A real-time PCR for the detection and characterisation of Aspergillus species.

An early diagnosis of an invasive fungal infection is essential for the initiation of a specific antifungal therapy and to avoid unnecessary discontinuation of a baseline therapy for haematological or oncological diseases. A real-time PCR assay for the detection and strain identification of Aspergillus species from culture strains was evaluated. DNA preparation was evaluated in contaminated culture media, urine and serum. A LightCycler PCR to differentiate various Aspergillus species was established. A real-time PCR assay for the detection of Aspergillus species was improved and was able to detect and differentiate medically important Aspergillus spp. The sensitivity of the test was <10 plasmid equivalents/assay. The real-time PCR assay is a useful tool for the rapid identification of Aspergillus species and might be useful as an early diagnostic tool to detect an invasive fungal infection. A real-time PCR protocol was improved by generating plasmid standards, additional generation of melting curves for species identification and the correlation between the melting temperature and the nucleotide exchanges within the used 18S rRNA gene region.

Effect of moxifloxacin versus imipenem/cilastatin treatment on the mortality of mice infected intravenously with different strains of Bacteroides fragilis and Escherichia coli.

OBJECTIVES: To study the effect of moxifloxacin versus imipenem/cilastatin (hereafter referred to as imipenem) treatment on the mortality of mice infected intravenously with different strains of Bacteroides fragilis and Escherichia coli. METHODS: Groups of 20 mice each were infected intravenously with different strains of B. fragilis [moxifloxacin and imipenem susceptible or resistant, and enterotoxin (ET) positive or negative] and E. coli (moxifloxacin and imipenem susceptible). Twenty-four hours post-infection, intravenous therapy with either moxifloxacin (2.0 mg twice a day) or imipenem (2.4 mg three times a day) was started and continued for 3 days. Control groups were left untreated. Survival rates were recorded at day 7 post-infection. At that time, surviving mice were killed and numbers of bacteria in the liver and kidneys were determined. RESULTS: If compared with untreated animals, mice treated with either moxifloxacin or imipenem showed significantly improved survival (P < 0.001). There was no significant difference (P = 0.97) in the survival rates comparing the two treatment regimens irrespective of the ET positivity or the susceptibility to moxifloxacin or imipenem of the infective B. fragilis strain. However, there was a tendency that B. fragilis was recovered more often from the liver and kidneys of mice infected with ET positive strains. CONCLUSIONS: The data show that moxifloxacin was as efficacious as imipenem in reducing the mortality rate of mice suffering from a severe systemic aerobic/anaerobic infection.

Comparison of real-time PCR detection methods for B1 and P30 genes of Toxoplasma gondii.

Real-time PCR assays were established with the Toxoplasma gondii P30 and the 35-copy B1 gene as target genes. Both PCR methods detected Toxoplasma DNA from 10 to 100000 genome equivalents per assay and had comparable intra-assay deviations suggesting that detecting a single copy locus is suitable for clinical diagnostic.