Assessment of the Activity of Tigecycline against Gram-Positive and Gram-Negative Organisms Collected from Italy between 2012 and 2014, as Part of the Tigecycline Evaluation and Surveillance Trial (T.E.S.T.).

Stefania Stefani,Michael Dowzicky

doi:10.3390/ph9040074

Abstract

As part of the Tigecycline Evaluation and Surveillance Trial (T.E.S.T) we report the in vitro activity of tigecycline and its comparators against Gram-negative and Gram-positive organisms collected from Italian centers between 2012 and 2014. Minimum inhibitory concentrations were determined according to the broth microdilution methodology of the Clinical and Laboratory Standards Institute, and antimicrobial resistance was determined using the European Committee on Antimicrobial Susceptibility Testing interpretive criteria. Among the Enterobacteriaceae, 31% of Escherichia coli isolates, 22% of Klebsiella pneumoniae, and 1% of Klebsiella oxytoca were extended-spectrum β-lactamase producers (ESBLs). Resistance rates among ESBL-K. pneumoniae and ESBL-E. coli to meropenem were 24% and <1%, respectively. Thirty-seven percent of K. pneumoniae were multidrug resistant (MDR) strains. Resistance rates among isolates of Acinetobacter baumannii to amikacin, levofloxacin and meropenem were between 84% and 94%. Eighty percent of A. baumannii isolates were MDR strains. Methicillin-resistant Staphylococcus aureus (MRSA) accounted for 38% of S. aureus isolates. No isolates of MRSA were resistant to linezolid, tigecycline or vancomycin. Antimicrobial resistance remains a problem in Italy with increasing numbers of MDR organisms. Despite high levels, MRSA rates appear to be stabilising. Tigecycline retains its in vitro activity against the majority of organisms, including those with multidrug resistance.

Highlights

Across Europe the overuse and misuse of antibiotics has led to increasing rates of antimicrobial resistance, in the southern and eastern areas [1]
Has relatively high rates of antimicrobial resistance compared to other parts of Europe [1]
Comparisons between the two studies are limited because the current report uses the European Committee on Antimicrobial Susceptibility Testing (EUCAST) criteria for determining susceptibility and resistance and the previous publication used the Clinical and Laboratory Standards Institute (CLSI) interpretive criteria [8,11]

Summary

Introduction

Across Europe the overuse and misuse of antibiotics has led to increasing rates of antimicrobial resistance, in the southern and eastern areas [1]. A recent report by the European Antimicrobial Resistance Surveillance Network (EARS-Net) showed that in Italy there were increasing rates of resistance among isolates of Klebsiella pneumoniae, Escherichia coli and Acinetobacter spp. to a range of antimicrobial agents, including fluoroquinolones, third-generation cephalosporins, aminoglycosides and carbapenems, alone, or in combination [1]. This rise in multidrug resistance has increased the use of carbapenems resulting in escalating numbers of carbapenem-resistant bacteria [5]. Rates of penicillin- and macrolide-non-susceptibility among Streptococcus pneumoniae remain high in Italy [1]

Methods

Results

Conclusion