-
Journal of Clinical Microbiology Apr 1997A previously described PCR-restriction fragment length polymorphism (RFLP) identification schema for Nocardia that used an amplified 439-bp segment (amplicon) of the...
Rapid identification of clinically significant species and taxa of aerobic actinomycetes, including Actinomadura, Gordona, Nocardia, Rhodococcus, Streptomyces, and Tsukamurella isolates, by DNA amplification and restriction endonuclease analysis.
A previously described PCR-restriction fragment length polymorphism (RFLP) identification schema for Nocardia that used an amplified 439-bp segment (amplicon) of the 65-kDa heat shock protein gene was evaluated for potential use with isolates of all clinically significant aerobic actinomycetes. The study included 28 reference (American Type Culture Collection) strains and 198 clinical isolates belonging to 20 taxonomic groups. Of these 198 isolates, 188 could be differentiated by this PCR-RFLP method. Amplicons from all aerobic actinomycete isolates lacked BstEII recognition sites, thereby distinguishing them from those of mycobacteria that contain one or more such sites. Of 29 restriction endonucleases, MspI plus HinfI produced RFLP patterns that differentiated 16 of the 20 taxa. A single RFLP pattern was observed for 15 of 20 taxa that included 65% of phenotypically clustered isolates. Multiple patterns were seen with Gordona bronchialis, Nocardia asteroides complex type VI, Nocardia otitidiscaviarum, Nocardia transvalensis, and Streptomyces spp. Streptomyces RFLP patterns were the most heterogeneous (five patterns among 19 isolates), but exhibited a unique HinfI fragment of > 320 bp. RFLP patterns that matched those from type strains of Streptomyces albus, Streptomyces griseus, or Streptomyces somaliensis were obtained from 14 of 19 Streptomyces isolates. Only 10 of 28 isolates of N. otitidiscaviarum failed to yield satisfactory amplicons, while only 6 of 188 (3.2%) clinical isolates exhibited patterns that failed to match one of the 21 defined RFLP patterns. These studies extended the feasibility of using PCR-RFLP analysis as a rapid method for the identification of all clinically significant species and taxa of aerobic actinomycetes.
Topics: Actinomyces; Bacterial Typing Techniques; DNA, Bacterial; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length
PubMed: 9157134
DOI: 10.1128/jcm.35.4.817-822.1997 -
PLoS Neglected Tropical Diseases Sep 2008Mycetoma is a chronic infectious disease of tropical and subtropical countries. It is produced by true fungi and actinobacteria. In México, Nocardia brasiliensis is the...
BACKGROUND
Mycetoma is a chronic infectious disease of tropical and subtropical countries. It is produced by true fungi and actinobacteria. In México, Nocardia brasiliensis is the main causative agent of mycetoma, producing about 86% of the cases; the gold standard for the therapy of mycetoma by N. brasiliensis is the use of sulfonamides which give a 70% cure rate. The addition of amikacin to this regime increases to 95% the cure rate; however, the patients have to be monitored for creatinine clearance and audiometry studies because of the potential development of side effects. Because of that it is important to search for new active compounds. In the present work, we evaluated the in vivo effect of DA-7867, an experimental oxazolidinone, on the development of experimental mycetomas by N. brasiliensis in BALB/c mice.
METHODOLOGY/PRINCIPAL FINDINGS
In order to determine the optimal dose utilized to apply to the animals, we first determined by HPLC the plasma levels using several concentrations of the compounds. Based on these results, we used 10 and 25 mg/kg subcutaneously every 24 hr; DA-7867 was also supplied in the drinking water at a calculated dose of 25 mg/kg. As a control we utilized linezolid at 25 mg/kg, a compound active in murine and human infections, three times a day. The mice were infected in the right footpad with a young culture of N. brasiliensis HUJEG-1, and one week later we started the application of the antimicrobials for six more weeks. After that we compared the development of lesions in the groups injected with saline solution or with the antimicrobials; the results were analyzed by the variance ANOVA test. DA-7867 was able to reduce the production of lesions at 25 mg/kg, when given either subcutaneously or in the drinking water.
CONCLUSIONS/SIGNIFICANCE
The experimental oxazolidinone DA-7867 is active in vivo against N. brasiliensis, which opens the possibility of using this drug once it is accepted for human application. Since oxazolidinones seem to be active against a wide spectrum of actinobacteria, it is possible they could be used in human cases of mycetoma by other actinomycetales, such as Streptomyces somaliensis, highly prevalent in Sudan, or Actinomadura madurae and A. pelletieri, which are commonly observed in Africa and India.
Topics: Actinomycetales Infections; Africa; Animals; Anti-Infective Agents; Chromatography, High Pressure Liquid; Humans; India; Mice; Mice, Inbred BALB C; Nocardia Infections; Oxazolidinones
PubMed: 18820738
DOI: 10.1371/journal.pntd.0000289