Sets Of Blood Cultures Research Articles

The use of a diversion tube to reduce blood culture contamination: A “real-life” quality improvement intervention study

BackgroundBlood culture contamination is associated with health care costs and potential patient harm. Diversion of the initial blood specimen reduces blood culture contamination. We report results of the "real-life" clinical implementation of this technique. MethodsFollowing an educational campaign, use of a dedicated diversion tube was recommended prior to all blood cultures. Blood culture sets taken from adults using a diversion tube were defined as "diversion sets," those without, "non-diversion" sets. Blood culture contamination and true positive rates were compared for diversion and nondiversion sets and to nondiversion historical controls. A secondary analysis investigated efficacy of diversion by patient age. ResultsOut of 20,107 blood culture sets drawn, the diversion group included 12,774 (60.5%) and the nondiversion group 8,333 (39.5%) sets. The historical control group included 32,472 sets. Comparing nondiversion to diversion, contamination decreased by 31% (5.5% [461/8333] to 3.8% [489/12744], P < .0001]. Contamination was also 12% lower in diversion than historical controls [3.8% (489/12744) vs 4.3% (1,396/33,174) P = .02)]. The rate of true bacteremia was similar. In older patients, contamination rate was higher, and the relative reduction associated with diversion decreased (54.3% amongst 20-40-year-olds vs 14.5% amongst >80-year-olds). ConclusionsUse of a diversion tube in the ED reduced blood culture contamination in this large real life observational study. Efficacy decreased with increasing age, which requires further investigation.

Incidence, aetiology and temporal trend of bloodstream infections in southern Sweden from 2006 to 2019: a population-based study.

BackgroundBloodstream infections (BSI) are a public health concern, and infections caused by resistant bacteria further increase the overall BSI burden on healthcare.AimTo provide a population-based estimate of BSI incidence and relate this to the forthcoming demographic ageing western population change.MethodsWe retrieved positive blood cultures taken from patients in the Skåne region, southern Sweden, 2006-2019 from the Clinical Microbiology Department database and estimated incidence rates (IR), stratified by age (0-49, 50-64, 65-79, ≥ 80 years), sex, year, and species and described antimicrobial susceptibility for Enterobacterales.ResultsWe identified 944,375 blood culture sets, and 129,274 (13.7%) were positive. After deduplication and removal of contaminants, 54,498 separate BSI episodes remained. In total, 30,003 BSI episodes (55%) occurred in men. The overall IR of BSI was 307/100,000 person-years, with an average annual increase of 3.0%. Persons ≥ 80 years had the highest IR, 1781/100,000 person-years, as well as the largest increase. Escherichia coli (27%) and Staphylococcus aureus (13%) were the most frequent findings. The proportion of Enterobacterales isolates resistant to fluoroquinolones and third generation cephalosporins increased from 8.4% to 13.6%, and 4.9% to 7.3%, (p for trend < 0.001), with the largest increase in the oldest age group.ConclusionWe report among the highest BSI IRs to date worldwide, with a higher proportion among elderly persons and males, including resistant isolates. Given expected demographic changes, these results indicate a possible substantial future BSI burden, for which preventive measures are needed.

Verification of quality assurance for blood culture surveillance using 6 years of data from the Japan Infection Prevention and Control Conference for National and Public University Hospitals

The importance of blood culture has been widely recognized, and there is a need for monitoring to evaluate the accuracy of blood culture that reflects domestic healthcare systems. In this study, we assessed 6-year trends in blood culture quality assurance data. The Japan Infection Prevention and Control Conference for National and Public University Hospitals conducted yearly blood culture surveillance at 52 national public university hospitals from 2015 to 2020. Statistical analysis showed that comparison with the previous year showed significant differences in the number of blood cultures per 1000 patient-days in all years. The number of blood cultures per 1000 admissions was not significantly different in 2017 and 2018, but significant differences were shown in all other years. The multiple blood culture set rate was significantly different between non-pediatric inpatients and outpatients but not between pediatric inpatients and outpatients. The contamination rate did not differ significantly. For all parameters, significant differences were found when comparing 2015 and 2020. Our survey showed that although the sample number improved over time, even the most recent values for 2020 were lower than Cumitech's targets. It is difficult to assess whether these sample numbers are appropriate because target values have not been set for the various types of hospitals in Japan. Surveillance is a useful tool for monitoring quality assurance for blood culture. All parameters improved over the 6-year period, but it is necessary to establish a benchmark for evaluating optimization. We will continue to monitor quality assurance and work on setting benchmarks.

Fatal infective endocarditis early after TAVR.

A 75-year-old patient who had received Evolut R 34 TAVR prosthesis for severe aortic stenosis 2 months prior, presented for dyspnea, altered mental status and abdominal pain. Three blood cultures sets tested positive for Enterococcus faecalis. Transthoracic echocardiography was limited by a poor acoustic window, prompting for transesophageal echocardiography, which revealed an echo-free gap between the prosthesis and the posterior aortic wall suggesting the possibility of a periprosthetic abscess (Panel A). Cardiac CT found an abscess between the metal structure of the prosthesis and the noncoronary aortic sinus (Panel B, arrow and Panel C, top arrow), as well as filling defects suggesting vegetations at the level of the biological valve and of the metal structure of the prosthesis (Panel C, buttom arrow and Panel D, arrow). Two aortic pseudoaneurysms in relation to the distal extremity of the endoprosthesis’s stent were also present (Panel D and E, arrowhead). Multiorgan CT scans performed as a part of the IE imaging approach revealed multiple recent ischemic lesions in the brain (Panel F), as well as hepatic, splenic and renal infarcts (Panel G). Given the severe neurological deficit caused by the stroke, the patient was not a candidate for surgical prosthesis replacement. During the monitoring, the patient presented worsening of the symptoms and he died on Day 7 of his hospitalization. Our case emphasizes the possibility of a negative outcome after TAVR, as well as the role of imaging in the diagnosis of early infective endocarditis after TAVR.1,2

Can Blood Culture Contaminaton Cloud Fungal Positivity?

Objective: Blood culture (BC) is gold standard for diagnosis of fungemia. Contamination of BC is a major problem worldwide, since it may delay actual diagnosis. The aim of this study was to evaluate “contaminant” vials with a prolonged incubation (max 30 days) with antimicrobial supplemented media to observe any mycological growth. Materials and Methods: Routine BCs optained patients of XXX Hospital for a year period were included. Render BC System BC12-8 (Render Biotech Co. Ltd., Shenzhen, China) were used. Contaminated vials were reincubated and conventionally-inoculated weekly for four weeks total. In case of any growth, identifications were done by PhoenixTM 100 system (Becton Dickinson, MA, USA) with cornmeal tween 80 agar (RTA Laboratories, Kocaeli, Turkey). Antifungal susceptibility testing were applied with CLSI disk diffusion method. Results: 3.9% (235 sets and additional 138 vials) of total 6047 BC sets were contaminated. Only one vial from central venous catheter showed fungal growth within the first week of conventional inoculation (&gt;8th day of total incubation). The isolate was identified as Candida guilliermondii complex and susceptible to caspofungin. Latter set of this patient were positive in the 3rd day of incubation. Conclusion: International guidelines recommend

Prolonged Fever in a Child With Congenital Heart Disease and a Prosthetic Valve.

Prolonged Fever in a Child With Congenital Heart Disease and a Prosthetic Valve.

Contamination of Blood Cultures From Arterial Catheters and Peripheral Venipuncture in Critically Ill Patients: A Prospective Multicenter Diagnostic Study

Collecting blood cultures from indwelling arterial catheters is an attractive option in critically ill adult patients when peripheral venipuncture is difficult. However, whether the contamination proportion of blood cultures from arterial catheters is acceptable compared with that from venipuncture is inconclusive. Is contamination of blood cultures from arterial catheters noninferior to that from venipuncture in critically ill adult patients with suspected bloodstream infection? In this multicenter prospective diagnostic study conducted at five hospitals,we enrolled episodes of paired blood culture collection, each set consisting of blood drawn from an arterial catheter and another by venipuncture, were obtained from critically ill adult patients with cilinical indication. The primary measure was the proportion of contamination, defined as the number of false-positive results relative to the total number of procedures done. The reference standard for true bloodstream infection was blinded assessment by infectious disease specialists. We examined the noninferiority hypothesis that the contamination proportion of blood cultures from arterial catheters did not exceed that from venipuncture by 2.0%. Of 1,655 episodes of blood culture from December 2018 to July 2021, 590 paired blood cultureepisodes were enrolled, and 41 of the 590 episodes (6.9%) produced a true bloodstream infection. In blood cultures from arterial catheters, 33 of 590 (6.0%) were positive, and two of 590 (0.3%) were contaminated; in venipuncture, 36 of 590 (6.1%) were positive, and four of 590 (0.7%) were contaminated. The estimated difference in contamination proportion (arterial catheter - venipuncture) was -0.3%(upper limit of one-sided 95%CI,+0.3%). The upper limit of the 95%CI did not exceed the predefined margin of+2.0%, establishing noninferiority (P for noninferiority< .001). Obtaining blood cultures from arterial catheters is an acceptable alternative to venipuncture in critically ill patients. University Hospital Medical Information Network Center (UMIN-CTR); No.: UMIN000035392; URL: https://center6.umin.ac.jp/.

Can Prolonged Incubation of Negative Blood Cultures Show Fungal Positivity?

Objective: Standard duration of one set blood culture (BC) is a maximum of 5-7 days. The aim of this study was to evaluate “culture-negative” vials with a prolonged incubation (max 30 days) time and to observe any mycological growth. Materials and Methods: Routine BCs optained from adult patients of Balıkesir Atatürk City Hospital for a year period were included. Render BC System BC128 (Render Biotech Co. Ltd., Shenzhen, China) were used. Randomly selected vials were re-incubated for additional three weeks by conventional methods. In case of any growth, identifications were done by PhoenixTM 100 system (Becton Dickinson, MA, USA) with cornmeal tween 80 agar (RTA Laboratories, Kocaeli, Turkey). Antifungal susceptibility testing was applied with CLSI disk diffusion method. Results: A total of 6047 BC sets were obtained and randomly chosen 1040+122 negative sets (A and B groups, respectively) were included. In group A, none of them had fungal growth. In B (ongoing empiric antifungal ≤48h), only 2 sets showed significant fungal growth, which were observed in 7±2 days, and all strains were identified as C.glabrata complex and these patients were on empiric fluconazole (200 mg/day). One isolate was susceptible dose dependent, the other one was resistant for fluconazole. Latter sets of these fungemia patients showed positive signals in routine incubation period. Conclusion: Invasive fungal infections are increasingly encountered and isolation capacity and optimization of BCs are crucial. In this study, it was obviously observed that standard incubation period is satisfactory in order to detect almost all fungemia.

Dual fungemia with Fusarium and Candida in a burns patient

Case report:A 31-year-old male admitted for extensive burns developed candidemia while an inpatient. Despite intravenous anidulafungin and line exchange, he remained febrile. Multiple sets of blood cultures were repeated, and one culture bottle flagged positive after three days. Gram stain revealed the presence of blastoconidia and pseudohyphae. The initial impression was a failure of candidemia clearance.

On-site Gram staining that increases a post-test probability of an ominous infection: a case of necrotizing fasciitis caused by Vibrio vulnificus: a case report

BackgroundGram staining is a classic but standard and essential procedure for the prompt selection of appropriate antibiotics in an emergency setting. Even in the era of sophisticated medicine with technically developed machinery, it is not uncommon that a classic procedure such as Gram staining is the most efficient for assisting physicians in making therapeutic decisions in a timely fashion.Case presentationA 65-year-old Asian man with alcoholic cirrhosis complicated by esophageal varices was brought to the emergency division of Saga Medical School Hospital in early August, complaining of severe pain, redness, swelling, and purpura of the lower extremities. On physical examination he appeared in a critically ill condition suggestive of deep-seated soft tissue infection, raising a pre-test probability of streptococci, staphylococci, Vibrio sp., or Aeromonas sp. as a causative pathogen. A characteristic of his residency in an estuarine area is that raw seafood ingestion, as documented in this patient prior to the current admission, predisposes those who have a chronic liver disease to a life-threatening Vibrio vulnificus infection.Given the pathognomonic clinical features suggestive of necrotizing fasciitis, our immediate attempt was to narrow down the differential list of candidate pathogens by obtaining clinical specimens for microbiological investigation, thus inquiring about the post-test probability of the causative pathogen. The Gram stain of the small amount of discharge from the test incision of the affected lesion detected Gram-negative rods morphologically compatible with V. vulnificus. After two sets of blood culture, intravenous meropenem and minocycline were immediately administered before the patient underwent emergency surgical debridement. The next day, both blood culture and wound culture retrieved Gram-negative rods, which were subsequently identified as V. vulnificus by mass spectrometry, matrix-assisted laser desorption/ionization. The antibiotics were switched to intravenous ceftriaxone and minocycline.ConclusionThe pre-test probability of V. vulnificus infection was further validated by on-site Gram staining in the emergency division. This case report highlights the significance of a classic procedure.

Effect of the Minimum Inhibitory Concentration of Vancomycin on the Clinical Outcome of Enterococcus faecium Bacteremia.

Vancomycin (VCM) is an antibiotic widely used in the treatment of resistant bacteria. In patients with methicillin-resistant Staphylococcus aureus (MRSA) infection, the clinical outcome differs according to the VCM minimum inhibitory concentration (MIC) of isolates. However, the effect of VCM MIC on the clinical outcome is unclear for bacterial species other than MRSA. This study evaluated the relationship between the VCM MIC and clinical outcomes in patients with Enterococcus faecium bacteremia. This study included patients who had E. faecium detected in at least one set of blood cultures between April 2011 and March 2022. The study assessed the outcome according to the VCM MIC. The primary outcome was the 30-day mortality rate. Measures of interest included the initial serum concentration of VCM, MIC, the area under the curve (AUC), and the AUC over 24-48 hours (AUC24-48 h). A total of 26 patients were included in the study, of whom 5 died and 21 survived. The 30-day mortality was higher in patients with higher MICs and lower serum albumin levels. Patients with a serum albumin level <2.0 mg/dl and a MIC ≥1 μg/ml had significantly shorter survival than those who did not (p=0.013, log-rank test). The 30-day mortality rate of patients with E. faecium bacteremia is associated with the VCM MIC of E. faecium isolates and the patient's nutritional status. Patients with albumin <2 mg/dl and MIC ≥1 μg/ml may have a poor outcome and require careful clinical monitoring.

PS-R05-5: A CASE OF SEPTIC PULMONARY EMBOLISM DUE TO MITRAL VALVE ENDOCARDITIS OCCURRING EARLY IN THE INDUCTION PHASE OF HEMODIALYSIS

A 66-year-old man with end-stage kidney disease (ESKD) due to chronic glomerulonephritis who was scheduled to start hemodialysis after surgery for radiocephalic arteriovenous fistula (AVF) was admitted to our hospital because of volume overload. He developed fever and cough after an upper endoscopy was performed on the 20th hospital day. Chest CT revealed an infiltrative shadow in the right lower lung and he was diagnosed with bacterial pneumonia and treated with sulbactam/ampicillin and azithromycin. Two sets of blood cultures were negative. There were no findings suggesting infection of the AVF. His fever persisted and repeated CT on day 37 showed multiple nodule shadows along the blood vessels in the left lower lobe. We suspected septic pulmonary embolism (SPE) and transthoracic/esophageal echocardiography showed a newly developed MV regurgitation (MVR (II/IV), with a 17 mm vegetation and partial perforation. Repeat physical examination revealed nontender, small erythematous (Janeway) lesions on the toes and a new holosystolic murmur at the apex (II/VI). (The patient said he had similar lesions on his hands but they had disappeared.) Due to the accumulation of Ga-67 citrate in the peri-oral area and the MV, caries and periodontal disease were thought to be the source of infection. Infectious endocarditis (IE) was diagnosed based on modified Duke criteria. Ceftriaxone was added to cover gram-negative bacilli in the oral cavity, including HACEK (Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, Kingella). Antibacterial treatment reduced the size of the vegetation and the MVR improved. Pulmonary nodules also disappeared. Dental treatment was performed after the vegetation had almost disappeared. Three additional sets of blood cultures were also negative. There have been few reports of SPE due to left sided IE. The onset of SPE in this case may have been caused by an embolus that formed in the MV and flowed into the right sided heart via an AVF, as emboli were also found in the peripheral extremities.

Stenotrophomonas maltophilia Bacteremia: From Diagnosis to Treatment.

There are many difficulties in diagnosing and treating Stenotrophomonas maltophilia bacteremia. In this study, we aimed to evaluate "true" and "false-positive bacteremia" and assess mortality risk factors and the impact of different treatment regimens. Hospitalized adult patients with S. maltophilia-positive blood cultures were assessed by a two-stage analysis. First, the clinical significance of blood cultures was assessed, and patients were divided into "true" and "false-positive bacteremia" groups. Then, excluding false positives, we analyzed the antimicrobial regimens and the factors associated with 28-day mortality in true bacteremia cases performing univariate and multivariate analyses. The study included 127 out of 138 patients with S. maltophilia bacteremia. True bacteremia was identified in 51.2% and false-positive bacteremia in 48.8% of patients. In the true bacteremia group, hypotension, nosocomial bacteremia, concomitant infections, a source of bacteremia, two positive blood culture sets, and 28-day mortality were more common. The 28-day mortality was 50.7% among true bacteremia cases. In multivariate analysis, age and solid tumor were the independent predictors of 28-day mortality. Early effective antimicrobial therapy and different antimicrobial regimens, including trimethoprim-sulfamethoxazole (SXT), fluoroquinolones (FQs), and tigecycline (TGC), did not have any significant impact on survival. Patients with S. maltophilia bacteremia should first be assessed regarding clinical significance. Clinical findings, the presence of multiple positive blood culture sets and the primary sources of bacteremia are useful parameters while discriminating true from false-positive bacteremia. Patients with advanced age and solid tumors should be followed carefully in terms of mortality. Antimicrobial regimens, including SXT, FQs, or TGC, can be preferred in patients with S. maltophilia bacteremia considering antimicrobial resistance and adverse effects or toxicity.

1817. Characteristics and Outcomes in Patients with Staphylococcus lugdunensis Bacteremia Compared with Staphylococcus aureus and Staphylococcus epidermidis Bacteremia

Abstract Background Staphyococcus lugudnensis (SL) is a coagulase negative Staphylococcus species with a potential to cause invasive infection. Few studies have evaluated characteristics and outcomes of SL bacteremia (SLB) compared with Staphylococcus aureus (SA) and Staphylococcus epidermidis (SE). Methods We performed a single center retrospective case-control study of patients &amp;gt; =18 years of age with SLB with at least two sets of positive blood cultures at Kyoto University Hospital, Japan from January 2005 to December 2021. Patients who had SA bacteremia (SAB) with at least one set of positive blood culture and those who had SE bacteremia (SEB) with at least two sets of positive blood cultures were randomly selected in a 1:5:5 (SL:SA:SE) ratio during the same period. Characteristics and clinical outcomes of SLB were compared with those of SAB and SEB. Results A total of 24 patients with SLB, 120 patients with SAB, and 120 patients with SEB were included. Patients’ median age (interquartile range) was 69 (60, 75), 68 (49, 77) and 65 (51, 73) in order of SL, SA, and SE. The rate of hospital-acquired infection in SL was similar to that of SA (54% vs 64%; p=0.86), lower than that of SE (54% vs 91%; p&amp;lt; 0.01). Rates of methicillin resistance and intravascular catheterization were higher in SE (83% and 92%, respectively). Patients with SLB were more likely to be on hemodialysis (25%). Rates of polymicrobial bacteremia and blood cancer was lower in SA (7% and 8%, respectively). Echocardiography was done for 14 patients in SL, lower than in SA (58% vs 82%; p=0.01). The rate of infective endocarditis (IE) (primary and secondary) was not significantly different among three groups (SL 8.5%, SA 6.5%, SE 2%). There was no significant difference in rate of metastatic lesions between SL and SA (17% vs 20%, p=0.9), statically lower in SE than in SL (17% vs 4%; p&amp;lt; 0.01). Seven-day mortality was similar between SL and SA (8% vs 7%; p=0.77), lower in SE than in SL (8% vs 0.5%; p=0.02). Thirty-day mortality in SL was not significantly different in other groups (SL 17%, SA 18%, SE 10%). Conclusion The rates of metastatic lesions and 7-day mortality in SL were similar to that of SA, higher than that of SE. Appropriate evaluation and treatment that are recommended for SAB may be warranted for patients with SLB. Disclosures All Authors: No reported disclosures.

1858. Sequential Time to Positivity as a Prognostic Indicator in Staphylococcus aureus bacteremia

Abstract Background The role of sequential blood culture time to positivity (TTP) as a surrogate marker for bacterial load and as a prognostic indicator in S. aureus bacteremia (SAB) is not well established in the literature. Methods We performed a single healthcare system, multi-site, retrospective review of adult patients with positive blood culture for S. aureus between January 2019 and December 2019. Sequential TTP was defined as the TTP of the first subsequent blood cultures obtained from patients with SAB for at least 24 hours. We adapted the previously described TTP ratio of &amp;lt; 1.5 as the cut-off for study groups. Infective endocarditis (IE) was defined according to modified Duke’s criteria. High-grade bacteremia was defined as the growth of the organism in two or more sets of blood cultures or growth in &amp;gt;50% of all bottles collected. Descriptive, comparative statistics and survival analysis were performed using Python 3 and IBM SPSS Statistics for Windows, Version 27.0. Armonk, NY: IBM Corp. Results A total of 602 patients with SAB were identified, and 186 patients who met the study criteria were included. Sixty-nine patients (37%) were female, and the mean age was 63.6 years. Patients with initial TTP &amp;lt; 12 hours had higher 30-day and 90-day mortality than those with initial TTP ≥ 12 hours. Patients with TTP ratio of &amp;gt; 1.5 had higher rates of cardiac prosthetic device (30 [26.1%] vs. 9 [12.7%], p = .03) and high-grade bacteremia (106 [92.2%] vs. 56 [78.9%], p = .01). In univariate analysis, history of myocardial infarction, cardiac prosthetic device, and findings of high-grade bacteremia and native valve vegetation in echocardiogram were significant predictors for a TTP ratio of &amp;lt; 1.5. In multivariate analysis, native valve vegetation (OR 2.4; 95% CI 1.2-4.84), and high-grade bacteremia (OR, 0.3; 95% CI, 0.13- 0.77) were independent predictors (Table 1 and 2). No differences in 30- day or 90-day survival based on the TTP ratio were seen (Figure 1). Figure 1.Kaplan-Meier (KM) curves and log rank test results based on time to positivity (TTP) of initial blood cultures and TTP ratio of sequential to initial blood culture The X-axis represents the days elapsed from the initial blood culture collection. Number of patients at risk and events are given below the x-axis for each group. 30-day and 90-day survival rates were significantly lower in patients with initial TTP of &amp;lt; 12 hours compared with those with ≥ 12 hours. There were no statistically significant differences in survival based on TTP ratio. Conclusion In patients with SAB, a second TTP to first TPP ratio of &amp;gt; 1.5 was associated with higher rates of presence of the cardiac prosthetic device and high-grade bacteremia. Initial TTP &amp;lt; 12 hours was associated with lower survival; however sequential TTP ratio didn’t predict mortality. Disclosures All Authors: No reported disclosures.

1821. Clinical Characteristics of Staphylococcus aureus Bacteremia with the Skip Phenomenon: a Case Control Study.

Abstract Background Staphylococcus aureus bacteremia (SAB) is one of the most common causes of persistent bacteremia, which is associated with complicated disease and poor clinical outcome. “The skip phenomenon (SP)” was recently proposed concept which might exhibit fluctuating blood culture positivity, but its clinical significance remained to be clarified. The aim of the study was to evaluate the clinical characteristics of SAB with the SP. Methods This is a retrospective case-control study conducted at 1141-bed university hospital during 2006-2021. Adult inpatients with more than 3 days of SAB were included. Cases were patients with SP, and controls were the rest of the patients. Duration of bacteremia was defined as bacteremic days under active antibiotic therapy counting the first day as day 1. SP was defined as at least 1 day of negative blood cultures following documented S. aureus bacteremia and preceding recurrence of a positive blood culture, which was taken within 14 days from last positive culture. Patient characteristics including medical comorbidity, implanted hardware, and focus of infection were reviewed. Results Of the 149 patients, 17 (11.4%) had the SP. A total of 20 skip phenomenon episodes among 17 cases were observed. Three patients had 2 episodes of SP. Of the 20 episodes of the SP, 7 (35.0 %) were confirmed with single set, and 13 (65.0 %) were confirmed with 2 sets of negative blood culture. The median interval from first positive blood culture to first SP episode in each case was 7 days (interquartile range [IQR], 6-16 days). Of 20 episodes of SP, 18 (90.0 %) were accompanied with fever as an indication for taking blood culture. The cases (n=17) were more likely than controls (n=132) to have a longer duration of bacteremia (median [IQR], 14 [11–36] days, vs 4 [3–7] days; p &amp;lt; 0.001), and diabetes mellitus (52.9 % vs 25.0 %, p=0.023). There was no significant difference in deep-seated infection (64.7 % vs 48.5 %, p=0.303), methicillin resistance rate (76.5 % vs 50.0 %, p=0.068), and 90-day mortality (17.6 % vs 27.3 %, p=0.561) between cases and controls. Conclusion Our findings suggest that we should consider to take blood culture repeatedly when clinically indicated, even if we confirmed the negativity once before. Disclosures All Authors: No reported disclosures.

Time to positivity of Corynebacterium in blood culture: Characteristics and diagnostic performance.

The presence of Corynebacterium in blood samples can indicate true bacteremia or contamination, thus complicating the diagnosis of true bacteremia. We aimed to evaluate the usefulness of time to positivity (TTP) in diagnosing true bacteremia and contamination in cases where Corynebacterium was isolated from blood samples. We compared the TTP of the true-bacteremia group (n = 77) with that of the contamination group (n = 88). For the true-bacteremia cases that had only one set of positive blood cultures (n = 14), considering clinical and bacteriological data, additional cultures were performed on blood or other specimens. The same Corynebacterium spp. as in blood were isolated from these specimens. Receiver operating characteristic curves were generated, and the sensitivity and specificity of TTP were calculated for diagnosing true bacteremia. The median TTP of the true-bacteremia group (26.8 h) was shorter than that of the contamination group (43.3 h) (P < 0.0001). When considering TTP ≤ 25.0 h as true bacteremia, the sensitivity and specificity were 44.2% and 95.5%, respectively. Moreover, when considering TTP ≤ 69.4 h as true bacteremia, the sensitivity and specificity were 96.1% and 20.5%, respectively. Among the true-bacteremia groups with one set of positive blood cultures (n = 14), no case exhibited a TTP > 69.4 h. Only three cases showed TTP ≤ 25.0 h in the true-bacteremia group with one set of positive blood cultures. TTP > 69.4 h is likely to indicate contamination and may be useful to exclude true bacteremia in cases with one set of positive blood cultures. Meanwhile, diagnosing true bacteremia using the threshold of TTP 25.0 h would be difficult. Therefore, the clinical and bacteriological data are important for diagnosing bacteremia, especially in cases with TTP ≤ 69.4 h.

Abstract 14124: Acute Mitral Regurgitation With Chronic Endocarditis in Type I Osteogenesis Imperfecta

Case Presentation: A 45-year-old man with history of Type I osteogenesis imperfecta (OI) presented with severe shortness of breath and worsening bilateral lower extremity edema for 6 weeks. Paternal family history was significant for Type I OI with early deaths in affected females. Physical examination revealed a distressed man with blue - gray sclerae and jugular venous distention. Cardiopulmonary examination was remarkable for tachycardia, grade IV holosystolic murmur radiating to the axilla, bilateral lung crackles with decreased air entry on the lower lung fields and pitting pedal edema up to mid thighs. TTE and TEE were significant for severe eccentric posterior MR with multiple vegetations versus ruptured chordae and normal systolic function. He underwent an emergency mitral valve replacement complicated by post-operative severe AR requiring redo sternotomy with aortic valve replacement. Histologically, aortic valve leaflets were suggestive of chronic endocarditis with dual negative sets of blood cultures drawn since admission. He was eventually discharged home after an intense cardiac rehabilitation with appropriate follow ups. Discussion: OI is a rare hereditary connective tissue disorder affecting the production of Type I collagen due to mutations in COL1A1 and COL1A2 genes. Although lesser known, OI valvulopathy is typically limited to the left sided structures, for unknown reasons, with the most common valvular anomaly being AR followed by MR. Despite the dramatic cardiac involvement in our patient and known mortality risk associated with surgical intervention, prompt evaluation and early intervention led to a successful outcome.

Emergent Off-Label TAVR for Native Aortic Valve Endocarditis.

A 76-year-old-male transferred to our center with severe breathlessness (New York Heart Association class III-IV). He was afebrile, hypoxic, and tachycardic with a wide pulse-pressure. Chest auscultation revealed a systolic and early diastolic murmur. Two weeks prior to admission, he reported severe cellulitis treated with intravenous antibiotics. Transthoracic echocardiogram demonstrated severe aortic valve (AoV) stenosis and evidence of AoV disruption with mobile vegetations and severe aortic regurgitation (AR) in keeping with plausible infectious endocarditis (IE). Following 3 sets of blood cultures, we treated the patient with intravenous antibiotics and diuretics. Blood cultures were negative, likely due to previous antibiotics treatment. Due to the acute decompensation, he underwent early heart team discussion with a view to urgent surgical AoV replacement. This case example suggests that TAVR with cerebral protection might be a safe treatment option in inoperable patients with AoV IE.

ODP451 A Case of Papillary Thyroid Cancer Presenting with Marantic Endocarditis and Recurrent Stroke

Abstract Marantic endocarditis or non-bacterial thrombotic endocarditis (NBTE) is characterized by the presence of vegetations on cardiac valves, which consist of fibrin and platelet aggregates and are devoid of inflammation or bacteria. The hypercoagulable state associated with malignancy is well known to be associated with NBTE. Here we report a rare case of Papillary Thyroid Cancer presenting with Marantic Endocarditis and Recurrent Stroke. A 52-year-old lady, with medical background of hypertension, presented to the Emergency Department with history of sudden onset of difficulty in speaking for 3 days. On examination she had slurred speech and tongue deviation to the right side. Neurological examination was otherwise normal. Imaging revealed left frontal, right frontal and left cerebellar infarcts. Transthoracic Echocardiogram showed a large, highly mobile vegetation 18 mm in size, attached to the posterior mitral valve leaflet as well as severe Mitral Regurgitation. She was diagnosed as a case of Cardioembolic ischemic stroke due to endocarditis. She completed a course of empiric antibiotic therapy. However, her blood cultures and fungal culture revealed no growth. After 5 years, she again presented to the hospital with acute stroke. Trans esophageal Echocardiography now revealed multiple filamentous vegetations on the atrial surface of mitral valve, largest measuring 20 mm×4 mm. Her inflammatory markers were negative and 3 sets of blood cultures were again negative. A question was raised, as to whether the filamentous masses represent prolapsing ruptured chordae tendinae rather than vegetations. FDG PET-CT scan was thus performed and revealed: Left thyroid lobe focal uptake seen with an FDG-avid left parajugular lymph node. Ultrasound neck was then performed, which showed bilateral thyroid nodules with high suspicion ultrasound pattern per American Thyroid Association: ill-defined nodule seen in the lower pole measuring 8×8×7 mm with multiple foci of macrocalcification. Thyroid function tests were normal. Ultrasound guided thyroid fine needle aspiration (FNA) biopsy of the left thyroid nodule was performed. The cytology report was consistent with papillary thyroid carcinoma. She is planned for total thyroidectomy, after undergoing mitral valve replacement surgery. This case illustrates one of the paraneoplastic syndromes associated with thyroid cancer. A hypercoagulable state has been observed in several types of thyroid cancer, although the pathogenesis has not been well studied. The etiology of cancer-associated coagulopathy is complex, related to an imbalance in the hemostatic system and abnormal levels of coagulation factors. Further studies on the occurrence of thrombosis in different types of thyroid cancer would help to inform clinical practice in the management of thyroid cancer, including the need for anticoagulation in certain situations. Presentation: No date and time listed