Results from the Survey of Antibiotic Resistance (SOAR) 2014-16 in the Czech Republic

The Role of PK/PD Analysis in the Development and Evaluation of Antimicrobials

Pharmacokinetic/pharmacodynamic (PK/PD) analysis has proved to be very useful to establish rational dosage regimens of antimicrobial agents in human and veterinary medicine. Actually, PK/PD studies are included in the European Medicines Agency (EMA) guidelines for the evaluation of medicinal products. The PK/PD approach implies the use of in vitro, ex vivo, and in vivo models, as well as mathematical models to describe the relationship between the kinetics and the dynamic to determine the optimal dosing regimens of antimicrobials, but also to establish susceptibility breakpoints, and prevention of resistance. The final goal is to optimize therapy in order to maximize efficacy and minimize side effects and emergence of resistance. In this review, we revise the PK/PD principles and the models to investigate the relationship between the PK and the PD of antibiotics. Additionally, we highlight the outstanding role of the PK/PD analysis at different levels, from the development and evaluation of new antibiotics to the optimization of the dosage regimens of currently available drugs, both for human and animal use.

Clinical And Bacteriological Impact Of Clarithromycin In Streptococcal Pharyngitis: Findings From A Meta-Analysis Of Clinical Trials

Introduction

Among the bacterial upper respiratory tract infections (UTRIs), the most medically significant is pharyngitis due to Group A beta-hemolytic Streptococci (GABHS). A 2012 meta-review and a 2016 Cochrane systematic review reported favorably on the comparative efficacy and safety of clarithromycin in pediatric patients with URTIs and in adults with GABHS pharyngitis. In this paper, the evidence base for clarithromycin in patients with URTIs is augmented by a meta-analysis of comparative studies in GABHS pharyngitis.

Methods

A series of five outpatient trials of clarithromycin for the treatment of streptococcal pharyngitis from an internal database were subjected to meta-analysis. Active comparators comprised penicillin VK and erythromycin.

Results

Rates of clinical cure or improvement were very similar in all treatment assignments, but the rates of bacteriological cure were numerically higher with clarithromycin than with comparator antibiotics. Adverse events data indicated that clarithromycin was generally well tolerated in these studies, with a relatively low incidence of adverse events and few severe incidents.

Discussion

Though currently not advised as a first-line therapy for URTI in most guidelines, the results of the meta-analysis indicate that clarithromycin is nevertheless a valid, effective and largely well-tolerated treatment option for GABHS pharyngitis patients who cannot benefit from other agents.

Antimicrobial susceptibility of Gram-negative and Gram-positive bacteria collected from Eastern Europe: Results from the Tigecycline Evaluation and Surveillance Trial (T.E.S.T.), 2011-2016

OBJECTIVES

The Tigecycline Evaluation and Surveillance Trial (T.E.S.T.) is a global surveillance programme monitoring the in vitro activity of a panel of antimicrobial agents against clinically important bacterial isolates. Data for Gram-positive and Gram-negative isolates collected in Eastern Europe between 2011 and 2016 are presented here.

METHODS

Minimum inhibitory concentrations (MICs) were determined by the broth microdilution method using CLSI guidelines. Antimicrobial susceptibility was assessed using EUCAST breakpoints.

RESULTS

Nine Eastern European countries submitted 4289 isolates. Among Acinetobacter baumannii, resistance to levofloxacin, amikacin and meropenem was 77.5%, 63.4% and 62.2%, respectively. Multidrug resistance among A. baumannii was higher in 2015 than in previous years (44.1% in 2011 and 71.0% in 2015), decreasing to 51.7% in 2016. The multidrug resistance percentage for Pseudomonas aeruginosa was 26.9% and was relatively stable over time. The percentage of extended-spectrum β-lactamase (ESBL)-positive isolates among Escherichia coli and Klebsiella pneumoniae was 20.1% and 55.7%, respectively. Resistance to amikacin, meropenem and tigecycline was low among E. coli and K. pneumoniae and the ESBL-producing subset (≤5.9%). Among Staphylococcus aureus isolates, 36.7% were methicillin-resistant (MRSA); percentages varied year-on-year. No S. aureus isolates, including MRSA, were resistant to linezolid, vancomycin or tigecycline. Among Enterococcus faecium isolates, resistance was 22.6% to vancomycin and 2.3% to linezolid; no isolates were resistant to tigecycline.

CONCLUSION

This study shows low resistance to meropenem and tigecycline among Enterobacteriaceae isolates and continued activity of linezolid, vancomycin and tigecycline against Gram-positive organisms. However, antimicrobial resistance continues to be problematic in Eastern Europe and requires continued surveillance.