Clinical Utility of Blood Culture Identification 2 Panel in Flagged Blood Culture Samples from the Intensive Care Unit of a Tertiary Care Hospital.

Background: The availability of rapid diagnostic platforms for positive blood cultures has accelerated the speed at which the clinical microbiology laboratory can identify the causative organism and facilitate early appropriate antimicrobial therapy. There is a paucity of data regarding the clinical utility of the blood culture identification 2 (BCID2) panel test and its correlation with phenotypic drug susceptibility testing (DST) in flagged blood culture bottles from intensive care units (ICUs) in countries such as India, which have high rates of multidrug-resistant gram-negative bacteria (MDR-GNB). Materials and methods: We conducted a retrospective observational study in a tertiary care ICU on 200 patients above 18 years of age in whom a BCID2 test was ordered when blood cultures flagged positive. Results: We found 99% concordance between BCID2 and cultures in the identification of bacteria and yeasts and 96.5% concordance between phenotypic and genotypic DST. Furthermore, BCID2 was available about 1.5 days earlier than conventional ID and DST and played a key role in tailoring antimicrobials in 82.5% of the patients. Polymyxin-based therapy was discontinued earlier after an empiric dose in 138 patients (69%) based on BCID2 reports. Conclusion: In critically ill patients with monomicrobial bacteremia, BCID2 rapidly identifies bacteria and antimicrobial resistance (AMR) genes and is significantly faster than conventional culture and sensitivity testing. Antibiotics were escalated in more than a third of patients and de-escalated in almost a fifth on the same day. We recommend that all ICUs routinely incorporate the test in their antibiotic decision-making process and in antimicrobial stewardship. How to cite this article: Vineeth VK, Nambi PS, Gopalakrishnan R, Sethuraman N, Ramanathan Y, Chandran C, et al. Clinical Utility of Blood Culture Identification 2 Panel in Flagged Blood Culture Samples from the Intensive Care Unit of a Tertiary Care Hospital. Indian J Crit Care Med 2024;28(5):461-466.

Etiological diagnostic performance of probe capture-based targeted next-generation sequencing in bloodstream infection.

Background: A rapid and precise etiological diagnosis is crucial for the effective treatment of bloodstream infection (BSI). In this study, the performance of probe capture-based targeted next-generation sequencing (tNGS) was compared to that of blood culture and metagenomic next-generation sequencing (mNGS) in detecting potential pathogens in patients with BSI. Methods: A total of 80 patients with suspected BSI were prospectively enrolled from 24 November 2023 to 30 December 2023 at Zhongshan Hospital, Shanghai, China. All 80 participants underwent simultaneous blood culture, blood mNGS, and blood tNGS after admission when febrile, and the results were compared. Results: Among the 80 participants, 11 were clinically diagnosed with noninfectious fever, and 69 were diagnosed with BSI. Blood tNGS had a higher sensitivity for the diagnosis of BSI than blood culture (91.3% vs. 23.2%, P<0.001) and blood mNGS (91.3% vs. 69.6%, P=0.001). There was no significant difference in specificity between blood mNGS and tNGS (81.8% vs. 100.0%, P=0.13). Blood tNGS demonstrated a faster turnaround time than blood culture and blood mNGS. In 22 (31.9%) patients with BSI, targeted adjustment of the anti-infectious therapy according to the blood tNGS results resulted in clinical improvement. Conclusions: Blood tNGS may be a promising tool for detecting potential pathogens in patients with BSI. The application of blood tNGS for BSI could guide anti-infectious treatment strategies and might improve clinical outcomes.

Rapid colorimetric polymyxin B microelution directly from positive blood bottles: because patients with serious infections should not have to wait for results of culture-based methodologies.

PURPOSE: To evaluate the performance of the rapid colorimetric polymyxin B microelution (RCPEm) in determining polymyxin B resistance directly from Enterobacterales-positive blood cultures. METHODS: A set volume of positive blood culture bottles (diluted 1:10) was inoculated into a glucose-broth-phenol red solution (NP solution), where a polymyxin B disk was previously eluted (final concentration of 3 µg/mL). Test was read each 1 h for up to 4 h. Color change from red/orange to yellow indicated resistant isolates. Results were compared to the reference method, broth microdilution (BMD), performed from colonies grown on solid media from the same blood culture bottle. RESULTS: One hundred fifty-two Enterobacterales-positive blood cultures were evaluated, 22.4% (34/152) of them resistant to polymyxin B (including 6.6% with borderline MICs). When performing directly from positive blood cultures (RCPEm-BC), specificity and sensitivity were 99.1% and 94.1%, respectively. Of note, 79.4% (27/34) of truly resistant isolates required 3 h of incubation, compared to the 18 ± 2 h incubation that microtiter plates of BMD demand before reading can be performed. CONCLUSIONS: RCPEm directly from blood cultures has great potential to be part of the routine of clinical microbiology laboratories to establish polymyxin B susceptibility, impacting outcome of patients with bloodstream infections caused by carbapenem-resistant Enterobacterales.

Microbiology of bloodstream infections in Ontario, Canada during COVID-19 pandemic.

Background: Bloodstream infections (BSI) caused by a wide range of bacterial and fungal pathogens are associated with high rates of morbidity and mortality. Based on an estimate in 2017, the number of BSI incidences in Ontario is 150 per 100,000 population. The epidemiology of BSIs may be affected by many factors, including the social and travel restrictions and increased rates of hospitalizations in Ontario during the coronavirus disease 2019 (COVID-19) pandemic. Objectives: This study aimed to assess the changes in the microbiology of BSIs in Ontario during the COVID-19 pandemic compared to the pre-pandemic period. Methods: Retrospective blood culture data (n=189,106) from LifeLabs Ontario (July 2018 to December 2021) were analyzed. Blood culture positivity rates for common bacterial pathogens were compared between pre-COVID-19 (July 2018 to March 2020) and COVID-19 (April 2020 to December 2021) periods in community and hospital settings, using the chi-square test for significance. Results: During the COVID-19 period, blood culture positivity rates in the community remained the same, while hospital rates increased by approximately threefold (p=0.00E-00). In the community, the isolation rates of most bacterial species remained unchanged, except for an increase in Enterococcus spp. and a decrease in Salmonella spp. The rates of antibiotic-resistant organisms (AROs) also significantly decreased in the community. In hospitals, all bacterial species, including AROs, showed significant increases in isolation rates during the COVID-19 period. Conclusion: The study revealed shifts in the microbiology of BSIs and suggests changes in the epidemiology of BSIs during the COVID-19 pandemic in Ontario, both in hospitals and in the community.

Should Blood Cultures Be Drawn Through an Indwelling Catheter?

There is no practical way to definitively diagnose a catheter-related bloodstream infection in situ if blood cultures are only obtained percutaneously unless there is the rare occurrence of purulent drainage from a central venous catheter insertion site. That is why the Infectious Diseases Society of America guidelines for diagnosis and management of catheter-related bloodstream infections and Infectious Diseases Society of America guidelines for evaluation of fever in critically ill patients both recommend drawing blood cultures from a central venous catheter and percutaneously if the catheter is a suspected source of infection. However, central venous catheter-drawn blood cultures may be more likely to be positive reflecting catheter hub, connector, or intraluminal colonization, and many hospitals in the United States discourage blood culture collection from catheters in an effort to reduce reporting of central-line associated bloodstream infections to the Centers for Disease Control and Prevention. As such, clinical decisions are made regarding catheter removal or other therapeutic interventions based on incomplete and potentially inaccurate data. We urge clinicians to obtain catheter-drawn blood cultures when the catheter may be the source of suspected infection.

Sensitive and rapid identification of pathogens by droplet digital PCR in a cohort of septic patients: a prospective diagnostic study.

BACKGROUND: There is a critical need for a rapid and sensitive pathogen detection method for septic patients. This study aimed to investigate the diagnostic efficacy of Digital droplet polymerase chain reaction (ddPCR) in identifying pathogens among suspected septic patients. METHODS: We conducted a prospective pilot diagnostic study to clinically validate the multiplex ddPCR panel in diagnosing suspected septic patients. A total of 100 sepsis episodes of 89 patients were included in the study. RESULTS: In comparison to blood culture, the ddPCR panel exhibited an overall sensitivity of 75.0% and a specificity of 69.7%, ddPCR yielded an additional detection rate of 17.0% for sepsis cases overall, with a turnaround time of 2.5 h. The sensitivity of ddPCR in the empirical antibiotic treatment and the non-empirical antibiotic treatment group were 78.6% versus 80.0% (p > 0.05). Antimicrobial resistance genes were identified in a total of 13 samples. Whenever ddPCR detected the genes beta-lactamase-Klebsiella pneumoniae carbapenemase (blaKPC) or beta-lactamase-New Delhi metallo (blaNDM), these findings corresponded to the cultivation of carbapenem-resistant gram-negative bacteria. Dynamic ddPCR monitoring revealed a consistent alignment between the quantitative ddPCR results and the trends observed in C-reactive protein and procalcitonin levels. CONCLUSIONS: Compared to blood culture, ddPCR exhibited higher sensitivity for pathogen diagnosis in suspected septic patients, and it provided pathogen and drug resistance information in a shorter time. The quantitative results of ddPCR generally aligned with the trends seen in C-reactive protein and procalcitonin levels, indicating that ddPCR can serve as a dynamic monitoring tool for pathogen load in septic patients.

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.

Rapid Direct Identification of Microbial Pathogens and Antimicrobial Resistance Genes in Positive Blood Cultures Using a Fully Automated Multiplex PCR Assay.

This study assessed the performance of the BioFire Blood Culture Identification 2 (BCID2) panel in identifying microorganisms and antimicrobial resistance (AMR) profiles in positive blood cultures (BCs) and its influence on turnaround time (TAT) compared with conventional culture methods. We obtained 117 positive BCs, of these, 102 (87.2%) were correctly identified using BCID2. The discordance was due to off-panel pathogens detected by culture (n = 13), and additional pathogens identified by BCID2 (n = 2). On-panel pathogen concordance between the conventional culture and BCID2 methods was 98.1% (102/104). The conventional method detected 19 carbapenemase-producing organisms, 14 extended-spectrum beta-lactamase-producing Enterobacterales, 18 methicillin-resistant Staphylococcus spp., and four vancomycin-resistant Enterococcus faecium. BCID2 correctly predicted 53 (96.4%) of 55 phenotypic resistance patterns by detecting AMR genes. The TAT for BCID2 was significantly lower than that for the conventional method. BCID2 rapidly identifies pathogens and AMR genes in positive BCs.

Blood Culture Algorithm Implementation in Emergency Department Patients as a Diagnostic Stewardship Intervention.

OBJECTIVE: Blood cultures (BCx) are important for selecting appropriate antibiotic treatment. Ordering BCx for conditions with a low probability of bacteremia has limited utility, thus improved guidance for ordering BCx is needed. Inpatient studies have implemented BCx algorithms, but no studies examine the intervention in an Emergency Department (ED) setting. METHODS: We performed a quasi-experimental pre-/post-intervention study from 12/1/2020 to 10/31/2023 at a single academic adult ED and implemented a BCx algorithm. The primary outcome was the blood culture event rates (BCE per 100 ED admissions) pre- and post-intervention. Secondary outcomes included adverse event rates (30-day ED and hospital readmission and antibiotic days of therapy). Seven ED physicians/APP reviewed BCx for appropriateness, with monthly feedback provided to ED leadership and physicians. RESULTS: After BCx algorithm implementation, the BCE rate decreased from 12.17 BCE/100 ED admissions to 10.50 BCE/100 ED admissions. Of the 3,478 reviewed BCE, we adjudicated 2153 BCE (62%) as appropriate, 653 (19%) as inappropriate, and 672 (19%) as uncertain. Adverse safety events were not statistically different pre/post-intervention. CONCLUSION: Implementation of an ED BCx algorithm demonstrated a reduction in BCE, without increased adverse safety events. Future studies should compare outcomes of BCx algorithm implementation in a community hospital ED without intensive chart review.

Rapid screening of positive blood cultures for extended-spectrum ß-lactamases and metallo-ß-lactamases using a drug susceptibility testing microfluidic method.

OBJECTIVES: An increasing number of drug-resistant bacteria have been identified recently. In particular, drug-resistant bacteria have been linked to unfavorable prognoses in patients with bacteremia, highlighting the need for rapid testing. Our previous studies have focused on the utility of a drug susceptibility testing microfluidic (DSTM) method using microfluidic channels. A system with this DSTM method for screening for ß-lactamases can rapidly detect extended-spectrum ß-lactamases (ESBLs) and metallo-ß-lactamases (MBLs). In this study, we have evaluated the clinical utility of pre-treatment for screening positive blood cultures using the DSTM method. METHODS: A total of 178 positive blood cultures and five simulated samples of MBL-producing bacteria were prepared at Kochi University Hospital, Japan. The pretreatment consisted of a two-step centrifugation. The obtained sediments were screened with the DSTM method for the production of ß-lactamase based on morphological changes in the bacteria after 3 h of incubation. RESULTS: The pretreatment functioned properly for all samples. Of the 25 ESBL samples, 21 were positive for ESBLs. Four false-negative samples, all obtained from the same patient, contained CTX-M-2 enzyme-producing Proteus mirabilis and showed insusceptibility to an ESBL inhibitor. The simulated samples prepared for MBL screening were positive for MBLs. CONCLUSIONS: When combined with a method for rapidly identifying bacterial species, DSTM may enable patients with bloodstream infections to start receiving appropriate treatment within 4 h after positive blood cultures are screened.

Enhancing pneumonia prognosis in the emergency department: a novel machine learning approach using complete blood count and differential leukocyte count combined with CURB-65 score.

BACKGROUND: Pneumonia poses a major global health challenge, necessitating accurate severity assessment tools. However, conventional scoring systems such as CURB-65 have inherent limitations. Machine learning (ML) offers a promising approach for prediction. We previously introduced the Blood Culture Prediction Index (BCPI) model, leveraging solely on complete blood count (CBC) and differential leukocyte count (DC), demonstrating its effectiveness in predicting bacteremia. Nevertheless, its potential in assessing pneumonia remains unexplored. Therefore, this study aims to compare the effectiveness of BCPI and CURB-65 in assessing pneumonia severity in an emergency department (ED) setting and develop an integrated ML model to enhance efficiency. METHODS: This retrospective study was conducted at a 3400-bed tertiary medical center in Taiwan. Data from 9,352 patients with pneumonia in the ED between 2019 and 2021 were analyzed in this study. We utilized the BCPI model, which was trained on CBC/DC data, and computed CURB-65 scores for each patient to compare their prognosis prediction capabilities. Subsequently, we developed a novel Cox regression model to predict in-hospital mortality, integrating the BCPI model and CURB-65 scores, aiming to assess whether this integration enhances predictive performance. RESULTS: The predictive performance of the BCPI model and CURB-65 score for the 30-day mortality rate in ED patients and the in-hospital mortality rate among admitted patients was comparable across all risk categories. However, the Cox regression model demonstrated an improved area under the ROC curve (AUC) of 0.713 than that of CURB-65 (0.668) for in-hospital mortality (p<0.001). In the lowest risk group (CURB-65=0), the Cox regression model outperformed CURB-65, with a significantly lower mortality rate (2.9% vs. 7.7%, p<0.001). CONCLUSIONS: The BCPI model, constructed using CBC/DC data and ML techniques, performs comparably to the widely utilized CURB-65 in predicting outcomes for patients with pneumonia in the ED. Furthermore, by integrating the CURB-65 score and BCPI model into a Cox regression model, we demonstrated improved prediction capabilities, particularly for low-risk patients. Given its simple parameters and easy training process, the Cox regression model may be a more effective prediction tool for classifying patients with pneumonia in the emergency room.

A Retrospective Observational Study of the Microbial Etiology and Antimicrobial Susceptibility Patterns of Blood Cultures From ICU Patients at a Healthcare Facility in North India.

Introduction Bloodstream infections (BSI) are a leading source of fatalities and morbidity in hospitals. However, the clinical spectrum and antimicrobial resistance differ globally. Identifying the pathogenic spectrum and variations in antibiotic resistance is crucial for controlling BSI and preventing inappropriate antibiotic use. Material and methods This retrospective observational study was conducted at the Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow, UP, India, for one year between June 2022 and June 2023. A total of 669 adult patients' blood cultures were obtained from ICUs. Blood culture was done using a BacT/Alert 3D (BioMérieux SA, Marcy-l'Étoile, France) automated system. Identification of the bacterial as well as fungal isolates was done using matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS), and the antimicrobial susceptibility profile was analyzed using the VITEK 2 Compact system (BioMérieux SA). Results Of the 669 blood culture samples, 213 (31.8%) showed bacterial or fungal growth. Of these 213 isolates, the most common isolate was coagulase-negative Staphylococci (21.6%), followed by Klebsiella pneumoniae (19.3%) and Acinetobacter spp. (17.8%). The majority of gram-negative bacteria were resistant to most drugs, and vancomycin and linezolid were both effective against the majority of gram-positive bacteria. Conclusion The current study found that septicemia was more frequently caused by gram-negative bacteria than by gram-positive bacteria. Blood cultures are always necessary in cases of suspected septicemia, and once the antimicrobial susceptibility profile of the pathogen causing septicemia has been determined, suitable antimicrobials should be prescribed and used to lower the antimicrobial resistance burden.

Proteomic assay for rapid characterisation of Staphylococcus aureus antimicrobial resistance mechanisms directly from blood cultures.

PURPOSE: Staphylococcus aureus is one of the most common pathogens causing bloodstream infection. A rapid characterisation of resistance to methicillin and, occasionally, to aminoglycosides for particular indications, is therefore crucial to quickly adapt the treatment and improve the clinical outcomes of septic patients. Among analytical technologies, targeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) has emerged as a promising tool to detect resistance mechanisms in clinical samples. METHODS: A rapid proteomic method was developed to detect and quantify the most clinically relevant antimicrobial resistance effectors in S. aureus in the context of sepsis: PBP2a, PBP2c, APH(3')-III, ANT(4')-I, and AAC(6')-APH(2''), directly from positive blood cultures and in less than 70 min including a 30-min cefoxitin-induction step. The method was tested on spiked blood culture bottles inoculated with 124 S.aureus, accounting for the known genomic diversity of SCCmec types and the genetic background of the strains. RESULTS: This method provided 99% agreement for PBP2a (n = 98/99 strains) detection. Agreement was 100% for PBP2c (n = 5/5), APH(3')-III (n = 16/16), and ANT(4')-I (n = 20/20), and 94% for AAC(6')-APH(2'') (n = 16/17). Across the entire strain collection, 100% negative agreement was reported for each of the 5 resistance proteins. Additionally, relative quantification of ANT(4')-I expression allowed to discriminate kanamycin-susceptible and -resistant strains, in all strains harbouring the ant(4')-Ia gene. CONCLUSION: The LC-MS/MS method presented herein demonstrates its ability to provide a reliable determination of S. aureus resistance mechanisms, directly from positive blood cultures and in a short turnaround time, as required in clinical laboratories.

Finding significant pathogens in blood cultures in children: Should we set the timer to 36 hours?

Background: Knowledge of time to positivity (TTP) for blood cultures is useful to assess timing of discontinuation of empiric antimicrobials for suspected bacteremia with no focus. Methods: An audit of positive blood cultures from the Children's Hospital of Eastern Ontario (CHEO) from November 1, 2019, to October 31, 2020, was performed to determine TTP, defined as the start of incubation to a positive signal from automated incubators. Results: Three hundred seventy-six positive blood cultures were identified from 248 patients (average age: 6.27 [SD 6.24] years). Of these, 247 isolates were speciated; 90 (36.4%) were definitive/probable (DP) pathogens (median TTP 12.75 hours) and 157 (63.6%) possible/probable (PP) contaminants (median TTP 24.08 hours). At each time point, the adjusted rate of positive blood culture was significantly higher for DP pathogens compared to PP contaminants (hazard ratio [HR] 1.80 [95% CI 1.37, 2.36]) and for children ≤27 days old compared to the oldest age group (HR 1.94 [95% CI 1.19, 3.17]). By 36 hours, the proportion of positive cultures was significantly higher in the youngest age group (≤27 days) compared with the 3-11 years old age group (91.7% [95% CI 68.6%, 97.8%] versus 58.2% [95% CI 46.91%, 68.06%]). Conclusion: Across all ages, the TTP was significantly shorter for blood cultures with DP pathogens compared to those with PP contaminants (HR 1.80 [95% CI 1.37, 2.36]). In newborns, 90% of blood cultures were positive by 36 hours supporting this re-assessment time for empiric antimicrobials. TTP was longer in children ≥12 months, possibly related to other factors such as blood culture volume.

Historique: Il est utile de connaître le délai de positivité (DdP) des hémocultures pour évaluer le moment de mettre un terme aux antimicrobiens empiriques en cas de présomption de bactériémie sans source apparente. Méthodologie: Les chercheurs ont procédé à un audit des hémocultures positives du Centre hospitalier pour enfants de l'est de l'Ontario (CHEO) entre le 1er novembre 2019 et le 31 octobre 2020 pour déterminer le DdP, défini comme la période entre le début de l'incubation et le signal positif d'incubateurs automatisés. Résultats: Les chercheurs ont extrait 376 hémocultures positives provenant de 248 patients (d'un âge moyen de 6,27 ± 6,24 ans). De ce nombre, ils ont différencié 247 isolats, dont 90 (36,4 %) étaient des agents pathogènes confirmés ou probables (CP) (DdP médian de 12,75 heures) et 157 (63,6 %), des contaminants possibles ou probables (PP) (DdP médian de 24,08 heures). À chaque point temporel, le taux corrigé d'hémocultures positives était sensiblement plus élevé à l'égard des agents pathogènes CP que des contaminants PP (rapport de risque instantanés [RRI] : 1,80 [IC à 95 % 1,37,2,36]) et des nouveau-nés de 27 jours de vie ou moins que des enfants plus âgés (RRI 1,94 [IC à 95 % 1,19,3,17]). Au bout de 36 heures, la proportion de cultures positives était sensiblement plus élevée dans le groupe le plus jeune (27 jours de vie ou moins) que dans celui des enfants de trois à 11 ans, soit de 91,7 % (IC à 95 % 68,6 %, 97,8 %) par rapport à 58,2 % (IC à 95 % 46,91 %, 68,06 %). Conclusion: À tout âge, le DdP était sensiblement plus court, à l'égard des hémocultures contenant des agents pathogènes CP que des contaminants PP (RRI 1,80 [IC à 95 % 1,37,2,36]). Chez les nouveau-nés, 90 % des hémocultures sont positives au bout de 36 heures, ce qui appuie ce moment pour réévaluer la prise d'antimicrobiens empiriques. Le DdP était plus long chez les enfants âgés de plus de 12 mois, peut-être à cause d'autres facteurs comme le volume de l'hémoculture.

Does it matter who performs blood culture collection? Results of a survey assessing phlebotomist, nurse, and resident knowledge of blood culture collection protocols.

Blood cultures are the primary method for diagnosing bloodstream infections. However, blood culture contamination (BCC) can lead to unnecessary antibiotic treatment, additional tests, and extended patient time in the hospital. The aim of this quality improvement project was to evaluate healthcare workers' knowledge of blood culture collection protocols and evaluate the blood culture contamination rates of laboratory and non-laboratory staff. We performed a retrospective review of contaminated cultures between May 2021 and April 2022, and anonymous surveys were distributed to assess staff knowledge of proper blood culture collection protocols. Laboratory staff (phlebotomy) had an overall BCC rate of 4.6% compared to a non-laboratory staff (nurses, residents, and medical students) rate of 9.7% (p < 0.0001). On the survey, phlebotomists had the best score (89% correct), followed by nurses (76%) and residents and medical students (64%). These data suggest that blood culture protocol knowledge and BCC rates may be related, with phlebotomists scoring highest on the knowledge survey and demonstrating the lowest contamination rates.

Evaluation of Direct Antimicrobial Susceptibility Testing from Positive Flagged Blood Cultures in Sepsis Patients.

Background: Presently, many laboratories are equipped with automated system for antimicrobial susceptibility testing (AST) for minimum inhibitory concentration-based reporting which enables the clinician to choose the right antimicrobial for timely treatment of sepsis. The study aimed to assess performance of direct AST from blood culture positive broth using automated AST system for accuracy and time taken to release the report. Materials and methods: The present study conducted in a 25-bedded ICU in North India for 12 months. Single morphotype of bacteria on gram stain from positively flagged blood culture bottles were included, which was directly identified (using an in-house protocol) with MALDI-TOF-MS from positive blood culture broths. DAST was carried out from 200 such blood culture broths and results were compared with reference AST (RAST) which was also done using VITEK-2 using overnight grown bacterial colonies as per standard protocol. Results: Among 60 isolates of Enterobacterales, 99% categorical agreement for both E. coli and K. pneumoniae observed by two methods were tested for AST. Among non-fermenters, Pseudomonas aeruginosa showed a categorical agreement of 99.6%, as compared with Acinetobacter spp. and exotic GNBs, which showed 95-96% agreement. A significant difference of 18-24 hours was noted in time to release the report between DAST and RAST, for GNB and GPC both. Conclusion: Direct AST from positive flagged blood culture bottles can significantly reduce the time to release the bacterial susceptibility report by up to 24 hours, at the same time maintaining the accuracy. How to cite this article: Singh V, Agarwal J, Nath SS, Sharma A. Evaluation of Direct Antimicrobial Susceptibility Testing from Positive Flagged Blood Cultures in Sepsis Patients. Indian J Crit Care Med 2024;28(4):387-392.

A Day Saved is a Life Saved: Direct Antimicrobial Susceptibility Testing from Positively Flagged Blood Culture Bottles and their Concordance with the Routine Method.

BACKGROUND: Sepsis is a major health problem worldwide and is associated with high morbidity and mortality with every hour delay in initiation of therapy. A conventional method of blood culture and Antimicrobial Susceptibility Testing (AST) takes around 48-72 hours. Empirical antibiotics need to be administered until the sensitivity report is made available. It has been estimated that 20-50% of the empirical antibiotics are inappropriate, resulting in prolonged hospital stays, adverse effects, and emergence of drug resistance. Additionally, this also puts an extra financial burden on both the patients and healthcare settings. Performing direct Antimicrobial Sensitivity Testing (dAST) is an important tool to reduce turn-around time (TAT) by at least 18-24 hours, thus reducing morbidity and mortality among critically ill patients. METHODS: Direct AST (dAST) was performed from the positively flagged blood culture bottles received between December, 2021 to May, 2022 from Intensive Care Units (ICUs) on MuellerHinton Agar (MHA) using four drops of withdrawn blood. dAST was performed for six drugs: Ceftriaxone-30 µg (CTR), Piperacillin/Tazobactam-100/10 µg (PIT), Meropenem-10 µg (MRP), Ciprofloxacin-5 µg (CIP), Aztreonam-30 µg (AT), and Colistin (CL). The zone of inhibition was interpreted as per CLSI M100 ed32, 2022 guidelines. A parallel conventional method was also performed to examine for categorical agreement and disagreement. Identification was carried out using MALDI-TOF MS from the colonies that appeared on the dAST plate on the subsequent day. RESULTS: A total of 162 positively flagged blood culture bottles were included in the study. The majority of the Gram-negative organisms were from Enterobacterales (n=109), followed by Acinetobacter spp. (n=28) and Pseudomonas aeruginosa (n=25). Out of the 972 isolate-antimicrobial combinations, overall Categorical Agreement (CA) was seen in 936 (96.3%), whereas disagreement was observed in 36 with minor error (mE) in 21 (2.2%), major error (ME) in 7 (0.7%), and very major error (VME) in 8 (0.8%) when compared to the routine method. Categorical agreement (CA) of > 99% was seen in ceftriaxone (CTR) and ciprofloxacin (CIP). In comparison, the lowest CA was observed with meropenem (MRP) at 92%. Colistin dAST was performed using the E-strip method, and the result obtained was highly convincing, with an overall disagreement of only 1.2%. CONCLUSION: Rapid dAST from positively flagged blood culture bottles proved to significantly reduce the TAT from the time of sample collection to the first availability of antimicrobial susceptibility report with excellent categorical agreement of > 95% using the conventional disc diffusion method. Results obtained were within the acceptance criteria set by U. S. Food and Drug Administration (FDA) guidelines of > 90% categorical agreement for a new method. We were able to obtain excellent concordance for colistin using the E-strip method. Performing dAST not only saves a "day", but its proper implementation would save a "life".

[Urosepsis: pathophysiology, diagnosis, and management-an update]. / Urosepsis: Pathophysiologie, Diagnose und Management ­ ein Update.

Urinary tract infections vary widely in their clinical spectrum, ranging from uncomplicated cystitis to septic shock. Urosepsis accounts for 9-31% of all cases of septicemia and is often associated with nosocomial infections. A major risk factor for urosepsis is the presence of obstructive uropathy, caused by conditions such as urolithiasis, tumors, or strictures. The severity and course of urosepsis depend on both the virulence of the pathogen and the patient's specific immune response. Prompt therapy, including antimicrobial treatment and eradication of the infection source, along with supportive measures for circulatory and respiratory stabilization, and adjunctive therapies such as hemodialysis and glucocorticoid therapy, is crucial. Due to demographic changes, an increase in cases of urosepsis is expected-thus, it is of utmost importance for urologists to be familiar with targeted diagnostics and effective treatment.