Molecular Mechanisms of Tetracycline and Macrolide Resistance andemmCharacterization ofStreptococcus pyogenesIsolates in Tunisia

Abstract

Streptococcus pyogenes or group A Streptococcus, a major human pathogen, remains susceptible to beta-lactams, but resistance to other antibiotics is becoming more common. The purpose of this study was to characterize both phenotypic and genotypic epidemiological markers of group A Streptococcus and to identify the mechanisms of resistance to macrolides and tetracyclines. A total of 103 strains, isolated at Charles Nicolle University Hospital of Tunis, were investigated. The rate of resistance to erythromycin was low (5%), whereas a high rate of tetracycline resistance was found (70%). All the macrolide-resistant isolates expressed the constitutive macrolide, lincosamide, and streptograminB phenotype and harbored the erm(B) gene. Resistance to tetracycline was mainly due to the tet(M) gene, which is commonly associated with the conjugative transposon Tn916. No significant association was found between erm(B) and tet(M) genes. The tetracycline-resistant strains belonged to 28 distinct emm types. Among them, emm118 was the most prevalent type, followed by emm42, std432, emm76, and emm18. However, emm1, emm4, emm6, emm28, and emm3 were the most frequent types among tetracycline susceptible isolates. Only emm118 and emm42 types (p ≤ 0.05) were significantly associated with resistance to tetracycline.

Prevalence of group A β-haemolytic Streptococcus among children with pharyngitis in Jimma town, Southwest Ethiopia

“…27 However, various levels of resistance to erythromycin and clindamycin were reported in Turkey, 16 Tunisia 28 and China. 29 In the present study, 52.5% GAS isolates were resistant to tetracycline which was comparable with 68% reported in Ethiopia 6 and 50% in Brazil, 27 but much lower than 70% and 94% resistance rates documented in Tunisia 28 and China 29 respectively.…”

Molecular epidemiology and mechanisms of antibiotic resistance inEnterococcusspp.,Staphylococcusspp., andStreptococcusspp. in Africa: a systematic review from a One Health perspective

“…MDR VREs increase VRE‐associated mortality rates above figures caused by sensitive enterococci strains . As well, the evolution of macrolide resistance in drug‐resistant streptococci is limiting treatment options and resulting in high mortalities . These data support the need to prioritize antibiotic stewardship and increase One Health molecular studies across Africa to quickly identify and preempt full‐scale outbreaks and dissemination of pathogens.…”

“…Hraoui et al . reported a low macrolide resistance rate (5%, 5/103) and a high TET resistance rate (70%, 72/103) among human isolates, with tet (M), associated with Tn 916 , being responsible for TET resistance . Increased TET use in food animals was implicated in this instance, leading to the selection and dissemination of resistance genes from animals to humans.…”

Molecular characterization and evaluation of the emerging antibiotic-resistant Streptococcus pyogenes from eastern India

“…In the present study, high percentage of resistance was shown by tetracycline, which is in corroboration with the previous findings. 14 and 28 different tetracycline-resistant emm types were identified in studies from Spain and Tunisia, respectively [58, 59]. Present study identified 75 tetracycline-resistant isolates, belonging to 12 different emm genotypes.…”

“…Present study identified 75 tetracycline-resistant isolates, belonging to 12 different emm genotypes. These findings indicated that for study of different regions, S. pyogenes strains are approaching tetracycline-resistance, attributable to modifications in tet (M) gene commonly associated with the conjugative transposon Tn916 [59]. …”