Relationship between structure and convulsant properties of some beta-lactam antibiotics following intracerebroventricular microinjection in rats

Cefepime-Induced Encephalopathy in Patients Treated for Urinary Tract Infection

Cefepime is a fourth-generation cephalosporin antibiotic administered intravenously used to treat various bacterial infections, including urinary tract infections. Administering cefepime to patients should be done with caution, understanding both potential risks and side effects. A 74-year-old female presented to the family medicine clinic with abdominal pain and a history of urinary tract infections. The workup included a CT scan that showed bowel obstruction and bladder wall thickening. Due to a history of urinary tract infections, three days following the presentation, the patient underwent an explorative laparotomy. Following the laparotomy, the patient was started on cefepime, a fourth-generation cephalosporin antibiotic. Five days following the initial presentation, the patient became confused and was nonverbal. An encephalopathy workup showed a negative MRI, but an EEG was consistent with encephalopathy. Cefepime was discontinued. Forty-eight hours after cefepime was discontinued, the patient returned to baseline with normal cognitive function. It is crucial that clinicians understand the different classifications of antibiotics, as well as the drugs and potential side effects of prescriptions. Cefepime can be used in gram-negative infections with resistance to more generic antibiotics. It has the ability to cross the blood-brain barrier, making it effective in treating meningitis. It has also been shown to cause encephalopathy as a side effect. It is important that clinicians understand the different generations of cephalosporins, as well as the cross-reactions and potential side effects of prescriptions. These factors must be considered when prescribing broad-spectrum antibiotics, such as cefepime.

Antibiotic-induced neurological adverse drug reactions

Antibiotics are drugs widely used all around the world. Central nervous system adverse drug reactions (CNS ADRs) are mostly under-suspected with antibiotics. Nevertheless, these ADRs could lead to severe complications such as encephalopathy. To illustrate the clinical patterns of these off-target ADRs, we here present data from pharmacovigilance system, through different populations and points of view (worldwide, French population, vulnerable population and individual). These data could help clinicians to better know about CNS ADRs with antibiotics, to better identify risk factors and vulnerable patients and to highlight the importance to set up the right diagnostic explorations in the best timing to avoid complications. Clinicians should request a pharmacological opinion from pharmacologist (biologists and pharmacovigilance clinicians) in front of vulnerable population before or during antibiotics. Pharmacovigilance advice could help clinicians in the diagnosis and the management of an ADR. Therapeutic drug monitoring is particularly contributive to adjust doses of antibiotics administered in vulnerable patients. Pharmacovigilance advice and TDM are essential to perform personalized medicine, and contribute to the proper use of drugs.

Ceftriaxone-induced encephalopathy in a patient with a normal renal function

Ceftriaxone-induced encephalopathy is an exceptionally rare adverse effect of this commonly used cephalosporin and is generally observed in patients undergoing haemodialysis or suffering from severe renal failure. We present a case of a fit woman in her mid-80s with a normal renal function who developed severe fluctuating neurological symptoms (aphasia, loss of contact, chorea-like tongue movements) while being treated with ceftriaxone for a urinary tract infection with bacteraemia. The symptoms began on day 4 of treatment and an adverse drug reaction was suspected on day 7, after exhaustive investigations failed to reveal another cause. A complete recovery was observed 3 days after discontinuing ceftriaxone. Our case highlights the need to consider the diagnosis of ceftriaxone encephalopathy, even if the traditional risk factors are lacking. In this article, we also provide a brief overview of the pathophysiology as well as a literature review concerning the subject.

New Antibiotics for the Treatment of Nosocomial Central Nervous System Infections

Nosocomial central nervous system (CNS) infections with carbapenem- and colistin-resistant Gram-negative and vancomycin-resistant Gram-positive bacteria are an increasing therapeutic challenge. Here, we review pharmacokinetic and pharmacodynamic data and clinical experiences with new antibiotics administered intravenously for the treatment of CNS infections by multi-resistant bacteria. Cefiderocol, a new siderophore extended-spectrum cephalosporin, pharmacokinetically behaves similar to established cephalosporins and at high doses will probably be a valuable addition in our therapeutic armamentarium for CNS infections. The new glycopeptides dalbavancin, telavancin, and oritavancin are highly bound to plasma proteins. Although effective in animal models of meningitis, it is unlikely that they reach effective cerebrospinal fluid (CSF) concentrations after intravenous administration alone. The β-lactam/β-lactamase inhibitor combinations have the principal problem that both compounds must achieve adequate CSF concentrations. In the commercially available combinations, the dose of the β-lactamase inhibitor tends to be too low to achieve adequate CSF concentrations. The oxazolidinone tedizolid has a broader spectrum but a less suitable pharmacokinetic profile than linezolid. The halogenated tetracycline eravacycline does not reach CSF concentrations sufficient to treat colistin-resistant Gram-negative bacteria with usual intravenous dosing. Generally, treatment of CNS infections should be intravenous, whenever possible, to avoid adverse effects of intraventricular therapy (IVT). An additional IVT can overcome the limited penetration of many new antibiotics into CSF. It should be considered for patients in which the CNS infection responds poorly to systemic antimicrobial therapy alone.

Amoxicillin-Induced Neurotoxicity: Contribution of a Healthcare Data Warehouse to the Determination of a Toxic Concentration Threshold

Background: Amoxicillin (AMX)-induced neurotoxicity is well described and may be associated with AMX overexposure. No neurotoxic concentration threshold has been determined thus far. A better knowledge of maximum tolerable AMX concentrations is of importance to improve the safety of high doses of AMX. Methods: We conducted a retrospective study using the local hospital data warehouse EhOP® to generate a specific query related to AMX neurotoxicity symptomatology. All patient medical reports containing a mention of neurotoxicity clinical symptoms coupled with AMX plasma concentration measurements were explored. Patients were classified into two groups according to the imputability of AMX in the onset of their neurotoxicity, on the basis of chronological and semiological criteria. A receiver-operating characteristic curve was performed to identify an AMX neurotoxic steady-state concentration (Css) threshold. Results: The query identified 101 patients among 2054 patients benefiting from AMX TDM. Patients received a median daily dose of 9 g AMX, with a median creatinine clearance of 51 mL/min. A total of 17 of the 101 patients exhibited neurotoxicity attributed to AMX. The mean Css was higher for patients with neurotoxicity attributed to AMX (118 ± 62 mg/L) than those without 74 ± 48 mg/L (p = 0.002). A threshold AMX concentration of 109.7 mg/L predicted the occurrence of neurotoxicity. Conclusions: This study identified, for the first time, an AMX Css threshold of 109.7 mg/L associated with an excess risk of neurotoxicity. This approach needs to be confirmed by a prospective study with systematic neurological evaluation and TDM.

The Blood-Brain Barrier and Pharmacokinetic/Pharmacodynamic Optimization of Antibiotics for the Treatment of Central Nervous System Infections in Adults

Bacterial central nervous system (CNS) infections are serious and carry significant morbidity and mortality. They encompass many syndromes, the most common being meningitis, which may occur spontaneously or as a consequence of neurosurgical procedures. Many classes of antimicrobials are in clinical use for therapy of CNS infections, some with established roles and indications, others with experimental reporting based on case studies or small series. This review delves into the specifics of the commonly utilized antibacterial agents, updating their therapeutic use in CNS infections from the pharmacokinetic and pharmacodynamic perspectives, with a focus on the optimization of dosing and route of administration that have been described to achieve good clinical outcomes. We also provide a concise synopsis regarding the most focused, clinically relevant information as pertains to each class and subclass of antimicrobial therapeutics. CNS infection morbidity and mortality remain high, and aggressive management is critical in ensuring favorable patient outcomes while averting toxicity and upholding patient safety.

Responses to antibiotics in human iPSC-derived neurons based on the clinical antibiotic-associated encephalopathy classification

Antibiotic-associated encephalopathy (AAE) is a central nervous system disorder caused by antibiotics administration and classified into three types based on clinical symptoms. Type 1 AAE causes seizures and myoclonus, type 2 causes psychiatric symptoms, and type 3 is characterized by cerebellar ataxia. In this study, we investigated whether the electrical activity of in vitro human iPSC-derived neurons to antibiotics could be classified based on the 3 types of AAEs classified by clinical symptoms. Glutamatergic, GABAergic neurons and astrocytes differentiated from human iPS cells were seeded on micro-electrode array (MEA). The cumulative administration of 13 different antimicrobials detected changes in neural activity that differed according to AAE type. Next, we classified the antimicrobials by principal component analysis (PCA) and confirmed the AAE type of each agent. We found that Types 1-3 AAE agents were distributed separately. The classification of antibiotics depending on electrophysiological response characteristics was consistent with the clinical practice classification of AAEs. In conclusion, the combination of electrophysiological responses of human iPS cell-derived neural networks measured by MEA plus multivariate analysis methods will effectively detect and classify antibiotics developmental risks.

Application of a Physiologically Based Pharmacokinetic Model to Predict Cefazolin and Cefuroxime Disposition in Obese Pregnant Women Undergoing Caesarean Section

Intravenous (IV) cefuroxime and cefazolin are used prophylactically in caesarean sections (CS). Currently, there are concerns regarding sub-optimal dosing in obese pregnant women compared to lean pregnant women prior to CS. The current study used a physiologically based pharmacokinetic (PBPK) approach to predict cefazolin and cefuroxime pharmacokinetics in obese pregnant women at the time of CS as well as the duration that these drug concentrations remain above a target concentration (2, 4 or 8 µg/mL or µg/g) in plasma or adipose tissue. Cefazolin and cefuroxime PBPK models were first built using clinical data in lean and in obese non–pregnant populations. Models were then used to predict cefazolin and cefuroxime pharmacokinetics data in lean and obese pregnant populations. Both cefazolin and cefuroxime models sufficiently described their total and free levels in the plasma and in the adipose interstitial fluid (ISF) in non–pregnant and pregnant populations. The obese pregnant cefazolin model predicted adipose exposure adequately at different reference time points and indicated that an IV dose of 2000 mg can maintain unbound plasma and adipose ISF concentration above 8 µg/mL for 3.5 h post dose. Predictions indicated that an IV 1500 mg cefuroxime dose can achieve unbound plasma and unbound ISF cefuroxime concentration of ≥8 µg/mL up to 2 h post dose in obese pregnant women. Re-dosing should be considered if CS was not completed within 2 h post cefuroxime administration for both lean or obese pregnant if cefuroxime concentrations of ≥8 µg/mL is required. A clinical study to measure cefuroxime adipose concentration in pregnant and obese pregnant women is warranted.

Encephalopathy induced by high levels of ceftriaxone in the blood and cerebrospinal fluid

Ceftriaxone is commonly used to treat bacterial infections. Encephalopathy is a rare adverse effect of ceftriaxone therapy, and most cases have been diagnosed based on medical history. We report a case of a 73-year-old woman with ceftriaxone-associated encephalopathy, which was confirmed by measuring the ceftriaxone levels in the blood and cerebrospinal fluid. She regularly underwent hemodialysis. She received intravenous ceftriaxone at a dose of 1 g/day for 4 days for enteritis, and mental status began to be disturbed during the therapy. Six days after ceftriaxone discontinuation, her consciousness level rapidly improved. Thus, ceftriaxone-associated encephalopathy was suspected. High ceftriaxone levels in the blood and cerebrospinal fluid were observed while the patient had disturbed consciousness. This case indicated that high ceftriaxone levels in the blood and cerebrospinal fluid were related to development of encephalopathy. The estimation of ceftriaxone levels may be useful for an accurate diagnosis.

Cefepime-Induced Encephalopathy in a High-Risk Patient With Renal Insufficiency and Cirrhosis

Cefepime is a fourth-generation, cephalosporin antibiotic commonly used as a first-line empirical treatment in a wide range of bacterial infections. It is predominantly excreted renally; therefore, a reduction in kidney function allows for the accumulation of cefepime to potentially toxic levels. Here we present a case of cefepime-induced encephalopathy (CIE) in a 67 years old male patient with advanced-stage renal insufficiency and cirrhosis who was admitted to our hospital for altered mental status (AMS). The patient was initially treated for hepatic encephalopathy (HE) given an elevated ammonia level (105 µg/dL), which had significantly improved. He was also placed on intravenous (IV) cefepime for Pseudomonas bacteremia. Four days later, the patient became drowsy and confused. A detailed workup for secondary causes of AMS was performed however no significant acute abnormalities were detected. The ammonia level remained within the normal range. There was no acute intracranial pathology reported on a head computerized tomography (CT). Furthermore, an electroencephalograph (EEG) was obtained which showed generalized periodic discharge with a tri-phasic wave pattern suggesting non-convulsive status epilepticus (NCSE). CIE was suspected at that point and cefepime administration was stopped. Following cefepime discontinuation, there was a remarkable improvement in the patient’s mental status for several days after cefepime discontinuation that supported the diagnosis of CIE in our patient.

Although the exact pathophysiology is unclear, CIE should be suspected in elderly patients, patients with renal dysfunction, and critical illness. Meanwhile, liver dysfunction can be an additional risk factor for CIE as it increases the permeability of the blood-brain barrier (BBB), altered neurotransmission, and neuro-inflammation.

Status and Safety Signals of Cephalosporins in Children: A Spontaneous Reporting Database Study

Introduction: Cephalosporins are widely used in clinical treatment of children, but it is difficult to carry out clinical trials and there is no strong evidence of their safety. Therefore, adverse drug reactions (ADR) of cephalosporins can be a public health problem that deserves attention. Methods: ADR reports collected by the Hubei Adverse Drug Reaction Monitoring Center from 2014 to 2019 were analysed. The safety of Cephalosporins was described by descriptive analysis and three signal mining methods, including the reporting odd ratio (ROR), proportional reporting ratio (PRR), and comprehensive standard method (MHRA). Results: The findings indicated that the age groups of 0-1 and 2-3 years had the highest rates of reporting ADRs. Children aged 0-4 years reported more ADRs, while the proportion of severe ADRs was lower than the average (6.63%). Among the 37 cephalosporins, the severe ADRs of ceftezole, ceftazidime, cefoperazone/sulbactam, cefotaxime, ceftriaxone were reported more and the proportion of severe ADRs was higher. The proportion of severe ADRs of most cephalosporin compound preparations was higher than that of corresponding single components. A total of 99.18% of the cases improved after treatment. There were four deaths whose ADRs were mainly anaphylactic shock, dyspnoea, and anaphylactoid reaction. In signal mining, the three methods produced 206 signals that were the same, and 73 of them were off-label ADRs. Conclusion: ADRs were common but not serious in children aged 0-4 years. And the reported rate of serious ADRs in children aged over 4 years increased with age. ADR reports of ceftezole, ceftazidime, cefoperazone/sulbactam, cefotaxime, ceftriaxone were numerous and serious, and the safety of cephalosporin compound preparations in children was doubtful. Ceftezole may cause off-label ADRs including tremor, face oedema, cyanosis, pallor, rigors, and palpitation. The labeling of ADRs in children in cephalosporin instructions and the record of allergic history need to be improved.

Beta-Lactams Dosing in Critically Ill Patients with Gram-Negative Bacterial Infections: A PK/PD Approach

Beta-lactam antibiotics are often the backbone of treatment for Gram-negative infections in the critically ill. Beta-lactams exhibit time-dependent killing, and their efficacy depends on the percentage of dosing interval that the concentration remains above the minimum inhibitory concentration. The Gram-negative resistance rates of pathogens are increasing in the intensive care unit (ICU), and critically ill patients often possess physiology that makes dosing more challenging. The volume of distribution is usually increased, and drug clearance is variable. Augmented renal clearance and hypermetabolic states increase the clearance of beta-lactams, while acute kidney injury reduces the clearance. To overcome the factors affecting ICU patients and decreasing susceptibilities, dosing strategies involving higher doses, and extended or continuous infusions may be required. In this review, we specifically examined pharmacokinetic models in ICU patients, to determine the desired beta-lactam regimens for clinical breakpoints of Enterobacterales and Pseudomonas aeruginosa, as determined by the European Committee on Antimicrobial Susceptibility Testing. The beta-lactams evaluated included penicillins, cephalosporins, carbapenems, and monobactams. We found that when treating less-susceptible pathogens, especially P. aeruginosa, continuous infusions are frequently needed to achieve the desired pharmacokinetic/pharmacodynamic targets. More studies are needed to determine optimal dosing strategies in the novel beta-lactams.

Beta-Lactams Toxicity in the Intensive Care Unit: An Underestimated Collateral Damage?

Beta-lactams are the most commonly prescribed antimicrobials in intensive care unit (ICU) settings and remain one of the safest antimicrobials prescribed. However, the misdiagnosis of beta-lactam-related adverse events may alter ICU patient management and impact clinical outcomes. To describe the clinical manifestations, risk factors and beta-lactam-induced neurological and renal adverse effects in the ICU setting, we performed a comprehensive literature review via an electronic search on PubMed up to April 2021 to provide updated clinical data. Beta-lactam neurotoxicity occurs in 10-15% of ICU patients and may be responsible for a large panel of clinical manifestations, ranging from confusion, encephalopathy and hallucinations to myoclonus, convulsions and non-convulsive status epilepticus. Renal impairment, underlying brain abnormalities and advanced age have been recognized as the main risk factors for neurotoxicity. In ICU patients, trough concentrations above 22 mg/L for cefepime, 64 mg/L for meropenem, 125 mg/L for flucloxacillin and 360 mg/L for piperacillin (used without tazobactam) are associated with neurotoxicity in 50% of patients. Even though renal complications (especially severe complications, such as acute interstitial nephritis, renal damage associated with drug induced hemolytic anemia and renal obstruction by crystallization) remain rare, there is compelling evidence of increased nephrotoxicity using well-known nephrotoxic drugs such as vancomycin combined with beta-lactams. Treatment mainly relies on the discontinuation of the offending drug but in the near future, antimicrobial optimal dosing regimens should be defined, not only based on pharmacokinetics/pharmacodynamic (PK/PD) targets associated with clinical and microbiological efficacy, but also on PK/toxicodynamic targets. The use of dosing software may help to achieve these goals.

Unmasking antibiotic-associated neurological disorders: The underminer in Intensive Care Unit

Psychosis is a common and intractable disorder of hospitalization, especially in patients hospitalized in Intensive Care Unit (ICU). Along with the widely use of multiple antibiotics in community-acquired infection and hospital-acquired infection, the occurrence of antibiotic-associated neurological disorders has become more frequently. However, antibiotic neurotoxicity is often overlooked or misinterpreted. In this review, we summarized the neurological disorders caused by antibacterial agent usage and firstly systematically formulated the pathogenesis of antibiotic-associated neurotoxic reactions. Precautions of the complications are critical in preventing serious clinical outcome as the inducement is curable. Regular neurological physical examination, electroencephalogram (EEG) examination, lumbar puncture and therapeutic drug monitoring closely are essential for early diagnosis and differential diagnosis.

Antibiotic-induced epileptic seizures: mechanisms of action and clinical considerations

In recent years, there has been growing interest in the development of epileptic seizures as an adverse effect of antibiotic therapy. The most commonly accepted mechanisms underlying the development of antibiotic-induced seizures include direct- and indirect gamma-aminobutyric acid (GABA) antagonism, inhibition of GABA synthesis, and glutaminergic N-methyl-D-Aspartate (NMDA) receptor agonistic activity. Inhibitory pathway inhibition leads to increased neuronal excitability and lowered seizure threshold. Blockage of myoneural presynaptic acetylcholine release, mitochondrial dysfunction, interference of neural protein synthesis, and oxidative stress caused by the generation of neurotoxic radicals also contributes to the development of neurotoxicity. Patients with pre-existing risk factors such as renal or hepatic insufficiency, central nervous system pathology, neurological diseases, history of epilepsy or seizures, critical illness, and increased age are more susceptible to seizure development as a consequence of antibiotic therapy. Administration of antibiotics, together with antiseizure drugs, may also lead to enhanced seizure risk due to drug interactions, which predisposes to alterations in drug metabolism and therapeutic efficacy.

Tolerability of high-dose ceftriaxone in CNS infections: a prospective multicentre cohort study

BACKGROUND

Ceftriaxone is widely used to treat community-acquired CNS bacterial infections. French guidelines for meningitis in adults promote 75-100 mg/kg/day ceftriaxone without an upper limit for dosage, yet little is known about the pharmacology and tolerability of such regimens.

PATIENTS AND METHODS

A multicentre prospective cohort study was conducted in adult patients to assess the adverse drug reactions (ADRs) of high-dose ceftriaxone (i.e. daily dosage ≥4 g or ≥75 mg/kg) in CNS infections and to analyse their related factors. Drug causality was systematically assessed by an expert committee who reviewed the medical charts of all included patients.

RESULTS

A total of 196 patients were enrolled over a 31 month period. Median dosage and duration of ceftriaxone were 96.4 mg/kg/day (7 g/day) and 8 days, respectively. Nineteen ceftriaxone-related ADRs (mainly neurological) occurred in 17 patients (8.7%), with only one case of treatment discontinuation (biliary pseudolithiasis). In univariate analysis, older age, male gender, renal impairment and high trough ceftriaxone plasma concentration were associated with ceftriaxone-related ADRs.

CONCLUSIONS

High-dose ceftriaxone for CNS infection administered as recommended by French guidelines in adults was well tolerated overall, suggesting these recommendations could be applied and generalized. In patients with advanced age or renal insufficiency, prescription should be done with caution and therapeutic drug monitoring could be useful.

Intrathecal Antibacterial and Antifungal Therapies

Intrathecal administration of anti-infectives is indicated in central nervous system infections by multiresistant pathogens when drugs that can reach adequate cerebrospinal fluid (CSF) concentrations by systemic therapy are not available. Antibiotics that readily pass the blood-brain and blood-CSF barriers and/or that have low toxicity allowing an increase in the daily dosage should not be used for intrathecal therapy. Intrathecal therapy is accompanied by systemic treatment. Antibacterials indispensable for intrathecal therapy include aminoglycosides, colistin, daptomycin, tigecycline, and vancomycin. Limited experience suggests the utility of the antifungals amphotericin B and caspofungin. Intraventricular administration ensures distribution throughout the CSF compartment, whereas intralumbar dosing often fails to attain adequate antibiotic concentrations in the ventricles. The individual dose is determined by the estimated size of the CSF space and by the estimated clearance from CSF. For moderately lipophilic anti-infectives with a molecular weight above approximately 1,000 g/mol, as well as for hydrophilic drugs with a molecular weight above approximately 400 g/mol, one daily dose is normally adequate. The ventricular drain should be clamped for 15 to 120 min to facilitate the distribution of the anti-infective in the CSF space. Therapeutic drug monitoring of the trough levels is necessary only in cases of therapeutic failure.

Cristiano ML, Rijo P, Pombeiro AJL. In Vitro Assessment of Antimicrobial, Antioxidant, and Cytotoxic Properties of Saccharin-Tetrazolyl and -Thiadiazolyl Derivatives: The Simple Dependence of the pH Value on Antimicrobial Activity

The antimicrobial, antioxidant, and cytotoxic activities of a series of saccharin-tetrazolyl and -thiadiazolyl analogs were examined. The assessment of the antimicrobial properties of the referred-to molecules was completed through an evaluation of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values against Gram-positive and Gram-negative bacteria and yeasts. Scrutiny of the MIC and MBC values of the compounds at pH 4.0, 7.0, and 9.0 against four Gram-positive strains revealed high values for both the MIC and MBC at pH 4.0 (ranging from 0.98 to 125 µg/mL) and moderate values at pH 7.0 and 9.0, exposing strong antimicrobial activities in an acidic medium. An antioxidant activity analysis of the molecules was performed by using the DPPH (2,2-diphenyl-1-picrylhydrazyl) method, which showed high activity for the TSMT (N-(1-methyl-2H-tetrazol-5-yl)-N-(1,1-dioxo-1,2-benzisothiazol-3-yl) amine, 7) derivative (90.29% compared to a butylated hydroxytoluene positive control of 61.96%). Besides, the general toxicity of the saccharin analogs was evaluated in an Artemia salina model, which displayed insignificant toxicity values. In turn, upon an assessment of cell viability, all of the compounds were found to be nontoxic in range concentrations of 0-100 µg/mL in H7PX glioma cells. The tested molecules have inspiring antimicrobial and antioxidant properties that represent potential core structures in the design of new drugs for the treatment of infectious diseases.

Encephalopathy Induced by High Plasma and Cerebrospinal Fluid Ceftriaxone Concentrations in a Hemodialysis Patient

Encephalopathy is a rare side effect of cephalosporin treatment. We herein present a case of encephalopathy induced by ceftriaxone, a third-generation cephalosporin, in a patient with renal failure. An 86-year-old woman on maintenance hemodialysis received ceftriaxone for Helicobacter cinaedi bacteremia. Her mental status deteriorated during antibiotic treatment, and an electroencephalogram revealed triphasic waves predominantly in the frontal area. Her consciousness improved after the discontinuation of the antibiotic due to the suspicion of ceftriaxone-induced encephalopathy. This is the first reported case of encephalopathy associated with high plasma and cerebrospinal fluid ceftriaxone concentrations, and provides significant evidence for a causal relationship between the administration of ceftriaxone and the onset of encephalopathy.

A Treatable Encephalopathy in a Peritoneal Dialysis Patient - Cefepime-Induced Encephalopathy

We report a patient with end-stage renal disease on peritoneal dialysis, who developed encephalopathy after receiving a few doses of cefepime. He recovered clinically and electroencephalographically after having discontinued the culprit agent and undergone hemodialysis. This case highlights the importance of promptly recognizing this reversible encephalopathy, which can lead to the avoidance of unnecessary workup, reduce the length of hospital stay, and thereby improve the patients’ outcome.

Optimization of the treatment with beta-lactam antibiotics in critically ill patients-guidelines from the French Society of Pharmacology and Therapeutics (Société Française de Pharmacologie et Thérapeutique-SFPT) and the French Society of Anaesthesia and Intensive Care Medicine (Société Française d'Anesthésie et Réanimation-SFAR)

BACKGROUND

Beta-lactam antibiotics (βLA) are the most commonly used antibiotics in the intensive care unit (ICU). ICU patients present many pathophysiological features that cause pharmacokinetic (PK) and pharmacodynamic (PD) specificities, leading to the risk of underdosage. The French Society of Pharmacology and Therapeutics (SFPT) and the French Society of Anaesthesia and Intensive Care Medicine (SFAR) have joined forces to provide guidelines on the optimization of beta-lactam treatment in ICU patients.

METHODS

A consensus committee of 18 experts from the two societies had the mission of producing these guidelines. The entire process was conducted independently of any industry funding. A list of questions formulated according to the PICO model (Population, Intervention, Comparison, and Outcomes) was drawn-up by the experts. Then, two bibliographic experts analysed the literature published since January 2000 using predefined keywords according to PRISMA recommendations. The quality of the data identified from the literature was assessed using the GRADE® methodology. Due to the lack of powerful studies having used mortality as main judgement criteria, it was decided, before drafting the recommendations, to formulate only "optional" recommendations.

RESULTS

After two rounds of rating and one amendment, a strong agreement was reached by the SFPT-SFAR guideline panel for 21 optional recommendations and a recapitulative algorithm for care covering four areas: (i) pharmacokinetic variability, (ii) PK-PD relationship, (iii) administration modalities, and (iv) therapeutic drug monitoring (TDM). The most important recommendations regarding βLA administration in ICU patients concerned (i) the consideration of the many sources of PK variability in this population; (ii) the definition of free plasma concentration between four and eight times the Minimal Inhibitory Concentration (MIC) of the causative bacteria for 100% of the dosing interval as PK-PD target to maximize bacteriological and clinical responses; (iii) the use of continuous or prolonged administration of βLA in the most severe patients, in case of high MIC bacteria and in case of lower respiratory tract infection to improve clinical cure; and (iv) the use of TDM to improve PK-PD target achievement.

CONCLUSIONS

The experts strongly suggest the use of personalized dosing, continuous or prolonged infusion and therapeutic drug monitoring when administering βLA in critically ill patients.

Neurological Adverse Effects Attributable to β-Lactam Antibiotics: A Literature Review

β-lactam antibiotics are commonly prescribed antibiotic drugs. To describe the clinical characteristics, risk markers and outcomes of β-lactam antibiotic-induced neurological adverse effects, we performed a general literature review to provide updated clinical data about the most used β-lactam antibiotics. For selected drugs in each class available in France (ticarcillin, piperacillin, temocillin, ceftazidime, cefepime, cefpirome, ceftaroline, ceftobiprole, ceftolozane, ertapenem and aztreonam), a systematic literature review was performed up to April 2016 via an electronic search on PubMed. Articles that reported original data, written in French, Spanish, Portuguese or English, with available individual data for patients with neurological symptoms (such as seizure, disturbed vigilance, confusional state, myoclonia, localising signs, and/or hallucinations) after the introduction of a β-lactam antibiotic were included. The neurological adverse effects of piperacillin and ertapenem are often described as seizures and hallucinations (>50 and 25% of cases, respectively). Antibiotic treatment is often adapted to renal function (>70%), and underlying brain abnormalities are seen in one in four to one in three cases. By contrast, the neurological adverse drug reactions of ceftazidime and cefepime often include abnormal movements but few hallucinations and seizures. These reactions are associated with renal insufficiency (>80%) and doses are rarely adapted to renal function. Otherwise, it appears that monobactams do not have serious neurological adverse drug reactions and that valproic acid and carbapenem combinations should be avoided. The onset of disturbed vigilance, myoclonus, and/or seizure in a patient taking β-lactam antibiotics, especially if associated with renal insufficiency or underlying brain abnormalities, should lead physicians to suspect adverse drug reactions and to consider changes in antibacterial therapy.

Meropenem and Vaborbactam: Stepping up the Battle against Carbapenem-resistant Enterobacteriaceae

Vaborbactam (VAB; formerly RPX7009) is a novel beta-lactamase inhibitor based on a cyclic boronic acid pharmacophore with potent inhibitory activity against Ambler class A and C beta-lactamases. It has been co-formulated with meropenem to restore its activity against Klebsiella pneumoniae carbapenemases (KPC). VAB does not inhibit class B or D carbapenemases, nor does it improve the activity of meropenem against multidrug-resistant nonfermenting gram-negative bacilli, notably Acinetobacter spp. and Pseudomonas aeruginosa. The purpose of this article is to review existing data pertaining to the biochemistry, mechanism of action, pharmacokinetics/pharmacodynamics, in vitro activity, and current progress in clinical trials of meropenem and VAB (MV). Phase 1 studies have demonstrated single and multiple doses of VAB up to 2000 mg, alone or in combination with meropenem 2000 mg administered as a prolonged infusion over 3 hours, are well tolerated with an adverse effect profile similar to that of meropenem monotherapy. The available data suggest preexisting resistance among KPC-producing isolates is rare. Strains with elevated MICs have been characterized by multiple resistance determinants including porin defects, increased drug efflux, and increased blaKPC expression. It remains uncertain whether multifactorial resistance will emerge during MV treatment and with more widespread use. Early data are positive for complicated urinary tract infections and MV compared with best available therapy in patients with serious carbapenem-resistant Enterobacteriaciae (CRE) infections. As clinicians contemplate how to incorporate MV into CRE treatment strategies, it will be important to track and understand resistance, discern the role, if any, of combination therapy in enhancing efficacy and/or preserving activity, and define the specific therapeutic niche of MV among the expanding anti-CRE armamentarium.

Cefepime-Induced Neurotoxicity Despite Dose Adjustment for Renal Disease: A Brief Report and Review of the Literature

Cefepime is increasingly used as empiric treatment for fever in the setting of neutropenia. We present a patient with acute-on-chronic renal disease who received cefepime at the appropriate dose for his glomerular filtration rate but developed cefepime-associated encephalopathy. Here, we review neurologic toxicities of cefepime and present suggestions for work-up and management.

Genetically epilepsy-prone rats (GEPRs) and DBA/2 mice: Two animal models of audiogenic reflex epilepsy for the evaluation of new generation AEDs

This review summarizes the current knowledge about DBA/2 mice and genetically epilepsy-prone rats (GEPRs) and discusses the contribution of such animal models on the investigation of possible new therapeutic targets and new anticonvulsant compounds for the treatment of epilepsy. Also, possible chemical or physical agents acting as proconvulsant agents are described. Abnormal activities of enzymes involved in catecholamine and serotonin synthesis and metabolism were reported in these models, and as a result of all these abnormalities, seizure susceptibility in both animals is greatly affected by pharmacological manipulations of the brain levels of monoamines and, prevalently, serotonin. In addition, both genetic epileptic models permit the evaluation of pharmacodynamic and pharmacokinetic interactions among several drugs measuring plasma and/or brain level of each compound. Audiogenic models of epilepsy have been used not only for reflex epilepsy studies, but also as animal models of epileptogenesis. The seizure predisposition (epileptiform response to sound stimulation) and substantial characterization of behavioral, cellular, and molecular alterations in both acute and chronic (kindling) protocols potentiate the usefulness of these models in elucidating ictogenesis, epileptogenesis, and their mechanisms. This article is part of a Special Issue entitled "Genetic and Reflex Epilepsies, Audiogenic Seizures and Strains: From Experimental Models to the Clinic".

Complications associated with antibiotic administration: neurological adverse events and interference with antiepileptic drugs

Antibiotic use is associated with toxic effects involving the peripheral and central nervous systems and it may interfere with antiepileptic drugs, causing significant variations in their serum levels and activity. Prompt identification of neurological complications during antibiotic therapy is important in order to make appropriate modifications to medication. Characteristics of the drug and the patient, including age and underlying diseases, may favour these complications. The main aim of this study was to review the neurological adverse events that may follow antibiotic administration, the mechanisms that cause them, and the possibility of prevention and treatment. Moreover, the interference of antibiotics with serum levels and the activity of antiepileptic drugs are discussed. The results demonstrate that antibiotic-associated adverse events involving the nervous system are relatively uncommon and are only rarely severe and irreversible, although neurotoxicity has been reported for several antibiotics. Moreover, for patients receiving antiepileptic drugs, monitoring of drug serum levels to avoid the risk of toxicity or inadequate therapy is mandatory during antibiotic treatment. Areas for future research include the effects of combined antibiotic therapies as well as multiple antiepileptic drugs in study populations with an adequate sample size, including neonates and infants, patients with pharmacoresistant epilepsy and elderly patients.

Cefepime-Induced Non-Convulsive Status Epilepticus in a Patient with Normal Renal Function

Cefepime-induced encephalopathy including nonconvulsive status epilepticus has been known to develop in the patients with renal impairment. However, we report a 74-year-old woman with normal renal function who developed stuporous mental status during cefepime administration. Electroencephalogram (EEG) revealed 2 Hz rhythmic sharp-and-waves continuously, which suggested nonconvulsive status epilepticus (NCSE). After cefepime discontinuation, clinical symptoms recovered gradually and EEG findings showed only background slowing without epileptiform discharges. Cefepime-induced NCSE could be developed even in the patients with normal renal function, when they are elderly. Therefore, clinicians should be aware of the possibility of cefepime-induced NCSE when prescribing cefepime even to the patients with normal renal function.

A comparative study between heterogeneous stannous chloride loaded silica nanoparticles and a homogeneous stannous chloride catalyst in the synthesis of 5-substituted 1H-tetrazole

Heterogeneous SnCl₂–nano-SiO₂efficiently catalyzed 5-substituted 1H-tetrazole synthesis with excellent yield. It is widely applicable on aliphatic, aromatic, heteroaromatic and sterically hindered nitriles with five times recyclability. ​

A DFT study of the ionization and electron attachment of 2-azido pyridine

A DFT study using B3LYP/6-31G(d,p) level of theory is pursued to investigate the energy and geometry changes of 2-azido pyridine isomers in the S0, D0(+), and D0(-). In S0, cis-2 azidopyridine is the most stable, followed by cyclic tetrazole and trans isomer is the least stable. In D0(+), the cis isomer is the most stable, followed by trans isomer, and tetrazole isomer is the least stable. In the D0(-) state, the trans form is the most stable, followed by the cis and the tetrazolo form is the least stable. Single point vertical excitation energy calculations of the cis form gave four excited states at 266.4, 239.4, 199.4, and 196.1nm, all having π-π(∗) character. For trans isomer, five excited states at, 256.7, 250.3, 229.7, 199.0, 197.0nm all resulting from π-π(∗) transitions. For the tetrazole isomer, seven excited states at 269.3, 242.7, 198.0, 187.2, 183.9, 182.1, 178.7nm all resulting from π-π(∗) transitions. The geometries of the 3 isomers show noticeable changes in bond lengths, bond angles and dihedral angles, upon ionization and electron attachment. The ionization results in a remarkable variation of the NBO atomic charges as a result of ionization and electron attachment. where electron density of HOMO of the D0(+) state is found to be much lower than that of the HOMO of the S0 in the case of ionization. The dipole moment calculations show that tetrazole isomer has the largest polarization in the S0 state, followed by cis isomer and trans isomer is the least polarized. The same pattern is found in the D0(+) state. In the D0(-) state, trans isomer is the highest polarized, followed by the cis, and tetrazole isomer is the least polarized. The rotational constants calculations of cis- isomer show that the cation is elongated along the long in-plane axis and compressed along the two short out-of-plane axes while the anion is compressed along the long in-plane axis, and elongated along the two short out-of plane axes. The cation and anion of trans isomer show similar behavior to the cis isomer. The cation of cyclic tetrazole, is compressed along the long in-plane axis and elongated along the two short out-of-plane axes, while the anion elongates along the 3 mutually perpendicular axes.

Cloxacillin-induced seizure in a hemodialysis patient

We are reporting a cloxacillin-induced seizure in a patient with stage 5 chronic kidney disease requiring hemodialysis. To our knowledge, there are no published case reports of seizures induced by parenteral cloxacillin in hemodialysis patients. A young hemodialysis female was admitted to the hospital with decreased level of consciousness. Blood cultures revealed methicillin-sensitive Staphylococcus aureus where cloxacillin 2 g intravenously every 4 hours was initiated. Head computed tomography (CT) was not significant. After 14 hours of cloxacillin therapy (4 doses), the patient demonstrated tonic/clonic seizure activity, where phenytoin and lorazepam were initiated. The anti-seizure medications partially reduced seizure activity. Once the cloxacillin was discontinued, the seizures stopped. Two weeks later, all anti-seizure medications were stopped with no further seizure activity. Cloxacillin elimination in hemodialysis patients is similar to patients with normal kidney function. Although cloxacillin does not significantly cross the blood-brain barrier, the correlation between the start of seizures and cloxacillin initiation was confirmed by the negative CT and blood chemistry laboratory results. Moreover, seizure activity was terminated upon discontinuation of cloxacillin. Although further investigation for the cause of such seizures is warranted, clinicians should use caution when giving high doses of cloxacillin in hemodialysis patients.

Synthetic application of gold nanoparticles and auric chloride for the synthesis of 5-substituted 1H-tetrazoles

An effective one-pot, convenient gold catalyzed synthesis of 5-substituted 1H-tetrazoles has been discussed.

Ceftriaxone-induced acute encephalopathy in a peritoneal dialysis patient

Encephalopathy is a rare side effect of third and fourth generation cephalosporins. Renal failure and preexisting neurological disease are notable risk factors. Recognition is important as discontinuing the offending agent usually resolves symptoms. We present a case of acute encephalopathy in a patient with end stage renal disease (ESRD) treated with peritoneal dialysis (PD) who received intravenous ceftriaxone for peritonitis. This case illustrates the potential severe neurologic effects of cephalosporins, which are recommended by international guidelines as first-line antimicrobial therapy for spontaneous bacterial peritonitis.