Abstract
From April 2013 to March 2014, we examined 215 group A streptococcal isolates from 215 patients with respiratory tract infections (age, 6 months to 14 years; median, 5 years and 2 months) confined in our Pediatrics Department. For all the isolates, we determined the T serotypes and MICs of 15 antimicrobial agents [benzylpenicillin (PCG), amoxicillin (AMPC), cefotaxime (CTX), ceftriaxone (CTRX), cefditoren (CDTR), cefcapene (CFPN), panipenem (PAPM), imipenem (IPM), erythromycin (EM), clarithromycin (CAM), clindamycin (CLDM), minocycline (MINO), tosufloxacin (TFLX), levofloxacin (LVFX), and vancomycin (VCM)]. We compared the results with those of our four previous studies (1996, n = 431; 2001, n = 317; 2003, n = 295; 2006, n = 438). In 2013, the most prevalent serotypes were T12 (34%), B3264 (30%), T1 (11%), and T28 (9%), in descending order. Although isolation rates varied, T12 was the most frequent in all previous studies (1996, 22%; 2001, 37%; 2003, 38%; 2006, 24%). Among all the isolates tested, 58%, 58%, 49%, 5%, 8%, and 2% showed resistance to EM, CAM, CLDM, MINO, TFLX, and LVFX, respectively. All the CLDM-resistant isolates were also resistant to EM and CAM. Among the 1,696 isolates in all 5 studies, no strain showed resistance to β-lactams or VCM. The EM and CAM resistance rates increased over time, being respectively 9% and untested in 1996, 14% and 13% in 2001, 20% and 20% in 2003, and 20% and 20% in 2006. In 2013, both rates increased to 58%. T12 serotype isolates showed marked increases in EM and CAM resistance rates from 20% in 2006 to 85% in 2013.
