The potential utility of real-time PCR of the 16S-rRNA gene in the diagnosis of neonatal sepsis

Novel Diagnostic Methods for Infective Endocarditis

Infective endocarditis (IE) remains a dangerous disease and continues to have a high mortality rate. Unfortunately, despite continuous improvements in diagnostic methods, in many cases, blood cultures remain negative, and the pathogen causing endocarditis is unknown. This makes targeted therapy and the selection of appropriate antibiotics impossible. Therefore, we present what methods can be used to identify the pathogen in infective endocarditis. These are mainly molecular methods, including PCR and MGS, as well as imaging methods using radiotracers, which offer more possibilities for diagnosing IE. However, they are still not widely used in the diagnosis of IE. The article summarizes in which cases we should choose them and what we are most hopeful about in further research into the diagnosis of IE. In addition, registered clinical trials that are currently underway for the diagnosis of IE are also presented.

Overinterpretation of findings in diagnostic accuracy studies of infectious diseases

OBJECTIVES

To assess the prevalence of overly positive interpretation - also called 'spin'- of results in diagnostic accuracy studies of infectious diseases and to identify suggestions for improvement.

METHODS

A PubMed search was performed to identify diagnostic accuracy studies of infectious diseases published between January and March 2019. Each article was assessed by two authors independently to identify study characteristics and forms of actual and potential overinterpretation. 'Actual overinterpretation' was defined as conclusions that were not based on the study aims or conclusions that were more favourable than was justified by the study findings. There are other practices that may result in the overinterpretation of study findings and these have been described as 'potential overinterpretation'.

RESULTS

The final analysis included 120 studies. Favourable or promising recommendations were made in the main text of 101 (84%) of the included studies. Evidence of actual overinterpretation (spin) was found in 30 (25%) articles, with 22 studies reporting a conclusion that did not match the study aims and 56 studies with a more positive conclusion in the abstract than in the main text. All analysed studies exhibited at least one form of potential overinterpretation, with was most commonly a lack of sample size calculation (n = 109, 91%) and not reporting a null hypothesis (n = 115, 96%).

CONCLUSIONS

Evidence of overinterpretation of results was found in a third of the included studies. We propose possible interventions to prevent overly positive interpretation of results in diagnostic accuracy studies.

Systemic Candidosis Diagnostic Test with Candida Score and Monocyte Count in Premature Infants with Late-Onset Sepsis: Research in Low Resources Country

Abstract Introduction: Candida is the cause of most systemic fungal infections that plays a role in the pathophysiology of sepsis in newborns, especially in premature infants with late-onset sepsis. The candida score can be used to assess the occurrence of systemic candidosis where a candida score 2.5 can accurately identify patients who are at high risk for candidiasis infection. Monocytes also play an important role in preventing candida invasion. Materials and methods: This study used a cross sectional research design. Data was collected from premature infants with late-onset sepsis being suspected of systemic candidosis in neonatology inpatient ward. It was submitted from the period of November-December 2021. It takes a minimum of 31 samples to meet the criteria to process and analyze the data. The data obtained were processed and analyzed using the Receiver Operating Characteristic (ROC) method to obtain the Area Under Curve (AUC) value. Based on the AUC curve, the search for the most optimal intersection is carried out to obtain the sensitivity and specificity values. Results: Of the 31 research subjects, the number of subjects with positive PCR results was 27 (76.93%) while negative were 4 respondents (12.9%). The mean value of PCR density in the positive group of subjects was 76.93 and the range was 40.23 122.78. Meanwhile, in the group of subjects who were negative, the PCR density value was 0. The results of the candida score diagnostic test showed that the sensitivity obtained was 81%. Higher sensitivity and specificity 70% were found in the combined examination of candida scores and monocyte counts according to cut-off compared with separate examinations. Conclusions: The combined examination of candida score and monocyte count can be used as a diagnostic test for systemic candidosis in premature infants with late-onset sepsis, and could be used to consider the initiation of empirical antifungal therapy, either prophylactically or therapeutically, especially in limited laboratory facilities in Indonesia.

Molecular Methodologies for Improved Polymicrobial Sepsis Diagnosis

Polymicrobial sepsis is associated with worse patient outcomes than monomicrobial sepsis. Routinely used culture-dependent microbiological diagnostic techniques have low sensitivity, often leading to missed identification of all causative organisms. To overcome these limitations, culture-independent methods incorporating advanced molecular technologies have recently been explored. However, contamination, assay inhibition and interference from host DNA are issues that must be addressed before these methods can be relied on for routine clinical use. While the host component of the complex sepsis host–pathogen interplay is well described, less is known about the pathogen’s role, including pathogen–pathogen interactions in polymicrobial sepsis. This review highlights the clinical significance of polymicrobial sepsis and addresses how promising alternative molecular microbiology methods can be improved to detect polymicrobial infections. It also discusses how the application of shotgun metagenomics can be used to uncover pathogen/pathogen interactions in polymicrobial sepsis cases and their potential role in the clinical course of this condition.

Determining the Clinical Utility of 16S rRNA Sequencing in the Management of Culture-Negative Pediatric Infections

The use of 16S rRNA sequencing in culture-negative infections has improved identification of bacterial pathogens in select scenarios, but its clinical impact requires further elucidation, especially in the pediatric population. This retrospective study aims to determine the clinical utility of 16S rRNA sequencing on the clinical management of pediatric culture-negative infections in our institution. Significant clinical utility was identified in 30 (40.5%) of 74 clinical samples (p < 0.0001). Of all specimens, pulmonary samples yielded the most clinical utility (n = 9, 30%), followed equally by joint fluid (n = 6, 20%) and bone (n = 6, 20%), with no difference between fluid and fresh tissue specimens (p = 0.346). Although the difference was not statistically significant (p = 0.4111), the overall use of broad-spectrum coverage was decreased. The median number of antibiotics was decreased from two to one (p < 0.0001) based on 16S rRNA sequencing results. The results suggest that 16S rRNA sequencing has a significant impact on decreasing the number of antibiotics used in the treatment of pediatric culture-negative infections. 16S rRNA sequencing performed on pulmonary specimens has the highest likelihood of identifying a pathogen compared to other specimen types. Additional cost–benefit analysis needs to be completed to further determine clinical benefit.

The Accuracy of 16S rRNA Polymerase Chain Reaction for the Diagnosis of Neonatal Sepsis: A Meta-Analysis

Objective

To determine the accuracy of 16S rRNA polymerase chain reaction (PCR) for the diagnosis of neonatal sepsis through a systematic review and meta-analysis.

Methods

Studies involving 16S rRNA PCR tests for the diagnosis of neonatal sepsis were searched in the PubMed, Medline, Embase, and Cochrane Library databases. The methodological quality of the identified studies was evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2), and the sensitivity, the specificity, the positive likelihood ratio (PLR), the negative likelihood ratio (NLR), the diagnostic odds ratio (DOR), and the area under the curve (AUC) of operator characteristic (SROC) curves were determined. Heterogeneity between studies was analyzed by metaregression. Stata 14.0 and Meta-disc 1.4 software were used for the analyses.

Results

This meta-analysis included 19 related studies. The analysis found a sensitivity of 0.98 (95% CI: 0.85-1), specificity of 0.94 (95% CI: 0.87-0.97), PLR of 16.0 (95% CI: 7.6-33.9), NLR of 0.02 (95% CI: 0.00-0.18), DOR of 674 (95% CI: 89-5100), and AUC of 0.99 (95% CI: 0.97-0.99). Metaregression analysis identified Asian countries, arterial blood in blood samples, and sample size > 200 as the main sources of heterogeneity. This meta-analysis did not uncover publication bias. Sensitivity analysis showed that the study was robust. Fagan's nomogram results showed clinical usability.

Conclusions

The results from this meta-analysis indicate that 16S rRNA PCR testing is effective for the rapid diagnosis of neonatal sepsis.