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Introduction: Pneumococcal bacteraemia is a major contributor to global morbidity and mortality. Traditional culture-based methods lack sensitivity and are time-consuming. This study aimed to assess the effectiveness of two culture-independent assays, the MALDI-TOF-MS Sepsityper® module and the lateral flow inmunochromatography test (LFICT) with the Standard F® Streptococcus pneumoniae, directly from positive blood culture (BC) bottles., Methods: A prospective study was conducted from December 2021 to July 2022. For all BC positives for S. pneumoniae a double centrifugation protocol was implemented. The resulting pellet was subsequently processed using both techniques., Results: The LFICT showed exceptional performance with 100% sensitivity and specificity, outperforming the MALDI-TOF-MS Sepsityper® module, which achieved 85.2% sensitivity and 100% specificity. Nevertheless, the combination of these assays offers a robust and comprehensive approach to diagnosis., Conclusions: The simultaneous use of both techniques offers a promising alternative that can be integrated into routine practices directly from BC samples., (Copyright © 2024 Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. Published by Elsevier España, S.L.U. All rights reserved.)

Treatment assessment and patient outcome for sepsis depend predominantly on the timely administration of appropriate antibiotics 1-3 . However, the clinical protocols used to stratify and select patient-specific optimal therapy are extremely slow 4 . In particular, the major hurdle in performing rapid antimicrobial susceptibility testing (AST) remains in the lengthy blood culture procedure, which has long been considered unavoidable due to the limited number of pathogens present in the patient's blood. Here we describe an ultra-rapid AST method that bypasses the need for traditional blood culture, thereby demonstrating potential to reduce the turnaround time of reporting drug susceptibility profiles by more than 40-60 h compared with hospital AST workflows. Introducing a synthetic beta-2-glycoprotein I peptide, a broad range of microbial pathogens are selectively recovered from whole blood, subjected to species identification or instantly proliferated and phenotypically evaluated for various drug conditions using a low-inoculum AST chip. The platform was clinically evaluated by the enrolment of 190 hospitalized patients suspected of having infection, achieving 100% match in species identification. Among the eight positive cases, six clinical isolates were retrospectively tested for AST showing an overall categorical agreement of 94.90% with an average theoretical turnaround time of 13 ± 2.53 h starting from initial blood processing., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Purpose: Blood culture (BC) is the standard for diagnosing bloodstream infections. Available blood culture (BC) systems have been developed to shorten the time to detection (TTD) of positive BCs. This study aimed to evaluate the performance of the Mindray TDR automatic BC system by comparing it with the BacT/ALERT®3D system., Methods: Sixteen reference strains and 14 clinical isolates were used. Serial dilutions were prepared from all bacterial and yeast colonies with a final concentration of 100 CFU/ml and 10 CFU/ml. The prepared solutions were simultaneously inoculated into the bottles of both systems and placed in blood culture devices., Results: Three hundred and fifty-two (176 BacT/ALERT®3D and 176 Mindray TDR-X060) blood culture bottles were evaluated, 336 aerobic and 16 anaerobic. At both 10 CFU/ml and 100 CFU/ml dilution, there was no significant difference between the two systems in terms of mean detection times for all isolates ( p  = 0.965, p  = 0.245). When evaluated according to the type of organism, the detection time of gram-positive bacteria at 10 CFU/ml dilution was significantly shorter in the BacT/ALERT system ( p  = 0.019), whereas detection time for yeasts was significantly shorter with the Mindray system ( p  = 0.047). The number of anaerobic bacteria was too small to draw statistical conclusions, but we observed a trend of shorter detection times in the Mindray TDR-X060 system., Conclusion: Two systems with similar operating principles showed different concentrations-dependent performances in terms of positivity detection times depending on the type of microorganism. Mindray TDR-X060 system has been found to be safe to use at high concentrations with this at lower concentrations further comparative studies are needed on the newly introduced Mindray system.

Blood culturing (BC) remains the gold standard for bloodstream diagnosis but its workflow is slow. We aimed reducing this time by implementing a new automated incubator with a 24/7 BC workflow. With this new strategy, time to incubation was shorter (1.52 h vs 6.82 h), positivity rates were higher (10.6% vs 8.9%, p<0.05), and the number of BSI diagnostics increased (16.1% vs 13.8% patients and 2.3 vs 1.9 density episode per 1000 hospital days). Our results show that implementing automatic loading of BC bottles with a 24/7 strategy not only shortened time to diagnosis but significantly increased the BSI diagnosis rate., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Blood cultures are indispensable for detecting life-threatening bacteremia. Little is known about associations between contamination rates and topical disinfectants for blood collection in adults. We sought to determine whether a change in topical disinfectants was associated with the rates of contaminated blood cultures in the emergency department of a single institution. This single-center, retrospective observational study of consecutive patients aged 20 years or older was conducted in the emergency department (ED) of a university hospital in Japan between August 1, 2018 and September 30, 2020. Pairs of blood samples were collected for aerobic and anaerobic culture from the patients in the ED. Physicians selected topical disinfectants according to their personal preference before September 1, 2019; alcohol/chlorhexidine gluconate (ACHX) was mandatory thereafter, unless the patient was allergic to alcohol. Regression discontinuity analysis was used to detect the effect of the mandatory usage of ACHX on rates of contaminated blood cultures. We collected 2141 blood culture samples from 1097 patients and found 164 (7.7%) potentially contaminated blood cultures. Among these, 445 (20.8%) were true bacteremia and 1532 (71.6%) were true negatives. Puncture site disinfection was performed with ACHX for 1345 (62.8%) cases and with povidone-iodine (PVI) for 767 (35.8%) cases. The regression discontinuity analysis showed that mandatory ACHX usage was significantly associated with lower rates of contaminated blood cultures by 9.6% (95% confidence interval (CI): 5.0%-14.2%, P < 0.001). Rates of contaminated blood cultures were significantly lower when ACHX was used as the topical disinfectant., (© 2021. The Author(s).)

Patients with viral respiratory infections often present symptoms compatible with bloodstream infections. Consequently, the winter period commonly associated with epidemic respiratory illnesses shows an increase in the number of blood cultures (BC) and to occasional saturation of automated BC systems. Here, we explored the seasonal variations in BC samples and the potential impact of shortening the incubation time of BC when automated BC systems are close to saturation. A retrospective study was conducted during a 3-year period in 4 hospitals located in the Paris region, France. All aerobic and anaerobic bottles were included, except pediatric bottles and those sampled for suspicion of endocarditis. The number of BC bottles collected during the winter period was compared to the annual baseline. All bottles positive after a 4-day incubation were analyzed regarding clinical and microbiological findings. The number of BC bottles was significantly higher during the winter periods, compared to the annual baseline (up to 14%). A total of 292,349 BC bottles were analyzed with 23,363 (8.0%) positive, including 236 (1%) after a 4-day incubation. Of these 236 bottles, 76 (64.8%) were positive with a contaminant, 78 (33.1%) with a clinically significant microorganism identified for the same patient in the previous 4 days, and only 5 (2.1%) with a clinically significant microorganism not previously identified. Winter periods were associated with a significant increase in BC samples. Shortening the incubation time of BC bottles from 5 to 4 days seems a relevant option when automated BC systems are close to saturation., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Short incubation of positive blood cultures on solid media is now increasingly applied to speed up species identification by matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Although Columbia blood agar (CBA) and chocolate agar (Choc) are widely used, a direct comparison of standard agars is lacking. We therefore compared the time to species identification of blood cultures incubated on CBA, Choc, and MacConkey agar (MAC, for Gram-negative rods). Positive aerobic/anaerobic blood cultures (2 drops = 50 μl) were incubated on CBA, Choc, MAC, and the required time of incubation to low-confidence identification (score of ≥1.7 to <2) and high-confidence identification (score of ≥2) by MALDI-TOF MS was measured. Exclusion criteria were (i) false-positive blood cultures, (ii) mixed cultures with different species, (iii) growth of anaerobes/fungi, and (iv) a total number of isolates of one group (i.e., Gram-positive/-negative cocci/rods) of <30. A total of 187 blood cultures with Gram-positive cocci ( n  = 124) and Gram-negative rods ( n  = 63) were included in the final analysis. The shortest median time to high-confidence identification (score of ≥2) was achieved on MAC for Gram-negative rods (2.0 h; range, 1.9 to 4.2 h) and on CBA for Gram-positive cocci (4.0 h; range, 1.9 to 25.0 h). However, the difference from results obtained with Choc was not statistically significant. When only one agar plate is used for short incubation of positive blood cultures, Choc may represent a compromise in terms of time to high-confidence identification by MALDI-TOF MS and the bacterial spectrum that is covered. However, using only Choc is disadvantageous when the shortest incubation times to identification are strived for. IMPORTANCE When blood cultures are flagged as positive, they are incubated on solid media to produce enough biomass of the bacterium for identification and susceptibility testing. Rapid turnaround times for laboratory results could save lives, and we wanted to assess which solid medium is best to shorten the time to species identification using MALDI-TOF mass spectrometry. For that purpose, we used positive blood cultures from routine diagnostics and compared Columbia blood agar (CBA), Chocolate agar (Choc), and MacConkey agar (MAC, for Gram-negative rods). We found that MAC performed best for Gram-negative rods and CBA was quickest for Gram-positive cocci. However, Choc may represent a compromise if fastidious species should be covered.

Background: Rapid and accurate microbial identification and antimicrobial susceptibility testing (AST) are essential for timely use of appropriate antimicrobial agents for bloodstream infection. To shorten the time for isolating colonies from the positive blood culture, various preparation methods for direct identification using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) system were developed. Here, we evaluated the SepsiPrep kit (ASTA Corp.) for direct identification of microorganisms and AST from positive blood cultures using MicroIDSys Elite MALDI-TOF MS system (ASTA Corp.) and VITEK-2 system (bioMérieux)., Methods: For direct identification, a total of 124 prospective monomicrobial positive blood culture bottles were included. For direct identification, the pellet was prepared by centrifugation and washing twice. For direct AST, the pellet was suspended in 0.45% saline and adjusted to McFarland 0.5. The results from the direct identification and AST using MicroIDSys Elite and VITEK-2 system were compared to those from the conventional method performed with pure colony subcultured on agar plate., Results: Compared to the conventional method using pure colony, correct direct identification rate was 96.5% and 98.5% for 57 gram-positive isolates and 67 gram-negative isolates, respectively. For direct AST, among the 55 gram-positive isolates, the categorical agreement (CA) for staphylococci, streptococci, and enterococci was 96.7%, 98.4%, and 94.1%, respectively. For 66 gram-negative isolates, the CA for Enterobacterales and non-fermentative gram-negative rods was 99.0% and 96.6%, respectively., Conclusions: The SepsiPrep kit was easy to use combined with MicroIDSys Elite and VITEK-2 system and also, the correct identification and AST rate were very high., (© 2021 The Authors. Journal of Clinical Laboratory Analysis published by Wiley Periodicals LLC.)

A method for rapid detection of one extended-spectrum β-lactamase (ESBL) and five carbapenemase-encoding genes as well as vancomycin resistance markers directly from blood cultures using the Allplex™ Entero-DR assay (Seegene, Seoul, South Korea) is presented. Altogether 28 previously well-characterized resistant Gram-negative bacilli and Enterococcus spp., and 142 clinical blood cultures containing Gram-negative bacilli or Gram-positive cocci were analyzed. The method had 100% sensitivity and specificity for detecting bla OXA-48-like, bla KPC , bla VIM , bla IMP , bla NDM , bla CTX-M , vanA, and vanB. The lowest detectable amount of viable cells in blood culture samples were 5.39·10 4 CFU/mL, 6.66·10 4 CFU/mL, 5.13·10 3 CFU/mL, 6.09·10 4 CFU/mL, 6.66·10 4 CFU/mL, 6.66·10 4 CFU/mL, 3.12·10 4 CFU/mL, and 5.34·10 4 CFU/mL for the bla KPC , bla OXA-48-like , bla VIM , bla IMP , bla NDM , bla CTX-M , vanA, and vanB, respectively. The results were available within 90 min from signal positive blood cultures, as no separate DNA extraction steps were needed, and the assay showed no interference from blood or culture media used allowing reliable and simplified detection of the resistance markers.

Background/purpose: Rapid and accurate identification of pathogens and their antibiotic resistance directly from flagged blood cultures can aid clinicians in optimizing early antibiotic treatment and improve the clinical outcomes, especially in settings associated with high rates of bloodstream infection caused by vancomycin-resistant Enterococci (VRE) and carbapenem-resistant Enterobacteriaceae (CRE). We compared the results of the BioFire FilmArray Blood Culture Identification (BCID) panel with those of conventional methods for identifying the pathogens and their antibiotic susceptibility status., Methods: In total, 100 randomly selected positive blood cultures (BACTEC Plus Aerobic/F bottles or BACTEC Anaerobic Lytic/10 bottles) were analyzed. The pathogen detection efficiency of FilmArray BCID panel was compared with that of conventional method using MALDI-TOF MS system (Bruker MALDI Biotyper) and susceptibility testing by the Vitek 2 system. The sequencing analysis of antibiotic resistance genes was performed for discrepant results obtained from MALDI Biotyper and Vitek 2., Results: Among the 100 positively flagged blood cultures, 94% of FilmArray BCID panel results were consistent with the MALDI Biotyper results. All five VRE isolates positive for vanA/vanB genes, 10 of 12 Staphylococcus species positive for mecA gene, and only one Klebsiella pneumoniae isolate positive for K. pneumoniae carbapenemase gene (bla KPC ) detected in the FilmArray BCID panel were also concordant with results by the results by conventional susceptibility testing/molecular confirmation., Conclusions: The FilmArray BCID panel results not only demonstrated good correlation with conventional blood culture identification and susceptibility results but also provided results rapidly, especially for the early detection of MRSA, VRE and bla KPC -mediated CRE., Competing Interests: Declaration of Competing Interest The authors declare no conflicts of interest., (Copyright © 2020. Published by Elsevier B.V.)

The spread of carbapenemase-producing Enterobacterales is a major public health concern worldwide, and methods for their prompt and reliable detection are highly demanded for therapeutic and hygiene control purposes. In this study, we evaluate the MBT STAR ® -Carba assay (Bruker Daltonik) to detect the carbapenemase production in clinical and surveillance isolates from plate cultures and directly from patient-derived positive blood cultures bottles. Overall, n  = 1,307 samples were analyzed ( n  = 900 plate cultures, and n  = 407 positive blood cultures, using the bacterial pellet obtained with the Sepsityper ® Kit; Bruker Daltonik), including n  = 793 carbapenemase producers ( n  = 579 Klebsiella pneumoniae carbapenemase, n  = 161 metallo-beta-lactamases, n  = 45 OXA-48, and eight isolates harboring two different enzymes), n  = 239 carbapenem-resistant noncarbapenemase producers, and n  = 275 carbapenem-susceptible strains. The STAR-Carba assay detected 657/661 (99.4%) carbapenemase producers from plate cultures, and 132/132 (100%) from positive blood cultures. Specificity resulted in 100% for carbapenem-susceptible strains, and 91.6% for carbapenem-resistant strains resulted negative for carbapenamase production with the routine methods used in this study. In this study, the MBT STAR-Carba assay proved to be a highly reliable method for the detection of carbapenemase-producing Enterobacterales , regardless of the enzyme family, and from both plate cultures and positive blood culture bottles.

Background: The detection and identification of pathogenic microorganisms are essential for the treatment of osteoarticular infection. However, obtaining a sufficient amount of specimen from pediatric patients is often difficult. Herein, we aimed to demonstrate the effectiveness of the blood culture bottle (BCB) system in pediatric osteoarticular infections. We hypothesized that our BCB culture method is superior to the conventional swab and tissue culture methods in terms of required specimen size, incubation time, and microbial identification rate., Methods: We analyzed the prospectively collected data of pediatric patients who underwent surgical treatment for osteoarticular infections between August 2016 and October 2019. Four needles were dipped in the infected fluid or tissue during the surgical procedure as soon as the infected area was exposed and were used to inoculate 2 aerobic pediatric BCBs and 2 anaerobic general BCBs. We also collected 2 conventional swab samples and 2 tissue samples from the identical area. The microbial identification rate and the time required for identification were compared between BCB, swab, and tissue cultures., Results: Forty patients constituted the study group; 13 patients had osteomyelitis, 17 patients had septic arthritis, and 10 patients had both. Of these 40 patients, the microbial identification rate was higher with BCB cultures (27 [68%]) than with swab cultures (18 [45%]; p = 0.004) or tissue cultures (15 [38%]; p < 0.001). Nine samples (9 patients [23%]) were only positive in the BCB culture. Positive microbial growth was not detected with conventional culture methods when microorganisms did not grow on the BCB culture. Compared with swab culture (4.3 ± 1.1 days; p < 0.001) or tissue culture (4.4 ± 1.1 days; p < 0.001), the BCB culture reduced the time required for microbial identification (3.5 ± 0.9 days)., Conclusions: In pediatric osteoarticular infections, the BCB culture system improved the microbial identification rate, reduced the time to identification, and permitted a smaller-volume specimen, compared with traditional culture systems., Level of Evidence: Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Accelerate Pheno™ (ACC) is a fully automated system providing rapid identification of a panel of bacteria and yeasts, and antimicrobial susceptibility testing of common bacterial pathogens responsible for bloodstream infections and sepsis. Diagnostic accuracy for identification ranges from 87.9 to 100%, and antimicrobial susceptibility testing categorical agreement is higher than 91%. The present review includes peer-reviewed studies on ACC published to date. Both interventional and hypothetical studies evidenced the potential positive clinical role of ACC in the management and therapy of patients with bloodstream infections and sepsis, due to the important reduction in time to report, suggesting a crucial impact on the therapeutic management of these patients, provided the presence of a hospital antimicrobial stewardship program, a 24/7 laboratory operating time and a strict collaboration between clinical microbiologist and clinician. Further prospective multicenter studies are necessary to explore the impact of this system on mortality, length of stay and spread of multidrug-resistant organisms.

Background: Blood culture collection remains the gold standard to diagnose bacteraemia. Current evidence suggests that the emergency department (ED) often has blood culture contamination (BCC) rates above the recommended 3%, contributing to increased hospital length of stay, unnecessary or inappropriate antimicrobial treatment, and increased economic burden. The aim of this review is to identify effective strategies to improve blood culture collection in EDs to decrease contamination rates and improve patient safety., Methods: An integrative literature review methodology was utilised to conduct a structured search of contemporary literature using CINAHL, Embase, Medline, Pubmed and Scopus databases. All eligible literature was screened with those included in the final review collated and appraised using a quality assessment tool., Results: Eleven reports were included in the final review, which identified bundled approaches, education and feedback, equipment and technique, and stakeholder engagement as strategies that improve BCC rates in the ED., Conclusions: All studies reported a reduction in BCC rates regardless of the strategies implemented. A bundled approach yielded the most significant results and was identified to be practical, inexpensive, and adaptable. Further research focusing on specific aspects of a bundled approach may be beneficial to understand which strategies are most effective., (Copyright © 2020 College of Emergency Nursing Australasia. Published by Elsevier Ltd. All rights reserved.)

Purpose: We analyzed the workflow of the blood culture procedure with one blood culture incubator in the microbiology laboratory, in comparison with the workflow with the incubators systems placing outside, and in a microbiology laboratory without 24-h staffing., Methods: We assessed the elapsed time (ET) and time-to-result (TTR) in the two laboratory workflows during 1 month period in consecutive years. First period with one BACT/ALERT 3D module located in the microbiology laboratory (ML) (access 8 a.m. to 10 p.m.) and second period with three BACT/ALERT VIRTUO modules (one located in ML and two in the core sample laboratory, access 24 h)., Results: The mean ET with BACT/ALERT 3D was 7.09 ± 6.15 h and 1.32 ± 3.14 h with BACT/ALERT VIRTUO. During the 8:00 a.m. to 10:00 p.m. shift, the average ETs were 3.54 ± 5.06 vs 1.59 ± 1.29 h for the two time periods, respectively. Since the automated loading of bottles on the BACT/ALERT VIRTUO allows processing of blood cultures during the night shift, there was a significant reduction of time during the 10:00 p.m. to 8:00 a.m. shift, where the average ET was 10.52 ± 5.23 vs 1.00 ± 4.40 h, respectively. The percentage of positivity in the first period was 9.03% and 11.18% in the second (p = 0.0003). The average TTR in the first period was 24.78 ± 15.9 h and 16.85 ± 14.13 h in the second (p < 0.0001)., Conclusions: Easy 24-h access to blood culture incubators resulted in significant improvement in the workflow of blood culture, decreasing ET, and therefore decreasing the time to positivity and the efficiency of recovery.

The in vitro susceptibilities of Bacteroides fragilis to antimicrobial agents, especially to carbapenem, are a major concern in the treatment of patients with bloodstream infections. In this study, 50 isolates of B. fragilis were obtained from positive blood bottles from 2014 to 2019 in Saitama, Japan. Their susceptibility to ampicillin/sulbactam was reduced to 70.0% compared with a previous report, whereas they were still sufficiently susceptible to piperacillin/tazobactam (94.0%). Five cfiA-positive isolates (5/50, 10.0%) were identified that were resistant to doripenem and meropenem, and two of them carried an insertion sequence located upstream of the cfiA-coding region. In particular, imipenem should be considered as a first-line carbapenem for the empirical treatment of B. fragilis infection because only insertion sequence and cfiA double-positive strains showed resistance to imipenem. Thirty-six percent of the isolates had a reduced minimum inhibitory concentration for moxifloxacin. In addition, metronidazole should still be considered as an active agent for B. fragilis because all isolates were susceptible to this antibiotic and the prevalence of the nim gene was low in Japan., Competing Interests: Declaration of competing interest Nothing to declare., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Aim: Detection of coagulase-negative Staphylococcus in blood culture may be a result of either bacteremia or contamination. This often leads to diagnostic uncertainly. Our objective was to develop a method for differentiating whether a coagulase-negative Staphylococcus sp. positive blood culture represents bacteremia or contamination based on positive bottle detection pattern and time to positivity (TTP)., Methods: This study included 155 and 51 adults with positive blood cultures for Staphylococcus epidermidis and Staphylococcus hominis, respectively, over a three-year period from 2016 to 2018. Positive blood culture cases were categorized as either bacteremia or contamination based on the clinically available information, and the detection pattern and TTP in each category were investigated., Results: A total of 57, 92, and 6 S. epidermidis positive blood cultures were categorized as bacteremia, contamination, and undetermined, respectively, whereas 15 and 36 S. hominis positive blood cultures were categorized as bacteremia and contamination, respectively. For positive blood cultures categorized as bacteremia, all four bottles in two sets of blood cultures were positive in 47/47 S. epidermidis and 14/14 S. hominis, respectively, whereas either one bottle in each of two sets or three bottles in two sets were positive in 10/19 S. epidermidis and 1/4 S. hominis, respectively; most of those TTPs were <48 h. Among them, the TTP in catheter-related blood stream infection was <24 h., Conclusion: Although clinical assessment is crucial to differentiate between bacteremia and contamination, a combination of positive bottle detection pattern and TTP is a valuable diagnostic auxiliary tool., Competing Interests: Declaration of Competing Interest All authors confirm that there are no conflicts of interest to declare., (Copyright © 2020 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

The objectives of this study were to define the shortest incubation times on the WASPLab for reliable MALDI-TOF/MS-based species identification and for the preparation of a 0.5 McFarland suspension for antimicrobial disk diffusion susceptibility testing using short subcultures growing on solid culture media inoculated by positive blood cultures spiked with a wide range of pathogens associated with bloodstream infections. The 520 clinical strains (20 × 26 different species) included in this study were obtained from a collection of non-consecutive and non-duplicate pathogens identified at Geneva University Hospitals. After 4 h of incubation on the WASPLab, microorganisms' growth allowed accurate identification of 73% (380/520) (95% CI, 69.1-76.7%) of the strains included in this study. The identification rate increased to 85% (440/520) (95% CI, 81.3-87.5%) after 6-h incubation. When excluding Corynebacterium and Candida spp., the microbial growth was sufficient to permit accurate identification of all tested species (100%, 460/460) (95% CI, 99.2-100%) after 8-h incubation. With the exception of Burkholderia cepacia and Haemophilus influenzae, AST by disk diffusion could be performed for Enterobacterales and non-fermenting Gram-negative bacilli after only 4 h of growth in the WASPLab. The preparation of a 0.5 McFarland suspension for Gram-positive bacteria required incubation times ranging between 3 and 8 h according to the bacterial species. Only Corynebacterium spp. required incubation times as long as 16 h. The WASPLab enables rapid pathogen identification as well as swift comprehensive AST from positive blood cultures that can be implemented without additional costs nor hands-on time by defining optimal time points for image acquisition.

Background: Obligate anaerobes usually account for less than 10% of bacteria recovered from blood cultures (BC). The relevance of routine use of the anaerobic bottle is under debate. The aim of this study was to evaluate the utility of anaerobic bottles for the diagnosis of bloodstream infections (BSI)., Methods: We conducted a 6-month, retrospective, monocentric study in a tertiary hospital. All positive BC were grouped into a single episode of bacteremia when drawn within 7 consecutive days. Bacteremia were classified into contaminants and BSI. Charts of patients with BSI due to obligate anaerobes were studied., Results: A total of 19,739 blood cultures were collected, 2341 of which (11.9%) were positive. Anaerobic bottles were positive in 1528 (65.3%) of all positive BC but were positive alone (aerobic bottles negative) in 369 (15.8%). Overall 1081 episodes of bacteremia were identified, of which 209 (19.3%) had positive anaerobic bottles alone. The majority 126/209 (60.3%) were contaminants and 83 (39.7%) were BSI. BSI due to facultative anaerobes, obligate aerobes and obligate anaerobes were identified in 67 (80.7%), 3 (3.6%) and 13 (15.7%) of these 83 episodes, respectively. BSI due to obligate anaerobic bacteria were reported in 9 patients with gastro-intestinal disease, in 3 with febrile neutropenia and in 1 burned patient., Conclusions: Anaerobic bottles contributed to the diagnosis of a significant number of episodes of bacteremia. Isolated bacteria were mostly contaminants and non-obligate anaerobic pathogens. Rare BSI due to obligate anaerobes were reported mainly in patients with gastro-intestinal disorders and during febrile neutropenia.

Reporting of the results of routine laboratory blood culture tests to clinicians is vital to the patients' early treatment. This study aimed to perform identification and antibiotic susceptibility tests of the blood cultures showing positive signals of microbial growth in the first 12 hours of incubation by using centrifugation and Gram staining of 5 ml of liquid from the vial, thus achieving faster results. This study included 152 consecutively incubated blood culture samples showing positive microbial growth signals in the first 12 hours. The samples were centrifuged and then categorized into two groups (Gram-positive and Gram-negative) using Gram staining. Identification and antibiotic susceptibility tests were performed using an automated culture antibiogram device. For routine processing, media inoculated with positive blood culture were kept in the incubator for at least 24 hours. To compare the two methods in terms of the bacteria identification, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) of the growing colony was studied. By Gram staining, the same bacterial strains were obtained for 138 (92%) of the 152 samples, similar to the results of the procedures mentioned earlier. With the samples tested with both methods, the antibiotic susceptibility profiles were compared using the antibiogram results for 1,984 samples that underwent the antibiotic testing. A 97.4% (for 1,934 antibiotic susceptibility assays) agreement was observed between the two methods. Comparing the results of the post-centrifugation Gram staining to those obtained for the specimens using routine procedures, the clinicians reported a high success rate (approximately 97%)., Reporting of the results of routine laboratory blood culture tests to clinicians is vital to the patients’ early treatment. This study aimed to perform identification and antibiotic susceptibility tests of the blood cultures showing positive signals of microbial growth in the first 12 hours of incubation by using centrifugation and Gram staining of 5 ml of liquid from the vial, thus achieving faster results. This study included 152 consecutively incubated blood culture samples showing positive microbial growth signals in the first 12 hours. The samples were centrifuged and then categorized into two groups (Gram-positive and Gram-negative) using Gram staining. Identification and antibiotic susceptibility tests were performed using an automated culture antibiogram device. For routine processing, media inoculated with positive blood culture were kept in the incubator for at least 24 hours. To compare the two methods in terms of the bacteria identification, matrix‐assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI‐TOF MS) of the growing colony was studied. By Gram staining, the same bacterial strains were obtained for 138 (92%) of the 152 samples, similar to the results of the procedures mentioned earlier. With the samples tested with both methods, the antibiotic susceptibility profiles were compared using the antibiogram results for 1,984 samples that underwent the antibiotic testing. A 97.4% (for 1,934 antibiotic susceptibility assays) agreement was observed between the two methods. Comparing the results of the post-centrifugation Gram staining to those obtained for the specimens using routine procedures, the clinicians reported a high success rate (approximately 97%).

Background : The comparison of the performance of FAPlus/FNPlus bottles and combination of SA/SN and FA/FN bottles is not yet reported. Methods : We used human blood samples to investigate microorganism detection rates and the time to positivity (TTP) in a before-vs.-after study (a combination of SA/SN and FA/FN bottles from September 2012 to August 2013 vs. FAPlus/FNPlus bottles from September 2013 to August 2014). Results : The microorganism detection rate was significantly higher in the later period than in the earlier period (11.2% vs. 9.6%, P < 0.001), particularly for Enterococcus and Streptococcus species, nonfermentative Gram-negative bacilli, and Helicobacter cinaedi. TTP for pathogens was longer when FAPlus/FNPlus bottles were used than when a combination of SA/SN and FA/FN bottles was used (14.9 vs. 13.3 h, P = 0.014), particularly, in the case of Gram-negative bacilli including Escherichia coli. Conclusion : The microorganism detection rate was improved with the use of FAPlus/FNPlus bottles compared with the combination of SA/SN and FA/FN bottles ; however, FAPlus/FNPlus bottles seemed to be inferior to SA/SN and FA/FN bottles in terms of TTP. J. Med. Invest. 67 : 90-94, February, 2020.

Introduction: Acute appendicitis is the first cause of acute abdomen, however, there is a little information about the associated bacteria and its sensibility profile. Objetive: To identify and to determine the resistance pattern of aerobic and anaerobic bacteria isolated in periapendicular fluid cultures taken in patients with acute appendicitis and to establish the proportions of isolates according to the clinical phase. Materials and methods: A descriptive and prospective study was undertaken at the Hospital Universitario de San José (Bogotá, Colombia) of patients older than sixteen years of age, undergoing an open appendectomy. A sample of periappendiceal fluid was taken, which was deposited directly into aerobic and anaerobic blood culture bottles. Results: One hundred and fifty-four patients were included. The overall positivity of cultures was 87% (n=1344); 77% (n=118) for aerobes and 51% (n=79) for anaerobes. The proportion of positive cultures was lower in the uncomplicated appendicitis cases as compared to the complicated ones (80% (66/83) vs. 95%(67/71), p = 0.003). The microorganisms isolated most frequently were: Escherichia coli (53%) (n=84); Bacteroides spp. (25%) (n=25); Propionibacterium acnes (21%) (n=21); coagulase negative Staphylococci (17%) (n=27); Enterococcus spp. (11%) (n=15), and Fusobacterium spp. (11%) (n=11). The sensitivity of E. coli to ampicillin/sulbactam was 30%. The sensitivity of Bacteroides spp. to clindamycin and ampicillin/sulbactam was 91%. All anaerobe isolates were sensitive to piperacillin/tazobactam, ertapenem, meropenem and metronidazole. Conclusions: Intraoperative cultures in acute appendicits are relevant in order to determine the local epidemiological pattern and to establish prophylactic and therapeutic antibiotics for this pathology; direct inoculation in blood culture bottles allows a high recovery of microorganisms.

Continuous monitoring of the performances of blood culture instrument can be based on the indicators proposed by the QUAMIC. Of these, the analytic performance indicator evaluates the rate of false-positive vials. False-positives vials can be reported by the device in case of leukocytosis or when vials are overfilled. In our laboratory, we record prospectively in our software all false positive vials as well as the position used for their incubation. These data are analyzed at least twice a year. For the first half of 2016, this strategy allowed us to identify a defective position. We then evaluated the impact of this anomaly as very weak. The one-year follow-up after the position repair confirmed a correction of the problem. Thus, traceability of positions reporting unexplained false-positive vials (i.e. neither due to leukocytosis nor overfilled vials) can allow laboratories to identify a defective position. This survey, if done prospectively, is simple to perform and not time-consuming. It could usefully complement the analytical performance indicator based on the false-positive rate.

The present study assessed the performance of Rapid Polymyxin™ NP test to detect colistin resistance directly from 132 blood cultures found positive for Enterobacterales by FilmArray. Additionally, colistin MICs of isolated microorganisms were determined by the commercial broth microdilution method ComASP™ Colistin, used as the gold standard comparator. The Rapid Polymyxin™ NP test correctly detected all colistin-resistant isolates. However, the test has misidentified as resistant 4 colistin-susceptible isolates (1 Escherichia coli and 3 Klebsiella pneumoniae). Molecular characterization of colistin-resistant isolates showed that K. pneumoniae, which belonged to ST15 and ST147, carried alterations in the mgrB. Moreover, the first Greek mcr-1-positive colistin-resistant E. coli was detected. The rapidity (2-3 h) of the results, combined with its excellent negative predictive value (100%), allows implementation of the test for routine testing of blood cultures mainly in the clinical settings that are endemic for carbapenem-resistant bacteria, avoiding misuse of colistin and preventing the spread of colistin-resistant bacteria., (Copyright © 2019 Elsevier Inc. All rights reserved.)

The performance of BACT/ALERT FA and FN PLUS (FA PLUS and FN PLUS) blood culture bottles with the BACT/ALERT VIRTUO (bioMérieux, Inc., Durham, NC) and BD BACTEC Plus Aerobic and Anaerobic (BD Aerobic and BD Anaerobic) blood culture bottles with the BD BACTEC FX (BD Diagnostics, Sparks, MD) for antimicrobial neutralization at peak serum concentration was evaluated. The following antibiotic agents and microbial strains were used: ampicillin, cefepime, cefotaxime, gentamicin, levofloxacin, meropenem, piperacillin-tazobactam, and vancomycin; methicillin-sensitive Staphylococcus aureus, Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Bacteroides fragilis. The detection rate of FA PLUS bottles was 69.1% (259/375) and that of BD Aerobic bottles was 75.5% (283/375) (p = 0.050). In the case of anaerobic culture, the overall detection rate of FN PLUS bottles was 77.0% (231/300) and that of BD Anaerobic bottles was 71.3% (214/300) (p = 0.113). The time to detection (TTD) from aerobic culture was 2.8 h shorter in FA PLUS bottles (12.4 h) compared to BD Aerobic bottles (15.2 h) (p < 0.001). And the TTD from anaerobic culture was 1.6 h shorter in FN PLUS bottles (18.1 h) compared to BD Anaerobic bottles (19.7 h) (p = 0.061). The FA PLUS bottles exhibited a lower detection rate compared to BD Aerobic bottles, while FN PLUS bottles showed a higher detection rate compared to BD Anaerobic bottles. The BACT/ALERT VIRTUO system exhibited shorter TTD compared to the BD BACTEC FX system for both aerobic and anaerobic cultures.

Competing Interests: No potential conflicts of interest relevant to this article were reported.

Objectives: To analyse and compare the ability of procalcitonin (PCT), C-reactive protein (CRP) and leukocytes to differentiate true bacteraemia from contaminated blood cultures in patients seen in the emergency department (ED) for an episode of infectious disease., Methods: Observational, retrospective and descriptive analytical study of all blood cultures with positive growth extracted in an ED in adult patients (≥18 years) during 2016 and 2017. The follow-up was carried out over a 30-day period to calculate the predictive power and the prognostic performance for true bacteraemia., Results: A total of 266 blood cultures with positive growth were included in the study. Out of these, 154 (57.9%) were considered true bacteraemia and 112 (42.1%) were considered to be contaminated blood cultures. The area under the Receiver Operating Characteristic curve (AUC-ROC) for PCT to predict true bacteraemia was 0.983 (95% CI: 0.972-0.994; P<0.001) and, considering a cut-off value of≥0.43 ng/ml, PCT achieved 94% sensitivity, 91% specificity, positive predictive value of 94%, and negative predictive value of 92%. The AUC-ROC obtained for CRP was 0.639 (95% CI: 0.572-0.707, P<.001), for leukocytes of 0.693 (95% CI: 0.630-0.756, P<.001) and for immature leukocytes (>10% bands) of 0.614 (95% CI: 0.547-0.682, P<.001). The mean values for PCT were 3.44 (SD 6.30) ng/ml in true bacteraemia vs. 0.16 (SD 0.18) ng/ml in contaminated blood cultures (P<.001)., Conclusions: In blood cultures with positive growth extracted in an ED, PCT achieves the best prognostic performance of true bacteraemia vs. contaminated blood cultures, better than CRP and leukocytes., (Copyright © 2019 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.)

Objectives: Bloodstream infections in critically ill require a speeded-up microbiological diagnosis to improve clinical outcomes. In this pre-post intervention study, we evaluated how a molecular identification test directly performed on positive blood cultures of critically ill improves patient's therapeutic management., Methods: All adult patients staying at the intensive care unit (ICU) at the time of positive blood culture detection were study-eligible. In the 8-month pre-intervention period (P0), standard positive blood culture management was performed. In the 10-month intervention period (P1), a BioFire® FilmArray® blood culture identification (FA-BCID) test (bioMérieux) was additionally performed 24/7 at detection. The evaluated clinical outcome was time to optimal antimicrobial treatment of the bloodstream infection. FA-BCID microbiological test performances were also analysed., Results: 163 positive blood culture episodes were allocated to P0 and 166 to P1. After the withdrawal of episodes in accordance with defined exclusion criteria, outcome analysis was performed on 110 bloodstream infections both in P0 and P1. Time to optimal antimicrobial treatment in P0 was 14h41 compared to 4h39 in P1. FA-BCID test results led to a treatment adjustment in 35/110 (31.8%) P1 episodes including 26 where the adjustment was the optimal antimicrobial treatment. FA-BCID testing identified 96.2% of the on-panel microorganisms thereby covering 85.2% of our ICU-strain epidemiology. Time to identification with FA-BCID testing was calculated at 1h35. Resistance detection was in complete concordance with routine results. Considering 150 FA-BCID tests were initially performed in P1, 4,3 tests were required to have 1 test leading to an improved therapeutic outcome., Conclusions: FA-BCID testing drastically reduced time to optimal antimicrobial treatment in critically ill with bloodstream infections., Competing Interests: This work was funded by BioFire Diagnostics (Salt Lake City, Utah) (https://www.biomerieux-usa.com/clinical/biofire-film-array). BioFire Diagnostics supplied 2 FilmArray systems as well as the FA-BCID tests to perform the study. This does not alter our adherence to PLOS ONE policies on sharing data and materials. The authors have no other relevant declarations relating to employment, consultancy, patents, products in development, marketed products.

The diagnosis of bloodstream infection requires the optimum combination of media in an automated blood culture system for maximum recovery of pathogens with the earliest time to detection. In a previous work, we showed that for patients admitted to the Emergency Department of our hospital, the combination of BACTEC lytic anaerobic and BACTEC aerobic vials was more efficient than BACTEC anaerobic and BACTEC aerobic vial. In this study, we extended the work including a broader patient population, representative of all hospital. A total of 8629 cultures were collected during the pre-lytic phase, from 01 July 2013 to 30 June 2014 and 7940 cultures during the post-lytic phase, ranged from 01 July 2015 to 30 June 2016. The number of positive blood cultures was higher during the post-lytic phase (19.74%) than in the pre-lytic phase (17.52%), particularly for Escherichia coli, Staphylococcus spp., Enterococcus spp., and anaerobes. We also observed a significant decreased of the time to detection, with the mean and median in the post-lytic phase of 17.68 and 13.05 h compared with 19.49 and 14.47 h in the pre-lytic phase. Whereas the time to detection was the same for organisms recovered in the aerobic Plus bottles for both time periods, time to detection for the anaerobic lytic bottles was significantly faster than with the anaerobic Plus bottles. This study carried out on a long time observation reported that a simple modification of composition of blood culture set could lead to better results in bloodstream infection detection.

Blood volume is the most important variable for the detection of microorganisms in blood cultures (BCs). Most standards recommend 40 to 60 ml blood, collected in several BC bottles filled up to 10 ml. We measured blood volume in individual BC bottles and analyzed the associations of hospital, bottle type, day of the week, daily sampling time, and age and sex of the patient with sampling volume and BC result. The variation in blood volume per BC bottle was analyzed in a mixed linear model using hospital, bottle type, weekday, sampling time, age, and sex as fixed factors and patient identification (ID) and episode as random factors to control for repetitive sampling of individual patients. Only 18% of all bottles were filled with the recommended 8 to 10 ml, and 47% were filled with less than 8 ml. The mean (± standard error) volume was larger in positive bottles (9.09 ± 0.15) than in negative bottles (8.47 ± 0.07) ( P < 0.001). Blood volume was larger in BacT/Alert-FA Plus bottles than in -FN Plus BC bottles ( P < 0.001). There were significantly lower volumes collected during the night ( P < 0.001). The volume of blood collected decreased significantly with increasing patient age ( P < 0.001). Larger volumes were collected from male patients than from female patients: 8.78 (± 0.06) versus 8.36 (± 0.06) ml (mean ± standard error [SE]), respectively ( P < 0.001). The odds of detecting a positive patient increases by 13% for each additional milliliter of blood drawn. Our results show that we need to work actively with the development of blood sampling routines to overcome age and sex effects and to optimize blood sampling volumes., (Copyright © 2019 American Society for Microbiology.)

Background: Blood culture bottles (BCBs) provide a semiautomated method for culturing periprosthetic tissue specimens. A study evaluating BCBs for culturing clinical samples other than body fluids is needed before implementation into clinical practice. Our objective was to evaluate use of the BacT/Alert® Virtuo blood culture system for culturing periprosthetic tissue specimens., Methods: The study was performed through the analysis of spiked (n = 36) and clinical (n = 158) periprosthetic tissue samples. Clinical samples were analyzed by the BCB method and the results were compared to the conventional microbiological culture-based method for time to detection and microorganisms identified., Results: The BacT/Alert® Virtuo blood culture system detected relevant bacteria for prosthetic joint infection in both spiked and clinical samples. The BCB method was found to be as sensitive (79%) as the conventional method (76%) (p = 0.844) during the analyses of clinical samples. The BCB method yielded positive results much faster than the conventional method: 89% against 27% detection within 24 h, respectively. The median detection time was 11.1 h for the BCB method (12 h and 11 h for the aerobic and the anaerobic BCBs, correspondingly)., Conclusion: We recommend using the BacT/Alert® Virtuo blood culture system for analyzing prosthetic joint tissue, since this detect efficiently and more rapidly a wider range of bacteria than the conventional microbiological method.

Blood culture is the most critical examination for diagnosing bacterial infections. The longer the blood culture incubation period, the higher the chances of identifying bacterial strains. However, unnecessary extension of the incubation period can burden the capacity of the instrument and merely result in the detection of contaminant bacteria having no clinical significance. This study aimed to optimize the blood culture incubation period using the currently available continuous-monitoring automated blood culture instrument. This was a 2-year retrospective study performed at Osaka University Hospital (January 1, 2016 to December 31, 2017). The BD BACTEC™ FX blood culture system (Becton Dickinson, Sparks, MD, USA) and BD BACTEC™ Plus series blood culture bottles were used. All blood cultures were incubated for more than 12 consecutive days. We reviewed the clinical data of cases that tested positive between 6 and 12 days of incubation. During the study period, 14,822 sets of blood culture were drawn. Of 1751 sets testing positive, 95.7% (1665 sets) became positive within 5 days of incubation. The overall contamination rate (false positives) after 6 days of incubation was 80.2% (69/86 sets). Based on the positive blood culture results, antimicrobials were changed in 7.0% (6/86) of the sets, and a diagnosis of infectious disease was made in only one case. There was no death associated with the extended blood culture results. In conclusion, the clinical impact of extended blood culture incubation for 6 days or more was limited, and a routine extension of the incubation period might be unnecessary., (Copyright © 2019 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Background: The purpose of this meta-analysis was to evaluate the diagnostic accuracy of periprosthetic tissue culture in blood culture bottles (BCB) for periprosthetic joint infection (PJI)., Methods: PubMed, Web of Science, and Embase were systematically searched for eligible studies evaluating the diagnostic performance of periprosthetic tissue culture in BCB for the diagnosis of PJI. The pooled data were analysed by Meta-Disc software., Results: Four studies with a total of 1071 patients were included in this meta-analysis. The summarized estimates showed that periprosthetic tissue culture in BCB may be of great value in PJI diagnosis with a pooled sensitivity of 0.70 (95% confidence interval [CI]; 0.66-0.75), specificity of 0.97 (95% CI: 0.95-0.98); positive likelihood ratio (PLR) of 20.98 (95% CI: 11.52-38.2); negative likelihood ratio (NLR) of 0.28 (95% CI: 0.20-0.40); and diagnostic odds ratio (DOR) of 92.26 (95% CI: 43.93-193.78)., Conclusions: The present meta-analysis showed that periprosthetic tissue in BCB improves the results of microorganism cultures, with a sensitivity of 70% and a specificity of 97%. However, more large-scale, well-performed studies are needed to verify our findings.

Background: Candidemia is an emerging hospital-acquired bloodstream infection (BSI). It is common among severely ill and immunocompromised patients. Even following appropriate therapy in candidemia, recent studies reveal relative high mortality (40%). The global incidence of candidemia shows an incline. In Sri Lanka, candida speciation often difficult where basic facilities are less available. We have compared the risk factors, epidemiology, demography, and performance of HiChrome Candida differential agar (HiCA) characteristics with the VITEK2 YST platform for differentiation of Candida albicans (CA) and non-albicans candida (NAC) from blood culture isolate., Methods: This is a laboratory-based cross-sectional study. Positive aerobic BACTEC blood cultures having yeast were identified using HiCA and VITEK2® platform. Epidemiology, risk factors, and clinical outcomes were compared between CA and NAC bloodstream isolates., Results: Out of 120 positive yeast samples, VITEK2® has identified 110 (92%) as Candida sp. From that CA-34 (31%) and NAC-76 (69%) were isolated. Candidemia following NCA in neonates (p = 0.02), infants (p = 0.04) and adults (p = 0.02) in ICU and immunocompromised patients were significantly higher. Compared to CA, NAC bacteremia period prevalence (0.00041%) and incidence (0.23 per 100,000-person-years) was significantly high (p = 0.03). NAC 48 (63%) isolates were resistance to azoles. Exposure to antifungals (odds ratio (OR); p = 0.03), prolonged intensive care stay > 14 days (OR-3.3; p = 0.04), having a central venous line for > 8 days (OR-4.3; p = 0.03) and on immunosuppressive treatment (OR-2.4; p = 0.04) was significantly poses risk for NAC candidemia. Sen day mortality was significant among non-albicans cases (p = 0.03) while 30-day mortality was significant among albicans cases (p = 0.04). Compared to VITEK2®, the HiCA method was 93% sensitive and 93% specific in detecting CA., Conclusion: Compared to CA, candidemia following NAC was high. NAC isolates were having a high percentage of fluconazole and voriconazole resistance. VITEK2 YST® platform provides antifungal susceptibility with minimal inhibitory concentration (MIC). Impact, this would highlight the use of rapid candida identification flat form with MIC to direct appropriate antifungals for candidemia. For that implementation of novel diagnostic facilities like the VITEK2 YST platform at a tertiary care facility is demanding.

Competing Interests: Competing interests: None declared.

Background: BacT/Alert Virtuo (BioMérieux, Durham, NC, USA) is a recently developed blood culture system that includes functions of automatic registration, loading, and unloading of the blood culture bottles, as well as measurement of blood volume. We compared the performances between the BacT/Alert Virtuo and 3D (BioMérieux) blood culture systems., Methods: A total of 952 patients (1,904 sets) visiting an university-affiliated hospital in Korea for blood cultures were enrolled. Five milliliters of blood was added into each of the two aerobic (FA Plus) and two anaerobic (FN Plus) bottles of the Virtuo and 3D systems for a single set. Positive rate and time to detection (TTD) were compared between the two systems., Results: The positive rates were 8.3% and 8.4% in FA Plus bottles and 7.8% and 8.3% in FN Plus bottles, in the Virtuo and 3D systems, respectively ( P >0.05). Median TTDs were shorter in the Virtuo than in the 3D system for all isolates (11.5 hours [N=305] vs 11.8 hours [N=318], P <0.001), Staphylococcus aureus (N=38; 14.3 hours vs 16.0 hours, P =0.021), and Escherichia coli (N=117; 10.4 hours vs 11.0 hours, P <0.001)., Conclusions: The Virtuo has the potential to detect pathogens early in all bottle types. This might improve the prognosis of sepsis by allowing for implementation of expeditious management., Competing Interests: This work was technically supported by bioMeriux Korea. The authors were not influenced during data collection, interpretation, and writing of the manuscript by the company., (© The Korean Society for Laboratory Medicine.)

Blood cultures are the most valuable tool when bacteremia is clinically suspected. Technical advances have led to the development of automated blood culture systems to detect bacterial infections. Usually positive signals in automated blood culture systems result from the proliferation of microorganisms. Cases are classified as false-positive when the automated blood culture system produces a positive signal but no microorganisms are detected on Gram-stained smears and no microorganism growth is observed in blood subcultures. False-positive blood culture results are very rare in patients with hematologic malignancies. Recently, we encountered four patients who had false-positive blood culture results. Two of the patients were diagnosed with acute leukemia, involving hyperleukocytosis and an excess of blasts. The other two patients were diagnosed with acute leukemia and diffuse large B cell lymphoma with leukocytopenia. Although hypercapnia or acidosis, apart from hyperleukocytosis, might also cause false-positive results, our cases clearly did not have these conditions. We should be aware of the possibility that false-positive blood culture results can occur in patients with leukocytopenia, as well as hyperleukocytosis. To understand the mechanisms responsible for the observed false-positive results, additional studies are needed after the accumulation of similar cases., (Copyright © 2019. Published by Elsevier Ltd.)

Objectives: Underfilling of blood culture bottles decreases the sensitivity of the culture. We attempt to increase average blood culture fill volumes (ABCFVs) through an educational program., Methods: Partnerships were established with four hospital units (surgical intensive care unit [SICU], medical intensive care unit [MICU], medical intermediate care unit [MIMCU], and hematology and oncology unit [HEME/ONC]). ABCFVs were continuously tracked and communicated to each unit monthly. Educational sessions were provided to each unit., Results: ABCFVs for the SICU, MICU, MIMCU, and HEME/ONC were 4.8, 5.0, 5.0, and 6.3 mL/bottle, respectively. After the final education session, the SICU, MICU, MIMCU, and HEME/ONC were able to maintain an ABCFV of 6.8, 8.1, 7.9, and 8.2 mL/bottle, respectively., Conclusions: Partnering with a specific unit and providing monthly volume reports with educational sessions has a direct positive correlation on increasing ABCFVs. Increasing ABCFVs has the potential to decrease false-negative blood cultures, time to detection of positive blood cultures, and time to appropriate and specific antimicrobial therapy, as well as improve patient outcomes in high-acuity patient care units.

Background: Advances in medicine have improved our understanding of sepsis, but it remains a major cause of morbidity and mortality. The detection of pathogens that cause sepsis remains a challenge for clinical microbiology laboratories., Content: Routine blood cultures are time-consuming and are negative in a large proportion of cases, leading to excessive use of broad-spectrum antimicrobials. Molecular testing direct from patient blood without the need for incubation has the potential to fill the gaps in our diagnostic armament and complement blood cultures to provide results in a timely manner. Currently available platforms show promise but have yet to definitively address gaps in sensitivity and specificity., Summary: Significant strides have been made in the detection of pathogens directly from blood. A number of hurdles, however, remain before this technology can be adapted for routine use., (© 2018 American Association for Clinical Chemistry.)

Background: Fast diagnostic tests providing earlier identification (ID) of pathogens, and antimicrobial susceptibility testing (AST) may reduce time to appropriate antimicrobial therapy (AAT), decrease mortality, and facilitate antimicrobial deescalation (ADE). Our objective was to determine the theoretical reduction in time to AAT and opportunities for ADE with Accelerate Pheno TM System (AXDX)., Methods: The prospective cohort (April 14, 2016 through June 1, 2017) was from the Barnes-Jewish Hospital, a 1250-bed academic center. Emergency department (ED) or intensive care unit (ICU) blood cultures Gram-stain positive for gram-negative bacilli (GNB) or yeast. AXDX was used in parallel with standard-of-care (SOC) diagnostics to determine differences in time to pathogen ID and AST. Theoretical opportunities for ADE from AXDX results were determined., Results: In total, 429 blood cultures were screened, 153 meeting inclusion criteria: 110 on-panel GNB, 10 Candida glabrata , and 5 Candida albicans . For GNB SOC, median time from blood culture positivity to ID and AST were 28.2 and 52.1 h. Median time to ID and AST after AXDX initiation was 1.37 and 6.7 h for on-panel organisms. For on-panel Candida , time to ID was approximately 21 h faster with AXDX. ADE or AAT was theoretically possible with AXDX in 48.4%. Of on-panel organisms, 24.0% did not receive initial AAT. In-hospital mortality was 46.7% without initial AAT, and 11.6% with AAT. Coverage of AXDX was 75.3%, specificity 99.7%, positive predictive value (PPV) 96.0%, and negative predictive value (NPV) 97.6%. On-panel sensitivity was 91.5%, specificity 99.6%, PPV 96.0%, and NPV 99.0%., Conclusions: AXDX provides more rapid ID and AST for GNB and ID for yeast than SOC. AXDX could potentially reduce time to AAT and facilitate ADE., (© 2018 American Association for Clinical Chemistry.)

Bacteremia and sepsis are critically important syndromes with high mortality, morbidity, and associated costs. Bloodstream infections and sepsis are among the top causes of mortality in the US, with >600 deaths each day. Most septic patients can be found in emergency medicine departments or critical care units, settings in which rapid administration of targeted antibiotic therapy can reduce mortality. Unfortunately, routine blood cultures are not rapid enough to aid in the decision of therapeutic intervention at the onset of bacteremia. As a result, empiric, broad-spectrum treatment is common-a costly approach that may fail to target the correct microbe effectively, may inadvertently harm patients via antimicrobial toxicity, and may contribute to the evolution of drug-resistant microbes. To overcome these challenges, laboratorians must understand the complexity of diagnosing and treating septic patients, focus on creating algorithms that rapidly support decisions for targeted antibiotic therapy, and synergize with existing emergency department and critical care clinical practices put forth in the Surviving Sepsis Guidelines., (© 2018 American Association for Clinical Chemistry.)

Objective: To report our experience using conventional culture methods (CM) and pediatric blood culture bottles (PBCBs) for vitreous sample culture of acute postoperative endophthalmitis., Methods: A retrospective study was conducted at the Department of Ophthalmology, Hospital das Clinicas, HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, BR, from January 2010 to December 2015, and it included 54 patients with clinically suspected acute postoperative endophthalmitis. Vitreous samples were obtained by vitreous tap or vitrectomy. Samples from January 2010 to December 2011 were cultivated in CM, whereas samples from January 2012 to December 2015 were inoculated in PBCBs. The measured outcome was the yield of positive cultures., Results: Twenty cases were included in the CM group, and 34 cases were included in the PBCB group. The yield of positive cultures in PBCBs (64.7%) was significantly higher than that in conventional CM (35%, p=0.034). Staphylococcus epidermidis and Streptococcus viridans were the two most commonly found agents., Conclusion: PBCBs can be used successfully in clinically suspected endophthalmitis. The method showed a higher yield of positive cultures than the conventional method. This technique appears to have several advantages over the traditional method: it saves time, as only one medium needs to be inoculated; transportation to a laboratory is easier than in the traditional method, and there is no need to maintain a supply of fresh agar media. The use of PBCBs may be recommended as the primary method for microbiological diagnosis and is especially suitable for office settings and remote clinics.

Fast diagnosis of pathogens is critical to guarantee the most adequate therapy for infections; bacterial culture methods, which constitute the actual gold standard, are precise and sensitive but rather slow. Today, new methods have been made available to enable faster diagnosis, with the Matrix-Assisted Laser Desorption Ionization-Time Of Flight Mass Spectrometry (MALDI-TOF MS) technique being the most promising. Even if simpler and faster than traditional bacterial culture methods, analysis of positive blood cultures via MALDI-TOF MS requires a preliminary extraction process of samples. In this study, we compared two extraction protocols for bacterial identification directly from positive blood cultures using the Bruker MALDI Biotyper system (Bruker Daltonics, Billerica, MA). In particular, we evaluated the time employed and the overall performance for their accurate identification. In this work, the performances of a commercial extraction kit, named SepsiTyper™ Kit, and those of the protocol developed by Treibmann et al. were evaluated and proven to be similar. However, the SELTERS method represents the best compromise price/performance. Lastly, an in-house developed analysis protocol has been tested, and the introduced optimizations granted a performance level equal if not better than the SepsiTyper kit, a reduced processing time and reduced costs., (Copyright © 2018 Elsevier B.V. All rights reserved.)

We report a case of bloodstream infection with the anaerobic bacterium Ruminococcus gnavus (R. gnavus), associated with intestinal perforation in a patient undergoing chemotherapy for multiple myeloma and cancer of the sigmoid colon. Gram staining of positive anaerobic blood cultures revealed both diplococci and short chains of gram-positive cocci. MALDI-TOF MS done directly on the blood culture bottle identified the bacterium as R. gnavus, and 16S rRNA gene sequencing confirmed the identification., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Rapid detection and identification of anaerobic bacteria from blood is important to adjust antimicrobial therapy by including antibiotics with activity against anaerobic bacteria. Limited data is available about direct identification of anaerobes from positive blood culture bottles using MALDI-TOF mass spectrometry (MS). In this study, we evaluated the performance of two sample preparation protocols for direct identification of anaerobes from positive blood culture bottles, the MALDI Sepsityper kit (Sepsityper) and the in-house saponin (saponin) method. Additionally, we compared two blood culture bottle types designed to support the growth of anaerobic bacteria, the BacT/ALERT-FN Plus (FN Plus) and the BACTEC-Lytic (Lytic), and their influence on direct identification. A selection of 30 anaerobe strains belonging to 22 different anaerobic species (11 reference strains and 19 clinical isolates) were inoculated to 2 blood culture bottle types in duplicate. In total, 120 bottles were inoculated and 99.2% (n = 119) signalled growth within 5 days of incubation. The Sepsityper method correctly identified 56.3% (n = 67) of anaerobes, while the saponin method correctly identified 84.9% (n = 101) of anaerobes with at least log(score) ≥1.6 (low confidence correct identification), (p < 0.001). Gram negative anaerobes were better identified with the saponin method (100% vs. 46.5%; p < 0.001), while Gram positive anaerobes were better identified with the Sepsityper method (70.8% vs. 62.5%; p = 0.454). Average log(score) values among only those isolates that were correctly identified simultaneously by both sample preparation methods were 2.119 and 2.029 in favour of the Sepsityper method, (p = 0.019). The inoculated bottle type didn't influence the performance of the two sample preparation methods. We confirmed that direct identification from positive blood culture bottles with MALDI-TOF MS is reliable for anaerobic bacteria. However, the results are influenced by the sample preparation method used., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Purpose: Bloodstream infections are major causes of morbidity and mortality that lead to prolonged hospital stays and higher medical costs. In this study, we aimed to evaluate the MinION nanopore sequencer for the identification of the most dominant pathogens in positive blood culture bottles., Methodology: 16S and ITS1-5.8S-ITS2 rRNA genes were amplified by PCR reactions with barcoded primers using nine clinical isolates obtained from positive blood bottles and 11 type strains, including five types of Candida species. Barcoded amplicons were mixed, and multiplex sequencing with the MinION sequencer was performed. In addition, barcoded PCR amplicons were sequenced by Sanger sequencing to validate the performance of the MinION., Results: The bacterial and Candida spp. identified by MinION sequencing, based on the highest homology of reference sequences from the NCBI gene databases, agreed with the matrix-assisted laser desorption ionization time of flight mass spectrometry results, excepting the closely related species Streptococcusand Escherichia coli. The 'pass' reads obtained within about 10 min of sequencing were sufficient to identify the pathogens. The average values of sequence identities with 1D 2 chemistry and the R9.5 flow cell were around 99 %; thus, frequent sequence errors did not affect species identification based on amplicon sequencing., Conclusion: We have established a rapid, portable and economical technique for the identification of pathogens in positive blood culture bottles through a novel MinION nanopore sequencer amplicon sequencing scheme, which replaces traditional Sanger sequencing.

Collecting adequate volumes of blood in blood culture bottles is crucial for sensitive detection of bacteremia and fungemia. Tools enabling easy collection of data on the degree of blood culture bottle filling at different hospital departments are an important step toward quality measurement and improvement. In this study, we verified the accuracy of a software tool for the monitoring of blood culture bottle filling developed by Becton Dickinson, BD blood volume monitoring system (BVMS) that was adjusted for use on plastic BACTEC bottles, and evaluated its ease of use in routine practice. In total, 538 negative plastic BD BACTEC Plus Aerobic/F blood culture bottles collected in two secondary care hospitals in Belgium were included in the study. The BVMS software demonstrated good performance, with an acceptable mean difference of - 0.3 mL or - 4.0% between the mean volume estimated by BVMS and the mean weight-based volume. Data (mean blood volume and standard deviation) and figures (box-and-whisker and histogram plots) on blood culture bottle filling are easily acquired. They provide information on the current situation in a hospital (department) and can be used as a tool for quality improvement measurements and follow-up. Caution is required when interpreting BVMS results for hospital wards where a substantial amount of the bottles collected come from patients with hematocrit values < 30%. This study demonstrated that BVMS is a reliable and easy to use tool which facilitates monitoring and coordination of optimization of blood culture bottles filling by the clinical laboratory.

Objective: To describe how frequently blood cultures (BCs) are obtained in the ED and to describe the incidence of true- and false-positive BC results., Methods: Retrospective descriptive study of all patients presenting to a tertiary-level, mixed Australian ED over a 15 month period., Results: A total of 3617 (3.67%) patients had BCs collected. Around one (12.1%) in eight of these BCs were positive; nearly half (45.2%) of which were identified as a false positive., Conclusions: BCs are a common investigation in the ED with a high false-positive rate. Strategies are required to reduce false positives, including reducing inappropriate collection and improving collection techniques., (© 2018 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.)

Rapid diagnostic tests are needed to improve patient care and to combat the problem of antimicrobial resistance. The Accelerate Pheno system (Accelerate Diagnostics, Tucson, AZ) is a new diagnostic device that can provide rapid bacterial identification and antimicrobial susceptibility test (AST) results directly from a positive blood culture. The device was compared to the standard of care at two academic medical centers. There were 298 blood cultures included in the study, and the Accelerate Pheno system provided a definitive identification result in 218 instances (73.2%). The Accelerate Pheno system provided a definitive and correct result for 173 runs (58.1%). The Accelerate Pheno system demonstrated an overall sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 94.7%, 98.9%, 83.7%, and 99.7%, respectively. An AST result was available for analysis in 146 instances. The overall category agreement was 94.1% with 12 very major errors, 5 major errors, and 55 minor errors. After a discrepancy analysis, there were 5 very major errors and 4 major errors. The Accelerate Pheno system provided an identification result in 1.4 h and an AST result in 6.6 h; the identification and AST results were 41.5 h and 48.4 h faster than those with the standard of care, respectively. This study demonstrated that the Accelerate Pheno system is able to provide fast and accurate organism identification and AST data. A limitation is the frequency with which cultures required the use of alternative identification and AST methods., (Copyright © 2018 American Society for Microbiology.)