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Objective To evaluate the ability of the probiotic strain Lactobacillus brevis CD2 to inhibit the opportunistic anaerobe Prevotella melaninogenica ( PM1), a well-known causative agent of periodontitis. Materials and Methods The inhibitory effect of Lactobacillus CD2 on Prevotella PM1 biofilm was assessed both by exposing the anaerobe to the supernatant of the probiotic strain and by growing the two strains to obtain single or mixed biofilms. The inhibitory effect of CD2 on PM1 was also checked by the agar overlay method. Results The development of PM1 biofilm was strongly affected (56% decrease in OD value) by the CD2 supernatant after 96 h. A dose-dependent biofilm reduction was also observed at 1/10 and 1/100 dilutions of supernatant. Confocal microscopy on the mixed biofilms revealed the ability of CD2 to prevail on PM1, greatly reducing the biofilm of the latter. Conclusions It has been hypothesized a multifactorial nature of the inhibition mechanism, the strong adherence ability of CD2 strain together with the released metabolites presumably contributing to the reduction in the PM1 biofilm detected by confocal microscopy. [ABSTRACT FROM AUTHOR]

In a 1-year multicenter study the microbial colonization of 1154 central venous catheters (CVCs) was investigated. Catheters explanted either from immunocompromised or immunocompetent patients were collected and analyzed by five clinical microbiology laboratories located in Ancona, Aviano, Catania, Pavia and Rome, Italy. A further aim was to investigate, by scanning electron microscopy, the features of currently used catheters, both new and explanted from patients, analyzing their surface quality, the influence of the host protein biofilm on their microbial colonization, the modifications caused by their permanence in the body and the relationship between these factors and the occurrence of infections.

The occurrence, diversity, and pathogenicity of Vibrio spp. were investigated in two estuaries along the Italian Adriatic coast. Vibrio alginolyticus was the predominant species, followed by Vibrio parahaemolyticus, non-O1 Vibrio cholerae, and Vibrio vulnificus. By using a biochemical fingerprinting method, all isolates were grouped into nine phenotypes with similarity levels of 75 to 97.5%. The production of toxins capable of causing cytoskeleton-dependent changes was detected in a large number of Vibrio strains. These findings indicate a significant presence of potentially pathogenic Vibrio strains along the Adriatic coast.

A total of 208 strains of Aeromonas were isolated by monthly sampling from two estuaries (one provided with, and the other devoid of a waste-water treatment system) on the Italian coast of the Adriatic sea between September 1994 and August 1995. Biotyping at the species level allowed the identification of 96 strains (46%) as Aer. caviae, 46 (22%) as Aer. sobria, 33 (16%) as Aer. hydrophila and 25 (12%) as Aer. veronii. Eight strains (4%) were regarded as unnamed aeromonads. Aeromonas caviae was the most prevalent species in water with a high degree of pollution, while Aer. hydrophila strains were more commonly isolated from cleaner water. Aeromonas sobria and Aer. veronii were equally distributed in both estuaries. There was no correlation between temperature and numbers of aeromonads in either estuary. Using a biochemical fingerprinting method, strains were divided into similarity groups (PhP-types) based on their biochemical phenotypes. Several different PhP-types were found in each estuary, yielding a high diversity for these strains. However, some identical PhP-types were also found in both estuaries and at different times of the year, indicating that certain Aeromonas strains can survive more widely varying physico-chemical conditions. The production of toxins capable of causing cytoskeletal-dependent changes in the morphology of Chinese hamster ovary (CHO) cells was detected in 14 strains and appeared to be dependent on the season.

One hundred and sixty-eight isolates of Escherichia coli obtained in Italy from 112 children with diarrhoea and 56 age-matched controls were examined by the HEp-2 cell adhesion assay. Sixteen strains showed localised adherence (LA), 29 showed diffuse adherence (DA) and eight strains showed aggregative adherence (AA). No adhesion pattern was significantly associated with disease. Strains that showed LA or AA were further characterised by serotyping, fluorescent actin staining (FAS) test and hybridisation with the EPEC adherence factor (EAF), E. coli attaching and effacing (eae) and enteroaggregative (EAgg) DNA probes. Strains that showed poor LA were FAS-negative, did not belong to EPEC serotypes and did not hybridise with EPEC probes. Conversely, the two strains that showed a good LA pattern belonged to serotype O128:H2, were FAS positive and hybridised with the eae probe. No isolate hybridised with the EAF probe. Only three of the eight strains with the AA pattern hybridised with the EAgg probe. Probe positivity correlated with the ability to produce clumps at the surface of the liquid culture and to agglutinate rat erythrocytes. In two of these EAgg probe-positive strains, electronmicroscopy revealed the presence of fibrillar bundles which seem to mediate bacterial aggregation.

Escherichia coli strains isolated from 81 fecal samples from red deer (Cervus elaphus), roe deer (Capreoulus capreoulus), chamois (Rupicapra rupicapra) and alpine marmot (Marmota marmota) living in the Stelvio National Park, Italy, were examined for antimicrobial resistance and production of toxic factors. Direct plating of specimens on media containing antimicrobial drugs allowed us to isolate resistant strains of E. coli from 10 of 59 (17%) specimens examined by this technique. Nine of 31 specimens from red deer (29%) contained resistant strains. Different animals were likely colonized by the same resistant strain of E. coli. Conjugative R plasmids were found in four strains isolated from the marmot, roe deer and chamois. A strain from red deer produced heat-stable enterotoxin and another strain produced both hemolysin and cytotoxic necrotizing factor. A marmot isolate produced hemolysin alone. No strains were found to produce heat-labile enterotoxin or verotoxins.

Three cytopathic rotavirus isolates were recovered from young rabbits affected by an enteric syndrome. The three isolates, when compared by cross serum-neutralization tests, were found to be of the same serotype. Cross neutralization occurred also between a representative of the rabbit isolates and one strain of bovine rotavirus.

Nine strains of ETEC isolated in Italy have been compared with 13 isolates from Somalia with respect to toxin production, serotype and antimicrobial resistance pattern. None of the strains isolated from Italy belonged to any serotype or serogroups found among the strains from Somalia. Remarkable differences between the two groups of isolates were also observed with regard to the susceptibility to antimicrobials and the presence of R-plasmids. These findings suggest that ETEC strains isolated in Italy are not related to the strains widespread in Somalia and, generally, in developing countries.

We have undertaken a study on 200 autopsy lung samples collected from subjects who lived in the Rome urban area and were not occupationally exposed to mineral dusts. The samples belonged to subjects who died aged between 15 and 65, both male and female. Subjects suffering from diseases and drug addicts were excluded. The purpose of this investigation was to determine whether any correlation existed between subjects' life-style, in particular smoking habits, and the presence of mineral fibres and dusts in their lungs. The data obtained were compared with those on airborne mineral dusts in the environment of the subjects themselves, particularly data on the concentration and types of mineral fibres present in that environment.

We studied the inorganic particulate contained in the lung parenchyma of 10 subjects (5 males and 5 females) resident in an urban area and not occupationally exposed to dusts. A total of 17 mineral types were identified, along with 16 metal elements in the form of oxides and sulfides. Approximately 70% of the minerals were made up of phyllosilicates, in particular clay, mica, and talc; three metal elements, Fe, Al, and Ti, accounted for more than 75% of the recovered oxide particles. The mean concentration of the observed inorganic particles was approximately 1.8 X 10(5) pp/mg dry tissue. No significant differences were observed in terms of total particulate concentration in the various areas of the lungs and between the right and left lung. Instead we observed a larger concentration of fibrous particles in the upper lobes. The analysis of the data made it possible to determine the presence of a high degree of correlation between the concentrations of silicates and the concentrations of metal oxides and sulfides, implying the existence of a ubiquitous environmental source of these mineral particles. The frequent observation of tremolite fibers is remarkable. This finding, confirmed elsewhere, indicates that the magnitude of the sources of these fibers in the environment, constituted by contaminated talc dusts, has been underestimated until today.

Cryptosporidium oocysts were observed in the stools of 9 (7.2%) of 124 Italian children with diarrhoea, examined during the period 1 January-31 December 1984. In two children, the parasite was associated with other enteric pathogens. The duration of diarrhoea was 2-30 days, with a median of 6 days. In all cases the infection was self limiting. The mean age of the Cryptosporidium-positive children was 34 months, and all cases occurred in the warm season. Cryptosporidium was found to be the third most common enteric pathogen after rotavirus and Salmonella spp.