2017年CIDに発表された、3施設 ( Chicago, Illinois, and 2 hospitals in Nashville, Tennessee) によるCAPとプロカルシトニンに関する報告。
Clinical signs of CAP, including ≥1 sign of acute infection (fever, chills, hypothermia, leukocytosis, leukopenia, altered mental status) and ≥1 sign of acute respiratory illness (cough, sputum production, chest pain, dyspnea, tachypnea, abnormal lung examination, respiratory failure).
First, 23% of patients enrolled in the EPIC study were not included in this analysis because serum specimens for PCT measurement were not available; this had the potential to introduce a selection bias, but measured clinical characteristics and detected pathogens were similar between the included and excluded patients.
Second, while some protocols recommend serial PCT measurements to guide antibiotic prescribing, we only measured PCT at the time of hospital admission.
Third, invasive diagnostic testing (eg, thoracentesis, bronchoscopy) was only utilized when deemed medically necessary by the treating physicians; study-dictated invasive tests may have resulted in more patients with an identified pathogen.
Fourth, all detected pathogens may not have represented causative agents for pneumonia; for example, viruses detected in NP/OP swabs may have represented infection limited to the upper airways or asymptomatic shedding.
Fifth, we sampled patients for pathogens at the time of hospital admission only; delayed bacterial pneumonias that developed after an initial viral infection would not have been detected with this sampling method.
Finally, all enrolled patients were hospitalized and we are unable to comment on PCT in outpatients with pneumonia.
Although no PCT threshold perfectly discriminated between bacteria and viruses, higher serum PCT strongly correlated with increased probability of a bacterial pathogen.
These data suggest that PCT could assist clinicians in evaluating for potential pathogens, but highlight that basing antibiotic prescribing decisions exclusively on PCT would result in a proportion of patients with bacterial pneumonia not receiving antibiotics.