Valeria Lentini

Pathogenic Vibrio, Aeromonas and Arcobacter spp. associated with copepods in the Straits of Messina (Italy).

In aquatic environments bacteria have a strong affinity for a variety of substrates including animal surfaces. The chitinous skeletons of crustaceans are nutrient sources that encourage bacterial attachment and colonization in marine environment (Sieburth, 1975). Bacteria associated with plankton can survive in adverse environmental conditions longer than free-living forms (Carman and Dobbs, 1997). Zooplankton carry a natural commensal microflora attached to external surfaces and in the digestive tract, mainly composed of Vibrio spp. (Huq et al., 1983; Tamplin et al., 1990). The interest in the occurrence and distribution of vibrios as free living and zooplankton associated involves ecological and epidemiological aspects. The genus Vibrio currently includes 72 species, among these species Vibrio cholerae, Vibrio parahaemolyticus and Vibrio vulnificus account for the majority of Vibrio infections in humans (Farmer et al., 2003). The association of potentially pathogenic vibrios with marine zooplankton has been demonstrated in the Mediterranean Sea for Vibrio alginolyticus, V. cholerae nonO1, V. fluvialis, V. parahaemolyticus and V. vulnificus in different temperature and salinity conditions (Carli et al., 1993; Pruzzo et al., 1996; Montanari et al., 1999; Maugeri et al., 2000a, 2004, 2006; Gugliandolo et al., 2005). While the colonization of copepods, which represent the main component of zooplankton, by vibrios, is a well described phenomenon, little is known for other potentially pathogenic bacteria for humans and animals. Aeromonas spp. are ubiquitous inhabitants of aquatic ecosystems such as freshwater, coastal water and sewage (Monfort and Baleux, 1990; Krovacek et al., 1994). Members of the Aeromonas genus are recognized as pathogens for humans (Janda and Abbott, 1998) and animals including amphibians, reptiles, and fish (Austin and Austin, 1997). Strains of Aeromonas hydrophila, Aeromonas sobria, Aeromonas caviae, Aeromonas veronii and Aeromonas salmonicida have been isolated from coastal waters in Italy (Fiorentini et al., 1998; Sechi et al., 2002). Few reports have dealt with aeromonads associated with marine zooplankton (Alfredsson et al., 1995; Montanari et al., 1999; Dumontet et al., 2000). Arcobacter butzleri, Arcobacter cryaerophilus and Arcobacter skirrowii, included in the family of Campylobacteraceae, have been associated with human and animal enteric diseases (Vandamme et al., 1992) and they are con-

Induction and Resuscitation of Viable Nonculturable Arcobacter butzleri Cells

ABSTRACT Two strains of Arcobacter butzleri, ATCC 49616 and an environmental isolate, became nonculturable in seawater microcosms at 4°C by 20 days and at room temperature by 14 days. Nonculturable cells were viable for up to 270 days of incubation in microcosms. Resuscitation of A. butzleri cells from microcosms at both temperatures was achieved 9 days after nutrient addition.

Specific detection of Arcobacter spp. in estuarine waters of Southern Italy by PCR and fluorescent in situ hybridization.

Aim:  To evaluate the reliability of culture‐independent methods in comparison with culture‐dependent ones for the detection of Arcobacter spp. in estuarine waters of Southern Italy.

Shallow hydrothermal vents in the southern Tyrrhenian Sea

Shallow hydrothermal systems represent particularly suitable fields for studying the interactions between fluids and microorganisms inhabiting extreme environments. Coastal zones of the southern Tyrrhenian Sea are home to shallow hydrothermal systems, related to both active and extinct volcanism, located in the Flegrean area, at Cape Palinuro and around the Eolian Islands. A great diversity of Archaea and Bacteria has been reported at shallow hydrothermal vents, where they are key elements in ecosystem functioning. When compared with deep-sea locations, photosynthetic microorganisms appear to be the main characteristic of shallow hydrothermal vents, where both light and hydrothermal energy support a complex microbial community displaying primary productivity (phototrophic and chemotrophic) of mixed origin. Viriobenthos abundances are low compared with other shallow marine systems, suggesting that viruses are less tolerant than prokaryotes of high temperatures and consequently are believed to have a low impact on prokaryotic abundance and biodiversity. Microorganisms from shallow hydrothermal vents represent an almost unexploited resource for thermostable enzymes and biomolecules potentially valuable in biotechnology.

New bacilli from shallow hydrothermal vents of Panarea Island (Italy) and their biotechnological potential

Aims:  To characterize bacilli isolated from shallow hydrothermal vents of Panarea Island (Italy) and evaluate their biotechnological potential.

Microbial Diversity at a Hot, Shallow-Sea Hydrothermal Vent in the Southern Tyrrhenian Sea (Italy)

Microbial community thriving at shallow hydrothermal vent named Black Point, close to the Island of Panarea in the Southern Tyrrhenian Sea (Italy), was studied by microscopic, cultural and molecular methods. New strains of Bacillus and Geobacillus were isolated. Members of sulphur-oxidizing bacteria, belonging to the genera Halothiobacillus and Thiomicrospira were demonstrated by both culture-dependent and -independent methods. Genetic diversity of Bacteria was higher than that of Archaea. Bacterial 16S rRNA gene sequences from Black Point showed low levels of similarity with other yet deposited sequences, suggesting that new bacterial phylotypes are present in this site. Dominant populations of Bacteria belonged to uncultured members of Proteobacteria (mainly of the class Gammaproteobacteria), Firmicutes and Acidobacteriaceae. Primary production appeared to be supported by chemosynthetic and photosynthetic bacteria affiliated with members of Gammaproteobacteria. Most of the archaeal sequences matched those of yet-uncultivated Archaea, thus their role at this vent is not well understood.

CONVENTIONAL AND MOLECULAR METHODS TO DETECT BACTERIAL PATHOGENS IN MUSSELS

Aim:  To detect Aeromonas spp., Salmonella spp., Vibrio cholerae, Vibrio parahaemolyticus and Vibrio vulnificus in mussels and water samples from a farming area, conventional and molecular methods were applied to enrichment cultures.

Antiviral and immunomodulatory effects of a novel bacterial exopolysaccharide of shallow marine vent origin

To evaluate a novel exopolysaccharide (EPS1) from the recently described haloalkaliphilic, thermophilic Bacillus licheniformis strain T14, isolated from a shallow hydrothermal vent of Panarea Island (Italy), for its antiviral and immunomodulatory effects against herpes simplex virus type 2 (HSV‐2).

Molecular detection of Bartonella henselae and Bartonella clarridgeiae in clinical samples of pet cats from Southern Italy

Bartonella henselae is considered an emerging pathogen of veterinary and medical interest that can be occasionally transmitted to humans. Cats are considered to be the only reservoir host for B. henselae. In this study, we used a nested-PCR assay to investigate the prevalence of B.henselae and Bartonella clarridgeiae DNA in peripheral blood samples, fine needle lymph node aspirate specimens and oral swabs from 85 cats in order to develop an easy diagnostic strategy for the selection of infection-free cats that are being considered as pets, especially for immunocompromised patients. Overall, molecular analysis showed that 71 cats (83.5%) tested PCR positive for the presence of B. henselae DNA. PCR amplification of DNA B. henselae produced positive products from lymph node aspirate specimens (62/85; 72.9%) similar to those obtained from blood samples (60/85; 70.6%) and higher than those from oral swabs (51/85; 60%) of cats. No PCR product was obtained for B. clarridgeiae. The simultaneous analysis of three different clinical samples in our study increased the diagnostic possibilities for B. henselae infection in the examined cats from 60-72.9% to 83.5%. Lymph node aspirates were found to be the most effective clinical samples for the detection of B. henselae and blood samples were the next best. Oral swab samples were used in this study with good results when considered in combination with blood and/or lymph node aspiration. The use of nested-PCR assay on these three clinical samples may enhance the diagnostic sensitivity for bartonellosis in cats irrespective of the clinical status of animals.

Identification of enzyme-producing thermophilic bacilli isolated from marine vents of Aeolian Islands (Italy)

Enzyme-producing thermophilic bacilli were isolated from different thermal sites located in and around Aeolian Islands (Italy) and characterised by both molecular and culture-based methods. Spore-forming bacteria with optimal growth from 45 to 70 °C were isolated from submarine vents and a geothermal well of Aeolian Islands (Italy). Eighteen selected strains were screened for extracellular enzyme presence by using nine substrates: Tween 20, Tween 80, tributyrin, soluble starch, xylan, dextran, carragenan, gelatine and casein. Sixteen isolates were able to grow at pH 9. The isolates were differentiated on the basis of restriction pattern of their amplified 16S rDNA (ARDRA) prior to 16S rRNA gene sequence analysis. On the basis of the most complete sequencing results strain V3 was identified asGeobacillus thermodenitrificans, most of isolates (10/14) was similar at high level (≥95%) to different reference strains of the speciesBacillus licheniformis. The remaining isolates, exhibiting sequence similarity below 95%, may represent novel species of the genusBacillus.