Acta pathologica, microbiologica, et immunologica Scandinavica. Section B, Microbiology最新文献

A total of 85 human sera (32 from patients with carcinoma of the uterine cervix, 32 from matched controls, and 21 from patients with recurrent genital herpes) were tested in two different ELISAs for detection of HSV type-specific antibodies. The prevalence of HSV type 2 specific antibodies in the three groups were 69, 37 and 71% respectively. The prevalence of HSV type 1 specific antibodies in the three groups were 88, 75 and 76% respectively. Analysis of IgG and total antibodies gave identical results.

The production and the persistence of competence factor (CF) and competence factor inactivator (CFI) of four different strains of Streptococcus sanguis in three media (Todd Hewitt broth, medium II and medium IV) have been examined with respect to kinetics. Both the medium used and the strains examined offered implications on the activities of CF and CFI. CF was not detectable in the culture filtrates of strains Wicky (NCTC 9124) and 445. Strain Blackburn (NCTC 10231) showed activity only in Todd Hewitt broth and strain 14567 in Todd Hewitt broth and medium IV. The activity persisted for 2 to 7 hours during exponential growth. In culture filtrates of the strains Wicky and Blackburn the three media yielded high CFI activity persisting during the entire growth period. The strains 445 and 14567 were less potent CFI producers in medium II and medium IV, and no CFI was detected in the culture filtrates from Todd Hewitt broth. Medium II was the most suitable medium for CFI production and seems appropriate for further studies and isolation of the factor. In medium IV no strain had CF activity. This medium was supplemented with serum, albumin, tyrosine or glutamic acid, and CF and CFI production and persistence by strain 14567 were studied in relation to growth phases. CF and CFI activities were observed in the different supplemented media during short periods of growth, but could not be related to any given phase of growth. The presence of CFI in a culture eliminated or reduced the CF activity, and a specific interaction of CF and CFI was observed. The CFI from the strain Wicky inactivated CF from the strains Challis (NCTC 7868) and Blackburn, but not from the strains 13b and 14567. The CFI from the strains 445 and 14567 reduced the activity of CF produced by the strains 13b and 14567, but not CF from the strains Challis and Blackburn.

nucleatum lipopolysaccharides (LPS) of chemotype V were examined for cross-reactivity by indirect haemagglutination in non-absorbed and absorbed antisera. At least three O-antigenic specificities were detected in LPS of five strains. There was a slight cross-reactivity between the LPS of chemotype V and those of chemotype II.

Transfer of five plasmids was studied in 30 different mating systems, involving streptococci of groups A, D and H. The erythromycin resistance marker (Emr) of all five plasmids was transferable at frequencies ranging from 8 X 10(-7) to 2 X 10(-4). All original donor strains except SM60 (pERL1) contained phage activity, but evidence was obtained favouring conjugation over transduction as the mechanism of transfer. The process was rec-independent. The transconjugants were able to serve as donors of the Emr-marker in secondary matings. A shortened derivate (pSM10) of the plasmid pSM10419 could also be transferred. Finally, the presence of the plasmid pSM15346 influenced the expression of the capacity to adhere to human epithelial cells and the resistance to UV-light of the host, whereas anti-phagocytic activity and production NADse and of opacity factor was unaffected by the plasmid.

An improved method for preparing Limulus amoebocyte lysate (LAL) is described and compared with two other well-known procedures. In five Limuli, three different bleeding procedures and three different cell rupture methods were studied. Increased sensitivity of LAL was accomplished by avoidance of the anticoagulant N-ethylmaleimid (NEM) in the bleeding procedure, optimal methods for mechanical cell rupture and use of pyrogen free conditions. Reaction of LAL with as little as 10(-15) gram Lipopolysaccharide (LPS) per ml was generally obtained. To evaluate a possible explanation for the differences in reactivity of LAL between different Limuli, found in one experiment, six Limuli were bled, and the pH and the concentration of protein, Ca2+, Mg2+, Cu2+, Na+ and K+ were determined in LAL and cell-free hemolymph. Inter and intra batch variations were found in LAL, but there was no correlation between the sensitivity of LAL and the content of the above mentioned constituents in LAL and cell-free hemolymph. Experiments with use of NEM in the bleeding procedure and addition of NEM to homogenized cells in different concentrations, showed that NEM inhibits the reactivity of LAL to LPS. It is concluded that the modified method of producing LAL by bleeding without NEM and by using optimal methods for mechanical cell rupture is quick, simple and produces a very sensitive reagent for the Limulus test.

The beta-lactamase activity with ampicillin (A) and cephalothin (Ce) as substrate was examined in 22 E. coli strains by a micro-iodometric - (MIA) and an ultraviolet assay (UVA). The strains were divided into three groups according to their sensitivity to A and carbenicillin (Ca). Group 1 contained 6 A-Ca sensitive (A-s/Ca-s) strains, group 2 contained 8 A-resistant (A-r)/Ca-s strains and group 3 eight A-r/Ca-r ones. MIA with A as substrate showed high activity in group 3. The activities in groups 1 and 2 did not differ and were very low. Group 1 had the lowest and group 3 the highest IC50 with A. UVA with Ce as substrate showed high activity in group 2, lower in group 3 and lowest in group 1. IC50 corresponded to this order. MIA with Ce as substrate showed high activity (measured 25 min after enzyme was added) in group 3, lower activity in group 2 and lowest in group 1. The initial velocity was highest in group 2, but decreased with time. In group 3 the velocity increased with time. Group 2 (A-r/Ca-s) strains contained cephalothinases that apparently were inhibited by iodine. The beta-lactam resistance was probably chromosomally mediated. Group 3 (A-r/Ca-r) strains contained beta-lactamases with predominantly ampicillinase activity and were not inhibited by iodine. The A-resistance was probably plasmid mediated.

The erythromycin-resistance marker of two plasmids, pSM19035 and pERL1, could be transferred by conjugation in matings within group A streptococci and between group H and group A streptococci, with a frequency of 10(-5) to 8 X 10(-7). Two of the recipient strains used, 22v-1 and 22v-2, showed traces of opacity factor (OF) activity. This activity increased markedly upon transfer of both plasmids to the strains, whereas a number of other recipients, viz. 22h-21, 12Teiko-1 and Challis 6-1, remained OF-negative after conjugation. Furthermore, the transconjugants resulting from matings using strains 22v-1 and 22v-2 as recipients expressed anti-phagocytic activity. Attempts were made to type the transconjugants but they did not belong to type M12, M22 (the types from which the parents were derived) M3 or M1. Concomitant with the expression of anti-phagocytic activity, IgG and IgA Fc-receptor activity occurred in the transconjugants of 22v-1 and 22v-2, whereas the donor and recipient cells were without receptors. It was not possible to demonstrate extrachromosomal DNA in transconjugants possessing anti-phagocytic, OF or Fc-receptor activity, although they retained their ability to serve as donors of the Emr marker. It is suggested that the triggering by plasmids of anti-phagocytic activity, OF and IgG and IgA Fc-receptors is due to insertion of plasmid DNA into the chromosome.

Sheep erythrocytes opsonized with IgG or C3b were frozen in various cryoprotective agents, thawed, and compared to corresponding unfrozen erythrocytes exposed to the cryoprotectants and to unfrozen erythrocytes not exposed to the cryoprotectants (controls) as test particles in macrophage attachment and phagocytosis assays. Fc-receptor-mediated attachment and phagocytosis were not influenced by the use of any cryoprotective agent tested or by freezing the erythrocytes. This was also the case with C3b-receptor-mediated attachment. Phagocytosis via this receptor was negligible in normal macrophages, but tended to be slightly more effective when the test particles had been treated with cryoprotective agents. In vitro stimulation of the macrophages with Escherichia coli endotoxin, however, triggered the capacity to internalize treated and untreated erythrocytes equally.

The invasive potential of 45 presumptive enteropathogenic and non-enteropathogenic bacterial strains belonging to the family Enterobacteriaceae have been tested using the Serény test and HEp-2 cell monolayers examined by a combined light optical method. All the presumptive enteropathogenic strains of Shigella dysenteriae, S. boydii, S. flexneri, S. sonnei and Salmonella typhimurium showed in vitro invasiveness in the HEp-2 cell culture test. Fourteen presumptive non-enteropathogenic strains of Escherichia coli showed no invasiveness in either of the two test systems. Two strains of S. flexneri and all the 6 strains of S. typhimurium gave a negative result in the Serény test although they were invasive in HEp-2 cell cultures. Otherwise there were correlative results between the cell monolayer test and the Serény test. In the cell monolayer test the different species of enteropathogenic bacteria showed considerable variation in invasive potential.

The purpose of this study was to investigate the efficacy of long-term penicillin-gentamicin treatment on experimental S. faecalis endocarditis due to selected strains; one strain was homogeneously resistant to 8000 micrograms/ml streptomycin (IC50 and MIC greater than 8000 micrograms ml), the other strain heterogeneously resistant to 8000 micrograms/ml streptomycin (IC50: 3300 micrograms/ml, MIC: greater than 8000 micrograms/ml. Both strains showed low-grade resistance to gentamicin (MIC 10.5 and 25 micrograms/ml, respectively). The results showed that there was significant effect of the treatment in rabbits with endocarditis due to both strains, as measured by lowered mortality and by high bacteriologic cure rate. Despite effective antibiotic treatment, a high incidence (57%) of congestive heart failure was noted in rabbits late in the treatment period or after termination of antibiotic treatment, probably due to healing processes on the aortic valves. In human cases of S. faecalis endocarditis the antibiotic treatment should be either penicillin plus streptomycin or penicillin plus gentamicin. However, in cases where the infecting strain is homogeneously resistant to 8000 micrograms/ml streptomycin, the treatment with penicillin plus gentamicin is clearly the drug combination of choice.