Follow-up blood cultures in E. coli and Klebsiella spp. bacteremia-opportunities for diagnostic and antimicrobial stewardship

Risk factors for positive follow-up blood cultures in Gram-negative bacteremia among immunocompromised patients with neutropenia

INTRODUCTION

Gram-negative bacillary bloodstream infection (GN-BSI) is a frequent clinical challenge among immunocompromised hosts and is associated with a high mortality. The utility of follow-up blood cultures (FUBCs) for GN-BSI in this population, particularly in the setting of neutropenia, is poorly defined.

METHODS

We conducted a single-center, retrospective cohort study between the period of July 2018 and April 2022 to investigate the utility of FUBCs and delineate risk factors for positive cultures among neutropenic patients with monomicrobial GN-BSI. Univariate logistic regression was performed to assess risk factors associated with positive FUBCs.

RESULTS

Of 206 patients, 98% had FUBCs performed, and 9% were positive. Risk factors for positive FUBCs included multidrug-resistant GN infection (OR 3.26; 95% confidence interval [CI] 1.22-8.72) and vascular catheter source (OR 4.82; CI 1.76-13.17). Among patients lacking these risk factors, the prevalence of positive FUBCs was low (2.8%) and the negative predictive value was 92%. Those with positive and negative FUBCs had similar rates of all-cause mortality (16.7% vs. 16.6%; p = .942) and microbiologic relapse (11.1% vs. 6.0%; p = .401) within 90-days of treatment completion. However, positive FUBCs were associated with prolonged hospitalization and longer duration of antimicrobial therapy.

CONCLUSION

Positive FUBCs were infrequent in neutropenic patients with GN-BSI, and their occurrence did not significantly impact mortality or microbiologic relapse. Risk factors for positive FUBCs included multidrug resistant Gram-negative infection and vascular catheter source. Prospective studies will be necessary to elucidate the benefits and risks of FUBCs when managing GN-BSI in patients with underlying immune compromise.

Effect of Follow-Up Cerebrospinal Fluid Cultures in Post-Neurosurgical Patients' Outcome with Gram-Negative Bacterial Meningitis/Encephalitis

Background

To investigate the factors associated with follow-up CSF cultures (FUCCs) in post-neurosurgical patients with gram-negative bacterial meningitis/encephalitis and the effect of FUCCs on treatment management and patient outcomes.

Methods

This single-centered retrospective cohort study enrolled post-neurosurgical patients with gram-negative bacterial meningitis/encephalitis at a tertiary-care university hospital between 2012 and 2022. The risk factors for 28-day mortality were evaluated using multivariate Cox analysis. FUCC-related risk factors were also analyzed.

Results

Among the 844 enrolled patients, 504 (59.7%) underwent FUCC, and FUCC was found to be associated with lower rates of both all-cause (hazard ratio (HR) 0.391; 95% confidence interval (CI), 0.235-0.651; p<0.001) and attributable mortality (HR 0.463; 95% CI, 0.239-0.897; p=0.023) in Post-neurosurgical patients diagnosed with Gram-negative bacterial meningitis/encephalitis. Moreover, the results of the study underscored that patients with persistent gram-negative bacterial meningitis/encephalitis had a lower all-cause/attributable short-term survival rate according to 28-day mortality Kaplan-Meier analysis (P=0.001/0.006).

Conclusion

Performing FUCC has been demonstrated to lower mortality rates in Post-neurosurgical patients suffering from Gram-negative bacterial meningitis/encephalitis. The higher mortality rate observed in patients with persistent gram-negative bacterial meningitis/encephalitis suggests that performing FUCC is a crucial component of proper patient care and management, and is therefore recommended for use by clinicians as a standard practice. This finding underscores the significance of consistent implementation of FUCC in the management and prognosis of patients with Post-neurosurgical infections.

The effect of follow-up blood cultures on mortality and antibiotic use in gram-negative bloodstream infections

BACKGROUND

Gram-negative bloodstream infections (GN-BSIs) are a significant clinical challenge. The utility of follow-up blood cultures (FUBCs) in GN-BSIs and their impact on mortality and antibiotic consumption are areas of debate. This study aimed to evaluate the effect of FUBCs on mortality and antibiotic consumption in patients with GN-BSIs.

METHODS

This single-center, retrospective study was conducted in aged > 18 years of patients with GN-BSIs. FUBC was defined as a blood culture performed 2-7 days after the first blood culture. Patients were grouped as FUBC and no FUBC and compared. A 1:1 match analysis was performed between the groups according to the SOFA score. The matched subgroup was compared for mortality risk factors with logistic regression models. The two groups were compared for the duration of effective antibiotic therapy and total antibiotic consumption (days of therapy per 1000 patient days (DOT/1000 PD)).

RESULTS

FUBC was performed in 564 (69.4%) of 812 patients. Persistent, positive and negative FUBC rates were 7.9%, 14%, and 78%, respectively. The frequency of persistent GN-BSI in patients with appropriate antibiotic therapy was 3.9%. SOFA score (OR:1.33; 95% CI, 1.23-1.44), Charlson comorbidity index score (OR:1.18; 95% CI, 1.08-1.28), hospital-acquired infections (OR:1.93; 95% CI, 1.08-3.46) and carbapenem-resistant GN-BSI (OR: 2.92; 95% CI, 1.72-4.96) were independent risk factors for mortality. No relationship was found between FUBC and mortality (p > 0.05). Duration of effective antibiotic therapy (10(4-16) vs. 15(9-20), p < 0.001) and DOT/1000 PD (1609 (1000-2178) vs. 2000 (1294-2769), p < 0.001) were longer in the FUBC group.

CONCLUSION

Routine FUBC should not be recommended because of the low prevalence of persistent infections in patients under appropriate antibiotic therapy and FUBC increases antibiotic consumption.

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

OBJECTIVE

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.

DESIGN

Retrospective cohort study.

SETTING

The study was conducted in 4 acute-care hospitals in New York City.

PATIENTS

The study included hospitalized adults with GNB bacteremia between 2017 and 2018.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

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

Background

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.

Methods

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.

Results

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.

Conclusions

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 of Follow-up Blood Cultures With Mortality in Patients With Gram-Negative Bloodstream Infections: A Systematic Review and Meta-analysis

Importance

Obtaining follow-up blood cultures (FUBCs) in patients with Staphylococcus aureus bloodstream infection (BSI) is standard practice, although its utility in patients with gram-negative bacterial BSI (GN-BSI) is unclear.

Objective

To examine whether obtaining FUBCs is associated with decreased mortality (key question [KQ] 1) and whether positive vs negative FUBCs are associated with increased mortality (KQ2).

Data Sources

MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Web of Science, and gray literature were searched from inception to March 11, 2022.

Study Selection

Two investigators used predefined eligibility criteria to independently screen titles, abstracts, and relevant full texts. Randomized clinical trials or observational studies that matched or statistically adjusted for differences in, at minimum, level of acute illness between patients in the intervention (eg, FUBCs obtained) and control (eg, FUBCs not obtained) groups were included in primary analyses. Articles published in languages other than English were excluded.

Data Extraction and Synthesis

Data abstraction and quality assessments were performed by one investigator and verified by a second investigator. Risk of bias was assessed with the Newcastle-Ottawa Scale. Effect sizes were pooled using random-effects models. The study followed the Meta-analysis of Observational Studies in Epidemiology (MOOSE) reporting guideline.

Main Outcomes and Measures

Mortality before hospital discharge or up to 30 days from the index blood culture.

Results

From 3495 studies, 15 were included (all nonrandomized). In the 5 studies (n = 4378 patients) that met criteria for the KQ1 primary analysis, obtaining FUBCs was associated with decreased mortality (hazard ratio, 0.56; 95% CI, 0.45-0.71). For KQ2, 2 studies met criteria for the primary analysis (ie, matched or statistically adjusted for differences in patients with positive vs negative FUBCs), so an exploratory meta-analysis of all 9 studies that investigated KQ2 (n = 3243 patients) was performed. Positive FUBCs were associated with increased mortality relative to negative blood cultures (odds ratio, 2.27; 95% CI, 1.54-3.34). Limitations of the literature included a lack of randomized studies and few patient subgroup analyses.

Conclusions and Relevance

In this systematic review and meta-analysis, obtaining FUBCs in patients with GN-BSI was associated with decreased mortality. The benefit of FUBCs may stem from identification of patients with positive FUBCs, which was a poor prognostic marker.