Positive Blood Culture as a Marker of Sepsis and MODS Risk in Critically Ill Children A Narrative Literature Review

Utility of blood cultures in pneumonia patients admitted through the emergency department

Catheter-related thrombosis in critically ill children: Comparison of catheters with and without heparin bonding

Rapid identification of microorganisms from positive blood cultures in pediatric patients by MALDI-TOF MS: Sepsityper kit versus short-term subculture

Prediction of blood culture results by measuring procalcitonin levels and other inflammatory biomarkers

The present study aimed to investigate the relationship between the time to positivity (TTP) of blood cultures and the performance of short-term subculture for MALDI-TOF MS-based identification of microorganisms from positive blood cultures in pediatric patients. The study was conducted between April 2018 and July 2019 at a tertiary children's hospital in Eastern China and the TTP of all the blood cultures included was retrospectively collected at the same time. In total, 332 monomicrobial blood cultures were included in the study. Blood cultures that were identified at the genus level (score ≥ 1.700) by the short-term subculture protocol had shorter TTP (median TTP: 17.5h) than of those not identified (median TTP: 24.6h; P < 10-3). Those that were identified at the species level (score ≥ 2.000) by the short-term subculture protocol also had shorter TTP (median TTP: 16.7h) than of those not identified (median TTP: 21.7h; P < 10-3). ROC curve analysis indicated that the TTP cutoff value to the genus level of the short-term subculture protocol was 18.2h (area under the curve (AUC): 0.801; 95% confidence interval (CI) 0.741-0.861; P < 10-3). At the same time, the TTP cutoff value to the species level of the short-term subculture protocol was 18.1h (AUC: 0.747; 95% CI 0.694-0.800; P < 10-3). TTP is a convenient and valuable prognostic tool for the determination of the performance of short-term subculture for MALDI-TOF MS-based identification of microorganisms from positive blood cultures in pediatric patients.

Distinguishing coagulase-negative Staphylococcus bacteremia from contamination using blood-culture positive bottle detection pattern and time to positivity

Time to positivity of blood cultures in patients with bloodstream infections: A useful prognostic tool

Time to positivity of blood cultures in patients with bloodstream infections: A useful prognostic tool

ObjectiveTo determine the time to positivity (TTP) of blood cultures among infants with late-onset bacteraemia and predictors of TTP >36 hours.DesignRetrospective cohort study.Setting16 birth centres in two healthcare systems.PatientsInfants with...

Background and Objectives: Early diagnosis of candidemia is of vital importance in reducing mortality and morbidity. The main objective of the study was to determine the TTP (Time to Positivity) of different species of Candida causing blood- stream infection and to see whether TTP can help differentiate Candida glabrata which is frequently fluconazole resistant from Fluconazole sensitive Candida. Materials and Methods: TTP (Time to positivity) and AAT (Appropriate Antifungal therapy) were noted for Blood cultures becoming positive for Candida. Presence of Risk factors for candidemia like prolonged ICU stay, neutropenia, Total Paren- teral Nutrition (TPN), use of steroids , broad spectrum antibiotics, use of Central Venous Catheter, Foleys catheter were also analyzed. Results: The most frequent isolates were Candida parapsilosis, Candida tropicalis and Candida albicans. The median TTP for all Candida isolates in our study was 34 hours. The diagnostic sensitivity of TTP for detecting C. glabrata and C. tropicalis in patients with candidemia was 88% and 85% respectively. TTP showed that there was no difference in survival between TTP &lt;24 hrs. and &gt; 24hrs. Initiation of antifungal therapy &lt;24 hours and &gt; 24hrs after onset of candidemia had no association with survival. Conclusion: Longer TTP maybe predictive of C. glabrata while shorter TTP may be predictive of C. tropicalis. In our study we found that fluconazole resistant Candida causing blood stream infection is quite unlikely if the TTP of the isolate is &lt;48hrs.

Despite its well-established limitations, culture remains the gold standard for microbial identification in periprosthetic joint infection (PJI). However, there are no benchmarks for the time to positivity (TTP) on culture for specific microorganisms. This study aimed to determine the TTP for pathogens commonly encountered in PJI. This retrospective, multicenter study reviewed prospectively maintained institutional PJI databases to identify patients who underwent hip or knee revision arthroplasty from 2017 to 2021 at 2 tertiary centers in the United States and Germany. Only patients who met the 2018 International Consensus Meeting (ICM) criteria for PJI and had a positive intraoperative culture were included. TTP on culture media was recorded for each sample taken intraoperatively. The median TTP was compared among different microbial species and different specimen types. Data are presented either as the mean and the standard deviation or as the median and the interquartile range (IQR). A total of 536 ICM-positive patients with positive cultures were included. The mean number of positive cultures per patient was 3.9 ± 2.6. The median TTP, in days, for all positive cultures was 3.3 (IQR, 1.9 to 5.4). Overall, gram-negative organisms (TTP, 1.99 [1.1 to 4.1]; n = 225) grew significantly faster on culture compared with gram-positive organisms (TTP, 3.33 [1.9 to 5.8]; n = 1,774). Methicillin-resistant Staphylococcus aureus (TTP, 1.42 [1.0 to 2.8]; n = 85) had the fastest TTP, followed by gram-negative rods (TTP, 1.92 [1.0 to 3.9]; n = 163), methicillin-sensitive Staphylococcus aureus (TTP, 1.95 [1.1 to 3.3] n = 393), Streptococcus species (TTP, 2.92 [1.2 to 4.3]; n = 230), Staphylococcus epidermidis (TTP, 4.20 [2.4 to 5.5]; n = 555), Candida species (TTP, 5.30 [3.1 to 10]; n = 63), and Cutibacterium acnes (TTP, 6.97 [5.9 to 8.2]; n = 197). When evaluating the median TTP according to specimen type, synovial fluid (TTP, 1.97 [1.1 to 3.1]; n = 112) exhibited the shortest TTP, followed by soft tissue (TTP, 3.17 [1.4 to 5.3]; n = 1,199) and bone (TTP, 4.16 [2.3 to 5.9]; n = 782). To our knowledge, this is the first study to examine the TTP of common microorganisms that are known to cause PJI. Increased awareness of these data may help to guide the selection of appropriate antimicrobial therapy and to predict treatment outcomes in the future. Nonetheless, additional studies with larger cohorts are needed to validate these benchmarks. Diagnostic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Blood stream infections (BSI) are one of the serious and life threatening complications associated with high morbidity and mortality. Identification of patients without bacterial infections is an important component of antimicrobial stewardship. With the advances in the automated blood culture systems especially with the continuous monitoring systems, time to positivity (TTP) of blood cultures has been reduced drastically thereby allowing faster de-escalation of the antibiotics.: In this study, we have analysed the TTP of different bacterial isolates, and the effects of initiation of antimicrobials and blood volume on TTP. Adult patients with monomicrobial bacteraemia in an academic hospital were included retrospectively over a four-year period. Time to positivity was recorded for each positive sample. Information about the timing of blood sample collection i.e. before or after start of antibiotics was collected from the blood culture requisition form. The blood volume in the blood culture bottle is the virtual blood volume given by the Bact-Alert Virtuo instrument. A total of 38,606 blood culture samples that flagged positive from adult patients with suspected BSIs were included. 79% of the samples had a TTP of less than 24 hours and 15% of the samples had TTP of 24 to 48 hrs. Only 6% of the samples had TTP of more than 48 hours. Gram negative pathogens (Average TTP- 12.5hours) have shorter TTP when compared to Gram positive pathogens (Average TTP- 15.4 hours).With the use of modern automated blood culture systems, TTP can be used as a tool to guide the antimicrobial therapy and early de-escalation of the empirical antibiotics thereby reducing the emergence of antimicrobial resistance.

Background and aims: Blood culture (BC) remains gold standard for the evaluation and diagnosis of neonatal sepsis. Time when BC becomes positive and the type of microorganism isolated are crucial in deciding the antimicrobial management. Likely pathogenicity of organisms growing in BC could potentially be predicted based on the “time to positivity” (TTP). We aimed to estimate the predictive value of isolating a likely pathogenic organism depending on TTP; evaluate the aetiological trend and neonatal mortality rate due to culture-proven neonatal sepsis for over a decade and verify whether the application of a “36 hour rule” to discontinue empiric antibiotics in well newborn infants with negative BC would be safe.Methods: Retrospective review of BC results over a 14-year period from a regional neonatal unit in Ireland. Laboratory data were independently extracted in relation to BC results from the laboratory information management system (LIMS-iLAB). Neonatal mortality data were collected from multiple sources. Statistical analysis included logistic regression, chi-square, and Mann–Whitney U-test.Results: Over a 14-year period 11,432 neonatal BC specimens were incubated of which 605 (5.3%) turned positive. Overall, the commonest organism grown was coagulase-negative Staphylococcus (CoNS), 416 (68.8%). Main pathogenic organisms were Staphylococcus aureus 23 (3.8%), Enterococcus spp. 22 (3.6%), E.coli 21 (3.5%), group B Streptococcus (GBS) 18 (3.0%), and Klebsiella species 9 (1.5%). Gram-negative organisms had the shortest TTP, with Klebsiella spp. having a median TTP of 10 h and E. coli 11 h. For Gram-positives, GBS had a median TTP of 12 h, Enterococcus species 14 h, with S. aureus growing at a median time of 15 h. All of the Klebsiella spp. and other Coliforms were detected within 24 h, with, 95.2% of E.coli, 94.4% of GBS, 95.5% of Enterococci, and 95.7% of S. aureus, flagging positive in 24 h. Using logistic regression the omnibus test of the coefficients in the resulting model was significant (p < .001). Our observed coefficient (β) for TTP was 0.144; shorter the TTP higher was the likelihood of isolating a pathogenic organism, with an odds ratio (OR) of 1.155. We also report a relatively low blood culture proven sepsis-specific neonatal mortality rate of 0.403/1000 live births and in all such instances observed TTP was less than 24 h.Conclusion: Duration of this study exceeds that of most of the neonatal blood culture TTP analysis published to-date. A shorter TTP is an important adjunct to suggest the growth of a pathogenic organism while managing suspected neonatal sepsis. TTP if < 24 h per se would not necessarily confirm the growth of a highly pathogenic organism; however, if a positive growth is likely to happen for a significant neonatal pathogen, in more than 98% the TTP would be within 24 h. This offers the clinician more of negative predictive value than a positive one; when there is no growth in BC. Our observation on TTP reiterate the National Institute of Health and Care Excellence (NICE) guideline of discontinuation of empiric antibiotics after 36 h in and clinically well and BC negative newborn infants.

BackgroundTime to positivity (TTP) and differential TTP (DTP) emerge as diagnostic and prognostic tools for bloodstream infections (BSI) though specific cut-off values need to be determined for each pathogen. Pseudomonas aeruginosa BSI (PAE-BSI) is of critical concern, particularly in immunocompromised patients, due to high mortality rates. Catheter-related infections are a common cause, necessitating rapid and accurate diagnostic tools for effective management (source-control).MethodsUnicentric retrospective observational study analyzing the diagnostic utility and best cut-off values of time to positivity (TTP) and differential time to positivity (DTP) to identify catheter-related PAE-BSI and the association of TTP with 30-day mortality.Results1177 PAE-BSI cases TTP were included in the study. TTP was available in all episodes whereas DTP was available in 355 episodes. Breakthrough bacteremia disregarding the TTP, more than one positive blood culture or > 7 days with a catheter in place and both a TTP < 13h and a DTP > 2h were independently associated to catheter-related PAE-BSI. Secondly, lower TTP were significantly associated with higher 30-day mortality rates in both catheter-related and non-catheter-related PAE-BSI. For catheter-related infections, TTP < 14h exacerbated mortality among patients among patients in whom the catheter was not removed within 48h (OR 2.9[1.04–8]); whereas for other sources TTP < 16h increased mortality (OR 1.6[1.1–2.4]) particularly when the empiric antibiotic therapy was not active (OR 3.8[1.5–10]).ConclusionThese findings advocate for the routine use of TTP over DTP as a diagnostic tool to guide timely interventions such as catheter removal, thereby potentially improving patient outcomes in PAE-BSI. Moreover, lower TTP have also prognostic implications in both catheter-related and non-catheter-related infections.

Objective This study was to investigate the microbiological characteristics and the relationship between the time to positivity (TTP) of blood cultures and different bacterial species and to assess the clinical value of TTP in children with bloodstream infections (BSIs). Methods The TTP of all the blood cultures from children with suspected BSIs was retrospectively collected in 2016. The microbiological characteristics and the relationship between the TTP of blood cultures and different bacterial species were also analyzed. Results A total of 808 strains were isolated from 15835 blood cultures collected, and 145 (17.9%) were Gram-negative, 636 (78.7%) were Gram-positive, and 27 (3.3%) were fungi. The bacteria were divided into definite pathogens (174), possible pathogens (592), fungi (27), and contaminants (15). The average TTP of all positive blood cultures was 30.97 and ranged from 3.23 h to 92.73 h. The TTP of Gram-negative strains was significantly shorter than that of Gram-positive strains (P < 0.001) and fungi (P = 0.032). The mean TTP for E. coli (15.60 h) was shortest within the group of Gram-negative isolates, and the mean TTP for Streptococcus (17.34 h) within the group of Gram-positive isolates. Significant difference of the TTP was detected in methicillin-resistant vs methicillin-susceptible S. aureus, extended-spectrum beta-lactamases (ESBLs) positive vs negative Enterobacteriaceae, and extensive drug-resistant and non-XDR A. baumannii. The median TTP in patients with BSI was significantly shorter than in those without it (P < 0.001). ROC curve analysis indicated that the TTP cutoff value of CoNS, S. aureus, E. coli, and K. pneumoniae was 22.72 h, 19.6 h, 18.58 h, and 16.43 h, respectively, with most sensitive and specific predictor of BSIs. Conclusions Our data acknowledged that TTP is a valuable index for the early prognosis of BSIs. TTP not only provides additional utility as a general predictor of bacteria with smear result but also provides the implication of drug-resistant organisms.