The smart activatable P2&3TT probe allows accurate, fast, and highly sensitive detection of Staphylococcus aureus in clinical blood culture samples

Abstract Staphylococcus aureus bacteraemia (SAB) is associated with high mortality and morbidity rates. Yet, there is currently no adequate diagnostic test for early and rapid diagnosis of SAB. Therefore, this study was aimed at exploring the potential for clinical implementation of a nuclease-activatable fluorescent probe for early diagnosis of SAB. To this end, clinical blood culture samples from patients with bloodstream infections were incubated for 1 h with the “smart” activatable P2&3TT probe, the total assay time being less than 2 h. Cleavage of this probe by the secreted S. aureus enzyme micrococcal nuclease results in emission of a readily detectable fluorescence signal. Incubation of S. aureus-positive blood culture samples with the P2&3TT probe resulted in 50-fold higher fluorescence intensity levels than incubation with culture-negative samples. Moreover, incubation of the probe with non-S. aureus-positive blood cultures yielded essentially background fluorescence intensity levels for cultures with Gram-negative bacteria, and only ~ 3.5-fold increased fluorescence intensity levels over background for cultures with non-S. aureus Gram-positive bacteria. Importantly, the measured fluorescence intensities were dose-dependent, and a positive signal was clearly detectable for S. aureus-positive blood cultures with bacterial loads as low as ~ 7,000 colony-forming units/mL. Thus, the nuclease-activatable P2&3TT probe distinguishes clinical S. aureus-positive blood cultures from non-S. aureus-positive blood cultures and culture-negative blood, accurately, rapidly and with high sensitivity. We conclude that this probe may enhance the diagnosis of SAB.

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Time to Grow Positive Blood Cultures and Its Impact on Clinical Outcomes in Patients with Bacteremia Admitted to Intensive Care Unit

Dubai Medical Journal ◽

10.1159/000513429 ◽

2021 ◽

pp. 1-6

Author(s):

Rashid Nadeem ◽

Ashraf M. Elhoufi ◽

Lamiaa Salama ◽

Mayada Mahmoud ◽

Islam Bon ◽

...

Keyword(s):

Length Of Stay ◽

Blood Culture ◽

Clinical Outcomes ◽

Severity Of Illness ◽

Bloodstream Infections ◽

Blood Cultures ◽

Comorbid Conditions ◽

Mortality And Morbidity ◽

Causes Of Mortality ◽

The Impact

Introduction: Bloodstream infections are one of the leading causes of mortality and morbidity. Time to positive blood culture may be reflective of the severity of infection. We aim to study the impact of time to positivity (TTP) of blood culture upon clinical outcome. Methods: Data from blood cultures for 17 months duration reviewed. Outcome measures included in-hospital mortality and length of stay in ICU (LOSICU). TTP was determined for each sample. Demographics (age, gender, BMI, and nationality), APACHE-2 score for severity of illness, comorbid conditions, and other confounding factors were recorded. Results: One hundred and one patients with 346 positive blood cultures with mean age of 62 and mean APACHE-2 score of 18.9 + 9.7 (mean +SD) with overall observed mortality of 61%. Median TTP was 20.2 h with quartiles cutoff Q1 = 15.3, Q2 = 20.2, Q3 = 28, and range 8–104 h. Only APACHE-2 scores predict LOSICU. TTP is not a significant predictor for mortality or LOSICU. Discussion: Data on TTP of blood cultures have a complex interaction with clinical outcomes. Conclusion: TTP of blood cultures does not predict mortality or length of stay in ICU.

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1341. Blood Volume Collected for Blood Cultures in Infants with Suspected Neonatal Sepsis in the NICU

Open Forum Infectious Diseases ◽

10.1093/ofid/ofaa439.1523 ◽

2020 ◽

Vol 7 (Supplement_1) ◽

pp. S682-S682

Author(s):

Maria S Rueda Altez ◽

Lamia Soghier ◽

Joseph M Campos ◽

James Bost ◽

Jiaxiang Gai ◽

...

Keyword(s):

Bloodstream Infection ◽

Blood Volume ◽

Bloodstream Infections ◽

Blood Cultures ◽

Categorical Variables ◽

Continuous Variables ◽

Volume Calculation ◽

Culture Negative ◽

Time Of Collection ◽

Rule Out

Abstract Background Blood cultures have high sensitivity to detect bacteremia in septic neonates when >=1 ml of blood is collected. Neonatologists often cite low confidence in microbiologic sampling as rationale for continuing antibiotics without a focus of infection despite negative blood cultures, resulting in prolonged antimicrobial therapy. We aim to describe the blood culture sample volumes in NICU patients, to identify factors associated with sample volumes < 1ml, and to compare the sample volumes of patients treated for culture-negative sepsis with those with bloodstream infections and those treated for a ≤72-hour sepsis rule-out Methods Data from this observational cohort study were collected retrospectively and prospectively from NICU patients with blood cultures obtained from September 2018 to February 2019. Clinical data were collected through chart review. All inoculated culture bottles were weighed for volume calculation. We determined the association of age, weight, sample source, and time of collection with volume < 1mL. Continuous variables were analyzed using Wilcoxon-Mann-Whitney, and categorical variables using chi-squared test. For aim 3, the volumes of the groups were compared using analysis of variance. Results A total of 310 blood cultures were identified, corresponding to 159 patients. Of these, 49 (16%) were positive. Among the negative blood cultures, 86% were collected in patients who subsequently received antibiotics (Figure 1). Median inoculated volume was 0.6 ml (IQR: 0.1-2.4). Weight and age at time of culture collection, source of sample, and time of collection were not significantly associated with the inoculation of < 1ml of blood. Median volume of blood was 0.6ml (0.3-0.6) for sepsis rule-out, 0.6ml (0.2-0.6) for bloodstream infection, and 0.6ml (0.6-1.4) for culture-negative sepsis. No difference was found among the three groups (p=0.54) Figure 1. Classification of blood cultures identified during study period Conclusion The blood volume collected for cultures in the NICU is lower than recommended. Clinical and environmental characteristics are not significantly associated with the inoculated volume. The volume of blood sampled does not differ in patients with culture-negative sepsis, bloodstream infection and sepsis rule-out, and should not be a justification for longer duration of antibiotic therapy Disclosures All Authors: No reported disclosures

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Scanning Electron Microscope: A New Potential Tool to Replace Gram Staining for Microbe Identification in Blood Cultures

Microorganisms ◽

10.3390/microorganisms9061170 ◽

2021 ◽

Vol 9 (6) ◽

pp. 1170

Author(s):

Gabriel Haddad ◽

Sara Bellali ◽

Tatsuki Takakura ◽

Anthony Fontanini ◽

Yusuke Ominami ◽

...

Keyword(s):

Electron Microscope ◽

Blood Culture ◽

Scanning Electron Microscope ◽

Sample Preparation ◽

Bloodstream Infections ◽

Blood Cultures ◽

Preliminary Identification ◽

Gram Staining ◽

Micro Organisms ◽

Scanning Electron

Blood culture is currently the most commonly used method for diagnosing sepsis and bloodstream infections. However, the long turn-around-time to achieve microbe identification remains a major concern for clinical microbiology laboratories. Gram staining for preliminary identification remains the gold standard. We developed a new rapid strategy using a tabletop scanning electron microscope (SEM) and compared its performance with Gram staining for the detection of micro-organisms and preliminary identification directly from blood cultures. We first optimised the sample preparation for twelve samples simultaneously, saving time on imaging. In this work, SEM proved its ability to identify bacteria and yeasts in morphotypes up to the genus level in some cases. We blindly tested 1075 blood cultures and compared our results to the Gram staining preliminary identification, with MALDI-TOF/MS as a reference. This method presents major advantages such as a fast microbe identification, within an hour of the blood culture being detected positive, low preparation costs, and data traceability. This SEM identification strategy can be developed into an automated assay from the sample preparation, micrograph acquisition, and identification process. This strategy could revolutionise urgent microbiological diagnosis of infectious diseases.

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Bacteremia With Otitis Media

PEDIATRICS ◽

10.1542/peds.87.1.48 ◽

1991 ◽

Vol 87 (1) ◽

pp. 48-53 ◽

Cited By ~ 1

Author(s):

Sara A. Schutzman ◽

Stephen Petrycki ◽

Gary R. Fleisher

Keyword(s):

Staphylococcus Aureus ◽

Streptococcus Pneumoniae ◽

Blood Culture ◽

Haemophilus Influenzae ◽

Otitis Media ◽

Potential Benefit ◽

Blood Cultures ◽

Children At Risk ◽

Focus Of Infection ◽

Persistent Bacteremia

To investigate the occurrence and outcome of bacteremia associated with otitis media, charts were reviewed from patients who were 3 to 36 months of age, had temperatures ≥39°C, and were diagnosed with isolated clinical otitis media. A total of 2982 patients were identified. Blood cultures were obtained from 1666 (56%). Of the 1666 patients, who had blood drawn for cultures, 50 (3.0%) had bacteremia. These included 39 with Streptococcus pneumoniae, 4 with Haemophilus influenzae, 2 with Neisseria meningitidis, 3 with Salmonella species, and 2 with Staphylococcus aureus. The incidence of bacteremia increased at higher temperatures, being 1.9% at temperatures ≤40°C and 5.0% at temperatures >40°C. Younger children were more likely to have bacteremia; 3.7% ≤12 months of age, 2.4% 13 to 24 months of age, and 1.9% 25 to 36 months of age had blood culture results that were positive (not significant). Reevaluation of the 50 bacteremic patients showed that 9 patients had continued fever, 3 patients had persistent bacteremia, pneumonia developed in 1 patient, and meningitis developed in 1 patient. It was concluded that (1) 3% of young febrile children with otitis media have bacteremia at the time of evaluation, a rate comparable to that previously reported in children with no focus of infection; (2) the incidence of bacteremia increases at higher temperatures; and (3) most febrile children with otitis media do well. The clinician must therefore weigh the potential benefit of drawing a blood culture to identify children at risk for complications against the inherent cost, inconvenience, and discomfort.

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Molecular epidemiology of catheter-related bloodstream infections caused by coagulase-negative staphylococci in haematological patients with neutropenia

Epidemiology and Infection ◽

10.1017/s0950268804002584 ◽

2004 ◽

Vol 132 (5) ◽

pp. 921-925 ◽

Cited By ~ 9

Author(s):

M. MÜLLER-PREMRU ◽

P. ČERNELČ

Keyword(s):

Blood Culture ◽

Staphylococcus Epidermidis ◽

Clinical Signs ◽

Bloodstream Infections ◽

Venous Catheter ◽

Blood Cultures ◽

Peripheral Vein ◽

Central Venous ◽

Coagulase Negative Staphylococci ◽

Haematological Patients

Catheter-related bloodstream infection (CRBSI) caused by coagulase-negative staphylococci (CNS) is common in haematological patients with febrile neutropenia. As the clinical signs of CRBSI are usually scarce and it is difficult to differentiate from blood culture contamination, we tried to confirm CRBSI by molecular typing of CNS isolated from paired blood cultures (one from a peripheral vein and another from the central venous catheter hub). Blood cultures were positive in 59 (36%) out of 163 patients. CNS were isolated in 24 (40%) patients; in 14 from paired blood cultures (28 isolates) and in 10 from a single blood culture. CNS from paired blood cultures were identified as Staphylococcus epidermidis. Antimicrobial susceptibility was determined and bacteria were typed by pulsed-field gel electrophoresis (PFGE) of bacterial genomic DNA. In 13 patients, the antibiotic susceptibility of isolates was identical. The PFGE patterns from paired blood cultures were identical or closely related in 10 patients, thus confirming the presence of CRBSI. In the remaining four patients they were unrelated, and suggested a mixed infection or contamination. Since CNS isolates from three patients had identical PFGE patterns, they were probably nosocomially spread amongst them.

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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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Rapid Detection of Methicillin-Resistant Staphylococcus aureus Directly from Blood for the Diagnosis of Bloodstream Infections: A Mini-Review

Diagnostics ◽

10.3390/diagnostics10100830 ◽

2020 ◽

Vol 10 (10) ◽

pp. 830

Author(s):

Anna Rita Buonomini ◽

Elisabetta Riva ◽

Giovanni Di Bonaventura ◽

Giovanni Gherardi

Keyword(s):

Staphylococcus Aureus ◽

Gold Standard ◽

Methicillin Resistant Staphylococcus Aureus ◽

Bloodstream Infections ◽

Rapid Diagnostic Tests ◽

Blood Cultures ◽

High Morbidity ◽

Human Pathogen ◽

Gold Standard Method ◽

Methicillin Resistant

Staphylococcus aureus represents a major human pathogen able to cause a number of infections, especially bloodstream infections (BSI). Clinical use of methicillin has led to the emergence of methicillin-resistant S. aureus (MRSA) and MRSA-BSI have been reported to be associated with high morbidity and mortality. Clinical diagnosis of BSI is based on the results from blood culture that, although considered the gold standard method, is time-consuming. For this reason, rapid diagnostic tests to identify the presence of methicillin-susceptible S. aureus (MSSA) and MRSA isolates directly in blood cultures are being used with increasing frequency to rapidly commence targeted antimicrobial therapy, also in the light of antimicrobial stewardship efforts. Here, we review and report the most common rapid non-molecular and molecular methods currently available to detect the presence of MRSA directly from blood.

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The Addition of Anaerobic Blood Cultures for Pediatric Patients with Concerns for Bloodstream Infections: Prevalence and Time to Positive Cultures

Journal of Clinical Microbiology ◽

10.1128/jcm.01844-19 ◽

2020 ◽

Vol 58 (9) ◽

Author(s):

Jennifer Dien Bard ◽

Todd P. Chang ◽

Rebecca Yee ◽

Keya Manshadi ◽

Nhan Lichtenfeld ◽

...

Keyword(s):

Blood Culture ◽

Pediatric Patients ◽

Bloodstream Infections ◽

Pediatric Emergency ◽

Blood Cultures ◽

Secondary Outcome ◽

Culture Positivity ◽

Blood Culture Positivity ◽

Anaerobic Bottle ◽

Clinically Significant

ABSTRACT Anaerobes are an important but uncommon cause of bloodstream infections (BSIs). For pediatric patients, routine inclusion of an anaerobic blood culture alongside the aerobic remains controversial. We implemented automatic anaerobic blood culture alongside aerobic blood cultures in a pediatric emergency department (ED) and sought to determine changes in recovery of obligate and facultative anaerobes. This was a cohort study in a pediatric ED (August 2015 to July 2018) that began in February 2017. Blood culture positivity results for true pathogens and contaminants were assessed, along with a secondary outcome of time to positivity (TTP) of blood culture. A total of 14,180 blood cultures (5,202 preimplementation and 8,978 postimplementation) were collected, with 8.8% (456) and 7.1% (635) positive cultures in the pre- and postimplementation phases, respectively. Of 635 positive cultures in the postimplementation phase, aerobic blood cultures recovered 7.6% (349/4,615), whereas anaerobic blood cultures recovered 6.6% (286/4,363). In 211/421 (50.0%) paired blood cultures, an organism was recovered in both cultures. The number of cases where organisms were only recovered from an aerobic or an anaerobic bottle in the paired cultures were 126 (30.0%) and 84 (20.0%), respectively. The TTP was comparable regardless of bottle type. Recovery of true pathogens from blood cultures was approximately 7 h faster than recovery of contaminants. Although inclusion of anaerobic blood cultures only recovered 2 (0.69%) obligate anaerobes, it did allow for recovery of clinically significant pathogens that were negative in aerobic blood cultures and supports the routine collection of both bottles in pediatric patients with a concern of bloodstream infections.

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High prevalence of clindamycin resistance in Staphylococcus aureus blood culture isolates in São Paulo, Brazil

Journal of Laboratory Physicians ◽

10.4103/jlp.jlp_161_16 ◽

2017 ◽

Vol 9 (04) ◽

pp. 314-316 ◽

Cited By ~ 1

Author(s):

Felipe S. Lupinacci ◽

Daniel Bussius ◽

Felipe Acquesta ◽

Gustavo Fam ◽

Raphael Rossi ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Blood Culture ◽

Susceptibility Testing ◽

Sao Paulo ◽

Resistance Rate ◽

Blood Cultures ◽

São Paulo ◽

Inducible Clindamycin Resistance ◽

Total Prevalence ◽

High Prevalence

Abstract BACKGROUND: Clindamycin has become an important antimicrobial option for the treatment of Staphylococcus aureus. However, little is known about the current patterns of clindamycin-susceptibility in S. aureus invasive isolates, both in our country and in other developing countries in the world. AIMS: The aim of this study was to determine the prevalence of constitutive and inducible clindamycin resistance in methicillin-susceptible S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) blood culture isolates in São Paulo, Brazil. MATERIALS AND METHODS: From July 2011 to June 2012, all S. aureus isolates from blood cultures collected at our hospital were included in the study. Antimicrobial susceptibility testing was performed according to recommendations of the Clinical and Laboratory Standards Institute. RESULTS: Total prevalence of clindamycin resistance was 68%, including 7.2% with inducible resistance. In MRSA resistance rate was 90.8% whereas in MSSA the rate was 32.7%. CONCLUSIONS: Our high prevalence of clindamycin resistance highlights the importance of performing D-test in a routine base, as well of maintaining continued surveillance for the prevalence of clindamycin resistance.

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Increased Antimicrobial Resistance of Pathogenic Coagulase-Negative Staphylococci From Blood Cultures (1961–1981)

Infection Control ◽

10.1017/s019594170006001x ◽

1984 ◽

Vol 5 (3) ◽

pp. 142-143 ◽

Cited By ~ 1

Author(s):

D.J. Flournoy

Keyword(s):

Staphylococcus Aureus ◽

Blood Culture ◽

Prosthetic Heart Valve ◽

Bacterial Endocarditis ◽

Blood Cultures ◽

Coagulase Negative Staphylococci ◽

Difficult Decision ◽

Antimicrobial Susceptibilities ◽

Cons Isolate ◽

Intravenous Catheters

Coagulase-negative staphylococci (CONS) have only recently gained notoriety as pathogens. Several reports have established their pathogenicity in bacterial endocarditis, prosthetic heart valve endocarditis, intraventricular shunts for treatment of hydrocephalus and intravenous catheters. One difficult decision for physicians is determining whether a particular CONS isolate is pathogenic or contaminant. The differentiation of pathogenic and contaminant CONS has recently been noted, but further studies are needed to aid in this differentiation. Data on antimicrobial susceptibilities of positive blood culture isolates were recently compiled at this institution. This report compares antimicrobial susceptibilities of pathogenic and contaminant CONS and Staphylococcus aureus blood culture isolates from 1961-1981 at this institution.

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