Persistent bloodstream infection in children: examining the role for repeat blood cultures.

Repeat blood cultures are common in children after an initial positive culture. However, in contrast to adults, there are little data to help guide clinicians when a repeat culture is necessary to assess for persistent bacteremia. This study identifies factors associated with persistent bloodstream infections (BSI) in children to inform diagnostic stewardship. This cross-sectional study of children less than 18 years with at least one positive blood culture over a 5-year period utilized a generalized linear equation model to predict patient and microbial factors associated with persistent BSI defined as a positive blood culture with the same organism >48 hours after the index culture. Four hundred and five patients had 502 positive blood cultures yielding 556 organisms. Sixty-seven (13.2%) cultures were persistently positive. Anaerobic organisms (0/37) and Streptococcus species (0/104) were never recovered from repeat cultures. Staphylococcus aureus (OR 9.45, CI 5.15-17.35) and yeast (OR 78.18, CI 9.45-646.6) were statistically associated with persistent BSI. Patients with prior positive cultures (OR 1.44, CI 1.12-1.84) or a central venous catheter (OR 2.20, 95% CI 1.04-3.92) were also at risk for persistence. Immune dysfunction and elevated inflammatory markers at the time of the index blood culture were not significantly associated with persistence. Yeast or S. aureus were associated with persistent BSI, while anaerobes and Streptococcus species were never persistent. Patient characteristics at the time of blood draw did not predict persistence other than having previous positive blood cultures or a central venous catheter. These data can inform when repeat blood cultures have clinical value and reduce the risk of unnecessary blood draws in children. IMPORTANCE: We identify factors associated with bloodstream infection persistence in children. Our findings can help guide blood culture stewardship efforts in pediatric patients, especially in light of blood culture supply shortages.

Identification of Terrisporobacter muris isolated from human blood using whole-genome sequencing: A case report.

We describe a case of Terrisporobacter muris bacteremia in a critically ill elderly man with a sigmoid colonic perforation. Initially, MALDI-TOF MS identified the bacterium as T. glycolicus; however, 16S rRNA gene sequencing suggested the presence of T. glycolicus, T. mayombei, or T. petrolearius. Owing to the limitations of these methods in distinguishing among the Terrisporobacter species, we employed whole-genome sequencing, which revealed the involvement of T. muris in the infection. This case represents the second report of T. muris isolated from human blood culture and is the first to describe the clinical course of this infection. Our findings underscore the diagnostic utility of whole-genome sequencing in accurately identifying novel infectious agents.

Blood culture-negative Haemophilus endocarditis with large vegetation and the role of bronchoalveolar lavage: a case report.

Background: Blood culture-negative endocarditis (BCNE) is a significant condition associated with cardiac vegetation. It often occurs alongside sepsis, auto-immune diseases, or malignancies, posing a risk of vegetation and embolization. Notable pathogens include Haemophilus species, Cardiobacterium hominis, Eikenella corrodens, and Kingella species. Case summary: A 60-year-old white male Belgian patient presented with worsening dyspnoea. His recent medical history included chronic infections over the past 6 months. Transthoracic echocardiography revealed severe aortic stenosis with an 18 × 12 mm vegetation. Despite normal inflammatory markers and negative blood tests, 18F-fluorodeoxyglucose positron emission tomography with computed tomography excluded malignancy but identified multiple bilateral septic lung emboli. Sputum cultures and tuberculosis polymerase chain reaction (PCR) were negative. Facing the high risk of cardiac embolization and the need for aortic valve replacement, surgery was scheduled with an intraoperative bronchoalveolar lavage (BAL) to investigate the lung lesions. Intraoperative findings confirmed valvular lesions, and a biological aortic valve was successfully implanted. The post-operative course was uneventful. Aortic valve cultures and eubacterial PCR results were negative, but BAL cultures were positive for Haemophilus influenzae, indicating a chronic infection. The patient showed favourable progress at 6 months post-surgery with ongoing antibiotherapy. Discussion: This case illustrates a rare BCNE associated with large vegetation and symptomatic H. influenzae chronic respiratory tract colonization (CRTC). For BCNE cases with negative sputum cultures and suspected bacterial CRTC, we recommend performing BAL cultures for accurate diagnosis.

Evaluation of the Eazyplex®Candida ID LAMP Assay for the Rapid Diagnosis of Positive Blood Cultures.

Rapid molecular assays can be used to identify Candida pathogens directly from positive blood cultures (BCs) in a timely manner compared to standard methods using subcultures. In this study, the eazyplex®Candida ID assay, which is based on loop-mediated amplification (LAMP) and is currently for research use only, was evaluated for the identification of the most common fungal species. A total of 190 BCs were analysed. Sensitivity and specificity were 93.88% and 99.26% for C. albicans, 89.13% and 100% for Nakaseomyces glabratus (N. glabratus), 100% and 100% for Pichia kudravzevii (P. kudriavzevii), 100% and 100% for C. tropicalis, and 100% and 99.44% for C. parapsilosis. Sample preparation took approximately 11 min and positive amplification results were obtained between 8.5 and 19 min. The eazyplex®Candida ID LAMP assay is an easy-to-use diagnostic tool that can optimise the management of patients with candidemia.

An investigation of scattered light integrating collector technology for rapid blood culture sensitivity testing.

Introduction. Sepsis rates are increasing, with Gram-negative organisms representing a large proportion of bloodstream infections. Rapid antibiotic administration, alongside diagnostic investigations, is required for the effective management of these patients.Gap statement. Current diagnostics take ~48 h for a final report; therefore, rapid diagnostics are required.Aim. This study investigated a novel antibiotic sensitivity method, the scattered light integrating collector (SLIC), combined with a rapid identification method using matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) technology to determine if an accurate identification and susceptibility result can be provided within 4 h of a positive blood culture report.Methodology. A total of 47 blood cultures containing Gram-negative bacteria from 46 patients were processed using the MALDI-TOF Biotyper Sepsityper for identification directly from the blood and the SLIC instrument for susceptibility testing. All organisms were also tested using the current standard workflow used in the host laboratory. Categorical agreement (CA), major errors (MaEs) and very major errors (VMEs) were determined.Results. SLIC produced susceptibility results with a 71.9% CA, 30.6% MaE and 17.5% VME. The median difference in time to the final result was 44.14 (43 : 05-45 : 15) h earlier compared to the current method.Conclusion. We conclude that SLIC was unable to consistently provide sufficiently accurate antibiotic susceptibility results compared to the current standard method.

Development and validation of a predictive model for in-hospital mortality from perioperative bacteremia in gastrointestinal surgery.

PURPOSE: Prognostic scores require fluctuating values, such as respiratory rate, which are unsuitable for retrospective auditing. Therefore, this study aimed to develop and validate a predictive model for in-hospital mortality associated with gastrointestinal surgery for retrospective auditing. METHODS: Data from patients with bacteremia related to gastrointestinal surgery performed at Shizuoka General Hospital between July 2006 and December 2021 were extracted from a prospectively maintained database. Patients suspected of having a positive blood culture with contaminating bacteria or missing laboratory data were excluded. The remaining patients were randomly assigned in a 2:1 ratio to the deviation and validation cohorts. A logistic regression model estimated the odds ratios (ORs) and created a predictive model for in-hospital mortality. The model was evaluated using receiver operating characteristic (ROC) curves and calibration plots. RESULTS: Of 20,637 gastrointestinal surgeries, 398 resulted in bacteremia. The median age of patients with bacteremia was 72 years, and 66.1% were male. The most common pathogens were Staphylococcus (13.9%), followed by Bacteroides (12.4%) and Escherichia (11.4%). Multivariable logistic regression showed that creatinine abnormality (P < 0.001, OR = 3.39), decreased prognostic nutritional index (P < 0.001, OR = 0.90/unit), and age ≥ 75 years (P = 0.026, OR = 2.89) were independent prognostic factors for in-hospital mortality. The area under the ROC curve of the predictive model was 0.711 in the validation cohort. The calibration plot revealed that the model slightly overestimated mortality in the validation cohort. CONCLUSIONS: Using age, creatinine level, albumin level, and lymphocyte count, the model accurately predicted in-hospital mortality after bacteremia infection related to gastrointestinal surgery, demonstrating its suitability for retrospective audits.

Comparison of Zybio Kit and saponin in-house method in rapid identification of bacteria from positive blood cultures by EXS2600 matrix-assisted laser desorption ionization time-of-flight mass spectrometry system.

We evaluated the performance of Zybio EXS2600 matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) (Zybio Inc., Chongqing, China) for the identification of bacteria from positive blood culture (BC) bottles using Blood Culture Positive Sample Pretreatment Kit (Zybio Inc., Chongqing, China) in comparison to an in-house saponin method. Following a positive signal by the BACTEC™ FX system, confirmation of identification was achieved using subcultured growing biomass used for MALDI-TOF MS analysis. A total of 94 positive BC bottles with 97 bacterial isolates were analyzed. The overall identification rates at the genus and species levels for the saponin method were 89.7% (87/97) and 74.2% (72/97), respectively. With the Zybio Kit, 88.7% (86/97) and 80.4% (78/97) of microorganisms were correctly identified to the genus and species levels, respectively. The saponin method identified 65.3% (32/49) of Gram-positive bacteria at the species level, whereas the Zybio Kit achieved a higher species-level identification rate of 79.6% (39/49) (p = 0.1153). The saponin method with additional on-plate formic acid extraction showed a significantly higher overall identification rate in comparison to the saponin method without that step for both genus (87.6% [85/97] vs. 70.1% [68/97], p = 0.0029) and species level (70.1% [68/97] vs. 46.4% [45/97], p = 0.0008). Identification rates of Gram-negative bacteria showed a higher identification rate, however, not statistically significant with additional Zybio Kit protocol step on both genus (85.4% [41/48] vs. 81.3% [39/48], p = 0.5858) and species level (77.1% [37/48] vs. 75% [36/48], p = 0.8120). Zybio Kit could offer an advantage in species-level identification, particularly for Gram-positive bacteria. The inclusion of on-plate formic acid extraction in the saponin method notably enhanced identification at both genus and species levels for Gram-positive bacteria. The extended protocol provided by the Zybio Kit could potentially offer an advantage in the identification of Gram-negative bacteria at both genus and species levels. Enhancements to the Zybio EXS2600 MALDI-TOF instrument software database are necessary.

High hemolytic activity of the Staphylococcus aureus spa t1081 among clonal complex 45 in Taiwan.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) sequence type (ST) 45 was first reported in Taiwan in 2006. Since then, the prevalence of ST45 MRSA in clinical isolates has increased. This study was carried out to understand the changes in the proportions, evolutionary relationships, and infection advantages of ST45 and its related clones. MATERIALS AND METHODS: S. aureus including MRSA and MSSA (methicillin-sensitive S. aureus), and clonal complex (CC) 45 blood isolates were collected in 2000, 2005, and from January 2010 to August 2014. Molecular typing, multiple-locus variable-number tandem repeat analysis (MLVA) and single nucleotide polymorphism (SNP)-based phylogenetic analysis were performed. Fitness and virulence analyses were used to understand the infection advantages of the isolates. RESULTS: Among the 67 CC45 isolates, only MSSA ST508 isolates were found in 2000 and 2005. Since 2010, the prevalence of MRSA has increased, t1081/ST45 has become dominant, and MRSA ST508 has been found. Phylogenetic analysis indicated that most of the ST45 isolates were located in a cluster distinct from those of ST508 and ST929. However, the t026 isolates clustered with the ST508 isolates rather than with the other ST45 isolates. Moreover, fitness and virulence analyses revealed that the t1081 isolates had higher hemolytic activity than the t026 and ST508 isolates did. CONCLUSION: Our findings indicated that the increased prevalence of ST45 MRSA isolates from blood cultures in Taiwan was due to the t1081 isolates, and their high hemolytic activity may provide an infection advantage.

Significance of blood culture testing after pancreatoduodenectomy.

Aim: The aim of this study was to clarify the significance of blood culture testing in the postoperative period of pancreatoduodectomy (PD), a highly invasive surgery. Methods: Rates of blood culture sampling and positivity were investigated for febrile episodes (FEs) in patients who underwent PD (2016-2021). FEs were defined as body temperature of 38.0°C or higher occurring on or after the 4th postoperative day. Fever origin was diagnosed retrospectively, and FEs were classified as pancreatic fistula (PF)-related or PF-unrelated FEs. Factors correlated with blood culture positivity were explored. Results: Among 339 patients who underwent PD, 99 experienced 202 FEs. Blood culture testing was performed on 160 FEs occurring in 89 patients. The sampling and positivity rates were 79.2% and 17.5%, respectively, per episode and 89.9% and 28.1%, respectively, per patient. Thirty-six FEs were classified as PF-related and 124 were classified as PF-unrelated FEs. The blood culture positivity rate was significantly lower in PF-related vs. PF-unrelated FEs (1/36 vs. 27/124, respectively, p = 0.006). The blood culture positivity rate was significantly higher in patients with cholangitis, catheter-related blood stream infection, and urinary tract infection than PF-related FEs. Multivariate analysis showed that blood culture positivity was negatively associated with PF-related FEs and positively associated with accompanying symptoms of shivering, Pitt Bacteremia Score, and preoperative biliary drainage. Conclusions: Patients who underwent PD showed relatively high blood culture positivity rates. Based on these results, it may be possible to distinguish PF-related and -unrelated FEs.

Role of neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio in diagnosing neonatal sepsis.

Clinical manifestations of neonatal sepsis are often unspecified. Therefore, sepsis biomarkers could be used to support diagnosis while waiting for blood culture results, such as the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR). The aim of this study was to evaluate the role of NLR and PLR as diagnostic markers in neonatal sepsis. A cross-sectional study was conducted at Haji Adam Malik General Hospital, Medan, Indonesia, from April to October 2019. This study included neonates aged less than 28 days, diagnosed with suspected sepsis, and had no previous history of antibiotics administration. Patients underwent clinical assessment, laboratory examination, and blood culture. Patients were grouped into sepsis and non-sepsis based on the blood culture results. The median hematological examination and the range of NLR and PLR in both the sepsis and non-sepsis groups were subjected to analysis using the Mann-Whitney U test to assess differences. NLR and PLR optimal cut-off values were determined using a receiver operator curve (ROC) with a confidence interval of 95%. A total of 137 neonates were enrolled, of which 49 were classified as sepsis and 89 as non-sepsis based on blood culture results. The optimal cutoff values for NLR and PLR were 2.75 and 11.73. Using those cutoff values, NLR and PLR could predict neonatal sepsis with sensitivities of 52.1% and 47.9%, specificities of 50.6% and 47.2%, area under the curve (AUC) of 0.46 and 0.47, with p=0.525 and p=0.662, respectively. Further investigation is warranted to refine the NLR and PLR utility and enhance diagnostic accuracy in clinical practices.

Prognostic and diagnostic utility of pancreatic stone protein in pediatric sepsis and mortality.

Background/aim: Early detection and prognosis of sepsis in critically ill children is crucial. The aim of this research was to investigate the prognostic ability of pancreatic stone protein (PSP) in validating sepsis and predicting mortality in a prospective observational study. Materials and methods: In a single-center study, pediatric intensive care unit patients were divided into cohorts of confirmed and suspected sepsis, as well as survivors and nonsurvivors. Patients with positive blood culture growth were considered to have confirmed sepsis, while their negative counterparts were considered to have suspected sepsis. Comparisons were made between complete blood counts, laboratory parameters, mortality indices, and C-reactive protein (CRP), procalcitonin (PCT), and PSP levels. The correlations between PSP and alternative inflammatory markers and mortality indices were then analyzed. The diagnostic and prognostic applicability of PSP for sepsis confirmation and mortality prediction was assessed using receiver operating characteristic curve analysis. Results: PSP levels were significantly elevated in patients with confirmed sepsis and within the nonsurvivor segment. In confirming sepsis and predicting mortality, PSP outperformed CRP and PCT in terms of sensitivity. It had sensitivity of 95% in diagnosing sepsis at a cut-off level of 50 ng/L, with an area under the curve (AUC) of 0.67 (95% CI: 0.52-0.81), and sensitivity of 92% in predicting mortality, with an AUC of 0.71 (95% CI: 0.56-0.83). In addition, PSP showed significant correlations with CRP, PCT, and mortality scores. Conclusion: PSP is emerging as a highly sensitive marker for confirming sepsis and predicting mortality in critically ill pediatric patients. Incorporating the PSP biomarker into routine clinical practice could potentially improve the management of pediatric sepsis.

Validity of reducing blood culture incubation time for the BD BACTEC FX blood culture system considering microbiological and clinical aspects.

INTRODUCTION: A blood culture (BC) test is vital for diagnosing bacteremia in clinical practice. Although incubation time varies among automated BC systems, 4-5 days is deemed to be sufficient time for the BD BACTEC FX blood culture system. This study compared the clinical and microbiological characteristics of true-positive BC samples on day 5 with those within 4 days to reduce missed true bacteremia cases. METHODS: We conducted a retrospective study of blood cultures from hospitalized patients between April 2020 and April 2023 at a tertiary care hospital in Japan. RESULTS: In total, 12,342 BC sets were collected from 6,567 patients. Gram-positive bacilli other than Bacillus spp. and Corynebacterium spp., non-albicans Candida, and yeasts other than Candida spp. were detected more frequently in BC-positive patients on day 5 than in those within 4 days. The gastrointestinal tract was the portal of entry more frequently on day 5 than within 4 days (25 % vs. 4 %, p = 0.006). CONCLUSION: A 4-day incubation period is sufficient for the BD BACTEC FX blood culture system under routine conditions. However, a 5-day incubation period may be warranted when low pathogenicity is suspected or the gastrointestinal tract is suspected as the portal of entry.

Effectiveness of A Nurse-Led Multimodal Intervention in Preventing Blood Culture Contamination: A Before-and-After Study.

Blood culture is crucial for accurate and timely bacteremia diagnosis and guide antibiotic therapy. However, during culture sampling, contamination can occur, resulting in misdiagnosis, unnecessary antibiotic exposure, and prolonged hospitalization. This before-and-after intervention study aimed to evaluate the effectiveness of a multimodal intervention in preventing blood culture contamination. The study was conducted in a 170-bed hospital in Portugal and included a total of 23,566 blood cultures. Contamination rates were assessed in two phases: Phase 1 (before intervention, month 0) included 10,928 cultures, and Phase 2 (after intervention, month 6) included 12,638 cultures. During the study period, a multimodal intervention targeting the nursing staff was implemented, consisting of training actions, guideline updates, regular data monitoring and feedback, and introduction of a blood culture pack. Following the intervention, blood culture contamination decreased from 6.8% (Phase 1) to 3.9% (Phase 2). A comparative analysis revealed that the risk of contamination before the intervention was nearly four times higher in first culture, OR = 3.97 (CI 2.86-5.49). Our findings suggest that the multimodal intervention enhanced nurses' adherence to recommended practices, resulting in a reduced risk of blood culture contamination, earlier identification of infectious agents, and improved accuracy of antibiotic therapy.

Whipple's Disease Endocarditis Following Immunomodulatory Treatment for Arthritis: A Case Report and Screening Recommendation.

Whipple's disease (WD) is a rare systemic disorder affecting various organ systems, including the gastrointestinal, cardiovascular, and joint systems. This report discusses a case of WD endocarditis likely associated with tocilizumab (TCZ), an immunomodulator used to treat refractory seronegative arthritis, in a patient with coronary artery disease and rheumatoid arthritis. The diagnosis was confirmed through laboratory studies, imaging, and esophagogastroduodenoscopy with biopsies. WD is increasingly recognized as a potential etiology of seronegative arthritis, with joint pain often preceding gastrointestinal symptoms. Immunomodulatory agents such as TCZ, while effective for rheumatoid arthritis, may exacerbate underlying WD, potentially leading to severe complications such as endocarditis. This case reveals the importance of considering WD in patients with refractory arthritis and the necessity of thorough diagnostic evaluation before initiating immunomodulatory therapy. Epidemiological studies indicate a higher prevalence of WD in certain demographics, highlighting the need for targeted screening with noninvasive screening methodologies, such as stool and saliva polymerase chain reaction testing.

Synovial fluid analysis in healthy green turtles Chelonia mydas in Taiwan.

Septic arthritis is a frustrating disease in sea turtle rehabilitation because of its unclear pathogenesis, delayed onset during rehabilitation, long-term treatment requirements, and potentially poor prognosis. Radiography, blood cultures, and arthrocentesis have been used as diagnostic tools for suspected cases. However, there is currently a lack of data on the characteristics of synovial fluid in healthy sea turtles. To establish reference data for synovial fluid in sea turtles, we enrolled 14 green turtles Chelonia mydas rescued between 2019 and 2022 from 3 facilities using the following inclusion criteria: normal attitude and appetite, normal motor functions of the 4 limbs, no joint swelling, and no ongoing use of antibiotics for at least 1 mo. Bacterial cultures of blood and synovial fluid from the shoulder joints of these turtles were obtained and a qualitative analysis of the synovial fluid was performed. The results revealed bacterial culture-negative blood and synovial fluids at 37°C. Most characteristics of normal synovial fluid in green turtles, such as being transparent, colorless, and able to create a strand of over 2.5 cm by being pulled with a needle in viscosity trials, as well as the cytology of the normal synovial fluids being dominated by histiocytes and synovial lining cells, lymphocytes, and occasionally a few heterophils or erythrocytes were similar to those in mammals. This study provides information on the normal synovial fluid characteristics of green turtles in Taiwan, which may be beneficial for the diagnosis of joint diseases in sea turtles.

Pseudo-outbreak of Bacillaceae species associated with poor compliance with blood culture collection recommendations.

PURPOSE: This study describes a pseudo-outbreak of Bacillaceae spp. bloodstream infections that spanned five months starting in May 2023 and the infection prevention measures implemented to control it. METHODS: This retrospective study was conducted at a tertiary infectious disease hospital in Bucharest, Romania. An observational audit of the blood culture collection practice in our hospital was performed, and the materials used during blood culture collection were sampled. Bacterial colonies were identified using MALDI Biotyper. The Bacillaceae blood culture positivity rates in the previous four years were compared using the Kruskal‒Wallis rank test. RESULTS: Bacillaceae spp.-positive blood cultures were recovered from 60 patients over a five-month period. In the case of 58 patients, Bacillaceae spp.-positive blood cultures were considered contaminated. Two patients were treated for Bacillus spp. bacteraemia. The audit revealed significant variation during the preparation of the venipuncture site step and the use of nonsterile medical cotton wool. Medical cotton wool contaminated with species of Bacillaceae was found in 10 out of 12 wards. The control measures included repeated training on the blood culture collection procedure and the removal of Bacillaceae spp.-contaminated cotton wool. CONCLUSIONS: The pseudo-outbreak was caused by the unjustified use of medical cotton wool for disinfection of the skin and blood culture bottle septums. The investigation of this pseudo-outbreak highlighted a gap in blood culture collection practices at our facility and thus allowed for its improvement.

Diagnosis and Management of Neonatal Bacterial Sepsis: Current Challenges and Future Perspectives.

Sepsis remains the second cause of death among neonates after the pathological consequences of extreme prematurity. In this review we summarized knowledge about pathogens causing early-onset sepsis (EOS) and late-onset sepsis (LOS), the role of perinatal risk factors in determining the EOS risk, and the tools used to reduce unnecessary antibiotics. New molecular assays could improve the accuracy of standard blood cultures, providing the opportunity for a quick and sensitive tool. Different sepsis criteria and biomarkers are available to date, but further research is needed to guide the use of antibiotics according to these tools. Beyond the historical antibiotic regimens in EOS and LOS episodes, antibiotics should be based on the local flora and promptly modulated if specific pathogens are identified. The possibility of an antibiotic lock therapy for central venous catheters should be further investigated. In the near future, artificial intelligence could help us to personalize treatments and reduce the increasing trend of multidrug-resistant bacteria.

Simulation to optimize the laboratory diagnosis of bacteremia.

Blood cultures are central to the management of patients with sepsis and bloodstream infection. Clinical decisions depend on the timely availability of laboratory information, which, in turn, depends on the optimal laboratory processing of specimens. Discrete event simulation (DES) offers insights into where optimization efforts can be targeted. Here, we generate a detailed process map of blood culture processing within a laboratory and use it to build a simulator. Direct observation of laboratory staff processing blood cultures was used to generate a flowchart of the blood culture laboratory pathway. Retrospective routinely collected data were combined with direct observations to generate probability distributions over the time taken for each event. These data were used to inform the DES model. A sensitivity analysis explored the impact of staff availability on turnaround times. A flowchart of the blood culture pathway was constructed, spanning labeling, incubation, organism identification, and antimicrobial susceptibility testing. Thirteen processes in earlier stages of the pathway, not otherwise captured by routinely collected data, were timed using direct observations. Observations revealed that specimen processing is predominantly batched. Another eight processes were timed using retrospective data. A simulator was built using DES. Sensitivity analysis revealed that specimen progression through the simulation was especially sensitive to laboratory technician availability. Gram stain reporting time was also sensitive to laboratory scientist availability. Our laboratory simulation model has wide-ranging applications for the optimization of laboratory processes and effective implementation of the changes required for faster and more accurate results. IMPORTANCE: Optimization of laboratory pathways and resource availability has a direct impact on the clinical management of patients with bloodstream infection. This research offers an insight into the laboratory processing of blood cultures at a system level and allows clinical microbiology laboratories to explore the impact of changes to processes and resources.

Evaluation of the Reveal® AST (SPECIFIC) for Antimicrobial Susceptibility Testing from Positive Blood Culture Spiked with Carbapenem-Resistant Isolates.

As bloodstream infections and associated septic shock are common causes of mortality in hospitals, rapid antibiotic susceptibility testing (AST) performed directly on positive blood cultures is needed to implement an efficient therapy in clinical settings. We evaluated the Reveal® rapid AST system on a collection of 197 fully characterized carbapenem-resistant Enterobacterales, including 177 carbapenemase producers (CPE) spiked in blood culture bottles. The clinical categorization based on the Minimal Inhibitory Concentration (MIC) determination of eighteen antimicrobial molecules was compared to the clinical categorization based on the disk diffusion assay as a reference. The Reveal AST system provided results within a mean time to result of 5 h. Overall, the categorical agreement (CA) between the two techniques was 94.1%. The rates of very major errors (VMEs), major errors (MEs) and minor errors (mEs) were 3.8%, 3.7% and 5.6%, respectively. Imipenem was the antimicrobial with the lowest CA rate (78.7%), with rates of 15% VMEs and 10.7% MEs, but the performances were better when considering only the non-CPE category (CA of 89%). On this resistant collection of Enterobacterales with numerous acquired ß-lactamases, the Specific Reveal assay proved to be useful for a rapid determination of AST compatible with a quick adaptation of the patient's antimicrobial treatment.

Every Crisis Is an Opportunity: Advancing Blood Culture Stewardship During a Blood Culture Bottle Shortage.

The current manufacturing disruption of BACTEC blood culture bottles has drawn attention to diagnostic stewardship around blood culture utilization. In this perspective, we offer strategies for implementing blood culture stewardship using a graded approach based on a hospital's blood culture bottle supply. These strategies should inform plans to mitigate the impact of the shortage on patient care and reinforce fundamental principles of blood culture stewardship.