Biomedical subjects

Enrico Tortoli

Publications and source records attributed to Enrico Tortoli.

At least 19 recordsLinked to original sources

PubMed2006

Molecular analysis of clinical isolates of Mycobacterium bovis recovered from humans in Italy.

In order to achieve a better knowledge of Mycobacterium bovis epidemiology in Italy, 42 clinical isolates from humans were genotyped. Predominant molecular patterns were found in one cluster of 15 isolates sharing spoligotype (ST482), variable-number tandem repeat (VNTR), and IS6110-based restriction fragment length polymorphism (one 1.9-kb band) profiles and in two clusters of 6 and 3 Mycobacterium bovis BCG isolates differing by one VNTR character. The remaining 18 isolates yielded unique profiles. Our results confirm the potential utility of spoligotyping and VNTR typing as a major typing system of M. bovis isolates.

Chromatography, High Pressure Liquid↗

PubMed2006

Mycobacterium sherrisii isolation from a patient with pulmonary disease.

The characterization of 2 clinical isolates of Mycobacterium sherrisii provides further phenotypic and genotypic information beyond that reported in the article that originally described this species. One of our strains was responsible for pulmonary disease in a middle-aged non-HIV patient; thus, confirming the potential pathogenicity of this species previously reported only in an HIV-positive patient.

Bacterial Proteins↗

PubMed2006

Mycobacterium tuberculosis complex genetic diversity: mining the fourth international spoligotyping database (SpolDB4) for classification, population genetics and epidemiology.

BACKGROUND: The Direct Repeat locus of the Mycobacterium tuberculosis complex (MTC) is a member of the CRISPR (Clustered regularly interspaced short palindromic repeats) sequences family. Spoligotyping is the widely used PCR-based reverse-hybridization blotting technique that assays the genetic diversity of this locus and is useful both for clinical laboratory, molecular epidemiology, evolutionary and population genetics. It is easy, robust, cheap, and produces highly diverse portable numerical results, as the result of the combination of (1) Unique Events Polymorphism (UEP) (2) Insertion-Sequence-mediated genetic recombination. Genetic convergence, although rare, was also previously demonstrated. Three previous international spoligotype databases had partly revealed the global and local geographical structures of MTC bacilli populations, however, there was a need for the release of a new, more representative and extended, international spoligotyping database. RESULTS: The fourth international spoligotyping database, SpolDB4, describes 1939 shared-types (STs) representative of a total of 39,295 strains from 122 countries, which are tentatively classified into 62 clades/lineages using a mixed expert-based and bioinformatical approach. The SpolDB4 update adds 26 new potentially phylogeographically-specific MTC genotype families. It provides a clearer picture of the current MTC genomes diversity as well as on the relationships between the genetic attributes investigated (spoligotypes) and the infra-species classification and evolutionary history of the species. Indeed, an independent Naïve-Bayes mixture-model analysis has validated main of the previous supervised SpolDB3 classification results, confirming the usefulness of both supervised and unsupervised models as an approach to understand MTC population structure. Updated results on the epidemiological status of spoligotypes, as well as genetic prevalence maps on six main lineages are also shown. Our results suggests the existence of fine geographical genetic clines within MTC populations, that could mirror the passed and present Homo sapiens sapiens demographical and mycobacterial co-evolutionary history whose structure could be further reconstructed and modelled, thereby providing a large-scale conceptual framework of the global TB Epidemiologic Network. CONCLUSION: Our results broaden the knowledge of the global phylogeography of the MTC complex. SpolDB4 should be a very useful tool to better define the identity of a given MTC clinical isolate, and to better analyze the links between its current spreading and previous evolutionary history. The building and mining of extended MTC polymorphic genetic databases is in progress.

Computational Biology↗

PubMed2006

Mycobacterium colombiense sp. nov., a novel member of the Mycobacterium avium complex and description of MAC-X as a new ITS genetic variant.

Forty-five mycobacterial strains isolated from 23 Colombian HIV-positive patients were identified as members of the Mycobacterium avium complex (MAC) and were characterized using different molecular approaches. Seven of the isolates showed characteristic features that allowed them to be differentiated from other members of the complex. The isolates had a novel 16S-23S rRNA internal transcribed spacer (ITS 1) gene sequence which is described as a new sequevar, MAC-X. All of the seven novel isolates gave a positive result with the MAC-specific AccuProbe (Gen-Probe), but tested negative for Mycobacterium avium and Mycobacterium intracellulare species-specific probes (64 and 100 % of the isolates, respectively). The novel isolates could be differentiated phenotypically from other members of the MAC on the basis of the production of urease and by a consistent mycolic acid pattern. The novel isolates shared some characteristics with M. avium, such as the avium variant I (av-I) pattern of the hsp65 gene as determined by PCR restriction analysis and a positive PCR result for the mig (macrophage-induced) gene. However, the novel isolates showed a unique 16S rRNA gene sequence. DNA-DNA relatedness values, from 24 to 44 %, confirmed the distinction of the novel isolates from other members of the MAC at the genetic level and their status as members of a separate species. The novel isolates are proposed as representatives of a novel species, Mycobacterium colombiense sp. nov., that is closely related to M. avium within the MAC. The type strain is 10B(T) (=CIP 108962(T)=CECT 3035(T)).

Bacterial Typing Techniques↗

PubMed2006

Mycobacterium monacense sp. nov.

Four bacterial strains were isolated from independent clinical specimens in different countries and their genotypic and phenotypic characters support their classification in a novel species within the genus Mycobacterium. One strain was clearly responsible for a severe, post-traumatic wound infection in a healthy boy. The novel species, for which the name Mycobacterium monacense sp. nov. is proposed, is yellow-pigmented, non-photochromogenic and grows in less than a week on solid medium. Based on phenotypic investigations alone, distinction of these four strains from known scotochromogenic rapidly growing strains is problematic. However, the novel strains differ from any other mycobacterium in each of the molecular species markers investigated: the 16S rRNA gene, the 16S-23S rRNA gene internal transcribed spacer and the hsp65 gene. Of the strains investigated, two different sequevars were detected for the hsp65 region. Phylogenetic analysis revealed that these four strains were most closely related to Mycobacterium doricum. The type strain of Mycobacterium monacense sp. nov. is B9-21-178T (=DSM 44395T=CIP 109237T).

Adult↗

PubMed2006

Successfully treated spondylodiscitis due to a previously unreported mycobacterium.

A non-tuberculous mycobacterium was isolated, following a vertebral needle aspiration, from the blood of a patient with severe spondylodiscitis. The strain turned out to be different from any known mycobacterial species and was quite drug-susceptible in vitro. The patient improved markedly following treatment with meropenem, clarithromycin and amikacin.

Antitubercular Agents↗

PubMed2006

Mutations in mutT genes of Mycobacterium tuberculosis isolates of Beijing genotype.

Missense alterations in genes mutT4 and mutT2, which encode DNA repair enzymes, were sequenced from 30 clinical isolates of Mycobacterium tuberculosis of Beijing genotype, mostly from patients with primary tuberculosis, to evaluate their contribution to anti-mycobacterial drug resistance. The mutation Arg to Gly at codon position 48 (CGG to GGG) of mutT4 was found in 21 isolates; of these, 16 isolates also harboured the mutation Gly to Arg at position 58 (GGA to CGA) of mutT2. No statistically significant association was found between mutT4 and mutT2 mutations, and drug resistance. Furthermore, no mutations in mutT4 or mutT2 were found in any of 24 isolates resistant to multiple drugs, nor in 28 anti-mycobacterial drug-susceptible isolates of different genotypes. These data confirm that the polymorphism of mutT genes is characteristic and unique to the Beijing phylogenetic lineage. The mutator phenotype does not appear to increase prevalence of drug resistance, but further studies are required to investigate the mutation rates of Beijing isolates in response to drug exposure.

Amino Acid Substitution↗

PubMed2006

The new mycobacteria: an update.

The continuous evolution of mycobacterial taxonomy may represent a source of confusion for laboratories and clinicians. Apart from the obvious pathogenic strains of the Mycobacterium tuberculosis complex, Mycobacterium leprae and Mycobacterium ulcerans, the role of other mycobacteria may be associated with varying conditions ranging from contamination to specific disease processes. Of the more than 120 mycobacterial species recognized currently, very few have not been reported as pathogenic in humans or animals. Although the attempt to keep pace with the steadily increasing number of mycobacterial species seems hopeless, a careful review of the recent literature relevant to the newly described species may be advantageous. The aim of this present update is to provide epidemiological and clinical information along with major phenotypic and genotypic characteristics of the species described in the last 3 years.

Animals↗

PubMed2006

Evaluation of the new GenoType Mycobacterium assay for identification of mycobacterial species.

The new commercial assay GenoType Mycobacterium, intended for the identification of mycobacteria, was evaluated with a panel of 197 strains belonging to 86 different taxa. The system, which relies on solid-phase reverse hybridization, is composed of two different kits: GenoType CM for the identification of more frequently detected mycobacterial species and GenoType AS for less common species. The sensitivity and specificity were 97.9% and 92.4% for the CM kit and 99.3% and 99.4% for the AS kit. Our results show that the system may represent a useful tool to substantially enlarge the number of mycobacteria that can be reliably identified in clinical laboratories.

Bacterial Typing Techniques↗

PubMed2006

[Characterization of two new pigmented mycobacteria isolates].

Two pigmented mycobacteria isolated from sputum specimens were described by biochemical tests, whole-cell fatty acid analyses by High Performance Liquid Chromatography (HPLC) and sequencing of 65-kDa heat shock protein gene and 16S rRNA gene. The hsp65 gene and 16S rRNA gene sequences of the Mycobacterium sp. G1368 and Mycobacterium sp. E498 were deposited in DDBJ/EMBL/GenBank under accession numbers AY553874, DQ324791 and AY379074, DQ324792, respectively. Mycobacterium sp. G1368 grew in about one week at 37 degrees C and 42 degrees C and produced smooth, yellow colonies. It reduced tellurite and hydrolyzed urea. Nitrate reduction, aryl sulfatase, pyrazin amidase, heat stable catalase and semiquantitative catalase tests were also positive, while Tween 80 hydrolysis was weakly positive. Mycobacterium sp. E498 grew in about 9 days at 37 degrees C and formed smooth, yellow colonies. It hydrolyzed Tween 80, possessed aryl sulfatase, pyrazin amidase and heat stable catalase, however, it did not possess urease and nitrate reductase. These data, in addition to their position in the phylogenetic tree, strongly support the status of novel species at least for Mycobacterium sp. G1368.

Bacterial Proteins↗

PubMed2005

Mycobacterium lentiflavum, an emerging pathogen?

Three cases of infection due to Mycobacterium lentiflavum, a recently described species characterized by multiple resistance to anti-mycobacterial drugs, are reported here. While one case simply adds to the number of cervical lynphadenitis reported in literature, the others concern the first isolations from pleural effusions, in a young boy with leukaemia and in an elderly patient with lung disease, respectively.

Adolescent↗

PubMed2005

Mycobacterium florentinum sp. nov., isolated from humans.

Eight mycobacterial strains isolated during an 11 year period from the sputum of independent patients with various pulmonary disorders and, in one case, from a lymph node of a young girl, were found to present identical features. Phenotypic and genotypic characteristics revealed that the most closely related species to these test isolates were Mycobacterium triplex and Mycobacterium lentiflavum. However, the lipids of the cell wall of the test isolates differed from those of the latter species by TLC and presented unique profiles by both GC and HPLC. Genotypic analysis showed that they had unique 16S rRNA gene and internal transcribed spacer (ITS) sequences, and could be differentiated from all other mycobacterial strains by PCR restriction analysis of hsp65. The strains presented high resistance to antimycobacterial drugs. The name Mycobacterium florentinum sp. nov. is proposed for this taxon, with strain FI-93171(T) (=DSM 44852(T) = CIP 108409(T)) as the type strain.

Adult↗

PubMed2005

Genetic diversity, determined on the basis of katG463 and gyrA95 polymorphisms, Spoligotyping, and IS6110 typing, of Mycobacterium tuberculosis complex isolates from Italy.

Mycobacterium tuberculosis complex isolates (n = 248) collected during a 1-year period in Tuscany, Italy, were genotyped for the katG463 and gyrA95 polymorphisms and by standard spacer oligonucleotide typing (spoligotyping) and IS6110 restriction fragment length polymorphism (RFLP) assays. Most of the isolates (n = 212; 85.5%) belonged to genotypic groups 2 and 3, which included most isolates from Italian-born patients. The remaining isolates were genotypic group 1 organisms, which were prevalent among foreign-born patients (29 of 36; 80.6%). Spoligotype analysis detected 116 unique patterns and 34 clusters including 166 isolates. The combination of spoligotyping and IS6110 RFLP analyses yielded 28 distinct clusters including 65 identical isolates (26.2%)--22 clusters with 2 isolates, 4 clusters with 3 isolates, 1 cluster with 4 isolates, and 1 cluster with 5 isolates--thus proving a low transmission rate in the community. Predominant spoligotypes representing 50% of clustered isolates were found in six clusters that included widespread type ST53 (clade T1) with 29 isolates (11.7% of total isolates); types ST50 and ST47 (Haarlem family) with 18 isolates (7.3%) and 8 isolates (3.2%), respectively; type ST42 (Latino-American and Mediterranean clade) with 13 isolates (5.2%); new type ST1737 (named "Tuscany") with 8 isolates (3.2%); and type ST1 (W-Beijing family) with 7 isolates (2.8%). Other spoligotype families, such as the Mycobacterium africanum, East African-Indian (EAI2/Manila), and central Asia 1 (CAS1/Delhi) families (all including organisms of genotypic group 1) and the Cameroun family (genotypic group 2), were detected especially among immigrant patients. The occurrence of genotypes originally found in distant geographic areas with a high prevalence of tuberculosis may represent a hallmark for changes in the dynamics of transmission of tuberculosis in the region in the near future.

Adult↗

PubMed2005

Infections due to the newly described species Mycobacterium parascrofulaceum.

We report on four cases of infection by the recently described species Mycobacterium parascrofulaceum. In two cases the mycobacterium was isolated from AIDS patients, while in the others it was responsible for pulmonary disease in elderly men. Our findings suggest that M. parascrofulaceum is an opportunistic pathogen, like many other nontuberculous mycobacterial species.

AIDS-Related Opportunistic Infections↗

PubMed2005

Mycobacterium lentiflavum infection in immunocompetent patient.

Mycobacterium lentiflavum is a recently described nontuberculous mycobacterium that has mainly clinical importance in young children with cervical lymphadenitis and in immunocompromised patients. We describe a case of chronic pulmonary infection in an immunocompetent patient. Our observation confirms clinical, diagnostic, and treatment difficulties in the management of M. lentiflavum infection.

Aged↗

PubMed2004

Taxonomic and phylogenetic status of non-tuberculous mycobacteria in a Caribbean setting.

This report describes detailed taxonomic and phylogenetic analysis of 15 non-tuberculous mycobacteria (NTMs) isolated from human pathological specimens in a Caribbean setting (12 slow-growers and three rapid-growers) that were not identified by cultural and biochemical tests and drug-susceptibility results. These isolates were further studied using PCR restriction fragment length polymorphism analysis (PRA) of a 441bp hsp65 fragment, as well as the sequencing of 16S rDNA and hsp65 DNA, and HPLC of the mycolic acids. Our results showed that taxonomic position of well-defined NTMs was resolved by PRA and sequencing of hsp65, nonetheless, it was not suitable to investigate rarely observed or new strains that required 16S rDNA sequencing and HPLC for a definite response. Unrooted neighbor-joining phylogenetic trees were drawn based upon the 16S rDNA and hsp65 sequences of the 15 NTMs compared with those from described species (73 for 16S rDNA and 45 for hsp65). For most of the NTMs not showing an exactly matching sequence with either hsp65 or 16S rDNA in the GenBank, the phylogenetic tree was able to provide with useful indications about their relatedness to known species. In such a case, a concording HPLC pattern with the sequence data and the place of the strain within the tree could lead to a potential identification. We also identified three identical isolates that define a new mycobacterial species within the group of M. simiae-related mycobacteria. The isolation and characterization of mycobacteria from new settings may lead to identify potential pathogens that may propogate in future because of increased human migration, travels, and climatic and ecological changes of the modern world.

Adolescent↗

PubMed2004

Mycobacterium parmense sp. nov.

The isolation and identification of a novel, slow-growing, scotochromogenic, mycobacterial species is reported. A strain, designated MUP 1182T, was isolated from a cervical lymph node of a 3-year-old child. MUP 1182T is alcohol- and acid-fast, with a lipid pattern that is consistent with those of species that belong to the genus Mycobacterium. It grows slowly at 25-37 degrees C, but does not grow at 42 degrees C. The isolate was revealed to be biochemically distinct from previously described mycobacterial species: it has urease and Tween hydrolysis activities and lacks nitrate reductase, 3-day arylsulfatase and beta-glucosidase activities. Comparative 16S rDNA sequencing showed that isolate MUP 1182T represents a novel, slow-growing species that is related closely to Mycobacterium lentiflavum and Mycobacterium simiae. On the basis of these findings, the name Mycobacterium parmense sp. nov. is proposed, with MUP 1182T (=CIP 107385T=DSM 44553T) as the type strain.

Arylsulfatases↗

PubMed2004

Proposal to elevate the genetic variant MAC-A, included in the Mycobacterium avium complex, to species rank as Mycobacterium chimaera sp. nov.

The possibility that the strains included within the Mycobacterium avium complex (MAC), but not belonging either to M. avium or to Mycobacterium intracellulare, may be members of undescribed taxa, has already been questioned by several taxonomists. A very homogeneous cluster of 12 strains characterized by identical nucleotide sequences both in the 16S rDNA and in the 16S-23S internal transcribed spacer was investigated. Similar strains, previously reported in the literature, had been assigned either to the species M. intracellulare on the basis of the 16S rDNA similarity or to the group of MAC intermediates. However, several phenotypical and epidemiological characteristics seem to distinguish these strains from all other MAC organisms. The unique mycolic acid pattern obtained by HPLC is striking as it is characterized by two clusters of peaks, instead of the three presented by all other MAC organisms. All of the strains have been isolated from humans and all but one came from the respiratory tract of elderly people. The clinical significance of these strains, ascertained for seven patients, seems to suggest an unusually high virulence. The characteristics of all the strains reported in the literature, genotypically identical to the ones described here, seem to confirm our data, without reports of isolations from animals or the environment or, among humans, from AIDS patients. Therefore, an elevation of the MAC variant was proposed and characterized here, with the name Mycobacterium chimaera sp. nov.; this increases the number of species included in the M. avium complex. The type strain is FI-01069T (=CIP 107892T=DSM 44623T).

Aged↗