On June 1, 2018, the CDC published a report that described an outbreak of antibiotic resistant pneumonia at a long-term acute care hospital in Orange County, Florida. On July 5, 2017, one case of colonization with Verona integron-encoded metallo-beta-lactamase (VIM)–producing Pseudomonas aeruginosa was identified. VIM enzymes make bacteria resistant to carbapenem drugs.
VIM plasmids, pieces of DNA, are capable of transferring among bacterial species (e.g., from an E. coli to a non-Enterobacteriaceae like Pseudomonas aeruginosa). Because of this ability to easily move and share these genetic instructions, plasmids with resistance genes can help bacteria that cause treatable infections to develop new or different resistance mechanisms. However, the resistance mechanisms and frequency of resistance exchange is poorly understood. Thus, identification of colonization with VIM-resistant organisms is a sentinel event that warrants investigation and careful patient management.
In response, the patient was placed on contact precautions and a facility-wide point prevalence survey was conducted. To detect colonization of VIM-producing P. aeruginosa, rectal swabs were collected from patients at the long-term acute care hospital. The Florida Department of Health collaborated with the Tennessee Department of Health, the Southeast Regional Antibiotic Resistance Laboratory Network in Tennessee, and the CDC to conduct antimicrobial resistance testing and genotyping.
Between July 13 and September 22, 2017, six additional patients at the long-term acute care hospital screened positive for VIM-producing P. aeruginosa during three biweekly point prevalence surveys and an enhanced prospective surveillance system. The median length of stay at the long-term acute care hospital among the seven colonized patients was 40.5 days (range = 13–150 days), and their median age was 60 years (range = 40–68 years); 57 percent were men. No patients reported hospitalizations or medical procedures outside the United States. Among the seven colonized patients, six had tracheostomy tubes (including three with current diagnoses of ventilator-dependent respiratory failure), six had decubitus ulcers, and four were receiving hemodialysis. Five patients had received antibiotic therapy before specimen collection, and one patient died approximately one month after colonization was detected. No cases of infection or complications associated with VIM-producing P. aeruginosa colonization have been reported at the long-term acute care hospital.
This investigation documents the first identification of VIM-producing P. aeruginosa in Florida. VIM-producing P. aeruginosa was first reported in Marseilles, France, in 1996 and has since been documented in healthcare–associated infections in several countries. Transmission can occur horizontally via hand carriage by health care personnel, through shared medical equipment, and through fomites (e.g., bedside tables, intravenous poles, bedside commodes, and sink drains). Control measures include enhancing and reinforcing infection control processes and environmental disinfection. Measures taken in response to this outbreak investigation include (1) implementing an enhanced prospective surveillance program for P. aeruginosa isolates, (2) conducting infection control and response assessments (e.g., hand hygiene, personal protective equipment), (3) observing and reinforcing environmental cleaning practices, (4) implementing outbreak notification signage and patient discharge/transfer sheets, and (5) evaluating respiratory therapy processes.
Although carbapenem-resistant P. aeruginosa can be identified through routine culture and susceptibility testing, testing for mechanisms of resistance are not readily accessible. To detect the VIM-producing gene, additional antimicrobial resistance mechanism testing by polymerase chain reaction (PCR) must be conducted. Such testing is not routinely conducted at most clinical laboratories but is available now in all 50 states via the CDC’s Antimicrobial Resistance Laboratory Network (ARLN).
Routine surveillance or PCR testing for antibiotic resistance mechanisms among P. aeruginosa is not practiced widely or uniformly; thus, the true incidence and prevalence of VIM-producing P. aeruginosa in the community and the risk for transmission among patients in healthcare facilities is unknown. Testing for common carbapenemases via the ARLN has the potential to better define the epidemiology of carbapenem-resistant P. aeruginosa resistance mechanisms as well as inform the response to control transmission. Reporting of organisms with high-priority antibiotic resistance mechanisms to public health authorities can inform regional infection control and containment practices.
See the CDC Report
See also Medical Law Perspectives Report: Nursing Home Injuries: Acute Risks for Subacute and Skilled Nursing Care
See also Medical Law Perspectives Report: How Risky Is Going to the Hospital? The Dangers and Liabilities of Healthcare-Associated Infections
See also Medical Law Perspectives Report: Pneumonia Complications, Hospitalizations, Deaths: Risks and Liabilities