Think prevention is expensive? Try infection
The cost of a single nosocomial outbreak was recently broken down into staggering detail by an economically minded clinician at Columbia University Hospital in New York City. The message to administrators: Think prevention is expensive? Try infection.
"A four-month outbreak—a third of a million dollars," said Patricia Stone, PhD, RN, a health services researcher at Columbia. "This outbreak costs the hospital $350,000, and that is a conservative estimate."
The expensive pathogen behind the outbreak was extended spectrum â-lactamase Klebsiella pneumoniae, which is often linked to hospital-acquired infections occurring in intensive care units. In this case, the setting was a neonatal intensive care unit (NICU), which had eight infected and 14 colonized neonates over a four-month period. The persistent outbreak ultimately resulted in closing the unit, bringing lost revenues into the economic picture on top of all the other expenses.1
"There were 14 infants that were not admitted to the unit during the outbreak period," she reported in Nashville at the annual meeting of the Association for Professionals in Infection Control and Epidemiology (APIC). "We looked at the lost revenue to the hospital in terms of those lost beds and the NICU closure."
The closed beds resulted in a revenue loss of $110,000. The infected babies who were admitted had a mean length of stay of 85.5 days, 48 days longer than a similarly risk-adjusted patient group using comparative data. At $590 a day, the attributable cost of increased stay for infected neonates totaled $229,000. Of course, costs associated with fighting the outbreak pushed the total higher, but the efforts revealed two NICU nurses with persistent hand carriage K pneumoniae due to long or artificial fingernails. The hospital has now banned fake and long nails.
"Economic evaluations like this increase understanding of the burden of outbreaks," Stone said. "Evidence such as this may encourage more effort and resources to be put in [infection] prevention. You start to be able to make evidence based arguments."
But will the cost figures be used to lobby administration for an enhanced investment in infection control resources?
"It’s being done as we speak," she told APIC attendees at a special session on pediatric infection control.
HCW Linked to Outbreaks Years Apart
Another study presented at the same session featured a similar case of a colonized worker, but with an unusual twist. A nurse with recurrent carriage of a strain of methicillin-resistant Staphylococcus aureus was linked to separate outbreaks two years apart.
Between Dec. 17, 1999, and Jan. 5, 2000, 13 infants in an NICU at Virginia Commonwealth University (VCU) Health System in Richmond were infected or colonized with MRSA. The index case was an 800 g infant delivered in an ambulance.2
"The first four cases were within 10 days of one another," said Lynn Reynolds, RN, infection control professional at VCU. "There were two deaths; one related to the [MRSA] bacteremia."
Eight babies were asymptomatically colonized in the umbilicus and/or nares. Before the source was discovered the infection control team went to great efforts to prevent further spread.
"Our interventions initially for the first two cases included placing infected infants on contact precautions," she said. "The infected infants were moved to the back row of the unit away from the main traffic stream. We cohorted staff and infants; we reinforced the wearing of gowns and gloves for staff and visitors. And of course, [we did] education of staff. Unfortunately, despite our early interventions, we continued to have more cases of MRSA bacteremia."
Additional interventions included weekly surveillance cultures of the nares and umbilicus of all babies in the NICU. MRSA-positive infants were treated with intranasal mupiricin. Thorough cleaning of the unit was done daily to prevent environmental contamination. Access to the unit was limited to one entrance, which was through the scrub area. Underscoring the severity of the situation, a security guard was placed at the entrance to ensure hand washing. Employees were cultured for the outbreak strain.
"We were able to identify more cases of infected and colonized babies even after our additional interventions were instituted," she said. "If nosocomial transmission continued, there was discussion that we would close the unit."
Nares swabs were obtained on 140 hospital workers and the two EMS workers who delivered the index case. All cultures were negative except for one taken from an NICU nurse. Her isolates were identical to the outbreak strain by molecular typing. Control strains from other units were different from the outbreak strain.
"Further investigation of the colonized health care worker revealed that she was also positive for MRSA [during] a 1997 NICU outbreak," Reynolds said. "At that time, she was treated with intranasal mupiricin and had a follow-up culture that was negative."
The colonized nurse directly cared for eight of the 13 infants who were infected or colonized in the outbreak. She had no underlying medical conditions. Interestingly enough, this health care worker’s colonizing strains from the 1997 outbreak and the 2000 outbreak were genetically identical. She was removed from the unit, retreated with intranasal mupiricin, and successfully decolonized. She was reassigned to a non-NICU unit. "Once the heath care worker was removed, we had no new cases of MRSA infection or colonization the two months that followed," Reynolds said.
However, the story doesn’t end there. The NICU nurse—one of the best on the unit—eventually left the hospital after the reassignment.
"[One] argument was that we should allow her to return to the unit because she was considered one of the best nurses in the unit," Reynolds said. "She was highly trained and skilled, and deeply committed."
But the risk of subsequent infections—and the morbidity, mortality, and costs they could entail—compelled the hospital to ban the nurse from the NICU.
"This outbreak illustrates the controversy that arises when health care workers are found colonized with multidrug-resistant organisms," she said.
Winning the RSV Season
In other research presented at the pediatric session, an infection control practitioner (ICP) detailed the development of a successful policy for preventing seasonal outbreaks of nosocomial respiratory syncytial virus (RSV).3
"There are various conditions that increase the risk of a person having severe or even fatal RSV infection," said Elizabeth Fuss, RN, MS, CIC, an ICP at Johns Hopkins Hospital in Baltimore. "[Those include] congenital heart disease, underlying pulmonary disease in children, and prematurity—and immunodeficiency and immune suppression at any age. Nosocomial transmission of RSV is very well described, and if you look in the literature among reported outbreaks, you can find mortality rates as high as 44%."
ICPs at Johns Hopkins started tracking nosocomial transmission of RSV in 1989.
"It’s a good think we did, because in 1990-91, we had a terrible [rate]: 20.2% of all RSV cases were acquired nosocomially," she said.
The two-stage control measures that were originally put in place in 1991 have continued to evolve in the hospitals 140-bed pediatric unit. Stage 1 begins when the first case of RSV is admitted each fall. The protocol requires obtaining RSV antigen testing and viral cultures on all children under age 6 who have been diagnosed with bronchiolitis or pneumonia. Stage 2 begins when five patients have been admitted with RSV and expands RSV antigen testing and viral cultures to all children under 6 with any respiratory symptoms. They stay under RSV precautions until the antigen is negative, which sometimes is only a few hours with the rapid testing, she said. A nosocomial case is defined as a child who develops RSV at least four days after admission. Stage two stays in affect until 10 days have passed without admission of a community-acquired case or discovery of nosocomial transmission.
1. Stone P, et al. Attributable costs of an extended spectrum â-lactamase Klebsiella pneumoniae outbreak in a NICU. Session 2401:Pedatrics. Presented at the Association for Professionals in Infection Control and Epidemiology conference in Nashville, Tenn; May 2002.
2. Reynolds R, et al. An outbreak of methicillin-resistant Staphylococcus aureus in a neonatal intensive care unit linked to a previous outbreak. Session 2401:Pedatrics. Presented at the Association for Professionals in Infection Control and Epidemiology conference in Nashville, Tenn; May 2002.
3. Fuss E, et al. Preventing nosocomial respiratory syncytial virus infection: Sustained effort pays off. Session 2401:Pedatrics. Presented at the Association for Professionals in Infection Control and Epidemiology conference in Nashville, Tenn; May 2002.