is a previously neglected, newly emerging multidrug-resistant zoonotic pathogen. newly emerging

is a previously neglected, newly emerging multidrug-resistant zoonotic pathogen. newly emerging multidrug-resistant zoonotic pathogen that causes meningitis, septicemia, and arthritis in humans, and is one of the major pathogens that led to substantial economic losses in the intensive swine industry (Lun et al., 2007; Gottschalk et al., 2010). Outbreaks of human infections in China, of which strains were resistant to tetrecyclines and aminoglycosides, in 2005 posed a large public health challenge (Tang et al., 2006; Yu et al., 2006). Previous studies have suggested that is an important antimicrobial resistance (AMR) reservoir that can contribute to the spread of resistance genes to the above-mentioned streptococci (Palmieri et al., 2011; Huang et al., 2016). Increasing resistance of streptococci to commonly used antimicrobials including tetracyclines (up to >90%) and macrolides (up to >70%) have been reported worldwide since the 1980s (Aarestrup et al., 1998; Zhang et al., 2008; Palmieri et al., 2011), and a number of AMR genes have been identified ( (Roberts, 2005; Palmieri et al., 2011). Previous studies reported that this dissemination of these AMR genes in streptococci are associated with different mobile genetic elements (MGEs) (Roberts and Mullany, 2009; Varaldo et al., 2009). MGEs are ubiquitous among all prokaryotes and play a significant role in horizontal gene transfer (HGT) resulting in intra- and interspecies dissemination of AMR and virulence determinants (Dobrindt et al., 2004; Frost et al., 2005; Juhas et al., 2009; Bellanger et al., 2014). The pool of all genes within MGEs, such as integrative and conjugative elements (ICEs), plasmids, insertion sequences (Is usually), transposons, prophages, integrons and other genomic islands, are collectively referred to as mobilome (Frost et al., 2005). Several MGEs, carrying AMR determinants for tetracyclines, macrolides, aminoglycosides, and chloramphenicol, have been identified in (Chen et al., 2007; Holden et al., 2009; Li et al., 2011; Palmieri et al., 2011). A strains, was responsible for full bacterial virulence in two major outbreaks in China (Tang et al., 2006; Chen et al., 2007; Li et al., 2008). The 89 K shares similarity with conjugation modules of Tn5253, but its integrase belongs to the ICEsite instead at site of Tn5253 (Ayoubi et al., 1991; Li et al., 2011). A strain isolated from a patient with meningitis and is highly comparable with the main m46.1 and Sa04 (Brenciani et al., 2010; Palmieri et al., 2010). More recently, chimeric and tandem of ICEs in streptococci have been reported (Yao et al., 2015; Huang et al., 2016), which indicate conversation of MGEs occurs to extend MGE diversity and complexity. Although, some MGEs have been Cyanidin chloride supplier identified in to have a better understanding of resistome. Comparative and evolution analysis were conducted at and loci Rabbit Polyclonal to Adrenergic Receptor alpha-2B in as well as (in total 6491 genome sequences obtained from GenBank) to explore the diversity and evolution of MGEs. This is Cyanidin chloride supplier the first study that provides the landscape of the prevalence and diversity of MGEs at and loci in to comprehend the underlying evolutionary mechanism of MGEs. Our work Cyanidin chloride supplier Cyanidin chloride supplier further confirms the hypothesis that is an important AMR reservoir and suggest that might Cyanidin chloride supplier be a MGEs reservoir for other streptococci which promoted the worldwide emergence of antibiotic-resistant streptococcal contamination. Materials and methods Bacterial strains and antimicrobial susceptibility assessments A total of seven isolates from our routine surveillance on antimicrobial resistance were chosen and sequenced in this study as they displayed different resistance genotype (Table S1). The complete genomes of five strains from GenBank database were also analyzed (Table S1). Isolated colonies were produced on Todd-Hewitt broth (Difco Laboratories) supplemented with 5% (v/v) sheep blood and incubated at 37C. experiments were performed in a Biosafety level 2 laboratory. Erythromycin, tetracycline, streptomycin, and kanamycin were purchased from Sigma-Aldrich Co. LLC., Shanghai, China. Antimicrobial susceptibility assessments (MICs) were determined by a standard broth micro dilution method. Whole-genome sequencing and amplification experiments The whole genomes of seven strains were sequenced and assembled.