Antimicrobial activity of cefepime-tazobactam combination against extended spectrum beta-lactamase and/or AmpC beta-lactamase- producing gram-negative bacilli

BACKGROUND

The problem of resistance to beta-lactam antibiotics, which is caused by ESBL and AmpC β-lactamases, is getting worse globally. Infections caused by bacterial isolates harboring these enzymes are difficult to treat with carbapenems being the sole effective treatment option for such infections. The objective of this study was to determine the frequency of ESBLs and AmpC-producing Gram-negative bacilli isolated from clinical specimens and to evaluate the sensitivity of cefepime-tazobactam combination against them.

METHODS

This is an observational cross-sectional study carried out on 100 Gram-negative bacilli at Theodor Bilharz Research Institute Hospital during the period from February 2015 to January 2016. ESBL production was screened by using the disc diffusion test followed by confirmation by the combined disc confirmatory test, the screening for AmpC production was conducted using the cefoxitin disc test, which was subsequently confirmed by the AmpC disc test. Isolates confirmed positive for ESBL and/ or AmpC production were investigated for their susceptibility to antibiotics.

RESULTS

Among 100 Gram-negative bacilli, 44 isolates were confirmed as ESBL producers by the combined disc confirmatory test out of 56 isolates that tested positive for ESBL production through the disc diffusion test. The presence of AmpC production was assessed using the cefoxitin disc test, 32 isolates were screened to be AmpC producers, and the AmpC disc test confirmed AmpC production in 9 isolates of them. Using the Mast® D68C set, 32 isolates were ESBL producers, 3 were AmpC producers, and 4 isolates were ESBL/AmpC co-producers. The highest sensitivity was to cefepime-tazobactam (91.48%) followed by the carbapenems.

CONCLUSION

Cefepime-tazobactam showed remarkable activity against ESBL and/or AmpC-producing Gram-negative bacilli and may be considered as a therapeutic alternative to carbapenems.

Functional and 123I-MIBG scintigraphy assessment of cardiac adrenergic dysfunction in diabetes

OBJECTIVES

To assess the agreement between clinical cardiovascular adrenergic function and cardiac adrenergic innervation in type 2 diabetes patients (T2D).

METHODS

Thirty-three patients with T2D were investigated bimodally through (1) a standardized clinical cardiovascular adrenergic assessment, evaluating adequacy of blood pressure responses to the Valsalva maneuver and (2) 123I-meta-iodobenzylguanidine (MIBG) scintigraphy assessing myocardial adrenergic innervation measured as early and delayed heart heart/mediastinum (H/M) ratio, and washout rate (WR).

RESULTS

T2D patients had significantly lower early and delayed H/M-ratios, and lower WR, compared to laboratory specific reference values. Thirteen patients had an abnormal adrenergic composite autonomic severity score (CASS > 0). Patients with abnormal CASS scores had significantly higher early H/M ratios (1.76 [1.66-1.88] vs. 1.57 [1.49-1.63], p < 0.001), higher delayed H/M ratios (1.64 [1.51:1.73] vs. 1.51 [1.40:1.61] (p = 0.02)), and lower WR (-0.13(0.10) vs -0.05(0.07), p = 0.01). Lower Total Recovery and shorter Pressure Recovery Time responses from the Valsalva maneuver was significantly correlated to lower H/M early (r = 0.55, p = 0.001 and r = 0.5, p = 0.003, respectively) and lower WR for Total Recovery (r = -0.44, p = 0.01).

CONCLUSION

The present study found impairment of sympathetic innervation in T2D patients based on parameters derived from MIBG cardiac scintigraphy (low early H/M, delayed H/M, and WR). These results confirm prior studies. We found a mechanistically inverted relationship with favourable adrenergic cardiovascular responses being significantly associated unfavourable MIBG indices for H/M early and delayed. This paradoxical relationship needs to be further explored but could indicate adrenergic hypersensitivity in cardiac sympathetic denervated T2D patients.

Development and application of an optimised Bayesian shrinkage prior for spectroscopic biomedical diagnostics

BACKGROUND AND OBJECTIVE

Classification of vibrational spectra is often challenging for biological substances containing similar molecular bonds, interfering with spectral outputs. To address this, various approaches are widely studied. However, whilst providing powerful estimations, these techniques are computationally extensive and frequently overfit the data. Shrinkage priors, which favour models with relatively few predictor variables, are often applied in Bayesian penalisation techniques to avoid overfitting.

METHODS

Using the logit-normal continuous analogue of the spike-and-slab (LN-CASS) as the shrinkage prior and modelling, we have established classification for accurate analysis, with the established system found to be faster than conventional least absolute shrinkage and selection operator, horseshoe or spike-and-slab. These were examined versus coefficient data based on a linear regression model and vibrational spectra produced via density functional theory calculations. Then applied to Raman spectra from saliva to classify the sample sex.

RESULTS

Subsequently applied to the acquired spectra from saliva, the evaluated models exhibited high accuracy (AUC>90 %) even when number of parameters was higher than the number of observations. Analyses of spectra for all Bayesian models yielded high-classification accuracy upon cross-validation. Further, for saliva sensing, LN-CASS was found to be the only classifier with 100 %-accuracy in predicting the output based on a leave-one-out cross validation.

CONCLUSIONS

With potential applications in aiding diagnosis from small spectroscopic datasets and are compatible with a range of spectroscopic data formats. As seen with the classification of IR and Raman spectra. These results are highly promising for emerging developments of spectroscopic platforms for biomedical diagnostic sensing systems.

Hybrid life-cycle and hierarchical archimedean copula analyses for identifying pathways of greenhouse gas mitigation in domestic sewage treatment systems

Electricity consumption and anaerobic reactions cause direct and indirect greenhouse gas (GHG) emissions within domestic sewage treatment systems (DSTSs). GHG emissions in DSTSs were influenced by the sewage quantity and the efficacy of treatment technologies. To address combined effects of these variables, this study presented an approach for identifying pathways for GHG mitigation within the DSTSs of cities under climate change and socio-economic development, through combining life cycle analysis (LCA) and the Hierarchical Archimedean copula (HAC) methods. The approach was innovative in the following aspects: 1) quantifying the GHG emissions of the DSTSs; 2) identifying the correlations among temperature changes, socioeconomic development, and domestic sewage quantity, and 3) predicting the future fluctuations in GHG emissions from the DSTSs. The effectiveness of the proposed approach was validated through its application to an urban agglomeration in the Pearl River Delta (PRD), China. To identify the potentials of GHG mitigation in the DSTSs, two pathways (i.e., general and optimized) were proposed according to the different technical choices for establishing facilities from 2021 to 2030. The results indicated that GHG emissions from the DSTS in the PRD were [3.01, 4.96] Mt CO2eq in 2021, with substantial contributions from Shenzhen and Guangzhou. Moreover, GHG emissions from the sewage treatment facilities based on Anaerobic-Anoxic-Axic (AAO) technology were higher than those based on other technologies. Under the optimized pathway, GHG emissions, contributed by the technologies of Continuous Cycle Aeration System (CASS) and Oxidation Ditch (OD), were the lowest. Through the results of correlation analysis, the impact of socioeconomic development on domestic sewage quantities was more significant than that of climate change. Domestic sewage quantities in the cities of the PRD would increase by 4.10%-28.38%, 17.14%-26.01%, and 18.15%-26.50% from 2022 to 2030 under three Representative Concentration Pathways (RCPs) 2.6, 4.5, and 8.5. These findings demonstrated that the capacities of domestic sewage treatment facilities in most cities of the PRD should be substantially improved from 0.12 to 2.99 times between 2022 and 2030. Under the optimized pathway, the future GHG emissions of the CASS method would be the lowest, followed by the OD method.

Assessing psychometric properties of the Turkish version of the Diabetes Caregiver Activity and Support Scale (D-CASS)

AIM

The study was a methodological conducted to evaluate the validity and reliability of the Turkish version of the Diabetes Caregiver Activity and Support Scale (D-CASS).

METHODS

This study was included on 272 individuals who cared for patients diagnosed with type 2 diabetes at least one year ago. Language, content, internal criterion, construct-concept validity were used to test the validity of the scale, and cronbach alpha, item-scale correlation, and test-retest were used to test the reliability.

RESULTS

The CVI was 0.95. The study was conducted with 272(60.3% female, 39.7% male) caregivers of individuals with type 2 diabetes. The study was found four week test-retest reliability with r = 0.70, p < 0001. The factor loadings of the scale items are between 0.77 and 0.95. The single factor obtained explains 75% of the total variance. The scale was found to have a high degree of reliability (Cronbach alpha=0.95).

CONCLUSION

The activities and supportive behaviours scale of caregivers of individuals with type 2 diabetes(D-CASS) is a valid and reliable measurement tool that can be used for the Turkish population.

Mismatch between subjective and objective dysautonomia

Autonomic symptom questionnaires are frequently used to assess dysautonomia. It is unknown whether subjective dysautonomia obtained from autonomic questionnaires correlates with objective dysautonomia measured by quantitative autonomic testing. The objective of our study was to determine correlations between subjective and objective measures of dysautonomia. This was a retrospective cross-sectional study conducted at Brigham and Women's Faulkner Hospital Autonomic Laboratory between 2017 and 2023 evaluating the patients who completed autonomic testing. Analyses included validated autonomic questionnaires [Survey of Autonomic Symptoms (SAS), Composite Autonomic Symptom Score 31 (Compass-31)] and standardized autonomic tests (Valsalva maneuver, deep breathing, sudomotor, and tilt test). The autonomic testing results were graded by a Quantitative scale for grading of cardiovascular reflexes, sudomotor tests and skin biopsies (QASAT), and Composite Autonomic Severity Score (CASS). Autonomic testing, QASAT, CASS, and SAS were obtained in 2627 patients, and Compass-31 in 564 patients. The correlation was strong between subjective instruments (SAS vs. Compass-31, r = 0.74, p < 0.001) and between objective instruments (QASAT vs. CASS, r = 0.81, p < 0.001). There were no correlations between SAS and QASAT nor between Compass-31 and CASS. There continued to be no correlations between subjective and objective instruments for selected diagnoses (post-acute sequelae of COVID-19, n = 61; postural tachycardia syndrome, 211; peripheral autonomic neuropathy, 463; myalgic encephalomyelitis/chronic fatigue syndrome, 95; preload failure, 120; post-treatment Lyme disease syndrome, 163; hypermobile Ehlers-Danlos syndrome, 213; neurogenic orthostatic hypotension, 86; diabetes type II, 71, mast cell activation syndrome, 172; hereditary alpha tryptasemia, 45). The lack of correlation between subjective and objective instruments highlights the limitations of the commonly used questionnaires with some patients overestimating and some underestimating true autonomic deficit. The diagnosis-independent subjective-objective mismatch further signifies the unmet need for reliable screening surveys. Patients who overestimate the symptom burden may represent a population with idiosyncratic autonomic-like symptomatology, which needs further study. At this time, the use of autonomic questionnaires as a replacement of autonomic testing cannot be recommended.

Evaluation of DermSat-7 for Assessing Treatment Satisfaction in Patients with Acne

Importance

Treatment satisfaction is important to achieving therapeutic success in patients with inflammatory dermatological diseases, such as acne.

Objective

To evaluate the structural validity, internal consistency, and construct validity of the DermSat-7, a questionnaire-based measure of treatment satisfaction, in patients with acne seen in routine clinical practice.

Design, Setting, and Participants

This cross-sectional study included adults with acne who were fluent in English and treated at an outpatient clinic at Brigham and Women's Hospital between July 2022 and May 2023. At each visit, patients completed a self-administered, patient-reported outcome questionnaire, including a patient global assessment (PGA) of their acne severity and the DermSat-7. The DermSat-7 consists of 7 items assessing 3 domains of treatment: effectiveness (3 items), convenience (3 items), and overall satisfaction (1 item). At subsequent visits, patients were asked an anchor item related to change in disease severity ("How has your acne changed compared to your last visit?") that was scored on a 7-point scale (-3 = much worse to 3 = much better). Also at each visit, a dermatologist completed the Comprehensive Acne Severity Scale (CASS).

Main Outcomes and Measures

The main outcomes were structural validity (assessed by factor analysis), internal consistency (assessed by Cronbach α), and construct validity (assessed using linear regression models and Pearson correlation coefficients).

Results

The analysis included 142 patients with acne (mean [SD] age, 25.1 [5.1] years; 96 females [67.6%]) taking acne medication who completed the DermSat-7. Exploratory factor and confirmatory factor analysis supported the unidimensionality of the 3 DermSat-7 domains. Cronbach α values of 0.89 and 0.80 supported good internal consistency in the effectiveness and convenience domains, respectively. Known-groups validity was supported by increasing DermSat-7 effectiveness and overall satisfaction scores with increasing levels of positive change in disease severity (linear regression coefficient, 7.51; 95% CI, 4.94-10.08; P < .001). Construct validity was further supported by moderate correlations with the anchor, PGA, and CASS scores (effectiveness domain: anchor r = 0.567, PGA r = -0.538, and CASS r = -0.485; overall satisfaction domain: anchor r = 0.467, PGA r = -0.486, and CASS r = -0.489).

Conclusion and Relevance

This cross-sectional study found that the DermSat-7 may be an effective tool for measuring treatment satisfaction, particularly effectiveness and overall satisfaction domains, among patients with acne. Further research is needed to examine additional measurement properties of the DermSat-7, such as content validity and interpretability, as well as to validate the DermSat-7 in other populations of patients with acne.

Two-year-long high-time-resolution apportionment of primary and secondary carbonaceous aerosols in the Los Angeles Basin using an advanced total carbon-black carbon (TC-BC(λ)) method

In recent years, carbonaceous aerosols (CA) have been recognized as a significant contributor to the concentration of particles smaller than 2.5 μm (i.e., PM_2.5), with a negative impact on public health and Earth's radiative balance. In this study, we present a method for CA apportionment based on high-time-resolution measurements of total carbon (TC), black carbon (BC), and spectral dependence of absorption coefficient using a recently developed Carbonaceous Aerosol Speciation System (CASS). Two-year-long CA measurements at two different locations within California's Los Angeles Basin are presented. CA was apportioned based on its optical absorption properties, organic or elemental carbon composition, and primary or secondary origin. We found that the secondary organic aerosols (SOA), on average, represent >50 % of CA in the study area, presumably resulting from the oxidation of anthropogenic and biogenic volatile organic components. Remarkable peaks of SOA in summer afternoons were observed, with a fractional contribution of up to 90 %. On the other hand, the peak of primary emitted CA, consisting of BC and primary organic aerosol (POA), contributed >80 % to the CA during morning rush hours on winter working days. The light absorption of BC dominated over the brown carbon (BrC), which contributed to 20 % and 10 % of optical absorption at the lower wavelength of 370 nm during winter nights and summer afternoons, respectively. The highest contribution of BrC, up to 50 %, was observed during the wildfire periods. Although the uncertainty levels can be high for some CA components (such as split between primary emitted and secondary formed BrC during winter nights), further research focused on the optical properties of CA at different locations may help to better constrain the parameters used in CA apportionment studies. We believe that the CASS system combined with the apportionment method presented in this study can offer simplified and cost-effective insights into the composition of carbonaceous aerosols.

Effect of Piperacillin-Tazobactam vs Meropenem on 30-Day Mortality for Patients With E coli or Klebsiella pneumoniae Bloodstream Infection and Ceftriaxone Resistance: A Randomized Clinical Trial

IMPORTANCE

Extended-spectrum β-lactamases mediate resistance to third-generation cephalosporins (eg, ceftriaxone) in Escherichia coli and Klebsiella pneumoniae. Significant infections caused by these strains are usually treated with carbapenems, potentially selecting for carbapenem resistance. Piperacillin-tazobactam may be an effective "carbapenem-sparing" option to treat extended-spectrum β-lactamase producers.

OBJECTIVES

To determine whether definitive therapy with piperacillin-tazobactam is noninferior to meropenem (a carbapenem) in patients with bloodstream infection caused by ceftriaxone-nonsusceptible E coli or K pneumoniae.

DESIGN, SETTING, AND PARTICIPANTS

Noninferiority, parallel group, randomized clinical trial included hospitalized patients enrolled from 26 sites in 9 countries from February 2014 to July 2017. Adult patients were eligible if they had at least 1 positive blood culture with E coli or Klebsiella spp testing nonsusceptible to ceftriaxone but susceptible to piperacillin-tazobactam. Of 1646 patients screened, 391 were included in the study.

INTERVENTIONS

Patients were randomly assigned 1:1 to intravenous piperacillin-tazobactam, 4.5 g, every 6 hours (n = 188 participants) or meropenem, 1 g, every 8 hours (n = 191 participants) for a minimum of 4 days, up to a maximum of 14 days, with the total duration determined by the treating clinician.

MAIN OUTCOMES AND MEASURES

The primary outcome was all-cause mortality at 30 days after randomization. A noninferiority margin of 5% was used.

RESULTS

Among 379 patients (mean age, 66.5 years; 47.8% women) who were randomized appropriately, received at least 1 dose of study drug, and were included in the primary analysis population, 378 (99.7%) completed the trial and were assessed for the primary outcome. A total of 23 of 187 patients (12.3%) randomized to piperacillin-tazobactam met the primary outcome of mortality at 30 days compared with 7 of 191 (3.7%) randomized to meropenem (risk difference, 8.6% [1-sided 97.5% CI, -∞ to 14.5%]; P = .90 for noninferiority). Effects were consistent in an analysis of the per-protocol population. Nonfatal serious adverse events occurred in 5 of 188 patients (2.7%) in the piperacillin-tazobactam group and 3 of 191 (1.6%) in the meropenem group.

CONCLUSIONS AND RELEVANCE

Among patients with E coli or K pneumoniae bloodstream infection and ceftriaxone resistance, definitive treatment with piperacillin-tazobactam compared with meropenem did not result in a noninferior 30-day mortality. These findings do not support use of piperacillin-tazobactam in this setting.

TRIAL REGISTRATION

anzctr.org.au Identifiers: ACTRN12613000532707 and ACTRN12615000403538 and ClinicalTrials.gov Identifier: NCT02176122.

[CME: Fusobacterium nucleatum/naviforme - a Rare but Serious Cause for Pyogenic Liver Abscesses]

CME: Fusobacterium nucleatum/naviforme - a Rare but Serious Cause for Pyogenic Liver Abscesses Abstract. Pyogenic liver abscesses belong to the most common abdominal infections. Beside the most common pathogens, also rare forms like Fusobacteria, which can also be part of the natural oropharyngeal and enteral microbiome, may be considered to cause severe forms of abscesses of the liver. Since they may be more difficult to detect, they could become a challenge during diagnosis and therapy.

Superior mesenteric venous thrombosis complicating acute appendicitis: A case report

RATIONALE

Superior mesenteric venous thrombosis (SMVT) is a rare condition that carries high mortality. Very few cases have been reported of SMVT, complicating acute appendicitis. Early recognition requires a high index of suspicion and is crucial in successful treatment of such a life-threatening condition.

PATIENT CONCERNS

A 33-year-old male presents with a 4-day history of right lower abdominal pain, nausea and subjective fever. CT scan showed acute appendicitis and a central filling defect in the superior mesenteric vein.

DIAGNOSES

Acute appendicitis complicated by SMVT.

INTERVENTIONS

Intravenous antibiotics, appendectomy, and anticoagulation.

OUTCOMES

Repeat CT scan showed successful resolution of the SMVT at a 3-month follow up.

LESSONS

Clinical awareness and high index of suspicion are essential to diagnose and manage SMVT, a serious complication of acute appendicitis.

A gratuitous β-Lactamase inducer uncovers hidden active site dynamics of the Staphylococcus aureus BlaR1 sensor domain

Increasing evidence shows that active sites of proteins have non-trivial conformational dynamics. These dynamics include active site residues sampling different local conformations that allow for multiple, and possibly novel, inhibitor binding poses. Yet, active site dynamics garner only marginal attention in most inhibitor design efforts and exert little influence on synthesis strategies. This is partly because synthesis requires a level of atomic structural detail that is frequently missing in current characterizations of conformational dynamics. In particular, while the identity of the mobile protein residues may be clear, the specific conformations they sample remain obscure. Here, we show how an appropriate choice of ligand can significantly sharpen our abilities to describe the interconverting binding poses (conformations) of protein active sites. Specifically, we show how 2-(2'-carboxyphenyl)-benzoyl-6-aminopenicillanic acid (CBAP) exposes otherwise hidden dynamics of a protein active site that binds β-lactam antibiotics. When CBAP acylates (binds) the active site serine of the β-lactam sensor domain of BlaR1 (BlaRS), it shifts the time scale of the active site dynamics to the slow exchange regime. Slow exchange enables direct characterization of inter-converting protein and bound ligand conformations using NMR methods. These methods include chemical shift analysis, 2-d exchange spectroscopy, off-resonance ROESY of the bound ligand, and reduced spectral density mapping. The active site architecture of BlaRS is shared by many β-lactamases of therapeutic interest, suggesting CBAP could expose functional motions in other β-lactam binding proteins. More broadly, CBAP highlights the utility of identifying chemical probes common to structurally homologous proteins to better expose functional motions of active sites.

Liver abscess caused by Clostridium haemolyticum infection after transarterial chemoembolization for hepatocellular carcinoma: A case report

RATIONALE

Liver abscesses caused by Clostridium species infection are extremely rare.

PATIENT CONCERNS

The authors report the first case of a liver abscess due to Clostridium haemolyticum, which occurred after transarterial chemoembolization (TACE) for hepatocellular carcinoma, in a 76-year-old woman who presented with right upper quadrant pain and fever.

DIAGNOSES

Computed tomography of the abdomen after the second TACE showed an air-filled abscess around a compact, lipiodolized lesion in the right hepatic lobe. Pus culture showed the growth of C haemolyticum.

INTERVENTIONS

Broad-spectrum antibiotics, including piperacillin/tazobactam and metronidazole, were administered, and a percutaneous 10-French pigtail catheter for pus drainage and culture was inserted in the liver abscess.

OUTCOMES

Despite administering intensive treatments, she presented with rapid deterioration in mental status, liver function, and infection markers. She was transferred to the local hospital for palliative conservative treatment.

LESSONS

Clostridia infections, including those involving C haemolyticum, are extremely rare, but should be considered as one of the causative organisms of liver abscess formation after TACE because of its rapid and fatal clinical course.

Generalized fixed drug eruption to piperacillin/tazobactam and review of literature

Fixed drug eruption (FDE) is an adverse drug reaction characterized by the development of well-circumscribed, round, dusky erythematous macules and plaques on cutaneous or mucosal surfaces. The reaction occurs on the same mucosal or cutaneous site with subsequent exposures to the offending drug. Although FDE usually manifests as a single lesion, in rare instances, more than one lesion may arise and this is referred to as a generalized eruption. Herein, we present a 31year-old man with history of cystic fibrosis who developed a generalized fixed drug eruption to piperacillin/tazobactam (Zosyn, Pfizer). We discuss our patient's course and review causes and outcomes of generalized fixed drug eruptions in the literature.

Therapeutic drug monitoring of piperacillin and tazobactam by RP-HPLC of residual blood specimens

BACKGROUND

Sepsis is a common diagnosis in critical care with inpatient mortality rates up to 50%. Sepsis care is organized around source control, antibiotics, and supportive care. Drug disposition is deranged by changes in volume of distribution and regional blood flow, as well as multiple organ failure. Thus, assuring that each patient with sepsis attains pharmacokinetic targets is challenging. There is currently no commercially available FDA-approved assay to measure piperacillin-tazobactam, very commonly used as a beta-lactam/beta-lactamase inhibitor combination antibiotic in the intensive care unit (ICU).

METHODS

Samples were prepared by ultrafiltration of plasma collected in lithium heparin Vacutainers. Separation was achieved by gradient elution on a C-18 column followed by UV detection at 214 nm. The method is validated in residual blood samples allowing investigators to exploit a waste product to develop insight into beta-lactam pharmacokinetics in the ICU.

RESULTS

Accuracy and precision were within the 25% CLIA error standard for other antibiotic assays. Free piperacillin concentrations were also in good agreement with total piperacillin concentrations measured in the same plasma by an assay in clinical use outside the United States.

CONCLUSION

We describe a method for measuring piperacillin and tazobactam that meets clinical validation standards. Quick turnaround time and excellent accuracy on a low-cost platform make this method more than adequate for use as a routine therapeutic drug monitoring tool.

Effect of Meropenem-Vaborbactam vs Piperacillin-Tazobactam on Clinical Cure or Improvement and Microbial Eradication in Complicated Urinary Tract Infection: The TANGO I Randomized Clinical Trial

IMPORTANCE

Meropenem-vaborbactam is a combination carbapenem/beta-lactamase inhibitor and a potential treatment for severe drug-resistant gram-negative infections.

OBJECTIVE

To evaluate efficacy and adverse events of meropenem-vaborbactam in complicated urinary tract infection (UTI), including acute pyelonephritis.

DESIGN, SETTING, AND PARTICIPANTS

Phase 3, multicenter, multinational, randomized clinical trial (TANGO I) conducted November 2014 to April 2016 and enrolling patients (≥18 years) with complicated UTI, stratified by infection type and geographic region.

INTERVENTIONS

Eligible patients were randomized 1:1 to receive meropenem-vaborbactam (2g/2g over 3 hours; n = 274) or piperacillin-tazobactam (4g/0.5g over 30 minutes; n = 276) every 8 hours. After 15 or more doses, patients could be switched to oral levofloxacin if they met prespecified criteria for improvement, to complete 10 days of total treatment.

MAIN OUTCOMES AND MEASURES

Primary end point for FDA criteria was overall success (clinical cure or improvement and microbial eradication composite) at end of intravenous treatment in the microbiologic modified intent-to-treat (ITT) population. Primary end point for European Medicines Agency (EMA) criteria was microbial eradication at test-of-cure visit in the microbiologic modified ITT and microbiologic evaluable populations. Prespecified noninferiority margin was -15%. Because the protocol prespecified superiority testing in the event of noninferiority, 2-sided 95% CIs were calculated.

RESULTS

Among 550 patients randomized, 545 received study drug (mean age, 52.8 years; 361 [66.2%] women; 374 [68.6%] in the microbiologic modified ITT population; 347 [63.7%] in the microbiologic evaluable population; 508 [93.2%] completed the trial). For the FDA primary end point, overall success occurred in 189 of 192 (98.4%) with meropenem-vaborbactam vs 171 of 182 (94.0%) with piperacillin-tazobactam (difference, 4.5% [95% CI, 0.7% to 9.1%]; P < .001 for noninferiority). For the EMA primary end point, microbial eradication in the microbiologic modified ITT population occurred in 128 of 192 (66.7%) with meropenem-vaborbactam vs 105 of 182 (57.7%) with piperacillin-tazobactam (difference, 9.0% [95% CI, -0.9% to 18.7%]; P < .001 for noninferiority); microbial eradication in the microbiologic evaluable population occurred in 118 of 178 (66.3%) vs 102 of 169 (60.4%) (difference, 5.9% [95% CI, -4.2% to 16.0%]; P < .001 for noninferiority). Adverse events were reported in 106 of 272 (39.0%) with meropenem-vaborbactam vs 97 of 273 (35.5%) with piperacillin-tazobactam.

CONCLUSIONS AND RELEVANCE

Among patients with complicated UTI, including acute pyelonephritis and growth of a baseline pathogen, meropenem-vaborbactam vs piperacillin-tazobactam resulted in a composite outcome of complete resolution or improvement of symptoms along with microbial eradication that met the noninferiority criterion. Further research is needed to understand the spectrum of patients in whom meropenem-vaborbactam offers a clinical advantage.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT02166476.

Propionibacterium acnes and Staphylococcus epidermidis olecranon bursitis/osteomyelitis: a case involving surgical and antibiotic treatment

This report describes a 63-year-old generally healthy male with septic olecranon bursitis caused by Propionibacterium acnes The patient sustained a small laceration after striking the posterior aspect of his left elbow on a metal railing when he was at a public swimming pool. We concluded that P. acnes was not initially detected because cultures were only kept for 5 days. Consequently, initial antibiotic treatment failed. P. acnes and Staphylococcus epidermidis grew in a subsequent tissue culture. The infection did not respond to intravenous vancomycin although soft-tissue debridements were done. This likely reflected the presence of olecranon osteomyelitis (seen on MRI scans) in addition to inadequate treatment with this antibiotic in the setting of a polymicrobial infection. Eventually, the infection was eradicated with multiple soft-tissue debridements in addition to the continuation of vancomycin with daily intravenous piperacillin/tazobactam that was added for the final 4 weeks of antibiotic treatment.

Considerable variation of trough β-lactam concentrations in older adults hospitalized with infection-a prospective observational study

In older adults, few studies confirm that adequate concentrations of antibiotics are achieved using current dosage regimens of intravenous β-lactam antibiotics. Our objective was to investigate trough concentrations of cefotaxime, meropenem, and piperacillin in older adults hospitalized with infection. We included 102 patients above 70 years of age. Total trough antibiotic concentrations were measured and related to suggested target intervals. Information on antibiotic dose, patient characteristics, and 28-day outcomes were collected from medical records and regression models were fitted. Trough concentrations for all three antibiotics exhibited considerable variation. Mean total trough concentrations for cefotaxime, meropenem, and piperacillin were 6.5 mg/L (range 0-44), 3.4 mg/L (range 0-11), and 30.2 mg/L (range 1.2-131), respectively. When a target range of non-species-related breakpoint - 5× non-species-related breakpoint was applied, only 36% of patients had both values within the target range. Regression models revealed that severe sepsis was associated with varying concentration levels and increasing age and diminishing kidney function with high concentration levels. The study was not powered to demonstrate consequences in clinical outcomes. Conclusively, in older adults treated with cefotaxime, meropenem, or piperacillin-tazobactam, trough antibiotic concentrations varied considerably. Better predictors to guide dosing regimens of β-lactam antibiotics or increased use of therapeutic drug monitoring are potential ways to address such variations.

[Antimicrobial activity of ceftolozane/tazobactam against Enterobacteriaceae and Pseudomonas aeruginosa in the Czech Republic in 2016]

OBJECTIVE

Ceftolozane/tazobactam is an antibiotic effective against Gram-negative bacteria(including Pseudomonas aeruginosa).The study aimed at determining the effectiveness of the novel antibiotic in the Czech Republic.

MATERIAL AND METHODS

The effectiveness of the antibiotic was studied in 16 Czech laboratories in 822 Enterobacteriaceae isolates (including AmpC and ESBL producers) and P. aeruginosa causing complicated intraabdominal or urinary tract infections. Minimum inhibitory concentrations were determined using the Etest. With the exception of Citrobacter freundii and Enterobacter cloacae, ceftozolane/tazobactam proved to be very effective against Enterobacteriaceae; no P. aeruginosa strain was resistant to the antibiotic.

CONCLUSION

The results confirmed good activity of ceftozolane/tazobactam in vitro against Enterobacteriaceae (Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Proteus mirabilis) and P. aeruginosa in the Czech Republic.

Genomics and Susceptibility Profiles of Extensively Drug-Resistant Pseudomonas aeruginosa Isolates from Spain

This study assessed the molecular epidemiology, resistance mechanisms, and susceptibility profiles of a collection of 150 extensively drug-resistant (XDR) Pseudomonas aeruginosa clinical isolates obtained from a 2015 Spanish multicenter study, with a particular focus on resistome analysis in relation to ceftolozane-tazobactam susceptibility. Broth microdilution MICs revealed that nearly all (>95%) of the isolates were nonsusceptible to piperacillin-tazobactam, ceftazidime, cefepime, aztreonam, imipenem, meropenem, and ciprofloxacin. Most of them were also resistant to tobramycin (77%), whereas nonsusceptibility rates were lower for ceftolozane-tazobactam (31%), amikacin (7%), and colistin (2%). Pulsed-field gel electrophoresis-multilocus sequence typing (PFGE-MLST) analysis revealed that nearly all of the isolates belonged to previously described high-risk clones. Sequence type 175 (ST175) was detected in all 9 participating hospitals and accounted for 68% (n = 101) of the XDR isolates, distantly followed by ST244 (n = 16), ST253 (n = 12), ST235 (n = 8), and ST111 (n = 2), which were detected only in 1 to 2 hospitals. Through phenotypic and molecular methods, the presence of horizontally acquired carbapenemases was detected in 21% of the isolates, mostly VIM (17%) and GES enzymes (4%). At least two representative isolates from each clone and hospital (n = 44) were fully sequenced on an Illumina MiSeq. Classical mutational mechanisms, such as those leading to the overexpression of the β-lactamase AmpC or efflux pumps, OprD inactivation, and/or quinolone resistance-determining regions (QRDR) mutations, were confirmed in most isolates and correlated well with the resistance phenotypes in the absence of horizontally acquired determinants. Ceftolozane-tazobactam resistance was not detected in carbapenemase-negative isolates, in agreement with sequencing data showing the absence of ampC mutations. The unique set of mutations responsible for the XDR phenotype of ST175 clone documented 7 years earlier were found to be conserved, denoting the long-term persistence of this specific XDR lineage in Spanish hospitals. Finally, other potentially relevant mutations were evidenced, including those in penicillin-binding protein 3 (PBP3), which is involved in β-lactam (including ceftolozane-tazobactam) resistance, and FusA1, which is linked to aminoglycoside resistance.

Ceftolozane-tazobactam activity against drug-resistant Enterobacteriaceae and Pseudomonas aeruginosa causing healthcare-associated infections in Latin America: report from an antimicrobial surveillance program (2013–2015)

This study evaluated the in vitro activity of ceftolozane-tazobactam and comparator agents tested against Latin American isolates of Enterobacteriaceae and Pseudomonas aeruginosa from patients with health care-associated infections. Ceftolozane-tazobactam is an antipseudomonal cephalosporin combined with a well-established β-lactamase inhibitor.

A total of 2415 Gram-negative organisms (537 P. aeruginosa and 1878 Enterobacteriaceae) were consecutively collected in 12 medical centers located in four Latin American countries. The organisms were tested for susceptibility by broth microdilution methods as described by the CLSI M07-A10 document and the results interpreted according to EUCAST and CLSI breakpoint criteria.

Results

Ceftolozane-tazobactam (MIC_50/90, 0.25/32 μg/mL; 84.2% susceptible) and meropenem (MIC_50/90, ≤0.06/0.12 μg/mL; 92.6% susceptible) were the most active compounds tested against Enterobacteriaceae. Among the Enterobacteriaceae isolates tested, 6.6% were carbapenem-resistant Enterobacteriaceae and 26.4% exhibited an extended-spectrum β-lactamase non-carbapenem-resistant phenotype. Whereas ceftolozane-tazobactam showed good activity against extended-spectrum beta-lactamase, non-carbapenem-resistant phenotype strains of Enterobacteriaceae (MIC_50/90, 0.5/>32 μg/mL), it lacked useful activity against strains with a (MIC_50/90, >32/>32 μg/mL; 1.6% S) carbapenem-resistant phenotype. Ceftolozane-tazobactam was the most potent (MIC_50//90, 0.5/16 μg/mL) β-lactam agent tested against P. aeruginosa isolates, inhibiting 86.8% at an MIC of ≤4 μg/mL. P. aeruginosa exhibited high rates of resistance to cefepime (16.0%), ceftazidime (23.6%), meropenem (28.3%), and piperacillin-tazobactam (16.4%).

Conclusions

Ceftolozane-tazobactam was the most active β-lactam agent tested against P. aeruginosa and demonstrated higher in vitro activity than available cephalosporins and piperacillin-tazobactam when tested against Enterobacteriaceae.

Dosing antibiotics in neonates: review of the pharmacokinetic data

Antibiotics are often used in neonates despite the absence of relevant dosing information in drug labels. For neonatal dosing, clinicians must extrapolate data from studies for adults and older children, who have strikingly different physiologies. As a result, dosing extrapolation can lead to increased toxicity or efficacy failures in neonates. Driven by these differences and recent legislation mandating the study of drugs in children and neonates, an increasing number of pharmacokinetic studies of antibiotics are being performed in neonates. These studies have led to new dosing recommendations with particular consideration for neonate body size and maturation. Herein, we highlight the available pharmacokinetic data for commonly used systemic antibiotics in neonates.

Use of Population Pharmacokinetics and Electronic Health Records to Assess Piperacillin-Tazobactam Safety in Infants

BACKGROUND

Piperacillin, in combination with tazobactam, is frequently used in infants for treating nosocomial infections, although safety data in this population are limited. Electronic health record (EHR) data can be used to evaluate drug safety in infants, but measures of drug exposure are lacking.

METHODS

To relate simulated piperacillin exposure with adverse events (AEs) in infants using EHR data, we identified infants discharged from 333 neonatal intensive care units managed by the Pediatrix Medical Group between 1997 and 2012. Using a previously published population pharmacokinetic model in the target population, we simulated piperacillin steady state area under the concentration versus time curve from zero to τ (AUCss,0-τ) and steady state maximal drug concentration (Cmaxss). Next, we used multivariable logistic regression to evaluate the association between simulated AUCss,0-τ and Cmaxss with clinical AEs (seizure and rash) and laboratory AEs controlling for gestational age. The odds ratios (95% confidence intervals) comparing the third versus the first tertiles for AUCss,0-τ and Cmaxss were reported.

RESULTS

We identified 746 infants with a median (interquartile range) gestational age of 30 weeks (26-33) and postnatal age of 11 days (6-25). The median (interquartile range) piperacillin dose was 225 mg/kg/d (176-300). No significant associations were found between simulated piperacillin exposure (AUCss,0-τ and Cmaxss) and clinical and laboratory AEs.

CONCLUSIONS

We found no associations between predicted piperacillin exposures and the occurrence of AEs. This study confirms the feasibility of using population pharmacokinetics and EHR to relate drug exposure with safety.

Cost-effectiveness of ceftolozane/tazobactam plus metronidazole compared with piperacillin/tazobactam as empiric therapy for the treatment of complicated intra-abdominal infections based on the in-vitro surveillance of bacterial isolates in the UK

AIMS

An increase in the prevalence of antimicrobial resistance among gram-negative pathogens has been noted recently. A challenge in empiric treatment of complicated intra-abdominal infection (cIAI) is identifying initial appropriate antibiotic therapy, which is associated with reduced length of stay and mortality compared with inappropriate therapy. The objective of this study was to assess the cost-effectiveness of ceftolozane/tazobactam + metronidazole compared with piperacillin/tazobactam (commonly used in this indication) in the treatment of patients with cIAI in UK hospitals.

METHODS

A decision-analytic Monte Carlo simulation model was used to compare costs (antibiotic and hospitalization costs) and quality-adjusted life years (QALYs) of patients infected with gram-negative cIAI and treated empirically with either ceftolozane/tazobactam + metronidazole or piperacillin/tazobactam. Bacterial isolates were randomly drawn from the Program to Assess Ceftolozane/Tazobactam Susceptibility (PACTS) database, a surveillance database of non-duplicate bacterial isolates collected from patients in the UK infected with gram-negative pathogens. Susceptibility to initial empiric therapy was based on the measured susceptibilities reported in the PACTS database.

RESULTS

Ceftolozane/tazobactam + metronidazole was cost-effective when compared with piperacillin/tazobactam, with an incremental cost-effectiveness ratio (ICER) of £4,350/QALY and 0.36 hospitalization days/patient saved. Costs in the ceftolozane/tazobactam + metronidazole arm were £2,576/patient, compared with £2,168/patient in the piperacillin/tazobactam arm. The ceftolozane/tazobactam + metronidazole arm experienced a greater number of QALYs than the piperacillin/tazobactam arm (14.31/patient vs 14.21/patient, respectively). Ceftolozane/tazobactam + metronidazole remained cost-effective in one-way sensitivity and probabilistic sensitivity analyses.

CONCLUSIONS

Economic models can help to identify the appropriate choice of empiric therapy for the treatment of cIAI. Results indicated that empiric use of ceftolozane/tazobactam + metronidazole is cost-effective vs piperacillin/tazobactam in UK patients with cIAI at risk of resistant infection. This will be valuable to commissioners and clinicians to aid decision-making on the targeting of resources for appropriate antibiotic therapy under the premise of antimicrobial stewardship.

Ceftolozane-Tazobactam for the Treatment of Multidrug-Resistant Pseudomonas aeruginosa Infections: Clinical Effectiveness and Evolution of Resistance

Background

Data on the use of ceftolozane-tazobactam and emergence of ceftolozane-tazobactam resistance during multidrug resistant (MDR)-Pseudomonas aeruginosa infections are limited.

Methods

We performed a retrospective study of 21 patients treated with ceftolozane-tazobactam for MDR-P. aeruginosa infections. Whole genome sequencing and quantitative real-time polymerase chain reaction were performed on longitudinal isolates.

Results

Median age was 58 years; 9 patients (43%) were transplant recipients. Median simplified acute physiology score-II (SAPS-II) was 26. Eighteen (86%) patients were treated for respiratory tract infections; others were treated for bloodstream, complicated intraabdominal infections, or complicated urinary tract infections. Ceftolozane-tazobactam was discontinued in 1 patient (rash). Thirty-day all-cause and attributable mortality rates were 10% (2/21) and 5% (1/21), respectively; corresponding 90-day mortality rates were 48% (10/21) and 19% (4/21). The ceftolozane-tazobactam failure rate was 29% (6/21). SAPS-II score was the sole predictor of failure. Ceftolozane-tazobactam resistance emerged in 3 (14%) patients. Resistance was associated with de novo mutations, rather than acquisition of resistant nosocomial isolates. ampC overexpression and mutations were identified as potential resistance determinants.

Conclusions

In this small study, ceftolozane-tazobactam was successful in treating 71% of patients with MDR-P. aeruginosa infections, most of whom had pneumonia. The emergence of ceftolozane-tazobactam resistance in 3 patients is worrisome and may be mediated in part by AmpC-related mechanisms. More research on treatment responses and resistance during various types of MDR-P. aeruginosa infections is needed to define ceftolozane-tazobactam's place in the armamentarium.

Multicenter Evaluation of Ceftolozane/Tazobactam for Serious Infections Caused by Carbapenem-Resistant Pseudomonas aeruginosa

A multicenter, retrospective study of patients infected with carbapenem-resistant Pseudomonas aeruginosa who were treated with ceftolozane/tazobactam was performed. Among 35 patients, pneumonia was the most common indication and treatment was successful in 26 (74%). Treatment failure was observed in all cases where isolates demonstrated ceftolozane-tazobactam minimum inhibitory concentrations ≥8 μg/mL.

Pharmaceutical Intermediate-Modified Gold Nanoparticles: Against Multidrug-Resistant Bacteria and Wound-Healing Application via an Electrospun Scaffold

Remedying a multidrug-resistant (MDR) bacteria wound infection is a major challenge due to the inability of conventional antibiotics to treat such infections against MDR bacteria. Thus, developing wound dressings for wound care, particularly against MDR bacteria, is in huge demand. Here, we present a strategy in designing wound dressings: we use a small molecule (6-aminopenicillanic acid, APA)-coated gold nanoparticles (AuNPs) to inhibit MDR bacteria. We dope the AuNPs into electrospun fibers of poly(ε-caprolactone) (PCL)/gelatin to yield materials that guard against wound infection by MDR bacteria. We systematically evaluate the bactericidal activity of the AuNPs and wound-healing capability via the electrospun scaffold. APA-modified AuNPs (Au_APA) exhibit remarkable antibacterial activity even when confronted with MDR bacteria. Meanwhile, Au_APA has outstanding biocompatibility. Moreover, an in vivo bacteria-infected wound-healing experiment indicates that it has a striking ability to remedy a MDR bacteria wound infection. This wound scaffold can assist the wound care for bacterial infections.

Ceftolozane-tazobactam for the treatment of ventilator-associated infections by colistin-resistant Pseudomonas aeruginosa

The use of colistin for the treatment of multiresistant bacteria has led to the emergence of colistin-resistant strains of Gram-negative bacilli. Treatment of infections caused by these pan-drug-resistant bacteria is difficult owing to the paucity of effective antibiotics. We report two cases of ventilator-associated respiratory infection caused by pan-drug-resistant, colistin-resistant Pseudomonas aeruginosa that were successfully treated with ceftolozane-tazobactam.

Evaluation of antimicrobial stewardship (AS) for appropriate use of antimicrobial agents

We implemented an antimicrobial stewardship (AS) program whereby pharmacists sought appropriate use of antimicrobial agents in January 2012. At that time, we targeted anti-methicillin-resistant Staphylococcus aureus (MRSA) agents and carbapenems; however, in January 2014, we added tazobactam/piperacillin (TAZ/PIPC). We evaluated outcomes using multilateral analyses. The average one-day dosage of carbapenems increased; however, the duration of administration and number of recipient patients decreased significantly (P < 0.01). Moreover, the percentage of patients receiving meropenem (MEPM), for whom the time above minimal inhibitory concentration (MIC) was 40% or higher increased (P < 0.01). In contrast, patient utilization of TAZ/PIPC increased significantly after targeting of carbapenems as specific antibacterial agents. However, after TAZ/PIPC was targeted as a specific antibacterial agent, the number of TAZ/PIPC administrations decreased significantly (P < 0.01). The duration of hospitalization and mortality rate in patients receiving specific antibacterial agents significantly decreased after implementation of the AS program (P < 0.01). In conclusion, pharmacist's interventions to provide AS and patient follow-up reduced improper use and promoted proper administration of antibacterial agents. Furthermore, AS was effective in improving patient prognoses and suppressing drug-resistant strains, as well as promoting effective treatment.

Increased Time to Initial Antimicrobial Administration Is Associated With Progression to Septic Shock in Severe Sepsis Patients

OBJECTIVES

To determine if time to initial antimicrobial is associated with progression of severe sepsis to septic shock.

DESIGN

Retrospective cohort.

SETTING

Six hundred fifty-six bed urban academic medical center.

PATIENTS

Emergency department patients greater than or equal to 18 years old with severe sepsis and/or septic shock and antimicrobial administration within 24 hours. Patients with shock on presentation were excluded.

INTERVENTIONS

Not available.

MEASUREMENTS AND MAIN RESULTS

We identified 3,929 severe sepsis patients, with overall mortality 12.8%. Nine hundred eighty-four patients (25.0%) progressed to septic shock. The median time to antimicrobial was 3.77 hours (interquartile range = 1.96-6.42) in those who progressed versus 2.76 hours (interquartile range = 1.60-4.82) in those who did not (p < 0.001). Multivariate logistic regression demonstrated that male sex (odds ratio = 1.18; 95% CI, 1.01-1.36), Charlson Comorbidity Index (odds ratio = 1.18; 95% CI, 1.11-1.27), number of infections (odds ratio = 1.05; 95% CI, 1.02-1.08), and time to first antimicrobial (odds ratio = 1.08; 95% CI, 1.06-1.10) were associated with progression. Each hour until initial antimicrobial administration was associated with a 8.0% increase in progression to septic shock. Additionally, time to broad-spectrum antimicrobial was associated with progression (odds ratio = 1.06; 95% CI, 1.05-1.08). Time to initial antimicrobial was also associated with in-hospital mortality (odds ratio = 1.05; 95% CI, 1.03-1.07).

CONCLUSIONS

This study emphasizes the importance of early, broad-spectrum antimicrobial administration in severe sepsis patients admitted through the emergency department, as longer time to initial antimicrobial administration is associated with increased progression of severe sepsis to septic shock and increased mortality.

[New antibiotics - standstill or progress]

The development of resistance to antibiotics has been ignored for a long time. But nowadays, increasing resistance is an important topic. For a decade no new antibiotics had been developed and it is not possible to quickly close this gap of new resistance and no new drugs. This work presents six new antibiotics (ceftaroline, ceftobiprole, solithromycin, tedizolid, ceftolozane/tazobactam, ceftazidime/avibactam). In part, only expert opinions are given due to lack of study results.The two 5th generation cephalosporins ceftaroline and ceftobiprole have beside their equivalent efficacy to ceftriaxone (ceftaroline) and cefipim (ceftobiprole) high activity against MRSA. The fluoroketolide solithromycin should help against macrolide-resistant pathogens and has been shown to be noninferior to the fluorochinolones. The oxazolidinone tedizolid is effective against linezolid-resistant MRSA. The two cephalosporins ceftolozane/tazobactam and ceftazidime/avibactam are not only effective against gram-negative pathogens, but they have a very broad spectrum. Due to the efficacy against extended-spectrum β‑lactamases, they can relieve the selection pressure of the carbapenems. We benefit from all new antibiotics which can take the selection pressure from other often used antibiotics. The increasing number of resistant gram-negative pathogens worldwide is alarming. Thus, focusing on the development of new drugs is extremely important.

General Method to Determine the Flux of Charged Molecules through Nanopores Applied to β-Lactamase Inhibitors and OmpF

A major challenge in the discovery of the new antibiotics against Gram-negative bacteria is to achieve sufficiently fast permeation in order to avoid high doses causing toxic side effects. So far, suitable assays for quantifying the uptake of charged antibiotics into bacteria are lacking. We apply an electrophysiological zero-current assay using concentration gradients of β-lactamase inhibitors combined with single-channel conductance to quantify their flux rates through OmpF. Molecular dynamic simulations provide in addition details on the interactions between the nanopore wall and the charged solutes. In particular, the interaction barrier for three β-lactamase inhibitors is surprisingly as low as 3-5 kcal/mol and only slightly above the diffusion barrier of ions such as chloride. Within our macroscopic constant field model, we determine that at a zero-membrane potential a concentration gradient of 10 μM of avibactam, sulbactam, or tazobactam can create flux rates of roughly 620 molecules/s per OmpF trimer.

A change for the antibacterial treatment policy to decrease carbapenem consumption at a haematopoietic stem cell transplantation centre

After experiencing a high rate of carbapenem-resistant Gram-negative bacilli infections in febrile neutropenic patients, a two-stage intervention was introduced in the haematopoietic stem cell transplantation (HSCT) centre. During the first eight months of 2014, carbapenems remained the first choice for the empirical treatment of febrile neutropenia while the use of piperacillin/tazobactam (TZP) was encouraged in patients with stable clinical condition. When blood cultures were reported as negative and the patient was clinically stable the carbapenem/TZP treatment was stopped regardless of continuous fever and neutrophil count. From October 2014, TZP (with prolonged infusion) with or without amikacin replaced carbapenems as the first line therapy of neutropenic fever except for high-risk patients previously known as colonized or infected with extended spectrum beta-lactamase (ESBL) producing Enterobacteriaceae, who presented with severe sepsis, septic shock or nosocomial pneumonia, and recently transferred from the intensive care unit with a high endemicity of multidrug-resistant Gram-negative bacilli. Vancomycin or teicoplanin was used when there was suspicion of septic shock or detection of severe mucositis and central-line associated bacteraemia. The antibacterial therapy was escalated or de-escalated in culture-positive patients according to the antimicrobial susceptibility reports and clinical progress. Daily defined dosages (DDD) per 1000 patient days were calculated for all antibiotics by the hospital pharmacist for each year. A total of 913 admissions with 11,544 patient-days were followed in 2013; and 1,072 admissions with 11,843 patient-days were followed in 2014. The rate of ESBL production in Enterobacteriaceae bacteraemia was as 31.8% in 2013 and 47.3% in 2014. All staphylococci isolated from blood culture were methicillin-resistant for both years. All Enterococcus faecium isolates but one from blood cultures were resistant to ampicillin. The number of the patients who died during hospitalization was 24 in 2013, and 17 patients died in 2014. The DDDs/1000 patient days for imipenem, meropenem, vancomycin, teicoplanin, daptomycin, linezolid, colistin, piperacillin/tazobactam and amikacin in 2013 and 2014 were respectively as follows; 201 vs 19 (p<0.001); 1,578 vs 1,092 (p<0.001); 533 vs 251 (p<0.001); 205 vs 159 (p<0.001); 56 vs 14 (p<0.001); 76 vs 26 (p<0.001); 188 vs 154 (p<0.001); 157 vs 254 (p<0.001); and 5 vs 41 (p<0.001). Our study showed that a febrile neutropenia pathway guided by local epidemiology and international guidelines can reduce the use of antibiotics in haematological cancer or HSCT patients. The sustainability of such an intervention requires strong multidisciplinary cooperation.

Subcritical water oxidation of 6-aminopenicillanic acid and cloxacillin using H2O2, K2S2O8, and O2

This study was undertaken to investigate the degradation of 6-aminopenicillanic acid (6-APA) and cloxacillin in aqueous solution by the combined effect of subcritical water and the oxidising agents O₂, H₂O₂, and K₂S₂O₈. Nano ZnO was used as a solid catalyst. Response surface methodology was used to determine the optimum experimental parameters (temperature, treatment time, and concentration of oxidising agent). For 6-APA, the maximum organic carbon (TOC) removal rates of 83.54%, 81.11% and 42.42% were obtained using H₂O₂, K₂S₂O₈, and O₂, respectively. For cloxacillin, the maximum TOC removal rates of 67.69%, 76.02% and 14.45% were obtained using H₂O₂, K₂S₂O₈, and O₂, respectively. Additionally, the impact of nano and commercial ZnO on TOC removal rates was determined. Secondary ions produced during the degradation process-such as nitrite, nitrate, sulphate and chloride-were determined using ion chromatography.

Acute kidney injury in patients treated with vancomycin and piperacillin-tazobactam: A retrospective cohort analysis

BACKGROUND

Empiric antimicrobial therapy often consists of the combination of gram-positive coverage with vancomycin (VAN) and gram-negative coverage, specifically an antipseudomonal beta-lactam such as piperacillin-tazobactam (PTZ). Nephrotoxicity is commonly associated with VAN therapy; however, recent reports show higher nephrotoxicity rates among patients treated with the combination of VAN and PTZ.

OBJECTIVE

This study evaluated the effect of the VAN/PTZ combination on acute kidney injury (AKI) compared to VAN and PTZ monotherapies.

DESIGN, SETTING, AND PATIENTS

This is a retrospective cohort analysis of adult patients without renal disease receiving VAN, PTZ, or the combination from September 1, 2010 through August 31, 2014 at an academic medical center.

MEASUREMENTS

The primary outcome was AKI incidence as defined by the Risk, Injury, Failure, Loss, End-stage (RIFLE) criteria.

METHODS

Continuous and categorical variables were assessed with appropriate tests. Univariate and multivariate logistic regressions were performed to assess for associations between variables and AKI incidence. Subanalyses based on severity of illness were performed.

RESULTS

Overall, 11,650 patients were analyzed, with 1647 (14.1%) developing AKI. AKI was significantly more frequent in the VAN/PTZ group (21%) compared to either monotherapy group (VAN 8.3%, PTZ 7.8%, P ⟨ 0.001 for both). Combination therapy was independently associated with higher AKI odds compared to monotherapy with either agent (adjusted odds ratio [aOR], 2.03; 95% confidence interval [CI], 1.74-2.39; aOR, 2.31; 95% CI, 1.97-2.71, for VAN and PTZ, respectively). Receipt of concomitant nephrotoxic drugs was independently associated with increased AKI rates, as were increased duration of therapy, hospital length of stay, increasing severity of illness, and increasing baseline renal function.

CONCLUSIONS

In this study of more than 10,000 patients, VAN combined with PTZ was associated with twice the odds of AKI development compared to either agent as monotherapy. This demonstrates the need for judicious use of combination empiric therapy. Journal of Hospital Medicine 2017;12:77-82.

Clinical Outcomes of Extended Versus Intermittent Infusion of Piperacillin/Tazobactam in Critically Ill Patients: A Prospective Clinical Trial

STUDY OBJECTIVE

To determine whether critically ill patients receiving extended-infusion (EI) piperacillin/tazobactam would have improved clinical outcomes compared with patients receiving intermittent infusions.

DESIGN

Single-center, open-label, prospective study.

SETTING

Twenty-two-bed intensive care unit (ICU) in a regional hospital in Hong Kong.

PATIENTS

A total of 367 adults who had a diagnosis of either bacterial infection or neutropenic fever and had received treatment with piperacillin/tazobactam for at least 48 hours between December 1, 2013, and August 31, 2015.

INTERVENTION

Patients were assigned to receive piperacillin/tazobactam as either a 4-hour EI (182 patients [EI group]) or a 30-minute intermittent infusion (185 patients [non-extended infusion (NEI) group]).

MEASUREMENTS AND MAIN RESULTS

All patients were followed for at least 14 days after treatment assignment. The primary outcome was the 14-day mortality rate after initiation of piperacillin/tazobactam. Secondary outcomes included in-hospital mortality rate, time to defervescence, duration of mechanical ventilatory support, length of ICU stay, and duration of hospital stay. Both groups demonstrated similar 14-day mortality (11.5% in the EI group vs 15.7% in the NEI group, p=0.29). The mean time to defervescence was significantly reduced in the EI group (4 days in the EI group vs 6 days in the NEI group, p=0.01); no significant differences between groups were noted in the other secondary outcomes. An Acute Physiology and Chronic Health Evaluation II score of 29.5 or higher was found to strongly predict 14-day mortality (p=0.03) by Classification and Regression Tree analysis. In the post hoc analyses, a 14-day mortality benefit was demonstrated in patients in the EI group in whom infectious organisms were identified (mortality rate 9.3% in the EI group vs 22.4% in the NEI group, p=0.01) and in whom respiratory tract infection was diagnosed (mortality rate 8.9% in the EI group vs 18.7% in the NEI group, p=0.02).

CONCLUSION

Both the EI and NEI groups demonstrated similar 14-day mortality. Post hoc subgroup analysis revealed a mortality benefit in patients in the EI group who had infectious organisms identified or were diagnosed with respiratory tract infections.

Continuous versus intermittent piperacillin/tazobactam infusion in infection due to or suspected pseudomonas aeruginosa

BACKGROUND

There is lack of information on the efficacy and safety of piperacillin–tazobactam administered by continuous infusion.

OBJECTIVE

The aim of this study was to investigate whether continuous infusion of piperacillin–tazobactam is superior in terms of efficacy to a 30 % higher dose administered by intermittent infusion to treat suspected or confirmed infection due to Pseudomonas aeruginosa. Setting Multicenter clinical trial with 11 third level Spanish hospitals.

METHOD

Randomized, double-blind parallel-group clinical trial, controlled by conventional administration of the drug. Patients randomly assigned in a 1:1 ratio to receive piperacillin–tazobactam as continuous infusion (CI) or intermittent (II).

MAIN OUTCOME MEASURE

Primary efficacy endpoint was percentage of patients having a satisfactory clinical response at completion of treatment, defined as clinical cure or clinical improvement. Adverse events were reported. Results 78 patients were included, 40 in the CI group and 38 in the II group. Mean (standard deviation) duration of treatment was 7 (±4.44) days. 58 patients (74.4 %) experienced cure or improvement at the end of the treatment. There were no statistical differences in cure rates between the two treatment arms and no adverse events were reported.

CONCLUSION

Continuous infusion of piperacillin–tazobactam is an alternative administration drug method at least similar in efficacy and safety to conventional intermittent infusion. Multivariate analysis is needed to determine whether continuous administration might be more beneficial than intermittent in certain patient subgroups.

Serum Piperacillin/Tazobactam Pharmacokinetics in a Morbidly Obese Individual

Objective:

To report pharmacokinetic alterations and optimal dosing of piperacillin/tazobactam in an obese patient.

Case Summary:

A 39-year-old morbidly obese (weight 167 kg, body mass index 50 kg/m2) man was treated with piperacillin/tazobactam 3.375 g every 4 hours for recurrent cellulitis. The wound culture grew Groups A and B Streptococcus and rare Pseudomonas aeruginosa. Blood samples were obtained at steady-state from a peripheral venous catheter at 0, 0.5, 1, 2, 3, and 4 hours after the start of the infusion. Population pharmacokinetics were generated from a previously published data set. The serum concentrations of piperacillin/tazobactam obtained in the patient were compared with the 95% confidence interval from the representative population. Pharmacokinetic parameters such as maximal serum concentration, minimal serum concentration, average steady-state concentration, half-life, elimination rate constant, volume of distribution (Vd), clearance, area under the curve at steady-state, and percent of time greater than the minimum inhibitory concentration (%t>MIC) were calculated and qualitatively compared between the sample and the population.

Discussion:

Substantial differences were noted in both the absolute values at the times of sample collection and the overall concentration-versus-time profile of both compounds. The morbidly obese individual compared with the population demonstrated a reduced average serum steady-state concentration: 39.8 mg/L versus 123.6 mg/L, an increased Vd: 54.3 L versus 12.7 L, and an increased half-life: 1.4 hours versus 0.6 hours, respectively. The %t>MIC of piperacillin for the patient, assuming MICs of 2, 4, 8, 16, 32, 64, and 128 mg/L, was 100%. 100%, 90.9%, 55.4%. 19.9%, 0%, and 0%, respectively.

Conclusions:

Pathogens with elevated MICs may require altered dosing schemes with piperacillin/tazobactam. Future studies are warranted to assess increased dosages, more frequent dosing intervals, or continuous infusion dosing schemes for obese individuals with serious infections.

Using a simple point-prevalence survey to define appropriate antibiotic prescribing in hospitalised children across the UK

BACKGROUND

The National Health Service England, Commissioning for Quality and Innovation for Antimicrobial Resistance (CQUIN AMR) aims to reduce the total antibiotic consumption and the use of certain broad-spectrum antibiotics in secondary care. However, robust baseline antibiotic use data are lacking for hospitalised children. In this study, we aim to describe, compare and explain the prescription patterns of antibiotics within and between paediatric units in the UK and to provide a baseline for antibiotic prescribing for future improvement using CQUIN AMR guidance.

METHODS

We conducted a cross-sectional study using a point prevalence survey (PPS) in 61 paediatric units across the UK. The standardised study protocol from the Antibiotic Resistance and Prescribing in European Children (ARPEC) project was used. All inpatients under 18 years of age present in the participating hospital on the day of the study were included except neonates.

RESULTS

A total of 1247 (40.9%) of 3047 children hospitalised on the day of the PPS were on antibiotics. The proportion of children receiving antibiotics showed a wide variation between both district general and tertiary hospitals, with 36.4% ( 95% CI 33.4% to 39.4%) and 43.0% (95% CI 40.9% to 45.1%) of children prescribed antibiotics, respectively. About a quarter of children on antibiotic therapy received either a medical or surgical prophylaxis with parenteral administration being the main prescribed route for antibiotics (>60% of the prescriptions for both types of hospitals). General paediatrics units were surprisingly high prescribers of critical broad-spectrum antibiotics, that is, carbapenems and piperacillin-tazobactam.

CONCLUSIONS

We provide a robust baseline for antibiotic prescribing in hospitalised children in relation to current national stewardship efforts in the UK. Repeated PPS with further linkage to resistance data needs to be part of the antibiotic stewardship strategy to tackle the issue of suboptimal antibiotic use in hospitalised children.

Population Pharmacokinetics and Safety of Ceftolozane-Tazobactam in Adult Cystic Fibrosis Patients Admitted with Acute Pulmonary Exacerbation

Ceftolozane-tazobactam has potent activity against Pseudomonas aeruginosa, a pathogen associated with cystic fibrosis (CF) acute pulmonary exacerbations (APE). Due to the rapid elimination of many antibiotics, CF patients frequently have altered pharmacokinetics. In this multicenter, open-label study, we described the population pharmacokinetics and safety of ceftolozane-tazobactam at 3 g every 8 h (q8h) in 20 adult CF patients admitted with APE. Population pharmacokinetics were determined using the nonparametric adaptive grid program in Pmetrics for R. A 5,000-patient Monte Carlo simulation was performed to determine the probability of target attainment (PTA) for the ceftolozane component at 1.5 g and 3 g of ceftolozane-tazobactam q8h across a range of MICs using a primary threshold exposure of 60% free time above the MIC (fT>MIC). In these 20 adult CF patients, ceftolozane and tazobactam concentration data were best described by 2-compartment models, and ceftolozane clearance (CL) was significantly correlated with creatinine clearance (r = 0.71, P < 0.001). These data suggest that ceftolozane and tazobactam clearance estimates in CF patients are similar to those in adults without CF (ceftolozane CF CL, 4.76 ± 1.13 liter/h; tazobactam CF CL, 20.51 ± 4.41 liter/h). However, estimates of the volume of the central compartment (Vc) were lower than those for adults without CF (ceftolozane CF Vc, 7.51 ± 2.05 liters; tazobactam CF Vc, 7.85 ± 2.66 liters). Using a threshold of 60% fT>MIC, ceftolozane-tazobactam regimens of 1.5 g and 3 g q8h should achieve PTAs of ≥90% at MICs up to 4 and 8 μg/ml, respectively. Ceftolozane-tazobactam at 3 g q8h was well tolerated. These observations support additional studies of ceftolozane-tazobactam for Pseudomonas aeruginosa APE in CF patients. (This study has been registered at ClinicalTrials.gov under identifier NCT02421120.).

Is high-dose β-lactam therapy associated with excessive drug toxicity in critically ill patients?

BACKGROUND

β-lactam antibiotics may necessitate higher than licensed drug doses to achieve therapeutic exposures in critically ill patients. Therapeutic drug monitoring can be used to guide dosing so as to maximise therapeutic effect whilst reducing the likelihood of exposure-related toxicity.

METHODS

A retrospective review of critically ill patients identified those that received higher than licensed doses of either meropenem (3-6 g/day) or piperacillin-tazobactam (16 g-2 g/day) (i.e. high-dose group) guided by therapeutic drug monitoring. β-lactam-associated toxicities were compared with a patient group of similar age, sex, body mass index and admission diagnosis that received licensed doses of either antibiotic.

RESULTS

Mean daily doses were more than 40% higher in the high-dose groups for each antibiotic. There were no significant differences between the high-dose and licensed-dose groups in terms of hepatocellular derangement (17.9% vs. 31.8%, P=0.25 for meropenem and 17.4% vs. 16.0%, P=0.90 for piperacillin-tazobactam), cholestasis (28.0% vs. 13.6%, P=0.32 for meropenem and 13.0% vs. 4.0%, P=0.26 for piperacillin-tazobactam), need for continuous renal replacement therapy (0% vs. 9.1%, P=0.10 for meropenem and 0% vs. 8.0%, P=0.16 for piperacillin-tazobactam), seizure incidence (7.1% vs. 4.5%, P=0.70 for meropenem and nil for either piperacillin-tazobactam group), thrombocytopenia (9.1% vs. 10.7%, P=0.85 for meropenem and 4.0% vs. 4.3% for piperacillin-tazobactam), or neutropenia (4.5% vs. 3.6%, P=0.95 for meropenem and 0.0% vs. 4.3% for piperacillin-tazobactam).

CONCLUSIONS

Higher than licensed doses of meropenem and piperacillin-tazobactam guided by therapeutic drug monitoring were not associated with additional toxicities. Larger prospective studies are required to confirm the clinical utility of higher than licensed dosing.

Pharmacokinetics and Pharmacodynamics of Extended Infusion Versus Short Infusion Piperacillin-Tazobactam in Critically Ill Patients Undergoing CRRT

BACKGROUND AND OBJECTIVES

Infection is the most common cause of death in severe AKI, but many patients receiving continuous RRT do not reach target antibiotic concentrations in plasma. Extended infusion of β-lactams is associated with improved target attainment in critically ill patients; thus, we hypothesized that extended infusion piperacillin-tazobactam would improve piperacillin target attainment compared with short infusion in patients receiving continuous RRT.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted an institutional review board-approved observational cohort study of piperacillin-tazobactam pharmacokinetics and pharmacodynamics in critically ill patients receiving continuous venovenous hemodialysis and hemodiafiltration at three tertiary care hospitals between 2007 and 2015. Antibiotic concentrations in blood and/or dialysate samples were measured by liquid chromatography, and one- and two-compartment pharmacokinetic models were fitted to the data using nonlinear mixed effects regression. Target attainment for piperacillin was defined as achieving four times the minimum inhibitory concentration of 16 μg/ml for >50% of the dosing cycle. The probabilities of target attainment for a range of doses, frequencies, and infusion durations were estimated using a Monte Carlo simulation method. Target attainment was also examined as a function of patient weight and continuous RRT effluent rate.

RESULTS

Sixty-eight participants had data for analysis. Regardless of infusion duration, 6 g/d piperacillin was associated with ≤45% target attainment, whereas 12 g/d was associated with ≥95% target attainment. For 8 and 9 g/d, target attainment ranged between 68% and 85%. The probability of target attainment was lower at higher effluent rates and patient weights. For all doses, frequencies, patient weights, and continuous RRT effluent rates, extended infusion was associated with higher probability of target attainment compared with short infusion.

CONCLUSIONS

Extended infusions of piperacillin-tazobactam are associated with greater probability of target attainment in patients receiving continuous RRT.

Variability of piperacillin concentrations in relation to tazobactam concentrations in critically ill patients

Therapeutic drug monitoring for critically ill patients receiving piperacillin/tazobactam is described as a useful tool. However, the minimum inhibitory concentration of piperacillin depends on a sufficiently high concentration of tazobactam in case of β-lactamase-producing strains. Therefore, the relationship between piperacillin and tazobactam concentrations was assessed in a heterogeneous group of critically ill patients. Sixty patients with severe infections receiving 4.5 g of piperacillin/tazobactam 2-3 times daily by intermittent infusion were included in this prospective observational study (NCT01793012). Over 4 days, multiple serum samples were obtained to determine the total piperacillin and tazobactam concentrations. The target ranges were defined as trough levels >16 mg/L (>22.5 mg/L) and >4 mg/L (>5.7 mg/L) for the calculated unbound concentrations (measured total concentrations) of piperacillin and tazobactam, respectively. Despite a high correlation coefficient (r = 0.93) comparing piperacillin and tazobactam trough levels, the piperacillin/tazobactam quotients varied between ca. 1 and 10. From linear regression analysis of piperacillin versus tazobactam values, it follows that a piperacillin trough level of 22.5 mg/L might be associated with tazobactam trough levels ranging from 1.5 mg/L to 10.1 mg/L. A 70 mg/L threshold for total piperacillin trough levels would be necessary to ensure that tazobactam concentrations are >5.7 mg/L. Because of the observed variability of piperacillin/tazobactam quotients, defining the total piperacillin target range ≥70 mg/L might be useful to ensure that tazobactam concentrations do not fall below 5.7 mg/L. Further studies are necessary to confirm that the used therapeutic ranges are associated with optimal outcomes in critically ill patients.