Real-time PCR for pharmacodynamic studies of Chlamydia trachomatis.

Pharmacodynamic knowledge about Chlamydia trachomatis exposed to antibiotics is hampered due to methodological limitations. We have developed a quantitative real-time PCR method (qRT-PCR) for determination of viable C. trachomatis.

Postantibiotic and sub-MIC effects of benzylpenicillin against Streptococcus pneumoniae with different susceptibilities for penicillin.

Background: The purpose of the study was to examine whether penicillin-susceptible and nonsusceptible strains of Streptococcus pneumoniae exhibited different pharmacodynamic responses to benzylpenicillin.

Methods: The postantibiotic effects (PAEs) and the postantibiotic sub-MIC effects (PA SMEs) were investigated by optical density against strains of S. pneumoniae with different susceptibilities to benzylpenicillin.

Bacteria with increased mutation frequency and antibiotic resistance are enriched in the commensal flora of patients with high antibiotic usage.

Background: We examined how prolonged antibiotic treatment affected the resistance and mutation frequency of human microflora isolated from intestine (Escherichia coli, enterococci spp.), pharynx (alpha-streptococci) and nostril (coagulase-negative staphylococci, CoNS).

Methods: Samples were collected from patients at the Center of Cystic Fibrosis (n=18) and the haematology ward (n=18) of the University Hospital, Uppsala, Sweden.

Fitness of antibiotic resistant Staphylococcus epidermidis assessed by competition on the skin of human volunteers.

Background: Antibiotic resistance typically confers a biological fitness cost on bacteria that can be manifested as a decreased growth rate in culture media and experimental animals. However, there are limited experimental data on the relative fitness of resistant and susceptible bacteria during growth in their natural environment.

Objective: We have developed a human competition model to investigate the relative fitness of antibiotic-resistant and -susceptible bacteria.

Suboptimal antibiotic dosage as a risk factor for selection of penicillin-resistant Streptococcus pneumoniae: in vitro kinetic model.

Optimizing pharmacokinetic/pharmacodynamic indices of antibiotics to obtain clinical and microbiological efficacy is essential, but dosing regimens must also be tailored to minimize the risk for emergence of resistance. The aim of the present study was to investigate whether certain concentrations of benzylpenicillin are critical for the selection of resistant subpopulations. A mixed culture of Streptococcus pneumoniae containing ca.

Pharmacodynamics of moxifloxacin against Streptococcus pyogenes in an in vitro kinetic model.

The aim of the present study was to investigate the pharmacodynamics of moxifloxacin against strains of Streptococcus pyogenes with different susceptibilities to erythromycin by using an in vitro kinetic model simulating human pharmacokinetics of moxifloxacin at oral doses of 400 and 200 mg, respectively. When the different strains of S. pyogenes were exposed to the higher dose, the number of bacteria was reduced below the detection limit after 12 h and no regrowth was noted during the following 12 h.