Delays in appropriate antibiotic therapy for gram-negative bloodstream infections: a multicenter, community hospital study

Bloodstream gram-negative bacterial infections in adult patients with leukemia: A retrospective review of medical records in a tertiary care hospital in Western Saudi Arabia

BACKGROUND

Patients with neutropenic cancers are at high risk of acquiring infections, especially if on chemotherapy. Gram-negative bacterial infections are associated with high mortality. This study aimed to assess clinical characteristics, outcomes, and epidemiology of gram-negative bacterial (GNB) bloodstream infections (BSI) in adult patients with leukemia.

METHODS

This single-center, retrospective study included 102 adult patients diagnosed with leukemia between 2017 and 2019. The patients' demographics, infection diagnosis, leukemia diagnosis, comorbidities, and infection outcomes were collected from electronic medical records.

RESULTS

The most common GNB were Klebsiella pneumoniae (33.3 %), Pseudomonas aeruginosa (23.5 %), and Escherichia coli (17.6 %). Additionally, 36.7 % of infections were multidrug resistant. The most common comorbidities were cardiovascular diseases (36.7 %), diabetes mellitus (33.3 %), and liver diseases (24.1 %). GNB-infected patients had a higher mortality than noninfected patients (35.3 % and 11.8 %, respectively, p = 0.005). In a multivariable analysis, patients with acute myeloid leukemia and acute lymphoid leukemia were significantly more likely to acquire GNB BSI (p = 0.01), while patients with chronic myelogenous leukemia and chronic lymphocytic leukemia had a lower likelihood of developing GNB BSI. In addition, low hemoglobin level was an independent risk factor of GNB BSI (p = 0.001). Chemotherapeutic agents showed an association with increased risk of GNB BSI.

CONCLUSIONS

Patients with acute leukemia and low hemoglobin levels have increased risk of GNB BSI, which was associated with increased mortality. Prospective studies are needed to further assess the effect of co-morbidities and chemotherapy medications on the occurrence of GNB BSI according to the type of leukemia.

Clinical Efficacy and Diagnostic Value of Metagenomic Next-Generation Sequencing for Pathogen Detection in Patients with Suspected Infectious Diseases: A Retrospective Study from a Large Tertiary Hospital

Purpose

Metagenomic next-generation sequencing (mNGS) is a powerful yet unbiased method to identify pathogens in suspected infections. However, little is known about its clinical effectiveness. The present study aimed to assess the efficacy of mNGS in routine clinical practice.

Patients and Methods

In this single-center retrospective cohort study, 518 patients with suspected infectious diseases were assessed for inclusion. Among them, each patient had undergone mNGS testing; 407 patients had undergone both microbial culture and mNGS testing. The result of mNGS testing was compared to microbial culture performed concurrently. The diagnostic performance of mNGS was evaluated using the comprehensive clinical diagnosis as the reference standard.

Results

There was a significant difference in the positive detection rates of pathogens between mNGS and culture (331/407, 81.3% vs 79/407, 19.4%, P < 0.001). The sensitivity of mNGS was much higher than the culture method (79.5% vs 21.3%, P < 0.001), especially in sample types of sputum and bronchoalveolar lavage fluid (BALF). Notably, the sensitivity of blood mNGS was relatively lower than other sample types (67.4% vs 88.9-93.8%). Pathogen cfDNA load based on standardized stringently mapped read number at the species level of microorganisms (SDSMRN) was significantly lower in blood than in other sample types from the same patient (P = 0.0003). Importantly, mNGS directly led to a change of treatment regimen in 142 (27.4%) cases, including antibiotic escalation (15.3%), antibiotic de-escalation (9.1%), and early definitive diagnosis to initiate appropriate treatment (3.1%).

Conclusion

Our in-house mNGS platform significantly improved the sensitivity for the diagnosis of infectious diseases. mNGS has the potential to improve clinical outcomes by optimizing antimicrobial therapy.

Time to appropriate antimicrobial therapy serves an independent prognostic indicator in children with nosocomial Klebsiella pneumoniae bloodstream infection

We tend to investigate the connection between time to appropriate therapy (TTAT) and prognosis in pediatric patients with nosocomial Klebsiella pneumoniae (K. pneumoniae) bloodstream infection, and find the optimal cutoff point for the empirical administration of antimicrobials. This retrospective study was conducted in Children's Hospital of Chongqing Medical University, and inpatients with nosocomial K. pneumoniae bloodstream infection were finally enrolled. We applied the Classification and Regression Tree (CART) analysis to find the TTAT cutoff point and the Logistic Regression analysis to evaluate prognostic indicators. The incidence of septic shock and mortality was 17.91% (12/67) and 13.43% (9/67), respectively. The CART-derived TTAT cutoff point was 10.7 h. The multivariate logistic regression analysis indicated delayed therapy (TTAT ≥ 10.7 h), pediatric risk of mortality (PRISM) III scores ≥ 10, time to positivity (TTP) ≤ 13 h, and requiring for invasive mechanical ventilation were independently associated with the incidence of septic shock (Odds ratio [OR] 9.87, 95% Confidence interval [CI] 1.46-66.59, P = 0.019; OR 9.69, 95% CI 1.15-81.39, P = 0.036; OR 8.28, 95% CI 1.37-50.10, P = 0.021; OR 6.52, 95% CI 1.08-39.51, P = 0.042; respectively) and in-hospital mortality (OR 22.19, 95% CI 1.25-393.94, P = 0.035; OR 40.06, 95% CI 2.32-691.35, P = 0.011; OR 22.60, 95% CI 1.78-287.27, P = 0.016; OR 12.21, 95% CI 1.06-140.67, P = 0.045; respectively).Conclusions: TTAT is an independent predictor of poor outcomes in children with nosocomial K. pneumoniae bloodstream infection. Initial appropriate antimicrobial therapy should be administrated timely and within 10.7 h from the onset of bloodstream infection is recommended.

Association of Unit Census with Delays in Antimicrobial Initiation among Ward Patients with Hospital-acquired Sepsis

Rationale: Patients with hospital-acquired sepsis (HAS) experience higher mortality and delayed care compared with those with community-acquired sepsis. Capacity strain, the extent to which demand for hospital resources exceeds availability, thus impacting patient care, is a possible mechanism underlying antimicrobial delays for HAS but has not been studied. Objectives: Assess the association of ward census with the timing of antimicrobial initiation among ward patients with HAS. Methods: This retrospective cohort study included adult patients hospitalized at five acute care hospitals between July 2017 and December 2019 who developed ward-onset HAS, distinguished from community-acquired sepsis by onset after 48 hours of hospitalization. The primary exposure was ward census, measured as the number of patients present in each ward at each hour, standardized by quarter and year. The primary outcome was time from sepsis onset to antimicrobial initiation. We used quantile regression to assess the association between ward census at sepsis onset and time to antimicrobial initiation among patients with HAS defined by Centers for Disease Control and Prevention Adult Sepsis Event criteria. We adjusted for hospital, year, quarter, age, sex, race, ethnicity, severity of illness, admission diagnosis, and service type. Results: A total of 1,672 hospitalizations included at least one ward-onset HAS episode. Median time to antimicrobial initiation after HAS onset was 4.1 hours (interquartile range, 0.4-22.3). Marginal adjusted time to antimicrobial initiation ranged from 3.6 hours (95% confidence interval [CI], 2.4-4.8 h) to 6.8 hours (95% CI, 5.3-8.4 h) at census levels 2 standard deviations (SDs) below and above the ward-specific mean, respectively. Each 1-SD increase in ward census at sepsis onset, representing a median of 2.4 patients, was associated with an increase in time to antimicrobial initiation of 0.80 hours (95% CI, 0.32-1.29 h). In sensitivity analyses, results were consistent across severity of illness and electronic health record-based sepsis definitions. Conclusions: Time to antimicrobial initiation increased with increasing census among ward patients with HAS. These findings suggest that delays in care for HAS may be related to ward capacity strain as measured by census. Additional work is needed to validate these findings and identify potential mechanisms operating through clinician behavior and care delivery processes.

Rapid species identification of pathogenic bacteria from a minute quantity exploiting three-dimensional quantitative phase imaging and artificial neural network

The healthcare industry is in dire need of rapid microbial identification techniques for treating microbial infections. Microbial infections are a major healthcare issue worldwide, as these widespread diseases often develop into deadly symptoms. While studies have shown that an early appropriate antibiotic treatment significantly reduces the mortality of an infection, this effective treatment is difficult to practice. The main obstacle to early appropriate antibiotic treatments is the long turnaround time of the routine microbial identification, which includes time-consuming sample growth. Here, we propose a microscopy-based framework that identifies the pathogen from single to few cells. Our framework obtains and exploits the morphology of the limited sample by incorporating three-dimensional quantitative phase imaging and an artificial neural network. We demonstrate the identification of 19 bacterial species that cause bloodstream infections, achieving an accuracy of 82.5% from an individual bacterial cell or cluster. This performance, comparable to that of the gold standard mass spectroscopy under a sufficient amount of sample, underpins the effectiveness of our framework in clinical applications. Furthermore, our accuracy increases with multiple measurements, reaching 99.9% with seven different measurements of cells or clusters. We believe that our framework can serve as a beneficial advisory tool for clinicians during the initial treatment of infections.

A Baker's Dozen of Top Antimicrobial Stewardship Intervention Publications in 2020

The number of articles related to antimicrobial stewardship published each year has increased significantly over the last decade. Keeping up with the literature, particularly the most innovative, well-designed, or applicable to one’s own practice area, can be challenging. The Southeastern Research Group Endeavor (SERGE-45) network reviewed antimicrobial stewardship–related, peer-reviewed literature from 2020 that detailed actionable interventions. The top 13 publications were summarized following identification using a modified Delphi technique. This article highlights the selected interventions and may serve as a key resource for teaching and training, and to identify novel or optimized stewardship opportunities within one’s institution.

Randomized Trial Evaluating Clinical Impact of RAPid IDentification and Susceptibility Testing for Gram-negative Bacteremia: RAPIDS-GN

BACKGROUND

Rapid blood culture diagnostics are of unclear benefit for patients with gram-negative bacilli (GNB) bloodstream infections (BSIs). We conducted a multicenter, randomized, controlled trial comparing outcomes of patients with GNB BSIs who had blood culture testing with standard-of-care (SOC) culture and antimicrobial susceptibility testing (AST) vs rapid organism identification (ID) and phenotypic AST using the Accelerate Pheno System (RAPID).

METHODS

Patients with positive blood cultures with Gram stains showing GNB were randomized to SOC testing with antimicrobial stewardship (AS) review or RAPID with AS. The primary outcome was time to first antibiotic modification within 72 hours of randomization.

RESULTS

Of 500 randomized patients, 448 were included (226 SOC, 222 RAPID). Mean (standard deviation) time to results was faster for RAPID than SOC for organism ID (2.7 [1.2] vs 11.7 [10.5] hours; P < .001) and AST (13.5 [56] vs 44.9 [12.1] hours; P < .001). Median (interquartile range [IQR]) time to first antibiotic modification was faster in the RAPID arm vs the SOC arm for overall antibiotics (8.6 [2.6-27.6] vs 14.9 [3.3-41.1] hours; P = .02) and gram-negative antibiotics (17.3 [4.9-72] vs 42.1 [10.1-72] hours; P < .001). Median (IQR) time to antibiotic escalation was faster in the RAPID arm vs the SOC arm for antimicrobial-resistant BSIs (18.4 [5.8-72] vs 61.7 [30.4-72] hours; P = .01). There were no differences between the arms in patient outcomes.

CONCLUSIONS

Rapid organism ID and phenotypic AST led to faster changes in antibiotic therapy for gram-negative BSIs.

CLINICAL TRIALS REGISTRATION

NCT03218397.

Optimising Treatment Outcomes for Children and Adults Through Rapid Genome Sequencing of Sepsis Pathogens. A Study Protocol for a Prospective, Multi-Centre Trial (DIRECT)

Background

Sepsis contributes significantly to morbidity and mortality globally. In Australia, 20,000 develop sepsis every year, resulting in 5,000 deaths, and more than AUD$846 million in expenditure. Prompt, appropriate antibiotic therapy is effective in improving outcomes in sepsis. Conventional culture-based methods to identify appropriate therapy have limited yield and take days to complete. Recently, nanopore technology has enabled rapid sequencing with real-time analysis of pathogen DNA. We set out to demonstrate the feasibility and diagnostic accuracy of pathogen sequencing direct from clinical samples, and estimate the impact of this approach on time to effective therapy when integrated with personalised software-guided antimicrobial dosing in children and adults on ICU with sepsis.

Methods

The DIRECT study is a pilot prospective, non-randomized multicentre trial of an integrated diagnostic and therapeutic algorithm combining rapid direct pathogen sequencing and software-guided, personalised antibiotic dosing in children and adults with sepsis on ICU.

Participants and interventions

DIRECT will collect microbiological and pharmacokinetic samples from approximately 200 children and adults with sepsis admitted to one of four ICUs in Brisbane. In Phase 1, we will evaluate Oxford Nanopore Technologies MinION sequencing direct from blood in 50 blood culture-proven sepsis patients recruited from consecutive patients with suspected sepsis. In Phase 2, a further 50 consecutive patients with suspected sepsis will be recruited in whom MinION sequencing will be combined with Bayesian software-guided (ID-ODS) personalised antimicrobial dosing.

Outcome measures

The primary outcome is time to effective antimicrobial therapy, defined as trough drug concentrations above the MIC of the pathogen. Secondary outcomes are diagnostic accuracy of MinION sequencing from whole blood, time to pathogen identification and susceptibility testing using sequencing direct from whole blood and from positive blood culture broth.

Discussion

Rapid pathogen sequencing coupled with antimicrobial dosing software has great potential to overcome the limitations of conventional diagnostics which often result in prolonged inappropriate antimicrobial therapy. Reduced time to optimal antimicrobial therapy may reduce sepsis mortality and ICU length of stay. This pilot study will yield key feasibility data to inform further, urgently needed sepsis studies. Phase 2 of the trial protocol is registered with the ANZCTR (ACTRN12620001122943).

Trial registration

Registered with the Australia New Zealand Clinical Trials Registry Number ACTRN12620001122943

Early Screening of Risk for Multidrug-Resistant Organisms in the Emergency Department in Patients With Pneumonia and Early Septic Shock: Single-Center, Retrospective Cohort Study

OBJECTIVES

Pneumonia is the fourth leading cause of death globally, with rapid progression during sepsis. Multidrug-resistant organisms (MDROs) are becoming more common with some healthcare-associated pneumonia events. Early detection of MDRO risk improves the outcomes; however, MDROs risk in pneumonia with sepsis is unknown. This study investigated the disease outcomes of pneumonia with septic shock in patients admitted in the emergency department (ED) intensive care unit (ICU), a population with a high prevalence of MDROs, after early screening of MDROs risk.

METHODS

In this retrospective cohort study, patients with pneumonia and early septic shock (n = 533) admitted to the ED at the Taipei Tzu Chi Hospital from 2013 to 2019 were selected. The study population was divided into four subgroups after the MDROs risk and screening procedure were completed within 1 or 6 h of admission. ICU mortality and multidrug antibiotic therapy were compared.

RESULTS

The high-risk MDROs groups had higher percentage of P aeruginosa than the low-risk group. Furthermore, the appropriate ED first antibiotics were higher in the 1-h subgroup than in the 6-h subgroup of the high-risk MDROs group. In multivariate analysis, the 6-h high-risk MDROs group had an adjusted odds ratio of 7.191 (95% CI: 2.911-17.767, P < 0.001) and 2.917 (95% CI: 1.456-5.847, P = 0.003) for ICU mortality and multidrug therapy in the ICU, respectively, after adjusting for other confounding factors.

CONCLUSIONS

MDRO screening within 1 h is recommended following admission of patients with pneumonia and early septic shock in the ED, especially in areas with a high prevalence of MDROs.

Impact of Location of Acquisition of Gram-Positive Bloodstream Infections on Clinical Outcomes Among Patients Admitted to Community Hospitals

Purpose

We investigated the association between location of acquisition (LOA) of gram-positive (GP) bloodstream infections (BSI) in community hospitals and clinical outcomes.

Methods

We performed a multicenter cohort study of adult inpatients with GP BSI in nine community hospitals from 2003 to 2006. LOA was defined by CDC criteria: 1) community-acquired (CA), 2) healthcare-associated (HCA) such as BSI <48 hours after admission plus hospitalization, surgery, dialysis, invasive device, or residence in a long-term care facility in the prior 12 months, and 3) hospital-acquired (HA) as BSI ≥48 hours after hospital admission.

Results

A total of 750 patients were included. Patients with HCA or HA GP BSI were significantly more likely to require assistance with ≥1 activity of daily living, have higher Charlson scores, and die during the hospitalization. Patients with HCA or HA GP BSI were more likely to have BSI due to a multidrug-resistant GP organism, but less likely to receive appropriate antibiotics within 24 hours of BSI presentation. Those with CA BSI were more likely to have a streptococcal BSI and to be discharged home following hospitalization. HA BSI was a risk factor for requiring a procedure for BSI and receiving inappropriate antibiotics within 24 hours of BSI. Both HA and HCA GP BSI were risk factors for in-hospital mortality.

Conclusion

LOA for patients with GP BSI in community hospitals was significantly associated with differences in clinical outcomes including receiving inappropriate antibiotics and in-hospital mortality. Distinguishing LOA in a patient presenting with suspected GP BSI is a critical assessment that should influence empiric treatment patterns.

Generation and selection of antibodies for a novel immunochromatographic lateral flow test to rapidly identify OXA-23-like-mediated carbapenem resistance in Acinetobacter baumannii

INTRODUCTION

The spread of carbapenem-resistant Acinetobacter baumannii has led to a worldwide healthcare problem. Carbapenem resistance in A. baumannii is mainly mediated by the acquisition of the carbapenem-hydrolyzing oxacillinase OXA-23. The phenotypic detection of carbapenem-producing A. baumannii is challenging and time-consuming. Hence, there is an unmet medical need for reliable and rapid diagnostic tools to detect OXA-23-producing Acinetobacter isolates to enable successful patient management.

AIM

Development of an immunochromatographic lateral flow test (ICT) for the rapid and reliable detection of OXA-23-producing carbapenem-resistant Acinetobacter isolates.

METHODOLOGY

For the development of an antibody-based ICT, we generated anti-OXA-23 monoclonal antibodies (MoAbs) and screened them sequentially for their ability to bind native OXA-23. Selected OXA-23-specific MoAbs were tested in different combinations for their capacity to capture and detect OXA-23His6 by sandwich enzyme-linked immunosorbent assay (ELISA) and ICT. A well-characterized collection of carbapenem-resistant Acinetobacter isolates with defined carbapenem resistance mechanisms were used to evaluate the specificity of the final OXA-23 ICT prototype.

RESULTS

The antibody pairs best suited for the sandwich ELISA format did not match the best pairs in the ICT format selected during the development process of the final prototype OXA-23 ICT. This prototype was able to differentiate between OXA-23 subfamily-mediated carbapenem resistance and carbapenem-resistant Acinetobacter isolates overexpressing other OXAs with 100  % specificity and a turnaround time of 20 min from culture plate to result.

CONCLUSION

With this rapid detection assay one can save 12-48 h of diagnostic time, which could help avoid inappropriate use of carbapenems and enable earlier intervention to control the transmission of OXA-23-producing carbapenem-resistant Acinetobacter isolates to other patients and healthcare workers.

The 2018 Lebanese Society of Infectious Diseases and Clinical Microbiology Guidelines for the use of antimicrobial therapy in complicated intra-abdominal infections in the era of antimicrobial resistance

BACKGROUND

The Lebanese Society of Infectious Diseases and Clinical Microbiology (LSIDCM) is involved in antimicrobial stewardship. In an attempt at guiding clinicians across Lebanon in regards to the proper use of antimicrobial agents, members of this society are in the process of preparing national guidelines for common infectious diseases, among which are the guidelines for empiric and targeted antimicrobial therapy of complicated intra-abdominal infections (cIAI). The aims of these guidelines are optimizing patient care based on evidence-based literature and local antimicrobial susceptibility data, together with limiting the inappropriate use of antimicrobials thus decreasing the emergence of antimicrobial resistance (AMR) and curtailing on other adverse outcomes.

METHODS

Recommendations in these guidelines are adapted from other international guidelines but modeled based on locally derived susceptibility data and on the availability of pharmaceutical and other resources.

RESULTS

These guidelines propose antimicrobial therapy of cIAI in adults based on risk factors, site of acquisition of infection, and clinical severity of illness. We recommend using antibiotic therapy targeting third-generation cephalosporin (3GC)-resistant gram negative organisms, with carbapenem sparing as much as possible, for community-acquired infections when the following risk factors exist: prior (within 90 days) exposure to antibiotics, immunocompromised state, recent history of hospitalization or of surgery and invasive procedure all within the preceding 90 days. We also recommend antimicrobial de-escalation strategy after culture results. Prompt and adequate antimicrobial therapy for cIAI reduces morbidity and mortality; however, the duration of therapy should be limited to no more than 4 days when adequate source control is achieved and the patient is clinically stable. The management of acute pancreatitis is conservative, with a role for antibiotic therapy only in specific situations and after microbiological diagnosis. The use of broad-spectrum antimicrobial agents including systemic antifungals and newly approved antibiotics is preferably restricted to infectious diseases specialists.

CONCLUSION

These guidelines represent a major step towards initiating a Lebanese national antimicrobial stewardship program. The LSIDCM emphasizes on development of a national AMR surveillance network, in addition to a national antibiogram for cIAI stratified based on the setting (community, hospital, unit-based) that should be frequently updated.

A decision support system for antibiotic prescription based on local cumulative antibiograms

BACKGROUND

Local cumulative antibiograms are useful tools with which to select appropriate empiric or directed therapies when treating infectious diseases at a hospital. However, data represented in traditional antibiograms are static, incomplete and not well adapted to decision-making.

METHODS

We propose a decision support method for empiric antibiotic therapy based on the Number Needed to Fail (NNF) measure. NNF indicates the number of patients that would need to be treated with a specific antibiotic for one to be inadequately treated. We define two new measures, Accumulated Efficacy and Weighted Accumulated Efficacy in order to determine the efficacy of an antibiotic. We carried out two experiments: the first during which there was a suspicion of infection and the patient had empiric therapy, and the second by considering patients with confirmed infection and directed therapy. The study was performed with 15,799 cultures with 356,404 susceptibility tests carried out over a four-year period.

RESULTS

The most efficient empiric antibiotics are Linezolid and Vancomycin for blood samples and Imipenem and Meropenem for urine samples. In both experiments, the efficacies of recommended antibiotics are all significantly greater than the efficacies of the antibiotics actually administered (P < 0.001). The highest efficacy is obtained when considering 2 years of antibiogram data and 80% of the cumulated prevalence of microorganisms.

CONCLUSION

This extensive study on real empiric therapies shows that the proposed method is a valuable alternative to traditional antibiograms as regards developing clinical decision support systems for antimicrobial stewardship.

Evaluation of the Accelerate Pheno™ system for rapid identification and antimicrobial susceptibility testing of Gram-negative bacteria in bloodstream infections

Identification and antimicrobial susceptibility testing (AST) are critical steps in the management of bloodstream infections. Our objective was to evaluate the performance of the Accelerate Pheno™ System, CE v1.2 software, for identification and AST of Gram-negative pathogens from positive blood culture bottles. A total of 104 bottles positive for Gram-negative bacteria collected from inpatients throughout our institution were randomly selected after Gram staining. The time-to-identification and AST results, and the raw AST results obtained by the Accelerate Pheno™ system and routine techniques (MALDI-TOF MS and VITEK®2, EUCAST guidelines) were compared. Any discrepant AST result was tested by microdilution. The Pheno™ significantly improved turn-around times for identification (5.3 versus 23.7 h; p < 0.0001) and AST (10.7 versus 35.1 h; p < 0.0001). Complete agreement between the Accelerate Pheno™ system and the MALDI-TOF MS for identification was observed for 96.2% of samples; it was 99% (98/99) for monomicrobial samples versus 40% (3/5) for polymicrobial ones. The overall categorical agreement for AST was 93.7%; it was notably decreased for beta-lactams (cefepime 84.4%, piperacillin-tazobactam 86.5%, ceftazidime 87.6%) or Pseudomonas aeruginosa (71.9%; with cefepime 33.3%, piperacillin-tazobactam 77.8%, ceftazidime 0%). Analysis of discrepant results found impaired performance of the Accelerate Pheno™ system for beta-lactams (except cefepime) in Enterobacteriales (six very major errors) and poor performance in P. aeruginosa. The Accelerate Pheno™ system significantly improved the turn-around times for bloodstream infection diagnosis. Nonetheless, improvements in the analysis of polymicrobial samples and in AST algorithms, notably beta-lactam testing in both P. aeruginosa and Enterobacteriales, are required for implementation in routine workflow.

Investigation on outcomes and bacterial distributions of liver cirrhosis patients with gram-negative bacterial bloodstream infection

Objective

The study aimed at analyzing the epidemiology and outcomes of liver cirrhosis patients undergoing gram-negative bacterial bloodstream infection.

Results

Totally 508 eligible patients were collected, with 25.79% 30-day mortality, and 58.86% patients were confirmed as nosocomial infection. The most common isolates were Escherichia coli (48.29%) and Klebsiella pneumoniae (19.29%), and multidrug-resistant isolates accounted for 36.61%. The bacterial distributions were similar between survivors and non-survivors (P>0.05), but showed close association with acquisition sites of infection (P<0.05). Nosocomial infection (HR=1.589, 95% CI=1.004-2.517), Child-Pugh grade (HR=2.471, 95% CI=1.279-4.772), septic shock (HR=1.966, 95% CI=1.228-3.146), complications (HR=3.529, 95% CI=2.140-5.818), and WBC (HR=1.065, 95% CI=1.018-1.114) were independent indicators for 30-day mortality. β-lactamase inhibitor antibiotics exerted a high antibacterial activity.

Methods

The inpatients with liver cirrhosis developed gram-negative bacterial bloodstream infection were collected. The clinical characteristics, bacterial distribution and drug sensitivity results of patients were compared according to their 30-day survival status and acquisition sites of infections. Cox regression model was applied to evaluate the risk factors for 30-day mortality.

Conclusion

Escherichia coli and Klebsiella pneumoniae are frequently isolated from gram-negative bacterial bloodstream infection episodes in cirrhosis patients. Acquisition site of infection can influence clinical characteristics and etiological distribution. β-lactamase inhibitor antibiotics may be the first choice for empirical treatments.

Predominance of healthcare-associated cases among episodes of community-onset bacteraemia due to extended-spectrum β-lactamase-producing Enterobacteriaceae

Extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-PE) are endemic pathogens worldwide. Infection with ESBL-PE may be associated with inadequate antibiotic therapy and a poor outcome. However, risk factors for ESBL-PE community-acquired infections are ill-defined. An observational multicentre study was performed in 50 hospitals to identify the prevalence of and risk factors for community-acquired ESBL-PE bacteraemia. All patients presenting with community-onset Enterobacteriaceae bacteraemia were recorded over a 2-month period (between June and November 2013). Risk factors and 14-day outcomes of patients were investigated. Among 682 Enterobacteriaceae bacteraemia episodes recorded, 58 (8.5%) were caused by ESBL-PE. The most frequent species isolated were Escherichia coli (537; 76.7%) and Klebsiella spp. (68; 9.7%), of which 49 (9.1%) and 8 (11.8%), respectively, were ESBL-producers. Most ESBL-PE episodes were healthcare-associated, and only 22 (38%) were apparently community-acquired. The main risk factor for community-acquired ESBL-PE bacteraemia was a prior hospital stay of ≥5 days within the past year. The overall 14-day survival was 90%; only 4 (6.9%) of 58 patients with ESBL-PE bacteraemia died. Inadequate initial antibiotic therapy was administered to 55% of patients with ESBL-PE bacteraemia but was not associated with increased 14-day mortality. Although many patients had community-onset ESBL-PE bacteraemia, almost two-thirds of the episodes were actually healthcare-associated, and true community-acquired ESBL-PE bacteraemia remains rare. In our essentially non-severely ill population, inappropriate initial therapy was not associated with a higher risk of mortality.

Optimization of the β LACTA test for the detection of extended-spectrum-β-lactamase-producing bacteria directly in urine samples

The β LACTA™ test (BLT) is a chromogenic test detecting resistance to third-generation cephalosporins on bacterial colonies. Some studies have shown that this test can be used directly in urine samples. The aim of this study was to determine the optimal conditions of use of this test in order to detect the ESBL-producing bacteria directly in urine samples. During a 4-months period, a total of 365 consecutive urine samples were tested with the BLT using the recommendation of the manufacturer. We isolated 56 ESBL-producing bacteria and 17 AmpC-overproducing bacteria. ESBL- and/or AmpC β-lactamase-producing bacteria isolates were systematically characterized by disc diffusion antibiotic susceptibility testing interpreted according to the guidelines of EUCAST. The sensitivity and the specificity for 3GC-resistance detection, regardless the mechanism of resistance, were, respectively, 60.3% and 100%, whereas for ESBL detection, it was, respectively, 75.4% and 99.7%. We applied then modification of the initial protocol considering urines with a bacteriuria >1000/μL, a reading time at 30 min and considering any change of the initial colour as positive. The overall sensitivity was 81% and the sensitivity for ESBL-detection raised to 95.7%.

Critical Care Updates for the Nephrologist, 2016

With improvements in supportive care, mortality from sepsis and the acute respiratory distress syndrome has declined over the past 20 years. However, mortality associated with these conditions is still high. We will review the latest clinical trial findings in these fields, along with implications for the nephrologist. Very recently, there have been significant changes with regard to the management of anterior ischemic strokes; given the high rate of cerebrovascular disease in patients with CKD or ESRD, we will review those studies here. Finally, we will comment on best care practices in the intensive care unit, which are relevant to the nephrologist.

Comparison of clinical prediction models for resistant bacteria in community-onset pneumonia

OBJECTIVES

Six recently published algorithms classify pneumonia patients presenting from the community into high- and low-risk groups for resistant bacteria. Our objective was to compare performance of these algorithms for identifying patients infected with bacteria resistant to traditional community-acquired pneumonia antibiotics.

METHODS

This was a retrospective study of consecutive adult patients diagnosed with pneumonia in an emergency department and subsequently hospitalized. Each patient was classified as high or low risk for resistant bacteria according to the following algorithms: original health care-associated pneumonia (HCAP) criteria, Summit criteria, Brito and Niederman strategy, Shorr model, Aliberti model, and Shindo model. The reference for comparison was detection of resistant bacteria, defined as methicillin-resistant Staphylococcus aureus or Gram-negative bacteria resistant to ceftriaxone or levofloxacin.

RESULTS

A total of 614 patients were studied, including 36 (5.9%) with resistant bacteria. The HCAP criteria classified 304 (49.5%) patients as high risk, with an area under the receiver operating characteristic curve (AUC) of 0.63 (95% confidence interval [CI] = 0.54 to 0.72), sensitivity of 0.69 (95% CI = 0.52 to 0.83), and specificity of 0.52 (95% CI = 0.48 to 0.56). None of the other algorithms improved both sensitivity and specificity or significantly improved the AUC. Compared to the HCAP criteria, the Shorr and Aliberti models classified more patients as high risk, resulting in higher sensitivity and lower specificity. The Shindo model classified fewer patients as high risk, with lower sensitivity and higher specificity.

CONCLUSIONS

All algorithms for identification of resistant bacteria included in this study had suboptimal performance to guide antibiotic selection. New strategies for selecting empirical antibiotics for community-onset pneumonia are necessary.

Etiology of childhood bacteremia and timely antibiotics administration in the emergency department

BACKGROUND

Bacteremia is now an uncommon presentation to the children's emergency department (ED) but is associated with significant morbidity and mortality. Its evolving etiology may affect the ability of clinicians to initiate timely, appropriate antimicrobial therapy.

METHODS

A retrospective time series analysis of bacteremia was conducted in the Alder Hey Children's Hospital ED between 2001 and 2011. Data on significant comorbidities, time to empirical therapy, and antibiotic susceptibility were recorded.

RESULTS

A total of 575 clinical episodes were identified, and Streptococcus pneumoniae (n = 109), Neisseria meningitidis (n = 96), and Staphylococcus aureus (n = 89) were commonly isolated. The rate of bacteremia was 1.42 per 1000 ED attendances (95% confidence interval: 1.31-1.53). There was an annual reduction of 10.6% (6.6%-14.5%) in vaccine-preventable infections, and an annual increase of 6.7% (1.2%-12.5%) in Gram-negative infections. The pneumococcal conjugate vaccine was associated with a 49% (32%-74%) reduction in pneumococcal bacteremia. The rate of health care-associated bacteremia increased from 0.17 to 0.43 per 1000 ED attendances (P = .002). Susceptibility to empirical antibiotics was reduced (96.3%-82.6%; P < .001). Health care-associated bacteremia was associated with an increased length of stay of 3.9 days (95% confidence interval: 2.3-5.8). Median time to antibiotics was 184 minutes (interquartile range: 63-331) and 57 (interquartile range: 27-97) minutes longer in Gram-negative bacteremia than in vaccine-preventable bacteremia.

CONCLUSIONS

Changes in the etiology of pediatric bacteremia have implications for prompt, appropriate empirical treatment. Increasingly, pediatric bacteremia in the ED is health care associated, which increases length of inpatient stay. Prompt, effective antimicrobial administration requires new tools to improve recognition, in addition to continued etiological surveillance.