Antimicrobial agents and chemotherapy
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Antimicrob. Agents Chemother. · Sep 2009
Candida albicans and Staphylococcus aureus form polymicrobial biofilms: effects on antimicrobial resistance.
Candida albicans readily forms biofilms on the surface on indwelling medical devices, and these biofilms serve as a source of local and systemic infections. It is estimated that 27% of nosocomial C. albicans bloodstream infections are polymicrobial, with Staphylococcus aureus as the third most common organism isolated in conjunction with C. albicans. We tested whether S. aureus and C. albicans are able to form a polymicrobial biofilm. ⋯ In addition, S. aureus matrix staining revealed a different phenotype in polymicrobial versus monomicrobial biofilms, suggesting that S. aureus may become coated in the matrix secreted by C. albicans. S. aureus resistance to vancomycin was enhanced within the polymicrobial biofilm, required viable C. albicans, and was in part mediated by C. albicans matrix. However, the growth or sensitivity to amphotericin B of C. albicans is not altered in the polymicrobial biofilm.
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Antimicrob. Agents Chemother. · Sep 2009
Prevalence and characterization of heterogeneous vancomycin-intermediate Staphylococcus aureus isolates from 14 cities in China.
The prevalence of heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) among 1,012 vancomycin-susceptible methicillin (meticillin)-resistant S. aureus isolates collected from 14 cities in China from 2005 to 2007 was 13 to 16%, as determined by a combination of (i) measurement by the modified population analysis profile-area under the curve method (PAP-AUC) and (ii) estimation from the measured sensitivity and specificity of a screening method. Two hundred isolates from blood were chosen as a subset for measurement of the sensitivities and the specificities of several previously described screening methods by using the results of PAP-AUC as the reference. During this testing, one isolate was found to be a vancomycin-intermediate S. aureus (VISA) strain so was not used in the evaluation of the screening tests. ⋯ The precision of that estimate was assessed by reapplying the screening cascade to 120 randomly selected isolates from the 812 non-blood isolates and simultaneously determining their heterogeneous vancomycin-intermediate susceptibility status by PAP-AUC. Because PAP-AUC is impractical for use with large numbers of isolates, the screening-based estimation method is useful as a first approximation of the prevalence of hVISA. Of the 27 VISA or hVISA isolates from blood, 22.2% and 74.1% were staphylococcal chromosome cassette mec types II and III, respectively, while 77.8% and 22.2% were agr type 1 and agr type 2, respectively; the MIC ranges were 0.5 to 4 mg/liter for vancomycin and 0.25 to 1 mg/liter for daptomycin.
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Antimicrob. Agents Chemother. · Sep 2009
Randomized Controlled TrialIntravenous doripenem at 500 milligrams versus levofloxacin at 250 milligrams, with an option to switch to oral therapy, for treatment of complicated lower urinary tract infection and pyelonephritis.
The prospective, multicenter, double-blind study presented in this report evaluated whether or not intravenous (IV) administration of doripenem, a carbapenem with bactericidal activity against gram-negative and gram-positive uropathogens, is inferior to IV administration of levofloxacin in the treatment of complicated urinary tract infection (cUTI). Patients (n = 753) with complicated lower UTI or pyelonephritis were randomly assigned to receive IV doripenem at 500 mg every 8 h (q8h) or IV levofloxacin at 250 mg q24h. Patients in both treatment arms were eligible to switch to oral levofloxacin after 3 days of IV therapy to complete a 10-day treatment course if they demonstrated significant clinical and microbiological improvements. ⋯ Both treatment regimens were generally well tolerated. Doripenem was found not to be inferior to levofloxacin in terms of therapeutics and is now approved for use in the United States and Europe for the treatment of adults with cUTI, including pyelonephritis. As fluoroquinolone resistance increases, doripenem may become a more important option for successful treatment of cUTIs, including treatment of pyelonephritis.