T serotypes and antimicrobial susceptibilities of group A streptococcus isolates from pediatric pharyngotonsillitis.

Group A streptococcus (GAS) is a major cause of pediatric pharyngotonsillitis. In this study we determined the T serotype and antimicrobial susceptibility of GAS isolates from Japanese children. From January to December 2006, a total of 438 isolates of GAS were obtained from pharyngeal swabs of 438 children with pharyngotonsillitis. The commonest T serotype was type 1 (110 strains, 25.1%), followed by type 12 (107, 24.4%) and type 4 (77, 17.6%). All GAS isolated from pharyngeal swabs were susceptible to beta-lactams (benzylpenicillin, amoxicillin, cefotaxime, ceftriaxone, imipenem, panipenem, and cefditoren) and vancomycin, but 19.6, 19.6, 3.2, 11.6, and 27.6% were resistant to erythromycin, clarithromycin, clindamycin, minocycline, and norfloxacin, respectively. Resistance varied considerably with the T serotype. In particular, type 4 isolates had the highest resistance (67.5, 67.5, 26.0, and 53.2% were resistant to erythromycin, clarithromycin, minocycline, and norfloxacin, respectively).

Five-day oral cefditoren pivoxil versus 10-day oral amoxicillin for pediatric group A streptococcal pharyngotonsillitis.

We prospectively compared the efficacy of oral cefditoren-pivoxil and conventional oral amoxicillin for pharyngotonsillitis caused by group A streptococcus in children. Either oral cefditoren-pivoxil (3 mg/kg t.i.d. for 5 days) or amoxicillin (10 mg/kg t.i.d. for 10 days) was administered to patients with group A streptococcal pharyngotonsillitis attending the pediatric outpatient clinic of Showa Hospital (Konan, Japan) between January and December 2006. Diagnosis was based on isolation of bacteria from a pharyngeal swab. Culture was always done to confirm eradication, and urinalysis and follow-up were performed at least once weekly for 4 weeks. Among 258 patients, 103 (aged 5.5 +/- 2.3 years) received cefditoren-pivoxil and 155 (aged 5.2 +/- 2.0 years) received amoxicillin. There were no significant between-group differences in age, sex, or symptoms. Eradication was confirmed in 99% (102/103) of the cefditoren-pivoxil group and 100% of the amoxicillin group. Recurrence within 4 weeks occurred in 8 and 15 patients in the cefditoren-pivoxil and amoxicillin groups, respectively, showing no significant difference in the recurrence rate, and all isolates had the same serotypes as before. There were no clinically significant adverse reactions or complications. The 50%/90% minimum inhibitory concentrations (microg/ml) of cefditoren-pivoxil and amoxicillin for the 258 isolates were < or =0.03/< or =0.03 and < or =0.03/0.06, respectively, so all isolates were susceptible to both agents. Because the efficacy for pediatric group A streptococcus pharyngotonsillitis was similar between oral cefditoren-pivoxil for 5 days and amoxicillin for 10 days, the shorter treatment period may make the former regimen preferable.

DNA sequence analysis of varicella-zoster virus gene 62 from subclinical infections in healthy children immunized with the Oka varicella vaccine.

A live attenuated varicella vaccine, the Oka vaccine strain (vOka), is routinely administered to children in Japan and other countries, including the United States. vOka consists of a mixture of genotypically distinct variants, but little is known about the growth potential of each variants in vivo. We isolated varicella-zoster virus (VZV) DNA sequences from the peripheral blood mononuclear cells (PBMCs) of asymptomatic healthy children immunized with the Oka varicella vaccine. VZV gene 62 DNA fragments were detected in 5 of 166 (3.0%) PBMC samples by nested PCR within 5 weeks of the vaccination. Sequence analysis of VZV DNA from these five PBMC samples indicated that multiple viral clones in the vaccine could infect vaccinees and replicate in vivo. We also provide evidence that a nonsynonymous substitution at position 105356 may affect viral replication in vivo.