Diagnostic accuracy of buffy coat culture compared to total blood culture in late-onset sepsis of the newborn

Clinical value of repeat blood cultures in neonatal patients receiving antibiotic treatment

OBJECTIVE

Retrospective database study to determine the clinical usefulness of repeat blood cultures in antibiotic-treated neonates.

METHODS

Data regarding blood culture indication and findings for patients admitted to a neonatal intensive care unit (NICU) over a 2-year period were obtained from the hospital database. Repeat blood culture was defined as culture performed <7 days from initial testing in a patient receiving antibiotic treatment.

RESULTS

Repeat cultures made up 21.3% of all blood cultures originating in the NICU (500/2352 cultures; 338 initial positive cultures; 210 patients). The most common indications for repeat culture were follow-up of clinically well babies with previous positive culture findings and the development of new symptoms. The majority of culture findings were negative (60.2%), with 7.2% indicating the presence of a new pathogen. Cultures repeated on day 5 were significantly more likely to reveal a new pathogen than those repeated on days 1-4.

CONCLUSIONS

Repeat blood cultures in neonatal patients who have developed new symptoms >4 days after initial testing may be beneficial. The use of repeat blood culture is not recommended for any other indication.

Can sTREM-1 predict septic shock & death in late-onset neonatal sepsis? A pilot study

BACKGROUND AND OBJECTIVES

The transmembrane glycoprotein TREM-1 triggers an inflammatory response. Its soluble fraction (sTREM-1) has been shown to have diagnostic accuracy for late-onset neonatal sepsis (LONS). Until now, the potential of sTREM-1 to predict septic shock and/or death in septic neonates has not been explored. This study obtained estimates of the incidence and prevalence of septic shock and/or death in septic neonates for future sample size calculations for confirmatory studies and evaluated the feasibility of using sTREM-1 as a predictor of septic shock and/or death in neonates with LONS criteria.

STUDY DESIGN

A pilot study with a cross-sectional design was performed from May 1(st) to October 31(st), 2012. The participants were hospitalized neonates who, after three days of life, were diagnosed as having LONS. Plasma sTREM-1 was quantified by ELISA. The main outcome measurement was the development of septic shock and/or death.

RESULTS

Of 71 eligible subjects, nine (12.7%) progressed to septic shock and/or death. In the LONS-Non-Shock group, the sTREM-1 median and interquartile range (IQR) plasma value were 10 (10 to 70) pg/mL. In the LONS & Shock/Death group, the values were 567 (260 to 649) pg/mL. These values were significantly different (Mann-Whitney's U test, p=0.001). A ROC curve for a proposed sTREM-1 cut-off value of 300 pg/mL exhibited an area under the curve of 0.884 (95% CI=0.73 to 1.0; p<0.0001), with a sensitivity of 0.78 (95% CI=0.46 to 0.94) and specificity of 0.97 (95% CI=0.92 to 0.99); PPV would be 0.78 (95% CI=0.46 to 0.94) and NPV 0.97 (95% CI=0.92 to 0.99).

CONCLUSIONS

In neonates with LONS, sTREM-1 has the potential to provide an excellent predictive value for septic shock/death. Larger sample sizes are needed to identify the optimal cut-off value of plasma sTREM-1 for this diagnosis and to provide diagnostic accuracy measures.