scholarly journals Bactericidal activity against Haemophilus influenzae of cerebrospinal fluid of patients given amoxicillin-clavulanic acid.

1987 ◽  
Vol 31 (12) ◽  
pp. 2018-2019 ◽  
Author(s):  
J M Decazes ◽  
A Bure ◽  
M Wolff ◽  
M D Kitzis ◽  
B Pangon ◽  
...  
2007 ◽  
Vol 51 (10) ◽  
pp. 3699-3706 ◽  
Author(s):  
M. Torrico ◽  
L. Aguilar ◽  
N. González ◽  
M. J. Giménez ◽  
O. Echeverría ◽  
...  

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.


2006 ◽  
Vol 50 (7) ◽  
pp. 2487-2492 ◽  
Author(s):  
Yumiko Sanbongi ◽  
Takahisa Suzuki ◽  
Yumi Osaki ◽  
Nami Senju ◽  
Takashi Ida ◽  
...  

ABSTRACT A total of 621 clinical isolates of Haemophilus influenzae collected in Japan between 1995 and 2003 were studied for their susceptibilities to several antimicrobial agents, β-lactamase production, and amino acid substitutions in penicillin-binding protein 3 (PBP 3). Over the four study periods (first period, 1995 to 1996; second period, 1997 to 1998; third period, 2000 to 2001; fourth period, 2002 to 2003), the susceptibilities to β-lactam agents decreased and the incidence of isolates with substitutions at positions 377, 385, 389, 517, and/or 526 in PBP 3 increased from 28.8% to 52.0%. Five hundred seventy-one β-lactamase-nonproducing isolates were grouped into 18 classes, based on the pattern of the five mutations in PBP 3. The Asp526Lys substitution led to 6.0-, 4.3-, 2.4-, and 5.4-fold increases in amoxicillin-clavulanic acid, cefdinir, cefditoren, and faropenem resistance, respectively. PBP 3 with multiple substitutions (Met377Ile, Ser385Thr, and/or Leu389Phe) together with Asp526Lys resulted in increased resistance compared to that for PBP 3 with the Asp526Lys substitution alone. These results indicate that mutations at these five positions increased resistance to most β-lactams. Although a significant change in the prevalence of β-lactamase-producing strains was not observed, the proportions of those possessing both PBP 3 alterations and β-lactamase production have slightly increased (from 1.4% to 5.0%). The ROB-1 β-lactamase was rare, but this is the first report of this β-lactamase in Japan.


2008 ◽  
Vol 52 (8) ◽  
pp. 2760-2766 ◽  
Author(s):  
Silvia García-Cobos ◽  
José Campos ◽  
Emilia Cercenado ◽  
Federico Román ◽  
Edurne Lázaro ◽  
...  

ABSTRACT The susceptibility to 14 antimicrobial agents and the mechanisms of aminopenicillin resistance were studied in 197 clinical isolates of Haemophilus influenzae—109 isolated in 2007 (study group) and 88 isolated in 1997 (control group). Community antibiotic consumption trends were also examined. H. influenzae strains were consecutively isolated from the same geographic area, mostly from respiratory specimens from children and adults. Overall, amoxicillin resistance decreased by 8.4% (from 38.6 to 30.2%). β-Lactamase production decreased by 15.6% (from 33 to 17.4%, P = 0.01), but amoxicillin resistance without β-lactamase production increased by 7.1% (from 5.7 to 12.8%). All β-lactamase-positive isolates were TEM-1, but five different promoter regions were identified, with Pdel being the most prevalent in both years, and Prpt being associated with the highest amoxicillin resistance. A new promoter consisting of a double repeat of 54 bp was detected. Community consumption of most antibiotics decreased, as did the geometric means of their MICs, but amoxicillin-clavulanic acid and azithromycin consumption increased by ca. 60%. For amoxicillin-clavulanic acid, a 14.2% increase in the population with an MIC of 2 to 4 μg/ml (P = 0.02) was observed; for azithromycin, a 21.2% increase in the population with an MIC of 2 to 8 μg/ml (P = 0.0005) was observed. In both periods, the most common gBLNAR (i.e., H. influenzae isolates with mutations in the ftsI gene as previously defined) patterns were IIc and IIb. Community consumption of trimethoprim-sulfamethoxazole decreased by 54%, while resistance decreased from 50 to 34.9% (P = 0.04). Antibiotic resistance in H. influenzae decreased in Spain from 1997 to 2007, but surveillance should be maintained since new forms of resistances may be developing.


Chemotherapy ◽  
1988 ◽  
Vol 34 (3) ◽  
pp. 191-194 ◽  
Author(s):  
E. Yourassowsky ◽  
M.P. van der Linden ◽  
M.J. Lismont ◽  
F. Crokaert ◽  
Y. Glupczynski

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