Clinical Blood Culture Research Articles

Rapid Rule Out of Culture-Negative Bloodstream Infections by Use of a Novel Approach to Universal Detection of Bacteria and Fungi.

Currently it can take up to 5 days to rule out bloodstream infection. With the low yield of blood cultures (approximately 10%), a significant number of patients are potentially exposed to inappropriate therapy that can lead to adverse events. More rapid rule out can accelerate deescalation or cessation of antimicrobial therapy, improving patient outcomes. A method is described, termed enzymatic template generation and amplification (ETGA), that universally and sensitively detects DNA polymerase activity liberated from viable bacteria and fungi isolated from blood culture samples as a measure of bloodstream infection. ETGA was applied in a diagnostic test format to identify negative blood cultures after an overnight incubation. Performance data for a prototype (Cognitor) and automated (Magnitor) version of the test are presented. The Cognitor manual assay displayed analytical reactivity for a panel of the 20 most prevalent causes of bloodstream infection, with a detection range of 28-9050 CFU/mL. Validation with 1457 clinical blood cultures showed a negative predictive value of 99.0% compared to blood culture incubation for 5 days. Magnitor showed an improved detection range of 1-67 CFU/mL, allowing for detection of bacteria-supplemented blood cultures after 2-8 h incubation, and Candida albicans-supplemented blood cultures at 16-22 h, 5-15 h faster than blood culture. Removing an aliquot from a blood culture bottle and replacing the bottle into the incubator was shown not to result in contaminating organisms being introduced. The described method displays excellent breadth and detection for microbial cells and demonstrates the capability of confirming negative blood cultures after an overnight incubation in a blood culture instrument.

2289. Accuracy of a Rapid Multiplex PCR Plus a Chromogenic Phenotypic Test Algorithm for the Detection of ESBL and Carbapenemase-Producing Gram Negatives Directly From Blood Cultures

BackgroundWe studied the multiplex PCR panel (BioFire Blood Culture ID panel, “BCID”) with phenotypic testing using the Rosco Diagnostica Rapid ESBL Screen kit 98022 (RE) and the Neo-Rapid CARB kit 98024 (RC) for extended-spectrum β-lactamase (ESBL)/carbapenemase producing Gram negative bacilli (CPGNB) detection directly from blood culture bottles, in patients with Gram negative bacteremia.MethodsThe RE and RC kits were evaluated in a verification phase with 98 blood cultures, comprising 43 spiked with GNB: 23 Escherichia coli, 9 Klebsiella pneumoniae, 7 Enterobacter cloacae, 2 Serratia marcescens, one Pseudomonas aeruginosa, one Acinetobacter baumanii complex with varying resistance genotypes (11 CTX-M-15, 5 CTX-M9, one SHV-18, one SHV-3, one TEM-10, 3 IMI, 4 IMP, 4 KPC, 2 NDM, one OXA-23+OXA-51-like, 3 OXA-232, one OXA-48, one SME-1, 2 VIM-1, 2 AmpC from reference and clinical isolate banks, and ATCC 25922), and 54 clinical blood cultures with GNB (5 phenotypic ESBL-positive, one KPC, 48 no known β-lactamase). In a prospective phase, a further 123 clinical blood cultures positive for GNB were tested simultaneously with the BCID, RE and RC kits.ResultsIn the verification phase, the RE kit detected 24/25 of ESBL-positive samples (sensitivity 96%, specificity 99%). The RE kit did not detect the 2 AmpC-producers, and was positive for a K. oxytoca isolate, which are known to produce chromosomally encoded β-lactamases. The RC kit detected 11/22 of CPGNB (sensitivity 50%, specificity 100%). It missed IMI, OXA-23+OXA-51-like, OXA-232, OXA-48, SME-1 and VIM CPGNB (weak carbapenemases), but detected NDM, KPC, IMP. In the prospective phase, the RE kit detected 20/20 ESBL-positive blood culture samples (sensitivity 100%). The single OXA-48 positive sample was detected by both the RE and RC kits. The 123 blood cultures had a total of 125 panel-represented targets detectable by BCID. The BCID detected 124 /125 (missed one K. pneumoniae in a polymicrobial bacteremia), and there were 2 Proteus false-positives (sensitivity 99%, specificity 98%). No KPC-positive samples were detected by BCID.ConclusionAn algorithm comprising the BCID and the RE/RC kits applied to positive blood cultures allows both rapid and accurate pathogen identification and detection of ESBLs and some carbapenemases (e.g., KPC, NDM, IMP). This may allow the institution of timelier, directed therapy.Disclosures S. Vasoo, bioMerieux: Grant Investigator, Research support. Rosco Diagnostica: In-kind support, Research support. R. Banerjee, Accelerate Diagnostics, Biomerieux, BioFire: Grant Investigator, Research grant and Research support. R. Patel, CD Diagnostics, BioFire, Curetis, Merck, Hutchison Biofilm Medical Solutions, Accelerate Diagnostics, Allergan, and The Medicines Company: Grant Investigator, Research grant - monies paid to Mayo Clinic. Curetis, Specific Technologies, Selux Dx, GenMark Diagnostics, PathoQuest and Genentech: Consultant and Scientific Advisor, Consulting fee - monies paid to Mayo Clinic. ASM and IDSA: Travel reimbursement and editor’s stipends, Travel reimbursement and editor’s stipends. NBME, Up-to-Date and the Infectious Diseases Board Review Course: Varies, Honoraria. Mayo Clinic: Employee, Salary.

Common Pathogens Associated with Neonatal Sepsis and Their Antibiotic Resistance Pattern in Sohag University Hospital

Introduction: Neonatal sepsis is defined as a clinical syndrome in an infant 28 days of life or younger, manifested by systemic signs of infection and isolation of a bacterial pathogen from the bloodstream[EmanShehab El-Din et al, 2015]. Positive blood culture and sensitivity of the isolate is the best guide to antimicrobial therapy and once started should be modified according to the culture sensitivity reports[Aggarwalet al, 2001]. Aim of the work: To determine clinical and microbiological pattern of neonatal sepsis in Sohag university hospital with special focus on causative pathogens and their response to used antimicrobials. Patient and methods: Our study conducted over a period of 18 months between October 2015 and April 2017 at Sohag university hospital and included 75 neonates with suspected sepsis and positive blood culture using Egyptian neonatal network (EGNN) guidelines, subjected to full clinical examination, septic screen(CBC, ESR and CRP) and blood culture and sensitivity tests. Results: All studied neonates presented with late onset sepsis with higher incidence in infants born via CS especially with low and very low birth weight.The incidence of neonatal sepsis was predominantly due gram negative bacteria mainly Klepseillapneumonae followed by staphylococcus haemolyticusandstaphylococcus epidermidis. Klebseilla isolates showed high sensitivity for aminoglycosides and quinolones antibiotics with resistance to penicillin's group, Staphylococcus isolates showed resistance to penicillin's and aminoglycosides while sensitive to quinolones and nitrofurantions. E.coli and Pseudomonas species showed moderate sensitivity to 3rd generation cephalosporins, aminoglycosides, quinolones and nitrofurantoins with resistance to classic penicillin's. Conclusion: In our study gram negative bacteria mainly Klepseillapneumonae was the most causative agent of neonatal sepsis. Most isolated organisms showed resistance to classic penicillins.Klepseillapneumonaeshowed high sensitivity for aminoglycosides and quinolones, Staphylococcus isolates showed high sensitivity to quinolones and nitrofurantions while E.coli and Pseudomonas species showed moderate sensitivity to 3rd generation cephalosporins, aminoglycosides, quinolones and nitrofurantoins.

Hypermucoviscous Klebsiella pneumoniae infections induce platelet aggregation and apoptosis and inhibit maturation of megakaryocytes

IntroductionDifferent Klebsiella pneumoniae strains carry different virulence factors and antibiotic resistance and may cause thrombocytopenia. This study aimed to investigate the effects of different infections caused by K. pneumoniae on platelets. MethodsTwo hypermucoviscous K. pneumoniae strains and two classic strains were collected from clinical blood culture, and in both groups, there was a carbapenem-resistant strain and a carbapenem-sensitive strain. Mouse infection models were constructed by intraperitoneally injecting different strains, and mice injected with phosphate-buffered saline served as a control. Count, aggregation rate and apoptosis proportion of platelets within 12 h were examined. CD41 expression was measured in bone marrow cells to determine the maturation of megakaryocytes. The concentrations of lipopolysaccharides and related signaling molecules were also measured. ResultsThe platelet aggregation rate was much significantly higher in the two hypermucoviscous groups, while it showed no difference in the classic groups compared to the control group. All infections induced apoptosis of platelets, among which the highest apoptosis proportions were observed in infections caused by the hypermucoviscous carbapenem-sensitive strain. In both hypermucoviscous groups the CD41 mean fluorescence intensity was much lower than that in the control group, indicating that the maturation of megakaryocytes in the hypermucoviscous groups was significantly inhibited. Lipopolysaccharides were significantly higher and TLR4/Myd88 and JNK/MAPK pathways were strongly activated in hypermucoviscous groups. ConclusionsThe results indicate that hypermucoviscous K. pneumoniae can reduce platelet count by several pathways. Although antibiotic resistance is rapidly emerging worldwide, it has little influence on the decrease in platelets.

Does ivacaftor interfere with the antimicrobial activity of commonly used antibiotics against Pseudomonas aeruginosa?-Results of an in vitro study.

Ivacaftor is a novel potentiator of defective cystic fibrosis transmembrane conductance regulator (CFTR) protein, which corrects the gating defect and increases ion-function of activated cell-surface CFTR. Bacteria also regulate their physiology through ion channels. However, little is known about the potential effects of ivacaftor on bacterial ion channels, which, in turn, may have a potential effect on transport across the bacterial cell membrane. Therefore, any change in the ability to transport molecules across cell membranes in bacteria could have an important impact on bacterial transport physiology. One area where this could be particularly important is in the movement of antibiotics, both into and out of the bacterial cell. An in vitro study was therefore performed to examine the influence of ivacaftor at therapeutic concentration on antibiotic susceptibility of 11 commonly used anti-pseudomonal antibiotics against a population of clinical Pseudomonas aeruginosa [PA], from CF and non-CF sources. Pseudomonas aeruginosa (n=80; including 70 ivacaftor-naïve clinical PA from sputa from adult CF patients and 10 control PA from non-CF clinical blood culture sources) were examined. Antibiotic susceptibility was determined by standard disc diffusion assay using CLSI criteria and measuring zone size (mm), against four classes of anti-pseudomonal antibiotics, including beta-lactams (temocillin, ceftazidime, piperacillin/tazobactam, imipenem, meropenem and aztreonam), aminoglycosides (gentamicin, tobramycin, amikacin), fluoroquinolone (ciprofloxacin) and polymyxin (colistin), in the absence and presence of ivacaftor (5μmol/L), as previously determined. In addition, all CF and non-CF PA were examined phenotypically in vitro, as previously described, for changes linked to bacterial virulence, including (i) growth density (ii) pigmentation, (iii) presence of adhesins and (iv) change to mucoidy, in the presence/absence of ivacaftor at therapeutic concentration. Antibiotic susceptibility did not decrease significantly with any of the antibiotics examined with CF PA isolates or with non-CF PA control organisms. There was a statistically significant increase in zone size (CF PA and amikacin, gentamicin, temocillin and ciprofloxacin; Non-CF PA and amikacin, gentamicin and aztreonam). However, at a population level, this did not translate into a shift in CLSI category to a more susceptible phenotype. None of the PA isolates examined were susceptible to ivacaftor alone, and additionally, no changes were noted with the four phenotypic parameters examined in the presence of ivacaftor. This study showed that antibiotic susceptibility of commonly used anti-pseudomonal antibiotics was not negatively affected by ivacaftor, in a population of ivacaftor-naive P.aeruginosa.

Rapid detection of carbapenemase activity of Enterobacteriaceae isolated from positive blood cultures by MALDI-TOF MS

BackgroundMatrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has been proved to be a useful tool for identification of pathogens directly isolated from blood cultures in clinical microbiology laboratories. β-Lactam antibiotics are commonly used for treatment of bloodstream infections caused by Enterobacteriaceae strains, and carbapenem is the superlative class of β-lactam antibiotics. Since the carbapenem resistance rate of Enterobacteriaceae strains raised year by year, efficient detection of carbapenemase activity and timely delivery of carbapenem susceptibility reports of Enterobacteriaceae strains isolated from blood cultures is important for clinicians.MethodsWe used 64 simulated blood cultures to establish the method of MALDI-TOF MS based ertapenem hydrolysis assay. The cutoff value of logRQ calculated from the peaks intensity of ertapenem and its hydrolysate was first set to identify the strains with carbapenemase activity. Then, we detected and calculated the logRQ values of 385 Enterobacteriaceae strains from positive clinical blood cultures to distinguish the carbapenemase producers and noncarbapenemase producers.ResultsThe mean logRQ value of 32 noncarbapenemase producers was − 0.85 ± 0.14 in simulated blood cultures, while the logRQ value of 32 carbapenemase producers was 0.87 ± 0.55. Thus, the cutoff value of logRQ was set at − 0.45 with sensitivity of 100% and specificity of 100%. In 385 clinical positive blood cultures, the logRQ values of all carbapenem-susceptible Enterobacteriaceae strains (81.3%, 313/385) were < − 0.45. Comparing with the detection of carbapenemase genes, carbapenem-resistant Enterobacteriaceae strains (18.7%, 72/385) were well distinguished by MALDI-TOF MS based ertapenem hydrolysis assay with a sensitivity of 92.5% and specificity of 100%.ConclusionsOur data show that MALDI-TOF MS based ertapenem hydrolysis assay is a rapid and accurate method to detect carbapenemase activity of Enterobacteriaceae strains from positive blood cultures, and can be routinely performed in clinical microbiology laboratories.

An Automated Sample Preparation Instrument to Accelerate Positive Blood Cultures Microbial Identification by MALDI-TOF Mass Spectrometry (Vitek®MS).

Sepsis is the leading cause of death among patients in intensive care units (ICUs) requiring an early diagnosis to introduce efficient therapeutic intervention. Rapid identification (ID) of a causative pathogen is key to guide directed antimicrobial selection and was recently shown to reduce hospitalization length in ICUs. Direct processing of positive blood cultures by MALDI-TOF MS technology is one of the several currently available tools used to generate rapid microbial ID. However, all recently published protocols are still manual and time consuming, requiring dedicated technician availability and specific strategies for batch processing. We present here a new prototype instrument for automated preparation of Vitek®MS slides directly from positive blood culture broth based on an “all-in-one” extraction strip. This bench top instrument was evaluated on 111 and 22 organisms processed using artificially inoculated blood culture bottles in the BacT/ALERT® 3D (SA/SN blood culture bottles) or the BacT/ALERT VirtuoTM system (FA/FN Plus bottles), respectively. Overall, this new preparation station provided reliable and accurate Vitek MS species-level identification of 87% (Gram-negative bacteria = 85%, Gram-positive bacteria = 88%, and yeast = 100%) when used with BacT/ALERT® 3D and of 84% (Gram-negative bacteria = 86%, Gram-positive bacteria = 86%, and yeast = 75%) with Virtuo® instruments, respectively. The prototype was then evaluated in a clinical microbiology laboratory on 102 clinical blood culture bottles and compared to routine laboratory ID procedures. Overall, the correlation of ID on monomicrobial bottles was 83% (Gram-negative bacteria = 89%, Gram-positive bacteria = 79%, and yeast = 78%), demonstrating roughly equivalent performance between manual and automatized extraction methods. This prototype instrument exhibited a high level of performance regardless of bottle type or BacT/ALERT system. Furthermore, blood culture workflow could potentially be improved by converting direct ID of positive blood cultures from a batch-based to real-time and “on-demand” process.

Simple Sample Preparation Method for Direct Microbial Identification and Susceptibility Testing From Positive Blood Cultures.

Rapid identification and determination of the antibiotic susceptibility profiles of the infectious agents in patients with bloodstream infections are critical steps in choosing an effective targeted antibiotic for treatment. However, there has been minimal effort focused on developing combined methods for the simultaneous direct identification and antibiotic susceptibility determination of bacteria in positive blood cultures. In this study, we constructed a lysis-centrifugation-wash procedure to prepare a bacterial pellet from positive blood cultures, which can be used directly for identification by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) and antibiotic susceptibility testing by the Vitek 2 system. The method was evaluated using a total of 129 clinical bacteria-positive blood cultures. The whole sample preparation process could be completed in <15 min. The correct rate of direct MALDI-TOF MS identification was 96.49% for gram-negative bacteria and 97.22% for gram-positive bacteria. Vitek 2 antimicrobial susceptibility testing of gram-negative bacteria showed an agreement rate of antimicrobial categories of 96.89% with a minor error, major error, and very major error rate of 2.63, 0.24, and 0.24%, respectively. Category agreement of antimicrobials against gram-positive bacteria was 92.81%, with a minor error, major error, and very major error rate of 4.51, 1.22, and 1.46%, respectively. These results indicated that our direct antibiotic susceptibility analysis method worked well compared to the conventional culture-dependent laboratory method. Overall, this fast, easy, and accurate method can facilitate the direct identification and antibiotic susceptibility testing of bacteria in positive blood cultures.

Outcomes of infective endocarditis in the current era: Early predictors of a poor prognosis

BackgroundThe early identification of patients at risk of complications of infective endocarditis (IE) using parameters obtained as part of routine practice is essential for guiding clinical decision-making. This study aimed to identify a parameter at hospital admission that predicts the outcome, adding value to other well-known factors of a poor prognosis in IE. MethodsTwo hundred and three patients with IE were included in this study. Clinical evaluation, echocardiography, blood cultures, and routine laboratory tests were performed at hospital admission. The endpoint was in-hospital mortality. ResultsThe mean age of the patients was 48.2±16.6 years; 62% were male and 38% had rheumatic heart disease. During treatment, cardiac surgery was performed in 111 patients (55%), and the overall in-hospital mortality rate was 32%. In the multivariable analysis, the independent predictors of death were age (odds ratio (OR) 1.07, 95% confidence interval (CI) 1.02–1.13), C-reactive protein (CRP) at hospital admission (OR 1.12, 95% CI 1.04–1.21), length of the vegetation at diagnosis (OR 1.15, 95% CI 1.03–1.28), development of heart failure (OR 6.43, 95% CI 2.14–19.33), and embolic events during antimicrobial therapy (OR 12.14, 95% CI 2.11–71.89). ConclusionsAn elevated CRP level at hospital admission and vegetation length at diagnosis were strong predictors of in-hospital mortality in IE, independent of other prognostic parameters, specifically taking into account patient characteristics and complications during therapy.

Use of central venous access devices and its complications in neonates

Background: Intravenous therapy is a major component in the health care and appropriate research-based knowledge is essential to ensure positive patient outcomes. Objective: The objective of the study was to study the use of Central Venous Access Devices (CVADs) and their complications in neonates in routine practice. Methods: A prospective observational study was conducted at a tertiary care neonatal intensive care unit (NICU) on 40 newborns. CVADs were inserted in neonates, who had been anticipated to have intravenous access for &gt;7 days. CVADs used in the study included Peripherally Inserted Central Catheters (PICCs) and umbilical venous catheters. CVADs were inserted under strict aseptic precautions as per international guidelines, and maintenance protocols followed. Monitoring for complications was done daily. Central Line Associated Blood Stream Infection (CLABSI) was established by a combination of suggestive clinical signs and blood culture reports as per Centre for Disease Control and prevention definition. Results: Extremely low birth weight neonates contributed 40% of the patients. PICC insertions formed the 85% of the devices used. Basilic vein was the preferred site of the insertion in almost one-half of the patients. 80% of the PICCs in neonates were used to administer total parenteral nutrition. CLABSI was the most common complication occurring at a rate of 7.5/1000 catheter days. Other complications were occlusion, suspected infection, accidental displacement, and thromboembolism. Conclusion: Central venous catheterization is a safe and efficient procedure with minimal complication in neonates. This study emphasizes its use whenever prolonged intravenous access requirement is expected.

Observational Study of Infective Endocarditis at a Community-based Hospital: Dominance of Elderly Patients with Comorbidity.

Objective The purpose of this study was to present the recent clinical profiles and the real-world management of infective endocarditis (IE). Methods All medical records of patients with IE were reviewed retrospectively for their clinical data, including clinical presentation, laboratory results, blood cultures, echocardiographic findings, treatments and complications. Using the clinical data collected, we calculated the EuroSCORE II, the European risk score for adult cardiac surgery, the Charlson Comorbidity Index as a surrogate of comordibity, and the Katz Index as a surrogate of frailty. Results Thirty-eight patients were identified as having IE (24 men, age: 71.8±13.1 years). Congestive heart failure occurred in 16 patients (42%), stroke in 14 (50%), and systemic embolism in 5 (13%). The EuroSCORE II and Charlson Comorbidity Index were high (7.7±5.8% and 5.5±2.8%, respectively). The Katz Index was fair (5.5±1.4) before the onset but deteriorated to 2.8±2.7 at the time of establishing the diagnosis of IE (p<0.001). Early surgery was performed in 22 cases (61%). In-hospital death occurred in 10 cases (26%). A EuroSCORE II ≥9%, Staphylococcus aureus etiology, and a Charlson Comorbidity Index were suggested as determinants of in-hospital death (hazard ratios: 173.60, 9.31, 1.57, respectively). In contrast, early surgery was suggested as a determinant of the survival (hazard ratio: 0.04). The Charlson Comorbidity Index was also suggested as a determinant for selecting conservative management (odds ratio: 1.40). Conclusion Comorbidity may influence the treatment selection and outcome of elderly patients with IE.

Mycobacterium grossiae sp. nov., a rapidly growing, scotochromogenic species isolated from human clinical respiratory and blood culture specimens.

A previously undescribed, rapidly growing, scotochromogenic species of the genus Mycobacterium (represented by strains PB739T and GK) was isolated from two clinical sources - the sputum of a 76-year-old patient with severe chronic obstructive pulmonary disease, history of tuberculosis exposure and Mycobacterium avium complex isolated years prior; and the blood of a 15-year-old male with B-cell acute lymphoblastic leukaemia status post bone marrow transplant. The isolates grew as dark orange colonies at 25-37 °C after 5 days, sharing features in common with other closely related species. Analysis of the complete 16S rRNA gene sequence (1492 bp) of strain PB739T demonstrated that the isolate shared 98.8 % relatedness with Mycobacterium wolinskyi. Partial 429 bp hsp65 and 744 bp rpoB region V sequence analyses revealed that the sequences of the novel isolate shared 94.8 and 92.1 % similarity with those of Mycobacterium neoaurum and Mycobacterium aurum, respectively. Biochemical profiling, antimicrobial susceptibility testing, HPLC/gas-liquid chromatography analyses and multilocus sequence typing support the taxonomic status of these isolates (PB739T and GK) as representatives of a novel species. Both isolates were susceptible to the Clinical and Laboratory Standards Institute recommended antimicrobials for susceptibility testing of rapidly growing mycobacteria including amikacin, ciprofloxacin, moxifloxacin, doxycycline/minocycline, imipenem, linezolid, clarithromycin and trimethropin/sulfamethoxazole. Both isolates PB739T and GK showed intermediate susceptibility to cefoxitin. We propose the name Mycobacterium grossiae sp. nov. for this novel species and have deposited the type strain in the DSMZ and CIP culture collections. The type strain is PB739T (=DSM 104744T=CIP 111318T).

Automated direct screening for resistance of Gram-negative blood cultures using the BD Kiestra WorkCell.

Early detection of resistance in sepsis due to Gram-negative organisms may lead to improved outcomes by reducing the time to effective antibiotic therapy. Traditional methods of resistance detection require incubation times of 18 to 48h to detect resistance. We have utilised automated specimen processing, digital imaging and zone size measurements in conjunction with direct disc susceptibility testing to develop a method for the rapid screening of Gram-negative blood culture isolates for resistance. Positive clinical blood cultures with Gram-negative organisms were prospectively identified and additional resistant mock specimens were prepared. Broth was plated and antibiotic-impregnated discs (ampicillin, ceftriaxone, piperacillin-tazobactam, meropenem, ciprofloxacin, gentamicin) were added. Plates were incubated, digitally imaged and zone sizes were measured using the BD Kiestra WorkCell laboratory automation system. Minimum, clinically useful, incubation times and optimised zone size cut-offs for resistance detection were determined. We included 187 blood cultures in the study. At 5h of incubation, >90% of plates yielded interpretable results. Using optimised zone size cut-offs, the sensitivity for resistance detection ranged from 87 to 100%, while the specificity ranged from 84.7 to 100%. The sensitivity and specificity for piperacillin-tazobactam resistance detection was consistently worse than for the other agents. Automated direct disc susceptibility screening is a rapid and sensitive tool for resistance detection in Gram-negative isolates from blood cultures for most of the agents tested.

Management of Endograft Infection After EVAR and TEVAR - a Case Series and Literature Review

Introduction Endograft infection after EVAR (Endovascular aortic repair) or TEVAR (Thoracic endovascular aortic repair) is a rare but severe complication with high mortality. As the number of patients with endovascular aneurysm repair has increased over the last decade, the number of patients with endograft infection might also have increased. However, no guideline defines the treatment of endograft infection. Diagnosis is difficult and depends on clinical symptoms, radiological imaging and blood cultures. Surgery with graft excision, debridement and revascularisation should be proposed. Several techniques and graft materials are used. Additionally long term antibiotic therapy under close control of inflammation markers is always required. Methods We conducted a retrospective analysis of all patients treated for infected aortic endografts in our hospital between January 2008 and May 2017. Study endpoints were freedom from reinfection, survival and primary patency. An extensive electronic health database search was performed to identify articles reporting endograft infection after EVAR and TEVAR. Results We detected aortic endograft infection in three patients (100% male, median age 77 years). In all cases, infrarenal endovascular aortic aneurysm repair had been performed. The infected stent grafts were removed and anatomical revascularisation performed. One homograft and two xenografts were used as graft material. No patient was treated conservatively. A causative organism was found in 2 of the 3 cases. The patients received antibiotics for 12 weeks. Thirty day mortality was 0%. During follow-up, one patient died from bowel perforation after 2 months and another from lung cancer after 92 months. There were no reinfections. Primary patency of the reconstructions was 100%. Publications report high mortality after conservative therapy of endograft infection. There is evidence for lower mortality in patients who underwent surgery. Conclusions Removal of the infected graft, anatomical revascularisation and antibiotic therapy are important for long term survival after aortic endograft infection. Conservative therapy is only warranted in patients unsuitable for surgical treatment.

Study of Clinical Profile and Antibiotic Response in Typhoid Fever at Faridpur Medical College Hospital

The objectives of this present study is to evaluate the clinical profile and pattern of various drugs used in the treatment of typhoid fever. A retrospective analysis of Paediatric patients suffering from typhoid fever was done at Department of Paediatrics, Faridpur Medical College Hospital, Faridpur during the year 2015-2016. Diagnosis of patients was based on clinical features, Widal test and blood culture. The sensitivity pattern of isolates from blood culture was recorded. The mode of presentation, clinical course, treatment history, laboratory investigations reports, antibiotic administered, response to therapy and the complications were recorded. Total number of 50 cases of typhoid fever were studied. Out of these 23 (46%) were males and 27 (54%) were females. Average age of presentation was 8.2 years. Average duration of hospital stay was 10.8 days. Fever was present in all patients. Resistance of S. typhi to amoxicillin, chloramphenicol, ampicillin and co-trimoxazole were significantly high. Ciprofloxacin also showed resistance in 21.4% of cases. Sensitivity to cephalosporin was 100% in our study. Ciprofloxacin was the most commonly used antibiotic in our study (26 patients). Chloramphenicol alone was used in 2 patients and in 3 patients it was given after 6 days of ciprofloxacin treatment. Third generation cephalosporin (ceftriaxone) alone were used in 10 patients. Indiscriminate use of drugs in typhoid fever should be discouraged. Appropriate antibiotic as indicated by sensitivity tests should be employed to prevent the development of resistant strains of S. typhi.Faridpur Med. Coll. J. Jan 2017;12(1): 2-4

Comparison of ‘time to detection’ values between BacT/ALERT VIRTUO and BacT/ALERT 3D instruments for clinical blood culture samples

ObjectivesThe early detection of bacteraemia and fungemia is of paramount importance to guide antimicrobial therapy in septic patients. In this study the ‘time to detection’ (TTD) value for the new blood culture system BacT/ALERT VIRTUO (VIRTUO) was evaluated in 1462 positive clinical bottles and compared with the TTD for 1601 positive clinical bottles incubated in the BacT/ALERT 3D system (BTA-3D). MethodsThe most representative microorganisms isolated from bottles incubated in both blood culture systems were divided into eight categories (in order of frequency): coagulase-negative staphylococci (CoNS), Escherichia coli, Enterobacteriaceae (other than E. coli), Staphylococcus aureus, Enterococcus spp, viridans group streptococci, Pseudomonas aeruginosa, and Candida spp. ResultsThe comparison of TTD values for the two blood culture systems strongly indicated that growth of the first five groups listed above was detected earlier with VIRTUO than with BTA-3D (p < 0.05). ConclusionsThe new VIRTUO blood culture system can reduce the TTD for more than 75% of isolated microorganisms.

Papillary fibroelastoma, unusual cause of stroke in a young man: a case report

BackgroundPapillary fibroelastoma is the third most common primary benign tumor with an incidence of up to 0.33% in autopsy series; it accounts for approximately 75% of all cardiac valvular tumors.Case presentationWe describe a rare case of a 28-Year-old man that while playing football, had a sudden onset of neurological deficit: aphasia, right hemiparesis and right facial numbness. Transthoracic echocardiography (TTE) showed a 10x10 mm mass attached to the anterior mitral valve leaflet. The patient was treated surgically for the prevention of further embolic complications. Histologic examination of the resected mass revealed a papillary fibroelastoma. It is the third most frequent primary cardiac tumor, after myxoma and fibroma, and the most common primary tumor of heart valves. Despite the benign nature of this tumor, it carries very high risk of embolic complications. The successful complete resection of the papillary fibroelastoma is curative and the long-term postoperative prognosis is excellent.ConclusionsDifferential diagnosis of cardiac masses requires clinical informations, laboratory tests, blood cultures and appropriate use of imaging modalities. Papillary fibroelastoma is a potential cause of embolic stroke in the young. The prompt surgical excision of papillary fibroelastoma is curative and the long-term postoperative prognosis is excellent.

Potential Impact of Rapid Blood Culture Testing for Gram-Positive Bacteremia in Japan with the Verigene Gram-Positive Blood Culture Test.

Background. Early detection of Gram-positive bacteremia and timely appropriate antimicrobial therapy are required for decreasing patient mortality. The purpose of our study was to evaluate the performance of the Verigene Gram-positive blood culture assay (BC-GP) in two special healthcare settings and determine the potential impact of rapid blood culture testing for Gram-positive bacteremia within the Japanese healthcare delivery system. Furthermore, the study included simulated blood cultures, which included a library of well-characterized methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) isolates reflecting different geographical regions in Japan. Methods. A total 347 BC-GP assays were performed on clinical and simulated blood cultures. BC-GP results were compared to results obtained by reference methods for genus/species identification and detection of resistance genes using molecular and MALDI-TOF MS methodologies. Results. For identification and detection of resistance genes at two clinical sites and simulated blood cultures, overall concordance of BC-GP with reference methods was 327/347 (94%). The time for identification and antimicrobial resistance detection by BC-GP was significantly shorter compared to routine testing especially at the cardiology hospital, which does not offer clinical microbiology services on weekends and holidays. Conclusion. BC-GP generated accurate identification and detection of resistance markers compared with routine laboratory methods for Gram-positive organisms in specialized clinical settings providing more rapid results than current routine testing.

Utility of cytokine, adhesion molecule and acute phase proteins in early diagnosis of neonatal sepsis.

Background and Aim:Neonatal infection, including bacterial sepsis, is a major health care issue with an annual global mortality in excess of one million lives. Therefore, this study aimed to evaluate the potential diagnostic value of C-reactive protein (CRP), E-selectin, procalcitonin (PCT), interleukins-6 (IL-6), and tumor necrosis factor-α (TNF-α) both independently and in combination for the diagnosis of neonatal sepsis in its earliest stages.Materials and Methods:A total of 320 subjects were included in this study. A prospective cross-sectional study was conducted among neonates admitted to Neonatal Intensive Care Unit at King Abdulaziz Medical City, Riyadh, KSA during January 2013 to August 2015, the study based on three study groups categorized according to clinical symptoms and blood culture result. Study groups include healthy control neonates (n = 80), clinical sepsis (CS) group (n = 80) with clinical signs of sepsis but their blood culture was negative, and sepsis group with clinical signs of sepsis and their blood culture was positive.Results:The study observed significant difference in plasma levels of CRP, IL-6, TNF-α, E-selectin, and PCT in patients group when compared with control group (P < 0.001). Furthermore, the levels are significantly different between patient groups including CS and neonatal sepsis group. Moreover, result observed significant difference in CRP and IL-6 in early onset sepsis (EOS) when compared with late onset sepsis (LOS) neonates (P < 0.001 and 0.01), respectively, while there were no significant difference in TNF-α, E-selectin, and PCT between EOS and LOS (P = 0.44, 0.27 and 0.24), respectively. Regarding biomarkers accuracy, the result showed that CRP has the best diagnostic accuracy with cutoff value of 3.6 ng/ml (sensitivity 78% and specificity of 70%). The best combination is shown with CRP and IL-6 in which sensitivity increased to 89% and specificity to 79%.Conclusion:It was concluded that infected new-born babies have a higher E-selectin, PCT, IL-6, TNF-α, and CRP compared with the neonates with CS and control. IL-6, TNF-α, and CRP should be measured in combination for mare diagnostic accuracy in neonatal sepsis. Likewise, PCT should be investigated as a part of sepsis screening for all suspected neonates.

A Novel Microfluidic Assay for Rapid Phenotypic Antibiotic Susceptibility Testing of Bacteria Detected in Clinical Blood Cultures.

BackgroundAppropriate antibiotic therapy is critical in the management of severe sepsis and septic shock to reduce mortality, morbidity and health costs. New methods for rapid antibiotic susceptibility testing are needed because of increasing resistance rates to standard treatment.AimsThe purpose of this study was to evaluate the performance of a novel microfluidic method and the potential to directly apply this method on positive blood cultures.MethodsMinimum inhibitory concentrations (MICs) of ciprofloxacin, ceftazidime, tigecycline and/or vancomycin for Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Staphylococcus aureus were determined using a linear antibiotic concentration gradient in a microfluidic assay. Bacterial growth along the antibiotic gradient was monitored using automated time-lapse photomicrography and growth inhibition was quantified by measuring greyscale intensity changes in the images. In addition to pure culture MICs, vancomycin MICs were determined for S. aureus from spiked and clinical blood cultures following a short centrifugation step. The MICs were compared with those obtained with the Etest and for S. aureus and vancomycin also with macrodilution.ResultsThe MICs obtained with the microfluidic assay showed good agreement internally as well as with the Etest and macrodilution assays, although some minor differences were noted between the methods. The time to possible readout was within the range of 2 to 5 h.ConclusionsThe examined microfluidic assay has the potential to provide rapid and accurate MICs using samples from positive clinical blood cultures and will now be tested using other bacterial species and antibiotics.