Major article
Outbreak of vanB vancomycin-resistant Enterococcus faecium colonization in a neonatal service

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Highlights

  • Bundled infection control interventions rapidly terminated vanB VREfm outbreak.

  • Closed environment of the neonatal service aided rapid and sustained eradication.

  • Active surveillance cultures and strain-typing (WGS, MLST) guided intervention.

Objective

To describe successful termination of an outbreak of vancomycin-resistant Enterococcus faecium (VREfm) colonization within a neonatal service.

Setting

Multisite neonatal intensive care unit and special care nurseries within a single health care service.

Participants

Forty-four cases of VREfm-colonized neonatal inpatients–including 2 clinical isolates (eye swab and catheter-urine specimen) and 42 screening isolates.

Interventions

Active surveillance cultures, patient isolation, contact precautions, enhanced environment cleaning, and staff and parent education. Whole genome sequencing and multilocus sequence typing were used to characterize the outbreak and refine infection control procedures.

Results

Peak prevalence of VREfm colonization across all sites was 31% upon discovery of the outbreak. Subsequent to the intervention, transmission was halted within 8 weeks and no further isolates of the outbreak strain have been detected as of 12 months following outbreak cessation. Environmental swabs revealed VREfm colonization of baby-weighing scales, a baby bath, and a pharmacy refrigerator within the neonatal intensive care unit. All isolates were of a single multilocus sequence type (sequence type 796) and highly clonal at the core genome level.

Conclusions

Bundled infection control interventions were effective in rapidly terminating a clonal outbreak of sequence type 796 VREfm colonization within a neonatal inpatient service. Strain-typing and active surveillance cultures were critical in guiding the management of this outbreak. The closed environment of a neonatal unit likely facilitated eradication of the patient and environment reservoirs of VREfm colonization.

Section snippets

Setting

Monash Newborn consists of a 54-bed level III NICU (Clayton, Melbourne, Australia) and 2 special care (level II) nurseries with capacity of 14 beds and 6 beds located at 2 separate campuses. A private special care nursery of 5 beds is colocated at the Clayton campus, but staffed and administered separately in a different facility from the NICU. Unwell or at-risk neonates are admitted directly after birth into either the NICU or special care nurseries (SCNs), depending upon the severity of their

Outbreak description

A total of 44 cases of VREfm carriage were detected between October 14, 2013, and January 10, 2014 (as shown in Fig 1). Twenty-five cases (57%) were at Clayton, the remainder occurring across the 3 satellite sites. The median baby age at detection of VREfm colonization was 22.5 days (range, 4-138 days). Median birth weight was 2,005 g (mean, 2,042 g; range, 725-4,300 g) and median gestational age was 33 weeks (mean, 33 weeks; range, 25-41 weeks) for 40 babies for whom data was available. The

Discussion

We describe a large outbreak of vanB ST796 VREfm in a neonatal setting that was successfully terminated by the application of contact precautions and enhanced cleaning. Previous neonatal outbreaks have been confined to the Northern Hemisphere, have included mostly vanA strains (only 1 report involving vanB2), and have mostly reported low rates of clinical infection as well as termination with combinations of infection control interventions, including active surveillance cultures, environment

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    This work was supported by a grant from the National Health and Medical Research Council of Australia (No. 1027874).

    Conflicts of interest: None to report.

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