New antimycobacterial 2,3-dihydro-1-alkylindole-2-thiones

A series of 2,3-dihydroindole-2-thiones was evaluated for in vitro antimycobacterial activity against Mycobacterium tuberculosis, M. kansasii, M. fortuitum, two strains of M. intracellulare and three strains of M. avium. 2,3-Dihydro-1-methyl-2-thioxoindole-3-one and 2,3-dihydro-1-butyl-2-thioxoindole-3-one were the most active substances against potentially pathogenic strains, being more active than isoniazide.

New antimycobacterialS-alkylisothiosemicarbazones

In connection with a systematic study of antimycobacterial agents against potentially pathogenic strains the series of 12 S-alkylisothiosemicarbazones was evaluated for in vitro antimycobacterial activity against Mycobacterium tuberculosis, M. kansasii, M. fortuitum, two strains of M. intracellulare and three strains of M. avium. Quinoline-4-carbaldehyde-S-hexyl-isothiohydrazone was found to be more active against potentially pathogenic strains than isoniazide.

[External quality control system in medical microbiology and parasitology in the Czech Republic]

The External Quality Control System (EQAS) of laboratory activities in medical microbiology and parasitology was implemented in the Czech Republic in 1993 with coded sera samples for diagnosis of viral hepatitis and bacterial strains for identification distributed to first participating laboratories. The number of sample types reached 31 in 2003 and the number of participating laboratories rised from 79 in 1993 to 421 in 2003. As many as 15.130 samples were distributed to the participating laboratories in 2003. Currently, almost all microbiology and parasitology laboratories in the Czech Republic involved in examination of clinical material participate in the EQAS. Based on the 11-year experience gained with the EQAS in the Czech Republic, the following benefits were observed: higher accuracy of results in different tests, standardisation of methods and the use of most suitable test kits.

[Multiresistant tuberculosis in the Czech Republic (1999-2001)]

BACKGROUND

Multidrug-resistant (MDR) tuberculosis, defined as a disease caused by Mycobacterium tuberculosis strains, which are resistant to more antituberculous drugs (at least to isoniazid and rifampicin), is a problem frequently discussed in the Czech Republic. Cases of specific disease refractive to causal antituberculous therapy are associated with the risk of the spread of the causative agent among the population.

METHODS AND RESULTS

The National Reference Laboratory for Mycobacteria collected 2813 Mycobacterium tuberculosis strains isolated by Czech mycobacteriological laboratories in 1999 to 2001. All strains were tested for susceptibility to basic antituberculous drugs and then the MDR strains were further tested for susceptibility/resistance to other antituberculous and antibacterial drugs. The MDR strains were studied by DNA analysis (DNA fingerprinting restriction analysis, RFLP-Restriction Fragment Length Polymorphism) as well. Thirty-nine patients who had MDR tuberculosis were excretors of 56 Mycobacterium tuberculosis strains. In average, MDR tuberculosis accounted for 1.96% (1.7-2.4) of all cases of bacillary tuberculosis. The most frequent type of the multidrug resistance was that resistant to four basic antituberculous drugs (isoniazid, rifampicin, ethambutol and streptomycin). It was confirmed in 48.2% multidrug resistant strains.

CONCLUSIONS

Isepamicin, clofazimin, capreomycin and amikacin are considered to be the most promising antituberculosis drugs. Based on RFLP profiles, 61.5% of strains were placed into 8 clusters while the other strains remained unclustered. No significant differences in geographical distribution and population structure were found between the excretors of clustered strains and those of unclustered strains. Preliminary comparison with restriction profiles of the MDR Mycobacterium tuberculosis strains in the international database suggests the uniqueness of Czech strains showing the profiles not found elsewhere to date.

The Czech External Quality Control system in medical microbiology and parasitology

The External Quality Control (EQC) system in activities of laboratories engaged in medical microbiology and parasitology was established in the Czech Republic in 1993 when to the first laboratories which applied coded serum samples were sent for diagnosis of viral hepatitis and bacterial strains for identification. In the course of years the number of control areas increased and in 2000 there were 31 and the number of those interested in participation in EQC increased from 79 in 1993 to 434 in 2000. This year a total of 13,239 samples will be sent to laboratories. Gradually thus almost all microbiological and parasitological laboratories concerned with examination of clinical material became involved. Seven-year experience with EQC in the Czech Republic revealed that gradually the results of various examinations became more accurate, that methods became standardized and the most suitable examination sets are used.

Quinazoline derivatives with antitubercular activity

4-Quinazolinol was prepared by the reaction of anthranilic acid and formamide. The hydroxy group was converted into the thiol function by treatment with phosphorus(V)sulfide, and the subsequent alkylation of the thiol group was carried out with alkylhalides under the conditions of phase-transfer catalysis. The structure of the substances was confirmed by 1H, 13C NMR, IR, and MS. Most of the synthesized compounds exhibited antimycobacterial activity against the strains of Mycobacterium tuberculosis, Mycobacerium avium, Mycobacterium fortuitum, Mycobacterium kansasii and Mycobacterium intracellulare. 4-(S-Butylthio)quinazoline (3c) was even more active than isoniazide against atypical strains of mycobacteria.

Plesiomonas shigelloides in water and fish

Plesiomonas shigelloides strains isolated from aquariums, surface water and fish were serotyped using the international antigenic scheme and a provisional scheme designed for environmental strains, called the "Schubert" scheme. A remarkable variety of serovars represented in both schemes was found, namely in surface water samples and in fish.

Mycobacterial infections in patients with AIDS in a low HIV prevalence area

The Czech Republic is characterized here as both a low HIV prevalence area (1.64 registered positivity per 10(5) population and 45 AIDS patients notified in the 1986-93 period) and a low tuberculosis prevalence area (mortality rate 0.8, incidence of bacillary pulmonary cases 11.3 per 10(5) population and risk of infection 0.04 in 1990). From 1986 to 1993 a total of 10 cases of mycobacterial infections complicating AIDS or ARC disease were registered in the Czech Republic in 9 male patients aged from 29 to 55, 8 homosexuals, and one woman aged 48. Classical pulmonary tuberculosis caused by M. tuberculosis was diagnosed in one male patient and was controlled by antituberculosis chemotherapy. The remaining mycobacterial infections were caused by the following opportunistic mycobacterial pathogens. (a) M. avium in five individuals, four of them died of a disseminated disease; (b) M. kansasii--in two patients, one died of a disseminated infection; (c) M. xenopi--involved in a fatal generalized CMV, and cryptococcal and mycobacterial infection; (d) M. fortuitum caused a generalized disease in a case of exhaustive multifocal encephalopathy. Authors conclude that under conditions of low prevalence of both HIV and tuberculosis infection the risk to AIDS patients of contracting classical tuberculosis is low. A relatively frequent occurrence of non-tuberculosis mycobacterial disease in AIDS patients afflicted with the impaired immunity is explained by transmission of opportunistic mycobacteria from the environment.

Water as a possible factor of transmission in mycobacterial infections

Mycobacterium kansasii and Mycobacterium xenopi are the most frequent species occurring in water in the Czech Republic. In the endemic area of M. kansasii in heavy industry and mining areas of North Moravia various mycobacterial species were detected in more than 20% of different water samples and M. kansasii was found in 1.5 to 1.9% of them, frequently in pit bathrooms and in the drinking water as well. Mycobacterium xenopi was detected in 35 and 50% of water samples collected in households of M. xenopi excretors in North Bohemia and in Prague. A nosocomial occurrence of M. xenopi was recorded in an hospital department in North Bohemia and in a rest home in Prague and all samples of water from the afflicted institutions were positive for M. xenopi. In a coal mine in Moravia a case of cutaneous involvement associated with the presence of M. marinum in mine water was also recorded. The incidence of various mycobacterial species (except of M. kansasii and M. xenopi) in spa and swimming pools in West Bohemia reached 35% positivity. Comprehensive reviews of bacteriological investigations for mycobacteria performed in the entire territory of the Czech Republic have been reported in annual reports since 1985. In the period from 1985 to 1991 a total of 5167 samples of various kinds of water samples were examined and mycobacteria were detected in 8.2 to 47.7% of them.

[Drug resistance in M. tuberculosis in Prague 1987-1992]

In 1987-1992 in Prague drug resistance of M. tuberculosis to four standard antituberculotics (isoniazide, streptomycin, rifampicin, ethambutol) was recorded in 39 patients, i.e. in 1.5-5% of patients with bacillary tuberculosis. Initial resistance was found in 25, secondary resistance in 13 subjects, in one patient both types of resistance were observed. In both groups men and patients born before 1941 predominated. In patients with initial resistance findings rated as small or medium-sized predominated, while in secondary resistance half the findings were medium-sized or extensive; an extrapulmonary form was recorded in one female patient. In the group of patients with an initially resistant M. tuberculosis monoresistant strains predominated and the highest ratio was accounted for by strains resistant to isoniazide; in patients with secondary resistance strains with combined resistance to two or more drugs predominated, however in all instances a combination of isoniazide with other antituberculotics was involved. With regard to the changing epidemiological situation as regards tuberculosis (in particular the arrested decline of the incidence of bacillary tuberculosis and the increase of drug resistance of M. tuberculosis), the authors recommend further monitoring and epidemiological analysis of the incidence of strains with initial and secondary resistance, systematic external checks of laboratory technique used for testing the sensitivity to antituberculotics and its centralization as well as the introduction of analyses of restrictive fragments of the DNA genome (RFLP method) to monitor the spread of tuberculous mycobacteria in the population.

[External control of drug sensitivity determination in mycobacteriologic laboratories in the Czech Republic]

In 1992 and 1993 an external control of sensitivity assessment of coded strains of M. tuberculosis to five basic antituberculotics was made: isoniazide, streptomycin, pyrazinamide, ethambutol and rifampicin. In 1992 from 11 participating laboratories an erroneous result was recorded in 9 (3 laboratories made two mistakes, 6 laboratories one mistake), two laboratories did not provide complete results. Unsatisfactory results were obtained during external controls in 1993. Of 15 participating laboratories four laboratories made one mistake, two laboratories two mistakes, four laboratories three mistakes. Five laboratories (i.e. one third) made more than three mistakes. Analysis of the results revealed a low reproductibility of results of drug sensitivity tests. To eliminate these shortcomings it will be necessary to make systematic external controls with subsequent solution of the shortcomings, restriction of the number of laboratories making these examinations to those who will systematically produce correct results. And it will be also necessary to test the sensitivity tests to antituberculotics in resistant strains in the National reference laboratory for mycobacteria.

Genetic DNA probes for Mycobacterium avium complex identification

The acridinium ester labelled DNA probe specific for M. avium complex (MAC) was used for testing 30 strains of MAC previously identified by conventional procedures. The hybridization was positive in 26 strains, negative in 3 strains and one strain seemed to be contaminated when subcultured. The specific DNA probes allow to identify even the slow growing mycobacterial strains, in positive samples, within two hours while conventional methods usually take several weeks to show the result. A rapid confirmation of a mycobacterial species is invaluable for selecting an effective treatment as early as possible, which is extremely important e.g. in immunosuppressed patients, children with lymphadenitis, etc. Nevertheless, this method has the disadvantage of being too expensive for some laboratories, though questionable if repeated subcultures, technician's time and the delay in obtaining results are taken into account, and enabling to identify only a limited number of clinically significant mycobacterial species using commercially available probes.

Water-borne household infections due to Mycobacterium xenopi

Of 21 M. xenopi excretors recorded in Prague in 1990, 13 suffered from a serious pulmonary disease and the organisms were detected repeatedly in all of them. In 11 flats of these excretors water samples were collected from faucets and showers and M. xenopi was detected in five of them, as well as in five neighbouring flats. In flats of six remaining excretors and 12 adjoining flats, M. xenopi was not found. However, in 14 of 28 examined flats, the clinically insignificant M. gordonae was isolated. Water samples from three water-works, six regional water reservoirs and 10 street hydrants did not harbour mycobacteria. In the authors' view M. xenopi originating from infected drinking water outlets may cause infections in exposed household dwellers.

Application of gas chromatography-mass spectrometry for rapid detection of Mycobacterium xenopi in drinking water

Gas chromatography-mass spectrometry (GC-MS) was used to detect 2-docosanol, a secondary alcohol characteristic of Mycobacterium xenopi, in 7 of 10 analyzed drinking water samples culture positive for that species. GC-MS was also used to detect tuberculostearic acid. Both of these chemical markers were analyzed as halogenated derivatives in the negative-ion-chemical-ionization mode. The numbers of CFU of M. xenopi were lowest in the three GC-MS-negative samples. The described GC-MS method is useful for the rapid detection of M. xenopi in drinking water.

[Detection of mycobacteria in pathologic material using the radiometric method]

For concurrent detection of mycobacteria by the radiometric method BACTEC and the standard cultivation technique 96 samples of pathological material from patients hospitalized with suspected or confirmed tuberculosis was used. The total number of positive samples was 30, using the BACTEC method only, four samples and using the cultivation method only, 10 samples. The assessed difference was not statistically significant. The mean period of positivity with the BACTEC method was 20.4 days, in cultivations 28.8 days. The higher yield of the cultivation method could be caused by various factors. For the BACTEC system inocula of 0.5 ml were used and one cultivation bottle, for the cultivation inocula 1.0 ml and four test tubes for one sample were used. From five samples, positive only on cultivation, only sporadic colonies were obtained after 42-63 days cultivation and in all instances only on one of four media.

Gene manipulation in mycobacteria

Gene manipulation in mycobacteria developed in two phases. In the first phase genes of mycobacteria were transferred into cells of E. coli and Streptomyces lividans. In the second phase, heterologous genes were transferred into mycobacteria either with a shuttle plasmid or hybrid plasmids. A prerequisite for successful gene manipulation in mycobacteria was a thorough understanding of plasmids in mycobacteria. Construction of recombinant DNA molecules contributed not only to the fact that mycobacteria did not remain outside the mainstream of modern genetic research but also to their present practical importance.

[The effect of glutaraldehyde on mycobacteria and on selected types of bacteria]

The author tested the action of 2% alkalinized glutaraldehyde on Mycobacterium tuberculosis, M. kansasii, M. avium, M. xenopi and M. fortuitum, as well as Staphyloccocus aureus, Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris, Bacillus cereus, B. megatherium and B. subtilis. After 5-minute exposure devitalization of M. tuberculosis, M. kansasii and vegetative forms of the tested bacteria occurred. A sporicide effect was recorded already after 30 minutes or after more than 120 minutes. Most resistant were potentially pathogenic M. fortuitum, M. xenopi and M. avium where the disinfectant effect (a drop of CFU by 99.99%) was recorded after 7-63 minutes and their complete devitalization occurred after 3 (M. fortuitum) to 20 hours' (M. avium) action. The author recommends therefore exposure for 24 hours for sterilization of objects contamined with the above species of mycobacteria. This pertains in particular to instruments which cannot be sterilized by heat (endoscopes, bronchoscopes, sigmoidoscopes etc.), used in the diagnosis of mycobacterioses in patients with compromised immunity, e.g. in AIDS.

Mycobacterium xenopi: identification of different chemotypes based on the lipid pattern analysis by TLC

Mycobacterium xenopi, considered as a homogenous species when identified by conventional phenetic markers (Runyon et al. 1974), was subdivided into three distinct chemotypes described here.

Isolation and identification of a morpholine-degrading bacterium

A gram-positive, slowly growing rod effectively utilizing morpholine as the sole source of organic carbon, nitrogen, and energy was isolated from a mixed culture in a laboratory reactor. The strain was tentatively identified as Mycobacterium aurum. Its growth characteristics at 20 degrees C and pH 6.5 were as follows: maximum specific growth rate, 0.052 h-1; half-velocity constant, 1.3 mg/liter; and yield, 0.37 g/g. The optimum temperature and pH were 31 degrees C and 6.0, respectively.

Mycobacteria in the light of modern genetics development

It is generally assumed that genetic research of mycobacteria is delayed as compared with other, more commonly used, bacterial models, particularly in the field of genetic transfers. In the field of mutagenesis the problems have been studied to such an extent that replication maps of the chromosome of M. phlei and M. tuberculosis H37 Rv have already been constructed and a new model of the cell cycle of bacteria exhibiting a slow growth rate has been worked out. When the problems of mycobacterial genetics are looked upon in the light of gene manipulations it may be concluded that mycobacteria belong to a few models whose genes are used for cloning and that problems of practical significance will be studied by means of the most modern approaches.

Agreement and disagreement between laboratories in species identification of mycobacteria

Twenty coded strains of the following species: Mycobacterium avium, M. fortuitum, M. gordonae, M. chelonei, M. intracellulare, M. kansasii, M. nonchromogenicum, M. scrofulaceum, M. terrae, M. triviale and M. xenopi, were subjected to identification in a co-operative study undertaken by seven laboratories of four countries (CSSR, GDR, PRP and USSR). Three of these laboratories recognized 18-19 (90-95%) of the strains, three others 15-17 (75-85%) and one laboratory recognized 8 (40%) strains. In the correctly identified species, agreement between the tests used by all participants was evaluated. The highest rates of agreement in positive or negative results (04-100%) were obtained for nitrate reduction, detection of arylsulphatase, urease and nicotinamidase in M. kansasii, M. avium-intracellulare and M. fortuitum.

Fluorescent method for testing the enzymic activity of mycobacteria

The possibility of utilizing derivatives of 4-methylumbelliferone (4-MUBF) for the determination of activity of enzymes from the group of hydrolyses was tested in 20 strains of 12 species of mycobacteria. The method proved to be suitable especially for determination of arylsulphatase, beta-D-galactose and acid phosphatase.

Cytochemical and biological properties of Mycobacterium bovis BCG

It was the aim of the present communication to find a simple test for a reliable discrimination of Mycobacterium bovis BCG from Mycobacterium tuberculosis. A total of 26 BCG strains, out of them 10 Czechoslovak strains (2 lyophilized cultures of BCG of different batch, 6 strains isolated from abscesses of children after BCG-vaccination and 2 strains from fatal cases after BCG-vaccination) and 16 strains obtained from foreign laboratories, were used. Of the tested characteristics a combination of 3 tests, sensitivity to 1 microgram of 2-thiophene carbonylhydrazide (TCH), activity of 3 acylamidases (urease, nicotinamidase and pyrazinamidase) and a quantitative nitrate test, was found to be most advantageous. The Czechoslovak strains of Mycobacterium bovis BCG were fully sensitive to TCH, of the 3 acylamidases mentioned above only urease was positive and nitrate was reduced only little or not at all. On the other hand, strains of Mycobacterium tuberculosis were always resistant to TCH, had positive urease, nicotinamidase and pyrazinamidase and reduced nitrate very intensively.