Gram-negative Bacilli Bacteremia Research Articles

Impact of Implementing an Antimicrobial Stewardship Program for Optimizing Antibiotic Treatment in Gram-negative Bacilli Bacteremia.

Antibiotic Stewardship Programs (ASP) have improved empirical and directed antibiotic treatment in Gram-negative bloodstream infections. A decrease in mortality, readmission, and length of hospitalization has been reported. A pre-post-quasi-experimental study was conducted between November and April 2015-2016 (pre-intervention period), 2016-2017, 2017-2018, and 2018-2019 (post-intervention periods), to analyse the impact of ASP on empirical, directed, and entire treatment optimization, as well as mortality, readmission, and length of hospitalization, in hospitalized patients with Gram-negative bacilli (GNB) bloodstream infections. One hundred seventy-four patients were included (41 in the pre-intervention group, 38 in the first-year post-intervention group, 50 in the second-year post-intervention group, and 45 in the third-year post-intervention group). There was a significant improvement in directed treatment optimization (43.9% in the pre-intervention group, 68.4% in the first-year post-intervention group, 74% in the second-year post-intervention group, and 88.9% in the third-year post-intervention group, P <0.001), as well as in entire treatment optimization (19.5%, 34.2%, 40.0%, and 46.7%, respectively, P=0.013), with increased optimal directed (adjusted odds ratio [aOR], 3.71; 95% confidence interval [CI], 1.60-8.58) and entire treatment (aOR, 3.31; 95% CI, 1.27-8.58). Although a tendency toward improvement was observed in empirical treatment after ASP implementation, it did not reach statistical significance (41.5% vs. 57.9%, P=0.065). No changes in mortality, readmission, or length of hospitalization were detected. ASP implementation improved both directed and entire treatment optimization in patients with GNB bloodstream infections over time. Nevertheless, no improvement was found in clinical outcomes such as mortality, readmission, or length of hospitalization.

Efficacy of Continuous vs. Intermittent Administration of Cefepime in Adult ICU Patients with Gram-Negative Bacilli Bacteremia: A Randomized Double-Blind Clinical Study.

The objective of this study was to compare the continuous infusion of cefepime with the intermittent infusion in patients with sepsis caused by Gram-negative bacilli (GNB). Randomized 1:1 multicenter double-blinded placebo-controlled study with allocation concealment; multicenter study in the intensive care units of Colombia. Patients with sepsis, severe sepsis or septic shock, and GNB-suspected bacteremia. Cefepime was administered for 7 to 14 days over 30 m intermittently every 8 h over 24 h plus continuous saline solution (0.9%) (G1) or 3 g administered continuously plus saline solution every 8 h (0.9%) (G2). The percentage of clinical response at 3, 7, and 14 days, relapse at 28 days, and mortality at discharge were measured. The recruitment was stopped at the suggestion of the Institutional Review Board (IRB) following an FDA alert about cefepime. Thirty-two patients were randomized; 25 received the intervention, and GNB bacteremia was confirmed in 16 (9 G1 and 7 G2). Favorable clinical response in days 3, 7, and 14 was 88.8%, 88.8%, and 77.8% (G1) and was similar for G2 (85.7%). There were no relapses or deaths in G2, while in G1, one relapse and two deaths were observed. The results of this study support the use of cefepime for the treatment of Gram-negative infections in critically ill patients, but we could not demonstrate differences between continuous or intermittent administration because of the small sample size, given the early suspension of the study.

Host response signature trends in persistent bacteraemia and metastatic infection due to Staphylococcus aureus and Gram-negative bacilli: a prospective multicentre observational study

Background A prompt diagnosis of bacteraemia and sepsis is essential. Markers to predict the risk of persistent bacteraemia and metastatic infection are lacking. SeptiCyte RAPID is a host response assay stratifying patients according to the risk of infectious vs sterile inflammation through a scoring system (SeptiScore). In this study we explore the association between SeptiScore and persistent bacteraemia as well as metastatic and persistent infection in the context of a proven bacteraemia episode. Methods This is a prospective multicentre observational 14-month study on patients with proven bacteraemia caused by Staphylococcus aureus or Gram-negative bacilli. Samples for assessment by SeptiCyte were collected with paired blood cultures for 4 consecutive days after the index blood culture. Results We included 86 patients in the study, 40 with S. aureus and 46 with Gram-negative bacilli bacteraemia. SeptiScores over the follow-up were higher in patients with Gram-negative compared to S. aureus bacteraemia (median 6.4, IQR 5.5–7.4 vs 5.6 IQR 5.1–6.2, p = 0.002). Higher SeptiScores were found to be associated with positive blood cultures at follow-up (AUC = 0.86, 95%CI 0.68–1.00) and with a diagnosis of metastatic infection at day 1 and 2 of follow-up (AUC = 0.79, 95%CI 0.57–1.00 and AUC = 0.82, 95%CI 0.63–1.00 respectively) in the context of Gram-negative bacteraemia while no association between SeptiScore and the outcomes of interest was observed in S. aureus bacteraemia. Mixed models confirmed the association of SeptiScore with positive blood cultures at follow-up (p = 0.04) and metastatic infection (p = 0.03) in the context of Gram-negative bacteraemia but not S. aureus bacteraemia after adjusting for confounders. Conclusions SeptiScores differ in the follow-up of S. aureus and Gram-negative bacteraemia. In the setting of Gram-negative bacteraemia SeptiScore demonstrated a good negative predictive value for the outcomes of interest and might help rule out the persistence of infection defined as metastatic spread, lack of source control or persistent bacteraemia.

Bloodstream Infections: Comparison of Diagnostic Methods and Therapeutic Consequences between a Hospital in a Resource-Limited Setting and Two French Hospitals.

In recent years, the diagnosis of bloodstream infections has been complemented by rapid microbiological methods, unattainable to most clinical laboratories in resource-limited settings. We evaluated the impact of their shortage on antibiotic therapy adequacy. We conducted a prospective multicenter cohort study including 150 adult Gram-negative bacilli bacteremia episodes, evenly distributed across three university hospitals: one in Lebanon, a resource-limited setting, and two in France, a resource-rich setting. Previous colonization by multidrug-resistant organisms (MDRO) was significantly more prevalent among the Lebanese than the French group of patients (16/50 vs. 5/100; p < 0.01). Bloodstream infections by carbapenemase-producing Enterobacterales and other MDRO were higher among the Lebanese than the French group of patients (25/50 vs. 12/100; p < 0.01). For the French group, rapid identification of species and mechanisms of resistance significantly shortened turnaround time for definitive laboratory diagnosis and increased antibiotic therapy adequacy. No statistically significant differences were noted in targeted antibiotic therapy between the two groups. This study suggests that, in settings where bacterial resistance is prevalent, rapid microbiological methods have not provided any additional value. The clinical and economic impact of rapid microbiological methods will likely depend on local CPE, VRE, and other MDRO epidemiology and are areas for future research.

Risk factors for mortality in pseudomonas aeruginosa bacteremia in children

The incidence of Pseudomonas aeruginosa (P. aeruginosa) bacteremia in children ranks third to fourth among gram-negative bacilli bacteremia, which is one of the main conditional pathogens in hospitals. This study aimed to identify the clinical characteristics and risk factors of 60-day in-hospital mortality in children with P. aeruginosa bacteremia. This retrospective study was conducted in a tertiary pediatric hospital between January 2015 and December 2021 including children with P. aeruginosa bacteremia. Kaplan-Meier survival analysis was used to investigate the time-to-event outcomes. Logistic regression was used to explore the independent risk factors for 60-day mortality. Overall, 75 patients with P. aeruginosa bacteremia episodes were identified. Immunosuppression (52%) was the most common underlying condition, followed by neutropenia (50.7%) and hematological malignancies (48%). Among 75 patients with P. aeruginosa bacteremia, 25 (33.3%) had septic shock, 30 (40%) had respiratory failure, and 20 (26.7%) had liver function impairment. The 60-day in-hospital mortality was 17.3%. In multivariate analysis, independent risk factors for 60-day mortality were respiratory failure [odds ratio (OR) 39.329; 95% CI:3.212-481.48, P=0.004) and liver function impairment (OR 17.925; 95% CI:2.909-139.178, P=0.002). Respiratory failure and liver function impairment seem to be related to poor prognosis in children with P. aeruginosa bacteremia.

Predictors of Positive Repeat Blood Cultures in Patients With Gram-Negative Bacilli Bacteremia

Introduction Bloodstream infections occur commonly in the United States and are associated with significant morbidity and mortality. Bacteremia caused by gram-positive organisms has established guidelines for the use of follow-up blood cultures (FUBCs), whereas the use of FUBCs in bacteremia due to gram-negative bacilli (GNBs) does not. One study showed that positive FUBCs were more common in gram-positive coccus bacteremia (21%) than in GNB bacteremia (6%), calling into question the overall clinical utility of using FUBCs in GNB bacteremia. We investigated the factors associated with positive FUBCs in patients with GNB bacteremia in our institution to better guide clinical practice. Methods We used a case-control design for this study. We included patients 18 years or older admitted to our hospitals between January 1, 2014, and December 31, 2018, for a duration of ≥24 hours and who had a positive blood culture (BC) for GNB. Cases were defined as any patient with a positive FUBC drawn ≥24 hours after the initial positive BC. Control subjects were defined as patients with a negative FUBC after an initial positive BC. Characteristics of cases and control subjects were compared using descriptive statistics. A multivariable regression model using stepwise variable selection was used to identify factors significantly associated with having a positive FUBC. Results We identified 70 cases meeting the inclusion criteria. We compared these 70 cases with 528 control subjects. The cases and control subjects did not differ significantly in age, sex, race, or other predefined comorbid conditions. Significant predictors for having a positive FUBC included (1) organism resistance to initial antibiotic therapy (odds ratio [OR], 3.26; P = 0.035), (2) glomerular filtration rate less than 30 mL/min (OR, 2.35; P = 0.010), (3) initial admission to critical care unit (OR, 1.72; P = 0.049), (4) central line–associated infection (OR, 3.99; P = 0.004), (5) Klebsiella group infection (OR, 2.18; P = 0.015), and (6) Serratia marcescens infection (OR, 3.53; P = 0.037). Initial discordant BC was a negative predictive factor (OR, 0.44; P = 0.018). Follow-up blood culture drawn more than 48 hours after the initial positive BC had a lower likelihood of being positive than those drawn 24 to 48 hours after the initial BC (OR, 0.59; P = 0.037). Discussion We identified 6 independent risk factors for positive FUBCs as delineated previously. These factors provide guidance for further research and for future guideline development. The timing of the FUBCs had a significant impact on positivity. Follow-up blood cultures in GNB bacteremia should be obtained more than 48 hours after the initial positive BC.

Short Course of Antibiotic Therapy for Gram-Negative Bacilli Bacteremia in Patients with Cancer and Hematopoietic Stem Cell Transplantation: Less Is Possible.

Data about short courses of antibiotic therapy for Gram-negative bacilli (GNB) bacteremia in immunosuppressed patients are limited. This is a prospective observational study performed on adult patients with cancer and hematopoietic stem cell transplant (HSCT) who developed GNB bacteremia and received appropriate empirical antibiotic therapy (EAT), had a clinical response within 7 days and survived 48 h after the end of therapy. They received antibiotic therapy in the range of 7-15 days and were divided into short course, with a median of 7 days (SC), or long course, with a median of 14 days (LC). Seventy-four patients were included (SC: 36 and LC: 38). No differences were observed in baseline characteristics or in the presence of neutropenia: 58.3% vs. 60.5% (p = 0.84). Clinical presentation and microbiological characteristics were similar in SC and LC, respectively: clinical source of bacteremia 72.2% vs. 76.3% (p = 0.68); shock 2.8% vs. 10.5% (p = 0.35) and multidrug-resistant GNB 27.8% vs. 21.1% (p = 0.50). Overall, mortality was 2.8% vs. 7.9% (p = 0.61), and bacteremia relapse was 2.8% vs. 0 (p = 0.30). The length of hospitalization since bacteremia was 7 days (interquartile range (IQR), 6-15) for SC and 12 days (IQR, 7-19) (p = 0.021) for LC. In the case of patients with cancer or HSCT and GNB bacteremia who receive appropriate EAT with clinical response, 7 days of antibiotic therapy might be adequate.

Role of fluoroquinolone prophylaxis in allogeneic hematopoietic cell transplantation in regions with a high prevalence of fluoroquinolone resistance.

The role of fluoroquinolone (FQ) prophylaxis in preventing gram-negative bacilli (GNB) bacteremia, graft-versus-host disease (GVHD), and overall survival (OS) after allogeneic hematopoietic cell transplantation (allo-HCT) is debatable and may differ in settings with low and high prevalences of FQ resistance. In this study, we aimed to answer this question in regions with high FQ resistance. This single-center retrospective study included all consecutive allo-HCT recipients aged ≥12 years from 2012 to 2021. Allo-HCT recipients until 2016 were administered FQ prophylaxis (levofloxacin). After 2016, the institutional protocol was modified to no antibiotic prophylaxis. Data were retrieved from patient records for disease and transplant characteristics, the incidence of GNB bacteremia, duration of parenteral antibiotics, hospitalization duration, acute GVHD, and OS. A total of 135 allo-HCT recipients (43 in the FQ-prophylaxis cohort and 92 in the no-antibiotic prophylaxis cohort) were analyzed in this study. The two cohorts were matched for age (median, 26 vs. 24.5 years; p = 0.8). The no-antibiotic prophylaxis cohort had a higher proportion of malignant diagnoses (80% vs. 58%, p = 0.01), haploidentical transplants (46% vs. 14%, p = 0.004), and posttransplant cyclophosphamide exposure (46% vs. 14%, p = 0.003) than did the FQ cohort. Despite this, the incidence of GNB bacteremia was not significantly different between the two cohorts (37% vs. 34%, p = 0.6). There were no differences in parenteral antibiotic use or hospitalization duration, as well as the incidence of acute GVHD (53% vs. 53%, p = 0.3). The 1-year OS was similar between the two cohorts (66% vs. 67%, p = 0.6). This study shows that FQ prophylaxis did not affect the incidence of GNB bacteremia, parenteral antibiotic use, hospitalization duration, acute GVHD, and OS post-allo-HCT.

Association of Repeated Blood Cultures With Mortality in Adult Patients With Gram-Negative Bacilli Bacteremia: A Systematic Review and Meta-analysis.

Performing repeat blood cultures after an initial positive culture (ie, follow-up blood cultures [FUBCs]) in patients with gram-negative bacilli (GNB) bacteremia is controversial. We aimed to comprehensively review the association of FUBCs with improvement in patient-relevant clinical outcomes in GNB bacteremia. We performed a systematic review and random-effects meta-analysis to calculate summary effect estimates. We used hazard ratios as the effect measure. The primary outcome was 30-day or in-hospital mortality, and secondary outcomes were length of treatment and length of hospital stay. We searched PubMed, Embase, and Cochrane Central Register of Controlled Trials (Central) without language restrictions from inception to April 29, 2022. Original clinical studies evaluating the association between FUBCs and mortality in adult patients with GNB bacteremia were included. FUBC details were reviewed. Two independent reviewers used the Risk of Bias in Non-randomised Studies of Interventions tool. We identified 9 eligible retrospective studies. In total, 7778 hospitalized patients with GNB bacteremia were included. The studies were clinically heterogeneous and had a critical risk of bias. The utilization of FUBCs varied across studies (18%-89%). Random-effects meta-analysis of covariate-adjusted estimates found that FUBC use was associated with reduced mortality. Although not a result of the meta-analysis, lengths of treatment and hospital stay were longer for patients with FUBCs than for those without. Adverse events were not reported. FUBC acquisition was associated with lower mortality and longer hospital stay and treatment duration in GNB bacteremia. The risk of bias was critical, and no firm data were available to support mechanisms.

Association between follow-up blood cultures for gram-negative bacilli bacteremia and length of hospital stay and duration of antibiotic treatment: A propensity score-matched cohort study.

It remains unclear whether a follow-up blood culture (FUBC) for gram-negative bacilli (GNB) bacteremia should be routinely or selectively performed. To evaluate the value of the practice, we analyzed the association between current FUBC practices and length of stay, antibiotic treatment duration, and in-hospital mortality. Retrospective cohort study. The study was conducted in 4 acute-care hospitals in New York City. The study included hospitalized adults with GNB bacteremia between 2017 and 2018. An FUBC was defined as a blood culture performed between 24 hours and 7 days after an initial blood culture positive for GNB. Using propensity scores for FUBCs performed, patients were matched 1:1 for outcome comparison. In total, 376 hospitalized adults with GNB bacteremia met eligibility criteria. Among them, FUBCs were performed in 271 patients (72%). After propensity score matching, we analyzed 87 pairs of patients with and without an FUBC to compare outcomes. The median length of stay was longer among patients with FUBCs than patients without FUBCs (9 days vs 7 days; P = .017). The median duration of antibiotic treatment was also longer among patients with FUBCs than patients without FUBCs (8 vs 6 days; P = .007). No statistically significant difference was observed in in-hospital mortality between patients with and without an FUBC (odds ratio, 0.37; 95% confidence interval, 0.08-1.36). Current FUBC practices for GNB bacteremia were associated with prolonged length of stay and duration of antibiotic treatment. Further data to better inform selectivity criteria for FUBCs in GNB bacteremia are needed.

Performance of the new FilmArray Blood Culture Identification 2 panel and its potential impact on clinical use in patients with Gram-negative bacteremia

IntroductionRapid diagnostic tests have been developed recently for rapid species or resistance genes identification, offering the potential to improve the selection of appropriate antibiotics. The newly developed FilmArray Blood Culture Identification 2 (BCID2) panel, which can identify more species and resistance genes, such as extended-spectrum beta-lactamase, is expected to make an impact on antimicrobial practice. MethodsThe consecutive 50 inpatients with Gram-negative bacilli bacteremia were enrolled to this retrospective single-center study. In addition to the existing FilmArray Blood Culture Identification (BCID) panel, we have implemented BCID2 panel for positive blood culture. The sensitivity and specificity of BCID and BCID2 panel were respectively calculated, and a simulation study of time to effective, optimal and de-escalation therapy was performed based on BCID or BCID2 result. ResultsA total of 52 Gram-negative organisms in 50 patients were identified from blood cultures. Of these, 45 (87%) organisms were detected by BCID2 panel, which was more than BCID panel (41 organisms, 79%). BCID2 panel detected 5 CTX-M genes, which were concordant with conventional method. The time to effective therapy did not differ between BCID arm and BCID2 arm; however, the median time to optimal therapy (34 h in BCID arm and 26 h in BCID2 arm, P = 0.0007) and the median time to de-escalation therapy (42 h in BCID arm and 22 h in BCID2 arm, P = 0.0005) were significantly shortened. ConclusionsThis simulation study of BCID2 panel showed high sensitivity and specificity, and the potential impact on shortening the time to optimal and de-escalation therapy.

Importance of early diagnosis and surgical treatment of calcified amorphous tumor-related native valve endocarditis caused by Escherichia coli: a case report

BackgroundUnlike Escherichia coli bacteremia, which is common, E. coli endocarditis is uncommon, particularly in patients with native valve, leading to its delayed diagnosis.Case presentationWe present a case of infective endocarditis caused by E. coli in a 78-year-old Japanese man with type 2 diabetes, involving persistent bacteremia and vegetation on the mitral valve (measuring 18 × 4.2 mm in diameter). He presented with recurrent fever after antimicrobial treatment for pyelonephritis. He received antibiotic therapy for 6 weeks and required surgical removal of a calcified amorphous tumor and vegetation with mitral valvuloplasty 7 days after admission. Despite an episode of multiple cerebral infarctions, he recovered fully from the infection.ConclusionsFollow-up blood cultures should be performed for Gram-negative bacilli bacteremia among patients with unknown focus and an atypical clinical course after treatment. Early diagnosis and aggressive surgical intervention are paramount to achieving good clinical outcomes.

Bedside risk prediction for positive follow-up blood culture in Gram-negative bacilli bacteremia: for whom is follow-up blood culture useful?

The value of follow-up blood culture (FUBC) in Gram-negative bacteremia (GNB) management is controversial. We evaluated bedside risk predictors and their probabilities of yielding positive FUBCs in GNB. All adult patients with GNB in a 2700-bed tertiary center were retrospectively enrolled between January 2019 and December 2019. Only one initial GNB episode was included per patient. Positive FUBC was defined as isolation of the same organism in blood culture 48-72h after the initial blood culture. A total of 2216 patients with GNB were identified, of whom 34.4% underwent FUBC. Of the 645 patients with FUBCs analyzed in the study, 89 (13.8%) had positive FUBCs. In multivariate analysis, hemodialysis [adjusted odds ratio (aOR), 2.6], fever on the day of FUBCs (aOR 3.6), intravascular device (aOR 2.4), no use of in vitro active antibiotic within 24h (aOR 2.5), non-fermenting bacteria (aOR 4.7), and multidrug resistance (aOR 5.4) were independent risk factors for positive FUBCs. If microbiological results were excluded in multivariate analysis, hemodialysis, immunosuppressive treatment, fever on the day of FUBCs, and intravascular device were independent bedside risk predictors for positive FUBCs. The yield of FUBCs increased from 3.0% (95% CI 1.0-7.0) to 63.6% (95% CI 25.6-100) as the number of bedside risk predictors increased from 0 to 4. In addition, positive FUBCs were significantly associated with 30day mortality. FUBCs may not need to be routinely used for patients with GNB bacteremia, and bedside risk predictors could be helpful in identifying patients for whom FUBC is likely to be useful.

179. Follow-up Blood Cultures for Gram-negative Bacilli Bacteremia Were Associated with Prolonged Length of Hospital Stay and Duration of Antibiotic Treatment: A Propensity Score-matched Cohort Study

BackgroundIt remains unclear if follow-up blood cultures (FUBCs) for Gram-negative bacilli (GNB) bacteremia should be performed routinely to document clearance of bacteremia due to lack of evidence on the value of FUBCs for GNB bacteremia. MethodsWe conducted a retrospective, multicenter observational study at 4 acute care hospitals to examine if FUBCs are associated with length of hospital stay, duration of antibiotic treatment, and mortality of hospitalized patients with GNB bacteremia. Participants included adult patients who were hospitalized between January 2017 and December 2018 with GNB bacteremia. Patients with and without FUBCs were propensity score-matched with a 1:1. The primary outcomes were in-hospital mortality, length of hospital stay, and duration of antibiotic treatment during the hospital stay.ResultsOf the 442 hospitalized adult patients with GNB bacteremia, 381 were included in the study. Of those, FUBCs were performed in 276 patients (72%). After propensity score matching, we included 87 patients with FUBCs and 87 patients without FUBCs for comparing outcomes. The median length of stay was longer in patients with FUBCs (9 days [interquartile range, 6.0–14.0]) compared with patients without FUBCs (7 days [interquartile range, 4.5–10.5]; P=0.017). The median duration of antibiotic treatment was also longer in patients with FUBCs (8 days [interquartile range 5.5–13.0]) compared with patients without FUBCs (6 days [interquartile range, 4.0–10.0]; P=0.007). No statistically significant difference was observed in in-hospital mortality between patients with and without FUBCs (adjusted odds ratio = 0.37; 95% confidence interval, 0.081–1.36).ConclusionPerforming FUBCs for GNB bacteremia were associated with prolonged length of hospital stay and duration of antibiotic treatment but not with mortality.Disclosures All Authors: No reported disclosures

Impact of broad-spectrum antibiotic exposures and multidrug-resistant gram-negative bacteremia on hematopoietic cell transplantation outcomes.

There is a close association between the use of broad-spectrum antibiotics, gut microbiome alteration, multidrug resistant (MDR) gram-negative bacilli (GNB) bacteremia, graft versus host disease (GVHD), and mortality post-allogeneic hematopoietic cell transplantation (allo-HCT). This study reports the impact of the high use of carbapenems and colistin and MDR bacteremia pre- and post-HCT on HCT outcomes. This was a single-center, partial retrospective, and prospective study from 2016 to 2020. Both pre- and post-HCT antibiotic exposures and blood culture/sensitivity were recorded. MDR GNB was defined as either non-susceptibility to third-generation cephalosporin or carbapenems. In the absence of positive cultures, the treating physician escalated antibiotics from third-generation cephalosporins to carbapenem and/or colistin as per clinical discretion. De-escalation policy was not strictly enforced. MDR GNB bacteremia was seen in 29 of 76 (38%) of patients peri-HCT. The utilization rates for carbapenems and colistin was significantly higher in the cohort with MDR GNB bacteremia pre-HCT (70%vs. 32%, p=0.002 and 31%vs. 6.4%, p=0.007, respectively) and post-HCT (100%vs. 74.5%, p=0.002, and 55.2%vs. 8.5%, p<0.0001, respectively). The cohort with MDR GNB bacteremia had significantly more severe acute GVHD at day+100 (45%vs. 17.5%, p=0.009). The median survival was 204 days compared to not reached in the cohort without any MDR GNB bacteremia (p=0.005). This study shows pre- and post-HCT MDR GNB bacteremia is associated with an increased risk of severe acute GVHD and mortality. Patients with MDR GNB bacteremia had higher exposure to pre- and post-HCT carbapenems and colistin.

Investigation of Gram-Negative Bacilli Bacteraemia in a Tertiary Hospital in Nigeria: Epidemiology and Antimicrobial Susceptibility Pattern

Background: The re-emergence of gram-negative bacilli (GNB) as the predominant cause of bacteraemia remains a major concern, given the increasing trend of antimicrobial resistance among this group of organisms. Prompt and effective empirical antibiotic treatment is vital for preventing adverse outcomes; therefore, a good knowledge of the local bacteria profile is required. Objective: This study was designed to aid the establishment of local antibiogram and empirical treatment for GNB bacteremia in patients referred to the University of Port Harcourt Teaching Hospital (UPTH), Nigeria. Materials and Methods: A total of 230 blood samples were obtained from inpatients in different units/departments from December 2017 to November 2018. The blood cultures were processed using BACTEC 9060 automated blood culture system, and the isolates were identified using MICROBACT 12E identification kits (Oxoid, UK) at the microbiology laboratory of UPTH. Susceptibility and resistance tests were done according to CLSI guidelines. Relevant information was obtained from the laboratory request forms and patients’ clinical files. Results: The prevalence of GNB in the study was 28.9% (71/246). The distribution of GNB bacteraemia was as follows: surgical unit (26.8%), special care baby unit (SCBU) (23.9%), intensive care unit (ICU) (21.1%), and paediatric ward (8.5%). The most common source of bacteraemia was pneumonia (35.2%) followed by puerperal sepsis (15.1%) and urinary tract infection (UTI) (15.1%). Klebsiella pneumoniae was the most frequently isolated gram-negative bacillus (26.6%). The overall resistance rate of extended spectrum lactamase producing Enterobacteriaceae (ESBL) producers, carbapenemase producers, and multi-drug resistant (MDR) organisms was 32.4%, with Acinetobacter baumannii (50%) and Pseudomonas aeruginosa (27.3%) exhibiting the highest level of resistance to carbapenems. Conclusion: This study showed a high MDR rate among GNB causing bacteraemia in patients at UPTH. An urgent review of the current antimicrobial prescription policy and infection control measures is recommended.

Impact of an Antimicrobial Stewardship Program-bundled initiative utilizing Accelerate Pheno\u2122 system in the management of patients with aerobic Gram-negative bacilli bacteremia

PurposeGram-negative bacteria (GNB) are a leading cause of bloodstream infections (BSI) and management is complicated by antibiotic resistance. The Accelerate Pheno™ system (ACC) can provide rapid organism identification and antimicrobial susceptibility testing (AST).MethodsA retrospective, pre-intervention/post-intervention study was conducted to compare management of non-critically ill patients with GNB BSI before and after implementation of a bundled initiative. This bundled initiative included dissemination of a clinical decision algorithm, ACC testing on all GNB isolated from blood cultures, real-time communication of results to the Antimicrobial Stewardship Program (ASP), and prospective audit with feedback by the ASP. The pre-intervention period was January 2018 through December 2018, and the post-intervention period was May 2019 through February 2020.ResultsSeventy-seven and 129 patients were included in the pre-intervention and post-intervention cohorts, respectively. When compared with the pre-intervention group, the time from Gram stain to AST decreased from 46.1 to 6.9 h (p < 0.001), and the time to definitive therapy (TTDT) improved from 32.6 to 10.5 h (p < 0.001). Implementation led to shorter median total duration of antibiotic therapy (14.2 vs 9.5 days; p < 0.001) and mean hospital length of stay (7.9 vs 5.3 days; p = 0.047) without an increase in 30-day readmissions (22.1% vs 14%; p = 0.13).ConclusionImplementation of an ASP-bundled approach incorporating the ACC aimed at optimizing antibiotic therapy in the management GNB BSI in non-critically ill patients led to reduced TTDT, shorter duration of antibiotic therapy, and shorter hospital length of stay without adversely affecting readmission rates.

202. Implementation of an Outpatient Parenteral Antimicrobial Therapy (OPAT) Collaborative for Patients with Staphylococcus aureus or Gram-Negative Bacilli Bacteremia Requiring Home Infusion: The PANTHIR Program

Background Staphylococcus aureus (SA) and Gram-negative bacilli (GNB) bacteremia often require prolonged treatment courses due to high morbidity and mortality risk. Outpatient parenteral antibiotic therapy (OPAT) has emerged as a preferred delivery method. Few data have been published regarding the follow-up and adverse event rates among OPAT patients. We describe outcomes in patients with SA or GNB bacteremia transitioning from an academic medical center to home infusion, prompting the implementation of the Parenteral ANtimicrobial therapy Transitions to Home Infusion Review (PANTHIR) program.MethodsA retrospective chart review of adult patients with SA or GNB bacteremia at the University of Minnesota Medical Center requiring home infusion represent a 26-month period. Baseline outcomes, including 30-day hospital readmissions and adverse drug events (ADEs), were calculated. The PANTHIR program was launched as an interdisciplinary collaborative with an infectious diseases (ID) provider, pharmacists, and home infusion specialists. Core program elements include inpatient identification, ID pharmacist review, care plan documentation and communication, and OPAT program measures.ResultsThe retrospective cohort included 69 patients. 23.2% experienced a hospitalization within 30 days of discharge and 26.1% experienced an ADE (Table 1). The mean duration of therapy was 22 days. No patient received aminoglycosides and one required vancomycin. A primary goal was to improve the continuity of care for potentially life-threatening bacteremia during the vulnerable inpatient to outpatient transition. Electronic health record functionality allowed for creation of an OPAT navigator for infectious diseases (ID) pharmacist transition plan documentation, electronic communication with designated provider and home infusion pharmacist, and retrieval of focal data points for ongoing program evaluation. 28 patients have been enrolled in the PANTHIR program with outcomes data collection underway.Table 1. Retrospective data among University of Minnesota Medical Center patients hospitalized with SA or GNB bacteremia requiring home infusion on discharge. ConclusionHospital readmission rates and ADEs are frequent among patients with SA or GNB bacteremia requiring OPAT via home infusion. An ID pharmacist-directed program in collaboration with an ID provider is feasible for OPAT transitions and may serve as a roadmap for other institutions.Disclosures Dana Simonson, PharmD, BCPS, Janssen (Advisor or Review Panel member, Other Financial or Material Support, Webinar Series Speaker Fall 2019)

288. Follow-Up Blood Cultures in Gram-Negative Bacteremia: How Do They Impact Outcomes

BackgroundAs opposed to Staphylococcus. aureus bacteremia, there are no guidelines to recommend repeating blood cultures in Gram-negative bacilli bacteremia (GNB). Several studies have questioned the utility of follow-up blood cultures (FUBCs) in GNB, but the impact of this practice on clinical outcomes is not fully understood.Our aim was to study the practice of obtaining FUBCs in GNB at our institution and to assess it’s impact on clinical outcomes.MethodsWe conducted a retrospective, single-center study of adult patients, ≥ 18 years of age admitted with GNB between January 2017 and December 2018. We aimed to compare clinical outcomes in those with and without FUBCs. Data collected included demographics, comorbidities, presumed source of bacteremia and need for intensive care unit (ICU) admission. Presence of fever, hypotension /shock and white blood cell (WBC) count on the day of FUBC was recorded. The primary objective was to compare 30-day mortality between the two groups. Secondary objectives were to compare differences in 30-day readmission rate, hospital length of stay (LOS) and duration of antibiotic treatment.Mean and standard deviation were used for continuous variables, frequency and proportion were used for categorical variables. P-value < 0.05 was defined as statistically significant.Results482 patients were included, and of these, 321 (67%) had FUBCs. 96% of FUBCs were negative and 2.8% had persistent bacteremia. There was no significant difference in 30-day mortality between those with and without FUBCs (2.9% and 2.7% respectively), or in 30-day readmission rate (21.4% and 23.4% respectively). In patients with FUBCs compared to those without FUBCs, hospital LOS was longer (7 days vs 5 days, P < 0.001), and mean duration of antibiotic treatment was longer (14 days vs 11 days, P < 0.001). A higher number of patients with FUBCs needed ICU care compared to those without FUBCs (41.4% and 25.5% respectively, P < 0.001)Microbiology of index blood culture in those with and without FUBCs Outcomes in those with and without FUBCs FUBCs characteristics ConclusionObtaining FUBCs in GNB had no impact on 30-day mortality or 30-day readmission rate. It was associated with longer LOS and antibiotic duration. Our findings suggest that FUBCs in GNB are low yield and may not be recommended in all patients. Prospective studies are needed to further examine the utility of this practice in GNB.Disclosures All Authors: No reported disclosures

Gram-negative bacilli bacteremia: a 7 year retrospective study in a referral Brazilian tertiary-care teaching hospital.

Introduction. Bloodstream infection is one of the most frequent and challenging hospital-acquired infections and it is associated with high morbidity, mortality and additional use of healthcare resources.Hypothesis/Gap Statement: Bloodstream infections have consequences for the patient, such as the evolution to mortality and inappropriate empirical antibiotic prescription, especially when caused by multidrug-resistant Gram-negative bacilli.Objective. To assess the impact of bloodstream infection and the status of multidrug resistance (MDR) in the evolution of patients who received inappropriate initial antibiotic therapy.Methods. A retrospective surveillance was conducted on nosocomial bloodstream infections caused by Gram-negative bacilli (GNB) from January 2012 to December 2018 in an adult intensive care unit of a Brazilian tertiary teaching hospital.Results. We identified 270 patients with GNB nosocomial bacteremia. Non-survivors were older (with an average age of 58.8 years vs 46.9 years, P=<0.0001), presented more severe illnesses, were immunosuppressed (73.7 vs 37.6%, P=<0.0001), were more likely to have septic shock (55.8 vs 22.4%, P=<0.0001) and had an increased usage of mechanical ventilators (98.6 vs 89.6%, P=0.0013) than survivors. In a logistic regression model, inappropriate empirical antibiotic therapy was not an independent predictor of mortality, different from mechanical ventilator (P=<0.0001; OR=28.0; 95% CI=6.3-123.6), septic shock (P=0.0051; OR=2.5; 95% CI=1.3-4.9) and immunosuppression (P=0.0066; OR=2.6; 95% CI=1.3-5.2). In contrast, in a separate model, MDR was strongly associated with the prescription of inappropriate initial antibiotic therapy (P=0.0030; OR=5.3; 95% CI=1.7-16.1). The main isolated pathogens were Acinetobacter baumannii (23.6 %) and Klebsiella pneumoniae (18.7 %). The frequency of MDR organisms was high (63.7 %), especially among non-fermenting bacilli (60.9 %), highlighting A. baumannii (81.6 %) and Pseudomonas aeruginosa (41.8 %).Conclusion. Illness severity (septic shock and immunosuppression) and mechanical ventilation were identified as predictors of mortality. Additionally, MDR was a major determinant of inappropriate antibiotic empirical therapy, but not associated with mortality, and both characteristics were not statistically associated with death.