160 research outputs found
Species diversity, spatial distribution, and virulence associated genes of culturable vibrios in a brackish coastal Mediterranean environment
The Vibrio genus is widespread in marine and brackish environments, and several species are human and animal pathogens of global importance. Vibrios adapt rapidly to many environmental stresses, so that brackish environments can be both a suitable niche and a possible reservoir for them. To test the occurrence of culturable vibrios and their
possible correlation with environmental factors in a temperate brackish environment, a 1year sampling study was performed in three brackish ponds located along the Central Thyrrenian coast in the Macchiatonda Nature Reserve (Santa Marinella, district of Rome, Italy). Molecular methods were used to detect Vibrio cholerae, Vibrio arahaemolyticus,
and Vibrio vulnificus pathogenicity associated genes among the Vibrio isolates. Out of 130 Vibrio isolates identified by sequencing a recA fragment, 70 harbored virulence associated genes including ctx, ace, tcpA, tdh, trh, vvhA, vllY, and toxRS, so confirming the spread of virulence determinants across the environmental isolates. Ecological analysis showed that, although the water temperature is known to be a strong predictor of abundance and distribution of vibrios, its influence accounts for 27 % of the observed variance in the Macchiatonda samples, increasing to 40 % when combined with salinity
The molecular class C acid phosphatase of Chryseobacterium meningosepticum (OlpA) is a broad-spectrum nucleotidase with preferential activity on 5'-nucleotides
The olpA gene of Chryseobacterium meningosepticum, encoding a molecular class C phosphatase, was cloned and expressed in Escherichia coli. The gene encodes a 29-kDa polypeptide containing an amino-terminal signal peptide typical of bacterial membrane lipoproteins. Expression in E. coli results in a functional product that mostly partitions in the outer membrane. A secreted soluble OlpA derivative (sOlpA) lacking the N-terminal cysteine residue for lipid anchoring was produced in E. coli and purified by means of two steps of ion exchange chromatography. Analysis of the kinetic parameters of sOlpA with several organic phosphoesters revealed that the enzyme was able to efficiently hydrolyze nucleotide monophosphates, with a strong preference for 5'-nucleotides and for 3'-AMP. The enzyme was also able to hydrolyze sugar phosphates and beta-glycerol phosphate, although with a lower efficiency, whereas it was apparently inactive against nucleotide di- and triphosphates, diesters, and phytate. OlpA, therefore, can be considered a broad-spectrum nucleotidase with preference for 5'-nucleotides. Its functional behaviour exhibits differences from that of the Haemophilus influenzae OMP P4 lipoprotein, revealing functional heterogeneity among phosphatases of molecular class C
A bacterial ratchet motor
Self-propelling bacteria are a dream of nano-technology. These unicellular
organisms are not just capable of living and reproducing, but they can swim
very efficiently, sense the environment and look for food, all packaged in a
body measuring a few microns. Before such perfect machines could be
artificially assembled, researchers are beginning to explore new ways to
harness bacteria as propelling units for micro-devices. Proposed strategies
require the careful task of aligning and binding bacterial cells on synthetic
surfaces in order to have them work cooperatively. Here we show that asymmetric
micro-gears can spontaneously rotate when immersed in an active bacterial bath.
The propulsion mechanism is provided by the self assembly of motile Escherichia
coli cells along the saw-toothed boundaries of a nano-fabricated rotor. Our
results highlight the technological implications of active matter's ability to
overcome the restrictions imposed by the second law of thermodynamics on
equilibrium passive fluids.Comment: 4 pages, 3 figure
Listeria Monocytogenes in a Young Patient with Non Hodgkin's Lymphoma: Case Report
Listeria monocytogenes is an intracellular food-borne pathogen, widely distributed in the environment, which rarely causes clinical infection in healthy people, but may cause severe disease in immunocompromised patients. A case of listeriosis is certified in an immunocompromised patient, thus confirming this microorganism to be an opportunistic human pathogen
Gut microbiota related to Giardia duodenalis, Entamoeba spp. and Blastocystis hominis infections in humans from CĂŽte d'Ivoire
Introduction: Literature data provide little information about protozoa infections and gut microbiota compositional shifts in humans. This
preliminary study aimed to describe the fecal bacterial community composition of people from CĂŽte dâIvoire harboring Giardia duodenalis,
Entamoeba spp., and Blastocystis hominis, in trying to discover possible alterations in their fecal microbiota structure related to the presence
of such parasites.
Methodology: Twenty fecal samples were collected from people inhabiting three different localities of CĂŽte dâIvoire for copromicroscopic
analysis and molecular identification of G. duodenalis, Entamoeba spp., and B. hominis. Temporal temperature gradient gel electrophoresis
(TTGE) was used to obtain a fingerprint of the overall bacterial community; quantitative polymerase chain reaction (qPCR) was used to define
the relative abundances of selected bacterial species/group, and multivariate statistical analyses were employed to correlate all data.
Results: Cluster analysis revealed a significant separation of TTGE profiles into four clusters (p < 0.0001), with a marked difference for G.
duodenalis-positive samples in relation to the others (p = 5.4Ă10-6
). Interestingly, qPCR data showed how G. duodenalis-positive samples were
related to a dysbiotic condition that favors potentially harmful species (such as Escherichia coli), while Entamoeba spp./B. hominis-positive
subjects were linked to a eubiotic condition, as shown by a significantly higher Faecalibacterium prausnitzii-Escherichia coli ratio.
Conclusions: This preliminary investigation demonstrates a differential fecal microbiota structure in subjects infected with G. duodenalis or
Entamoeba spp./B. hominis, paving the way for using further next-generation DNA technologies to better understand host-parasite-bacteria
interactions, aimed at identifying potential indicators of microbiota changes
Structural variations of vaginal and endometrial microbiota. Hints on female infertility
Microbiota are microorganismal communities colonizing human tissues exposed to the external environment, including the urogenital tract. The bacterial composition of the vaginal microbiota has been established and is partially related to obstetric outcome, while the uterine microbiota, considered to be a sterile environment for years, is now the focus of more extensive studies and debates. The characterization of the microbiota contained in the reproductive tract (RT) of asymptomatic and infertile women, could define a specific RT microbiota associated with implantation failure. In this pilot study, 34 women undergoing personalized hormonal stimulation were recruited and the biological samples of each patient, vaginal fluid, and endometrial biopsy, were collected immediately prior to oocyte-pick up, and sequenced. Women were subsequently divided into groups according to fertilization outcome. Analysis of the 16s rRNA V4-V5 region revealed a significant difference between vaginal and endometrial microbiota. The vaginal microbiota of pregnant women corroborated previous data, exhibiting a lactobacilli-dominant habitat compared to non-pregnant cases, while the endometrial bacterial colonization was characterized by a polymicrobial ecosystem in which lactobacilli were exclusively detected in the group that displayed unsuccessful in vitro fertilization. Overall, these preliminary results revisit our knowledge of the genitourinary microbiota, and highlight a putative relationship between vaginal/endometrial microbiota and reproductive success
A comprehensive evaluation of colonic mucosal isolates of Sutterella wadsworthensis from inflammatory bowel disease
Peer reviewedPublisher PD
Has VZV epidemiology changed in Italy? Results of a seroprevalence study
The aim of the study was to evaluate if and how varicella prevalence has changed in Italy. In particular a seroprevalence study was performed, comparing it to similar surveys conducted in pre-immunization era. During 2013â2014, sera obtained from blood samples taken for diagnostic purposes or routine investigations were collected in collaboration with at least one laboratory/center for each region, following the approval of the Ethics Committee. Data were stratified by sex and age. All samples were processed in a national reference laboratory by an immunoassay with high sensitivity and specificity. Statutory notifications, national hospital discharge database and mortality data related to VZV infection were analyzed as well. A total of 3707 sera were collected and tested. In the studied period both incidence and hospitalization rates decreased and about 5 deaths per year have been registered. The seroprevalence decreased in the first year of life in subjects passively protected by their mother, followed by an increase in the following age classes. The overall antibody prevalence was 84%. The comparison with surveys conducted with the same methodology in 1996â1997 and 2003â2004 showed significant differences in age groups 1â19 y. The study confirms that in Italy VZV infection typically occurs in children. The impact of varicella on Italian population is changing. The comparison between studies performed in different periods shows a significant increase of seropositivity in age class 1â4 years, expression of vaccine interventions already adopted in some regions
- âŠ