Direct maldi-tof mass spectrometry assay of blood culture broths for rapid identification of Candida species causing bloodstream infections: an observational study in two large microbiology laboratories.

We evaluated the reliability of the Bruker Daltonik's MALDI Biotyper system in species-level identification of yeasts directly from blood culture bottles. Identification results were concordant with those of the conventional culture-based method for 95.9% of Candida albicans (187/195) and 86.5% of non-albicans Candida species (128/148). Results were available in 30 min (median), suggesting that this approach is a reliable, time-saving tool for routine identification of Candida species causing bloodstream infection.

Limited usefulness of QuantiFERON-TB Gold In-Tube for monitoring anti-tuberculosis therapy.

The usefulness of IFN-gamma release assays to monitor the efficacy of anti-tuberculosis (TB) treatment is controversial. Sixty patients affected by culture-confirmed pulmonary TB (M = 36; mean age: 39.2 yr; Italians = 28) were serially tested in a low prevalence setting by means of QuantiFERON-TB GOLD In-Tube (QFT-IT) at baseline and after a successful six-month therapy regimen (T6). A sub-group of 40 cases was also tested at 1 and 3 months. Overall, 88.3% of patients scored a QFT-IT positive result at baseline, with the higher proportion of TB-specific IFN-gamma responses in foreign-born patients (p = 0.04). TB-specific responses were highly variable over time, the within-person variability being correlated with baseline IFN-gamma levels (r = 0.731; p < 0.001). Overall, 61.6% of cases still tested QFT-IT positive at the completion of therapy. Average IFN-gamma levels increased over time, being persistently significantly higher in Italian patients than in foreign-born cases both at baseline (p = 0.03) and at T6 (p = 0.02). Reversion mainly occurred in patients (26.6%) with baseline IFN-gamma levels close to the conventional cut-off value. No indeterminate results were recorded at any study time point. In conclusion, QFT-IT adds no significant information to clinicians for treatment monitoring when applied in routine clinical practice in a low prevalence setting. Kinetics of T cell responses upon TB treatment and reversion (and conversion) thresholds need to be addressed. Diversity of IFN-gamma responses among patients of different geographic origin is an issue to be investigated further.

An uncommon presentation for a severe invasive infection due to methicillin-resistant Staphylococcus aureus clone USA300 in Italy: a case report.

BACKGROUND: Methicillin resistant Staphylococcus aureus (MRSA) has been considered for many years a typical nosocomial pathogen. Recently MRSA has emerged as a frequent cause of infections in the community. More commonly, community-acquired (CA)-MRSA is a cause of infections of the skin and soft-tissues, but life-threatening infections such as necrotizing pneumonia and sepsis can occasionally occur. CASE PRESENTATION: This report describes an uncommon presentation of invasive CA-MRSA infection in an adolescent without known risk factors. The presentation was typical for bacterial meningitis, but the clinical findings also revealed necrotizing pneumonia. Following the development of deep venous thrombosis, the presence of an inherited thrombophilic defect (factor V Leiden) was detected. The patient was successfully treated with an antibiotic combination including linezolid and with anticoagulant therapy. CA-MRSA was isolated from both cerebrospinal fluid and blood. The isolates were resistant to oxacillin and other beta-lactam antibiotics and susceptible to the other antibiotics tested including erythromycin. Molecular typing revealed that the strains contained the Panton-Valentine leukocidin genes and type IV SCCmec, and were ST8, spa type t008, and agr type 1. This genetic background is identical to that of the USA300 clone. CONCLUSION: This report highlights that meningitis can be a new serious presentation of CA-MRSA infection. CA-MRSA strains with the genetic background of the USA300 clone are circulating in Italy and are able to cause severe infections.

Multicenter evaluation of mycobacteria growth indicator tube (MGIT) compared with the BACTEC radiometric method, BBL biphasic growth medium and Löwenstein---Jensen medium.

OBJECTIVE: To evaluate the new BBL mycobacteria growth indicator tube (MGIT) in comparison with other media. METHODS: MGIT was evaluated in 10 Italian centers on 433 clinical samples, mainly of respiratory origin and mainly smear positive, in comparison with Löwenstein---Jensen and with one or more other methods represented, according to participating centers, by the BACTEC radiometric method or by the biphasic BBL Septi-Chek AFB system. While MGIT and Löwenstein---Jensen were used for all the samples, 285 of them were also inoculated in BACTEC vials and 274 in biphasic bottles. Of these samples, 132 were investigated with all the four methods. RESULTS: Although less rapid and sensitive than the radiometric method, the results of MGIT were equal when compared with the other two media with respect to overall isolation yield; furthermore, it allowed the detection of growth in significantly shorter times. CONCLUSIONS: The results of this study indicate the value of MGIT for the detection of mycobacteria and, thanks to its extreme simplicity of use, its suitability for small and large laboratories. Its combined use with a solid medium can substantially improve the diagnosis of mycobacterial infection.