Screening of presumptive urinary tract infections by the automated urine sediment analyser sediMAX.

BACKGROUND: Urinary tract infections (UTI) are among the most common bacterial infections and urine samples represent a large proportion of the specimens processed in clinical microbiology laboratories, up to 80% of which, however, yield negative results. Automated microscopy is widely used for urine sediment analysis and has recently been evaluated in a few studies for bacteriological screening of urine samples, achieving high levels of performance. METHODS: We present a study in which urine samples from both inpatients and outpatients, with either clean-catch or indwelling catheter urine samples, were screened for UTI by urine culture, as the reference method, and the automated urine analyser sediMAX, for the detection of bacteria, leukocytes and yeasts. RESULTS: In total, 3443 urine samples were evaluated. When a single algorithm was adopted for sediMAX to screen the total patient population, 96.4% sensitivity, 75.4% specificity, 57.8% positive predictive value, and 98.4% negative predictive value were found. However, for male outpatients and all patients with indwelling catheter other algorithms were necessary to improve performances. Altogether, with sediMAX false negative rate was 2.4% and false positive rate was 27.6%. In addition, 54% of the investigated samples could have avoided urine culture. CONCLUSIONS: After the identification of specific algorithms for different patient subgroups, the automated urine analyser sediMAX can be reliably employed in the screening of UTI.

Autogenous particulate bone collected with a piezo-electric surgical device and bone trap: a microbiological and histomorphometric study.

The aims of this study were to determine the microbiological and particle size characteristics of particulate bone collected with a piezosurgery device and bone trap, and to reduce bacterial contamination after treatment of debris with rifamycin SV. Samples were taken from 10 patients who underwent surgical extraction of their third lower molars. The ostectomy was performed with a piezosurgery device, and the debris was collected with a surgical aspiration set equipped with a bone trap. Two aliquots were taken from each sample, one of which was treated with rifamycin SV. The second aliquot, used as a control, was treated with a physiological solution. In the samples immersed in antibiotic solution, there was a statistically significant (P<0.005) reduction in bacterial contamination. The stringent protocol followed in this study has proved valid for collection of material, and treatment with rifamycin SV was found to reduce bacterial contamination in collected material.

Linezolid in the treatment of brain abscess due to Peptostreptococcus.

Brain abscesses can be caused by bacteria, fungi, and parasites. Among bacteria, anaerobic organisms include the Bacteroides species group, Fusobacterium, Peptostreptococcus, and Propionibacterium. In these cases, a 4-week course of parenteral penicillin/cefalosporin and metronidazole is the standard of treatment. We describe a case of brain abscess secondary to anaerobic infection with Peptostreptococcus, which was successfully treated with parenteral and oral linezolid after failure of standard therapy.

PEGylation of the antimicrobial peptide nisin A: problems and perspectives.

Nisin is a natural antimicrobial peptide produced by Lactococcus lactis and widely employed as food preservative. Its low solubility in neutral aqueous solutions, its instability at physiological pH and its rapid breakdown by proteolytic enzymes has limited its use for processed foods (processed cheese, milk and derivatives, canned vegetables). The conjugation to poly(ethylene glycol) (PEG) could improve its solubility and protect it towards enzymes present in non optimally processed food. We report the synthesis of a PEG-nisin conjugate, and the microbiology assays against some bacterial cell lines.