Comparison of pharmacokinetics software for therapeutic drug monitoring of piperacillin in patients with severe infections

OBJECTIVE

To evaluate the predictive performance of population pharmacokinetic models for piperacillin (PIP) available in the software MwPharm, TDMx and ID-ODs for initial dosing selection and therapeutic drug monitoring (TDM) purposes.

METHODS

This is a prospective observational study in adult patients with severe infections receiving PIP treatment. Plasma concentrations were quantified by ultra-high performance liquid chromatography coupled to tandem mass spectrometry. The differences between predicted and observed PIP concentrations were evaluated with Bland-Altman plots; additionally, the relative and absolute bias and precision of the models were determined.

RESULTS

A total of 145 PIP plasma concentrations from 42 patients were analysed. For population prediction, MwPharm showed the best predictive performance with a mean relative difference of 34.68% (95% CI -197% to 266%) and a root mean square error (RMSE) of 60.42 µg/mL; meanwhile TDMx and ID-ODs under-predicted PIP concentrations. For individual prediction, the TDMx model was found to be the most precise with a mean relative difference of 7.61% (95% CI -57.63 to 72.86%), and RMSE of 17.86 µg/mL.

CONCLUSION

Current software for TDM is a valuable tool, but it may also include different population pharmacokinetic models in patients with severe infections, and should be evaluated before performing a model-based TDM in clinical practice. Considering the heterogeneous characteristics of patients with severe infections, this study demonstrates the need for therapy personalisation for PIP to improve pharmacokinetic/pharmacodynamic target attainment.

Detection of meningoencephalitis caused by Listeria monocytogenes with ischemic stroke-like onset using metagenomics next-generation sequencing: A case report

RATIONALE

Listeria monocytogenes (L. monocytogenes) is a compatible intracellular bacterial pathogen that can invade different mammalian cells and reach the central nervous system (CNS), leading to meningoencephalitis and brain abscesses. In the diagnosis of L. monocytogenes meningoencephalitis (LMM), conventional tests are often reported as negative due to antibiotic therapy or low bacterial content in cerebrospinal fluid. To date, prompt diagnosis and accurate treatment remain a challenge for patients with Listeria infections.

PATIENT CONCERNS

Here, we report a case of a 64-year-old male diagnosed with LMM by using metagenomics next-generation sequencing (mNGS).

DIAGNOSIS

LMM was confirmed by mNGS analysis of cerebrospinal fluid.

INTERVENTIONS

The patient was treated with piperacillin and sensitive antibiotics.

OUTCOMES

The patient could walk independently about 1 month after admission and was discharged from the hospital.

LESSONS

This case highlights the value of mNGS in the diagnosis of LMM and emphasizes the inadequate sensitivity of conventional diagnostic methods for Listeria infection.

Intramedullary Antibiotic Delivery for Emphysematous Osteomyelitis of the Femur

The authors present a case of bilateral femoral emphysematous osteomyelitis caused by Escherichia coli in a 60-year-old woman with rheumatoid arthritis who was receiving long-term prednisone therapy. The infection in both femoral shafts was eradicated with surgical debridement, followed by insertion of intramedullary rods composed of culture-specific antibiotic cement into the femoral canals in conjunction with 6 weeks of intravenous antibiotics. The rods were subsequently removed, and no signs of further osteomyelitis were recognized at follow-up. To the authors' knowledge, this is the first case of its kind reported in the orthopedic literature. Emphysematous osteomyelitis, a rare and dangerous entity, can be successfully managed by intramedullary antibiotic delivery in the subacute setting. [Orthopedics. 2019; 42(1):e128-e130.].

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.

Efficacy of Collagen Shields after Extracapsular Cataract Extraction

The efficacy of presoaked porcine collagen shields was compared with subconjunctivally injected corticosteroids and antibiotics in reducing ocular inflammation after ECCE with IOL implantation, and signs of reduced oxygen delivery to the cornea were assessed. Fifty eyes of fifty patients were recruited. At the end of surgery 25 eyes (group 1) received a 24-h shield presoaked with 0.1% betamethasone disodium phosphate and 0.5% netilmycin. The other 25 eyes (group 2) received 1 mg betamethasone disodium phosphate and 250 mg piperacillin as a subconjunctival injection. The eyes were then taped closed. Inflammatory parameters (anterior chamber flare, fibrin, folds of Descemet's membrane, corneal edema) and tolerability of the delivery system (pain, itching) were evaluated 24 h after surgery. None of the patients lost the shield and the collagen devices were well tolerated. Groups 1 and 2 showed no significant differences in the parameters considered. There was, however, transient, slight diffuse superficial corneal edema in 24% of group 1 and 4% of group 2, raising the question of inadequate oxygen transmission through collagen shields under closed lids. The results suggest that collagen shields used with the right solution have no significant adverse effect and may be a less invasive alternative to subconjunctival injection.

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.

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.

Tubo-ovarian abscess in non sexually active adolescents

A tubo-ovarian abscess is a rare presentation in non-sexually active adolescents; only 11 cases have been reported in the literature. Variable approaches for diagnosis and management are described. We present a 19-year-old, non-sexually active, medically free girl, who had an abdominopelvic mass with abdominal pain and vomiting followed by fever. She had a confusing presentation of malignancy versus tuberculosis, with the help of imaging, diagnosis and treatment with percutaneous drainage, conservative treatment was achieved. Diagnosis of a tubo-ovarian abscess is difficult in non-sexually active adolescents, a high clinical index of suspicion is important as misdiagnosis may lead to radical and aggressive management, conservative management is possible in many of these patients.

Definition of the Nature and Hapten Threshold of the β-Lactam Antigen Required for T Cell Activation In Vitro and in Patients

Covalent modification of protein by drugs may disrupt self-tolerance, leading to lymphocyte activation. Until now, determination of the threshold required for this process has not been possible. Therefore, we performed quantitative mass spectrometric analyses to define the epitopes formed in tolerant and hypersensitive patients taking the β-lactam antibiotic piperacillin and the threshold required for T cell activation. A hydrolyzed piperacillin hapten was detected on four lysine residues of human serum albumin (HSA) isolated from tolerant patients. The level of modified Lys541 ranged from 2.6 to 4.8%. Analysis of plasma from hypersensitive patients revealed the same pattern and levels of modification 1-10 d after the commencement of therapy. Piperacillin-responsive skin-homing CD4+ clones expressing an array of Vβ receptors were activated in a dose-, time-, and processing-dependent manner; analysis of incubation medium revealed that 2.6% of Lys541 in HSA was modified when T cells were activated. Piperacillin-HSA conjugates that had levels and epitopes identical to those detected in patients were shown to selectively stimulate additional CD4+ clones, which expressed a more restricted Vβ repertoire. To conclude, the levels of piperacillin-HSA modification that activated T cells are equivalent to the ones formed in hypersensitive and tolerant patients, which indicates that threshold levels of drug Ag are formed in all patients. Thus, the propensity to develop hypersensitivity is dependent on other factors, such as the presence of T cells within an individual's repertoire that can be activated with the β-lactam hapten and/or an imbalance in immune regulation.

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.

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.

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.

Pneumocephalus in Child Following Bilateral Otomastoiditis and Nasal Septum Infection

Pneumocephalus is collection of gas or air within the cranial cavity, commonly associated with trauma, cranial surgery, air embolism, open meningomyelocele; and rarely as a result of central nervous system infections. Asymptomatic pneumocephalus usually recovers spontaneously within few days. Untreated pneumocephalus can progress to tension pneumocephalus, manifesting as severe headache, dizziness, cranial nerve palsy, mental changes, seizure and disorientation. Herein, we report a rare case of pneumocephalus in a 9-month infant with subdural effusion following infection of nasal septum and otomastoiditis. There was no sign of meningitis but CThead showed communication of intracranial dura mater across widened foramen caecum with pre-nasal space, and bilateral otomastoiditis with erosion of anterior and lateral wall of right mastoid bone. The patient was treated successfully and discharged without sequelae.

Piperacillin concentration in relation to therapeutic range in critically ill patients--a prospective observational study

BACKGROUND

Piperacillin levels after standard dosing have been shown frequently to be subtherapeutic, especially when renal clearance was augmented. Here, we aimed to determine if piperacillin was in its therapeutic range in a typically heterogeneous intensive care unit patient group, and also to describe target attainment dependent on daily dosage, creatinine clearance, and renal replacement therapy (RRT).

METHODS

Sixty patients with severe infections were included in this monocentric prospective observational study. Patients received 4.5 g of piperacillin-tazobactam two to three times daily by intermittent infusion depending on renal function according to clinical guidelines. Over 4 days, multiple serum samples (median per patient, 29; in total, 1627) were obtained to determine total piperacillin concentrations using ultra-high-performance liquid chromatography/tandem mass spectrometry.

RESULTS

A high heterogeneity of patient characteristics was observed (e.g., on day 1: creatinine clearance 2-233 mL/min and ten patients on RRT). Piperacillin trough levels showed inter-individual variation from 123 to >1785-fold on different study days. Each day, approximately 50% and 60% of the patients had piperacillin levels below the target ranges 1 and 2, respectively [defined for the calculated unbound piperacillin fraction according to the literature as 100% time above MIC (100%fT > MIC) (target range 1) and ≥ 50%fT > 4 × MIC (target range 2); MIC = 16 mg/L]. Whereas only the minority of patients who received piperacillin-tazobactam three times daily (TID) reached target 1 (38% on day 1), most patients who received piperacillin-tazobactam only twice daily (BID) because of severely impaired renal function reached this target (100% on day 1). Patients with RRT had significant higher percentages of fT > MIC. Zero percent, 55% and 100% of patients without RRT who received antibiotics TID reached target 1 when creatinine clearance was > 65 mL/min, 30-65 mL/min and < 30 mL/min, respectively. In patients with causative strains only sensitive to piperacillin-tazobactam of all antibiotics given to the patient, piperacillin levels negatively correlated with CRP concentrations of day 4 (p < 0.05).

CONCLUSIONS

A dosage of 4.5 g piperacillin-tazobactam TID seems to be frequently insufficient in critically ill patients, and also in patients where renal function is mildly to moderately impaired. For these patients, prescription of 4.5 g piperacillin-tazobactam four times daily could be considered.

TRIAL REGISTRATION

Clinicaltrials.gov NCT01793012. Registered 24 January 2013.

Impact of a Dynamic Microbiological Environment on the Clinical Efficacy of Ertapenem and Piperacillin/Tazobactam in the Treatment of Complicated Community-Acquired Intra-Abdominal Infection in Spain: A Cost-Consequence Analysis

BACKGROUND AND OBJECTIVE

The microbial susceptibility of many antibiotics has been affected by prescribing patterns and their extensive use. The purpose of this evaluation was to assess how these changes could affect the initial efficacy of ertapenem and piperacillin/tazobactam in the treatment of complicated intra-abdominal infections (IAIs) acquired in the community and the potential consequences this may have in healthcare costs in Spain.

METHODS

The Initial efficacy of ertapenem and piperacillin/tazobactam for patients with APACHE (Acute Physiology and Chronic Health Evaluation) II scores <10 was extracted from a multicenter randomized study and were combined with the current microbial susceptibilities obtained from the SMART study, a multinational surveillance program. Country-specific pathogens distribution was extracted from a national study in patients with community-acquired IAI. The estimated effectiveness was used in a decision-analytic model to compare total costs between ertapenem and piperacillin/tazobactam in the treatment of complicated IAI. The model performs extensive one-way and probabilistic sensitivity analyses.

RESULTS

The model suggested a savings of €209 (year 2012 values) per patient when complicated IAIs acquired in the community (APACHE II <10) were treated with ertapenem instead of piperacillin/tazobactam. One-way sensitivity analyses showed length of stay as the key driver parameter. Further analysis of this parameter and probabilistic sensitivity analysis confirmed the robustness of our evaluation, with a 58% likelihood of ertapenem being dominant.

CONCLUSIONS

Ertapenem appears to be a cost-saving strategy over piperacillin/tazobactam for the treatment of patients with complicated IAIs acquired in the community in Spain.

Can therapeutic drug monitoring optimize exposure to piperacillin in febrile neutropenic patients with haematological malignancies? A randomized controlled trial

OBJECTIVES

The objectives of this study were to describe piperacillin exposure in febrile neutropenia patients and determine whether therapeutic drug monitoring (TDM) can be used to increase the achievement of pharmacokinetic (PK)/pharmacodynamic (PD) targets.

METHODS

In a prospective randomized controlled study (Australian New Zealand Registry, ACTRN12615000086561), patients were subjected to TDM for 3 consecutive days. Dose was adjusted in the intervention group to achieve a free drug concentration above the MIC for 100% of the dose interval (100% fT>MIC), which was also the primary outcome measure. The secondary PK/PD target was 50% fT>MIC. Duration of fever and days to recovery from neutropenia were recorded.

RESULTS

Thirty-two patients were enrolled. Initially, patients received 4.5 g of piperacillin/tazobactam every 8 h or every 6 h along with gentamicin co-therapy in 30/32 (94%) patients. At the first TDM, 7/32 (22%) patients achieved 100% fT>MIC and 12/32 (38%) patients achieved 50% fT>MIC. Following dose adjustment, 11/16 (69%) of intervention patients versus 3/16 (19%) of control patients (P = 0.012) attained 100% fT>MIC, and 15/16 (94%) of intervention patients versus 5/16 (31%) of control patients (P = 0.001) achieved 50% fT>MIC. After the third TDM, the proportion of patients attaining 100% fT>MIC improved from a baseline 3/16 (19%) to 11/15 (73%) in the intervention group, while it declined from 4/16 (25%) to 1/15 (7%) in the control group. No difference was noted in the duration of fever and days to recovery from neutropenia.

CONCLUSIONS

Conventional doses of piperacillin/tazobactam may not offer adequate piperacillin exposure in febrile neutropenic patients. TDM provides useful feedback of dosing adequacy to guide dose optimization.

Performance of the Baxter Infusor LV10 under hyperbaric conditions

INTRODUCTION

Elastomeric drug delivery devices are a simple way to provide long-term IV therapy to patients in the outpatient setting. Patients receiving hyperbaric oxygen therapy occasionally need these devices. This study compared the performance of the Baxter infusor LV10 elastomeric device in repetitive conditions at pressures of 101.3 kPa and 243 kPa.

METHODS

Ten Baxter infusor LV10 elastomeric devices were pressurised in a hyperbaric chamber to 243 kPa over a two-hour period consistent with a standard medical treatment run. This process was repeated 10 times for each device giving a total of 20 hours under pressure. The fluid delivered by each device was measured and the device weighed at the end of each pressurisation. Ten control devices containing identical drugs were tested in the same manner at 101.3 kPa over the same time period.

RESULTS

No significant differences in output of the devices were observed between hyperbaric and control conditions. The flow rates measured in both study groups were 35% lower than the manufacturer's stated flow rate, possibly due to lower test environment temperature and outdated devices used in the tests.

CONCLUSION

Despite lower than expected flow rates, this study demonstrated no significant difference in the delivery rate of the Baxter infusor LV10 under 243 kPa hyperbaric conditions compared with room pressure.

Severe ovarian hyperstimulation syndrome complicated by Stenotrophomonas maltophilia peritonitis: a case report and literature review

Ovarian hyperstimulation syndrome (OHSS) is an iatrogenic disorder resulting from ovulation induction. Although the occurrence of this disorder is rare, it can be potentially life-threatening in its most severe forms. We herein present the case of a young nulliparous woman who presented with features of abdominal compartment syndrome and was subsequently diagnosed with severe OHSS. All physicians, in particular critical care doctors, must be aware of this rare, but potentially life-threatening iatrogenic disorder.

Extended versus bolus infusion of meropenem and piperacillin: a pharmacokinetic analysis

BACKGROUND

Extended infusion of beta-lactam antibiotics has been advocated as a method for optimizing antibiotic exposure in critically ill patients. The objective of this study was to compare the pharmacokinetics/pharmacodynamics of extended infusion versus bolus infusion of piperacillin and meropenem in critically ill patients with normal renal function.

METHODS

A prospective study of 3 hours extended infusion of meropenem and piperacillin in critically ill patients without renal dysfunction. Results from the extended infusion cohort were compared to previously published bolus infusion data in critically ill patients.

RESULTS

Twenty extended infusion patients (15 piperacillin, 5 meropenem) were compared with 13 bolus infusion patients (8 piperacillin, 5 meropenem). The demographic and clinical characteristics between both groups were not statistically different. Significant pharmacokinetic differences were observed in median (interquartile range) Cmax for both meropenem (extended infusion 17 [12.6-21.9] vs. bolus 85.2 [66.7-140.3]; P=0.01) and piperacillin (extended infusion 76.2 [57.7-92.6] vs. bolus 240.2 [168.5-275.4]; P=0.001). Considerable pharmacokinetic variability existed in each group for both drugs. Compared to bolus infusion, fT>MIC using extended infusion was higher for both drugs: 96% (IQR 71-100%) compared to 77% (IQR 41-93%) for piperacillin (P=0.05) and 82% (IQR 63-89%) compared to 51% (IQR 48-63%) for meropenem (P=0.095); assuming a MIC of 16 mg/L and 2 mg/L respectively.

CONCLUSION

This study confirms that extended infusion in critically ill patients result in advantageous pharmacokinetic profiles by increasing the fT>MIC for piperacillin and meropenem. In a significant subpopulation of critically ill patients with normal renal function, a 100% fT>MIC target is not reached, even with 3-hour extended infusions.

Prophylactic first-line antibiotics reduce infectious fever and shorten hospital stay during chemotherapy-induced agranulocytosis in childhood acute myeloid leukemia

BACKGROUND/AIMS

There exists few pediatric data on the safety and efficacy of prophylactic antibiotics during chemotherapy-induced agranulocytosis.

METHODS

We prospectively studied the incidence of infection-related fever in 38 children, aged 2-16 years, with acute myeloid leukemia (AML) over 121 chemotherapy treatment cycles. A prophylactic group (n = 18) was given either vancomycin/cefepime (400 mg/m(2), q12 h/50 mg/kg, q12 h) or piperacillin/tazobactam (110 mg/kg, q12 h). Control patients (n = 20) received no preventive antibiotics.

RESULTS

The prophylactic group (59 treatment cycles) experienced fever less frequently than the control group (0.4 vs. 0.9 events; p < 0.001), had a longer interval between agranulocytosis and fever (6.4 vs. 3.8 days; p = 0.007), had a shorter duration of hospitalization (21.5 vs. 28.5 days; p < 0.001), and had a lower rate of lung infection (38.8 vs. 80.0%; p < 0.001). One patient taking vancomycin experienced a skin rash and 3 patients taking piperacillin/tazobactam had diarrhea; these side effects subsided after antibiotics were discontinued.

CONCLUSIONS

In children with AML, prophylactic antibiotics during the period of chemotherapy-induced agranulocytosis can effectively reduce the incidence of infectious fever and can shorten the average length of hospital stay, improving treatment success and quality of life.

Susceptibility to antibiotics of aerobic bacteria isolated from community acquired secondary peritonitis in children: therapeutic guidelines might not always fit with and everyday experience

Appendicitis is a frequent clinical condition in normal children that may be complicated by community-acquired secondary peritonitis (CASP). We evaluated the potential efficacy of different drugs for initial treatment of this condition, as recommended by recent Consensus Conference and Guidelines for paediatric patients. Susceptibility to ampicillin-sulbactam, ertapenem, gentamycin, piperacillin, piperacillin-tazobactam, vancomycin, and teicoplanin was evaluated according to EUCST 2012 recommendations in aerobic bacteria isolated from peritoneal fluid in CASP diagnosed from 2005 to 2011 at 'Istituto Giannina Gaslini', Genoa, Italy. A total of 114 strains were analysed: 83 E. coli, 15 P. aeruginosa, 6 Enterococci, and 10 other Gram-negatives. Resistance to ampicillin-sulbactam was detected in 37% of strains, while ertapenem showed a potential resistance of 13% (all P. aeruginosa strains). However, the combination of these drugs with gentamicin would have been increased the efficacy of the treatment to 99 and 100%, respectively. Resistance to piperacillin-tazobactam was 3%, while no strain was resistant to meropenem. Our data suggest that monotherapy with ampicillin-sulbactam or ertapenem for community-acquired secondary peritonitis would present a non-negligible rate of failure, but the addition of gentamycin to these drugs could reset to zero this risk. On the contrary, monotherapy with piperacillin-tazobactam or meropenem is highly effective.

Safety Evaluation of Piperacillin/Tazobactam in Very Low Birth Weight Infants

An open, non-comparative study was designed to evaluate the safety and tolerance of parenteral piperacillin/tazobactam in very low birth weight infants. Twenty-seven patients were included for nosocomial sepsis with gram-negative bacteria (n = 4), nosocomial sepsis not responding to the empirical antibiotic regimen (n = 3), suspected necrotizing enterocolitis (n = 17), and infection after abdominal surgery for reasons other than necrotizing enterocolitis (n = 3). No clinical adverse events considered related to the study drug were noted, in particular, no cases of phlebitis, rash or stool changes. Several possibly related, mild and transitory abnormalities of laboratory parameters were observed. No long-lasting effect on the intestinal flora was detected. Seventeen patients (63%) were considered to have a favorable clinical response. This study demonstrates that piperacillin/tazobactam is a safe and well tolerated drug for preterm infants with bacterial infections, particularly those involving the gastrointestinal tract. Comparative clinical trials are warranted to further clarify the microbiological efficacy of piperacillin/tazobactam in this particular patient population.

Management of Complicated Appendicitis and Comparison of Outcome with Other Primary Sites of Intra-abdominal Infection: Results of a Trial Comparing Ertapenem and Piperacillin-Tazobactam

A post-hoc analysis of data from a trial of complicated intra-abdominal infection was performed to compare the demographic and disease characteristics of patients with complicated appendicitis to those whose primary infection involved other intra-abdominal sites, assess the impact of site of primary infection on outcome, and compare the efficacy and safety of ertapenem 1 g daily with piperacillin-tazobactam 3.375 g every 6 h for treatment of complicated appendicitis. Compared with patients who had primary infection of the colon or another site in the abdomen, patients with complicated appendicitis were younger, had less severe disease (based on lower APACHE II score and lower proportion with generalized peritonitis), and were less likely to be managed by percutaneous drainage of an abscess or to have a postoperative infection. Patients with complicated appendicitis were more likely to have a favorable outcome than were patients with infection of the colon (OR, 3.02; 95% CI, [1.54-5.901; P = .001). At the test-of-cure assessment, 109/123 (88.6%) microbiologically evaluable patients with complicated appendicitis who received ertapenem and 102/113 (90.3%) who received piperacillin-tazobactam had a favorable combined clinical and microbiologic outcome. The frequency and severity of drug-related adverse events were similar in the two treatment groups.

Influence of Renal Function on the Pharmacokinetics of Piperacillin/Tazobactam in Intensive Care Unit Patients During Continuous Venovenous Hemofiltration

The pharmacokinetics of piperacillin/tazobactam (4 g/0.5 g every 6 or 8 hours, by 20-minute intravenous infusion) were studied in 14 patients with acute renal failure who underwent continuous venovenous hemofiltration with AN69 membranes. Patients were grouped according to severity (CL(CR) < or =10 mL/min, 10 < CL(CR) < or =50 mL/min, and CL(CR) > 50 mL/min). A noncompartmental analysis was performed. The sieving coefficient (0.78 +/- 0.28) was similar to the unbound fraction (0.65 +/- 0.24) for tazobactam, but it was significantly different (0.34 +/- 0.25) from the unbound fraction (0.78 +/- 0.14) for piperacillin. Extracorporeal clearance was 37.0% +/- 28.8%, 12.7% +/- 12.6%, and 2.8% +/- 3.2% for piperacillin in each group and 62.5% +/- 44.9%, 35.4% +/- 17.0%, and 13.1% +/- 8.0% for tazobactam. No patients presented tazobactam accumulation. In patients with CL(CR) < 50 mL/min, t(%)ss >MIC90 values were 100% for a panel of 19 pathogens, but in those with CL(CR) > 50 mL/min, t(%)ss >MIC90 indexes were 55.5% and 16.6% for pathogens with MIC90 values of 32 and 64. The extracorporeal clearance of piperacillin/tazobactam is clinically significant in patients with CL(CR) > 50 mL/min, in which the risk of underdosing and clinical failure is important and extra doses are required.

Efficacy and safety of IV/PO moxifloxacin and IV piperacillin/tazobactam followed by PO amoxicillin/clavulanic acid in the treatment of diabetic foot infections: results of the RELIEF study

OBJECTIVE

The aim was to compare the efficacy and safety of two antibiotic regimens in patients with diabetic foot infections (DFIs).

METHODS

Data of a subset of patients enrolled in the RELIEF trial with DFIs requiring surgery and antibiotics were evaluated retrospectively. DFI was diagnosed on the basis of the modified Wagner, University of Texas, and PEDIS classification systems. Patients were randomized to receive either intravenous/oral moxifloxacin (MXF, N = 110) 400 mg q.d. or intravenous piperacillin/tazobactam 4.0/0.5 g t.d.s. followed by oral amoxicillin/clavulanate 875/125 mg b.d. (PIP/TAZ-AMC, N = 96), for 7-21 days until the end of treatment (EOT). The primary endpoint was clinical cure rates in the per-protocol (PP) population at the test-of-cure visit (TOC, 14-28 days after EOT).

RESULTS

There were no significant differences between the demographic characteristics of PP patients in either treatment group. At TOC, MXF and PIP/TAZ-AMC had similar efficacy in both the PP and intent-to-treat (ITT) populations: MXF: 76.4 % versus PIP/TAZ-AMC: 78.1 %; 95 % confidence interval (CI) -14.5 %, 9.0 % in the PP population; MXF: 69.9 % versus PIP/TAZ-AMC: 69.1 %; 95 % CI -12.4 %, 12.1 % in the ITT population. The overall bacteriological success rates were similar in both treatment groups (MXF: 71.7 % versus PIP/TAZ-AMC: 71.8 %; 95 % CI -16.9 %, 10.7 %). A similar proportion of patients (ITT population) experienced any adverse events in both treatment groups (MXF: 30.9 % versus PIP/TAZ-AMC: 31.8 %, respectively). Death occurred in three MXF-treated patients and one PIP/TAZ-AMC-treated patient; these were unrelated to the study drugs.

CONCLUSION

Moxifloxacin has shown favorable safety and efficacy profiles in DFI patients and could be an alternative antibiotic therapy in the management of DFI.

CLINICAL TRIAL

NCT00402727.

Continuous infusion of piperacillin/tazobactam in septic critically ill patients--a multicenter propensity matched analysis

The clinical efficacy of continuous infusion of piperacillin/tazobactam in critically ill patients with microbiologically documented infections is currently unknown. We conducted a retrospective multicenter cohort study in 7 Portuguese intensive care units (ICU). We included 569 critically ill adult patients with a documented infection and treated with piperacillin/tazobactam admitted to one of the participating ICU between 2006 and 2010. We successfully matched 173 pairs of patients according to whether they received continuous or conventional intermittent dosing of piperacillin/tazobactam, using a propensity score to adjust for confounding variables. The majority of patients received 16g/day of piperacillin plus 2g/day of tazobactam. The 28-day mortality rate was 28.3% in both groups (p = 1.0). The ICU and in-hospital mortality were also similar either in those receiving continuous infusion or intermittent dosing (23.7% vs. 20.2%, p = 0.512 and 41.6% vs. 40.5%, p = 0.913, respectively). In the subgroup of patients with a Simplified Acute Physiology Score (SAPS) II>42, the 28-day mortality rate was lower in the continuous infusion group (31.4% vs. 35.2%) although not reaching significance (p = 0.66). We concluded that the clinical efficacy of piperacillin/tazobactam in this heterogeneous group of critically ill patients infected with susceptible bacteria was independent of its mode of administration, either continuous infusion or intermittent dosing.

[Microbiological characteristics of pathogens causing bacteremia among hospitalized pediatric oncology patients with fever and neutropenia]

BACKGROUND

Bacterial infections are a major threat to pediatric oncology patients with fever and neutropenia. Current management consists of empiric broad-spectrum antibiotics and prompt medical evaluation. Local bacterial susceptibility rates were published in 2005, and the local protocol (piperacillin and amikacin) was established as an adequate empiric treatment with -100% efficiency against the common pathogens in our pediatric hemato-oncology ward.

AIM

To characterize the spectrum of bacteria isolated from blood cultures at the pediatric hemato-oncology ward between 2008- 2010, and to evaluate the current protocol.

METHODS

A prospective study, conducted in the pediatric hemato-oncologic ward among hospitalized children (2 months - 18 years) with fever and neutropenia. Blood cultures from peripheral blood and central lines were obtained from all patients at admission. Bacterial resistance to various antimicrobial agents was determined.

RESULTS

During 2008-2010, 195 admissions (105 children) due to fever and neutropenia were recorded. Approximately 30% of all blood cultures were positive for a pathogen with -50% Gram positive bacteria mostly CONS. The most prevalent Gram negative bacteria were acinetobacter and klebsiella spp. Candida species were isolated from 7% of positive cultures. Susceptibility rates for the current empiric antimicrobial regimen were about 90%. CONS bacteremia rate increased from 4% in 2000-2002 to 29% in 2008-2010 (p < 0.01).

CONCLUSIONS

The currently applied empiric antimicrobial protocol is an optimal first line regimen, considering the susceptibility of the most common pathogens. Judicious use of carbapenems for gram negative bacteria and glycopeptides or other novel antimicrobial agents in cases of CONS bacteremia is required.

A 9-Year retrospective review of antibiotic cycling in a surgical intensive care unit

BACKGROUND

Six years after initiating a monthly antibiotic cycling protocol in the surgical intensive care unit (SICU), we retrospectively reviewed antibiogram-derived sensitivities of predominant gram-negative pathogens before and after antibiotic cycling. We also examined susceptibility patterns in the medical intensive care unit (MICU) where antibiotic cycling is not practiced.

MATERIALS AND METHODS

Antibiotic cycling protocol was implemented in the SICU starting in 2003, with monthly rotation of piperacillin/tazobactam, imipenem/cilastin, and ceftazidime. SICU antibiogram data from positive clinical cultures for years 2000 and 2002 were included in the pre-cycling period, and those from 2004 to 2009 in the cycling period.

RESULTS

Profiles of SICU pseudomonal isolates before (n = 116) and after (n = 205) implementing antibiotic cycling showed statistically significant improvements in susceptibility to ceftazidime (66% versus 81%; P = 0.003) and piperacillin/tazobactam (75% versus 85%; P = 0.021), while susceptibility to imipenem remained unaltered (70% in each case; P = 0.989). Susceptibility of E. coli isolates to piperacillin/tazobactam improved significantly (46% versus 83%; P < 0.0005), trend analysis showing this improvement to persist over the study period (P = 0.025). Similar findings were not observed in the MICU. Review of 2004-2009 antibiotic prescription practices showed monthly heterogeneity in the SICU, and a 2-fold higher prescribing of piperacillin/tazobactam in the MICU (P < 0.0001).

CONCLUSIONS

Six years into antibiotic cycling, we found either steady or improved susceptibilities of clinically relevant gram-negative organisms in the SICU. How much of this effect is from cycling is unknown, but the antibiotic heterogeneity provided by this practice justifies its ongoing use.

[Efficacy and safety of piperacillin-tazobactam for febrile neutropenic patients in Japan]

The IDSA guideline for management of febrile neutropenic patients updated in 2010 recommends monotherapy with anti-pseudomonal-lactam agents, including piperacillin-tazobactam (PIPC/TAZ) for high-risk patients. However, clinical studies of PIPC/TAZ are limited in Japanese patients. In this study, we conducted an open-labeled non-randomized prospective trial to examine the efficacy and safety of PIPC/TAZ as an empirical treatment for Japanese patients with febrile neutropenia. Forty-nine febrile episodes in neutropenic patients excluding those undergoing allogeneic stem cell transplantation (high risk 36, low risk 13) were analyzed. The overall response rate was 71%, and no significant differences between the high-risk and the low-risk group were observed (high risk 72%, low risk 69%). Neither PS nor usage of G-CSF affected the response rate. No major side effects were observed in the study. The efficacy and the safety profile of PIPC/TAZ treatment were comparable to those in other previous Western studies. In conclusion, this study suggests PIPC/TAZ is effective and well tolerated as an initial empirical treatment for febrile neutropenic Japanese patients.

Treating pneumonia in critical care in the United Kingdom following failure of initial antibiotic: a cost-utility analysis comparing meropenem with piperacillin/tazobactam

BACKGROUND

Treating patients admitted to critical care with severe pneumonia requires timely intervention with an effective antibiotic. This reduces the risk of dying of pneumonia and minimises complications associated with a prolonged stay in critical care.

OBJECTIVE

To compare the cost-effectiveness of meropenem 1 g/8 h with piperacillin/tazobactam 4.5 g/8 h for treating pneumonia in UK critical care.

METHODS

A Markov model was built to estimate lifetime costs and quality-adjusted life years (QALYs) of using meropenem versus piperacillin/tazobactam to treat severe pneumonia. Estimates of effectiveness, utility weights and costs were obtained from published sources. Probabilistic sensitivity analysis was conducted to address uncertainty in the model results.

RESULTS

Cost of treating a patient with severe pneumonia was estimated as £19,026 with meropenem and £19,978 with piperacillin/tazobactam, respectively. QALYs gained were 4.768 with meropenem and 4.654 with piperacillin/tazobactam. Probabilistic sensitivity analysis showed meropenem to be consistently less costly and more effective than piperacillin/tazobactam.

CONCLUSION

The additional efficacy of meropenem translates into more patients surviving critical care and leaving this high-cost service more quickly than if they had been treated with piperacillin/tazobactam. As meropenem is more effective and less expensive than piperacillin/tazobactam at treating patients with severe pneumonia, it is the dominant treatment option.

[Effect of excipients on the preparation and properties of antibiotic solution for intravenous application]

OBJECTIVE

To evaluate the effect of excipients disodium-edetate dihydrate and citric acid monohydrate on rate of antibiotic powder dissolution, particle size after dissolution and chemical stability of the product after reconstitution with water for injection and 5% glucose solution.

MATERIAL AND METHODS

The product containing excipients (Tazocin) was compared with generic products without excipients. Rate of dissolution was evaluated organoleptically and spectrophotometrically, particle size was determined microscopically after reconstitution and after 4 hours of standing at laboratory temperature and chemical stability was assessed by HPLC.

RESULTS

Tazocin dissolved significantly faster in both solvents compared to products without excipients (3-4 min versus 10-13 min). The limit for maximal number of particles larger than 25 mm in the reconstituted solution was not exceeded in any of the products either after using water for injection or after using 5% glucose, both after reconstitution and after 4 hours of standing at laboratory temperature. Nevertheless, only for Tazocin the number of unwanted larger particles decreased in time in both solvents. Disodium-edetate dihydrate and citric acid stabilized the dissolved particles of the active substance and prevented its transformation into the insoluble form, which results in lower number of unwanted large particles. Tazocin was more stable, but the stability was not significantly better than its generic products.

CONCLUSIONS

Disodium-edetate dihydrate and citric acid monohydrate (and possibly the used method of lyophilisation) therefore have a positive effect on the preparation and properties of antibiotic solution for intravenous application.

Distinct synergistic action of piperacillin and methylglyoxal against Pseudomonas aeruginosa

The dicarbonyl compound methylglyoxal is a natural constituent of Manuka honey produced from Manuka flowers in New Zealand. It is known to possess both anticancer and antibacterial activity. Such observations prompted to investigate the ability of methylglyoxal as a potent drug against multidrug resistant Pseudomonas aeruginosa. A total of 12 test P. aeruginosa strains isolated from various hospitals were tested for their resistances against many antibiotics, most of which are applied in the treatment of P. aeruginosa infections. Results revealed that the strains were resistant to many drugs at high levels, only piperacillin, carbenicillin, amikacin and ciprofloxacin showed resistances at comparatively lower levels. Following multiple experimentations it was observed that methylglyoxal was also antimicrobic against all the strains at comparable levels. Distinct and statistically significant synergism was observed between methylglyoxal and piperacillin by disc diffusion tests when compared with their individual effects. The fractional inhibitory concentration index of this combination evaluated by checkerboard analysis, was 0.5, which confirmed synergism between the pair. Synergism was also noted when methylglyoxal was combined with carbenicillin and amikacin.

Low-dose beta-lactam plus amikacin in febrile neutropenia: cefepime vs. piperacillin/tazobactam, a randomized trial

Patients with fever and granulocytopenia are at risk of developing severe infection. We performed a prospective, randomized trial to evaluate the efficacy of low-dose cefepime plus amikacin (C-A) compared to low-dose piperacillin/tazobactam plus amikacin (PT-A). Patients received cefepime (2 g/12 h) plus amikacin (15 mg/kg/day) or piperacillin/tazobactam (4 g/500 mg/8 h) plus amikacin. A total of 317 episodes of febrile granulocytopenia in 190 patients were studied (152 in the C-A group, 165 in the PT-A group). A microbiologically documented infection was present in 53 (35%) episodes in the C-A group and 41 (25%) episodes in the PT-A group (p = ns); a clinically documented infection was observed in 39 (26%) and 47 (28%) episodes, respectively. Toxicity was observed in 6 (4%) episodes in the C-A group and in 5 (3%) episodes in the PT-A group. The antibiotic success rate (no change or addition of antibiotics) was recorded in 89 (59%) and 105 (64%) cases, respectively (p = ns). Mortality related to infection was similar in each arm (3.9% vs. 3.6%). Combination therapy of low-dose beta-lactam with an aminoglycoside achieves very good response rates and low rates of toxicity. It might be an attractive option in an environment of increasing resistance among gram-negative bacteria.

Use of the lymphocyte transformation test in the diagnosis of DRESS syndrome induced by ceftriaxone and piperacillin-tazobactam: two case reports

Drug-related rash with eosinophilia and systemic symptoms (DRESS) syndrome, or drug-induced hypersensitivity syndrome (DIHS), is a life-threatening multiorgan systemic reaction characterized by rash, fever, lymphadenopathy, hepatitis, and leukocytosis with eosinophilia. Aromatic anticonvulsant drugs and allopurinol have been reported to be the most frequent eliciting agents. Our search of the literature revealed only 2 cases induced by piperacillin and 1 case by ceftriaxone.We present 2 cases of DRESS syndrome induced by the beta-lactam drugs ceftriaxone and piperacillin-tazobactam. An allergological workup including skin prick test, intradermal tests, patch tests, and lymphocyte transformation test (LTT) was performed. LTT was shown to be a useful technique in both cases to help to identify the drugs involved.