Dalfopristin

About: Dalfopristin is a research topic. Over the lifetime, 696 publications have been published within this topic receiving 26621 citations. The topic is also known as: RP-54476 & Dalfopristina.

Activity of ceftobiprole compared with those of other agents against Staphylococcus aureus strains with different resistotypes by time-kill analysis

Abstract: Using a biofilm model, infections by Staphylococcus aureus, coagulase-negative staphylococci and enterococci were studied. The biofilms were exposed to quinupristin/dalfopristin and five comparator antibiotics: ciprofloxacin, vancomycin, teicoplanin, flucloxacillin and erythromycin. Two methods of exposure to the drugs were used: constant for 1 h, and exponentially decreasing, with the rate of dilution being matched to the half-lives of the antibiotics. The effects of antibiotic exposure were monitored by performing viable counts on the cells eluted from the biofilms. The results are presented as the inhibitory or bactericidal effect (the reduction in numbers of bacteria eluted from the biofilms) and recovery times (the time taken for the number of cells eluted from the biofilms to return to the number eluted before the drug exposure). Quinupristin/dalfopristin was the most effective of the six antibiotics studied, especially against enterococci. However, there were no significant differences in the effects, inhibitory/ bactericidal or recovery times, produced by the two methods of exposure. The two glyco-peptides showed a surprising lack of activity.

The effects of exposure at constant (1 h) or exponentially decreasing concentrations of quinupristin/dalfopristin on biofilms of Gram-positive bacteria

Abstract: Using a biofilm model, infections by Staphylococcus aureus, coagulase-negative staphylococci and enterococci were studied. The biofilms were exposed to quinupristin/dalfopristin and five comparator antibiotics: ciprofloxacin, vancomycin, teicoplanin, flucloxacillin and erythromycin. Two methods of exposure to the drugs were used: constant for 1 h, and exponentially decreasing, with the rate of dilution being matched to the half-lives of the antibiotics. The effects of antibiotic exposure were monitored by performing viable counts on the cells eluted from the biofilms. The results are presented as the inhibitory or bactericidal effect (the reduction in numbers of bacteria eluted from the biofilms) and recovery times (the time taken for the number of cells eluted from the biofilms to return to the number eluted before the drug exposure). Quinupristin/dalfopristin was the most effective of the six antibiotics studied, especially against enterococci. However, there were no significant differences in the effects, inhibitory/ bactericidal or recovery times, produced by the two methods of exposure. The two glyco-peptides showed a surprising lack of activity.

Technological characterisation, antibiotic susceptibility and antimicrobial activity of wild-type Leuconostoc strains isolated from North Italian traditional cheeses.

Abstract: Genotypic and technological properties, antibiotic susceptibility and antimicrobial activity of 35 Leuconostoc strains, isolated from different Italian raw milk cheeses, were investigated. RAPD-PCR was used to study genetic variability and to distinguish closely related strains. The results showed a high degree of heterogeneity among isolates. All the strains had weak acidifying activity and showed low proteolytic and lipolytic activities. Reduction activity, was generally low. All the Leuconostoc were susceptible to ampicillin, mupirocin, erythromycin, quinupristin/dalfopristin and tetracycline. Many strains were classified as resistant to oxacillin, ciprofloxacin and nitrofurantonin, while all isolates were found resistant to vancomycin. PCR-based detection did not identify any of the common genetic determinants for vancomycin (vanA, vanB, vanC1, vanC2, vanC3, vanD, vanE, vanG) or erythromycin (ermB and ermC). Tetracycline resistance genes were detected in 25 tetracycline susceptible strains, the most frequent one being tetM. One strain, belonging to Ln. pseudomesenteroides species, was positive for the presence of the int gene of the Tn916/Tn1545 trasposon family. This is the first time the conjugative transposon Tn916 has been detected inside the Leuconostoc species. All strains showed antimicrobial activity against Enterococcus faecalis and Ent. faecium. The presence of genes encoding amino-acid decarboxylases (hdc and tdc) was not detected. Some strains are interesting in view of their use in cheese production as starter and non starter cultures.

Staphylococcus aureus and antibiotic resistance

Abstract: After the report of first case of methicillin-resistant Staphylococcus aureus (MRSA) in 1961, MRSA become a major problem worldwide. Over the last decade MRSA strains have emerged as serious pathogens in nosocomial and community settings. Glycopeptides (vancomycin and teicoplanin) are still the current mainstay of therapy for infections caused by MRSA. In the last decade dramatic changes have occurred in the epidemiology of MRSA infections. The isolates with reduced susceptibility and in vitro resistance to vancomycin have emerged. Recently, therapeutic alternatives such as quinupristin/dalfopristin, linezolid, tigecycline and daptomycin have been introduced into clinical practice for treating MRSA infections. Nevertheless, these drugs are only approved for certain indication and resistance has already been reported. In this review, the new information on novel drugs for treating MRSA infections and the resistance mechanisms of these drugs were discussed.