A Case of Bacteremia Caused by Raoultella planticola Direct Identification from Blood Culture by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry.

Background: Raoultella planticola is an uncommon gram-negative organism found in the environment. Patients and Methods: The patient, an 81-year-old female who had undergone total cystectomy and bilateral ureteral stoma surgery, presented to the hospital with a fever. It was determined that Raoultella planticola was responsible for the bacteremia. Results: Rapid identification of bacteria using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) in blood culture samples and appropriate antibacterial treatment was begun and the patient was discharged three days later. Conclusions: This case emphasizes the presence of a rare pathogen as the cause of bacteremia and underscores the importance of utilizing rapid methods for bacterial identification to establish an accurate diagnosis.

Detection of KPC directly from positive blood cultures by MALDI-TOF: From research to the clinical microbiology laboratory routine.

Bloodstream infections (BSI) caused by carbapenem-resistant Gram-negative bacilli (CR-GNB) are a subject of major clinical concern, mainly those associated with carbapenemase-producing isolates. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been proposed to detect specific ß-lactamases, including KPC. We aimed to detect KPC enzyme directly from positive blood cultures using MALDI-TOF MS. Overall, 146 clinical Gram-negative bacilli (46 CR-GNB) recovered from consecutive blood cultures were evaluated. Proteins were extracted using formic acid, isopropyl alcohol, and water and spotted onto a steel target plate using the double-layer sinapinic acid method. The relative ions intensity ≥120 arbitrary units (a.u.) of a peak close to 28,700 m/z indicated the presence of KPC. The results were compared to HRM-qPCR methodology. This specific peak was observed in 11/14 blood bottles with blaKPC positive isolates (78.6% sensitivity), with 3 false-positive results (97.7% specificity). Analysis from colonies reached identical sensitivity (78.6%), but higher specificity (100%). The detection of KPC peaks directly from positive blood cultures using MALDI-TOF MS is feasible and rapid. It's excellent specificity indicates that positive results are consistently associated with the presence of a KPC producer in positive blood culture.

Evaluation of an automated rapid phenotypic antimicrobial susceptibility testing (ASTar, Q-linea AB) applied directly on blood cultures bottles positive for Gram-negative pathogens.

We evaluated the performance of a new rapid phenotypic antimicrobial susceptibility test (ASTar; Q-linea AB) on Gram-negative bacilli, directly from positive blood cultures bottles. MIC values obtained by the routine reference method (Microscan, Beckman Coulter) were compared to the ones provided by the tested method (ASTar). ASTar demonstrated an overall essential agreement of 98% and a category agreement of 96.1%. The overall rate of major errors and very major errors was 2.5% and 3.3%, respectively. ASTar can represent a rapid, simple, and reliable method to speed up information about antimicrobial susceptibility of Gram-negative pathogens from positive blood culture bottles.

Hemocultivos contaminados: bundle para lograr proporciones aceptables / Blood cultures contaminated: bundle to achieve acceptable proportions

Introducción. El problema de la contaminación de los hemocultivos es muy frecuente en establecimientos de atención hospitalaria, da lugar a la administración de antibióticos innecesarios y prolonga la hospitalización. Objetivo principal. Aplicar un bundle para reducir la proporción de contaminación de hemocultivos. Objetivo secundario. Realizar una encuesta anónima para detectar oportunidades de mejora en la técnica de extracción de hemocultivos. Metodología. Diseño del estudio: Estudio cuasi experimental que evaluó la proporción de contaminación de hemocultivos antes y después de implementar un bundle propio. Se determinó la proporción basal de contaminación de hemocultivos (ene-jul 2022), se realizó la intervención (agosto 2022) y se estableció la proporción de contaminación post intervención (sep.-abril 2023). Intervención: Se analizó la estructura, procedimiento y conocimiento del personal mediante una encuesta propia para detectar áreas de mejora. Se capacitó, a los técnicos de laboratorio, sobre el procedimiento de la toma de muestra mediante una simulación utilizando un brazo artificial. Se diseñó un bundle de seis medidas, se adaptó el procedimiento de toma de hemocultivo y se capacitó al personal. Análisis estadístico. Se analizó la proporción de hemocultivos contaminados entre los periodos pre y post utilizando Chi2 y la relación entre la proporción del periodo pre y post vs la literatura (3.00% contaminación aceptable) utilizando test Z para una proporción. Se consideró un p<0.05 como estadísticamente significativa. Se utilizo el software Stata 8. Resultados. Durante el estudio se analizaron un total de 3,965 hemocultivos. De estos, 1,978 corresponden al periodo pre-intervención y 1,987 corresponden al periodo post intervención. Durante la pre-intervención se detectaron 61 hemocultivos contaminados (3.08% vs 3.00% bibliografía, p:0.5866) mientras que en la etapa post intervención fue de 30 hemocultivos contaminados (1.51% vs 3.00% bibliografía, p:0.0000). La proporción de hemocultivos contaminados se redujo a la mitad, 3.08% vs 1.51%, p: 0.001. Se realizó una encuesta anónima pre y post intervención logrando mejoras en la técnica de toma de hemocultivos. Conclusión. La implementación del bundle propio para la extracción de hemocultivos, permitió reducir la proporción de contaminación a la mitad. El análisis de la encuesta nos permitió identificar oportunidades de mejora en la técnica de recolección de muestra de hemocultivos

Introduction: Contamination of blood cultures is very common in hospital care settings and results in the administration of unnecessary antibiotics and prolongs hospitalization. Main goal: Apply a bundle to reduce the rate of contamination of blood cultures. Secondary objective: Conduct an anonymous survey to detect opportunities for improvement in the blood culture extraction technique. Methodology: Study design: Quasi-experimental study that evaluated the proportion of blood culture contamination before and after implementing its own bundle. The baseline proportion of blood culture contamination was determined (Jan-July 2022), the intervention was performed (August 2022) and the post-intervention contamination proportion was established (September-April 2023). Intervention: The structure, procedure and knowledge of the staff was analyzed through an own survey to detect areas for improvement. Laboratory technicians were trained on the sample collection procedure through a simulation using an artificial arm. A bundle of six measures was designed: (hand hygiene with alcohol gel, use of common gloves and sterile gloves during extraction, antisepsis with alcoholic chlorhexidine gluconate, marking of the blood culture bottle up to the filling level, disinfection of the bottle cap). blood culture bottle with 70% alcohol, safety-lok kit with vacuum extraction system). The procedure was adapted and staff trained. Statistic analysis: The proportion of contaminated blood cultures between the pre and post periods was analyzed using Chi2 and the relationship between the proportion of the pre and post period vs the literature (3.00% acceptable contamination) using Z test for a proportion. P<0.05 was considered statistically significant. Stata 8 software was used.Results: A total of 3,965 blood cultures were analyzed during the study. Of these, 1,978 correspond to the pre-intervention period and 1,987 correspond to the post-intervention period. During the pre-intervention, 61 contaminated blood cultures were detected (3.08%) while in the post-intervention stage there were 30 contaminated blood cultures (1.51%). The proportion of contaminated blood cultures was reduced by half, 3.08% vs 1.51%, p: 0.001. An anonymous survey was carried out pre and post intervention, achieving improvements in the technique of taking blood cultures. Conclusion: The implementation of the own bundle for the extraction of blood cultures allowed the contamination rate to be reduced by ha

Pitfalls of a Multiplex PCR Panel for Identification of Bloodstream Pathogens.

BACKGROUND: We evaluated the diagnostic performance of the FilmArray Blood Culture Identification Panel (BCID; bioMerieux) for the detection of bloodstream pathogens. METHODS: From May to August 2022, up to 67 samples from positive blood cultures previously processed with BACTEC FX (BD) were collected and submitted to the BCID panel. BCID panel results were compared with traditional culture results. RESULTS: We tested 67 positive blood culture samples; 13 samples were from pediatric bottles of BACTEC Peds Plus/F media (BD). The overall sensitivity of the BCID panel was 89.9% (62/69; 95% CI, 80.2 - 95.3%). For blood-stream pathogens targeted by the BCID panel, sensitivity was 98.4% (62/63; 95% CI, 90.7 - > 99.9%). Interestingly, Proteus species were additionally detected in 6 samples from pediatric blood culture bottles. CONCLUSIONS: BCID demonstrated high clinical sensitivity for target pathogens, but positive findings for unexpected multiple targets or Proteus species require cautious interpretation to avoid false positives.

Evaluation of three protocols for direct susceptibility testing for Gram-negative rods from flagged positive blood culture bottles.

Bloodstream infections are associated with high mortality, which can be reduced by targeted antibiotic therapy in the early stages of infection. Direct antibiotic susceptibility testing (AST) from flagged positive blood cultures may facilitate the administration of early effective antimicrobials much before the routine AST. This study aimed to evaluate three different direct AST protocols for Gram-negative rods from flagged positive blood culture broths. Blood culture broths showing Gram-negative rods only were subjected to direct AST by Clinical and Laboratory Standards Institute-recommended direct disk diffusion (protocol A). Additionally, automated AST (protocol B) and Kirby-Bauer disk diffusion (protocol C) were performed with standard inoculum prepared from bacterial pellets obtained by centrifuging blood culture broths in serum separator vials. For comparison, conventional AST of isolates from solid media subculture was also performed with Kirby-Bauer disk diffusion (reference standard) and the automated method. Overall, categorical agreements of protocols A, B, and C were 97.6%, 95.7%, and 95.9%, respectively. Among Enterobacterales, minor error, major error, and very major error rates of protocol B were 3.5%, 0.36%, and 0.43%, respectively, whereas minor error, major error, and very major error rates of protocol C were 3.4%, 0.72%, and 0.21%, respectively, and among non-fermenters, protocol B had a minor error rate of 6.5%, and protocol C had a minor error rate of 4.1% and major error rate of 1.9%. All three direct AST protocols demonstrated excellent categorical agreements with the reference method. Performance of protocols B and C between Enterobacterales and non-fermenters was not statistically different. IMPORTANCE: Bloodstream infections are associated with high mortality that can be reduced by targeted antibiotic therapy in the early stages of infection. Direct antibiotic susceptibility testing (AST) from flagged positive blood cultures may facilitate the administration of early effective antimicrobials much before the routine AST. Clinical and Laboratory Standards Institute-recommended direct AST can be performed with a limited number of antibiotic disks only. On the other hand, using an automated system for direct AST will not only allow effective laboratory workflow with reduced turnaround time but also provide the minimum inhibitory concentration values of tested antibiotics. However, using expensive automated systems for direct AST may not be feasible for resource-limited laboratories. Therefore, in this study, we aimed to evaluate the CLSI-recommended method and two other direct AST protocols (one with an automated system and the other with disk diffusion) for Gram-negative rods from flagged positive blood cultures.

Rapid diagnostic of multidrug-resistant sepsis pathogens directly from blood culture bottles using MALDI-TOF and the EUCAST RAST.

In this study, rapid diagnostic of multidrug-resistant (MDR) sepsis pathogens, directly from positive blood culture (BC) bottles, was evaluated by combining MALDI-TOF and the EUCAST Rapid Antimicrobial Susceptibility Testing (RAST). Carbapenemase production in Escherichia coli and Klebsiella pneumoniae isolates was also evaluated by RAST. From 171 positive BC bottles analyzed, 79 (46 %) MDR species, including E. coli (4/34, 12 %), K. pneumoniae (33/48, 69 %), Pseudomonas aeruginosa (12/12, 100 %), Acinetobacter baumannii (15/15, 100 %), and Staphylococcus aureus (14/37, 38 %) displaying resistance to beta-lactams, fluoroquinolones, aminoglycosides, and/or trimethoprim/sulphamethoxazole, were identified. In this regard, turnaround time of direct MALDI-TOF identification and RAST was < 7 h, which was significantly (p< 0.05) lower than our routine method. Carbapenemase detection by RAST displayed 100% sensitivity and 88.7 % specificity at 8 h. This protocol could offer advantages for the treatment and clinical outcomes of septic patients, improving the rapid diagnostic of sepsis by MDR pathogens.

Rapid identification,fluconazole and micafungin susceptibility testing of Candida species from blood culture by a short incubation method.

This study aimed to develop and validate a rapid method for identification by MALDI-TOF system and determination of the susceptibility to Fluconazole and Micafungin by broth microdilution among Candidaspecies causing bloodstream infections. Subcultures from blood culture bottles were incubated for 5 hours (+/- 1h) and used to perform the tests, so that the turnaround time of rapid identification and susceptibility profile was about 5 and 24 hours, respectively. The rapid identification showed agreement of 92.05 %. Regarding the rapid broth microdilution for Fluconazole and Micafungin, the agreement was 97.06 % (p<0.001) and 100 % (p<0.001), and the Kappa coefficient was 0.91 (p<0.001) and 1.0 (p<0.001), respectively. To conclude, both rapid methods showed to be reproducible, inexpensive, easy to perform and time-saving. Thus, these methodologies could be useful to guide and adjust empirical antifungal therapy.

Clinical utility of multiplex PCR in the detection of pathogens from sterile body fluids.

Rapid identification of pathogens in normally sterile body fluid (NSBF) is essential for appropriate patient management, specifically antimicrobial therapy. Limited sensitivity and increased time to detection of traditional culture prompted us to evaluate additional testing to contribute to the diagnosis of infection. The purpose of this study was to evaluate the GenMark Dx ePlex Blood Culture Identification (BCID) Panels on positive body fluids inoculated into blood culture bottles for the detection of microorganisms. A total of 88 positive body fluids from blood culture bottles were analyzed using a Gram-Positive, Gram-Negative, and/or Fungal pathogen BCID Panel based on the Gram stain result. Each result was compared to routine culture performed from the positive bottle. When using culture as a reference standard, we found the ePlex multiplex panel performed with a positive percent agreement of 96.5% and a negative percent agreement of 99.8%. The use of multiplex PCR may be a useful supplement to routine culture for NSBF in blood culture bottles. IMPORTANCE: The identification of pathogens in normally sterile body fluid (NSBF) is performed using routine culture, the current gold standard. Limitations of this method include sensitivity and increased turnaround times which could potentially delay vital patient care, especially antimicrobial therapy. Adaptations of NSBF in blood culture bottles prompted us to consider the utility of additional methods to bridge the gap in diagnostic challenges for these life-threatening infections. Multiplex molecular panels have been manufactured for use with multiple specimen types including blood, cerebral spinal fluid, stool, and respiratory. Therefore, the purpose of this study was to evaluate the off-label use of ePlex Blood Culture Identification Panels on positive body fluids grown in blood culture bottles for the detection of microorganisms for research purposes.

An emergency department intervention to improve earlier detection of community-onset bloodstream infection among hospitalized patients.

BACKGROUND: Blood cultures (BCs) are essential microbiologic tests, but blood culturing diagnostic stewardship is frequently poor. We aimed to study the process-related failures and to evaluate the effect of an emergency department (ED) intervention on BCs collection practices and yield. METHODS: We implemented an ED-quality improvement intervention including educational sessions, phlebotomists addition, promoting single-site strategy for BC-collection and preanalytical data feedback. BC-bottles collected, positive BCs, blood volumes and documentation of collection times were measured, before (December 2021-August 2022) and after (September 2022-July 2023) intervention. Results were corrected to hospitalizations admissions or days. We used interrupted-time series analyses for comparisons. RESULTS: A total of 64,295 BC bottles were evaluated, 26,261 before and 38,034 postintervention. The median ED-BCs collected per week increased from 88 to 105 BCs (P < .0001), resulting from increased early sampling (P = .0001). Solitary BCs decreased (95%-28%), documented times increased (2.8%-25%), and average blood volume increased (3 mL to 4.5 mL) postintervention. Community-onset Bloodstream infections (BSIs) increased (39.6-52 bottles/1,000 admissions, P = .0001), while Health care-associated BSIs decreased (39-27 bottles/10,000 days, P = .0042). Contamination rates did not change. CONCLUSIONS: An ED-focused intervention based on the education sessions and single-site strategy improved culturing stewardship and facilitated the early identification of BSI without an increase in contamination.

Rapid nanopore sequencing and predictive susceptibility testing of positive blood cultures from intensive care patients with sepsis.

We aimed to evaluate the performance of Oxford Nanopore Technologies (ONT) sequencing from positive blood culture (BC) broths for bacterial identification and antimicrobial susceptibility prediction. Patients with suspected sepsis in four intensive care units were prospectively enrolled. Human-depleted DNA was extracted from positive BC broths and sequenced using ONT (MinION). Species abundance was estimated using Kraken2, and a cloud-based system (AREScloud) provided in silico predictive antimicrobial susceptibility testing (AST) from assembled contigs. Results were compared to conventional identification and phenotypic AST. Species-level agreement between conventional methods and AST predicted from sequencing was 94.2% (49/52), increasing to 100% in monomicrobial infections. In 262 high-quality AREScloud AST predictions across 24 samples, categorical agreement (CA) was 89.3%, with major error (ME) and very major error (VME) rates of 10.5% and 12.1%, respectively. Over 90% CA was achieved for some taxa (e.g., Staphylococcus aureus) but was suboptimal for Pseudomonas aeruginosa. In 470 AST predictions across 42 samples, with both high quality and exploratory-only predictions, overall CA, ME, and VME rates were 87.7%, 8.3%, and 28.4%. VME rates were inflated by false susceptibility calls in a small number of species/antibiotic combinations with few representative resistant isolates. Time to reporting from sequencing could be achieved within 8-16 h from BC positivity. Direct sequencing from positive BC broths is feasible and can provide accurate predictive AST for some species. ONT-based approaches may be faster but significant improvements in accuracy are required before it can be considered for clinical use.IMPORTANCESepsis and bloodstream infections carry a high risk of morbidity and mortality. Rapid identification and susceptibility prediction of causative pathogens, using Nanopore sequencing direct from blood cultures, may offer clinical benefit. We assessed this approach in comparison to conventional phenotypic methods and determined the accuracy of species identification and susceptibility prediction from genomic data. While this workflow holds promise, and performed well for some common bacterial species, improvements in sequencing accuracy and more robust predictive algorithms across a diverse range of organisms are required before this can be considered for clinical use. However, results could be achieved in timeframes that are faster than conventional phenotypic methods.

[Does a rapid antibiotic susceptibility test optimize antibiotic therapy of patients with bacteremia ?] / Un antibiogramme rapide optimise-t-il la prise en charge thérapeutique des patients présentant une bactériémie ?

BACKGROUND: We evaluated the contribution of a rapid antibiotic susceptibility test performed directly from a positive blood culture (PBC), the dRAST™, in the management of patients with bacteremia. METHODS: We retrospectively compared the time from sampling to availability of antibiotic susceptibility test (AST) results («time-to-result¼, TTR) between dRAST™ and classic AST (Vitek®2), in 150 patients with bacteremia. The antibiotic treatment of these 150 patients was classified into three categories (optimal, suboptimal, ineffective) according to the time of availability of AST results. RESULTS: Adaptation of antibiotic treatment to optimal therapy following AST results occurred in 46/100 (46 %) of Gram-negative PBC and in 4/50 (2 %) of Gram-positive HP. TTR was significantly lower with dRAST™ compared with classic AST (29:35 (± 08:48) hours versus 50:55 (± 12:45) hours, p < 0.001). CONCLUSION: For patients with bacteremia requiring adjustment of empirical antibiotic therapy based on AST, dRAST™ could allow a faster administration of optimal therapy.

CONTEXTE: Nous avons évalué la contribution d'un antibiogramme rapide réalisé directement à partir d'une hémoculture positive (HP), le dRAST™, dans la prise en charge des patients présentant une bactériémie. Méthodes: Nous avons comparé, rétrospectivement, le délai entre le prélèvement et la disponibilité des résultats d'antibiogramme («temps-pour-résultats¼, TPR) entre le dRAST™ et l'antibiogramme classique (Vitek®2), auprès de 150 patients présentant une bactériémie. Les antibiothérapies de ces 150 patients ont été classés en trois catégories (optimale, suboptimale, inefficace) en fonction du moment d'obtention des résultats de l'antibiogramme. Résultats : L'adaptation du traitement antibiotique en thérapie optimale suite au résultat de l'antibiogramme est survenue chez 46/100 (46 %) des HP à Gram négatif et chez 4/50 (2 %) des HP à Gram positif. Le TPR était significativement plus faible avec le dRAST™ par rapport à l'antibiogramme classique (29:35 (± 08:48) heures versus 50:55 (± 12:45) heures, p < 0,001). CONCLUSION: Pour les patients avec bactériémie nécessitant une adaptation de l'antibiothérapie empirique basée sur l'antibiogramme, le dRAST™ permettrait une administration plus rapide du traitement optimal.

Benchmarking blood culture quality in the emergency department: Contamination, single sets and positivity.

OBJECTIVE: To benchmark blood culture (BC) quality in an Australian ED, explore groups at risk of suboptimal BC collection, and identify potential areas for improvement. METHODS: This retrospective observational study was undertaken to benchmark quality of BCs in a tertiary adult ED in terms of number of BC sets per patient and proportion of patients with false positive (contaminated) BC results. RESULTS: A single BC set was taken for 55% of patients, with lower acuity patients being more likely to have a single BC set taken. BC false positives occurred in 3.4% of presentations, with higher frequency in some critically unwell patient groups. The true positive BC rate was 10.9%, with pathogens most frequently isolated in older patients, those with a haematological condition or genitourinary source, and those admitted to inpatient wards. Hospital length of stay did not differ between patients with negative and patients with false positive BCs. CONCLUSIONS: BC quality standards in the ED such as false positive rate <3% and single culture rate <20% are required to facilitate benchmarking and prospective quality improvement. The sensitivity and specificity of this common and critical test can be improved. Patient subgroups associated with poor-quality BC collection can be identified and should be a focus of future work.

Clinical impacts of the rapid diagnostic method on positive blood cultures.

OBJECTIVE: This study aimed to evaluate the impact of short-term incubation (STI) protocol on clinical outcomes of bloodstream infection (BSI) patients. METHODS: A total of 1363 positive blood culture records from January 2019 to December 2021 were included. The main clinical outcomes included pathogen identification turnaround time (TAT), antimicrobial susceptibility testing (AST) TAT, and length of total hospital stay. RESULTS: The TAT of pathogen identification and AST significantly decreased after implementing the STI protocol (2.2 vs 1.4 days and 3.4 vs 2.5 days, respectively, with P < .001 for both). Moreover, for patients with Gram-negative bacteria (GNB)-infected BSIs, the length of total hospital stay decreased from 31.9 days to 27.1 days, indicating that these patients could be discharged 5 days earlier after implementing the STI protocol (P < .01). CONCLUSION: The protocol led to a significant reduction in TAT and improved clinical outcomes, particularly for GNB organisms. The findings suggest that the STI protocol can improve patient outcomes and hospital resource utilization in the management of BSIs.

Comparison of new and old BacT/ALERT aerobic bottles for detection of Candida species.

PURPOSE: A new version of aerobic blood culture media has been developed for the BacT/ALERT (bioMérieux) blood culture system. We evaluated the time to detection and yeast cell counts in positive blood cultures for each Candida spp. according to changes in media. METHODS: Isolates from defibrinated horse blood were inoculated into three types of bottles: the old version of aerobic bottle, new version of aerobic bottle, and anaerobic bottle. All bottles were incubated in the BacT/ALERT Virtuo blood culture system. The time to detection was monitored for each bottle, and yeast cell counts were performed immediately after testing positive, determined via the plate count method. Clinical retrospective data of the candidemia samples before and after aerobic bottle change also were analyzed. RESULTS: The median time to detection was 52.47 hours in the old aerobic bottles versus 19.92 hours in the new aerobic bottles (P < 0.001) for Candida glabrata, and standard and clinical strains showed similar results. C. albicans (27.6 to 24.95 hours) and C. guilliermondii (28.92 to 26.9 hours) had shorter time to detection. However, C. auris (25.43 to 28.25 hours) had a longer time to detection in the new aerobic bottle. The retrospective clinical analysis showed a significant decrease in time to detection (45.0 to 19.4 hours) for C. glabrata, which is consistent with our simulated study result for C. glabrata. As a result of analysis including all blood specimens, C. tropicalis showed a significant delay in time to detection in new aerobic bottles. In an analysis limited to peripheral blood specimens, the time to detection of C. parapsilosis was longer in new aerobic bottles than in old aerobic bottles. CONCLUSION: Most Candida species did not show remarkable TTD differences, but TTD of C. glabrata was markedly reduced in the New FA Plus bottle. The reduction of time to detection enables faster detection and therapeutic approach for C. glabrata infections.

Blood culture identification (BCID) performance in polymicrobial bacteremia.

The rapid multiplex PCR (rmPCR)-based FilmArray® blood culture identification (BCID) assay reduces time from positive blood culture to organism identification. Polymicrobial bacteremia (PMB) is a known area of reduced diagnostic fidelity for BCID and remains incompletely characterized. All cases of clinically confirmed PMB at a large academic single center from a 23-month period were evaluated in a retrospective cohort analysis. A total of 207 samples were identified and studied. Overall, 49.3% (N = 102) of polymicrobial cultures were incompletely identified by FilmArray® result. There were no significant between-group differences in comorbidity status, length of stay, mortality, or source between patients with PMB who had complete versus incomplete BCID identification. Our results suggest that rmPCR-based assays frequently miss organisms in PMB and should be interpreted accordingly.

Optimizing Blood Culture Collection Volumes.

ABSTRACT: Infection in an immunocompromised person can be a life-threatening emergency. Collection of blood culture specimens is an important method for detecting organisms when infection is suspected. One aspect of proper blood culture collection is obtaining an accurate blood volume in the sample in accordance with the blood culture bottle manufacturer's recommendation. Underfilling the culture bottle can lead to false-negative results, while overfilling it can lead to false-positive results. At our institution, the Department of Laboratory Medicine (DLM) routinely monitors blood culture bottle volumes and notifies the nursing department of underfill/overfill events, which the department then reviews. Over several years, the DLM and the nursing department noted an increase in these events. A clinical nurse specialist and three staff nurses in the oncology/critical care services area partnered with the DLM to determine why. Upon investigation, two key issues-imprecise weighing of bottles and staff misunderstanding of the proper blood culture collection technique-were discovered. In response, the nursing standard of practice and guidance on the DLM webpage were updated and nursing education was performed. As a result, underfill/overfill events decreased by 71% in a little over a year.

Rapid phenotypic antimicrobial susceptibility testing of Gram-negative rods directly from positive blood cultures using the novel Q-linea ASTar system.

Adequate and timely antibiotic therapy is crucial for the treatment of sepsis. Innovative systems, like the Q-linea ASTar, have been developed to perform rapid antimicrobial susceptibility testing (AST) directly from positive blood cultures (BCs). We conducted a prospective study to evaluate ASTar under real-life conditions with a focus on time-to-result and impact on antimicrobial therapy. Over 2 months, all positive BCs that showed Gram-negative rods upon microscopy were tested with the ASTar and our standard procedure (VITEK 2 from short-term culture). Additionally, we included multidrug-resistant Gram-negative bacteria from our archive. Both methods were compared to broth microdilution. In total, 78 bacterial strains (51 prospective and 27 archived) were tested. ASTar covered 94% of the species encountered. The categorical and essential agreement was 95.6% and 90.7%, respectively. ASTar caused 2.4% minor, 2.0% major, and 2.4% very major errors. The categorical agreement was similar to standard procedure. The average time between BC sampling and the availability of the antibiogram for the attending physician was 28 h 49 min for ASTar and 44 h 18 min for standard procedure. ASTar correctly identified all patients who required an escalation of antimicrobial therapy and 75% of those who were eligible for de-escalation. In conclusion, ASTar provided reliable AST results and significantly shortened the time to obtain an antibiogram. However, the percentage of patients that will profit from ASTar in a low-resistance setting is limited, and it is currently unclear if a change of therapy 29 h after BC sampling will have a significant impact on the patient's prognosis.