Are oral cefuroxime axetil, cefixime and cefditoren pivoxil adequate to treat uncomplicated acute pyelonephritis after switching from intravenous therapy? A pharmacokinetic/pharmacodynamic perspective

Oral Antibiotics for Bacteremia and Infective Endocarditis: Current Evidence and Future Perspectives

Bacteremia and endocarditis are two clinical syndromes that, for decades, were managed exclusively with parenteral antimicrobials, irrespective of a given patient's clinical condition, causative pathogen, or its antibiotic susceptibility profile. This clinical approach, however, was based on low-quality data and outdated expert opinions. When a patient's condition has improved, gastrointestinal absorption is not compromised, and an oral antibiotic regimen reaching adequate serum concentrations is available, a switch to oral antibacterials can be applied. Although available evidence has reduced the timing of the oral switch in bacteremia to three days/until clinical improvement, there are only scarce data regarding less than 10-day intravenous antibiotic therapy in endocarditis. Many standard or studied oral antimicrobial dosages are smaller than the approved doses for parenteral administration, which is a risk factor for treatment failure; in addition, the gastrointestinal barrier may affect drug bioavailability, especially when the causative pathogen has a minimum inhibitory concentration that is close to the susceptibility breakpoint. A considerable number of patients infected by such near-breakpoint strains may not be potential candidates for oral step-down therapy to non-highly bioavailable antibiotics like beta-lactams; different breakpoints should be determined for this setting. This review will focus on summarizing findings about pathogen-specific tailoring of oral step-down therapy for bacteremia and endocarditis, but will also present laboratory and clinical data about antibiotics such as beta-lactams, linezolid, and fosfomycin that should be studied more in order to elucidate their role and optimal dosage in this context.

A retrospective review of oral cephalosporins versus fluoroquinolones for the treatment of pyelonephritis

Background

The current Infectious Diseases Society of America guidelines for the treatment of acute uncomplicated pyelonephritis (AUP) advise caution when using oral beta-lactams due to concern for potentially inferior efficacy compared to fluoroquinolones (FQs) and trimethoprim-sulfamethoxazole; however, studies specifically evaluating the efficacy of oral cephalosporins (CPs) in AUP are limited.

Objective

To assess the safety and efficacy of oral CPs versus FQs for the treatment of AUP.

Design, setting and participants

This is a retrospective, chart review study conducted at a single-center, tertiary care hospital.

Measurements

The primary endpoint was treatment failure within 30 days, defined as a change in antibiotic or return to ED or clinic due to persistent symptoms. Secondary endpoints included adverse drug reactions (ADRs) and C. difficile infection (CDI) within 30 days.

Results

Of the 343 patients included in the study, treatment failure occurred in 54/338 (16.0%) patients and was similar between oral CPs and FQs (35/229 [15.3%] vs. 19/109 [17.4%]). A higher percentage of treatment failures were observed for third generation (3GC) and first generation (1GC) CPs compared to second generation CPs (2GC) (3GC: 15/65 [23.4%]; 1GC: 11/49 [22.4%]; 2GC: 9/115 [7.8%]). Documented ADRs were low (6/343 [1.7%]) and no cases of CDI were documented.

Conclusions

Oral CPs appear to be as safe and effective as FQs for the treatment of AUP. Fewer treatment failures were noted with 2GCs as compared to 3GCs and 1GCs.

Diabetes Mellitus Does Not Predict Discharge in Hospitalized Patients With Acute Pyelonephritis: A Study From Karachi, Pakistan

Introduction

The incidence of acute pyelonephritis (APN) in the diabetic population is comparatively higher and tends to be more complicated, with serious outcomes. Although complicated pyelonephritis (PN) needs hospital admission and intravenous antibiotics, the magnitude of hospital stay due to comorbidities is limited. This study's aim was to assess the impact of diabetes mellitus on length of hospital stay among patients with PN.

Methods

We did a retrospective data review of 520 randomly selected hospitalized patients of PN from March 2015 to December 2019 from a tertiary care center. Electronic medical records were used for identifying medical conditions through ICD-10 coding. Length of stay (LOS) was categorized as < five days and ≥ five days. Chi‐squared tests were used to compare categorical parameters. Logistic regression models were used for multivariate analyses.

Results

The study included 520 patients with PN; 194 (37.3 %) men and 326 (62.7%) women. Overall, there were 353 (67.8 %) and 167 (32.1 %) patients with LOS < five and ≥ five days respectively. Most of the patients had lower urinary tract symptoms (90%); among them, the majority (92%) were discharged within five days. Likewise, half of the patients had diabetes (51.2); among them, 53% were discharged after five days. Older age (OR:1.7, 95%CI: 1.1 - 2.6), upper urinary tract symptoms (OR:1.6, 95%CI: 1.1 - 2.4), lower urinary tract symptoms (OR:1.9, 95%CI: 1.1 - 3.5), creatinine greater than 1.5 mg/dl (OR:1.6, 95% CI: 1.1 - 2.4) was positively associated with LOS ≥ 5 days after adjusting for other covariates. Diabetes mellitus was not found to be associated with LOS ≥ 5 days (OR: 0.9, 95%CI: 0.8 - 1.5).

Conclusion

In patients with acute PN, diabetes mellitus is not independently associated with prolonged hospital stay beyond five days.

Evaluation of the adequacy of the antimicrobial therapy of invasive Haemophilus influenzae infections: A pharmacokinetic/pharmacodynamic perspective

INTRODUCTION

In Europe, non-typeable H. influenzae (NTHi) is the leading cause of invasive H. influenzae disease in adults and is associated with high mortality. The goal of this study was to determine whether current antimicrobial treatments for H. influenzae infection in Spain are suitable based on their probability of achieving pharmacokinetic/pharmacodynamic (PK/PD) targets.

METHODS

Pharmacokinetic parameters for the antibiotics studied (amoxicillin, amoxicillin/clavulanic acid, ampicillin, cefotaxime, ceftriaxone, imipenem and ciprofloxacin) and susceptibility data for H. influenzae were obtained from literature. A Monte Carlo simulation was used to estimate the probability of target attainment (PTA), defined as the probability that at least a specific value of a PK/PD index is achieved at a certain MIC, and the cumulative fraction of response (CFR), defined as the expected population PTA for a specific drug dose and a specific microorganism population.

RESULTS

Regardless of dosing regimen, all antibiotics yielded CFR values of 100% or nearly 100% for all strains, including BL+, BL- and BLNAR, except amoxicillin and ampicillin for BL+. Thus, if an infection is caused by BL+ strains, treatment with amoxicillin and ampicillin has a high probability of failure (CFR≤8%). For standard doses of amoxicillin, amoxicillin/clavulanic acid and imipenem, PK/PD breakpoints were consistent with EUCAST clinical breakpoints. For the other antimicrobials, PK/PD breakpoints were higher than EUCAST clinical breakpoints.

CONCLUSIONS

Our study confirms by PK/PD analysis that, with the antimicrobials used as empirical treatment of invasive H. influenzae disease, a high probability of therapeutic success can be expected.