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@#<p style="text-align: justify;"><strong>Introduction:</strong> In the setting of Sepsis, Blood Culture is one of the important diagnostic tools in aiding a clinician to determine the offending pathogen. Following the Sepsis Bundle, Blood Culture is obtained at two sites before initiation of antibiotics. However, blood Cultures are one of the expensive tests wherein some clinicians find it unnecessary and costly. This study would provide more information regarding positive blood cultures among septic patients as a prognostic tool regarding the time to positivity. Reporting Time to Positivity would aid clinicians in the severity of the infection and could be used as a clinical predictor of mortality. This study investigated the optimal cutoff point of the time to positivity to predict mortality and the association between time to positivity of blood cultures with mortality among septic patients.</p><p style="text-align: justify;"><strong>Methods:</strong> This was a single-center cross-sectional study with a retrospective chart review of septic patients with positive blood cultures. The optimal cutoff point of time to positivity was determined and associated with mortality.</p><p style="text-align: justify;"><strong>Results:</strong> 405 adult in-patients with sepsis in Makati Medical Center from April 1, 2017, to April 30, 2018, were reviewed. The suggested optimal cutoff TTP is ?19.1 hours, with sensitivity 79.78%, specificity 28.48%, accuracy 39.75%, Youden's index 8.26%. The overall mortality rate is 21.98%. The mortality rate was higher in the TTP < 19.1 group at 23.91% compared to the >19.1 hours group. Predictors associated with mortality are age, liver comorbidity, genitourinary source of infection, and short TTP.</p><p style="text-align: justify;"><strong>Conclusion:</strong> A short TTP was associated with higher mortality rates. TTP can be clinically used to predict poorer outcomes. Therefore, patients with a short TTP should be monitored more closely, and appropriate antibiotics should have been initiated.</p>
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Objective:To evaluate whether the time to positive (TTP), handling time after positive alarm and turnaround time (TAT) of bacteremia blood culture can be shortened by optimizing blood culture workflow.Methods:This study was conducted retrospectively. Positive blood culture samples collected from Peking University People′s Hospital from January 1, 2014 to June 30, 2021 were analyzed in stages. In the traditional process stage of this study (2014), 502 bottles of positive blood culture samples were included in the analysis. In the first stage of process optimization (2016), the working time of staff was increased to 22:00, and 976 positive blood culture specimens were included in the analysis. In the second stage of process optimization (2018), the rapid identification process of MALDI-TOF MS was added, and a total of 1 029 bottles of positive blood culture samples were included. In the third stage of process optimization (2020) with the introduction of the new VIRTUO BACT/ALERT system. The difference of TTP, handling time after positive alarm and TAT of whole process in different stages of traditional process and process optimization were compared. All data were statistically significant when P<0.05 using rank-sum test. Results:In the traditional process stage (2014), the median quartile time of handling time after positive alarm was 55.70 (47.35, 68.45) h. In the first stage of process optimization (2016), the median quartile time of handling time after positive alarm was 47.25 (33.88, 59.96) h, and the handling time after positive alarm in the first stage of process optimization was significantly shorter than that in the traditional process stage ( Z=?10.734, P<0.001). In the second stage of process optimization (2018), the median quartile time for handling time after positive alarm was 47.18(36.41, 59.40) h, and 12.18% of the preliminary identification results of Gram-negative bacilli before 17:00 could be reported to the clinic before audit. In the third stage of process optimization (2020), the median quartile of TTP and TAT were 39.56 (21.52, 62.65) h and 78.16(64.68, 99.72) h respectively in the original BACT/ALERT 3D system. The new VIRTUO BACT/ALERT system had a median quartile of 37.03(21.08, 58.22) h for TTP and 73.41(62.88, 89.48) h for TAT. VIRTUO BACT/ALERT 3D had a significantly shorter TTP than BACT/ALERT 3D ( Z=?2.273, P=0.023), the TAT of VIRTUO BACT/ALERT system was significantly shorter than that of BACT/ALERT 3D system ( Z=?4.040, P<0.001). Conclusion:By improving the blood culture process of microbiology laboratory in many aspects and measures, the processing time of blood culture in each stage can be shortened and clinical benefits can be obtained.
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BACKGROUND: Fast identification of Candida glabrata is important, because empirical antifungal therapy for fungemia with C. glabrata and non-C. glabrata varies. We proposed an algorithm for rapid presumptive diagnosis to identify fungemia with C. glabrata using earlier or only growth from anaerobic bottles and longer time to positivity (TTP) in blood cultures. METHODS: Positivity and TTP using the BacT/Alert 3D system (bioMerieux Inc, USA) with resin bottles (FA Plus and FN Plus) were analyzed in 215 candidemia patients from June 2014 to June 2016 in a university-affiliated hospital in Korea. RESULTS: A higher proportion of earlier or only growth from anaerobic bottles was observed in C. glabrata (38.8%, 7/18) than in C. albicans (7.6%, 8/105), C. parapsilosis (10.5%, 4/138), and C. tropicalis (9.2%, 5/54) (P=0.006). The mean (±standard deviation) TTP for C. glabrata was 41.7 h (±16.3 h) compared with 26.7 h (±15.9 h) for C. albicans, 33.4 h (±8.4 h) for C. parapsilosis, and 23.1 h (±17.3 h) for C. tropicalis (P 31.4 h. CONCLUSION: This two-step algorithm in the BacT/Alert 3D system could be the basis for an initial empirical antifungal therapy for fungemia with C. glabrata prior to final identification.
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Humanos , Candida glabrata , Candida , Candidemia , Diagnóstico , Fungemia , Coreia (Geográfico) , Sensibilidade e EspecificidadeRESUMO
Objective To evaluate the application of time to positivity (TTP)in differential diagnosis of intracranial infection caused by coagulase-negative Staphylococcus (CNS).Methods One hundred and twenty-four adult patients with positive CNS isolated from cerebrospinal fluid (CSF)including 70 cases with intracranial infection and 54 cases of CSF contamination,who were admitted in Xiangya Hospital of Central South University during January to December 201 5,were retrospectively analyzed.The difference of TTP between two groups was compared,receiver operating characteristic (ROC)curve was analyzed and the area under the ROC curve (AUC)was calculated.The application of TTP in differential diagnosis of CNS infection was evaluated.SPSS 1 8.0 software was used to analyze the data.Results TTP in intracranial infection group was shorter than that in CSF contamination group [(23.5 ±7.5 )h vs. (37.6 ±1 0.5)h,t =-8.71 7,P =0.000].The AUC of TTP was 0.854.Taking the cut-off value of 27.94 h,the sensitivity,specificity,positive and negative predictive values in differentiation of two groups were 72.7%,91 .4%,90.0% and 72.2%,respectively.There were statistically differences in TTP of Staphylococcus epidermidis,Staphylococcus haemolyticus and Staphylococcus capitis between two groups (Z =-4.496,-2.322 and -2.399,respectively,P <0.05 or <0.01 ).Conclusion TTP can be used to discriminate early intracranial infection and CSF contamination caused by CNS,and also can identify intracranial infection caused by different categories of CNS.
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Objective To analyze the significance of time to positivity(TTP)of blood culture in differentiating bloodstream infection(BSI)from contamination during blood withdrawal.Methods Clinical data and TTP of blood culture in patients hospitalized in different departments from November 2013 to November 2014 were compared retrospectively,role of TTP in differential diagnosis of BSI was evaluated.Results Of 2 605 blood culture specimens,137 were positive for blood culture,78 (56.93%)of which were pathogenic bacteria and 59(43.07%) were contaminated bacteria,coagulase negative staphylococcus had the highest contamination rate(75.76%),while Escherichia coli had the lowest contamination rate(12.50%).TTP of pathogenic bacteria was shorter than that of contaminated bacteria ([13.86 ±8.19]h vs [40.72 ±20.96]h,P <0.05 ).Of pathogenic bacteria,Enterococcus had the earliest TTP ([10.20±8.00]h),followed by Escherichia coli ([11 .12 ±3.91 ]h),Staphylococcus aureus ([12.22±5.08]h),Klebsiella pneumoniae ([14.72±10.45]h),the other gram-negative bacteria([16.11 ±12.97] h),and coagulase negative staphylococci([16.42±5.74]h),fungi had the latest TTP ([29.04±3.67]h ).TTP of gram-negative bacteria was ≤16.59 h,sensitivity and specificity of BSI were 84.09% and 100.00% respectively;TTP of gram-positive bacteria was ≤20.96 h,sensitivity and specificity of BSI were 96.77% and 94.44% respec-tively.Conclusion Combination of TTP of blood culture and other clinical indications can provide reference for early differentiating isolated pathogenic bacteria from contaminated bacteria.
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Objective To determine the value of differential time to positivity ( DTTP ) of blood culture for the diagnosis of catheter-related bloodstream infection ( CRBSI ) in patients with solid tumors in intensive care unit ( ICU ). Methods A retrospective study was conducted. 615 pairs of peripheral vein blood cultures and instantaneous catheter tip blood culture of 615 patients admitted to ICU of Tianjin Medical University Cancer Institute and Hospital were collected from August 2011 to March 2014. The DTTP method and ( or ) semi quantitative culture of catheter tip were compared. CRBSI was diagnosed when both cultures were positive for the same microorganism and DTTP ≥2 hours ( 120 minutes ). The result of this procedure was compared with that of organism obtained using the semi quantitative culture of blood at catheter tip with≥15 cfu. Based on the clinical diagnosis, the reliability of two kinds of laboratory examination was compared for the diagnosis of CRBSI by plotting receiver operator characteristic curve ( ROC curve ). Results The result of 615 cases suspected of having CRBSI were analyzed during the study period. Of these, 440 episodes were excluded because cultures were negative for blood obtained through peripheral vein and central vein. Eight episodes were excluded because only peripheral vein blood culture was positive and 57 episodes were excluded because of only central vein blood culture was positive, 68 pairs of blood cultures were excluded due to the presence of multiple catheters and repeated blood withdrawals. Two cases of polymicrobial cultures were excluded from the final analysis due to the difficulty in determining the time of positive result for each individual microorganism. Ten cases in 42 cases of suspected cases of CRBSI were excluded from analysis because catheter was not removed, therefore culture from catheter tip could not be obtained. Using the DTTP method, 14 out of 17 CRBSI cases were diagnosed with DTTP≥120 minutes, while 3 cases were missed;the semi quantitative catheter tip culture was positive in 13 cases, and in 4 cases it was neglected. In 2 cases of CRBSI it was missed by both methods. The area under the ROC curve ( AUC ) of DTTP, catheter tip culture and the combination method was 0.912, 0.882 and 0.941 for diagnosis of CRBSI, respectively. Validity values for the diagnosis of CRBSI for DTTP were:sensitivity 82.35%, specificity 92.31%, positive predictive value 93.33%and negative predictive value 80.00%, and they were higher than those of the catheter tip culture method only ( 76.47%, 84.62%, 86.67% and 73.33%). The specificity and positive predictive CRBSI combination of the two methods in the diagnosis value were up to 100%, the sensitivity ( 88.24%) and negative predictive value ( 86.67%) was also increased, but no significant differences were found with DTTP method (χ2=0.00, P=1.00;χ2=0.00, P=0.98;χ2=0.00, P=0.98;χ2=0.00, P=0.98 ). Conclusions DTTP can be a valid method recommended for CRBSI diagnosis in critically ill patients with acceptable sensitivity, good specificity as well as positive predictive value. DTTP combined with other clinical symptoms can not only avoid unnecessary catheter withdrawal, but it also can help obtain the optimal treatment time and strategy.
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INTRODUÇÃO: As infecções de corrente sanguínea relacionadas com cateter (ICSRCs) apresentam impacto significativo na morbidade e na mortalidade de pacientes internados, além de elevar custos hospitalares. A utilização de equipamentos automatizados no processamento de hemoculturas gerou uma alternativa para diagnóstico de ICSRC por meio da análise da diferença de tempo de positividade (DTP) entre hemoculturas pareadas (coletadas simultaneamente) de sangue periférico e sangue de cateter. Um diagnóstico acurado e rápido dessas infecções pode otimizar as condutas clínicas e terapêuticas, poupando a retirada precoce dos cateteres. OBJETIVOS: Avaliar na rotina a DTP como ferramenta auxiliar no diagnóstico de ICSRC e determinar os principais microrganismos isolados. MÉTODOS: Foram avaliadas retrospectivamente hemoculturas coletadas no complexo do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (HC/FMUSP) de maio a agosto de 2008. Somente amostras que apresentaram DTP maior que 120 minutos foram consideradas possíveis ICSRCs pelo critério laboratorial. RESULTADOS: A seção processou 11.017 hemoculturas aeróbias durante o período de estudo; somente 5% foram coletadas de forma pareada. Destas, 148 (28%) foram positivas, sendo 9% com crescimento somente em sangue periférico, 41% somente em sangue de cateter e 50% em ambas as amostras com 88% de homologia de microrganismos identificados. A DTP apresentou valores acima de 120 minutos em 50% dos casos e os microrganismos mais isolados foram Staphylococcus aureus (22%), Candida spp. (18%), Klebsiella spp. (7%) e Enterobacter spp. (7%). CONCLUSÃO: A determinação da DTP como ferramenta auxiliar no diagnóstico de ICSRC é viável e fácil de ser executada em laboratórios de rotina com automação, porém o processo de coleta das amostras pareadas deve ser rigidamente padronizado.
INTRODUCTION: Not only do catheter related bloodstream infections (CRBSIs) have considerable impact on morbidity and mortality in hospitalized patients, but they also raise hospital costs. The use of automated equipment in blood culture processing has allowed an alternative diagnosis of CRBSI by analyzing the differential time to positivity (DTP) of paired blood cultures (collected simultaneously) of peripheral blood and catheter blood. A rapid and accurate diagnosis of these infections may optimize clinical and therapeutic management, which prevents early catheter removal. OBJECTIVES: To assess DTP as an auxiliary tool for the diagnosis of CRBSI as well as to determine the main isolated microorganisms. METHODS: We evaluated blood cultures that had previously been collected in the complex Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (HC/FMUSP) from May to August 2008. According to the laboratory criteria, only DTP higher than 120 minutes was regarded as possible CRBSI. RESULTS: During the investigation period 11,017 aerobic blood cultures were processed, from which only 5% were paired samples. One hundred forty-eight (28%) samples were positive, from which 9% showed growth in peripheral blood, 41% only in catheter blood and 50% in both blood samples with 88% homology of identified microorganisms. DTP higher than 120 minutes occurred in 50% of the cases. The most common isolated microorganisms were: Staphylococcus aureus (22%), Candida spp. (18%), Klebsiella spp (7%). and Enterobacter spp (7%). CONCLUSION: The determination of the DTP as an auxiliary tool for the diagnosis of CRBSI is feasible and easily performed in clinical laboratories with automation, although the process of paired sample collection must be rigidly standardized.
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Cateterismo Venoso Central , Técnicas e Procedimentos Diagnósticos , Infecção Hospitalar/diagnóstico , Infecções Relacionadas a Cateter/diagnósticoRESUMO
BACKGROUND: Catheter-related bloodstream infection (CRBSI) is one of the leading types of infection, with a significant morbidity and mortality rate. We evaluated the differential time to positivity (DTP) and semi-quantitative culture of catheter segments (SQCC) as a method for diagnosing CRBSI. METHODS: From January 2010 to August 2011, 155 positive paired blood cultures which had the same organism isolated from blood cultures drawn simultaneously through the central venous catheter (CVC) and the peripheral vein were included. Positive DTP represents a DTP of least 120 min earlier for the time to detection of CVC draw than that of a peripheral vein draw. We evaluated the clinical utility of DTP and SQCC for diagnosing CRBSIs, which were further divided into two groups: confirmed (either by DTP or SQCC) and non-confirmed CRBSIs (neither DTP nor SQCC positive). RESULTS: Sixty-five percent (100/155) of episodes were confirmed to CRBSIs. In CRBSIs, Gram-positive cocci accounted for 61% of cases, non-fermenting Gram-negative bacilli represented 10%, Enterobacteriaceae for 10%, yeasts for 15%, and others for 4%. Among the confirmed CRBSI cases, 22 were both positive with DTP and SQCC, 30 cases were positive with DTP only, 12 cases were positive with SQCC only, and 36 cases which did not undergo SQCC analysis were DTP positive. The sensitivities of the DTP and SQCC techniques were 88.0% (88/100) and 53.1% (34/64), respectively. CONCLUSION: The differential time to positivity was more sensitive than the semi-quantitative culture of catheter segments for the diagnosis of CRBSIs. DTP is useful for diagnosing CRBSIs without removal of the catheter.
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Catéteres , Cateteres Venosos Centrais , Enterobacteriaceae , Cocos Gram-Positivos , Veias , LevedurasRESUMO
BACKGROUND: Continuous monitoring systems have allowed determination of the time-to-positivity (TTP). We evaluated the clinical relevance of TTP in the BACTEC9240 system (Becton-Dickinson, USA). METHODS: A total of 2,354 vials of positive blood cultures were evaluated over 2 months. TTP was monitored from each of BACTEC Plus Aerobic/F (BD) or Pediatric Plus/F and Lytic Anaerobic/F bottles, and the differential time-to-positivity (DTP) for blood samples drawn simultaneously via catheter and a peripheral site was determined. RESULTS: The average TTP of the positive vials was 17.4 hr, and 79.9% and 95.2% of the vials showed positivity within 24 and 48 hr, respectively. While the average TTP values for Aeromonas hydrophila, Bacillus cereus, Acinetobacter baumannii, and Streptococcus pneumoniae were less than 10 hr, those for Candida spp., anaerobes, Propionibacterium acnes, Corynebacterium spp, Bacillus spp. other than cereus, and coagulase-negative staphylococci were 35.3, 27.0, 56.8, 45.8, 23.0, and 26.3 hr, respectively. The negative predictive values of TTP over 24 hr to predict Staphylococcus aureus among staphylococci and S. pneumoniae among alpha-hemolytic streptococci were 76.7% and 100%, respectively. Enterobacteriaceae and Enterococcus faecalis showed shorter TTP in anaerobic vials than in aerobic vials. DTP of more than 2 hr was observed for 27.8%, 72.2%, and 45.5% of S. aureus, S. epidermidis, and Candida spp. CONCLUSIONS: TTP can be used to discriminate pathogens and contaminants. The shorter TTP in anaerobic vials of certain Enterobacteriaceae and Enterococcus spp. would facilitate further identification. DTP is useful for diagnosing catheter-related bloodstream infection by S. aureus, S. epidermidis, and Candida spp.