Usefulness of a molecular strategy for the detection of bacterial DNA in patients with severe sepsis undergoing continuous renal replacement therapy.
BACKGROUND
Sepsis is a major cause of morbidity and mortality in critically ill patients. Sepsis is associated with cell necrosis and apoptosis. Circulating plasma levels of DNA have been found in conditions associated with cell death, including sepsis, pregnancy, stroke, myocardial infarction and trauma. Plasma DNA can also derive from bacteria. We have recently implemented a method to detect bacterial DNA and, in the present study, we validated this technique comparing it to standard blood culture in terms of diagnostic efficacy.


METHODS
We examined a cohort of 9 critically ill patients with a diagnosis of severe sepsis and acute renal failure requiring continuous renal replacement therapy (CRRT). We analyzed bacterial DNA in blood, hemofilters, and ultrafiltrate (UF) by polymerase chain reaction amplification of 16S rRNA gene sequence analysis. Standard blood cultures were performed for all patients.


RESULTS
The blood cultures from 2 of the 9 (22%) patients were positive. However, bacterial DNA was identified in the blood of 6 patients (67%), including the 2 septic patients with positive blood cultures. In 9 (100%) patients bacterial DNA was found on the filter blood side, whereas in 7 (78%) subjects it was found in the dialysate compartment of the hemofilters. Bacterial DNA was never detected in the UF.


CONCLUSIONS
Using the 16S rRNA gene, the detection of bacterial DNA in blood and adsorbed within the filter could be a useful screening tool in clinically septic, blood culture-negative patients undergoing CRRT. However, the identification of the etiologic agent is not feasible with this technique because specific primers for the defined bacteria must be used to further identify the suspected pathogenic organisms.
Ratanarat
Ranistha
R
Department of Nephrology, Dialysis and Transplantation, St Bortolo Hospital, Viale Rodolfi 31, IT-36100 Vicenza, Italy.
Cazzavillan
Stefania
S
Ricci
Zaccaria
Z
Rassu
Mario
M
Segala
Chiara
C
de Cal
Massimo
M
Cruz
Dinna
D
Corradi
Valentina
V
Manfro
Stefania
S
Roessler
Eric
E
Levin
Nathan
N
Ronco
Claudio
C
D058186:Acute Kidney Injury / Q000628:therapy; D000328:Adult; D000368:Aged; D015331:Cohort Studies; D015169:Colony Count, Microbial / Q000379:methods; D016638:Critical Illness; D004269:DNA, Bacterial / Q000032:analysis* / Q000097:blood; D005260:Female; D017583:Hemodiafiltration / Q000379:methods*; D015312:Hemodialysis Solutions / Q000009:adverse effects / Q000032:analysis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000032:analysis* / Q000097:blood; D018805:Sepsis / Q000175:diagnosis* / Q000235:genetics / Q000382:microbiology / Q000628:therapy
D004269:DNA, Bacterial; D015312:Hemodialysis Solutions; D012336:RNA, Ribosomal, 16S