bluuebunny/crossref_metadata_2025_split huggingface dataset:
1045. A Multicenter Propensity Score-Adjusted Retrospective Study for Comparison of the Outcome of Treatment With Third-Generation Cephalosporin vs. Broad-Spectrum Antibiotics for Enterobacter Bacteremia
Authors: Hayano Satoshi , Yamamoto Shungo , Hase Ryota , Toguchi Akihiro , Otsuka Yoshihito , Hosokawa Naoto 
Published: November 2018

Abstract

Background
Enterobacter spp. can develop resistance during prolonged therapy with third-generation cephalosporins (3GC: ceftriaxone, cefotaxime, or ceftazidime) because of derepression of AmpC β-lactamase. However, the clinical significance of this phenomena remains undetermined. This study aims to assess the outcome of patients with 3GC-susceptible Enterobacter bacteremia (EB) who received definite therapy with 3GC or broad-spectrum antibiotics (BSA) using propensity score analysis.

Methods
In this retrospective, cohort study conducted at two tertiary care hospitals in Japan, we determined consecutive patients with EB identified from the laboratory databases between January 2010 and December 2017. We enrolled patients with 3GC-susceptible EB treated with 3GC or BSA (defined as fourth-generation cephalosporins, carbapenems, and piperacillin/tazobactam) as definitive therapy. The primary outcome was 28-day mortality. The secondary outcome was the emergence of antimicrobial-resistant strain during antimicrobial therapy. We compared outcomes using the propensity scores and inverse-probability-weighting (IPW) adjustment to decrease the confounding by indication.

Results
We identified 320 patients with EB; of these, 191 cases were eligible (86 treated with 3GC and 105 treated with BSA). All the measured covariates were well balanced after the IPW adjustment. We observed no significant differences in the unadjusted mortality [5.8% in the 3GC group vs. 13.3% in the BSA group; risk difference, −7.5%; 95% confidence interval (CI): −15.7–0.6; P = 0.09], and the IPW-adjusted mortality (5.1% vs. 9.4%; risk difference −4.3%; 95% CI: −12.2–3.5; P = 0.3) between the groups. The results of the propensity score-matched analysis and sensitivity analysis were similar. Furthermore, we did not observe the emergence of antimicrobial resistance during antimicrobial therapy in both groups.

Conclusion
Definitive therapy with 3GC for susceptible EB was not associated with an increased risk of the 28-day mortality after adjustment for potential confounders with the propensity score analysis or with the emergence of antimicrobial-resistant strain.

Disclosures
All authors: No reported disclosures.
1049. Outcome and Impact of Empirical Antimicrobial Treatment in Bacteraemia With Bacteroides Species; A Retrospective Cohort Study in a Region of Southern Sweden
Authors: Tham Johan , Kalin Karolina , Resman Fredrik , Holm Karin 
Published: November 2018

Abstract

Background
Anaerobic infections are an important cause of bacteremia and severe Infections. Due to increasing extended spectrum β-lactamase resistance (ESBL), the treatment recommendations for anaerobic infections in Sweden have changed during the past ten years. The effects of anaerobe resistance and outcome for patients with anaerobe infections is unclear.

Methods
A retrospective cohort study was conducted in patients with bacteraemia due to Bacteroides species in the Region of Skåne between 2011 and 2015. Data on patients were reviewed from medical and microbiological records and we determined the factors associated with 28-day mortality using a multivariate regression model.

Results
Data on 454 patients were reviewed from medical and microbiological records and 389 (median age, 76 years; male, 54%) met the inclusion criteria. The 28-day all-cause mortality rate was 19% (72/389). Inadequate empirical antibiotic therapy occurred among 182 (47%) patients, and we found a trend toward that inadequate antibiotic treatment increased the 28-day mortality (P = 0.055). The frequency of bacteraemia with Bacteroides increased during the period of time and Bacteroides fragilis was the most common bacteria, 55% (212/389). The resistance against piperacillin/tazobactam was higher than in many other studies and among the different Bacteroides isolates that were resistant to piperacillin/tazobactam, Bacteroides thetaiotamicron was the most prevalent with 60% (50/83) being resistant. Piperacillin/tazobactam was the frequently used antimicrobial agent against Bacteroides infections and the utilization was increasing. We did not find any resistance among the Bacteroides isolates against metronidazole and only three isolates were resistant against carbapenems.

Conclusion
Anaerobe resistance is an increasing issue and especially against the most common antibiotic treatment, piperacillin/tazobactam. Early recognition and appropriate treatment is important to avoid proliferation of these increasing bacteria since inadequate treatment increased the mortality.

Disclosures
All authors: No reported disclosures.
1051. Increased Mortality in Bacteremia by Enterobacter Species With Discordant Imipenem and Ertapenem Susceptibilities
Authors: Chou Andrew , Rossi Vittoria , Sucgang Richard , Hamill Richard , Zechiedrich Lynn , Trautner Barbara W 
Published: November 2018

Abstract

Background
Carbapenem-resistant Enterobacteriaceae (CRE) that are resistant only to one carbapenem have been reported, but the frequency of discordance between ertapenem and imipenem/meropenem is not known for Enterobacter species. We investigated the occurrence of discordant carbapenem susceptibilities in Enterobacter species bacteremia and the potential association with increased mortality.

Methods
We examined all cases of Enterobacter species bacteremia from January 2012 to December 2016 at the Michael E. DeBakey VA Medical Center in Houston, Texas, USA. Clinical and microbiological data were independently extracted by two investigators. Antibiotic susceptibility testing results were interpreted according to current CLSI breakpoints.

Results
We found 14/67 (20.9%) isolates had discordance between ertapenem and imipenem susceptibilities. Eight isolates were ertapenem susceptible/imipenem nonsusceptible and six isolates were ertapenem nonsusceptible/imipenem susceptible (table). Bacteremia cleared in 94.5% (52/55) of all patients who had follow-up cultures, including infection by all (13/13) isolates with discordant carbapenem susceptibilities tested. Thirty-day mortality was statistically higher in infection by isolates with discordant carbapenem susceptibilities than by isolates that were susceptible to all tested carbapenems (10% vs. 36%; P = 0.03, Fisher’s exact test). In-hospital mortality was also higher in the discordant cohort as well (12% vs. 36%; P = 0.04, Fisher’s exact test). Acute severity of illness at bacteremia onset did not differ between the groups (median Pitt bacteremia score 2 vs. 3; P = 0.11, Wilcoxon rank-sum test).

Conclusion
Bacteremia by Enterobacter species with discordant ertapenem and imipenem/meropenem susceptibilities is a relevant clinical issue, occurring in 20.9% of Enterobacter species bacteremias at our institution, and the discordance is associated with increased mortality. Whether such species can be safely treated with one carbapenem but not another is worth further investigation.
MIC: minimum inhibitory concentration; S: susceptible; I: intermediate; R: resistant;

Disclosures
B. W. Trautner, Paratek: Consultant, Consulting fee. Zambon: Consultant, Consulting fee and Research grant.
1053. Biofilm Production and Clinical Characteristics of S. maltophilia Causing Persistent or Relapsing Bacteremia
Authors: Kang Seung Ji , Oh Tae Hoon , Jung Younggon , Kim Seong Eun , Kim Uh Jin , Jang Hee-Chang , Park Kyung-Hwa , Jung Sook-In 
Published: November 2018

Abstract

Background
This study aimed to identify clinical or microbiological factors related to persistence or recurrence of Stenotrophomonas maltophilia bacteremia in adult patients.

Methods
S. maltophilia isolated from blood in two tertiary hospitals between 2011 and 2017 were investigated. Persistent bacteremia was defined as the consecutive blood culture positive for ≥5 days after initiation of appropriate antibiotics therapy. Relapse was defined as isolation of S. maltophilia from blood after completion of antibiotics treatment for the first episode of bacteremia. Biofilm formation was assessed in 96-well polystyrene plate with Trypticase Soy Broth using 0.5% crystal violet staining. The presence of smf-1 gene was detected by polymerase chain reaction.

Results
Of total 100 patients with S. maltophilia bacteremia, 10 of persistent, 8 of relapsing, and 46 of nonpersistent, nonrelapsing cases were investigated. The presence of indwelling urinary catheter (P = 0.011), nasogastric tube (P = 0.003), mechanical ventilator treatment (P = 0.001), and previous colonization of S. maltophilia (P = 0.016) were more frequently observed in patients with persistent bacteremia compared with nonpersistent, nonrelapsing bacteremia cases. In patients with relapsing bacteremia, hematologic malignancy (P = 0.022), neutropenia (P = 0.001), and concomitant isolation of S. maltophilia in clinical samples other than blood (P = 0.041) were more common than nonpersistent, nonrelapsing bacteremia patients. Catheter-related infection (37.0%) followed by pneumonia (28.3%) was the most common primary focus of nonpersistent, nonrelapsing bacteremia whereas pneumonia was the most frequent cause of bacteremia in both of persistent and relapsing cases (40.0% and 50.0%). Most of isolates (63 of 64) were susceptible to cotrimoxazole. The resistance to levofloxacin were comparable among isolates from persistent, relapsing and nonpersistent, nonrelapsing cases (10.0% vs. 12.5% vs. 15.2%, P = 0.988). Biofilm formation ability was not significantly different between three groups (optical density at 595, mean ± SD, 0.69 ± 0.34 vs. 0.78 ± 0.33 vs. 0.70 ± 0.33, P = 0.529). The smf-1 gene was found in all isolates.

Conclusion
More careful treatment approaches to patients with risk factors for S.maltophilia treatment failure should be warranted.

Disclosures
All authors: No reported disclosures.
1054. Biofilm Formation Among Escherichia coli Bloodstream Infection Isolates Is Associated With Source of Bacteremia and Bacterial Sequence Type
Authors: Chang Carolyn , Ruffin Felicia , Fowler Vance G , Thaden Joshua T 
Published: November 2018

Abstract

Background
The clinical impact of Escherichia coli biofilm formation is unknown.

Methods
Adults with E. coli bloodstream infections (BSI) were prospectively enrolled from 2002 to 2015. All E. coli isolates were genotyped using Multilocus sequence typing (MLST) and underwent crystal violet biofilm formation assay quantified by absorbance at 540 nm (OD540) in triplicate. Associations between biofilm formation and patient/bacterial characteristics were characterized by t-tests and ANOVA tests.

Results
Ninety-eight percent (186) of the 189 isolates formed detectable biofilms. Bacterial sequence type (ST) was associated with biofilm formation (P &lt; 0.001), as ST73 (average OD540 = 0.017) and ST393 (average OD540 = 0.016) had higher average biofilm formation while ST69 (average OD540 = 0.007) and ST405 (average OD540 = 0.002) had lower biofilm formation. E. coli isolates with non-multidrug-resistant (non-MDR) phenotype were associated with increased biofilm formation (MDR: average OD540 = 0.006; average non-MDR: OD540 = 0.01; P = 0.003). BSI isolates arising from pneumonia or urine/pyelonephritis were associated with the highest biofilm production (P = 0.04). No associations were identified between biofilm formation and route of infection, APACHE-II score, mortality, or complications of BSI.

Conclusion
In this prospective study of E. coli BSI isolates, biofilm formation was associated with ST, non-MDR phenotype, and BSI source.

Disclosures
All authors: No reported disclosures.
1056. Predicting Central Nervous System Complications in Staphylococcus aureus Bacteremia Using Clinical Scoring System
Authors: Kim Chung-Jong , Song Kyoung-Ho , Kang Chang Kyung , Choe Pyeong Gyun , Bae Ji Yun , Choi Hee Jung , Jung Younghee , Lee Seung Soon , Park Wan Beom , Bang Ji Hwan , Kim Eu Suk , Park Sang Won , Kim Nam Joong , Oh Myoung-Don , Kim Hong Bin ,   KIND Study Group
Published: November 2018

Abstract

Background
Central nervous system (CNS) complications occurring in patients with Staphylococcus aureus bacteremia (SAB) are the most severe complications. In this study, we compared clinical data of SAB patients between cases with and without CNS complication and analyzed the risk factor of CNS complications.

Methods
Data from cases with SAB occurred during 5 years at four hospitals were collected. The presence of CNS complications was confirmed by brain MRI, CT, or lumbar puncture. We excluded the cases who already had CNS lesions such as trauma, brain tumor, or cerebrovascular accident. We also excluded the cases who were died or transfer out &lt;7 days of bacteremia onset. Cases were divided into complication group or noncomplication group according to the presence of CNS complication. We compared the clinical profiles between the groups, and analyzed the risk factor of CNS complications by multivariate logistic regression analysis.

Results
A total of 1,085 cases of SAB patients were included. Among these, 43 (4%) cases were complication group (embolic infarct [n = 23], brain hemorrhage [n = 8], infarct with hemorrhage [n = 8], and brain abscess or meningitis [n = 4]), while 810 (74%) cases were noncomplication group. Two hundred and forty-one cases were excluded. The results of multivariate analysis were shown in table. When selecting by having less than three factors among SOFA &gt; 5, methicillin-susceptible, endovascular infection (weight 2), presence of metastatic infection and community onset, it helps to exclude CNS complications (AUC of ROC curve = 0.77, P &lt; 0.01, sensitivity; 67.5%, specificity: 75.5%, positive predictive value: 12.9%, negative predictive value 97.7%).

Conclusion
CNS complication could be excluded by using clinical variables

Disclosures
All authors: No reported disclosures.
1063. Impact of Rapid Organism Identification and a Standardized Algorithm on Antimicrobial Therapy in Patients With Bacteremia
Authors: Koutsari Christina , Gens Krista , Holt Jessica 
Published: November 2018

Abstract

Background
Bloodstream infection is associated with 12% to 32% mortality. The FilmArray® BCID panel is a multiplex polymerase chain reaction assay (PCR) that can rapidly identify the most common bacterial pathogens in the blood and three antimicrobial resistance genes. In April 2015, Abbott Northwestern Hospital (ANW) implemented the multiplex PCR panel and a pharmacist-driven process to assist with antibiotic tailoring. In August 2017, a standardized algorithm was approved providing first-line and second-line antimicrobial options for each microbial pathogen included in the multiplex PCR panel. The objective of this study was to compare the time from the multiplex PCR panel result to final appropriate antibiotic therapy (as defined by the standardized algorithm or when clinical decision was indicated) between pre- and post-algorithm implementation in hospitalized patients with bacteremia.

Methods
Retrospective chart review was performed in 93 randomly selected adult patients with ≥1 positive blood culture in November 2016–February 2017 (pre-algorithm) vs. 93 patients in November 2017–February 2018 (post-algorithm) at ANW.

Results
The two groups did not differ significantly in terms of age (average ~60 years), sex (45% female), intensive care unit admission on day 1 of bacteremia (~41%), infectious diseases (ID) consult within 72 hours of bacteremia (average 72%), bacteremia source, or etiologic bacteria. The median time to final appropriate antibiotic therapy in response to the multiplex PCR result was 19 hours (interquartile range, IQR 4–38 hours) pre-algorithm and 18 hours (IQR 4–31 hours) post-algorithm (P = 0.34).

Conclusion
The median time from the multiplex PCR result to final appropriate antibiotic therapy was ~19 hours pre- and post-algorithm. Previous studies showed a median of 21 hours to first appropriate de-escalation. Therefore, ANW performs very well in de-escalating antimicrobial therapy promptly. However, most of the rapidity in antibiotic change was driven by ID providers, who treated &gt;70% of patients. Opportunities for improvement exist for non-ID providers in tailoring antimicrobial therapy and for pharmacists in engaging and providing recommendations in a timely manner.

Disclosures
All authors: No reported disclosures.
1068. Evaluation of Cefazolin vs. Anti-Staphylococcal Penicillins for the Treatment of Methicillin-Susceptible Staphylococcus aureus Bloodstream Infections in Acutely-Ill Adult Patients: Results of a Systematic Review and Meta-Analysis
Authors: Lee Benjamin J , Constantino-Corpuz Janie K , Apolinario Kristel , Wang Sheila K , Nadler Barbara , Scheetz Marc H , Rhodes Nathaniel J 
Published: November 2018

Abstract

Background
Anti-staphylococcal penicillins (ASPs) have been regarded as first-line in the treatment of serious MSSA bloodstream infections (BSI) with cefazolin considered an alternative. Recent studies have suggested that infection outcomes between cefazolin and ASPs may be similar. The objective of this study was to compare the clinical efficacy and tolerability of cefazolin to ASPs for MSSA BSI.

Methods
A systematic review and meta-analysis was conducted. Articles were identified via PubMed, Web of Science, and the Cochrane Library. Studies written in English comparing cefazolin to ASPs for MSSA BSI in adult patients were included. Study quality was assessed using the Cochrane Risk of Bias Assessment Tool and the Newcastle-Ottawa Scale for prospective and retrospective studies, respectively. All review stages were independently conducted by two reviewers, with a third reviewer adjudicating any discrepancies. The fixed- or random-effects model was utilized, as appropriate. A planned subgroup analysis was conducted between high (&gt;15%) vs. low (&lt;14.9%) mortality probability as defined by logit functions applied at the study level.

Results
Nine studies were identified. Pooled data extracted from 1,726 cefazolin- and 2,716 ASP-patients indicated that cefazolin was associated with a significant reduction in treatment failure (OR: 0.70; 95% CI: 0.61–0.82; P &lt; 0.001; I2 = 14%) and crude, all-cause mortality (OR: 0.69; 95% CI: 0.59–0.81; P &lt; 0.001; I2 = 18%) compared with ASPs. Within a subset of studies (n = 6) demonstrating low mortality probability (&lt;14.9%), cefazolin therapy remained protective against failure (OR: 0.70; P &lt; 0.001; I2 = 39%) and mortality (OR: 0.70; P &lt; 0.001; I2 = 35%). Within the high mortality probability (&gt;15%) subset, no significant differences for failure or mortality were noted. The risk of adverse events was higher with ASPs (OR: 2.58; 95% CI: 1.00–6.64; P = 0.05).

Conclusion
Cefazolin was associated with significantly lower rates of failure, mortality, and treatment-related adverse events when compared with ASPs among less severely ill patients. Prospective, randomized controlled trials are needed to establish the role of these agents in serious MSSA BSI.

Disclosures
All authors: No reported disclosures.
1071. Impact of Standard vs. Prolonged Courses of Antibiotics for the Treatment of Uncomplicated Staphylococcus aureus Bacteremia (SAB) in Patients With Hematologic Malignancies
Authors: Cheung Edna , McKenzie Matt G , Colon Lydia Benitez , Kaye Keith S , Petty Lindsay , Martin Emily T , Marini Bernard L , Perissinotti Anthony J , Eschenauer Gregory , Alaniz Cesar , Wallace Katie L , Patel Twisha S 
Published: November 2018

Abstract

Background
The optimal treatment duration for uncomplicated SAB (U-SAB) is unknown in patients with hematologic malignancies. The goal of this study was to evaluate the impact of antibiotic duration on outcomes in patients with hematologic malignancies and U-SAB.

Methods
This was a multicenter, retrospective cohort study of adult patients with hematologic malignancies and U-SAB treated with standard (2 weeks) or prolonged (&gt;2 weeks) antibiotic therapy. U-SAB was defined as defervescence and culture clearance within 96 hours of index culture and the absence of: endocarditis, implanted prostheses, metastatic sites of infection, and bone/joint involvement. Patients with SAB therapy &lt;10 days and those with inadequate source control were excluded. The primary outcome was a composite global clinical cure: absence of relapse SAB, absence of SAB progression, and survival at 60 days following index SAB.

Results
Of 89 included patients, 51% received a standard antibiotic duration for U-SAB. The median age of the entire cohort was 56 and majority was male (60%). Neutropenia was present at index culture in 53% of patients, and acute leukemia (48%) and lymphoma (26%) were the most common underlying malignancies. Other baseline characteristics were similar between the two groups except more patients in the standard duration group had relapsed/refractory malignancy (51% vs. 25%, P = 0.016), central-line source (71% vs. 48%, P = 0.032), and antibiotic prophylaxis prior to index SAB (42% vs. 18%, P = 0.021). Median duration of treatment in the standard group was 15 days vs. 28 days in the prolonged duration group. No differences in global clinical cure and other clinical outcomes were seen between groups (Figure 1). On multivariable logistic regression analysis, only relapsed/refractory malignancy was identified as an independent predictor of global clinical failure (odds ratio, OR, 9.43; 95% confidence interval, CI, 1.17–76.9; P = 0.035). Duration of treatment was not associated with global clinical cure (OR, 2.92; 95% CI, 0.51–16.7; P = 0.23).

Conclusion
No differences in clinical outcomes were seen in patients with active hematologic malignancies who received 2 weeks vs. &gt;2 weeks of antibiotic therapy for the treatment of U-SAB, although confirmation of our findings in a larger study is warranted.

Disclosures
All authors: No reported disclosures.