Multiplex PCR pathogen detection in two severely burned patients with suspected septicemia

The case studies reported in this article strive to illustrate the clinical value of multiplex polymerase chain reaction (PCR)-based pathogen detection in patients with burn sepsis. Adult (age ≥18 years) burn patients (≥20% TBSA) presenting with signs and symptoms of burn sepsis were enrolled into a prospective, observational trial. Patients received PCR testing in parallel to routine blood cultures. The authors report two cases in which PCR was used to rapidly detect pathogens in whole blood from burn patients with suspected septicemia. PCR identified Escherichia coli in 5.8 hours in case 1. Blood and sputum cultures required 17 hours for Gram stain results. Empiric ceftriaxone therapy was initiated. Blood cultures required an additional 18 hours to identify the same pathogen detected by PCR. Ceftriaxone was replaced with ciprofloxacin for improved coverage. Follow-up antimicrobial susceptibility results revealed intermediate ciprofloxacin resistance. Meropenam therapy was initiated. In case 2, PCR detected Pseudomonas aeruginosa in 5.45 hours while blood cultures remained negative. Respiratory cultures became positive for P. aeruginosa 2 days later. Serial PCR samples continued detecting P. aeruginosa despite negative blood cultures and appropriate antimicrobial therapy. The patient later became hypotensive and coagulopathic and expired. For both patient cases, PCR identified high-risk pathogens faster than culture methods. In the second patient case, PCR identified the presence of pathogen DNA despite negative cultures before the onset of septic shock and presumptive disseminated intravascular coagulation. These results warrant further investigation to determine the clinical significance of pathogen DNA in burn sepsis.