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[Laboratory and clinical studies on SY5555 in pediatrics]
1Department of Pediatrics, Meitetsu Hospital.
Insights
SY5555, an oral penem antibiotic, demonstrates potent antibacterial activity against Streptococcus pneumoniae, including resistant strains. Clinical studies show favorable pharmacokinetics in pediatric patients, supporting its potential use.
Area of Science:
- Pharmacology
- Microbiology
- Pediatrics
Background:
- SY5555 is the first oral penem antibiotic developed in Japan for pediatric use.
- This study evaluates its antibacterial efficacy and pharmacokinetic profile in children.
Observation:
- SY5555 exhibited potent in vitro activity against 42 clinical isolates of Streptococcus pneumoniae, with MIC values below 0.39 µg/mL.
- It demonstrated excellent activity against benzylpenicillin (PCG)-resistant strains, comparable to other beta-lactam antibiotics like cefotaxime (CTX) and imipenem (IPM).
- Pharmacokinetic studies in pediatric patients showed dose-dependent plasma concentrations and elimination half-lives, influenced by feeding status.
Findings:
- SY5555 displayed strong antibacterial effects against both sensitive and resistant Streptococcus pneumoniae strains.
- Peak plasma levels were achieved within 1 hour post-administration, with varying half-lives and urinary recovery rates.
- Fecal excretion data was also collected, providing a comprehensive pharmacokinetic profile.
Implications:
- SY5555 shows promise as an effective oral antibiotic for pediatric infections caused by Streptococcus pneumoniae.
- Its pharmacokinetic properties suggest suitability for pediatric dosing regimens.
- Further clinical evaluation is warranted to establish its therapeutic role in pediatric infectious diseases.
Abstract:
Laboratory and clinical studies were performed on SY5555, the first penem oral antibiotic developed in Japan, in the pediatric field. The following results were obtained. 1. Antibacterial activities of the drug against 42 strains of Streptococcus pneumoniae clinically isolated in 1993 were compared to those of 13 other drugs mainly composed of beta-lactam preparations. Minimum inhibitory concentration (MIC) values of SY5555 were below 0.39 micrograms/ml for all strains examined, thus the drug showed an excellent activities against benzylpenicillin (PCG)-resistant strains as well. When the antibacterial effects of individual drugs were compared using MIC50 and MIC90 as indices, SY5555 was the most effective against PCG-sensitive strains and similar to cefazolin (CEZ), cefotaxime (CTX), cefuzonam (CZON), amoxicillin (AMPC) and imipenem (IPM). It also showed excellent antibacterial effects against moderately PCG-resistant strains, and the activities were similar to IPM. Activities of SY5555 on highly PCG-resistant strains were similar to those of CTX, CZON and IPM. 2. SY5555 at a dose of 5 mg/kg or 10 mg/kg was administered to 16 pediatric patients in the fasting state or after meal to examine its plasma concentration and urinary excretion rate. The fecal excretion was measured in 5 affected children treated with this drug. When the drug at a dose of 5 mg/kg was administered to 11 older children, 5 with ages 5-12 years and 6 with ages 10-13 years in the fasting state and after meal, respectively. Peak plasma levels were reached at 1 hour after administration in the two groups, and they were 0.93 +/- 0.25 and 2.44 +/- 1.25 micrograms/ml, respectively. The plasma levels then decreased gradually with half-lives of 1.95 +/- 1.09 and 0.72 +/- 0.21 hours, respectively. Urinary recovery rates in the first 6 hours after administration were 1.98 +/- 0.82 and 4.13 +/- 1.40%, respectively. In 3 cases (6-9 years) treated with the drug at a dose of 10 mg/kg after meal, a peak of 1.58 +/- 0.81 micrograms/ml appeared 1 hour after administration with a half-life of 1.08 +/- 0.30 hours and with the urinary recovery rate in the first 6 hours after administration of 3.46 +/- 1.03%. When the drug at a dose of 10 mg/kg was administered to 2 infants (2-3 months post partum) after meal, a peak plasma level of 3.74 micrograms/ml appeared 1 hour after administration with a half-life of 1.19 hours.(ABSTRACT TRUNCATED AT 250 WORDS)