Recent independent emergence of multiple multidrug-resistantSerratia marcescensclones within the United Kingdom and Ireland

Abstract

Serratia marcescens, a member of the Enterobacteriaceae family, is a Gram-negative bacterium responsible for a wide range of nosocomial infections. The emergence of multidrug-resistant strains is an increasing danger to public health. To design effective means to control the dissemination of S. marcescens, an in-depth analysis of the population structure and variation is required. Utilizing whole-genome sequencing, we characterized the population structure and variation, as well as the antimicrobial resistance determinants, of a systematic collection of antimicrobial-resistant S. marcescens associated with bloodstream infections in hospitals across the United Kingdom and Ireland between 2001 and 2011. Our results show that S. marcescens is a diverse species with a high level of genomic variation. However, the collection was largely composed of a limited number of clones that emerged from this diverse background within the past few decades. We identified potential recent transmissions of these clones, within and between hospitals, and showed that they have acquired antimicrobial resistance determinants for different beta-lactams, ciprofloxacin, and tetracyclines on multiple occasions. The expansion of these multidrug-resistant clones suggests that the treatment of S. marcescens infections will become increasingly difficult in the future.

Genomic epidemiology of multidrug‐resistant Gram‐negative organisms

“…While sequencing isolate collections from single institutions provides insights into what is happening within the confines of a facility, understanding the ultimate origin of MDROs circulating within hospitals will require sequencing and analysis of regional isolate collections. Moradigaravand and colleagues recently took such a regional approach to understand the population structure of three MDR members of the Enterobacteriaceae family: E. cloacae , Serratia marcescens , and K. pneumoniae . In contrast to MDR K. pneumoniae , in which epidemic clones dominate specific regions, E. cloacae and S. marcescens both exhibited a polyclonal structure across 37 hospitals in the UK and Ireland, indicating the convergent emergence and spread of multiple MDR lineages.…”

“…Moradigaravand and colleagues recently took such a regional approach to understand the population structure of three MDR members of the Enterobacteriaceae family: E. cloacae, Serratia marcescens, and K. pneumoniae. 56,61,62 In contrast to MDR K. pneumoniae, in which epidemic clones dominate specific regions, E. cloacae and S. marcescens both exhibited a polyclonal structure across 37 hospitals in the UK and Ireland, indicating the convergent emergence and spread of multiple MDR lineages. This finding contrasts to a recent report by Hargreaves and colleagues, who observed the emergence and spread of a lineage of bla-KPC-carrying E. cloacae across multiple hospitals in North Dakota and Minnesota.…”

Piperacillin-Tazobactam versus Other Antibacterial Agents for Treatment of Bloodstream Infections Due to AmpC β-Lactamase-Producing Enterobacteriaceae

“…The widespread presence of ampC in Serratia spp. isolates that were linked with preserved susceptibility to cephalosporins was recently described in a large genomic survey from the United Kingdom (20). Additional mutations, for example in the ampC regulators AmpD and AmpR (6), may be needed to manifest the AmpC phenotype in Serratia spp.…”

Draft Genome Sequences of Pandrug-Resistant Serratia marcescens Clinical Isolates Harboring bla NDM-1

“…However, now it is increasingly being recognized as an emerging pathogen, causing severe infections and outbreaks particularly affecting preterms and neonates (1–3). …”

“…S. marcescens displays intrinsic resistance to ampicillin and colistin, however, clinical isolates of S. marcescens with pandrug resistance are rare (3, 4). The pandrug-resistant S. marcescens isolates SM1978 and SM1890 harboring bla NDM-1 obtained from a leukemia patient and a patient with a urinary tract infection, respectively, were previously described (5).…”