Léa Lebrun

Use of the INNO-LiPA-MYCOBACTERIA Assay (Version 2) for Identification of Mycobacterium avium-Mycobacterium intracellulare-Mycobacterium scrofulaceum Complex Isolates

ABSTRACT Using INNO-LiPA-MYCOBACTERIA (Lipav1; Innogenetics) and the AccuProbe (Gen-Probe Inc./bioMérieux) techniques, 35 Mycobacterium avium-Mycobacterium intracellulare-Mycobacterium scrofulaceum (MAC/MAIS) complex strains were identified between January 2000 and December 2002. Thirty-four of 35 isolates were positive only for the MAIS complex probe by Lipav1 and were further analyzed by INNO-LiPA-MYCOBACTERIA version 2 (Lipav2), hsp65 PCR restriction pattern analysis (PRA), and ribosomal internal transcribed spacer (ITS), hsp65, and 16S rRNA sequences. Lipav2 identified 14 of 34 strains at the species level, including 11 isolates positive for the newly specific MAC sequevar Mac-A probe (MIN-2 probe). Ten of these 11 isolates corresponded to sequevar Mac-A, which was recently defined as Mycobacterium chimerae sp. nov. Among the last 20 of the 34 MAIS isolates, 17 (by hsp65 PRA) and 18 (by hsp65 sequence) were characterized as M. avium. Ten of the 20 were identified as Mac-U sequevar. All these 20 isolates were identified as M. intracellulare by 16S rRNA sequence except one isolate identified as Mycobacterium paraffinicum by 16S rRNA and ITS sequencing. One isolate out of 35 isolates that was positive for M. avium by AccuProbe and that was Mycobacterium genus probe positive and MAIS probe negative by Lipav1 and Lipav2 might be considered a new species. In conclusion, the new INNO-LiPA-MYCOBACTERIA allowed the identification of 40% of the previously unidentified MAIS isolates at the species level. The results of the Lipav2 assay on the MAIS isolates confirm the great heterogeneity of this group and suggest the use of hsp65 or ITS sequencing for precise identification of such isolates.

Ralstonia pickettii Traced in Blood Culture Bottles

ABSTRACT Over a 9-month period, 14 strains of Ralstonia pickettii were isolated from various biological samples inoculated in a blood culture medium. Molecular epidemiological investigation confirmed the relatedness of the strains. The source of the contamination proved to be the blood culture bottle caps.

Use of INNO-LIPA assay for rapid identification of mycobacteria.

Using 106 clinical isolates of mycobacteria, we showed that INNO-LIPA Mycobacteria assay is an excellent tool to rapidly identify the most frequently isolated nontuberculous mycobacteria, in one procedure. It may be used as an additional technique to AccuProbe assay, which remains the fastest and the cheapest tool for a rapid and accurate identification of the M. tuberculosis complex.

Human seminal plasma suppresses the chemiluminescence of polymorphonuclears without modifying phagocytosis.

ABSTRACT: The suppressive activity of human seminal plasma was confirmed on the luminol‐amplified chemiluminescent reaction of human polymorphonuclears. This suppression was found to be dose‐dependent and noncytotoxic. The responsible factor appeared to be a radical scavenger of low molecular weight, acting selectively on hydrogen peroxide. Correlation with glandular markers of semen indicated this molecule to have a prostatic origin. Neither crude seminal plasma nor this factor were found to suppress intracellular engulfment and killing of bacteria. This molecule seems to cooperate with the other semen antioxidants to protect sperm cells from extracellular oxygen radicals.

A critical study of the use of staphylococci containing protein A for separation of IgG and IgM antibodies

This study was to determine the best conditions for using staphylococci bearing protein A to separate IgG from IgM. The validity of the technique was evaluated for detection of IgM with antimicrobial activity and for typing monoclonal IgM. The results indicate that separation of IgG and IgM is not entirely satisfactory in normal sera and worse in hyperglobulinemic sera. The detection and titration of IgM antimicrobial antibodies (rubella and hepatitis B core (HBc) specific IgM) was unreliable because IgG was only partially absorbed by staphylococcal cells, while a significant portion of IgM was bound. The use of higher concentrations of staphylococci did not improve the results because the more IgG was absorbed, the more IgM was also bound. It is shown that with anti-HBc specific IgM the risk of misinterpretation is very high with a sensitive radioimmunoassay technique allowing detection of trace amounts of nonabsorbed IgG. In contrast staphylococcal protein A proved useful in typing monoclonal IgM.

Detection of Legionella pneumophila antigenby elisa in urine of experimentally infected guinea-pigs

Guinea-pigs were experimentally infected with Legionella pneumophila. L. pneumophila antigen was detected in urine samples by a double antibody sandwich ELISA. Urinary antigen was present from the beginning of the acute phase of the disease. In two out of five cases, this antigen was found with no antibody detectable in sera by indirect immunofluorescence staining.