In four strains of Clostridium difficile the formation of capsules was demonstrated by light and electron microscopy.
Pathogenicity testing of 10-day-old fertilized hen's eggs infected with Listeria species demonstrated that L. monocytogenes isolated from cheese and human samples caused death in 100% of the injected chicken embryos within 96 h. In contrast, L. innocua isolated from cheese was fatal for only 17% of the infected embryos. All embryos infected with L. seeligeri survived. The results confirmed statements of previous authors about the pathogenicity of L. monocytogenes, regardless of its origin.
In 1986, 1711 nymphal and adult Ixodes ricinus orginating from Berlin (West) forests were examined individually or in pools of up to 10 ticks for the presence of Borrelia burgdorferi, the etiologic agent of Lyme borreliosis. Detection of borreliae was carried out by means of a culture method using modified Barbour-Stoenner-Kelly-Medium (BSK II). Tick populations from 14 out of 15 locations contained positive specimens. The calculated minimal infection rate of pooled ticks was 2.5% in nymphs (n = 1365), 10.2% in females (n = 59), and 5.3% in males (n = 114). Among those ticks examined individually, none of the nymphs (n = 49) proved to be positive but B. burgdorferi was isolated from 8.2% of the females (n = 73) and 7.8% of the males (n = 51). Fifty-five out of 56 isolates were identified as B. burgdorferi by means of an indirect immunofluorescence test (IFT) using monoclonal antibody H 5332. From these results B. burgdorferi must be considered as being present in the Berlin area.
In the course of studies on the biology of hepadnavirus infections, duck hepatitis B virus (DHBV) DNA was isolated from the serum of a German Pekin duck. Viral DNA was cloned in E. coli using pBR 322 DNA as a vector. The cloned DHBV DNA F 1\2 was characterised by restriction enzyme analyses.
By means of the cell fusion technique, two hybridoma cell lines, V-1 and H2-1 have been obtained. V-1 cells secrete monocloncal antibody against serovars icterohaemorrhagiae and dakota. The H2-1 cell line secretes serovar-specific monoclonal antibody against serovar H2.
A total of 174 sera from healthy Polish individuals of different age groups were tested for TSST-1 antibody by the micro-ELISA method. Over 90% of sera contained the antibody with titres equal to above 1:102, even in children and adolescents. The data suggest that the majority of the Polish population acquires TSST-1-antibody during early childhood, whereas a small portion of the population seems to remain anti-TSST-1-negative.
A spontaneous rough (Rg) mutant of M. avium ATCC 15769 was mutagenized using N-methyl-N-nitro-nitrosoguanidine (MNNG). Out of 54 clones initially chosen on the basis of their morphological appearance on the 7H11 agar, seven Rg clones were selected on the basis of their response to current biochemical tests, and were later characterized for their cell wall amphiphilic contents (analysis of loosely-bound surface lipids for mycosides, peptidolipids, phospholipids, and mycolic acids by thin layer chromatography, and fatty acids by gas chromatography), and ability to grow intracellularly inside J-774 macrophages. A parallel study was also performed on a previously reported Rg mutant of M. intracellulare serovar 20 (W. W. Barrow and P. J. Brennan, J. Bact. 150 (1982) 381–384) which lacked the ability to synthesize mycosides C (MYC−). The results obtained were compared to parental smooth (Sm) colony-types of the respective M. avium-intracellulare strains. Our results showed that neither the ninhydrin-reacting lipids (probably peptidolipids) nor the glycopeptidolipids (mycosides C) were primary factors responsible for the intracellular survival and multiplication of these bacteria. Ultrastructural studies showed that although the polysaccharide-rich outer wall layer (POL) in case of MYC− Rg strain was not uniformly distributed and contained blebs, these bacteria formed the characteristic electron-transparent zone (ETZ) upon phagocytosis by macrophages. Furthermore, the multiplication of MYC− Rg strain inside macrophages did not result in intracellular selection of MYC+ bacteria, nor in Rg to Sm transition.
In the present study, the binding of human neutrophils to Toxocara canis larvae was examined in vitro. It was found that IgG and/or the C3 component of complement were able to enhance the attachment of the cells to the parasites. This was associated with the generation of strong chemiluminescence reactions.
Antigens from Vibrio cholerae O1 were analyzed by crossed immunoelectrophoresis (CIE) using sera from immunized rabbits. Thirty different anode-migrating antigens were detected in sonicated antigen preparations of V. cholerae. These antigens were numbered in order to establish a reference precipitation pattern. Antigen no. 30 was identified as the lipopolysaccharide (LPS) antigen, because it reacted with (i) periodic acid-Schiff (PAS) reagent and (ii) the affinity-purified anti-LPS antibodies. Treatment with proteinase K demonstrated that most of the precipitation lines were due to proteins, a part of which were localised at the cell surface. The major outer membrane protein was found to be closely associated with the precipitation line due to the LPS (antigen no. 30). The antigenicity and immunogenicity of V. cholerae cells killed by different methods (merthiolate, heat, phenol, formalin) were examined. As determined by CIE, killing with merthiolate preserved most of the major components of V. cholerae. Heat, phenol and formalin altered the antigenic mosaic of V. cholerae. These results suggested that CIE can be used to analyze several aspects of V. cholerae antigens.
L3 larvae of Anisakis simplex, isolated from freshly caught herrings were cultured in Medium 199 at different temperatures to obtain excretory-secretory (ES) antigen. Larvae have been cultured in vitro for a period of 11 months. A crude extract of A. simplex larvae was compared with ES antigen obtained under 4 different culture conditions for the determination of IgG and IgE antibodies by ELISA and a modified RAST, respectively. 1 serum from a patient with histopathologically proved anisakiasis and 4 samples from persons with presumptive clinical disease were positive in the ELISA. Two sera were positive in the RAST. A combination of both tests is suggested for the serodiagnosis of human anisakiasis.
Pasteurella haemolytica-cultures, isolated from cattle with respiratory diseases, were investigated for their biotype, serotype, antimicrobial resistance and plasmid content. A plasmid encoding a beta-lactamase could be demonstrated in 9 of 19 Pasteurella haemolytica-cultures. These 9 cultures, all belonging to biotype A and serotype 1, were resistant to ampicillin, carbenicillin, penicillin G and ticarcillin. The plasmid of the respective cultures proved to be identical upon Southern blot hybridization. It could be transformed into Escherichia coli 490 A where it expressed again a beta-lactamase-activity.
The evidence showing that non-opsonic recognition of bacteria by phagocytes involve interaction between bacterial surface lectin and sugars on the phagocytic cells is summarized. This process, termed lectinophagocytosis, probably occur in vivo as evident from experimental infections with mixed phenotypes one of which express mannose specific (MS) lectin which mediate lectinophagocytosis of the bacteria and the other does not. In all cases studied, the lectin bearing phenotype survived better in phagocytes-poor sites and the phenotype which does not express this lectin survived better in phagocytes-rich sites. Due to the phase variation phenomenon, an off-on switch allowing the bacterial clone to alternate between lectin expressing and non-expressing phenotypes, the invading bacteria grow as a mixture of phenotypes. The phenotype expressing fimbrial lectin for which receptors are accessible on phagocytic cells undergo lectinophagocytosis. The phenotypes not expressing fimbrial lectin or expressing lectin for which receptors are not available on phagocytic cells may escape phagocytosis and proliferate. It is postulated that pathogenesis of inflammation and tissue damage following infections with MS lectin bearing bacteria may be partly due to both bacterial proliferation resulting in the release of toxic products and to lectinophagocytosis associated with the release of inflammatory agents.
Rapid methods serving the detection of intestinal Bacteroides species in clinical specimens are of great significance. For this purpose, an identification of the species is possible at present only by means of immunofluorescence (IF). Using preparations of antigens of different intestinal Bacteroides species (B. fragilis, B. thetaiotaomicron, B. uniformis, B. ovatus, and B. distasonis) as well as immune sera prepared against them, the presented results have shown the possibility of specific identification of the species involved by means of direct and indirect IF, respectively. However, it could be demonstrated that the direct IF results in a more brillant appearance of the bacteria than the indirect procedure. Convincing results could be obtained also in the investigation of clinical specimens by means of the direct IF using a pool of conjugated immunoglobulin fractions (sensitivity 88%, specificity 100%). Therefore, the direct method to detect intestinal Bacteroides species by IF should be preferred.
Two symptomatic Toxoplasma infections of laboratory personnel have been serologically followed up for 5.5 and 10 months, respectively. Results obtained by commonly used test systems (indirect fluorescent antibody tests for IgG and IgM antibodies, complement fixation test) were compared with those of two recently developed and improved tests for IgM detection (immunosorbent agglutination assay [ISAGA] and solid-phase indirect haemadsorption assay [SPIHA] as well as with those of a test designed for the detection of circulating antigen (cag-ELISA).
The interaction of opsonized E. coli K-12 bacteria and polymorphonuclear leukocytes (PMN) was quantified, using luminol-enhanced chemiluminescence (CL) as a parameter of PMN stimulation. On a double-logarithmic scale light emission depended on the opsonin concentration used during pre-opsonisation. The most potent CL-inducing agent was fresh human serum, and its stimulatory activity depended on an intact complement (C) system. Both inactivation of C by heating or blocking the classical C pathway with EGTD decreased the CL-inducing potency by a factor of 8 to 16. Hypogammaglobulinemic heated serum mediated little CL. IgG for intravenous use mediated CL generation, but reduction/alkylation and sulphitolysis reduced the stimulatory power. Evidence is presented that the anti-K-12 antibodies within commercial IgG and IgM used for substitution do not improve the stimulatory power of IgG-deficient, IgM- and C-sufficient serum, unless very high Ig concentrations are substituted.
Urogenital specimens from 200 male and female patients were cultivated for the detection of C. trachomatis. For comparison, serum of the same patients was investigated with the Ipazyme IgA and IgG test. This comparison of culture and serological tests revealed a sensitivity of the IgA Ipazyme test of 56% and a specificity of 81%. For the IgG Ipazyme test, the corresponding values were 77% and 39%. The sensitivity of the conventional immunofluorescence test reached 46% and its specificity was 50% for the same group of patients. Antibiotic treatment of 13 IgA-positive patients resulted in a significant decrease of the titre in only one case. The introduction of the Ipazyme test does not open a new aspect in chlamydial serology, i.e. the diagostic value of serology for the detection of a current chlamydial infection remains low.
Duplicate high vaginal swabs were obtained from 200 parturient women at Abeokuta (Nigeria). By culture on a selective agar twenty-two women (11%) were found to harbour group B streptococci. The second swab was subjected to a 45 min enzymatic extraction procedure and then tested in a latex agglutination test for group B streptococcal antigen (Wellcogen Strep B; Wellcome Diagnostics, Dartford, UK). The latex test permitted the detection of three out of 22 colonized women (overall sensitivity 13.6%). The sensitivity for detection of heavy colonization was 50% (three out of six women). It is concluded that the sensitivity of the method employed for rapid detection of group B streptococcal antigen in vaginal swabs is still unsatisfactory.
Among 250 S. aureus clinical isolates, the incidence of TSST-1 production was 18.0%. S. aureus var. hominis strains were predominant (95.6%), producing high levels of toxin in vitro, within the range of 0.6 to 4.3 μg/ml and exhibiting crystal violet binding with C/D pattern. No correlation was found between the level of TSST-1 production in vitro and the clinical course. Two (3.4%) of the var. bovis strains produced toxin in amounts less than 0.6 μg/ml and did not bind crystal violet. None of the 24 var. canis isolates produced TSST-1. Fifty five per cent of the isolates of phage group I produced TSST-1 and corresponded to 57.8% of the toxigenic strains. Two of the 250 patients developed toxic shock syndrome.
