Florida's First VIM-Producing Pseudomonas: An Outbreak in a Long-Term Acute Care Hospital, 2017

Pseudomonas aeruginosa that produce Verona integron-encoded metallo-beta-lactamase (VIM) carry a resistance gene that can move between bacterial species — though how, and how often, is poorly understood. That is why finding even one patient colonized with a VIM-producing organism is a sentinel event: it calls for an investigation and careful handling of the patient.

The outbreak

On July 5, 2017, one such case turned up at a long-term acute care hospital (LTACH) in Orange County, Florida. The patient was put on contact precautions, and the whole facility was screened with rectal swabs in a point prevalence survey. The Florida Department of Health worked with the Tennessee Department of Health, the Southeast Regional Antibiotic Resistance Laboratory Network and CDC on resistance testing and genotyping.

From July 13 to September 22, six more patients screened positive — through three surveys two weeks apart and an enhanced surveillance system.

Colonized patients, screening surveys (PPS) and infection control steps, July–September 2017. CDC

The seven patients

One patient died about a month after colonization was found. No infections or complications from the colonization were reported. Of four isolates tested by pulsed-field gel electrophoresis, two had closely related patterns (more than 90% similar).

Why it matters

This was the first identification of VIM-producing P. aeruginosa in Florida. The organism was first reported in Marseilles, France, in 1996, and has since caused health care–associated infections in several countries. It spreads:

• on the hands of health care workers;
• through shared medical equipment;
• via surfaces and objects — bedside tables, IV poles, bedside commodes, sink drains.

What the hospital did

1. Set up enhanced surveillance of P. aeruginosa isolates.
2. Assessed infection control and response — hand hygiene, personal protective equipment.
3. Watched and reinforced environmental cleaning.
4. Put up outbreak notification signs and added it to discharge and transfer sheets.
5. Reviewed respiratory therapy practices.

A testing gap

Routine culture and susceptibility tests can show that P. aeruginosa is carbapenem-resistant, but not why. Finding the VIM gene takes PCR testing for resistance mechanisms, which most clinical labs don't do — though it is now available in all 50 states through CDC's Antimicrobial Resistance Laboratory Network (ARLN). Because such testing isn't done widely or uniformly, no one knows how common VIM-producing P. aeruginosa really is, in the community or in health care. Testing through the ARLN, and reporting high-priority resistance to public health authorities, can help define it and guide regional infection control.

Sources

Based on Rankin D, Caicedo L, Dotson N, Gable P, Chu A, "Notes from the Field: Verona Integron-Encoded Metallo-Beta-Lactamase–Producing Pseudomonas aeruginosa Outbreak in a Long-Term Acute Care Hospital — Orange County, Florida, 2017," MMWR volume 67, number 21, Centers for Disease Control and Prevention, with authors from the Florida Department of Health and CDC; a work of the United States government in the public domain. The imported copy stopped mid-paragraph; the missing description of the patients comes from CDC's syndicated copy of the report.