Identification of the newly described Mycobacterium poriferae from tuberculous lesions of snakehead fish (Channa striatus).

A mycobacterium isolated form a cultured snakehead with nodular lesions was identified on the basis of high performance liquid chromatography (HPLC) profile of cell wall mycolic acids, and confirmed by conventional tests, as Mycobacterium poriferae, a species previously isolated only from a marine sponge. The profiles of M. poriferae, Mycobacterium aurum and Mycobacterium parafortuitum are here reported for the first time.

Determination of mercury in urine by ET-AAS using complexation with dithizone and extraction with cyclohexane.

A precise and accurate graphite furnace atomic absorption spectrometric method for the determination of mercury in urine was developed. Samples were subjected to hydrolysis with nitric acid. Then, mercury in the sample was complexed by dithizone and extracted by cyclohexane. Mercury concentrations were determined against a urinematched calibration curve. Coated graphite notched partition tubes (Varian) and forked pyrolytic platforms (Varian) were used. The detection limit of the method (x(blank) + 3 SD(blank)) was 1 mug 1(-1). The between run precision CV's were 4.7 and 3.4% for urine with a mercury concentration of 48.2 and 156.2 mumol 1(-1), respectively; the within run precision CV's were 8.9 and 2.9% for urine with a mercury concentration of 17.0 and 172 mug 1(-1), respectively.

Investigation on several phenotypic features in two strains of Mycobacterium genavense.

The newly recognized species Mycobacterium genavense causes disseminated infections in AIDS patients, but its prevalence is difficult to assess because of its inability to grow on standard solid media. For the same reason, very little is known about the phenotypic traits of its isolates. We report here the results of our studies on two such strains isolated from AIDS patients and subcultured on a non-standard solid medium. Besides several features conventionally explored for mycobacterial speciation, we tested the isolates for 19 enzymatic activities and determined their mycolic acids profiles by means of high performance liquid chromatography. We also compare our findings with the scanty literature data on the laboratory characteristic and antimicrobial susceptibility of M. genavense.

[The simultaneous determination of hippuric acid, o-, m-, p-methylhippuric acids, mandelic acid and phenylglyoxylic acid in urine by HPLC]. / Determinazione simultanea di acido ippurico, acidi o-, m-, p-metilippurici, acido mandelico e acido fenilgliossilico nelle urine mediante HPLC.

A high-performance liquid chromatographic method is described for the simultaneous determination of six metabolites of aromatic hydrocarbons: hippuric acid (HA) from toluene; o-, m-, p-methylhippuric acids (o-, m-, p-MHA) from xylene; mandelic acid (MA) and phenylglyoxylic acid (PGA) from styrene and ethylbenzene. Metabolites were first extracted from urine by solid phase extraction with anion exchange resin, then isocratically separated on a C8 column with 3 microns particle size, 10 cm length and 3 mm internal diameter. Mobile phase was prepared diluting 16 mL of tetrahydrofuran, 14 mL of acetronitrile and 5 mL of methanol to 500 mL with phosphoric acid/potassium dihydrogen phosphate buffer 0.01 M (pH 2.7). The internal standard was 3-hydroxybenzoic acid. Chromatographic runs were completed in about 21 min. The accuracy and reproducibility obtained make this method useful for the biological monitoring of occupational exposure to toluene, xylene, styrene and ethylbenzene.

Utility of high-performance liquid chromatography for identification of mycobacterial species rarely encountered in clinical laboratories.

High-performance liquid chromatography (HPLC) has been demonstrated to be a suitable technique for determining the species of mycobacteria on the basis of their mycolic acid pattern. Representative HPLC profiles, which are needed for the visual recognition of chromatograms, have been published for the most frequently encountered mycobacterial species. No extensive study has been reported for less common species, and only a few, scattered chromatographic patterns are available in literature. This study evaluates the utility of this technique for the identification of several rare species. Mycobacterium celatum, Mycobacterium genavense and Mycobacterium simiae chromatographic profiles have been verified, and previously unreported profiles of other species investigated. The chromatographic pattern of Mycobacterium malmoense is presented for the first time.

Isolation of the newly described species Mycobacterium celatum from AIDS patients.

Mycobacterium celatum is a recently described species which, on the basis of conventional tests, may be misidentified as Mycobacterium xenopi or as belonging to the Mycobacterium avium complex. Only genomic sequencing or high-performance liquid chromatography of cell wall mycolic acids can presently allow a correct identification of this mycobacterium. Two cases of infection due to M. celatum, in AIDS patients, are described here. The quantitative susceptibility pattern of the isolates to a wide spectrum of drugs is also reported.

Cervical lymphadenitis due to an unusual mycobacterium.

A scotochromogenic acid-fast bacillus was isolated from a lymph node of a 2-year-old female. On the basis of conventional testing, the mycobacterium appeared to be Mycobacterium scrofulaceum. Its mycolic acid profile, however, was not identical to that of Mycobacterium scrofulaceum but was similar to that of Mycobacterium interjectum. Direct sequencing of the 16S rRNA gene revealed a unique nucleic acid sequence, suggesting that the isolate represents a previously undescribed pathogenic species.

Isolation of an unusual mycobacterium from an AIDS patient.

A mycobacterium isolated from a clinical sample of an AIDS patient was identified as Mycobacterium interjectum by direct 16S rRNA sequence determination. High-performance liquid chromatography, however, revealed a mycolic acid pattern which was different from the one shared by the previously analyzed strains of this species.

Characterization of an isolate of the newly described species Mycobacterium interjectum.

The phenotypic features of a clinical isolate of the new species Mycobacterium interjectum, identified on the basis of its 16S rRNA gene sequence, are compared with those of the type strain. The differentiation of M. interjectum from Mycobacterium gordonae or Mycobacterium scrofulaceum is not achievable on the basis of phenotypic traits usually tested for mycobacterial speciation, but it can be reached by 16S rRNA gene sequencing or by high performance liquid chromatography (HPLC) of cell wall mycolic acids. The former reveals sequence identity with the signature region of the type species, and the latter yields a profile which is easily differentiated from those of the other two species. The unique HPLC profile of M. interjectum is reported here for the first time and so are the MICs of a wide spectrum of drugs.

Mycobacterium malmoense in Italy: the modern Norman invasion?

The isolation of Mycobacterium malmoense has for a long time been restricted to few countries of Northern Europe; reports from countries other than Sweden, Great Britain and Finland are rare and the first Italian case report has been published in 1995. Since 1988, however, fifteen strains of M. malmoense have been isolated in Italy, eleven of which in the last two years; of these, ten appeared clinically significant on the basis of medical records. The susceptibility of the strains and the role of high performance liquid chromatography of cell wall mycolic acids for a reliable identification are discussed.

Characterization of mycobacterial isolates phylogenetically related to, but different from Mycobacterium simiae.

The use of high-performance liquid chromatography (HPLC) revealed four previously unreported profiles within a group of mycobacteria consisting of 14 clinical isolates. These mycobacteria, whose identification by conventional tests appeared problematic, mostly resembled Mycobacterium avium complex or Mycobacterium simiae. Genetic analysis revealed, within this group, six different nucleic acid sequences in a hypervariable 16S rRNA segment, but all the isolates appeared to be phylogenetically related to M. simiae. Six isolates representing the largest of groups defined by means of genetic sequencing turned out to belong to the newly described species Mycobacterium lentiflavum. Furthermore, three such clusters precisely coincided with three of those defined by HPLC, while the three remaining clusters shared almost identical HPLC profiles. All but one strain (which, although clearly not belonging to the M. avium complex, hybridized with specific commercial DNA probes) showed high-grade resistance to the majority of antimycobacterial drugs. Three of the isolates were clinically significant according to stringent criteria. Sophisticated techniques, like genetic sequencing or HPLC, by now seem indispensable for differentiating unusual and new mycobacteria from well-established ones.