scholarly journals Ex vivo 12 h bactericidal activity of oral co-amoxiclav (1.125 g) against beta-lactamase-producing Haemophilus influenzae

2001 ◽  
Vol 48 (4) ◽  
pp. 501-506 ◽  
Author(s):  
S. Bronner
Keyword(s):  
Haemophilus Influenzae ◽  
Bactericidal Activity ◽  
Ex Vivo ◽  
Beta Lactamase

scholarly journals Engineered Phage Endolysin Eliminates Gardnerella Biofilm without Damaging Beneficial Bacteria in Bacterial Vaginosis Ex Vivo

Pathogens ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 54
Author(s):  
Christine Landlinger ◽  
Lenka Tisakova ◽  
Vera Oberbauer ◽  
Timo Schwebs ◽  
Abbas Muhammad ◽  
...  
Keyword(s):  
Bacterial Vaginosis ◽  
Bactericidal Activity ◽  
High Selectivity ◽  
Ex Vivo ◽  
Vaginal Microbiome ◽  
Wild Type ◽  
Wild Type Enzyme ◽  
Promising Alternative ◽  
First Time

Bacterial vaginosis is characterized by an imbalance of the vaginal microbiome and a characteristic biofilm formed on the vaginal epithelium, which is initiated and dominated by Gardnerella bacteria, and is frequently refractory to antibiotic treatment. We investigated endolysins of the type 1,4-beta-N-acetylmuramidase encoded on Gardnerella prophages as an alternative treatment. When recombinantly expressed, these proteins demonstrated strong bactericidal activity against four different Gardnerella species. By domain shuffling, we generated several engineered endolysins with 10-fold higher bactericidal activity than any wild-type enzyme. When tested against a panel of 20 Gardnerella strains, the most active endolysin, called PM-477, showed minimum inhibitory concentrations of 0.13–8 µg/mL. PM-477 had no effect on beneficial lactobacilli or other species of vaginal bacteria. Furthermore, the efficacy of PM-477 was tested by fluorescence in situ hybridization on vaginal samples of fifteen patients with either first time or recurring bacterial vaginosis. In thirteen cases, PM-477 killed the Gardnerella bacteria and physically dissolved the biofilms without affecting the remaining vaginal microbiome. The high selectivity and effectiveness in eliminating Gardnerella, both in cultures of isolated strains as well as in clinically derived samples of natural polymicrobial biofilms, makes PM-477 a promising alternative to antibiotics for the treatment of bacterial vaginosis, especially in patients with frequent recurrence.

Bactericidal substance produced by Haemophilus influenzae b

1975 ◽  
Vol 21 (10) ◽  
pp. 1587-1594 ◽  
Author(s):  
R. A. Venezia ◽  
R. G. Robertson
Keyword(s):  
Haemophilus Influenzae ◽  
Bactericidal Activity ◽  
High Speed ◽  
Indicator Strain ◽  
Bacterial Strains ◽  
Small Molecular Weight ◽  
Plaque Test ◽  
Haemophilus Species ◽  
Phage Propagation ◽  
Thermostable Protein

During bacteriophage studies on Haemophilus influenzae, it was observed that encapsulated type b and unencapsulated Rb strains released a bactericidal substance active against types a, c, d, e, and f H. influenzae, non-typable H. influenzae strains, other Haemophilus species, and certain members of the Enterobacteriaceae. The bactericidal activity was assayed by a plaque test utilizing an Rd strain as an indicator lawn and was also demonstrated in mixed broth cultures of a producer strain and an indicator strain. Immediate lysis of sensitive bacteria by the factor was not evident. The factor is sensitive to trypsin but resistant to deoxyribonuclease, treatment with 2-mercaptoethanol, lipase, α-amylase, and heating in a 100 °C water bath for 20 min. The activity is not dependent upon increased Ca2+ or Mg2+ concentration as is necessary for HP1C1 and S2 phage propagation. The bactericidal factor is not pelleted by high-speed centrifugation at 150 000 × g for 6 h. Treatment with ultraviolet light or mitomycin C does not result in observable phage, phage-like particles, or increased bactericidal activity. The bactericidal factor is not a typical small molecular weight "colicin-like" bacteriocin in that it is not inducible, has a wider range of activity, and does not kill by "single-hit" kinetics. On preliminary characterization, it is a thermostable protein toxic to certain bacterial strains.

scholarly journals Influence of TEM-1 β-Lactamase on the Pharmacodynamic Activity of Simulated Total versus Free-Drug Serum Concentrations of Cefditoren (400 Milligrams) versus Amoxicillin-Clavulanic Acid (2,000/125 Milligrams) against Haemophilus influenzae Strains Exhibiting an N526K Mutation in the ftsI Gene

2007 ◽  
Vol 51 (10) ◽  
pp. 3699-3706 ◽  
Author(s):  
M. Torrico ◽  
L. Aguilar ◽  
N. González ◽  
M. J. Giménez ◽  
O. Echeverría ◽  
...  
Keyword(s):  
Haemophilus Influenzae ◽  
Oral Administration ◽  
Clavulanic Acid ◽  
Bactericidal Activity ◽  
Theoretical Calculations ◽  
Point Of View ◽  
Release Formulation ◽  
Extended Release Formulation ◽  
Amoxicillin Clavulanic Acid ◽  
Free Serum

ABSTRACT The aim of this study was to explore bactericidal activity of total and free serum simulated concentrations after the oral administration of cefditoren (400 mg, twice daily [bid]) versus the oral administration of amoxicillin-clavulanic acid extended release formulation (2,000/125 mg bid) against Haemophilus influenzae. A computerized pharmacodynamic simulation was performed, and colony counts and β-lactamase activity were determined over 48 h. Three strains were used: ampicillin-susceptible, β-lactamase-negative ampicillin-resistant (BLNAR) (also resistant to amoxicillin-clavulanic acid) and β-lactamase-positive amoxicillin-clavulanic acid-resistant (BLPACR) strains, with cefditoren MICs of ≤0.12 μg/ml and amoxicillin-clavulanic acid MICs of 2, 8, and 8 μg/ml, respectively. Against the ampicillin-susceptible and BLNAR strains, bactericidal activity (≥3 log10 reduction) was obtained from 6 h on with either total and free cefditoren or amoxicillin-clavulanic acid. Against the BLPACR strain, free cefditoren showed bactericidal activity from 8 h on. In amoxicillin-clavulanic acid simulations the increase in colony counts from 4 h on occurred in parallel with the increase in β-lactamase activity for the BLPACR strain. Since both BLNAR and BLPACR strains exhibited the same MIC, this was due to the significantly lower (P ≤ 0.012) amoxicillin concentrations from 4 h on in simulations with β-lactamase positive versus negative strains, thus decreasing the time above MIC (T>MIC). From a pharmacodynamic point of view, the theoretical amoxicillin T>MIC against strains with elevated ampicillin/amoxicillin-clavulanic acid MICs should be considered with caution since the presence of β-lactamase inactivates the antibiotic, thus rendering inaccurate theoretical calculations. The experimental bactericidal activity of cefditoren is maintained over the dosing interval regardless of the presence of a mutation in the ftsI gene or β-lactamase production.

LACK OF BACTERICIDAL ACTIVITY OF TRIMETHOPRIM-SULFAMETHOXAZOLE AGAINST SOME STRAINS OF HAEMOPHILUS INFLUENZAE TYPE B

1984 ◽  
Vol 3 (6) ◽  
pp. 597
Author(s):  
Tracy L. Gustafson ◽  
Rose A. Kelley ◽  
Robert H. Hutcheson ◽  
William Schaffner ◽  
Sarah H. Sell ◽  
...  
Keyword(s):  
Haemophilus Influenzae ◽  
Bactericidal Activity ◽  
Haemophilus Influenzae Type ◽  
Haemophilus Influenzae Type B ◽  
Type B

scholarly journals In Vitro Activity of Tebipenem, a New Oral Carbapenem Antibiotic, against β-Lactamase-Nonproducing, Ampicillin-Resistant Haemophilus influenzae

2010 ◽  
Vol 54 (9) ◽  
pp. 3970-3973 ◽  
Author(s):  
Kozue Kishii ◽  
Naoko Chiba ◽  
Miyuki Morozumi ◽  
Akiko Ono ◽  
Takashi Ida ◽  
...  
Keyword(s):  
Haemophilus Influenzae ◽  
Bactericidal Activity ◽  
Gene Mutations ◽  
Vitro Activity ◽  
In Vitro Activity ◽  
Oral Antibiotics ◽  
Pcr Identification ◽  
Minimal Concentration ◽  
Carbapenem Antibiotic

ABSTRACT In vitro activity of tebipenem, a new oral carbapenem antibiotic, against clinical Haemophilus influenzae isolates was compared with those of 8 reference agents. Isolates were classified into 6 resistance classes after PCR identification of β-lactamase genes and ftsI gene mutations. For all isolates, the minimal concentration at which 90% of isolates were inhibited was lower for tebipenem than for the reference oral antibiotics, except for cefditoren. Tebipenem also showed excellent bactericidal activity against β-lactamase-nonproducing, ampicillin-resistant isolates.

scholarly journals Pharmacokinetics and Pharmacodynamics of Levofloxacin against Streptococcus pneumoniae and Staphylococcus aureus in Human Skin Blister Fluid

2000 ◽  
Vol 44 (5) ◽  
pp. 1352-1355 ◽  
Author(s):  
Andrej Trampuz ◽  
Markus Wenk ◽  
Zarko Rajacic ◽  
Werner Zimmerli
Keyword(s):  
Staphylococcus Aureus ◽  
Streptococcus Pneumoniae ◽  
Oral Dose ◽  
Human Skin ◽  
Bactericidal Activity ◽  
Ex Vivo ◽  
Blister Fluid ◽  
Pharmacokinetics And Pharmacodynamics ◽  
Skin Blister ◽  
And Staphylococcus Aureus

ABSTRACT The pharmacokinetics of levofloxacin in serum and in skin blister fluid (SBF) was determined for 20 volunteers after a single 500-mg oral dose of levofloxacin. In addition, ex vivo bactericidal activity of SBF against Streptococcus pneumoniae and Staphylococcus aureus was studied. SBF containing levofloxacin and granulocytes killed 5.2 log of Streptococcus pneumoniae bacteria and 2.0 log of Staphylococcus aureus bacteria during a 6-h incubation.

scholarly journals Activities and Postantibiotic Effects of Gemifloxacin Compared to Those of 11 Other Agents againstHaemophilus influenzae and Moraxella catarrhalis

2000 ◽  
Vol 44 (3) ◽  
pp. 633-639 ◽  
Author(s):  
Todd A. Davies ◽  
Linda M. Kelly ◽  
Dianne B. Hoellman ◽  
Lois M. Ednie ◽  
Catherine L. Clark ◽  
...  
Keyword(s):  
Haemophilus Influenzae ◽  
Bactericidal Activity ◽  
Moraxella Catarrhalis ◽  
The Other ◽  
Amoxicillin Clavulanate

ABSTRACT The activity of gemifloxacin against Haemophilus influenzae and Moraxella catarrhalis was compared to those of 11 other agents. All quinolones were very active (MICs, ≤0.125 μg/ml) against 248 quinolone-susceptible H. influenzae isolates (40.7% of which were β-lactamase positive); cefixime (MICs, ≤0.125 μg/ml) and amoxicillin-clavulanate (MICs ≤4.0 μg/ml) were active, followed by cefuroxime (MICs, ≤16.0 μg/ml); azithromycin MICs were ≤4.0 μg/ml. For nine H. influenzae isolates with reduced quinolone susceptibilities, the MICs at which 50% of isolates are inhibited (MIC50s) were 0.25 μg/ml for gemifloxacin and 1.0 μg/ml for the other quinolones tested. All strains had mutations in GyrA (Ser84, Asp88); most also had mutations in ParC (Asp83, Ser84, Glu88) and ParE (Asp420, Ser458), and only one had a mutation in GyrB (Gln468). All quinolones tested were equally active (MICs, ≤0.06 μg/ml) against 50 M. catarrhalis strains; amoxicillin-clavulanate, cefixime, cefuroxime, and azithromycin were very active. Against 10 H. influenzae strains gemifloxacin, levofloxacin, sparfloxacin, and trovafloxacin at 2× the MIC and ciprofloxacin at 4× the MIC were uniformly bactericidal after 24 h, and against 9 of 10 strains grepafloxacin at 2× the MIC was bactericidal after 24 h. After 24 h bactericidal activity was seen with amoxicillin-clavulanate at 2× the MIC for all strains, cefixime at 2× the MIC for 9 of 10 strains, cefuroxime at 4× the MIC for all strains, and azithromycin at 2× the MIC for all strains. All quinolones except grepafloxacin (which was bactericidal against four of five strains) and all ß-lactams at 2× to 4× the MIC were bactericidal against five M. catarrhalis strains after 24 h; azithromycin at the MIC was bactericidal against all strains after 24 h. The postantibiotic effects (PAEs) against four quinolone-susceptible H. influenzae strains were as follows: gemifloxacin, 0.3 to 2.3 h; ciprofloxacin, 1.3 to 4.2 h; levofloxacin, 2.8 to 6.2 h; sparfloxacin, 0.6 to 3.0 h; grepafloxacin, 0 to 2.1 h; trovafloxacin, 0.8 to 2.8 h. At 10× the MIC, no quinolone PAEs were found against the strain for which quinolone MICs were increased. Azithromycin PAEs were 3.7 to 7.3 h.

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