Transferring more than patients

Resistant gram negatives on the move

Emerging multidrug resistant gram negative bacteria continue to spread across the health care continuum, becoming entrenched in non-acute and long term care settings and threatening vulnerable hospital patients with untreatable infections. A recent report of reductions in several key healthcare-associated infections was tempered by rising concern about these pathogens, which include carbapenem-resistant Klebsiella pneumoniae and multidrug resistant Acinetobacter baumannii (MDR-Ab).

"I am concerned about the multidrug resistant gram negatives that we have no antibiotics to treat," says Denise Cardo, MD, director of the Division of Healthcare Quality Promotion at the Centers for Disease Control and Prevention. "We are seeing that as a big problem in outbreak investigations in several places. Again, patients are moving from one place to another like long-term care, acute care."

The CDC is currently investigating outbreaks in Illinois and Florida that involve colonized and infected patients and residents moving back and forth between various types of facilities. "This calls for a more regional approach — good data, good labs — but it is a challenge," Cardo says.

That challenge is all too clear to Nancy Johnson, MSN, RN, PHN, CIC

Infection Prevention Manager, Santa Clara Valley (CA) Medical Center.

"We had an unusual occurrence of a particularly resistant Acinetobacter baumannii," she tells Hospital Infection Control & Prevention. "We had three cases at that time that we were investigating as an outbreak. The antibiograms looked similar."

Looking at the patient charts, Johnson and fellow investigators found all three patients had been admitted to the hospital from an area skilled nursing facility.

"At that point we alerted the county that we were receiving patients from an acute care skilled nursing facility [SNF] that had very resistant [MDR-Ab strains]," she said. "We noted that there were additional ones when we started digging — we found that there was a cluster in our facility."

The investigation initially revealed eight patients infected with MDR-Ab, four of whom died. Four of the 8 patients had been admitted from the same SNF. The MDR-Ab strain was resistant to aztreonam, ceftriaxone, cefepime, ciprofloxacin, nitrofurantoin, and trimethoprim/sulfa.

This pattern with or without other antibiotic resistance occurred in 59% of A. baumannii isolates, making it a clearly identifiable subset of MDR-Ab and linking it to SNF-associated cases, Johnson reported this year in Baltimore at the annual conference of the Association for Professionals in Infection Control & Epidemiology.1

As the outbreak unfolded, 43 cases of MDR-Ab were identified between Dec 2009 and Dec. 2010. Nineteen (44%) of the cases were associated with the identified SNF. Thirteen (30%) had been in other SNFs, a dialysis center, or another acute care hospital in the past 30 days. Ten (23%) cases (colonization or infection) were acquired in the Santa Clara hospital and one (2%) was community acquired. The community acquired isolate was from a patient with a chronic leg ulcer.

"We continue to watch it," Johnson says. "It usually comes from another facility of some kind. It's emerging in other health care systems, not right from the home."

Johnson tracked MDR-Ab patient locations and found contact patterns of the admitted and hospital acquired cases. The hospital cases were clustered in the intensive care units, burn center, and rehabilitation units, she notes. The hospital acquired and healthcare-associated isolates were from endotracheal aspirates and urine cultures. Interventions included isolating and screening patients admitted from the SNF, taking environmental cultures, and enhancing cleaning. Infection control measures included contact precautions, staff education, reinforcement of hand hygiene and aseptic respiratory techniques, she adds. The measures quelled the outbreak, but the hospital continues to institute contact precautions for admissions from the SNF until MDR-Ab is ruled out.

"If the physician wants to remove them from contact precautions they have to clear them, which according to our policy is a urine culture, ET aspirate if they have a trach, and a rectal swab," she says. "If they come back negative they can come out of isolation."

Meanwhile, a public health investigation revealed MDR-Ab was endemic in the skilled nursing facility, which focused on improving hand hygiene.

"It wasn't just our hospital that was seeing it," she says. "We called other hospitals that share patients with us and alerted them to it, and in fact they were seeing an increase in the same organism with the same antibiogram — from this same SNF. It is definitely out there in the community."


  1. Johnson NA, Simpkins SM, Hipona P, et al. Abstract 1-003. Association for Professionals in Infection Control and Epidemiology. June 27-29, 2011. Baltimore, MD.