Evaluation of an immunochromatographic assay for rapid identification of Mycobacterium tuberculosis complex in clinical isolates.

Identification of Mycobacterium tuberculosis complex (MTC) remains slow. Over the years, several new technologies have been proposed to accelerate and simplify the detection of MTC. In this context, we evaluated an immunochromatographic assay (ICA) (BIO-LINE SD Ag MPT64 TB) for rapid identification of MTC, based on detection of a specific MPT64 antigen of MTC. We have tested it on i) mycobacterial cultures: 210 MTC strains and 28 nontuberculous mycobacteria; ii) M. bovis bacille Calmette-Guérin strain SSI (Statens Serum Institut, Denmark); and iii) 22 microorganisms other than mycobacteria, isolated from cultures. We concluded that this kit has an excellent specificity (100%) and sensitivity (99%) from isolated cultures. The ICA (BIO-LINE SD Ag MPT64 TB) allows excellent MTC identification from clinical isolates. It is a rapid, simple, and inexpensive test, and has a definite contribution in the rapid laboratory diagnosis of tuberculosis.

Evaluation of the diagnostic value of measuring IgG, IgM, and IgA antibodies to mycobacterial A60 antigen in active tuberculosis.

The purpose of the present study was to evaluate the clinical usefulness of detection of serum immunoglobulin A (IgA), IgG, and IgM antibodies raised against the mycobacterial A60 antigen for the diagnosis and discrimination of active tuberculosis (TB) from other pulmonary diseases. Three commercially available ELISA kits (IgA, IgG, and IgM) (ANDA Biologicals, Strasbourg, France) were evaluated simultaneously in 246 serum samples from 3 groups of patients: group I, 171 patients with active TB (128 pulmonary TB and 43 extrapulmonary TB); group II, 73 patients with pulmonary non-TB diseases; and group III, 2 leprosies patients. The sensitivities of tests ranged from 31.3% (IgA) to 94% (IgG) in pulmonary TB patients and from 21% (IgA) to 84% (IgG) in extrapulmonary TB patients. The specificities of assays varied from 92% (IgG) to 96% (IgA) in the pulmonary non-TB group. Combination of IgG with IgA and/or IgM does not improve its sensitivity. Clinical use of the A60-based serodiagnostic IgG assay is of great value for the rapid diagnosis and discrimination between active TB and pulmonary non-TB diseases. Moreover, this test could be used to increase diagnostic accuracy, especially for smear-negative TB cases, which are difficult to diagnose.

Rapid detection of Mycobacterium tuberculosis in sputum by Patho-TB kit in comparison with direct microscopy and culture.

The usefulness of a new rapid diagnostic test (Patho-TB) using antibodies specific to mycobacterial antigens was evaluated for the rapid discrimination between pulmonary tuberculosis (TB) and non-TB pulmonary diseases on sputa. One hundred sputa collected from 79 active TB patients and from 21 patients with non-TB pulmonary diseases (asthma and chronic obstructive pulmonary disease) were enrolled into the study and tested for the presence of Mycobacterium tuberculosis by Ziehl-Neelsen smear, Patho-TB kit, and Löwenstein-Jensen culture. The sensitivity, specificity, positive predictive value, and negative predictive value of the Patho-TB test were 95%, 100%, 100%, and 84%, respectively. Patho-TB test is simple, quick, and easy to perform. Its sensitivity, specificity, and positive predictive value are satisfactory. Therefore, it could be used as a screening test in poorly equipped laboratories of TB endemic areas.

[Clinical, epidemiologic and bacteriological characteristics of urinary tract infections due to Staphylococcus saprophyticus in the central part of Tunisia]. / Caractéristiques cliniques, épidémiologiques et bactériologiques des infections urinaires à Staphylococcus saprophyticus dans le centre de la Tunisie.

AIM: We assess the clinical, epidemiologic and bacteriological aspects of urinary tract infections due to S. saprophyticus through a sample collected in the central part of Tunisia. METHODS: Retrospective study, related to 92 strains of S. saprophyticus, isolated among positive urinary specimens in 2006. Considered data were: sex, age, original departments, symptoms, type of urinary tract infection, diagnosis date and susceptibility of strains to antibiotics. RESULTS: Patients are young women in 98% (average age: 31.5 years) with cystitis in 99%. They are outpatients in 90%. S. saprophyticus represents 2.8% of all uropathogens; it is the first cocci with positive Gram (28.2%). Any seasonal variation is noticed. S. saprophyticus has shown higher susceptibility to antibiotics than other staphylococci; cotrimoxazole, fluoroquinolons and nitrofurans represent the best treatment. CONCLUSION: S. saprophyticus is responsible of cystitis in young women. There is no seasonal variation in our area. This community staphylococci is very susceptible to antibiotics.