2 a 10-day course of oral cephalosporin for recurrent GABHS pharyngitis in children. 2. Materials and Methods 2.1. Subjects. In a prospective, multicenter surveillance study, a total of 299 children with a history of at least 1 episode of GABHS pharyngitis were enrolled at private oﬃces of 41 practicing pediatricians and hospitals of 23 practicing pediatricians between May 2006 and August 2007 in Hokkaido, the northernmost island of Japan. A total of 73 children were excluded after enrollment because of incomplete follow-up (n = 61), inappropriate enrollment (n = 11), and noncompliance (n = 1). The number of eligible patients for the study was 226. The 226 children (138 males and 88 females; 2 to 14 years old; mean age: 6.8 years; SD: 2.0 years) were diagnosed as having GABHS pharingitis by both clinical ﬁndings and a positive reaction in pharyngeal swab specimens using commercially available rapid antigen detection tests (RADTs) for GABHS (Immunocard ST Strep A, TFB, INC., Tokyo; Dipstick Eiken Strept A, Eiken Chemical Co., Ltd., Tokyo; Quickview Strep A, Wako Pure Chemical Industries, Ltd., Osaka). The clinical ﬁndings included presence of oropharyngeal erythema or tonsillar exudate, fever, cervical lymphadenitis, and sore throat. Patients with signs and symptoms suggestive of viral infection (rhinorrhea, cough, conjunctivitis) were excluded. Follow-up visit and follow-up culture were scheduled 3 weeks after the initiation of therapy. The culture samples were obtained by rubbing over the posterior portion of the pharynx and both tonsils with a sterile, rayon-tipped swab. All pharyngeal swab specimens were collected after obtaining informed consent from the patients or children’s parents. The swabs were placed in an aerobic transport system and then transported to our laboratory. The children with subsequent GABHS pharyngitis within the follow-up period were also diagnosed by both clinical ﬁndings and results of RADTs. The 226 patients were treated with cefditoren pivoxil (9 mg/kg; maximum dose of 300 mg/day, 3 times a day) for 5 days (77 patients) or for 10 days (149 patients). Since each pediatrician arbitrarily decided the period of antibiotic treatment, there was no complete randomization of the patients. 2.2. Deﬁnition. Clinical response to treatment was deﬁned here as recurrence (clinical treatment failure; clinically and RADT-conﬁrmed GABHS pharyngitis within the follow- up period, irrespective of T serotype) and as clinical cure (clinical treatment success; no clinical ﬁndings of GABHS pharyngitis within the follow-up period). Bacteriologic response to treatment was deﬁned here as eradication (bac- teriologic treatment success; no GABHS isolation at follow- up visit) and as noneradication (bacteriologic treatment failure; GABHS isolation without overt pharyngitis at follow- up visit, irrespective of T serotype). Treatment success was, therefore, deﬁned as bacteriologic treatment success with no recurrence, and treatment failure was deﬁned as either clinical or bacteriologic treatment failure. International Journal of Pediatrics 2.3. Serotyping. Serotyping was examined for T types by the agglutination method using Group A streptococcus hemolyticus T typing immunoserum “SEIKEN” (Denka Seiken Co., Ltd., Tokyo). 2.4. Statistical Analysis. Quantitative variables were com- pared using Welch’s t-test, and qualitative variables were compared using the chi-square test with Fisher’s exact test. For all statistical comparisons, P < .05 was considered to be signiﬁcant. 3. Results and Discussion 3.1. Results. The characteristics of children with repeated GABHA pharyngitis are shown in Table 1. The mean number of episodes of repeated GABHS pharyngitis including the present episode was 2.79 (range: 2–12; SD: 1.35). Of the 226 patients, 182 (80.5%) patients had a history of at least 2 episodes of repeated GABHS pharyngitis. The mean interval between preceding and present episodes was 10.48 months (range: 0.4–79 months; SD: 13.85). Of the 226 patients, 98 (43.3%) patients had preceding GABHS pharyngitis within 3 months before the present GABHS pharyngitis. The mean length of follow-up excluding recurrence cases (deﬁnition of recurrence case given below) was 22.20 days (range: 14– 35 days; SD: 2.98 days). Of the 226 patients, 218 (96.4%) patients were followed up for 14–28 days after the initiation of therapy. The characteristics of children treated for 5 days and 10 days are shown in Table 1. The ratios of males to females were 1 : 0.67 in the 5-day treatment group and 1 : 0.62 in the 10-day treatment group. Mean ages were 6.70 years (range: 3–12 years; SD: 1.93 years) in the 5-day treatment group and 6.80 years (range: 2–14 years; SD: 2.10 years) in the 10-day treatment group. Mean numbers of episodes of repeated GABHS pharyngitis were 2.75 (range: 2–12; SD: 1.54) in the 5-day treatment group and 2.81 (range: 2–8; SD: 1.24) in the 10-day treatment group. Mean intervals between preceding and present episodes were 12.95 months (range: 0.5–79 months; SD: 17.30 months) in the 5-day treatment group and 9.20 months (range: 0.4–55 months; SD: 11.47 months) in the 10-day treatment group. Mean lengths of follow-up excluding recurrence cases were 22.57 days (range: 14–32 days; SD: 3.03 days) in the 5- day treatment group and 22.02 days (range: 15–35 days; SD: 2.94 days) in the 10-day treatment group. There were no signiﬁcant diﬀerences between the two treatment groups in the distribution of age, gender, number of episodes of repeated GABHS pharyngitis, interval between preceding and present episodes, and length of follow-up. The clinical and bacteriological results are shown in Table 2. Recurrence (clinical treatment failure) occurred in 7 (9.1%) of the 77 children in the 5-day treatment group and in 1 (0.7%) of the 149 children in the 10-day treatment group. The 5-day treatment group showed a signiﬁcantly higher incidence of recurrent GABHS pharyngitis than that in the 10-day treatment group (P = .003). The eight patients with recurrent GABHS phayryngitis included 5 males and 3 females with a mean age of 6.36 years (range: