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P Aureli

Publications and source records attributed to P Aureli.

At least 19 recordsLinked to original sources
PubMed2006

Combined Plate Microbial Assay (CPMA): a 6-plate-method for simultaneous first and second level screening of antibacterial residues in meat.

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 beta-lactams, sulfonamides, tetracyclines, aminoglycosides, macrolides and quinolones at MRL concentrations and reliably indicates the inhibitor family. Results are obtained in 18-24 h.

Agar↗
PubMed2006

Listeriosis associated with gorgonzola (Italian blue-veined cheese).

We describe a case of listeriosis in Italy associated with the consumption of cheese. Opened samples of two brands of gorgonzola (Italian blue-veined cheese; referred to as brands "B" and "C") were collected from the patient's refrigerator. Unopened samples of the brand suspected to be the source of infection (brand B) were taken from the store where the cheese had been purchased, other local stores, and the production plant. Listeria monocytogenes serotype 1/2b was isolated from the patient and from the opened and unopened cheese samples. The contamination level varied from <100 to 1,200 cfu g(-1). Molecular typing of the isolates, using both randomly amplified polymorphic DNA (RAPD) and pulsed-field gel electrophoresis (PFGE), demonstrated that the isolates from the patient's refrigerator, food stores, and production-plant samples were indistinguishable from the clinical isolate. Molecular typing verified the peristence of closely related L. monocytogenes isolates in the production plant B for 5 months. The results stress the importance of developing a code of hygienic practice for preventing, limiting, and where possible, eliminating this pathogen in processed foods and of educating at-risk persons on foods likely to be contaminated.

Bacterial Typing Techniques↗
PubMed2006

Survival of Listeria monocytogenes in uncooked Italian dry sausage (salami).

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 people poses some serious health implications. Some raw materials have been found to be microbiologically contaminated, for their production occurs without any thermic treatment, and these are in circulation throughout Italy all year round. We selected the product for its microbiological, technological, and commercial characteristics. We analyzed 1,020 samples taken during the autumn and winter 2002 and spring and summer 2003 periods and immediately before selling. The samples were collected from 17 plants with an annual production of between 1 and 2000 metric tons and with a distribution of products in over 80% of Italy in geographic terms. To detect and enumerate L. monocytogenes, we followed International Organization for Standardization (ISO) 11290 part 1 and 2: 1996 (modified using chromogenic medium Agar Listeria according to Ottarviani and Agosti [ALOA]). L. monocytogenes was found in 22.7% of samples, but the contamination level was less than 10 CFU/g. Contamination prevalence ranged from 1.6 to 58.3% and was lower than 10% in 5 of the 17 plants checked. The most frequently isolated serotypes were 1/2c, 1/2a, 1/2b, and 4b. Additional studies are necessary to establish if the exposure to a small number of L. monocytogenes cells through the consumption of salami represents a significant health risk and, in light of the future introduction of the SANCO/4198/2001 revision 21 "Commission Regulation on Microbiological Criteria for Foodstuffs," is a necessary investigation.

Animals↗
PubMed2003

Antimycotic activity of Melaleuca alternifolia essential oil and its major components.

AIMS: The aim of this study was to analyse the antimycotic properties of Melaleuca alternifolia essential oil (tea tree oil, TTO) and its principal components and to compare them with the activity of 5-fluorocytosine and amphotericin B. METHODS AND RESULTS: The screening for the antimycotic activity was performed by serial twofold dilutions in Roswell Park Memorial Institute medium with the inclusion of Tween-80 (0.5%). TTO and terpinen-4-olo were the most active compounds. CONCLUSIONS: The majority of the organisms were sensitive to the essential oil, with TTO and terpinen-4-olo being the most active oils showing antifungal activity at minimum inhibitory concentration values lower than other drugs. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides a sample large enough to determine the antifungal properties of TTO and terpinen-4-olo and suggests further studies for a possible therapeutic use.

Amphotericin B↗
PubMed2002

A case if infant botulism due to neurotoxigenic Clostridium butyricum type E associated with Clostridium difficile colitis.

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.

Anti-Bacterial Agents↗
PubMed2002

Interactions between novel micro-organisms and intestinal flora.

Microbial strains traditionally used to ferment food have a long history of safe use and are, therefore, considered as generally recognised as safe. Many of these micro-organisms have also functional attributes and are included among probiotics. New species and strains of bacteria with desirable technological and functional properties are constantly being identified; in addition, micro-organisms can be engineered by recently developed biotechnological tools in order to accelerate strain improvement. Although the potentialities of novel micro-organisms with better probiotic and technological properties are promising, it cannot be assumed that they share the safety record of traditional micro-organisms, since they may pose unique challenges for human health. The risk assessment and safety evaluation of novel micro-organisms must focus, primarily, on their potential harmful effects, both direct and indirect, upon host resident intestinal microflora. Genetically modified micro-organisms need further assessment for the complete characterisation of the DNA rearrangement and of the final product, in order to establish the "substantial equivalence" with the parental strain.

Fermentation↗
PubMed2001

Characterization of Listeria monocytogenes strains involved in invasive and noninvasive listeriosis outbreaks by PCR-based fingerprinting techniques.

A total of 32 Listeria monocytogenes strains (16 from a recent outbreak of invasive listeriosis and 16 from two outbreaks of noninvasive listeriosis, all three occurring in Italy) were characterized by PCR-ribotyping, arbitrarily primed PCR (AP-PCR), and the recently developed infrequent-restriction-site PCR (IRS-PCR). The discriminatory ability of the techniques, first evaluated on 29 unrelated L. monocytogenes food isolates using Simpson's index of diversity, was 0.714 for PCR-ribotyping, 0.690 for AP-PCR, and 0.919 for IRS-PCR. IRS-PCR was also more capable of distinguishing among strains from the invasive listeriosis outbreak: three different clusters were identified by IRS-PCR compared to two clusters identified by both PCR-ribotyping and AP-PCR. Within each of the two outbreaks of noninvasive listeriosis, the patterns were practically identical, as demonstrated by all three techniques. Only IRS-PCR succeeded in clearly discriminating the strains related to noninvasive listeriosis from all of the other strains included in this study, including those from the outbreak of invasive listeriosis. This finding may suggest the presence of unique differences in their DNA sequences.

Animals↗
PubMed2000

An outbreak of febrile gastroenteritis associated with corn contaminated by Listeria monocytogenes.

BACKGROUND: On May 21, 1997, numerous cases of febrile gastrointestinal illness were reported among the students and staff of two primary schools in northern Italy, all of whom had eaten at cafeterias served by the same caterer. METHODS: We interviewed people who ate at the cafeterias about symptoms and foods consumed on May 20. There were no samples of foods left at the cafeterias, but we tested routine samples taken on May 20 by the caterer and environmental specimens at the catering plant. The hospitalized patients were tested for common enteropathogens and toxins. RESULTS: Of the 2189 persons interviewed (82 percent of those exposed), 1566 (72 percent) reported symptoms; of these, 292 (19 percent) were hospitalized. Among samples obtained from hospitalized patients, all but two of the stool specimens and all blood specimens were negative for common enteropathogens. Listeria monocytogenes was isolated from one blood specimen and from 123 of the 141 stool specimens. Consumption of a cold salad of corn and tuna was associated with the development of symptoms (relative risk, 6.19; 95 percent confidence interval, 4.81 to 7.98; P<0.001). L. monocytogenes was isolated from the caterer's sample of the salad and from environmental specimens collected from the catering plant. All listeria isolates were serotype 4b and were found to be identical on DNA analysis. Experimental contamination of sterile samples of the implicated foods showed that L. monocytogenes grew on corn when kept for at least 10 hours at 25 degrees C. CONCLUSIONS: Food-borne infection with L. monocytogenes can cause febrile illness with gastroenteritis in immunocompetent persons.

Adult↗
PubMed2000

An outbreak in Italy of botulism associated with a dessert made with mascarpone cream cheese.

In the late 1996, an outbreak of botulism affected eight young people (age of patients ranged from 6 to 23 years) in Italy. The onset of the illness was the same for all of these patients: gastrointestinal symptoms (nausea and vomiting) followed by neurologic symptoms. The most common neurologic symptoms were dysphagia, respiratory failure (100%), diplopia (87%), dysarthria, ptosis (75%) and mydriasis (50%). All patients required mechanical ventilation. Botulinum toxin was detected from two of respectively five sera and six stool samples analysed, while spores of Clostridium botulinum type A were recovered from all patient' faeces. The epidemiological investigation led to suspect a commercial cream cheese ('mascarpone') as a source of botulinum toxin: indeed, it had been eaten by all the patients before onset of the symptoms, either alone or as the (uncooked) ingredient of a dessert, 'tiramisù'. Botulinum toxin type A was found in the 'tiramisù' leftover consumed by two patients and in some mascarpone cheese samples collected from the same retail stores where the other patients had previously bought their cheeses. A break in the cold-chain at the retail has likely caused germination of C. botulinum spores contaminating the products, with subsequent production of the toxin. One of the patients died, while the others recovered very slowly. Prompt international alerting and recall of the mascarpone cheese prevented the spread of the outbreak due to the wide range of distribution, demonstrating the importance of a rapid surveillance system. None of the people complaining of symptoms after the public alert resulted positive for botulinum spores and toxin.

Adolescent↗
PubMed2000

In vivo and in vitro assessment of the virulence of Listeria monocytogenes strains.

To evaluate whether the in vitro model (invasion and intracellular growth in Caco-2 cells) for determining virulence is a suitable alternative to the in vivo model (50% lethal dose), we compared the levels of virulence obtained with the two models. We tested L. monocytogenes strains isolated from food and clinical samples during three episodes of listeriosis occurring in Italy in the period 1993-1995. We also tested L. monocytogenes strains isolated from food during official control activities. The results obtained from the tested strains varied according to the experimental method adopted: the L. monocytogenes strains featuring the same genetic pattern showed a greater uniformity of response in vivo than in vitro. We can conclude that the in vitro model may be used as an alternative to the animal model to determine Listeria spp pathogenicity, though it cannot distinguish levels of virulence within the L. monocytogenes species.

Animals↗
PubMed1999

Intestinal toxemia botulism in two young people, caused by Clostridium butyricum type E.

Two unconnected cases of type E botulism involving a 19-year-old woman and a 9-year-old child are described. The hospital courses of their illness were similar and included initial acute abdominal pain accompanied by progressive neurological impairment. Both patients were suspected of having appendicitis and underwent laparotomy, during which voluminous Meckel's diverticula were resected. Unusual neurotoxigenic Clostridium butyricum strains that produced botulinum-like toxin type E were isolated from the feces of the patients. These isolates were genotypically and phenotypically identical to other neurotoxigenic C. butyricum strains discovered in Italy in 1985-1986. No cytotoxic activity of the strains that might explain the associated gastrointestinal symptoms was demonstrated. The clinical picture of the illness and the persistence of neurotoxigenic clostridia in the feces of these patients suggested a colonization of the large intestine, with in vivo toxin production. The possibility that Meckel's diverticulum may predispose to intestinal toxemia botulism may warrant further investigation.

Adult↗
PubMed1999

Clostridium botulinum spores and toxin in mascarpone cheese and other milk products.

A total of 1,017 mascarpone cheese samples, collected at retail, were analyzed for Clostridium botulinum spores and toxin, aerobic mesophilic spore counts, as well as pH, a(w) (water activity), and Eh (oxidation-reduction potential). In addition 260 samples from other dairy products were also analyzed for spores and botulinum toxin. Experiments were carried out on naturally and artificially contaminated mascarpone to investigate the influence of different temperature conditions on toxin production by C. botulinum. Three hundred and thirty-one samples (32.5%) of mascarpone were positive for botulinal spores, and 7 (0.8%) of the 878 samples produced at the plant involved in an outbreak of foodborne botulism also contained toxin type A. The chemical-physical parameters (pH, a(w), Eh) of all samples were compatible with C. botulinum growth and toxinogenesis. Of the other milk products, 2.7% were positive for C. botulinum spores. Growth and toxin formation occurred in naturally and experimentally contaminated mascarpone samples after 3 and 4 days of incubation at 28 degrees C, respectively.

Bacteria↗
PubMed1998

Genetic typing of human and food isolates of Listeria monocytogenes from episodes of listeriosis.

Ten clinical and food Listeria monocytogenes strains isolated during the epidemiological investigations of episodes of listeriosis (one outbreak and two sporadic cases) that occurred in northern Italy during 1993-1995 have been examined by DNA macrorestriction pattern analysis obtained by PFGE and RAPD typing, in order to confirm the food vehicle of infections. The same DNA profiles within the isolates from the three episodes were obtained by both techniques. The Apal and Smal PFGE profiles and RAPD patterns with primer OPM-01 confirmed the close relationship between strains from two distinct episodes. However, RAPD analysis with primer UBC-127 distinguished between these L. monocytogenes isolates.

Adult↗
PubMed1998

The detection of a deletion in the type B neurotoxin gene of Clostridium botulinum A(B) strains by a two-step PCR.

Differences between the type B neurotoxin gene sequence of Clostridium botulinum type A(B) and Cl. botulinum type B, including a six nucleotide deletion, were recently proposed as a cause of the lack of expression of this gene in the type A toxigenic strains. A polymerase chain reaction (PCR) based on two sets of primers was designed to investigate the absence of the 6-nucleotide sequence in the apparently unexpressed type B toxin gene of 42 strains of Cl. botulinum type A(B). Thirty-five strains were shown to exhibit a deletion in their type B toxin gene; two strains did not have the deletion and actually produced small amounts of type B toxin when tested by the mouse bioassay. This two-step PCR might be useful for the rapid determination of the presence of the six nucleotide deletion and consequently, whether the type B toxin is likely to be produced.

Animals↗
PubMed1997

Recovery of a strain of Clostridium botulinum producing both neurotoxin A and neurotoxin B from canned macrobiotic food.

A rare strain of Clostridium botulinum subtype Ab was isolated from a canned macrobiotic food suspected of being linked to a fatal case of food-borne botulism. The strain was recovered and identified by conventional methods modified by the inclusion of a PCR assay (G. Franciosa, J.L. Ferreira, and C.L. Hatheway, J. Clin. Microbiol. 32:1911-1917, 1994). The titers of neurotoxins produced by the strain were evaluated by a mouse bioassay.

Aged↗