654. Performance of the T2Resistance Panel in Detecting Antibiotic Resistant Bacteria Directly in Whole Blood, and Implications for Improving Appropriate Therapy of Bloodstream Infections

Abstract Background Appropriate antibiotic (Ab) therapy of bloodstream infections (BSI) is often delayed by time to blood culture (BC) positivity, species (sp) identification and Ab sensitivity (sensi). The T2Resistance (T2R) Panel is a direct-from-blood (culture-independent) diagnostic that detects 13 genetic markers associated with methicillin-resistant S. aureus (MRSA), vancomycin-resistant Enterococcus (VRE), ESBL- and carbapenemase-producing Enterobacteriaceae (E). We assessed T2R performance in detecting these resistant bacteria in whole blood (WB) and analyzed possible impact on time to appropriate Ab. Methods We performed T2R using WB samples obtained from patients (pts) on the same day as BCs from July 2019-2020. Receipt of appropriate Ab was assessed at time of empiric, Gram stain-directed, MALDI-directed (sp identification) and sensi-directed therapy. T2R results were not available to care teams. Teams were notified of positive BCs. Stewardship optimized Abs based on sensi. Results BC from 103 pts grew 114 bacterial sp: E (n=54; 16 ESBL-, 1 KPC-producer), S. aureus (n=29, 22 MRSA), Enterococcus (n=21, 16 VRE), P. aeruginosa and others (n=10). 12 ESBL-E produced CTX-M 14/15. T2R sensitivity and specificity was 78% and 99%, respectively, compared to sequencing of resistance markers. Sensitivity was excellent for vanA/B, KPC (100% each), and CTX-M14/15 (92%); sensitivity was 58% for mecA/C. T2R detected resistance determinants in 3-7h. Median time to appropriate Ab was 16.3h, which was significantly longer for VRE (25.6h) and ESBL- or KPC-E (50.9h) BSIs than for T2R marker-negative bacteria (6.7h; p=0.04). Pts with VRE or ESBL-/KPC-E BSI were less likely to received appropriate empiric Ab (18% and 30%, respectively) than pts with T2R marker-negative BSI (63%; p=0.02; Fig.1). Median times to achieve ≥80% appropriate Ab therapy of marker-negative, VRE and CTX-M/KPC-E BSIs were 15.5h (after Gram stain), 43.9h (after MALDI) and 63.5h (after sensi), respectively. Antibiotic Therapy Conclusion There was a significant delay in appropriate Ab therapy of BSIs, especially in pts infected with VRE and ESBL/KPC-E. T2R rapidly and accurately detected BSI caused by VRE and ESBL/KPC-E, and has the potential to significantly shorten time to appropriate Ab. Disclosures Cornelius J. Clancy, MD, Merck (Grant/Research Support) Ryan K. Shields, PharmD, MS, Shionogi (Consultant, Research Grant or Support) Minh-Hong Nguyen, MD, Merck (Grant/Research Support)

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Detection of Carbapenem-Resistant Enterobacterales in Simulated Blood Culture in 15 Minutes

Life ◽

10.3390/life11020145 ◽

2021 ◽

Vol 11 (2) ◽

pp. 145

Author(s):

Daria Baer ◽

Maya Azrad ◽

Nora Saleh ◽

Avi Peretz

Keyword(s):

Blood Culture ◽

Medical Center ◽

Bloodstream Infections ◽

Resistant Bacteria ◽

Clinical Microbiology Laboratory ◽

Antibiotic Resistant ◽

Culture Bottle ◽

Carbapenem Resistant ◽

Life Threatening ◽

Threatening Situation

Bacteremia leading to sepsis and organ dysfunction is a life-threatening situation, leading to death of up to one fourth of the infected individuals around the world. One major challenge in the treatment of sepsis is the rising prevalence of antibiotic resistant bacteria, such as carbapenem-resistant Enterobacterales (CRE). In recent years, several molecular assays have been developed for the detection of CRE mechanisms, enabling rapid results reporting. We evaluated the performance of the NG-Test CARBA 5 (NG Biotech) kit in detection of CRE in simulated blood cultures. Carbapenemase-producing (CP) CRE isolates (n = 38) and non-carbapenemase CRE (Non-CP) isolates (n = 10), previously identified using the routine methods practiced at the clinical microbiology laboratory of the Baruch Padeh Medical Center, Israel, were used in this analysis. Variable concentrations of the bacterial isolates were added to a suspension composed of human blood and saline, simulating the composition of a blood culture. Samples were then transferred to an anaerobic blood culture bottle and later tested with the NG-Test CARBA 5 (NG Biotech) kit, that identifies the CRE mechanism within 15 min. The NG-Test CARBA 5 kit correctly identified 43 samples (89.5%). The sensitivity and specificity of the kits were 86.8% and 100%, respectively. In conclusion, the NG-Test CARBA 5 kit is a reliable and accessible tool for the rapid diagnosis of CRE bloodstream infections.

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Detection of carbapenemase-resistant Enterobacterales in blood culture in 15 minutes

10.21203/rs.2.23537/v1 ◽

2020 ◽

Author(s):

Daria Baer ◽

Maya Azrad ◽

Nora Saleh ◽

Avi Peretz

Keyword(s):

Blood Culture ◽

Medical Center ◽

Bloodstream Infections ◽

Resistant Bacteria ◽

Clinical Microbiology Laboratory ◽

Antibiotic Resistant ◽

Culture Bottle ◽

Carbapenem Resistant ◽

Life Threatening ◽

Threatening Situation

Abstract Background: Bacteremia leading to sepsis and organ dysfunction is a life-threatening situation. One major challenge in treatment of sepsis is the uprising prevalence of antibiotic resistant bacteria, such as Carbapenem-resistant Enterobacterales (CRE). In recent years several molecular assays have been developed for the detection of CRE mechanisms, enabling rapid results reporting. We evaluated the performance of NG-Test CARBA 5 (NG Biotech) kit for detection of CRE, directly from patients’ blood culture.Methods: Carbapenemase-producing (CP) CRE-positive isolates (n=38) and non-carbapenemase CRE (non-CP) isolates (n=10), previously identified using the routine methods practiced at the clinical microbiology laboratory of the Baruch Padeh Medical Center, Israel were used in this analysis. Variable concentrations of the bacterial isolates were added to a suspension composed of blood unit and saline simulating the composition of a blood culture. Samples were then transferred to an anaerobic blood culture bottle and later tested it with the NG-Test CARBA 5 (NG Biotech) kit, that identifies the CRE mechanism in 15 minutes.Results: The NG-Test CARBA 5 kit correctly identified 43 samples (89.5%). The sensitivity and specificity of the kit were 86.8% and 100%, respectively.Conclusions: The NG-Test CARBA 5 kit is a reliable and accessible tool for the rapid diagnosis of CRE bloodstream infections.

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Substantial diagnostic impact of blood culture independent molecular methods in bloodstream infections: Superior performance of PCR/ESI-MS

Scientific Reports ◽

10.1038/s41598-018-34298-7 ◽

2018 ◽

Vol 8 (1) ◽

Cited By ~ 7

Author(s):

Athanasios Makristathis ◽

Nicole Harrison ◽

Franz Ratzinger ◽

Manuel Kussmann ◽

Brigitte Selitsch ◽

...

Keyword(s):

Blood Culture ◽

Bloodstream Infections ◽

Molecular Methods ◽

Superior Performance ◽

Diagnostic Impact ◽

Esi Ms ◽

Culture Independent

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Clinical Evaluation of the iCubate iC-GPC Assay for Detection of Gram-Positive Bacteria and Resistance Markers from Positive Blood Cultures

Journal of Clinical Microbiology ◽

10.1128/jcm.00485-18 ◽

2018 ◽

Vol 56 (9) ◽

Cited By ~ 5

Author(s):

Paul A. Granato ◽

Melissa M. Unz ◽

Raymond H. Widen ◽

Suzane Silbert ◽

Stephen Young ◽

...

Keyword(s):

Blood Culture ◽

Staphylococcus Epidermidis ◽

Bloodstream Infections ◽

Blood Cultures ◽

Gram Positive ◽

Content Type ◽

Gram Positive Bacteria ◽

Sequencing Method ◽

Resistance Markers ◽

Gram Positive Cocci

ABSTRACT The iC-GPC Assay (iCubate, Huntsville, AL) is a qualitative multiplex test for the detection of five of the most common Gram-positive bacteria (Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, Enterococcus faecalis, and Enterococcus faecium) responsible for bacterial bloodstream infections, performed directly from positive blood cultures. The assay also detects the presence of the mecA, vanA, and vanB resistance determinants. This study comparatively evaluated the performance of the iC-GPC Assay against the Verigene Gram-positive blood culture (BC-GP) assay (Luminex Corp., Austin, TX) for 1,134 patient blood culture specimens positive for Gram-positive cocci. The iC-GPC Assay had an overall percent agreement with the BC-GP assay of 95.5%. Discordant specimens were further analyzed by PCR and a bidirectional sequencing method. The results indicate that the iC-GPC Assay together with the iCubate system is an accurate and reliable tool for the detection of the five most common Gram-positive bacteria and their resistance markers responsible for bloodstream infections.

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Impact of Baseline Characteristics on Future Episodes of Bloodstream Infections: Multistate Model in Septic Patients With Bloodstream Infections

Clinical Infectious Diseases ◽

10.1093/cid/ciz1206 ◽

2019 ◽

Author(s):

M Cristina Vazquez Guillamet ◽

Rodrigo Vazquez ◽

Jonas Noe ◽

Scott T Micek ◽

Victoria J Fraser ◽

...

Keyword(s):

Risk Factors ◽

Blood Culture ◽

Bloodstream Infections ◽

Baseline Risk ◽

Resistant Bacteria ◽

Beta Lactam ◽

Candida Spp ◽

Patients At Risk ◽

Baseline Characteristics ◽

Inappropriate Antibiotics

Abstract Background Looking only at the index infection, studies have described risk factors for infections caused by resistant bacteria. We hypothesized that septic patients with bloodstream infections may transition across states characterized by different microbiology and that their trajectory is not uniform. We also hypothesized that baseline risk factors may influence subsequent blood culture results. Methods All adult septic patients with positive blood cultures over a 7-year period were included in the study. Baseline risk factors were recorded. We followed all survivors longitudinally and recorded subsequent blood culture results. We separated states into bacteremia caused by gram-positive cocci, susceptible gram-negative bacilli (sGNB), resistant GNB (rGNB), and Candida spp. Detrimental transitions were considered when transitioning to a culture with a higher mortality risk (rGNB and Candida spp.). A multistate Markov-like model was used to determine risk factors associated with detrimental transitions. Results A total of 990 patients survived and experienced at least 1 transition, with a total of 4282 transitions. Inappropriate antibiotics, previous antibiotic exposure, and index bloodstream infection caused by either rGNB or Candida spp. were associated with detrimental transitions. Double antibiotic therapy (beta-lactam plus either an aminoglycoside or a fluoroquinolone) protected against detrimental transitions. Conclusion Baseline characteristics that include prescribed antibiotics can identify patients at risk for subsequent bloodstream infections caused by resistant bacteria. By altering the initial treatment, we could potentially influence future bacteremic states.

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Clinical Utility of Follow-up Urinary Gram-Stain for Pyelonephritis: A Retrospective Observational Study

10.21203/rs.3.rs-119706/v1 ◽

2020 ◽

Author(s):

Masafumi Abe ◽

Takeshi Ueda ◽

Satoshi Yoshikawa ◽

Kazusa Saegusa

Keyword(s):

Likelihood Ratio ◽

Clinical Utility ◽

Early Stage ◽

Positive Likelihood Ratio ◽

Negative Likelihood Ratio ◽

Resistant Bacteria ◽

Gram Stain ◽

Antibiotic Resistant ◽

The Mean

Abstract Background: The effectiveness of antibiotic therapy for the treatment of pyelonephritis is typically evaluated by the clinical course and results of urine culture. The purpose of this study was to evaluate the usefulness of follow-up urinary gram-stain. Methods: We analyzed the results of hospitalized pyelonephritis patients treated in our department during the last 6.5 years. We investigated whether follow-up urinary gram-stain within 48 hours after initiating antibiotic treatment can help predict resistance to antibiotics at an early stage. Results: 271 patients were enrolled in the study. The mean age was 84.1 years old, and 204 of them (72%) were female. the diagnostic accuracy of using follow-up gram-stain to predict the presence of antibiotic-resistant bacteria was as follows: sensitivity: 41%, specificity: 82%, positive likelihood ratio: 2.32, and negative likelihood ratio: 0.71. It was also shown that the presence of elongated cells can help predict resistant bacteria more accurately. Conclusions: Follow-up urinary gram-stain is considered useful on treating patients with pyelonephritis as it facilitates evaluation of antibiotic effectiveness at an early stage.

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Metagenomics-Guided Assessment of Water Quality and Predicting Pathogenic Load

10.4018/978-1-7998-9498-8.ch005 ◽

2022 ◽

pp. 71-91

Author(s):

Sayak Ganguli ◽

Rupsha Karmakar ◽

Meesha Singh ◽

Mahashweta Mitra Ghosh

Keyword(s):

Molecular Techniques ◽

Resistant Bacteria ◽

Load Prediction ◽

Antibiotic Resistant ◽

Comparative Metagenomics ◽

Tropical Environments ◽

Culture Independent ◽

Urban Sample ◽

Rural Sample ◽

Irritable Bowel

Antibiotic-resistant bacteria (ARB) are becoming more prevalent in the environment and are efficiently disseminating through contaminated wastewater resulting in resistome cycling. This chapter compares the bacterial profile of hospital effluents collected from rural, urban, and delta regions of West Bengal, India. Comparative metagenomics analysis identified pathogenic bacterial genera like pseudomonas, escherichia, staphylococcus, lactobacillus, prevotella, acinetobacter across the samples. Delta sample showed highest abundance of pseudomonas whereas rural sample had lower titre of all the common bacterial genera. Urban sample reflected more diversity of different genera in terms of abundance. Pathogenic load prediction revealed significant occurrence of diarrhea, irritable bowel syndrome, liver cirrhosis, ulcerative colitis in the disease network. This chapter proposes a monitoring programme for assessing wastewater health using a combination of culture independent and culture-dependent molecular techniques in order to prevent the spread of pollutants in tropical environments.

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11. Evaluation of the Bact/alert® VIRTUO™ in Terms of Time to Detection, Performance, Workflow Efficiency and Impact on Patient Management, Compared to the BACTEC™ FX Automated Blood Culture System

Open Forum Infectious Diseases ◽

10.1093/ofid/ofaa417.010 ◽

2020 ◽

Vol 7 (Supplement_1) ◽

pp. S7-S7

Author(s):

Ana V Halperin ◽

José Luis Cortés Cuevas ◽

Juan Antonio Del Castillo Polo ◽

Miriam Cuesta ◽

Sergio Talens ◽

...

Keyword(s):

Blood Culture ◽

Large Scale ◽

Clinical Performance ◽

Bloodstream Infections ◽

Blood Cultures ◽

Causative Organism ◽

Research Support ◽

Hands On ◽

Time To Detection ◽

Research Grant

Abstract Background Bloodstream infections are associated with high rates of morbidity and mortality, therefore prompt identification and antimicrobial susceptibility testing of the causative organism(s) are critical. We compared the microbiological/clinical performance of BacT/ALERT®-VIRTUO™-(BioMerieux) to that of the BACTEC™FX-(BD) instrument, with time-to-detection (TTD, from loading into system until positivity) as the primary outcome. Secondary microbiological outcomes were positivity and contamination rates, hands-on-time, turn-around-time (TAT) and time-to-identification. Methods We performed a prospective cross-over study using blood cultures from patients (>18 years) suspected of bacteremia/fungemia, localized in different wards into two strata (Stratum-1: Emergency Department-ED-; Stratum-2: in-hospital patients). Testing was performed in BACTEC™-PlusAerobic/F and BACTEC-Lytic/10-Anaerobic/F bottles and incubated in BACTEC™FX, or BacT/ALERT®FA-Plus and FN-Plus bottles and incubated in VIRTUO™. Initially, each strata was randomly assigned to one of the incubators and then alternated every 2-weeks for 6 months (October-16th-2018 to April-16th-2019). All samples were processed in parallel with the same work-flow from the moment they were flagged positive. Maximum incubation time was 5 days. Results We included a total of 4782 extractions (9510 bottles) in VIRTUO and 5139 (10193 bottles) in BACTEC. The median age was 67 years for both groups and the samples were equally distributed for each ward (ED: VIRTUO 80.9%, BD 76.4%). The number of blood cultures with at least one positive extraction was 873(18.3%) for VIRTUO and 802(15.6%) for BACTEC (p=0.0003). TTD and proportion of aerobic/anaerobic bottles is shown in Table. Hands-on-time was reduced by 15 minutes/day when using VIRTUO. Table Conclusion We have compared on a large scale and in a “real world” setting the performance of two automatic blood culture incubators. TTD was significantly lower for the VIRTUO incubated samples, with differences in both systems depending on the type of bottle (aerobic vs. anaerobic). The number of positive results was significantly higher for the VIRTUO incubated samples, which might impact antimicrobial prescription and clinical outcomes. Disclosures Ana V. Halperin, MD, Biomérieux (Grant/Research Support) José Luis Cortés Cuevas, MD, biomerieux (Research Grant or Support)biomerieux (Research Grant or Support) Juan Antonio Del Castillo Polo, MD, Biomérieux (Research Grant or Support) Sergio Talens, n/a, Biomerieux (Research Grant or Support) Robert Birch, n/a, bioMerieux Inc. (Employee) Rafael Cantón, PharmD PhD, Biomérieux (Grant/Research Support)

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1009. Venous 1: A Prospective Multicenter Cohort Study of Enterococcal Bacteremia

Open Forum Infectious Diseases ◽

10.1093/ofid/ofy210.846 ◽

2018 ◽

Vol 5 (suppl_1) ◽

pp. S300-S300

Author(s):

German Contreras ◽

Jose M Munita ◽

Katherine C Reyes ◽

Pranoti Sahasrabhojane ◽

Helina Misikir ◽

...

Keyword(s):

Blood Culture ◽

Hematological Malignancy ◽

Bloodstream Infections ◽

Marrow Transplant ◽

Research Support ◽

Multicenter Cohort Study ◽

Icu Admission ◽

Tertiary Hospitals ◽

A Prospective Study ◽

Enterococcal Bacteremia

Abstract Background Enterococci often cause hospital-associated bloodstream infections in critically ill and immunocompromised patients. Prospective studies to assess the clinical impact of enterococcal bacteremia (EB) are lacking. We conducted a prospective study to investigate the clinical and microbiological factors associated with mortality in EB. Methods Adults with EB were prospectively followed in three US tertiary hospitals from September 2016 to March 2018. Individuals with EB for whom follow-up blood culture data within 7 days of index culture were available were included. Microbiologic failure (MF) was defined as clearance of bacteremia ≥4 days after the first blood culture. The main outcome was hospital mortality. Results A total of 282 patients were included with 69 (24%) infected with vancomycin-resistant enterococci (VRE). The majority of patients were male (60%) with a median age of 63 years. Median length of hospitalization for VRE patients was longer (25 d) than non-VRE (13 days, P < 0.001). E. faecium corresponded to 77% of VRE isolates, whereas E. faecalis comprised 72% of non-VRE. The average time to first blood culture was 16 days for VRE vs. 4 days for non-VRE (P < 0.001). Patients with VRE were more likely to have hematological malignancy or bone marrow transplant (P < 0.003), whereas patients infected non-VRE were more likely to have solid tumors (P = 0.02). The most common antibiotic used was daptomycin as monotherapy for both VRE and non-VRE with a median dose of 8 mg/kg for both groups. Overall mortality was 25% (43% vs. 20% in VRE vs. non-VRE patients, respectively; P < 0.0001). Factors significantly associated with mortality in univariate analyses included ICU admission, prolonged hospitalization, hematological malignancy, use of immunosuppressive therapy, hemodialysis, neutropenia (<500 cell/mL), Pitt bacteremia score >3, infection with VRE and MF. ICU admission (RR 3.3; 95% CI 1.7–7.5, neutropenia (RR 4.1; 95% CI 1.3–12.9), Pitt bacteremia score >3 (RR 6.8; 95% CI 2.6–18.0), MF (RR 4.7; 95% CI 2.2–10.3) and infection with VRE (RR 4.1; 95% CI 1.1–16.6) remained significantly associated with mortality in multivariate analyses. Conclusion The presence of VRE in EB and MF are associated with increased mortality. EB represent a major burden of disease in hospital settings. Disclosures C. Arias, Merck & Co., Inc.: Grant Investigator, Research support. MeMed: Grant Investigator, Research support. Allergan: Grant Investigator, Research support.

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251. High prevalence of the cefazolin inoculum effect in methicillin-susceptible Staphylococcus aureus causing bloodstream infections in a hospital network in Houston, TX

Open Forum Infectious Diseases ◽

10.1093/ofid/ofaa439.295 ◽

2020 ◽

Vol 7 (Supplement_1) ◽

pp. S125-S125

Author(s):

Paulette M Pinargote-Cornejo ◽

Sara I Gomez-Villegas ◽

Alejandro De la Hoz ◽

William R Miller ◽

Claudia Pedroza ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Blood Culture ◽

Research Study ◽

Scientific Research ◽

Bloodstream Infections ◽

Research Support ◽

Study Investigator ◽

Definitive Therapy ◽

High Prevalence ◽

Inoculum Effect

Abstract Background Anti-staphylococcal β-lactams, such as anti-staphylococcal penicillins (AsPen) or cefazolin are the drugs of choice for methicillin-susceptible Staphylococcus aureus (MSSA) bloodstream infections. However, cefazolin has seen increasing use due to its better tolerance, lower cost, ease of administration and possibly better outcomes when compared to AsPen. Nevertheless, its efficacy may be compromised by the cefazolin inoculum effect (CzIE), defined as an increase in the minimum inhibitory concentration (MIC) of cefazolin to ≥16mg/L when a high inoculum (5x107 CFU/ml) is present. Previous studies have suggested that the prevalence of the CzIE varies geographically, with high prevalence in some Latin American countries. Prospective data evaluating the presence of the CzIE in deep-seated MSSA infections across the United States are lacking. Methods We performed a prospective observational study of MSSA bacteremia in a network of 13 hospitals in Houston, TX. Patients ≥ 18 years old, with a positive blood culture with MSSA, with at least one follow-up blood culture confirming clearance of the bacteremia, who received cefazolin or nafcillin as definitive therapy (72 hours or longer after culture results known) and whose original isolate was available for evaluation of the CzIE, were included. Patients with polymicrobial BSI, or those who received another antibiotic with activity against MSSA in the definitive therapy period were excluded. Cefazolin MICs were determined by broth microdilution at standard and high inoculum. Results We report the results of 50 patients enrolled from February 15, 2020-April 30, 2020. The baseline characteristics of each group are outlined in Table 1. A total of 37/50 (74%) received cefazolin as definitive therapy, and complicated bacteremia was seen in 27/50 (54%). A total of 16/50 (32%) of the MSSA isolates exhibited the CzIE. Two patients in our cohort died: both of whose isolates exhibited the CzIE and received cefazolin as definitive therapy. Conclusion We report a high prevalence of the CzIE in MSSA BSIs in a major US urban hospital network. Further evaluation of the clinical implications of the CzIE is urgently needed. Disclosures William R. Miller, MD, Entasis Therapeutics (Scientific Research Study Investigator)Merck (Grant/Research Support)Shionogi (Advisor or Review Panel member) Cesar A. Arias, MD, MSc, PhD, FIDSA, Entasis Therapeutics (Scientific Research Study Investigator) MeMed (Scientific Research Study Investigator) Merck (Grant/Research Support)

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