1,721,191 research outputs found
Microbiology and diagnosis of tuberculosis
No full textMajor features of Mycobacterium tuberculosis as the slow metabolism and the large amount of lipid in the outer layer of the cell wall, shown by acid-fast staining, are responsible for its peculiar morphology and pathogenicity. For correct diagnosis of M. tuberculosis infection, direct microscopy of the pathological sample, isolation and identification on suitable culture media of the microorganism and in vitro tests of antituberculous drug sensitivity are required. Alternative time-sparing methods have been proposed: the radiometric system is the most important; other manual or automated systems as indicators of mycobacterial growth have been developed, while the new methods of rapid identification as high-performance liquid chromatography (HPLC) cannot be used as a routine for the high cost of equipment
Polymerase chain reaction and other molecular techniques used in the diagnosis of tuberculosis
No full textThe new techniques of molecular biology using nucleic acid probes and genic amplification as the ligase chain reaction and the polymerase chain reaction, are routinely used for the detection and rapid identification of M. tuberculosis. The higher costs of these methods as compared to the conventional biochemical test is compensated for because rapid identification allows early implementation of prevention measures
Impact of Structural Domains of the Heparin Binding Hemagglutinin of Mycobacterium tuberculosis on Function
No full textAmong the few well characterized virulence factors of Mycobacterium tuberculosis (Mtb) is the heparin-binding hemagglutinin (HBHA). HBHA is a 21-kDa protein that localizes to the mycobacterial surface where it can interact with host components. Interaction with epithelial cells and components of the extracellular matrix is mediated by the methylated lysine-rich C-terminal domain of the protein. The N-terminal end of HBHA contains a coiled coil motif which is involved in protein oligomerization and bacterial-bacterial aggregation. In this report, we will focus our attention on what is known about the structure of the HBHA protein and the protein function and role in TB pathogenesis
Osteoradionacrosis of the jaws. Therapeutic approach [Approccio terapeutico all'osteoradionecrosi delle ossa mascellari]
No full textScopo del lavoro. Tra i vari tipi di affezioni che possono colpire le ossa mascellari, l’osteoradionecrosi è fra le più complesse dal
punto di vista dell’approccio terapeutico per il tipo di modificazioni che la terapia radiante attua nei confronti delle strutture ossee. Con il presente lavoro gli autori vogliono fare il punto in tema di gestione del paziente che dovrà subire, sta subendo o ha già subito uno o più trattamenti radioterapeutici.
Materiali e metodi. Si accennano le varie opzioni terapeutiche e si presenta un caso di osteoradionecrosi trattato con successo con terapia chirurgica e conservativa.
Risultati e conclusioni. La radioterapia consente un buon controllo dell’accrescimento delle proliferazioni neoplastiche del cavo
orale; tuttavia l’osteoradionecrosi, uno dei suoi più temuti effetti collaterali, può portare alla perdita di vasti segmenti ossei. In questi casi può essere di aiuto, pur non essendo risolutiva, l’ossigenoterapi
Microbiological and immunological diagnosis of tuberculous spondylodiscitis
No full textTuberculous spondylodiscitis is one the many manifestations of active tuberculosis (TB) and can result following primary infection or, more frequently, from reactivation of active TB in subjects with latent TB. Definitive diagnosis of tuberculous spondylodiscitis requires the identification of Mycobacterium tuberculosis in the biological sample following microbiological analysis
Molecular epidemiology of Mycobacterium tuberculosis strains isolated from different regions of Italy and Pakistan
No full textThe use of the (GTG)5 oligonucleotide, a repetitive marker in the Mycobacterium tuberculosis chromosome, as a primer in association with an IS6110 outlooking primer has been successfully applied to a PCR-based fingerprinting method. This method classified 62 strains of M. tuberculosis, isolated from human immunodeficiency virus-seropositive and -seronegative patients in different regions of Italy and Pakistan, as having 53 different patterns. The results were compared with traditional IS6110 fingerprinting, by which 47 distinct patterns were observed
Assessment of linezolid resistance mechanisms among Staphylococcus epidermidis causing bacteraemia in Rome, Italy
No full textOBJECTIVES: To characterize linezolid resistance among blood cultured Staphylococcus epidermidis from patients at the Polyclinic Agostino Gemelli (2006-08). Isolates also showed elevated MICs of macrolide, lincosamide and streptogramin (MLS) compounds, which were investigated.
METHODS: Ten S. epidermidis exhibiting linezolid MICs ≥ 4 mg/L were included. Isolates were screened for cfr mutations in 23S rRNA, L3, L4 and L22, and MLS genes by PCR/sequencing. Ribosomal proteins were compared with those from a linezolid-susceptible (MIC, 1 mg/L) clinical strain and ATCC 12228. cfr location was determined by Southern blot/hybridization. The cfr strain was submitted to plasmid curing. Epidemiology was assessed by PFGE and multilocus sequence typing (MLST).
RESULTS: S. epidermidis displayed linezolid MICs of 4 or 8 mg/L, except for strain 4303A (MIC, 64 mg/L). These organisms and a linezolid-susceptible strain exhibited L3 Leu101Val compared with ATCC 12228. Isolates also showed L3 Phe147Leu and Ala157Arg, and L4 Asn158Ser. Strain 12375A possessed L4 Lys68Arg. Isolates were wild-type for 23S rRNA and L22. cfr was plasmid located in strain 4303A and the plasmid-cured strain exhibited a linezolid MIC (4 mg/L) similar to that for cfr-negative strains (4-8 mg/L). All organisms harboured erm(A) and msr(A), while vga(A) was detected in several isolates. All isolates were clonally related and ST-23.
CONCLUSIONS: L3 Phe147Leu and/or Ala157Arg appeared responsible for the elevated linezolid MIC, since adjacent alterations have been associated with resistance. L4 Asn158Ser has been reported in a linezolid-susceptible isolate and Lys68Arg detected here did not seem to provide an additive effect. Acquisition of cfr markedly increased (8- to 16-fold) the linezolid MICs. vga(A) was associated with higher MICs of quinupristin/dalfopristin and retapamulin
Variable expression patterns of Mycobacterium tuberculosis PE_PGRS genes: evidence that PE_PGRS16 and PE_PGRS26 are inversely regulated in vivo
No full textEvaluation of expression of 16 PE_PGRS genes present in Mycobacterium tuberculosis under various growth conditions demonstrated constitutive expression of 7 genes, variable expression of 7 genes, and no expression of 2 genes. An inverse expression profile for genes PE_PGRS16 and PE_PGRS26 was observed to occur in macrophages and in mice infected with M. tuberculosis. Variable expression of PE_PGRS proteins could have implications for their role in the immunopathogenesis of tuberculosis
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