Assessment of two commercial susceptibility test methods for determination of daptomycin MICs.

Daptomycin is a lipopeptide antibiotic with activity against several important gram-positive bacterial pathogens, including drug-resistant staphylococci and enterococci. Because the mechanism of action of daptomycin is calcium-dependent depolarization of the cell membrane, susceptibility testing requires medium supplemented with a physiological level of calcium. This study assessed two Food and Drug Administration-cleared commercial test devices for determination of daptomycin MICs, Etest and JustOne.

Multilaboratory evaluation of disk diffusion antimicrobial susceptibility testing of Neisseria meningitidis isolates.

In 2005, the Clinical and Laboratory Standards Institute published MIC interpretive criteria for 13 antimicrobial agents used for either therapy or prophylaxis of Neisseria meningitidis infections. The MIC method includes the use of lysed horse blood-supplemented Mueller-Hinton broth with incubation in 5% CO2 for 20 to 24 h. Since some clinical laboratories might prefer the option of disk diffusion testing for infrequently encountered isolates a multicenter collaborative study was conducted to evaluate the reproducibility of a disk diffusion method for testing isolates of N.

Susceptibility of Neisseria meningitidis to 16 antimicrobial agents and characterization of resistance mechanisms affecting some agents.

Neisseria meningitidis represents a pathogen of great public health importance in both developed and developing countries. Resistance to some antimicrobial agents used either for therapy of invasive infections or for prophylaxis of case contacts has long been recognized, although specific guidelines for susceptibility testing have not been fully developed. We have examined the susceptibilities of a collection of 442 meningococcal clinical isolates from 15 countries to 16 antimicrobial agents.

Induction of telithromycin resistance by erythromycin in isolates of macrolide-resistant Staphylococcus spp.

Staphylococcal isolates were examined for possible macrolide-inducible resistance to telithromycin. All macrolide-resistant isolates demonstrated telithromycin D-shaped zones. This result did not discriminate between resistance due to an efflux mechanism (msrA) or a ribosomal target modification (ermA or ermC).

International clone of Neisseria meningitidis serogroup A with tetracycline resistance due to tet(B).

Thirteen Neisseria meningitidis clinical isolates from Africa, Asia, and the United States for which the tetracycline MICs were elevated (> or =8 microg/ml) were examined for 14 recognized resistance genes. Only the drug efflux mechanism encoded by tet(B) was detected. All isolates were in serogroup A, belonged to complex ST-5, and were closely related by pulsed-field gel electrophoresis analysis.

Activities of cethromycin and telithromycin against recent North American isolates of Streptococcus pneumoniae.

The in vitro activities of two investigational ketolides, cethromycin (formerly ABT-773) and telithromycin, were determined for a selected group of 312 Streptococcus pneumoniae isolates from a national surveillance program. The MIC of cethromycin at which 50% of the isolates were inhibited was 0.008 micro g/ml, and the MIC at which 90% of the isolates were inhibited was 0.

In vitro activity of daptomycin against vancomycin-resistant enterococci of various Van types and comparison of susceptibility testing methods.

The increasing prevalence of vancomycin-resistant enterococcal (VRE) infections and the limited number of antimicrobial agents for their treatment emphasize a need for new, more effective agents. In this study, the in vitro activity of daptomycin was determined against a collection of 156 VRE from seven different institutions. Van types were characterized by PCR, and pulsed-field gel electrophoresis was performed to exclude isolates with >85% relatedness by dendrogram.

Femoral anteversion in infants: a method using ultrasound.

Objective: To design a reproducible method to measure femoral anteversion in children under 1 year old.

Design And Patients: We conducted a prospective, observational study to determine intra- and inter-observer reproducibility of the sonographic measurement of femoral anteversion in infants. The method involves imaging of the proximal femur using a vertical transducer with the infant in the lateral position.

Comparative activities of the oxazolidinone AZD2563 and linezolid against selected recent North American isolates of Streptococcus pneumoniae.

The activity of AZD2563 against 250 highly resistant pneumococci and 267 drug-susceptible isolates was determined. The AZD2563 MICs for 50 and 90% of the strains tested were 1 and 2 micro g/ml and 0.5 and 1 micro g/ml, respectively, for the two isolate groups.