Detection of pathogenic fungi in human blood by the polymerase chain reaction

The ability of the polymerase chain reaction (PCR) to detect pathogenic fungi in human blood was investigated. A DNA fragment of about 300 bp from the 18S rDNA, highly conserved in all fungi, was amplified with target DNA from 18 different species of fungi commonly isolated from clinical samples. The presence of PCR products was confirmed by hybridization with a fluorescein-labelled internal probe (21-mer). The PCR assay described is sensitive enough to detect 125 fg of purified Candida albicans DNA and 10 to 100 yeast cells per millilitre of blood.

Correlation of in-vitro susceptibility test results with clinical response: a study of azole therapy in AIDS patients

The in-vitro susceptibilities of 40 clinical isolates of Candida albicans to ketoconazole and fluconazole were determined and an attempt was made to correlate these data with the clinical responses of the patients from whom the strains were originally isolated to treatment with these agents. Of 40 patients with the acquired immunodeficiency syndrome (AIDS) with oropharyngeal and/or oesophageal candidosis, 21 received ketoconazole and 19 fluconazole. Susceptibility testing was performed by a microbroth dilution method with RPMI-2% glucose medium according to the recommendations of the National Committee for Clinical Laboratory Standards; growth inhibition was estimated spectrophotometrically and the MIC endpoint was defined in terms of the IC1/2. The MICs of 236 additional strains of C. albicans, which were also isolated from AIDS patients, were used to establish a susceptibility profile for this species. On the basis of the susceptibility test results and the clinical responses of the 40 patients, the following tentative breakpoints for ketoconazole and fluconazole are proposed: patients with infections caused by C. albicans strains with MICs of ketoconazole and fluconazole or < or = 0.001 and < or = 0.25 mg/L respectively would be expected to respond to treatment with these agents and isolates with MICs which meet these criteria are therefore classified as susceptible; patients with infections caused by strains with MICs of ketoconazole and fluconazole of > or = 0.06 and > or = 16.0 mg/L respectively would not be expected to respond to treatment with these agents and isolates with MICs which meet these criteria are therefore classified as resistant; the response of patients with infections caused by strains with MICs of ketoconazole and fluconazole of 0.003-0.03 and 0.5-8.0 mg/L respectively cannot be reliably predicted and isolates with MICs which fall within these ranges are therefore classified as being of indeterminate susceptibility. The present study demonstrates that the results of in-vitro susceptibility testing with RPMI-2% glucose broth correlate with the clinical response to therapy and can be used to facilitate optimal treatment in AIDS patients with oropharyngeal and/or oesophageal candidosis.

Comparative in-vitro activity of four peptide antibiotics against penicillin-resistant Streptococcus pneumoniae isolated from cerebrospinal fluid (CSF)

The in-vitro activity of four peptide antibiotics against 43 penicillin-resistant Streptococcus pneumoniae isolated from cerebrospinal fluid (CSF) was evaluated. The activity of SKF104662 was slightly greater to that of vancomycin, teicoplanin and daptomycin (MICs for 90% of the isolates tested 0.06, 0.25, 0.12 and 0.25 mg/L, respectively) and superior to the other 15 drugs tested. The serotype of these penicillin-resistant strains was also determined. The strains that belonged to the predominant serotype 9 were resistant only to penicillin. All six erythromycin- and clindamycin-resistant strains belonged to serotype 6 and three of them were also resistant to chloramphenicol and tetracycline (plus penicillin).

Urinary tract infection caused by Corynebacterium group D2: report of 82 cases and review

Corynebacterium group D2 (CGD2) is a slow-growing, urea-splitting, multiantibiotic-resistant microorganism that is frequently isolated from urine samples and that, in certain circumstances, produces infection of the lower urinary tract (acute and chronic cystitis) and the upper urinary tract (pyelonephritis). This paper analyzes (by means of a retrospective and partially prospective clinical protocol) our experience with 82 patients with CGD2 bacteriuria. The infection was symptomatic in 62% of cases, and the clinical diagnoses included acute and chronic cystitis and pyelonephritis with or without bacteremia. Because CGD2 infection of the urinary tract may require specific antimicrobial treatment and because CGD2 is a fastidious microorganism, we recommend prolonged incubation of urine cultures (up to 48-72 hours), especially if the routine culture is negative, when patients are symptomatic, have alkaline urine, or have struvite crystals in the urine sediment.