Role of multiple site blood cultures to document the clearance of bacteremia in neonates

Double Blood Culture Policy Is More Effective Than Single In Neonatal Intensive Units

Aim: Blood culture (BC) sampling and antibiotic administration are common practices in Neonatal Intensive Care Units(NICUs). However, false positive BC results might affect clinician’s decision and lead to inappropriate antibiotic treatments. The aim of this study was to investigate the effect of double culture on clinical application. Material and Methods: The study was conducted retrospectively. The blood culture results of the patients admitted to the NICU between 2016-2019 were analyzed. Considering sepsis before 2017, we took only one sample from the patient. After this period, we started to take double blood cultures. Time frames of BCs were investigated to two groups as early and late onset sepsis fistly, and then subgroups as; a-) Group 1, BCs in the first 24 hours, b-)Group 2, between 24 to 72 hours, and c-)Group 3, after 72 hours. Results: Total of 1747 BC samples were taken in study. Majority of BCs were in Group 3(62%). Male/female ratio was 1.3:1. Staphylococcus Epidermidis(S. Epi) was major source for the contamination. But, by taking dBCs, we were able to eliminate most S.Epi contamination in Group 2 (11%vs.3%) and in Group 3(41%to14%). We were able to identify some resistant Gr(-) pathogens in one arm although the other arm was negative, by taking dBC. Conclusions: Our study indicates that dBC policy in NICUs could help to clinicians for judicious decision in antibiotic use and decrease unnecessary antibiotic exposure of infants. Also it could be enable to detect some highly pathogen microorganism easily. Key words: Newborn, Septicemia, Blood culture, Coagulase Negative Staphylococci, contamination

Soluble CD14 subtype (sCD14-ST) as biomarker in neonatal early-onset sepsis and late-onset sepsis: a systematic review and meta-analysis

Background

Early diagnosis of bacterial sepsis in neonates is hampered by non-specific symptoms and the lack of rapid responding laboratory measures. The biomarker soluble CD14 subtype (sCD14-ST) seems promising in the diagnostic process of neonatal sepsis. In order to evaluate the differences in diagnostic accuracy of sCD14-ST between early onset sepsis (EOS) and late onset sepsis (LOS) we assessed this systematic review and meta-analysis.

Results

Twelve articles were included in the systematic review and 10 in the meta-analysis. There was a high risk of bias on patient selection, index test and/or flow and timing. The overall quality of the included studies was moderate.

At sepsis onset a consequently higher level of sCD14-ST was found in septic neonates compared to healthy controls with significant higher levels in LOS compared to EOS. In the first 24 h after sepsis onset a significant increase in pooled means of plasma sCD14-ST levels was seen in EOS (t(71.6) = 7.3, p < .0001) while this was not seen in LOS or healthy controls. Optimal cut-off values ranged from 305 to 672 ng/l for EOS cases versus healthy controls. The pooled sensitivity was 81% (95%CI: 0.76–0.85), the pooled specificity was 86% (0.81–0.89) with an AUC of 0.9412 (SE 0.1178). In LOS optimal cut-off values ranged from 801 to 885 ng/l with a pooled sensitivity of 81% (0.74–0.86) and a pooled specificity of 100% (0.98–1.00). An AUC and SROC was not estimable in LOS because of the low number of studies.

Conclusions

sCD14-ST is a promising and rapid-responding diagnostic biomarker for EOS and LOS. The difference in pooled means between EOS and LOS underlines the importance to consider EOS and LOS as two different disease entities, requiring separate analysis in original articles and systematic reviews.

Electronic supplementary material

The online version of this article (10.1186/s12865-019-0298-8) contains supplementary material, which is available to authorized users.

Serial C reactive protein values predict sensitivity of organisms to empirical antibiotics in neonates: a nested case-control study

BACKGROUND

It is common clinical practice to repeat serum C reactive protein (CRP) estimation in the first 48 h after starting empirical antibiotics for neonatal sepsis. The change in CRP is believed to indicate whether the empirical antibiotics are appropriate or not, but there is little evidence to support this practice.

METHODS

This was a nested case-control study on neonates with suspected sepsis (clinical signs+baseline CRP >10 mg/L). We drew samples for serum CRP at baseline and at 24, 36 and 48 h after starting empirical antibiotics and stored them at -20°C. Those with positive blood cultures were enrolled into two groups: those who had received empirical antibiotics to which the organism was sensitive ('sensitive') and those who had received antibiotics to which the organism was resistant ('resistant'). Stored samples of these subjects were assayed for CRP. Repeated CRP values were compared between groups by mixed linear models. We evaluated change in CRP from baseline as a diagnostic test for identifying empirical use of sensitive antibiotics.

RESULTS

We enrolled 45 and 44 subjects in 'sensitive' and 'resistant' groups, respectively. In the 'resistant' group, median CRP increased with time but decreased in the 'sensitive' group. Decline in CRP by 48 h identified the use of antibiotics to which the organism was sensitive with 89% sensitivity and 80% specificity.

CONCLUSIONS

Serial CRP values in the first 48 h of antibiotic therapy help to predict whether the causative organism is sensitive to the empirical antibiotics administered.

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.

Rapid real-time nucleic Acid sequence-based amplification-molecular beacon platform to detect fungal and bacterial bloodstream infections

Bloodstream infections (BSIs) are a significant cause of morbidity and mortality. Successful patient outcomes are diminished by a failure to rapidly diagnose these infections and initiate appropriate therapy. A rapid and reliable diagnostic platform of high sensitivity is needed for the management of patients with BSIs. The combination of an RNA-dependent nucleic acid sequence-based amplification and molecular beacon (NASBA-MB) detection system in multiplex format was developed to rapidly detect medically important BSI organisms. Probes and primers representing pan-gram-negative, pan-gram-positive, pan-fungal, pan-Candida, and pan-Aspergillus organisms were established utilizing 16S and 28S rRNA targets for bacteria and fungi, respectively. Two multiplex panels were developed to rapidly discriminate bacterial or fungal infections at the subkingdom/genus level with a sensitivity of 1 to 50 genomes. A clinical study was performed to evaluate the accuracy of this platform by evaluating 570 clinical samples from a tertiary-care hospital group using blood bottle samples. The sensitivity, specificity, and Youden's index values for pan-gram-positive detection and pan-gram-negative detection were 99.7%, 100%, 0.997 and 98.6%, 95.9%, 0.945, respectively. The positive predictive values (PPV) and the negative predictive values (NPV) for these two probes were 100, 90.7, and 99.4, 99.4, respectively. Pan-fungal and pan-Candida probes showed 100% sensitivity, specificity, PPV, and NPV, and the pan-Aspergillus probe showed 100% NPV. Robust signals were observed for all probes in the multiplex panels, with signal detection in <15 min. The multiplex real-time NASBA-MB assay provides a valuable platform for the rapid and specific diagnosis of bloodstream pathogens, and reliable pathogen identification and characterization can be obtained in under 3 h.