Sets Of Blood Cultures Research Articles

The Effect of a Care Bundle on the Rate of Blood Culture Contamination in a General Intensive Care Unit

Background/objectives: Blood culture (BC) contamination is a frequent problem which leads to increased laboratory workload, inappropriate use of antibiotics and the associated adverse events, and increased healthcare costs. This study prospectively examined the effect of a care bundle on BC contamination rates in a high workload ICU. Results: During the study, in total, 4236 BC vials were collected. After the intervention, the BC contamination rate decreased significantly from 6.2% to 1.3%. The incidence rate of contaminated BC sets was significantly lower following the intervention: 0.461 vs. 0.154 BC sets per 100 ICU bed-days. Overall compliance with the BC care bundle increased dramatically from 3.4% to 96.9%. Methods: We performed a before–after study in a general ICU from January 2018 to May 2019, with the intervention starting on November 2018. Blood culture sets were classified as positive, contaminated, indeterminate, and negative. We used bivariate and interrupted time series analysis to assess the effect of the intervention on BC contamination rates and other BC quality indicators. Conclusions: The BC care bundle was effective in reducing BC contamination rates and improving several quality indicators in our setting. The indeterminate BC rate is an important but understudied problem, and we suggest that it should be included in BC quality indicators as well. A significant limitation of the study was that the long-term effect of the intervention was not assessed.

A Five-Bundle Intervention to Improve Blood Culture Use in a Tertiary Hospital in Romania

Objectives: The aims of this study were to evaluate the efficacy of a five-bundle intervention and to decrease the number of cases in which only one set of blood cultures is collected prior to starting antimicrobials. Methods: The study group consisted of the two hospital wards that have the highest collection rate (120 blood cultures/1000 patient days and 121.4 blood cultures/1000 patient days, respectively), and the control group consisted of the other three adult wards. The collection protocol was changed, and a bundle of five measures was introduced: one-on-one discussions with the nurses, 2% chlorhexidine in 70% alcohol for disinfection, ensuring the use of sterile gloves, sterile wipes, a checklist for the materials needed, and a copy of the collection protocol. The impact of these changes was followed over a 5-month period. Results: Prior to the intervention, the contamination rate was higher in the control group (6.5%) versus the study group (4%), p = 0.00578. The before–after analysis revealed a significantly reduced contamination rate in the control group (4.6% vs. 6.5% p = 0.0099), but it was above the one obtained in the study group (3.1% vs. 4%, p = 0.1635). The number of infectious episodes in which one blood culture set was collected decreased significantly in the study group (77/311 vs. 139/456, p = 0.041). Conclusions: The intervention decreased the contamination rate and the number of infectious episodes in which one blood culture set is collected.

P17 Infectious sacroiliitis: an uncommon septic arthritis

Abstract Introduction Infectious sacroiliitis, an infection of the sacroiliac joint, can cause severe morbidity if not promptly treated. Staphylococcus aureus is a common pathogen, especially problematic in patients on chronic hydrocortisone therapy due to its immunosuppressive effects. This case report discusses the diagnosis and treatment challenges of infectious sacroiliitis in such immunocompromised patients, highlighting the necessity of a minimum six-week targeted antibiotic regimen to ensure bacterial eradication and prevent relapse. The report emphasises aggressive and sustained treatment for optimal outcomes in these vulnerable patients. Case description A 47-year-old man was admitted with fever, constant feeling of tiredness, and severe right-sided gluteal pain radiating to the right lower extremity, worsening with movement. He has a history of ACTH deficiency, managed with 25 mg of oral hydrocortisone daily. Examination revealed skin eczema, tenderness in the right gluteal region, and an inability to flex the right hip. His temperature was 39 °C, and CRP levels were over 400 mg/L (normal < 5 mg/L). Two sets of blood cultures showed Staphylococcus aureus. Echocardiogram ruled out of infective endocarditis. An MRI of the lumbar spine showed edema in the right posterior paraspinal muscles at L4, while a CT scan of the abdomen and pelvis revealed fat stranding around the second sacral vertebra and significant inflammation in the right iliacus and distal psoas muscles. The patient was treated with 21 days of intravenous flucloxacillin, resulting in negative blood cultures and improved inflammatory markers, leading to discharge. One week later, he was readmitted with severe gluteal pain and fever. Blood cultures again showed Staphylococcus aureus. A repeat MRI indicated an abnormal signal around the right sacroiliac (SI) joint, with extensive edema and swelling in the right gluteal, iliacus, posterior paraspinal, and obturator muscles, suggesting sacroiliitis. The patient received six weeks of intravenous flucloxacillin. After this extended antibiotic therapy, his pain and fever resolved, laboratory parameters normalised, and blood cultures were negative. Discussion Bacterial infection is a serious cause of arthritis, with infective sacroiliitis being particularly rare, accounting for just 1-2% of all septic arthritis cases. Diagnosing this condition can be challenging despite clear symptoms, often leading to delays. This case highlights several important aspects of managing severe musculoskeletal infections. Firstly, it emphasises the need for a comprehensive diagnostic approach, utilising blood cultures, imaging, and echocardiography to precisely identify the source and extent of the infection. Treating deep-seated musculoskeletal infections is especially challenging in patients with underlying conditions which can complicate the clinical picture and impact immune response. The recurrence of infection despite initial appropriate antibiotic therapy suggests the need for prolonged and potentially more aggressive antimicrobial treatment. Close monitoring for complications or recurrence is essential. The decision to restart IV flucloxacillin and extend the antibiotic course to at least six weeks represents a strategic adjustment based on clinical progression and imaging results. Given that the patient is currently on standard hydrocortisone therapy for ACTH deficiency, transitioning to modified-release hydrocortisone therapy may be a better option as it more closely mimics the circadian rhythm of glucocorticoids, normalises the immune cell profile, and reduces the incidence of recurrent infections. This case underscores the necessity for clinicians to remain vigilant for recurrent infections, considering extended or repeated imaging and microbiological studies in patients not responding as expected to initial therapy. It also highlights the importance of individualised treatment plans, especially for patients with complex medical histories and comorbidities, to achieve optimal clinical outcomes. Key learning points • Diagnostic challenges: Infectious sacroiliitis is rare and difficult to diagnose, requiring comprehensive approaches including blood cultures, imaging and echocardiography. • Immunocompromised patients: Patients on chronic hydrocortisone therapy are at higher risk for infections like sacroiliitis due to immunosuppression. Modified hydrocortisone may represent a superior option, as it more closely mimics the physiological circadian rhythm of glucocorticoids, normalises the immune cell profile, and reduces the incidence of recurrent infections. • Rare disease: Infectious sacroiliitis is a rare and often overlooked condition that requires a high index of suspicion for accurate diagnosis. Early recognition and prompt treatment are crucial to prevent serious complications and improve patient outcomes. • Prolonged treatment: Initial antibiotic therapy may lead to temporary improvement, but extended antimicrobial regimens (at least six weeks) are often necessary to prevent relapse. • Relapse management: The recurrent of symptoms and positive cultures necessitates vigilant monitoring and possibly more aggressive and prolonged antibiotic treatment. • Individualised care: Effective management of deep-seated infections in patients with complex medical histories requires tailored treatment plans and ongoing assessment to achieve optimal outcomes.

A-290 Prevalence and Antimicrobial Resistance Pattern of Microorganisms Recovered From Bloodstream Infections From Public Hospitals of São Paulo City, Brazil

Abstract Background Nosocomial Bloodstream Infections (nBSI) are an important cause of morbidity and mortality. Brazilian studies concerning bloodstream infections are important tools that can bring specific issues related to antimicrobial resistance. The objective of this study was to describe the frequency and antimicrobial susceptibility profile of bacterial isolates from BSI in patients admitted to public hospitals in 2022 and 2023. Methods This study was a retrospective analysis from 12 hospitals (January 2022 to December 2023) based on BSI isolates laboratory data detected by the clinical microbiology department of a medical diagnostic laboratory. The identification and susceptibility tests were performed using MALDI-TOF mass spectrometry (Vitek MS) and Vitek®2 systems, according to the manufacture’s recommendations. Coagulase Negative Staphylococci (CoNS) BSI was only considered in the presence of at least two sets of positive blood cultures with the same organism. Results During the period (January 2022 to December 2023) a total of 19,588 microorganisms isolated from BSI were obtained from 12 hospitals. The frequency of organism group was Gram-positive (10,707; 54.7%), Gram-negative (7,874; 40.2%), yeasts (961; 4.9%) and filamentous (46; 0.2%). The order of prevalence (top ten) organisms was CoNS (5,149; 26.3%); Staphylococcus aureus (2,769; 14.1%); Klebsiella spp. (2,355; 12.0%); Escherichia coli (1,301; 6.6%); Acinetobacter spp. (1,293; 6.6%); Streptococcus spp. (1,125; 5.7%); Enterococcus spp. (1,112; 5.7%); Candida spp. (937; 4.8%); Pseudomonas spp. (749; 3.8%) and Proteus spp. (553; 2.8%). Extended spectrum beta-lactamase rates for E. coli and Klebsiella pneumoniae were 31.6% (268/848) and 74.9% (1027/1371), respectively. The resistance to carbapenems was detected mainly in 74.1% (661/892) of Acinetobacter spp. isolates, 60.7% (832/1371) of Klebsiella pneumoniae; 24.5% (114/465) of P. aeruginosa; 9.7% (34/349) of Proteus spp. and 1.4% (12/828) of Escherichia coli. Antimicrobial resistance was observed mainly in 87.2% of CoNS (2831/3247) and 44.5% of S. aureus (743/1669) to methicillin; 22.9% (146/637) of Enterococccus spp. to vancomycin. Conclusions The frequency of Klebsiella spp. isolates from nBSI has progressively increased and effective infection control measures should be taken to prevent them from spreading. The rates of antimicrobials resistance reported for Klebsiella pneumoniae, Acinetobacter spp., CoNS, S. aureus and Enterococcus spp. reinforce the high resistance rates to antimicrobials in São Paulo city.

Validity of reducing blood culture incubation time for the BD BACTEC FX blood culture system considering microbiological and clinical aspects

IntroductionA blood culture (BC) test is vital for diagnosing bacteremia in clinical practice. Although incubation time varies among automated BC systems, 4–5 days is deemed to be sufficient time for the BD BACTEC FX blood culture system. This study compared the clinical and microbiological characteristics of true-positive BC samples on day 5 with those within 4 days to reduce missed true bacteremia cases. MethodsWe conducted a retrospective study of blood cultures from hospitalized patients between April 2020 and April 2023 at a tertiary care hospital in Japan. ResultsIn total, 12,342 BC sets were collected from 6,567 patients. Gram-positive bacilli other than Bacillus spp. and Corynebacterium spp., non-albicans Candida, and yeasts other than Candida spp. were detected more frequently in BC-positive patients on day 5 than in those within 4 days. The gastrointestinal tract was the portal of entry more frequently on day 5 than within 4 days (25 % vs. 4 %, p = 0.006). ConclusionA 4-day incubation period is sufficient for the BD BACTEC FX blood culture system under routine conditions. However, a 5-day incubation period may be warranted when low pathogenicity is suspected or the gastrointestinal tract is suspected as the portal of entry.

Clinical predictors of hospital-acquired bloodstream infections: A healthcare system analysis.

This study was performed to identify patient factors associated with hospital-acquired bloodstream infections (HABSI) to guide blood culture collection and empiric antibiotic therapy. A retrospective case-control study reviewed the medical records of 350 patients admitted to our health system from September 2017 to April 2020. The patients were 18 years and older and had at least one set of new positive non-contaminant blood cultures collected after 48 hours of admission, defined as HABSI. We developed clinical variables through a literature review associated with it. Univariate relationships between each variable and bacteremia were evaluated by chi-square test. A predictive model was developed through stepwise multivariate logistic regression. The univariate analysis and stepwise regression analysis showed that temperature >100.4° F (OR: 1.9, CI 1.1 to 3.4), male sex (OR: 1.8, CI 1.0 to 3.0), and platelet count <150,000/µL (OR: 1.8, CI 1.0 to 3.2) were statistically associated with a positive blood culture. This model helps identify patients with clinical characteristics associated with the likelihood of HABSI. This model can help guide the appropriate initiation of empiric antibiotics in clinical situations and assist with antibiotic stewardship.

Proton-Pump Inhibitors and Risk of Bloodstream Infection without an Identifiable Source: a Hospital-Based Case-Control Study.

The association between proton-pump inhibitor (PPI) use and systemic infections caused by bacterial translocation is unclear. This study aimed to investigate whether patients receiving PPI therapy have a higher risk of bloodstream infections (BSI) without an identifiable source of infection. We conducted a hospital-based case-control study which enrolled all patients aged 20 years and older who were hospitalized in Ichinomiya Nishi Hospital with BSI confirmed by two sets of positive blood cultures in 2019. Patient data were collected from medical records, and the bacterial translocation-type (BT-type) BSI group was defined as patients with BSI without an identifiable source of infection, whereas those with a BSI from an identifiable source were assigned to the control group based on the diagnostic criteria for each infectious disease. Data from 309 patients, including 66 cases and 243 controls, were analyzed. Compared with PPI non-users, PPI users had a 2.4-fold higher risk of developing BT-type BSI after controlling for potential confounders (adjusted odds ratio: 2.41, 95% confidence interval: 1.29-4.51, P = 0.006). In conclusion, PPI use is associated with a higher risk of BSI without an identifiable source; therefore, PPI use might increase the risk of BSI secondary to bacterial translocation.

Yield of repeat blood cultures in acute myeloid leukemia patients with febrile neutropenia and bacteremia following allogeneic hematopoietic stem cell transplant.

This study explored the efficacy of repeat blood cultures in bacteremic acute myeloid leukemia (AML) patients following allogeneic hematopoietic stem cell transplantation (HSCT). This was a retrospective study of AML patients who experienced febrile neutropenia (FN) and bacteremia following HSCT at the Taussig Cancer Center from January 1, 2019, to December 31, 2022. The primary endpoint was the rate of positive repeat blood cultures following initial positive blood culture. Fifty patients were included in the study. There were 50 occurrences of FN with positive initial blood cultures that were diagnosed following HSCT. Fifty initial sets of blood cultures and 96 sets of repeat blood cultures were drawn between the 50 occurrences of FN. Twelve of 96 (12.5%) repeat blood culture sets were positive for a pathogen, which occurred over nine of 50 (18.0%) episodes of FN. Three of 96 (3.2%) repeat blood culture sets grew a pathogen that differed from the pathogen that grew in the preceding positive blood culture. Among bacteremic AML patients in the post-HSCT period, the yield of repeat blood cultures for detecting previously detected and new pathogens was low.

Utility of shaking chills as a diagnostic sign for bacteremia in adults: a systematic review and meta-analysis

BackgroundAccurate prediction of bacteremia is essential for guiding blood culture collection and optimal antibiotic treatment. Shaking chills, defined as a subjective chill sensation with objective body shivering, have been suggested as a potential predictor of bacteremia; however, conflicting findings exist. To address the evidence gap, we conducted a systematic review and meta-analysis of studies to assess the diagnostic accuracy of shaking chills for predicting bacteremia among adult patients.MethodsWe included studies reporting the diagnostic accuracy of shaking chills or chills for bacteremia. Adult patients with suspected bacteremia who underwent at least one set of blood cultures were included. Our main analysis focused on studies that assessed shaking chills. We searched these studies through CENTRAL, MEDLINE, Embase, the World Health Organization ICTRP Search Portal, and ClinicalTrials.gov. Study selection, data extraction, evaluation for risk of bias, and applicability using the QUADAS-2 tool were conducted by two independent investigators. We estimated a summary receiver operating characteristic curve and a summary point of sensitivity and specificity of the index tests, using a hierarchical model and the bivariate model, respectively.ResultsWe identified 19 studies with a total of 14,641 patients in which the accuracy of shaking chills was evaluated. The pooled sensitivity and specificity of shaking chills were 0.37 (95% confidence interval [CI], 0.29 to 0.45) and 0.87 (95% CI, 0.83 to 0.90), respectively. Most studies had a low risk of bias in the index test domain and a high risk of bias and a high applicability concern in the patient-selection domain.ConclusionsShaking chills are a highly specific but less sensitive predictor of bacteremia. Blood cultures and early initiation of antibiotics should be considered for patients with an episode of shaking chills; however, the absence of shaking chills must not lead to exclusion of bacteremia and early antibiotic treatment.

E031 Retinal vasculitis with Libman-Sacks endocarditis as presenting features of a systemic lupus erythematosus with antiphospholipid antibody syndrome patient

Abstract Background/Aims Ocular manifestations of systemic lupus erythematosus (SLE) are rarely reported at the time of disease onset. Retinal vasculitis is usually associated with the active generalised disease. We report a case of a 22-year-old lady who was diagnosed with SLE with antiphospholipid antibody syndrome (APS) as the initial presentation of retinal vasculitis and Libman-Sacs endocarditis. Methods A 22-year-old lady with a background history of benign hypermobility spectrum disorder, presented to the eye casualty with a 4-week history of right-sided visual disturbances and was diagnosed with retinal vasculitis associated with uveitis, central retinal vein occlusion with multiple emboli in the retinal artery of the right eye and a single embolus in the left eye. In terms of family history, both father and brother were diagnosed with spondyloarthropathy, and the maternal uncle had Sjogren’s syndrome. She was then referred to the medical team for proper evaluation. On query, she mentioned photosensitive rash on her face getting worse in sunlight, a history of Raynaud’s phenomenon, significant hair loss, and one miscarriage before the 10 weeks of gestation. On examination, mild alopecia and a faint butterfly rash on the face were noted. Cardiac auscultation revealed pansystolic murmur. The rest of the systemic examinations were unremarkable. Results The blood test showed thrombocytopenia (130 u/L), positive antinuclear antibody (1:80, speckled pattern) with anti-double stranded DNA (26 IU/L), low complement (C3-0.74, C4- 0.12), markedly raised anticardiolipin antibody IgG (2016 u/ml), anti beta 2 glycoprotein 1 IgG ( &amp;gt;6100 u/ml) including presence of lupus anticoagulant. Her urinary protein creatinine ratio was 66mg/mmol. 3 sets of blood cultures came back negative. Transthoracic echo showed vegetation on the posterior mitral valve leaflet (0.95x 1.2cm) with moderate mitral regurgitation while transesophageal echo additionally found the possibility of perforation at the junction of leaflets of the mitral valve which was later confirmed by cardiac magnetic resonance imaging (MRI). The head MRI scan did not show any central nervous system abnormality. She was initially treated with 500mg intravenous methylprednisolone for 3 days followed by 20mg oral prednisolone daily with gradual tapering. Hydroxychloroquine and mycophenolate mofetil were added. Her case was discussed in the cardiology multidisciplinary team meeting and an opinion from the cardiothoracic surgery was taken to consider valve replacement in the future. Due to aspirin allergy, only warfarin was considered for APS. She had 2 sessions of pan-retinal photocoagulation as well. In subsequent follow-up, it was noted significant improvements in terms of her symptoms. Conclusion Vaso-occlusive retinopathy is a rare, potentially vision-threatening initial manifestation of SLE, which can be an indicator of active disease. Early identification of patients is necessary for timely intervention and multidisciplinary team involvement is required for comprehensive treatment plans. Disclosure M. Islam: None. S. Quddus: None. M. Hughes: None. R. Kumar: None.

Bloodstream Infection caused by Corynebacterium striatum in COVID-19 patient

Objectives: Recent research recognized coryneform bacteria as emerging opportunistic pathogens. Corynebacterium striatum appears as a significant pathogen in immunocompromised and immunocompetent patients. Methods: In this paper, we report a case of an adult COVID-19 patient with C. striatum bloodstream infection. In addition, we reviewed clinical cases of bloodstream infection caused by Corynebacterium spp, mainly C. striatum. Results: We present a 43-year-old patient hospitalized due to bilateral pneumonia caused by a SARS-CoV-2 infection. During hospitalization, the patient was connected to a veno-venous extracorporeal membrane oxygenation (ECMO) circuit. C. striatum was isolated in seven sets of blood cultures sampled over seven consecutive days. Based on identification done by MALDI- ToF, empirical therapy with vancomycin was initiated. Identification was confirmed by 16S ribosomal RNA gene sequencing. Although central venous catheter was replaced, C. striatum was persistently isolated in blood cultures in the following days. Although replacement of the ECMO cannula would be recommended, the procedure was not performed due to the severe patient's condition. Fosfomycin was added to vancomycin as salvage therapy in order to reorganize the structure of the biofilm and enable better penetration and efficacy of vancomycin which resulted in sterile blood cultures in the following days. Conclusion: During the last decades, there have been many examples of bloodstream infections caused by skin contaminants. Although the central venous catheter is most commonly described as a route of entry of the skin microbiota in the bloodstream, other catheters such as pleural catheter and ECMO system, should not be neglected. It is well known that bacterial cells often form a biofilm on the surface of different medical devices such as central venous catheters, endoscopes, and urinary catheters. Fosfomycin has the potential to penetrate the biofilm, transform the biofilm structure and potentially increase the concentration of other antimicrobial agents in the biofilm.

Association of persistent positive blood cultures and infective endocarditis: A cohort study among patients with suspected infective endocarditis

ObjectivesTo ascertain whether infective endocarditis (IE) was associated with persistent bacteraemia/candidaemia among patients with suspected IE. MethodsThis study included bacteraemic/candidaemic adult patients with echocardiography and follow-up blood cultures. Persistent bacteraemia/candidaemia was defined as continued positive blood cultures with the same microorganism for 48 h or more after antibiotic treatment initiation. Each case was classified for IE by the Endocarditis Team. ResultsAmong 1962 episodes of suspected IE, IE (605; 31%) was the most prevalent infection type. Persistent bacteraemia/candidaemia was observed in 426 (22%) episodes. Persistent bacteraemia was more common among episodes with Staphylococcus aureus bacteraemia compared to episodes with positive blood cultures for other pathogens (32%, 298/933 vs 12%, 128/1029; P < 0.001). Multivariable analysis demonstrated that cardiac predisposing factors (aOR 1.84, 95% CI 1.31-2.60), community or non-nosocomial healthcare-associated (2.85, 2.10-3.88), bacteraemia by high-risk bacteria, such as S. aureus, streptococci, enterococci or HACEK (1.84, 1.31-2.60), two or more positive sets of index blood cultures (6.99, 4.60-10.63), persistent bacteraemia/candidaemia for 48 h from antimicrobial treatment initiation (1.43, 1.05-1.93), embolic events within 48h from antimicrobial treatment initiation (12.81, 9.43-17.41), and immunological phenomena (3.87, 1.09-1.78) were associated with infective endocarditis. ConclusionsIE was associated with persistent bacteraemia/candidaemia, along with other commonly associated factors.

Diagnostic Yield of Blood Cultures among Patients Admitted with Non-Focal Pyrexias

OBJECTIVES To establish the diagnostic yield of blood cultures among patients admitted with non-focal pyrexias. METHODOLOGY This descriptive cross-sectional study was conducted in the Department of Medicine, Khyber Teaching Hospital, Peshawar, from August 2020 to April 2021. One hundred ninety-seven patients with non-focal pyrexia were recruited. Data about age, gender, presence of other illnesses like diabetes and hypertension, history of smoking and duration of fever were noted. A thorough clinical evaluation was done. Under aseptic conditions, 2 blood culture sets were taken. The final blood culture report was collected after 5 days of incubation in culture media. The culture was labelled positive if any organism was isolated from the sample. All data was entered in specially designed proforma. Patients with positive blood cultures were managed as per hospital protocols. Confidentiality of data was ensured. RESULTSOur study shows that among 197 patients, 18(9%) had positive cultures, while 179(91%) did not yield any pathogen on blood culture. Escherichia coli was the most commonly grown organism among the positive blood cultures. CONCLUSION The yield of blood culture was 9% in febrile patients admitted to the medical ward of a tertiary care hospital.

Impact of Blood Culture Contamination on Antibiotic Use, Resource Utilization, and Clinical Outcomes: A Retrospective Cohort Study in Dutch and US Hospitals.

Blood culture contamination (BCC) has been associated with prolonged antibiotic use (AU) and increased health care utilization; however, this has not been widely reevaluated in the era of increased attention to antibiotic stewardship. We evaluated the impact of BCC on AU, resource utilization, and length of stay in Dutch and US patients. This retrospective observational study examined adults admitted to 2 hospitals in the Netherlands and 5 hospitals in the United States undergoing ≥2 blood culture (BC) sets. Exclusion criteria included neutropenia, no hospital admission, or death within 48 hours of hospitalization. The impact of BCC on clinical outcomes-overall inpatient days of antibiotic therapy, test utilization, length of stay, and mortality-was determined via a multivariable regression model. An overall 22 927 patient admissions were evaluated: 650 (4.1%) and 339 (4.8%) with BCC and 11 437 (71.8%) and 4648 (66.3%) with negative BC results from the Netherlands and the United States, respectively. Dutch and US patients with BCC had a mean ± SE 1.74 ± 0.27 (P < .001) and 1.58 ± 0.45 (P < .001) more days of antibiotic therapy than patients with negative BC results. They also had 0.6 ± 0.1 (P < .001) more BCs drawn. Dutch but not US patients with BCC had longer hospital stays (3.36 days; P < .001). There was no difference in mortality between groups in either cohort. AU remained higher in US but not Dutch patients with BCC in a subanalysis limited to BC obtained within the first 24 hours of admission. BCC remains associated with higher inpatient AU and health care utilization as compared with patients with negative BC results, although the impact on these outcomes differs by country.

Performance evaluation of 4-day versus 5-day blood cultures using the BD BACTEC FX system

Background: Blood culture (BC) systems have evolved to increase sensitivity and reduce turnaround times. This study compared the performance of a 4-day versus a 5-day BC incubation period using the BD BACTEC™ FX (Becton, Dickinson and Company, USA). Methods: A total of 37,379 consecutive sets of BC were evaluated over a 3-month period in a 2,700-bed tertiary care hospital. Positive BC results were reviewed to assess time-to-positivity (TTP) and species identification of the isolates. The BCs were performed in pairs of vials, utilizing either BD BACTEC Plus Aerobic/F or Peds Plus/F with BD BACTEC Lytic Anaerobic media. Results: A total of 14,899 episodes, averaging 2.51 sets per episode, were analyzed. Of these, 1,398 (9.38%) were positive, yielding 1,465 isolates. TTP (hours) were &lt; 12 in 48.87%, 12-24 in 31.40%, 24-48 in 13.38%, 48-72 in 3.28%, 72-96 in 1.43%, and &gt;96 in 1.64%. The two most prevalent organisms, Escherichia coli and Klebsiella spp. were detected within 12 hours in 88.75% and 78.90%, respectively. The respective median TTP (T50) values for E. coli, Klebsiella spp., Enterococcus faecalis/E. faecium, and Staphylococcus aureus were 9.24, 9.60, 13.75, and 14.20. T50 values for these species were significantly shorter in anaerobic bottles than in aerobic bottles. Of 24 BCs with TTP &gt; 96, only 4 containing anaerobic bacteria or molds were f irst detected after 96 hours. Conclusion: A 4-day incubation has demonstrated excellent sensitivity. However, a 5-day incubation may be beneficial for hospitals caring for patients at high risk for infections with slow-growing fungi or fastidious bacteria.

Luteibacter jiangsuensis blood stream infection: a first case report

BackgroundLuteibacter jiangsuensis is a gram-negative aerobic bacillus that was first isolated from soil samples at a pesticide factory in China and reported in 2011. Here, we describe the first case of L. jiangsuensis infection in human.Case presentationA 59-year-old Japanese woman undergoing treatment for Crohn’s disease was admitted to our hospital with fever. Clinical examination indicated catheter-related bloodstream infection. The catheter was removed and meropenem was initiated. Morphologically identical glucose non-fermentative gram-negative bacilli were detected from two sets of aerobic blood culture and catheter-tip cultures. MALDI-TOF mass spectrometry failed to identify the bacterium, which was later identified as L. jiangsuensis by 16 S rRNA gene sequencing. Antimicrobial susceptibility test revealed that the isolate was resistant to carbapenem, therefore meropenem was switched to intravenous levofloxacin (500 mg/day). After 14 days of treatment with levofloxacin, the patient was discharged.ConclusionsThis is the first case of L. jiangsuensis infection in human. The strain was identified by 16 S rRNA gene sequence analysis.

Laboratory approaches to determining blood culture contamination rates: an ASM Laboratory Practices Subcommittee report.

Blood culture contamination (BCC) is the presence of specific commensal and environmental organisms cultivated from a single blood culture set out of a blood culture series and that do not represent true bacteremia. BCC can impact quality of care and lead to negative outcomes, unnecessary antibiotic exposure, prolonged hospital stays, and substantial costs. As part of the laboratory's quality management plan, microbiology laboratory personnel are tasked with monitoring BCC rates, preparing BCC rate reports, and providing feedback to the appropriate committees within their healthcare system. The BCC rate is calculated by the laboratory using pre-set criteria. However, pre-set criteria are not universally defined and depend on the individual institution's patient population and practices. This mini-review provides practical recommendations on elaborating BCC rate reports, the parameters to define for the pre-set criteria, how to collect and interpret the data, and additional analysis to include in a BCC report.

Yield of Repeat Blood Cultures in Acute Myeloid Leukemia Patients Following Allogeneic Hematopoietic Stem Cell Transplantation

Introduction: Unnecessary repeat blood culture collection has been demonstrated to increase health care costs, length of stay, duration of antimicrobial exposure, and risk of anemia and result in unnecessary removal of vascular catheters. The aim of this study was to characterize the yield of new pathogen identification in acute myeloid leukemia (AML) patients with known bacteremia in the post-allogeneic hematopoietic stem cell transplant (HSCT) period. Methods: This was a retrospective study of AML patients who underwent allogeneic HSCT at Taussig Cancer Center from January 1 st 2019 to December 31 st 2022. Patients who experienced an occurrence of febrile neutropenia (FN) within 35 days of date of HSCT and had positive initial blood cultures within 24 hours of diagnosis of FN were included in the study. Patients who had at least 1 additional set of repeat cultures drawn following initial blood cultures were included in the study. Blood cultures were collected through a peripheral site via venipuncture or through a central line. The study was approved by the Institutional Review Board. Data were collected on baseline patient characteristics, AML disease characteristics, HSCT characteristics, and infection characteristics. Febrile neutropenia was defined as recorded temperature ≥ 100.4°F with concurrent ANC &amp;lt;1500 cells/uL. Each patient day with a recorded temperature ≥100.4°F and ANC &amp;lt;1500 cells/μL was considered as a day of FN. An episode of FN was considered to be resolved following 72 hours of defervescence. Cultures drawn within 24 hours of onset of FN were considered the initial blood cultures. All subsequent sets of blood cultures were considered repeat blood cultures. A positive set of blood culture was defined as &amp;gt;50% of all blood cultures in that set growing an organism. Cultures drawn from all peripheral and central sites on the same day of FN were considered as one set of blood cultures. All patients received post-HSCT anti-bacterial prophylaxis with bactrim or ciprofloxacin. Results: A total of 154 AML patients who underwent HSCT at Taussig Cancer Center were screened for the study. 50/154 (32.5%) of those patients met inclusion criteria and were included in the study. Among the 50 patients included in the study, there were 50 episodes of FN with positive initial blood cultures that were diagnosed within 35 days of HSCT. There were 120 total days of FN among the 50 episodes of FN with an average of 2.4 days per episode. 50 initial sets of blood cultures and 96 sets of repeat blood cultures were drawn between the 50 episodes of FN with an average of 2.9 total sets of blood cultures per episode. 12/96 (12.5%) of repeat blood cultures sets were positive for a pathogen. 3/96 (3.1%) of repeat blood cultures sets grew a pathogen that differed from the pathogen which grew in the preceding positive blood culture. The median duration of febrile neutropenia at time of repeat positive culture was 3.5 days. 30-day mortality rate from infection was 6.0% (3/50). Conclusion: Even amongst bacteremic AML patients in the post-HSCT period, the yield of repeat blood cultures was low for detecting new pathogen identification. Repeat blood cultures should be guided by thorough evaluation of emerging clinical signs and symptoms.

Impact of Concurrent and Previous Multidrug Resistant Bacteria Colonization in Adult Allogenic Hematopoietic Stem Cell Transplant Patients with Acute Leukemia: A Single Center Retrospective Study

Background Multidrug resistant bacteria (MDRB) pose a major challenge in allogenic hematopoietic stem cell transplant (allo-HSCT) since patient colonization with Gram - or Gram + MDRB has been identified as a risk factor for infections, acute graft versus host disease (aGVHD) and reduced overall survival (OS). Nevertheless, data on the prognostic value of MDRB colonization are still scarce, and whether it should represent a limit to allo-HSCT eligibility is controversial. Few data are also available on the impact of previously detected colonization that are absent at transplant time. Methods This is a retrospective single center study on 60 patients with acute myeloid or lymphoblastic leukemia who underwent allo-HSCT from January 2014 to March 2023 according to JACIE standards.All patients were treated at our department starting from induction. In each hospital stay MDRB colonization was assessed by rectal swabs performed at admission, and thereafter weekly. In case of fever 3 sets of blood culture from peripheral vein and central venous catheters, urine culture and chest X-ray were performed, and empiric antibiotic therapy initiated. In MDRB colonized patients, targeted antibiotic therapy was administered if clinically indicated. All patients received fluroquinolones as antimicrobial prophylaxis. Data were retrieved from hospital records. Aim of the study To assess the epidemiology of MDRB colonization and the related impact on allo-HSCT outcome in terms of MDRB-related infections, aGVHD within day 100, OS and non-relapse mortality (NRM). Results MDRB colonization was detected in 26/60 (43.4%) patients, in 13 (21.7%) at hospital admission and in additional 13 (21.7%) after allo-HSCT. Overall, 33 MDRB strains were isolated (Table 1). Among patients colonized at hospital admission, Gram - MDRB accounted for 10/16 (62.5%) strains, mostly Escherichia Coli producing extended-spectrum beta-lactamases (ESBL) and Klebsiella Pneumoniae ESBL, while Gram + MDRB were 6 (37.5%), mostly represented by vancomycin-resistant Enterococcus faecium (VRE). In 14/16 (87.5%) cases the colonization has been previously detected, in 78.5% since the first two hospital stays. Among patients with positive rectal swabs after allo-HSCT, Gram - MDRB accounted for 16/17 (94.1%) strains, mostly Escherichia Coli ESBL and Klebsiella Pneumoniae ESBL (1 producing carbapenemases). In these patients the rectal swab turned out positive after a median time of 10 (2-24) days after allo-HSCT, mostly during neutropenia. Albeit absent at hospital admission, 13/17 (76.5%) MDRB strains had been previously isolated in the same patients, being firstly identified during the first two hospital stays in 76.9% cases. No significant differences in patient baseline characteristics, leukemia classification, type of donor and conditioning or hospitalization length were observed between MDRB carriers (26, 43.4%) and non-carriers (34, 56.8%) (Table 2). During the whole hospital stay, 18/26 (69%) carriers and 32/34 (94%) non-carriers reported at least one febrile event (p=0.01). Only carriers experienced MDRB (Gram -) infections based on blood (4, 22%) and urine (7, 38%) culture, while the rate of positive chest X-ray (4, 22,2% vs 5, 15.6%, p=0.5) did not differ. Targeted antibiotics were administered to 14/18 (77.8%) febrile carriers, in 10 (71%) at fever onset and in 4 (29%) at fever persistence. Four (22.2%) did not receive treatment because not clinically indicated. Intensive care unit was never required in both cohorts. The incidence of aGVHD was similar between carriers and non-carriers (10, 38.5% vs 17, 50%, p=ns), but the proportion of grade 2-4 tended to be higher in the first group (70% vs 35.5%, p=0.08). Overall, 73% patients are alive with a median follow-up of 18 (0.8-49) months. Median OS was not reached in both groups (p=0.09). There was no difference in NRM between carriers and non-carriers (5, 19% vs 2, 6%, p=0.11). Conclusion In our series 43.3% of allo-HSCT patients were colonized by MDRB that, in line with recent literature, were mostly Gram -. The absence of life-threatening infections and the non-significantly inferior OS and NRM in colonized patients suggest that a careful investigation of concurrent and previous colonization and a prompt use of targeted antibiotics may temper the negative impact of MDRB-related infections in adult acute leukemia patients undergoing allo-HSCT. Larger prospective studies are awaited.

235. Investigation of the relationship between the number of positive blood cultures and patient prognosis

Abstract Background The relationship between the number of positive blood cultures (NPBCs) and clinical outcomes has not been well-studied. The purpose of this study was to assess the impact of NPBCs (one set or two) on clinical outcomes. Methods We conducted a retrospective study comparing the clinical features of two sets of positive blood cultures (NPBCs=2) and one set of positive blood culture (NPBCs=1) in adult patients with bacteremia and fungemia from 2004 to 2021 at a tertiary hospital in Tokyo, Japan. We focused on four pathogens commonly encountered in clinical practice, including Staphylococcus aureus (S. aureus), Streptococci, gram-negative rods (GNR) (Enterobacterales and Pseudomonas aeruginosa), and Candida species, as the true causative pathogens in bacteremia and fungemia. The primary outcome was in-hospital mortality, and secondary outcomes were ICU admission and use of vasopressor drugs. Results In univariate analysis, NPBCs=2 for S. aureus was associated with vasopressor use, and NPBCs=2 for Streptococci was linked to a higher rate of ICU admission. However, these differences were not significant in multivariate analysis. Interestingly, NPBCs=2 for S. aureus had a positive impact on in-hospital mortality compared with NPBCs=1 (OR 0.574, 95%CI 0.376–0.877, p &amp;lt; 0.05). NPBCs for Candida species did not affect clinical outcomes. Furthermore, NPBCs=2 for GNR was associated with vasopressor use (OR 1.62, 95%CI 1.27–2.07, p &amp;lt; 0.05) in both univariate and multivariate analysis. We performed logistic regression analysis using the five items with the highest clinical significance: NPBCs=2, serum Cr &amp;gt; 1.2 mg/dL, Hb &amp;lt; 12 g/dL, heart rate &amp;gt; 90 beats/min, and platelet count &amp;lt; 150,000/μL. Based on the β coefficient, we assigned scores to each item and created a STAT-2 (S: Serum Cr, T: Thrombocytopenia, A: Anemia, T: Tachycardia, 2: NPBCs=2) score for the use of hypertensive drugs for GNR. The receiver operating characteristic (ROC) curve for the STAT-2 score with a cutoff of 6 points or higher had an area under the curve (AUC) of 0.763. The specificity was 90.8%, with a positive likelihood ratio of 4.13 (95% CI 3.40-5.02). Conclusion Our study suggests that NPBCs can predict clinical outcomes in patients with certain pathogenic infections. Disclosures All Authors: No reported disclosures