Enterococcus faecium is a leading cause of hospital-acquired infections around the world. Rising antibiotic resistance in certain E. faecium lineages leaves fewer treatment options. The overarching aim of this work was to determine whether restriction-modification (R-M) systems contribute to the structure of the E. faecium species, wherein hospital-epidemic and non-hospital-epidemic isolates have distinct evolutionary histories and highly resolved clade structures. R-M provides bacteria with a type of innate immunity to horizontal gene transfer (HGT). We identified a type I R-M system that is enriched in the hospital-epidemic clade and determined that it is active for DNA modification activity and significantly impacts HGT. Overall, this work is important because it provides a mechanism for the observed clade structure of E. faecium as well as a mechanism for facilitated gene exchange among hospital-epidemic E. faecium isolates.
Central line-associated bloodstream infections (CLABSIs) are one of the most dangerous and costly types of hospital-acquired infections. Incidence of CLABSI can be significantly reduced through proper aseptic techniques, surveillance, and active management strategies, including elimination of idle central line days. This quality improvement project examined two central venous catheter (CVC) cohorts. The institutional electronic health record (EHR) was utilized to generate a daily report indicating CVC utilization by patient care unit. The EHR was further scrutinized for documentation of appropriate indications for CVC use employing an appropriateness tool developed by the institutional vascular access team. Cohort 1 included 12 National Healthcare Safety Network-reportable units audited on a daily basis over a 4-week time period; cohort 2 included selected National Healthcare Safety Network-nonreportable units audited on a daily basis over a 2-week time period. Central venous catheters that did not meet defined indications as outlined by the institutional vascular access team's data collection checklist were escalated the same day to the unit clinical nurse manager for review and possible removal. The percentage of clinically nonindicated CVCs in cohort 1 fell by 65% over the 4-week period of daily audit and real-time feedback, with similar results noted for cohort 2. In conclusion, real-time audit and feedback regarding appropriate clinical indications for CVC use can result in decreased idle or nonindicated central line days, potentially contributing to decreased CLABSI rates. KEYWORDS Central line; central line-associated bloodstream infection; central venous catheter; hospital-acquired infection; peripherally inserted central catheter; real-time audit and feedback; utilization rates
9The gastrointestinal colonizer Enterococcus faecium is a leading cause of hospital-acquired 10 infections. Multidrug-resistant (MDR) E. faecium are particularly concerning for infection 11 treatment. Previous comparative genomic studies revealed that subspecies referred to as Clade 12A and Clade B exist within E. faecium. MDR E. faecium belong to Clade A, while Clade B 13 consists of drug-susceptible fecal commensal E. faecium. Isolates from Clade A are further 14 grouped into two sub-clades, A1 and A2. In general, Clade A1 isolates are hospital epidemic 15 isolates whereas Clade A2 isolates are isolates from animals and sporadic human infections. 16Such phylogenetic separation indicates that reduced gene exchange occurs between the 17 clades. We hypothesize that endogenous barriers to gene exchange exist between E. faecium 18 clades. Restriction-modification (R-M) systems are such barriers in other microbes. We utilized 19 bioinformatics analysis coupled with second generation and third generation deep sequencing 20 platforms to characterize the methylome of two representative E. faecium strains, one from 21Clade A1 and one from Clade B. We identified a Type I R-M system that is Clade A1-specific, is 22 active for DNA methylation, and significantly reduces transformability of Clade A1 E. faecium. 23Based on our results, we conclude that R-M systems act as barriers to horizontal gene 24 exchange in E. faecium and propose that R-M systems contribute to E. faecium subspecies 25 separation. 26 27 IMPORTANCE 28Enterococcus faecium is a leading cause of hospital-acquired infections around the world. 29Rising antibiotic resistance in certain E. faecium lineages leaves fewer treatment options. The 30 overarching aim of the attached work was to determine whether restriction-modification (R-M) 31 systems contribute to the structure of the E. faecium species, wherein hospital-epidemic and 32 non-hospital-epidemic isolates have distinct evolutionary histories and highly resolved clade 33 structures. R-M provides bacteria with a type of innate immunity to horizontal gene transfer 34 (HGT). We identified a Type I R-M system that is enriched in the hospital-epidemic clade and 35 determined that it is active for DNA modification activity and significantly impacts HGT. Overall, 36 this work is important because it provides a mechanism for the observed clade structure of E. 37 faecium as well as a mechanism for facilitated gene exchange among hospital-epidemic E. 38 faecium. 39 40 immune system that utilizes sequence complementarity between self (CRISPR RNAs) and 67 foreign nucleic acid to carry out its restrictive function, whereas R-M discriminates self from 68 foreign DNA by DNA methylation patterns. If the E. faecium clades encode different defense 69 mechanisms, they may not exchange genetic information freely, thereby facilitating and 70 maintaining phylogenetic separation. However, little is known about CRISPR-Cas and R-M in E. 71 faecium. Genomic analysis suggests that these systems could contribute to the observed clade...
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