1589. CRP and PCT in Primary Care Patients with LRTI: Association with Microbiological Etiology
Session: Poster Abstract Session: Community Acquired Pneumonia
Saturday, October 10, 2015
Room: Poster Hall
  • IDWeek%202015%206.pdf (662.1 kB)
  • Background: LRTI is one of the most common reasons for encounter in primary care. CRP and PCT can be used as POCTs to aid in the diagnosis of LRTI but the association between these biomarkers and microbiological diagnosis has not been described in primary care patients. This study investigated the association between CRP and PCT levels and etiology of infection in patients presenting with LRTI in the GRACE (www.grace-lrti.org) Network of Excellence. 

    Methods: Patients presenting with LRTI were prospectively enrolled in 16 primary care networks in 11 European countries. Blood, sputum and NP flocked swabs, CRP and PCT were obtained at presentation and CXR was obtained within 7 days. Microbiological etiology was obtained using bacterial culture, PCR and serology, as appropriate. 

    Results: Microbiological, CRP and/or PCT results were available for 1832 subjects (84 with radiographically-proven CAP). 8 respiratory viruses and 5 bacterial pathogens were recovered. 38 (48%), 11 (14%), 31(39%) of CAP subjects had CRP <20, 20-50, >50mg/L, respectively. 88% of CAP subjects had PCT <0.5 μg/L. Most non-CAP subjects had low biomarker values with CRP <20 mg/L (75%) and PCT <0.1 μg/L (92%). Mixed infection were the most common etiology for CAP subjects with CRP <20 mg/L (21%) and >50 mg/L (48%) followed by H. influenzae  (13%) and rhinovirus (13%), respectively. Mixed infection was also the most common finding in CAP subjects with PCT <0.5 μg/L (23-50%); for those with PCT ≥0.5μg/L, rhinovirus was most common (66.6%). Influenza was not recovered in CAP subjects with CRP >50m/L or PCT >0.5 μg/L. Subjects with CRP 20-50mg/L (16.4%) and those with PCT 0.25-0.5 μg/L (28.6%) had the greatest proportion of influenza cases. In those with PCT ≥0.5 μg/L, rhinovirus was most common. 

    Conclusion: Mixed infections were the most common finding across biomarker concentrations. Most influenza cases did not occur in subjects with the highest biomarker levels, regardless of whether they had CAP. Further elucidation of the role of mixed infection in primary care patients with LRTI and the utility of biomarkers to differentiate between respiratory viruses in these patients is needed.

    Veronique Nussenblatt, MD, ScM, MHS1, Margareta Ieven, PhD2, Christine Lammens, BSc1, Samuel Coenen, MD, PhD1, Christopher Butler, MD, PhD3, Paul Little, MD, MBBS, MRCP4, Theo Verheij, MD PhD5 and Herman Goossens, MD, PhD1, (1)Laboratory of Medical Microbiology, University of Antwerp, Antwerp, Belgium, (2)University Hospital, Edegem, Belgium, (3)University of Oxford, Oxford, United Kingdom, (4)Aldermoor Health Centre, University of Southampton, Southampton, United Kingdom, (5)Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, Netherlands


    V. Nussenblatt, None

    M. Ieven, None

    C. Lammens, None

    S. Coenen, None

    C. Butler, None

    P. Little, None

    T. Verheij, None

    H. Goossens, None

    Findings in the abstracts are embargoed until 12:01 a.m. PDT, Wednesday Oct. 7th with the exception of research findings presented at the IDWeek press conferences.