Bacteriocin-like activity of Bacteroides fragilis group isolated from marmosets.

The ability of strains of the B. fragilis group, isolated from the oral cavity and intestine of marmosets, to produce bacteriorin-like substances in solid medium, in terms of auto-, iso- and heteroantagonism, was evaluated. Antagonistic activity was exhibited by 52% of the intestinal strains, 3 of which showed autoantagonistic activity. Three out of 9 oral strains isolated, tested against themselves, showed simultaneous isoantagonism to 4 indicator strains; but not autoantagonism. The same 9 oral strains, when tested against 16 reference strains, revealed interspecific activity only against 2 Gram-positive microorganisms. Higher activity, evaluated by the size of the inhibition halo, was observed in BHI-S agar, and greatest inhibition was obtained after 72 h of incubation.

Extraction, partial purification and characterization of a bacteriocin (fragicilin) produced by a strain of Bacteroides fragilis isolated from Callithrix penicillata.

A strain of Bacteroides fragilis, isolated from the marmoset Callithrix penicillata, produced protein(s) with bacteriocin activity (fragicilin). Two active fractions (36 and 150 kDa) were isolated by chromatography. The bacteriocin exhibited iso- and heteroantagonism. It remained stable between pH 3 and 10 and at 60 degrees C for 24 h. Pronase, trypsin, proteinase K and type VII protease inactivated the bacteriocin, giving evidence of its protein nature.

Biochemical analysis of the methylic antigen of Paracoccidioides brasiliensis.

Yeast forms of five strains of Paracoccidioides brasiliensis (SN, 2, 18, 192 and JT-1) were cultured in a synthetic medium for obtaining methylic antigens. These antigens were lyophilized and studied for each strain, to determine their partial biochemical composition, through measurements of total lipid, protein and carbohydrate contents. Lipids of methylic antigens were purified and analysed for sterols, phospholipids, glycolipids, lipoproteins, and partial characterization of sterols. Significant differences were found among antigenic preparations derived from distinct P. brasiliensis strains, in relation to the quantitative determinations. On the other hand, sterol analysis revealed the presence of ergosterol, lanosterol and squalene in all samples. The diversity verified in the biochemical characteristics of antigens derived from different P. brasiliensis strains, confirm the need of using a pool of fungal samples in order to produce antigen preparations for serological procedures without hampering their sensitivity.

Antimicrobial resistance and plasmid detection in strains of the Bacteroides fragilis group.

Resistant populations of the Bacteroides fragilis group bacteria (two reference ones and two isolated from human and Callithrix penicillata marmoset) were obtained by the gradient plate technique, to clindamycin, penicillin G, metronidazole and mercuric chloride. All the four tested strains were originally susceptible to the four antimicrobial drugs at the breakpoint used in this study. MICs determination for the four cultures gave constant values for each antimicrobial, on the several steps by the gradient plate technique. The intestinal human B. fragilis strains showed three DNA bands, that could be representative of only two plasmids in the closed covalently circular (CCC) form with molecular weights of approximately 25 and 2.5 Md. The results do not permit an association between the presence of plasmid in the human strain with the susceptibility to the studied drugs. The four strains were beta-lactamase negative in the two methods used, and no particular chromosomal genetic resistance marker was demonstrated. The resistance (MIC) observed, after contact with penicillin G and mercuric chloride, were two-fold in the four tested strains.

Isolation and identification of strains of Bacteroides fragilis group from the digestive tract of Callithrix penicillata marmosets.

Thirty-five strains of the Bacteroides fragilis group were isolated from oral and intestinal samples from 5 wild caught, captive Callithrix penicillata. Nine oral strains of Bacteroides fragilis (7) and Bacteroides distasonis (2), and 26 intestinal strains of Bacteroides fragilis (14) and Bacteroides distasonis (12) were identified.

Bacteriological evaluation of wounds in seriously burned hospitalized patients.

During the period between May and December 1988, 21 patients were studied bacteriologically at Hospital João XXIII's burn's unit which belongs to "Fundação Hospitalar do Estado de Minas Gerais" in Belo Horizonte, Brazil. A qualitative and quantitative evaluation of aerobic and facultative bacteria from burn wounds was carried out by the standard filter paper disc technique, including antibiotic susceptibility. At the same time an evaluation of those bacteria isolated from the environmental unit was performed. The most common organisms recovered from wounds of patients were: Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis. P. pseudomallei was the most frequent strain recovered from environmental specimens. In nearly all patients specimens (16 in total) from whom P. aeruginosa was isolated, the rate of CFU/cm2 of skin was above 10(2). In nine of these, it reached 10(5), which is equivalent to 10(7) CFU/g of burned tissue.

[Anti-Leptospira agglutinins in different professional groups in the city of Londrina, Paraná]. / Pesquisa de aglutininas antileptospira em diferentes grupos profissionais na cidade de Londrina, Paraná.

Serum samples were obtained from 208 individuals in Londrina, Paraná, Brazil. The serum were analysed for leptospiral agglutinins by agglutination microscopic tests and 28.4% were positive. The highest positivity was found for the serum of garbage collector (46.7%).

Susceptibility of Actinobacillus actinomycetemcomitans strains to norfloxacin.

The minimal inhibitory concentration of norfloxacin to Actinobacillus actinomycetemcomitans strains isolated from patients with localized juvenile periodontitis was determined by using an agar dilution method. All the tested strains, including the three reference strains, were susceptible at concentrations lower than the breakpoint used, with 90% of the strains susceptible to 0.125 micrograms/ml.

[The microhemagglutination reaction for the routine serologic diagnosis of syphilis]. / A reação de microhemaglutinação para sífilis no diagnóstico sorológico de rotina.

The authors present the results of VDRL reactions (qualitative and quantitative) and microhaemagglutination assays (MIPHA) on 305 serum samples. The samples selected among the sera asked for syphilis serology at a clinical laboratory, were those which the results on VDRL reactions were observed to be reactive at low titles, not reactive or inconclusive. From these 305 samples, 87 (28.5 por 100) were also processed by the FTA-Abs test. The reactivity concordance between the tests was compared and the efficiency of the MIPHA as confirmatory diagnostic test was discussed. The conclusions prompt to the usefulness of the MIPHA on syphilis serodiagnosis routine as a function of its sensitivity, specificity, low costs and technical simplicity.

Histopathological alterations induced by non-viable cells and biochemical fractions from Paracoccidioides brasiliensis in mice.

Non-viable cells and biochemical fractions from Paracoccidioides brasiliensis were obtained for experimental inoculation in mice and posterior histopathological analysis. Dead total fungus, total fungus disrupted by sonorous waves, lipids of the fungus, supernatant of the lipid purification, integral and disrupted fungus free of lipids were obtained. The six preparations arose from masses of lyophilized yeasts of a recent isolate of P. brasiliensis (strain JT-1) and from a "Pool" equitably constituted by four strains maintained in laboratory for a long time (SN, 2, 18 and 192). Different doses of the 12 preparations were intraperitoneally inoculated and histopathological analysis were done 30 days later. This analysis showed that all the inoculated preparations gave origin to inflammatory foci, except the one designated "supernatant of lipid purification". The alterations were detected exclusively in the liver of the animals and occurred from the smallest dose tested (1 mg), with exception of the lipids of the fungus, where the foci appeared only from a 3 mg dose onwards. No difference in the capacity of inducing histopathological alterations was found between the preparations obtained from the recent isolate (JT-1) and from the older ones ("Pool"). On the other hand, an increase of the number of inflammatory foci in function of the inoculated dose was observed.

The use of methanol extract of Leptospira interrogans in complement fixation tests for leptospirosis.

Methanol extracts were obtained from L. interrogans serovars icterohaemorrhagiae and canicola and L. biflexa serovar patoc. Human sera from 167 normal individuals and 40 patients with different infectious diseases tested by complement fixation tests showed negative reactions. Sera from 100 patients with a suspicion of leptospirosis were tested by complement fixation tests and microscopic agglutination reactions. Agreement of 84% was found for those two reactions. Positive microscopic agglutination tests at a dilution 1:20-1:400 with negative complement fixation tests were observed in 5% of patients and negative microscopic agglutination with complement fixation tests in the range of 1:20-1:1280 were observed in 11% of the cases.

Haematological alterations induced by biochemical fractions of Paracoccidioides brasiliensis in mice.

Biochemical fractions of Paracoccidioides brasiliensis were obtained for experimental inoculation in mice followed by haematological analysis. Dead total fungus, total fungus disrupted by ultrasonic waves, lipids of the fungus, supernatant of the lipid purification, and integral and disrupted fungus free of lipids were obtained. The six fractions were obtained from lyophilized yeasts of a recent isolate of P. brasiliensis and from a pool comprising equal amounts of four strains maintained in the laboratory for some time. Different doses of the 12 fractions were intraperitoneally inoculated into mice and haematological analysis was done 30 days later. No significant alterations were detected in the red blood cell series. However, the white blood cell series showed marked alterations, such as leukopenia, with relative neutrophilia and lymphopenia. Thrombocytosis occurred widely. The haematological alterations revealed associations with the injected doses without relation to the biochemical composition of the different fractions. No difference in the capacity for inducing haematological alterations was found between the fractions obtained from the recent isolate and from the older ones.

Six years' experience in treatment of chromomycosis with 5-fluorocytosine,.

Twenty-three patients with chromomycosis were treated with oral 5-fluorocytosine for periods ranging from 2 to 67 months. Sixteen were considered cured, after 3 consecutive monthly controls showing healing of the lesions and absence of fungi in mycologic and histopathologic examinations of biopsy specimens. Seven, in spite of initial clinical improvement, showed resistance to treatment. Associated treatment with amphotericin B, calciferol or thiabendazole failed to help patients resistant to 5-fluorocytosine. Resistance seems to occur especially in those with long-standing lesions or widespread involvement.

Distribution of Campylobacter pylori and gastritis in the stomach of patients with and without duodenal ulcer.

The presence of Campylobacter pylori and histological changes of gastric mucosa were studied in 50 consecutive patients with gastric complaints. C. pylori was isolated from the antrum, body, and fundus of 40 patients with (n = 20) and without (n = 20) duodenal ulcer. The incidence of gastritis was not significantly different in the antrum of C. pylori-positive patients with and without ulcer. Otherwise, oxyntic mucosa of both body and fundus regions exhibited gastritis in 64.1% of the C. pylori-positive non-ulcer patients, whereas those with duodenal ulcer presented oxyntic mucosa that was histologically normal or near normal.

[Infection control procedures used in dental offices in Belo Horizonte]. / Procedimentos utilizados no controle de infecção em consultórios odontológicos de Belo Horizonte.

Survey data from 300 randomly selected private dental practitioners working in Belo Horizonte, Minas Gerais, were used to evaluate the infection control procedures routinely practiced here. The function of this report might be to alert the teaching team from Dental Schools and the dentists to the problems that potentially contribute to the transmission of infectious disease as a first step for additional specific recommendations to an effective and safe infection controL program that we intend to discuss later.

Purification and partial characterization of a bacteriocin isolated from Bacteroides ovatus H47.

A new intracellular bacteriocin isolated from a human fecal strain of Bacteroides ovatus was partially purified through ammonium sulfate precipitation, ion exchange chromatography, gel filtration, and preparative polyacrylamide gel electrophoresis (PAGE). The bacteriocin is stable at a pH range of 3-10, at 60 degrees C for 24 h, and at -70 degrees C for 6 months. It is inactivated by proteolytic enzymes. The molecular weight, estimated by sodium dodecyl sulfate--PAGE, is 78 kDa. Fifty strains of the Bacteroides fragilis group were isolated from fecal samples, and 41 of the isolates were shown to produce an antagonistic substance against at least 1 indicator strain. Iso-, auto-, and hetero-antagonisms were observed.