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At least 19 recordsLinked to original sources
PubMed1997

A study of 5-day cefdinir treatment for streptococcal pharyngitis in children. Cefdinir Pediatric Pharyngitis Study Group.

OBJECTIVE: To compare the safety and efficacy of a 5-day regimen of cefdinir with those a conventional 10-day regimen of penicillin V for the treatment of streptococcal pharyngitis in children. DESIGN: Investigator-blind, randomized controlled trial. SETTING: Primary care, ambulatory. PATIENTS: Children aged 1 to 12 years with signs and symptoms of pharyngitis and a positive result on a rapid screening test for Streptococcus pyogenes (ie, a convenience sample). Four hundred eighty-two patients were enrolled in the study, and 440 were clinically and microbiologically evaluable. The most common reasons patients were nonevaluable were failure to return for specified visits and noncompliance with the administration of the medication; 2 patients receiving penicillin V discontinued use of the drug because of adverse events. INTERVENTION: Patients were randomized to receive either 7-mg/kg cefdinir, twice daily, for 5 days or 10-mg/kg penicillin V potassium, 4 times daily, for 10 days. MAIN OUTCOME MEASURES: The eradication of S pyogenes and the clinical cure of the signs and symptoms of pharyngitis, both determined 5 to 10 days after the completion of therapy. RESULTS: Streptococcus pyogenes was eradicated in 201 (90%) of the 224 patients receiving cefdinir and 155 (72%) of the 216 patients receiving penicillin V (95% confidence interval [CI], 10.7%-25.1%; P < .001). The clinical cure rates were 92% and 91% in the groups receiving cefdinir and penicillin V, respectively (95% CI, -4.5% to 6.1%; P = .80). Adverse events, regardless of the opinion of the investigator about their relationship to the study medication, occurred in 12.5% of the patients receiving cefdinir and 13.6% of the patients receiving penicillin V (P = .69). CONCLUSIONS: A 5-day regimen of cefdinir eradicated a higher proportion of S pyogenes than a 10-day regimen of penicillin V. No difference was noted between the regimens for clinical outcomes or adverse event rates.

Adolescent↗
PubMedDate not supplied

Efficacy and safety of cefdinir in the treatment of patients with acute bronchitis. The Cefdinir Bronchitis Study Group.

In this randomized, open-label, dose-comparative study, 18 investigators enrolled 466 patients with acute bronchitis. Patients were randomly assigned to receive either 600 mg of cefdinir once daily (QD) or 300 mg of cefdinir twice daily (BID) for 10 days. Both microbiologic and clinical efficacy were assessed at the test-of-cure visit, 7 to 14 days after therapy stopped. A total of 296 patients were classified as assessable at the test-of-cure visit (n = 150 QD, n = 146 BID). Eradication rates of baseline pathogens in these assessable patients were similar in both groups; the baseline pathogen eradication rate for assessable patients in the QD arm was 92%, and that in the BID arm was 93%. Clinical success (cure or improvement) in assessable patients was 91% and 93%, respectively. No difference was seen in the incidence of adverse events, in the incidence of diarrhea, or in the incidence of treatment withdrawals between the two groups. We conclude that cefdinir is effective and safe for the treatment of patients with acute bronchitis.

Adult↗
PubMed1991

[Pharmacokinetic and clinical studies of cefdinir in the pediatric field. Pediatric Study Group of Cefdinir].

We studied pharmacokinetics and clinical effects of 5% and 10% fine granules of cefdinir (FK 482, CFDN), a new oral cephalosporin, in the pediatric field and the following results were obtained. 1. Pharmacokinetics (blood concentration and urinary excretion) Pharmacokinetics of CFDN in 163 children was investigated. Cmax and T 1/2 were 0.92 +/- 0.45 micrograms/ml and 1.95 +/- 1.06 hours, respectively, in the fasting state, and were 0.63 +/- 0.29 micrograms/ml and 2.26 +/- 0.65 hours, respectively, in the non-fasting state, at a dose level of 3 mg (potency)/kg. At a dose level of 6 mg (potency)/kg, Cmax and T 1/2 were 1.29 +/- 0.49 micrograms/ml and 2.11 +/- 1.85 hours, respectively, in the fasting state and were 1.28 +/- 0.48 micrograms/ml and 2.01 +/- 0.84 hours, respectively, in the non-fasting state. Data of Cmax and AUC showed that blood concentration of the drug depended on dose levels. Urinary recovery rates in the first 8 hours were 20.5 +/- 8.8% in the fasting state and 14.8 +/- 5.9% in the non-fasting at a dose level of 3 mg (potency)/kg and 16.5 +/- 6.7% and 17.8 +/- 2.4%, respectively, at 6 mg (potency)/kg. 2. Clinical effects Clinical effects of CFDN on various infections were studied in 612 children who were treated with 5% fine granules of CFDN (5% granule group) and in 208 with 10% fine granules of CFDN (10% granule group). CFDN granules were administered mainly at daily doses of 9.0-18.0 mg (potency)/kg in 3 divided portions. Clinical efficacy rates in 428 children of the 5% granule group and in 159 of the 10% granule group from whom causative bacteria were isolated, were 94.9% and 96.2%, respectively. The clinical efficacy rates for patients who were responsive to previous antibiotic therapy were 91.2% in the 5% granule group and 100% in the 10% granule group. Bacteriological eradication rate was 82.1% for 491 strains in the 5% granule group, and was 84.0% for 175 strains in the 10% granule group. The incidences of side effects were 3.9% (24/608) in the 5% fine granule group and 5.8% (12/206) in the 10% granule group. All of the side effects were slight gastrointestinal disorders, and no serious side effects were found. As for clinical laboratory test results, slight elevations of eosinophile, platelet or transaminase were observed. Based on the above results, it is considered that the appropriate dose levels of CFDN for pediatric infections ranged from 9.0 to 18.0 mg (potency)/kg a day, divided into 3 portions.

Administration, Oral↗
PubMed1996

Pharmacokinetic interaction between cefdinir and two angiotensin-converting enzyme inhibitors in rats.

The pharmacokinetic interaction between cefdinir and an angiotensin-converting enzyme inhibitor (captopril or quinapril) was investigated in rats. The linearity of cefdinir pharmacokinetics was demonstrated in three groups of rats receiving 10, 20, or 40 mg of cefdinir per kg of body weight intravenously. Then, three other groups of rats were established as follows: group 1 (n = 5) received cefdinir (10 mg/kg) intravenously, and 12 blood samples per rat were drawn between 0 and 8 h after injection of the dose; group 2 (n = 5) was treated in the same way as group 1, but captopril (0.8 mg/kg) was coadministered by intraintestinal injection into all animals; group 3 (n = 6) was treated in the same way as group 2, but quinapril (0.8 mg/kg) replaced captopril. Plasma cefdinir concentrations were measured by liquid chromatography, and the data were analyzed by a noncompartmental method. Finally, three groups of four or five rats each were set up as described above, but the cefdinir dose was 20 mg/kg and the animals were sacrificed 1 h after drug injection to collect blood to determine the unbound cefdinir fraction (fu) by ultrafiltration. The angiotensin-converting enzyme inhibitors increased the mean cefdinir area under the concentration-time curve up to 8 h by a factor of 1.8 (captopril; P < 0.05) and a factor of 3.5 (quinapril; P < 0.05). With captopril, mean cefdinir clearance was decreased by a factor of 2, and the volume of distribution increased by the same factor, while the fu increased from 15.4% +/- 3.0% (cefdinir alone) to 22.8% +/- 10.9% (cefdinir plus captopril). Captopril increased the cefdinir half-life from 0.62 +/- 0.17 to 2.92 +/- 0.95 h. With quinapril, the interaction was so strong that no elimination phase was detectable in four of the six rats, and therefore, no pharmacokinetic parameter values other than the cefdinir fu could be calculated; the cefdinir fu increased to 25.1% +/- 11.1%. It is concluded that captopril and quinapril (and/or their metabolites) have a major impact on the disposition of cefdinir in rats, probably by competition at the plasma protein-binding level and at the tubular anionic carrier level. This latter mechanism should also be relevant in humans.

Angiotensin-Converting Enzyme Inhibitors↗
PubMedDate not supplied

Antibacterial activity of cefpodoxime in comparison with cefixime, cefdinir, cefetamet, ceftibuten, loracarbef, cefprozil, BAY 3522, cefuroxime, cefaclor and cefadroxil.

The new oral cephalosporins cefpodoxime, cefixime, cefdinir, cefetamet and ceftibuten demonstrate enhanced activity against Enterobacteriaceae susceptible to the established compounds as well (e.g. cefuroxime, cefaclor, cefadroxil). In addition, cefpodoxime, cefixime, cefdinir, cefetamet and ceftibuten include in their spectrum species hitherto resistant to oral cephalosporins (Proteus vulgaris, Providencia spp., Yersinia enterocolitica). Besides, the majority of these compounds demonstrate relevant activity (MIC50 equal to or below 2 mg/l) against Enterobacter spp., Citrobacter freundii, Serratia spp. and Morganella morganii. Ceftibuten is the most potent oral cephalosporin against most of the Enterobacteriaceae. Non-fermentative bacilli (Acinetobacter spp., Pseudomonas spp.) remain completely resistant to oral cephalosporins (except some Acinetobacter species against cefdinir and Pseudomonas cepacia against ceftibuten). Antistaphylococcal activity for oral cephalosporins is highest for cefdinir followed by BAY 3522, cefprozil, cefuroxime and cefpodoxime. Loracarbef, cefaclor and cefadroxil are about equally active, while the other compounds are only weakly active (cefixime) or inactive (cefetamet, ceftibuten). Enterococci are insensitive to new generation oral cephalosporins as they have been to established compounds. The most active oral cephalosporins against hemolytic streptococci are cefdinir and cefprozil. Streptococcus pneumoniae, Streptococcus milleri and Streptococcus mitior are most susceptible to cefpodoxime, cefdinir, cefuroxime and BAY 3522. Penicillin resistant pneumococci have to be regarded as resistant to all oral cephalosporins. Fastidious pathogens like Haemophilus spp., Moraxella catarrhalis and Neisseria gonorrhoeae are more susceptible to cefpodoxime, cefixime, cefdinir, cefetamet and ceftibuten than to the other oral cephalosporins. The activity of oral cephalosporins is only weak against Listeria spp., Helicobacter pylori and anaerobic pathogens (except BAY 3522). Bordetella pertussis remains resistant to all absorbable cephalosporins. Progress in antibacterial activity of oral cephalosporins was mainly achieved by cefpodoxime, cefixime, cefdinir, cefetamet and ceftibuten against Enterobacteriaceae and the fastidious pathogens and against staphylococci and the nonenterococcal streptococci by cefdinir, BAY 3522, cefprozil and cefpodoxime.

Bacteria↗
PubMedDate not supplied

In vitro activity evaluations of cefdinir (FK482, CI-983, and PD134393). A novel orally administered cephalosporin.

Cefdinir, a so-called third-generation oral cephalosporin was tested in vitro against over 700 pathogens from patients with bacteremia. Cefdinir was very active against the Enterobacteriaceae with a 50% minimum inhibitory concentration (MIC50) value range of less than or equal to 0.03-8 micrograms/ml. The enteric species having the highest MIC90S (greater than or equal to 16 micrograms/ml) were Citrobacter freundii, and the enterobacters, Morganella morganii, Proteus vulgaris, and Serratia marcescens. Cefdinir was generally two- to fourfold less active than cefixime, but markedly more potent with a wider spectrum compared with older oral cephalosporins, cefaclor or cefuroxime. In contrast to cefixime, cefdinir inhibited Staphylococcus aureus (MIC90, 1 micrograms/ml) and other staphylococci. Pneumococci, beta-hemolytic streptococci, Haemophilus influenzae, Moraxella catarrhalis, and pathogenic Neisseria spp. (MIC90S, 0.12-0.5 micrograms/ml) were cefdinir susceptible, but Pseudomonas aeruginosa, oxacillin-resistant staphylococci and Bacteroides fragilis gr. strains were resistant. Cefdinir was generally bactericidal with a minimal inoculum effect at 10(6) colony-forming units per spot. Cefdinir beta-lactamase hydrolysis by some recently described extended broad spectrum beta-lactamases was suspected. Cefdinir exhibited a wide, balanced spectrum for an oral cephalosporin indicating possible clinical use against susceptible pathogens in respiratory tract, urinary tract, genital and cutaneous infections.

Cefdinir↗
PubMed1993

Impairment of cefdinir absorption by iron ion.

The effect of iron ion on the absorption of cefdinir, a new oral cephalosporin derivative, was evaluated in healthy male volunteers in a randomized three-way crossover study. The subjects received 200 mg cefdinir alone, 200 mg cefdinir and two tablets of iron ion concomitantly, and two tablets of iron ion preparation 3 hours after 200 mg cefdinir administration. The area under the concentration curve [AUC(0-12)] of cefdinir with concurrent iron was significantly smaller than that with cefdinir alone (mean +/- SD, 0.78 +/- 0.38 versus 10.3 +/- 1.35 micrograms.hr/ml). While there were no differences in AUC(0-3) between drug alone and drug with iron 3 hours later, the AUC(3-12) with delayed iron was significantly smaller than that of cefdinir alone (4.60 +/- 1.54 versus 8.03 +/- 1.72 micrograms.hr/ml). These findings suggest that the mechanism of interaction between cefdinir and iron ion preparation is the formation of a chelation complex and that this complex probably restricts gastrointestinal absorption.

Adult↗
PubMed1994

Cefdinir (CI-983), a new oral amino-2-thiazolyl cephalosporin, inhibits human neutrophil myeloperoxidase in the extracellular medium but not the phagolysosome.

Cefdinir, a new oral 2-amino-5-thiazolyl cephalosporin, inhibited the luminol-amplified chemiluminescence (LACL) response of human neutrophils stimulated by PMA but not opsonized zymosan, in a concentration-dependent but not time-dependent manner. The LACL response to opsonized zymosan in cytochalasin B-treated neutrophils was, however, inhibited by cefdinir. Various cephalosporins, regardless of the presence of a 2-amino-5-thiazolyl moiety, did not significantly alter the neutrophil LACL response triggered by PMA and zymosan. The LACL response induced by the calcium ionophore A23187 and FMLP was also impaired by cefdinir, and this impairment was increased in cytochalasin B-treated neutrophils. Superoxide anion generation by neutrophils, measured in terms of lucigenin-amplified chemiluminescence and cytochrome c reduction, was not altered. Spontaneous and FMLP-induced neutrophil degranulation, assessed by lysozyme and beta-glucuronidase release, were not modified by cefdinir. Furthermore, cefdinir inhibited LACL generation in cell-free systems consisting of H2O2, NaI, and either horseradish peroxidase or a myeloperoxidase-containing neutrophil extract. Orthodianisidine oxidation in these two acellular systems was inhibited by cefdinir. Cefdinir did not alter neutrophil bacterial killing at concentrations that inhibited myeloperoxidase-containing neutrophil extract-dependent reactions induced by soluble stimuli. Taken together, these data strongly suggest that cefdinir directly inhibits the activity of myeloperoxidase-containing neutrophil extract released into the extracellular medium during neutrophil stimulation by soluble mediators, but has no effect on that released into the phagolysosome during phagocytosis. This unusual property of a member of the beta-lactam family could be of interest in modulating the exaggerated inflammatory process often associated with infectious diseases.

Blood Bactericidal Activity↗
PubMed1995

Antistaphylococcal activity of cefdinir, a new oral third-generation cephalosporin, alone and in combination with other antibiotics, at supra- and sub-MIC levels.

Cefdinir is one of the few oral third generation cephalosporins that shows useful activity against nosocomial Gram-positive pathogens. For this reason the anti-staphylococcal potency of the new drug, alone or in combination with other drugs was further characterized. Against penicillin-resistant, oxacillin-susceptible Staphylococcus isolates, cefdinir demonstrated useful in-vitro activity. MIC90 values (in mg/L) were 0.25 for Staphylococcus aureus (30 strains), 0.06 for Staphylococcus epidermidis (24), 0.125 for Staphylococcus hominis (10), 0.5 for both Staphylococcus xylosus (15) and Staphylococcus capitis (11) and 4 for Staphylococcus saprophyticus (10), while Staphylococcus haemolyticus (12) was less susceptible with a MIC90 value of 32. Cefdinir activity was not adversely affected by several variables such as pH, inoculum size or the presence of serum or urine. The new cephem induced a PAE on all isolates studied: with S. aureus the extent of regrowth suppression ranged from 0.8 to 1 h, and with the other species from 0.5 (S. epidermidis) to 4.1 h (S. haemolyticus). Development of resistant strains was rare. At the highest level used (10 x MIC) mutants arose with a frequency of 6 x 10(-8) with S. haemolyticus and 2 x 10(-9) with S. epidermidis. The absence of a paradoxical effect of increasing concentrations of cefdinir on its bactericidal activity was confirmed up to a value of 500-fold the MICs. When cefdinir activity was assessed in association with ciprofloxacin, netilmicin, clarithromycin, fosfomycin, rifampicin, teicoplanin and vancomycin using the chequerboard and time-kill techniques, indifference predominated with all strains and in all combinations. Synergism was detected only in 11 out of a total of 175 tests performed by the chequerboard method. Using the time-kill technique cefdinir reacted synergically in 25 of 126 tests. Antagonism was never observed. S. aureus exposed to sub-inhibitory concentrations of cefdinir failed to grow on mannitol-salt agar and to produce haemolysins, but retained coagulase activity. Penicillinase production was also lost in about 17% of the survivors. Hydrophobicity changes were detected in all species tested with the exception of S. saprophyticus.

Anti-Bacterial Agents↗
PubMed1996

In vitro activity of cefdinir against respiratory pathogens isolated in Sicily with reference to beta-lactamase production.

The in vitro activity of cefdinir (CI-983, FK-482), an orally absorbed aminothiazolyl cephalosporin, was evaluated against all 287 strains of Haemophilus influenzae, Haemophilus parainfluenzae, Moraxella catarrhalis, Streptococcus pneumoniae and Streptococcus pyogenes in comparison with cefaclor, cefuroxime, amoxicillin, amoxicillin-clavulanic acid, erythromycin and cotrimoxazole. The bactericidal activity of cefdinir, cotrimoxazole, amoxicillin-clavulanic acid and erythromycin was determined against H. influenzae, M. catarrhalis and S. pneumoniae. With the exception of one beta-lactamase negative ampicillin-resistant strain of H. influenzae (resistant to all antibiotics tested), no resistance to cefdinir was observed (MIC < or = 1 mg/l). Cefdinir was active against H. influenzae, H. parainfluenzae and M. catarrhalis regardless of whether or not they produced beta-lactamase. In general, the inhibitory concentrations of cefdinir against H. influenzae, H. parainfluenzae and M. catarrhalis were similar to those of amoxicillin/clavulanic acid, one or two dilutions lower than those of cefuroxime and four dilutions lower than those of cefaclor and cotrimoxazole. Against S. pneumoniae and S. pyogenes cefdinir had the same activity as cefuroxime and amoxicillin but was more effective than the other antibiotics tested. Kinetic studies showed that cefdinir was rapidly bactericidal at concentrations 2 and 4 times the minimum inhibitory concentration (MIC): a reduction of 99.9% in CFU values was generally observed after 6-8 h.

Administration, Oral↗
PubMed1996

Distribution of cefdinir, a third generation cephalosporin antibiotic, in serum and pulmonary compartments.

The distribution of a new cephalosporin, cefdinir, in serum, epithelial lining fluid (ELF), bronchial mucosa and alveolar macrophages was studied in 17 adults following a single oral dose of 300 or 600 mg of cefdinir; tissue samples being obtained by diagnostic bronchoscopy approximately 4 h after this dose. Mucosal biopsies were taken, alveolar macrophages harvested by lavage, and ELF volume derived from urea concentrations in bronchial lavage fluid and blood. A microbiological assay for cefdinir was performed in serum, bronchial mucosa, ELF and alveolar macrophages. In patients taking 300 mg of cefdinir, the median concentrations of cefdinir were 2.00 mg/L (range 1.40-8.00) in serum, 0.78 mg/L (range 0-1.33) in bronchial mucosa, and 0.29 mg/L (range 0-4.73) in ELF. In patients taking 600 mg, the median concentrations were 4.20 mg/L (range 3.05-6.40) in serum, 1.14 mg/L (range 0-1.92) in bronchial mucosa, and 0.49 mg/L (range 0-0.59) in ELF. Cefdinir did not penetrate macrophages.

Administration, Oral↗
PubMed1993

Intestinal brush-border transport of the oral cephalosporin antibiotic, cefdinir, mediated by dipeptide and monocarboxylic acid transport systems in rabbits.

Intestinal absorption of the orally active cephalosporin, cefdinir, was investigated using brush-border membrane vesicles prepared from rabbit small intestine. The initial uptake of cefdinir was pH-dependent, with increased uptake at acidic pH, and was not influenced by either sodium gradient or membrane potential difference. Cefdinir uptake was saturable with an apparent Michaelis constant of 8.1 mM. Initial uptake of cefdinir was inhibited by dipeptides (glycyl-L-proline and glycylsarcosine), beta-lactam antibiotics (cephradine, cefixime and penicillin V), and monocarboxylic acids (acetic acid and L-lactic acid), whereas the uptake of cephradine and cefixime was not inhibited by monocarboxylic acids. Cefdinir significantly inhibited the initial uptake of cephradine, cefixime and [3H]acetic acid. From these results, it was suggested that cefdinir was transported across brush-border membranes by both dipeptide and monocarboxylic acid carriers.

Acetates↗
PubMed1995

Suction-induced blister fluid penetration of cefdinir in healthy volunteers following ascending oral doses.

The pharmacokinetics and suction-induced blister fluid penetration of cefdinir following single oral administrations of 200, 300, 400, and 600 mg were studied in 16 healthy young male volunteers according to a Latin square design. Plasma, blister, and urine samples were assayed by high-pressure liquid chromatography. We observed a nonlinear relationship (P = 0.02) between the dose and the maximum concentration in plasma as well as between the dose and the area under the concentration-time curve (AUC) in plasma (P < 0.001), which may be indicative of a limited absorption process. This resulted in a lower AUC value than expected as well as a smaller fraction of cefdinir excreted unchanged at a dose of 600 mg. Renal clearance decreased with increasing doses (P < 0.006; analysis of variance with the Latin square design and Games-Howell procedure). Maximal cefdinir concentrations in blister fluid were delayed compared with concentrations in plasma. Blister fluid penetration measured by the ratio of the AUC in blister fluid to the AUC in plasma was extensive (92.4 to 108.4%). Cefdinir concentrations in blister fluid remained equal to or higher than the concentrations in plasma from 6 to 12 h following cefdinir administration. On the basis of the concentrations in blister fluid and the in vitro MIC data, we estimated that cefdinir at 200 to 400 mg administered twice daily would be adequate to treat uncomplicated skin infections caused by Streptococcus pyogenes. Seven volunteers experienced episodes of light-to-moderate diarrhea. These adverse events occurred irrespective of dose.

Adult↗
PubMedDate not supplied

Morphological alterations of Staphylococcus aureus and Streptococcus pyogenes exposed to cefdinir, a new oral broad-spectrum cephalosporin.

Affinity for penicillin-binding proteins (PBPs) and the morphological alteration of Staphylococcus aureus 209-P JC and Streptococcus pyogenes C-203 exposed to cefdinir were studied. Although cefdinir was bactericidal against both strains, the extent of the decrease in colony-forming units (CFU) was similar in a fairly wide range of concentrations. Transmission electron microscopy of S. aureus 209-P JC revealed that cefdinir induced thickening of the cross wall and frequent cell lysis at low concentrations. The lytic sites were seen at the site of septum formation. In S. pyogenes C-203, cefdinir induced thickening of the peripheral wall and cross wall, and protoplast-like cells were observed during the incubation period. Cefdinir showed high affinity for all PBPs of S. aureus 209-P JC and S. pyogenes C-203. The drastic changes in the morphology of S. aureus and S. pyogenes were caused by binding of cefdinir to all PBPs.

Bacterial Proteins↗
PubMed1993

Cefdinir: in vitro activity study and effect of human serum.

The in-vitro activity of cefdinir (Cl-983, FK482), an orally absorbed aminothiazole cephalosporin, was compared with that of penicillin, ampicillin, amoxycillin, amoxycillin/clavulanic acid (2/1), cefaclor, cefuroxime, cefixime, cefotaxime, vancomycin and erythromycin against 370 clinical isolates of Gram-negative and Gram-positive bacteria. Cefdinir was highly active against Staphylococcus aureus and S. epidermidis, inhibiting 90% of the strains at doses of 0.25 and 0.5 mg/l respectively. However, cefdinir was not active against methicillin-resistant S. aureus (range 16- > 128 mg/l). The respiratory pathogens Moraxella catarrhalis, Streptococcus pneumoniae, and S. pyogenes were also susceptible (MIC90 < or = 0.5 mg/l), but against Enterococcus spp. cefdinir displayed no useful activity. The common members of the family Enterobacteriaceae were susceptible (MIC90 < or = 1 mg/l), but those possessing chromosomal beta-lactamases were more resistant (MIC90 2-8 mg/l). The presence of human serum had little effect on MICs of cefdinir. These results indicate that cefdinir exhibited a wide spectrum for an oral cephalosporin and support its possible clinical use against susceptible pathogens in infections of the skin, soft tissue, respiratory and urinary tracts.

Anti-Bacterial Agents↗
PubMed1993

Cefdinir-induced modification of the susceptibility of bacteria to the antibacterial activity of human serum and polymorphonuclear neutrophils.

The effect of serum on the bactericidal activity of cefdinir, and the ability of the antibiotic to modify the interaction of bacteria with human polymorphonuclear neutrophils were assessed. In the presence of antibiotic, serum-resistant Escherichia coli were sensitised to the bactericidal activity of normal human serum. Cefdinir enhanced opsonophagocytic killing of Escherichia coli and Staphylococcus aureus at suprainhibitory concentrations. Significant potentiation of killing occurred with the combination of inhibitory concentrations of cefdinir, neutrophils and sub-optimal levels of serum opsonins. Pre-exposure of Escherichia coli, but not Staphylococcus aureus, to cefdinir enhanced phagocytic uptake and killing of the antibiotic-damaged bacteria. These results indicate that cefdinir-mediated phenotypic modification of Escherichia coli renders the bacteria susceptible to serum antibacterial activity and phagocytic uptake and intracellular killing.

Bacteria↗
PubMed1996

Degradation kinetics and isomerization of cefdinir, a new oral cephalosporin, in aqueous solution. 2. Hydrolytic degradation pathway and mechanism for beta-lactam ring opened lactones.

Hydrolysis of cefdinir leads to pH-dependent isomerizations and beta-lactam ring-opening. Lactam ring opened gamma-lactones were produced as a mixture of four diastereoisomers based on the lactone methyl, and C-6 isomerizations in acidic to neutral solutions. Cefdinir and its 7-epimer were hydrolyzed to clarify the pathway leading to these lactones and the mechanism of C-6 epimerization with the aid of chiral separation techniques. Chiral separation using a bovine serum albumin column was employed to detect the beta-lactam ring opened products of cefdinir and its 7-epimer; the C-6 and C-7 isomerization was thereby observed; however, it was found to be pH-dependent at pH > or = 9. Optical activity detection applied to the lactones produced from cefdinir and its 7-epimer demonstrated that the corresponding peaks of these lactones were enantiomeric pairs. In addition, the smallest rate constant at pH 4 was observed for C-6 epimerization of the lactones, and it was found to proceed without deprotonation at C-6 by 1H-NMR spectroscopy. From the results of these studies, a plausible mechanism for C-6 epimerization has been proposed. Additionally, it was confirmed that two degradation pathways were involved during hydrolysis of cefdinir to the lactone.

Administration, Oral↗
PubMed1993

Stability of cefdinir (C1-983, FK482) to extended-spectrum plasmid-mediated beta-lactamases.

Fourteen plasmid-encoded extended-spectrum beta-lactamases were purified from Escherichia coli transconjugants of original clinical isolates. The Vmax, Km and Vmax/Km were each determined for ampicillin, carbenicillin, cephaloridine, cephalexin, cefuroxime, cefixime, cefdinir, ceftazidime and cefotaxime as substrates with eight of these enzymes and with the narrow-spectrum beta-lactamase, TEM-1. The relative rates of hydrolysis of ampicillin, cephaloridine, cephalexin, cefuroxime, cefixime, cefdinir, ceftazidime and cefotaxime were also determined for the remaining six enzymes. Cefdinir had Vmax/Km or relative rates of hydrolysis values either equal to or lower than ampicillin, cephaloridine, cephalexin and cefotaxime for all the enzymes tested. Overall, cefdinir was more stable to the 15 beta-lactamases tested than either cefuroxime or cefixime; however, ceftazidime was more stable than cefdinir to hydrolysis by eight of the enzymes tested.

Cefdinir↗