Acta microbiologica Academiae Scientiarum Hungaricae最新文献

Mouse lung toxicity of 439 strains (431 Escherichia coli, 1 Shigella dysenteriae 1, 1 Enterobacter cloacae, 5 Vibrio sp., 1 Klebsiella) was compared to other pathogenicity tests (mouse virulence, enterotoxicity, guinea pig eye test), to serogroup distribution, loss of virulence on storage, origin and haemolytic activity. Mouse lethality was highest in serogroup O4 (p < 0.001), O18a,c (p < 0.001); serogroups O6, O20, O75, O115, O147 were next in order. E. coli serogroups O19, O26, O28a,b, O32, O51, O53, O55, O73, O78, O79, O83, O105, O111, O112, O114, O117, O119, O124, O129, O136, O142 failed to show lung toxicity. Strains O4 and O18 isolated at different periods of time did not differ significantly in the lung test (p = 0.05, p = 0.01, p > 0.1, p = 0.05, p > 0.1). There was no significant difference between strains isolated from the stools of patients with enteritis and of healthy individuals (p = 0.1, p > 0.99) and between those isolated from all faecal specimens and from extraintestinal samples (p = 0.05, p > 0.3). There was no correlation between lung toxicity and other pathogenicity tests. Since strains isolated from healthy individuals were also toxic for mice, a positive lung test cannot be considered a criterion of the aetiological role of the agent.

By Enzyme-Linked Immunosorbent Assay (ELISA) purified cholera and Escherichia coli enterotoxins can be detected as sensitively as by CHO cells. There is a linear relationship between toxin concentrations and extinction values. In plates sensitized with toxins, antitoxins can be titrated with high sensitivity. ELISA cross-titration experiments demonstrate the existing antigenic relationship between cholera toxin and heat labile E. coli enterotoxin. Plates sensitized with either anti-E, coli-IgG or anti-cholera-IgG are suitable for detecting both cholera toxin, and E. coli LT. ELISA seems to be a simple, sensitive and economic method for quantitation of enterotoxins and toxin-specific antibodies.

The haemagglutination patterns of 255 urinary Escherichia coli isolates were examined with human (A, Rh+), bovine, chicken and guinea pig erythrocytes in the presence and absence of D-mannose. The strains were divided into four groups according to their haemagglutination properties. About 40% of the isolated agglutinated human red blood cells in the presence of D-mannose. The haemagglutinin of one of these. E. coli O18a, c: K- strain No. 119 was stable, temperature sensitive, did not develop at 18 degrees C and could be isolated by the methods used for the production of fimbriae. Electron microscopy showed fimbriae on the surface of Strain No. 119. An absorbed serum prepared from a derivative cured of haemagglutinating property (No. 119/1) agglutinated all the strains haemagglutinating human erythrocytes in the presence of mannose, but none of those having other haemagglutination patterns. Serologically, the antigen of No. 119 is independent of the K88, K99, "987" and CF I factors and shows some relationship to CF II.

Eggs deposited by different migrating wild bird species in pond farm areas in Hungary were examined for yolk antibodies to different variants of human A/H3N2 influenza virus. Antibodies to Victoria/75 and Texas/77 occurred in 17.9 and 32.0% of gull eggs, and 5.6 and 16.4% of common tern eggs, respectively, while antibodies to A/H1N1/77 occurred in roughly similar proportions (10.2 and 13.4%) in the eggs of both species. Infection of the gull and tern populations of given areas by human and avian influenza A viruses differed greatly in two consecutive hatching periods. While in 1978 7.6 and 1.1% of the gull and tern eggs, respectively, contained antibodies to the avian subtype Havl, no such antibodies were found in 1977. Subtype A/H3N2/Texas/77 virus was isolated from adult gulls and 1-3 weeks old gull chicks, and subtype H1N1 virus from mallard ducks. Three months before the onset of the Texas/77 epidemic, 95% of SPF chickens, and 71-81% of chickens hatched 3 months after termination of the A/H1N1/77 epidemic, had had HI, VN and SRH antibodies to the Texas/77 strain and A/H1N1/77 strains, respectively.

A motion picture study of macrophage culture infected with the endozoits of Toxoplasma gondii revealed an enhanced locomotor activity in afected cells: regular contractions of the cell resulting in an incomplete extrusion of the parasitophorous vacuole or host-cell destruction, formation of excessive undulating membranes and pinocytotic vesicles.

Mycobacterium and Nocardia species were examined for survival after exposure to chlorhexidine gluconate. In clinical samples M. smegmatis, M. phlei, M. marinum, M. gordonae, M. scrofulaceum, M. kansasii, M. chelonei complex, M. fortuitum, M. flavescens, M. avium, M. xenopi and Nocardia sp. survived pre-treatment with the agent. After exposure of saline suspensions of bacteria to chlorhexidine gluconate, M. smegmatis, M. phlei, M. marinum, M. gordonae, M. pellegrino, N. corallina, N. rubra and Rodochrous gordonae were not recovered, and M. fortuitum and N. asteroides grew poorly.

A DNA-dependent ATPase (molecular weight 71 000) free of nuclease activity has been purified from Bacillus cereus. The enzyme shows similar characteristics as the enzyme isolated from Escherichia coli and Bacillus subtilis. Heat denatured DNA stimulates the rate of ATP hydrolysis to ADP and Pi to an extent about tenfold higher than the native DNA. Double stranded DNA without single stranded regions is not a suitable cofactor for the enzyme. The ATPase is inhibited by adenosine 5'-(beta, gamma-imino)-diphosphate, while another ATP analogue, adenosine 5'-(beta, gamma-methylene)-diphosphate has no effect on ATPase activity. KM for ATP is 0.38 mM, the apparent KM for nucleotide equivalent DNA is 1.2 microM. Evidence of the unwinding function of the enzyme is presented.

Attachment of various bacteria to human, peripheral blood and tonsil lymphocytes was investigated in vitro. About 20% of tonsil lymphocytes bound Staphylococcus epidermidis, whereas the binding of other strains was negligible. The influence on cytoadherence of human serum, immunoglobulins (human IgM, IgG, IgA, as well as their respective anti-Ig's), and carbohydrates (mono and polysaccharides) was measured. It was found that heterogenous surface structures of the lymphocytes participate in the attachment.

By using a beta-lysin-producing test strain and anti-beta + delta lysins, the lysins of Staphylococcus aureus strains can easily be determined. The method was used for examination of the haemolysin production of 300 S. aureus strains isolated from human post mortem material and bovine mastitis. The results were cross-checked with those of three other typing tests, viz. phage typing, crystal-violet activity and lipase production. Strains isolated from human material produced most frequently alpha + delta, and less frequently delta or alpha lysins. The isolates belonged to phage groups I, II, III, were crystal violet negative and produced lipase. The bovine strains produced mostly beta + delta or alpha + beta + delta lysins, less frequently delta or beta lysins. The isolates belonged to phage group IV or were typable with phage 116 of phage group II. The majority of the strains was crystal-violet negative, lipase production was not characteristic.

Stable L-forms were induced from Staphylococcus aureus and Streptococcus faecalis. These formed typical foamy L-colonies and showed large and small round bodies. They grew continuously on routine antibiotic-free nutrient broth and blood agar media for 12 passages without reversion to their parental forms. At different concentrations of penicillin various morphological forms were observed. Effect of sucrose, normal horse serum and penicillin on their adaptation and stabilization is discussed.