Phaeohyphomycotic cyst caused by a recently described species, Phaeoannellomyces elegans

An 81-year-old man presented with a chronic, painful nodule on the palmar surface of the left fourth finger. As a former farm worker, the patient acknowledged frequent soil-contaminated wounds of the left hand 4 to 12 years previously, but he denied any recent trauma. The patient's other medical problems included a history of chronic immunoglobulin A gammopathy and a new pleural mass eroding into adjacent ribs on chest X-ray. The finger nodule was excised and consisted of an intact phaeohyphomycotic cyst which yielded growth of a darkly pigmented fungus. At 25 degrees C, the isolate formed annellidic yeast cells having dark-brown walls consistent with the recently described species Phaeoannellomyces elegans. In vitro antifungal susceptibility tests indicated resistance to amphotericin B and variable susceptibility to imidazoles. The lesion was excised, and the patient received no antifungal therapy. After 9 months of follow-up, the fungal infection shows no signs of recurrence.

A Legionella-specific DNA probe detects organisms in lung tissue homogenates from intranasally inoculated mice

We have prepared a DNA probe from internal sequences of the gene encoding the Legionella pneumophila major outer membrane protein (MOMP). Immunologic studies of the MOMP have confirmed that it possesses both genus-specific and species-specific antigenic domains, but possesses no cross-reactivity with non-Legionella species. At the DNA levels, the 3' half of the gene contains sequences that are homologous to DNA from all strains tested within the genus, whereas the 5' half of the gene has homology with L. pneumophila strains only. Homology of the gene with non-legionellae has not been detected even under low stringency conditions. To test the utility of this probe for detecting organisms in tissue, we tested crude homogenates of mouse lungs representing 1/1,000th of the total lung mass. After intranasal inoculation with 2 X 10(8) colony-forming units of L. pneumophila, mice were sacrificed at various intervals (10 mice per group). Since L. pneumophila does not produce a propagating infection in these animals, cultures of lung tissue from successive days after inoculation showed a roughly linear decline in viable L. pneumophila (total lung yield: 10(8) on Day 0, 5 X 10(7) on Day 2, 10(5) on Day 5, 10(3) on Day 9, and less than 10(2) on Day 15). By DNA dot hybridization with the MOMP probe, we detected positive signals from most animals on Days 0 and 2, suggesting a threshold sensitivity of between 50,000 and 100,000 organisms with our current methods. Advances in DNA probe technology may soon permit the rapid, specific identification of either L. pneumophila or other Legionella species in pathologic specimens.

Antibodies isolated by using cloned surface antigens recognize antigenically related components of Legionella pneumophila and other Legionella species

We studied the antigenic cross-reactivity of surface proteins among various strains of Legionella pneumophila and other Legionella species by using a novel method of antibody purification. Anti-bacterial antibodies in hyperimmune sera were adsorbed to and eluted from the surface of recombinant E. coli cells that express individual L. pneumophila antigens on their surface. These affinity-purified antibodies were then used to probe protein immunoblots prepared from the test strains to detect cross-reactive domains. We found that antigenic proteins are generally conserved in all L. pneumophila serogroups. Although some of these antigenic domains are shared with members of other Legionella species, they are associated with proteins of different molecular mass. Our approach to the study of antigenic cross-reactivity has potential advantages over similar studies that use either monoclonal antibodies or monospecific antibodies prepared by immunization with purified antigens.

Antibodies isolated by using cloned surface antigens recognize antigenically related components of Legionella pneumophila and other Legionella species

We studied the antigenic cross-reactivity of surface proteins among various strains of Legionella pneumophila and other Legionella species by using a novel method of antibody purification. Anti-bacterial antibodies in hyperimmune sera were adsorbed to and eluted from the surface of recombinant E. coli cells that express individual L. pneumophila antigens on their surface. These affinity-purified antibodies were then used to probe protein immunoblots prepared from the test strains to detect cross-reactive domains. We found that antigenic proteins are generally conserved in all L. pneumophila serogroups. Although some of these antigenic domains are shared with members of other Legionella species, they are associated with proteins of different molecular mass. Our approach to the study of antigenic cross-reactivity has potential advantages over similar studies that use either monoclonal antibodies or monospecific antibodies prepared by immunization with purified antigens.

Identification of protein antigens of Legionella pneumophila serogroup 1

Growth of Legionella pneumophila serogroup 1 in yeast extract broth was standardized, and protein profiles of detergent-solubilized cells were determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Over 30 protein bands were identified, 6 of which were more prominent both in Coomassie brilliant blue-stained profiles and in fluorograms with intrinsically radiolabeled bacteria. These major proteins were 22,000 dalton (22K), 24K, 43K, 63K, 76K, and 78K. We found that the 24K and 63K major proteins were antigenic, as demonstrated both by radioimmunoprecipitation (RIP) of [35S]methionine-labeled organisms and by immunoblotting with rabbit hyperimmune sera. In addition, both techniques detected antigens migrating at 58K, 72K, 76K, and 78K. The major 22K and 43K major proteins and antigens migrating at 25.5K, 29K, and 46K were only detected by radioimmunoprecipitation, whereas antigens of 19K, 48K, 53K, and 68K were detected only by immunoblotting. Cell-surface localization of the proteins was determined by a modified radioimmunoprecipitation assay designed to react specifically with surface antigens and by the use of hyperimmune sera that had been extensively preabsorbed with intact cells to deplete the sera of antibodies directed against surface components. The 22K, 24K, 43K, 63K, and 78K major proteins and several minor proteins were found to be located on the surface of L. pneumophila cells.

Legionella pneumophila surface antigens cloned and expressed in Escherichia coli are translocated to the host cell surface and interact with specific anti-Legionella antibodies

Escherichia coli clones that express Legionella pneumophila antigens were isolated from a plasmid genomic library, and their antigens were characterized by immunoblotting with rabbit anti-L. pneumophila sera. Because previous studies of L. pneumophila antigens by whole-cell radioimmunoprecipitation suggested that comigrating native antigens were surface localized, we conducted experiments to determine if the cloned antigens were surface expressed in E. coli. Aliquots of antisera were absorbed by intact cells of three representative antigen-producing E. coli clones, and surface-bound antibodies were acid eluted from the intact cells. Immunoblots made with selectively absorbed antisera and eluted antibodies confirmed that reactivity to the homologous cloned antigens could be specifically absorbed from the antisera and then eluted from the cells, demonstrating a surface (antibody-accessible) localization in the cloned state. Antibodies eluted from the surface of an E. coli clone that expressed a 19-kilodalton antigen reacted with the surface of L. pneumophila in a liquid-phase, whole-cell enzyme-linked immunosorbent assay. In addition, intact cells of this clone were used in an enzyme-linked immunosorbent assay to detect serum antibody. E. coli cells that express foreign antigens on their surfaces can be used to develop antigen-specific immunoassays and to affinity purify monospecific antibodies.

Campylobacter enteritis on Hopi and Navajo Indian reservations. Clinical and epidemiologic features

From June 22 through September 30, 1981, stool specimens from 522 Hopi and Navajo outpatients were cultured because of diarrheal illnesses at the Keams Canyon Indian Health Service Hospital, Arizona. Campylobacter jejuni was isolated from the specimens of 26 (5%) of the patients. This pathogen was found as frequently as Shigella in patients younger than 2 years or older than 20 years, but was significantly less common in the 2 to 20-year age group (P<.000001). Campylobacter enteritis was indistinguishable clinically from shigellosis in adult patients, but in children younger than 5 years, a rectal temperature higher than 38 degrees C (100.5 degrees F) was significantly more common with Shigella than with Campylobacter infection (P=.003). In a field study of 20 families, we found that households with a case of Campylobacter enteritis were more likely than age- and community-matched controls to own farm animals (P=.05), but were not more likely to own household pets. C jejuni is less common than Shigella as a cause of summer seasonal diarrhea and dysentery among the Hopi and Navajos; the striking differences in the age-specific rates of these two infections suggest different routes of transmission.

Cloning and expression of Legionella pneumophila antigens in Escherichia coli

To isolate and characterize Legionella pneumophila antigens, we constructed a genomic library of L. pneumophila serogroup 1 (strain 130b). L, pneumophila DNA fragments (2.5 to 7.5 megadaltons) obtained by partial digestion with Sau 3A endonuclease and size fractionation on a sucrose density gradient were inserted into the dephosphorylated BamHI site of vector pBR322; CaCl2-treated Escherichia coli cells of strain HB101 were transformed with hybrid plasmids. To detect expression of antigens, 2,559 ampicillin-resistant transformants were transferred to nitrocellulose paper, lysed in situ, and screened by enzyme immunoassay (EIA) with E. coli-absorbed rabbit anti-L. pneumophila sera. A total of 77 (3%) of the colonies were reactive by EIA; 31 (1.2%) were strongly reactive, and 6 were strongly reactive by EIA without colony lysis. Analysis of 29 stable, strongly reactive clones by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and electroblotting showed antigenic bands in 18 clones by EIA with E. coli-absorbed antisera. Absorption of antisera with heat- and Formalin-killed L. pneumophila antigen eliminated or diminished the reactivity of the antigenic bands in representative clones. These studies confirm that several L. pneumophila antigens can be cloned and expressed in E. coli.

Identification of a carrier by using Vi enzyme-linked immunosorbent assay serology in an outbreak of typhoid fever on an Indian reservation

In May 1981 an outbreak of typhoid fever occurred in a small village on a southwestern United States Indian reservation. Five of the six culture-proven cases, but only 2 of 15 community, age-matched controls, had eaten food prepared for a party held in the village on 20 April (chi-square = 4.3; P less than 0.05). Food histories obtained from 16 persons who ate food at the party suggested that chicken with chili (P = 0.03) and potato salad (P = 0.09) were possible vehicles. Eleven adults who attended the party, 5 of whom helped prepare an implicated food, were studied with one or more stool cultures and serum for Vi antibody by using enzyme-linked immunosorbent assay (ELISA) and hemagglutination techniques. All initial stool cultures were negative for Salmonella typhi; however, one subject, a 70-year-old female foodhandler, had a Vi antibody titer of 1:320 by ELISA. Subsequent cultures from this subject were positive for S. typhi. ELISA for Vi antibody directed the investigators to a single individual as the most probable carrier source and obviated the need for multiple fecal cultures from the other potential carriers identified by the epidemiological investigation.

Epidemiology of diarrhea due to rotavirus on an Indian reservation: risk factors in the home environment

Analysis of outpatient visits for diarrheal disease at the San Carlos Apache Reservation, Arizona, during 1977-1979 revealed a sharp increase in cases of infantile gastroenteritis of unknown etiology in October and November of each year. During the 1980 autumn diarrhea season, 19 patients and 12 control subjects were selected from among outpatients under two years of age and were interviewed and studied for bacterial and viral enteric pathogens. Eleven (58%) of 19 patients and two (17%) of 12 control subjects were positive for fecal rotavirus by enzyme-linked immunosorbent assay (P = 0.03). Ten (91%) of 11 rotavirus-positive patients were under one year of age. The most significant risk factor for illness was the presence of a household contact under the age of two years (P - 0.004). Dog ownership was also associated with rotavirus infection (P = 0.05).