Comparison of BD Phoenix and disk diffusion to broth microdilution for determining cefepime susceptibility among carbapenem-resistant Enterobacterales

There are increasing reports of carbapenem-resistant Enterobacterales (CRE) that test as cefepime-susceptible (S) or susceptible-dose dependent (SDD). However, there are no data to compare the cefepime testing performance of BD Phoenix automated susceptibility system (BD Phoenix) and disk diffusion (DD) relative to reference broth microdilution (BMD) against carbapenemase-producing (CPblaKPC-CRE) and non-producing (non-CP CRE) isolates. Cefepime susceptibility results were interpreted according to CLSI M100Ed32. Essential agreement (EA), categorical agreement (CA), minor errors (miEs), major errors (MEs), and very major errors (VMEs) were calculated for BD Phoenix (NMIC-306 Gram-negative panel) and DD relative to BMD. Correlates were also analyzed by the error rate-bounded method. EA and CA for CPblaKPC-CRE isolates (n = 64) were <90% with BD Phoenix while among non-CP CRE isolates (n = 58), EA and CA were 96.6%, and 79.3%, respectively. CA was <90% with DD for both cohorts. No ME or VME was observed for either isolate cohort; however, miEs were >10% for CPblaKPC-CRE and non-CP CRE with BD Phoenix and DD tests. For error rate-bounded method, miEs were <40% for IHigh + 1 to ILow - 1 ranges for CPblaKPC-CRE and non-CP CRE with BD Phoenix. Regarding disk diffusion, miEs were unacceptable for all MIC ranges among CPblaKPC-CRE. For non-CP CRE isolates, only IHigh + 1 to ILow - 1 range was acceptable at 37.2%. Using this challenge set of genotypic-phenotypic discordant CRE, the BD Phoenix MICs and DD susceptibility results trended higher (toward SDD and resistant phenotypes) relative to reference BMD results yielding lower CA. These results were more prominent among CPblaKPC-CRE than non-CP CRE.

Treatment of infections caused by multidrug-resistant Gram-negative bacilli: a practical approach by the Italian (SIMIT) and French (SPILF) Societies of Infectious Diseases

INTRODUCTION

The emergence of multidrug-resistant Gram-negative bacilli, and the development of new antibiotics have complexified selection of optimal regimens. International guidelines are valuable tools, though limited by scarcity of high-quality randomized trials in many situations.

METHODS

A panel of experts from the French and Italian Societies of Infectious Diseases aimed to address unresolved issues in clinical practice based on their experience, updated literature review, and open discussions.

RESULTS

The panel reached a consensus for the following 'first-choices': i) cefepime for ventilator-acquired pneumonia due to AmpC β-lactamase-producing Enterobacterales; ii) The β-lactam/β-lactamase inhibitors combination most active in vitro, or cefiderocol combined with fosfomycin, and aerosolized colistin or aminoglycosides, for severe pneumonia due to Pseudomonas aeruginosa resistant to ceftolozane-tazobactam; iii) high-dose piperacillin-tazobactam (including loading dose and continuous infusion), for complicated urinary tract infections (cUTIs) caused by ESBL-producing Enterobacterales with piperacillin-tazobactam MIC ≤8 mg/L; iv) high-dose cefepime for cUTIs due to AmpC β-lactamase-producing Enterobacterales other than Enterobacter species if cefepime MIC ≤2 mg/L; v) ceftolozane-tazobactam or ceftazidime-avibactam plus metronidazole for intra-abdominal infections (IAIs) due to 3rd generation cephalosporin-resistant Enterobacterales; vi) ceftazidime-avibactam plus aztreonam plus metronidazole for IAIs due to metallo β-lactamase-producing Enterobacterales; vii) ampicillin-sulbactam plus colistin for bloodstream infections (BSIs) caused by carbapenem-resistant Acinetobacter baumannii (CRAB); viii) meropenem-vaborbactam for BSI caused by KPC-producing Enterobacterales; ix) ceftazidime-avibactam plus fosfomycin for neurological infections caused by carbapenem-resistant P. aeruginosa.

CONCLUSIONS

These expert choices were based on the necessary balance between antimicrobial stewardship principles, and the need to provide optimal treatment for individual patients in each situation.

Intermittent Administration of Cefepime in Adult ICU Patients with Gram-Negative Bacilli Bacteremia: A Randomized Double-Blind Clinical Study

INTRODUCTION

The objective of this study was to compare the continuous infusion of cefepime with the intermittent infusion in patients with sepsis caused by Gram-negative bacilli (GNB).

METHODS

Randomized 1:1 multicenter double-blinded placebo-controlled study with allocation concealment; multicenter study in the intensive care units of Colombia. Patients with sepsis, severe sepsis or septic shock, and GNB-suspected bacteremia. Cefepime was administered for 7 to 14 days over 30 m intermittently every 8 h over 24 h plus continuous saline solution (0.9%) (G1) or 3 g administered continuously plus saline solution every 8 h (0.9%) (G2). The percentage of clinical response at 3, 7, and 14 days, relapse at 28 days, and mortality at discharge were measured.

RESULTS

The recruitment was stopped at the suggestion of the Institutional Review Board (IRB) following an FDA alert about cefepime. Thirty-two patients were randomized; 25 received the intervention, and GNB bacteremia was confirmed in 16 (9 G1 and 7 G2). Favorable clinical response in days 3, 7, and 14 was 88.8%, 88.8%, and 77.8% (G1) and was similar for G2 (85.7%). There were no relapses or deaths in G2, while in G1, one relapse and two deaths were observed.

CONCLUSIONS

The results of this study support the use of cefepime for the treatment of Gram-negative infections in critically ill patients, but we could not demonstrate differences between continuous or intermittent administration because of the small sample size, given the early suspension of the study.

Pharmacokinetic Analysis of Intravenous Push Cefepime in Burn Patients with Augmented Renal Clearance

Patients with augmented renal clearance (ARC) are a subset of critically ill patients including burn patients that exhibit increased renal elimination of medications beyond that of similarly injured patients. Currently approved maximum regimens of medications primarily eliminated by the kidney, such as cefepime (>90% unchanged in the urine), may be inadequate (eg, compromising the bactericidal activity of cefepime) in patients with ARC. Due to recent resource limitations, centers have changed infusion practices of commonly prescribed medications to intravenous push (IVP), potentially exacerbating the problem of maintaining bactericidal cefepime concentrations. The hypothesis of the study was patients with ARC are not currently achieving adequate target attainment, when receiving cefepime 2 g every 8 h IVP. Eight blood samples were collected from each patient, and concentrations measured via LC-MS/MS. WinNonlin (version 8.3) was used to estimate the pharmacokinetic parameters of cefepime and simulate plasma concentrations of cefepime in each of the ten subjects. Simulations of cefepime plasma concentrations produced by a 2 g dose given every 8 h and a 1 g dose given every 4 h were performed and the time above a MIC of 4 mg/L, 8 mg/L, and 16 mg/L compared. The 2 g every 8 h regimen remained above the breakpoints for 92%, 85%, and 71% of the dosing interval, respectively. The 1 g every 4 h regimen remained above the same breakpoints at a frequency of 100%, 99%, and 92% of the dosing interval. Giving cefepime 1 g every 4 h is a simple approach to increase the likelihood of maintaining the optimal bactericidal activity of cefepime in patients with ARC.

Cefepime-Induced Generalized Fixed Drug Eruption With Morbilliform Rash

Fixed drug eruption (FDE) is a cutaneous reaction that characteristically recurs in the same locations upon re-exposure to the offending drug(s). The typical presentation of FDEs is single or multiple violaceous plaques with hyperpigmentation due to inflammation. The causative agents for FDEs include antibiotics, nonsteroidal anti-inflammatory drugs (NSAIDs), acetaminophen, barbiturates, and anticonvulsants. We present an interesting case of a generalized fixed drug eruption secondary to cefepime that resolved with the cessation of the offending drug and the institution of antihistamines and topical steroids.

Negative myoclonus as a manifestation of cefepime neurotoxicity

Negative myoclonus may present in the early stages of cefepime neurotoxicity. Cefepime neurotoxicity typically presents as reduced consciousness, myoclonus, and seizures; however, negative myoclonus is uncommon. This video shows an older woman with cefepime neurotoxicity that presented as a negative myoclonus of the upper limbs.

The Impact of Cefepime and Ampicillin/Sulbactam on Preventing Post-Cesarean Surgical Site Infections, Randomized Controlled Trail

Over the previous three decades, the rate of caesarean sections performed worldwide has grown exponentially. In comparison to a vaginal birth, the risk of all postpartum infections is higher with a cesarean section. One of the key factors contributing to maternal morbidity is the development of infectious complications in the surgical site after a caesarean section. The primary goal of the research was to compare the efficiency of using ampicillin/sulbactam (AMS) and cefepime (CEF) to reduce the incidence of surgical site infections (SSI) following caesarean delivery. This prospective randomized study was conducted among 200 pregnant women scheduled for elective cesarean section. They were collected from the Obstetrics and Gynecology department of Beni-Suef University Hospital, and then they were randomly assigned into two groups. Group (A) received cefepime 30 min before and 12 h after cesarean delivery, while group (B) received ampicillin/sulbactam 30 min before and 12 h after cesarean delivery. The groups were matched regarding the baseline women characteristics. Comparing the cefepime to the ampicillin/sulbactam revealed that the cefepime significantly decreased superficial SSI from 27% to 14% (0.023). A significant decrease was observed in deep SSI with cefepime compared to ampicillin/sulbactam from 24% to 13% (p-value 0.045). Interestingly, when the cefepime was compared to the ampicillin/sulbactam, we noted that the incidence of endometritis significantly decreased from 13% to 5% (p = 0.048). A noted decrease in post-operative fever in cefepime as compared to ampicillin/sulbactam from 18% to 13% (p-value = 0.329). Receiving prophylactic cefepime pre- and post-cesarean delivery significantly decreases post-operative wound infection and endometritis.

Cefepime Daily Exposure and the Associated Impact on the Change in Sequential Organ Failure Assessment Scores and Vasopressors Requirement in Critically Ill Patients Using Repeated-Measures Mixed-Effect Modeling

IMPORTANCE

Sepsis and septic shock are major healthcare problems that need early and appropriate management.

OBJECTIVES

To evaluate the association of daily cefepime pharmacokinetic/pharmacodynamic (PK/PD) parameters with change in Sequential Organ Failure Assessment (SOFA) score and vasopressors requirement.

DESIGN SETTING AND PARTICIPANTS

This is a retrospective study. Adult ICU patients who received cefepime for Gram-negative pneumonia or bloodstream infection (BSI) and had cefepime concentrations measured were included. Daily cefepime exposure was generated and PK/PD parameters calculated for patients. Repeated-measures mixed-effect modeling was used to evaluate the impact of PK/PD on the outcomes.

MAIN OUTCOMES AND MEASURES

Change in daily SOFA score and vasopressors requirement.

RESULTS

A total of 394 and 207 patients were included in the SOFA and vasopressors analyses, respectively. The mean (±sd) age was 55 years (19) and weight 81 kg (29). For the change in SOFA score, daily SOFA score, mechanical ventilation, renal replacement therapy, and number of vasopressors were included. In the vasopressors analysis, daily SOFA score, day of therapy, and hydrocortisone dose were significant covariates in the final model. Achieving cefepime concentrations above the minimum inhibitory concentration (MIC) (T>MIC) for 100% of the dosing interval was associated with 0.006 µg/kg/min decrease in norepinephrine-equivalent dose. Cefepime PK/PD did not have an impact on the daily change in SOFA score.

CONCLUSIONS AND RELEVANCE

Achieving 100% T>MIC was associated with negligible decrease in vasopressors requirement in ICU patients with Gram-negative pneumonia and BSI. There was no impact on the change in SOFA score.

Transcending the challenge of evolving resistance mechanisms in Pseudomonas aeruginosa through β-lactam-enhancer-mechanism-based cefepime/zidebactam

Multi-drug resistant (MDR) Pseudomonas aeruginosa harbor a complex array of β-lactamases and non-enzymatic resistance mechanisms. In this study, the activity of a β-lactam/β-lactam-enhancer, cefepime/zidebactam, and novel β-lactam/β-lactamase inhibitor combinations was determined against an MDR phenotype-enriched, challenge panel of P. aeruginosa (n = 108). Isolates were multi-clonal as they belonged to at least 29 distinct sequence types (STs) and harbored metallo-β-lactamases, serine β-lactamases, penicillin binding protein (PBP) mutations, and other non-enzymatic resistance mechanisms. Ceftazidime/avibactam, ceftolozane/tazobactam, imipenem/relebactam, and cefepime/taniborbactam demonstrated MIC90s of >128 mg/L, while cefepime/zidebactam MIC90 was 16 mg/L. In a neutropenic-murine lung infection model, a cefepime/zidebactam human epithelial-lining fluid-simulated regimen achieved or exceeded a translational end point of 1-log10 kill for the isolates with elevated cefepime/zidebactam MICs (16-32 mg/L), harboring VIM-2 or KPC-2 and alterations in PBP2 and PBP3. In the same model, to assess the impact of zidebactam on the pharmacodynamic (PD) requirement of cefepime, dose-fractionation studies were undertaken employing cefepime-susceptible P. aeruginosa isolates. Administered alone, cefepime required 47%-68% fT >MIC for stasis to ~1 log10 kill effect, while cefepime in the presence of zidebactam required just 8%-16% for >2 log10 kill effect, thus, providing the pharmacokinetic/PD basis for in vivo efficacy of cefepime/zidebactam against isolates with MICs up to 32 mg/L. Unlike β-lactam/β-lactamase inhibitors, β-lactam enhancer mechanism-based cefepime/zidebactam shows a potential to transcend the challenge of ever-evolving resistance mechanisms by targeting multiple PBPs and overcoming diverse β-lactamases including carbapenemases in P. aeruginosa.IMPORTANCECompared to other genera of Gram-negative pathogens, Pseudomonas is adept in acquiring complex non-enzymatic and enzymatic resistance mechanisms thus remaining a challenge to even novel antibiotics including recently developed β-lactam and β-lactamase inhibitor combinations. This study shows that the novel β-lactam enhancer approach enables cefepime/zidebactam to overcome both non-enzymatic and enzymatic resistance mechanisms associated with a challenging panel of P. aeruginosa. This study highlights that the β-lactam enhancer mechanism is a promising alternative to the conventional β-lactam/β-lactamase inhibitor approach in combating ever-evolving MDR P. aeruginosa.

Comparison of Outcomes in Neonates Receiving Cefepime or Ceftazidime

OBJECTIVES

Cefepime and ceftazidime are alternatives to cefotaxime for management of Gram-negative infections in neonates. The objective was to evaluate neonatal outcomes when receiving cefepime or ceftazidime.

METHODS

This was a single center, retrospective analysis of neonates exposed to at least 24 hours of cefepime or ceftazidime between June 1, 2018, and June 1, 2021. The primary outcome was incidence of culture-positive, late-onset sepsis after initial exposure. Secondary outcomes included culture-negative, respiratory, urinary tract, and resistant infections; necrotizing enterocolitis; length of stay; age at discharge; mortality; and adverse effects.

RESULTS

A total of 105 neonates were included (cefepime, n = 50; ceftazidime, n = 55). Baseline characteristics were similar except more cumulative days of antibiotics (25.0 [IQR, 9.3-47.0] versus 9.0 [IQR, 4.0-23.5], p = 0.01), central line days (11.0 [IQR, 6.0-40.0] versus 6.5 [IQR, 0.0-11.5], p = 0.001), and ventilator days (13.0 [IQR, 2.3-48.0] versus 4.0 [IQR, 0.0-25.0], p = 0.02) were found in the cefepime group than in the ceftazidime group. There was no difference in culture-positive sepsis after the initial antibiotic course (8.0% versus 3.6%, p = 0.42). Statistical differences were seen in select secondary outcomes including treated respiratory infections (16.0% versus 1.8%, p = 0.01), length of stay greater than 30 days (72.0% versus 50.9%, p = 0.03), and mortality (26.0% versus 9.1%, p = 0.02). These differences were not observed in analyses adjusted for ventilator days.

CONCLUSIONS

This analysis found no difference in culture-positive sepsis in neonates exposed to cefepime versus ceftazidime. Moreover, there were no differences in secondary outcomes in adjusted analyses. Further research is needed to assess neonatal outcomes in a larger analysis.

Unmasking the Silent Threat: Cefepime-Induced Thrombocytopenia

Cefepime, a commonly prescribed fourth-generation cephalosporin, is well-known for its broad-spectrum antibacterial activity. While adverse drug reactions associated with cefepime are well documented, thrombocytopenia as a rare complication has gained attention due to its potential severity. Symptomatic patients present with purpura (bruising), petechiae (small red or purple spots on the skin), and mucosal bleeding. Drug-induced thrombocytopenia can be initiated by myelosuppression by halting platelet formation in the bone marrow or by a drug-induced immune thrombocytopenia reaction. We present a case of a 71-year-old male who experienced thrombocytopenia secondary to cefepime use. We further discussed the underlying mechanisms of cefepime-induced thrombocytopenia, highlighting the need for increased vigilance in monitoring platelet counts during cefepime administration. This case underscores the importance of recognizing and managing this uncommon but potentially life-threatening adverse reaction in clinical practice.

The Impact of ESBLs-Positive Escherichia coli's Resistance to Cefepime and Its Guidance for Clinical Treatment

Background

Escherichia coli (E. coli) is a common pathogen in bloodstream infections (BSI), and the production of extended-spectrum beta-lactamases (ESBLs) is its main mechanism of resistance. However, the impact of different ESBL genotypes of E. coli on the resistance to Cefepime (FEP) remains unclear.

Methods

A total of 2356 cases of BSI patients were collected. The experimental group included 188 ESBL-positive E. coli strains that were resistant to FEP but sensitive to ceftazidime (CAZ). Antibiotic usage and resistance rates were evaluated through antimicrobial susceptibility testing and antibiotic usage records. The ESBL genotypes were identified, and the minimum inhibitory concentration (MIC) and mutant prevention concentration (MPC) of FEP were determined.

Results

In ESBL-positive E. coli, three ESBL genotypes were identified: 188 strains of CTX-M, 130 strains of TEM-1, and 26 strains of OXA-10. Among them, 124 strains carried both CTX-M-9 and TEM-1 genotypes, 22 strains carried two CTX-M genotypes (CTX-M-1 and CTX-M-2), 20 strains carried both CTX-M-9 and OXA-10, and 6 strains carried three genotypes (CTX-M-9, CTX-TEM-1, and OXA-10). The MIC50, MIC90, MPC50, and MPC90 of the 188 ESBL-positive E. coli were 64, 256, 128, and 528, respectively. The MIC values ranged from 32 to 256, while the MPC values ranged from 64 to 528. The MIC50, MIC90, MPC50, and MPC90 of the 40 ESBL-negative E. coli were 0.5, 1, 64, and 128, respectively; the MIC values ranged from 0.25 to 4, while the MPC values ranged from 32 to 256, respectively.

Conclusion

ESBL-positive E. coli induces an increase in the MIC value of FEP, leading to an increase in FEP resistance. The inoculation effect also causes a significant increase in the MPC value of FEP, especially the increase in selection index value, indicating selective enrichment and amplification of drug-resistant mutants, resulting in clinical treatment failure.

Treatment Outcomes for Carbapenem-Resistant and Cephalosporin-Susceptible Pseudomonas aeruginosa Pneumonia

BACKGROUND

Carbapenem-resistant (Car-R) Pseudomonas aeruginosa is an urgent threat. These isolates may remain susceptible to traditional noncarbapenem antipseudomonal β-lactams, but it is unclear if carbapenem resistance impacts the effectiveness of these agents.

OBJECTIVE

The purpose of this study was to compare clinical outcomes in Car-R and cephalosporin-susceptible (Ceph-S) P. aeruginosa pneumonia treated with cefepime versus other susceptible agents.

METHODS

This retrospective cohort study evaluated patients diagnosed with hospital-acquired or ventilator-associated pneumonia who had a respiratory isolate of Car-R Ceph-S P. aeruginosa. Patients were excluded if they had polymicrobial respiratory cultures, other concomitant infections, empyema, death within 3 days of index culture, or received less than 3 days of susceptible therapy. Patients treated with cefepime were compared to other susceptible therapies. The primary endpoint was 30-day in-hospital mortality.

RESULTS

Eighty-seven patients were included: cefepime, n = 61; other susceptible therapies, n = 26. There were no differences in 30-day in-hospital mortality between cefepime and other susceptible therapies (19.6% vs. 19.2%, p value = 0.719). In addition, there were no differences between clinical cure rates (cefepime 65.6% vs. other therapies 72 %, p value = 0.47). In multivariate logistic regression, treatment with cefepime (odds ratio [OR], 0.57; 95% confidence interval [CI], 0.11-2.52) was not independently associated with 30-day in-hospital mortality.

CONCLUSION AND RELEVANCE

For the treatment of Car-R Ceph-S P. aeruginosa pneumonia, cefepime showed similar rates of 30-day in-hospital mortality and clinical outcomes when compared to other susceptible therapies. Cefepime may be utilized to conserve novel β-lactam and β-lactamase inhibitors.

Synergistic Effects of Gentamicin, Cefepime, and Ciprofloxacin on Biofilm of Pseudomonas aeruginosa

Background

Pseudomonas aeruginosa is an opportunistic pathogen involved in number of hospital-acquired infections such as catheter-associated urinary tract infections, bacteremia, septicemia, skin infections, and ventilator-associated pneumoniae. Biofilm formation is an important trait implicated in chronic infections, such as cystic fibrosis and chronic pulmonary obstruction. We evaluated effects of gentamicin, cefepime, and ciprofloxacin on biofilm of P. aeruginosa.

Materials and Methods

A total of 266 isolates were collected from the Armed Forces Institute of Pathology (AFIP). Antibiotic susceptibility was assessed by double disk synergy testing. ESBL and carbapenemase detection was performed by phenotypic testing. Molecular screening of the genes was done by PCR. Micro-dilution broth method was used to determine minimum inhibitory concentrations of antibiotics. Biofilm formation was done by micro-titer plate assay.

Results

Overall, 20% of the P. aeruginosa isolates were extensively drug-resistant (XDR-PA), and 25% were multi-drug-resistant (MDR-PA). Likewise, 43% of the isolates were ESBL producers, and carbapenemase production was detected in 40% of the isolates. Molecular analysis confirmed occurrence of different resistant factors in ESBL-positive isolates; 67% carried blaTEM, 62% blaCTXM-15, 41% blaSHV, 34% blaCTXM-14, and 33% blaOXA-1. In addition, 68% of the carbapenem-resistant isolates were positive for blaNDM-1, 25% for blaOXA-48, and 22% for blaKPC-2. Biofilm formation was assessed for 234 isolates, out of which 28% were strong biofilm formers. Moderate and weak biofilm formers constituted 46% and 23%, respectively. Overall, ciprofloxacin, levofloxacin, and cefepime showed inhibitory effects on P. aeruginosa biofilms. Antibiotics in combination showed strong synergistic effects (ciprofloxacin and cefepime), while gentamicin and cefepime resulted in complete eradication of P. aeruginosa biofilm.

Conclusion

We confirm strong synergistic effects of gentamicin and cefepime that completely eradicated P. aeruginosa biofilm. We further confirm inhibitory effects of ciprofloxacin, levofloxacin, and cefepime on P. aeruginosa biofilms. Hence, combination therapy can be more effective against biofilm-associated infections.

A Large-Scale Multicenter Retrospective Study on Nephrotoxicity Associated With Empiric Broad-Spectrum Antibiotics in Critically Ill Patients

BACKGROUND

Evidence regarding acute kidney injury associated with concomitant administration of vancomycin and piperacillin-tazobactam is conflicting, particularly in patients in the ICU.

RESEARCH QUESTION

Does a difference exist in the association between commonly prescribed empiric antibiotics on ICU admission (vancomycin and piperacillin-tazobactam, vancomycin and cefepime, and vancomycin and meropenem) and acute kidney injury?

STUDY DESIGN AND METHODS

This was a retrospective cohort study using data from the eICU Research Institute, which contains records for ICU stays between 2010 and 2015 across 335 hospitals. Patients were enrolled if they received vancomycin and piperacillin-tazobactam, vancomycin and cefepime, or vancomycin and meropenem exclusively. Patients initially admitted to the ED were included. Patients with hospital stay duration of < 1 h, receiving dialysis, or with missing data were excluded. Acute kidney injury was defined as Kidney Disease: Improving Global Outcomes stage 2 or 3 based on serum creatinine component. Propensity score matching was used to match patients in the control (vancomycin and meropenem or vancomycin and cefepime) and treatment (vancomycin and piperacillin-tazobactam) groups, and ORs were calculated. Sensitivity analyses were performed to study the effect of longer courses of combination therapy and patients with renal insufficiency on admission.

RESULTS

Thirty-five thousand six hundred fifty-four patients met inclusion criteria (vancomycin and piperacillin-tazobactam, n = 27,459; vancomycin and cefepime, n = 6,371; vancomycin and meropenem, n = 1,824). Vancomycin and piperacillin-tazobactam was associated with a higher risk of acute kidney injury and initiation of dialysis when compared with that of both vancomycin and cefepime (Acute kidney injury: OR, 1.37 [95% CI, 1.25-1.49]; dialysis: OR, 1.28 [95% CI, 1.14-1.45]) and vancomycin and meropenem (Acute kidney injury: OR, 1.27 [95%, 1.06-1.52]; dialysis: OR, 1.56 [95% CI, 1.23-2.00]). The odds of acute kidney injury developing was especially pronounced in patients without renal insufficiency receiving a longer duration of vancomycin and piperacillin-tazobactam therapy compared with vancomycin and meropenem therapy.

INTERPRETATION

VPT is associated with a higher risk of acute kidney injury than both vancomycin and cefepime and vancomycin and meropenem in patients in the ICU, especially for patients with normal initial kidney function requiring longer durations of therapy. Clinicians should consider vancomycin and meropenem or vancomycin and cefepime to reduce the risk of nephrotoxicity for patients in the ICU.

Cefepime Population Pharmacokinetics, Antibacterial Target Attainment, and Estimated Probability of Neurotoxicity in Critically Ill Patients

Cefepime has been reported to cause concentration-related neurotoxicity, especially in critically ill patients with renal failure. This evaluation aimed to identify a dosing regimen providing a sufficient probability of target attainment (PTA) and the lowest justifiable risk of neurotoxicity in critically ill patients. A population pharmacokinetic model was developed based on plasma concentrations over four consecutive days obtained from 14 intensive care unit (ICU) patients. The patients received a median dose of 2,000 mg cefepime by 30-min intravenous infusions with dosing intervals of every 8 h (q8h) to q24h. A time that the free drug concentration exceeds the MIC over the dosing interval (fT>MIC) of 65% and an fT>2×MIC of 100% were defined as treatment targets. Monte Carlo simulations were carried out to identify a dosing regimen for a PTA of 90% and a probability of neurotoxicity not exceeding 20%. A two-compartment model with linear elimination best described the data. Estimated creatinine clearance was significantly related to the clearance of cefepime in nondialysis patients. Interoccasion variability on clearance improved the model, reflecting dynamic clearance changes. The evaluations suggested combining thrice-daily administration as an appropriate choice. In patients with normal renal function (creatinine clearance, 120 mL/min), for the pharmacodynamics target of 100% fT>2×MIC and a PTA of 90%, a dose of 1,333 mg q8h was found to be related to a probability of neurotoxicity of ≤20% and to cover MICs up to 2 mg/L. Continuous infusion appears to be superior to other dosing regimens by providing higher efficacy and a low risk of neurotoxicity. The model makes it possible to improve the predicted balance between cefepime efficacy and neurotoxicity in critically ill patients. (This study has been registered at ClinicalTrials.gov under registration no. NCT01793012).

Drug reaction with eosinophilia and systemic symptoms (DRESS): an unusual manifestation of multi-visceral abnormalities and long-term outcome

Drug reaction with eosinophilia and systemic symptoms (DRESS), also known as drug induced hypersensitivity (DiHS) is a rare, however a severe hypersensitivity reaction with a mortality rate of up to 10%, accounting for 10 to 20% of all cutaneous drug reactions in hospitalized patients. The clinical features of DRESS/DiHS may be challenging to recognize and diagnose, since they are delayed, stepwise, and heterogeneous. The classic presentation of DRRSS/DiHS involves a combination of cutaneous, hematologic, and internal organ involvement with a 2 to 8 weeks latency between drug exposure and the onset of symptoms. Finding the culprit drug in our case was difficult as the patient was taking multiple antibiotics. Drugs such as vancomycin and cefepime used before the rash outbreak for post-reconstructive surgery for left toal knee arthroplasty (TKA) approximately four weeks before the onset of the rash are likely offending agents. This patient also had multi-visceral involvement with eosinophilia and systemic symptoms. The current treatment guidelines for DRESS/DiHS are primarily based on expert opinion, as no randomized control trials exist. After the prompt withdrawal of the offending drug, systemic corticosteroids seem to have shown the best outcome for patients. Delaying discontinuing offending medications and initiating corticosteroid treatment may lead to poor results. The present case emphasizes that the close observation of patients with drug eruption induced by antibiotics is imperative. Primary care team should be able to promptly diagnose patients with DRESS syndrome, detect causative drug, and play a crucial role in the timely evaluation and treatment to reduce mortality rate. The later phase disease relapse or autoimmune complications may occur up to 5 years following the initial presentation. Therefore, we advised the patient to have an outpatient follow up for appropriate testing, including but not limited to genetic susceptibility due to the high risk of relapse and emerging risk of autoimmune diseases.

Antimicrobial Resistance Pattern of Pseudomonas aeruginosa: An 11-Year Experience in a Tertiary Care Hospital in Makkah, Saudi Arabia

Purpose

Pseudomonas aeruginosa (P. aeruginosa) is a common causative pathogen in healthcare settings and displays increasing levels of resistance to common antimicrobial drugs. Its capacity to resist has been reported in multiple locations across the world. This study evaluates current levels of antibiotic resistance and seeks to understand antibiotic resistance patterns in the context of the clinical isolates of P. aeruginosa.

Methods

All clinical isolates were cultured at 37 °C for 24 h in different media: blood sheep agar, McConkey agar, and cystine-lactose-electrolyte-deficient agar (CLED), bacterial identification and antibiotic susceptibility patterns were determined using the Vitek-2 (bioMérieux) automated system.

Results

In total, there were 61,029 patient specimens, of which 5534 were identified as non-duplicated P. aeruginosa clinical isolates, most being from males aged over 60 years. The research findings revealed that the maximum antibiotic resistance associated with P. aeruginosa isolates was found in colistin (97%), which was followed by piperacillin/tazobactam (75.8%). The maximum resistance rates in P. aeruginosa isolates were found in relation to cefepime (42.7%,) which was followed by ciprofloxacin (34.3%).

Conclusion

The antibiotic resistance rate during the first six years of the research period was notably higher than in the last years, due to the application of infection control protocols and strict policies to control antibiotic prescriptions in all Saudi hospitals.

Outcomes of Intravenous Push versus Intermittent Infusion Administration of Cefepime in Critically Ill Patients

The equivalence of intravenous push (IVP) and piggyback (IVPB) administration has not been evaluated in the critically ill population for most medications, but it is especially relevant for antibiotics, such as cefepime, that exhibit time-dependent bactericidal activity. A single center, retrospective, observational pre/post-protocol change study included critically ill adults who received cefepime as empiric therapy between August 2015 and 2021. The primary outcome was treatment failure, which was defined as a composite of escalation of antibiotic regimen or all-cause mortality. Secondary outcomes included adverse drug events, days of cefepime therapy, total days of antibiotic therapy, and ICU and hospital length of stay. Outcomes were compared using Chi-squared, Mann Whitney U, and binary logistic regression as appropriate. A total of 285 patients were included: 87 IVPB and 198 IVP. Treatment failure occurred in 18% (n = 16) of the IVPB group and 27% (n = 54) of the IVP group (p = 0.109). There were no significant differences in secondary outcomes. Longer duration of antibiotics (odds ratio [OR] 1.057, 95% confidence interval [CI] 1.013-1.103), SOFA score (OR 1.269, 95% CI 1.154-1.397) and IVP administration of cefepime (OR 2.370, 95% CI 1.143-4.914) were independently associated with treatment failure. Critically ill patients who received IVP cefepime were more likely to experience treatment failure in an adjusted analysis. The current practice of IVP cefepime should be reevaluated, as it may not provide similar clinical outcomes in the critically ill population.

Comparison of Cefepime with Piperacillin/Tazobactam Treatment in Patients with Hospital-Acquired Pneumonia

Although cefepime and piperacillin/tazobactam are commonly prescribed for the treatment of hospital-acquired pneumonia (HAP), which one is the superior therapy remains unclear. Using Korean National Health Insurance Service data from January 2018 to December 2018, we compared the clinical outcomes of patients with HAP who were treated with cefepime and those treated with piperacillin/tazobactam. Data from 9955 adult patients with HAP, of whom 1502 (15%) received cefepime and 8453 (85%) received piperacillin/tazobactam, were retrieved for primary analysis. Tube feeding, suctioning, positioning care, and intensive care unit admission were more common among patients who received piperacillin/tazobactam. Treatment outcomes, including rates of in-hospital mortality, pneumonia-related readmission, and all-cause mortality within 6 months after discharge, were comparable between the two groups. In a subgroup analysis of data from patients who required tube feeding, the risk for in-hospital mortality was significantly higher among those who received cefepime (fully adjusted odds ratio, 1.43; 95% confidence interval, 1.04-1.97; p = 0.042). Treatment outcomes did not differ between patients who received cefepime and those who received piperacillin/tazobactam treatment, but among patients who were at risk for aspiration, such as those receiving tube feeding, those who received piperacillin/tazobactam had lower rates of in-hospital mortality.

Cefepime-Induced Neurotoxicity or Nonconvulsive Status Epilepticus (NCSE): A Controversy Revisited

Neurotoxicity is a well-known side effect of cefepime among patients commonly present with altered mental status and typical electroencephalogram (EEG) findings of generalized periodic discharges (GPDs). Some practitioners consider this pattern as encephalopathy and often treat it with the withdrawal of cefepime only, while others are at times concerned with non-convulsive status epilepticus (NCSE) and treat it with antiseizure medications (ASMs) in addition to the withdrawal of cefepime to accelerate the recovery. We present a case series of two patients who developed cefepime-induced altered mental status and EEG findings of GPDs at a rate of 2-2.5 Hz concerning for the ictal-interictal continuum (IIC). Both cases were treated as possible NCSE with ASMs in addition to the withdrawal of cefepime, resulting in different clinical outcomes. The first case showed clinical and EEG improvement shortly after the administration of parenteral benzodiazepines and ASMs. The other case showed electrographic improvement but did not show significant improvement in mentation, and the patient died eventually.

Machine-Learning Model for Prediction of Cefepime Susceptibility in Escherichia coli from Whole-Genome Sequencing Data

The declining cost of performing bacterial whole-genome sequencing (WGS) coupled with the availability of large libraries of sequence data for well-characterized isolates have enabled the application of machine-learning (ML) methods to the development of nonlinear sequence-based predictive models. We tested the ML-based model developed by Next Gen Diagnostics for prediction of cefepime phenotypic susceptibility results in Escherichia coli. A cohort of 100 isolates of E. coli recovered from urine (n = 77) and blood (n = 23) cultures were used. The cefepime MIC was determined in triplicate by reference broth microdilution and classified as susceptible (MIC of ≤2 μg/mL) or not susceptible (MIC of ≥4 μg/mL) using the 2022 Clinical and Laboratory Standards Institute breakpoints. Five isolates generated both susceptible and not susceptible MIC results, yielding categorical agreement of 95% for the reference method to itself. Categorical agreement of ML to MIC interpretations was 97%, with 2 very major (false, susceptible) and 1 major (false, not susceptible) errors. One very major error occurred for an isolate with blaCTX-M-27 (MIC mode, ≥32 μg/mL) and one for an isolate with blaTEM-34 for which the MIC cefepime mode was 4 μg/mL. One major error was for an isolate with blaCTX-M-27 but with a MIC mode of 2 μg/mL. These preliminary data demonstrated performance of ML for a clinically important antimicrobial-species pair at a caliber similar to phenotypic methods, encouraging wider development of sequence-based susceptibility prediction and its validation and use in clinical practice.

In Vitro Activity of Two Cefepime-Based Novel Combinations, Cefepime/Taniborbactam and Cefepime/Zidebactam, against Carbapenemase-Expressing Enterobacterales Collected in India

In recent times, discovery efforts for novel antibiotics have mostly targeted carbapenemase-producing Gram-negative organisms. Two different combination approaches are pertinent: β-lactam-β-lactamase inhibitor (BL/BLI) or β-lactam-β-lactam enhancer (BL/BLE). Cefepime combined with a BLI, taniborbactam, or with a BLE, zidebactam, has been shown to be promising. In this study, we determined the in vitro activity of both these agents along with comparators against multicentric carbapenemase-producing Enterobacterales (CPE). Nonduplicate CPE isolates of Escherichia coli (n = 270) and Klebsiella pneumoniae (n = 300), collected from nine different tertiary-care hospitals across India during 2019 to 2021, were included in the study. Carbapenemases in these isolates were detected by PCR. E. coli isolates were also screened for the presence of the 4-amino-acid insert in penicillin binding protein 3 (PBP3). MICs were determined by reference broth microdilution. Higher MICs of cefepime/taniborbactam (>8 mg/L) were linked to NDM, both in K. pneumoniae and in E. coli. In particular, such higher MICs were observed in 88 to 90% of E. coli isolates producing NDM and OXA-48-like or NDM alone. On the other hand, OXA-48-like-producing E. coli or K. pneumoniae isolates were nearly 100% susceptible to cefepime/taniborbactam. Regardless of the carbapenemase types and the pathogens, cefepime/zidebactam showed potent activity (>99% inhibited at ≤8 mg/L). It seems that the 4-amino-acid insert in PBP3 (present universally in the study E. coli isolates) along with NDM adversely impact the activity of cefepime/taniborbactam. Thus, the limitations of the BL/BLI approach in tackling the complex interplay of enzymatic and nonenzymatic resistance mechanisms were better revealed in whole-cell studies where the activity observed was a net effect of β-lactamase inhibition, cellular uptake, and target affinity of the combination. IMPORTANCE The study revealed the differential ability of cefepime/taniborbactam and cefepime/zidebactam in tackling carbapenemase-producing Indian clinical isolates that also harbored additional mechanisms of resistance. NDM-expressing E. coli with 4-amino-acid insert in PBP3 are predominately resistant to cefepime/taniborbactam, while the β-lactam enhancer mechanism-based cefepime/zidebactam showed consistent activity against single- or dual-carbapenemase-producing isolates including E. coli with PBP3 inserts.

A Case-Report of Drug-Induced Mixed Liver Injury Resulting From Cefepime Exposure

A 99-year-old African-American male presented to the hospital with severe sepsis secondary to a urinary tract infection. Upon initial presentation he was tachycardic, hypotensive and had leukocytosis. While he had signs of acute kidney injury, no signs of acute liver injury were present with his alanine transferase (ALT) and amino transferase (AST) levels measuring at 22 and 44 U/L, respectively. During the treatment course the patient began to show signs of clinical improvement. Despite this, his ALT and AST began to increase on day 2 of treatment and reached their peak of 210 and 239 U/L on day 4. Cefepime-induced liver injury was suspected and cefepime was discontinued. Upon cefepime discontinuation, liver enzymes downtrended and gradually returned to normal. No other likely medication causes of liver injury could be identified and alternative medical causes were ruled out. The lack of an alternative cause and the temporal relationship of cefepime use to hepatic dysfunction support the diagnosis of cefepime-induced liver injury. The patient's Roussel Uclaf Causality Assessment Methods score was 7, indicating this was a possible case of cefepime-induced liver injury, and the Naranjo Nomogram score was 5 indicating this was a probable case of cefepime-induced liver injury. While cefepime-induced liver injury is rare, clinicians should be cognizant of the potential for this adverse effect if liver enzyme elevation is detected during cefepime therapy and other common causes have been ruled out.

Cefepime Dosing in a Critically Ill Neonate Receiving Continuous Renal Replacement Therapy With the Cardio-Renal Pediatric Dialysis Emergency Machine (CARPEDIEM)

We report on a former 27-week gestational age infant who was placed on the Cardio-Renal Pediatric Dialysis Emergency Machine (CARPEDIEM) at 4 months post-menstrual age while receiving cefepime treatment for an Enterobacter cloacae bacteremia and persistent peritonitis secondary to an infected peritoneal dialysis catheter. Using therapeutic drug monitoring while assessing the clearance of cefepime on continuous renal replacement therapy (CRRT), we were able to successfully treat this patient's infection while also minimizing the risk of side effects from this medication. Current literature supports dosing in adult patients on all modalities of CRRT with effluent flow rates of 20 to 25 mL/kg/hr; however, pharmacokinetic data on cefepime dosing in pediatric CRRT are scant. This case report describes the successful dosing strategy used for this patient while on various rates of continuous veno-venous hemodialysis with CARPEDIEM. Therapeutic drug monitoring of cefepime should be considered in critically ill pediatric patients on CARPEDIEM receiving CRRT.

Cefepime-Induced Neutropenia: A Case Report and Literature Review

Cefepime is a fourth-generation cephalosporin utilized in treatment of multiple Gram-negative and -positive infections. The current report presents a case of 50-year-old man admitted with epidural abscess who developed neutropenia after prolonged use of cefepime. The neutropenia developed after 24 days of cefepime treatment and resolved 4 days after cessation of cefepime. Assessment of the patient's profile indicated no other possible cause for neutropenia. A literature review was done, and is presented herein to compare and identify the pattern of cefepime-induced neutropenia in 15 patients. The data presented in this article highlight that despite its rarity, cefepime-induced neutropenia should be considered by clinicians when planning a prolonged course of cefepime.

Use of therapeutic drug monitoring to characterize cefepime-related neurotoxicity

STUDY OBJECTIVES

Data evaluating cefepime thresholds associated with neurotoxicity remain limited. The objectives of this study were to evaluate the incidence of cefepime-related neurotoxicity (CRN) in patients with plasma cefepime concentrations, assess the relationship between cefepime exposure and CRN, investigate clinical factors associated with CRN, and describe electroencephalogram (EEG) abnormalities in CRN.

DESIGN

This was a retrospective study of adult inpatients admitted between 2016 and 2018 who received cefepime therapeutic drug monitoring (TDM). Potential CRN cases were identified utilizing a standard definition. The primary outcomes of the study were to determine the incidence of CRN and evaluate the relationship between cefepime trough concentrations, the average daily AUC, and neurotoxicity. Bayesian posteriors were generated for each patient using a cefepime pharmacokinetic (PK) model, and the mean daily area under the concentration-time curve (AUC) was calculated. Multiple regression was performed to assess the association between CRN, cefepime PK, and clinical predictors of neurotoxicity.

MAIN RESULTS

Four hundred eighty-one patients with 503 hospital encounters received cefepime TDM and were included in the analysis. The incidence of CRN was 4.4% (22/503). Patients with CRN had a higher incidence of renal dysfunction, hypertension, and diabetes mellitus compared to patients without CRN (non-NT). The mean cefepime trough concentration was significantly greater in the CRN patients than in the non-NT group (61.8 ± 33.7 vs. 30 ± 27.7 mg/L, respectively, p = 0.0002). Cefepime trough concentration and renal dysfunction were independently associated with increased risk of CRN in the adjusted multiple regression model. Moderate generalized slowing of the background rhythm was the most common EEG pattern associated with CRN. Delaying cefepime TDM greater than 72 h after the initiation of cefepime was associated with a 3-fold increased risk of CRN.

CONCLUSION

Cefepime should be used cautiously in hospitalized patients with renal dysfunction due to the risk of neurotoxicity. Dose optimization utilizing TDM early in cefepime treatment may minimize adverse effects and improve patient safety.

Continuous Infusion of High Doses of Cefepime in Intensive Care Unit: Assessment of Steady-State Plasma Level and Incidence on Neurotoxicity

Continuous infusion (CI) with high doses of cefepime is recommended in the empirical antimicrobial regimen of critically ill patients with suspected Gram-negative sepsis. This study aimed to determine factors associated with cefepime overdosing and the incidence of cefepime-induced neurotoxicity (CIN) in these patients. We performed a retrospective study including all patients receiving cefepime treatment between January 2019 and May 2022. The plasma level of cefepime defining overdosing was over 35 mg/L. Neurotoxicity was defined according to strict criteria and correlated with concomitant steady-state concentration of cefepime. Seventy-eight courses of cefepime treatment were analyzed. The mean cefepime plasma level at steady state was 59.8 ± 29.3 mg/L, and overdosing occurred in 80% of patients. Renal failure and a daily dose > 5 g were independently associated with overdosing. CIN was present in 30% of patients. In multivariate analysis, factors associated with CIN were chronic renal failure and a cefepime plasma concentration ≥ 60 mg/L. CIN was not associated with mortality. Overdosing is frequent in patients receiving high doses of cefepime by CI. Steady-state levels are higher than targeted therapeutic pharmacokinetic/pharmacodynamic objectives. The risk of CIN is important when the plasma concentration is ≥60 mg/L.

Quantifying Gram-Negative Resistance to Empiric Treatment After Repeat ExpoSure To AntimicRobial Therapy (RESTART)

Background

Antibiotic exposure is a primary predictor of subsequent antibiotic resistance; however, development of cross-resistance between antibiotic classes is also observed. The impact of changing to a different antibiotic from that of previous exposure is not established.

Methods

This was a retrospective, single-center cohort study of hospitalized adult patients previously exposed to an antipseudomonal β-lactam (APBL) for at least 48 hours in the 90 days prior to the index infection with a gram-negative bloodstream or respiratory infection. Susceptibility rates to empiric therapy were compared between patients receiving the same (repeat group) versus a different antibiotic from prior exposure (change group).

Results

A total of 197 patients were included (n = 94 [repeat group] and n = 103 [change group]). Pathogen susceptibility to empiric therapy was higher in the repeat group compared to the change group (76.6% vs 60.2%; P = .014). After multivariable logistic regression, repeat APBL was associated with an increased likelihood of pathogen susceptibility (adjusted odds ratio, 2.513; P = .012). In contrast, there was no difference in susceptibility rates between the repeat group and the subgroup of change patients who received an empiric APBL (76.6% vs 78.5%; P = .900). Longer APBL exposure duration (P = .012) and chronic kidney disease (P = .002) were associated with higher nonsusceptibility to the exposure APBL. In-hospital mortality was not significantly different between the repeat and change groups (18.1% vs 23.3%; P = .368).

Conclusions

The common practice of changing to a different APBL from that of recent exposure may not be warranted.

Cefepime Extraction by Extracorporeal Life Support Circuits

Extracorporeal life support (ECLS) devices are lifesaving for critically ill patients with multi-organ dysfunction. Despite this, patients supported with ECLS are at high risk for ECLS-related complications, including nosocomial infections, and mortality rates are high in this patient population. The high mortality rates are suspected to be, in part, a result of significantly altered drug disposition by the ECLS circuit, resulting in suboptimal antimicrobial dosing. Cefepime is commonly used in critically ill patients with serious infections. Cefepime dosing is not routinely guided by therapeutic drug monitoring and treatment success is dependent upon the percentage of time of the dosing interval that the drug concentration remains above the minimum inhibitory concentration of the organism. This ex vivo study measured the extraction of cefepime by continuous renal replacement therapy (CRRT) and extracorporeal membrane oxygenation (ECMO) circuits. Cefepime was studied in four closed-loop CRRT circuit configurations and a single closed-loop ECMO circuit configuration. Circuits were primed with a physiologic human blood-plasma mixture and the drug was dosed to achieve therapeutic concentrations. Serial blood samples were collected over time and concentrations were quantified using validated assays. In ex vivo CRRT experiments, cefepime was rapidly cleared by dialysis, hemofiltration, and hemodiafiltration, with greater than 96% cefepime eliminated from the circuit by 2 hours. In the ECMO circuits, the mean recovery of cefepime was similar in both circuit and standard control. Mean (standard deviation) recovery of cefepime in the ECMO circuits (n = 6) was 39.2% (8.0) at 24 hours. Mean recovery in the standard control (n = 3) at 24 hours was 52.2% (1.5). Cefepime is rapidly cleared by dialysis, hemofiltration, and hemodiafiltration in the CRRT circuit but minimally adsorbed by either the CRRT or ECMO circuits. Dosing adjustments are needed for patients supported with CRRT.

Retrospective Cohort Study of the Incidence of Acute Kidney Injury with Vancomycin Area under the Curve-Based Dosing with Concomitant Piperacillin-Tazobactam Compared to Meropenem or Cefepime

Acute kidney injury (AKI) is a complication associated with vancomycin. Previous studies demonstrated that the combination of vancomycin and piperacillin-tazobactam increases the risk of AKI compared to vancomycin with meropenem or cefepime. These studies did not utilize area under the curve (AUC)-based dosing, which reduces vancomycin exposure and may decrease nephrotoxicity compared with trough-based dosing. This study evaluated the incidence of AKI in patients receiving AUC-dosed vancomycin with either concomitant piperacillin-tazobactam (VPT) or meropenem or cefepime (VMC). This retrospective cohort study included patients admitted to Sentara Norfolk General Hospital between October 2019 and September 2020 who received AUC-dosed vancomycin and concomitant piperacillin-tazobactam, meropenem, or cefepime for at least 48 h. The primary outcome was the incidence of AKI during treatment or within 24 h of discontinuation. A total of 435 patients (VPT, n = 331; VMC, n = 104) who received a median duration of 4 days of treatment were included. The incidence of AKI was significantly higher with VPT than with VMC (13.6% versus 4.8% [P = 0.014]). Multivariable analysis showed VPT to be an independent risk factor for the development of AKI (odds ratio [OR], 3.00 [95% confidence interval {CI}, 1.15 to 7.76]). VPT was associated with more frequent AKI than VMC, even with the relatively short courses of antimicrobial therapy administered in this population. In comparison with the precedent in the literature for trough-based vancomycin dosing, our results suggest that the use of AUC-based vancomycin dosing in combination with piperacillin-tazobactam, meropenem, or cefepime may result in a lower overall incidence of AKI.

Safety and Pharmacokinetics of Taniborbactam (VNRX-5133) with Cefepime in Subjects with Various Degrees of Renal Impairment

Taniborbactam, an investigational β-lactamase inhibitor that is active against both serine- and metallo-β-lactamases, is being developed in combination with cefepime to treat serious infections caused by multidrug-resistant Gram-negative bacteria. Anticipating the use of cefepime-taniborbactam in patients with impaired renal function, an open-label, single-dose clinical study was performed to examine the pharmacokinetics of both drugs in subjects with various degrees of renal function. Hemodialysis-dependent subjects were also studied to examine the amounts of cefepime and taniborbactam dialyzed. Single intravenous infusions of 2 g cefepime and 0.5 g taniborbactam coadministered over 2 h were examined, with hemodialysis-dependent subjects receiving doses both on- and off-dialysis. No subjects experienced serious adverse events or discontinued treatment due to adverse events. The majority of adverse events observed were mild in severity, and there were no trends in the safety of cefepime-taniborbactam related to declining renal function or the timing of hemodialysis. Clinically significant and similar decreases in drug clearance with declining renal function were observed for both cefepime and taniborbactam. The respective decreases in geometric mean clearance for subjects with mild, moderate, and severe renal impairment compared to subjects with normal renal function were 18%, 63%, and 78% for cefepime and 15%, 63%, and 81% for taniborbactam, respectively. Decreases in clearance were similar for both drugs and were shown to be proportional to decreases in renal function. Both cefepime and taniborbactam were dialyzable, with similar amounts removed during 4 h of hemodialysis. This study is registered at ClinicalTrials.gov as NCT03690362.

Development and validation of an LC-ESI-QTOF-MS method to measure cefepime in the plasma and peritoneal fluid of rats using microdialysis: application in a pilot pharmacokinetic study

Cefepime (CEF) is a cephalosporin and can be administered in secondary peritonitis together with metronidazole to treat sepsis. This study aimed to develop and validate a method of LC-ESI-QTOF-MS for the quantification of cefepime in the plasma and peritoneal microdialysate of healthy Wistar rats. Chromatographic separation was performed using a CLC-ODS C₁₈ column (250 mm x 4.6 mm), a C₁₈ pre-column (4 mm, 5 μm) and isocratic elution. Gallic acid was used as the internal standard (IS). The mobile phase consisted of (A) ultrapure water (pH adjusted to 3.5) and (B) acetonitrile (80:20, v/v) at 0.8 mL/min. Quantification was performed using a mass spectrometer with electrospray ionization in positive mode to monitor ions with m/z 481.1322 (CEF) and m/z 171.0288 (IS). The method was validated for selectivity, precision, accuracy, linearity, stability, lower limit of quantification, carryover, recovery, and matrix effect. Calibration was done in the range of 1-40 μg/mL and 1-100 μg/mL for the peritoneal microdialysate and plasma, respectively. Plasma extraction recovery ranged from 93.9% to 99.9%. The technique was validated and successfully applied in a pilot pharmacokinetic study for estimating the free concentration of CEF in the peritoneal microdialysate of rats for the first time.

New Life of an Old Drug: Caffeine as a Modulator of Antibacterial Activity of Commonly Used Antibiotics

With the rapid and continuous emergence of antimicrobial resistance, bacterial infections became a significant global healthcare concern. One of the proposed strategies to combat multidrug-resistant pathogens is to use additional compounds, such as natural biologically active substances, as adjuvants for existing antibiotics. In this study, we investigated the potential of caffeine, the widely consumed alkaloid, to modulate the antibacterial effects of antibiotics commonly used in clinical practice. We used disc diffusion assay to evaluate the effects of caffeine on 40 antibiotics in two Staphylococcus aureus strains (methicillin-resistant and methicillin-sensitive). Based on the results of this step, we selected five antibiotics for which the greatest caffeine-induced improvements in antibacterial activity were observed, and further analyzed their interactions with caffeine using a checkerboard approach. Caffeine at concentrations of 250 µg/mL or higher halved the MIC values of ticarcillin, cefepime, gentamycin, azithromycin, and novobiocin for all gram-negative species investigated (Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii). At the highest caffeine concentrations tested (up to 16 mg/mL), decreases in MIC values were 8- to 16-fold. The obtained results prove that caffeine modulates the activity of structurally diverse antibiotics, with the most promising synergistic effects observed for cefepime and azithromycin toward gram-negative pathogens.

Cefepime Induced Neurotoxicity Following A Regimen Dose-Adjusted for Renal Function: Case Report and Review of the Literature

Introduction: Cefepime induced neurotoxicity (CIN) is commonly associated with renal dysfunction, however CIN can occur in patients with normal renal function or renally dose-adjusted regimens. Few reports of this kind have obtained cefepime concentrations to assist in diagnosis. Patient Case: A 42-year old female with a complex past medical history was transferred to our facility with chief complaint of worsening shock and respiratory failure, and the patient was also noted to be hypernatremic, experiencing diabetic ketoacidosis (DKA), and acute kidney injury (AKI). Her DKA resolved and hypernatremia and AKI began to improve. As a result, cefepime was dose-adjusted for renal function estimated by the Cockcroft-Gault (CG) equation. Her hospital course was complicated by persistent altered mental status (AMS), preventing extubation. Cefepime was discontinued due to concern for CIN, and a concentration was obtained 13-hours after the last dose which was elevated at 49 µg/mL. Two days following cefepime discontinuation, the patient's mental status improved allowing for successful extubation. The patient remained stable and was discharged to an acute care floor and then ultimately back to home. Conclusion: CIN should be part of a wider differential diagnosis for patients experiencing encephalopathy, and inaccurate renal function estimation may be a risk factor for developing CIN. Furthermore, therapeutic drug monitoring (TDM) may serve as an important clinical tool in diagnosing and managing CIN.

Evaluation of the safety of cefepime prolonged infusions in pediatric patients with cystic fibrosis

OBJECTIVE

Pediatric cystic fibrosis (CF) patients possess unique pharmacokinetics and may benefit from prolonged beta-lactam infusions to optimize pharmacodynamics. This study compared adverse drug event (ADE) rates with cefepime prolonged (PI) and standard infusions (SI).

METHODS

This retrospective study included pediatric patients treated with cefepime for CF exacerbations between 2009 and 2019. One encounter per patient was analyzed with prioritization of SI encounters given sample size limitations. Baseline lab abnormalities, seizure disorders, and bleeding were exclusion criteria. The primary outcome was a composite safety endpoint (acute kidney injury [AKI], hepatotoxicity, hematologic toxicity, neurotoxicity, and hypersensitivity).

RESULTS

Of 188 patients, 135 received PI and 53 received SI. Baseline characteristics were similar between groups. More PI patients used CF transmembrane conductance regulator (CFTR) modulators (25% vs. 0%, p < 0.01) or had antibiotic allergies (62% vs. 38%, p = 0.02). Difference in rates of composite safety endpoint was not statistically significant between PI and SI (21 [15.6%] vs. 6 [11.3%] p = 0.46) nor was incidence of AKI (16 [11.8%] vs. 6 [11.3%], p = 0.92). Other ADEs were rarely observed. Length of stay (12.2 vs. 10.1 days, p = 0.06), change in discharge ppFEV1 from admission (13 vs. 12, p = 0.91) or from baseline (-4 vs. -6.5, p = 0.33), and time to next exacerbation (249.7 vs. 192.5 days, p = 0.93) were similar.

CONCLUSIONS

No difference in risk of ADEs including AKI was seen with cefepime PI in pediatric CF patients. Clinical outcomes were not significantly different between groups, but sample size may have limited comparison. PI cefepime may be considered in pediatric CF patients to optimize pharmacodynamics.

Retrospective Cohort Study of Clinical Efficacy and Safety of Cefozopran for Treating Febrile Neutropenia during Chemotherapy in Patients with Lung Cancer

Febrile neutropenia (FN) is a serious side effect in patients undergoing cancer chemotherapy and frequently proves fatal. Since infection control is crucial in the management of FN, the antimicrobial agent cefozopran (CZOP) has been recommended but not approved for routine use in clinical care of FN in Japan. However, few studies of CZOP in the management of FN have used a thrice daily dose schedule. The aim of this study was to retrospectively compare the efficacy and safety of CZOP at a dose of 1 g three times daily to those of cefepime (CFPM) in the treatment of FN in our lung cancer patients. The response rates of the CZOP and CFPM groups were 89.5% (17/19 cases) and 83.0% (39/47 cases), respectively, with no significant difference between the two groups. The median duration of antimicrobial treatment was 6 days (4-10 days) in the CZOP group and 7 days (3-13 days) in the CFPM group, with no significant difference between groups. The incidence rates of adverse events were 21.1% (4/19 cases) in the CZOP group and 19.1% (9/47 cases) in the CFPM group. No adverse events of Grade 3 or higher were observed in either group. The findings of the present study suggest that CZOP administration at a dose of 1 g three times per day as an antimicrobial treatment alternative against FN.

Cefepime-induced Neurotoxicity: A Retrospective Cohort Study in a South-Indian Tertiary Healthcare Facility

BACKGROUND

Cefepime is a fourth-generation cephalosporin with a broad spectrum coverage and anti-pseudomonal activity. The safety profile of cefepime was relatively favourable until neurotoxicity was first reported in 1999. Despite cefepime-induced neurotoxicity (CIN), it continues to be a principal part of parenteral treatment for various infections.

OBJECTIVE

The study aimed to determine the incidence and risk factors for CIN compared to other antibiotics.

METHODS

A retrospective cohort study was conducted involving 738 patients over eight months in Kasturba Medical College and Hospital, Manipal, India. Patients with cefepime were selected as study cohort (SC; n= 496), and other antibiotics were included in the reference cohort (RC; n=242).

RESULTS

The results showed that 53 (10.7%) patients developed neurotoxicity in the SC, whereas 12 (5%) patients in the RC. A significant association was found between neurotoxicity and cefepime use (X² =6.641; p=0.01). SC has a 2.29 times increased risk of neurotoxicity than RC (OR: 2.29; 95% CI: 1.2-4.38). Risk estimation showed that renal failure patients had a 5.5 times higher risk for CIN than non-renal failure patients (OR: 5.5; 95% CI: 2.98 - 10.17). CIN symptoms were disorientation (38.5%), loss of consciousness (23.1%), drowsiness (18.5%), etc. The calculated number needed to harm (NNH) for cefepime was 17.2.

CONCLUSION

The study found a higher incidence of CIN compared to other antibiotics-induced neurotoxicity and a harmful association between cefepime use and CIN development. Besides, renal failure is a risk factor for CIN. Therefore, the study warrants the use of cefepime, where no other alternatives are available.

Pediatric drug utilization evaluation of cefepime and piperacillin/tazobactam

BACKGROUND

Drug utilization evaluation (DUE) is a systematic, criteria-based assessment of medicine that aims to optimize the appropriateness of antibiotic prescription. This study aimed to evaluate the performance of the DUE on prescriptions of two commonly used antibiotics in a pediatric population, cefepime and piperacillin/tazobactam, in a tertiary care hospital.

METHODS

This quasi-experimental study was conducted at the Department of Pediatrics, Ramathibodi Hospital, between March 2020 and August 2021. All hospitalized children aged 1 month to 20 years who received at least one dose of cefepime or piperacillin/tazobactam were enrolled. Before implementing the DUE, cefepime and piperacillin/tazobactam prescriptions were retrospectively evaluated using the DUE criteria. During the 6 month DUE implementation period, physicians voluntarily chose to use DUE to assess the prescriptions' appropriateness. Demographic data, antibiotic use, and clinical data were recorded.

RESULTS

There were 304 prescriptions of cefepime and piperacillin/tazobactam, with 108 empirical prescriptions (72 patients) in the DUE group and 158 prescriptions (138 patients) in the non-DUE group. The appropriateness of empirical prescriptions of cefepime and piperacillin/tazobactam was significantly higher in the DUE group (93.5% vs. 83.5%; P = 0.003). Drug utilization evaluation was significantly associated with appropriate empirical prescriptions (adjusted OR 5.32: 95% CI 1.80-15.73; P = 0.003). Prescriptions in critical care wards and urinary tract infections (UTIs) were associated with not fulfilling the DUE criteria for appropriateness.

CONCLUSIONS

Drug utilization evaluation could improve the appropriateness of empirical use of cefepime and piperacillin/tazobactam in pediatric patients. Patients in critical care units and with UTIs appeared to be associated with inappropriate empirical treatment.

A Genome-Scale Antibiotic Screen in Serratia marcescens Identifies YdgH as a Conserved Modifier of Cephalosporin and Detergent Susceptibility

Serratia marcescens, a member of the order Enterobacterales, is adept at colonizing health care environments and is an important cause of invasive infections. Antibiotic resistance is a daunting problem in S. marcescens because, in addition to plasmid-mediated mechanisms, most isolates have considerable intrinsic resistance to multiple antibiotic classes. To discover endogenous modifiers of antibiotic susceptibility in S. marcescens, a high-density transposon insertion library was subjected to sub-MICs of two cephalosporins, cefoxitin, and cefepime, as well as the fluoroquinolone ciprofloxacin. Comparisons of transposon insertion abundance before and after antibiotic exposure identified hundreds of potential modifiers of susceptibility to these agents. Using single-gene deletions, we validated several candidate modifiers of cefoxitin susceptibility and chose ydgH, a gene of unknown function, for further characterization. In addition to cefoxitin, deletion of ydgH in S. marcescens resulted in decreased susceptibility to multiple third-generation cephalosporins and, in contrast, to increased susceptibility to both cationic and anionic detergents. YdgH is highly conserved throughout the Enterobacterales, and we observed similar phenotypes in Escherichia coli O157:H7 and Enterobacter cloacae mutants. YdgH is predicted to localize to the periplasm, and we speculate that it may be involved there in cell envelope homeostasis. Collectively, our findings provide insight into chromosomal mediators of antibiotic resistance in S. marcescens and will serve as a resource for further investigations of this important pathogen.

Combination therapy with levofloxacin and cefepime to treat severe respiratory infection due to Aeromonas caviae after a near-drowning accident in river water

Background

Aeromonas spp. are gram-negative anaerobic rods that are mainly found in water. Respiratory infections due to Aeromonas sp. are rare but have a high mortality rate.

Case presentation

A 43-year-old man fell into a river following an automobile accident and almost drowned. He developed a severe respiratory infection and acute respiratory distress syndrome. Ampicillin/sulbactam was given; however, Aeromonas caviae was detected in his blood culture. Despite treatment with levofloxacin, to which A. caviae was susceptible, his condition failed to improve. However, with additional treatment with cefepime, his blood culture results were negative, and his condition improved.

Conclusion

When a patient develops a respiratory infection after aspiration of river water, empiric antimicrobial therapy should be given as soon as possible to manage the risk of Aeromonas sp. infection.

Effect of sub-inhibitory concentrations of cefepime on biofilm formation by Pseudomonas aeruginosa

This study investigated the effect of cefepime at sub-minimum inhibitory concentrations (sub-MICs) on in vitro biofilm formation (BF) by clinical isolates of Pseudomonas aeruginosa. The effect of cefepime at sub-MIC levels (½-¹/₂₅₆ MIC) on in vitro BF by six clinical isolates of P. aeruginosa was phenotypically assessed following 24 and 48 h of challenge using the tissue culture plate (TCP) assay. Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to observe the change in expression of three biofilm-related genes, namely, a protease-encoding gene (lasA), fimbrial protein-encoding gene (cupA1), and alginate-encoding gene (algC), in a weak biofilm-producing strain of P. aeruginosa following 24 and 48 h of challenge with sub-MICs of cefepime. The BF morphology in response to cefepime was imaged using scanning electron microscopy (SEM). The TCP assay showed strain-, time-, and concentration-dependent changes in in vitro BF in P. aeruginosa following challenge with sub-MICs of cefepime, with a profound increase in strains with inherently no or weak biofilm-producing ability. RT-PCR revealed time-dependent upregulation in the expression of the investigated genes following challenge with ½ and ¼ MIC levels, as confirmed by SEM. Cefepime at sub-MICs could upregulate the expression of BF-related genes and enhance BF by P. aeruginosa clinical isolates.

Comparison of Ceftriaxone and Antipseudomonal β-Lactam Antibiotics Utilized for Potential AmpC β-Lactamase-Producing Organisms

Background: Induction of antibiotic resistance is associated with increased morbidity and mortality in AmpC β-lactamase producing Enterobacteriaceae. The use of ceftriaxone is controversial for treatment of these organisms due to concerns for inducible resistance. This study was designed to compare treatment failure rates between ceftriaxone and antipseudomonal β-lactam antibiotics when used as definitive therapy for organisms most commonly associated with chromosomal AmpC β-lactamase production. Methods: A retrospective, single-center cohort study was performed enrolling patients hospitalized with monomicrobial Enterobacter, Citrobacter, or Serratia spp. infections. The primary objective compared proportion of treatment failure between groups. All patients received either ceftriaxone or an antipseudomonal β-lactam alone within 24 hours of culture finalization, and with a duration of at least 72 hours for definitive treatment. Treatment failure was defined as either clinical failure (abnormal white blood cell count or temperature on day 7 or 14 post-antibiotics) or microbiologic failure (regrowth of the same organism at same site within 14 or 21 days). Results: Of 192 total patients, treatment failure was observed in 24/71 patients (34%) receiving ceftriaxone and in 42/121 patients (35%) receiving antipseudomonal β-lactam (P = .98). No difference was observed between clinical or microbiologic failure rates between groups. The ceftriaxone group had significantly more patients undergoing treatment for urinary tract infections (51% vs 17%, P < .001), but treatment failure rates remained similar between groups when comparing infections of all other sources. Conclusion: Ceftriaxone has comparable treatment failure rates to antipseudomonal β-lactams for susceptible Enterobacteriaceae infections and may be considered as a therapeutic option. Further, prospective research is needed to validate optimal dosing and application in all sites of infection.

Essential Oil and Hydrophilic Antibiotic Co-Encapsulation in Multiple Lipid Nanoparticles: Proof of Concept and In Vitro Activity against Pseudomonas aeruginosa

In the worldwide context of an impending emergence of multidrug-resistant bacteria, this research combined the advantages of multiple lipid nanoparticles (MLNs) and the promising therapeutic use of essential oils (EOs) as a strategy to fight the antibiotic resistance of three Pseudomonas aeruginosa strains with different cefepime (FEP) resistance profiles. MLNs were prepared by ultrasonication using glyceryl trioleate (GTO) and glyceryl tristearate (GTS) as a liquid and a solid lipid, respectively. Rosemary EO (REO) was selected as the model EO. REO/FEP-loaded MLNs were characterized by their small size (~110 nm), important encapsulation efficiency, and high physical stability over time (60 days). An assessment of the antimicrobial activity was performed using antimicrobial susceptibility testing assays against selected P. aeruginosa strains. The assays showed a considerable increase in the antibacterial property of REO-loaded MLNs compared with the effect of crude EO, especially against P. aeruginosa ATCC 9027, in which the minimum inhibitory concentration (MIC) value decreased from 80 to 0.6 mg/mL upon encapsulation. Furthermore, the incorporation of FEP in MLNs stabilized the drug without affecting its antipseudomonal activity. Thus, the ability to co-encapsulate an essential oil and a hydrophilic antibiotic into MLN has been successfully proved, opening new possibilities for the treatment of serious antimicrobial infections.

Efficacy of Ceftazidime and Cefepime in the Management of COVID-19 Patients: Single Center Report from Egypt

The purpose of this study was to explore the value of using cefepime and ceftazidime in treating patients with COVID-19. A total of 370 (162 males) patients, with RT-PCR-confirmed cases of COVID-19, were included in the study. Out of them, 260 patients were treated with cefepime or ceftazidime, with the addition of steroids to the treatment. Patients were divided into three groups: Group 1: patients treated with cefepime (124 patients); Group 2: patients treated with ceftazidime (136 patients); Group 3 (control group): patients treated according to the WHO guidelines and the Egyptian COVID-19 management protocol (110 patients)/ Each group was classified into three age groups: 18–30, 31–60, and >60 years. The dose of either cefepime or ceftazidime was 1000 mg twice daily for five days. Eight milligrams of dexamethasone were used as the steroidal drug. Careful follow-ups for the patients were carried out. In vitro and in silico M^pro enzyme assays were performed to investigate the antiviral potential of both antibiotics. The mean recovery time for Group 1 was 12 days, for Group 2 was 13 days, and for Group 3 (control) was 19 days. No deaths were recorded, and all patients were recovered without any complications. For Group 1, the recovery time was 10, 12, and 16 days for the age groups 18–30, 30–60, and >60 years, respectively. For Group 2, the recovery time was 11, 13, and 15 days for the age groups 18–30, 30–60, and >60 years, respectively. For Group 3 (control), the recovery time was 15, 16, and 17 days for the age groups 18–30, 30–60, and >60 years, respectively. Both ceftazidime and cefepime showed very good inhibitory activity towards SARS CoV-2′s M^pro, with IC₅₀ values of 1.81 µM and 8.53 µM, respectively. In conclusion, ceftazidime and cefepime are efficient for the management of moderate and severe cases of COVID-19 due to their potential anti-SARS CoV-2 activity and low side effects, and, hence, the currently used complex multidrug treatment protocol can be replaced by the simpler one proposed in this study.

Cefepime-Induced Neurotoxicity

Cefepime is a common antibiotic used to treat various infections such as pneumonia, skin infections, and intra-abdominal infections due to its broad gram-positive and gram-negative spectrum. However, patients with acute kidney injury, end-stage renal disease, and renal transplantation are disproportionately at higher risk of developing complications from administration of cefepime, secondary to its predominant renal excretion. Current guidelines prescribe cefepime renal-dosing, dependent on the glomerular filtration rate, to prevent toxicity. This study presents a rare case where an acutely hospitalized patient undergoing chronic renal transplant rejection was administered renal-dose cefepime. Despite renal dosing, the patient developed neurotoxicity that manifested as delirium, inability to tolerate oral intake, and non-convulsive status epilepticus. Solely adjusting for renal dysfunction may be inadequate to prevent the accumulation of cefepime metabolites, which may present in an atypical manner in the patient. Such possibilities emphasize the need for continued evaluation of a patient’s mentation in case of cefepime administration. Cefepime-induced neurotoxicity incidences need to be evaluated and researched thoroughly.

Effects of piperacillin/tazobactam or cefepime on folinate dose in patients receiving high-dose methotrexate: A retrospective cohort study using Japanese administrative claims data

INTRODUCTION

Delayed methotrexate (MTX) clearance with the co-administration of piperacillin/tazobactam (PIPC/TAZ) has been reported. Penicillins have been associated with reduced MTX clearance but the evidence is limited. There are no cases described with cefepime but penicillins are listed as interacting with MTX. We aimed to reveal whether the co-administration of PIPC/TAZ or CFPM affects MTX clearance using data from an administrative database.

METHODS

We used data from the JMDC database, a large insurance claims database constructed in Japan. We included patients who were prescribed PIPC/TAZ or CFPM between days 1 and 3 in high-dose MTX (HD-MTX). We compared one co-administration episode (with PIPC/TAZ or CFPM) to one control episode (without), as a match-control study of two different episodes in the same patient. The primary outcomes were the duration and cumulative dose of leucovorin (LV) as a surrogate indicator of delayed MTX clearance.

RESULTS

Three patients who were co-administered PIPC/TAZ and 16 patients who were co-administered CFPM with HD-MTX were included. In the PIPC/TAZ group, the duration and the cumulative doses of LV were similar in co-administration and control episode (median 3.0 vs. 3.0 days and 288.0 vs. 219.0 mg). In the CFPM group, the duration and the cumulative doses of LV were not significantly different in co-administration and control episode (3.0 vs. 4.0 days and 169.5 vs. 258.0 mg).

CONCLUSIONS

Our findings revealed that PIPC/TAZ did not necessarily cause a delay in MTX clearance during HD-MTX therapy. Moreover, the co-administration of CFPM with HD-MTX did not affect MTX clearance.

In Vivo Pharmacodynamics of β-Lactams/Nacubactam against Carbapenem-Resistant and/or Carbapenemase-Producing Enterobacter cloacae and Klebsiella pneumoniae in Murine Pneumonia Model

Carbapenem-resistant Enterobacterales (CRE) and carbapenemase-producing Enterobacterales (CPE) have become global threats. CRE− and CPE− derived infections have been associated with high mortality due to limited treatment options. Nacubactam is a β-lactamase inhibitor and belongs to the new class of diazabicyclooctane. The agent has an in vitro antimicrobial activity against several classes of β-lactamase-producing Enterobacterales. This study evaluated antimicrobial activity of combination therapies including β-lactams (aztreonam, cefepime, and meropenem) and nacubactam against four Enterobacter cloacae and six Klebsiella pneumoniae isolates with murine pneumonia model. Based on changes in bacterial quantity, antimicrobial activities of some regimens were assessed. Combination therapies including β-lactams (aztreonam, cefepime, and meropenem) with nacubactam showed enhanced antimicrobial activity against CRE E. cloacae (−3.70 to −2.08 Δlog₁₀ CFU/lungs) and K. pneumoniae (−4.24 to 1.47 Δlog₁₀ CFU/lungs) with IMP-1, IMP-6, or KPC genes, compared with aztreonam, cefepime, meropenem, and nacubactam monotherapies. Most combination therapies showed bacteriostatic (−3.0 to 0 Δlog₁₀ CFU/lungs) to bactericidal (<−3.0 Δlog₁₀ CFU/lungs) activities against CRE isolates. This study revealed that combination regimens with β-lactams (aztreonam, cefepime, and meropenem) and nacubactam are preferable candidates to treat pneumonia due to CRE and CPE.

Evaluation Of Individualized Cefepime Dosing Strategy Using Population Pharmacokinetics

The use of population pharmacokinetics (PK) to optimize cefepime dosing could be an effective strategy, given the increasing prevalence of resistant gram-negative organisms. The objective of this study is to retrospectively compare dosing using PK approach (intervention) versus traditional dosing (control) for cefepime in patients with hospital-acquired pneumonia (HAP) or ventilator-associated pneumonia (VAP). Adult hospitalized patients with HAP or VAP receiving cefepime for ≥ 72 hours were screened first from August 2018 to January 2019 to be included in the intervention group, then screened during the pre-intervention period from August 2017 to July 2018 for the control group. Clinical improvement on day 7 of cefepime therapy was achieved in 72 % of the patients in the intervention group and 70 % of the patients in the control group (p = 0.8110). However, the clinical cure rate in the intervention group was higher than that of the control group (50 vs. 36.5 %, p = 0.0034). Cefepime dosing using population PK appears to be a novel, effective, and safe dosing strategy for patients with HAP or VAP. This article is protected by copyright. All rights reserved.