Postantibiotic effect of imipenem on Gram-positive and Gram-negative micro-organisms

1986 ◽  
Vol 18 (Supplement_E) ◽  
pp. 47-59 ◽  
Author(s):  
F. Baquero ◽  
E. Culebras ◽  
C. Patrón ◽  
J. C. Pérez-Díaz ◽  
J. C. Medrano ◽  
...  
Keyword(s):  
Postantibiotic Effect ◽  
Gram Positive ◽  
Gram Negative ◽  
Micro Organisms

Streptococcus salivarius Promotes Mucin Putrefaction and Malodor Production by Porphyromonas gingivalis

2006 ◽  
Vol 85 (10) ◽  
pp. 910-914 ◽  
Author(s):  
N. Sterer ◽  
M. Rosenberg
Keyword(s):  
Porphyromonas Gingivalis ◽  
Potential Role ◽  
Oral Microbiota ◽  
Streptococcus Salivarius ◽  
Oral Malodor ◽  
Gram Positive ◽  
Gram Negative ◽  
Sds Page ◽  
Micro Organisms

Although the contribution of the oral microbiota to oral malodor is well-documented, the potential role of Gram-positive micro-organisms is unclear. In the current study, we tested the hypothesis that Gram-positive micro-organisms contribute to malodor production by deglycosylating oral glycoproteins, rendering them susceptible to subsequent proteolysis. To this end, we examined the effect of Streptococcus salivarius on Porphyromonas gingivalis-mediated putrefaction of a model glycoprotein (pig gastric mucin). Malodor was scored by two odor judges, and volatile sulfides were determined with the use of a sulfide monitor. Mucin degradation was followed by electrophoresis on SDS-PAGE. Results showed that the addition of S. salivarius or β-galactosidase promoted mucin degradation and concomitant malodor production. Addition of glycosidic inhibitors (p-APTG and glucose) inhibited this process. These results suggest that Gram-positive micro-organisms such as S. salivarius contribute to oral malodor production by deglycosylating salivary glycoproteins, thus exposing their protein core to further degradation by Gram-negative micro-organisms.

scholarly journals Multistep Resistance Selection and Postantibiotic-Effect Studies of the Antipneumococcal Activity of LBM415 Compared to Other Agents

2006 ◽  
Vol 51 (2) ◽  
pp. 770-773 ◽  
Author(s):  
Klaudia Kosowska-Shick ◽  
Kim L. Credito ◽  
Glenn A. Pankuch ◽  
Bonifacio DeWasse ◽  
Pamela McGhee ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Bacterial Species ◽  
Peptide Deformylase ◽  
Postantibiotic Effect ◽  
Gram Positive ◽  
Gram Negative ◽  
Resistance Selection

ABSTRACT LBM415 is a peptide deformylase inhibitor active against gram-positive bacterial species and some gram-negative species. In multiselection studies, LBM415 had low MICs against all Streptococcus pneumoniae strains tested, regardless of their genotype, and selected resistant clones after 14 to 50 days. MIC increases correlated with changes mostly in the 70GXGXAAXQ77 motif in peptide deformylase. The postantibiotic effect of LBM415 ranged from 0.3 to 1.4 h.

scholarly journals Antimicrobial Application and Assessment of Green Synthesized Silver Nanoparticles Using Aqueous Leaf Extract of Ficus Copiosa

2019 ◽  
Vol 6 (3) ◽  
pp. 06-15
Author(s):  
David Timi ◽  
Subramaniyam Gopalakrishnan ◽  
Macquin Maino
Keyword(s):  
Silver Nanoparticles ◽  
Sem Analysis ◽  
Leaf Extracts ◽  
Gram Positive ◽  
Gram Negative ◽  
Agar Disc ◽  
Diffusion Technique ◽  
Aqueous Leaf Extract ◽  
Micro Organisms ◽  
Green Synthesized Silver Nanoparticles

Plant mediated green-synthesized silver nanoparticles (AgNPs) and the bioactivity on pathogenic micro-organisms is discussed. In the present investigation, aqueous leaf extracts of a medicinal plant, Ficus copiosa was utilized to construct AgNPs. The synthesized AgNPs was characterized by Ultraviolet-visible (UV-vis), Fourier Transform-infrared (FT-IR), X-ray Diffraction (XRD) spectrometer and Scanning Electron Microscopy (SEM) analysis. The phytosynthesized AgNPs exhibited comparable antimicrobial activity with two reference antibiotics against five indicator micro-organisms including two gram-positive (G+) bacteria, two gram-negative (G-) bacteria and a Protozoa (Pz). Study of the minimum inhibition concentration shows the two gram-negative bacteria to be more susceptible to AgNPs than the two gram-positive bacteria. The organisms included in the study are namely, B. Subtilis (G+), S. aureus (G+), E. coli (G-), S. pneumonia (G-) and T. vaginalis (Pz). Agar Disc diffusion technique was employed to assess the efficacy of the silver nanoparticles on the micro-organisms.

scholarly journals Pharmacodynamic properties of BAY 12-8039 on gram-positive and gram-negative organisms as demonstrated by studies of time-kill kinetics and postantibiotic effect.

1997 ◽  
Vol 41 (6) ◽  
pp. 1377-1379 ◽  
Author(s):  
F J Boswell ◽  
J M Andrews ◽  
R Wise
Keyword(s):  
Streptococcus Pyogenes ◽  
Coli Strain ◽  
Postantibiotic Effect ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
Marked Activity ◽  
Gram Negative Organisms ◽  
Time Kill ◽  
Kinetics Of

Time-kill kinetics of BAY 12-8039 were studied at two inocula against three strains each of Bacteroides fragilis, Escherichia coli, Staphylococcus aureus, Haemophilus influenzae, and Streptococcus pyogenes. The postantibiotic effects of BAY 12-8039 were studied on three strains each of E. coli, S. aureus, H. influenzae, Streptococcus pyogenes, and Streptococcus pneumoniae. The pharmacodynamic data demonstrated that BAY 12-8039 has marked activity against gram-positive and gram-negative organisms (under both anaerobic and aerobic conditions) and anaerobes. BAY 12-8039 also exhibited a postantibiotic effect of >1 h for all strains except one E. coli strain.

scholarly journals Postantibiotic Effect of Tigecycline against 14 Gram-Positive Organisms

2008 ◽  
Vol 53 (2) ◽  
pp. 782-784 ◽  
Author(s):  
G. A. Pankuch ◽  
P. C. Appelbaum
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Haemophilus Influenzae ◽  
Acinetobacter Baumannii ◽  
Enterobacter Cloacae ◽  
Postantibiotic Effect ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Negative Organisms

ABSTRACT The in vitro postantibiotic effects (PAEs), postantibiotic sub-MIC effects (PA-SMEs), and sub-MIC effects of tigecycline were determined for 14 gram-positive and gram-negative organisms. The pneumococcal, staphylococcal, and enterococcal PAEs were 1.9 to 5.1, 2.9 to 5.7, and 3.9 to 6.1 h, respectively, and those for Haemophilus influenzae, Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, and Acinetobacter baumannii were 1.1 to 5.0, 1.9 to 2.1, 1.7 to 1.8, 1.0 to 1.7, and 0.7 to 3 h, respectively. The PA-SMEs (four times the MIC) ranged from 6.7 to >11 h for gram-positive organisms and from 2.3 to >11.3 h for gram-negative organisms.

Bacteria and yeasts from lakes on Deception Island

1967 ◽  
Vol 252 (777) ◽  
pp. 199-207 ◽  
Keyword(s):  
Special Care ◽  
Deception Island ◽  
Gram Positive ◽  
Yeast Flora ◽  
Gram Negative ◽  
Temperature Characteristics ◽  
Large Numbers ◽  
Maximum Temperatures ◽  
Micro Organisms ◽  
Gram Positive Cocci

The bacterial and yeast flora of five lakes—Kroner Lake, a meltwater pool, Relict Lake and two unnamed lakes—on Deception Island in Antarctica were examined. During the sampling and isolation, special care was taken to ensure that the micro-organisms never experienced a temperature above 10 °C. Gram-negative, rod-shaped bacteria predominated in all of the lakes; Kroner Lake also contained large numbers of Gram-positive cocci. Yeasts were isolated from three of the lakes. An examination of the temperature characteristics of the predominant micro-organisms from the lakes showed that over three-quarters had optimum temperatures for growth below about 20 °C, while a third had maximum temperatures of about 20 °C. None of the thirty-one bacteria tested fermented lactose, raffinose or sucrose. Two strains fermented glucose, and one each glycerol and salicin. Several of the bacteria from Kroner Lake utilized compounds that may have been produced by the decomposition of algae in the lake.

scholarly journals Gepotidacin (GSK2140944) In Vitro Activity against Gram-Positive and Gram-Negative Bacteria

2017 ◽  
Vol 61 (7) ◽  
Author(s):  
R. K. Flamm ◽  
D. J. Farrell ◽  
P. R. Rhomberg ◽  
N. E. Scangarella-Oman ◽  
H. S. Sader
Keyword(s):  
Postantibiotic Effect ◽  
Gram Positive ◽  
Bacterial Dna ◽  
Gram Negative ◽  
Content Type ◽  
E Coli ◽  
Time Kill ◽  
Synergy Testing ◽  
Potential Use

ABSTRACT Gepotidacin is a first-in-class, novel triazaacenaphthylene antibiotic that inhibits bacterial DNA replication and has in vitro activity against susceptible and drug-resistant pathogens. Reference in vitro methods were used to investigate the MICs and minimum bactericidal concentrations (MBCs) of gepotidacin and comparator agents for Staphylococcus aureus, Streptococcus pneumoniae, and Escherichia coli. Gepotidacin in vitro activity was also evaluated by using time-kill kinetics and broth microdilution checkerboard methods for synergy testing and for postantibiotic and subinhibitory effects. The MIC90 of gepotidacin for 50 S. aureus (including methicillin-resistant S. aureus [MRSA]) and 50 S. pneumoniae (including penicillin-nonsusceptible) isolates was 0.5 μg/ml, and for E. coli (n = 25 isolates), it was 4 μg/ml. Gepotidacin was bactericidal against S. aureus, S. pneumoniae, and E. coli, with MBC/MIC ratios of ≤4 against 98, 98, and 88% of the isolates tested, respectively. Time-kill curves indicated that the bactericidal activity of gepotidacin was observed at 4× or 10× MIC at 24 h for all of the isolates. S. aureus regrowth was observed in the presence of gepotidacin, and the resulting gepotidacin MICs were 2- to 128-fold higher than the baseline gepotidacin MICs. Checkerboard analysis of gepotidacin combined with other antimicrobials demonstrated no occurrences of antagonism with agents from multiple antimicrobial classes. The most common interaction when testing gepotidacin was indifference (fractional inhibitory concentration index of >0.5 to ≤4; 82.7% for Gram-positive isolates and 82.6% for Gram-negative isolates). The postantibiotic effect (PAE) of gepotidacin was short when it was tested against S. aureus (≤0.6 h against MRSA and MSSA), and the PAE–sub-MIC effect (SME) was extended (>8 h; three isolates at 0.5× MIC). The PAE of levofloxacin was modest (0.0 to 2.4 h), and the PAE-SME observed varied from 1.2 to >9 h at 0.5× MIC. These in vitro data indicate that gepotidacin is a bactericidal agent that exhibits a modest PAE and an extended PAE-SME against Gram-positive and -negative bacteria and merits further study for potential use in treating infections caused by these pathogens.

scholarly journals In Vitro Pharmacodynamic Studies of L-749,345 in Comparison with Imipenem and Ceftriaxone against Gram-Positive and Gram-Negative Bacteria

1998 ◽  
Vol 42 (9) ◽  
pp. 2365-2370 ◽  
Author(s):  
Inga Odenholt ◽  
Elisabeth Löwdin ◽  
Otto Cars
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Comparative Studies ◽  
Gram Negative Bacteria ◽  
Postantibiotic Effect ◽  
Gram Positive ◽  
Gram Negative ◽  
Methicillin Resistant ◽  
Gram Negative Organisms

ABSTRACT L-749,345 is a new parenteral carbapenem with a very long half-life similar to that of ceftriaxone. The aim of the present study was to investigate different pharmacodynamic parameters of L-749,345 in comparison with those of ceftriaxone and imipenem. The following studies were performed: (i) comparative studies of the MICs of L-749,345, imipenem, and ceftriaxone for 70 strains of gram-positive and gram-negative bacteria; (ii) comparative studies of the rate of killing of gram-positive and gram-negative bacteria by L-749,345, imipenem, and ceftriaxone; (iii) studies of the postantibiotic effects of L-749,345, imipenem, and ceftriaxone; and (iv) studies of the postantibiotic sub-MIC effects of L-749,345, imipenem, and ceftriaxone. Significantly lower MICs of L-749,345 compared with those of ceftriaxone were found for all gram-negative organisms except Haemophilus influenzae. The MICs of L-749,345 were similar to those of imipenem for all organisms except Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus, for which the MICs of L-749,345 were higher. A concentration-dependent killing of methicillin-resistant S. aureus but not methicillin-susceptible strains was noted for both L-749,345 and imipenem. All three of the investigated drugs exhibited a postantibiotic effect against the gram-positive strains but exhibited no postantibiotic effect against the gram-negative strains.

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