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J C Wilt

Publications and source records attributed to J C Wilt.

At least 19 recordsLinked to original sources
PubMed1978

Antimicrobial susceptibility of Haemophilus ducreyi.

The susceptibility of 19 isolates of Haemophilus ducreyi from a recent chancroid outbreak and four reference strains was determined in vitro to 13 antimicrobial agents. The rabbit intradermal test for virulence was positive for all of the local isolates, but not for the reference strains. The "nonvirulent" reference strains were inhibited by lower minimum inhibitory concentrations (MICs) of most agents tested. For the virulent isolates, the range of MICs (in micrograms per milliliter) of the following were: of vancomycin, 8 to 128; of polymyxin, 32 to 128; of cloxacillin, 32 to 64; of tetracycline, 0.5 to 32; of cephalothin, 4 to 8; of doxycycline, 0.25 to 8; and of kanamycin, 1 to 8. Three strains were resistant to penicillin and ampicillin (MIC >/= 128 mug/ml), and these three strains produced beta-lactamase. The remainder were susceptible to 4 mug/ml. All strains were susceptible to rifampin (MIC </= 1 mug/ml), chloramphenicol (MIC </= 4 mug/ml), sulfisoxazole (MIC </= 8 mug/ml), and nalidixic acid (MIC </= 8 mug/ml). These susceptibilities of H. ducreyi indicate several antimicrobial agents that may be effective for chancroid treatment and support the use of vancomycin in a selective medium for the culture of chancroid genital ulcers.

Animals↗
PubMed1978

Comparison of specimen collection and laboratory techniques for isolation of Haemophilus ducreyi.

Sixteen patients with clinical chancroid were studied prospectively; different culture media and sampling techniques from genital lesions were evaluated. Technique A was aspiration of a saline wash from the ulcer which was pooled and inoculated into rabbit blood, rabbit blood + vancomycin (5 microgram/ml), and semisolid chocolate agar + vancomycin (3 microgram/ml). Each primary culture medium was subcultured to chocolate agar with 1% IsoVitaleX (CA), CA with vancomycin (3 microgram/ml) plus polymyxin (7.5 microgram/ml; CA + vp). Technique B was the use of a cotton swab, plated directly on CA, CA + v, and CA + vp. Nine strains of Haemophilus ducreyi were obtained. Technique A yielded seven strains, whereas technique B yielded eight strains; with each technique, five strains were isolated only after use of selective antibiotic media. CA + v medium yielded the largest number of isolates. Direct inoculation by swab to CA + v from chancroidal ulcers is effective as an isolation technique for growth of H. ducreyi.

Bacteriological Techniques↗
PubMed1978

Determination of the hemin requirement of Haemophilus ducreyi: evaluation of the porphyrin test and media used in the satellite growth test.

Gonococcal (GC) agar supplemented with glucose and glutamine was found to be superior to Eugonagar and Trypticase soy agar in demonstrating the hemin requirement of 23 strains of Haemophilus ducreyi by the satellite growth test. The porphyrin test confirmed the requirement for exogenous hematin. With the agar dilution technique, using supplemented GC agar, the hemin concentration required to initiate growth was 10 microgram/ml, and the optimal hemin concentration to produce growth equivalent to that on chocolate agar was between 200 and 500 microgram/ml. On GC agar with added glucose and glutamine, the lowest hemin concentration impregnated in paper disks able to initiate satellite growth was 50 microgram/ml. The hemin requirements of these H. ducreyi were much higher than that reported for other Haemophilus species.

Bacteriological Techniques↗
PubMed1977

Sucrose density differences of Chlamydia psittaci 6BC in relation to its host.

Previous studies on Chlamydia psittaci 6BC propagated in different hosts have shown differences in cytotoxicity but no differences in the ultrastructure of the individual particles. It is shown here that the 6BC strain derived from yolk sac of infected chick embryo sedimented in sucrose gradients at lower densities than the 6BC strain derived from L-cells. Host-related modifications of lipid concentrations of the 6BC strains have been previously documented by others. It is thought that the phenomenon of host-induced modifications of physical properties of the agent might provide a new approach to the study of chlamydial pathogenicity.

Animals↗
PubMed1976

Autoradiography of [3H]thymidine-labeled Chlamydia psittaci 6BC in mononuclear phagocytes.

Incorporation of tritiated [3H]thymidine by Chlamydia psittaci 6BC was achieved by growing the parasites in chick embryo yolk sac explants which were exposed to exogenous labeled thymidine. These labeled, purified chlamydiae were next observed by autoradiography within mouse peritoneal macrophages. The number of silver grains remained constant in the cytoplasm of macrophages throughout the developmental cycle of the parasite. The proliferation of labeled chlamydiae in macrophages was confirmed by Giemsa staining and immunofluorescence. Chlamydiae have never been successfully labeled with thymidine in earlier studies when assayed in cultured mammalian fibroblasts. It is suggested that a critical factor in the successful incorporation thymidine in chlamydiae may be the host-parasite system used.

Animals↗
PubMed1976

Alterations in the ultrastructure of Chlamydia psittaci 6BC harvested from the allantoic fluid of chick embryos.

The allantoic fluid of chick embryos infected with Chlamydia psittaci is routinely used as a source of material for the study of the chemical and biological properties of the chlamydiae. We have examined pellets recovered from this allantoic fluid by low- and high-speed centrifugation, as well as high-speed pellets which had been stored at -70 degrees C, and we find that all of the pleomorphic forms of the chlamydiae are present in these materials. The reticulate bodies and large intermediate bodies are always seen to be morphologically damaged in that their cell envelopes are modified and in that they are distended and occasionally 'leaky.' No morphological evidence of damage was seen in small intermediate bodies or in elementary bodies in any of the materials which were examined. Thus the chlamydial population recovered from the allantoic fluid of infected chick embryos has been modified by selective damage to the least-condensed particles. We propose that the release of lysosomal enzymes from the host cell may coincide with the release of the chlamydia and that these enzymes may be responsible for this selective damage.

Allantois↗
PubMed1976

Ultrastructural studies of the nucleoids of the pleomorphic forms of Chlamydia psittaci 6BC: a comparison with bacteria.

The nucleoids of the various pleomorphic forms of Chlamydia psittaci have been examined by direct observation of infected cells and by observations on isolated particles. The fixation and staining methods used were the same as those routinely used for the examination of bacteria to facilitate the comparison of chlamydial fine structure with that of bacteria. The nucleoids of reticulate bodies were composed of fine fibrils which extended throughout these particles. The nucleoids of intermediate bodies are characterized by an electron-dense mass with which the fibrous elements are associated in a structurally coherent manner. As condensation of the intermediate bodies proceeds, the electron-dense mass becomes eccentrically located and the fibers form a distinct radiating structure. Large elementary bodies have a few fibers associated with their condensed electron-dense nucleoids but the more condensed mature elementary bodies have a very discrete and homogeneous electron-dense nucleoid which is separated from the cytoplasmic elements of these particles by a very distinct electron-transparent space. These highly condensed elementary body nucleoids are usually ovoid, but may be elongated or irregular, and a small number of these structures react very strongly with ruthenium red. While the nucleoid structure of reticulate bodies resembles that of the bacterial cell, both the condensation process and the nucleoid morphologies which result from it in intermediate and elementary bodies have no parallels among the bacteria. Thus we conclude that major differences in nucleoid organization exist between the chlamydia and the bacteria.

Bacteria↗
PubMed1976

Differences in physicochemical and antigenic properties of chlamydial strains.

Antigenic analysis of Chlamydia psittaci, C. trachomatis, and Lymphogranuloma venereum (LGV) revealed basic physicochemical differences among the three chlamydial strains. These were manifested in structural, isoelectric points, absorption spectra, and in the characteristics of the chromophobe-containing proteins. The effective period of sonication for C. psittaci and C. trachomatis is around 60 min during which the linkages most susceptible to external sonication forces were broken, releasing all attainable cellular components. Denaturation studies demonstrated that less than 50% of protein content of C. psittaci was denatured after 1 h of sonication, only 5% in the case of C. trachomatis. The protein and carbohydrate content of the most reactive fractions in macrophage-spreading inhibition test were different for LGV and C. trachomatis. The structural differences appear to determine the antigenic properties observed among the chlamydial strains as well as the specificity and probably the mechanisms (s) of cellular immune reactivity to Chlamydiae. This in turn may explain the failure of chlamydial vaccines, prepared from stock strains, to protect immunized children against 'wild' chlamydial strains.

Antigens, Bacterial↗
PubMed1976

Phagocytic and chlamydiae-inhibiting activities of stimulated and nonstimulated periotneal mouse macrophages.

Phagocytic and chamydiacidal properties of nonstimulated and stimulated mouse mononuclear cells for two Chlamydia psittaci 6BC strains were investigated. It was determined that macrophages kept in monolayer culture (i.e. stimulated phagocytes) developed much more efficient chlamydiacidal ability than did cells kept in suspension directly after harvest (i.e. nonstimulated phagocytes). A thousandfold decrease of chlamydial infectivity was observed 60 min after induction of phagocytosis in stimulated macrophages, irrespective of the strain offered. In contrast, the infectivity of both chlamydial strains remained essentially unchanged up to 1 h after phagcoytosis by nonstimulated phagocytes. Electron-microscopic examination indicated that chlamydiae were disintegrated within phagolysosomes of stimulated phagocytes within minutes after phagocytosis, although ultrastructurally altered chlamydiae not enclosed in vacuoles were also observed in the cytoplasm of several mononuclear phagocytes at different times after phagocytosis.

Animals↗
PubMed1975

Lysosomes and the "toxicity" of Rickettsias. VI. In vivo response of mouse peritoneal phagocytes to L-cell-grown Chlamydia psittaci 6BC strain.

The L-cell-grown 6BC strain of C. psittaci inoculated intraperitoneally in mice induced an injurious effect on mononuclear phagocytes and their lysosomes; the influx of polymorphonuclear phagocytes (PMN's) increased markedly and the PMN's showed karyorrhexis and lysis. Cytochemical methods failed to detect chlamydial forms in peritoneal fluids from day 1 and up to 6 days after inoculation of mice. Chlamydial infectivity was not detected in either the cell-bound or the cell-free fractions of peritoneal cells from 6 h up to 6 days after inoculation of mice. In contrast, after infection of mice with the egg-grown 6BC strain, readily identifiable multiplication of the parasites occurred from 4 days after inoculation of mice; the lysosomes of macrophages were refractory to egg-grown 6CB particles that were initially ingested and the macrophages were nonspecifically "activated." Some of these "transformed" into large epitheloid cells containing numerous chlamydial inclusions in the cytoplasm. That lysosomes of "professional phagocytes" play a role in the "toxic" effect of virulent chlamydiae in the intact host is discussed.

Animals↗
PubMed1975

Immunofluorescence of peritoneal phagocytes after infection of mice with L-cell-attenuated Chlamydia psittaci 6BC.

Large amounts of particulate antigen of Chlamydia psittaci 6BC attenuated by growth in L cells were phagocytized by peritoneal mononuclear phagocytes during the 1st h after intraperitoneal inoculation. The phagocytes subsequently destroyed the immunofluorescent (IF) properties of the chlamydial antigens. It is suggested that the early damage of phagocytes by lysosomal enzymes activation induced by chlamydiae contributed to the relatively early disappearance of IF antigens from the peritoneal fluids.

Animals↗
PubMed1975

Electron microscopy of the in vivo internalization of virulent Chlamydia psittaci 6BC strain.

The internalization of virulent Chlamydia psittaci 6BC particles by wandering mononuclear phagocytes in the peritoneal cavity of intraperitoneally inoculated mice occurred asynchronously, i.e., fragile reticulate bodies (RB) appeared to be more readily phagocytized than the rigid elementary bodies (EB). Early damage of mononuclear phagocytes occurred after internalization of chlamydiae. This was followed by a decreased uptake of particles, and may explain the relatively long persistence (up to 6 h after inoculation) of free, extracellular, "swollen", and RB-like particles. Internalized particles within phagolysosomes showed varying degrees of disintegration. The subsequent influx of polymorphonuclear phagocytes and monocytes into the inflammed peritoneal cavity may explain the rapid disappearance of chlamydiae and their antigens from the peritoneal fluid. The alteration in ultrastructure of peritoneal cells and chlamydial parasites during the inflammatory process are discussed.

Animals↗
PubMed1975

Ultrastructural studies of Chlamydia psittaci 6BC in situ in yolk sac explants and L cells: a comparison with gram-negative bacteria.

Chlamydia psittaci (6BC) was grown in yolk sac explants and in L cells and fixed by perfusion in situ to provide undamaged material for comparison with gram-negative bacteria. Reticulate, intermediate, and elementary bodies were all seen to lack a well-defined periplasmic space; intermediate and elementary bodies showed condensations of the nucleoid which differ from common bacterial configurations; and the cytoplasm of highly condensed elementary bodies was much more electron dense than that of the gram-negative bacteria, while retaining its basically particulate nature. These important morphological distinctions are interpreted as reflections of a significantly different cellular level of organization in these two groups of organisms. No important morphological differences were noted in comparisons of the chlamydial particles grown in the two different host systems.

Animals↗
PubMed1975

The effect of purification on the ultrastructure and infectivity of egg-attenuated Chlamydia psittaci (6BC).

A procedure is described for the purification of mixed populations of the three different morphological forms of Chlamydia psittaci (6BC) from infected yolk sac membranes. Elementary bodies and small intermediate bodies are not perceptibly damaged during purification which involves homogenization of the host cells, differential centrifugation, sedimentation through 20% sucrose, and treatment with trypsin. The observation that elementary bodies undergo plasmolysis in 20% sucrose is interpreted as indicating that the cytoplasmic membrane of these particles is intact at that stage in the purification. Reticulate bodies and large intermediate bodies are damaged, to a degree, by the homogenization step. This damage takes the form of discontinuities of the outer envelope membrane, and results in the loss of the regular coccobacillary shape of these particles and in an increase in their size. Treatment with a combination of RNase and DNase was found to cause profound damage to all three morphological forms of the chlamydiae.

Animals↗