition of nutrients, suggesting that rpoS plays a role in the regulation of plasmid topology during the stationary phase.

Inhibition of Escherichia coli Translocation from the Gastrointestinal Tract by Normal Cecal Flora in Gnotobiotic or Antibiotic-Decontaminated Mice

1980 ◽  
Vol 29 (3) ◽  
pp. 1073-1081
Author(s):  
Rodney D. Berg
Keyword(s):  
Escherichia Coli ◽  
Gastrointestinal Tract ◽  
Lymph Nodes ◽  
Bacterial Flora ◽  
Specific Pathogen Free ◽  
Mesenteric Lymph Nodes ◽  
E Coli ◽  
Mesenteric Lymph ◽  
Specific Pathogen ◽  
Gnotobiotic Mice

Escherichia coli C25 maintained population levels of 10 9 to 10 10 per g of cecum and translocated to 100% of the middle mesenteric lymph nodes in gnotobiotic mice monoassociated with E. coli C25. Intragastric inoculation of these mice with the cecal contents from specific-pathogen-free mice reduced the population levels of E. coli C25 to 10 6 per g of cecum and completely inhibited translocation to the mesenteric lymph nodes. Intragastric inoculation with heat-treated, Formalintreated, or filtered cecal contents did not reduce the population levels of E. coli C25 or reduce the incidence of translocation of E. coli C25 to the mesenteric lymph nodes. Thus, viable bacteria apparently are required in the cecal contents inocula to reduce the population levels and the incidence of translocation of E. coli C25. Treatment with streptomycin plus bacitracin decreased the anaerobic bacterial levels in these gnotobiotic mice, allowing increased population levels of E. coli C25 and increased translocation to the mesenteric lymph nodes. E. coli C25 also translocated to the mesenteric lymph nodes of specific-pathogen-free mice treated with streptomycin and bacitracin before colonization with E. coli C25. The high cecal population levels of E. coli C25 in these antibiotic-decontaminated specific-pathogen-free mice apparently overwhelm any barrier to translocation exerted by the immunologically developed lamina propria of the specific-pathogen-free mice. Inoculation of gnotobiotic mice with a cecal flora also reduced the population levels of an indigenous strain of E. coli with a concomitant inhibition of translocation of the indigenous E. coli to the mesenteric lymph nodes. Thus, bacterial antagonism of the gastrointestinal population levels of certain indigenous bacteria, such as E. coli , by other members of the normal bacterial flora appears to be an important defense mechanism confining bacteria to the gastrointestinal tract.

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