Search PubMed⌕ Search

Biomedical subjects

V Vincent

Publications and source records attributed to V Vincent.

At least 37 records · Page 2Linked to original sources
PubMed2001

Genomic sequence and transcriptional analysis of a 23-kilobase mycobacterial linear plasmid: evidence for horizontal transfer and identification of plasmid maintenance systems.

Linear plasmids were unknown in mycobacteria until recently. Here, we report the complete nucleotide sequence of 23-kb linear plasmid pCLP from Mycobacterium celatum, an opportunistic pathogen. The sequence of pCLP revealed at least 19 putative open reading frames (ORFs). Expression of pCLP genes in exponential-phase cultures was determined by reverse transcriptase PCR (RT-PCR). Twelve ORFs were expressed, whereas no transcription of the 7 other ORFs of pCLP was detected. Five of the 12 transcribed ORFs detected by RT-PCR are of unknown function. Sequence analysis revealed similar loci in both M. celatum pCLP and the Mycobacterium tuberculosis chromosome, including transposase-related sequences. This result suggests horizontal transfer between these two organisms. pCLP also contains ORFs that are similar to genes of bacterial circular plasmids involved in partition (par operon) and postsegregational (pem operon) mechanisms. Functional analysis of these ORFs suggests that they probably carry out similar maintenance roles in pCLP.

Amino Acid Sequence↗
PubMed2001

Characterization of Mycobacterium bohemicum isolated from human, veterinary, and environmental sources.

Chemotaxonomic and genetic properties were determined for 14 mycobacterial isolates identified as members of a newly described species Mycobacterium bohemicum. The isolates recovered from clinical, veterinary, and environmental sources were compared for lipid composition, biochemical test results, and sequencing of the 16S ribosomal DNA (rDNA) and the 16S-23S rDNA internal transcribed spacer (ITS) regions. The isolates had a lipid composition that was different from those of other known species. Though the isolates formed a distinct entity, some variations were detected in the features analyzed. Combined results of the phenotypic and genotypic analyses were used to group the isolates into three clusters. The major cluster (cluster A), very homogenous in all respects, comprised the M. bohemicum type strain, nine clinical and veterinary isolates, and two of the five environmental isolates. Three other environmental isolates displayed an insertion of 14 nucleotides in the ITS region; they also differed from cluster A in fatty alcohol composition and produced a positive result in the Tween 80 hydrolysis test. Among these three, two isolates were identical (cluster B), but one isolate (cluster C) had a unique high-performance liquid chromatography profile, and its gas liquid chromatography profile lacked 2-octadecanol, which was present in all other isolates analyzed. Thus, sequence variation in the 16S-23S ITS region was associated with interesting variations in lipid composition. Two of the isolates analyzed were regarded as potential inducers of human or veterinary infections. Each of the environmental isolates, all of which were unrelated to the cases presented, was cultured from the water of a different stream. Hence, natural waters are potential reservoirs of M. bohemicum.

Aged↗
PubMed2001

Genetic diversity of Mycobacterium africanum clinical isolates based on IS6110-restriction fragment length polymorphism analysis, spoligotyping, and variable number of tandem DNA repeats.

A collection of 105 clinical isolates originally identified as Mycobacterium africanum were characterized using both phenotypic and genotyping methods. The phenotypic methods included routine determination of cultural properties and biochemical tests used to discriminate among the members of the M. tuberculosis complex, whereas genotypic characterization was based on IS6110-restriction fragment length polymorphism (IS6110-RFLP) analysis, IS1081-RFLP analysis, direct repeat-based spacer oligonucleotide typing (spoligotyping), variable number of tandem DNA repeats (VNTR), and the polymorphism of the oxyR, pncA, and mtp40 loci. The results obtained showed that a majority of M. africanum isolates were characterized by a specific spoligotyping pattern that was intermediate between those of M. tuberculosis and M. bovis, which do not hybridize with spacers 33 to 36 and spacers 39 to 43, respectively. A tentative M. africanum-specific spoligotyping signature appeared to be absence of spacers 8, 9, and 39. Based on spoligotyping, as well as the polymorphism of oxyR and pncA, a total of 24 isolates were excluded from the final study (19 were identified as M. tuberculosis, 2 were identified as M. canetti, and 3 were identified as M. bovis). The remaining 81 M. africanum isolates were efficiently subtyped in three distinct subtypes (A1 to A3) by IS6110-RFLP analysis and spoligotyping. The A1 and A2 subgroups were relatively more homogeneous upon spoligotyping than A3. Further analysis of the three subtypes by VNTR corroborated the highly homogeneous nature of the A2 subtype but showed significant variations for subtypes A1 and A3. A phylogenetic tree based on a selection of isolates representing the three subtypes using VNTR and spoligotyping alone or in combination confirmed the subtypes described as well as the heterogeneity of subtype A3.

Alleles↗
PubMed2001

Evaluation of PCR-restriction profile analysis and IS2404 restriction fragment length polymorphism and amplified fragment length polymorphism fingerprinting for identification and typing of Mycobacterium ulcerans and M. marinum.

Mycobacterium ulcerans and M. marinum are emerging necrotizing mycobacterial pathogens that reside in common reservoirs of infection and exhibit striking pathophysiological similarities. Furthermore, the interspecific taxonomic relationship between the two species is not clear as a result of the very high phylogenetic relatedness (i.e., >99.8% 16S rRNA sequence similarity), in contrast to only 25 to 47% DNA relatedness. To help understand the genotypic affiliation between these two closely related species, we performed a comparative analysis including PCR restriction profile analysis (PRPA), IS2404 restriction fragment length polymorphism (RFLP), and amplified fragment length polymorphism (AFLP) on a set of M. ulcerans (n = 29) and M. marinum (n = 28) strains recovered from different geographic origins. PRPA was based on a triple restriction of the 3' end region of 16S rRNA, which differentiated M. ulcerans into three types; however, the technique could not distinguish M. marinum from M. ulcerans isolates originating from South America and Southeast Asia. RFLP based on IS2404 produced six M. ulcerans types related to six geographic regions and did not produce any band with M. marinum, confirming the previous findings of Chemlal et al. (K. Chemlal, K. DeRidder, P. A. Fonteyne, W. M. Meyers, J. Swings, and F. Portaels, Am. J. Trop. Med. Hyg. 64:270-273, 2001). AFLP analysis resulted in profiles which grouped M. ulcerans and M. marinum into two separate clusters. The numerical analysis also revealed subgroups among the M. marinum and M. ulcerans isolates. In conclusion, PRPA appears to provide a rapid method for differentiating the African M. ulcerans type from other geographical types but is unsuitable for interspecific differentiation of M. marinum and M. ulcerans. In comparison, whole- genome techniques such as IS 2404-RFLP and AFLP appear to be far more useful in discriminating between M. marinum and M. ulcerans, and may thus be promising molecular tools for the differential diagnosis of infections caused by these two species.

Animals↗
PubMed2001

History of Lap-Band: from dream to reality.

BACKGROUND: Laparoscopy in severely obese patients is a surgical challenge due to the deep operative field, massive visceral fat, hypertrophic and steatotic liver and inadequate instrumentation. However, performing bariatric surgery by laparoscopy permits a minimally invasive procedure in patients who are usually considered high risk because of their morbid obesity. The challenge was to overcome technical difficulties of laparoscopy in the morbidly obese. METHOD: We needed to develop a new surgical protocol for the gastric approach in severely obese patients. The existing silicone band could not be used for laparoscopy, and a new prototype of the silicone band for laparoscopic use was designed. Because of ethical reasons, we began this work on the animal model. In an animal lab program using pigs, we refined the surgical technique of the laparoscopic approach. A new design of the adjustable silicone band for laparoscopic use was developed. RESULTS: After a 1-year animal lab program and approval by the ethics committee, we performed our first human laparoscopic adjustable gastric banding on September 1st, 1993. CONCLUSION: The development of the Lap-Band from concept to animal lab, ending in clinical application, has been an advance in bariatric surgery.

Animals↗
PubMed2001

Mycobacterial infections in domestic and wild animals due to Mycobacterium marinum, M. fortuitum, M. chelonae, M. porcinum, M. farcinogenes, M. smegmatis, M. scrofulaceum, M. xenopi, M. kansasii, M. simiae and M. genavense.

The epidemiology and the natural distribution of Mycobacterium marinum, M. fortuitum, M. chelonae, M. porcinum, M. farcinogenes, M. smegmatis, M. scrofulaceum, M. xenopi, M. kansasii, M. simiae and M. genavense are described. In addition to the bacteriological, biochemical and genetic characteristics, the authors review the pathology of these species, including the natural and experimental diseases and the accompanying lesions, diagnosis, antibiotic sensitivities and treatment of animal infections caused by these mycobacteria.

Animals↗
PubMed2001

Spacer oligonucleotide typing of bacteria of the Mycobacterium tuberculosis complex: recommendations for standardised nomenclature.

Spacer oligonucleotide typing (spoligotyping) is widely used for differentiation of bacteria of the Mycobacterium tuberculosis complex. However, the absence of any standardised method for concise description of spoligotypes makes it difficult to compare the results from different laboratories. This paper describes unambiguous, interconvertible systems for the designation of spoligotype patterns, the adoption of which will be beneficial to mycobacterial research.

Databases, Factual↗
PubMed2000

Variable human minisatellite-like regions in the Mycobacterium tuberculosis genome.

Mycobacterial interspersed repetitive units (MIRUs) are 40-100 bp DNA elements often found as tandem repeats and dispersed in intergenic regions of the Mycobacterium tuberculosis complex genomes. The M. tuberculosis H37Rv chromosome contains 41 MIRU loci. After polymerase chain reaction (PCR) and sequence analyses of these loci in 31 M. tuberculosis complex strains, 12 of them were found to display variations in tandem repeat copy numbers and, in most cases, sequence variations between repeat units as well. These features are reminiscent of those of certain human variable minisatellites. Of the 12 variable loci, only one was found to vary among genealogically distant BCG substrains, suggesting that these interspersed bacterial minisatellite-like structures evolve slowly in mycobacterial populations.

Base Sequence↗
PubMed2000

Isolation of an unusual Mycobacterium species from an AIDS patient with acute lymphadenitis.

A nonchromogenic Mycobacterium species was isolated from an AIDS patient with acute lymphadenitis. On the basis of the results of conventional tests, the strain appeared to be an atypical nonphotochromogenic Mycobacterium kansasii strain. Sequencing of the 16S rRNA gene revealed a unique nucleic acid sequence, suggesting that the isolate represents an undescribed pathogenic species.

AIDS-Related Opportunistic Infections↗
PubMed1999

Effect of adding clofazimine to combined clarithromycin-ethambutol therapy for Mycobacterium avium complex septicemia in AIDS patients.

This study compared the efficacies of clarithromycin-ethambutol and clarithromycin-ethambutol-clofazimine for the treatment of Mycobacterium avium complex (MAC) in AIDS patients. Thirty-four patients were randomized into two groups to receive clarithromycin 2 g/day and ethambutol 20 mg/kg/day, with or without clofazimine 200 mg/day. The evaluation was based primarily on blood cultures becoming negative after 2 months of therapy, but survival at 12 months and clinical evolution were also assessed. Inclusions were prematurely stopped because of a communication reporting increased mortality associated with clofazimine. At 2 months, the blood cultures of 55% of the clarithromycin-ethambutol group patients versus 81% of the clarithromycin-ethambutol-clofazimine group were negative; this difference is not significant (P=0.42). Only one relapse was observed during the study. No clarithromycin-resistant strain was isolated. No apparent difference in either survival or clinical evolution was observed in this small number of patients (median survival, 144 days in the clarithromycin-ethambutol group and 236 days in the clarithromycin-ethambutol-clofazimine group, P=0.44). The clarithromycin-ethambutol combination appears to be an effective and well-tolerated first-line therapy against MAC infections in AIDS patients.

AIDS-Related Opportunistic Infections↗
PubMed1999

Non-tuberculous mycobacterial tenosynovitis: a review.

The clinical characteristics, outcome and treatment of non-tuberculous mycobacterial tenosynovitis are reviewed. From lesions localized in the hand, 10 different species of non-tuberculous mycobacteria have been reported. The most common are Mycobacterium marinum and Mycobacterium kansasii. Other less frequent organisms are Mycobacterium avium complex, Mycobacterium szulgai, Mycobacterium terrae, Mycobacterium fortuitum, Mycobacterium chelonae, Mycobacterium abscessus, Mycobacterium malmoense and Mycobacterium xenopi. The infections appear to be the result of previous trauma, surgical procedure, corticosteroid injection or non-apparent inoculation (water contamination). Immunosuppression is sometimes associated with the infections and can be considered as a risk factor. Surgical debridement and appropriate mycobacterial cultures are critical to enable diagnosis and appropriate management. Specimens should be inoculated on a range of media and incubated at a range of temperatures in order to isolate mycobacteria with different growth characteristics (with prolonged incubation). The optimal treatment of these infections is discussed.

Hand↗
PubMed1999

Mycobacterium kansasii septic arthritis: French retrospective study of 5 years and review.

Septic arthritis due to Mycobacterium kansasii is rare; only 40 cases have been published. A French national inquiry revealed the occurrence of 10 new cases between 1992 and 1997 (8 men and 2 women: mean age, 37 years; range, 25-54 years). Seven had an underlying condition: AIDS (n=4), chronic skin psoriasis and AIDS (n=2), or a renal transplant (n=1). Trauma to the joint, use of intra-articular corticosteroid(s) 1 month to 2 years after the event, and chronic skin psoriasis were risk factors. The mean interval between appearance of the first symptoms of arthritis and the diagnosis was 5 months. Monarthritis was localized to the knee (n=4), wrist (n=3), finger (n=1), elbow (n=1), or ankle (n=1). The main diagnostic procedure was culture of a synovial biopsy specimen. In all cases, debridement was associated with antimycobacterial treatment. Three patients died of AIDS during treatment, and another is still undergoing treatment; the other 6 patients were cured. M. kansasii infection should be considered in all cases of indolent arthritis with any of the following risk factors: local trauma, local or systemic corticosteroid therapy, chronic skin psoriasis, and immunodepression, especially that due to human immunodeficiency virus infection.

Adolescent↗
PubMed1999

Comparative evaluation of ligation-mediated PCR and spoligotyping as screening methods for genotyping of Mycobacterium tuberculosis strains.

Spoligotyping has been suggested as a screening test in multistep genotyping of Mycobacterium tuberculosis strains. Relying on restriction fragment length polymorphism (RFLP) analysis with IS6110 (IS6110 RFLP analysis) as a "gold standard," we performed a comparative evaluation of spoligotyping and ligation-mediated PCR (LMPCR), a recently described PCR-based typing method, as rapid screening tests for fingerprinting of 158 M. tuberculosis strains collected in Verona, Italy. LMPCR seemed to be comparable to spoligotyping in terms both of feasibility with rapidly extracted DNA and of generation of software-analyzable images. Moreover, LMPCR grouped considerably fewer strains than spoligotyping (38 versus 67%) and was found to reduce the cluster overestimation rate (26.3 versus 58%) and to give a better discriminatory index (0.992 versus 0.970) compared to spoligotyping. In our geographical region, where there was no evidence of clustered strains carrying fewer than six IS6110 copies, LMPCR was found to be more discriminatory than spoligotyping. We also evaluated two models of three-step typing strategies, involving the use of spoligotyping and LMPCR as screening methods and IS6110 RFLP analysis as a further supporting test. LMPCR proved to be a more effective first-step test than spoligotyping, significantly reducing the need for subtyping. LMPCR should be considered an alternative to spoligotyping as a rapid screening method for M. tuberculosis fingerprinting, particularly in areas with a low prevalence of M. tuberculosis strains carrying few copies of IS6110.

DNA Transposable Elements↗
PubMed1999

hsp65 sequencing for identification of rapidly growing mycobacteria.

Partial sequencing of the hsp65 gene was used for the identification of rapidly growing mycobacteria (RGM). A 441-bp fragment (A. Telenti, F. Marchesi, M. Balz, F. Bally, E. Böttger, and T. Bodmer, J. Clin. Microbiol. 31:175-178, 1993) was amplified and sequenced by an automated fluorescence-based method involving capillary electrophoresis. Type strains of 10 RGM species were first studied. Each species had a unique nucleotide sequence, distinguishing it clearly from the other species. A panel of strains from the four main RGM species responsible for human infections, Mycobacterium abscessus, Mycobacterium chelonae, Mycobacterium fortuitum, and Mycobacterium peregrinum, was also studied. There were few sequence differences within each of these species (<2% of bases were different from the type strain sequence), and they had no effect on species assignment. hsp65 sequencing unambiguously differentiated M. chelonae and M. abscessus, two species difficult to identify by classical methods and 16S rRNA gene sequencing. The devised procedure is a rapid and reliable tool for the identification of RGM species.

Antigens, Bacterial↗
PubMed1999

Molecular markers demonstrate that the first described multidrug-resistant Mycobacterium bovis outbreak was due to Mycobacterium tuberculosis.

We genetically characterized multidrug-resistant Mycobacterium tuberculosis complex strains which caused a nosocomial outbreak of tuberculosis affecting six human immunodeficiency virus (HIV)-positive patients and one HIV-negative staff member (E. Bouvet, E. Casalino, G. Mendoza-Sassi, S. Lariven, E. Vallée, M. Pernet, S. Gottot, and F. Vachon, AIDS 7:1453-1460, 1993). The strains showed all the phenotypic characteristics of Mycobacterium bovis. They presented a high copy number of IS6110, the spacers 40 to 43 in the direct repeat locus, and the mtp40 fragment. They lacked the G-A mutation at position 285 in the oxyR gene and the C-G mutation at position 169 in the pncA gene. These genetic characteristics revealed that these were dysgonic, slow-growing M. tuberculosis strains mimicking the M. bovis phenotype, probably as a consequence of cellular alterations associated with the multidrug resistance. Spoligotyping and IS6110 restriction fragment length polymorphism (RFLP) analysis confirmed that the outbreak was due to a single strain. However, the IS6110 RFLP pattern of the strain isolated from the last patient, diagnosed three years after the index case, differed slightly from the patterns of the other six strains. A model of a possible genetic event is presented to explain this divergence. This study stresses the value of using several independent molecular markers to identify multidrug-resistant tubercle bacilli.

AIDS-Related Opportunistic Infections↗
PubMed1999

Mycobacterium kansasii infection in a Paris suburb: comparison of disease presentation and outcome according to human immunodeficiency virus status. Groupe dEtude Des Mycobactéries de la Seine-Saint-Denis.

SETTING: Department of Seine-Saint-Denis, France. OBJECTIVE: To compare the presentation and outcome of Mycobacterium kansasii infections according to human immunodeficiency virus (HIV) status. DESIGN: Retrospective analysis of all the medical charts of adults meeting the diagnostic criteria of the American Thoracic Society for M. kansasii infection between 1991 and 1995. RESULTS: Between 1991 and 1995, 35 cases (23 HIV-[6%] and 12 HIV+ [34%]) were found, giving an annual incidence of 0.5/100000. The following particularities were common to both groups: 1) frequency and prominence of respiratory and general symptoms, 2) rarity of clinically apparent extra-thoracic involvement, 3) bacteriological confirmation mostly obtained with respiratory tract specimens, 4) favourable bacteriological outcome, and 5) low mortality attributable to the mycobacterial infection. The most striking differences concerned chest radiography: HIV- patients had apical cavitated and nodular lesions, while HIV+ patients exhibited a variety of other patterns, including alveolar infiltrates, miliary lesions and/or thoracic lymphadenopathy. CONCLUSION: Apart from pulmonary radiographic differences, presentation and short-term outcome of M. kansasii infections were similar in HIV+ and HIV-patients.

Adult↗