Deciphering mobile genetic elements disseminating macrolide resistance in <i>Streptococcus pyogenes</i> over a 21 year period in Barcelona, Spain

Abstract Objectives To phenotypically and genetically characterize the antibiotic resistance determinants associated mobile genetic elements (MGEs) among macrolide-resistant (MR) Streptococcus pyogenes [Group A streptococci (GAS)] clinical isolates collected in Barcelona, Spain. Methods Antibiotic susceptibility testing was performed by microdilution. Isolates were emm MLST typed 55 whole-genome sequenced to determine nature of macrolide their larger MGE chromosomal context. Results Between 1998 2018, 142 1028 GAS (13.8%) MR. Among 108 available for molecular characterization, 41.7% had cMLSB, 30.5% iMLSB 27.8% M phenotype. Eight erm(B)-containing strains notable having an MDR phenotype conferred encoding several genes. MR comprised distinct lineages as defined combination ST. Although most only transiently present, emm11/ST403 clone persisted throughout period. Two lineages, emm9/ST75 with erm(B) emm77/ST63 erm(TR), emerged 2016–18. The predominantly encoded on Tn916 family transposons (21/31) different contexts, other MGEs (Tn6263, ICESpHKU372 one harbouring cluster called ICESp1070HUB). erm(TR) found ICESp2905 (8/17), ICESp1108-like (4/17), ICESpHKU165 (3/17) two structures described this study (IMESp316HUB ICESp3729HUB). [mef(A)-msr(D)] linked phage φ1207.3. integrative conjugative element/integrative mobilizable element (ICE/IME) groups classified basis gene content within conjugation modules. These MGEs, which corresponded MR-containing or site integration. Conclusions We detected erm(TR). This is first known description Tn6263 three [IMESp316HUB, ICESp3729HUB ICESp1070HUB] Periods high rates our area mainly expansion certain predominant while low periods sporadic prevalence more frequent.