Paolo Aureli

The Enterobacter sakazakii is considered an emerging pathogen and has been recently connected to neonatal cases of necrotizing enterocolitis and meningitis due to use of contaminated powdered infant formula. However its presence is not limited to powdered infant formula; it can also be found in a broad range of foods and in water, in a variety of areas, including hospitals and houses. Due to the gravity of the infections attributed to E. sakazakii, it is necessary to introduce rigorous control measures to reduce the risks of contamination at various levels: industrial, to prevent from production to marketing the contamination of products; at a domestic level by reducing the risk of contamination, during preparation, handling, and storage, of reconstituted products; and legislative by establishing guidelines and recommendations issued by competent authorities, to guarantee the safety of infant food.

Recent genome sequencing of isolates of Listeria monocytogenes serotype 4b implicated in some major outbreaks of foodborne listeriosis has revealed unique genetic markers in these isolates. The iso...

The partial nucleotide sequence (∼10kb) of the cluster of genes encoding the botulinum neurotoxin complex in Clostridium botulinum type A strain Masc

This study was undertaken to supplement existing information on the survival of Listeria monocytogenes in Italian salami. The fact that Italian salami is frequently consumed by a large number of pe...

This paper proposes an improved high throughput microbial method for the simultaneous performance of first and second level screening for antibacterial residues in meat. It is based on growth inhibition of B. subtilis on agar medium pH 6, 7.2 and 8, of B. cereus on agar medium pH 5.9, of M. luteus on agar medium pH 8 and of E. coli on agar medium pH 7.2 (research or first level screening) and on the use of confirmatory solutions (Pase, Paba, MgSO₄) for the identification or second level screening. In kidney control samples, dialysis membranes were interposed between samples and the agar surface to both prevent the action of lysozyme and reduce false positive results. The proposed method detects β-lactams, sulfonamides, tetracyclines, aminoglycosides, macrolides and quinolones at MRL concentrations and reliably indicates the inhibitor family. Results are obtained in 18–24 h.

Herbal products on the market are evaluated by health authorities to decide whether they are drugs to all intents and purposes, and consequently they have to conform to related laws, or whether they should be regarded as dietary supplements and hence marketed freely or with notification of label to competent Authorities. The question appears to be very complicated because only a limited number of plants are utilized in phytotherapy, whereas most of them are borderline between therapeutic and physiological activity. The article summarizes the main national and community legislation on dietary supplements and herbal products.

We describe a strategy to identify the clusters of genes encoding components of the botulinum toxin type A (boNT/A) complexes in 57 strains of Clostridium botulinum types A, Ab, and A(B) isolated in Italy and in the United States from different sources. Specifically, we combined the results of PCR for detecting the ha33 and/or p47 genes with those of boNT/A PCR-restriction fragment length polymorphism analysis. Three different type A toxin gene clusters were revealed; type A1 was predominant among the strains from the United States, whereas type A2 predominated among the Italian strains, suggesting a geographic distinction between strains. By contrast, no relationship between the toxin gene clusters and the clinical or food source of strains was evident. In two C. botulinum type A isolates from the United States, we recognized a third type A toxin gene cluster (designated type A3) which was similar to that previously described only for C. botulinum type A(B) and Ab strains. Total genomic DNA from the strains was subjected to pulsed-filed gel electrophoresis and randomly amplified polymorphic DNA analyses, and the results were consistent with the boNT/A gene clusters obtained.

Denaturing high-performance liquid chromatography (DHPLC) is a recently developed technique for rapid screening of nucleotide polymorphisms in PCR products. We used this technique for the identification of type A, B, E, and F botulinum neurotoxin genes. PCR products amplified from a conserved region of the type A, B, E, and F botulinum toxin genes from Clostridium botulinum , neurotoxigenic C. butyricum type E, and C. baratii type F strains were subjected to both DHPLC analysis and sequencing. Unique DHPLC peak profiles were obtained with each different type of botulinum toxin gene fragment, consistent with nucleotide differences observed in the related sequences. We then evaluated the ability of this technique to identify botulinal neurotoxigenic organisms at the genus and species level. A specific short region of the 16S rRNA gene which contains genus-specific and in some cases species-specific heterogeneity was amplified from botulinum neurotoxigenic clostridia and from different food-borne pathogens and subjected to DHPLC analysis. Different peak profiles were obtained for each genus and species, demonstrating that the technique could be a reliable alternative to sequencing for the rapid identification of food-borne pathogens, specifically of botulinal neurotoxigenic clostridia most frequently implicated in human botulism.

Reported here is the sixth case of intestinal toxemia botulism caused by Clostridium butyricum type E in Italy since 1984. In this case, the patient was concomitantly affected with colitis due to Clostridium difficile toxin. A review of previously reported cases revealed that some of these patients may also have had intestinal toxemia botulism associated with Clostridium difficile colitis, based on the reported symptoms. Given that this association has been shown to exist not only in Italy but also in the USA, it is recommended that individuals with intestinal botulism and symptoms of colitis undergo testing for Clostridium difficile and its toxins in fecal samples.