Evaluation of two commercial procedures for rapid identification of Neisseria gonorrhoeae using a reference panel of antigenically diverse gonococci

Two commercial tests for the rapid identification of Neisseria gonorrhoeae were evaluated. Two hundred seventy-nine organisms were tested, including 202 strains of N. gonorrhoeae. The Syva MicroTrak test results were less subjective but required a fluorescence microscope. The Phadebact Monoclonal GC OMNI Test required modification of the manufacturer's interpretive instructions in order to avoid cross-reactions, but it was a practical test. Specificities of both tests were 100%. Sensitivities of the Phadebact Monoclonal GC OMNI and Syva MicroTrak tests were 100% and approximately 100%, respectively.

Immune T cells sorted by flow cytometry confer protection against infection with Treponema pallidum subsp. pertenue in hamsters

The role of cell-mediated immunity against infection with Treponema pallidum subsp. pertenue in humans or experimental animals is unclear. Hamsters injected subcutaneously in the hind paws with 4 x 10(6) unfractionated lymph node cells or enriched lymph node T cells (immunoglobulin negative, Ia negative) from T. pallidum subsp. pertenue-immune hamsters were resistant to challenge with T. pallidum subsp. pertenue. The popliteal lymph nodes of hamsters that received immune cells weighed less and had significantly fewer treponemes than did lymph nodes from hamsters infused with cells from nonimmune donors. Furthermore, recipients of immune T cells failed to develop antitreponemal antibodies 21 days after challenge. Enriched T cells were obtained by flow cytometric separation by using monoclonal anti-Ia antibody 14-4-4s, which identified hamster B cells. Flow cytometric analysis by two-color immunofluorescent staining with anti-hamster-immunoglobulin and monoclonal anti-Ia antibody 14-4-4s confirmed that monoclonal anti-Ia antibody 14-4-4s recognized B cells. In addition, lymph node cells obtained after treatment with anti-Ia monoclonal antibody 14-4-4s and complement were 97% T cells, as determined by monoclonal antibody 20, a hamster T-cell marker. These results demonstrated that highly enriched T cells (immunoglobulin negative, Ia negative) from T. pallidum subsp. pertenue-immune hamsters conferred partial protection on hamsters against infection with T. pallidum subsp. pertenue.

Phagocytosis of opsonized Treponema pallidum subsp. pallidum proceeds slowly

Macrophages were found to phagocytize Treponema pallidum subsp. pallidum attached to polycarbonate filters. This environment simulated the in vivo interaction of surface-adherent treponemes with macrophages. The phagocytosis of T. pallidum subsp. pallidum was found to proceed slowly. Heat-killed T. pallidum subsp. pallidum were susceptible to opsonization with 2% immune serum, whereas live treponemes were resistant to this concentration of antibody. High concentrations of immune serum were found to increase phagocytosis of the spirochetes. Live T. pallidum subsp. pallidum had bound limited quantities of immunoglobulin G in vivo, and only opsonization with 20% immune serum resulted in a detectable increase in surface-bound immunoglobulin in vitro. Kinetic studies suggested a steady rate of phagocytosis that is considerably slower than with other bacteria. Scanning electron microscopy studies of the phagocytizing macrophages showed that the treponemes were detached from the membrane filters and scooped onto the ruffled portion of the macrophage surface. This lengthy physical process, along with the lack of a dramatic increase in ingestion after opsonization, may account for the slow rate of phagocytosis.

Rapid detection of bacteria in cerebrospinal fluid by immunofluorescence staining on membrane filters

A filter-fluorescent-antibody (FFA) staining procedure was developed for detection of bacteria in cerebrospinal fluid (CSF). The sensitivity of this procedure was determined and compared with that of the slide Gram stain of centrifuged samples, latex agglutination, and a previously developed filter Gram stain. Serial 10-fold dilutions of filter-sterilized CSF seeded with logarithmic-phase organisms were examined by each method and cultured to determine colony-forming bacteria. The bacteria included Haemophilus influenzae type b; Neisseria meningitidis group B, C, and W135; Streptococcus pneumoniae types 6A and 23F; and group B Streptococcus species. FFA was found to be equal in sensitivity to the filter Gram stain (P greater than 0.30). Both filter-staining procedures had greater sensitivity than the slide Gram stain of centrifuged sediment (P less than 0.02) and latex agglutination (P less than 0.0001). Addition of human leukocytes at a concentration of 5 to 10 cells per oil immersion field did not decrease sensitivity of the FFA procedure, although background fluorescence increased. FFA is a rapid and dependable procedure for detection of low numbers of bacteria in CSF. Evaluation of FFA with clinical specimens is needed.

Effects of bovine serum albumin on the ability of Barbour-Stoenner-Kelly medium to detect Borrelia burgdorferi

The ability of decreasing inocula of Borrelia burgdorferi to grow in otherwise identical Barbour-Stoenner-Kelly (BSK) media containing different lots of bovine serum albumin (fraction V) was determined. These media differed significantly in ability to detect B. burgdorferi. Some BSK media required inocula of 2 x 10(5) organisms per ml for detection, while other media could stimulate growth after inoculation with less than 2 organisms per ml. In addition, organisms from the less sensitive BSK media were thinner, longer, and less tightly coiled. The endpoint dilutions of indirect fluorescent-antibody titers, especially immunoglobulin M, exhibited up to 16-fold decreases, and both immunoglobulin G and M titers were more difficult to interpret with diagnostic slides prepared from some longer, thinner B. burgdorferi. These results demonstrate that, when performing laboratory investigations which rely on B. burgdorferi, it is essential that the quality of the BSK medium be determined.

Passive immunization prevents induction of Lyme arthritis in LSH hamsters

We determined that sera obtained from hamsters infected with Borrelia burgdorferi could prevent the induction of Lyme arthritis. When irradiated hamsters were administered immune serum and subsequently challenged with B. burgdorferi, no evidence of infection was detected. Recipients failed to develop swelling of the hind paws, and no histopathologic changes were detected. In addition, B. burgdorferi was not recovered from tissues of hamsters that were passively immunized. By contrast, irradiated hamsters that were administered normal hamster serum or saline and infected with the Lyme spirochete developed arthritis. Extensive histopathologic changes occurred in the hind paws and knee joints, and spirochetes were recovered from most of the tissues examined. These results show that immune serum can confer complete protection on recipient hamsters to challenge with B. burgdorferi.

The pathologist's view of Lyme disease

Lyme disease is a multisystem disease caused by the spirochete Borrelia burgdorferi and is transmitted to humans primarily through Ixodid ticks. The clinical spectrum of the disease is continuing to expand while in its wake the pathology and histopathologic manifestations are being uncovered. We review the pathology of Lyme disease in man beginning with the tick bite. We present the pathologic changes of the rash, erythema migrans, as well as the neurologic, cardiac, and arthritic changes of the disease. We can expand our understanding of the immunobiology of Lyme disease by studying the interactions of B. burgdorferi in an experimental animal model.

Phagocytosis of Treponema pallidum pertenue by hamster macrophages on membrane filters

The role of the macrophage in destruction of virulent treponemes is disputed. A major obstacle has been the inability to demonstrate quantitative phagocytosis of treponemes by macrophages. Treponema pallidum pertenue was attached to polycarbonate filters for assessment of treponemal phagocytosis by macrophages. The disappearance of treponemes due to phagocytosis was measured by enumeration with immunofluorescence. Resident and lipopolysaccharide-activated macrophages were found to phagocytize treponemes equally well. The phagocytosis of killed treponemes by macrophages was enhanced by opsonization with immune serum. Macrophages successfully phagocytized Staphylococcus aureus organisms when they were incubated on filters under identical conditions. Treatment of macrophages with cytochalasin B, a known inhibitor of phagocytosis, prevented the disappearance of treponemes and phagocytosis of S. aureus. In addition, fluorescent treponemal debris was observed only inside macrophages cultured with treponemes. These results demonstrate that macrophages can phagocytize pathogenic treponemes on polycarbonate filters.

Development of a rapid method for determining the susceptibility of Mycobacterium tuberculosis to isoniazid using the Gen-Probe DNA Hybridization System

A rapid test was developed for determining the susceptibility of Mycobacterium tuberculosis to isoniazid by using nucleic acid hybridization. The method was based on quantification of total mycobacterial rRNA hybridized to a 125I-labeled DNA probe in the absence and presence of various concentrations of isoniazid. The radioactive hybridized complex was isolated by adsorption to hydroxyapatite crystals and measured in a gamma counter. The susceptibilities of four reference strains and 20 clinical isolates were compared by the Gen-Probe DNA Hybridization System and the critical concentration method. Overall agreement between the two methods was excellent. Results were obtained with the DNA probe after 3 to 5 days of incubation instead of the 14 to 21 days required for the critical concentration method. These findings indicate that susceptibility testing of M. tuberculosis by nucleic acid hybridization has merit for the clinical laboratory. Additional studies are needed to determine the efficacy of the DNA probe method for determining the susceptibility of M. tuberculosis to other antimycobacterial agents and its correlation with clinically significant levels of resistance.

Histopathology of Lyme arthritis in LSH hamsters

The authors studied the histopathologic evolution of arthritis in nonirradiated and irradiated hamsters infected with Borrelia burgdorferi. Nonirradiated hamsters injected in the hind paws with B. burgdorferi developed an acute inflammatory reaction involving the synovium, periarticular soft tissues, and dermis. This acute inflammatory reaction was short-lived and was replaced by a mild chronic synovitis as the number of detectable spirochetes in the synovium, periarticular soft tissues, and perineurovascular areas diminished. Exposing hamsters to radiation before inoculation with B. burgdorferi exacerbated and prolonged the acute inflammatory phase. Spirochetes also persisted longer in the periarticular soft tissues. A major histopathologic finding was destructive and erosive bone changes of the hind paws, which resulted in deformation of the joints. These studies should be helpful in defining the immune mechanism participating in the onset, progression, and resolution of Lyme arthritis.

Efficacy of the urinary bladder for isolation of Borrelia burgdorferi from naturally infected, wild Peromyscus leucopus

The efficacy of culturing urinary bladder tissue for Borrelia burgdorferi from naturally infected, wild Peromyscus leucopus mice was determined. The urinary bladder cultures were as efficient as spleen, kidney, and blood tissue cultures. The rapid B. burgdorferi isolation (mean, 6 days) from mouse urinary bladders should aid in defining new Lyme disease foci.

Borrelia burgdorferi infection surrounding La Crosse, Wis

This investigation defined the extent of Borrelia burgdorferi infection surrounding La Crosse, Wis. White-footed mice, Peromyscus leucopus or P. maniculatis, were captured from sites in Wisconsin, Minnesota, and Iowa and cultured for B. burgdorferi to define the local boundaries of the midwestern Lyme disease area. All foci of B. burgdorferi infection (N1, N2, N3, and N4) were located north of interstate highway 90 except focus S2, which was south of the highway near Fort McCoy, Wis. The interstate highway may have been a barrier to deer movement which slowed the southward dispersal of Ixodes dammini. B. burgdorferi was isolated from 12 (63%) of the mice captured from site N4, which was adjacent to the western border of Fort McCoy. Unexpectedly, no B. burgdorferi-infected mice were isolated at site N0, located north of interstate highway 90 and enclosed by areas in which B. burgdorferi infection is endemic. This site is surrounded by natural barriers which may have slowed the spread of I. dammini by deer. The Wisconsin area in which B. burgdorferi is endemic should now include the surrounding area north of interstate highway 90 west from Fort McCoy to the Mississippi River. Additional studies are needed to define the rapidity, limits, and means of I. dammini dispersal into southern Wisconsin.

Comparison of modified Bordet-Gengou and modified Regan-Lowe media for the isolation of Bordetella pertussis and Bordetella parapertussis

Culture and fluorescent-antibody methods for detection of Bordetella species were evaluated by two state public health laboratories. Field-inoculated plates of Regan-Lowe agar medium were most useful if incubation was initiated on the day of collection. Regan-Lowe and Bordet-Gengou media were comparable for subculturing nasopharyngeal specimens that were transported and enriched in half-strength Regan-Lowe agar. Maximum sensitivity was achieved when the media were used in parallel. Fluorescent-antibody-stained smears of nasopharyngeal specimens were more sensitive for detection of Bordetella pertussis than for detection of Bordetella parapertussis. The fluorescent-antibody method, however, was too insensitive for use without culture.

Induction of lyme arthritis in LSH hamsters

In studies of experimental Lyme disease, a major obstacle has been the unavailability of a suitable animal model. We found that irradiated LSH/Ss Lak hamsters developed arthritis after injection of Borrelia burgdorferi in the hind paws. When nonirradiated hamsters were injected in the hind paws with B. burgdorferi, acute transient synovitis was present. A diffuse neutrophilic infiltrate involved the synovia and periarticular structures. The inflammation was associated with edema, hyperemia, and granulation tissue. Numerous spirochetes were seen in the synovial and subsynovial tissues. The histopathologic changes were enhanced in irradiated hamsters. The onset and duration of the induced swelling were dependent on the dose of radiation and the inoculum of spirochetes. Inoculation of irradiated hamsters with Formalin-killed spirochetes or medium in which B. burgdorferi had grown for 7 days failed to induce swelling. This animal model should prove useful for studies of the immune response to B. burgdorferi and the pathogenesis of Lyme arthritis.

Synergistic effect of macrophage activation and immune serum, especially IgG2, on resistance to infection with Treponema pallidum ssp. endemicum in hamsters

Experimental studies have indicated that macrophages are involved in the pathogenesis of syphilis. Whether macrophages alone or with immune serum are ultimately responsible for killing of treponemes is disputed. We have demonstrated that BCG-vaccinated hamsters administered normal serum contained fewer treponemes in the inguinal and popliteal lymph nodes than did the nonvaccinated controls. When BCG-vaccinated hamsters were injected with syphilitic immune serum and challenged with Treponema pallidum ssp. endemicum, treponemicidal activity was enhanced. Treponemicidal activity was also detected in BCG-vaccinated hamsters challenged with treponemes treated in vitro with immune serum and its immunoglobulin fractions, especially IgG2. The immune IgG2 fraction had more treponemicidal activity than did the immune IgG1 fraction and the unfractionated immune serum. Our observations indicate an important synergistic role for macrophages and immune serum, especially IgG2, for elimination of T. pallidum ssp. endemicum from the host.

Rapid method for the differentiation of gram-positive and gram-negative bacteria on membrane filters

Microfiltration has become a popular procedure for the concentration and enumeration of bacteria. We developed a rapid and sensitive method for the differentiation of gram-positive and gram-negative bacteria, utilizing a polycarbonate membrane filter, crystal violet, iodine, 95% ethanol, and 6% carbol fuchsin, that can be completed in 60 to 90 s. Gram reactions of 49 species belonging to 30 genera of bacteria were correctly determined by the filter-Gram stain. The sensitivities of the filter-Gram stain and conventional slide-Gram stain were compared by testing dilutions of Escherichia coli, Neisseria meningitidis, Streptococcus pneumoniae, and Haemophilus influenzae suspensions in the presence and absence of whole human blood. The filter-Gram stain was approximately 100-fold more sensitive than the slide-Gram stain. The filter-Gram stain detected 2 to 100 bacteria, whereas the slide-Gram stain failed to detect less than 1,000 bacteria. The sensitivities of the methods were not significantly altered by the addition of whole human blood to the dilutions of bacteria tested. The filter-Gram stain could be a useful tool for the examination of body fluids with very low numbers of bacteria.

Antimicrobial susceptibilities of Bordetella species isolated in a Multicenter Pertussis Surveillance Project

MICs for 90% (MIC90s) of 75 Bordetella pertussis strains for amoxicillin, erythromycin, rifampin, and sulfamethoxazole-trimethoprim were 1, less than or equal to 0.12, 1, and 4 micrograms/ml, respectively. Susceptibility rates were all greater than or equal to 93%. Only 17% of the strains were susceptible to tetracycline. The MIC90s of ciprofloxacin, enoxacin, norfloxacin, ofloxacin, and roxithromycin were less than or equal to 0.06, 0.5, 0.25, 0.12, and 0.5 micrograms/ml, respectively. For B. parapertussis, the MIC90s were 16-fold higher with amoxicillin and rifampin and 2- to 4-fold higher with the fluoroquinolones and roxithromycin.

Case report of an unclassified microaerophilic bacterium associated with gastroenteritis

An unusual microaerophilic gram-negative bacterium was isolated from the stools of two individuals presenting with chronic diarrhea. This bacterium resembled Campylobacter species by colonial morphology and biochemical reactions. However, microscopic examination revealed a fusiform rod with a corrugated surface, rather than a spiral rod. This is the first reported isolation of this bacterium from humans.

Characterization of an unclassified microaerophilic bacterium associated with gastroenteritis

Four isolates of an unclassified microaerophilic bacterium resembling Campylobacter species were characterized by growth requirements, microscopic examination, biochemical characteristics, antimicrobial susceptibility tests, and protein profile analysis. The unclassified isolates were differentiated from Campylobacter jejuni, Campylobacter coli, Campylobacter fetus subsp. fetus, Campylobacter laridis, Campylobacter pylori, and an ovine isolate. The bacterium was fusiform shaped with a corrugated surface due to the presence of periplasmic fibers and had multiple bipolar flagella. Biochemically, the bacterium was separated from the Campylobacter controls by its negative catalase reaction, negative nitrate reduction, and no growth in 1% glycine. It was also resistant to ampicillin. Protein profile analysis demonstrated nine major protein bands present in the unclassified isolates that were absent in the Campylobacter controls. The bacterium also differed from the ovine isolate by its negative catalase reaction, rapid urea hydrolysis, and susceptibility to clindamycin, erythromycin, and tetracycline. Our results showed that the unclassified bacterium was distinct from the recognized Campylobacter species.

Identification of Yersinia spp. with the API 20E system

The ability of the API 20E system to identify 105 clinical isolates of Yersinia spp. was compared with those of conventional biochemical tests at 28 and 37 degrees C. Elimination of the Voges-Proskauer test (recorded as a negative result) increased the percentage of correct identifications for Yersinia spp. from 66 to 93% when the API 20E strips were incubated at 28 degrees C.

Evaluation of a quantitative fluorescence immunoassay (FIAX) for detection of serum antibody to Borrelia burgdorferi

A quantitative, indirect, fluorescence immunoassay (FIAX; Whittaker Bioproducts, Inc.) was compared with the conventional indirect fluorescent-antibody test for detection of serum antibody to Borrelia burgdorferi. FIAX correlated well with the indirect fluorescent-antibody test (r = 0.72). FIAX is a convenient and dependable means of measuring serum antibody to B. burgdorferi.

Epidemiologic study of canine blastomycosis in Wisconsin

An epidemiologic study was designed to investigate the increasing number of cases of canine blastomycosis being reported in Wisconsin. From January 1980 through July 1982, 200 cases of canine blastomycosis from 39 Wisconsin counties were examined to assess epidemiologic and environmental aspects of this disease. Based on a survey of 176 dog owners, principal disease characteristics for canine blastomycosis were anorexia, lethargy, shortness of breath, chronic cough, and weight loss. The greatest number of cases of canine blastomycosis was in the northwest, north central, northeast, central, and southeast regions of Wisconsin. The northeast and central regions were determined to be new enzootic areas. Sporting breeds accounted for the largest percentage of cases among the various breeds of dogs in Wisconsin. Most of the affected dogs were 3 years old or younger and there was no apparent sexual predilection. Canine blastomycosis was diagnosed more frequently from late spring through late fall. Enzootic areas, except for the southeast region of Wisconsin, were located where the soil was sandy and acid. The results of this study suggested a possible association of enzootic areas with waterways, especially impoundments.

Treponema pallidum attachment to surface and matrix proteins of cultured rabbit epithelial cells

Treponema pallidum strain Nichols adheres readily to rabbit epithelial cells (SF1Ep) in tissue culture. We examined a variety of sugars for their ability to inhibit attachment. Mannose, galactose, and N-acetylgalactosamine showed minor but reproducible inhibition of attachment at high concentrations, whereas sialic acid was highly inhibitory even at low concentrations. Whole-cell lysates of SF1Ep cells contained a large number of glycoproteins, which might be related to the sialic acid-inhibitable attachment. When the cells and extracellular matrix were fractionated, only a few proteins were found in the matrix fraction. They included a 220-kilodalton (kDa) protein, shown by immunoblotting to be fibronectin, and an approximately 90-kDa protein (both were isolated on SDS-PAGE gels). When nitrocellulose replicas of these SDS-PAGE gels were exposed to 125I-labeled T. pallidum, adherence was mainly to the 90-kDa protein.