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.

[Gram-positive bacterial infections resistant to antibiotic treatment].

Abstract: Antibiotic resistance has become a major problem in the treatment of gram-positive bacterial infections. These organisms are able to escape antibiotic activity through several mechanisms including beta-lactamase production, altered penicillin-binding proteins, aminoglycoside-modifying enzymes, modification of the target site of the antibiotic, and active efflux. Resistant determinants may be carried on the chromosome, and are transmitted vertically by clonal dissemination, or on mobile elements such as plasmids, transposons or integrons capable of horizontal transfer both within and between species. Several resistant genes can be inserted in a given integron, resulting in multi-drug resistance. Antimicrobial resistance mechanisms can be caused or induced following the widespread use of antibiotics. The most important gram-positive resistant organisms include penicillin-resistant Streptococcus pneumoniae, methicillin-resistant Staphylococcus aureus and coagulase-negative staphylococci, methicillin-resistant Staphylococcus aureus with intermediate resistance to vancomycin, and enterococcal strains that express high-level resistance to aminoglycosides and/or resistance to vancomycin. In several instances, these strains show multi-drug resistance and cannot be treated with currently available agents. Therapeutic strategies include the use of a higher antibiotic dosage, the use of alternative, non-conventional drugs, alone or in combination, after demonstration of their efficacy in vitro and in experimental animal models, and the development of new drugs. New agents available include quinupristin/dalfopristin and line-zolid with activity against most resistant gram-positive bacteria. Promising new drugs that may reach the market in the near future include daptomycin and oritavancin. Careful use of antibiotics and adherence to infection control standards are crucial in preventing the development and the spread of resistant organisms.

Development of provisional disc diffusion breakpoints for testing quinupristin/dalfopristin.

Abstract: Quinupristin/dalfopristin is an injectable streptogramin with broad activity against many Gram-positive bacteria, including Streptococcus pneumoniae, Staphylococcus aureus and Enterococcus faecium. Although a number of studies have reported the MICs of this compound against a variety of bacteria, there are no published reports of disc diffusion testing. We tested total disc masses of 7.5 and 15 μg with varying ratios of the component compounds, quinupristin and dalfopristin, combined in the following quinupristin: dalfopristin ratios (in μg): 7.5:0, 0:7.5, 10:5, 5:10, 5:2.5 and 2.5:5. Zone diameters and MICs were determined in parallel for 44 isolates of staphylococci, 47 isolates pneumococci and 64 isolates of enterococci. Control strains were included for each species tested, including a strain of Enterococcus faecalis with known resistance to quinupristin/dalfopristin. Using tentative definitions for quinupristin/dalfopristin of ≤2 mg/L as susceptible and ≥4 mg/L as resistant, each of the four discs containing ratios of both component compounds separated presumptive susceptible organisms from resistant ones better than either quinupristin or dalfopristin alone. The best correlation of zone sizes and MICs for predicting susceptibility to quinupristin/dalfopristin at an MIC of ≤2 mg/L was achieved with the 5 μg:10 μg disc and a zone diameter of ≥18 mm. These criteria may be useful for identifying organisms that are presumptively susceptible to quinupristin/dalfopristin.

Analysis of distribution characteristics and drug resistance of 2748 strains of pathogens isolated from burn patients

Abstract: Objective To provide epidemiological data of the distribution characteristics and drug resistance of the pathogens isolated from burn patients in recent years for guiding rational use of antibiotics in clinic. Methods Totally 2748 strains of pathogens were isolated from 1977 specimens (blood, catheter, wound excretion, etc.) collected from 478 patients hospitalized in Institute of Burn Research of Southwest Hospital from March 2003 to June 2011. After being identified by API strips, drug resistance of the 2748 isolated pathogens to 55 commonly-used antibiotics including gentamicin, tobramycin, piperacillin, amikacin, etc. was tested by K-B paper disk diffusion method. The WHONET 5.3 software was used to analyze the following subjects: the distribution of the pathogens with different types and different sources each year, the changes in drug-resistant rates of Gram negative bacilli, Gram positive cocci, and fungi to several antibiotics, and the changes in sensitive rates of Pseudomonas aeruginosa (PA), Staphylococcus aureus (SA), Acinetobacter baumannii (AB), Candida albicans (CA) to several antibiotics. Results Among 2748 strains of pathogens, 1879 strains of Gram negative bacilli accounted for 68.38%, 628 strains of Gram positive cocci accounted for 22.85%, and 241 strains of fungi accounted for 8.77%. The isolation rate of strains from wound excretion ranked the first (1022 strains accounted for 37.19%), followed by those from respiratory tract (995 strains accounted for 36.21%) and blood (421 strains accounted for 15.32%). Strains isolated from other types of specimens were rare. Isolation rate of PA ranked the first (996 strains accounted for 36.24%), followed by SA (495 strains accounted for 18.01%) and AB (395 strains accounted for 14.37%). Isolation rate of AB showed a trend of increase year by year, but that of SA presented the opposite trend. Isolation rate of PA was quite stable. There were 484 strains of methicillin resistant SA among Staphylococci, accounting for 17.61%. Resistant rates of PA and AB to polymyxin B and polymyxin E were below 30.00%, and those of PA and AB to other antibiotics, such as the third generation cephalosporins, β-lactams, aminoglycosides, and quinolones, were from 57.91% to 100.00%. Resistant rate of AB to minocycline was 39.68%. From 2004 to 2011, sensitive rate of PA to quinolone antibiotics showed an increasing trend year by year, but that of AB to minocycline, netilmicin, imipenem, meropenem, tobramycin, and cefoperazone/sulbactam presented the opposite trend. Resistant rates of Enterococcus faecalis, Enterococcus faecium, and SA to teicoplanin and linezolid were less than 10.00%. Resistant rate of SA, Staphylococcus epidermidis and Enterococcus faecium to vancomycin was 0. Resistant rates of SA to quinupristin/dalfopristin, minocycline, fusidic acid, and compound sulfamethoxazole were low, respectively 0.82%, 9.35%, 2.21%, and 31.85%. Sensitive rates of SA to erythromycin, clindamycin, compound sulfamethoxazole, tetracycline, and minocycline showed an increasing trend year by year. Both infection rate and resistant rate of fungi were low. The resistant rates of CA to 5 kinds of antibiotics were less than 15.00%. The sensitive rate of CA to 5-flucytosine declined slightly, and those of CA to the other 4 antibiotics showed an increasing trend year by year. Conclusions The three dominant pathogens that cause infection in burn patients hospitalized in Institute of Burn Research of Southwest Hospital in recent years are PA, SA, and AB in order. PA and AB are outstandingly multidrug-resistant among the isolated strains. AB might replace PA as the main pathogenic bacterium that cause the death of burn patients with infection.