A case report of treatment of a streptococcal brain abscess with ceftobiprole supported by the measurement of drug levels in the cerebrospinal fluid

In this paper, we describe the case of a patient admitted to our hospital because of a brain abscess due to Streptococcus intermedius. The management of brain abscess is challenging given the limited potential drug options with effective penetration into both the central nervous system and the abscess capsule to achieve adequate therapeutic concentrations. Due to the high anti-streptococcal activity of ceftobiprole and the availability of ceftobiprole therapeutic drug monitoring in our hospital, we decided to treat the patient with ceftobiprole. To maximize the antimicrobial effect of ceftobiprole, we chose a prolonged intravenous infusion, and we monitored its concentrations in both plasma and cerebrospinal fluid.

An Aminoglycoside-Sparing Regimen with Double Beta-Lactam to Successfully Treat Granulicatella adiacens Prosthetic Aortic Valve Endocarditis-Time to Change Paradigm?

(1) Background: Granulicatella adiacens is a former nutritionally variant streptococci (NVS). NVS infective endocarditis (IE) is generally characterized by a higher rate of morbidity and mortality, partially due to difficulties in choosing the most adequate microbiological culture method and the most effective treatment strategy, and partially due to higher rates of complications, such as heart failure, peripheral septic embolism, and peri-valvular abscess, as well as a higher rate of valve replacement. Depending on the affected valve (native valve endocarditisNVE, or prosthetic valve endocarditisPVE), the American Heart Association (AHA) 2015 treatment guidelines (GLs) suggest penicillin G, ampicillin, or ceftriaxone plus gentamicin (2 weeks for NVE and up to 6 weeks for PVE), while vancomycin alone may be a reasonable alternative in patients who are intolerant of β-lactam therapy. The European Society of Cardiology (ESC) 2023 GLs recommend treating NVE with penicillin G, ceftriaxone, or vancomycin for 6 weeks, suggesting combined with an aminoglycoside (AG) for at least the first 2 weeks only for PVE; likewise, the same recommendations for IE due to Enterococcus faecalis. (2) Methods: Starting from the case of a 51-year-old man with G. adiacens aortic bio-prosthesis IE who was successfully treated with aortic valve replacement combined with double beta-lactams, an AG-sparing regimen, we performed microbiology tests in order to validate this potential treatment change. (3) Results: As for E. faecalis IE, we found that the combination of ampicillin plus cephalosporines (like ceftriaxone or ceftobiprole) showed a synergistic effect in vitro, probably due to wider binding to penicillin-binding proteins (PBPs), thus contributing to enhanced bacterial killing and good clinical outcome, as well as avoiding the risk of nephrotoxicity due to AG association therapy. (4) Conclusions: Further studies are required to confirm this hypothesis, but double beta-lactams and an adequate sourcecontrol could be a choice in treating G. adiacens IE.

Population Pharmacokinetic and Pharmacodynamic Analysis of Valganciclovir for Optimizing Preemptive Therapy of Cytomegalovirus Infections in Kidney Transplant Recipients

This study aimed to develop a population pharmacokinetic/pharmacodynamic (PK/PD) model of valganciclovir for preemptive therapy of cytomegalovirus (CMV) infection in kidney transplant patients. A population PK/PD model was developed with Monolix. Ganciclovir concentrations and CMV viral loads were obtained retrospectively from kidney transplant patients receiving routine clinical care. Ten thousand Monte Carlo simulations were performed with the licensed dosages adjusted for renal function to assess the probability of attaining a viral load target of ≤290 and ≤137 IU/mL. Fifty-seven patients provided 343 ganciclovir concentrations and 328 CMV viral loads for PK/PD modeling. A one-compartment pharmacokinetic model coupled with an indirect viral turnover growth model with stimulation of viral degradation pharmacodynamic model was devised. Simulations showed that 1- and 2-log10 reduction of CMV viral load mostly occurred between a median of 5 to 6 and 12 to 16 days, respectively. The licensed dosages achieved a probability of reaching the viral load target ≥90% at days 35 to 49 and 42 to 56 for the thresholds of ≤290 and ≤137 IU/mL, respectively. Simulations indicate that in patients with an estimated glomerular filtration rate of 10 to 24 mL/min/1.73m2, a dose increase to 450 mg every 36 h may reduce time to optimal viral load target to days 42 and 49 from a previous time of 49 and 56 days for the thresholds of ≤290 and ≤137 IU/mL, respectively. Currently licensed dosages of valganciclovir for preemptive therapy of CMV infection may achieve a viral load reduction within the first 2 weeks, but treatment should continue for ≥35 days to ensure viral load suppression.

Linezolid Population Pharmacokinetics to Improve Dosing in Cardiosurgical Patients: Factoring a New Drug-Drug Interaction Pathway

Background

Linezolid-induced myelosuppression limits optimal therapy in cardiosurgical patients with deep-seated infections at current doses.

Methods

Adult patients who received a cardiac surgery intervention and linezolid for a documented or presumed serious Gram-positive infection were evaluated. Therapeutic monitoring data, dosing, concomitant medications, and other pertinent laboratory data were collected retrospectively. A population pharmacokinetic model was constructed to identify covariates and test potential drug-drug interactions that may account for interpatient variability. Simulations from the final model identified doses that achieve a target therapeutic trough concentration of 2-8 mg/L.

Results

This study included 150 patients (79.3% male) with sepsis and hospital acquired pneumonia in 71.7% as the primary indication. The population had a median (min-max) age, body weight and estimated glomerular filtration rate (eGFR) of 66 (30–85) years, 76 (45–130) kg and 46.8 (4.9–153.7) mL/min, respectively. The standard linezolid dosage regimen achieved the therapeutic range in only 54.7% of patients. Lower than standard doses were necessary in the majority of patients (77%). A two-compartment Michaellis-Menten clearance model with weight, kidney function, and the number of interacting drugs were identified as covariates that best fit the concentration-time data. Cyclosporine had the greatest effect on lowering the maximum elimination rate (Vmax) of linezolid. Empiric linezolid doses of 300 to 450 mg every 12 hours based on eGFR and the number of interacting medications is suggested by this analysis.

Conclusions

Lower empiric linezolid doses in cardiosurgical patients may avoid toxicities. Confirmatory studies are necessary to verify these potential drug interactions.

Approach to patients with COVID-19 disease: the procedure in Udine

Coronavirus disease 2019 poses a serious threat to public health. The protocol developed at the Azienda Sanitaria Universitaria Friuli Centrale (Italy) is based on clinical data, laboratory tests, chest echography and HRCT. Several therapeutic options are considered, since patients vary in disease severity, evolution and co-morbidities and because so far there are no clear indications about therapeutic strategy based on randomized clinical trial. In this protocol chest echography has a central role in categorizing patient status, follow-up and decision-making.

Clinical presentation and immunological features of Post-Malaria Neurologic Syndrome: a case report and review of literature

Background

Malaria still represents a major health threat, in terms of both morbidity and mortality. Complications of malaria present a diversified clinical spectrum, with neurological involvement leading to the most serious related-conditions. The authors recently encountered a case of a 60-year old Italian man presenting with confusion, language disturbances and Parkinson-like syndrome 3 weeks after complete remission from severe Plasmodium falciparum cerebral malaria. Chemical and microbiological analysis revealed aseptic meningitis, diffuse encephalitis and abnormal immune-activation. Re-infection and recrudescence of infection were excluded. Further analysis excluded paraneoplastic and autoimmune causes of encephalitis. A diagnosis of Post-Malaria Neurological Syndrome (PMNS) was finally formulated and successfully treated with high dose of steroids.

Methods

A systematic research of current literature related to PMNS was performed.

Results

151 cases of PMNS were included, the majority of which occurred after severe P. falciparum infections. Four main clinical pattern were identified: 37% of the cases presented as “classical” PMNS, 36% presented as delayed cerebellar ataxia (DCA), 18% resembled acute inflammatory demyelinating polyneuropathy (AIDP), and 8% presented as acute disseminated encephalomyelitis (ADEM)-like form. Differentiation between different forms was not always simple, as clinical and radiological findings frequently overlap. Overall, in almost all of the tested cases, cerebrospinal fluid was found pathological; EEG revealed nonspecific encephalopathy in 30% of classical PMNS and 67% ADEM; imaging tests were found abnormal in 92% of ADEM-like forms. Pathogenesis remains unclear. An autoimmune mechanism is the most corroborated pathogenic hypothesis. Overall, the majority of PMNS cases revert without specific treatment. In most severe forms, high dose steroids, intravenous immunoglobulins, and plasmapheresis have been shown to improve symptoms.

Conclusions

PMNS is a disabling complication of malaria. The overall incidence is not known, due to frequent misdiagnosis and under-reporting. Pathogenesis is not also fully understood, but rapid response to immune-modulating treatment along with similarities to auto-immune neurological disease, strongly support a dysregulated immunological genesis of this condition. The lack of randomized controlled studies regarding therapeutic approaches is a major unmet need in this setting. A systematic collection of all the PMNS cases would be desirable, in order to increase awareness of this rare condition and to prospectively investigate the most appropriate management.

Comparative Population Pharmacokinetics of Darunavir in SARS-CoV-2 Patients vs. HIV Patients: The Role of Interleukin-6

Background

Darunavir is an anti-HIV protease inhibitor repurposed for SARS-CoV-2 treatment.

Objective

The aim of this study was to assess the population pharmacokinetics of darunavir in SARS-CoV-2 patients compared with HIV patients.

Methods

Two separate models were created by means of a nonlinear mixed-effect approach. The influence of clinical covariates on each basic model was tested and the association of significant covariates with darunavir parameters was assessed at multivariate regression and classification and regression tree (CART) analyses. Monte Carlo simulation assessed the influence of covariates on the darunavir concentration versus time profile.

Results

A one-compartment model well-described darunavir concentrations in both groups. In SARS-CoV-2 patients (n = 30), interleukin (IL)-6 and body surface area were covariates associated with darunavir oral clearance (CL/F) and volume of distribution (V_d), respectively; no covariates were identified in HIV patients (n = 25). Darunavir CL/F was significantly lower in SARS-CoV-2 patients compared with HIV patients (4.1 vs. 10.3 L/h; p < 0.001). CART analysis found that an IL-6 level of 18 pg/mL may split the SARS-CoV-2 population in patients with low versus high darunavir CL/F (mean ± standard deviation 3.47 ± 1.90 vs. 8.03 ± 3.24 L/h; proportion of reduction in error = 0.46). Median (interquartile range) darunavir CL/F was significantly lower in SARS-CoV-2 patients with IL-6 levels ≥ 18 pg/mL than in SARS-CoV-2 patients with IL-6 levels < 18 pg/mL or HIV patients (2.78 [2.16–4.47] vs. 7.24 [5.88–10.38] vs. 9.75 [8.45–13.79] L/h, respectively; p < 0.0001). Increasing IL-6 levels affected darunavir concentration versus time simulated profiles. We hypothesized that increases in IL-6 levels associated with severe SARS-CoV-2 disease may downregulate the cytochrome P450 (CYP) 3A4-mediated metabolism of darunavir.

Conclusions

This is a proof-of-concept of SARS-CoV-2 disease–drug interactions, and may support the need for optimal dose selection of sensitive CYP3A4 substrates in severe SARS-CoV-2 patients.

Electronic supplementary material

The online version of this article (10.1007/s40262-020-00933-8) contains supplementary material, which is available to authorized users.

Ceftobiprole and pneumonia in adults admitted to the emergency department is it time to assess a new therapeutic algorithm?

OBJECTIVE

Ceftobiprole is an advance generation cephalosporin which has broad-spectrum bacterial activity (both against Gram-positive and negative pathogens) and was approved for the treatment of community-acquired pneumonia (CAP) and non-ventilated hospital-acquired pneumonia (HAP) in most European countries. We aimed to evaluate the efficacy and safety of ceftobiprole in the treatment of pneumonia in a cohort of severely ill patients admitted to the emergency department (ED).

METHODS

1-year observational retrospective mono-centric study. Were defined two primary endpoints: first, to evaluate the clinical cure at the test-of-cure (TOC); the second, to evaluate the early improvement, defined as a reduction of symptoms and inflammatory parameters 72 hours after the start of treatment. The secondary endpoint is to evaluate the reduction of antibiotic "burden" using ceftobiprole despite standard of care in severe hospital-acquired pneumonia.

RESULTS

During the study period, a total of 48 patients with severe pneumonia received ceftobiprole: twenty-two patients (45.8%) as empiric therapy, 9 (18.5%) as a de-escalation option from previous combination therapies, 13 patients (27.1%) as an escalation therapy from ceftriaxone or amoxicillin/clavulanate and four patients (8.3%) as a targeted therapy based on microbiological results. Ceftobiprole mean duration therapy was 10.2 days. Forty-six patients with severe pneumonia had an early clinical improvement 72 hours after the start of treatment (95.8%). In general, ceftobiprole was well tolerated; only one patient suspended the drug because of poor tolerability. The clinical cure at TOC was 85.4% and 30-days crude mortality was 10.4%.

CONCLUSIONS

This study confirms that ceftobiprole is effective in severely ill patients with pneumonia at risk of poor outcomes.

Risk factors for ventilator associated pneumonia due to carbapenemase-producing Klebsiella pneumoniae in mechanically ventilated patients with tracheal and rectal colonization

BACKGROUND

The aim of this study was to identify the risk factors for ventilator associated pneumonia (VAP) due to Klebsiella pneumoniae carbapenemase-producing K (KPC-Kp) development in ICU patients with documented rectal and tracheal colonization.

METHODS

We performed a retrospective, matched case-control study in a medical-surgical ICU (January 2011-December 2013) comparing 30 patients who developed KPC-Kp VAP during the ICU stay to 60 colonized patients not developing KPC-Kp VAP. Analysed risk factors included: age, sex, SAPS II and SOFA scores, comorbidities, type and length of antibiotic therapy, previous non KPC-Kp infections, time between admission to rectal and tracheal colonization.

RESULTS

Several risk factors were more frequent among patients who developed KPC-Kp pneumonia versus matched colonized controls: previous infection not related to KPC-Kp (P<0.001), duration of previous antibiotic therapy before (P<0.001) and after (P=0.002) KPC-Kp colonization. Amoxicillin/clavulanic acid prophylaxis was administered in 17% of VAP patients versus 73% of patients not developing VAP (P<0.001). Multivariate conditional logistic regression analysis identified several significant independent risk factors favoring KPC-Kp VAP in patients colonized at multiple sites: previous non KPC-Kp infections (OR: 2.046), duration of previous antibiotic therapy before (OR: 1.309) and after (OR: 1.122) KPC-Kp colonization; antibiotic therapy with amoxicillin/clavulanic acid prophylaxis (<48 hours) was associated with reduced risk of KPC-Kp VAP (OR: 0.987).

CONCLUSIONS

In rectal and tracheal KPC-Kp colonized patients, prolonged antibiotic therapy administered for non KPC-Kp infection predisposes patients to subsequent KPC-Kp VAP. Short prophylaxis of early pneumonia with amoxicillin/clavulanic acid, reducing the need for subsequent antibiotic use, may be associated with reduced risk for KPC-Kp VAP.

Determination of PCT on admission is a useful tool for the assessment of disease severity in travelers with imported Plasmodium falciparum malaria

Procalcitonin (PCT) and C-reactive protein (CRP) may be useful to predict complicated forms of malaria. A total of 30 consecutive travelers diagnosed with Plasmodium falciparum malaria over a two-year period were included in the study. Patients with complicated Plasmodium falciparum malaria showed higher levels of parasitemia (P = 0.0001), PCT (P = 0.0018), CRP (P = 0.0005), bilirubinemia (P = 0.004), and a lower platelet count (P<0.0001) compared with patients with uncomplicated forms. PCT levels above 5 ng/mL showed the highest value of specificity (0.86) and positive predictive factor (0.67) among other parameters, and equal sensitivity (0.67) was displayed by CRP levels above 150 mg/dl. None of the patients with complicated malaria showed PCT levels within normal limits (<0.5 ng/ml). Both PCT and CRP correlated with parasitemia (P<0.001) and showed areas under ROC curve of 0.83. At multivariate analysis, only PCT was associated with an increased risk of complicated malaria (OR 8.2, IC 95% 1.2-57.2, P = 0.03). The determination of PCT on admission showed better results compared to CRP, platelet count, and bilirubinemia and can be useful in non-endemic areas for the initial clinical assessment of disease severity in travelers with Plasmodium falciparum malaria.

Delafloxacin for the treatment of respiratory and skin infections

INTRODUCTION

There has been a striking increase in the emergence of multidrug-resistant pathogens in recent times. Delafloxacin is a novel, broad-spectrum fluoroquinolone with antimicrobial activity against resistant Gram-positive, Gram-negative and anaerobic organisms. It has the potential to treat a variety of infections including complicated skin and skin structure infections and respiratory tract infections.

AREAS COVERED

In this review, the authors report the microbiological spectrum of activity of delafloxacin as well as its pharmacokinetic characteristics. They also report the results of recent studies investigating its safety and efficacy.

EXPERT OPINION

The profile of delafloxacin offers several advantages. Delafloxacin presents a broad spectrum of activity against pathogens involved in respiratory infections and complicated skin and skin structure infections (SSSIs), including methicillin-resistant Staphylococcus aureus. It has also shown activity against Gram-negative pathogens, such as quinolone-susceptible and -resistant strains of Escherichia coli and Klebsiella pneumoniae and quinolone-susceptible Pseudomonas aeruginosa. The availability of an oral formulation supports its use in sequential therapy. The efficacy and tolerability of delafloxacin have been demonstrated in Phase II clinical trials in comparison with moxifloxacin for respiratory infections and linezolid and vancomycin in SSSIs. Compared with other quinolones such as moxifloxacin, delafloxacin showed comparable efficacy and a lower rate of adverse effects. The results of new Phase III studies are awaited to confirm delafloxacin's future applications in the treatment of SSSIs.

Linezolid-resistant staphylococcal bacteraemia: A multicentre case-case-control study in Italy

The aim of this multicentre study was to analyse the characteristics of patients with bloodstream infections due to staphylococcal strains resistant to linezolid. This was a retrospective case-case-control study of patients hospitalised in three large teaching hospitals in Italy. A linezolid-resistant (LIN-R) Staphylococcus spp. group and a linezolid-susceptible (LIN-S) Staphylococcus spp. group were compared with control patients to determine the clinical features and factors associated with isolation of LIN-R strains. All LIN-R Staphylococcus spp. strains underwent molecular typing. Compared with the LIN-S group, central venous catheters were the main source of infection in the LIN-R group. The LIN-R and LIN-S groups showed a similar incidence of severe sepsis or septic shock, and both showed a higher incidence of these compared with the control group. Overall, patients in the LIN-R group had a higher 30-day mortality rate. Multivariate analysis found previous linezolid therapy, linezolid therapy >14 days, antibiotic therapy in the previous 30 days, antibiotic therapy >14 days, previous use of at least two antibiotics and hospitalisation in the previous 90 days as independent risk factors associated with isolation of a LIN-R strain. The G2576T mutation in domain V of 23S rRNA was the principal mechanism of resistance; only one strain of Staphylococcus epidermidis carried the cfr methylase gene (A2503), together with L4 insertion (71GGR72) and L3 substitution (H146Q). LIN-R strains are associated with severe impairment of clinical conditions and unfavourable patient outcomes. Reinforcement of infection control measures may have an important role in preventing these infections.