Showing papers in "Acta Pathologica Microbiologica Scandinavica Section B Microbiology in 2009"

The establishment of K99, a thermolabile, transmissible escherichia coli K antigen, previously called "Kco", possessed by calf and lamb enteropathogenic strains.

Abstract: The transmissible antigen in enteropathogenic E. coli strains from calf and lamb, previously called Kco, is established as the E. coli K99 antigen. It is probably of protein nature since it is destroyed by heating. It is pointed out that other antigens present, growth medium and unknown factors are of great importance for the demonstration of this antigen.

Rapid diagnosis of Enterobacteriaceae. I. Detection of bacterial glycosidases.

Abstract: The paper describes a number of tests for the rapid detection of glycosidases including alpha-glucosidase, beta-glucosidase, beta-glucuronidase, beta-xylosidase and alpha-fucosidase. The methods use heavy suspensions of viable but non-multiplying bacteria in a buffered solution of a chromogenic substrate. The results of the tests are readable within 4 h. The application of these tests to a collection of 633 strains of Enterobacteriaceae and Vibrionaceae demonstrates that some of the tests may be valuable additions to the present tests available for the identification of bacteria belonging to these families. beta-glucuronidase activity was observed only in strains of the Escherichia-Shigella group. 97 per cent of the Escherichia strains possessed beta-glucuronidase activity. beta-xylosidase activity was almost completely restricted to strains of the Klebsiella-Enterobacter group in addition to Yersinia strains. None of the strains possessed alpha-fucosidase activity.

Deoxyribonucleic acid relatedness among species of slowly-growing mycobacteria.

Abstract: DNA-DNA hybridization is a reliable method for determining the phylogenetic relationship between bacterial strains. The hybridization kinetics for DNA from different slowly-growing mycobacteria were measured optically in a spectrophotometer. The results indicate that M. tuberculosis and M. bovis belong to one species. M. avium and M. intracellulare are two species, but some serotypes, now designated M. intracellulare, actually belong to M. avium.

Balkan (endemic) nephropathy and foodborn ochratoxin a: preliminary results of a survey of foodstuffs

Abstract: Ochratoxin A is a nephrotoxic fungal metabolite (mycotoxin) occurring in foodstuffs. The compound is causally associated with mycotoxic porcine nephropathy, a disease comparable with a human kidney disease, Balkan endemic nephropathy. A preliminary survey of homeproduced foodstuffs in areas of Yugoslavia revealed that contamination with ochratoxin A is more frequent in an area where Balkan endemic nephropathy is prevalent (endemic area) than in an area where this disease is absent. This indicates higher exposure to foodborn ochratoxin A in the endemic area. Thus further evidence is provided supporting the hypothesis that ochratoxin A is a disease determinant of Balkan endemic nephropathy.

DIFFERENTIAL STAINING OF BACTERIA IN CLINICAL SPECIMENS USING ACRIDINE ORANGE BUFFERED AT LOW pH

Abstract: Optimal conditions for acridine orange staining of air dried and methanol fixed bacteria on glass slides were studied. The pH of the staining buffer did not influence the fluorescence of an S. aureus and an E. coli strain at dye concentrations of 25-50 mg per litre. 81 bacterial strains representing 15 different species were stained with acridine orange under standard conditions, all strains showing orange fluorescence. The pH of the buffer influenced markedly the staining patterns of human cells and tissue materials, as represented by smears of peripheral blood, buccal scrapings, urethral secretions and tracheal exudates. The fluorescence obtained ranged from low intensity green at low pH values to bright orange at neutral and alkaline pH. This variability indicated a possibility of designing conditions for a differential staining method for the detection of bacteria in clinical specimens. The differential staining effect with a low pH in the buffer was confirmed on smears of buccal scrapings, cerebrospinal fluid samples and urethral secretions, showing orange fluorescence of the bacteria present and green-to-yellow fluorescence of background material, cells and tissue debris.

The ultrastructural development of the macrogamete and formation of the oocyst wall of Toxoplasma gondii.

Abstract: The macrogametes of Toxoplasma gondii develop within the epithelial cells of the cat ileum. As they develop the nucleus enlarges and dense patches of chromatin which were present in the nucleoplasm, disappear. Polysaccharide granules and lipid globules appear in the cytoplasm and increase in number during development. The wall-forming bodies of Type I (WFB I) appear before the wall-forming bodies of Type II (WFB II); WFB I are smaller, more osmiophilic and more numerous than the WFB II. The WFB I appear to form from vesicles produced by the smooth endoplasmic reticulum, and the WFB II form within the lacunae of the rough endoplasmic reticulum. Double membraned vacuoles appear to form from the nuclear membranes but the function of these is unknown. Throughout development the macrogamete retains a normal pellicle which possesses numerous micropores. The first evidence of oocyst wall formation is the appearance of participate matter in the parasitophorous vacuole which precipitates to form Layer 1 of the oocyst wall. Layers 2 and 3 are unit membranes which form between Layer 1 and the pellicle. During this development the organism has an organelle complement similar to that of the macrogamete. Layers 4 and 5 form between Layer 3 and the pellicle. Layer 4 is osmiophilic and its formation is accompanied by the disappearance of WFB I. Layer 5 is less osmiophilic than Layer 4 and its formation is accompanied by the disappearance of WFB II. The two innermost layers (Layers 4 & 5) in the oocyst wall of Toxoplasma are similar to those found in Isospora spp. and Eimeria spp. Toxoplasma seems to be unusual in that, firstly, it possesses an additional 3 layers and, secondly, all 5 layers are formed outside the pellicle of the original macrogamete.

Serology of Neisseria gonorrhoeae. Classification by co-agglutination.

Abstract: The co-agglutination (COA) method has been adapted for serological classification of Neisseria gonorrhoeae. COA reagents were prepared with selectively absorbed rabbit hyperimmune antibodies against gonoccal (GC) major outer membrane protein (MOMP) serotype strains. Using these reagents, the 16 MOMP reference strains could be referred to at least three antigen classes, tentatively named W, J and M. The GC antigens of class W were divided into three groups I, II and III, and they were in part sensitive to pronase. The antigens of class J reflected strain specific or serotype reactions, some sensitive and others resistant to proteolytic enzymes. The antigens of class M were sensitive to periodate and resistant to pronase. Strains used in serological studies by other authors were tested. The properties of class W correlated well with those of the so-called micro-immunofluorescence and immunotype systems, and class M with those of the so-called endotoxin and acid polysaccharide systems. Strains from three different laboratories could all be grouped by class W and M reagents. Identical strains obtained independently from different laboratories gave very similar reaction patterns with the reagents available. Repeated GC-isolates from patients infected with beta-lactamase producing strains showed stable reactions with class W and J reagents, while there was a time-related variation of the class M pattern. We have found that the COA method is rapid, easy and reproducible in the serological classification of Neisseria gonorrhoeae and all the 117 GC-strains tested could be classified.

The tendency of smooth and rough salmonella typhimuriumbacteria and lipopolysaccharide to hydrophobic and ionic interaction, as studied in aqueous polymer two‐phase systems

Abstract: In aqueous two-phase system, the partition of bacteria and lipopolysaccharide from a rough (R) strain (Rd-mutant) of Salmonella typhimurium is influenced by polymers with covalently linked hydrophobic groups indicating hydrophobic structures accessible at the cell surface. Furthermore, the partition of the R bacteria is influenced by a number of inorganic positive and negative ions, presumably as a consequence of interaction with negatively charged surface structures. In contrast, smooth (S) bacteria and lipopolysaccharide from the parent strain do not seem to participate in either hydrophobic or charge interaction indicating extensive hydrophilicity without charge. Thus, the S-specific polysaccharide side chain of S. typhimurium might serve the purpose of blindfolding aspecific host defence mechanisms dependent on hydrophobicity and charge. On the contrary, the R bacteria and R lipopolysaccharide have physico-chemical properties which predispose to interaction with several types of cells, organelles and molecules.

Escherichia coli o:h serotypes isolated from human blood

Abstract: Escherichia coli strains isolated from human blood obtained from 539 different patients all over Denmark were examined serologically for O and H antigens. 425 strains could be O grouped with O sera 1 to 150. 90 strains were spontaneously agglutinable. Using O sera to the ten most frequent O groups: 2, 4, 6, 75, 9, 8, 18, 7, 22 and 1, 57 per cent of all strains could be grouped. Using sera corresponding to the ten most frequent O and the ten most frequent H sera, it was possible to O:H type 68 per cent of all O groupable strains. The K1 antigen was detected in 18 per cent of the strains.

Enterotoxin, haemolysin and cytotoxic protein in aeromonas hydrophila from human infections

Abstract: Three different toxins were detected in culture supernatants from 11 strains of Aeromonas hydrophila. The haemolysin and the cytotoxic factor(s) interferred in the three test systems for enterotoxin, but they could be neutralized by heating at 56 degrees C or by specific antihaemolysin.

Yersinia enterocolitica and Yersinia like microbes isolated from mammals and water in Norway and Denmark.

Abstract: Data pertaining to 149 strains belonging to genus Yersinia are summarized in this paper. Yersinia enterocolitica (Y.e.) was isolated from the faeces of 31 of 305 small rodents and from 5 of 31 shrews (Soricidae) trapped at five localities in Norway and one locality in Denmark. Isolations were obtained from 9 of 29 water samples collected within the trapping areas. Three of 25 red foxes (Vulpes vulpes) from one locality in Norway harbored Y.e. in their faeces. Y.e. serotype 16 was isolated from one zoologist suffering from diarrhoea. A total of 85 strains from small rodents, shrews, water and foxes showed biochemical properties intermediate to Y.e. and Y. pseudotuberculosis. Another three strains were classified as Y. pseudotuberculosis on biochemical basis. They were obtained from small rodents in Denmark. Serological examination of 59 small rodents naturally infected with Y.e. and related microbes, revealed two cases of low antibody titres (80) against homologous isolates. Pathological examination of 44 of these animals gave a negative result. Strains antigenically related to the same serotypes were frequently isolated from both terrestrial ecosystems and adjacent freshwater. Strains related to serotype 6 dominated both in red fox and in their small rodent prey. No evidence was found for a dynamical significance of Y.e. in populations of small rodents. The results indicate that Y.e. and Yersinia like microbes have a broad occurrence in terrestial ecosystems.

Lethality for mice and chick embryos, pyrogenicity in rabbits and ability to gelate lysate from amoebocytes of Limulus polyphemus by lipopolysaccharides from Bacteroides, Fusobacterium and Veillonella

Abstract: Phenol-water extracted lipopolysaccharides (LPS) from Veillonella, Fusobacterium nucleatum, Bacteroides fragilis and Bacteroides melaninogenicus were lethal for mice and 11-days-old chick embryos, pyrogenic in rabbits, and gelated Limulus amoebocyte lysate. Mouse lethality was considerably enhanced by actinomycin-D. In all test systems the endotoxin activity of Veillonella and Fusocbacterium LPS was comparable to that of LPS from Salmonella enteritidis, which was included as a reference endotoxin. The endotoxicity of the Bacteroides LPS was very low. While nanograms of the Veillonella and Fusobacterium LPS killed the chick embryos and gelated the Limulus lysates, microgram amounts of the Bacteroides LPS were needed to give positive reaction in the same test systems. As much as 74 microgram of the most active B. fragilis LPS were required to give a typical biphasic fever response in rabbits. A significant correlation was found between all test results (r = 0.90-0.98, p less than 0.001).

Raising antibodies to human leukocyte interferon

Abstract: Human leukocyte interferon proved to be a good immunogen in sheep, rabbits and guinea pigs. Sera from immunized animals neutralized the antiviral action of leukocyte interferon at high dilution. The highest anti-interferon titres obtained were 1:1,200,000 for sheep, 1:150,000 for rabbits, 1:30,000 for guinea pigs. Partial purification of human leukocyte interferon, by ethanol precipitation, improved its qualities as an immunogen. While it appeared more efficient to give initial injections without adjuvant, the inclusion in booster injections, of Freund's complete adjuvant produced a markedly superior response and, in one sheep, maintained high levels of circulating antibody for several months.

Epidemiology of pseudomonas aeruginosa infection in patients treated at a cystic fibrosis centre

Abstract: 484 isolates of P. aeruginosa were obtained from the respiratory tract of 45 out of 70 cystic fibrosis (CF) patients of monthly examinations during one year at the Danish CF Centre. All isolates were serogrouped (O-antigens) and phage typed, and in this way 99 per cent of the isolates could be grouped and/or typed. The isolates from CF patients belonged to many different sero-groups, but 55 per cent were polyagglutinable, and most of these belonged to the 0-3/9 complex. This was significantly different from the distribution into O-groups of isolates obtained from non-CF patients. The results of the combined phage typing and sero-grouping of the isolates revealed the occurrence of 13 clusters of distinct epidemiological types of P. aeruginosa among small groups (2-10 individuals) of CF patients. The predominating endemic strain, which was isolated from 10 (22 per cent) of the patients, belonged to the 0-3/9 complex and was lysed by phage 109, either alone or in combination with a few other phages. Furthermore, in a few cases the eradication of another strain of P. aeruginosa by chemotherapy was followed by colonization of the lungs with the above-mentioned predominating strain, and this strain was associated with high lethality. According to these results, measures should be undertaken to identify and eliminate routes of cross-infection in CF centres in order to diminishe the prevalence of P. aeruginosa infection and thereby reduce the lethality of CF patients.

Separation and characterization of enterotoxin and two haemolysins from Aeromonas hydrophila.

Abstract: Aeromonas hydrophila produces two haemolysins, now designated alpha- and beta-haemolysin (formerly aerolysin or cytotoxic protein), and one enterotoxin. These toxins were separated and purified by isoelectric focusing and gel chromatography. Alpha- and beta-haemolysin differ with regard to prerequisites for their elaboration, such as selection of A. hydrophila strains and temperature and time for cultivation. The nature of their lytic effects on erythrocytes and toxic effects on tissue culture cells differs significantly. Alpha- but not beta-haemolysin was inactivated by reducing agents and activated by oxygen, while beta-haemolysin was more resistant than alpha-haemolysin to proteolytic enzymes but was inactivated by crude gangliosides. When separated from the two haemolysins, the enterotoxin gave positive reactions in the rabbit intestinal loop test, the rabbit skin and the adrenal Y1 cell test, though the sensitivity of the Y1 cell was low as compared with cholera toxin and E. coli LT toxin. No cytotoxic effects were obtained in HeLa cells.

The use of protein A-containing staphylococci sensitized with anti-meningococcal antibodies for grouping Neisseria meningitidis and demonstration of meningococcal antigen in cerebrospinal fluid.

Abstract: The co-agglutination technique, utilizing antibody coated protein A-containing staphylococci, was successfully adapted to grouping N. meningitidis strains. It was found to give more clear-cut results than the standard slide test, especially in the case of strains isolated from throat specimens. The co-agglutination technique has also other advantages over the standard slide test in the grouping of meningococci: minor influence by auto-agglutination, higher specificity, easy performance and low consumption of specific antisera. Preliminary results also showed that the co-agglutination technique could be applied for the rapid detection of meningococcal antigen in cerebrospinal fluid.

Fibrinogen binding structures in beta-hemolytic streptococci group A, C, and G. Comparisons with receptors for IgG and aggregated beta 2-microglobulin.

Abstract: Binding of radiolabelled fibrinogen was measured to 197 strains of 16 different bacterial species. All streptococcal strains belonging to groups A, C, and G isolated from human sources were strongly positive. S. aureus strains showed low binding values. Occasional group B streptococci were positive. Reactive strains were also noted among group C streptococci of animal origin, Streptococcus zooepidemicus and Str. equii, and bovine beta-hemolytic group G streptococci. Bovine alpha-hemolytic group G strains as well as the remaining seven species of human origin were all negative. Inhibition experiments and correlation studies indicated that the streptococcal receptor for fibrinogen was different from immunoglobulin Fc binding reactivity. Comparisons with the newly discovered beta 2-microglobulin binding factor showed that trypsin concentrations which destroyed this receptor left the fibrinogen receptor intact. Although the two receptors correlate in strain population studies and show competition for binding the difference in trypsin sensitivity indicates that they represent two different structural entities. Both receptors might serve as basic markers for M-protein like surface components of Gram positive cocci.

The occurrence of twitching motility among gram-negative bacteria

Abstract: Almost 1000 strains representing well above 50 different species or groups of gram-negative bacteria were examined for twitching motility. This kind of motility was mainly found in strictly aerobic cocci and rods (viz. Acinetobacter calcoaceticus, Moraxella spp., Neisseria gonorrhoeae, N. meningitidis, Pseudomonas spp., phenon 3 of Thornley that is closely related to Acinetobacter, and marine, yellow-pigmented rods), but also in the facultative Eikenella corrodens and in anaerobic strains presumptively identified as "Bacteroides corrodens" earlier. Strains of species known to possess polar fimbriae were shown to exhibit twitching motility. None of the strains of species known to possess peritrichously arranged fimbriae exhibited twitching motility.

Experimental acute salpingitis in grivet monkeys provoked by Chlamydia trachomatis.

Abstract: Chlamydia trachomatis is a common cause of sexually transmitted diseases. Recently it has been shown that chlamydiae are also responsible for complications to such lower genital tract infections. In this study, isolates of C. trachomatis from the fallopian tubes of patients with acute salpingitis were inoculated direct into the fallopian tubes of two, and through the cervical canal into the uterine cavity of one grivet monkey. The experimental infections resulted in a self-limited acute salpingitis in the three animals. C. trachomatis was recovered from the monkeys 2 and 3 weeks post inoculation. As found at laparotomy, the infected tubes were swollen and reddened, and there was watery exudate in the abdominal ostia. Microscopically, cellular infiltrates--mainly lymphocytes--were seen in the mucosa, muscularis and subserosa of the tubes. Serologically, a primary antibody response with an IgM to IgG conversion was found. Salpingitis did not occur in a control monkey inoculated in the tubes with a medium lacking Chlamydia. The histological changes in the fallopian tubes of the infected monkeys were reminiscent of those described as being characteristic of "gonococcal" salpingitis in man. The fulfilment of Koch's postulates in the animal model used adds to the earlier evidence that C. trachomatis is capable of causing acute salpingitis in humans.

Experimental endocarditis in rabbits. 3. Significance of the proteolytic capacity of the infecting strains of Streptococcus faecalis.

Abstract: Insertion of a polyethylene catheter into the left ventricle of the heart was used for regular establishment of sterile endocarditis, and bacterial endocarditis was established by injection of approximately 10(8) Streptococcus faecalis into the blood stream at the same time as removal of the catheter which had been in place for 3 days. 100 out of 102 rabbits died spontaneously of bacterial endocarditis. Evidence is produced that the host-parasite interaction is influenced by the proteolytic property of S. faecalis in this experimental model. Two distinct types of clinical course are described: 1) A predominantly acute and damaging illness, characterized by a high level of bacteraemia, small amounts of soft, friable vegetations in the left side of the heart, high frequency of kidney infarcts and shorter survival time in rabbits infected with proteolytic strains. 2) A relatively subacute illness, characterized by a lower level of bacteraemia, large, hard, non-friable vegetations on the aortic valves, less pronounced destructive changes in the substance of valve leaflets, relatively lower frequency of kidney infarcts and longer survival time in rabbits infected with non-proteolytic strains. The results suggest that proteolytic strains of S. faecalis cause partial dissolution of the vegetations resulting in a more severe clinical picture.

Deoxyribonucleic acid hybridization between different species of mycobacteria.

Abstract: The homology percentages between DNA from M. smegmatis ATCC 607 and DNA from nine various species of mycobacteria have been determined. DNA-DNA hybridization was measured in a spectrophotometer. The technique, calculation of results and the uncertainty of the method are described.

Rapid identification of gram-negative rods using a three-tube method combined with a dichotomic key.

Abstract: A three-tube method combined with a dichotomic key is presented which will identify virtually all Enterobacteriaceae as well as a number of other frequently encountered Gram-negative rods at a genus or species level within 20 hours following the primary isolation. The method is shown to be reliable and simple, saving processing time and material.

Electron microscopy of Trichomonas vaginalis Donné: interaction with vaginal epithelium in human trichomoniasis.

Abstract: Light and electron microscopic examination of portio biopsies from eleven patients with trichomoniasis vaginalis revealed in four patients clusters of cells of T. vaginalis (T. vag.) which were attached to the vaginal mucosa. The minimum gap between adjacent trichomonad cells was the size of gap junctions (2 nm). Cells of T. vag. invaded superficially located epithelial cells but did not penetrate to the deeper cell layers of the epithelium. The latter, however, were frequently infiltrated with neutrophilic granulocytes. Contact between cells of T. vag. and neutrophils was not observed. Trichomonads which were attached to epithelial cells contained a dense network of cytoplasmic microfilaments in the part of the cell which came into contact with the epithelium. The remaining part contained the organelles normally seen in T. vag.. Endocytotic cell activity of amoeboid T. vag. occurred from the free cell surface only. A cell coat on the cell membrane--formed by bristles--was confined mainly to pinocytotic invaginations. Glycogen granules which were absent from the larger part of the epithelium were densely packed in the trichomonad cells. The findings in this study indicate that the interaction between the cells of T. vag. and the vaginal epithelium takes place primarily at a distance probably by means of substances released into the vaginal fluid, and secondly by a direct cell contact mechanism.

Endocytosis of salmonella typhimurium 395 ms and mr10 by hela cells

Abstract: Monolayer of HeLa cells were examined for their ability to endocytose Salmonella typhimurium 395 MS (wild) and MR10 (chemotype RD). Monolayers treated with the glycolytic inhibitors iodoacetic acid (IAA) or N-ethylmaleimide (NEM) or the respiratory inhibitor sodium azide (NaN3) or cytochalasin B (CB) were incubated with S. typhimurium. The numbers of cell-associated (intracellular plus cell-membrane attached extracellular) and intracellular bacteria were determined by viable counts, together with the HeLa cell ATP levels. IAA and NEM at concentrations 10(-4)M and 10(-3)M decreased significantly the number of intracellular MR10 and the cellular ATP levels, but did not influence significantly the total number of cell-associated bacteria except for 10(-3)M IAA which slightly increased the association. On the other hand, NaN3 at concentrations 10(-4)M and 10(-3)M did not affect the number of associated or intracellular bacteria, or the cellular ATP levels. CB at concentrations of 5, 10 and 20 microgram/ml increased the number of associated bacteria, decreased the number of intracellular bacteria and caused a small decrease in cellular ATP levels. Thus, HeLa cells may internalize S. typhimurium by an energy-requiring, glycolysis-dependent process. CB had a dose-dependent inhibitory effect on the internalization without influencing significantly the HeLa cell ATP levels. This indicates that CB might affect the internalization process by some means other than decreasing the ATP content.

Twitching motility and possession of polar fimbriae in spreading Streptococcus sanguis isolates from the human throat.

Abstract: A collection of 19 strains of alpha haemolytic streptococci, isolated from throat swabs and characterized by production of spreading zones around colonies on blood agar, was found to constitute a very homogeneous group with morphological, physiological and biochemical characters corresponding to those of streptococci of ser-group H, or Streptococcus sanguis, and they all appeared to possess the group H antigen. They all had a common agglutinogen and, in addition, heterogeneous agglutinogens. The spreading growth, which appears to be a common property of S. sanguis, was due to twitching motility, and the spreading cultures possessed polar fimbriae. tneither twitching motility nor the possession of polar fimbriae have been observed in gram-positive bacteria before.

Microbial aggregate contamination of water lines in dental equipment and its control

Abstract: Water from some dental clinics has been examined and found to be discoloured, badly tasting and with a foul odour. Moreover, brown or black flakes were often present in tap water, as well as in the water lines of dental equipment. Examination by phase-contrast and electron microscope showed the flakes to consist of aggregated fungi and bacteria, and similar structures were found in a layer on the inner surfaces of the clinics water tubes and pipes. The ultrastructure of some aggregating microorganisms, including fungal hyphae and sheath-forming and stalked bacteria, was studied in detail, and several modes of aggregation were suggested. Cultivation of contaminated water samples revealed the presence of filamentous fungi, including Cladosporium and Cephalosporium, and of non-fluorescent Pseudomonas, Aeromonas, Acinetobacter, Alcaligenes, Flavobacterium, and Moraxella (?). Removal of microorganisms from the walls of the tubing was effectively accomplished by rinsing with the non-corrosive solution of 4 per cent Tween 80, coloured with Ponceau 4 R.

Surface properties of Staphylococcus saprophyticus and Staphylococcus epidermidis as studied by adherence tests and two-polymer, aqueous phase systems.

Abstract: S. saprophyticus is an established pathogen in man, devoided of characteristics associated with pathogenicity in Staphylococcus aureus. The ability of this species to attach to cells from regions, viz. the urinary tract, where it acts as an invador and to cells from areas where it is known as a commensal, was compared to its behaviour in this respect with another staphylococcal species, viz. S. epidermidis. S. saprophyticus showed a preferenital adherence to human exfoliated urogenital cells, when compared with its ability to attach to skin and buccal cells from man and also when compared with procine cells from these regions. The profound ability to adhere to human exfoliated urogenital epithelial cells by far exceeded that of S. epidermidis, while no such species difference was found when testing porcine cells (S. saprophyticus is unknown as a urogenital tract pathogen in pigs). When studied in a two-polymer, aqueous phase system, S. saprophyticus and S. epidermidis were found to have a negative surface charge at pH 7.2, but the former carried a considerably higher surface charge density. Both staphylococcal species exhibited a poor hydrophobic interaction liability. These physico-chemical surface characteristics are briefly discussed with regard to the differential bacteria-cell interactions of these species.

Prevalence of mucoid strains of Pseudomonas aeruginosa in bacteriological specimens from patients with cystic fibrosis and patients with other diseases.

Abstract: The relative prevalence of mucoid strains compared with non-mucoid strains of Pseudomonas aeruginosa has been investigated in all routine bacteriological specimens received in a department of clinical microbiology during 1973. Pseudomonas aeruginosa was isolated from 1054 of the specimens (5.7 per cent) representing 53 patients with cystic fibrosis (551 isolates) and 169 patients with other diseases (503 isolates). The relative prevalence of mucoid strains was significantly higher in specimens from patients with cystic fibrosis (80 per cent) than in specimens from patients with other diseases (3 per cent). Considering patients without cystic fibrosis, the relative prevalence of mucoid strains was low in specimens from all anatomical regions, and no special preference of these strains for the respiratory tract could be demonstrated in these patients, in contrast to the situation in patients with cystic fibrosis. Alternation between mucoid strains and non-mucoid strains in subsequent specimens was observed in 33 of the patients.

Correlation between twitching motility and possession of polar fimbriae in Acinetobacter calcoaceticus.

Abstract: Negatively stained preparations of 16 strains of Acinetobacter calcoaceticus were examined in the electron microscope. Five of the strains did and 11 of the strains did not exhibit twitching motility. Two of the non-twitching strains were substrains of twitching wild-type strains. All twitching strains were found to possess fimbriae with a diameter of approximately 50 A. These fimbriae were shown to be of polar origin except in one strain where, for technical reasons, the origin could not be determined with certainty. Polar fimbriae could not be demonstrated in any of the strains that did not exhibit twitching motility. The demonstration of polar fimbriae was only regularly possible during the exponential growth phase, presumably because the fimbriae are shed by the bacteria during later growth phases. During the study, methods were developed for securing exponentially growing bacteria in concentrations suited for the preparation of negatively stained cells for electron microscopy. Peritrichously arranged fimbriae with a diameter of approximately 30 A were demonstrated in nearly all strains studied, especially on cells in late growth phases. The occurrence of this kind of fimbriae was therefore not correlated with the occurrence of twitching motility.

Complete and incomplete Ibc protein fraction in group B streptococci.

Abstract: The Ibc protein fraction of group B streptococci was isolated from the type Ib strain H36B, the type Ic strain A909, and the type Ic strain 335, and examined against antisera by immunodiffusion and immunoelectrophoresis. The fraction from the Ib strain and one of the Ic strains (A909) contained two antigens or groups of antigens, called the alpha and beta antigens, respectively. Strain 335 produced the alpha but not the beta antigen. This was also the case with three other group B isolates previously classified as type Ic. One type II and one type III strian produced both antigens. The results suggest that group B streptococci producing the Ibc fraction can be subdivided further on the basis of the antigens that are present in that fraction.