Unusual species of campylobacters isolated in the Siena Tuscany area, Italy.
Musmanno RA. Russi M. Figura N. Guglielmetti P. Zanchi A. Signori R. Rossolini A.
Dipartimento di Biologia Molecolare, Universita degli Studi, Siena, Italy.
From January 1989 to December 1990, stool samples from 288 children with enteritis were examined for the presence of unusual campylobacters which represented about 20% of all campylobacteria isolated when the filtration technique was used. The isolation percentage was the following: C. jejuni ss. jejuni 6.9%; C. coli 2%; C. jejuni ss. doylei, C. upsaliensis and C. concisus each 0.7%. The atypical Campylobacter isolates were examined for their virulence characteristics. Toxin profiles based on cytotonic, cytotoxic and cytolethal distending factors were determined after analysis responses in Vero, CHO and HeLa cells. Adhesivity and invasivity tests were performed on Intestine 407 cells. No strain was cytotoxic. C. jejuni ss. doylei and C. concisus induced an elongation of CHO cells (a cytotonic-like effect). C. upsaliensis strains provoked a cytolethal distending effect. No strain adhered to cells in vitro. Our results suggest that the filtration technique is excellent for the isolation of atypical campylobacters and indicate that the unusual Campylobacter isolates could be potentially virulent.
Virulence factors in Aeromonas spp and their association with gastrointestinal disease.
Schiavano GF. Bruscolini F. Albano A. Brandi G.
Institute of Toxicologic Hygienic and Environmental Science, University of Urbino, Italy.
Culture filtrates of eight Aeromonas strains isolated from the feces of 487 subjects (292 diarrhoeic patients and 195 asymptomatic subjects) were tested for toxin production in CHO and McCoy cells, and adhesion and invasive ability in Caco-2 cells. Among these isolates, three Aeromonas sobria and one Aeromonas caviae strains possessed virulence-associated properties. Toxin production was the most common of the three virulence properties. Two A. caviae were associated, in the absence of other diarrhoeagenic agents, with gastroenteritis; however, a virulence marker (cytotoxin) was recognized only in one strain. Two strains of A. sobria isolated from subjects with gastroenteritis were shown to be associated with one (cytotoxicity) or two (adhesion and invasive abilities) virulence factors, respectively. However, a third strain of A. sobria, although cytotoxic and invasive, was isolated from an asymptomatic subject. The results show that Aeromonas spp may act as human enteric pathogens, but also indicate that the significance of several putative virulence factors, such as production of cytotoxin and the capacity to adhere to and invade mammalian cells, remains controversial in explaining the enteropathogenesis of Aeromonads and therefore needs further studies.
Comparative analysis of two systems for HCV genotyping.
Di Girolamo A. D'Antonio D. Parruti G. Iacone A. Di Gianfilippo R. Salemme L. Pizzigallo E.
Clinic of Infectious Diseases, G. D'Annunzio University, Chieti, Italy.
The HCV genotype can be determined by PCR using nested primers to structural or non-structural HCV regions, followed by hybridization analysis of the amplified products. In this study, two different systems, both based on PCR and hybridization analysis, were used to determine HCV genotype in 32 HCV positive patients at the Clinic of Infectious Diseases, University of Chieti. The main difference between these commercially available systems lies in the different PCR target. Amplification of PCR targets was obtained from all samples. Hybridization analysis gave unequivocal results for all samples with both methods, yielding a 100% rate of genotype determination, with a complete correlation at the genotype level. A lower concordance at subtype level (65% concordance) was found, due only to two types of discrepancies. Both methods proved easy to use in our hands, adding evidence to their potential usefulness and reliability in clinical settings.