The answer of the Bacteriology Laboratory to new clinical needs. Rapid sepsis diagnotics at the Novara hospital

Faster microbiological responses are increasingly necessary in modern medicine and the Laboratory of Microbiology must be equipped in this sense. New instrumentation and, above all, a new approach by the Clinical Microbiologist that puts a focus on the real needs of the patient before the microbiological may allow for significantly improving the TAT of these diagnostics. The use of both new methodologies, new tools and revisited old technologies may mean less these days as it was obtained at the Laboratory of Microbiology and Virology of Novara, where the combined use of molecular biology techniques, and mass spectrometry techniques rapid growth have allowed for more than 36 hours to shorten the response time by positivization of blood cultures. Such an approach allows an important support to the clinician with obvious benefits for the patient

Direct identification of bacteria in blood culture by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry: a new methodological approach

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has recently been demonstrated to be a powerful tool for the rapid identification of bacteria from growing colonies. In order to speed up the identification of bacteria, several authors have evaluated the usefulness of this MALDI-TOF MS technology for the direct and quick identification bacteria from positive blood cultures. The results obtained so far have been encouraging but have also shown some limitations, mainly related to the bacterial growth and to the presence of interference substances belonging to the blood cultures. In this paper, we present a new methodological approach that we have developed to overcome these limitations, based mainly on an enrichment of the sample into a growing medium before the extraction process, prior to mass spectrometric analysis. The proposed method shows important advantages for the identification of bacterial strains, yielding an increased identification score, which gives higher confidence in the results. Copyright © 2011 John Wiley & Sons, Ltd

Identification using Matrix-Assisted Laser Desorption Ionization Time-Of-Flight Mass Spectrometry: Preliminar Data

Bacterial identification is usually allowed analyzing the phenotypic and biochemical topics of microorganisms. The traditional methods of identification require about 18-24 hours and are expensive. Matrix-Assisted Laser Desorption Ionization Time-Of-Flight Mass Spectrometry (MALDI-TOF MS) allows the identification of bacteria in few minutes. We consider 459 bacterial strains that were identified both with MALDI TOF MS and VITEK-2. The percentage of concordance in every group of bacteria was more than 99%, at genus level were more than 94% and at species level was more than 92%. These preliminary data show that MALDI-TOF MS allows a rapid and precise microorganism identification

Rapid tests: preliminar identification from blood culture

In the period 1 April to 30 June 2011, we compared the rapid test identification of 250 positive blood cultures with the identification by MALDI-TOF mass spectrometer (Bruker). After Gram staining and an important step in HB&L liquid culture (Alifax), rapid tests were performed according to the morphological characteristics of the sample. Pneumococcus urinary antigen test and tube coagulase test showed a concordance of 100%, the concordance rates for Pyr test and oxidase test were 91% and 89% respectively. Overall, the percentage of agreement of the rapid tests on 250 samples was found to be of 99.2%. The data obtained show that, even with their increased bacterial concentration due to the enrichment step in HB&L liquid culture, it is possible to obtain preliminary identification directly from positive blood culture with simple rapid tests

Direct identification from Bact/Alert™ blood culture bottles by MALDI-TOF

Bacterial identification from blood culture using traditional methods needs about 48 hours, since positivization, to be performed. Rapid bacterial identification can result in clinical and economic benefits. To provide rapid pathogen identification for targeted antibiotic treatment, in this study we tested an our previously described homemade method for bacterial identification using MALDI-TOF directly from positive BACTEC blood culture, on positive BacT/ALERT blood culture. A total of 108 bacteria were identified by MALDI-TOF with a positive identification obtained for 98% of Gram negative and 84,3% of Gram positive bacteria.The average of identification score obtained using the protocol described in this study was 2,047 for Gram positive and 2,204 for Gram negative microorganisms. Data here described show that this method is also useful when BacT/ALERT bottles are used and even if these bottles have activated charcoal as inhibitor of antibiotics

Preliminary indications for antibiotic susceptibility tests in less than six hour in positive blood cultures

A rapid determination of the antibiotic susceptibility patterns of pathogens responsible for sepsis represents a significant milestone for a timely correct antibiotic therapy.The system HB&L® (ALIFAX) allows reduced time in the detection of bacterial growth and consequently is able to detect the growth or absence of certain microorganisms in the presence of a given antibiotic. In this study three system for rapid antibiotic susceptibility tests among bacteria isolated from blood were compared: HB&L® (ALIFAX),VITEK®2 (bioMérieux) and essays Etest® (bioMérieux). Present findings indicate that HB&L® (ALIFAX) is rapid reliable instrument that may support the clinician for a rapid and appropriate treatment, particularly in the critical patient

Global Justice: current situation and new challenges

The issue addresses the question of global justice, its many interpretations and possible doctrines, as well as its links with important global issues such as climate change and inequality