Diagnostic utility of postmortem fine-needle aspiration cultures

Microbiological cultures at autopsy have not proved to be very useful. In life, transthoracic and fine-needle aspirations of other tissues have provided better results. The aim of this prospective study was to assess the diagnostic utility of postmortem cultures obtained by fine-needle aspiration puncture (FNAP) of several tissues when punctures were performed in the immediate postmortem period.

Comparative analysis was performed between FNAP cultures and those obtained in life and by conventional autopsy. All adult autopsied patients who died at a general teaching hospital in a 3-year period were included. Clinical data, microbiological cultures before death, and pathologic data from autopsies of all patients were recorded, as were results of FNAP performed after death from the heart, right lower lung, liver, spleen, and other areas suspicious for infection. Cultures from the same sites were made at autopsy. Microorganisms were isolated and defined as infectious agents, colonizers, or contaminants according to standard criteria.

Ninety-two patients (59 men, 33 women) were included in the study; patients had a mean age of 67.7 years. There were five main diagnostic groups: neoplastic (n = 25), digestive (n = 15), respiratory (n = 14), circulatory (n = 10), and infectious diseases (n = 10). Infection was suspected in 47 patients (51.3%). Autopsy was performed 12 hours after death or later in 61% of patients. No significant differences were found in terms of contamination or colonization in relation to time between death and FNAP, time between death and autopsy, or microorganisms isolated. The sensitivity of FNAP and autopsy with respect to the isolation of infective microorganisms was similar (80.9% vs 87%), but FNAP was more specific (66.7% vs 44.4%). Age, sex, time between death and FNAP, clinical diagnosis, cause of death, and antimicrobial therapy did not influence the results significantly. Blood cultures gave the best results (specificity 84.4%) [corrected].

Fine-needle aspiration puncture performed in the immediate postmortem period adds relevant microbiological information to the clinicopathologic picture and provides higher specificity than autopsy cultures. Blood cultures are especially useful. When difficulties are associated with autopsy examination or in cases of selected clinical conditions, FNAP can be an effective tool for the postmortem diagnosis of infection.