Internalin A (InlA), a cell wall-bound protein of Listeria monocytogenes, is among the major components involved in the adhesion to and invasion of host cells expressing specific forms of E-cadherin. Some L. monocytogenes strains secrete truncated non-functional forms of InlA. The purpose of this study is to compare the biofilm-forming abilities of L. monocytogenes strains from clinical sources expressing InlA proteins in the different forms. A total of 70 L. monocytogenes strains were examined using SDS-PAGE, Western blot, DNA sequencing, and microtitre plate biofilm formation assays. We found that 8 of the 70 strains expressed truncated InlA, and that this group of strains exhibited significantly enhanced biofilm-forming ability compared to the group expressing full-length InlA. Further experiments showed that: (i) L. monocytogenes biofilms were detached by treatment with protease K; (ii) protein fragments resulting from proteolysis, rather than intact proteins, are responsible for biofilm enhancement, because biofilm formation was impaired by the protease inhibitor alpha2-macroglobulin; (iii) truncated and/or proteolytically cleaved InlA are likely involved in the biofilm enhancement, based on the effects that anti-InlA monoclonal antibodies produced on the biofilm formation of L. monocytogenes strains expressing either truncated or full-length InlA. These data provide a basis for further investigation of the molecular structure and composition of L. monocytogenes biofilms.

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.

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A multicenter one-year study was carried out on 6629 headache patients under 18 years of age, attending 27 centers and clinics devoted to headache in Italy to identify the prevalence of cluster headache (CH) in childhood and adolescence. Two male CH patients aged 9 and 17 years were identified. Their attacks fulfilled the IHS criteria for CH, and they were classified as having cluster headache with undetermined periodicity and episodic cluster headache, respectively. The one-year prevalence in this headache out-patient population under 18 years of age was calculated to be 0.03%. This value is smaller than that derived in the general population. This finding further confirms the rarity of early diagnosis of this primary disorder in childhood and adolescence, as demonstrated in other studies.

Headache, and in particular migraine, is a common disturbance in childhood and adolescence. The disabling nature of headache, evident in the adult, together with its effects on family life and reduction in performance of scholastic activity, make it a disease with an elevated social economic impact. We present preliminary results of a prospective study conducted over 6 months on a population of headache sufferers in childhood and adolescence who referred to our Juvenile Neuropsychiatry Centre of the Hospital of Perugia. Our objective was to quantify the direct and indirect costs associated with juvenile headache.