Routine Blood Cultures Research Articles

Different characteristics of bloodstream infection during venoarterial and venovenous extracorporeal membrane oxygenation in adult patients

Currently, there is scarcity of data on whether differences exist in clinical characteristics and outcomes of bloodstream infection (BSI) between venoarterial (VA) and venovenous (VV) extracorporeal membrane oxygenation (ECMO) and whether they differ between Candida BSI and bacteremia in adult ECMO patients. We retrospectively reviewed data of patients who required ECMO for > 48 h and had BSIs while receiving ECMO between January 2015 and June 2020. Cases with a positive blood culture result within 24 h of ECMO implantation were excluded. We identified 94 (from 64 of 194 patients) and 38 (from 17 of 56 patients) BSI episodes under VA and VV ECMO, respectively. Fifty nine BSIs of VA ECMO (59/94, 62.8%) occurred in the first 2 weeks after ECMO implantation, whereas 24 BSIs of VV ECMO (24/38, 63.2%) occurred after 3 weeks of ECMO implantation. Gram-negative bacteremia (39/59, 66.1%) and gram-positive bacteremia (10/24, 41.7%) were the most commonly identified BSI types in the first 2 weeks after VA ECMO implantation and after 3 weeks of VV implantation, respectively. Timing of Candida BSI was early (6/11, 54.5% during the first 2 weeks) in VA ECMO and late (6/9, 66.7% after 3 weeks of initiation) in VV ECMO. Compared with bacteremia, Candida BSI showed no differences in clinical characteristics and outcomes during VA and VV ECMO, except the significant association with prior exposure to carbapenem in VA ECMO (vs. gram-negative bacteremia [P = 0.006], vs. gram-positive bacteremia [P = 0.03]). Our results suggest that ECMO modes may affect BSI clinical features and timing. In particular, Candida BSI occurrence during the early course of VA ECMO is not uncommon, especially in patients with prior carbapenem exposure; however, it usually occurs during the prolonged course of VV ECMO. Consequently, routine blood culture surveillance and empiric antifungal therapy might be warranted in targeted populations of adult ECMO patients, regardless of levels of inflammatory markers and severity scores.

Detection of Pathogenic Bacteria From Septic Patients Using 16S Ribosomal RNA Gene-Targeted Metagenomic Sequencing.

Conventional blood cultures were compared to plasma cell-free DNA-based 16S ribosomal RNA (rRNA) gene polymerase chain reaction (PCR)/next-generation sequencing (NGS) for detection and identification of potential pathogens in patients with sepsis. Plasma was prospectively collected from 60 adult patients with sepsis presenting to the Mayo Clinic (Minnesota) Emergency Department from March through August 2019. Results of routine clinical blood cultures were compared to those of 16S rRNA gene NGS. Nineteen (32%) subjects had positive blood cultures, of which 13 yielded gram-negative bacilli, 5 gram-positive cocci, and 1 both gram-negative bacilli and gram-positive cocci. 16S rRNA gene NGS findings were concordant in 11. For the remaining 8, 16S rRNA gene NGS results yielded discordant detections (n = 5) or were negative (n = 3). Interestingly, Clostridium species were additionally detected by 16S rRNA gene NGS in 3 of the 6 subjects with gastrointestinal sources of gram-negative bacteremia and none of the 3 subjects with urinary sources of gram-negative bacteremia. In the 41 remaining subjects, 16S rRNA gene NGS detected at least 1 potentially pathogenic organism in 17. In 15, the detected microorganism clinically correlated with the patient's syndrome. In 17 subjects with a clinically defined infectious syndrome, neither test was positive; in the remaining 7 subjects, a noninfectious cause of clinical presentation was identified. 16S rRNA gene NGS may be useful for detecting bacteria in plasma of septic patients. In some cases of gram-negative sepsis, it may be possible to pinpoint a gastrointestinal or urinary source of sepsis based on the profile of bacteria detected in plasma.

A preliminary study on percutaneous transhepatic drainage combined with sequential percutaneous nephroscopy in treatment of refractory liver abscess

Objective To investigate the clinical effect of percutaneous transhepatic drainage combined with sequential percutaneous nephroscopy for necrosectomy and drainage in the treatment of refractory liver abscess after transcatheter arterial embolization (TACE). Methods A retrospective analysis was performed for three patients with refractory liver abscess after TACE in The Affiliated 3201 Hospital of Xi'an Jiaotong University School of Medicine from January 2018 to December 2020, and among the three patients, one had the formation of liver abscess after TACE for hepatic metastases after pancreaticoduodenectomy, one had liver abscess after repeated TACE for massive hepatocellular carcinoma, and one had secondary liver abscess after TACE for traumatic hepatic rupture. All three patients received percutaneous transhepatic drainage and sequential percutaneous nephroscopy for the treatment of refractory liver abscess, and their specific treatment process was summarized. Results All three patients were diagnosed with refractory liver abscess based on CT, routine blood test, procalcitonin, blood culture, and clinical manifestation. Percutaneous transhepatic catheterization under the guidance of conventional ultrasonography or CT and effective antibiotics had an unsatisfactory therapeutic effect, and after sequential percutaneous nephroscopy was performed for necrosectomy and drainage, liver abscess was cured and the patients had good prognosis. Conclusion For refractory liver abscess after TACE, when routine puncture treatment has an unsatisfactory therapeutic effect or a patient cannot tolerate surgical operation, percutaneous transhepatic drainage combined with sequential percutaneous nephroscopy is safe and effective in the treatment of refractory liver abscess.

Clinico-bacteriological Profile of Pneumonia, Meningitis and Sepsis in under Five Children from a Tertiary Care Hospital in Central India

Introduction: Invasive Bacterial Diseases (IBD) are the major causes of morbidity and mortality in under five children in India. There is difference in the pattern and aetiology of IBD according to the geographical variation and the antimicrobial susceptibility of causative organisms are also variable. There is lack of data on patterns of IBD from central India. Aim: To generate the data on the burden of pneumonia, meningitis and sepsis among under five children in central India and the microorganisms associated with them. Materials and Methods: This prospective observational study was conducted from August 2019 to July 2020 at the Department of Paediatrics at Mahatma Gandhi Memorial Medical College and MY Hospital, indore, India on children of 1-59 months of age admitted with pneumonia, meningitis and sepsis. A detailed history was recorded for all the participants and thorough physical examination was done along with chest X-ray , routine laboratory examination and blood cultures were performed. Latex Agglutination Test (LAT) and Antibiotic Susceptibility Testing (AST) were performed on Cerebrospinal Fluid (CSF) samples. All the data collected were recorded in Microsoft (MS) excel sheet and frequency (n), percentages (%) and chi-square test for significance level, were calculated to analyse the collected data. Results: Of the total 450 cases enrolled, 283 (62.8%) had confirmed IBD. Out of the confirmed cases, 183 (64.6%) had pneumonia, 52 (18.3%) had meningitis and 48 (16.9%) had sepsis. Highest case fatality rate was seen with sepsis followed by meningitis and pneumonia. The most common organism isolated was Staphylococcus aureus. Overall, gram negative bacilli were found to be more resistant to the conventional antibiotics than gram positive organisms. An 40 (83%) of Staphylococcus aureus were susceptible to methicillin whereas only 12 (45%) of Klebsiella pneumoniae were susceptible to amikacin. Conclusion: The present study highlights the predominance of staphylococcus aureus and adverse outcomes of IBD in children with Severe Acute Malnutrition (SAM) and incomplete immunisation. Emergence of resistant bacterial strains to conventional antibiotics warrants the need to consider the locally prevailing antimicrobial susceptibility patterns for the effective management of these diseases.

The Diagnostic Yield of Routine Admission Blood Cultures in Critically Ill Patients.

Although the Surviving Sepsis Campaign bundle recommends obtaining blood cultures within 1 hour of sepsis recognition, adherence is suboptimal in many settings. We, therefore, implemented routine blood culture collection for all nonelective ICU admissions (regardless of infection suspicion) and evaluated its diagnostic yield. A before-after analysis. A mixed-ICU of a tertiary care hospital in the Netherlands. Patients acutely admitted to the ICU between January 2015 and December 2018. Automatic orders for collecting a single set of blood cultures immediately upon ICU admission were implemented on January 1, 2017. Blood culture results and the impact of contaminated blood cultures were compared for 2015-2016 (before period) and 2017-2018 (after period). Positive blood cultures were categorized as bloodstream infection or contamination. Blood cultures were obtained in 573 of 1,775 patients (32.3%) and in 1,582 of 1,871 patients (84.5%) in the before and after periods, respectively (p < 0.0001), and bloodstream infection was diagnosed in 95 patients (5.4%) and 154 patients (8.2%) in both study periods (relative risk 1.5; 95% CI 1.2-2.0; p = 0.0006). The estimated number needed to culture for one additional patient with bloodstream infection was 17. Blood culture contamination occurred in 40 patients (2.3%) and 180 patients (9.6%) in the before period and after period, respectively (relative risk 4.3; 95% CI 3.0-6.0; p < 0.0001). Rate of vancomycin use or presumed episodes of catheter-related bloodstream infections treated with antibiotics did not differ between both study periods. Implementation of routine blood cultures was associated with a 1.5-fold increase of detected bloodstream infection. The 4.3-fold increase in contaminated blood cultures was not associated with an increase in vancomycin use in the ICU.

The Changing Landscape of Uncomplicated Gram-Negative Bacteremia: A Narrative Review to Guide Inpatient Management.

Gram-negative bacteremia secondary to focal infection such as skin and soft-tissue infection, pneumonia, pyelonephritis, or urinary tract infection is commonly encountered in hospital care. Current practice guidelines lack sufficient detail to inform evidence-based practices. Specifically, antimicrobial duration, criteria to transition from intravenous to oral step-down therapy, choice of oral antimicrobials, and reassessment of follow-up blood cultures are not addressed. The presence of bacteremia is often used as a justification for a prolonged course of antimicrobial therapy regardless of infection source or clinical response. Antimicrobials are lifesaving but not benign. Prolonged antimicrobial exposure is associated with adverse effects, increased rates of Clostridioides difficile infection, antimicrobial resistance, and longer hospital length of stay. Emerging evidence supports shorter overall duration of antimicrobial treatment and earlier transition to oral agents among patients with uncomplicated Enterobacteriaceae bacteremia who have achieved adequate source control and demonstrated clinical stability and improvement. After appropriate initial treatment with an intravenous antimicrobial, transition to highly bioavailable oral agents should be considered for total treatment duration of 7 days. Routine follow-up blood cultures are not cost-effective and may result in unnecessary healthcare resource utilization and inappropriate use of antimicrobials. Clinicians should incorporate these principles into the management of gram-negative bacteremia in the hospital.

ASSOCIATION BETWEEN SEPSIS RISK CALCULATOR AND INFECTION PARAMETERS FOR NEONATES WITH RISK OF EARLY ONSET SEPSIS

C-reactive protein (CRP) is an acute-phase reactant protein that is primarily induced by the IL-6 action during the acute phase of an inflammatory or infectious process. Bacterial infection is a potent stimulus, leading to a rapid elevation of CRP levels within hours while the CBC and symptom are often misleading and/or absent. American Academy of paediatrics (AAP) is recommended routine blood examination test Complete Blood Count (CBC), C-reactive protein (CRP), and blood culture along with empirical antibiotic in neonates with early onset sepsis risk (EOS) risk even asymptomatic. Previous study is showed there were no correlation of CRP and EOS risk. The aim of this study is to evaluate the CRP and CBC profile in neonate with risk of EOS. Methods of this study is using the sepsis risk calculator (SRC) to calculate the probability of neonatal early onset sepsis (EOS) based on maternal risk and infant’s clinical presentation. Neonates with ≥34 weeks of gestation who were started on antibiotic treatment after laboratory examination and blo odculture were taken. EOS risk estimation were compared including CRP, leukocyte, and thrombocyte count. ANOVA applied to distinguished laboratory examination between stratified risk groups. The result is showed using 82 subjects who met the inclusion and exclusion criterias, EOS risk level was stratified into green, yellow, and red group. The p value of CRP level, platelets, white blood cell were 0.35,0.54 and 0.48 where p value was considered as significant if &lt; 0.5. The conclusion of this study is there were no correlation of CRP level and EOS riskASSOCIATION BETWEEN SEPSIS RISK CALCULATOR AND INFECTION PARAMETERS FOR NEONATES WITH RISK OF EARLY ONSET SEPSIS

Laparoscopic pyelolithotomy: its current place in the management of renal pelvis stones

Background: Laparoscopic pyelolithotomy is assumed to preserve functional renal parenchyma, and there is a limited risk for immediate or late renal hemorrhage. Therefore, it might be an alternative for the patients in whom maximal preservation of renal parenchyma is necessary. In the present study, we aimed to compare the success rate and perioperative complications of laparoscopic pyelolithotomy. In the present study, we aimed to document and compare the success rate and perioperative complications of laparoscopic pyelolithotomy with published literature about percutaneous nephrolithotomy (PCNL).Methods: We retrospectively reviewed the clinical charts of all patients subjected to laparoscopic pyelolithotomy (18 cases) in the Department of General Surgery at SMIMER Hospital (tertiary care centre), Surat between the period of January 2014 to December 2018. Record of all patients were assessed for demographic profile, co morbidities, routine blood investigations, including RFT, urine cytology and culture sensitivity, specialized investigation as X-ray KUB, USG KUB, IVP/CT-Urography, DTPA scan, all patients were called for follow up evaluation with radiological, clinical and RFT studies at regular intervals upto 3 months.Results: LP is considered a successful alternative therapy for PCNL in selected cases with large renal stones like those in the extra renal pelvis in patients without a history of previous surgery. In addition, laparoscopic pyelolithotomy (LP) can be considered as a reasonable therapeutic option for large staghorn calculus which cannot be removed with a reasonable number of access and sessions of PCNL.Conclusions: Our results show that laparoscopic pyelolithotomy is equally good or better as compared to PCNL in selected cases.

Value of Blood Cultures in the Management of Children Hospitalized with Community-Acquired Pneumonia.

Background and objectivesCurrent guidelines for the management of community-acquired pneumonia (CAP) in children recommend obtaining a blood culture for children with moderate to severe pneumonia; yet, there is no guidance to assess the severity of the disease. Thus, a blood culture is obtained for the majority of children admitted with CAP, regardless of the severity of their symptoms. The study was designed to investigate and identify the prevalence of bacteremia in pediatric patients hospitalized with CAP and to evaluate the clinical and laboratory variables associated with bacteremia.MethodsWe conducted a medical record review of children aged from two months to 18 years diagnosed with CAP between January 1, 2013, and December 31, 2017, at our two urban tertiary centers. We used binary logistic regression analysis and chi-square tests to look at factors associated with blood culture positivity.ResultsA total of 464 patients were admitted with CAP. Blood cultures were obtained in 357 (76.9%) patients; 23 patients had repeated cultures. Fifteen patients had positive cultures: 5/380 (1.3%) were considered true positive results and 10/380 (2.6%) were considered contaminants. Intensive care unit (ICU) admission (OR 5.6 with 95% CI (1- 31), p<0.03), toxic appearance (OR 12.8 with 95% CI (1.3-125), p<0.01), and significantly elevated C-reactive protein (CRP) (>300 mg/L (p<0.01) were associated with bacteremia.ConclusionThe prevalence of bacteremia among children admitted for CAP is low. The use of routine blood cultures should be reserved for children with moderate to severe pneumonia. Further studies are required to better risk-stratify children with CAP.

Mycobacterium tuberculosis bloodstream infection prevalence, diagnosis, and mortality risk in seriously ill adults with HIV: a systematic review and meta-analysis of individual patient data

SummaryBackgroundThe clinical and epidemiological significance of HIV-associated Mycobacterium tuberculosis bloodstream infection (BSI) is incompletely understood. We hypothesised that M tuberculosis BSI prevalence has been underestimated, that it independently predicts death, and that sputum Xpert MTB/RIF has suboptimal diagnostic yield for M tuberculosis BSI.MethodsWe did a systematic review and individual patient data (IPD) meta-analysis of studies performing routine mycobacterial blood culture in a prospectively defined patient population of people with HIV aged 13 years or older. Studies were identified through searching PubMed and Scopus up to Nov 10, 2018, without language or date restrictions and through manual review of reference lists. Risk of bias in the included studies was assessed with an adapted QUADAS-2 framework. IPD were requested for all identified studies and subject to harmonised inclusion criteria: age 13 years or older, HIV positivity, available CD4 cell count, a valid mycobacterial blood culture result (excluding patients with missing data from lost or contaminated blood cultures), and meeting WHO definitions for suspected tuberculosis (presence of screening symptom). Predicted probabilities of M tuberculosis BSI from mixed-effects modelling were used to estimate prevalence. Estimates of diagnostic yield of sputum testing with Xpert (or culture if Xpert was unavailable) and of urine lipoarabinomannan (LAM) testing for M tuberculosis BSI were obtained by two-level random-effect meta-analysis. Estimates of mortality associated with M tuberculosis BSI were obtained by mixed-effect Cox proportional-hazard modelling and of effect of treatment delay on mortality by propensity-score analysis. This study is registered with PROSPERO, number 42016050022.FindingsWe identified 23 datasets for inclusion (20 published and three unpublished at time of search) and obtained IPD from 20, representing 96·2% of eligible IPD. Risk of bias for the included studies was assessed to be generally low except for on the patient selection domain, which was moderate in most studies. 5751 patients met harmonised IPD-level inclusion criteria. Technical factors such as number of blood cultures done, timing of blood cultures relative to blood sampling, and patient factors such as inpatient setting and CD4 cell count, explained significant heterogeneity between primary studies. The predicted probability of M tuberculosis BSI in hospital inpatients with HIV-associated tuberculosis, WHO danger signs, and a CD4 count of 76 cells per μL (the median for the cohort) was 45% (95% CI 38–52). The diagnostic yield of sputum in patients with M tuberculosis BSI was 77% (95% CI 63–87), increasing to 89% (80–94) when combined with urine LAM testing. Presence of M tuberculosis BSI compared with its absence in patients with HIV-associated tuberculosis increased risk of death before 30 days (adjusted hazard ratio 2·48, 95% CI 2·05–3·08) but not after 30 days (1·25, 0·84–2·49). In a propensity-score matched cohort of participants with HIV-associated tuberculosis (n=630), mortality increased in patients with M tuberculosis BSI who had a delay in anti-tuberculosis treatment of longer than 4 days compared with those who had no delay (odds ratio 3·15, 95% CI 1·16–8·84).InterpretationIn critically ill adults with HIV-tuberculosis, M tuberculosis BSI is a frequent manifestation of tuberculosis and predicts mortality within 30 days. Improved diagnostic yield in patients with M tuberculosis BSI could be achieved through combined use of sputum Xpert and urine LAM. Anti-tuberculosis treatment delay might increase the risk of mortality in these patients.FundingThis study was supported by 10.13039/100010269Wellcome fellowships 109105Z/15/A and 105165/Z/14/A.

Assessment of a rapid diagnostic test to exclude bacteraemia and effect on clinical decision-making for antimicrobial therapy

Unnecessary antimicrobial treatment promotes the emergence of resistance. Early confirmation that a blood culture is negative could shorten antibiotic courses. The Cognitor Minus test, performed on blood culture samples after 12 hours incubation has a negative predictive value (NPV) of 99.5%. The aim of this study was to determine if earlier confirmation of negative blood culture result would shorten antibiotic treatment. Paired blood cultures were taken in the Critical Care Unit at a teaching hospital. The Cognitor Minus test was performed on one set >12 hours incubation but results kept blind. Clinicians were asked after 24 and 48 hours whether a result excluding bacteraemia or fungaemia would affect decisions to continue or stop antimicrobial treatment. Over 6 months, 125 patients were enrolled. The median time from start of incubation to Cognitor Minus test was 27.1 hours. When compared to 5 day blood culture results from both the control and test samples, Cognitor Minus gave NPVs of 99% and 100% respectively. Test results would have reduced antibiotic treatment in 14% (17/119) of patients at 24 and 48 hours (24% at either time) compared with routine blood culture. The availability of rapid tests to exclude bacteraemia may be of benefit in antimicrobial stewardship.

Does This Patient Need Blood Cultures? A Scoping Review of Indications for Blood Cultures in Adult Nonneutropenic Inpatients.

Guidance regarding indications for initial or follow-up blood cultures is limited. We conducted a scoping review of articles published between January 2004 and June 2019 that reported the yield of blood cultures and/or their impact in the clinical management of fever and common infectious syndromes in nonneutropenic adult inpatients. A total of 2893 articles were screened; 50 were included. Based on the reported incidence of bacteremia, syndromes were categorized into low, moderate, and high pretest probability of bacteremia. Routine blood cultures are recommended in syndromes with a high likelihood of bacteremia (eg, endovascular infections) and those with moderate likelihood when cultures from the primary source of infection are unavailable or when prompt initiation of antibiotics is needed prior to obtaining primary source cultures. In syndromes where blood cultures are low-yield, blood cultures can be considered for patients at risk of adverse events if a bacteremia is missed (eg, patient with pacemaker and severe purulent cellulitis). If a patient has adequate source control and risk factors or concern for endovascular infection are not present, most streptococci or Enterobacterales bacteremias do not require routine follow-up blood cultures.

Twelve year analysis of aerobic-only blood cultures for routine detection of bacteraemia

Sampling practices determine the accuracy of blood culture in diagnosing bloodstream infection. The main acute hospital in this study introduced aerobic-only routine blood cultures aiming to increase the volume and number of aerobic samples. At the smaller acute site, aerobic-anaerobic pairs were sent routinely. Culture yield and sampling practices were compared at these two sites and it was found that anaerobic cultures increased the yield of pathogens including facultative anaerobes. Volume cultured and number of samples sent fell short of national recommendations. The aerobic-only policy did not result in more blood being cultured. Based on these findings, the main acute hospital is reintroducing aerobic-anaerobic pairs for routine culture.

T2Candida magnetic resonance in patients with invasive candidiasis: Strengths and limitations.

T2Candida enables detection of five Candida species in whole blood within approximately 5 hours. Routinely drawn EDTA blood samples were prospectively stored and tested with T2Candida in patients with invasive candidiasis identified by routine index blood or sterile site cultures. T2Candida was compared to diagnostic blood and sterile site cultures and also performed with samples obtained prior and after collection of index cultures. T2Candida was evaluated with 133 samples of 32 patients with candidemia and 22 patients with deep-seated invasive candidiasis. In the candidemic group 28/32 (87.5%) patients had at least one positive T2Candida result at any time point. A total of 17/25 (68%) candidemic patients had a positive T2Candida sample that was drawn concurrently to the index blood culture. In the per patient analysis 17/18 (94.4%) candidemic patients with matched T2Candida samples and peripheral blood cultures at any timepoint had a positive T2Candida test. T2Candida revealed discordant Candida species identification in two candidemic patients. Six of 22 (27.3%) deep-seated IC patients had a positive T2Candida result. Despite advanced time-to-results the clinical value of T2Candida in diagnosing candidemia seems to be limited by missing blood culture positive cases. Positivity rates of T2Candida increased when serial T2Candida samples were tested. In patients with suspected deep-seated invasive candidiasis T2Candida might act as a blood based adjunct to sterile site cultures.

Things We Do For No Reason™: Routine Blood Culture Acquisition for Children Hospitalized with Community-Acquired Pneumonia.

Inspired by the ABIM Foundation's Choosing Wisely® campaign, the "Things We Do for No Reason™" (TWDFNR) series reviews practices that have become common parts of hospital care but may provide little value to our patients. Practices reviewed in the TWDFNR series do not represent "black and white" conclusions or clinical practice standards but are meant as a starting place for research and active discussions among hospitalists and patients. We invite you to be part of that discussion.

Ascertaining the burden of invasive Salmonella disease in hospitalised febrile children aged under four years in Blantyre, Malawi.

Typhoid fever is endemic across sub-Saharan Africa. However, estimates of the burden of typhoid are undermined by insufficient blood volumes and lack of sensitivity of blood culture. Here, we aimed to address this limitation by exploiting pre-enrichment culture followed by PCR, alongside routine blood culture to improve typhoid case detection. We carried out a prospective diagnostic cohort study and enrolled children (aged 0–4 years) with non-specific febrile disease admitted to a tertiary hospital in Blantyre, Malawi from August 2014 to July 2016. Blood was collected for culture (BC) and real-time PCR after a pre-enrichment culture in tryptone soy broth and ox-bile. DNA was subjected to PCR for invA (Pan-Salmonella), staG (S. Typhi), and fliC (S. Typhimurium) genes. A positive PCR was defined as invA plus either staG or fliC (CT<29). IgM and IgG ELISA against four S. Typhi antigens was also performed. In total, 643 children (median age 1.3 years) with nonspecific febrile disease were enrolled; 31 (4.8%) were BC positive for Salmonella (n = 13 S. Typhi, n = 16 S. Typhimurium, and n = 2 S. Enteritidis). Pre-enrichment culture of blood followed by PCR identified a further 8 S. Typhi and 15 S. Typhimurium positive children. IgM and IgG titres to the S. Typhi antigen STY1498 (haemolysin) were significantly higher in children that were PCR positive but blood culture negative compared to febrile children with all other non-typhoid illnesses. The addition of pre-enrichment culture and PCR increased the case ascertainment of invasive Salmonella disease in children by 62–94%. These data support recent burden estimates that highlight the insensitivity of blood cultures and support the targeting of pre-school children for typhoid vaccine prevention in Africa. Blood culture with real-time PCR following pre-enrichment should be used to further refine estimates of vaccine effectiveness in typhoid vaccine trials.

Utility of Routine Blood Cultures for Inpatient Hematology/Oncology Patients Receiving Antimicrobials

BackgroundBlood cultures are drawn regularly on hematology/oncology patients due to the concern for infectious complications. However, this practice is costly in many ways, and there are limited data to support this practice. We aimed to investigate the frequency with which blood cultures are drawn in these patients, and moreover, how frequently they provide meaningful data. Materials and MethodsWe performed a single-center retrospective review study in hematology/oncology patients admitted to our hospital. We reviewed 1,437 blood cultures from 220 unique patients between July 1, 2013 and June 30, 2014. We reviewed the proportion and characteristics of the positive blood cultures, as well as organisms isolated. ResultsOf all 1,437 blood cultures drawn during the study period, 111 (8%) of the blood cultures grew a clinically meaningful organism. Gram-positive organisms were more likely than gram-negative organisms, with coagulase-negative Staphylococcus and vancomycin-resistant Enterococcus being most common. In patients who were receiving broad-spectrum antimicrobials, only 13 (4%) of 358 blood cultures collected grew a clinically meaningful organism, all of which were performed for clearance. None of these 13 positive blood cultures represented a new infectious organism. No patient receiving broad-spectrum antibiotics with blood cultures drawn in response to a fever had a positive culture. ConclusionsIn hospitalized cancer patients receiving broad-spectrum antimicrobials, the likelihood of growing a new clinically significant organism from a blood culture was extremely low. We speculate that the practice of repeating blood cultures in hospitalized cancer patients on broad-spectrum antimicrobials, particularly in response to fever alone, should be eliminated.

Rapid Diagnostics for Blood Cultures: Supporting Decisions for Antimicrobial Therapy and Value-Based Care.

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.

Pediatric Anaerobic Blood Culture Practices in Industrialized Countries.

Routine anaerobic blood culture collection in febrile children is controversial, as clinicians try to account for the severe but relative infrequency of anaerobic bacteremia. Furthermore, clinical and laboratory practice variation among institutions may lead to potentially inaccurate epidemiological data. Our goal was to assess blood culture practices in pediatric patients throughout an international network of hospitals in industrialized countries. We conducted a survey of current clinical and laboratory practice patterns in a convenience sample of international institutions participating in 6 pediatric emergency research networks in the US, Canada, Europe, Australia, and New Zealand. A lead clinician at each institution queried institutional practices from the emergency department, pediatric intensive care unit, and oncology medical directors. The microbiology director at each institution completed the laboratory survey. Sixty-five of 160 (41%) invited institutions participated in the survey. Routine anaerobic blood cultures are collected in 30% of emergency departments, 30% of intensive care units, and 48% of oncology wards. Reasons for restricting anaerobic culture collection included concerns regarding blood volume (51%), low pretest probability (22%), and cost-effectiveness (16%). The most common reasons institutions allow for selectively obtaining anaerobic cultures are clinical suspicion (64%) and patients who are immunosuppressed (50%). The microbiology survey showed variation in systems, although most use the BACTEC™ culture system and MALDI-TOF for organism identification. There is broad variation in anaerobic blood culture practices among a network of pediatric hospitals in industrialized countries.

2054. Physician Responses to Positive Rapid Diagnostic Tests for Candida Fungemia in the Absence of Concomitant Positive Blood Cultures

Background Candida species are the fourth leading cause of nosocomial bloodstream infections in the United States. Unfortunately, detection, identification and susceptibility testing using standard instrumented blood culture systems and routine microbiological techniques may take 4–10 days. Moreover, sensitivity of routine blood cultures for candidemia is only ~50 to 75%. The T2 Candida Panel (T2CP) is an FDA-approved assay that rapidly detects the presence of five Candida species directly from whole blood in 3–5 hours. We examined mortality and antifungal therapy (AFT) decisions based on positive (pos) results of a T2CP in patients with negative (neg) blood cultures.MethodsWe performed a case series of all patients who had a pos T2CP with concomitant neg blood cultures at our institution from March 1, 2016 to March 1, 2018. If a patient had multiple valid T2CP, only the first pos result was used for analysis. Medical records were reviewed for demographics, comorbidities, risk factors for candida infection, length of stay, use and duration of AFT, and 14-day and in-hospital mortality from the time of the T2CP.ResultsFifteen patients were identified who met inclusion criteria. Eight patients were immunocompromised: four (26.7%) solid cancer malignancy, three (20%) hematologic malignancy, and one kidney transplant recipient. Pos T2CP results by species were as follows: 53.3% C. albicans/C. tropicalis, 40% C. parapsilosis, and 6.7% C. glabrata/C. krusei. Median SOFA, Charlson comorbidity index, and Candida scores were 6, 6, and 9, respectively. Fourteen-day mortality was 40% and in-hospital mortality was 53.3%. Only two patients were on prophylactic AFT due to an underlying hematologic malignancy at the time of T2CP; in both cases, azole AFT was replaced with an echinocandin in response to the pos T2CP. Of the remaining 13 patients who were not on prophylactic AFT, all were started on AFT after pos T2CP result.ConclusionPhysicians escalated or initiated AFT therapy based on pos T2CP in severely ill patients who had negative blood cultures. Unfortunately, the population had high severity index scores and high mortality despite initiation or escalation of AFT. We hypothesize that earlier testing and detection of Candida fungemia may lead to faster initiation of AFT and better outcomes.Disclosures All authors: No reported disclosures.