Every hospital is faced with influenza-like illness (ILI) patients during the winter months. These ILI patients present at the emergency department with viruses such as enterovirus, coronavirus, rhinovirus, adenovirus, parainfluenza and metapneumovirus. Many objective findings, such as chest x-ray, leukocytosis, required oxygenation and fever, are duplicated in both viral and bacterial pathogens causing pneumonia. The incidence of viral pneumonia from ILI is estimated at 100 million cases annually. Antibiotics are not beneficial for viral infections and may lead to harm when inappropriately prescribed.
Traditionally, diagnosis of a respiratory infection occurs by symptom observation, viral and bacterial culturing, and antigen testing. Disadvantages to these methods are long turnaround times due to the required time for growth and inaccurate diagnosis due to false-negative results (antigen testing). Beginning in 2006, hospitals started using methods of syndromic testing to diagnose viral and atypical bacterial respiratory infections.
Various syndromic testing methods utilizing multiplex polymerase chain reaction (PCR) respiratory panels are available on the market in the United States, which can expand identification beyond influenza. These instruments can identify different viruses and atypical bacteria (e.g., Mycoplasmapneumoniae and Chlamydiapneumoniae) from a respiratory source and the turnaround time of the test can be as rapid as one hour. The primary advantage of this tool is the rapid identification of potential infecting viruses or atypical organisms, which may assist in the initiation or de-escalation of antimicrobial therapy. Infections such as Clostridium difficile from overuse of antibiotics can be averted through accurate diagnosis of the infection.
Palomar Health’s physician-led multidisciplinary committees have been instrumental in providing nationally recognized, award-winning care to our patients. One of those committees, the Palomar Health Antimicrobial Stewardship Program (ASP) committee (comprised of physicians, pharmacists, nurses, a microbiologist, information technologist and infection control nurse) examined an issue concerning the lag time in respiratory culture test results.
The process involved evaluating the respiratory culture collection, courier pick up, deliver to off-site university laboratory, and lag time for testing and dissemination of result to the ordering provider. In trying to develop a better process to decrease resulting lag time, it was discovered that utilizing an offsite laboratory increased the overall cost of the test four-fold. The ASP committee approved the use of the Biofire Respiratory Pathogen Array 2 in the house to enhance detection of viral and atypical pathogens, decrease the resulting lag time, and decrease the cost of offsite testing. The decision to use Biofire versus other available PCR testing methods was due to the rapid, resulting turnaround time of one hour. The Biofire Respiratory Pathogen Array 2 identifies 16 different viruses and four atypical pathogens from a nasopharyngeal swab (pathogens included below).
• Viruses: Adenovirus, Coronavirus (HKU1, NL63, 229E, OC43), Human metapneumovirus, Human rhinovirus/ enterovirus, Influenza A (H1, H3, H1-2009) and B, Parainfluenza virus (1, 2, 3, 4),Respiratory syncytial virus
• Bacteria: Bordetellaparapertussis, B. pertussis, C. pneumoniae, M. pneumoniae
The ASP committee developed and approved usage criteria for the BiofireRespiratory Pathogen Array 2 test for a patient exhibiting signs and symptoms of a respiratory infection and: (1) solid organ transplant on immunosuppression; (2) bone marrow tra nsplantation; (3) malignancy on chemotherapy; (4) critical illness requiring vasopressor or mechanical ventilation; or (5) recommendation by an infectious disease physician. Additionally, the patient must have a negative influenza nasal swab. With these restriction criteria, and availability of onsite testing, the annual estimated cost savings is $500,000.
Diagnostic stewardship is a powerful tool that antimicrobial stewardship programs may use for improved outcomes. Utilization of a respiratory PCR can rapidly identify infecting viruses or atypical organisms which may assist in the initiation or de-escalation of antimicrobial therapy. Pharmacists can play a key collaborative role in the development and implementation of respiratory multiplex PCR testing.