Global Spread of the hyl _Efm Colonization-Virulence Gene in Megaplasmids of the Enterococcus faecium CC17 Polyclonal Subcluster

Abstract

Enterococcus faecium has increasingly been reported as a nosocomial pathogen since the early 1990s, presumptively associated with the expansion of a human-associated Enterococcus faecium polyclonal subcluster known as clonal complex 17 (CC17) that has progressively acquired different antibiotic resistance (ampicillin and vancomycin) and virulence (esp Efm , hyl Efm , and fms) traits. We analyzed the presence and the location of a putative glycoside hydrolase hyl Efm gene among E. faecium strains obtained from hospitalized patients (255 patients; outbreak, bacteremic, and/or disseminated isolates from 23 countries and five continents; 1986 to 2009) and from nonclinical origins (isolates obtained from healthy humans [25 isolates], poultry [30], swine [90], and the environment [55]; 1999 to 2007). Clonal relatedness was established by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Plasmid analysis included determination of content and size (S1-PFGE), transferability (filter mating), screening of Rep initiator proteins (PCR), and location of vanA, vanB, ermB, and hyl Efm genes (S1/I-CeuI hybridization). Most E. faecium isolates contained large plasmids (>150 kb) and showed variable contents of van, hyl Efm , or esp Efm . The hyl Efm gene was associated with megaplasmids (170 to 375 kb) of worldwide spread (ST16, ST17, and ST18) or locally predominant (ST192, ST203, ST280, and ST412) ampicillin-resistant CC17 clones collected in the five continents since the early 1990s. All but one hyl Efm -positive isolate belonged to the CC17 polyclonal subcluster. The presence of hyl Efm megaplasmids among CC17 from Europe, Australia, Asia, and Africa since at least the mid-1990s was documented. This study further demonstrates the pandemic expansion of particular CC17 clones before acquisition of vancomycin resistance and putative virulence traits and describes the presence of megaplasmids in most of the contemporary E. faecium isolates with different origins.

Antimicrobial Resistance and Multilocus Sequence Typing of Vancomycin-ResistantEnterococcus faeciumIsolated from the Chungcheong Area

“…Hyl gene is translated into hyaluronidase protein acting as a pathogenic factor in Streptococcus pyogenens, Staphylococcus aureus, and Streptococcus pneumoniae [26], and commonly found in spreading disease causing organisms [11]. Especially in recent study in Spain E. faecium with hyl gene was reported to belong to CC17 polyclonal subcluster, which proved the relationship between CC17 and hyl gene [24]. In this study, it was found all 37 isolates had esp gene, and most of isolates (32 isolates, 86.5%) except 5 (CNS16, CBS3, CBS6, CBS9, EJS4) had hyl gene.…”

“…In addition, the fact that it can be transmitted with vanA resistance gene is believed to make contribution to wide spread of pathogenic VRE [23]. Currently there have been many reports about another pathogenic gene, hyl gene in addition to esp gene [24][25][26]. Hyl gene is translated into hyaluronidase protein acting as a pathogenic factor in Streptococcus pyogenens, Staphylococcus aureus, and Streptococcus pneumoniae [26], and commonly found in spreading disease causing organisms [11].…”

Molecular Epidemiology of Enterococcal Bacteremia in Australia

“…In 2004, we described a large single-strain outbreak of vanB E. faecium across several hospitals in Western Australia (17). Characterized as CC17 ST173 (34), once eradicated from the hospital environment this strain has not subsequently been isolated in Western Australia, nor was it detected in the AESOP 2011 bacteremia study. Furthermore, failure to isolate ST173 during long-term follow-up screening of previously colonized patients suggests the strain no longer had a selective advantage once outside the hospital environment.…”

Human and Swine Hosts Share Vancomycin-Resistant Enterococcus faecium CC17 and CC5 and Enterococcus faecalis CC2 Clonal Clusters Harboring Tn 1546 on Indistinguishable Plasmids

“…It includes representative isolates of VRE recovered from swine and healthy humans in national surveillance studies conducted in Portugal and Denmark (1995 to 2008) (references 17,26,35,37, and 38 and this study), strains widespread among swine from Switzerland and Spain (5,22), and the first VRE isolates recently recovered from animals in the United States (11). For comparison, we included a large and well-typed collection of clinical VRE isolates (140 E. faecium and 50 E. faecalis isolates) recovered from 23 countries, including Portugal, Spain, Denmark, and the United States, during the last 3 decades, most of which had caused hospital outbreaks (12,16). Testing of susceptibility to 12 antibiotics was performed either by E strip (bioMérieux, Solna, Sweden) or by a standard agar dilution method following recommended guidelines of the manufacturer or CLSI (6).…”