Multicenter Evaluation of the Simplexa VZV Direct Assay for Detection of Varicella-Zoster Virus in Cerebrospinal Fluid and Lesion-Swab Specimens.

Varicella-zoster virus (VZV) is the etiologic agent of varicella (chickenpox) and herpes zoster (shingles) infections commonly involving skin, mucous membranes, and less frequently the central nervous system. Traditional methods for the laboratory diagnosis of these infections are time-consuming, labor-intensive, and often insensitive. As such, these tests are being replaced by more sensitive and rapid molecular methods. This study evaluated the performance of two different molecular assays, the Simplexa VZV Direct and Simplexa VZV Swab Direct, to detect VZV DNA in cerebrospinal fluid (CSF) and lesion-swab specimens, respectively. The Simplexa VZV Direct and Simplexa VZV Swab Direct assays were compared against individual composite reference methods that varied depending on the sample cohort examined. A total of 883 CSF and 452 cutaneous and mucocutaneous prospective, retrospective, and contrived specimens were evaluated in this multicenter study. The results of this study showed that the Simplexa assays demonstrated near perfect agreement (k = 0.98) compared to the composite reference methods for the detection of VZV in CSF and lesion swab specimens. A further comparison between the standard of care molecular assays employed at the site of specimen collection and the Simplexa assays demonstrated excellent agreement (k = 1.0). The Simplexa assays offer rapid and reliable alternatives for the detection of VZV in certain clinical specimens without the need for nucleic acid extraction.

Comparison of the minimum inhibitory, mutant prevention and minimum bactericidal concentrations of ciprofloxacin, levofloxacin and garenoxacin against enteric Gram-negative urinary tract infection pathogens.

Acute, uncomplicated urinary tract infections (UTIs) are among the most commonly encountered bacterial infections and management has been made more complicated in the last decade due to the trend toward increasing antimicrobial resistance to ampicillin and trimethoprim/sulfamethoxazole (TMP/SMX). Fluoroquinolones are suggested as alternative antimicrobials for the treatment of UTIs in communities for which TMP/SMX resistance is > or = 10%. The mutant-prevention concentration (MPC) is a novel susceptibility parameter designed to minimize the selection of first-step resistant mutants present in large, > or = 10(10) CFU/mL, heterogeneous bacterial populations and is a distinct measurement from minimum inhibitory concentration testing. We measured MPC results for 80 enteric Gram-negative and 20 Pseudomonas aeruginosa urinary isolates against ciprofloxacin, levofloxacin and garenoxacin. Ciprofloxacin, levofloxacin and garenoxacin MPC results for Escherichia coli, Citrobacter freundii, Enterobacter cloacae, Klebsiella pneumoniae and P. aeruginosa respectively were 0.5, 1, 1, 1 and 4 mg/L; 1, 2, 4, 2 and 16 mg/L; 1, 8, >8, 4 and > or = 32 mg/L. By comparison, minimum inhibitory concentration (MIC)90 results for the Enterobacteriaceae organisms ranged from < or = 0.06-4 mg/L for the three drugs and 1-4 mg/L against P. aeruginosa. Similarly, MBC90 results ranged from < or = 0.06-4 mg/L and 2-8 mg/L respectively. For ciprofloxacin against E. coli, E. cloacae and K. pneumoniae and for levofloxacin against E. coli, C. freundii and K. pneumoniae, MPC results were below susceptible breakpoints and within clinically achievable and sustainable drug concentrations for >24 hours of the dosing interval against. For garenoxacin, urine drug concentrations are expected to be in excess of MPC results for the entire length of the dosing interval for E. coli. Application of MPCs to fluoroquinolones and management of UTIs represents a situation where high levels of in vitro activity, based on low MICs, is reflected in correspondingly low MPC values for most of the organisms tested. Incorporation of MPC strategies into current fluoroquinolone dosing in UTI represents a realistic approach for preventing the further selection of resistant organisms associated with UTIs.

Moxifloxacin: a review of the microbiological, pharmacological, clinical and safety features.

Antimicrobial agents are used to treat patients with infectious diseases. Initial antimicrobial compounds originated from natural sources and were generally deemed to be narrow in spectrum. Today, we are in the era of designer drugs that have been specifically developed with current issues in infectious diseases in mind. For example, some new compounds require once daily dosing, have minimal side effects, are active against resistant pathogens and, for some, have a lower propensity for selecting for antimicrobial resistance during patient therapy.