298. Multicenter retrospective cohort study of the clinical significance of Staphylococcus lugdunensis isolated from a single blood culture set

Abstract Background Staphylococcus lugdunensis is a coagulase negative Staphylococcus (CoNS) species with the potential to cause aggressive infection. Guidance surrounding S. lugdunensis bacteremia (SLB) is lacking, especially in the case of a single positive set of blood cultures. Methods We performed a multicenter, retrospective observational cohort review of adult patients with SLB from at least one blood culture set within the University of Maryland Medical System from November 2015-November 2019. Objectives were to (1) describe baseline characteristics, (2) compare available criteria for evaluating clinical significance, and (3) evaluate the clinical outcomes among patients with SLB in 1 vs ≥2 positive blood culture sets. Descriptive statistics with Chi-squared and Mann-Whitney U tests were carried out. Results There were 5,548 CoNS-positive blood culture sets, 49 (0.88%) with S. lugdunensis comprising 36 adult patients (24 with 1 positive set and 12 with ≥2 positive sets). Patients with ≥2 positive sets were more likely to be on hemodialysis (HD) (p=0.029) and to have an HD catheter present (p=0.10) (Table 1). Thirty-five of the 36 patients fulfilled at least one of the following: systemic inflammatory response syndrome (SIRS), Souvenir criteria, or clinical criteria (infectious focus on imaging and/or second positive culture site) (Table 2). Twenty-eight (78%) patients were treated with antimicrobial therapy and/or central line removal. SIRS criteria were met more often among patients with 1 positive set (p=0.05). Patients with ≥2 positive sets were more often treated with antibiotics for longer than 2 weeks (p=0.02). The mean time of positive cultures to discharge was 11 days and was longer for patients with only one set of positive blood cultures (13 vs. 6 days), although this difference was not statistically significant (p=0.29) (Table 3). Conclusion SLB was rare and occurred more frequently as a single set of positive blood cultures. Though limited by sample size, this study found similar patient characteristics, clinical significance and outcomes between patients with one set and those with ≥2 sets of blood cultures positive for S. lugdunensis. Given the potential severity of SLB, it seems prudent to treat S. lugdunensis in a single blood culture, but larger studies are needed. Disclosures All Authors: No reported disclosures

Download Full-text

182. Clinical Presentation of Patients with Staphylococcus lugdunensis Positive Blood Cultures After the Implementation of Rapid Molecular Blood Culture Diagnostics

Open Forum Infectious Diseases ◽

10.1093/ofid/ofab466.384 ◽

2021 ◽

Vol 8 (Supplement_1) ◽

pp. S199-S200

Author(s):

Kristin Constance ◽

Alauna Hunt ◽

Sam Karimaghaei ◽

Nigo Masayuki

Keyword(s):

Blood Culture ◽

Bloodstream Infection ◽

Positive Blood Culture ◽

Central Line ◽

Blood Cultures ◽

Coagulase Negative Staphylococcus ◽

Medical Systems ◽

Hospital System ◽

Severe Infections ◽

Acid Test

Abstract Background Since the implementation of improved laboratory techniques, coagulase negative Staphylococcus (CoNS) have been routinely speciated to screen for S. lugdunensis (SL), which has led to increased identification. The objective of this study is to describe the characteristics of patients with SL positive blood cultures after the introduction of Verigene® Gram-Positive Blood Culture Nucleic Acid Test (BC-GP) in two large medical systems. Methods Retrospective review of all blood culture isolates positive for SL from Memorial Hermann Hospital System (14 hospitals) and HarrisHealth System (two acute care hospitals) since implementation of BC-GP. Results Between 2017 – 2021, 157 patients had SL positive blood cultures. 18 were eliminated as cultures were positive for bacteria other than CoNS, and 7 eliminated as patients were discharged prior to culture results. Of the remaining 132 patients, 39 (29.5%) were labelled contaminants by the treating physician and 93 were considered true bacteremia. Patients with hardware/implanted materials were more likely considered to have true bacteremia, while patients with other CoNS species in blood cultures were more likely considered contaminants. Only one death was attributed to SL bloodstream infection in the true bacteremia group. None of the deaths in the contaminated group were attributed to SL infection. Of the 93 patients labelled true bacteremia, the source was most frequently listed as central line associated bloodstream infection (17.2%), followed by skin/soft tissue infection (11.8%), and infective endocarditis (IE) (10.8%). Table 1. Characteristics of Patients with S. lugdunensis Positive Blood Cultures Conclusion In our study, 29% of patients with positive blood culture for SL were deemed contaminants. Patients without hardwares or positive concomitant other CoNS species from the same blood culture were often considered as contaminated cases. The incidence of IE remains as high as 10.8% in those patients identified to have true bacteremia (7.6% overall in our cohort), although lower than previously reported cases. Careful evaluation is warranted in patients with positive SL blood culture to rule out severe infections and avoid unnecessary courses of antibiotic therapy. This study suggests that increased identification of SL may impact our understanding of its significance and pathogenicity over time. Disclosures All Authors: No reported disclosures

Download Full-text

81. Reducing Unnecessary Blood Cultures Through Diagnostic Stewardship

Open Forum Infectious Diseases ◽

10.1093/ofid/ofab466.283 ◽

2021 ◽

Vol 8 (Supplement_1) ◽

pp. S157-S157

Author(s):

Sujeet Govindan ◽

Luke Strnad

Keyword(s):

Blood Culture ◽

Positive Blood Culture ◽

Cost Savings ◽

Bloodstream Infections ◽

Central Line ◽

Blood Cultures ◽

Coagulase Negative Staphylococci ◽

Candida Sp ◽

Daily Frequency ◽

Oregon Health

Abstract Background At our institution, we learned the frequency of blood cultures was sometimes being changed from “Once” to “Daily” without a defined number of days. We hypothesized this led to unnecessary blood cultures being performed. Methods Over a 3 month period from 12/6/2019-3/6/2020, we retrospectively evaluated the charts of patients who had a blood culture frequency changed to “Daily”. We evaluated if there was an initial positive blood culture within 48 hours of the “Daily” order being placed and the number of positive, negative, or “contaminant” sets of cultures drawn with the order. Contaminant blood cultures were defined as a contaminant species, present only once in the repeat cultures, and not present in initial positive cultures. Results 95 unique orders were placed with 406 sets of cultures drawn from 89 adults. ~20% of the time (17 orders) the order was placed without an initial positive blood culture. This led to 62 sets of cultures being drawn, only 1 of which came back positive. 78/95 orders had an initial positive blood culture. The most common initial organisms were Staphylococcus aureus (SA) (38), Candida sp (10), Enterobacterales sp (10), and coagulase negative staphylococci (7). 43/78 (55%) orders with an initial positive set had positive repeat cultures. SA (26) and Candida sp (8) were most common to have positive repeats. Central line associated bloodstream infections (CLABSI) were found in 5 of the orders and contaminant species were found in 4 of the orders. 54% of the patients who had a “Daily” order placed did not have positive repeat cultures. The majority of the cultures were drawn from Surgical (40 orders) and Medical (35 orders) services. Assuming that SA and Candida sp require 48 hours of negative blood cultures to document clearance and other species require 24 hours, it was estimated that 51% of the cultures drawn using the "Daily" frequency were unnecessary. Cost savings over a year of removing the "Daily" frequency would be ~&14,000. Data from "Daily" blood culture orders drawn at Oregon Health & Science University from 12/6/2019-3/6/2020 Conclusion Unnecessary blood cultures are drawn when the frequency of blood cultures is changed to "Daily". Repeat blood cultures had the greatest utility in bloodstream infections due to SA or Candida sp, and with CLABSI where the line is still in place. These results led to a stewardship intervention to change blood culture ordering at our institution. Disclosures All Authors: No reported disclosures

Download Full-text

2178. Sensitivity of Blood Cultures in Detection of Bacteremia in Febrile Neutropenia

Open Forum Infectious Diseases ◽

10.1093/ofid/ofz360.1858 ◽

2019 ◽

Vol 6 (Supplement_2) ◽

pp. S739-S739

Author(s):

Vanisha Patel ◽

Jose Amadeo A Ferrolino ◽

Randall Hayden ◽

Aditya H Gaur

Keyword(s):

Blood Culture ◽

Febrile Neutropenia ◽

Positive Blood Culture ◽

Culture Media ◽

Febrile Episode ◽

Advisory Board ◽

Blood Cultures ◽

Coagulase Negative Staphylococcus ◽

Media Type ◽

Time To Detection

Abstract Background Febrile neutropenia (FN) secondary to bacteremia is a treatable complication of chemotherapy that increases mortality if not promptly recognized and managed. Methods The sensitivity of blood cultures collected in pediatric oncology patients with FN was assessed and stratified based on the day of FN episode, culture media type, and the source of blood culture draw at a single US center between 2013 and 2018. Paired aerobic and lytic media bottles were inoculated with each culture draw using a weight-based volume of blood; anaerobic cultures were included with initial cultures starting in September of 2015. Results In a retrospective analysis of 10,596 patients, a total of 3,039 episodes of FN were identified. Of the FN episodes, 17.7% had at least one positive blood culture; 84.5%, 1.3%, 0.9% and 13.3% of positive cultures were collected on day 0, day 1, day 2 and ≥ day 3 of a febrile episode. Among the positive day 0 cultures, the median time to detection of an organism was 14.1 hours. Host characteristics of blood culture-positive FN episodes are summarized in Table 1. Bacteremia was identified in 537 FN cases; 18.1%, 11.9% and 2.6% of cultures were positive in only aerobic, lytic or anaerobic media cultures, respectively. The most commonly isolated organisms were Escherichia coli, coagulase-negative Staphylococcus, viridans group streptococcus, Klebsiella pneumoniae and Pseudomonas aeruginosa. Fifteen percent of infectious episodes with a positive blood culture were polymicrobial. Conclusion In summary, the study findings have important clinical implications such as emphasizing the value of day 0 cultures and highlighting the importance of routinely collecting blood cultures in more than one media type. Despite an optimized blood culture approach, less than a fifth of FN episodes had a blood culture-based diagnosis. Disclosures Randall Hayden, MD, Abbott Molecular: Advisory Board; Quidel: Advisory Board; Roche Diagnostics: Advisory Board.

Download Full-text

Nosocomial Bacteremia Clinical Significance of a Single Blood Culture Positive for Coagulase-Negative Staphylococci

Infection Control and Hospital Epidemiology ◽

10.1086/502605 ◽

2005 ◽

Vol 26 (8) ◽

pp. 697-702 ◽

Cited By ~ 39

Author(s):

Benoît Favre ◽

Stéphane Hugonnet ◽

Luci Correa ◽

Hugo Sax ◽

Peter Rohner ◽

...

Keyword(s):

Blood Culture ◽

Clinical Significance ◽

Positive Blood Culture ◽

Blood Cultures ◽

University Teaching ◽

Coagulase Negative Staphylococci ◽

Nosocomial Bacteremia ◽

Single Positive ◽

Clinically Significant ◽

Culture Positive

AbstractObjectives:To describe the epidemiology of nosocomial coagulase-negative staphylococci (CoNS) bacteremia and to evaluate the clinical significance of a single blood culture positive for CoNS.Design:A 3-year retrospective cohort study based on data prospectively collected through hospital-wide surveillance. Bacteremia was defined according to CDC criteria, except that a single blood culture growing CoNS was not systematically considered as a contaminant. All clinically significant blood cultures positive for CoNS nosocomial bacteremia were considered for analysis.Setting:A large university teaching hospital in Geneva, Switzerland.Results:A total of 2,660 positive blood cultures were identified. Of these, 1,108 (41.7%) were nosocomial; CoNS were recovered from 411 nosocomial episodes (37.1%). Two hundred thirty-four episodes of CoNS bacteremia in the presence of signs of sepsis were considered clinically relevant and analyzed. Crude mortality and associated mortality were 24.4% and 12.8%, respectively. Associated mortality was similar among patients with one positive blood culture and those with two or more (16.2% vs 10.8%, respectively;P= .3). Mortality rates after bacteremia for patients with a single positive blood culture and for those with two or more were 15.3% and 7.0%, respectively, at day 14 (RR, 2.2; CI%, 0.87-5.46) and 20.8% and 11.3%, respectively, at day 28 (RR, 1.9; CI95, 0.9-3.8). On multivariate analysis, only age and a rapidly fatal disease were independently associated with death.Conclusion:CoNS bacteremia harbor a significant mortality and a single positive blood culture in the presence of signs of sepsis should be considered as clinically relevant.

Download Full-text

160. Could Reducing Time to Bacterial Identification From Positive Blood Cultures Improve Outcomes in Bacteremic Patients?

Open Forum Infectious Diseases ◽

10.1093/ofid/ofz360.235 ◽

2019 ◽

Vol 6 (Supplement_2) ◽

pp. S105-S105

Author(s):

Jessica D Forbes ◽

Reem Haj ◽

Linda R Taggart ◽

Ramzi Fattouh ◽

Elizabeth Leung ◽

...

Keyword(s):

Blood Culture ◽

Positive Blood Culture ◽

Patient Management ◽

Diagnostic Testing ◽

Empiric Therapy ◽

Central Line ◽

Blood Cultures ◽

Antibiotic Administration ◽

Organism Identification ◽

The Impact

Abstract Background Survival of patients with septic shock is dependent on the timing of effective antibiotic administration. The initial notification by the microbiology lab of a positive blood culture is a key factor in improving patient outcomes. It can take >24 hours to definitively identify bacteria from positive blood cultures. Accordingly, we employed rapid organism identification and studied the impact of this on patient management from a quality improvement perspective. Methods Rapid organism identification was performed for bacteremic patients admitted to an ICU at St. Michael’s Hospital in Toronto, ON, by creating a pellet from positive blood culture bottles using a lysis centrifugation technique. MALDI-TOF was then used to obtain an organism identification. The microbiology lab verbally notified the ward clerk of the identification and surveys were conducted with treating physicians within 24–48 hours to evaluate the downstream impact of the rapid identification including changes to antibiotics, diagnostic testing, central line management and requests for specialty consultations. Results Between January 28 and April 28, 2019, 17 rapid blood culture results were included for study. When asked how physicians received the result, in 7 cases the physician did not remember; other responses included microbiology report (2), nurse (2), pharmacist (1), antimicrobial stewardship or lab (1), on-call team (1) and residents (1). Antibiotics were adjusted in 13 patients; 3 of which may have changed antibiotics for reasons other than the organism identification. Reasons for not changing therapy include: appropriate empiric treatment, likely contaminants, or physician not being notified of the result. In 5 cases, all antibiotics were discontinued, in another 2 cases the antibiotics were broadened and a further 5 narrowed to cover the organism; the remaining 5 continued the same empiric therapy. Repeat blood cultures were obtained for 5 cases, follow-up imaging in 5 cases and lines were changed/removed in 5 cases. Consultation was requested for 7 cases. Conclusion Based on preliminary data, rapid organism identification shows promise of improved patient management with line removal and antibiotics adjustments occurring 1 day sooner with rapid results. Disclosures All authors: No reported disclosures.

Download Full-text

Application of an Outpatient CLABSI Surveillance Definition: Results and Lessons From 7 Infusion Clinics

Infection Control and Hospital Epidemiology ◽

10.1017/ice.2020.634 ◽

2020 ◽

Vol 41 (S1) ◽

pp. s124-s124

Author(s):

Keenan Williamson ◽

Chad Douglas Nix ◽

Molly Hale

Keyword(s):

Blood Culture ◽

Positive Blood Culture ◽

Symptom Onset ◽

Central Line ◽

Clinic Visit ◽

Case Definition ◽

Blood Cultures ◽

Ambulatory Setting ◽

Inpatient Setting ◽

Site Specific

Background: The NHSN does not have a published surveillance definition for central-line–associated bloodstream infections (CLABSIs) related to healthcare in ambulatory settings. With the increasing reliance on services involving central-line care in the ambulatory setting, there is opportunity to improve healthcare performance by developing standardized surveillance. Methods: Chart review was performed on 320 patients who had a visit at an infusion clinic and a positive blood culture in 2018. A qualifying infusion clinic visit involved accessing of the central line during the encounter. Ambulatory-associated cases were defined as having a qualifying infusion clinic encounter within 7 days prior to blood culture collection. Cases were excluded if the patient’s central line had been accessed in an inpatient setting between the positive blood culture and infusion clinic visit. All other criteria were based on the NHSN inpatient CLABSI case definition. Results: Application of the proposed surveillance definition revealed 17 of 320 (5.3%) patients who met criteria for an ambulatory CLABSI. All 16 patients who met criteria (94%) had an inpatient hospital stay within 7 days of the qualifying infusion clinic encounter, for an average of 8.8 hospital days (range, 2–20). Positive blood cultures were collected on average 3.2 days after the patient’s qualifying infusion clinic encounter (range, 0–7). Moreover, 20 causative organisms were identified: 6 common commensals, 2 Staphylococcus aureus, and 12 gram-negative bacteria. Also, positive blood cultures for 7 patients (41%) were collected in ambulatory clinics. Patients reported symptom onset on average 1.2 days prior to telling a healthcare professional (range, 0–5) and an average of 2 days from their last qualifying infusion clinic visit (range, 0–6). In addition, 1 patient (6%) met for a site-specific infection outside of the defined window period during their subsequent admission. Conclusions: Application of the surveillance definition resulted in the identification of 17 CLABSIs. These results highlight important limitations in ambulatory CLABSI surveillance: Patients who access emergency services closer to their residence may have had their bloodstream infection (BSI) identified elsewhere. Ensuring comprehensive interfacility communication would increase the value of an institution’s surveillance. Additionally, ambulatory surveillance for BSI should include all possible collection locations. Although subject to recall bias, the event date could be based on symptom onset to allow for variation in healthcare-seeking behavior. In the ambulatory setting, because diagnostics are not readily available, delayed diagnosis of site-specific infections could result in an inflated ambulatory CLABSI rate.Funding: NoneDisclosures: None

Download Full-text

Clinical Significance of a Single Staphylococcus lugdunensis-Positive Blood Culture

Journal of Clinical Microbiology ◽

10.1128/jcm.02058-10 ◽

2011 ◽

Vol 49 (4) ◽

pp. 1697-1699 ◽

Cited By ~ 23

Author(s):

H. J. Fadel ◽

R. Patel ◽

E. A. Vetter ◽

L. M. Baddour

Keyword(s):

Blood Culture ◽

Clinical Significance ◽

Positive Blood Culture ◽

Staphylococcus Lugdunensis

Download Full-text

Comparison of Pharmacist-Directed Management of Multiplex PCR Blood Culture Results with Conventional Microbiology Methods on Effective and Optimal Therapy within a Community Hospital

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01575-18 ◽

2018 ◽

Vol 63 (1) ◽

Cited By ~ 3

Author(s):

Allison M. Porter ◽

Christopher M. Bland ◽

Henry N. Young ◽

David R. Allen ◽

Sabrina R. Croft ◽

...

Keyword(s):

Blood Culture ◽

Multiplex Pcr ◽

Positive Blood Culture ◽

Antimicrobial Therapy ◽

Community Hospital ◽

Intervention Group ◽

Standard Of Care ◽

Pharmacist Intervention ◽

Coagulase Negative Staphylococcus ◽

Optimal Therapy

ABSTRACT Multiplex PCR combined with a pharmacist-driven reporting protocol was compared to the standard of care within a community hospital to evaluate initial changes after notification of a positive blood culture. The intervention group demonstrated decreased times to changes in antimicrobial therapy (P = 0.0081), increased changes to optimal antimicrobial therapy (P = 0.013), and decreased vancomycin use for coagulase-negative staphylococcus contaminants (P < 0.01) with multiplex PCR implementation and pharmacist intervention.

Download Full-text

Clinical significance of follow-up blood culture in patients with a single Staphylococcus aureus-positive blood culture

Infectious Diseases ◽

10.1080/23744235.2019.1701198 ◽

2019 ◽

Vol 52 (3) ◽

pp. 207-212

Author(s):

Taeeun Kim ◽

Seung Cheol Lee ◽

Min Jae Kim ◽

Jiwon Jung ◽

Heungsup Sung ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Blood Culture ◽

Clinical Significance ◽

Positive Blood Culture

Download Full-text

ATG Use Is Associated with Frequent Occurrence of Positive Blood Cultures in Patients in the Early Phase After Hematopoietic Stem Cell Transplantation

Blood ◽

10.1182/blood.v118.21.4564.4564 ◽

2011 ◽

Vol 118 (21) ◽

pp. 4564-4564

Author(s):

Marek Seweryn ◽

Urszula Jarosz ◽

Malgorzata Krawczyk-Kulis ◽

Miroslaw Markiewicz ◽

Grzegorz Helbig ◽

...

Keyword(s):

Stem Cell ◽

Hematopoietic Stem Cell Transplantation ◽

Blood Culture ◽

Stem Cell Transplantation ◽

Positive Blood Culture ◽

Blood Cultures ◽

Gram Negative Bacteria ◽

Hematopoietic Stem ◽

Gram Negative ◽

Gram Positive Bacteria

Abstract Abstract 4564 Background: Infectious complications remain an important cause of morbidity and mortality in the early phase after hematopoietic stem cell transplantation (HSCT). Aim: The aim of this study was to assess the frequency of positive blood cultures and its potential correlation with different studied parameters in large patient population studied in the first 30 days after HSCT. Material and methods: 431 patients at median age of 47 years (range 18–85) transplanted between 2009–2011 for hematological and non-hematological malignancies were included in our analysis. There were 242 males and 189 females. Results: The indications for autologous and allogeneic HSCT were following: AML – 105 (24%), NHL – 86 (20%), MM – 75 (17,5%), HL – 48 (11%), ALL – 40 (9%), MDS – 17 (4%), AA – 15 (3,5%), CML – 12 (2,8%), PNH – 11 (2,6%), connective tissue diseases – 5 (1,2%), CLL – 3 (0,7%) and other – 14 (3,2%). The following transplant procedures were performed: ABCT – 213 (49%), ABMT – 3 (0,7%), alloBCT – 56 (13%), alloBMT – 21 (5%), URDBCT – 87 (20%), URDBMT – 51 (12%). Pre-transplant ATG and anti-CD52 antibody were used in 142 (33%) and 5 (1.2%) patients, respectively. Amongst 431 transplanted patients, 495 blood cultures were collected; range 0–8 (median 1). Eighty seven blood samples were positive (17,6%). The following pathogens were detected: gram-positive bacteria in 48% (n=42), gram-negative bacteria in 38% (n=33), fungi in 1% (n=1) and both G(+) and G(−) bacteria in 13%(n=11). The gram-positive bacteria included: Staphylococcus epidermidis: 21 (50%), Micrococcus spp: 4 (9%), Enterococcus faecium: 3 (7%), Enterococcus faecalis: 3 (7%), Streptococcus haemolyticus: 3 (7%). The following gram-negative bacteria were found: Enterobacter cloacae: 10 (30%), Escherichia coli: 7 (21%), Pseudomonas aeruginosa: 5 (15%), Klebsiella pneumonia: 5 (15%). Candida albicans was detected only in one case. The use of ATG was associated with higher number of total blood draw and positive blood cultures. No significant correlation was found between the specific pathogen and the use of ATG. Male gender was associated with significantly higher number of blood sampling and with tendency to higher number of positive blood cultures. The type of conditioning regimen, the source of stem cell and the donor origin (auto vs sibling vs unrelated) did not influence the number of positive blood culture. There was tendency to higher number of blood intake, but not positive blood culture in patients transplanted in NR if compared to PR or CR. Conclusions: Positive blood cultures were positive in about 20% of patients after HSCT. Only pre-transplant ATG use was associated with the higher number of positive blood culture. Disclosures: No relevant conflicts of interest to declare.

Download Full-text