Gajic, Ina (55428924700)Ina (55428924700)GajicMijac, Vera (6507998440)Vera (6507998440)MijacRanin, Lazar (6602522806)Lazar (6602522806)RaninGrego, Edita (6601987053)Edita (6601987053)GregoKekic, Dusan (36696225200)Dusan (36696225200)KekicJegorovic, Boris (55427940600)Boris (55427940600)JegorovicSmitran, Aleksandra (55865631000)Aleksandra (55865631000)SmitranPopovic, Suncica (57202639854)Suncica (57202639854)PopovicOpavski, Natasa (6507364674)Natasa (6507364674)Opavski2025-06-122025-06-122018https://doi.org/10.1089/mdr.2017.0306https://www.scopus.com/inward/record.uri?eid=2-s2.0-85056353456&doi=10.1089%2fmdr.2017.0306&partnerID=40&md5=69468556cd2131688de0c7427006f9e1https://remedy.med.bg.ac.rs/handle/123456789/6029In Serbia, the frequency of macrolide-resistant group A streptococci (MRGASs) increased significantly from 2006 to 2009. MRGAS analysis in 2008 revealed the presence of three major clonal lineages: emm75/mefA, emm12/mefA, and emm77/ermTR. The aim of the present study was to determine the prevalence of macrolide resistance and to evaluate variations in the clonal composition of MRGASs. The study included 1,040 pharyngeal group A streptococci collected throughout Serbia, which were tested for antimicrobial susceptibility. MRGAS isolates were further characterized by the presence of resistance determinants, emm typing, and pulsed-field gel electrophoresis analysis. The prevalence of macrolide resistance was 9.6%, showing a slight decrease compared with the rate of 12.5% (2008). Tetracycline resistance was present in 6% of isolates, while norfloxacin nonsusceptibility detected for the first time in Serbia was 9.8%. The M phenotype dominated (84%), followed by the constitutive macrolides, lincosamides, and streptogramin B phenotype (12%). Five emm types were detected: emm75, emm12, emm1, emm28, and emm89. The emm75/mefA (62%), emm12/mefA (14%), and emm12/ermB/tetM (6%) were predominant clones and were found in both the present and the previous study periods at different frequencies. The major change was the loss of emm77/ermTR/tetO, which contributed to 15% of MRGASs in 2008. © Copyright 2018, Mary Ann Liebert, Inc., publishers 2018.antibioticsbacteriaepidemiologygenotypingresistance