scholarly journals Bactericidal activity of cefoperazone with CP-45,899 against large inocula of beta-lactamase-producing Haemophilus influenzae.

1981 ◽  
Vol 20 (1) ◽  
pp. 63-65 ◽  
Author(s):  
P K Yu ◽  
J A Washington
Keyword(s):  
Haemophilus Influenzae ◽  
Bactericidal Activity ◽  
Beta Lactamase

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 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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