Acta microbiologica Hungarica最新文献

Of 182 wild-type human, aerobactin producer Escherichia coli strains 86.3% were insensitive to cloacin. All randomly chosen 51 strains were relatively cloacin tolerant. Cloacin tolerant strains were not considerably more sensitive to hydrophobic drugs than the cloacin sensitive descendant strains. Pathogenicity of the cloacin sensitive strains was significantly lower (p less than 0.05) in intraperitoneal mice infection than that of the cloacin tolerant ones. Suggesting a new aspect of the uptake mechanism of colicins, cloacin tolerance was very frequently associated with an aspecific insensitivity to a broad spectrum of colicins.

The sequential changes of some morphometric parameters (lymph node weight, high endothelial venule (HEV)-content) after an antigenic challenge (sheep red blood cell; SRBC) and the alterations of HEV-function (HEV-adhesiveness measured with a HEV binding assay) were studied in rat lymph nodes over a period of seven days with daily measurements. Authors suggest that the proper estimation of the HEV-content of a lymph node in a HEV binding assay allows to express the HEV-adhesiveness numerically, and to compare the data obtained by this assay quantitatively. The HEV-adhesiveness is the strongest on day 6 after the antigenic challenge, the early increase in weight on day 2 is attributed to an increased blood flow and the changes in the HEV-content are presumed to reflect a simple dilation of HEVs (on day 2) and later (on days 4 and 5) an increase in the height of high endothelial (HE) cells. A crucial role is ascribed to the altered HEV-adhesiveness in the increase of lymphocyte migration to the challenged lymph nodes.

The authors have found morphological alterations identical with hyperfiltration glomerular injury in the renal biopsies of 23 out of 100 patients with IgA nephropathy. In 15 of them the lesions were similar to the different stages of segmental glomerular hyalinosis and sclerosis with deposition of IgM and C3. At the time of renal biopsy, the serum creatinine of all except 8 patients was normal (maximally 170 mumol/1), only 13 had hypertension, and all except 2 were proteinuric. During the follow-up period (mean +/- 2Sd = 138 +/- 76 months) all of them became hypertensive. In 10 patients end-stage renal failure developed, and in another 10, serum creatinine also became elevated (range 124 - 504 mumol/1). On the basis of these data the development of focal segmental hyalinosis and sclerosis should be interpreted as a bad prognostic sign in IgA nephropathy.

Growth temperature affected both the membrane lipid composition and microsoma (Na+, K+)-ATPase activity of Candida kefyr. Higher growth, temperature (37 degrees C) increased the amount of total lipids, phospholipids and free sterol. Ratios of phosphatidylcholine to phosphatidylethanolamine as well saturated to unsaturated fatty acids increased with a rise in growth temperature. Km of the ATPase isolated from the yeast grown at 27 degrees C was minimum, suggesting that the membranes of C. kefyr grown at optimal growth temperature provide the most suitable environment for the activity of ATPase.

A significant difference was observed in the occurrence of the examined markers (Col+, ColV+, Hly+, Aer+, AbR) and in the plasmid carrier state between strains with and without K1 and K5 antigens. Plasmids of the same size were harboured by serotypes possessing K1 and K5 antigens, e.g. among O1: K1: H- strains plasmids of 60-79 Md, among O1: K1: H7, O18ac: K1: H7, O45: K1: H7 and O83: K1: H- strains plasmids of 80-95 Md were frequent. The average plasmid number was higher in K1 strains than in K5 strains. In serogroup O1 the frequency of the plasmid carrier state was associated with the O serogroup and not with the K antigen. The plasmid number in K5 of serogroups O6 and O18 was lower than in K5- strains. Plasmids of 80-95 Md were predominant among the strains derived from blood and cerebrospinal fluid, whereas these plasmids were rare among the K1 and K5 strains isolated from other sources. Plasmids of 60-79 Md were frequent among strains derived from different sources. The 30-40 Md plasmids were relatively frequent among strains isolated from urine. In contrast with literary data, O1: K1: H-, O1: K1: H7 and other frequent serotypes consisted of different clones. Different clones were found within a single serotype, too.

Virological investigations were performed to approach the mechanism of male infertility and recurrent abortions. Infectious adenovirus or herpes simplex virus was found in nearly 40% of semen samples obtained from sterile men. The viruses were detected in latent form in 60% of the cells. The same viruses as in the father's cells were found in the aborted material. In vitro inoculation of cell cultures with material of semen origin made the presence of other latent viruses probable. The affinity of adeno- and herpesviruses to urogenital organs was supported by animal experiments in which a new method of in vivo intratesticular inoculation was applied. The close interaction between urogenital cells and viruses was also supported by in vitro infection of human semen with adeno- or herpesviruses. The viruses absorbed to cells, penetrated the latter and their components replicated inside. It is suggested that local chronic viral infection may play part in male infertility and some cases of the recurrent abortions through damaging of cells. In patients treated with Zovirax, virus carriership ceased and the normal function of sperms started again.

The phagocytic and killing functions of polymorphonuclear cells (PMNs) and monocytes in patients with culturally and serologically proven Chlamydia trachomatis urogenital infections, and the distribution of peripheral blood T cell subsets in the same patients were analysed. A significant impairment of PMNs function was observed in infected patients as compared to the control group, whereas the monocyte function was not affected. In addition, a decrease of CD4+ cells frequency was observed in these patients. Since the PMNs are the most prominent cells observed at the site of C. trachomatis infection, we suggest that a defect of PMNs function may play a role in the host susceptibility to C. trachomatis.

An experimental technology for the production of live freeze-dried vaccines prepared from attenuated Shigella flexneri 2a and Shigella sonnei I strains was developed. It is based on the cultivation of bacterial strains in a fermentor under conditions which ensure high yields. The strains grow in S-form, their antigenic structure is preserved and they remain non-virulent. The attenuating markers are stable. The freeze-dried vaccines retain good immunogenicity when applied intra-intestinally to rats.

A total of 1510 strains from 15 genera of Gram-negative and Gram-positive bacteria were studied. More than 94% of 327 Escherichia coli strains showed beta-D-glucuronidase (BDG) activity. Seventeen serotypes from 170 E. coli O serogroup representatives were negative. Relationship between the existence of BDG positive and negative E. coli strains in the same serogroup or serotype has not been observed. The rate of BDG positivity was 42% among Salmonella arizonae strains and 42.2% among Shigella strains. Only one Citrobacter strain out of the 971 strains belonging to Citrobacter, Edwardsiella, Enterobacter, Hafnia, Klebsiella, Proteus, Serratia, Yersinia, Pseudomonas, Aeromonas, Vibrio and Listeria was BDG positive. A screening method based on only BDG activity is not sufficient for the primary diagnosis of E. coli.