Study links rates of intrinsically resistant bacteria with acquired resistance
An analysis of data from routine antibiotic susceptibility testing in 30 European countries shows a strong correlation between the rates of intrinsically antibiotic-resistant bacterial species and the rates of acquired resistance in gram-negative bacterial species, a team of European researchers reported today in Eurosurveillance.
Using data reported for 2016 to the European Antimicrobial Resistance Surveillance Network (EARS-Net), the researchers set out to compare the country-specific distribution of four gram-negative species (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter spp.) and the proportions of selected acquired resistance traits within these species. Data included isolates from blood and cerebrospinal fluid, both considered markers of bloodstream infections. The study was limited to only include antibiotics commonly used for first-line treatment of bacteremia caused by gram-negative species and routinely included in susceptibility testing.
The country-specific species distribution varied considerably. While E coli accounted for 31.9% (Greece) to 81% (Iceland) of all reported isolates, the two most common intrinsically resistant species, P aeruginosa and Acinetobacter spp., combined accounted for 5.5% (Norway) to 39.2% (Greece) of all isolates. Similarly, large national differences were noted for the percentages of acquired non-susceptibility to third-generation cephalosporins, carbapenems, and fluoroquinolones.
The analysis found a strong positive rank correlation between the country-specific percentages of P aeruginosa and Acinetobacter spp. combined and the percentages of non-susceptibility to the above antibiotics in all four species, with Spearman's rank correlation co-efficient (a measurement of the strength and direction of association between two variables) being greater than 0.75 for 10 of the 11 pairs of variables tested.
"In short, the higher the proportion of the two most intrinsically resistant species P aeruginosa and Acinetobacter spp., the higher the percentages of acquired non-susceptibility in E coli, K pneumoniae, P aeruginosa, and Acinetobacter spp., a point that directly indicates the burden of intrinsic resistance," the authors of the study write.
The authors suggest the differences are probably related to national differences in antibiotic consumption and infection prevention and control routines.
Aug 15 Eurosurveill study
Analysis points to gaps in the antibiotics pipeline
A new analysis of the small-molecule antibiotics pipeline highlights some of the key gaps in antibiotic development.
The analysis from the Pew Charitable Trusts, published yesterday in Nature Reviews Drug Discovery, found that of the 67 antibiotic candidates that have been in some stage of clinical development since 2014, only 10 have been approved by the US Food and Drug Administration, while 17 have been either suspended or discontinued and an additional 10 candidates have stalled. Only two of the 10 approved drugs are novel treatments, and none target the type of multidrug-resistant gram-negative organisms that the World Health Organization has identified as high-priority pathogens.
Of the 67 antibiotic candidates analyzed, 41 target gram-positive pathogens, which are typically less challenging to treat than gram-negatives.
"A continued area of unmet need is new treatments for bacterial infections caused by multidrug- or extensively drug-resistant gram-negative pathogens," the authors write.
The authors conclude that while there are several promising initiatives focused on boosting research and discovery efforts, innovative economic models are needed to ensure the availability of new antibiotics.
Aug 14 Nat Rev Drug Discov article