DETECTION OF BACTEREMIA IN PATIENTS WITH FEVER AND NEUTROPENIA USING 16S RIBOSOMAL-RNA GENE AMPLIFICATION BY POLYMERASE-CHAIN-REACTION

Episodes of fever and neutropenia are common complications of treatmen t for cancer. The use of prophylactic and early empirical antibiotics has reduced mortality but decreases the sensitivity of diagnostic test s based on culture. The aim of this study was to determine the potenti al of a broad diagnostic approach (eubacterial) based on 16S rRNA gene amplification and sequencing to augment cultural methods of diagnosis of bacteraemia in patients with fever and neutropenia in a regional p aediatric oncology centre. One hundred eleven patient-episodes of feve r and neutropenia were evaluated during the study period, 17 of which were associated with positive blood cultures, as follows: Staphylococc us epidermidis (n =6 episodes), Enterococcus faecium (n=2), Streptococ cus sanguis (n=3), Streptococcus mitis (n=3), Staphylococcus aureus (n =1), Micrococcus spp. (n=1), and Stenotrophomonas maltophilia (n=1). E ubacterial polymerase chain reaction (PCR) detected bacterial DNA in n ine of 11 blood culture-positive episodes for which a sample was avail able for PCR; the species identified by sequence analysis were identic al to those derived from the conventional identification of the cultur ed isolates. Bacterial DNA was detected in 20 episodes (21 bacterial s equences) associated with negative blood cultures, 18 of which occurre d in patients who were receiving antibiotics at the time of sample col lection. The species presumptively identified by partial 16S rRNA gene sequencing were as follows: Pseudomonas spp. (n=6 episodes), Acinetob acter spp. (n=5), Escherichia spp. (n=3); Moraxella spp. (n=3); Staphy lococcus spp. (n=2); Neisseria spp. (n=1); and Bacillus spp. (n=1). Th e results of this study suggest that molecular techniques can augment cultural methods in the diagnosis of bacteraemia in patients who have been treated with antibiotics.