Outcome for Gram-negative bacteraemia when following restrictive empirical antibiotic guidelines

Risk factors associated with inappropriate empirical antimicrobial treatment in bloodstream infections. A cohort study

Introduction: Bloodstream infections (BSI) are a major cause of mortality all over the world. Inappropriate empirical antimicrobial treatment (i-EAT) impact on mortality has been largely reported. However, information on related factors for the election of i-EAT in the treatment of BSI in adults is lacking. The aim of the study was the identification of risk-factors associated with the use of i-EAT in BSI. Methods: A retrospective, observational cohort study, from a prospective database was conducted in a 400-bed acute-care teaching hospital including all BSI episodes in adult patients between January and December 2018. The main outcome variable was EAT appropriation. Multivariate analysis using logistic regression was performed. Results: 599 BSI episodes were included, 146 (24%) received i-EAT. Male gender, nosocomial and healthcare-associated acquisition of infection, a high Charlson Comorbidity Index (CCI) score and the isolation of multidrug resistant (MDR) microorganisms were more frequent in the i-EAT group. Adequation to local guidelines' recommendations on EAT resulted in 91% of appropriate empirical antimicrobial treatment (a-EAT). Patients receiving i-EAT presented higher mortality rates at day 14 and 30 when compared to patients with a-EAT (14% vs. 6%, p = 0.002 and 22% vs. 9%, p < 0.001 respectively). In the multivariate analysis, a CCI score ≥3 (OR 1.90 (95% CI 1.16-3.12) p = 0.01) and the isolation of a multidrug resistant (MDR) microorganism (OR 3.79 (95% CI 2.28-6.30), p < 0.001) were found as independent risk factors for i-EAT. In contrast, female gender (OR 0.59 (95% CI 0.35-0.98), p = 0.04), a correct identification of clinical syndrome prior to antibiotics administration (OR 0.26 (95% CI 0.16-0.44), p < 0.001) and adherence to local guidelines (OR 0.22 (95% CI 0.13-0.38), p < 0.001) were identified as protective factors against i-EAT. Conclusion: One quarter of BSI episodes received i-EAT. Some of the i-EAT related factors were unmodifiable (male gender, CCI score ≥3 and isolation of a MDR microorganism) but others (incorrect identification of clinical syndrome before starting EAT or the use of local guidelines for EAT) could be addressed to optimize the use of antimicrobials.

Effects of Inappropriate Administration of Empirical Antibiotics on Mortality in Adults With Bacteraemia: Systematic Review and Meta-Analysis

Introduction

Bloodstream infections are associated with high mortality rates and contribute substantially to healthcare costs, but a consensus on the prognostic benefits of appropriate empirical antimicrobial therapy (EAT) for bacteraemia is lacking.

Methods

We performed a systematic search of the PubMed, Cochrane Library, and Embase databases through July 2021. Studies comparing the mortality rates of patients receiving appropriate and inappropriate EAT were considered eligible. The quality of the included studies was assessed using Joanna Briggs Institute checklists.

Results

We ultimately assessed 198 studies of 89,962 total patients. The pooled odds ratio (OR) for the prognostic impacts of inappropriate EAT was 2.06 (P < 0.001), and the funnel plot was symmetrically distributed. Among subgroups without between-study heterogeneity (I² = 0%), those of patients with severe sepsis and septic shock (OR, 2.14), Pitt bacteraemia scores of ≥4 (OR, 1.88), cirrhosis (OR, 2.56), older age (OR, 1.78), and community-onset/acquired Enterobacteriaceae bacteraemia infection (OR, 2.53) indicated a significant effect of inappropriate EAT on mortality. The pooled adjusted OR of 125 studies using multivariable analyses for the effects of inappropriate EAT on mortality was 2.02 (P < 0.001), and the subgroups with low heterogeneity (I² < 25%) exhibiting significant effects of inappropriate EAT were those of patients with vascular catheter infections (adjusted OR, 2.40), pneumonia (adjusted OR, 2.72), or Enterobacteriaceae bacteraemia (adjusted OR, 4.35). Notably, the pooled univariable and multivariable analyses were consistent in revealing the negligible impacts of inappropriate EAT on the subgroups of patients with urinary tract infections and Enterobacter bacteraemia.

Conclusion

Although the current evidence is insufficient to demonstrate the benefits of prompt EAT in specific bacteraemic populations, we indicated that inappropriate EAT is associated with unfavorable mortality outcomes overall and in numerous subgroups. Prospective studies designed to test these specific populations are needed to ensure reliable conclusions.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, identifier: CRD42021270274.

Impact of total body weight on 30-day mortality in patients with gram-negative bacteremia

BACKGROUND

The impact of total body weight (TBW) on 30-day mortality associated with gram-negative bacteremia has not been previously evaluated.

METHODS

The cohort included 323 patients >/ = 18 years old with gram-negative bacteremia (1/1/2008-8/31/2011) who received >/ = 48 hours of antibiotics. We compared 30-day mortality of TBW <70 kg vs. >/ = 70 kg with a multivariable stepwise logistic regression adjusting for age >/ = 70 years, cancer diagnosis, and Pitt bacteremia score of >/ = 4.

RESULTS

The cohort was 57% TBW >/ = 70 kg and 43% TBW <70 kg. TBW >/ = 70 kg patients had lower 30-day mortality (11.0% vs. 16.3%), which was significant in the multivariable analysis (OR 0.45, 95% CI 0.21-0.97). Cancer and Pitt bacteremia score >/ = 4 were also independently associated with 30-day mortality. TBW was no longer significant when TBW <50 kg patients were excluded.

CONCLUSION

TBW >/ = 70 kg was associated with an improved 30-day mortality; however, the high mortality rates for patients with a TBW < 50 kg is responsible for this association.

Restrictive antibiotic stewardship associated with reduced hospital mortality in gram-negative infection

INTRODUCTION

: Antimicrobial stewardship has an important role in the control of Clostridium difficile infection (CDI) and antibiotic resistance. An important component of UK stewardship interventions is the restriction of broad-spectrum beta-lactam antibiotics and promotion of agents associated with a lower risk of CDI such as gentamicin. While the introduction of restrictive antibiotic guidance has been associated with improvements in CDI and antimicrobial resistance, evidence of the effect on outcome following severe infection is lacking.

METHODS

: In 2008, Glasgow hospitals introduced a restrictive antibiotic guideline. A retrospective before/after study assessed outcome following Gram-negative bacteraemia in the 2-year period around implementation.

RESULTS

: Introduction of restrictive antibiotic guidelines was associated with a reduction in utilization of ceftriaxone and co-amoxiclav and an increase in amoxicillin and gentamicin. Approximately 1593 episodes of bacteremia were included in the study. The mortality over 1-year following Gram-negative bacteraemia was lower in the period following guideline implementation (RR 0.852, P  = 0.045). There was no evidence of a difference in secondary outcomes including ITU admission, length of stay, readmission, recurrence of bacteraemia and need for renal replacement therapy. There was a fall in CDI (RR 0.571, P  = 0.014) and a reduction in bacterial resistance to ceftriaxone and co-amoxiclav but no evidence of an increase in gentamicin resistance after guideline implementation.

CONCLUSION

: Restrictive antibiotic guidelines were associated with a reduction in CDI and bacterial resistance but no evidence of adverse outcomes following Gram-negative bacteraemia. There was a small reduction in one year mortality.

Plant essential oils and their constituents in coping with multidrug-resistant bacteria

Antibiotic resistance is documented to be a serious problem that affects the choice of appropriate antibiotic therapy and increases the probability of unfavorable infection outcome. One of the proposed methods to cope with multidrug-resistant (MDR) bacteria is the use of alternative antibacterial treatments, which include natural antimicrobial substances such as plant essential oils (EOs). The aim of the present article is to review published studies on the activity of EOs and their constituents against MDR bacteria and to formulate perspectives for the future. In general, published studies indicate that EOs can be used as effective antiseptics against many species, including MDR bacteria, such as methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, resistant isolates of Pseudomonas aeruginosa, Klebsiella pneumoniae and others; certain EOs may potentiate the effectiveness of antibiotics against MDR bacteria; EOs can be synergistic with bacteriophages; and polymeric nanoparticles can be used for delivery of EOs and enhancement of their activity at the site of infection.

Healthcare-associated, community-acquired and hospital-acquired bacteraemic urinary tract infections in hospitalized patients: a prospective multicentre cohort study in the era of antimicrobial resistance

The clinical and microbiological characteristics of community-onset healthcare-associated (HCA) bacteraemia of urinary source are not well defined. We conducted a prospective cohort study at eight tertiary-care hospitals in Spain, from October 2010 to June 2011. All consecutive adult patients hospitalized with bacteraemic urinary tract infection (BUTI) were included. HCA-BUTI episodes were compared with community-acquired (CA) and hospital-acquired (HA) BUTI. A logistic regression analysis was performed to identify 30-day mortality risk factors. We included 667 episodes of BUTI (246 HCA, 279 CA and 142 HA). Differences between HCA-BUTI and CA-BUTI were female gender (40% vs 69%, p <0.001), McCabe score II-III (48% vs 14%, p <0.001), Pitt score ≥2 (40% vs 31%, p 0.03), isolation of extended spectrum β-lactamase-producing Enterobacteriaciae (13% vs 5%, p <0.001), median hospital stay (9 vs 7 days, p 0.03), inappropriate empirical antimicrobial therapy (21% vs 13%, p 0.02) and mortality (11.4% vs 3.9%, p 0.001). Pseudomonas aeruginosa was more frequently isolated in HA-BUTI (16%) than in HCA-BUTI (4%, p <0.001). Independent factors for mortality were age (OR 1.04; 95% CI 1.01-1.07), McCabe score II-III (OR 3.2; 95% CI 1.8-5.5), Pitt score ≥2 (OR 3.2 (1.8-5.5) and HA-BUTI OR 3.4 (1.2-9.0)). Patients with HCA-BUTI are a specific group with significant clinical and microbiological differences from patients with CA-BUTI, and some similarities with patients with HA-BUTI. Mortality was associated with patient condition, the severity of infection and hospital acquisition.

Antimicrobial stewardship in hospitals: Does it work and can we do it?

Selection of resistant pathogens by antimicrobial use is probably the most important cause of antimicrobial resistance. Antimicrobial stewardship (AMS) refers to a multifaceted approach to optimise prescribing. The benefits of AMS programmes have been widely demonstrated in terms of reductions in antimicrobial use, mortality, Clostridium difficile and other healthcare-associated infections, hospital length of stay and bacterial resistance. Several kinds of interventions (i.e. restriction of drugs, pre-authorisation of certain antimicrobials, joint clinical rounds with prescribers, implementation of guidelines and education) have shown positive results. Regrettably, in most hospitals in Latin America, Asia and Africa as well as in a significant proportion of institutions in Europe and North America, essential human and material resources are scarce or absent, and teams are neither developed nor well functioning. Despite current or potential barriers, we should start or improve our already ongoing initiatives on AMS by considering the main specific problems and act accordingly with the available human and material resources. From supervising the use of specific classes of drugs to implementing more sophisticated decision support programmes, there is a wide range of possible useful interventions.

Gram negative bacteraemia – are they preventable and what will E. coli surveillance add?

The Department of Health in England introduced mandatory reporting of Escherichia coli bacteraemia in June 2011. We sought to determine the preventability of Gram negative bacteraemias and the efficacy of using E. coli bacteraemia as a surveillance tool. A six-month prospective study evaluated the preventability of Gram negative bacteraemias. Two investigators independently classified bacteraemias as preventable or not preventable. There were 141 bacteraemias (122 episodes) in 118 patients in the study period. E. coli was the most frequently isolated organism. Thirty five episodes (28.7%) were community onset, 24 (19.7%) hospital onset and 63 (51.6%) were healthcare-associated. Three bacteraemias (2.5%) were thought to be probably preventable and 21(17.2%) were thought to be possibly preventable. Factors associated with preventability by multivariable analysis included presence of a urinary catheter or central venous catheter and dependent functional state. A significant number of Gram negative bacteraemias were thought to be preventable, especially in patients with urinary catheters and central venous catheters. Surveillance of E. coli bacteraemias is an insensitive and non-specific method for identifying preventable Gram negative bacteraemias. We propose that targeted surveillance of patients with urinary catheters and central venous catheters in situ could help reduce infections.

Community-onset healthcare-related urinary tract infections: comparison with community and hospital-acquired urinary tract infections

OBJECTIVES

To analyze the characteristics of infection, adequacy of empirical treatment and outcome of patients with community-onset healthcare-associated (HCA) urinary tract infections (UTI) and compare them with hospital (HA) and community-acquired (CA) UTI.

METHODS

Prospective observational cohort study performed at a university 600-bed hospital between July 2009 and February 2010. Patients with UTI requiring hospital admission were included. Epidemiological, clinical and outcome data were recorded.

RESULTS

251 patients were included. Patients with community-onset HCA UTI were older, had more co-morbidities and had received previous antimicrobial treatment more frequently than CA UTI (p = 0.02, p = 0.01 and p < 0.01). ESBL-Escherichia coli and Pseudomonas aeruginosa infections were more frequent in HCA than in CA UTI (p = 0.03 and p < 0.01). Inadequate empirical treatment was not significantly different between community-onset HCA and CA. Factors related to mortality were P. aeruginosa infection (OR 6.51; 95%CI: 1.01-41.73), diabetes mellitus (OR 22.66; 95%CI: 3.61-142.21), solid neoplasia (OR 22.48; 95%CI: 3.38-149.49) and age (OR 1.15; 95%CI 1.03-1.28).

CONCLUSIONS

Epidemiological, clinical and microbiological features suggest that community-onset HCA UTI is different from CA and similar to HA UTI. However, in our series inadequate empirical antimicrobial therapy and mortality were not significantly higher in community-onset HCA than in CA UTI.