Le FORUM, Vol. 39 No. 3

https://digitalcommons.library.umaine.edu/francoamericain_forum/1046/thumbnail.jp

Revue d'histoire du Bas-Saint-Laurent, vol. 12 (3-4)

Mot de l'éditeur -- Au micro de CJBR -- La grande histoire de CJBR -- Jules-A. Brillant et le poste CJBR -- Avec CJBR, un bon en avant pour le Bas St-Laurent -- CJBR, l'école -- L'annonceur: un éducateur populaire -- Sandy Burgess : le journaliste que j'ai connu -- "Ce pays qui est le mien" -- Un demi-siècle d'information: que de nouvelles! -- Journaliste de père en fils à CJBR -- Le théâtre à CJBR -- 50 ans de musique à CJBR, le château fort de la mélodie française -- Poésie, théâtre, jazz et originalité avec Michel Garneau -- Les "Chroniques du dimanche", l'âge d'or de la critique culturelle à CJBR -- "Si CJBR m'était conté..." -- L'évolution technologique, un élément-clef de l'histoire des 50 ans de radiodiffusion -- La publicité à CJBR, quarante ans de croissance -- Des pionnières à CJBR -- 1958-1972, des années enrichissantes -- De Trois-Pistoles à Rimouski -- Le sport et son enracinement dans le milieu régional -- "Debout c'est l'heure", c'est Jean Brisson qui sonne le réveil -- "Par une belle journée de tempête" -- Et on repart vers la centain

Le Forum, Vol. 42 No. 1

https://digitalcommons.library.umaine.edu/francoamericain_forum/1094/thumbnail.jp

Studies on the mechanisms of resistance to fluoroquinolone antimicrobial agents in pseudomonas aeruginosa

Bibliography: p. 230-254

<i>Staphylococcus aureus</i> Small-Colony Variants from Airways of Adult Cystic Fibrosis Patients as Precursors of Adaptive Antibiotic-Resistant Mutations

Prototypic Staphylococcus aureus and their small-colony variants (SCVs) are predominant in cystic fibrosis (CF), but the interdependence of these phenotypes is poorly understood. We characterized S. aureus isolates from adult CF patients over several years. Of 18 S. aureus-positive patients (58%), 13 (72%) were positive for SCVs. Characterization included genotyping, SCCmec types, auxotrophy, biofilm production, antibiotic susceptibilities and tolerance, and resistance acquisition rates. Whole-genome sequencing revealed that several patients were colonized with prototypical and SCV-related clones. Some clonal pairs showed acquisition of aminoglycoside resistance that was not explained by aminoglycoside-modifying enzymes, suggesting a mutation-based process. The characteristics of SCVs that could play a role in resistance acquisition were thus investigated further. For instance, SCV isolates produced more biofilm (p hemB) acquired resistance to ciprofloxacin and gentamicin faster than its parent counterpart after serial passages in the presence of sub-inhibitory concentrations of antibiotics. These results suggest a role for SCVs in the establishment of persistent antibiotic-resistant clones in adult CF patients

RWJ-54428 (MC-02,479), a New Cephalosporin with High Affinity for Penicillin-Binding Proteins, Including PBP 2a, and Stability to Staphylococcal Beta-Lactamases

RWJ-54428 (MC-02,479) is a new cephalosporin active against gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA). The potency of this new cephalosporin against MRSA is related to a high affinity for penicillin-binding protein 2a (PBP 2a), as assessed in a competition assay using biotinylated ampicillin as the reporter molecule. RWJ-54428 had high activity against MRSA strains COL and 67-0 (MIC of 1 μg/ml) and also showed affinity for PBP 2a, with a 50% inhibitory concentration (IC(50)) of 0.7 μg/ml. RWJ-54428 also displayed excellent affinity for PBP 5 from Enterococcus hirae R40, with an IC(50) of 0.8 μg/ml and a MIC of 0.5 μg/ml. The affinity of RWJ-54428 for PBPs of β-lactam-susceptible S. aureus (MSSA), enterococci (E. hirae), and Streptococcus pneumoniae showed that the good affinity of RWJ-54428 for MRSA PBP 2a and E. hirae PBP 5 does not compromise its binding to susceptible PBPs. RWJ-54428 showed stability to hydrolysis by purified type A β-lactamase isolated from S. aureus PC1. In addition, RWJ-54428 displayed low MICs against strains of S. aureus bearing the four classes of staphylococcal β-lactamases, including β-lactamase hyperproducers. The frequency of isolation of resistant mutants to RWJ-54428 from MRSA strains was very low. In summary, RWJ-54428 has high affinity to multiple PBPs and is stable to β-lactamase, properties that may explain our inability to find resistance by standard methods. These data are consistent with its excellent activity against β-lactam-resistant gram-positive bacteria