Acquired resistance to macrolides in Pseudomonas aeruginosa from cystic fibrosis patients.

Cystic fibrosis (CF) patients receive chronic treatment with macrolides for their antivirulence and anti-inflammatory properties. We, however, previously showed that Pseudomonas aeruginosa, considered as naturally resistant to macrolides, becomes susceptible when tested in a eukaryotic medium rather than a conventional broth.We therefore looked for specific macrolide resistance determinants in 333 CF isolates from four European CF centres in comparison with 48 isolates from patients suffering from hospital-acquired pneumonia (HAP).Minimum inhibitory concentrations (MICs) of macrolides and ketolides measured in eukaryotic medium (RPMI-1640) were higher towards CF than HAP isolates. Gene sequencing revealed mutations at three positions (2045, 2046 and 2598) in domain V of 23S rRNA of 43% of sequenced CF isolates, but none in HAP isolates. Enzymes degrading extracellular polymeric substances also reduced MICs, highlighting a role of the mucoid, biofilm-forming phenotype in resistance. An association between high MICs and chronic azithromycin administration was evidenced, which was statistically significant for patients infected by the Liverpool Epidemic Strain.Thus, ribosomal mutations are highly prevalent in CF isolates and may spread in epidemic clones, arguing for prudent use of oral macrolides in these patients. Measuring MICs in RPMI-1640 could be easily implemented in microbiology laboratories to phenotypically detect resistance.

Antimicrobial Susceptibility of Pseudomonas aeruginosa Isolated from Cystic Fibrosis Patients in Northern Europe.

Pseudomonas aeruginosa is a major cause of morbidity and mortality in cystic fibrosis patients. This study compared the antimicrobial susceptibilities of 153 P. aeruginosa isolates from the United Kingdom (UK) (n = 58), Belgium (n = 44), and Germany (n = 51) collected from 118 patients during routine visits over the period from 2006 to 2012. MICs were measured by broth microdilution. Genes encoding extended-spectrum ß-lactamases (ESBL), metallo-ß-lactamases, and carbapenemases were detected by PCR. Pulsed-field gel electrophoresis and multilocus sequence typing were performed on isolates resistant to ≥3 antibiotic classes among the penicillins/cephalosporins, carbapenems, fluoroquinolones, aminoglycosides, and polymyxins. Based on EUCAST/CLSI breakpoints, susceptibility rates were ≤30%/≤40% (penicillins, ceftazidime, amikacin, and ciprofloxacin), 44 to 48%/48 to 63% (carbapenems), 72%/72% (tobramycin), and 92%/78% (colistin) independent of patient age. Sixty percent of strains were multidrug resistant (MDR; European Centre for Disease Prevention and Control criteria). Genes encoding the most prevalent ESBL (BEL, PER, GES, VEB, CTX-M, TEM, SHV, and OXA), metallo-ß-lactamases (VIM, IMP, and NDM), or carbapenemases (OXA-48 and KPC) were not detected. The Liverpool epidemic strain (LES) was prevalent in UK isolates only (75% of MDR isolates). Four MDR sequence type 958 (ST958) isolates were found to be spread over the three countries. The other MDR clones were evidenced in ≤3 isolates and localized in a single country. A new sequence type (ST2254) was discovered in one MDR isolate in Germany. Clonal and nonclonal isolates with different susceptibility profiles were found in 20 patients. Thus, resistance and MDR are highly prevalent in routine isolates from 3 countries, with meropenem, tobramycin, and colistin remaining the most active drugs.

Intranasal formulation of erythropoietin (EPO) showed potent protective activity against amyloid toxicity in the Aß25₋35 non-transgenic mouse model of Alzheimer's disease.

Erythropoietin (EPO) promotes neurogenesis and neuroprotection. We here compared the protection induced by two EPO formulations in a rodent model of Alzheimer's disease (AD): rHu-EPO and a low sialic form, Neuro-EPO. We used the intracerebroventricular administration of aggregated Aß25₋35 peptide, a non-transgenic AD model. rHu-EPO was tested at 125-500 µg/kg intraperitoneally and Neuro-EPO at 62-250 µg/kg intranasally (IN). Behavioural procedures included spontaneous alternation, passive avoidance, water-maze and object recognition, to address spatial and non-spatial, short- and long-term memories. Biochemical markers of Aß25₋35 toxicity in the mouse hippocampus were examined and cell loss in the CA1 layer was determined. rHu-EPO and Neuro-EPO led to a significant prevention of Aß25₋35-induced learning deficits. Both EPO formulations prevented the induction of lipid peroxidation in the hippocampus, showing an antioxidant activity. rHu-EPO (250 µg/kg) or Neuro-EPO (125 µg/kg) prevented the Aß25₋35-induced increase in Bax level, TNFα and IL-1ß production and decrease in Akt activation. A significant prevention of the Aß25₋35-induced cell loss in CA1 was also observed. EPO is neuroprotective in the Aß25₋35 AD model, confirming its potential as an endogenous neuroprotection system that could be boosted for therapeutic efficacy. We here identified a new IN formulation of EPO showing high neuroprotective activity. Considering its efficacy, ease and safety, IN Neuro-EPO is a new promising therapeutic agent in AD.