Laboratories Play Key Role in Combatting Hospital-Acquired Infections

Hospital-acquired infections (HAIs) are one of the most frequent complications for hospitalized patients. External pressures, including value-based reimbursement and national efforts to improve antibiotic stewardship, are causing hospitals to refocus their efforts on combatting HAIs. Evidence shows that a combination of infection control methods is most effective in bringing down HAI rates. But, increasingly laboratories have a central role to play in the investigation of cases of HAI.

A Sizable Issue
The U.S. Centers for Disease Control and Prevention (CDC) estimates there are about 722,000 HAIs in U.S. acute care hospitals annually and HAIs contribute to 75,000 patient deaths during their hospitalizations. HAIs not only can be life threatening, but they are also costly—nearly $10 billion annually in HAI. CDC data shows HAIs are declining, but they remain a pervasive problem given that on any given day, approximately one in 25 U.S. patients contracts at least one infection during their hospital care. Stubbornlyhigh HAI rates demonstrate the need for improved infection control in U.S. hospitals.

It is widely recognized that no one strategy can prevent all HAIs. Active surveillance—the systematic collection of samples from either all or high-risk asymptomatic patients—is thought to be an effective tool in hospitals’ arsenal to combat HAIs. A landmark study published in the Journal of the American Medical Association in June 2015 showed that a “bundle” of pre-surgical interventions can significantly reduce the incidence of surgical site infections due to Staphylococcus aureus. Central to this strategy was early nasal screening of patients undergoing total hip or knee replacements and cardiac operations. Yet, active surveillance is not as widely adopted as some in infection control would hope, in partbecause of mixed results of studies assessing the strategy’s clinical and cost effectiveness.

“There is not universal agreement about the impact active surveillance makes on infection rates,” Michael Pfaller, M.D., chief medical officer at T2 Biosystems, tells DTET. “Beyond that, if you are doing active surveillance, there is no standard approach. You must understand what your local problem is. Then you must decide whoto screen, how often, and what to do with the results.”

Currently, though, hospitals are feeling increased pressure to combat HAIs due to increasing concern over multidrug-resistant organisms, as well as financial incentives created by quality-based reimbursement. For U.S. fiscal year 2017, the Centers for Medicare & Medicaid Services is adopting new outcome measures for the safety domain in its Hospital Value-Based Purchasing Program, which intends to tie Medicare payments to the quality of inpatient care. There will be penalties for hospitals with too high rates of hospital-onset methicillin-resistant Staphylococcus aureus (MRSA) bacteremia and Clostridium difficile (C. diff) infection. Additionally, this safetydomain will carry increased weight in determining payments.

Role of Laboratories
This increasing pressure on hospitals provides an opportunity for clinical microbiology laboratories to play an important and strategic role in cutting HAIs. To do this, laboratories need to provide high-quality testing to identify pathogens and drug susceptibility. Aside from testing, though, John Daly, M.D., chief medical officer at the non-profit accreditor COLA, says microbiology labs can support infection control and surveillanceefforts in a number of important ways.

• The microbiology laboratory should serve as a consultant to the infection control program and designate a high-level person to serve on the infection control committee.
• Laboratories should monitor and report results of unusual findings suggestive of an outbreak or emergence of multi drug-resistant organisms.
• Make laboratory test data accessible, including for support of epidemiologic analysis.
• Store isolates that may require further testing for outbreak investigations.

In a recent review published June 7 in Frontiers in Microbiology experts from UniversidadeNova de Lisboa in Portugal offer additional suggestions.

• The director of the microbiology laboratory should be a clinician or a laboratory scientist with expertise in both infectious diseases and microbiology.
• Laboratory information systems are critical for aiding communication within the hospitals between clinicians and laboratories. These information systems need to be designed collaboratively to ensure effective communication and a positive impact on decision-making.
• Off-site location of laboratories can delay communication and can weaken infection prevention and antibiotic stewardship infrastructures.

Economics of Active Surveillance The literature remains conflicted regarding the most effective way to screen for HAIs and what portion of infection control efforts should be devoted to screening in vertical infection control efforts versus activities like hand hygiene, environmental cleaning, andother horizontal approaches.

Economic analyses can aid in evaluating the real-world feasibility of competing strategies. Two recent studies published in PLOS One examined cost of screening and demonstratethe complexity of trying to optimize active surveillance efforts.

Given that the majority of MRSA carriers are asymptomatic, a Canadian hospital compared risk-based screening for MRSA upon admission to universal MRSA screening. Patients with a positive polymerase chain reaction (PCR) test result were placed on contact precautions until hospital discharge or documented MRSA eradication. Costs for laboratory testing, contact precautions and infection control, private room costs,housekeeping, and length of hospital stay were compared.

The researchers found that risk factor-based MRSA screening assessed approximately 30 percent of admitted patients and cost the hospital over $780,000 annually. The universalscreening program screened approximately 83 percent of admitted patients and cost over $1.94 million dollars, with an estimated additional cost per patient screenedof $17.76. Costs for newly identified patients ranged from $599 for MRSA colonizationto $1,834 for MRSA bacteremia. The cost associated with a false positive screening testwas $526 per patient. As expected, the greatest increase in costs attributed to universalscreening was from laboratory costs ($397,750/year).

Other costs resulting from universal screening and the increased number of identified patients with MRSA colonization included revenue loss due to private room use, increased length of stay ($183,989/year), contact precautions ($125,067/year), and housekeeping($17,391/year).

The study, published July 27, showed that while the universal MRSA screening program was costly from a hospital perspective, it was not more clinically effective at reducingMRSA transmission than risk-based screening.

A separate study, published March 31, conducted a dynamic cost-effectiveness evaluation of strategies to combat C. diff. Interventions were assessed alone and “bundled” together. The interventions included aggressive C. diff testing; empiric isolation and treatment of suspected patients; improved adherence to hand hygiene and contact precautions; improved use of soap and water for hand hygiene; and improved environmental cleaning. Patients were tested for the presence of C. diff using a PCR test ($7.66 per test). Incidence of CDI ranged from 1.8 to 19.6 per 10,000 patient-days, depending onthe level of importation and transmissibility of C. diff modeled.

The University of Utah researchers found that when analyzed separately, hand hygiene compliance, environmental decontamination, and empiric isolation and treatment were the interventions that had the greatest impact on both cost and effectiveness. However, when assessing the series of bundled interventions, at intermediate levels of transmission, the bundle can reduce both inpatient costs and infections. At high levels of transmission, the bundle of interventions yielded a net cost savings. Optimal levels of each intervention did not provide an added benefit that outweighed the increased costcompared with intermediate levels.

Examination of Some Real-Life Surveillance Strategies Health care organizations with total MRSA clinical infections or blood-stream infections greater than .3 per 1,000 patient days should implement a MRSA control plan, according to a review study published June 15 in the Journal of Clinical Microbiology. The authors say that very low rates of clinical disease can be achieved with active surveillance testing and follow-up contact precautions or universal decolonization based on a review of studies involving more than5 million patients.

In implementing an active surveillance testing program, the University of Chicago (Illinois) researchers say the laboratory must structure their MRSA surveillance testing based on a combination of factors. These factors include test performance (sufficient sensitivity and specificity); test cost (expense to the laboratory); and result reporting time (that enable placing patients in contact precautions for 80 percent of the time theyare in the hospital).

“For example, a test with high cost and high specificity may actually be less expensive overall than one with low cost and low specificity since low specificity leads to unnecessary patient isolation, which can add as much as $30,000 of unnecessary isolation cost for every 10,000 tests done for each 1 percent loss of test specificity,” explains co-authorLance Peterson, M.D., from University of Chicago.

C. Diff Active surveillance testing for toxigenic C. diff may not be cost efficient in settings with low prevalence of colonization, according to a study published July 20 in BMC Infectious Diseases. Additionally, the Chinese researchers found that ICU-acquired toxigenic C. diff infections were not linked to detection at thetime of admission.

Rectal swabs were collected from 360 adult patients on admission to and at discharge from a 50-bed medical ICU of a major referral hospital in western China, (Aug. 2014 to Nov. 2014). Stools were collected from patients who developed ICU-onset diarrhea. Both swabs and stools were screened for toxin B gene (tcdB) by PCR. tcdB-positive samples werecultured for C. diff.

The researchers found that the prevalence of toxigenic C. diff colonization was 1.7 percent on admission and 4.3 percent at discharge. None of these patients developed diarrhea during their hospitalization in ICU, so all were classified as carriers. Only 1.1 percent of 360 patients had C. diff infection (10.7 cases per 10,000 ICU days) and none of these cases had toxigenic C. diff either on admission or at discharge,suggesting C. diff was acquired during their ICU stay.

Takeaway: Active surveillance testing is expected to become a more integral part of comprehensive hospital infection control plans, given mounting pressure to cut HAI rates. However, evidence suggests there may not be a one-size-fits-allapproach to designing these strategies.