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C Pruzzo

Publications and source records attributed to C Pruzzo.

At least 19 recordsLinked to original sources
PubMed2007

Comparison of different biochemical and molecular methods for the identification of Vibrio parahaemolyticus.

AIMS: Multicentre evaluation of biochemical and molecular methods for the identification of Vibrio parahaemolyticus. METHODS AND RESULTS: For the biochemical identification methods, API 20E and API 20NE and Alsina's scheme were evaluated in intra- and interlaboratory tests in order to determine the accuracy and concordance of each method. Both in intra- and interlaboratory tests, the Alsina's scheme showed the highest sensitivity (86% of correct identifications in the interlaboratory test). False-positive results were obtained by all methods (specificity was 95% for API 20E, 73% for API 20NE and 84% for Alsina's scheme) and concordance varied from 65% of API 20NE to 84% of API 20E. For the molecular identifications, polymerase chain reaction (PCR) for the detection of toxR gene, tl gene and pR72H fragment were tested on 30 strains by two laboratories. The PCR for toxR showed the highest inclusivity (96%), exclusivity (100%) and concordance (97%). CONCLUSIONS: Among the biochemical identification methods tested, the Alsina's scheme gave more reliable results; however, in order to avoid false-positive results, all the biochemical identifications should be confirmed by means of molecular methods. SIGNIFICANCE AND IMPACT OF THE STUDY: Availability of an efficient identification method of Vibrio parahaemolyticus to use in official control of fisheries products.

Bacterial Proteins↗
PubMed2005

Molecular vs culture methods for the detection of bacterial faecal indicators in groundwater for human use.

AIMS: The current standard culture methods are unable to detect nongrowing bacteria and, thus, might not be sufficient for precise monitoring of the microbiological quality of waters. The use of a molecular method such as PCR could be a valid alternative to detect bacterial faecal contamination indicators such as Escherichia coli and Enterococcus faecalis and reveal the presence of culturable and nonculturable bacterial forms. METHODS AND RESULTS: The presence of E. coli and Ent. faecalis cells in 30 groundwater samples was evaluated with the standard culture method and compared with a specific PCR protocol. A substantial percentage (50%) of the samples not containing culturable cells proved positive in the search for Ent. faecalis DNA by PCR. Quantification by competitive PCR (cPCR) of the DNA detected allowed us to calculate the number of nonculturable cells present in water samples: the number varied from 2 to 120 cells ml(-1). Only four samples were positive for E. coli DNA and the corresponding nonculturable cells varied from 24 to 70 ml(-1). CONCLUSIONS: This study demonstrates that the standard culture methods in use are unable to detect a substantial proportion of the bacterial population which is nonculturable but, as previously demonstrated, potentially still viable and able to express those pathogenic factors needed for causing infections in humans. SIGNIFICANCE AND IMPACT OF THE STUDY: To protect human health it is necessary to develop and use methods which detect the nonculturable as well as culturable bacteria present in water.

Bacteriological Techniques↗
PubMed2002

Antiadhesive effect of green and roasted coffee on Streptococcus mutans' adhesive properties on saliva-coated hydroxyapatite beads.

Green and roasted coffees of the two most used species, Coffea arabica and Coffea robusta, several commercial coffee samples, and known coffee components were analyzed for their ability to interfere with Streptococcus mutans' sucrose-independent adsorption to saliva-coated hydroxyapatite (HA) beads. All coffee solutions showed high antiadhesive properties. The inhibition of S. mutans' adsorption to HA beads was observed both when coffee was present in the adsorption mixture and when it was used to pretreat the beads, suggesting that coffee active molecules may adsorb to a host surface, preventing the tooth receptor from interacting with any bacterial adhesions. Among the known tested coffee components, trigonelline and nicotinic and chlorogenic acids have been shown to be very active. Dialysis separation of roasted coffee components also showed that a coffee component fraction with 1000 Da < MW < 3500 Da, commonly considered as low MW coffee melanoidins, may sensibly contribute to the roasted coffee's antiadhesive properties. The obtained results showed that all coffee solutions have antiadhesive properties, which are due to both naturally occurring and roasting-induced molecules.

Bacterial Adhesion↗
PubMed2001

Surface interactions between Escherichia coli and hemocytes of the Mediterranean mussel Mytilus galloprovincialis lam. leading to efficient bacterial clearance.

The role of type 1 fimbriae in the interactions between Escherichia coli and Mytilus galloprovincialis Lam. hemocytes was evaluated. The association of fimbriated strain MG155 with hemocyte monolayers at 18 degrees C was 1.5- and 3- to 4-fold greater than the association of unfimbriated mutant AAEC072 in artificial seawater and in hemolymph serum, respectively. Such differences were apparently due to different adhesive properties since MG155 adhered more efficiently than AAEC072 when hemocytes were incubated at 4 degrees C to inhibit the internalization process. Hemolymph serum increased both association and adherence of MG155 two- to threefold but did not affect association and adherence of AAEC072. MG155 was also 1.5- to 1.7-fold more sensitive to killing by hemocytes than AAEC072, as evaluated by the number of culturable bacteria after 60 and 120 min of incubation. The role of type 1 fimbriae in MG155 interactions with hemocytes was confirmed by the inhibitory effect of D-mannose. In in vivo experiments MG155 cells were cleared from circulating hemolymph more rapidly than AAEC072 cells were cleared. These results confirm that surface properties are crucial in influencing bacterial persistence and survival within mussel hemolymph.

Animals↗
PubMed1999

Role of surface proteins in Vibrio cholerae attachment to chitin.

The role of surface proteins in Vibrio cholerae attachment to chitin particles in vitro was studied. Treatment of V. cholerae O1 ATCC 14034 and ATCC 14035 with pronase E reduced the attachment of bacteria to chitin particles by 57 to 77%. A statistically significant reduction was also observed when the attachment to chitin was evaluated in the presence of homologous Sarkosyl-insoluble membrane proteins (MPs) (67 to 84%), N-acetylglucosamine (GlcNAc) (62%), the sugar that makes up chitin, and wheat germ agglutinin (40 to 56%), a lectin that binds GlcNAc. The soluble oligomers N,N'-diacetylchitobiose or N,N', N"-triacetylchitotriose caused an inhibition of 14 to 23%. Sarkosyl-insoluble MPs able to bind chitin particles were isolated and visualized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis; two of these peptides (molecular sizes, 36 and 53 kDa) specifically bind GlcNAc.

Acetylglucosamine↗
PubMed1998

Effect of low-molecular-weight chitosans on the adhesive properties of oral streptococci.

It was previously shown that a low-molecular-weight chitosan and its derivatives N-carboxymethyl chitosan and imidazolyl chitosan inhibit Streptococcus mutans adsorption to hydroxyapatite. The ability of the same molecules to interfere with adhesive properties of other oral streptococci (Streptococcus sanguis, Streptococcus gordonii, Streptococcus constellatus, Streptococcus anginosus, Streptococcus intermedius, Streptococcus oralis, Streptococcus salivarius, Streptococcus vestibularis) was tested. When saliva-coated or -uncoated hydroxyapatite beads were treated with N-carboxymethyl chitosan, a reduction varying from 60% to 98% depending on strains was observed. Low-molecular-weight chitosans and imidazolyl chitosan did not have any effect. Growth in N-carboxymethyl chitosan-supplemented medium (final concentrations ranging from 20 to 500 micrograms.ml-1) caused a dose related reduction in the adsorption of all strains to hydroxyapatite and in their affinity towards xylene. No effect was observed with low-molecular-weight chitosans and imidazolyl chitosan. In contrast to what observed with S. mutans, the three polysaccharides did not affect detachment from hydroxyapatite beads and adherence to cheek epithelial cells of the other streptococci. These results suggest that low-molecular-weight chitosans and/or imidazolyl chitosan, selectively affecting S. mutans adsorption to hydroxyapatite, may be very interesting as potential anti-dental caries agents.

Adult↗
PubMed1998

Efficient phagocytosis of Klebsiella pneumoniae strains that poorly bind to human polymorphonuclear leukocytes.

The phagocytosis process of unencapsulated MIAT-negative strains that, although binding very poorly to human polymorphonuclear leukocytes (PMN) at 4 degrees C, are efficiently killed by these cells at 37 degrees C, was studied. At 37 degrees C the number of bacteria bound to the PMN external surface was similar to that observed at 4 degrees C (about 100 bacteria/100 PMN after 60 min); on the contrary the number of internalized bacteria was much higher (from 500 bacteria/100 PMN after 60 min). Interactions between phagocytosis-sensitive Klebsiella pneumoniae strains (PSK) and PMN were then compared with those of two isogenic Escherichia coli strains with and without type 1 fimbriae. Whereas PSK strain binding to blocked PMN was very slow and became significant only after 5-6 h, that of phagocytosis-sensitive fimbriated E. coli was rapid and efficient. Phagocytosis-resistant, non fimbriated E. coli strain bound with an efficiency that, within the first 60 min, was not very different from that of the PSK strains. However, longer incubations led to increases in PSK binding, whereas unfimbriated E. coli remained constant. PSK and fimbriated E. coli strains were efficiently internalized and killed, whereas the unfimbriated E. coli strain was not. It is suggested that PMN can phagocytize unopsonized bacteria through two different mechanisms. By one mechanism, observed with the fimbriated E. coli strain, PMN bind many more bacteria than those they can internalize. By the other, observed with PSK strains, PMN bind only the bacteria they can immediately internalize.

Bacterial Adhesion↗
PubMed1997

News & notes: adhesiveness of Bacteroides fragilis strains isolated from feces of healthy donors, abscesses, and blood.

Bacteroides fragilis strains attached to oral epithelial cells (ECs) and the cell line Intestine 407 and associated with human phagocytes with different efficiencies depending on their source. The 58%, 75%, and 40% of strains isolated from feces, abscesses, and blood respectively adhered to ECs with good efficiency (11-40 bacteria/cell). Of the strains from feces and abscesses, 17% and 20% exhibited a high adherence (>40 bacteria/cell); however, none of the blood isolates presented this property. Similar results were obtained with the cell line Intestine 407 and human phagocytes. Of the isolates from feces, abscesses, and blood, 20%, 56%, and 71% respectively also exhibited hemagglutination ability, indicating that this property is a virulence trait more frequently present among pathogenic isolates than in commensal strains.

Abscess↗
PubMed1997

Inhibition of Streptococcus mutans adsorption to hydroxyapatite by low-molecular-weight chitosans.

The role of Streptococcus mutans in the initiation of dental caries has been recognized and attributed, at least in part, to its ability to colonize the tooth surface. Therefore, factors which prevent S. mutans attachment to hydroxyapatite (HA) are of considerable interest for the prophylaxis of this infectious disease. Chitosan, a chitin derivative by N-deacetylation, is an interesting candidate in this respect, since it stimulates the ordered regeneration of oral soft tissues, prevents the deleterious action of organic acid, and exhibits bactericidal action against several pathogens. In the present work, the efficacy of a low-molecular-weight chitosan (LMWC) and its derivatives N-carboxymethyl chitosan (NCMC) and imidazolyl chitosan (IMIC) in preventing S. mutans attachment to HA beads was assessed. The effects of chitosan on both sucrose-dependent and -independent adherence were evaluated. In both cases, when saliva-coated or uncoated HA beads were treated with any of the chitosans, a reduction in S. mutans adsorption ranging from 47 to 66% was observed. When HA beads were coated with saliva after the treatment with chitosan, neither carbohydrate caused a statistically significant reduction in S. mutans adsorption, suggesting that saliva deposition restores HA binding properties. Bacteria grown in the presence of chitosan subminimal inhibitory concentrations (sub-MICs) ranging from 12 to 500 micrograms mL-1 adsorbed poorly to HA and exhibited a lower affinity toward xylene than untreated controls. In the presence of chitosan sub-MICs up to 60 micrograms mL-1, an increase in the percentage of detached bacteria from two- to nine-fold was observed. The desorptive effect of chitosan was weaker when S. mutans had adhered to saliva-coated HA in the presence of sucrose. These results demonstrate that the presence of minor amounts of modified chitosans prevents S. mutans adsorption to HA and suggest that colonization of the tooth surface might be impaired by the use of toothpastes, mouthrinses, or chewing gums containing any of the tested polysaccharides.

Adsorption↗
PubMed1996

Attachment of Vibrio alginolyticus to chitin mediated by chitin-binding proteins.

Vibrio alginolyticus is the only culturable vibrio associated with the chitinaceous carapace of the copepod Tigriopus fulvus (Fisher 1860) living in Ligurian coastal rock pools (Tyrrhenian Sea). The characteristics of the interaction between chitin particles and V. alginolyticus were studied by analysing strains isolated both from the copepod surface and from rock-pool water. The highest degree of attachment to chitin was observed at 20 degrees C, in the presence of 3% NaCl. Bacterial treatment with N-acetylglucosamine and pronase E caused a reduction in attachment of 52-62% and 77-94%, respectively. Chitin pretreatment with either wheat germ agglutinin or membrane proteins (MPs) from V. alginolyticus caused a reduction in attachment, of 50-57% and 53-70%, respectively. No inhibition was observed when bacteria were pretreated with D-glucose, D-fucose or D-fructose, or when chitin was pretreated with concanavalin A and Escherichia coli DH5 alpha MPs. V. alginolyticus MPs able to bind chitin were isolated and analysed by SDS-PAGE. Four chitin-binding proteins were visualized in all tested strains (53, 35, 20 and 14 kDa); in vivo these peptides may efficiently mediate V. alginolyticus attachment to chitin-containing substrates.

Acetylglucosamine↗
PubMed1995

Export of Bordetella pertussis serotype 2 and 3 fimbrial subunits by Escherichia coli.

Bordetella pertussis serotype 2 and 3 fimbrial subunits were expressed and exported in Escherichia coli using the recently described expression/secretion vector pCGV1. Two protease deficient E. coli strains (CAG629 and EC538) and two periplasmic-leaky mutants (AE84064 and A593) were transformed with the different constructs and, after thermal induction, proteins present in the various cellular compartments were analyzed by Western blot. The results obtained with the two types of fimbrial subunits were generally the same: a recombinant protein of the expected molecular mass (19.2 kDa) was present in the periplasm of the leaky mutants and of CAG629 strain (Ion protease- and heat shock protease-deficient). Only the expression of the recombinant fimbrial subunits by the tolB A593 mutant resulted in protein release into the extracellular medium. These results indicate that the use of hybrid plasmids based on pCGV1 in combination with the tolB mutant constitute an efficient system for the export of recombinant proteins.

Adhesins, Bacterial↗
PubMed1994

A novel Escherichia coli expression-export vector containing alkaline phosphatase as an insertional inactivation screening system.

An Escherichia coli expression-export vector was constructed (pCGV1, 6.3 kb) containing the alkaline phosphatase structural gene (phoA) located downstream from the phage lambda pR and pL promoters positioned in tandem and the cIts857 gene encoding lambda thermosensitive repressor. The phoA gene is fused to DNA encoding a hybrid signal sequence that contains the N-terminal portion of the beta-lactamase (Bla) signal sequence and the C-terminal region of the PhoA signal sequence. Within the DNA encoding hybrid signal sequence, a unique NheI restriction site is present where polymerase chain reaction (PCR)-amplified genes may be cloned. The 5' PCR primers reconstitute the C-terminal portion of either the PhoA or Bla signal sequences to restore an intact signal peptide. Recombinant phoA- clones are selected on indicator plates containing 5-bromo-4-chloro-3-indolyl phosphate.

Alkaline Phosphatase↗
PubMed1993

The use of monoclonal antibodies for studying the biological properties of Staphylococcus aureus endo-beta-N-acetylglucosaminidase.

Staphylococcus aureus endo-beta-N-acetylglucosaminidase (SaG) has been suggested to function as a virulence determinant which interferes with the host cellular immune response. To further characterize the biological properties of SaG, monoclonal antibodies (mAbs) were raised against purified SaG. Four IgG1 subclass mAbs were obtained, none of which reacted with the reduced, sodium dodecyl sulphate pretreated or boiled enzyme. The ability of the mAbs to react with the enzymes present in supernatants obtained from 197 S. aureus strains indicated that they recognized epitopes which are highly conserved; bacteriolytic enzymes produced by staphylococci other than S. aureus did not show any cross-reactivity. After pretreatment of SaG with mAbs (mAb-SaG molar ratios varying from 1 to 20), it was shown that all selected mAbs caused, at a mAb:SaG molar ratio of 10, a 90% inhibition of SaG bacteriolytic activity and a statistically significant reduction of its ability to interfere with phagocytosis by human polymorphonuclear leukocytes. All selected mAbs reacted with several commercially available exo-beta-N-acetylglucosaminidases; mAb C1/10-11 also reacted with chicken and turkey egg muramidases and, at a mAb:SaG molar ratio of 10, inhibited their bacteriolytic activity by 97%. This suggests that one or more epitopes present in the above exo-glucosaminidases and muramidases share some degree of homology with others present in SaG.

Acetylglucosaminidase↗
PubMed1993

Occurrence of Vibrio alginolyticus in Ligurian Coast Rock Pools (Tyrrhenian Sea, Italy) and Its Association with the Copepod Tigriopus fulvus (Fisher 1860).

A study of heterotrophic bacteria and vibrios adhering to the copepod Tigriopus fulvus, which lives in Ligurian coast rock pools (Tyrrhenian Sea), was carried out from November 1990 to October 1991. Heterotrophic bacteria, which were always found both free in the water and bound to the T. fulvus organisms, showed a correlation with water temperature and salinity. Vibrio alginolyticus was found free in the water and bound to T. fulvus surfaces during the warmest months. Temperature is the main factor influencing the presence of V. alginolyticus in the rock pool. Attachment of this microorganism to the copepod provides a mechanism for its extended geographic distribution.

Journal Article↗
PubMed1993

Rapid methods for identification of Staphylococcus aureus when both human and animal staphylococci are tested: comparison with a new immunoenzymatic assay.

A new immunoenzymatic assay (IEA) for the identification of Staphylococcus aureus strains of both human and animal origin was compared with rapid commercial kits. The sensitivities and specificities of the commercial kits varied from 90.2 to 96% and 90.8 to 93.7%, respectively. The IEA did not give any false-negative or false-positive results, while commercial kits gave high percentages of false-positive results among clumping factor-positive non-S. aureus strains. The IEA is particularly useful for isolates for which identification is doubtful, for large-scale epidemiological studies, and for identifying isolates from animals as S. aureus.

Animals↗
PubMed1992

Novel immunoenzymatic assay for identification of coagulase- and protein A-negative Staphylococcus aureus strains.

A purified monoclonal antibody (MAb) which specifically reacts with Staphylococcus aureus glucosaminidase was obtained. This MAb was utilized to develop an immunoenzymatic assay for the identification of S. aureus strains. The sensitivity of this assay, based on the simultaneous detection of S. aureus glucosaminidase and protein A, was evaluated by analyzing a total of 196 strains, 26 of which did not exhibit one or more of the following properties: protein A, clumping factor, and staphylocoagulase. All strains yielded positive results by the MAb-based immunoenzymatic test. The assay's ability to differentiate between S. aureus and other staphylococci was then analyzed by testing a total of 277 non-S. aureus strains that yielded negative results. Our data demonstrate that this immunoenzymatic assay can be used as a single S. aureus identification criterion, particularly useful for those strains negative for clumping factor, staphylocoagulase, or protein A.

Animals↗
PubMed1991

Enterococcus faecalis: specific and non-specific interactions with human polymorphonuclear leukocytes.

In previous studies we have demonstrated that the ability of Enterococcus faecalis to adhere to and to be internalized in human urinary tract epithelial cells, Girardi Heart cells and human polymorphonuclear leukocytes (PMNs), was dependent on whether the strain had been isolated from urinary tract infections (UTI) or endocarditis (EN) respectively. These properties were further modified by growth of the organism in human serum. In the present report, using competition assays we show that adhesins containing a D-glucose moiety play a role in mediating the interactions between human PMNs and E. faecalis strains isolated from UTI and grown in brain-heart infusion broth (BHIB). On the other hand, adhesins containing both D-glucose and D-galactose moieties were involved in the interactions between PMNs and serum grown UTI isolates or EN isolates grown in either BHIB or human serum. Moreover, the impairment in the association between both UTI and EN strains after growth in serum appears to be at least partially related to a decrease in enterococcal surface hydrophobicity.

Adult↗